Successful treatment with ampicillin and fluoroquinolones of human endocarditis due to high-level gentamicin-resistant enterococci

Two cases of endocarditis, one caused by high-level gentamicin-resistant Enterococcus durans and the other by high-level gentamicin- and glycopeptide-resistant Enterococcus faecalis. successfully treated with a combination of ampicillin and a fluoroquinolone are reported. Both strains were susceptible to ampicillin. Enterococcus faecalis was susceptible to ciprofloxacin and to ofloxacin, but Enterococcus durans was moderately resistant to these agents. Microbiological and clinical cure was obtained with a 6-week course of ampicillin plus ciprofloxacin in one case and with ofloxacin in the second case due to intolerance to ciprofloxacin. The efficacy of the treatment was predicted in vitro by time-kill studies and by adequate serum bactericidal titres.

Potential coanthracyclinic activity of pyridylmethylene-2-indolinones

The paper reports the cytotoxic activity of pyridylmethylene-2-indolinones previously described as cardiotonics and the synthesis of three analogs of the most potent cytotoxic agent. Some of these compounds could be useful, when associated with anthracyclines, to reduce the cardiotoxicity of these potent antitumor drugs.

Disposition of Cremophor EL in humans limits the potential for modulation of the multidrug resistance phenotype in vivo

The purpose of the present study was to characterize the distribution and elimination kinetics of the paclitaxel vehicle Cremophor EL (CrEL), a polyoxyethylated castor oil that can modulate P-glycoprotein-mediated multidrug resistance in vitro. The pharmacokinetics of CrEL were studied using noncompartmental models in 23 patients with histological proof of malignant solid tumors, receiving paclitaxel as a 3-h i.v. infusion at dose levels ranging from 100-225 mg/m2 (corresponding to CrEL doses of 8.33-18.8 ml/m2). Serial plasma samples were obtained before and up to 72 h after drug administration, and were analyzed for the presence of CrEL by a novel colorimetric dye-binding microassay. The area under the plasma concentration versus time curves and the peak plasma levels of CrEL increased from 253+/-36.8 (mean+/-SD) to 680+/- 180 microl.h/ml, and from 3.40+/-0.10 to 6.58+/-0.52 microl/ml, respectively, consistent with linear pharmacokinetics. Disappearance of CrEL from the central plasma compartment was characterized by a terminal elimination half-life of 84.1+/-20.4 h, resulting in extended persistence of substantial levels even at 1 week after paclitaxel treatment. The observed volume of distribution was extremely low and averaged 3.70+/-0.49 liters/m2, implying that the tumor delivery of CrEL is insignificant. Our results indicate that CrEL is a relatively slow clearance compound and that its distribution is limited to the central plasma compartment. Hence, CrEL is not likely to play a role in reversing P-glycoprotein-mediated multidrug resistance to paclitaxel in vivo.

In vivo cardiotonic activity of pyridylmethylene-2-indolinones

The synthesis of 5-chloro-3-pyridylmethylene-2-indolinone is reported. This compound was subjected to an in vivo cardiotonic assay with 10 analogs whose synthesis and in vitro cardiotonic activity were previously reported. All the compounds tested (except the 5-hydroxyindole derivative) showed significant positive inotropic activity. The 3-pyridyl derivative without substituents at the indole system was the most active of the whole series.

Aortic arch surgery: retrospective analysis of outcome and neuroprotective strategies

BACKGROUND

OBJECTIVE

To review intra- and postoperative data regarding surgical reconstruction of the aortic arch performed at our cardiosurgical centre during the past four years, and thus to deepen understanding of neurologic morbidity and of what constitutes the most effective neuroprotection.

EXPERIMENTAL DESIGN

Retrospective study.

SETTING

Regional University Hospital.

PATIENTS

29 patients who underwent reconstruction of aneurysm or dissection of the aortic arch. Intervention. Surgical replacement of the diseased aorta during deep hypothermia, alone or with selective cerebral perfusion (antegrade or retrograde).

MEASURES

Overall mortality rate, neurologic morbidity rate, duration of extracorporeal circulation, of hypothermic circulatory arrest or of selective cerebral perfusion. Evaluation of the importance to neurological outcome of age, modality of operation (emergency or routine), biochemical parameters (glycemia, hematocrit) and perfusion technique. Recording of postoperative time of arousal, and possible correlation with length of selective cerebral perfusion.

RESULTS

We observed a mortality rate of 39% (11 deaths) and a neurologic morbidity rate of 34%. Hypothermic circulatory arrest alone did not assure valid neuroprotection (5 cases, all with severe neurologic impairment), while better results were obtained with selective cerebral perfusion, especially antegrade (14 cases, with only 7% of neurologic morbidity rate). Hyperglycemia (>250 mg%) proved to be significantly associated (p=0.002) with increased incidence of adverse neurologic outcome, and the same association was observed between emergency status and adverse neurologic outcome (p=0.002). Moreover, we found an unexpected linear correlation between time of selective cerebral perfusion and postoperative time of arousal (r=0.728, p=0.000).

CONCLUSIONS

Deep hypothermic circulatory arrest with selective cerebral perfusion currently represent a valid therapeutic option for brain preservation during reconstruction of the aortic arch in adults. It is mandatory to carry out a tight control of perfusion parameters (flow, pressures and temperature gradients) and biochemical variables (avoidance of hyperglycemia and modified ultrafiltration for fluid balance).

