bluuebunny/crossref_metadata_2025 huggingface dataset:
RELATIONSHIP BETWEEN THE EFFECTS OF CONTRACTION AND INSULIN ON THE METABOLISM OF THE ISOLATED LEVATOR ANI MUSCLE OF THE RAT
Authors: Arvill A.
Published: October 2009

The effects of repetitive contractions of the isolated levator ani muscle of the immature male rat were investigated on glucose uptake, the accumulation of D-xylose-14C, and α-aminoisobutyric acid-14C (AIB-14C) as well as on the incorporation of leucine-3H, proline-3H and valine-14C into protein and adenine-14C into RNA. These effects were compared with the effects of insulin.

Glucose uptake and D-xylose-14C accumulation were increased during the period of contractions and after this period for at least three hours. Insulin and contractions had additive effects on these uptakes.

AIB-14C accumulation was also stimulated by contraction. This effect increased with the incubation time and was maximal at a frequency of 60 imp/min. The effect lasted for at least three hours after the period of contractions. The stimulating effect of insulin on AIB-14C accumulation in the muscle was reduced by contractions. A reduction was also obtained on the incorporation of normal amino acids into protein as well as on the incorporation of adenine-14C into RNA. The stimulating effect of insulin on the rate of incorporation of amino acids into protein was reduced during the contraction period.

No insulin-like activity could be found in the media of contracting muscles, when these media were tested with fresh muscles for effects on the accumulation of AIB-14C or D-xylose-14C.
TEMPORAL RELATIONSHIP OF THE GROWTH HORMONE EFFECTS ON AMINO ACID TRANSPORT AND PROTEIN SYNTHESIS IN ISOLATED RAT DIAPHRAGM
Authors: Hjalmarson Å.
Published: October 2009

Experiments were performed to study whether the influence of bovine growth hormone (GH) on the mebrane transport of labelled leucine and glycine in the isolated rat diaphragm was similar to that previously found for α-aminoisobutyric acid (Hjalmarson & Abrén 1967a, b). The relationship between the effects of GH on amino acid transport and protein synthesis was also studied.

Addition of GH in vitro (25 μg/ml) to intact hemidiaphragms from hypophysectomized rats increased the accumulation of glycine in the intracellular water after 2 hours of incubation, while that of leucine was reduced. GH in vitro increased the incorporation rate into muscle protein of both glycine and leucine.

An Intravenous (i. v.) injection of GH (10 μg) to hypophysectomized rats 60 min. before incubation increased the distribution ratio of leucine, while no significant effect was found on the incorporation into protein of this amino acid. On the other hand, an injection of GH (10 μg) 180 min. before incubation increased the in vitro incorporation of both leucine and glycine. This injection did not change the distribution ratio of glycine and that of leucine was significantly decreased.

Repeated injections of GH (50 μg × 4 days) increased the incorporation of both glycine and leucine. This treatment also increased the accumulation of glycine after 2 hours of incubation, while no such effect was seen on the accumulation of leucine.

In vitro addition of GH (25 μg/ml) did not significantly change the distribution ratio of glycine and leucine in diaphragms from hypophysectomized rats previously treated with GH. However, addition of GH in vitro to the diaphragms from these rats further increased the incorporation of glycine into protein. In addition, GH in vitro increased the accumulation of glycine also when the incorporation of this amino acid into protein was completely blocked by puromycin (500 μg/ml).

The present results show that GH, at least in certain doses, may have a biphasic action on the membrane transport of normal amino acids. The results also indicate that GH may have separate effects on the membrane transport and the incorporation into protein of amino acids.
Enzymic Correlates of Development, Secretory Function and Regression of Follicles and Corpora Lutea in the Bovine Ovary. PART III: Follicular Atresia
Authors: Lobel B. L. , Levy E.
Published: October 2009

Cytochemical changes in activities of hydrolytic enzymes and of dehydrogenases were studied during follicular atresia. Different patterns of enzymic activities were encountered in the different types of atretic follicles. When large vesicular follicles became atretic at the end of the cycle, they underwent a transient luteinization. On the basis of their cytochemical properties, it is suggested that such follicles may be one source of steroidal hormones in the bovine ovary, especially towards the end of the cycle. The bovine ovary apparently does not contain "interstitial tissue" capable of steroidogenesis.
IMMUNOASSAY OF GONADOTROPHINS USING COMPLEMENT FIXATION
Authors: Brody Sam
Published: October 2009

This report is a summary of 10 years of experience with the complement fixation test as adopted for the immunoassay of HCG in serum. It is based on published as well as unpublished material. The discussion centers mainly around methodological problems, criteria of reliability, and clinical observations.

