Pregnancy lactogens in the rat conceptus and fetus: circulating levels, distribution of binding, and expression of receptor messenger ribonucleic acid

To clarify the roles of the rat placental lactogens in embryogenesis and fetal development, we measured the concentrations of rat placental lactogen-II (rPL-II) in fetal rat serum and examined the distribution and expression of rPL-I- and rPL-II-binding sites in rat uteroplacental and fetal tissues. The concentration of rPL-II in fetal rat serum on day 20 of gestation was 28.3 +/- 0.8 ng/ml (mean +/- SEM; n = 6), approximately 1/14th its concentration in maternal serum (398.3 +/- 45.3 ng/ml; n = 6). In the midgestational uterus and placenta, rat PL-I bound specifically to mesometrial decidua and to a capsular layer of stroma overlying the antimesometrial decidua. The binding of radiolabeled rPL-I to these tissues was inhibited by unlabeled rat PRL and human (h) GH, but not by rat GH, suggesting that the rPL-I-binding sites are lactogenic in nature. In the late gestational fetus, rat PL-II bound specifically to fetal adrenal, kidney, small intestine, liver, and pancreas; its binding, like that of rPL-I, was inhibited by rPRL, but not by rGH. rPL-II-binding sites in fetal adrenal were detected as early as day 16, whereas rPL-II-binding sites in fetal kidney and small intestine were not demonstrable until day 18. Lactogenic binding sites in fetal liver and pancreas did not appear until days 19-20. The relative amounts of specific binding of rPL-II to fetal tissues correlated positively with tissue levels of expression of the 4.2- and 1.8-kilobase PRL receptor mRNA transcripts. Radiolabeled hGH, which interacts with somatogenic receptors as well as lactogenic receptors, bound specifically to mesometrial decidua, fetal adrenal, kidney, small intestine, liver, and pancreas. In addition, radiolabeled hGH bound specifically, but with low intensity, to fetal brain. In mesometrial decidua and fetal adrenal, kidney, and small intestine, the binding of hGH was blocked by rPL-II and rPRL, but not by rGH or ovine GH, suggesting the predominance of lactogenic receptors. In contrast, in fetal brain, the binding of hGH was inhibited by rGH, but not by rPL-II, suggesting that the fetal brain contains somatogenic receptors. The presence of rPL-I-binding sites in maternal decidua suggests a paracrine role for the hormone in decidual function at midgestation. The presence of rPL-II in fetal serum and the widespread distribution of rPL-II-binding sites in fetal tissues indicate a role for rPL-II in fetal development.

Augmenting and reducing of visual evoked potentials in Roman high- and low-avoidance rats

Human and cat high sensation seekers tend to show increasing amplitudes (augmenting) of the P1 and N1 components of the visual evoked potential (VEP) to increasing intensities of light flash, whereas low sensation seekers show VEP reducing. Roman high-avoidance (RHA) and Roman low-avoidance (RLA) rats have behavioral traits comparable to human and cat high and low sensation seekers, respectively. RHA rats show greater exploration, activity, and aggression than do RLA rats. Rats of each Roman line and Wistar rats were anesthetized with chloral hydrate and maintained at a stable moderate anesthetic level. VEPs to each of five flash intensities were computer averaged for each rat. The slopes of P1 amplitudes as a function of flash intensity were significantly greater in the RHA than the RLA rats. RHA rats were clear augmenters; RLA rats had almost flat amplitude-intensity functions. The Wistar rats had slope functions that were similar to those of the RLA rats. This study shows that the relationship between sensation-seeking behavior and VEP augmenting and reducing has a heritable base and extends across species from human, cat, and rat. In addition, we demonstrate a rat model of this relationship that yields advantages of genetic homogeneity and a short generational time, and provides access to a wealth of behavioral data and experimental manipulations available for the rat.