Intrauterine infusion of high doses of pig trophoblast interferons has no antiluteolytic effect in cyclic gilts

In the pig species, the preimplanting trophoblast is known to synthesize and secrete high amounts of interferon during early development. Previous experiments in cyclic gilts using total conceptus secretory proteins suggested that porcine trophoblastic interferons, unlike those of ruminants, exert no effect on the luteal cycle. In the present experiment, cyclic Meishan gilts were divided into two groups, cannulated on both uterine horns, and given daily injections of either a placebo or increasing doses of a mixture of recombinant interferon-gamma and interferon-delta, on Days 11-14 of the estrous cycle. In treated gilts, the injected doses were much higher than those previously found in uterine perfusates from pregnant gilts. However, no significant differences could be found between the control (n = 4) and the treated (n = 5) group concerning the days of the estrous cycle for mid-decrease of progesterone (control: Day 14.5+/-0.57 [mean+/-SD]; treated: Day 15+/-1.25), the day of estrus (control: Day 19+/-0.96; treated: Day 19.6+/-0.55), and the subsequent ovulation rate (control: 14+/-2.2 corpora lutea; treated: 13.1+/-1.1 corpora lutea). These data confirm that pig trophoblastic interferons, unlike those of ruminants, do not themselves exert an antiluteolytic effect. A possible synergistic effect of embryonic estrogens on the luteal functions of nonpregnant sows remains to be determined.

Evidence that the mediobasal hypothalamus is the primary site of action of estradiol in inducing the preovulatory gonadotropin releasing hormone surge in the ewe

Although a neural site of action for estradiol in inducing a LH surge via a surge of GnRH is now well established in sheep, the precise target(s) for estrogen within the brain is unknown. To address this issue, two experiments were conducted during the breeding season using an artificial model of the follicular phase. In the first experiment, bilateral 17beta-estradiol microimplants were positioned in either the medial preoptic area (MPOA) or the mediobasal hypothalamus (MBH), and LH secretion was monitored. An initial negative feedback inhibition of LH secretion was observed in ewes that had estradiol microimplants located in the MPOA (6 of 6 ewes) or caudal MBH in the vicinity of the arcuate nucleus (4 of 4). In contrast, a normal LH surge was only found in animals bearing estradiol microimplants in the MBH (5 of 10). Detailed analysis of estradiol microimplant location with respect to the estrogen receptor-alpha-immunoreactive cells of the hypothalamus revealed that 4 of the 5 ewes exhibiting a LH surge had microimplants located bilaterally within or adjacent to the area of estrogen receptor-expressing cells of the ventromedial nucleus. Two of these ewes exhibited a LH surge without showing any form of estrogen negative feedback. In the second experiment, we used the technique of hypophyseal portal blood collection to monitor GnRH secretion directly at the time of the LH surge induced by estradiol delivered either centrally or peripherally. Central estradiol implants induced the GnRH surge. The duration and mean plasma concentration of GnRH during the surge were not different between animals given peripheral or central MBH estradiol implants. Cholesterol-filled MBH microimplants did not evoke a GnRH surge. We conclude that the ventromedial nucleus is the primary site of action for estradiol in stimulating the preovulatory GnRH surge of the ewe, whereas the MPOA and possibly the caudal MBH are sites at which estrogen can act to inhibit LH secretion. These data provide evidence for the sites within the ovine hypothalamus responsible for mediating the bimodal influence of estradiol on GnRH secretion and suggest that different, and possibly independent, neuronal cell populations are responsible for the negative and positive feedback actions of estradiol.

Clinical outcome of mild fetal ventriculomegaly

OBJECTIVE

Our purpose was to evaluate the outcome of fetuses with mild cerebral ventriculomegaly.

STUDY DESIGN

We prospectively collected all cases of mild cerebral ventriculomegaly (transverse diameter of the atrium of the cerebral lateral ventricles between 10 and 15 mm) diagnosed antenatally between January 1990 and December 1996. Associated ultrasonographic abnormalities including markers of aneuploidy, presence of chromosomal anomalies, structural malformations detected at birth, and neurologic outcome were recorded. Outcome information was available on all cases. In addition, published series of cases of fetal mild cerebral ventriculomegaly were reviewed to identify prognostic indicators.

RESULTS

Eighty-two cases fulfilled the inclusion criteria: 48 were isolated and 34 were associated with other ultrasonographic markers or anomalies. Among the 45 surviving euploid isolated cases, neurologic follow-up was normal at a mean age of 28 months (range 3 to 72 months). Male fetuses and those with a transverse atrial size <12 mm had a good prognosis. Ventricular atria > or =12 mm were more often associated with other anomalies (56% vs 6%) and, when isolated, with abnormal postnatal neurodevelopment (23% vs 3%). Aneuploidy was present in two cases of isolated mild cerebral ventriculomegaly, both of which were associated with advanced maternal age, and in seven cases associated with other anomalies.

CONCLUSIONS

Mild cerebral ventriculomegaly should prompt targeted ultrasonographic examination, inclusive of markers of aneuploidies, visualization of the corpus callosum, and echocardiogram as well as serologic evaluation for congenital infections. In isolated mild cerebral ventriculomegaly genetic counseling should take into account clinical, laboratory, and ultrasonographic findings. A review of the published series suggests that cognitive or motor delay is predominantly mild and that it occurs in about 9% of cases of isolated mild cerebral ventriculomegaly.

