bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of the Vegetation in Experimental
Streptococcus viridans
Endocarditis
Authors: Hook Edward W. , Sande Merle A.
Published: January 2020

This study examines the role of the vegetation in catheter-induced experimental endocarditis in predisposing to bacterial colonization of cardiac valves and in influencing the course of the disease and response to penicillin therapy. Platelet-fibrin vegetations developed at areas of valvular trauma and were colonized when
Streptococcus viridans
were injected intravenously. Pretreatment with warfarin prevented vegetation formation, but animals still developed endocarditis at the same rate after injection of 10
6
S. viridans
. The course of the disease in anticoagulated animals was more explosive, as determined by a more rapid rise in fever and level of bacteremia. Mean survival was shorter in anticoagulated rabbits (7 versus 12.7 days). Large vegetations containing 10
9
S. viridans
/g were found in control animals, whereas anticoagulated rabbits developed only microscopic deposits. Large vegetations required a longer duration of penicillin therapy to sterilize than the infected valves of the anticoagulated group (7 versus 3 days). Therefore, a preformed platelet-fibrin deposit is not a prerequisite for bacterial colonization of cardiac valves. After infection, the vegetation is an important factor in determining the subacute course of disease and resistance to penicillin therapy.
Inability to Detect Hepatitis B Virus or Specific Antigens in Transformed Chimpanzee Lymphocytes
Authors: Schable C. A. , Murphy B. L. , Berquist K. R. , Gravelle C. R. , Maynard J. E.
Published: January 2020

Transformed chimpanzee lymphocytes were examined to determine whether they would support the replication of hepatitis B virus. After 5 months, no hepatitis B virus, hepatitis B surface antigen, or antibody to hepatitis B surface antigen was detected.
Influence of Culture Medium on the Glucosyl Transferase- and Dextran-Binding Capacity of
Streptococcus mutans
6715 Cells
Authors: Spinell D. M. , Gibbons R. J.
Published: January 2020

Growth of
Streptococcus mutans
6715 in a medium containing trace amounts of sucrose or dextran promotes cell-associated glucosyl transferase activity and increases the dextran-binding capacity of the organisms.
Hepatitis B antigen in saliva, urine, and stool
Authors: Irwin G R , Allen A M , Bancroft W H , Karwacki J J , Brown H L , Pinkerton R H , Willhight M , Top F H
Published: January 2020

A survey of hepatitis B patients, asymptomatic hepatitis B antigen (HBsAg) carriers, and control subjects was conducted to determine the relationship between antigenemia and antigen excretion in saliva, urine, and stool. Radioimmunoassay was used to detect HBsAg. Specificity-confirmed HBsAg was detected in the saliva of 6 (30%) of 20 antigenemic patients, 1 (5%) of 20 nonantigenemic patients, 14 (34%) of 41 carriers, and 0 of 112 controls. HBsAg was detected in urine only after 100-fold concentration of first-morning specimens. Specificity-confirmed HBsAg was present in the urine of 7 (16%) of 43 carriers; unconfirmed HBsAg was found in the urine of 5 (13%) of 38 patients and 5 (5%) of 112 controls. Unconfirmed HBsAg was detected in concentrated stool specimens from 5 (46%) of 11 patients and 3 of 8 carriers and controls. Longitudinally collected specimens from antigenemic subjects showed no consistent patterns of antigen excretion.
Fowl immunoglobulins: quantitation and antibody activity during Marek's disease in genetically resistant and susceptible birds
Authors: Higgins D A , Calnek B W
Published: January 2020

Five-week-old birds of resistant (N) and susceptible (P) genetic lines were inoculated with the JM strain of Marek's disease (MD) virus. MD occurred only in P-line birds; one-third had died by the end of the experiment (63 days after inoculation). Sera were examined for antibodies (precipitating, virus neutralizing,and fluorescing), and immunoglobulins were measured. Antibodies were associated with immunoglobulin classes by density gradient centrifugation and utilization of specific antisera to gowl immunoglobulins in indirect immunofluorescence. Precipitating antibodies were found in both lines; they first appeared 7 days after inoculation in P-line birds and 14 days after inoculation in N-line birds, but thereafter there was no difference between the two genetic lines. A peak of neutralizing antibody occurred in both lines between 6 and 12 days. Thereafter neutralizing antibodies increased gradually throughout the experiment. Neutralizing antibody levels were at this stage often higher in N-line than in P-line birds. The fluorescent antibody test showed transient immunoglobulin (Ig) M antibody from 7 to 9 days in N-line birds and 5 to 12 days in P-line birds; this corresponded with the initial peak of neutralizing antibody. Antibodies were seen from 7 to 8 days after inoculation and increased gradually durin gthe experiment, generally paralleling the secondary increase in neutralizing antibodies. Ultracentrifugation confirmed the presence of IgM and IgG antibodies as described. Antibodies of the IgA class were not found. The alterations in serum immunoglobulin levels occurred in three phrases: (i) 1 to 9 days postinfection, there was an increase in IgM and IgA compared with uninfected control birds; (ii) 10 to 20 days postinfection, Ig M and IgA levels were lower than in control birds; and (iii) 21 days postinfection, until the end of experiment, IgA returned to normal levels, IgG increased to about eight times higher than in control birds, and IgM in P-line birds returned to normal levels and in N-line birds reached and maintained levels about double those of control birds. Another experiment was designed to examine the separate effects of moving and inoculation of uninfected kidney cells and virus-infected kidney cells. The changes in immunoglobulins observed in the first experiment occurred only after infection with MD virus and were not related to movement or handling stress. It was concluded that no significant primary difference exists in the humoral immune system between fowls resistant and susceptible to MD; all differences could be related to the immunosuppressive effects of MD, which are greater in susceptible birds apparently due to the greater lymphoid tissue damage in these strains.
Antibody response to Epstein-Barr virus in infectious mononucleosis
Authors: Nikoskelainen J , Hänninen P
Published: January 2020