An important complication of upper cervical spine fracture: a case report

A case report is presented of a patient who sustained a high cervical spine fracture, the possible mechanisms of injury and details of the fracture are discussed. The patient developed bilateral vagal nerve palsies 48 h after the accident. This complication was only recognized after dysphagia and an aspiration pneumonia developed. The complication of aspiration pneumonia was preventable. Meticulous and repeated examination of the cranial nerve function in this type of injury is recommended. Normal feeding should commence only when the cranial nerve function has been shown to be normal after repeated examination.

Weight gain in women with gestational diabetes

OBJECTIVE

To evaluate weight gain during pregnancy in women with gestational diabetes, and to determine whether there was a stronger or weaker correlation of maternal weight gain with neonatal birth weight in women with gestational diabetes as compared with a control group.

METHODS

At delivery, 78 women with gestational diabetes and 312 control subjects were evaluated and classified according to pregravid weight for height (underweight, average weight, and overweight). Weight gain during pregnancy and neonatal birth weight in the women with gestational diabetes and in the control group were compared using analysis of covariance, controlling for selected covariables. A weight gain curve for each patient was generated to assess the rate of weight gain during early, middle, and late gestation. Linear regression analysis was used to correlate maternal weight gain and birth weight.

RESULTS

Weight gain was 2.5 kg less in the women with gestational diabetes as compared with the controls (P = .0006). When adjusted for pregravid weight, maternal age, and gestational age at delivery, only underweight women with gestational diabetes persisted in having significantly less weight gain as compared with the control subjects (P = .035). There were no significant differences in infant birth weight between any gestational diabetes and control weight categories. The rate of weight gain was decreased in over-weight women with gestational diabetes versus control subjects in late pregnancy (P = .05). There was a significant correlation between maternal weight gain and birth weight in underweight (r = 0.46, P = .0001) and average-weight (r = 0.17, P = .02) control women but not in overweight controls or in any patients with gestational diabetes.

CONCLUSION

Weight gain in women with gestational diabetes is less than in control patients, primarily because of greater pregravid weight, and does not correlate with neonatal birth weight.

Postnatal handling, perinatal flumazenil, and adult behavior of the Roman rat lines

The effect of infantile handling stimulation and/or perinatal flumazenil (Ro 15-1788; a benzodiazepine receptor antagonist; 3.7 mg/kg/day) administration on exploratory and emotional-related behavior was investigated using adult females from the Roman high- and low-avoidance (RHA/Verh and RLA/Verh) lines. When rats (6 months old) were exposed to a hexagonal tunnel maze including an illuminated central arena, it was found that RHA/Verh rats were more active, explored more maze area, showed more outward preference, and more frequently entered the illuminated center than RLA/Verh rats. In addition, postnatal stimulation decreased emotional-related behavior in both lines of rats, as expressed by increased entry into, and time spent in, the central arena. Perinatal flumazenil treatment decreased entry into the maze central arena in both rat lines but this effect was counteracted by postnatal (handling) stimulation. Thus, the present study extends to adult RHA/Verh and RLA/Verh rats the positive long-lasting effects of postnatal handling and shows postnatal handling x flumazenil interactions in some behavioral parameters related to the pattern of exploration and exploratory efficiency.

Precise prediction of a Kk-restricted cytotoxic T cell epitope in the NS1 protein of influenza virus using an MHC allele-specific motif

The nonstructural protein NS1 of influenza A/PR/8/34 virus has previously been reported to be recognized by murine Kk-restricted cytotoxic T lymphocytes (CTL), although the sequence of the epitope was not defined. A Kk-specific motif has previously been published and consists of a glutamic acid or (less frequently) an aspartic acid at position 2 and an isoleucine at the carboxyl terminus of a peptide eight or nine residues long. This motif was used here to predict the sequence of the NS1 epitope, which was defined as a nonapeptide corresponding to amino acid residues 152-160, sequence EEGAIVGEI. This is the first CTL epitope to be defined within the NS1 protein of the influenza A virus. A model of how this epitope could bind to the Kk molecule was produced by homology modelling from an X-ray crystal structure of a human HLA/peptide complex.