Chronology of events accompanying follicular atresia in hypophysectomized ewes. Changes in levels of steroidogenic enzymes, connexin 43, insulin-like growth factor II/mannose 6 phosphate receptor, extracellular matrix components, and matrix metalloproteinases

The chronology of changes in levels of some proteins known to be altered during atresia of ovarian follicles was studied in ewes hypophysectomized at the end of the follicular phase of the estrous cycle. This study was performed by quantitative immunohistochemistry and zymography on large antral follicles (diameter > 3.5 mm) normally destined to ovulate, recovered 24, 36, or 72 h after pituitary ablation. The process of atresia was followed by comparing healthy follicles from intact ewes, with early atretic follicles recovered 24 h after hypophysectomy, clearly atretic follicles recovered 36 h after hypophysectomy, and late atretic follicles recovered 72 h after hypophysectomy. The earliest events of atresia induced by hypophysectomy were detected in theca and consisted of a strong decrease in levels of fibronectin (p < 0.001) and insulin-like growth factor II/mannose 6 phosphate (IGF-II/M6P) receptors (p < 0.05), occurring within the first 24 h following pituitary ablation. In intact animals, similar changes were observed in theca of early atretic follicles, suggesting that these changes may be important events involved in the onset of follicular atresia. In parallel, intrafollicular levels of matrix metalloproteinase-2 and -9 were shown to increase as early as 24 h after hypophysectomy, and a further increase was observed until 72 h after hypophysectomy. These early events were followed by the disappearance of P450 aromatase in granulosa cells 36 h after hypophysectomy (p < 0.05), and a progressive decrease in levels of P450 17alpha-hydroxylase in the theca interna and of gap junction protein connexin-43 in granulosa cells; these markers were still detectable in late atretic follicles 72 h after hypophysectomy. The increase in levels of fibronectin, type IV collagen, laminin, and IGF-II/M6P receptors within granulosa cell layers (p < 0.05) was significant only in late atretic stages, suggesting that these changes may be consequences rather than causes of atresia.

Effect of long-term cocaine administration to pregnant ewes on fetal hemodynamics, oxygenation, and growth

OBJECTIVE

To assess uterine and fetal blood flows by Doppler velocimetry and fetal growth and oxygenation in pregnant ewes treated daily with cocaine and to determine whether cocaine impairs fetal cardiac and cerebral reactivity.

METHODS

The study groups received 70 mg (n = 7) or 140 mg (n = 7) of cocaine and the control group (n = 7) received placebo injected intramuscularly daily on days 60-134. Hemodynamic data were measured at rest and during two acute hypoxic tests at cesarean delivery performed on day 134.

RESULTS

The fetal heart rate (FHR) and umbilical and uterine resistance indices (RIs) were higher in the cocaine groups than in the control group (FHR: 187 +/- 8 and 166 +/- 8 beats per minute at 83 and 123 days, respectively, in controls and 9-11% higher in cocaine groups; umbilical RI: 0.79 +/- 0.06, 0.60 +/- 0.04, and 0.52 +/- 0.06, at 83, 105, and 123 days, respectively, in controls and 11-17% higher in the cocaine groups [P < .01]; and uterine RI: 0.40 +/- 0.05, 0.40 +/- 0.04, and 0.37 +/- 0.04, at 83, 105, and 123 days, respectively, in controls and 13-35% higher in cocaine groups [P < .05]). At delivery on day 134, the following characteristics were found to be different in the cocaine groups: fetal weight (4.03 +/- 0.2 kg in controls and 15-21% lower in the cocaine groups [P < .02]), partial pressure of oxygen (26.5 +/- 1.4 mmHg in controls and 15-16% lower in cocaine groups [P < .05]), umbilical RI (0.40 +/- 0.03 in controls and 11-17% higher in cocaine groups [P < .01]), cerebral RI (0.61 +/- 0.03 in controls and 9-15% lower in cocaine groups [P < .01]), and cerebral-umbilical ratio (1.52 +/- 0.04 in controls and 22-23% lower in cocaine groups [P < .001]). During the hypoxic tests, the cerebral RI (P < .05) and the cerebral-umbilical ratio (P < .05) decreased significantly less in the two cocaine groups. The FHR response was reduced significantly in the two cocaine groups (P < .05).

CONCLUSION

Long-term exposure to cocaine induces uterine and fetal blood flow disorders, fetal growth restriction, and hypoxia. It reduces the capability of the cerebral vessels to vasodilate and the heart rate to increase during acute hypoxia.

Amnioinfusion for prevention of pulmonary hypoplasia in second-trimester rupture of membranes

