Glycinamide, a glycine pro-drug, induces antinociception by intraperitoneal or oral ingestion in ovariectomized rats.

AIMS: The effect of i.p. injection or oral ingestion of glycinamide, a glycine pro-drug, on two tests for nociception was assessed in ovariectomized Sprague Dawley rats. MAIN METHODS: To explore the potential analgesic effect of glycinamide the vocalization threshold to tail shock (VT) and the tail flick latency (TFL) were used. Glycinamide was administered both through the intraperitoneal route (doses 0, 25, 100, 400, 800 mg/kg) and through ad libitum oral ingestion of glycinamide solution (40 mg/ml) following a 24h period of water deprivation. KEY FINDINGS: Glycinamide exerted a significant analgesic effect on VT when injected i.p. at doses of 400 or 800 mg/kg. Analgesia occurred 10-20 min post-injection and persisted approx 45 min. At the high dose level, glycinamide exerted a weaker and more delayed effect on TFL than on the VT test. I.p. injection of 800 mg/kg glycinamide inhibited vocalizations induced by the application of suprathreshold tail shocks (30% above threshold) with a latency of approx 3 min and duration of approx 1h. The volume of a glycinamide solution (40 mg/ml) ingested by rats deprived of water for 24h was positively correlated with the degree of analgesia in the VT test. Values between 100 and 200mg glycinamide exerted clear analgesic responses. SIGNIFICANCE: Thus, glycinamide, either by systemic or oral routes, exerts a clear analgesic effect in the VT test of nociception and a much weaker action in the TFL test. This effect is probably due to the conversion of glycinamide to glycine in the brain.

Corticosteroids impair remyelination in the corpus callosum of cuprizone-treated mice.

Corticosteroids (CS) are effective in the treatment of many brain disorders, such as multiple sclerosis (MS) or traumatic brain injury. This has been scrutinised in different experimental animal models. However, neither the mechanisms, nor the site of CS action are fully understood. Short-term high-dose CS treatment improves MS symptoms and severity of clinical disability during an acute inflammatory exacerbation of disease. In the present study, we analysed the influence of CS on the expression of cellular and molecular markers of spontaneous endogenous remyelination in the toxic non-immune cuprizone animal model at early (9 days) and intermediate (21 days) remyelination, as well as steroidal effects in primary astrocytes and oligodendrocyte progenitor cultures. Dexamethasone (Dex) and methylprednisolone (MP) induced a higher expression of the differentiation markers myelin basic protein and proteolipid protein (PLP) in cultured oligodendrocyte progenitor cells (OPC). CS exposure of primary cultured astrocytes resulted in a greater expression of those genes involved in OPC proliferation [fibroblast growth factor 2 (FGF2) and platelet-derived growth factor (PDGF)-αα] and a reduced expression of the pro-maturation factor insulin-like growth factor 1. Pro-maturating effects of CS were completely blocked by FGF2 and PDGF-αα co-application in OPC cultures. MP treatment in vivo resulted in a reduced recovery of PLP-staining intensity, whereas the re-population of the demyelinated corpus callosum with adenomatous polyposis coli-expressing oligodendrocytes was not affected. The numbers of brain intrinsic inflammatory cells, microglia and astrocytes during remyelination were similar in placebo and MP-treated animals. Our findings suggest that treatment with CS might have, in addition to the well-known benefical effects on inflammatory processes, a negative influence on remyelination.

Differences in the perception of seven behaviour-modifying techniques in paediatric dentistry by undergraduate students using lecturing and video sequences for teaching.

