bluuebunny/crossref_metadata_2025 huggingface dataset:
Grafting Neural Precursor Cells Promotes Functional Recovery in an SCA1 Mouse Model
Authors: Chintawar Satyan , Hourez Raphael , Ravella Ajay , Gall David , Orduz David , Rai Myriam , Bishop Don Patrick , Geuna Stefano , Schiffmann Serge N. , Pandolfo Massimo
Published: October 2009

The B05 transgenic SCA1 mice, expressing human ataxin-1 with an expanded polyglutamine tract in cerebellar Purkinje cells (PCs), recapitulate many pathological and behavioral characteristics of the neurodegenerative disease spinocerebellar ataxia type 1 (SCA1), including progressive ataxia and PC loss. We transplanted neural precursor cells (NPCs) derived from the subventricular zone of GFP-expressing adult mice into the cerebellar white matter of SCA1 mice when they showed absent (5 weeks), initial (13 weeks), and significant (24 weeks) PC loss. Only in mice with significant cell loss, grafted NPCs migrated into the cerebellar cortex. These animals showed improved motor skills compared with sham-treated controls. No grafted cell adopted the morphological and immunohistochemical characteristics of PCs, but the cerebellar cortex in NPC-grafted SCA1 mice had a significantly thicker molecular layer and more surviving PCs. Perforated patch-clamp recordings revealed a normalization of the PC basal membrane potential, which was abnormally depolarized in sham-treated animals. No significant increase in levels of several neurotrophic factors was observed, suggesting, along with morphological observation, that the neuroprotective effect of grafted NPCs was mediated by direct contact with the host PCs. We postulate that a similar neuroprotective effect of NPCs may be applicable to other cerebellar degenerative diseases.
Endocannabinoid-Dependent Homeostatic Regulation of Inhibitory Synapses by Miniature Excitatory Synaptic Activities
Authors: Zhang Si-yu , Xu Min , Miao Qing-long , Poo Mu-ming , Zhang Xiao-hui
Published: October 2009

Homeostatic regulation of synaptic strength in response to persistent changes of neuronal activity plays an important role in maintaining the overall level of circuit activity within a normal range. Absence of miniature EPSCs (mEPSCs) for a few hours is known to cause upregulation of excitatory synaptic strength, suggesting that mEPSCs contribute to the maintenance of excitatory synaptic functions. In the present study, we found that the absence of mEPSCs for 1–3 h also resulted in homeostatic suppression of presynaptic functions of inhibitory synapses in acute cortical slices from juvenile rats, as suggested by the reduced frequency (but not amplitude) of miniature IPSCs (mIPSCs) as well as the reduced amplitude of IPSCs. This homeostatic regulation depended on endocannabinoid (eCB) signaling, because blockade of either the activation of cannabinoid type-1 receptors (CB1Rs) or the synthesis of its endogenous ligand 2-arachidonoylglycerol (2-AG) abolished the suppression of inhibitory synapses caused by the absence of mEPSCs. Blockade of group I metabotropic glutamate receptors (mGluR-I) also abolished the suppression of inhibitory synapses, consistent with the mGluR-I requirement for eCB synthesis and release in cortical synapses. Furthermore, this homeostatic regulation also required eukaryotic elongation factor-2 (eEF2)-dependent protein synthesis, but not gene transcription. Activation of eEF2 alone was sufficient to suppress the mIPSC frequency, an effect abolished by inhibiting CB1Rs. Thus, mEPSCs contribute to the maintenance of inhibitory synaptic function and the absence of mEPSCs results in presynaptic suppression of inhibitory synapses via protein synthesis-dependent elevation of eCB signaling.
Protein Kinase C Mediates the Synergistic Interaction Between Agonists Acting at α2-Adrenergic and Delta-Opioid Receptors in Spinal Cord
Authors: Overland Aaron C. , Kitto Kelley F. , Chabot-Doré Anne-Julie , Rothwell Patrick E. , Fairbanks Carolyn A. , Stone Laura S. , Wilcox George L.
Published: October 2009

Coactivation of spinal α2-adrenergic receptors (ARs) and opioid receptors produces antinociceptive synergy. Antinociceptive synergy between intrathecally administered α2AR and opioid agonists is well documented, but the mechanism underlying this synergy remains unclear. The delta-opioid receptor (DOP) and the α2AARs are coexpressed on the terminals of primary afferent fibers in the spinal cord where they may mediate this phenomenon. We evaluated the ability of the DOP-selective agonist deltorphin II (DELT), the α2AR agonist clonidine (CLON) or their combination to inhibit calcitonin gene-related peptide (CGRP) release from spinal cord slices. We then examined the possible underlying signaling mechanisms involved through coadministration of inhibitors of phospholipase C (PLC), protein kinase C (PKC) or protein kinase A (PKA). Potassium-evoked depolarization of spinal cord slices caused concentration-dependent release of CGRP. Coadministration of DELT and CLON inhibited the release of CGRP in a synergistic manner as confirmed statistically by isobolograpic analysis. Synergy was dependent on the activation of PLC and PKC, but not PKA, whereas the effect of agonist administration alone was only dependent on PLC. The importance of these findings was confirmedin vivo, using a thermal nociceptive test, demonstrating the PKC dependence of CLON-DELT antinociceptive synergy in mice. That inhibition of CGRP release by the combination was maintained in the presence of tetrodotoxin in spinal cord slices suggests that synergy does not rely on interneuronal signaling and may occur within single subcellular compartments. The present study reveals a novel signaling pathway underlying the synergistic analgesic interaction between DOP and α2AR agonists in the spinal cord.
Distributed and Antagonistic Contributions of Ongoing Activity Fluctuations to Auditory Stimulus Detection
Authors: Sadaghiani Sepideh , Hesselmann Guido , Kleinschmidt Andreas
Published: October 2009