We conducted a study to evaluate the feasibility and benefits of transabdominal amnioinfusion in preterm premature rupture of membranes with persistent oligohydramnios for the prevention of pulmonary hypoplasia. To this purpose, we designed a cohort study in which the pregnancy outcome of women with rupture of membranes at < or = 25 weeks and persistent (> or = 4 days) oligohydramnios managed with serial amnioinfusions (n = 18) was compared with that of a historic cohort group (controls) with similar characteristics but managed expectantly (n = 16). Pulmonary hypoplasia was diagnosed at birth in the presence of strict radiological and pathological criteria. No amnioinfusion-related complications occurred. The prevalence of pulmonary hypoplasia was significantly lower among the amnioinfused cases compared with the controls (46% [6 of 13] vs 86% [12 of 14], odds ratio [OR] = 0.4, 95% confidence interval [CI] 0.2-0.9), despite a lower gestational age at rupture of membranes in the treated group. Within the group undergoing amnioinfusions, those in which the infused solution was rapidly lost had a higher rate of pulmonary hypoplasia compared with those in which amnioinfusion alleviated oligohydramnios for > 48 hours (considered successful) (0 of 4 vs. 6 of 9, OR = 2.3, 95% CI 1-5.5). Cases of successful amnioinfusion had a longer interval between membrane rupture and appearance of oligohydramnios than those in which the procedure failed to correct oligohydramnios, even though both groups had similar gestational age at appearance of oligohydramnios. This suggests that the rate of loss of amniotic fluid after membrane rupture may predict the rate of loss of the infused solution, and therefore identify a subset of patients who may benefit from the procedure.

Human pharmacokinetic characterization and in vitro study of the interaction between doxorubicin and paclitaxel in patients with breast cancer

PURPOSE

We performed a pharmacologic investigation of paclitaxel (PTX) infused over 3 hours and bolus doxorubicin (DOX) to assess the role of sequence, interval between drugs, and duration of doxorubicin infusion on paclitaxel and anthracycline plasma disposition. We also explored possible mechanisms of pharmacokinetic interference involving the physiologic role of the multidrug resistance phenotype in anthracycline and taxane biliary excretion.

PATIENTS AND METHODS

Pharmacokinetics was performed in 80 cycles and 36 women with previously untreated metastatic breast cancer. PTX, DOX, and their metabolites 6 alpha-hydroxyl-PTX (6 alpha OH-PTX) and doxorubicinol (DOL) were measured by high-pressure liquid chromatography (HPLC). Human breast cancer MCF-7 wild-type (WT) and resistant (TH) cell lines were cultured in whole human plasma to study anthracycline retention after treatment with different combinations of PTX, Cremophor EL (CEL) (PEG35 castor oil; BASF, Parsippany, NJ), and DOX.

RESULTS

Pharmacokinetic interference between PTX and DOX was responsible for nonlinearity of DOX plasma disposition and increased concentrations of DOX and DOL. These effects were PTX dose-dependent, DOX concentration-dependent, and likely a result of interference at the level of liver elimination. In view of the physiologic role of P-glycoproteins (P-gp) in xenobiotic biliary excretion, retention of DOX was assessed in MCF-7 WT and MCF-7 TH cells. Intracellular was significantly higher in MCF-7 WT than MCF-7 TH (P < .05). However, concomitant exposure to DOX, PTX, and CEL caused similar DOX retention in both MCF-7 WT and TH cells.

CONCLUSION

PTX, as clinically formulated in CEL, is responsible for a nonlinear disposition of DOX and DOL. Nonlinearity is PTX- and DOX-dependent, and possibly caused by competition for biliary excretion of taxanes and anthracyclines mediated by P-gp. Nonlinearity indicates that even minor modifications of dose and infusion duration of DOX and PTX may lead to unpredictable pharmacodynamic consequences. The postulated role of P-gp suggests that CEL is clinically active, and advises caution in designing combinations of PTX with other drugs that are substrate for P-gp.

Expression of messenger ribonucleic acids of insulin-like growth factor binding protein-2, -4, and -5 in the ovine ovary: localization and changes during growth and atresia of antral follicles

In the sheep as in many mammalian species, growth and atresia of antral follicles are characterized, respectively, by a decrease and a high increase in the intrafollicular levels of insulin-like growth factor binding proteins of less than 40 kDa (IGFBPs < 40 kDa), mainly IGFBP-2, -4, and -5. The objective of this study was to investigate whether such changes are associated with changes in follicular expression of the corresponding mRNA. For this purpose, ovaries were recovered from ewes slaughtered at the end of follicular phase (i.e., 30 h after progestagen sponge removal; control ewes) or at 24 h, 36 h or 72 h after hypophysectomy (hypox) performed 30 h after sponge removal. The expression of mRNA of IGFBPs of less than 40 kDa (IGFBPs < 40 kDa mRNA) was studied in ovine antral follicles from control and hypox ewes by in situ hybridization using [35S]-labeled human IGFBP-2, -4, and -5 cRNA as probes. In control ewes, IGFBP-2 mRNA was mainly expressed in granulosa as a gradient in healthy follicles, the expression being higher in granulosa cells close to the basal membrane than in granulosa cells bordering the antrum and within the cumulus. The level of IGFBP-2 mRNA was lower both in granulosa cells close to the basal membrane and in those bordering the antrum from small follicles than in the corresponding compartments of granulosa cells from large healthy follicles (p < 0.05). In healthy follicles, IGFBP-4 and -5 mRNA were mainly expressed in thecal cells. No change in level of IGFBP-4 mRNA was observed between small and large follicles, whereas the level of IGFBP-5 mRNA tended to be lower in thecal cells from large compared to small follicles (p = 0.055). In atretic follicles, expression of IGFBPs < 40 kDa mRNA strongly increased in granulosa (IGFBP-2 and -5, p < 0.01) and in thecal cells (IGFBP-2 and -4, p < 0.01). In hypox ewes, the chronology of changes in expression of follicular IGFBPs < 40 kDa mRNA and in intrafollicular levels of the corresponding proteins was studied during atresia of large antral follicles. Early atresia of large follicles was associated with a strong decrease in intrafollicular estradiol levels (p < 0.001); an increase in intrafollicular levels of IGFBP-2, -4, and -5 (p < 0.001) an increase in both IGFBP-2 (p < 0.001) and -5 (p < 0.01) mRNA expression in granulosa and thecal cells; but no changed in IGFBP-4 mRNA expression. Late atresia of large follicles was associated with a further decrease in intrafollicular estradiol levels (p < 0.01); a further increase in intrafollicular levels of IGFBP-2, -4, and -5 (p < 0.001); an increase in IGFBP-4 (p < 0.01) and -5 (p < 0.05) mRNA expression in theca and granulosa, respectively; a decrease in IGFBP-5 mRNA expression in theca (p < 0.05); but no further increase in IGFBP-2 mRNA expression. Overall, these data suggest that the decrease and the increase in expression of mRNA of follicular IGFBPs < 40 kDa during follicular growth and atresia, respectively, are involved in the decrease and the increase in intrafollicular levels of the corresponding proteins. Moreover, the increases in expression of follicular IGFBPs < 40 kDa during atresia of large follicles in hypophysectomized ewes followed a specific time course, the increase in IGFBP-2 and -5 mRNA expression being early than the increase in IGFBP-4 mRNA expression.