Whilst preparing undergraduate students for a clinical course in paediatric dentistry, four consecutive classes (n = 107) were divided into two groups. Seven behaviour-modifying techniques were introduced: systematic desensitization, operant conditioning, modelling, Tell, Show, Do-principle, substitution, change of roles and the active involvement of the patient. The behaviour-modifying techniques that had been taught to group one (n = 57) through lecturing were taught to group two (n = 50) through video sequences and vice versa in the following semester. Immediately after the presentations, students were asked by means of a questionnaire about their perceptions of ease of using the different techniques and their intention for clinical application of each technique. After completion of the clinical course, they were asked about which behaviour-modifying techniques they had actually used when dealing with patients. Concerning the perception of ease of using the different techniques, there were considerable differences for six of the seven techniques (P < 0.05). Whilst some techniques seemed more difficult to apply clinically after lecturing, others seemed more difficult after video-based teaching. Concerning the intention for clinical application and the actual clinical application, there were higher percentages for all techniques taught after video-based teaching. However, the differences were significant only for two techniques in each case (P < 0.05). It is concluded that the use of video based teaching enhances the intention for application and the actual clinical application only for a limited number of behaviour-modifying techniques.

Cevipabulin (TTI-237): preclinical and clinical results for a novel antimicrotubule agent.

Antimitotic agents are among the most effective drugs for the treatment of solid tumors and metastatic cancer. These drugs promote cell death by interfering with the crucial structural and regulatory function of microtubules in cells. Most of the agents of clinical relevance are natural products or semisynthetic derivatives thereof, and they fall into two major classes: microtubule stabilizers such as the taxanes, which enhance tubulin polymerization, and microtubule destabilizers such as the Vinca alkaloids, which lead to the depolymerization of existing microtubules. While these drugs are effective in inhibiting the progression of certain types of tumors, their utility is limited in part by incomplete tumor responses and/or significant side effects. In addition, inherent resistance is encountered in many tumor types, or acquired resistance may occur as a result of multiple cycles of therapy. Cevipabulin (TTI-237) is a novel, small synthetic molecule with an unusual biological mode of action. It appears to bind at the vinca site, but exhibits some properties similar to those of taxane-site ligands, such as enhancing tubulin polymerization. The compound works against a variety of tumors, including those resistant to paclitaxel and vincristine. Furthermore, cevipabulin is stable and water-soluble, and can be administered i.v. or p.o. in saline. It can be synthesized in bulk quantities efficiently. Based on these properties, cevipabulin was selected for clinical development.

Application of infrared spectroscopy to monitoring gas insulated high-voltage equipment: electrode material-dependent SF(6) decomposition.

Sulfur hexafluoride is a chemically inert gas which is used in gas insulated substations (GIS) and other high-voltage equipment, leading to a significant enhancement of apparatus lifetime and reductions in installation size and maintenance requirements compared to conventional air insulated substations. However, component failures due to aging of the gas through electrical discharges may occur, and on-site monitoring for risk assessment is needed. Infrared spectroscopy was used for the analysis of gaseous by-products generated from electrical discharges in sulfur hexafluoride gas. An infrared monitoring system was developed using a micro-cell coupled to an FTIR spectrometer by silver halide fibers. Partial least-squares calibration was applied by using a limited number of optimally selected spectral variables. Emphasis was placed on the determination of main decomposition products, such as SOF(2), SOF(4), and SO(2)F(2). Besides the different electrical conditions, the material of the plane counter electrode of the discharge chamber was also varied between silver, aluminum, copper, tungsten, or tungsten/copper alloy. For the spark experiments the point electrode was the same material as chosen for the plane electrode, whereas for partial discharges a stainless steel needle was employed. Complementary investigations on the chemical composition within the solid counter electrode material by secondary neutral mass spectrometry (SNMS) were also carried out. Under sparking conditions, the electrode material plays an important role in the decomposition rates of the gas-phase, but no relevant material dependence could be observed under partial discharge conditions.

Developmental sex differences in estrogen receptor-beta mRNA expression in the mouse hypothalamus/preoptic region.

