bluuebunny/crossref_metadata_2025_split huggingface dataset:
HYPOPHYSE UND HORMONELLES CALCIUM-REGULATIONSSYSTEM
Authors: Salzer Georg M. 
Published: October 2009

ABSTRACT
A survey of the literature of the last fifty years relating to our topic indicates that the sentence from Copp (1969) »there is no evidence that the anterior pituitary or the central nervous system has any direct effect on the secretion of parathormone or calcitonin« is not based upon concrete experimental data. This is particularly evident from a morphological aspect, since considerable variations in the parathyroids have been repeately observed as the result of both hypophysectomy and the application of hypophyseal extracts. Experimental evidence has contributed little material relevant to a possible hypophyseal control of the parathyroids with the exception of the observation that after hypophysectomy the plasma calcium level remains unchanged.
Contrary to this, up to now no positive morphological changes in the C-cells of the thyroid have been determined, although experimental evidence suggests a certain hypophyseal control upon the secretion of calcitonin. All the results of our own experiments in parathyroid morphology suggest significant alterations in the glands subsequent to hypophysectomy. A histological survey shows a considerable reduction in the size of the entire organ and an increase in the connective tissue of the gland. Karyometric tests reveal a reduction of the small diameter of the nuclei of 13.5%, a quantity which corresponds to that found in the nuclei of the adrenal cortex and the follicular cells of the thyroid after the same operation. As a result of hypophysectomy it is possible under the electron microscope to distinguish alterations in the secretory structures of the parenchyma cells of the parathyroid that may indicate restricted parathormone synthesis.
In order to exclude the possibility that these changes may have been conditioned by a cessation of adrenal activity, the parathyroid morphology was analyzed also after adrenalectomy. The results obtained in this way differ fundamentally from those produced by hypophysectomy.
Morphometrical investigation of the C-cell population of the thyroid after hypophysectomy show a significant reduction in the size of the nuclei of 13.6 % and, under the electron microscope, a reduction of the cytoplasm as well as an increase in the number of calcitonin granula.
Two further test series have shown that in hypophysectomized but otherwise untreated animals the plasma calcium level is within the normal range. On the other hand the normal ability to counteract hyper- or hypocalcaemia was found to be lacking to a great extent.
All the results obtained suggest the existence of some hypophyseal influence upon the hormonal calcium regulation system.
A hypothesis is framed to the effect that the feedback: plasma calcium – parathormone and calcitonin serves, above all, the purpose of compensating an alimentary over- and under-supply of calcium, whereas the hypophyseal regulatory cycle serves to meet the endogenic calcium requirements of the organism under special circumstances, as for instance growth or lactation.
TECHNIQUES FOR THE ISOLATION OF CELLS OF THE ADRENAL CORTEX, THE ANTERIOR PITUITARY AND THE CORPUS LUTEUM: MORPHOLOGICAL AND FUNCTIONAL EVALUATION OF THE ISOLATED CELLS
Authors: Sayers George , Portanova Ronald , Beall Robert J. , Seelig Steven , Malamed Sasha 
Published: October 2009

ABSTRACT
A trypsin technique for the isolation of cells of the rat adrenal, the rat anterior pituitary and the bovine corpus luteum is described. The isolated cells have been characterized in morphological and functional terms.
AUTORADIOGRAPHIC TECHNIQUES FOR THE LOCALIZATION OF HORMONES AND DRUGS AT THE CELLULAR AND SUBCELLULAR LEVEL
Authors: Stumpf Walter E. 
Published: October 2009

ABSTRACT
The paper describes four autoradiographic techniques which can be recommended, not without restrictions, for the study of the cellular and subcellular hormone or drug distribution in tissues. In all of the techniques desiccated slides are used which are precoated with photographic emulsion. The techniques are (I) Dry-mounting of freeze-dried sections on emulsion precoated slides; (II) Thaw-mounting of frozen sections on emulsion precoated slides; (III) Smear-mounting on emulsion precoated slides; and (IV) Touch-mounting on emulsion precoated slides. The techniques are designed to avoid or minimize translocation of the labelled molecules during preparation and during the application to photographic emulsion. Cited examples of application of these techniques demonstrate their utility in hormone research.
EVALUATION OF TISSUE STEROID BINDING IN VITRO
Authors: Wira C. R. , Rochefort H. , Baulieu E. E. 
Published: October 2009

