Abstract:
The invention provides compositions comprising a plurality of yeast cells, wherein said plurality of yeast cells are characterized by their ability to normalize the level of serum glutamate-pyruvate Transaminase (GPT), or reduce serum HBsAg levels in a subject, said ability resulting from their having been cultured in the presence of an alternating electric field having a specific frequency and a specific field strength. Also provided are methods of making and using these compositions.

Description:
FIELD OF THE INVENTION 
     The invention relates to compositions that can ameliorate or prevent hepatitis B and are useful as a dietary supplement or medication. These compositions contain yeast cells obtainable by growth in electromagnetic fields with specific frequencies and field strengths. 
     BACKGROUND OF THE INVENTION 
     Hepatitis is caused by viruses, bacteria, substance abuse, certain medicines, or serious structural damages to the liver. Most commonly, hepatitis is caused by one of three viruses: hepatitis A virus, hepatitis B virus, or hepatitis C virus. Hepatitis B, also called “serum hepatitis,” is caused by hepatitis B virus (HBV). HBV spreads through infected body fluids. Most hepatitis B patients recover from their illness completely within six months. However, some patients go on to develop chronic hepatitis and liver cirrhosis. These patients become lifelong carriers of HBV and can spread the virus to other people. 
     Hepatitis is a serious public health problem. It is estimated that there are over 350 million hepatitis B carriers worldwide, representing 5% of the world population. It is also estimated that 10 to 30 million people become infected with the virus every year. At present, the drug commonly used in the treatment of chronic hepatitis B is interferon. This treatment, however, does not work for everyone with chronic hepatitis B, and can cause strong side effects, such as flu-like symptoms, rashes, and depression. There remains a need for an effective method to treat hepatitis B. 
     SUMMARY OF THE INVENTION 
     This invention is based on the discovery that certain yeast cells can be activated by electromagnetic fields having specific frequencies and field strengths to produce substances beneficial for the liver. Compositions comprising these activated yeast cells can be used as a dietary supplement or medication for treating liver diseases, e.g., for alleviating or preventing hepatitis B. 
     This invention embraces a composition comprising a plurality of yeast cells that have been cultured in an alternating electric field having a frequency in the range of about 7900-12400 MHz (e.g., 7900-8100, 9850-10050, or 12200-12400 MHz), and a field intensity in the range of about 240-500 mV/cm (e.g., 260-280, 270-290, 290-320, 300-330, 310-340, 320-350, 330-360, 360-390, 400-440, or 430-470 mV/cm). The yeast cells are cultured in the alternating electric field for a period of time sufficient to substantially increase the capability of said plurality of yeast cells to produce substances beneficial for the liver (e.g., for treating hepatitis B). In one embodiment, the frequency and/or the field strength of the alternating electric field can be altered within the aforementioned ranges during said period of time. In other words, the yeast cells can be exposed to a series of electromagnetic fields. An exemplary period of time is about 40-160 hours (e.g., 60-145 hours). 
     Also included in this invention is a composition comprising a plurality of yeast cells that have been cultured under acidic conditions in an alternating electric field having a frequency in the range of about 9850-12400 MHz (e.g., 12200-12400 MHz) and a field strength in the range of about 270 to 420 mV/cm (e.g., 300-330 or 360-390 mV/cm). In one embodiment, the yeast cells are exposed to a series of electromagnetic fields. An exemplary period of time is about 40-110 hours (e.g., 58-78 hours). 
     Included in this invention are also methods for making the above compositions. 
     Yeast cells that can be included in this composition can be derived from parent strains publically available from the China General Microbiological Culture Collection Center (“CGMCC”), China Committee for Culture Collection of Microorganisms, Institute of Microbiology, Chinese Academy of Sciences, Haidian, P.O. BOX 2714, Beijing, 100080, China. Useful yeast species include, but are not limited to  Saccharomyces cerevisiae, Saccharomyces carlsbergensis, Saccharomyces rouxii, Saccharomyces sake, Saccharomyces uvarum, Saccharomyces  sp.,  Schizosaccharomyces pombe , and  Rhodotorula aurantiaca . For instance, the yeast cells can be of the strain  Saccharomyces cerevisiae  Hansen AS2.561 or AS2.69,  Saccharomyces  sp. AS2.311,  Schizosaccharomyces pombe  Lindner AS2.994,  Saccharomyces sake  Yabe ACCC2045,  Saccharomyces uvarum  Beijer IFFI1044,  Saccharomyces rouxii  Boutroux AS2.180,  Saccharomyces cerevisiae  Hansen Var. ellipsoideus AS2.612,  Saccharomyces carlsbergensis  Hansen AS2.377, or  Rhodotorula rubar  (Demme) Lodder AS2.282. Other useful yeast strains are illustrated in Table 1. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Exemplary methods and materials are described below, although methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention. All publications and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. The materials, methods, and examples are illustrative only and not intended to be limiting. Throughout this specification and claims, the word “comprise,” or variations such as “comprises” or “comprising” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 
