bluuebunny/crossref_metadata_2025_split huggingface dataset:
Danazol influences gonadotropin secretion acting at the hypothalamic level
Authors: Panidis D. , Vavilis D. , Rousso D. , Stergiopoulos K. , Kalogeropoulos A. 
Published: May 2004

AbstractOBJECTIVES: The purpose of the study was to determine the influence of danazol on gonadotropin secretion. METHODS: Ten endometriotic patients were treated with danazol for 6 months. To evaluate gonadotropin and estradiol secretion, a gonadotropin‐releasing hormone (GnRH) test and a clomiphene citrate (CC) challenge test were carried out in the follicular phase before treatment, during the sixth month of treatment and after the reappearance of the second menses. The same tests were also performed, only once, in the follicular phase of ten normal women. RESULTS: GnRH‐stimulated gonadotropin response during danazol treatment was significantly higher than that in the same group of women before and after danazol treatment, as well as in controls. Gonadotropin increase after clomiphene citrate administration during danazol treatment was not significant; moreover, LH response was significantly lower than that in the same group of patients before and after danazol treatment, as well as in controls. CONCLUSIONS: Our results suggest that danazol exerts a suppressive effect on gonadotropin secretion acting at the hypothalamic level.
Endocrine profile of women with amenorrhea and oligomenorrhea
Authors: Seshadri L. , John S. , George S.S. , Seshadri M.S. 
Published: May 2004

AbstractOBJECTIVES: To find out the common causes of amenorrhea and oligomenorrhea in south Indian women and to draw up a protocol for evaluation of women with these problems. METHODS: A retrospective study of 426 women with amenorrhea and oligomenorrhea was carried out. RESULTS: Forty‐one patients had primary amenorrhea, 132 had secondary amenorrhea and 289 women presented with oligomenorrhea. Hypergonadotropic amenorrhea and congenital absence of the uterus and vagina accounted for 60% of primary amenorrhea. Chronic anovulatory disorders and premature ovarian failure were found in 72% of women with secondary amenorrhea but weight loss related amenorrhea was uncommon. CONCLUSIONS: On the basis of the observations made, a protocol for evaluation and management of women with amenorrhea and oligomenorrhea was evolved.
A time and cost analysis of the management of incomplete abortion with manual vacuum aspiration
Authors: Blumenthal P.D. , Remsburg R.E. 
Published: May 2004

AbstractOBJECTIVES: Traditionally, management of incomplete abortion involves use of D&C or suction curettage in the operating room. Such management is costly and time‐consuming. In order to potentially save time and money, we studied the use of manual vacuum aspiration curettage (MVAC) for the management of this problem. METHODS: Data on hospital charges and times (e.g. waiting time, procedure time) were obtained for all cases of incomplete abortion presenting to hospital between January 1990 and July 1992. Between January 1990 and July 1991, all cases were managed traditionally. After July 1991, all cases were managed using MVAC in either the emergency room or the labor ward. RESULTS: Compared to the use of electrical suction equipment in the operating theatre, MVAC procedures resulted in significant savings in terms of both waiting times and costs. Waiting time was reduced by 52% and procedure time was reduced from a mean of 33 min to 19 min (P < 0.01). Total hospital costs were reduced by 41% (P < 0.01). CONCLUSIONS: Use of manual vacuum aspiration curettage in the management of incomplete abortion can reduce hospital costs and save time for both patients and clinicians.
Dimensions of informed consent to treatment
Authors: Dickens B.M. , Cook R.J. 
Published: May 2004

AbstractModern law approaches patients’ consent to treatment not only through liability for unauthorized touching, namely criminal assault and/or civil (non‐criminal) battery, but also through liability for negligence. Physicians must exercise appropriate skill in conducting procedures, and in providing patients with information material to the choices that patients have to make. The doctrine of informed consent serves the ethical goal of respecting patients’ rights of self‐determination. Information is initially pitched at the reasonable, prudent person in the patient's circumstances, and then fine‐tuned to what is actually known about the particular patient's needs for information. Elements to be disclosed include the patient's prognosis if untreated, alternative treatment goals and options, the success rate of each option, and its known effects and material risks. Risks include medical risks, but also risks to general well‐being such as economic and similar reasonable interests. Consent is a continuing process, not an event or signed form.
ELECTRON DENSITOMETRY OF STAINED VIRUS PARTICLES
Authors: Hall Cecil E. 
Published: May 2004