It is our impression that the complement fixation test is a reasonably rapid and simple technical procedure. It is standard practice in every bacteriological and virological laboratory. The precision of the HCG assay is high. Its accuracy is good. The complement fixation assay, as reported here, fulfils the criteria of specificity. It has been evaluated by means of serological techniques and through comparison between biopotency and immunopotency of HCG in serum with reference to a common standard. Its application for routine as well as research work is illustrated.
RADIOIMMUNOASSAYS EMPLOYING DOUBLE ANTIBODY TECHNIQUES
Authors: Midgley A. Rees , Rebar Robert W. , Niswender Gordon D.
Published: October 2009

Double antibody methods are applicable to all radioimmunoassay systems. At least three approaches exist. The first, in which immunoprecipitating serum is used to precipitate soluble antigen-antibody complexes, is the most commonly used. Since the effects of interfering factors, especially those present in serum, become minimal as equilibrium is approached, care must be taken to insure that the period of incubation is of sufficient length for the immunoprecipitation reaction to reach equilibrium. In general, all efforts should focus on achieving reaction conditions which maximize stability and optimize immunoprecipitation. A second approach involves use of the first antiserum in an insolubilized form after prior precipitation with the immunoprecipitating antiserum. This approach is attractive since most non specific factors cannot interfere with the immunoprecipitation step to a significant extent once the formation of antigen-antibody aggregates is well underway. The third approach, in which immunoprecipitating antiserum is conjugated to a solid matrix, in principle represents a more ideal method of separating bound hormone from free. If this approach is ever to be utilized, a method of conjugating antiserum to a suitable matrix such that the antibody retains most of its immunoreactivity must be devised.
DISCREPANCIES AND SIMILARITIES OF URINARY FSH AND LH PATTERNS AS EVALUATED BY DIFFERENT ASSAY METHODS
Authors: Stevens Vernon C.
Published: October 2009

Patterns of urinary FSH and LH excretion during the normal human menstrual cycle have been extensively studied. A variety of urine extraction procedures and a variety of assay techniques have been used to define these patterns. LH excretion patterns have been relatively consistent among the numerous studies and a typical pattern consists of a single peak at midcycle. Variations in baseline LH patterns were observed. FSH excretion patterns have varied widely in the studies reported. Most investigators found FSH levels highest in the early follicular phase and at or near the middle of the cycle. Few studies have been reported in which sufficient points of reference to physiological measurements were made. Factors to be considered in the interpretation of assay data are discussed.
ZUR REGULATION DER PROTEINBIOSYNTHESE DURCH SEXUALHORMONE: DIE WIRKUNGEN VON OESTRADIOLBENZOAT UND VON TESTOSTERONPROPIONAT AUF DIE KONZENTRATION VON SERUMPROTEINEN
Authors: Oberdorfer Alfred
Published: October 2009

Following intramuscular injections of oestradiol-17 β 3-monobenzoate and testosterone propionate in domestic fowl, typical alterations in the immunoelectrophoretic, starchgelelectrophoretic and ultracentrifugal patterns of serum proteins were observed. These effects are due to alterations in the concentrations of specific serum proteins. Both sex hormones alter the concentrations of the same proteins. The concentrations of various proteins are increased by one of the two hormones and decreased by the other. The administration of oestradiol-17β 3-monobenzoate alters the serum-protein patterns of pullets and immature cocks, nonlaying mature hens and mature cocks towards the pattern characteristic for laying hens. Testosterone propionate alters the pattern of serum proteins for laying hens towards the pattern that is characteristic for pullets and immature cocks, nonlaying mature hens and mature cocks. These alterations are reversible. Both the extent and the duration of the alterations are dependent upon the amounts of the hormones given.

The results are discussed as being phenomena of hormonal effects on the biosynthesis of proteins. A comparison of the effects of the two sex hormones on the concentrations of total serum protein shows that in the case of oestradiol-17 β 3-monobenzoate the activating effects dominate. Testosterone propionate, however, seems to have more inhibitory effects than activating ones on the biosynthesis of proteins.

On the basis of the theory advanced by Jacob & Monod, concerning the regulation of protein biosynthesis, and related to Karlson's hypothesis of gene activation, a model is proposed for a theoretical explanation of the results obtained here. It is assumed that both sex hormones, acting as effectors, influence the function of repressors with complementary structures and in this way activate or inactivate specific gene loci that are responsible for the biosynthesis of proteins.
THEORETICAL ASPECTS OF SATURATION ANALYSIS
Authors: Ekins Roger , Newman Brian
Published: October 2009

'Saturation analysis' is the term originally proposed by one of us (Barakat & Ekins 1961) to describe the general analytical method relying on progressive saturation by the test compound of a specific reagent. It has, in the last ten years, been applied to widely differing groups of physiologically important compounds using a variety of classes of reactive material.

This review is intended to summarise the fundamental requirements of the method, with particular reference to the aim of achieving an 'accurate' result. Some of the mathematical principles underlying optimal assay design are discussed.
METHODOLOGICAL PROBLEMS IN COMPETITIVE PROTEIN-BINDING TECHNIQUES; THE USE OF SEPHADEX COLUMN CHROMATOGRAPHY TO SEPARATE STEROIDS
Authors: Pearson Murphy Beverley E.
Published: October 2009

The problems to be investigated in setting up a competitive protein-binding (CPB) assay have been considered: the choice of plasma protein, tissue protein or antibody as the assay protein; the separation of bound and unbound fractions; sample preparation with respect to the removal or destruction of interfering binding-proteins and the separation of competing analogues. Factors giving rise to blank values have been discussed as well as problems encountered in running CPB assays routinely.
MEASUREMENT OF STEROID BINDING PROTEINS
Authors: Baulieu E. E. , Raynaud J. P. , Milgrom E.
Published: October 2009

A brief review of the characteristics of steroid binding proteins found in the plasma and in some target organs is presented, followed by some general remarks on binding »specificity« and binding parameters. Useful techniques for measuring binding parameters at equilibrium are reported, both those which keep the equilibrium intact and those which implicate its disruption. A concept is developed according to which the determination of a specific steroid binding protein is based on the »differential dissociation« of the several steroid binding complexes present in most biological mixtures.