     Other features and advantages of the invention will be apparent from the following detailed description, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing an exemplary apparatus for activating yeast cells using electromagnetic fields.  1 : yeast culture;  2 : container;  3 : power supply. 
         FIG. 2  is a schematic diagram showing an exemplary apparatus for making yeast compositions of the invention. The apparatus comprises a signal generator (such as models 83721B and 83741A manufactured by HP) and interconnected containers A, B and C. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This invention is based on the discovery that certain yeast strains can be activated by electromagnetic fields (“EMF”) having specific frequencies and field strengths to produce agents useful in treating liver diseases, e.g., hepatitis B. Yeast compositions containing activated yeast cells can be used as medication, or as a dietary supplement in the form of health drinks or dietary pills. 
     Since the activated yeast cells contained in these yeast compositions have been cultured to endure acidic conditions (pH 2.5-4.2), the compositions are stable in the stomach and can pass on to the intestines. Once in the intestines, the yeast cells are ruptured by various digestive enzymes, and the bioactive agents are released and readily absorbed. 
     I. Yeast Strains Useful in the Invention 
     The types of yeasts useful in this invention include, but are not limited to, yeasts of the genera of  Saccharomyces, Rhodotorula , and  Schizosaccharomyces.    
     Exemplary species within the above-listed genera include, but are not limited to, the species illustrated in Table 1. Yeast strains useful in this invention can be obtained from laboratory cultures, or from publically accessible culture depositories, such as CGMCC and the American Type Culture Collection, 10801 University Boulevard, Manassas, Va. 20110-2209. Non-limiting examples of useful strains (with the accession numbers of CGMCC) are  Saccharomyces cerevisiae  Hansen AS2.561 and AS2.69,  Saccharomyces  sp. AS2.311,  Schizosaccharomyces pombe  Lindner AS2.994,  Saccharomyces sake  Yabe ACCC2045,  Saccharomyces uvarum  Beijer IFFI1044,  Saccharomyces rouxii  Boutroux AS2.180,  Saccharomyces cerevisiae  Hansen Var. ellipsoideus AS2.612,  Saccharomyces carlsbergensis  Hansen AS2.377, and  Rhodotorula rubar  (Demme) Lodder AS2.282. Other non-limiting examples of useful strains are listed in Table 1. In general, preferred yeast strains in this invention are those used for fermentation in the food and wine industries. As a result, compositions containing these yeast cells are safe for human consumption. 
     The preparation of the yeast compositions of this invention is not limited to starting with a pure strain of yeast. A yeast composition of the invention may be produced by culturing a mixture of yeast cells of different species or strains. 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       TABLE 1               Exemplary Yeast Strains                     Saccharomyces cerevisiae  Hansen            ACCC2034   ACCC2035   ACCC2036   ACCC2037   ACCC2038       ACCC2039   ACCC2040   ACCC2041   ACCC2042   AS2. 1       AS2.4   AS2.11   AS2.14   AS2.16   AS2.56       AS2.69   AS2.70   AS2.93   AS2.98   AS2.101       AS2.109   AS2.110   AS2.112   AS2.139   AS2.173       AS2.174   AS2.182   AS2.196   AS2.242   AS2.336       AS2.346   AS2.369   AS2.374   AS2.375   AS2.379       AS2.380   AS2.382   AS2.390   AS2.393   AS2.395       AS2.396   AS2.397   AS2.398   AS2.399   AS2.400       AS2.406   AS2.408   AS2.409   AS2.413   AS2.414       AS2.415   AS2.416   AS2.422   AS2.423   AS2.430       AS2.431   AS2.432   AS2.451   AS2.452   AS2.453       AS2.458   AS2.460   AS2.463   AS2.467   AS2.486       AS2.501   AS2.502   AS2.503   AS2.504   AS2.516       AS2.535   AS2.536   AS2.558   AS2.560   AS2.561       AS2.562   AS2.576   AS2.593   AS2.594   AS2.614       AS2.620   AS2.628   AS2.631   AS2.666   AS2.982       AS2.1190   AS2.1364   AS2. 1396   IFFI1001   IFFI1002       IFFI1005   IFFI1006   IFFI1008   IFFI1009   IFFI1010       IFFI1012   IFFI1021   IFFI1027   IFFI1037   IFFI1042       IFFI1043   IFFI1045   IFFI1048   IFFI1049   IFFI1050       IFFI1052   IFFI1059   IFFI1060   IFFI1062   IFFI1063       IFFI1202   IFFI1203   IFFI1206   IFFI1209   IFFI1210       IFFI1211   IFFI1212   IFFI1213   IFFI1214   IFFI1215       IFFI1220   IFFI1221   IFFI1224   IFFI1247   IFFI1248       IFFI1251   IFFI1270   IFFI1277   IFFI1287   IFFI1289       IFFI1290   IFFI1291   IFFI1292   IFFI1293   IFFI1297       IFFI1300   IFFI1301   IFFI1302   IFFI1307   IFFI1308       IFFI1309   IFFI1310   IFFI1311   IFFI1331   IFFI1335       IFFI1336   IFFI1337   IFFI1338   IFFI1339   IFFI1340       IFFI1345   IFFI1348   IFFI1396   IFFI1397   IFFI1399       IFFI1411   IFFI1413   IFFI1441   IFFI1443              Saccharomyces cerevisiae  Hansen Var. ellipsoideus (Hansen) Dekker            ACCC2043   AS2.2   AS2.3   AS2.8   AS2.53       AS2.163   AS2.168   AS2.483   AS2.541   AS2.559       AS2.606   AS2.607   AS2.611   AS2.612              Saccharomyces chevalieri  Guilliermond            AS2.131   AS2.213                          Saccharomyces delbrueckii              AS2.285                              Saccharomyces delbrueckii         Lindner ver. mongolicus (Saito) Lodder et van Rij            AS2.209   AS2.1157                          Saccharomyces exiguous  Hansen            AS2.349   AS2.1158                          Saccharomyces fermentaii  (Saito) Lodder et van Rij            AS2.286   AS2.343                          Saccharomyces logos  van laer et Denamur ex Jorgensen            AS2.156   AS2.327   AS2.335                      Saccharomyces mellis  (Fabian et Quinet) Lodder et kreger van Rij            AS2.195                              Saccharomyces mellis  Microellipsoides Osterwalder            AS2.699                              