Potential antitumor agents. 25 [1]. Synthesis and cytotoxic activity of 3-(2-chloro-3-indolylmethylene)1,3-dihydroindol-2-ones

The Knoevenagel reaction between 2-indolinones and 2-chloroindolaldehydes gave 3-(2-chloro-3-indolylmethylene)1,3-dihydroindol-2-ones which were tested as potential antitumor agents on cultures of HeLa cells. 2-Chloro derivatives with at least one unsubstituted NH group, are promising candidates for further investigation.

Different susceptibility of coagulase-positive and coagulase-negative staphylococci to ciprofloxacin

Ciprofloxacin susceptibility was evaluated in 573 clinical staphylococcal isolates (Staphylococcus aureus 230, methicillin-resistant (MR) 36%; coagulase-negative strains 343, MR 66%) collected from 1989 to 1995. Resistance to ciprofloxacin for MR Staphylococcus aureus was 25% until 1991 when ciprofloxacin was introduced into the hospital formulary, and rose progressively to 90% in 1994-1995. MR Staphylococcus haemolyticus showed a ciprofloxacin resistance of 46% until 1991 and of 73% from 1992 to 1995. In contrast MR Staphylococcus epidermidis and other coagulase-negative strains showed a constant susceptibility to this agent (80%). Ciprofloxacin has limited usefulness against MR Staphylococcus aureus but can be still used to treat Staphylococcus epidermidis infections.

Clinical significance of fetal intracranial hemorrhage

OBJECTIVE

We reviewed our experience with six consecutive cases of fetal intracranial hemorrhage and the cases published in the English literature in an attempt to devise an original prognostic scoring system for antenatal intracranial hemorrhage.

STUDY DESIGN

The series included the cases of fetal intracranial hemorrhage detected at our institution between 1992 and 1994 by transabdominal ultrasonography. In addition, we performed an English literature search (Medline computer search, National Library of Medicine) of all reported cases of a prenatal diagnosis of intracranial hemorrhage. The prenatal ultrasonographic findings were correlated with the clinical outcome, which was divided into (1) normal outcome or mild neurologic sequelae and (2) poor outcome (severe neurologic impairment and fetal or neonatal death).

RESULTS

Six cases of intracranial hemorrhage were detected in a population of 6641 pregnancies (0.9/1000) at our institution. Parenchymal involvement was present in three cases. Review of the English literature revealed 35 additional cases with prenatal ultrasonographic findings and postnatal follow-up. The total cases (n = 41) were divided into three groups: (1) isolated intraventricular hemorrhage (n = 20), (2) parenchymal hemorrhage (n = 13), and (3) subdural or subarachnoid hemorrhage (n = 8). Overall, poor outcome was present in 68% of cases, including 45% (9/20) of intraventricular hemorrhage, 92% (12/13) of parenchymal hemorrhage, and 88% (7/8) of subdural or subarachnoid hemorrhage. The heterogeneity of the intraventricular hemorrhage group in both severity of antenatal findings and outcome prompted us to devise a prognostic scoring system based on prenatal ultrasonographic lesions, grouping cohorts with similar outcomes. Outcome was favorable in 100% (5/5) of grade 1 intraventricular hemorrhage cases, in 50% (6/12) of grade 2 cases, and in 0% (0/3) of grade 3 cases.

CONCLUSIONS

Fetal intracranial hemorrhage can be classified on the basis of the anatomic location of the intracranial bleeding. The prognosis is poor in nearly 90% of parenchymal and subdural hemorrhages, whereas it is better in the subgroup with intraventricular hemorrhage. The prognostic scoring system we propose for intraventricular hemorrhage may assist the physician in providing patients with prognostic information.

Transabdominal amnioinfusion in oligohydramnios at term before induction of labor with intact membranes: a randomized clinical trial

OBJECTIVE

Our purpose was to determine the effectiveness of transabdominal amnioinfusion before induction of labor in reducing the incidence of fetal distress in pregnancies with oligohydramnios at term.