A sequence pattern for peptides presented to cytotoxic T lymphocytes by HLA B8 revealed by analysis of epitopes and eluted peptides

HLA B8-restricted cytotoxic T lymphocytes (CTL) specific for influenza A virus were generated and shown to recognize the nucleoprotein (NP). The dominant epitope was mapped using recombinant vaccinia viruses that expressed fragments of the NP and then synthetic peptides based on the NP amino acid sequence. The peptide 380-393 was first identified and further refined; it was shown that the glutamic acid at position 380 was essential for recognition by CTL and that the nonamer 380-388 was the optimum peptide. Six HLA B8-positive influenza immune donors that we have tested respond to this peptide as part of their influenza-specific CTL response. The amino acid sequence of the peptide epitope was compared to six other known virus peptides known to be restricted by HLA B8 and a sequence homology was identified, which predicted nonamer and octamer epitope sequences. Probable anchor residues were identified at peptide residues 3 (lysine/arginine), 5 (lysine/arginine) and 9 (leucine/isoleucine). Support for this pattern came from sequencing peptides eluted from purified HLA B8 molecules, where lysines were predominant at positions 3 and 5. One of the predicted epitope peptides was made and shown to be recognized by specific CTL. These and the two others were shown to compete with NP 380-388 for binding to HLA B8. A model was made of the HLA B8 molecule and negatively charged pockets predicted, which could accommodate the positively charged side chains of the peptide anchor residues.

Vasopressinergic modulation of stress responses in the central amygdala of the Roman high-avoidance and low-avoidance rat

The central nucleus of the amygdala (CEA) is selectively involved in the passive component of the behavioral (immobility) and the accompanying parasympathetic response during conditioned, stressful environmental challenges. Vasopressinergic mechanisms in the brain seem to play a role in these stress responses. The effects of the neuropeptides arginine-8-vasopressin (AVP) and oxytocin (OXT) on modulating CEA activity during conditioned stress of inescapable footshock were studied in male Roman high-avoidance (RHA/Verh) and low-avoidance (RLA/Verh) rats, psychogenetically selected on the basis of shuttle-box acquisition behavior. In RLA/Verh rats, the cardiac and behavioral responses to the conditioned emotional stressor were bradycardia and immobility, suggesting an important role for the CEA in these rats. The RHA/Verh rats, however, failed to show any change in heart rate or immobility in response to a conditioned stress situation. The low dose of AVP (20 pg) in the CEA of conscious RLA/Verh rats caused an enhancement of the stress-induced bradycardiac and immobility response. However, the high dose of AVP (2 ng) and OXT (200 pg) attenuated the bradycardiac and immobility responses in the RLA/Verh rats. Infusion of AVP and OXT in the RHA/Verh rats failed to induce any change in heart rate or immobility. Binding studies revealed that the AVP receptor selectively binds AVP with high affinity. In contrast, the OXT receptor recognizes both AVP and OXT with a similar (but lower) affinity. This suggests that the behavioral and autonomic responses of the high dose of AVP may be caused by OXT receptor stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

The management of quinine-induced blindness

Given the potential toxicity of even a small number of quinine tablets we suggest that patients to whom these are prescribed should be alerted to this risk both by the prescribing clinician and by a warning, clearly printed on the tablet container. There is no evidence that increased retinal arteriolar dilation is of any value in the management of patients with quinine induced blindness. Therefore the use of SGB for this condition must be questioned unless a controlled trial is performed which shows benefits. We recommend that the aim of treatment has to be reduction in the plasma level of quinine. The most efficient way of accomplishing this is by repeated oral activated charcoal.

Early stimulation effects on novelty-induced behavior in two psychogenetically-selected rat lines with divergent emotionality profiles

The present study shows that postnatal handling (H: consisting of removing the pups from the nest twice daily and placing them individually in plastic cages lined with paper towel for a period of 10 min, between postnatal days 1 and 21) and/or environmental enrichment (E: for a period of 6 months) of Roman high- and low-avoidance (RHA/Verh and RLA/Verh) rats induced long-lasting decreases in emotional reactivity (i.e. reduced defecations in the open field, OF, and hole-board, HB, tests) as well as increases in exploratory behavior (i.e. head-dipping) in a manner dependent upon the rat line (there were 'line x H' and 'line x E' interactions). It is reported for the first time that RHA/Verh rats show more head-dipping behavior than RLA/Verh rats, and that the environmental treatments can increase head-dipping of RLA/Verh animals to the level shown by RHA/Verh rats.