Methods which allow determination of the kinetic parameters of the binding systems are also presented.

Various representations of the binding and therefore different modes of graphic representation and calculation are discussed, including the recent »proportion graph« method.
ANALYSIS OF CORTICOSTEROIDS
Authors: Slaunwhite W. Roy , Sandberg Avery A.
Published: October 2009

Human transcortin or a high affinity, low capacity corticosteroid-binding protein from the plasma of various species has been used for corticosteroid analysis. The relative specificity varies with the species so that selection of the appropriate plasma source is advantageous. Endogenous steroids which interfere in the assay may be limited by administration of a synthetic glucocorticoid prior to collection of the binding plasma or they may be removed by charcoal adsorption. Interference from albumin (and other non-specific binding proteins) may be minimized by dilution of the plasma. Further dilution may be attained if the transcortin concentration is raised by estrogen stimulation.

Association of cortisol to human transcortin is virtually instantaneous and is limited in practice only by the rates of solution and diffusion. At 37° the rate of dissociation is also rapid (half-time ca. 10 sec.) so that only a short incubation time (5–15 min) is needed. With the almost universally accepted usage of non-equilibrium methods of separating bound from unbound steroid, it is imperative that separation be performed at low temperatures where the rate of dissociation is much less (half-time 25 min). There is insufficient information to decide which of the many variants of the technique is best for one particular corticosteroid. They all assume competing steroids to be negligible and, therefore, none (but one) of the variants incorporate a purification step (solvent partition or chromatography). In certain instances (late pregnancy, adrenogenital syndrome, metapyrone test) this can lead to varying degrees of error.
SEX STEROID BINDING PLASMA PROTEIN (SBP)
Authors: Mercier-Bodard C. , Alfsen A. , Baulieu E. E.
Published: October 2009

The detection, preparation from plasma Cohn fraction IV and purification of SBP are reported. The association constant has the value of K = 1.2 and 0.5 109 M−1 at 4°C for testosterone and oestradiol, respectively. A preparation homogeneous by the criteria of polyacrylamide gel electrophoresis, binding studies and ultracentrifugation is obtained; sedimentation equilibrium experiments give a molecular weight of approx. 52 000, confirming the approximative value obtained from Sephadex filtration.
CATECHOLAMINE ANTAGONISM TO OXYTOCIN-INDUCED MILK-EJECTION
Authors: Vorherr Helmuth
Published: October 2009

In lactating rats and rabbits the mode of antagonism of sympathomimetics, angiotensin or pain toward oxytocin-induced milk-ejection was investigated. In rats intra-arterial (intrafemoral) doses of 0.01–0.02 μg or intravenous (iv) doses of 0.1–0.5 μg of either epinephrine, isoproterenol, norepinephrine, angiotensin or 10 μg of phenylephrine injected simultaneously with, or 30 seconds before an oxytocin dose (10 μU intrafemoral, 300 μU iv) greatly inhibited or suppressed the oxytocin response. A 15 second pain stimulus caused moderate inhibition. With alpha-receptor blockade pain, epinephrine, isoproterenol, norepinephrine, phenylephrine and angiotensin inhibition were, respectively, 70%, 75%, 100%, 40%, 0% and 100%. Under beta-receptor blockade the corresponding values were 14%, 40%, 0%, 70%, 100% and 100%; with simultaneous intrafemoral injections neither catecholamine was inhibitory toward oxytocin. In corresponding rabbit experiments approximately 10-fold higher iv drug dosages were applied and similar results were observed. In both species, combined alpha and beta-receptor blockade nearly eliminated the antagonistic actions of sympathomimetics toward oxytocin, whereas angiotensin inhibition persisted unchanged.

The results indicate: 1) Mammary myoepithelial cells contain beta-adrenergic receptors but no alpha-receptors; 2) Inhibition of oxytocin-induced milk-ejection by isoproterenol and phenylephrine is meditated through stimulation of myoepithelial beta-receptors (myoepithelial relaxation) and vascular alpha-receptors (vasoconstriction), respectively; 3) Epinephrine and norepinephrine inhibition of milk-ejection is due to stimulation of vascular alpha-receptors and myoepithelial beta-receptors; 4) Angiotensin effects are unrelated to adrenergic receptor mechanisms; 5) Administration of both alpha and beta-adrenergic blockers is desirable for stabilizing the sensitivity of the oxytocin milk-ejection assay preparation against interference from endogenous or exogenous catecholamines; 6) Other than using adrenergic blockers, pharmacologic doses of oxytocin can correct nursing difficulties in animals and man with hyperfunction of the adrenal-sympathetic system.
METHODS FOR METABOLIC STUDIES ON ISOLATED GRANULOSA AND THECA CELLS
Authors: Hamberger L. , Hamberger A. , Herlitz H.
Published: October 2009

A review is given of methods for biochemical studies on isolated ovarian cells of various origin. Special attention has been paid to the methodological problems involved in the micro-dissection of homogeneous cell samples. The main results on the capacity of granulosa and theca cells to synthetize various steroids are summarized and discussed.