Recent studies have shown that ongoing activity fluctuations influence trial-by-trial perception of identical stimuli. Some brain systems seem to bias toward better perceptual performance and others toward worse. We tested whether these observations generalize to another as of yet unassessed sensory modality, audition, and a nonspatial but memory-dependent paradigm. In a sparse event-related functional magnetic resonance imaging design, we investigated detection of auditory near-threshold stimuli as a function of prestimulus baseline activity in early auditory cortex as well as several distributed networks that were defined on the basis of resting state functional connectivity. In accord with previous studies, hits were associated with higher prestimulus activity in related early sensory cortex as well as in a system comprising anterior insula, anterior cingulate, and thalamus, which other studies have related to processing salience and maintaining task set. In contrast to previous studies, however, higher prestimulus activity in the so-called dorsal attention system of frontal and parietal cortex biased toward misses, whereas higher activity in the so-called default mode network that includes posterior cingulate and precuneus biased toward hits. These results contradict a simple dichotomic view on the function of these two latter brain systems where higher ongoing activity in the dorsal attention network would facilitate perceptual performance, and higher activity in the default mode network would deteriorate perceptual performance. Instead, we show that the way in which ongoing activity fluctuations impact on perception depends on the specific sensory (i.e., nonspatial) and cognitive (i.e., mnemonic) context that is relevant.
Exaggerated Response of a Vasopressin–Enhanced Green Fluorescent Protein Transgene to Nociceptive Stimulation in the Rat
Authors: Suzuki Hitoshi , Kawasaki Makoto , Ohnishi Hideo , Otsubo Hiroki , Ohbuchi Toyoaki , Katoh Akiko , Hashimoto Hirofumi , Yokoyama Toru , Fujihara Hiroaki , Dayanithi Govindan , Murphy David , Nakamura Toshitaka , Ueta Yoichi
Published: October 2009

Nociceptive stimulation elicits neuroendocrine responses such as arginine vasopressin (AVP) release as well as activation of the hypothalamo-pituitary-adrenal axis. We have generated novel transgenic rats expressing an AVP–enhanced green fluorescent protein (eGFP) fusion gene, and we examined the effects of nociceptive stimulation on transgene expression in the hypothalamus after subcutaneous injection of saline or formalin into the bilateral hindpaws in these rats. We have assessed (1) AVP levels in plasma and the changes of eGFP mRNA and AVP heteronuclear RNA (hnRNA) in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) usingin situhybridization histochemistry, (2) gene expression changes in distinct magnocellular and parvocellular divisions of the PVN, (3) eGFP fluorescence in the SON, the PVN, the median eminence (ME), and the posterior pituitary gland (PP). Plasma AVP levels were significantly increased 15 min after formalin injection. In the same time period, the AVP hnRNA levels in the PVN were increased, especially in the parvocellular division of the PVN in formalin-injected rats. In the same region, eGFP mRNA levels after formalin injection were also significantly increased to a much greater extent than those of AVP hnRNA. The eGFP fluorescence in the SON, the PVN, the ME, and the PP was markedly increased in formalin-injected rats and especially increased in the parvocellular divisions of the PVN. Together, our results demonstrate robust and rapid changes in the expression of the AVP-eGFP transgene in the rat hypothalamus after acute nociceptive stimulation.
The Development of the Thalamic Motor Learning Area Is Regulated by Fgf8 Expression
Authors: Martinez-Ferre Almudena , Martinez Salvador
Published: October 2009

Habenular nuclei play a key role in the control of motor and cognitive behavior, processing emotion, motivation, and reward values in the brain. Thus, analysis of the molecular and cellular mechanisms underlying the development and evolution of this region will contribute to a better understanding of brain function. TheFgf8gene is expressed in the dorsal midline of the diencephalon, close to the area in which the habenular region will develop. Given that Fgf8 is an important morphogenetic signal, we decided to investigate the role of Fgf8 signaling in diencephalic development. To this end, we analyzed the effects of altered Fgf8 expression in the mouse embryo, using molecular and cellular markers. Decreasing Fgf8 activity in the diencephalon was found to be associated with dosage-dependent alterations in the epithalamus: the habenular region and pineal gland are reduced or lacking inFgf8hypomorphic mice. Actually, our findings indicate thatFgf8may be the master gene for these diencephalic domains, acting as an inductive and morphogenetic regulator. Therefore, the emergence of the habenular region in vertebrates could be understood in terms of a phylogenetic territorial addition caused byde novoexpression ofFgf8in the diencephalic alar plate. This region specializes to permit the development of adaptive control of the motor function in the vertebrate brain.
T-Type Calcium Channel Inhibition Underlies the Analgesic Effects of the Endogenous Lipoamino Acids
Authors: Barbara Guillaume , Alloui Abdelkrim , Nargeot Joël , Lory Philippe , Eschalier Alain , Bourinet Emmanuel , Chemin Jean
Published: October 2009