Methods are described for determining the relative mass of particles in electron microscope specimens through the measurement of photographic densities in recorded images. These methods were applied to a quantitative study of the amounts of electron stains that could be associated with the particles of tomato bushy stunt virus (BSV) and tobacco mosaic virus (TMV). In the pH range above 2 where the viruses are stable, the amount of stain absorbed is too small to produce adequate contrast in the electron microscope. Maximum stain absorption was achieved at pH about 1 where with several reagents and combinations of reagents the mass of BSV could be increased to about four times that of the unstained particles. Optimum results were obtained with phosphotungstic acid alone or in combination with Pt, Th, or La ions. Since the pH conditions for high stain absorption are normally destructive, morphology is satisfactorily preserved only when the phosphotungstic acid is applied in concentrations of 10 per cent or greater or when the use of destructive reagents is preceded by a preliminary fixation under mild conditions. Maximum staining of TMV increased the mass of the particles to about two times that of the unstained.
Estimates of the mass of heavily stained BSV particles indicate that their density is 3.3 gm./cm.3 The high internal hydration of BSV probably accounts for the greater stain absorption and penetration compared to those of TMV which has very low or zero internal hydration.
Anomalous images resulting from the use of electron stains are shown and discussed.
A MICROPHOTOMETRIC STUDY OF THE SYNTHESES OF DESOXYRIBONUCLEIC ACID AND NUCLEAR HISTONE
Authors: Bloch David P. , Godman Gabriel C. 
Published: May 2004

1. The fast green stain of Alfert and Geschwind for nuclear basic protein is shown to obey the Beer-Lambert laws when used on purified histone. Interference from acid substances other than nucleic acids as a possible source of error is indicated.
2. Use of this technique after a modified Feulgen stain enables determination of relative amounts of desoxyribonucleic acid and histone in the same individual cells.
3. DNA and histone are shown to have the same distribution in formalin-fixed nuclei.
4. The syntheses of DNA and histone proceed simultaneously resulting in the doubling of both these substances prior to cell division.
5. The standard error for histone values is greater than that for DNA; however, the source of this variability is not known.
A SMALL PARTICULATE COMPONENT OF THE CYTOPLASM
Authors: Palade George E. 
Published: May 2004

A particulate component of small dimensions (100 to 150 A) and high density is described in the ground substance of the cytoplasm of mammalian and avian cells.
In many cell types that seem to have in common a high degree of differentiation, the new component is preferentially associated with the membrane of the endoplasmic reticulum; whereas in other cell types, characterized by rapid proliferation, it occurs more or less freely distributed in the ground substance of the cytoplasm.
In the Discussion an attempt is made to integrate the observations presented in this paper with the already available cytological, histochemical, and cytochemical information.
THE FINE STRUCTURE OF NEURONS
Authors: Palay Sanford L. , Palade George E. 
Published: May 2004

1. Thin sections of representative neurons from intramural, sympathetic and dorsal root ganglia, medulla oblongata, and cerebellar cortex were studied with the aid of the electron microscope.
2. The Nissl substance of these neurons consists of masses of endoplasmic reticulum showing various degrees of orientation; upon and between the cisternae, tubules, and vesicles of the reticulum lie clusters of punctate granules, 10 to 30 mµ in diameter.
3. A second system of membranes can be distinguished from the endoplasmic reticulum of the Nissl bodies by shallower and more tightly packed cisternae and by absence of granules. Intermediate forms between the two membranous systems have been found.
4. The cytoplasm between Nissl bodies contains numerous mitochondria, rounded lipid inclusions, and fine filaments.
THE USE OF SILVER NITRATE AS A VITAL STAIN, AND ITS DISTRIBUTION IN SEVERAL MAMMALIAN TISSUES AS STUDIED WITH THE ELECTRON MICROSCOPE
Authors: Dempsey Edward W. , Wislocki George B. 
Published: May 2004