Methods to study respiration, on a micro-scale, of isolated ovarian cells from the rat are described. The techniques which require minute amounts of cells for each determination allow multiple analyses on cells isolated from the same follicle. The application of the techniques for studies on gonadotrophic influence upon ovarian cells from the prepubertal rat is illustrated. The effects of various gonadotrophins on succinate and glucose oxidation demonstrate that LH and FSH selectively stimulate oxidative processes in various types of ovarian cells.

Other techniques which are applicable for studies of proteins, enzymatic activities, RNA and electrolyte content in isolated ovarian cells are briefly discussed.
ISOLATION AND CYTOCHEMICAL PROPERTIES OF HUMAN ENDOMETRIAL CELLS
Authors: Johannisson Elisabeth , Hagenfeldt Kerstin
Published: October 2009

Quantitative cytochemical methods were employed for the determination of some cellular properties of isolated endometrial cells. Two different methods have been used: an absorption microspectrophotometric method for the estimation of Feulgen-DNA and a microfluorometric technique for the assessment of glycogen. The two methods have been evaluated with respect to their specificity when applied to isolated human endometrial cells.

The variation in endometrial DNA and glycogen during the menstrual cycle was studied in isolated cells taken from normally menstruating women. During the first part of the proliferative phase from cycle day (c. d.) 1 to c. d. 10–11 the Feulgen-DNA values in the endometrial cells remained at a constant level, corresponding to the pre-synthesizing phase (G1). However, in the samples obtained from cycle days 14, 16–18, and 19–23 the cells were mainly in the DNA-synthesizing phase (S), revealing a higher amount of Feulgen-DNA per nucleus than in the early proliferative phase. By c. d. 27 a statistically significant drop in Feulgen-DNA per cell nucleus was found and the endometrial cells were again in G1-phase.

The deposit of glycogen showed a gradual increase from c. d. 1 to c. d. 16–18, with a slope of 0.0079 ± 0.0022. This was followed by a significant decrease between c. d. 16–18 and c. d. 27 with a slope of −0.0139 ± 0.0042.

Stromal glycogen remained low and constant throughout the entire menstrual cycle.
ENRICHMENT CULTURE TECHNIQUES FOR SELECTION OF CELL CULTURE STRAINS WITH DESIRABLE PHYSIOLOGICAL AND GENETIC PROPERTIES
Authors: Sato Gordon , Clark Jeffrey , Posner Martin , Leffert Hyam , Paul Dieter , Morgan Michael , Colby Clarence
Published: October 2009

Experimental approaches for selecting hormone-dependent cells, hybrid cells, and haploid cells are discussed. Experiments are described for isolating mammary tumour cells which are dependent on the presence of prolactin and insulin for growth.
APPLICATION OF PEROXIDASE-LABELLED ANTIBODIES TO THE INTRACELLULAR LOCALIZATION OF HORMONES
Authors: Nakane Paul K.
Published: October 2009

Hormones were localized immunoenzymocytochemically at the ultrastructural level directly on ultrathin sections of anterior pituitary glands of rats which had been fixed and embedded in either methacrylate or Epon. GH, LTH, ACTH and LH are best localized on methacrylate embedded glands and GH and LTH on Epon embedded glands. GH and LTH were found in secretion granules, and depending on the activity of the cells, the hormones could be found in the Golgi apparatus and in the cisternae of endoplasmic reticulum. The grids on which hormones have been localized may also be processed for electron radioautography, an approach particularly useful to study simultaneously substrate uptake as well as product synthesis.
STEROID HORMONE METABOLISM IN RESPONSIVE TISSUES IN VITRO
Authors: Robel Paul
Published: October 2009

Of the information available on steroid hormone metabolism in responsive tissues, only that relating hormone metabolism to physiological activity is reviewed, i. e. metabolite activity in isolated in vitro systems, binding of metabolites to target tissue receptors, specific steroid hormone metabolizing enzymes and relationship of hormone metabolism to target organ physiological state.

Further, evidence is presented in the androgen field, demonstrating 5α-reduced metabolites, formed inside the target cells, as active compounds. This has led to a consideration of testosterone as a »prehormone«. The possibility that similar events take place in tissues responding to progesterone is discussed.

Finally, the role of hormone metabolism in the regulation of hormone availability and/or renewal in target cells is discussed. In this context, reference is made to the potential role of plasma binding proteins and cytosol receptors.
SURVIVAL AND GONADOTROPHIN RESPONSIVENESS OF LUTEAL CELLS IN VITRO
Authors: Hansel William
Published: October 2009

Simplified methods for incubating luteal tissues have been developed. Progesterone biosynthesis in washed, minced bovine luteal tissue is stimulated by added bovine LH. The response is linear in the range 2–200 ng added LH per ml of medium. The use of covariance analysis to correct for differences in time elapsing between mincing the tissue and the beginning of incubation reduces the standard error of the mean and results in marked improvement in the indices of precision. Progesterone biosynthesis in washed, minced bovine luteal tissues appears specific for LH; no other pituitary hormones give a response, and the response is completely negated by adding anti-bovine LH serum to the incubation medium. Prior treatment of cattle from which the incubated corpora lutea are obtained with various levels of human chorionic gonadotrophin, results in greatly increased luteal tissue weights. However, this tissue has a markedly reduced sensitivity to LH added in vitro. No conclusive evidence was found for a feedback inhibition of progesterone on its own synthesis in this system. The incubation system developed is sensitive enough to serve as a bioassay for LH in biological tissues and fluids. Preliminary data suggest that a simplified protein binding assay can be successfully used to measure the progestins synthesized by minced, washed bovine luteal tissue in response to added bovine LH.
MORPHOLOGICAL EVALUATION OF PERFUSED TISSUES
Authors: Panigel Maurice
Published: October 2009

Morphological evaluation of perfused or preserved tissues can establish the extent of damage to the cellular architecture (vasculature, connective tissue, parenchymal cells) as a result of organ distress during the experimental procedure. Distress in perfused organs becomes evident by a rise of the vascular resistance to the perfusion flow and by an increase in the interstitial oedema which is easily detected and measured but is difficult to prevent in long term experiments.