Saccharomyces oviformis  Osteralder            AS2.100                              Saccharomyces rosei  (Guilliermond) Lodder et Kreger van Rij            AS2.287                              Saccharomyces rouxii  Boutroux            AS2.178   AS2.180   AS2.370   AS2.371                  Saccharomyces sake  Yabe            ACCC2045                              Candida arborea              AS2.566                              Candida lambica  (Lindner et Genoud) van. Uden et Buckley            AS2.1182                              Candida krusei  (Castellani) Berkhout            AS2.1045                              Candida lipolytica  (Harrison) Diddens et Lodder            AS2.1207   AS2.1216   AS2.1220   AS2.1379   AS2.1398       AS2.1399   AS2.1400              Candida parapsilosis  (Ashford) Langeron et Talice Var. intermedia       Van Rij et Verona            AS2.491                              Candida parapsilosis  (Ashford) Langeron et Talice            AS2.590                              Candida pulcherrima  (Lindner) Windisch            AS2.492                              Candida rugousa  (Anderson) Diddens et Lodder            AS2.511   AS2.1367   AS2.1369   AS2.1372   AS2.1373       AS2.1377   AS2.1378   AS2.1384              Candida tropicalis  (Castellani) Berkhout            ACCC2004   ACCC2005   ACCC2006   AS2.164   AS2.402       AS2.564   AS2.565   AS2.567   AS2.568   AS2.617       AS2.637   AS2.1387   AS2.1397              Candida utilis  Henneberg Lodder et Kreger Van Rij            AS2.120   AS2.281   AS2.1180                      Crebrothecium ashbyii  (Guillermond)       Routein ( Eremothecium ashbyii  Guilliermond)            AS2.481   AS2.482   AS2.1197                      Geotrichum candidum  Link            ACCC2016   AS2.361   AS2.498   AS2.616   AS2.1035       AS2.1062   AS2.1080   AS2.1132   AS2.1175   AS2.1183            Hansenula anomala (Hansen)H et P sydow            ACCC2018   AS2.294   AS2.295   AS2.296   AS2.297       AS2.298   AS2.299   AS2.300   AS2.302   AS2.338       AS2.339   AS2.340   AS2.341   AS2.470   AS2.592       AS2.641   AS2.642   AS2.782   AS2.635   AS2.794              Hansenula arabitolgens  Fang            AS2.887                              Hansenula jadinii  (A. et R Sartory Weill et Meyer) Wickerham            ACCC2019                              Hansenula saturnus  (Klocker) H et P sydow            ACCC2020                              Hansenula schneggii  (Weber) Dekker            AS2.304                              Hansenula subpelliculosa  Bedford            AS2.740   AS2.760   AS2.761   AS2.770   AS2.783       A52.790   AS2.798   AS2.866              Kloeckera apiculata  (Reess emend. Klocker) Janke            ACCC2022   ACCC2023   AS2.197   AS2.496   AS2.714       ACCC2021   AS2.711              Lipomycess starkeyi  Lodder et van Rij            AS2.1390   ACCC2024                          Pichia farinosa  (Lindner) Hansen            ACCC2025   ACCC2026   AS2.86   AS2.87   AS2.705       AS2.803              Pichia membranaefaciens  Hansen            ACCC2027   AS2.89   AS2.661   AS2.1039                  Rhodosporidium toruloides  Banno            ACCC2028                              Rhodotorula glutinis  (Fresenius) Harrison            AS2.2029   AS2.280   ACCC2030   AS2.102   AS2.107       AS2.278   AS2.499   AS2.694   AS2.703   AS2.704       AS2.1146              Rhodotorula minuta  (Saito) Harrison            AS2.277                              Rhodotorula rubar  (Demme) Lodder            AS2.21   AS2.22   AS2.103   AS2.105   AS2.108       AS2.140   AS2.166   AS2.167   AS2.272   AS2.279       AS2.282   ACCC2031              Rhodotorula aurantiaca  (Saito) Lodder            AS2.102   AS2.107   AS2.278   AS2.499   AS2.694       AS2.703   AS2.1146              Saccharomyces carlsbergensis  Hansen            AS2.113   ACCC2032   ACCC2033   AS2.312   AS2.116       AS2.118   AS2.121   AS2.132   AS2.162   AS2.189              Saccharomyces uvarum  Beijer            IFFI1023   IFFI1032   IFFI1036   IFFI1044   IFFI1072       IFFI1205   IFFI1207              Saccharomyces willianus  Saccardo            AS2.5   AS2.7   AS2.119   AS2.152   AS2.293       AS2.381   AS2.392   AS2.434   AS2.614   AS2.1189              Saccharomyces sp.              AS2.311                              Saccharomycodes ludwigii  Hansen            ACCC2044   AS2.243   AS2.508                      Saccharomycodes sinenses  Yue            AS2.1395                              Schizosaccharomyces octosporus  Beijerinck            ACCC2046   AS2.1148                          Schizosaccharomyces pombe  Lindner            ACCC2047   ACCC2048   AS2.214   AS2.248   AS2.249       AS2.255   AS2.257   AS2.259   AS2.260   AS2.274       AS2.994   AS2.1043   AS2.1149   AS2.1178   IFFI1056              Sporobolomyces roseus  Kluyver et van Niel            ACCC2049   ACCC2050   AS2.19   AS2.962   AS2.1036       ACCC2051   AS2.261   AS2.262              Torulopsis candida  (Saito) Lodder            AS2.270   ACCC2052                          Torulopsis famta  (Harrison) Lodder et van Rij            ACCC2053   AS2.685                          Torulopsis globosa  (Olson et Hammer) Lodder et van Rij            ACCC2054   AS2.202                          Torulopsis inconspicua  Lodder et Kreger van Rij            AS2.75                              Trichosporon behrendii  Lodder et Kreger van Rij            ACCC2056   AS2.1193                          Trichosporon capitatum  Diddens et Lodder            ACCC2056   AS2.1385                          Trichosporon cutaneum  (de Reurm et al.) Ota            ACCC2057   AS2.25   AS2.570   AS2.571   AS2.1374              Wickerhamia fluorescens  (Soneda) Soneda            ACCC2058   AS2.1388                                
II. Application of Electromagnetic Fields
 