Lipoamino acids are anandamide-related endogenous molecules that induce analgesia via unresolved mechanisms. Here, we provide evidence that the T-type/Cav3 calcium channels are important pharmacological targets underlying their physiological effects. Various lipoamino acids, includingN-arachidonoyl glycine (NAGly), reversibly inhibited Cav3.1, Cav3.2, and Cav3.3 currents, with potent effects on Cav3.2 [EC50∼200 nmforN-arachidonoyl 3-OH-γ-aminobutyric acid (NAGABA-OH)]. This inhibition involved a large shift in the Cav3.2 steady-state inactivation and persisted during fatty acid amide hydrolase (FAAH) inhibition as well as in cell-free outside-out patch. In contrast, lipoamino acids had weak effects on high-voltage-activated (HVA) Cav1.2 and Cav2.2 calcium currents, on Nav1.7 and Nav1.8 sodium currents, and on anandamide-sensitive TRPV1 and TASK1 currents. Accordingly, lipoamino acids strongly inhibited native Cav3.2 currents in sensory neurons with small effects on sodium and HVA calcium currents. In addition, we demonstrate here that lipoamino acids NAGly and NAGABA-OH produced a strong thermal analgesia and that these effects (but not those of morphine) were abolished in Cav3.2 knock-out mice. Collectively, our data revealed lipoamino acids as a family of endogenous T-type channel inhibitors, suggesting that these ligands can modulate multiple cell functions via this newly evidenced regulation.
In VivoRole of a Potassium Channel-Binding Protein in Regulating Neuronal Excitability and Behavior
Authors: Shahidullah Mohammad , Reddy Smitha , Fei Hong , Levitan Irwin B.
Published: October 2009

Molecular details of ion channel interactions with modulatory subunits have been investigated widely in transfected cells, but the physiological roles of ion channel modulatory protein complexes in native neurons remain largely unexplored. TheDrosophilalarge-conductance calcium-activated potassium channel (dSlo) binds to and is modulated by its binding partner Slob. We have constructed flies in which Slob expression is manipulated by P-element mutagenesis, or by transgenic expression of Slob protein or Slob-RNAi.In vivorecordings of both macroscopic and single dSlo channel currents in identified neurosecretory neurons in the pars intercerebralis (PI) region of theDrosophilabrain reveal that whole-cell potassium current and properties of single dSlo channels are modulated by Slob expression level. Furthermore, Slob genotype influences action potential durationin vivo. This unprecedented combination of current-clamp, macroscopic-current, and single-channel recordings from neurons in brains of living flies defines a critical role for an ion channel modulatory protein complex in the control of neuronal excitability. We show further that Slob-null flies exhibit significantly longer lifespan than controls under conditions of complete food deprivation. Crosses with deficiency lines demonstrate that this enhanced resistance to starvation-induced death maps close to thesloblocus. Together, these results indicate that Slob may serve a novel regulatory function in feeding behavior, possibly by influencing the excitability of the PI neurons.
Disruption of the Axon Initial Segment Cytoskeleton Is a New Mechanism for Neuronal Injury
Authors: Schafer Dorothy P. , Jha Smita , Liu Fudong , Akella Trupti , McCullough Louise D. , Rasband Matthew N.
Published: October 2009

Many factors contribute to nervous system dysfunction and failure to regenerate after injury or disease. Here, we describe a previously unrecognized mechanism for nervous system injury. We show that neuronal injury causes rapid, irreversible, and preferential proteolysis of the axon initial segment (AIS) cytoskeleton independently of cell death or axon degeneration, leading to loss of both ion channel clusters and neuronal polarity. Furthermore, we show this is caused by proteolysis of the AIS cytoskeletal proteins ankyrinG and βIV spectrin by the calcium-dependent cysteine protease calpain. Importantly, calpain inhibition is sufficient to preserve the molecular organization of the AIS bothin vitroandin vivo. We conclude that loss of AIS ion channel clusters and neuronal polarity are important contributors to neuronal dysfunction after injury, and that strategies to facilitate recovery must preserve or repair the AIS cytoskeleton.
The Time Course of Dopamine Transmission in the Ventral Tegmental Area
Authors: Ford Christopher P. , Phillips Paul E. M. , Williams John T.
Published: October 2009

Synaptic transmission mediated by G-protein coupled receptors (GPCR) is not generally thought to be point-to-point. To determine the extent over which dopamine signals in the midbrain, the present study examined the concentration and time course of dopamine that underlies a D2-receptor IPSC (D2-IPSC) in the ventral tegmental area. Extracellular dopamine was measured electrochemically while simultaneously recording D2-IPSCs. The presence of dopamine was brief relative to the IPSC, suggesting that G-protein dependent potassium channel activation determined the IPSC time course. The activation kinetics of D2receptor-dependent potassium current was studied using outside-out patch recordings with rapid application of dopamine. Dopamine applied at a minimum concentration of 10 μmfor a maximum of 100 ms mimicked the IPSC. Higher concentrations applied for as little as 5 ms did not change the kinetics of the current. The results indicate that both the intrinsic kinetics of G-protein coupled receptor signaling and a rapidly rising high concentration of dopamine determine the time course of the IPSC. Thus, dopamine transmission in the midbrain is more localized then previously proposed.
Spatiotemporal Distortions of Visual Perception at the Time of Saccades
Authors: Binda Paola , Cicchini Guido Marco , Burr David C. , Morrone M. Concetta
Published: October 2009