STUDY DESIGN

Between June 1991 and September 1994 primiparous women with ultrasonographic evidence of oligohydramnios at term, intact membranes, and unripe cervix (Bishop score < or = 6), candidates for induction of labor with cervical or vaginal prostaglandin E2 gel, were randomly selected to receive transabdominal amnioinfusion (amnioinfused group, n = 39) or to proceed with direct labor induction (control group, n = 40). Inclusion criteria were (1) singleton gestation, (2) vertex presentation, (3) ultrasonographic estimation of fetal weight > or = 2500 gm, and (4) reactive nonstress test. Fetoneonatal outcome variables were compared between the two groups. Statistical analysis used contingency tables, Student t test, or Wilcoxon rank-sum tests, where applicable.

RESULTS

Amnioinfusion was successfully performed in 100% of the patients randomized for the procedure. The incidence of severely abnormal fetal heart rate tracings was significantly higher in the control than in the amnioinfused group (42% [17/33] vs 5% [2/37], relative risk 12.9, 95% confidence interval 2.4 to 56.4). The rate of cesarean sections performed for fetal distress was fivefold higher in the control group (25% [10/40] vs 5% [2/39], relative risk 4.9, 95% confidence interval 1.1 to 32.4). No bleeding complications or fetomaternal infectious morbidity were noticed.

CONCLUSION

Transabdominal amnioinfusion is a safe, effective option for the prevention of fetal distress in pregnancies with oligohydramnios at term with intact membranes and unripe cervix.

Potential antitumor agents. 24. Synthesis and pharmacological behavior of imidazo[2,1-b]thiazole guanylhydrazones bearing at least one chlorine

In connection with a previous research dealing with the antitumor activity of imidazo[2,1-b]-thiazole guanylhydrazones, this paper reports the synthesis of new derivatives which were tested for antitumor and positive inotropic activity. In most cases the cytotoxic data from the in vitro experiments (HeLa) were in agreement with the antitumor data in vivo (Ehrlich). The active compounds bear a phenyl ring at the 6 position. On the other hand, the most active cardiotonic agents were devoid of the phenyl ring.

Characterization of ovine SRY transcript and developmental expression of genes involved in sexual differentiation

In mammals, the presence of SRY, the sex-determining gene located on the Y chromosome is required to induce the gonadal anlage to differentiate as a testis, whereas its absence leads to the development of an ovary. We report here the characterization by 5' and 3' RACE analysis of several SRY transcripts which are expressed in the ovine male developing gonads. These transcripts were not detected in any other fetal tissues and were expressed only in the genital portion of the urogenital ridge. The temporal profile of SRY expression analyzed by RT-PCR suggests that in the sheep fetus the role of SRY is not limited to initiating Sertoli cell differentiation as in mice. Indeed, SRY transcripts persist after the full differentiation of the testis. In addition to SRY, other genes are known to be involved in mammalian sex determination: Wilms' tumor gene WT-1, steroidogenic factor gene Ftz-F1 (SF-1) and anti-Müllerian hormone (AMH). We investigated the expression patterns of these genes by RT-PCR during fetal development in sheep gonads. Concerning WT-1 and SF-1, our results are consistent with those described in mice where the earliest expression was detected before the sexual differentiation in both sexes. In male, the ontogenesis of AMH transcription corresponds to the seminiferous cords formation (30 dpc). In female, we have observed the presence of SF-1 transcripts from the undifferentiated stage until birth. In addition, P450 aromatase expression is detected from 30 dpc and is correlated with the presence of 17-beta estradiol in sheep ovary. These data reveal significant differences between rodent and ruminant models concerning the sex-determining pathway.

Pineal microdialysis of the melatonin in conscious sheep: methodology, application to a diurnal rhythm and effect of isoproterenol

This paper describes the development of a new technique to measure melatonin contents in the pineal gland of moving sheep: the microdialysis. A dialysis probe was used to collect extracellular fluid in the sheep pineal gland, but also to inject directly into it different drugs such as isoproterenol at a very low concentration. The probe was implanted the day before the beginning of the experiment in order to obtain low levels of melatonin. This technique makes it possible to measure melatonin in the dialysate and plasma of rams submitted to 8L:16D. No melatonin either in the dialysate or in the plasma was found during the light phase. Shortly after lighting off, the melatonin concentration increased in the dialysate and plasma and remained stable during the dark phase. Melatonin concentrations began to decrease before lighting on and no detectable levels were found during the following light phase. The secretion of melatonin is, at least, under adrenergic regulation. Local infusion of isoproterenol (90 microliters at 10(-6) M), an agonist of beta adrenergic receptor, through the probe, increased melatonin levels during 2 h, even when infusions were repeated 3 times. This demonstrates the presence of beta adrenergic receptors. The technique presented in this paper could be of considerable interest for studying sheep pineal gland and its main secretion, melatonin, for example during diurnal rhythms or for studying its regulation.