There exists a hierarchy of preservability for the different tissues but the haemochorial human (or monkey) placental membrane is a unique structure for assessing morphological and functional integrity of the layers (trophoblast, villous stroma, endothelium) which separate the two different perfusion streams in the maternal and foetal blood channels.

In this review, emphasis has ben placed on two essential criteria to evaluate placental viability and functional capacity:

– the control of the efficiency of perfusion by radio-angiographic visualization of the diffusion of the perfusate in the isolated placental lobule.

– the histological and electron microscopical study of placental biopsies and post perfusion controls.

Similarly to the case in other tissues, light microscopy of the placenta only shows the gross alterations due to prolonged unsatisfactory survival conditions in vitro. Electron microscopy, however, provides a sensitive morphological test to detect early changes in the metabolic activity of the trophoblast and to control the integrity of the foetal capillary wall. Ultrastructural alterations, when they appear, are first seen at the cell borders and in the organelles (endoplasmic reticulum, mitochondria, lysosomes) of the syncytiotrophoblast layer. The endothelial cell lining of foetal capillaries usuallly remains intact during the first hours of a satisfactory perfusion with dilute blood but a swelling of the endothelium and abnormal endothelial cytoplasm projections in the capillary lumen may be observed when other perfusion fluids are used.

The physiological importance of the lysosome-like bodies found in the apical cytoplasm of the syncytiotrophoblast and the in vitro stability of the lysosomal membrane necessitate further investigations.
TECHNIQUES FOR THE COLLECTION OF LYMPH WITH SPECIAL REFERENCE TO THE TESTIS AND OVARY
Authors: Morris Bede , McIntosh G. H.
Published: October 2009

This paper describes the general surgical procedures used for cannulating lymphatics and for collecting lymph from various tissues of the body. Special reference is made to the lymphatic drainage of the testis and ovary of the sheep and to the relationships of the lymphatics and blood capillaries in these organs to the hormone secreting cells. The formation of lymph in these organs is related to some of their physiological activities, and details of the biochemical composition of testicular and ovarian lymph are given. The role of the lymphatic system in hormone transport and the possible significance of the composition of the interstitial fluid in regulating the synthesis and secretion of hormones is discussed.
LIVER PERFUSION IN THE STUDY OF HORMONE EFFECTS ON THE IONIC CONTENT AND MEMBRANE POTENTIAL OF LIVER CELLS
Authors: Lambotte L. , Kestens P. J.
Published: October 2009

Factors responsible for the success of canine liver perfusion are reviewed along with the description of the method used by the authors; emphasis is placed on the avoidance of anoxia, perfusion with blood by the hepatic artery and the portal vein, use of optimal values for haematocrit, pCO2 and temperature. The validity of this method of perfusion is established by biochemical tests but also by its ability to support the viability of livers before transplantation.

The monitoring of the perfusion is obtained with an on line digital computer gathering data from autoanalyzers, transducers (temperature, pressure) and from intracellular microelectrodes for the measurement of the membrane potential of the liver cell.

Various applications of this system to the study of ionic movements are described. Non-hormonal factors, such as temperature or pH changes modify the ion concentration and the membrane potential; some of the mechanisms involved are briefly discussed. Epinephrine injection produces by stimulation of the α receptor an hepatic potassium loss coupled with an equivalent sodium gain which are concomitant to a marked depolarization. These phenomena can be related to an increase in membrane permeability to the sodium ion. Comparisons are made between the stimulation of a and β adrenergic receptors. The effect of insulin on potassium uptake is studied during liver perfusion and in vivo in order to demonstrate antagonism between insulin on one hand and glucagon and cyclic AMP on the other hand.

In conclusion, liver perfusion offers some advantage over in vivo or other in vitro techniques but the method employed must maintain the liver in perfect functional condition. The measurement of membrane potential could be used to evaluate the viability of the perfused liver.
PERFUSION OF THE THYROID
Authors: Folkman Judah , Gimbrone Michael A.
Published: October 2009

Thyroid glands maintained by isolated perfusion have been used for studies in metabolism, micro-circulation and tumour angiogenesis. Recent work is described.

Thyroid metabolism can be studied for brief periods of 4–5 hours, after which there is progressive parenchymal damage. Pulsatile flow, and anti-coagulated whole blood or platelet-rich plasma provide for optimum perfusion conditions at normothermic temperatures.

There is gradual degeneration of capillary endothelium in every isolated thyroid perfusion. For this reason, tumours implanted into these organs, fail to become vascularized. This failure of angiogenesis in the isolated perfused organ, has been demonstrated to stop tumour growth at 1 to 2 mm in diameter.