Altogether 171 serum specimens from 58 patients with heterophil antibody-positive infectious monomucleosis were studied for antibody response to Epstein-Barr virus (EBV). The sera were tested for fluorescent immunoglobulin G (IgG) and IgM gel-precipitating (GP) and complement-fixing (CF) antibodies to EBV. All 58 patients had IgG and IgM antibodies to EBV. Both IgG and IgM antibodies developed rapidly; the IgM antibodies disappeared within 8 to 10 weeks, whereas the IgG antibodies remained at an almost constant level. The development of IgG antibodies was so rapid that a fourfold or greater rise in titers was noted only in 22% of the patients. Both GP and CF antibodies to EBV (crude P3HR-1 Burkitt cell antigen) developed slowly; the mean titers kept rising for more than 12 weeks. The micro GP technique seemed to be more sensitive than the CF method, because 86% of the patients with infectious mononucleosis had GP antibodies compared with 72% having CF antibodies. In patients with infectious mononucleosis, a seroconversion or significant rise in GP antibodies was noted in 57%, whereas only 19% had a similar change in CF antibodies. The most promising of these antibody assays in the diagnosis of recent infections was the EBV-specific IgM antibody technique, which enables one to make the diagnosis on the basis of only one serum specimen. In cases where the acute-phase serum specimen is missing, the diagnosis can be made later by using the GP and CF techniques.
Phagocytosis of Cryptococcus neoformans by alveolar macrophages
Authors: Bulmer G S , Tacker J R
Published: January 2020

Guinea pig pulmonary macrophages phagocytized but did not kill nonencapsulated cells of Cryptococcus neoformans. The phagocytic process was inhibited by cryptococcal capsular polysaccharide. Pulmonary macrophages, activated by preinjecting heat-killed bacteria into intact animals, did not kill the engulfed yeast cells. Labeled cells of C. neoformans were neither killed nor cleared from guinea pig lungs 6 h postexposure. The results of our experiments indicate that during the first few hours after the lung is exposed to the infectious particle of C. neoformans the pulmonary macrophage does not function primarily to kill engulfed yeast cells. We believe that a rapid yet transient acute inflammatory response probably plays a major role in this process during the first few hours after C. neoformans enters the lung.
Effect of local infection and oral contraception on immunoglobulin levels in cervical mucus
Authors: Chipperfield E J , Evans B A
Published: January 2020

The concentrations of immunoglobulin A (IgA) and immunoglobulin G (IgG) were estimated in cervical mucus from 115 patients attending a clinic for sexually transmitted diseases. The patients were divided into two groups; those using combined estrogen/progestogen oral contraceptives, and those with presumed normal ovulatory cycles. Gonorrhea, trichomoniasis, candidosis, and herpes genitalis were diagnosed by conventional smear and culture techniques, and the two groups were subdivided according to these diagnoses. Gonorrhea, trichomoniasis, herpetic, and nonspecific cervicitis all caused marked increases in the mean concentrations when compared with a control group of uninfected patients with natural cycles (P = less than 0.01). Patients with candidosis and contacts of men with nonspecific urethritis showed a lesser rise. IgG/IgA ratios lower than that of serum suggested a considerable locally produced contribution of IgA. Oral contraception with the combined pill also caused a significant increase in mean IgA and IgG levels even in the absence of local infection (P = less than 0.01). an increase in the IgG/IgA ratio of this group may indicate that the hormonal effect was manifest through increased serum transudation. IgM was also detected more commonly in patients taking the pill. The marked effect of local disease on immunoglobulin levels in cervical mucus which occurs even in asymptomatic patients emphasizes the importance of screening for infection when studying these secretions.
Bovine veneral vibriosis: antigenic variation of the bacterium during infection
Authors: Corbeil L B , Schurig G G , Bier P J , Winter A J
Published: January 2020

Host parasite relationships in the female genital tract were studied in bovine venereal vibriosis by investigating agglutinin production and alterations in superficial antigens of the bacterium during the course of infection in two heifers. Cervicovaginal mucus (CVM) steamed cell agglutinins were shown to appear earlier and remain at consistently higher levels than whole-cell agglutinins. Whole-cell agglutinin titers fluctuated much more than steamed cell titers, suggesting possible changes in whole-cell antigens. Marked antigenic variation was demonstrated in successive monthly CVM isolates from the two heifers by agglutination tests with rabbit antisera of various specificities. Some changes in CVM antibody specificity during the infection were noted also. Antigenic variation in the bacterium was proposed as a mechanism for maintenance of the asymptomatic cervicovaginal carrier state in the presence of antibody.
Effect of prednisolone on the leukocyte counts of ponies and on the reactivity of lymphocytes in vitro and in vivo
Authors: Targowski S P
Published: January 2020