Both space and time are grossly distorted during saccades. Here we show that the two distortions are strongly linked, and that both could be a consequence of the transient remapping mechanisms that affect visual neurons perisaccadically. We measured perisaccadic spatial and temporal distortions simultaneously by asking subjects to report both the perceived spatial location of a perisaccadic vertical bar (relative to a remembered ruler), and its perceived timing (relative to two sounds straddling the bar). During fixation and well before or after saccades, bars were localized veridically in space and in time. In different epochs of the perisaccadic interval, temporal perception was subject to different biases. At about the time of the saccadic onset, bars were temporally mislocalized 50–100 ms later than their actual presentation and spatially mislocalized toward the saccadic target. Importantly, the magnitude of the temporal distortions co-varied with the spatial localization bias and the two phenomena had similar dynamics. Within a brief period about 50 ms before saccadic onset, stimuli were perceived with shorter latencies than at other delays relative to saccadic onset, suggesting that the perceived passage of time transiently inverted its direction. Based on this result we could predict the inversion of perceived temporal order for two briefly flashed visual stimuli. We developed a model that simulates the perisaccadic transient change of neuronal receptive fields predicting well the reported temporal distortions. The key aspects of the model are the dynamics of the “remapped” activity and the use of decoder operators that are optimal during fixation, but are not updated perisaccadically.
Neural Correlates of Consonance, Dissonance, and the Hierarchy of Musical Pitch in the Human Brainstem
Authors: Bidelman Gavin M. , Krishnan Ananthanarayan
Published: October 2009

Consonant and dissonant pitch relationships in music provide the foundation of melody and harmony, the building blocks of Western tonal music. We hypothesized that phase-locked neural activity within the brainstem may preserve information relevant to these important perceptual attributes of music. To this end, we measured brainstem frequency-following responses (FFRs) from nonmusicians in response to the dichotic presentation of nine musical intervals that varied in their degree of consonance and dissonance. Neural pitch salience was computed for each response using temporally based autocorrelation and harmonic pitch sieve analyses. Brainstem responses to consonant intervals were more robust and yielded stronger pitch salience than those to dissonant intervals. In addition, the ordering of neural pitch salience across musical intervals followed the hierarchical arrangement of pitch stipulated by Western music theory. Finally, pitch salience derived from neural data showed high correspondence with behavioral consonance judgments (r= 0.81). These results suggest that brainstem neural mechanisms mediating pitch processing show preferential encoding of consonant musical relationships and, furthermore, preserve the hierarchical pitch relationships found in music, even for individuals without formal musical training. We infer that the basic pitch relationships governing music may be rooted in low-level sensory processing and that an encoding scheme that favors consonant pitch relationships may be one reason why such intervals are preferred behaviorally.
Aging and Political Participation in Japan: The Dankai Generation in a Political Swing
Authors: Takao Yasuo
Published: October 2009

Population aging is not just the socioeconomic issue of Japan's future, but the political issue as well. The sharing of resources for an aging society will reshape policy strategies and democracy-building. This article will examine the direction and nature of participation by the elderly in the political process of Japanese society.
Skins, Tattoos, and Susceptibility
Authors: Cheng Anne Anlin
Published: October 2009

This essay tells the story of the performer Josephine Baker and the architect Adolf Loos as a way to track an unexpectedly intimate dialogue between the making of the so-called "denuded modern surface" and the spectacle of black skin at the turn of the twentieth century. This connection in turn compels a reconsideration of the way we read (as) modern subjects.
THE EXCRETION OF HORMONES IN CASES OF HYDATIDIFORM MOLE AND CHORIONEPITHELIOMA
Authors: Frandsen V. Aasted , Stakemann G.
Published: October 2009

The urinary excretion of gonadotrophin, oestrogens and pregnanediol has been estimated in ten patients with hydatidiform mole and in three female patients with chorionepithelioma. In all 13 cases an incieased excretion of gonadotrophin was found. The excretion of pregnanediol (investigated in seven patients only) was of the same magnitude as in nonpregnant women except in one case, where a slightly increased excretion was found. The excretion of oestrogens was low; one case of mole and two of chorionepithelioma excreted amounts at the non-pregnant level, whereas most of the remainders excreted amounts much lower than in normal pregnancies of a corresponding gestational length. Two patients, however, excreted amounts comparable to those of a normal pregnancy. As the ratio oestriol: oestrone + oestradiol was at the non-pregnant level, the oestrogens excreted by patients with hydatidiform mole and chorionepithelioma are assumed to have been produced by the ovaries of the woman strongly stimulated by the enormous amounts of gonadotrophin present.
BREEDING OF XENOPUS LAEVIS DAUDIN
Authors: Henriques U.
Published: October 2009

A method for breeding Xenopus laevis Daudin is reported. This method has proved reliable for regular and frequent breeding throughout the year.
PROTECTION BY RESTRAINT AGAINST PARATHYROID HORMONE INTOXICATION
Authors: Selye H. , Tuchweber B. , Gabbiani G.
Published: October 2009