The isolated perfused thyroid gland has also been used to elucidate the role of platelets in nurturing capillary endothelium. Platelets appear to play an essential role in the prevention of endothelial degeneration and its sequelae under normothermic perfusion conditions.
PERFUSION OF OVARIES IN VITRO AND IN VIVO
Authors: Ahrén Kurt , Janson Per Olof , Selstam Gunnar
Published: October 2009

This paper discusses in vivo and in vitro ovarian perfusion systems described so far in the literature. The interest is not focussed primarily on the results of these studies but rather on the advantages and disadvantages of the techniques and methods used. Another part of the paper summarizes the points which are most important, in our opinion, to take into consideration when developing an in vitro perfusion technique of the ovary. The last part of the paper gives a description of and some preliminary results from an in vitro perfusion system of the rabbit ovary which is under development in this laboratory.
EXTRACORPOREAL PERFUSION OF THE HUMAN FOETUS, PLACENTA AND FOETO-PLACENTAL UNIT
Authors: Lerner U. , Saxena B. N. , Diczfalusy E.
Published: October 2009

A system is described for the extracorporeal perfusion of the human foeto-placental unit at midgestation. The same system is used for the perfusion of isolated midgestation foetuses and midgestation or term placentas.

Various gas mixtures were used for the oxygenation of the blood to be perfused, and the pH, pO2 and pCO2 values were monitored at frequent intervals in the perfused blood as well as in the various perfusates. Compared with the values reported for maternal arterial blood, oxygenation of the blood to be perfused with an air + CO2 mixture (23.1 % O2 + 3.5–3.7 % CO2) yielded a normal pH and almost normal pO2 and pCO2 values, whereas oxygenation with carbogen (93.7 % O2 + 6.3 % CO2) resulted in low pH, highly elevated pO2 and almost normal pCO2 values.

In all foetal, placental and foeto-placental perfusions conducted at 36°C, the use of blood oxygenated with the air + CO2 mixture resulted in significantly better pH, pO2 and pCO2 values of the perfusates than when blood oxygenated with carbogen was employed. However, the pH, pO2 and pCO2 values in the perfusates obtained in the former series of experiments were still outside the range of normal values reported in the literature.
HUMAN CHORIONIC SOMATOMAMMOTROPIN (HCS) PLASMA LEVELS IN NORMAL AND PATHOLOGICAL PREGNANCIES AND THEIR CORRELATION WITH THE PLACENTAL FUNCTION
Authors: Genazzani A. R. , Cocola F. , Neri P. , Fioretti P.
Published: October 2009

The results of a study of HCS plasma levels and behaviour in normal and pathological pregnancies may be summarized as follows: a) HCS plasma levels gradually increase during normal pregnancy, reaching the highest values at the 38–39th week after the last menstrual period; in the last few days of pregnancy and just before labour a slight decrease is observed; b) in threatened abortion the behaviour of HCS plasma levels in successive assays clearly divides the cases ending in spontaneous abortion (low or decreasing levels) from those favourably resolved; c) in molar pregnancies the very low HCS plasma levels support the diagnosis; d) in Rhesus-isoimmunization the HCS plasma levels are near normal in all the cases in which the foetus is only slightly affected. On the contrary, very high levels were found in cases of foeto-placental hydrops and the rapid increase in HCS plasma levels in these cases seems to correlate with the appearance of hydropic conditions; e) in diabetic pregnancies, the HCS plasma levels are normal or slightly below normal; decreasing HCS values in subsequent assays preceded the intra-uterine foetal death (IUFD) in one case; two cases of juvenile diabetes treated with less than the required doses of insulin showed very high HCS values; f) in preeclamptic pregnancies the HCS levels are lower than normal and show no further increase after the 32–33rd week; several cases followed up for some weeks support this observation, and cases ending in IUFD or premature labour showed very low HCS levels; g) similarly, low HCS levels which failed to increase in subsequent assays are found in all the cases of foeto-placental dystrophy and multiple placental infarct; h) the cases of IUFD in uncomplicated pregnancies examined during the first 24 hours after the IUFD demonstrate normal or raised HCS levels in three cases where IUFD occurred before the 27th week, and below normal values in 7 out of 9 cases where IUFD occurred afterwards; i) higher than normal levels are demonstrated in twin pregnancies and pregnancies with large babies; j) a significant correlation between the foetal weight and the HCS levels is demonstrated if the plasma samples are collected at least five days before delivery; k) in prolonged pregnancy the observation of low HCS levels clearly indicates the presence of foetal post-maturity or chronic foetal distress; in fact, in uncomplicated prolonged pregnancies the HCS plasma levels are similar to those found in normal pregnancy at term.

All these data indicate the value of plasma HCS radioimmunoassay in an evaluation of the placental function and sustain the importance of its application during the whole pregnancy, and in the presence of any pathological condition of gestation.
METHODS FOR STUDYING PROTEIN-NUCLEIC ACID INTERACTION
Authors: Bourgeois Suzanne
Published: October 2009

Attention is focused on the study of regulatory proteins, repressors or activators, which bind DNA to inhibit or stimulate transcription, respectively.

The best characterized examples of repressors and activators, isolated from bacteria or phages, are cited. Some general properties are pointed out, which appear to be common to all proteins binding DNA with great specificity and high affinity. The techniques available for their purification and fractionation are mentioned.