Estrogens play a significant role during mammalian brain development and are required for the masculinization of neuronal circuits involved in sex-specific behaviors and neuroendocrine functions. Cellular estrogen signalling is transmitted through nuclear estrogen receptors (ER) which are divided into two subforms: the ER-alpha as well as the recently cloned ER-beta have been demonstrated in the hypothalamus. In the present study, we have analyzed the sex-specific expression of ER-beta mRNA in the pre- and postnatal mouse hypothalamus/preoptic region (Hyp/POA) by semiquantitative RT-PCR. The ER-beta mRNA was detectable as early as embryonic day (E) 15 in the diencephalon of both sexes. In males, levels of mRNA expression in the Hyp/POA increased until birth and remained high throughout postnatal (P) development, whereas in females, such an increase was not observed. Significantly higher mRNA levels were detected in the male Hyp/POA from E17 until P15. Perinatal sex differences in ER-beta mRNA expression coincide with higher estrogen-forming rates in the male Hyp/POA. At present, no direct evidence is available which demonstrates that estrogen signalling through ER-beta is involved in brain development. However, data from our and other studies suggest a potential role for this signal transduction pathway for brain differentiation.

Developmental expression and regulation of aromatase- and 5alpha-reductase type I mRNA in the male and female mouse hypothalamus.

Androgen metabolites synthesized by neural aromatase and 5alpha-reductase are implicated in many aspects of mammalian brain development and, in particular, in the masculinization of distinct central nervous system structures and brain functions. The present study was designed to determine (1) the developmental profile of aromatase- and 5alpha-reductase type I mRNA expression in the mouse hypothalamus and (2) to relate ontogenetic sex differences in aromatase activity which have been described in the past to sex-specific aromatase gene expression. In addition, we analysed the effect of androgens on the perinatal regulation of hypothalamic aromatase and 5alpha-reductase type I mRNA expression. By applying semiquantitative reverse transcription-polymerase chain reaction analysis, we found hypothalamic aromatase mRNA expression to be developmentally regulated and to display sex differences at birth and on postnatal day 15 with higher mRNA levels in males. Newborn males and females, which were treated in utero with the androgen receptor antagonist cyproterone actetate, exhibited significantly reduced aromatase mRNA levels compared with untreated controls. In contrast to aromatase, expression levels of hypothalamic 5alpha-reductase mRNA did not reveal a clear-cut developmental profile or sex differences, and no regulatory role for androgens in controlling 5alpha-reductase mRNA expression was found. In conclusion, these results demonstrate perinatal sex differences in hypothalamic aromatase- but not 5alpha-reductase gene expression and suggest that sex differences in perinatal aromatase activity are reflected by corresponding differences in mRNA levels. Androgens are found to control brain estrogen formation pretranslationally at the level of aromatase gene expression. Our findings imply that sex differences in androgen availability and responsiveness are important regulatory factors for aromatase expression in the developing male hypothalamus.

Androgens stimulate the morphological maturation of embryonic hypothalamic aromatase-immunoreactive neurons in the mouse.

Gonadal steroids play an important role as developmental factors for the rodent brain and are implicated in the sexual differentiation of neural structures. Estrogens have been linked to survival and plasticity of central neurons, thereby regulating the development of hypothalamic and limbic structures associated with reproductive functions. Besides estrogens, androgens also contribute actively to CNS maturation. We have shown recently that androgens stimulate the receptor-mediated functional differentiation of cultured hypothalamic aromatase-immunoreactive (Arom-IR) neurons by stimulating the expression of Arom, the key enzyme in estrogen formation. In the present study, we investigated whether androgens are capable of influencing morphological differentiation of hypothalamic Arom-IR neurons. Androgen treatment, unlike estrogen, stimulated the morphological differentiation of cultured embryonic hypothalamic Arom-IR cells by increasing neurite outgrowth and branching, soma size, and the number of stem processes. This effect was brain region- and transmitter phenotype-specific; neither cortical Arom-IR neurons nor hypothalamic GABAergic neurons responded to androgens. Moreover, morphogenetic effects depended on androgen receptor (AR) activation, since morphological changes were completely inhibited by flutamide. Double-labeling of hypothalamic Arom-IR neurons revealed a considerable number of cells coexpressing AR, whereas cortical Arom-IR cells did not label for AR. Our data demonstrate that androgens function as morphogenetic signals for developing hypothalamic Arom-IR cells, thus being potentially effective in influencing plasticity and synaptic connectivity of hypothalamic Arom-systems.