In the rat, forced immobilization on a board can offer complete protection against the osteitis fibrosa as well as the cardiovascular and renal calcification normally produced by large doses of parathyroid extract.
KLINEFELTER'S SYNDROME, A CLINICAL AND CYTOGENIC STUDY IN TWENTY-FOUR CASES
Authors: Zuppinger Klaus , Engel Eric , Forbes Anne P. , Mantooth Linda , Claffey Jane
Published: October 2009

Clinical and cytogenetic studies were made of twenty four patients with Klinefelter's syndrome in order to determine the somatic consequences of X chromosomal overdosage and its effect on the incidence of metabolic and degenerative diseases. Salient features of the group were tall stature, obesity, a high incidence of diabetes mellitus, hyperlipemia, hypercholesterolemia, gall bladder disease, chronic pulmonary infection, peptic ulcer, varicose veins, laboratory indices of hypothyroidism and a disordered personality. There was a striking absence of hypertension, myocardial infarction and rheumatoid arthritis and no case of hyperthyroidism, thyroiditis or gout. Family histories revealed a high incidence of diabetes mellitus in close relatives.

Thus the second X chromosome, although it is sequestered in adult life appears to have profound metabolic as well as morphological effects.
RADIOIMMUNOASSAYS EMPLOYING IMMUNOSORBENTS
Authors: Wide Leif
Published: October 2009

The use of a reaction between compounds in a two phase system – a solid phase and a liquid phase – has simplified the technical procedure of the radioimmunoassays. Antigens or antibodies can be coupled covalently to insoluble polymers to form stable conjugates with retention of immunological binding capacity. Such immunosorbents can be used in radioimmunoassays in many different ways and with the solid phase in different forms. Some of these techniques seem to be universally applicable for the assay of antigens or antibodies. In one of these, antigens or antibodies are chemically coupled to cyanogen bromide activated insoluble polysaccharides in a particle form. This method which has several advantages when compared with most other radioimmunological methods is discussed in particular. Finally, a detailed description of the preparation of an immunosorbent and its use in such a radioimmunoassay system is given.
RADIOIMMUNOASSAY WITH ANTIBODY-COATED DISCS AND TUBES
Authors: Catt K. J.
Published: October 2009

The measurement of polypeptide hormones by radioimmunoassay has been facilitated by the introduction of solid-phase antibody preparations which permit the separation of bound and free tracer to be performed by a rapid washing step. The solid-phase radioimmunoassay technique originally employed substituted powders as the solid-phase, and more recently, antibody-coated discs and tubes have been used. The observation that standard plastic tubes would adsorb an appropriate quantity of antibody for use in radioimmunoassay has allowed the development of an extremely simple method, in which the assay is performed in plastic counting tubes coated with specific antibody. Antibody-coated tube assays have been established for the measurement of HGH, HCS, HLH, ovine LH, ovine prolactin and other hormones. Recent observations on the use of coated-tube assays for the estimation of gonadotrophic hormones in human and ovine plasma are described, and the temporal relationship between oestrogen secretion and LH release is presented.

The coated-tube assay procedure is simple, rapid and reliable, and is of general application to the assay of ligands such as antigens, steroids and other molecules with specific binding proteins.
SOLID-PHASE RADIOIMMUNOASSAY OF ESTROGENS IN BIOLOGICAL FLUIDS
Authors: Abraham G. E. , Odell W. D. , Edwards R. , Purdy J. M.
Published: October 2009

Using antibody-coated test tubes as a detection method, three types of assay for 17β-estradiol (E2) have been investigated. Method A involved the measurement of E2 in the dried ether extract of biological fluids. Method B required a chromatographic step after ether extract, prior to measurement of E2. Method C (direct method) measured E2 directly in the biological fluid, diluted with assay buffer. Method C was found reliable for the measurement of E2 in human follicular fluid, but not in pregnancy serum. Method A was adequate for pregnancy serum, but overestimated E2 in serum from normal adult male and female subjects. Method B was reliable to measure E2 in all the biological fluids tested.
CLONAL LINES OF HUMAN CHORIOCARCINOMA CELLS IN CULTURE
Authors: Kohler P. O. , Bridson W. E. , Hammond J. M. , Weintraub B. , Kirschner M. A. , Van Thiel D. H.
Published: October 2009

Six clonal lines of human choriocarcinoma cells, isolated by the single cell plating technique, have been maintained in culture for over two years. These clones have been examined for expression of tissue-specific function. Individual clonal lines have retained the capacity to synthesize human chorionic gonadotrophin (HCG), human chorionic somatomammotrophin (HCS), and progesterone, and also to transform steroid precursors to oestrone and oestradiol. The HCG species produced by different clones have different biologic to immunologic potency ratios ranging from 0.5 to 2.0 which are constant within any particular clone. HCG synthesized in culture has been examined by polyacrylamide gel electrophoresis and isoelectric focusing and had approximately the same molecular size as a highly purified urinary HCG preparation, but a different net charge at an acid pH.
MEASUREMENT OF FLOW IN PERFUSED ORGANS, USING MICROSPHERE TECHNIQUES
Authors: Rudolph Abraham M. , Heymann Michael A.
Published: October 2009

Injection of radionuclide labelled microspheres into the circulation of animals can be used to measure the proportion of blood flow to any organ, or the regional distribution of blood flow within any organ. The use of this technique depends on the fact that these microspheres are distributed according to the blood flow and that they are completely trapped within the organ. It is important that they are adequately mixed within the flowing stream and also evenly distributed at branching sites. It has been shown that for the assessment of the regional distribution within an organ, microspheres of small diameter (10–15 μm) are preferable since they more accurately reflect true flow to all segments of the organ. The accurate measurement of the distribution of flow is also dependent on the absolute number of microspheres present in any organ or segment of organ under study.