Treatment of ponies with a single dose of prednisolone markedly reduced the number of blood lymphocytes. A decrease of the number of eosinophils was also observed. In contrast, the number of neutrophils significantly increased. These profound changes were temporary and returned to the pretreatment level within 48 h. The number of monocytes did not show any of the significant changes post-prednisolone treatment. The reactivity of the blood lymphocytes of these ponies, in vitro, to stimulation with phytohemagglutinin (PHA) or streptokinase-strepto-dornase (SK-SD) was measured by incorporation of (3-H)thymidine by deoxyribonucleic acid of lymphocytes. The ponies' blood lymphocytes responded very well to PHA stimulation. The incorporation of (3-H)thymidine into deoxyribonucleic acid of the PHA-stimulated lymphocytes was 14 times greater than incorporation of the nonstimulated lymphocytes. SK-SD-stimulated lymphocytes incorporated only three times more (3-H)thymidine than nonstimulated lymphocytes. There was no significant difference in stimulation of lymphocytes with PHA or SK-SD before or after the prednisolone treatment. However, a significant decrease in the dermal response to the homologous antigen after this treatment in sensitive ponies was observed.
Detection and serological identification of adeno-associated virus in avian adenovirus stocks
Authors: El Mishad A M , McCormick K J , Yates V J , Trentin J J
Published: January 2020

Eleven avian adenovirus strains were tested for the presence of avian adeno-associated viruses (AAAV). Six strains contained AAAV. Electron microscopy using rabbit anti-AAAV serum was useful in detecting the satellite virus. The AAAV previously isolated from guail bronchitis virus was related to each of the six new isolates by immunoagglutination, complement fixation, immunodiffusion, and neutralization tests.
In vitro interaction of Bacteroides fragilis with polymorphonuclear leukocytes and serum factors
Authors: Casciato D A , Rosenblatt J E , Goldberg L S , Bluestone R
Published: January 2020

The sera and polymorphonuclear leukocytes (PMNs) of healthy human subjects were tested against several isolates of Bacteroides fragilis. All sera killed most of the fecal isolates, but were active aganist only one of the clinical isolates. The degree of killing was directly related to the serum concentration but was independent of the bacterial inoculum within the range of bacterial concentrations studied. The serum bactericidal activity was heat-labile. Engulfment and killing of B. fragilis by PMNs were demonstrated consistently. The opsonim involved in phagocytosis was also heat liable. Calculations involving log-transformed data permitted the quantitative study of the separate and combined effects of serum and PMNs on bacteria which were killed by serum alone. Whereas serum alone usually killed 0.5 log of serum-sensitive bacteria, the addition of PMNs was usually associated with one log further killing. The studies reported here demonstrate the presence of heat-labile serum factors in normal human sera which killed B. fragilis directly and which promote its phagocytosis and killing by PMNs. These observations provide a foundation for investigations into host defense mechanisms against anaerobes.
Immunological studies on Histoplasma capsulatum
Authors: De Sanchez S B , Carbonell L M
Published: January 2020

Alveolar macrophages freshly harvested from normal and immunized rabbits were parasitized with yeast cells and protoplasts of Histoplasma capsulatum. Macrophages obtained from either normal or sensitized rabbits failed to phagocytize protoplasts, whereas, the yeast cells were actively ingested. There was no detectable intracellular killing by macrophages. A serological similarity was found between the whole yeast cell, the purified isolated cell wall, and the protoplasts of the fungus. Aprecipitin test of the protoplasts of the fungus gave a postive band, whereas immunodiffusion in agar was negative. Addition of immune sera activated phagocytosis, the immune sera against cell walls being the most active.
Genetic basis of toxin production and pathogenesis in Vibrio cholerae: evidence against phage conversion
Authors: Gerdes J C , Romig W R
Published: January 2020

The pathogenicity of Vibrio cholerae strains "cured" of "Kappa-type" phage was not significantly altered relative to that of their "Kappa" lysogenic parental strains. Unlike Corynebacterium diphtheriae, the capacity of V. cholerae to produce exotoxin was not stimulated as a consequence of active phage multiplication. Toxin production in cultures in which Kappa-type phage multiplication was initiated either by inducing Kappa lysogens or by infecting naturally occurring or "cured" Kappa-sensitive strains was greatly reduced compared to normally growing control cultures. Kappa-sensitive El Tor strain Mak 757 and a Kappa lysogen derived from it did not differ in their capacity to colonize ligated rabbit ileal loops nor in their sensitivites to ultraviolet radiation, acidic pH, or osmotic shock. We conclude that Kappa-type phages do not directly affect the pathogenicity of these V. cholerae strains.
Naturally occurring persistent feline oncornavirus infections in the absence of disease
Authors: Essex M , Hardy W D , Cotter S M , Jakowski R M , Sliski A
Published: January 2020