ABSTRACT
The definition of a RECEPTOR* in terms of a receptive site, an executive site and a coupling mechanism, is followed by a general consideration of four binding criteria, which include hormone specificity, tissue specificity, high affinity and saturation, essential for distinguishing between specific and nonspecific binding. Experimental approaches are proposed for choosing an experimental system (either organized or soluble) and detecting the presence of protein binding sites.
Techniques are then presented for evaluating the specific protein binding sites (receptors) in terms of the four criteria. This is followed by a brief consideration of how receptors may be located in cells and characterized when extracted.
Finally various examples of oestrogen, androgen, progestagen, glucocorticoid and mineralocorticoid binding to their respective target tissues are presented, to illustrate how researchers have identified specific corticoid and mineralocorticoid binding in their respective target tissue receptors.
ADRENALECTOMY IN CUSHING'S DISEASE
Authors: Ernest Ingrid , Ekman Hans 
Published: October 2009

SUMMARY
Forty-four patients with Cushing's disease underwent bilateral adrenalectomy and 39 survivors were followed for, on an average, eight years and a half. There were three postoperative deaths and two other patients died within one year after operation. Thirty patients are now working but six remain invalidized. In four subjects cortisol secretion persisted in spite of "total" adrenalectomy but a clinical remission ultimately occurred. Five patients, who presented with an atypical clinical picture, failed to show any obvious changes in the distribution of fat or in the complexion. Body weight did not decrease after surgery in several patients and in many others body weight increased again after an initial loss of weight. Menstruations reappeared in all premenopausal women except two. Manifest diabetes, which was found in seven subjects, disappeared and in several other cases glucose tolerance improved.
The blood pressure, which was high in most patients, normalized or decreased in all hypertensive patients but the blood pressure still remains elevated in 22 subjects. ECG-abnormalities disappeared in 11 of 17 subjects, who presented with ST-T changes and/or high amplitude R waves. The size of the heart decreased in most patients with cardiomegaly.
A remarkable improvement in the radiological appearance of the vertebrae occurred in a 16-year-old boy but in the other patients there were no such changes. Mental disturbances, which were a main cause of preoperative disability, disappeared in most cases. Two patients, however, continue to be invalidized from mental disease, which developed during the course of the hypercorticism.
One patient presented with a grossly evident pituitary tumour and in four other subjects a large pituitary tumour developed after adrenalectomy together with hyperpigmentation. Pituitary apoplexy occurred in one of these patients and another was operated upon because of visual field losses.
It is concluded that the remission obtained after adrenalectomy for Cushing's disease increases the survival rate and makes a normal life possible in most patients. However, persistent hypertension and cardiovascular disease as well as the possibility of the development of a pituitary tumour make the late prognosis somewhat uncertain.
MATHEMATICAL ANALYSIS FOR THE INTERPRETATION OF IN VIVO TRACER INFUSION EXPERIMENTS
Authors: Gurpide Erlio 
Published: October 2009

ABSTRACT
In vivo tracer experiments involving intravenous infusion of 1, 2 or 3 labelled hormones are described in schematic form. Formulae are provided to calculate from steady state isotopic data, rates of production and interconversion of circulating compounds, foeto-maternal production and transfer of hormones and rates of metabolic reactions occurring in an organ. Formal procedures to convert these formulae to expressions applicable to single injection experiments are outlined. The simplicity of the mathematical basis for the interpretation of most current experiments in hormone research is emphasized.
EVALUATION OF MECHANICAL SYSTEMS USED IN PERFUSION
Authors: Bernstein Eugene F. 
Published: October 2009