Sensitive methods for the study of protein-nucleic acid interaction involve the separation of the radioactively labelled nucleoprotein complex from the free labelled reactant. Different techniques that can be used are briefly outlined. The membrane filter technique, which is most sensitive, convenient and fast, is discussed in detail.

The membrane filter technique is illustrated by its use in the study of the E. coli lactose operon repressor-operator interaction. The binding constant for that interaction is Kd = 10−13m. The effects of a variety of parameters on the binding, as well as the mode of action of inducers and anti-inducers, are known. The rate constants for the repressor-operator association and dissociation have been measured. Repressors altered by mutations have been characterized. The membrane filter technique also provides an assay and a means to purify operator DNA.

The approach to similar studies in an animal cell system is briefly discussed.
MORPHOLOGICAL STUDIES OF TRANSCRIPTION
Authors: Miller O. L. , Bakken Aimée H.
Published: October 2009

Preparative techniques are detailed for isolating nuclear contents of amphibian oocytes and HeLa cells for electron microscopy, and the ultrastructure of presumptive ribosomal RNA (rRNA) genes and other active chromosomal loci is described. The rRNA genes from the two cell types present strikingly similar structural configurations, both being fully loaded with RNA polymerases and exhibiting gradients of short to long nascent ribonucleoprotein (RNP) fibrils. Other chromosomal loci in the two cell types are strikingly different; those on lampbrush chromosomes of amphibian oocytes show closely-spaced polymerases and extremely long RNP fibrils, whereas those on HeLa genomes have widely-spaced polymerases and relatively short attached RNP fibrils.
STRUCTURAL AND FUNCTIONAL PROPERTIES OF THREE MAMMALIAN NUCLEAR DNA-DEPENDENT RNA POLYMERASES
Authors: Chambon P. , Gissinger F. , Kedinger C. , Mandel J. L. , Meilhac M. , Nuret P.
Published: October 2009

Three DNA-dependent RNA polymerases AI, BI and BII were purified from calf thymus. These enzymes were characterized by their sensitivity to amanitin, their subunit pattern and their template specificities. Enzyme AI is resistant to amanitin, while B enzymes are inhibited by this poison. Each of these enzymes contains two subunits of high molecular weight: A1 (M.W. 197 000) and A2 (M.W. 126 000) for enzyme AI, Bl (M.W. 214 000) and B3 (M.W. 140 000) for enzyme BI, B2 (M.W. 180 000) and B3 for enzyme BII. In addition, each enzyme contains several subunits of lower molecular weight. Purification of B enzymes from rat liver showed the presence of two enzymes similar to calf thymus RNA polymerases BI and BII and suggested the existence of an additional B enzyme in rat liver. The number of RNA polymerase form B molecules was determined in a variety of animal tissues by binding of labelled amanitin. The values ranged from 1 × 104 to 6.5 × 104 molecules per haploid genome.

Studies with derivatives of rifamycin indicated that calf thymus B enzymes were able to recognize specific initiation sites on calf thymus DNA, which were different from those recognized by enzyme AI or E. coli RNA polymerase. These results favour the hypothesis that the multiplicity of animal RNA polymerases could play an active role in the control of transcription.
DNA-RNA HYBRIDIZATION
Authors: Bishop J. O.
Published: October 2009

The kinetics of ideal DNA-RNA hybridization reactions are described, and some deviations from ideal behaviour are noted. The characteristics of RNA excess and DNA excess reactions are described, and different approaches to experimental situations are discussed.
mRNA STABILITY AND CELLULAR DIFFERENTIATION
Authors: Kafatos Fotis C.
Published: October 2009

The diversity of mRNA half-lives was investigated in a differentiated insect tissue, the silkmoth galea, which is specialized for production of a characteristic protein, the zymogen of the proteolytic enzyme, cocoonase. It appears that the differentiation-specific cocoonase mRNA is uniquely stable (half-life ca. 100 h). In addition, the non-specific mRNAs (average half-life ca. 2.5 h) show considerable variability in terms of stability. General methods are described for evaluating half-lives of mRNAs coding for distinguishable semipurified proteins. Some of the limitations of these procedures are also discussed.

The observations that mRNA half-lives are variable, and that the differentiation-specific mRNA is unusually stable, have numerous developmental implications. A key role is attributed to differential mRNA stability in a quantitative model of developmental regulation.
PROTEIN-RNA INTERACTIONS IN BACTERIAL RIBOSOMES
Authors: Garrett R. A. , Wittmann H. G.
Published: October 2009

There are several ribosomal proteins which can bind specifically to the three ribosomal RNA's of E. coli. Some structural properties of these proteins and of the RNA are described together with the optimal conditions for binding. Evidence for conformational changes occurring in some proteins, and in the RNA's during binding, is also discussed.