Healthy feline leukemia virus (FeLV)-infected cats from leukemia cluster environments were followed for up to 23 months for development of disease and evidence of alteration in the hemogram. The incidence of disease development in FeLV-postive cats was more than fivefold higher than the incidence for FeLV-negative cats. Ten cases of leukemia developed in 69 infected cats, whereas one case of leukemia occurred in 59 uninfected cats. The incidence for development of diseases other than leukemia was 30.4 percent for FeLV-infected cats as opposed to 6.8 per cent for uninfected cats. This could be a result of the immunosuppressive effects of FeLV. Felv-infected cats had no evidence of subclinical anemia. Mean packed cell volumes and total leukocyte counts were about the same for infected and uninfected animals. The only variation seen in healthy FeLV-infected cats was a decreased mean lymphocyte count. The difference between mean lymphocyte count for FeLV-infected and uninfected animals was significant at the 0.999 level. These findings suggest that the incubation period for feline leukemia may be very prolonged under natural conditions and that an increased susceptibility to unrelated infectious diseases exists during this period. This increased susceptibility was apparently not associated with anemia or depressed total leukocyte counts.
Superficial antigens of Campylobacter (Vibrio) fetus: characterization of antiphagocytic component
Authors: McCoy E C , Doyle D , Burda K , Corbeil L B , Winter A J
Published: January 2020

A glycoprotein responsible for the antiphagocytic properties of Campylobacter fetus has been identified by comparing cells of a wild-type strain with those of a mutant lacking this substance. The antiphagocytic component is demonstrable through electron microscopy as a discrete, negatively charged structure on the periphery of the cell. CLT is readily removed from the cell by mild extraction procedures and contributes to the inagglutinability in O antiserum normally displayed by C. fetus. Cells possessing this antigen are refractory to ingestion by macrophages except in the presence of specific antiserum. In its absence maximum phagocytosis occurs without a requirement for opsonins. It is concluded that the antiphagocytic component comprises a critical virulence factor of the bacterium.
Some effects of growth medium composition on the antigenicity of a T-strain mycoplasma
Authors: Masover G K , Mischak R P , Hayflick L
Published: January 2020

T-strain 960 was passaged through 24 serial 10-fold dilutions in media without added urea and with porcine serum albumin fraction V as the only protein enrichment. The organism, either grown in this manner or passaged an additional three times in medium containing horse serum and 0.1 per cent urea, was inoculated into rabbits. Resultant antisera were tested for activity against T-960 growing in these different media by: (i) growth curve analysis in the presence of antiserum, (ii) metabolic inhibition in the presence or absence of complement (fresh guinea pig serum), (iii) complement-dependent killing curves, (iv) double diffusion in gel (Ouchterlong), and (v) a new visual method for the detection of antigen-antibody reactions on glass slides coated with a thin film of indium metal. Our results indicate that the reactivity of the antisera, as assayed by the above methods, is significantly affected by the composition of the growth medium used for preparation of the antigen. In addition, it was possible to determine that the guinea pig serum-dependent killing of T960 was not affected by the presence of ammonium ion.
Adenovirus-transformed cells restrict Herpes simplex virus replication
Authors: Tucker A G , Docherty J J
Published: January 2020

A cell line that normally supports the replication of herpes simplex virus types 1 and 2 became resistant to these viruses after transformation by simian adenovirus 7. Kinetic studies of the mechanism of resistance demonstrated that both herpesviruses were able to attach to the transformed cells and express some early genomic functions, as demonstrated by the presence of low levels of viral thymidine kinase. However, isopycnic centrifugation studies of the abortive system failed to detect viral deoxyribonucleic acid synthesis, whereas indirect immunofluorescent studies of viral proteins revealed that less than 10 per cent of the cells contained these viral macromolecules at any given time. Collectively the data suggest that after transformation by simian adenovirus 7 these cells are altered so as to render them resistant or incapable of supporting the growth of herpes simplex virus types 1 and 2. The results further suggest that the block occurs after viral absorption and prior to viral deoxyribonucleic acid synthesis.
Enterotoxin formation by different toxigenic types of Clostridium perfringens
Authors: Skjelkvålé R , Duncan C L
Published: January 2020

Sixty-nine strains of Clostridium perfringens of different toxigenic types were investigated for enterotoxin production. Enterotoxin was definitively detected only in strains of types A and C. This is the first report where enterotoxin production has been demonstrated in a toxigenic type other than type A. The exterotoxin-positive type C strains were isolated from cases of enteritis necroticans ("pig bel+) in New Guinea. The major enterotoxin from type C showed a reaction of complete identity with enterotoxin from type A in immunodiffusion using anti-enterotoxin serum prepared against the latter; it induced erythema when injected intradermally into depilated guinea pigs and caused fluid accumulation in the rabbit ileal loop. The results indicate that the major enterotoxin from type C was serologically and biologically similar to enterotoxin from type A. In some C was serologically and biologically similar to enterotoxin from type A. In some type C strains, an enterotoxin was detected that showed a reaction of partial serological identity. Spore coat proteins were extracted from 14-strains by alkaline dithiothreitol, and the extracts were assayed for enterotoxin-like spore protein. Enterotoxin could be extracted from type A and type C spores, and all positive strains showed a reaction of complete identity in immunodiffusion with enterotoxin obtained from cell extracts of type A. Disc immunoelectrophoresis demonstrated that two distinct components that reacted serologically with anti-enterotoxin serum were present in both the cell extract and in extracted spore protein from one type C strain. These distinct components differed in molecular weight.
Histamine release from human leukocytes when stimulated by Mycoplasma salivarium
Authors: Parkinson C F
Published: January 2020