Sex differentiation of rat hippocampal GABAergic neurons.

In order to analyse mechanisms of sex differentiation of the hippocampus at the cellular level, the differentiation of hippocampal GABAergic neurons was studied in vitro. Serum-supplemented and serum-free dissociated cell cultures were raised from the hippocampus of embryonic day 17 male and female rat embryos for up to 14 days in vitro. This time period roughly corresponds to the critical phase for sex differentiation of the rat brain as determined in vivo. Serum-free cultures were treated with testosterone and/or 17 beta-oestradiol for the entire culture period. Control cultures from male donors contained twice as many GABA-immunoreactive neurons as those from female donors, while there was no sex difference in overall counts of neurons stained for microtubule-associated protein 5. Measurements of high-affinity uptake of [3H]GABA essentially confirmed this sex difference. The development of the sex difference could not be influenced by long-term treatment with androgen or oestrogen. It is concluded that sex differentiation of a specific subpopulation of hippocampal neurons may take place independently of the environment provided by gonadal steroids and in the absence of extrinsic connections with the hypothalamus or other relays of the limbic circuit.

Oxytocin and vasopressin immunoreactivity in rabbit hypothalamus during estrus, late pregnancy, and postpartum.

Mother rabbits construct an elaborate maternal nest before parturition and display a single, brief, daily nursing bout throughout lactation. These features present a unique model for investigating the relevance of changes in neuroendocrine secretion associated with pregnancy and parturition for the regulation of maternal behavior. In the present study we analyzed changes in the location, somal size, and number of oxytocin (OT)- and arginine vasopressin (AVP)-immunoreactive (IR) neurons in the hypothalamus of rabbits in estrus, late pregnancy (day 29), and postpartum day 1. From estrus to late pregnancy, the number of OT-IR neurons increased in the scattered cell groups located in the lateral hypothalamic area (LHA), but not in the magnocellular nuclei, i.e., paraventricular nucleus (PVN) and supraoptic nucleus (SON). On postpartum day 1 the increase in the number of OT-IR neurons was sustained in the LHA and became apparent also in the main body of the PVN, in which the number of OT-IR neurons doubled. Increases in the somal size of OT-IR cells were seen in all three nuclei only on postpartum day 1. No OT-IR cells were found in the suprachiasmatic nucleus (SCN). From late pregnancy and into postpartum day 1 increases in the somal size of AVP-IR neurons were detected in the PVN, SON, and LHA but not in the SCN. The number of AVP-IR neurons increased between late pregnancy and postpartum day 1 in the SON only. The changes observed in OT and AVP expression in specific hypothalamic nuclei may be related to specific somatic and behavioral events occurring around the time of parturition, e.g., nest-building, maintenance of homeothermy, elevation of blood volume, and nursing in mother rabbits.

Hypothalamic distribution of astrocytes is gender-related in Mongolian gerbils.

Hypothalamic neuroglial ontogeny was examined during neonatal development of two hormone-sensitive, sex-specific nuclei, the pars compacta of the sexually dimorphic area (SDApc) and the suprachiasmatic nucleus (SCN) in the gerbil. Specific antibodies against vimentin and glial fibrillary acidic proteins (GFAP) identified neuroglia. Unbiased measures of labelled cell anatomical parameters were taken using stereomorphometric techniques. High numbers of cells in the female and male SCN immunoreacted with vimentin in neonates and GFAP in adults. Astrocytes containing vimentin or GFAP were few in number in the SDApc and surrounding areas in neonates and adults, respectively. There was a sex difference in the numerical density of both vimentin and GFAP-positive cells in the SCN. We suggest that (a) pre-astroglia are involved in gender-related organization of the SCN but not in SDApc, and (b) neuroglia have a sex-related, functional role in the mature SCN.

Activation of cultured rat hypothalamic dopaminergic neurons by long-term but not short-term treatment with prolactin.