The partial localisation of protein binding sites on the 16S and 5S RNA's, and for one protein on the 23S RNA has been attained recently. However, relatively little is known about the regions of the protein which interact with the RNA. Although the nature of the specificity of the protein-RNA interactions is not yet understood, some experimental approaches which are in progress to elucidate the basis of this specificity are mentioned together with a discussion of the structural factors which may be important.
THE TRANSLATION OF MESSENGER RNA INJECTED IN LIVING OOCYTES OF XENOPUS LAEVIS
Authors: Gurdon J. B.
Published: October 2009

Messenger RNA (mRNA) can be injected in known quantities into oocytes of the frog Xenopus laevis. Haemoglobin mRNA from rabbit, mouse, or duck blood cells is accurately translated, and oocytes can translate messages from different cell-types of all vertebrate groups. Oocytes and eggs have a spare capacity to translate injected messages, even when supplied in excess, and these do not compete with the cells' own messages already in use. The cell component which restricts the translation of injected mRNA above a saturating amount appears not to be KCl-released ribosome factors or transfer RNA. A message-specific component may be responsible for the lower efficiency of translation of α than of β globin mRNA in oocytes. Injected haemoglobin mRNA appears to be translated less frequently in oocytes than in reticulocytes at the same temperature, but continues to be translated in oocytes at nearly the same rate for a period of up to nearly 2 weeks. The injection of mRNA into oocytes is especially valuable for studying the control of protein synthesis in living cells.
NON-RIBOSOMAL POLYPEPTIDE SYNTHESIS
Authors: Lipmann Fritz
Published: October 2009

The biosynthesis of the cyclic decapeptide antibiotic, tyrocidine, was analyzed in particle-free supernatant fractions of RNase-treated homogenates of Bacillus brevis ATCC 8185. From the extracts, three complementary fractions with molecular weights of (1) 100 000, (2) 230 000, and (3) 440 000 were obtained. (1) activates and racemizes the initiating phenylalanine, (2) activates the three following amino acids, and (3) activates the last six amino acids by primary reaction with ATP to AMP-amino acid and secondary transfer to an enzyme-bound -SH. The enzymes alone fix amino acids but do not polymerize. The mixture, on sequential addition of amino acids + ATP, polymerizes first to enzyme-bound polypeptides, which after addition of all ten amino acids, cyclize. The enzymes (2) and (3) each contain one mole of 4'-phosphopantetheine which appears to act in transpeptidation. By mild autolysis and dodecyl sulphate gel electrophoresis, the polyenzymes may be split to subunits of 70 000 molecular weight, retaining only amino acid activation.

In recent attempts to analyze the biosynthesis of the thyrotropic release hormone, a tripeptide made in the hypothalamus, we have met with great difficulties due to the presence of potent peptidases in brain preparations.
PROTEIN SYNTHESIS IN MAMMARY GLAND
Authors: Gaye Pierre , Houdebine Louis , Pétrissant Guy , Denamur Robert
Published: October 2009

The induction of the synthesis of milk proteins is accompanied by a very large increase in the number of polyribosomes in the cells of the mammary gland. The two classes of polyribosomes (free and membrane-bound) possess very different degrees of aggregation. The ratio of bound to free polyribosomes is very high in the normally lactating gland, or after stimulation by prolactin. On the other hand, it is low after inhibition of milk secretion by progesterone. The synthesis of milk proteins is almost exclusively the consequence of activity of bound polyribosomes and the rate of turnover of the RNA content of mRNP is also more rapid for free than for bound polyribosomes. mRNAs were prepared from bound polyribosomes by sucrose-gradient ultracentrifugation and by chromatography on poly U Sepharose. The fractions thus isolated were capable of directing the synthesis of casein αs, β and K in heterologous cell-free systems. Some of the mRNAs for αs casein contained a significant poly A sequence. The control of the synthesis of mammary proteins by initiation factors and tRNAs is discussed. The purification of 2 isoacceptors of Met tRNA has enabled us to show that the mammary initiator tRNA does not possess the sequence GTψC which is present in all other tRNAs.
PRACTICAL SCREENING FOR DIABETES MELLITUS IN PREGNANT WOMEN
Authors: Guttorm Eigil
Published: October 2009

A prospective and consecutive investigation of 1697 pregnant women without earlier known diabetes and a retrospective investigation of 120 pregnant diabetics (White class A: 94, White class B: 26), has been performed. It was found that:

the most useful criteria of potential diabetics were: 1) the presence of diabetes in close relatives, diagnosed before the age of 40 years, 2) the presence of obesity in the patients, defined as 20 per cent overweight or more just before pregnancy, 3) previous delivery of a big baby, defined as a baby with birthweight ≦ 4500 g. Of the 1697 pregnant women 8 per cent were potential diabetics and in 8 per cent glucosuria was found.

pregnant women with glucosuria and potential diabetics defined as above had a higher risk of having a diabetic OGTT than other pregnant women.

A diabetic OGTT was found with falling incidence in the groups: potential diabetics with glucosuria: 10.5 per cent, non-potential diabetics with glucosuria: 3.7 per cent, potential diabetics without glucosuria: 3.4 per cent, and in the control group (non-potential diabetics without glucosuria): 0.3 per cent.

A positive correlation was found between the level of fasting plasma glucose (FPG) early in pregnancy, and the result of OGTT later in pregnancy. When FPG exceeded 89 mg/100 ml (75 mg/100 ml whole blood) the incidence of diabetic curves increased significantly.

By combining the following criteria: potential diabetics – glucosuria – fasting plasma glucose, FPG, it was found that the percentage of pregnant women, which ought to be investigated with an OGTT, could be reduced to 4 per cent, while the sensitivity and the specificity of the screening was 78 per cent and 89 per cent, respectively.

This approach also resulted in the detection of all the most treatmentrequiring cases of diabetes. The practical use of the screening method is described.