Incubated mixtures of Mycoplasma salivarium and nonsensitized mixed leukocytes released histamine. Spectrophotofluorometric detection of histamine occurred at physiological temperature and pH independent of complement and specific antiserum.
Reactivity of mast cells to Mycoplasma salivarium
Authors: Parkinson C F
Published: January 2020

Mice were sensitized to Mycoplasma salivarium and then challenged with heterologous and homologous antigens. The number of degranulating tissue mast cells was used to assess the degree of local tissue hyperactivity after antigenic challenge. Significant differences existed between homologous and heterologous antigenic challenges.
Effect of Mycoplasma pneumoniae on poliovirus replication
Authors: Milligan W H , Fletcher R D
Published: January 2020

Results are presented which indicate that different species of mycoplasma may have varying effects on the replication of different viral types.
Biological characterization of Fusobacterium necrophorum. Cell fractions in preparation for toxin and immunization studies
Authors: Garcia M M , Alexander D C , McKay K A
Published: January 2020

Fusobacterium necrophorum isolated from bovine liver abscesses was grown in bulk at 37 C for 24 h under a strict anaerobic atmosphere. Harvested washed cells were disrupted ultrasonically and fractionated by differential centrifugation into the intracellular (cytoplasm) and cell wall fractions. Both intact cells and cell fractions induced generalized cytopathic effect on primary pig kidney cultures and caused a variety of signs of illness and/or death of intraperitoneally injected mice. The intact cells, disrupted cells, and cell walls produced necrotic lesions and erythema on intradermally injected guinea pigs and rabbits, whereas the cytoplasm mainly erythema. By contrast, the used culture medium (culture filtrate) of F. necrophorum did not show any detectable toxicity. The toxic component of the cytoplasm appears to be associated with nondialyzable, hemolytic, high-molecular-weight proteins and its toxicity is reduced by trypsin and pronase. Heating at 60 C for 10 min decreased markedly its erythemal and cytotoxic ability, wheras the toxicity of the cell walls appeared to be only slightly affected even when heated at 100 C for 1 h. These results suggest that at leasttwo distinct cell-bound toxic factors are present in F. necrophorum cells.
Neutralization of Chlamydia trachomatis in cell culture
Authors: Howard L V
Published: January 2020

Neutralization of Chlamydia trachomatis was assayed by the decrease in inclusion-forming units in baby hamster kidney cells grown in culture. Five percent fresh guinea pig sera increased neutralization titers of rabbit antisera 100- to 1,000-fold but had no effect when normal rabbit sera were tested. Neutralization of a type A or B trachoma isolate was strain specific. Neutralization by human eye secretions and sera also was demonstrated when guinea pig sera were included in the test. All of the six human sera tested showed strain specificity against types A or B, in agreement with typing by the fluorescent antibody technique.
Inhibition of streptococcal attachment to receptors on human buccal epithelial cells by antigenically similar salivary glycoproteins
Authors: Williams R C , Gibbons R J
Published: January 2020

Preparations of salivary glycoproteins inhibited the attachment of certain indigenous oral streptococci to human buccal epithelial cells and fostered the desorption of previously attached bacteria. The adherence-inhibiting and desorptive activities of the glycoproteins correlated with their ability to aggregate these organisms. Pretreatment of glycoprotein preparations with certain blood group antisera impaired their adherence-inhibiting effect, suggesting that components with blood group substance reactivity were involved. Pretreatment of buccal epithelial cells with certain blood group antisera or concanavalin A masked the receptors associated with the attachment of Streptococcus sanguis SG1. The association of blood-group-reactive substances with the receptors involved in bacterial attachment may provide a basis for understanding the distinct specificities that bacteria exhibit for attaching to different tissues, organs, and hosts. Antiserum raised in rabbits to human epithelial cells also exhibited receptor-masking activity, and absorption of this serum with homologous salivary glycoproteins removed the antibodies responsible. These observations indicate that some salivary glycoproteins are antigenically similar to components on the epithelial cell surfaces they bathe. It is suggested that by mimicking the receptors present on epithelial cells, the mucinous glycoproteins of secretions may competitively inhibit the sorption of infectious agents and facilitate their removal after they are attached. These activities help to explain how mucinous glycoproteins augment the cleansing action of secretions.
Predominant cultivable flora isolated from human root surface caries plaque
Authors: Syed S A , Loesche W J , Pape H L , grenier E
Published: January 2020

Plaque samples were obtained from tooth surfaces exhibiting typical lesions of root surface caries and were immediately cultured by a continuous anaerobic procedure. The bacterial composition of root caries flora was determined on individual samples. Representative isolates from each specimen were characterized by morphological and physiological criteria. In addition, fluorescent antibody reagents were used to confirm the identification of Streptococcus mutans and Actinomyces viscosus. The plaque samples could be divided into two groups on the basis of the presence or absence of S. mutans in the plaque. In group I plaques, S. mutans comprised 30 percent of the total cultivable flora. S. sanguis was either not found or was present in very low number. In group II plaques, S. mutans was not detected, and S. sanguis formed 48 percent of the total plaque flora. A. viscosus was the dominant organism in all plaque samples, accounting for 47 percent of the group I isolates and 41 percent of the group II isolates.
Bovine parainfluenza type 3 virus infection: ultrastructural aspects of viral pathogenesis in the bovine respiratory tract
Authors: Tsai K S , Thomson R G
Published: January 2020