ABSTRACT
Among the critical factors in organ perfusion are (1) the mechanical components of the system, (2) the composition of the perfusate, and (3) the perfusing conditions. In this review, particular consideration is given to the pump, the oxygenator, and cannulas in such systems. Emphasis is placed upon the selection of pertinent equipment for the goals of a particular perfusion experiment, based upon the criteria of adequacy of the perfusion. Common problems in organ perfusion are summarized, and potential solutions to the perfusion problem, involving either biologic or mechanical extracorporeal systems, are suggested.
FUNCTIONAL ASSESSMENT OF AUTOTRANSPLANTED ENDOCRINE ORGANS
Authors: Goding J. R. , Baird D. T. , Cumming I. A. , McCracken J. A. 
Published: October 2009

ABSTRACT
Autotransplants of the adrenal gland and of the ovary have been extensively used to study basal secretion and mechanisms of control of steroid secretions by these organs. The validity of the use of such preparations for this purpose is critically examined in this paper.
Autotransplantation did not materially affect the normal histological architecture of the glands. The adrenal became re-innervated and re-connected to the lymphatic system. Sheep with their remaining adrenal gland transplanted to the neck not only survived for many years but also could support normal pregnancy. The blood flow through the transplants was somewhat greater than that from the organs in situ. This was shown to be due to (a) absence of acute vasoconstriction due to recent surgery, (b) some degree of admixture with peripheral blood, (c) compensatory hypertrophy. Steroid secretion from the autotransplants was similar to that from in situ glands and could be increased by specific stimuli. Biosynthetic transformations, with simultaneous measurements of hormone secretion rates, can be studied under controlled conditions. Cyclic behaviour was disturbed when the ovary alone was transplanted to the neck, but this was restored when the ovary and the uterus were transplanted together to a cervical site.
Impairment of cyclicity was shown to result from the separation of the ovary from the uterus. The uterus was shown to affect luteal function by secreting the prostaglandin (PG) F2α. PGF2α gained access to the ovarian circulation by a countercurrent mechanism which was demonstrated to be quantitatively competent to cause luteolysis in the normal animal. The minimum infusion rate of PGF2α into the uterine vein of sheep on day 7 of the cycle which would cause luteolysis was about 20 μg/h. This is similar to the observed rate of PGF2α secretion in the uterine vein of ewes at the time of luteolysis. Hence PGF2α can be regarded as »the« luteolytic hormone in the sheep, and the ovine uterus as an endocrine organ.
PREPARATION AND MECHANICAL PERFUSION OF THE ISOLATED MONKEY BRAIN
Authors: White Robert J. 
Published: October 2009

ABSTRACT
An isolated monkey brain model viably sustained by a mechanical extracorporeal perfusion system employing Dextran diluted subhuman primate blood has been developed. Each isolated brain is instrumented for continuously monitoring electrical activity (depth and cortical), ventricular pressure as well as intracerebral temperature and arterial (Circle of Willis) pressure. Employing EEG criteria the isolated brain approaches during the initial 60 to 90 minutes of perfusion the neurophysiological and metabolic performance of the intact brain. After the second hour of perfusion these preparations demonstrate accelerating electrical failure with an associated rise in excess lactate and a topographical cortical appearance consistent with developing cerebral oedema.
The solutions to problems of surgical isolation of the brain and design of extracorporeal perfusion support systems for this delicate organ as well as the performance of the isolated monkey brain are reviewed.
THE INFUSED TESTIS
Authors: Eik-Nes Kristen B. 
Published: October 2009

ABSTRACT
The infused testis has been discussed as a model system for studies of processes leading to formation and secretion of testosterone. While this model possesses certain advantages over other systems used in such studies, it is far from perfect and a rather large battery of techniques in vivo and in vitro are required in order to obtain adequate information on steroidogenesis in the male gonad.
THE STRUCTURE OF EUKARYOTE CHROMATIN
Authors: Dounce A. L. , Chanda S. K. , Ickowicz R. , Volkman D. , Palermiti M. , Turk R. 
Published: October 2009