Diagnostic peritoneal lavage: it's red but is it positive?

The aim of this study was to ascertain whether qualitative assessment could accurately determine a concentration of 100,000 RBC/mm3 in simulated peritoneal lavage fluid. The results show that the qualitative methods used are inaccurate and do not reliably predict a red cell concentration of 100,000 per mm3. We therefore recommend that the red cell concentration of peritoneal lavage fluid is always measured before the result is considered 'positive'.

Differential effects of early stimulation and/or perinatal flumazenil treatment in young Roman low- and high-avoidance rats

The effect of infantile handling-stimulation and/or perinatal flumazenil (3.7 mg/kg/day) administration on exploratory and emotional-related behavior was investigated using Roman high- and low-avoidance (RHA/Verh and RLA/Verh) rats. Postnatal handling increased exploration in 30-day-old rats of both psychogenetically selected lines when they were exposed to a hexagonal tunnel maze including an illuminated central arena. Likewise, postnatal stimulation decreased emotional reactivity in both lines of rats, as expressed by increased entry into the central arena, decreased defecation and vocalization frequency, but these effects were more pronounced in the RLA/Verh line. There were interactions between perinatal flumazenil treatment and rat line, indicating that flumazenil enhanced entry into the maze central arena in handled-RLA/Verh rats, whereas a tendency toward the opposite effect was observed in drug-treated and handled-RHA/Verh animals. Thus, the present study emphasizes that the effects of environmental manipulations are partly dependent upon genetic factors, and that pharmacological effects also depend on both genetic and environmentally-induced predisposition.

Stress and putative endogenous ligands for benzodiazepine receptors: the importance of characteristics of the aversive situation and of differential emotionality in experimental animals

The relationships between anxiety/stress, possible endogenous ligands for benzodiazepine receptors and the behavioral modification by drugs are discussed in this short review, including the specific characteristics of elements involved in those interactions, e.g. ones concerning the aversiveness of the stressful situation and the nature of the organism under investigation. These are important factors when considering aversive tasks, insofar as they may involve stressful conditions which differ in intensity and in the degree of control afforded the subject. These characteristics may well lead to differing functional effects on GABA-gated chloride channels or, in other words, to an incongruous balance between endogenous benzodiazepine receptor agonist and inverse agonist activity. This is not surprising, as it is well known that different forms of stressors often actually produce divergent behavioral, physiological and biochemical effects. This review also illustrates the necessity of taking into account the variable effects of stressors and/or drugs on animals differing in reactivity or emotionality, even in the case of 'non-selected' stocks. The implication is made that, by genetic and/or environmental manipulation of the emotional state of the animals used, it will be possible to obtain more clearly definable results in neuropharmacological and psychopharmacological studies.

Infantile (handling) stimulation and behavior in young Roman high- and low-avoidance rats

The effect of infantile handling stimulation on exploratory and emotional behavior of Roman high- and low-avoidance (RHA/Verh and RLA/Verh) weanling rats was investigated. Postnatally handled and nonhandled, 4-week-old males and females from both psychogenetically selected lines were exposed to a hexagonal tunnel maze, including an illuminated central arena. Postnatal handling increased exploratory behavior and decreased emotional reactivity as expressed by increased entries into the central arena and a reduction in defecations in both lines of rats. These effects were more pronounced in the RLA/Verh rats. In agreement with earlier studies using nonselected adult rats, the females of both lines (especially those from the RHA/Verh line) were more sensitive than males to the positive influences of early stimulation.

ABC of major trauma. Trauma in pregnancy

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ABC of major trauma. Transport of injured patients

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