Studies of regional distribution of flow during cardio-pulmonary bypass in rhesus monkeys have shown that the proportion of cardiac output distributed to the kidneys falls, while that to the gut increases. The haematocrit of the perfusing blood may modify the distribution of flow to organs; thus, cerebral blood flow was maintained while using blood of low haematocrit whereas with normal haematocrit it fell during perfusion. The regional distribution of the blood flow within the kidney has been shown to change markedly with artificial perfusion in situ with a striking increase in flow to the medulla and inner cortex during perfusion as compared to normal.
TRANSCAPILLARY EXCHANGE OF PROTEIN-BOUND HORMONES FROM THE BLOODSTREAM INTO THE TISSUE FLUID
Authors: Simpson-Morgan M. W. , Irvine C. H.
Published: October 2009

The transcapillary exchange of protein-bound for measuring this exchange are discussed. methods to the study of the transcapillary described, and the usefulness of the methods for a study of transcapillary exchange of protein-bound steroid hormones considered. ligands and methods useful The application of these exchange of thyroxine is
THE BASIC PROTEINS OF TROUT TESTIS CHROMATIN: ASPECTS OF THEIR SYNTHESIS, POST-SYNTHETIC MODIFICATIONS AND BINDING TO DNA
Authors: Dixon Gordon H.
Published: October 2009

Spermatogenesis in rainbow trout provides a favourable system for the study of the striking changes in the population of basic nuclear proteins in the chromatin of the developing sperm. Methods are described for the isolation and characterization of the basic proteins of testis both on the preparative and the micro-scale. Large volume changes occur as cells pass through the series of developmental changes and they may be readily separated by velocity sedimentation at one gravity. This enables a study to be made of the timing of particular biochemical events during development. The process whereby the histones are removed and replaced by newly synthesized protamines is examined in detail and possible mechanisms discussed. The role of post-synthetic modification of basic proteins by phosphorylation and acetylation is examined and the sites of these modifications in the primary sequence of protamine and histones determined. From a study of the timing of the modification reactions, it appears that phosphorylation and acetylation play an important role in modulating the correct binding of highly basic regions of histones to DNA while acetylation may also be involved in de-stabilizing the tight complexes between DNA and the basic NH2-terminal regions of histones IIb1, IIb2, III and IV as a preliminary to their replacement by protamine and the formation of the very compact nucleo-protamine of the mature sperm.
DEGRADATION OF MESSENGER RNA IN MAMMALIAN CELLS
Authors: Kenney Francis T. , Lee Kai-Lin , Stiles Charles D.
Published: October 2009

Analyses of the response of hydrocortisone-induced tyrosine transaminase in cultured H-35 cells to inhibitors of translation (cycloheximide, puromycin) suggest: (1) that bound ribosomes stabilize messenger RNA in vivo; (2) that messenger is degraded at a rate determined by the rate of translation. Since specific messenger RNAs of mammalian cells are degraded at quite different rates, there may be extensive heterogeneity either in the rate at which ribosomes traverse different messengers or in the number of ribosomes which translate specific messenger RNAs.
BIOCHEMICAL MECHANISM TO CONTROL PROTEIN SYNTHESIS mRNA SPECIFIC INITIATION FACTORS
Authors: Revel M. , Groner Y. , Pollack Y. , Cnaani D. , Zeller H. , Nudel U.
Published: October 2009

Studies with cell fre systems of protein synthesis have shown that mRNAs are not translated uniformly by ribosomes. In particular the existence of mRNA specific initiation factors which stimulate or inhibit the translation of individual cistrons is now well recognized. We originally reported that E. coli initiation factor IF3 activity can be separated into subfractions differing in their activity toward MS2 and T4 mRNA. Our recent work, however, indicates that the specificity of IF3 for mRNAs actually results from its combination with "interference" protein factors. These proteins act in the presence of IF3 to stimulate the translation of certain cistrons while inhibiting that of others. We have isolated three interference factors from E. coli and characterized some of their cistron specificities on MS2 RNA, T4 and T7 early and late mRNAs. These factors can explain the heterogeneity of IF3 toward various mRNA. In vivo variations in the activity of ribosomes can result from changes either in IF3 or in an interference factor.