After aerosolization of a bovine strain of parainfluenza type 3 virus, the pathogenesis of the virus was followed from the trachea to the bronchioalveolar compartments of the lung of colostrum-free calves and of conventionally reared calves during a 5- to 12-day postexposure interval. By tissue titration, plaque assay, and electron microscopy, it was found that virus infection could be established in colostrum-free calves as well as in conventionally reared calves, even though sequential changes of virus replication were observed mainly in the infected colostrum-free calves during the 5- to 6-day postexposure periods. Electron microscopy demonstrations of (i) aggregates of viral nucleocapsids in the cytoplasm, (ii) alterations of cilia and basal bodies, (iii) dissolution of cytoplasmic membranes, and (iv) the shedding of virus into luminal spaces confirmed that epithelial cells of the respiratory tract were the primary target cells for the virus replication leading to cell destruction. These observations revealed further that productive infection was more efficient in the bronchioalveolar regions than in the tracheal regions, although large aggregates of viral nucleocapsids and destructive changes were more pronounced in the tracheal epithelium. The finding that parainfluenza type 3 virus replicates in the alveolar type II cells suggests that changes in surfactant production may occur during the peak of infection of these cells. The demonstration of virus budding through the basement membrane of small bronchioles and the presence of virus particles in the interstitial regions imply that one of the host defense lines, the basement membrane, may be impaired by virus invasion.
Persistence of rubellavirus-specific immunoglobulin M and immunoglobulin A antibodies: investigation of successive serum samples with lowered immunoglobulin G concentration
Authors: Hornsleth A , Leerhoy J , Grauballe P , Spanggaard H
Published: January 2020

The persistence of rubellavirus-specific immunoglobulin (Ig) M and IgA antibodies has been studied in seven patients with primary postnatal rubella infections. Successive blood samples obtained over a period of several years after the onset of disease have been investigated, employing the fluorescent antibody technique and the sucrose gradient centrifugation method. IgM antibodies were found to persist for 4 to 5 weeks after the onset of disease, with only moderate variation being observed with respect to the different patients and the method of investigation being studied. The persistence of IgA antibodies (as examined by the fluorescent antibody technique) varied from a few weeks to several years after the onset of the disease. The detection of IgA antibodies cannot be considered as conclusive for the diagnosis of recent rubella infections.
Immunodepression by Rowson-Parr virus in mice: effect of Rowson-Parr virus and Friend leukemia complex infections on background antibody-forming cells to various erythrocytes
Authors: Bendinelli M , Toniolo A , Campa M
Published: January 2020

The numbers of background antibody-forming cells (BPFC) toward erythrocytes of various species present in the lymphoid organs of unimmunized susceptible BALB/c and resistant C57BL/6 mice were investigated at various times after infection with Friend leukemia complex (FLC) or Rowson-Parr virus (RPV). Both virus preparations induced an increase of BPFC numbers in both animal strains, but the rate and magnitude of the enhancements produced by RPV were much lower. The degree of potentiation varied with the specificity of the BPFC populations and was more pronounced in the spleen than in the lymph nodes and in BALB/c than in C57BL/6 mice. In the late stage of FLC infection, the numbers of splenic BPFC to some erythrocytes underwent a dramatic fall, which was not observed in RPV-infected mice. BPFC present in BALB/c splenocytes cultured in diffusion chambers implanted in the peritoneal cavity of isogeneic normal mice were not affected by viral infection of the chambers.
Effects of canine distemper virus infection on lymphoid function in vitro and in vivo
Authors: Krakowka S , Cockerell G , Koestner A
Published: January 2020

In the present study, the immunodepressive effects of canine distemper virus (CDV) infection of dogs on two parameters of lymphocyte function, namely phytomitogen-induced cellular proliferation and skin allograft rejection, were investigated. Infection of susceptible gnotobiotic dogs with virulent R252-CDV resulted in a depression of peripheral blood lymphocyte mitogen response as measured by (3H)thymidine incorporation for up to 10 weeks after inoculation. This effect coincided with the appearance of viral antigen by immunofluorescence in leukocytes but persisted after the virus was no longer detectable. Loss of mitogen reactivity was seen in all infected dogs. However, when these same CDV-infected dogs were challenged with foreign skin allografts, no significant retention of grafts over controls was observed despite the depressed lymphocyte activity. Considering the in vitro and in vivo data it was concluded that, although immunodepressive effects of CDV were demonstrated in vitro, paralled in vivo experiments indicated that less than complete suppression of immune functions occurs during the course of CDV infection.
Growth of Mycobacterium marinum in the footpads of T-cell-depleted mice
Authors: Collins F M , Montalbine V , Morrison N E
Published: January 2020