     An electromagnetic field useful in this invention can be generated and applied by various means well known in the art. For instance, the EMF can be generated by applying an alternating electric field or an oscillating magnetic field. 
     Alternating electric fields can be applied to cell cultures through electrodes in direct contact with the culture medium, or through electromagnetic induction. See, e.g., FIG.  1 . Relatively high electric fields in the medium can be generated using a method in which the electrodes are in contact with the medium. Care must be taken to prevent electrolysis at the electrodes from introducing undesired ions into the culture and to prevent contact resistance, bubbles, or other features of electrolysis from dropping the field level below that intended. Electrodes should be matched to their environment, for example, using Ag—AgCl electrodes in solutions rich in chloride ions, and run at as low a voltage as possible. For general review, see Goodman et al.,  Effects of EMF on Molecules and Cells , International Review of Cytology, A Survey of Cell Biology, Vol. 158, Academic Press, 1995. 
     The EMFs useful in this invention can also be generated by applying an oscillating magnetic field. An oscillating magnetic field can be generated by oscillating electric currents going through Helmholtz coils. Such a magnetic field in turn induces an electric field. 
     The frequencies of EMFs useful in this invention range from about 7900 MHz to 12400 MHz (e.g., 7900-8100, 9850-10050, or 12200-12400 MHz). Exemplary frequencies include 7986, 8009, 9949, 12293, and 12312 MHz. The field strength of the electric field useful in this invention ranges from about 240-500 mV/cm (e.g., 260-280, 270-290, 290-320, 300-330, 310-340, 320-350, 330-360, 360-390, 400-440, or 430-470 mV/cm). Exemplary field strengths include 267, 272, 285, 298, 315, 317, 327, 337, 347, 375, 416, and 446 mV/cm. 
     When a series of EMFs are applied to a yeast culture, the yeast culture can remain in the same container while the same set of EMF generator and emitters is used to change the frequency and/or field strength. The EMFs in the series can each have a different frequency or a different field strength; or a different frequency and a different field strength. Such frequencies and field strengths are preferably within the above-described ranges. Although any practical number of EMFs can be used in a series, it may be preferred that the yeast culture be exposed to a total of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or more EMFs in a series. In one embodiment, the yeast culture is exposed to a series of EMFs, wherein the frequency of the electric field is alternated in the range of about 7900-8100, 9850-10050, and 12200-12400 MHz. 
     Although the yeast cells can be activated after even a few hours of culturing in the presence of an EMF, it may be preferred that the activated yeast cells be allowed to multiply and grow in the presence of the EMF(s) for a total of 40-160 hours. 
       FIG. 1  illustrates an exemplary apparatus for generating alternating electric fields. An electric field of a desired frequency and intensity can be generated by an AC source ( 3 ) capable of generating an alternating electric field, preferably in a sinusoidal wave form, in the frequency range of 5 to 20,000 MHz. Signal generators capable of generating signals with a narrower frequency range can also be used. If desired, a signal amplifier can also be used to increase the output. The culture container ( 2 ) can be made from a non-conductive material, e.g., glass, plastic or ceramic. The cable connecting the culture container ( 2 ) and the signal generator ( 3 ) is preferably a high frequency coaxial cable with a transmission frequency of at least 30 GHz. 
     The alternating electric field can be applied to the culture by a variety of means, including placing the yeast culture ( 1 ) in close proximity to the signal emitters such as a metal wire or tube capable of transmitting EMFs. The metal wire or tube can be made of red copper, and be placed inside the container ( 2 ), reaching as deep as 3-30 cm. For example, if the fluid in the container ( 2 ) has a depth of 15-20 cm, 20-30 cm, 30-50 cm, 50-70 cm, 70-100 cm, 100-150 cm or 150-200 cm, the metal wire can be 3-5 cm, 5-7 cm, 7-10 cm, 10-15 cm, 15-20 cm, 20-30 cm, and 25-30 cm from the bottom of the container ( 2 ), respectively. The number of metal wires/tubes used can be from 1 to 10 (e.g., 2 to 3). It is recommended, though not mandated, that for a culture having a volume up to 10 L, metal wires/tubes having a diameter of 0.5 to 2 mm be used. For a culture having a volume of 10-100 L, metal wires/tubes having a diameter of 3 to 5 mm can be used. For a culture having a volume of 100-1000 L, metal wires/tubes having a diameter of 6 to 15 nun can be used. For a culture having a volume greater than 1000 L, metal wires/tubes having a diameter of 20-25 mm can be used. 
     In one embodiment, the electric field is applied by electrodes submerged in the culture ( 1 ). In this embodiment, one of the electrodes can be a metal plate placed on the bottom of the container ( 2 ), and the other electrode can comprise a plurality of electrode wires evenly distributed in the culture ( 1 ) so as to achieve even distribution of the electric field energy. 
     III. Culture Media 