Pituitary prolactin (PRL) secretion is inhibited by hypothalamic GABAergic and dopaminergic (DAergic) systems. PRL, in turn, appears to be capable of activating these neurons, thus, providing for a negative feedback regulation. We have recently shown that cultured hypothalamic GABAergic- but not DAergic neurons respond to PRL with a rapid increase in intracellular free calcium. Here, we demonstrate that cultured hypothalamic DAergic neurons can be activated in terms of synthesis of dihydroxyphenylalanine (DOPA) by long-term PRL treatment. Short-term PRL treatment was ineffective. It is concluded that hypothalamic DAergic neurons are indeed capable of responding to PRL. However, their response differs from that of GABAergic neurons with respect to time scale and signal transduction. We suggest that the two types of hypothalamic cells are involved in separate feedback loops that provide for tonic and rapid regulation of pituitary PRL secretion, respectively.

Androgens influence sexual differentiation of embryonic mouse hypothalamic aromatase neurons in vitro.

Estrogen formed perinatally in the brain from testicular androgen by aromatase is involved in the irreversible determination of male brain development. Perinatal sex differences in aromatase activity have been observed in the hypothalamus. Testosterone (T) is a major modulator for aromatase in the adult rat hypothalamus. However, it is not known whether circulating T influences aromatase neurons during fetal brain development. To study the influence of androgen exposure on embryonic neuronal aromatase, gender-specific primary cell cultures were prepared from embryonic day 15 mouse hypothalamus and cortex. Estrogen formation by cultured neurons was measured using an in vitro 3H2O product formation assay, and aromatase neurons were identified by immunocytochemistry using a highly specific antiserum. Aromatase activity (AA) per well and numbers of aromatase-immunoreactive (IR) neurons per microtubulus associated protein II-IR neurons x 10(5) were significantly higher in male hypothalamic cultures compared with female when grown in the absence of sex steroids. When AA was calculated per aromatase-IR neuron, no differences in enzyme activity were found between male and female. Therefore, the level of AA in individual male hypothalamic neurons is similar to the female, but a higher proportion of male neurons express aromatase. After T treatment, AA per well (P < or = 0.001) and AA/aromatase-IR cell (P < or = 0.005) in male and female hypothalamic cultures was significantly increased vs. controls. In addition, numbers of aromatase-IR neurons/microtubulus associated protein II-IR neurons x 10(5) were significantly higher after T exposure compared with controls (P < 0.001). Androgenic effects on hypothalamic AA and aromatase-IR cell numbers were dose-dependent and mediated via androgen receptor stimulation, since the observed effects were inhibited by the androgen-receptor antagonist flutamide. There was no effect of T on cortical AA or aromatase-IR cell numbers, indicating area-specific regulation of brain aromatase. We conclude that 1) sex differences in hypothalamic AA are due to a higher percentage of neurons expressing aromatase in males rather than to higher AA in individual male hypothalamic aromatase-IR cells, and 2) androgens influence the development of the fetal hypothalamic aromatase system. Because T influenced both the embryonic male and female hypothalamic neurons in culture, the developing mouse brain aromatase appears to be bipotential in response to androgen. The data suggest that environmental and genetic factors affecting androgen level and/or androgen receptor function in the developing brain could interfere with the sexual differentiation of estrogen forming neurons.

Aromatase-immunoreactivity is localised specifically in neurones in the developing mouse hypothalamus and cortex.