We have also recently purified a mRNA-specific initiation factor from mammalian cells. This factor isolated from the ribosomal wash of rabbit reticulocytes stimulates haemoglobin mRNA translation but not that of Mengo virus RNA, in a crude extract from Krebs ascites cells. This factor stimulates a globin synthesis. Ribosome activity may be, therefore, regulated both quantitatively and qualitatively by such factors.
CONTROL MECHANISMS OF STEROID HORMONE RECEPTORS IN THE REPRODUCTIVE TRACT
Authors: Milgrom E. , Thi M. Luu , Baulieu E. E.
Published: October 2009

The hormonal control of the amount of steroid receptors in the target cells may be a clue for the understanding of hormone receptivity and of integrated hormonal mechanisms (for example cyclic sequences of events). As a model system, the guinea pig uterus progesterone receptor has been studied. After an analysis of the theoretical and practical parameters which should be taken into account in order to measure specifically the receptor binding sites, the protein-RNA synthesis mediated induction of the progesterone receptor by oestradiol is described. The half life of the receptor is about 5 days in hormone deprived animals (in vivo experiments), but in case of progesterone administration it decays very rapidly, due probably to a rise in inactivation rate. Sequential administration of oestradiol and progesterone reproduces the changes observed during the oestrous cycle. The mechanism of the apparent inactivation of the receptor after binding of its own hormonal ligand is unknown.

Some information available about the hormonal control of the androgen and oestrogen receptors in their respective target organs is reviewed.
THE USE OF DOGS FOR STUDIES OF TOXICITY OF CONTRACEPTIVE HORMONES
Authors: Hill Robert , Dumas Kenneth
Published: October 2009

Responses to endogenous and exogenous sex steroids in the dog are characteristic for that species, differing in many important aspects from other laboratory animals and man.

Long-term administration to dogs of progesterone and synthetic compounds structurally related to this natural gestagen has resulted in precocious development of mammary gland tumours and other changes suggesting stimulation of anterior pituitary activity. Progestogens structurally related to testosterone have not induced similar effects.

Results obtained to date indicate a lack of relevance of data obtained in the dog to the prediction of clinical potential of sex steroids for mammary gland carcinogenesis.
SOME METABOLIC ACTIONS AND POSSIBLE TOXIC EFFECTS OF HORMONAL CONTRACEPTIVES IN ANIMALS AND MAN
Authors: Drill Victor A.
Published: October 2009

Data on contraceptive steroids derived from properly conducted and interpreted animal studies can serve to predict effects that may be expected to occur in women. Important also is the absence of certain effects of the steroids in both animals and man. Since the drugs are for human use it is necessary that adequate clinical studies be conducted to confirm the predictions made regarding effectiveness and safety. Selected topics of importance are discussed to summarize our knowledge in specific areas and to illustrate correlations between the effects of contraceptive steroids in animals and in women.
U. S. FOOD AND DRUG ADMINISTRATION REQUIREMENTS FOR TOXICITY TESTING OF CONTRACEPTIVE PRODUCTS
Authors: Berliner V. R.
Published: October 2009

The evolution of toxicity testing of drugs in general, before and after the enactment of the Kefauver-Harris Amendments of 1962 to the Food, Drug and Cosmetic Act of 1938, and of the specialized requirements for test methodology to support the safety of systemic contraceptives are described, with comments on the organizational mechanisms for their implementation, for the interpretation of test results and for eventual regulatory actions and policies. The controversial long-range (life-time) studies in beagles and rhesus monkeys for hormonal contraceptives to predict their carcinogenic potentials are discussed. Results already obtained from these ongoing investigations suggest a hypothesis that in those hormonal contraceptives which are capable of inducing "atypical" nodules and/or malignant tumours in mammary glands of beagles it might be their chemical configurations that exert this reaction, along with their progestogenic potency.

Since the contraceptive compounds exhibiting these adverse properties in beagles have not been used long enough clinically to determine their carcinogenic or tumorigenic potential in humans, it is not possible to correlate these effects in the beagle to that in the human for these compounds. On the other hand, for OC's which have been approved for marketing and have been in wide and long clinical usage in the United States, no hazard in terms of increased tumorigenic or carcinogenic potential has been identified to date for the human and the beagle.

While metabolism studies with those contraceptive formulations that were incriminated by their adverse actions in beagles have disclosed metabolic patterns and endproducts to be different in the beagle and human, a causative relationship between their metabolic endproducts and a tumorigenie and carcinogenic effect, especially with prolonged administration of these contraceptive compounds, has not been investigated.

With these considerations, and because the suitability of the rhesus monkey as an animal model for carcinogenicity testing is questioned, it would be contrary to the spirit and intent of the existing drug safety regulations in the United States to eliminate the canine species as a test animal in carcinogenicity investigations to support the safety of hormonal contraceptives.

Tentative guidelines for toxicity tests on new and forthcoming principles for contraception such as the prostaglandins, and IUD's serving as carriers of pharmacologically active substances, have been drawn up in consultation with advisory committees and will be discussed.
SPECIAL REQUIREMENTS FOR TOXICOLOGICAL TESTING OF METAL-RELEASING INTRAUTERINE DEVICES
Authors: McConnell Robert Gordon
Published: October 2009

Intrauterine devices (IUD's), intrauterine drug reservoirs (IUDR's), and metal-releasing intrauterine drug reservoirs (MR-IUDR's) with antifertility activity in the animal and human are considered as separate entities. General requirements for toxicologic and teratologic testing of such agents in animals are presented. A comparison reveals the relative advantages and disadvantages of simian, canine, lagomorph, and rodent species. A pretreatment review of obstetric-gynaecologic status and history of each animal is emphasized. Designing of appropriate replicas of the clinical device for use in predictive animal studies requires comparative data on uterine morphology, device-endometrium spatial relationships, and drug release rates. Adult, maternal and foetal tissue metal levels may be important; the analytical methods for detecting and localizing cellular and subcellular wet tissue metal levels are available. Existing in vivo mutagenicity assay procedures are poorly adapted to intrauterine drug testing. Method modifications are explored briefly. A sequence for the animal safety testing of an intrauterine antifertility agent, and its interrelation with clinical research, is outlined.
CELLULAR BASIS OF THE IMMUNE RESPONSE
Authors: Miller J. F. A. P.
Published: October 2009