     Culture media useful in this invention contain sources of nutrients that can be assimilated by yeast cells. Complex carbon-containing substances in a suitable form (e.g., carbohydrates such as sucrose, glucose, dextrose, maltose, xylose, cellulose, starch, etc.) can be the carbon sources for yeast cells. The exact quantity of the carbon sources can be adjusted in accordance with the other ingredients of the medium. In general, the amount of carbohydrates varies between about 1% and 10% by weight of the medium and preferably between about 1% and 5%, and most preferably about 2%. These carbon sources can be used individually or in combination. Amino acid-containing substances such as beef extract and peptone can also be added. In general, the amount of amino acid containing substances varies between about 0.1% and 1% by weight of the medium and preferably between about 0.1% and 0.5%. Among the inorganic salts which can be added to a culture medium are the customary salts capable of yielding sodium, potassium, calcium, phosphate, sulfate, carbonate, and like ions. Non-limiting examples of nutrient inorganic salts are (NH 4 ) 2 HPO 4 , CaCO 3 , KH 2 PO 4 , K 2  HPO 4 , MgSO 4 , NaCl, and CaSO 4 . 
     IV. Electromagnetic Activation of Yeast Cells 
     To activate or enhance the ability of yeast cells to produce agents useful for treating live diseases (e.g., hepatitis B), these cells can be cultured in an appropriate medium under sterile conditions at 20-35° C. (e.g., 28-32° C.) for a sufficient amount of time (e.g., 60-145 hours) in an alternating electric field or a series of alternating electric fields as described above. 
     An exemplary set-up of the culture process is depicted in  FIG. 1  (see above). An exemplary culture medium contains the following per 1000 ml of sterile water: 18 g of mannitol, 50 μg of Vitamin B 6 , 50 μg of Vitamin B 12 , 50 μg of Vitamin B 3 , 100 □g of Vitamin H, 35 ml of fetal bovine serum, 0.2 g of KH 2 PO 4 , 0.25 g of MgSO 4 .7H 2 O, 0.3 g of NaCl, 0.2 g of CaSO 4 .2H 2 O, 4 g of CaCO 3 .5H 2 O, and 2.5 g of peptone. Yeast cells of the desired strain(s) are then added to the culture medium to form a mixture containing 1×10 8  cells per 1000 ml of culture medium. The yeast cells can be of any of the strains listed in Table 1. The mixture is then added to the apparatus shown in FIG.  1 . 
     The activation process of the yeast cells involves the following steps: (1) maintaining the temperature of the activation apparatus at 24-33° C. (e.g., 28-32° C.), and culturing the yeast cells for 24-30 hours (e.g., 28 hours); (2) applying an alternating electric field having a frequency of 7986 MHz and a field strength of 260-280 mV/cm (e.g., 267 mV/cm) for 11-17 hours (e.g., 15 hours); (3) then applying an alternating electric field having a frequency of 8009 MHz and a field strength of 310-340 mV/cm (e.g., 315 mV/cm) for 32-38 hours (e.g., 36 hours); (4) then applying an alternating electric field having a frequency of 9949 MHz and a field strength of 320-350 mV/cm (e.g., 337 mV/cm) for 38-44 hours (e.g., 42 hours); (5) then applying an alternating electric field having a frequency of 12293 MHz and a field strength of 330-360 mV/cm (e.g., 347 mV/cm) for 35-41 hours (e.g., 39 hours); and (6) then applying an alternating electric field having a frequency of 12312 MHz and a field strength of 260-280 mV/cm (e.g., 272 mV/cm) for 6-12 hours (e.g., 10 hours). The activated yeast cells are then recovered from the culture medium by various methods known in the art, dried (e.g., by lyophilization) and stored at 4° C. Preferably, the concentration of the dried yeast cells is no less than 10 10  cells/g. 
     V. Acclimatization of Yeast Cells to the Gastric Environment 
     Because the yeast compositions of this invention must pass through the stomach before reaching the small intestine, where the effective components are released from these yeast cells, it is preferred that these yeast cells be cultured under acidic conditions to acclimatize the cells to the gastric juice. This acclimatization process results in better viability of the yeast cells in the acidic gastric environment. 
     To achieve this, the yeast powder containing activated yeast cells can be mixed with a highly acidic acclimatizing culture medium at 10 g (containing more than 10 10  activated cells per gram) per 1000 ml. The yeast mixture is then cultured first in the presence of an alternating electric field having a frequency of 12293 MHz and a field strength of 360-390 mV/cm (e.g., 375 mV/cm) at about 28 to 32° C. for 42 to 50 hours (e.g., 46 hours). The resultant yeast cells can then be further incubated in the presence of an alternating electric field having a frequency of 12312 MHz and a field strength of 300-330 mV/cm (e.g., 317 mV/cm) at about 28 to 32° C. for 16 to 28 hours (e.g., 20 hours). The resulting acclimatized yeast cells are then dried and stored either in powder form (≧10 10  cells/g) at room temperature or in vacuum at 0-4° C. 