Mycobacterium marinum strains 1218 and 1219 were inoculated into the hind footpads of T-cell-depleted specific pathogen-free C57B1/6 mice, and the growth and survival of the organisms at the site of injection, the draining popliteal lymph node, and the spleen and lung were quantitated for up to 70 days. T-cell depletion largely ablated the normal cell-mediated antituberculous response to the M. marinum population. The mice were able to control the further growth of the inoculum within the footpad only after it had reached 5 to 10 times that present in the normal controls. The high temperature-adapted strain (37 C; strain no. 1218) induced an increasing infection in the liver, spleen, and lungs of the THXB mice, and the infection eventually spread to the opposite footpad and to the tail skin. Strain 1219 gave rise to considerable systemic involvement in the THXB host despite its inability to survive at 37 C, but the size of the splenic and lung populations was considerably lower than in the 1218-infected animals. Both M. marinum infections persisted in the tissues of the T-cell-depleted mice with no indication of a cell-mediated immune response. Footpad swelling in the M. marinum-infected mice was not greatly reduced by T-cell depletion, and, if anything, tended to persist at high levels long after the swelling of the control feet had gone into a decline. On the other hand, incorporation of tritiated thymidine by cells within the infected footpads, the draining lymph node, and the spleen was considerably reduced in the T-cell-depleted host compared with control values. Late in the infection, there was a significant increase in the amount of label taken up by the cells in the footpads of the T-cell-depleted host.
Superinfection in mice previously infected with Mycobacterium leprae
Authors: Levy L
Published: January 2020

Previous studies of the protection of mice by prior infection with Mycobacterium leprae in one hind footpad against challenge with M.leprae in the opposite hind footpad had produced conflicting results; therefore, the problem was restudied. In several experiments, BALB/c mice were inoculated first in the right hind footpad with 5,000 M. leprae and then challenged in the left hind footpad with 5,000 M. leprae of the same strain at intervals after primary infection, at the same time that uninfected mice were inoculated. Multiplication of the M. leprae of the secondary challenge inoculum occurred at the same rate and to the same level as multiplication in uninfected mice when challenges were made soon after primary infection. Multiplication was slowed but proceeded to the same level in previously infected as in uninfected mice when the challenges were administered between 76 and 106 days after primary infection (47 to 17 days before the M. leprae of the primary inoculum had multiplied to the level of 10-6 organisms per footpad). Finally, the M. leprae of a secondary challenge administered at the time that the organisms of the primary inoculum had multiplied to 10-6 per footpad or later not only multiplied more slowly in previously infected than in control animals, but multiplication in the previously infected animals reached a lower maximum. These results are similar to those observed when mice previously infected with M. bovis (BCG), M. marinum, Toxoplasma gondii, or Besnoitia jellisoni were challenged with M. leprae.
Alterations in mouse macrophage migration: a function of assay systems, lymphocyte activation product preparation, and fractionation
Authors: Sandok P L , Hinsdill R D , Albrecht R M
Published: January 2020

Supernatants from mouse spleen cell and peritoneal cell cultures were tested for the presence of lymphocyte activation products. Supernatants from mouse spleen cell and peritoneal cell cultures incubated with brucella antigens contained a macrophage migration inhibition factor(s) and a macrophage spreading factor(s) only if the cells were harvested from Brucella-infected mice. After dialysis and freeze-drying, the supernatants were fractionated by preparative acrylamide-gel electrophoresis. Three fractions with lymphocyte activation product activity were obtained from the fractionated supernatants of mouse spleen cells and peritoneal cells harvested from Brucella-infected mice and cultured with brucella antigen. One fraction inhibited mouse macrophage migration from capillary tubes but not from agarose wells. A second fraction not only inhibited macrophage migration from both agarose wells and capillary tubes, but also contained an activity(s) that stimulated macrophage migration through Nuclepore filters and induced macrophage spreading. A third fraction timulated macrophage migration from agarose wells and also contained an activity(s) that stimulated macrophage migration through Nuclepore filters. Fractionated supernatants of mouse spleen cells and peritoneal cells harvested from uninfected mice incubated with and without brucella antigen, as well as of cells harvested from infected mice and not incubated with antigen, did not contain detectable lymphocyte activation products.
Effect of administered human interferon on experimental rabies in monkeys
Authors: Hilfenhaus J , Karges H E , Weinmann E , Barth R
Published: January 2020

Cynomolgus monkeys infected with rabies virus were protected by repeated intramuscular administration of human leukocyte interferon beginning 24 h after infection.
Cross-protection among feline caliciviruses
Authors: Povey C , Ingersoll J
Published: January 2020

Each of five groups of specific-pathogen-free and conventionally reared cats was infected with a different strain of feline calicivirus. Two of the strains were pathogenic, producing characteristically fever, depression, loss of appetite, buccal ulceration, and occasionally increased ocular and nasal secretion. Two of the other strains were midly pathogenic and associated with fever or buccal ulceration or both; the fifth strain was nonpathogenic. The two pathogenic strains plus three others shown also to be pathogenic were used 3 months after the initial infection to challenge the cats in rearranged groupings. Of the 28 conventional cats challenged six (21.4%) showed at least a febrile response, although none of the 30 specific-pathogen-free cats showed any clinical signs. After challenge, virus was recovered from throat swabs of 37 or the 58 cats (63.8%) including the six which showed symptoms, but the duration of the excretion of virus was significantly less than that seen with the initial infection. The homologous and heterotypic antibody responses correlated well with the clinical protection, or lack of it, seen on challenge. The results provide further evidence for significant cross-relationships between feline caliciviruses.
Effect of cyclophosphamide on infections in mice caused by virulent and avirulent strains of influenza virus
Authors: Hurd J , Heath R B
Published: January 2020