ABSTRACT
In this paper certain aspects of the structure of chromatin are considered, with emphasis on the relationships of histone and residual protein to DNA. Recent findings relative to the complexing of histone with DNA are reviewed and material from this laboratory concerning the ratio of total histone to DNA and related topics are discussed. The questions of DNA strandedness and DNA repeating sequences are considered briefly. The relationship of residual protein of the cell nucleus to the structure of the chromosome is taken up and the bearing of the results of studies of nuclear gels on this problem are discussed. Recent results from this laboratory on the use of shear and a new autolytic procedure for detaching DNA from residual protein are outlined. The failure of residual protein to cause a marked elevation in the tm of nuclear DNA is discussed and material on the density gradient centrifugation of the DNA-residual protein complex is presented. Recent work on the fractionation of residual protein obtained from chromatin and isolated nuclei is critically reviewed. Finally a new hypothesis concerning a protein core structure in eukaryote chromosomes is presented briefly in the form of a model which may help to rationalize previously unexplained observations.
FUNCTIONAL STUDIES ON CHROMATIN
Authors: Paul J. , Carroll D. , Gilmour R. S. , More J. A. R. , Threlfall G. , Wilkie M. , Wilson S. 
Published: October 2009

ABSTRACT
Functional studies on chromatin include assays of template activity and template capacity. Template activity is the measure of the rate of polynucleotide synthesis supported by a chromatin template in an incubation mixture including exogenous DNA-dependent RNA polymerase. It can be a highly misleading criterion unless great care is taken to standardise conditions. Template capacity is the measure of the DNA in a preparation of chromatin as compared with purified DNA, which is accessible to transcription by exogenous DNA-dependent RNA polymerase. It is determined by studying the complexity of the RNA made in the reaction, usually by RNA-DNA hybridization. The effects of different methods of preparation of chromatin, different RNA polymerases, conditions of incubation and purification of RNA are discussed.
The application of these and other methods to the study of reconstituted chromatin is described.
ON THE ROLE OF RNA IN GENE AMPLIFICATION
Authors: Brown Ronald D. , Mattoccia Emilio , Tocchini-Valentini Glauco P. 
Published: October 2009

ABSTRACT
A complex of ribosomal DNA with RNA has been isolated from ovaries of metamorphosing tadpoles of Xenopus laevis. The complex is disrupted by treatments which destroy hydrogen bonds and the sedimentation of the DNA within the complex is sensitive to RNase. We suggest that the RNA: rDNA complex is an intermediate in the synthesis of amplified rDNA and that the role of the RNA in the process is that of a template. In addition, in a preliminary attempt to mimic the amplification process in vitro, we have demonstrated the use of this RNA from the complex as a template for DNA synthesis by a DNA polymerase isolated from ovaries of Xenopus.
RIBOSOME-MEMBRANE INTERACTION AND PROTEIN SYNTHESIS
Authors: Tata J. R. 
Published: October 2009

ABSTRACT
The role of secretion of proteins for the attachment of ribosomes to membranes has been well established. That another function must exist for membrane-ribosome interaction is suggested by observations on: (a) the active synthesis of proteins on membrane-bound ribosomes of predominantly non-protein secreting cells, and b) the massive proliferation of membrane-bound ribosomes during active growth and development of both secretory and non-secretory tissues.
Literature on functional and compositional differences between membrane-bound and free ribosomes is reviewed and it is proposed that a major function of ribosome-membrane interaction is to effect a topological segregation of different populations of ribosomes synthesizing different classes of proteins.
OVALBUMIN mRNA, COMPLEMENTARY DNA AND HORMONE REGULATION IN CHICK OVIDUCT
Authors: Schimke Robert T. , Rhoads Robert E. , Palacios Raphael , Sullivan Drew 
Published: October 2009