     An exemplary acclimatizing culture medium is made by mixing 700 ml fresh pig gastric juice and 300 ml wild Chinese hawthorn extract. The pH of the acclimatizing culture medium is adjusted to 2.5 with 0.1 M hydrochloric acid (HCl) and 0.2 M potassium hydrogen phthalate (C 6 H 4 (COOK)COOH). The fresh pig gastric juice is prepared as follows. At about 4 months of age, newborn Holland white pigs are sacrificed, and the entire contents of their stomachs are retrieved and mixed with 2000 ml of water under sterile conditions. The mixture is then allowed to stand for 6 hours at 4° C. under sterile conditions to precipitate food debris. The supernatant is collected for use in the acclimatizing culture medium. To prepare the wild Chinese hawthorn extract, 500 g of fresh wild Chinese hawthorn is dried under sterile conditions to reduce water content (≦8%). The dried fruit is then ground (≧20 mesh) and added to 1500 ml of sterilized water. The hawthorn slurry is allowed to stand for 6 hours at 4° C. under sterile conditions. The hawthorn supernatant is collected to be used in the acclimatizing culture medium. 
     VI. Manufacture of Yeast Compositions 
     To manufacture the yeast compositions of the invention, an apparatus depicted in  FIG. 2  or an equivalent thereof can be used. This apparatus includes three containers, a first container (A), a second container (B), and a third container (C), each equipped with a pair of electrodes ( 4 ). One of the electrodes is a metal plate placed on the bottom of the containers, and the other electrode comprises a plurality of electrode wires evenly distributed in the space within the container to achieve even distribution of the electric field energy. All three pairs of electrodes are connected to a common signal generator. 
     The culture medium used for this purpose is a mixed fruit extract solution containing the following ingredients per 1000 L: 300 L of wild Chinese hawthorn extract, 300 L of jujube extract, 300 L of  Schisandra chinensis  (Turez) Baill seed extract, and 100 L of soy bean extract. To prepare hawthorn, jujube and  Schisandra chinensis  (Turez) Baill seed extracts, the fresh fruits are washed and dried under sterile conditions to reduce the water content to no higher than 8%. One hundred kilograms of the dried fruits are then ground (≧20 mesh) and added to 400 L of sterilized water. The mixtures are stirred under sterile conditions at room temperature for twelve hours, and then centrifuged at 1000 rpm to remove insoluble residues. To make the soy bean extract, fresh soy beans are washed and dried under sterile conditions to reduce the water content to no higher than 8%. Thirty kilograms of dried soy beans are then ground into particles of no smaller than 20 mesh, and added to 130 L of sterilized water. The mixture is stirred under sterile conditions at room temperature for twelve hours and centrifuged at 1000 rpm to remove insoluble residues. To make the culture medium, these ingredients are mixed according to the above recipe, and the mixture is autoclaved at 121° C. for 30 minutes and cooled to below 40° C. before use. 
     One thousand grams of the activated yeast powder prepared as described above (Section V, supra) is added to 1000 L of the mixed fruit extract solution, and the yeast solution is transferred to the first container (A) shown in FIG.  2 . The yeast cells are then cultured in the presence of an alternating electric field having a frequency of 12293 MHz and a field strength of about 400-440 mV/cm (e.g., 416 mV/cm) at 28-32° C. under sterile conditions for 32 hours. The yeast cells are further incubated in an alternating electric field having a frequency of 12312 MHz and a field strength of 290-320 mV/cm (e.g., 298 mV/cm). The culturing continues for another 12 hours. 
     The yeast culture is then transferred from the first container (A) to the second container (B) which contains 1000 L of culture medium (if need be, a new batch of yeast culture can be started in the now available first container (A)), and subjected to an alternating electric field having a frequency of 12293 MHz and a field strength of 430-470 mV/cm (e.g., 446 mV/cm) for 24 hours. Subsequently the frequency and field strength of the electric field are changed to 12312 MHz and 260-280 mV/cm (e.g., 272 mV/cm), respectively. The culturing continues for another 12 hours. 
     The yeast culture is then transferred from the second container (B) to the third container (C) which contains 1000 L of culture medium, and subjected to an alternating electric field having a frequency of 12293 MHz and a field strength of 310-340 mV/cm (e.g., 327 mV/cm) for 24 hours. Subsequently the frequency and field strength of the electric field are changed to 12312 MHz and 270-290 mV/cm (e.g., 285 mV/cm), respectively. The culturing continues for another 12 hours. 
     The yeast culture from the third container (C) can then be packaged into vacuum sealed bottles for use as a dietary supplement, e.g., health drinks, or medication in the form of pills, powder, etc. If desired, the final yeast culture can also be dried within 24 hours and stored in powder form. The dietary supplement can be taken three to four times daily at 30-60 ml per dose for a three-month period, preferably 10-30 minutes before meals and at bedtime. 
     In some embodiments, the compositions of the invention can also be administered intravenously or peritoneally in the form of a sterile injectable preparation. Such a sterile preparation can be prepared as follows. A sterilized health drink composition is first treated under ultrasound (20,000 Hz) for 10 minutes and then centrifuged for another 10 minutes. The resulting supernatant is adjusted to pH 7.2-7.4 using 1 M NaOH and subsequently filtered through a membrane (0.22 μm for intravenous injection and 0.45 μM for peritoneal injection) under sterile conditions. The resulting sterile preparation is submerged in a 35-38° C. water bath for 30 minutes before use. In other embodiments, the compositions of the invention may also be formulated with pharmaceutically acceptable carriers to be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, suspensions or solutions. 