Induced immunosuppression with the drug cyclophosphamide was shown to convert the relatively harmless infection with an avirulent strain of Kunz influenza virus into a fatal pneumonic illness. The drug was also shown to increase the mortality of mice infected with low concentrations of a virulent variant of this strain, but it delayed the time of death of mice that were infected with high concentrations ofthe same variant. The probable roles of immune and inflammatory mechanisms in recovery from primary influenza virus infections are discussed.
Motility as a virulence factor for Vibrio cholerae
Authors: Guentzel M N , Berry L J
Published: January 2020

The ability of motile strains of the Ogawa and Inaba serotypes of classical Vibrio cholerae and of the El Tor biotypes to kill suckling mice after oral challenge with 10-8 colony-forming units (representing at least 100 to 1,000 minimal lethal doses) was compared to that of nonmotile derivatives of the same strains. Loss of motility, in each case, resulted in a marked reduction in virulence. The mortality (at 36 h) caused by 10 of the 13 nonmotile strains was 32% or less. whereas the motile wild-type strains resulted in nearly 100% deaths. The reduced virulence of the nonmotile strains was associated with reduced capacity to adsorb to the surface of segments of mouse intestine. The mutants were tested for alterations in enterotoxin production and surface properties. The results suggest that motility may contribute to virulence by increasing the chance for association of the vibrios with the intestinal mucosa.
Requirement for a bone marrow-derived component in the expression of cell-mediated antibacterial immunity
Authors: Hahn H
Published: January 2020

Mice were X irradiated with 400 R and 1 week post-irradiation were found to be unable to develop antilisterial immunity after active or passive immunization with immunologically committed spleen lymphocytes from Listeria-immune donors. This consequence of irradiation disappeared spontaneously within 21 days of exposure to X rays. Mice irradiated with as much as 900 R could be passively protected by immunologically committed lymphoid cells from Listeria-immune donors 10 days after irradiation if they had been given normal bone marrow cells on the day or irradiation. It is concluded that, in addition to immunologically committed lymphocytes, a second cellular component is needed for the expression of antibacterial immunity. This second component is bone marrow derived.
Association of
Streptococcus mutans
with Human Dental Decay
Authors: Loesche W. J. , Rowan J. , Straffon L. H. , Loos P. J.
Published: January 2020

The association of
Streptococcus mutans
with human dental decay was investigated by using several types of samples: (i) paraffin-stimulated saliva samples taken from children with from 0 to 15 decayed teeth; (ii) pooled occlusal and approximal plaque taken from children with no decayed or filled teeth, or from children with rampant caries of 10 or more teeth; (iii) plaque removed from single occlusal fissures that were either carious or noncarious. The results showed a significant association between plaque levels of
S. mutans
and caries. The strongest association,
P
< 0.0001, was found when plaque was removed from single occlusal fissures. Seventy-one percent of the carious fissures had
S. mutans
accounting for more than 10% of the viable flora, whereas 70% of the fissures that were caries free had no detectable
S. mutans
. Sixty-five percent of the pooled plaque samples from the children with rampant caries had
S. mutans
accounting for more than 10% of the viable flora, whereas 40% of the pooled samples from children that were caries free had no detectable
S. mutans
. Saliva samples tended to have low levels of
S. mutans
and were equivocal in demonstrating a relationship between
S. mutans
and caries.
Effect of Trace Metals on Phagocytosis by Alveolar Macrophages
Authors: Graham Judith A. , Gardner Donald E. , Waters Michael D. , Coffin David L.
Published: January 2020

Experiments were performed to measure the effect of trace metals on a vital function of the alveolar macrophage (AM), phagocytosis. Since certain trace metals were found to reduce the viability of AMs, a technique was developed to permit examination of live cells only for phagocytosis. Evidence is presented that Ni
2+
selectively altered the phagocytic activity of AMs at concentrations lower than those which caused cell death. It is further shown that a level of VO
3
−
that caused extensive lysis and death did not reduce phagocytosis in surviving cells. The effects of Cd
2+
, Cr
3+
, and Mn
2+
on AMs were also examined.
Characterization of a Non-Type-Specific Antigen(s) Associated with Group A Streptococcal Type 12 M Protein
Authors: Vosti Kenneth L.
Published: January 2020

The sharing of one and possibly two or more non-type-specific antigens by most strains of groups A, C, and G streptococci is described. With the exception of a single strain of
Proteus mirabilis
, this antigen(s) was not found among strains of groups B and D streptococci, coagulase-positive staphylococci,
Escherichia coli, Pseudomonas
sp., and
Salmonella
sp. The non-type-specific antigen(s) could not be separated from M protein by fractionation with various saturations of ammonium sulfate or by column chromatography with calcium hydroxylapatite even though the latter method allowed the recovery of a fraction of M protein which was free of the cross-reactive antigen(s). The resistance of this non-type-specific antigen(s) to hot acid extraction and its sensitivity to treatment with trypsin differentiate it from the T and R antigens of group A streptococci, both of which are trypsin resistant. Co-precipitation of both type-and non-type-specific antigens occurred with type-specific antiserum and suggested that the type- and non-type-specific antigens represent either different, covalently bonded antigenic determinants on the same protein or different proteins noncovalently linked together.