Unorthodox antibiotic combinations including ciprofloxacin against high-level gentamicin resistant enterococci

Development of high-level gentamicin resistance among enterococci represents a serious therapeutic problem as it precludes synergy between aminoglycosides and cell-wall active agents. As part of a search for active antibiotic combinations against enterococci with high-level gentamicin resistance, we tested by the time kill curve method the efficacy of ciprofloxacin combined with ampicillin, trimethoprim-sulphamethoxazole, vancomycin or teicoplanin against ten isolates of Enterococcus faecium, three of Enterococcus casseliflavus and 13 of Enterococcus faecalis that exhibited a MIC of gentamicin > or = 2000 mg/L. Most of the E. faecium were also resistant to ampicillin and to ciprofloxacin. The combination of ciprofloxacin with ampicillin was bactericidal against five of seven E. faecium strains that exhibited a ciprofloxacin MIC < or = 4 mg/L, but was inactive against the three E. faecium that were highly resistant to ciprofloxacin. This combination was also bactericidal against the E. casseliflavus and all the E. faecalis strains. The combination of ciprofloxacin with trimethoprim-sulphamethoxazole was bactericidal against five of the seven E. faecium and seven of the nine E. faecalis strains with a ciprofloxacin MIC < or = 4 mg/L. No bactericidal activity of this combination was seen against the enterococci that were highly resistant to either ciprofloxacin or to trimethoprim-sulphamethoxazole. The combination of ciprofloxacin with glycopeptides was inactive against E. faecium and E. casseliflavus and against E. faecalis, it was either ineffective or antagonistic; in only one case it was bactericidal. Five strains of E. faecium were resistant to all antibiotic combinations tested.

Platelet composition and function in patients undergoing cardiopulmonary bypass for heart surgery

BACKGROUND

Previous studies showed severe biochemical and functional damage to platelets in patients undergoing cardiopulmonary bypass for cardiac surgery, and suggested that this derived from the proteolytic action of plasmin on the platelet surface.

METHODS

A double-blind study was carried out to compare platelet function and composition in patients randomized to receive the protease inhibitor aprotinin or placebo during reoperation for valvular prosthesis replacement or coronary artery bypass grafting.

RESULTS

Flow cytometry with specific monoclonal antibodies and polyacrylamide gel electrophoresis did not show any significant proteolysis of platelet glycoprotein Ib and IIb-IIIa either in the placebo or the aprotinin group. Functional studies were consistent with these results, since ristocetin-induced platelet agglutination was unchanged and platelet aggregation and ATP release induced by collagen and ADP were only slightly reduced by cardiopulmonary bypass. These mild defects in platelet function were partially prevented by aprotinin infusion.

CONCLUSIONS

On the basis of our data and those from literature, we suggest that platelets may be affected very little or severely damaged during cardiopulmonary bypass for cardiac surgery, probably depending on some aspects of the technical procedure which remain to be identified. Aprotinin infusion significantly protects platelets in the latter condition, while its role is obviously slight in the former.

Sexually transmitted diseases and risk of HIV infection

We have analyzed the association between sexually transmitted diseases (STD) and HIV infection, using data from a cross-sectional survey of subjects attending STD clinics in Northern Italy conducted since 1988. A total of 1,711 subjects (1,259 males, 452 females), who had referred themselves to three STD clinics in Northern Italy for suspected STD or STD treatment, were included for the study. Out of these, 145 subjects (113 males and 32 females) were HIV-positive. A total of 58 HIV-positive and 368 HIV-negative subjects reported a history of STD; the corresponding odds ratio (OR) was 2.3 (95% confidence interval (CI) 1.5-3.6) for subjects reporting a history of STD. Considering various STD in details, the estimated OR was 1.8 (95% CI 0.8-3.8) for a history of gonorrhoea and 1.5 (95% CI 0.8-2.7) of syphilis, and the OR was 1.8 (95% CI 1.0-3.2) and 2.2 (95% CI 1.3-3.8), respectively, for a positive TPHA and VDRL test. The results of the test for HbsAg were available in 50 HIV-positive and 1,028 HIV-negative subjects; the OR of HIV infection in subjects with HbSAg was 3.9 (95% CI 1.7-9.0). Presence of genital ulcers at clinical examination was not significantly associated with the risk of HIV infection (OR yes vs no genital ulcers 1.5, 95% CI 0.6-2.8).

Synthesis and fungicide activity of 2,3-dihydroimidazo [2,1-b]thiazole-5-carboxamides

The synthesis and characterization of carboxamides prepared from 6-substituted 1,1-dioxo-2,3-dihydroimidazo[2,1-b]thiazole-5-carboxylic acids is reported. The results from a fungicide test showed that the two most active amides are those arising from 2-aminopyridine.

Nature and bioactivity of gonadotropin-releasing hormone (GnRH) secreted during the GnRH surge

Previous studies have demonstrated a neural action of estradiol in inducing a surge of GnRH in the ewe. However, although the GnRH and LH surges began concurrently, the GnRH surge consistently continued well beyond the surge of LH. Three experiments were conducted to test the hypothesis that the termination of the LH surge results from the secretion of a relatively inactive variant of GnRH during the later phases of the GnRH surge. In the first experiment, hypophyseal portal blood collected during an estrogen-induced LH surge was analyzed for GnRH immunoreactivity using two antibodies having specificity for the N- or C-terminal portion of the GnRH molecule. The duration, amplitude, and time course of the GnRH surge were found to be similar irrespective of the antisera used. In a second experiment, a competitive GnRH antagonist was administered at the beginning of the estrogen-induced GnRH/LH surge at a dose capable of blocking pituitary responsiveness for approximately half the duration of the GnRH surge. Antagonist treatment did not result in any change in the time of onset of the GnRH surge, but there was no increase in LH that naturally occurs coincident with onset of the GnRH surge. Rather, a persistent increase in LH secretion was observed during the latter stages of the GnRH surge, indicating that the GnRH molecules secreted at this time were biologically active. Finally, a sensitive and specific ovine pituitary cell bioassay was used to test bioactivity of GnRH in hypophyseal portal blood during different phases of the GnRH surge. GnRH bioactivity in samples collected early in the GnRH surge was greater than that before the onset of the GnRH surge but no greater than that collected during the descending limb of the surge. The results of all three experiments fail to support the hypothesis that the LH surge ends because of a change in the nature of the GnRH secreted. Rather they show that GnRH secreted throughout the surge is biologically active. Thus, the termination of the LH surge before that of the GnRH surge occurs for reasons other than lack of a bioactive GnRH signal.