     The yeast compositions of the present invention are derived from yeasts used in food and pharmaceutical industries. The yeast compositions are thus devoid of side effects associated with many pharmaceutical compounds. 
     VII. EXAMPLES 
     The following examples are meant to illustrate the methods and materials of the present invention. Suitable modifications and adaptations of the described conditions and parameters which are obvious to those skilled in the art are within the spirit and scope of the present invention. 
     The activated yeast compositions used in the following experiments were prepared as described above, using  Saccharomyces cerevisiae  Hansen AS2.561 cells cultured in the presence of an alternating electric field having the electric field frequency and field strength exemplified in the parentheses following the recommended ranges listed in Section IV, supra. Control yeast compositions were those prepared in the same manner except that the yeast cells were cultured in the absence of EMFs. Unless otherwise indicated, the yeast compositions and the corresponding controls were administered to the animals by intragastric feeding. 
     Example 1 
     Effects of Yeast Compositions against HBsAg 
     The HBV surface coat is composed of hepatitis B surface antigens (“HBsAg”). HBsAg is produced in larger quantities than required for the virus to reproduce. The excess surface antigens clump into spherical particles or form rods of variable length. These spherical particles can also encapsulate a core particle and produce a complete and infectious viral particle that enters the blood stream and infects other liver cells. The excess spheres, rods and complete viral particles enter the blood stream in large numbers and are easily detectable. HbsAg-positivity is the current standard used to indicate HBV infection. The presence of HBsAg for more than six months is generally taken to indicate chronic infection. 
     In this experiment, the effectiveness of the activated yeast composition in reducing HBsAg level was assessed using an ELISA assay. 
     Preparation of Yeast Compositions for ELISA: 
     Under sterile conditions, a bottle (100 ml/bottle, about 10 8  cells/ml) of the activated yeast composition (AY) was mixed with 100 ml of de-ionized H 2 O in a 200 ml beaker and the mixture incubated at 28-30° C. for two hours. The mixture was then sonicated at 3000 Hz for 15 minutes and centrifuged at 1000 rpm for 10 minutes. The supernatant was then filtered through a 0.45 μm membrane. De-ionized water was added to bring the volume to 100 ml. The pH of the solution was adjusted to 7.0 with 0.1 M NaOH and HCl, and then stored at 4° C. Before use, three different concentrations of the solution were prepared: 1×50 μl (stock solution without further concentration), 2×50 μl (100 μl of stock solution concentrated to 50 μl), and 3×50 μl (150 μl of stock solution concentrated to 50 μl). Control yeast composition solutions (NY) were prepared in the same way. 
     Preparation of HBsAg Solutions: 
     HBsAg was purified from HBsAg positive serum (with a titer of 1:8) using cellulose ion-exchange affinity chromatography. The preparation was stored in aliquots at 4° C. Two HBsAg concentrations were used for this experiment: P/N (Positive/Negative)=10.92, and P/N=14.26. P/N is the ratio between the HBsAg concentration of an HbsAg-positive serum and that of an HbsAg-negative serum. 
     Experimental Procedure: 
     Six solutions were prepared by mixing 50 μl of the yeast composition solutions at three different concentrations with 50 μl of the HBsAg preparations at two different concentrations. HBsAg positive (where no yeast composition solution was added) and HBsAg negative (no HBsAg) controls, as well as a blank control (where H 2 O was used in lieu of yeast composition and HBsAg) were also included. These mixtures were incubated at 37° C. for four hours. The ELISA plate were coated with 100 μl of purified hepatitis B surface antibody (“HbsAb”) per well at 4° C. for 48 hours. The plates were then washed several times with wash buffer and spun dry. The yeast composition solution-HBsAg mixtures and the various controls were each added to a HBsAb-coated well and incubated at 43° C. for two hours. The plates were washed several times and spun dry, and 100 μl of HRP-HBsAb (1:100) in 10% fetal bovine serum was added per well and incubated at 43° C. for one hour. The plates were then washed several times and spun dry. 100 μl of o-phenylenediamine-hydrogen peroxide was added per well. After incubation at 37° C. in the dark for 30 minutes, the reactions were stopped by adding 50 μl of 2 M H 2 SO 4  per well. The optical density of the samples was measured at 492 nm, using the blank sample for calibration. The P/N values of the reactions were calculated based on the average OD values (i.e., OD value for the samples divided by the OD value of the negative control). The data are shown in Table 2 below. 
     