After chronic administration of a dilute solution of silver nitrate in drinking water to rats, mice, and guinea pigs, granular deposits of metallic silver were detected in electron micrographs of the kidney, liver, thyroid, and pancreas. The silver deposits were in the form of extremely dense, angular particles with sharp outlines. They varied from aggregates a few microns in diameter down to granules at the limit of resolution of the electron microscope.
The principal sites of deposition were (1) basement membranes, especially those of the renal glomeruli, proximal convoluted tubules, and various glands, and those associated with vascular endothelium, and (2) the cytoplasm of fixed and free macrophages. Both in Kupffer cells lining hepatic sinusoids and in the wandering macrophages of other tissues, the silver was segregated in discrete vacuoles. In addition, granular deposits were observed in occasional vesicular structures in the proximal convoluted tubules of the kidney, the hepatic cells, and the pancreatic acinar cell. These structures, in favorable preparations, contained an outer double layered membrane and internal folds similar to those of mitochondria, from which they appear to have been derived. The significance of these findings in heavy metal poisoning and in cellular physiology is briefly discussed.
FACTORS INFLUENCING THE ABILITY OF ISOLATED CELL NUCLEI TO FORM GELS IN DILUTE ALKALI
Authors: Dounce Alexander L. , Monty Kenneth J. 
Published: May 2004

1. Known methods for isolating cell nuclei are divided into two classes, depending on whether or not the nuclei are capable of forming gels in dilute alkali or strong saline solutions. Methods which produce nuclei that can form gels apparently prevent the action of an intramitochondrial enzyme capable of destroying the gel-forming capacity of the nuclei. Methods in the other class are believed to permit this enzyme to act on the nuclei during the isolation procedure, causing detachment of DNA from some nuclear constituent (probably protein).
2. It is shown that heating in alkaline solution and x-irradiation can destroy nuclear gels. Heating in acid or neutral solutions can destroy the capacity of isolated nuclei to form gels.
3. Chemical and biological evidence is summarized in favor of the hypothesis that DNA is normally bound firmly to some nuclear component by non-ionic linkages.
SEDIMENTATION AND VISCOSITY STUDIES ON THE CAPSULAR AND SOMATIC POLYSACCHARIDES OF PNEUMOCOCCUS TYPE III
Authors: Koenig Virgil L. , Perrings J. D. 
Published: May 2004

Sedimentation constants at infinite dilution have been found to be 1.89 and 4.06 for the somatic and capsular polysaccharides, respectively, from pneumococcus Type III.
Intrinsic viscosities have been determined for the somatic and capsular polysaccharides of pneumococcus Type III using the Ostwald viscometer.
Molecular weights and dimensions have been calculated for the somatic and capsular polysaccharides of pneumococcus Type III assuming the molecules to be prolate ellipsoids of revolution. Values for the somatic polysaccharide are: molecular weight, 26,400; diameter, 0.97 mµ; and length, 36.18 mµ. Values for the capsular polysaccharide are: molecular weight, 171,800; diameter, 1.04 mµ; and length, 177.87 mµ.
The molecular weights were calculated for the somatic and capsular polysaccharides of pneumococcus Type III assuming the molecules to be flexible chains. The value of the molecular weight of the somatic polysaccharide is 31,500 and the value for the molecular weight of the capsular polysaccharide is 267,500.
The molecules of both the somatic and capsular polysaccharides exhibit high degrees of asymmetry.
ELECTRON MICROSCOPE STUDIES ON THE CELLS OF THE MALPIGHIAN TUBULES OF THE GRASSHOPPER (ORTHOPTERA, ACRIDIDAE)
Authors: Beams H. W. , Tahmisian T. N. , Devine R. L. 
Published: May 2004

For purposes of description, the cells of the Malpighian tubules of the grasshopper may be divided into basal, intermediate, and apical zones.
The basal zone of the cell contains what appears to be an elaborate infolding of the cell membrane at the base. This condition results in the basal cell cytoplasm being divided into many compartments. The compartments contain mitochondria that are often arranged in rows. Other small bodies which possess relatively dense outer borders and less dense cores were observed within the compartments. These bodies are unidentified.
The brush border of the apical zone contains a multitude of vertically arranged protoplasmic processes. Stages were found which suggest that the filamentous mitochondria migrate from the cell body to the base of the protoplasmic processes, where they enter them and move apically. Some of the mitochondria were observed at the very tips of the processes where they enlarge producing an accompanying bulging of the tips. This condition is interpreted as a stage in the pinching off of the mitochondria-laden tips of the protoplasmic processes.
OPTICAL ROTATION AND HELICAL POLYPEPTIDE CHAIN CONFIGURATION IN COLLAGEN AND GELATIN
Authors: Cohen Carolyn 
Published: May 2004