Lymphocytes, the cells competent to initiate immune responses, can be divided into two major groups: thymus-derived or T cells responsible for "cellular immunity" (e. g. delayed hypersensitivity reactions) and bursa (or bursa-equivalent) derived or B cells which produce immunoglobulin (antibody) molecules and are involved in "humoral immunity". "Accessory" cells, such as monocytes (or macrophages), polymorphonuclear leucocytes and mast cells act in an auxiliary manner by facilitating antigen processing or presentation, or by liberating factors which modify the various manifestations of the immune response.

A variety of interactions between T and B cells and between lymphocytes and accessory cells have been described in both cellular and humoral immunity. Antigen-activated T cells produce factors with various activities: some are involved in recruiting inflammatory cells, others activate macrophages and enhance their microbicidal activities, and others modify B-cell responsiveness either by facilitating or suppressing it. These factors are instrumental in T-cell regulation of immune responsiveness. Antibody produced by B cells also plays a role in immunoregulation, acting either as an immunopotentiating influence or as a negative feedback, e. g. when complexed with antigen, turning off the response of T or B cells. A detailed knowledge of the precise manner in which cells involved in immunity are regulated is essential for an understanding of how the foetus, an essentially "foreign transplant", can survive to term in its immunologically mature "alien" host.
STRUCTURE AND FUNCTION OF IMMUNOGLOBULINS
Authors: Franklin Edward C.
Published: October 2009

There are five major classes of immunoglobulins – IgG, M, A, D and E. Each is made of two heavy and two light chains or polymers of this basic subunit. The structure of each heavy and light chain consists of a variable region involved in antigen specificity and binding and a constant region which is involved in the class specific properties.

The different classes of immunoglobulins differ in the biological properties. Of particular interest is the IgA fraction which provides antibodies in all the external secretions – including the reproductive organs. A few speculations are offered as to the possible role of IgA in reproductive biology.
KINETICS OF ANTIBODY FORMATION AND REGULATORY ASPECTS OF IMMUNITY
Authors: Nossal G. J. V.
Published: October 2009

This paper, which is to be read in conjunction with that of Dr. J. F. A. P. Miller earlier in this volume, addresses itself to the kinetics of antibody production and to the regulation of the immune response. It is divided into four main sections. The first examines the kinetics of antibody production to a single, strong challenge injection of antigen. The cellular events involved in the latent period and the subsequent exponential phase of antibody production are examined from the viewpoint of four key concepts: triggering, clonal expansion, IgM to IgG switch and affinity maturation.

The second section examines the major regulatory influences and feedback loops in immunity. Antigen is discussed as an agent capable of causing tolerance as well as triggering. Antibody is considered an important regulator, and the mechanisms of IgM-positive feedback, IgG-negative feedback, and tolerance and blockade effects of immune complexes are outlined. Immunological memory, the opposite phenomenon to tolerance, is briefly described, as is the importance of genetic factors.

The third sections looks at more complex models of the immune response, and in particular at the lessons to be learnt from tumour progression.

The importance of three different kinds of cell-mediated killing is discussed, as is the combinatorial influence of B and T cell activation. Attention is drawn to the reasons for believing that tumour progression eventually will lead to immunological non-reactivity, and to the fact that there are analogies between growth of tumours, starting from a single cell, and growth of foetuses.

The fourth section finally poses the question of the immunological privilege of the developing foetus. While there are more questions than answers in this field, anatomical barriers and antigen as a blocking factor probably both play important roles.
EFFECTS OF IMMUNIZATION WITH LDH-X ON FERTILITY
Authors: Goldberg Erwin
Published: October 2009

Immunological regulation of fertility can be best achieved if a defined macromolecule is used to provide the antigenic stimulus. Proteins with known enzymatic properties are attractive molecules in this area if it can be demonstrated unequivocally that they are unique constituents of spermatozoa, and are completely foreign to the female. This paper describes immunosuppression of fertility by the sperm-specific isozyme of lactate dehydrogenase (LDH-X). In addition, evidence is reviewed which suggests that acrosomal proteinase and hyaluronidase may be unique to sperm. Data are presented which confirm the sperm specificity of LDH-X and the immunochemical homogeneity of purified preparations of this isozyme.

Immunization of female rabbits with LDH-X significantly reduces the fertility of these animals. Experimental results indicate that the primary effect of immunization involves blockage of fertilization. While those ova which are fertilized in an immune environment develop and implant normally, there is a high rate of post-implantation embryo mortality. Rabbit blastocysts transferred to immune recipients implant at the same rate as in non-immune controls. These findings are consistent with the conclusion that the developing embryo must interact with antibody during the pre-implantation stages of pregnancy when antigenic sites conferred by the sperm LDH-X are available. Such interaction can be demonstrated directly by immunofluorescence techniques.