       
         
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 P/N when 
                   
               
               
                   
                 HBsAg P/N = 14.26 
                 P/N when HBsAg P/N = 10.92 
               
             
          
           
               
                   
                 1X50 
                 2X50 
                 3X50 
                 1X50 
                 2X50 
                 3X50 
               
               
                 Group 
                 (50 μl) 
                 (50 μl) 
                 (50 μl) 
                 (50 μl) 
                 (50 μl) 
                 (50 μl) 
               
               
                   
               
             
          
           
               
                 AY 
                 0.95 
                 0.44 
                 0.18 
                 0.42 
                 0.19 
                 0.11 
               
               
                 NY 
                 14.11 
                 14.03 
                 13.96 
                 10.86 
                 10.63 
                 10.34 
               
               
                   
               
             
          
         
       
     
     The data demonstrate that the activated yeast composition significantly reduced the level of HBsAg (P/N&lt;0.95) compared to the control yeast composition (P/N&gt;10.34). By general medical standards, a P/N value of &lt;1.2 indicates significant effect of treatment; a P/N value of &lt;2.1, average effect; a P/N value of 3.8-4.25, low effect; and a P/N value of &gt;4.25, no effect. 
     Example 2 
     Effects of Yeast Compositions on Glutamate-Pyruvate Transaminase Activity 
     Glutamate-pyruvate transaminase (GPT) normally is expressed in hepatocytes. When the liver tissue undergoes necrosis or is otherwise damaged, GPT is released into the blood stream, elevating the level of serum GPT. Thus, the serum GPT level is one of the important indicators of liver functions. 
     To evaluate the effects of the activated yeast composition of this invention on serum GPT activity, the yeast compositions were tested in patients with chronic hepatitis B (either Chronic Persistent Hepatitis B or Chronic Active Hepatitis B). The study was conducted under the direction of physicians. 
     In this study, the patients with Chronic Persistent Hepatitis B or Chronic Active Hepatitis B (these two groups of patients were studied separately) were randomly divided into three groups, namely AY (for treatment with the activated yeast composition), NY (for treatment with the control yeast composition), CK (positive control group, for treatment with Stronger Neominophagen C, or SNMC, a known drug for treating hepatitis B). The AY group patients were each given 30 ml of the activated yeast composition (about 10 8  cells/ml), three times daily for six months. The NY patients were treated in the same manner except that they were given the control yeast composition, in lieu of the activated yeast composition. The CK patients were each given 40 ml of SNMC (1.0 mg/ml) via intraveinous injection daily for six months. 
     At the end of the sixth month, blood samples were taken from each patient to determine the serum GPT level. To do so, 0.1 ml of serum from each paitent was mixed with 0.5 ml of the glutamate-pyruvate substrate solution (1 M) and incubated in a 37° C. water bath for 30 minutes. Then 0.5 ml of 2,4-dinitrophenylhydrazine was added and the incubation continued for another 20 minutes. Finally, 5 ml of 0.4 M NaOH was added. The control reaction was prepared in the same manner except that the serum was added immediately after, not before, the 30 minute incubation step. The optical density of the sample was measured at 520 nm, using the control reaction for calibration. The GPT concentration was determined using a standard curve. Data in Table 3 below show that the number of patients in each group whose serum GPT level returned to normal after treatment. 
     
       
         
               
               
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
             
             
               
                   
                   
               
               
                   
                 Patients with 
                 Patients with 
               
               
                   
                 Chronic Persistent 
                 Chronic Active 
               
               
                   
                 Hepatitis B 
                 Hepatitis B 
               
             
          
           
               
                   
                 After Treatment 
                   
                 After Treatment 
               
             
          
           
               
                   
                   
                 # of 
                 % of 
                   
                 # of 
                 % of 
               
               
                   
                   
                 Patients 
                 Patients 
                   
                 Patients 
                 Patients 
               
               
                   
                 Total # 
                 with 
                 with 
                 Total # 
                 with 
                 with 
               
               
                   
                 of 
                 Normal 
                 Normal 
                 of 
                 Normal 
                 Normal 
               
               
                 Group 
                 Patients 
                 [GPT] 
                 [GPT] 
                 Patients 
                 [GPT] 
                 [GPT] 
               
               
                   
               
             
          
           
               
                 AY 
                 22 
                 19 
                 86.3 
                 26 
                 22 
                 84.6 
               
               
                 NY 
                 23 
                 0 
                 0 
                 25 
                 0 
                 0 
               
               
                 CK 
                 20 
                 3 
                 15.0 
                 27 
                 4 
                 14.8 
               
               
                   
               
             
          
         
       
     
     The data demonstrate that the activated yeast composition significantly restored serum GPT to normal levels in patients with chronic hepatitis B, and was superior to SNMC in doing so. 
     While a number of embodiments of this invention have been set forth, it is apparent that the basic constructions may be altered to provide other embodiments which utilize the compositions and methods of this invention.