The optical rotation phenomena exhibited by a citrate-extracted fraction of ichthyocol (from carp swim bladder), as well as by the parent gelatin derived therefrom, have been studied. Dispersion data for all cases follow a single-term Drude equation, but the variations with state are adequately expressed by simple reference to changes in [α]D as follows:—
1. The native collagen fraction, dispersed in 0.15 M citrate buffer at pH 3.7 in the cold (11°C.), yields a high negative specific rotation, [α]D, near –350°.
2. During equilibration at 40°C., which causes conversion to a monodisperse parent gelatin, the rotation drops to about –110°.
3. Gelation at 2°C. results in a partial regain of rotation to around –290°. This mutarotation is reversible, depending on temperature.
4. In the range 0.02 to 0.28 per cent the native ichthyocol and the warm gelatin solutions show little concentration dependence, but with the cold gelatin solutions the specific rotation increases with concentration. Gelatin films formed by cold evaporation yield high specific rotation (ca. –620°), but those formed by hot evaporation retain low optical activity.
5. Since this same collagen-gelatin system has been investigated physicochemically, it is possible to relate molecular changes to the observed variations in optical rotation. Conclusions are similar to those of Robinson (1953), who studied other gelatins: high negative rotation is believed related to a native collagen polypeptide configuration, herein specified as helical (from x-ray diffraction considerations) and destroyed by heating. The possible roles of intermolecular interactions and of prevalent pyrrolidine constituents in influencing the helical configuration and optical activity are discussed.
TWO PROTEINS PURIFIED FROM LOBSTER NERVE EXTRACT
Authors: Maxfield Myles , Hartley Robert W. 
Published: May 2004

1. A protein component, fraction B, of lobster nerve extracts has been isolated and purified by differential ultracentrifugation and precipitation with zinc acetate.
2. Physicochemical data obtained from this protein and from fraction C are summarized.
3. Fraction B is present in lobster nerve extracts in higher concentration (relative to fraction A) than in blood.
4. A second component, fraction C, of sedimentation constant S20o = 13.2 has been isolated from lobster nerve extracts.
STUDIES ON THE FINE STRUCTURE OF THE MAMMALIAN TESTIS
Authors: Burgos Mario H. , Fawcett Don W. 
Published: May 2004

The differentiation of cat spermatids was studied in thin sections examined with the electron microscope. The Golgi complex of the spermatid consists of a central aggregation of minute vacuoles, partially surrounded by a lamellar arrangement of flattened vesicles. In the formation of the acrosome, one or more moderately dense homogeneous granules arise within vacuoles of the Golgi complex. The coalescence of these vacuoles and their contained granules gives rise to a single acrosomal granule within a sizable membrane-limited vacuole, termed the acrosomal vesicle. This adheres to the nuclear membrane and later becomes closely applied to the anterior two-thirds of the elongating nucleus to form a closed bilaminar head cap. The substance of the acrosomal granule occupies the narrow cleft between the membranous layers of the cap.
The caudal sheath is comprised of many straight filaments extending backward from a ring which encircles the nucleus at the posterior margin of the head cap.
Attention is directed to the frequent occurrence of pairs of spermatids joined by a protoplasmic bridge and the origin and possible significance of this relationship are discussed.
INTERPRETATIONS OF ELECTRON MICROGRAPHS OF SINGLE AND SERIAL SECTIONS
Authors: Williams Robley C. , Kallman Frances 
Published: May 2004