Local formation of oestrogens from androgens by aromatase cytochrome P-450 within brain cells is crucial for the sexual differentiation of the mammalian CNS. Aromatase activity has been detected in several brain regions of the developing rodent brain. In the present study, we used a mouse-specific, peptide-generated, polyclonal aromatase antibody to determine whether neurones and/or glial cells in the developing brain are involved in androgen aromatization and if aromatase-immunoreactive (Arom-IR) cells exhibit a sex-specific distribution and regional-specific morphological characteristics. For these experiments, gender-specific cell cultures were prepared from embryonic day 15 mouse hypothalamus and cortex. Specificity of the immunoreaction was confirmed by Western-blot analysis and by inhibition of aromatase activity using tissue homogenates from mouse ovaries and male newborn hypothalamus and from male hypothalamic cultures with known aromatase activity, respectively. Arom-IR cells were found in both hypothalamic and cortical cultures. Double-labeling experiments revealed that Arom-IR cells co-stained only for the neuronal marker MAP II, but never for glial markers. Therefore aromatase immunoreactivity is specifically neuronal. Regional differences in the morphology of Arom-IR neurones were observed between both brain regions. In hypothalamic cultures, IR-neurones represented a heterologous population of phenotypes (magnocellular, small bipolar and multipolar neurones with long processes showing varicose-like structures or without processes). Cortical Arom-IR neurones were always oval in shape with short or no IR-processes. Sexual dimorphisms in numbers of Arom-IR neurones were found in the hypothalamus with significantly higher cell numbers in male cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Gender-specific brain formation of oestrogen in behavioural development.

Steroid sex hormones have an organisational role in the development of brain mechanisms underlying gender-specific behaviour. Although peaks in gonadal androgen occur at developmental stages that coincide with sensitive periods for the differentiation of both structural sex differences in the brain and sexual behaviour, the factors that control the phasic effects of steroids are still not understood. Aromatase, converting androgen to oestrogen, is a key enzyme in development, and regulation of the activity of this enzyme is likely to be one of the factors determining availability of oestrogen effective for brain differentiation. Measurement of testosterone metabolism in vitro shows that in the mouse oestrogens are formed actively in the neonatal brain during male development. In cultured cells of the embryonic mouse hypothalamus there are sex differences in hypothalamic aromatase activity both during early embryonic and later perinatal development, with a higher capacity for oestrogen formation in the male than in the female. The sex differences are regionally specific, since no differences in aromatase activity are detectable in cultured cortical cells between male and female. Aromatase activity is neuronal rather than astroglial. Using a specific antibody to the mouse aromatase, immunoreactivity is also restricted to neuronal soma and neurites in hypothalamic cultures. Therefore, gender-specific differences in aromatase regulation are probably restricted to neurons. Testosterone increases oestrogen formation specifically in cultured hypothalamic neurones, but has no effect on cortical cells. Although there is a sex difference in early embryonic neuronal aromatase, aromatase activity appears to be sensitive to androgen only in later embryonic development. What determines the phasic sensitivity of the developing brain aromatase system to androgen has still to be determined.

Aromatase-immunoreactive neurons in the adult female chicken brain detected using a specific antibody.

Estrogen formation in the brain catalysed by the cytochrome P450arom is required for the control of estrogen-dependent neural mechanisms regulating reproductive behaviour. A polyclonal antibody was raised against a 15-amino acid fragment of the chicken ovarian P450arom protein, to localise aromatase-immunoreactive (AR-IR) cells in the adult female chicken brain. Specificity of antibody reaction was established by Western blot and by inhibition of aromatase activity in homogenates of chicken ovarian follicles determined by a radiometric assay. The AR-IR material in the brain was localised in the perikarya and some of their adjacent cytoplasmatic processes. Intense immunoreactivity was observed in the preoptic region as well as in other hypothalamic nuclei. AR-IR cells were also found in extrahypothalamic areas; in particular, in the area entorhinalis and hippocampus. These results confirm histologically that aromatization of testosterone in the adult female chicken brain occurs in preoptic nuclei closely associated with the regulation of reproductive behaviour. The mapping of AR-IR cells in the female chicken brain now allows study of its regulation under different physiological and environmental conditions, and its relation to classic target areas expressing estrogen receptors.

Sex-specific aromatization of testosterone in mouse hypothalamic neurons.