ABSTRACT
Chick oviduct differentiation is controlled by various steroid hormones, including both oestrogen and progesterone. Administration of oestrogen to chicks results in differentiation of tubular gland cells, which synthesize differentiated cell products, including ovalbumin and conalbumin. Ovalbumin can constitute as much as 60% of the protein synthesized by oviduct in the fully stimulated chick. Methods have been developed that allow for the quantitative assay of ovalbumin mRNA, the specific isolation of ovalbumin synthesizing polysomes by use of immunologic techniques, as well as the synthesis of a DNA probe complementary to the ovalbumin mRNA. With these techniques we have found that the rate of ovalbumin synthesis is proportional to the content of ovalbumin mRNA. Hybridization studies using the DNA probe indicate that there are only two copies of the ovalbumin gene per genome, and that there is no amplification of the ovalbumin genes to account for the large amount of ovalbumin synthesized.
TERATOGENIC SCREENING METHODS AND THEIR APPLICATION TO CONTRACEPTIVE PRODUCTS
Authors: Tuchmann-Duplessis H. 
Published: October 2009

ABSTRACT
After an analysis of the basic principles of teratogenic drug testing and the complexity of factors involved in the production of congenital malformations, the following topics are considered:
the mechanisms of the teratogenic action the role of the placenta in drug transfer the choice of an animal model for teratogenic testing of hormonal sex steroids the influence of oral contraceptives upon various phases of reproduction.
To compete with the various mechanisms which control the normal intrauterine development, multiple conditions have to be fulfilled. Such a situation occurs only occasionally in humans.
Much data are available but little knowledge exists regarding the teratogenic mechanisms and the precise role of the placenta in drug teratogenicity.
Great differences of reactions to drugs exist among various species. They can be related to differences in the enzymatic systems involved in the metabolic turnover of a drug, but in many cases no explanation is yet available.
It seems that preliminary screening of sex steroids could be done in rodents. This can contribute to the selection of interesting therapeutical agents and may aid in discovering potential side effects. Since the maintenance of pregnancy in rodents requires functioning ovaries, while in women and in primates the placenta takes over very early the hormonal control of pregnancy, it is suggested to use primates for the safety evaluation of contraceptive drugs. The results obtained in these species are likely to have good predictive value.
Oral contraceptives have no mutagenic effects, they do not produce chromosomal aberrations and seem to be devoid of teratogenic action.
Experimental and clinical data suggest that oral contraceptives have no adverse effects on the perinatal and postnatal development.
SPECIAL REQUIREMENTS FOR PLASTIC DEVICES
Authors: Bischoff Fritz , Bryson George 
Published: October 2009

ABSTRACT
The safety testing for polymers in contraceptive devices already in use, at the human pilot test stage, or proposed is appraised. At the subcutaneous and intraperitoneal sites in the rat, polyethylene did not demonstrate chemical carcinogenicity; in the uterine horn endometritis was a prelude to epidermoid carcinoma development. In rodents, polyvinyl chloride copolymer, vinyl chloride, liquid silicone, and other polymers may respond as chemical carcinogens. A polyvinyl chloride resin produced local uterine squamous cell carcinomas in rats and leiomyosarcomas in mice. Intrauterine implants produce a characteristic foreign-body reaction in all species studied, including man, and secondary infection in rats and mice. Solid-state carcinogenesis can no longer be regarded as a phenomenon exclusive for rodents. Because it depends upon a minimum implant period in situ and a long latent period, its appearance in humans should occur only after many years and only if the implant has resided more than temporarily.
When safety testing fails because of differences in response between species and/or anatomical test sites, evaluation of the effects of polymers already used for other purposes in humans and over long periods of time may be a necessary recourse. The tendency of the silicone prosthesis to mechanically erode its way through body tissues and to absorb lipids suggest general lack of biological inertness.
The development of a fibrous capsule around parenteral implants may decrease metabolic exchange and limit the use of polymer-hormone depots.