A method of securing serial sections for electron microscopy is described. Serial sections present certain anomalies of interpretation of a nature such that a complete and detailed three-dimensional reconstruction of the sectioned tissue cannot be made. These anomalies are discussed, as well as those which have been encountered in the interpretation of single sections. Observations of the following kinds have been made in an attempt to elucidate the interpretation of single and serial sections: differing methods of mounting adjacent sections, observation of the same section by high-angle stereoscopy, and examination of sections which have been shadowed prior to and subsequent to electron microscopy.
It is found that the appearance of sections is independent of the choice of side to be placed against the formvar films. Stereoscopy shows that the appearance of fine structures is strongly dependent upon the direction of the penetrating electron beam with respect to the plane of the structures. Stereoscopy, combined with shadowing, shows quantitatively that extensive sublimation of polymer occurs upon normal exposure in the electron microscope. Observation of sections shadowed prior to electron microscopy indicates that varying amounts of material are removed between sections by the action of microtomy; i.e., it is probable that the sum of the thicknesses of several serial sections is considerably less than the total thickness of material removed from the block. It is believed that this effect, combined with the effect of sublimation, aids in explaining the failure of adjacent sections to exhibit continuity in their detailed structures.
STUDIES OF TWO TYPES OF ALKALINE PHOSPHATASE IN NUCLEI ISOLATED FROM THE LIVERS OF FED AND FASTED RATS BY A MODIFICATION OF THE BEHRENS TECHNIQUE
Authors: Emery Arthur J. , Dounce Alexander L. 
Published: May 2004

1. Rat liver nuclei were isolated from normal rats and rats fasted for 36 hours by a slight modification of the Behrens technique.
2. The nucleus of the rat liver cell contains two types of alkaline phosphatase. This confirms the previous findings on rat liver nuclei isolated in aqueous media.
3. The one type of alkaline phosphatase is not activated by magnesium ions, and this enzyme is very strongly bound to structural material of the nucleus. The other type of alkaline phosphatase is activated by magnesium ions, and this enzyme is probably free to diffuse from cytoplasm to nucleus and vice versa through the nuclear membrane.
4. Fasting caused a pronounced decrease of protein in general and of the alkaline phosphatase which is activated by magnesium ions from the nucleus of the rat liver cell, while the alkaline phosphatase that is not activated by magnesium was less affected.
ON ARTIFACTS APPEARING IN THE HISTOCHEMICAL FIXATION OF GLYCOGEN
Authors: Takahashi Kohnosuke , Iwase Shoji 
Published: May 2004

1. Fixation artifacts associated with glycogen translocation are prevalent in tissues of parenchymatous type and scarce or non-existent in tissues of loose type.
2. Liver tissue treated with M/3 NaOH solution before fixation did not show an uneven distribution of glycogen. This was interpreted as indicating that the liver, a tissue of parenchymatous type, was changed, so to speak, into a loose type of tissue by alkali treatment.
3. The so called Alkohol-flucht of glycogen was produced in Yoshida's ascites tumor cells by a procedure which changed a loose type of tissue into a parenchymatous one, that is, by packing the tumor cells tightly.
4. The translocation of glycogen in cells appeared to occur when the fixatives penetrated the cells rapidly from a single direction, but failed to occur when the cells were attacked by the fixative from all directions.
5. In dried smears of Yoshida's ascites tumor cells and bone marrow cells, the glycogen particles are translocated to the peripheral regions of the cells, and coalesce there.
The production of these artifacts is related in some way to the physicochemical properties of the protoplasm and plasma membrane of the cells.
OBSERVATIONS ON THE FINE STRUCTURE OF THE MACRONUCLEUS OF TOKOPHRYA INFUSIONUM
Authors: Rudzinska Maria A. , Porter Keith R. 
Published: May 2004

The macronucleus in Tokophrya infusionum is composed of numerous Feulgen-positive chromatin bodies (about 0.5 µ in diameter) which appear in thin sections as a dense spongework, homogeneous throughout. The same appearance characterizes metaphase chromosomes of higher forms.
Some chromatin bodies of the macronucleus were found to possess a highly organized structure in certain old organisms. This structure appears in cross-sections as a honeycomb and in longitudinal sections as parallel lines about 120 A in diameter evenly spaced (about 230 A).
As far as is known this is the first time a regular structure has been found in bodies of chromosomal character at the dimensional level presently explored by electron microscopy. The demonstration that OsO4 can preserve order in chromatin material is another significant aspect of these findings.