Conversion of androgens to oestrogens by neural aromatase during brain development appears to be a prerequisite for sexual differentiation of the mammalian central nervous system. In order to investigate the pre- and perinatal patterns of testosterone (T) aromatization in the male and female mouse brain, aromatase activity (AA) was measured in hypothalamic and cerebral homogenates of embryonic day (ED) 17 fetuses and neonates using an in vitro 3H2O product formation microassay. In addition, AA was examined in gender-specific neuronal cell cultures prepared from ED 15 mouse cerebral hemisphere and hypothalamus at 3 and 6 days in vitro (DIV), and this was compared with enzyme activities in homogenates. The aromatase has also been evaluated in glial-enriched cultures from ED 20 mouse hypothalamus and cortex as well as in ED 15 cultures treated with the neurotoxin kainic acid in order to localize AA to neurons and/or glial cells. Significant sex differences in AA were observed in hypothalamic tissue homogenates as early as ED 17, becoming even more distinct in neonates, AA being always higher in males compared to females. Similar AA was also found in cells from both sexes from cultured ED 15 hypothalamus after 3 DIV. However, significantly higher AA was observed after 6 DIV in ED 15 male hypothalamic cultures compared to female. ED 20 glial-enriched hypothalamic cultures (purity > 95%) from both brain regions exhibited very low AA after 6 DIV, and no sex differences were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Kainic acid has cell-specific effects on survival of hypothalamic mouse neurones in vitro.

Cultures of mouse hypothalamus from embryonic day 15 fetuses were exposed to kainic acid (KA) to study effects on survival of selected cell populations. After 6 days in vitro, immunocytochemistry revealed destruction of dopaminergic and GABAergic neurones after KA-treatment, whereas numbers of oxytocinergic cells and neurones containing metEnkephalin were unchanged. Surviving neurones were characterized by a loss of processes or a reduction of process length. Glial cell numbers did not show any differences between groups. Amino acid concentrations decreased after KA-treatment; only glutamine and taurine levels were unaffected. We conclude that toxic effects of KA differ with respect to distinct neuronal populations of the mouse hypothalamus. Therefore, experimental data concerning neuronal destruction under in vitro conditions have to take into account the selectivity of this neurotoxic agent.

Sex differences of hypothalamic prolactin cells develop independently of the presence of sex steroids.

There is evidence for a hypothalamic prolactin (PRL) system that expresses sexually dimorphic traits. The aim of this in vitro study is to gain an insight into the process of sexual differentiation of hypothalamic PRL cells. In particular, we wanted to determine whether sexual differentiation of these cells can occur independently of the surge of gonadal testosterone which, in the male rat embryo, takes place at embryonic day (E) 18 and is commonly believed to start the critical period of sexual differentiation of the brain. Gender-specific cell cultures were prepared from E 14 or E 17 rat diencephalon and raised in the absence of gonadal steroids. After 10 days in vitro, numbers of PRL-immunoreactive (IR) cells and PRL levels were quantified by immunocytochemistry and Western blotting, respectively. Numbers of PRL-IR cells and PRL levels were 2-3 times higher in cultures prepared from female than from male embryos of either age. It is concluded that sexual differentiation of hypothalamic PRL cells starts well before the generally acknowledged onset of the critical period and may proceed independently of the action of gonadal testosterone. Besides gonadal steroids, other mechanisms, such as cell-intrinsic realization of a sex-specific genetic program, may be responsible for initiating the development of sexually dimorphic neuronal phenotypes.

Neonatal sepsis in an intensive care unit and results of treatment.

Incidence and fatality of neonatal sepsis in intensive care units have been relatively high despite progress in the management of very ill neonates and combined treatment of sepsis with antibiotics. Between 1985 and 1989 944 children (632 premature babies and 312 term babies) were treated in the intensive care unit of the University Children's Hospital of Kiel. The incidence of sepsis was 5% (congenital sepsis 4%, sepsis acquired after birth 1%). Pneumonia occurred in 4% (congenital pneumonia in 2%, postnatal pneumonia in 2%). Early diagnosis and treatment with piperacillin plus cefotaxime reduced the mortality rate of sepsis to 2%. Sepsis never developed under treatment with piperacillin plus cefotaxime. Early recognition of neonatal sepsis by a good blood culture technique and beginning of treatment on first suspicion of sepsis with cefotaxime and piperacillin can improve the results especially in intensive care patients.