Resistance to aminoglycosides and other antibiotics among clinical isolates of Enterococcus spp

We conducted a study on 81 clinical isolates of enterococci (65 Enterococcus faecalis and 16 Enterococcus faecium) collected consecutively over a one year period at our University Hospital. Of them, 10 (15%) Enterococcus faecalis and 6 (38%) Enterococcus faecium showed high level resistance to aminoglycosides, were all acquired in surgical units and in five cases they were responsible for invasive infections. Ampicillin and imipenem were active only against Enterococcus faecalis. Vancomycin and teicoplanin were bacteriostatic; however, teicoplanin MICs were lower and in 45% of cases its MBC values were within clinically achievable serum concentrations. Ciprofloxacin and cotrimoxazole were active in vitro.

[Quantification and monitoring of vascular resistance in the lower limbs by the Doppler method (animal model)]

The object of this study was to define and validate a non-invasive method of evaluation and monitoring of vascular resistances in the leg. Blood flow velocity was measured by Doppler ultrasound in an animal model (ewe) with similar blood flow characteristics in the lower limb as man and allowing access to the required invasive measurements for validation of the method (pressure and flow). Vascular resistances distal to the measuring point (femoral, for example) were assessed using the resistance index R = D/S, S being the peak systolic deflection and D that of diastolic reflux of the Doppler spectral analysis of flow in the femoral artery. The values and variations of this resistance index were compared with the vascular resistances calculated from measurements of pressure and flow at the point of Doppler sampling and expressed in mmHg/ml/min. Femoral flow was measured by Doppler ultrasound (Doppler-echo), and mean pressure by an arterial catheter introduced into the abdominal aorta. Compression of the lower limb veins induced a venous return resulting in a reduction of cardiac output and femoral flow. During compression, femoral flow decreased by an average of 29% (p < 0.001) although mean pressure and heart rate did not change significantly. The femoral resistance index (Rf) increased by an average of 37.5% (p < 0.01) and vascular resistances increased by 45.9% (p < 0.01). Injection of 1 mg adrenaline induced peripheral vasoconstriction with an increase in blood pressure and a decrease in heart rate and femoral flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of luteinizing hormone-releasing hormone (LHRH) secretion by melatonin in the ewe. II. Changes in N-methyl-D,L-aspartic acid-induced LHRH release during the stimulation of luteinizing hormone secretion by melatonin

Injection of N-methyl-D,L-aspartic acid (NMDA), a glutamatergic agonist, cause an acute release of LH. The amount of LH released is modulated by photoperiod in sheep; it is larger in animals in which reproductive activity has been inhibited by long days than in those photostimulated by short days. The purpose of the present experiment was to determine whether this effect of photoperiod on LH response to NMDA is mediated by melatonin and whether it reflects a change in the amount of LHRH released in response to NMDA. Twenty-one ovariectomized ewes, bearing an s.c. implant of estradiol and kept in long days (16L:8D), received s.c. implants of melatonin on Day 0. The effect of a single injection of NMDA (5 mg/kg i.v.) on LHRH and simultaneous LH secretion was studied at three different periods of the stimulation of LH secretion by the melatonin treatment: first, during inhibition of LH secretion by long days (on Day -1, n = 6); secondly, during the onset of the LH increase (on Day 39, n = 9); and thirdly, during maximum LH secretion (on Day 74, n = 6). The stimulation of LHRH secretion by administration of NMDA was characterized by a large and long increase in LHRH concentration on Day -1 and Day 39. There was no significant difference between these two periods in terms of duration and amplitude of the LHRH release. On Day 74, the stimulation was much shorter than on Day -1 and Day 39 and was followed by a phase of decreased pulsatility of LHRH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of luteinizing hormone-releasing hormone (LHRH) secretion by melatonin in the ewe. I. Simultaneous delayed increase in LHRH and luteinizing hormone pulsatile secretion

This study was performed to test the hypothesis that a short-day-like melatonin treatment would induce simultaneous stimulations of LHRH and LH secretion. Simultaneous serial samples of jugular and portal blood to assay LH and LHRH, respectively, were carried out at three different periods according to the expected changes in LH secretion. Twenty-six ovariectomized ewes bearing a subcutaneous implant of estradiol and exposed to a long-day photoperiod (16L:8D) received s.c. implants of melatonin on Day 0. LHRH and LH pulsatile secretion was studied in the first group during inhibition of LH secretion by long days (on Day -1, n = 6). A second group (n = 9) was sampled on Day 39. Moreover, seven animals from this group were sampled on Day 46 to focus on the beginning of LH increase. The third group (n = 6) was sampled during maximal LH secretion (Day 74, n = 6). A fourth group (n = 5) composed of noncannulated animals was sampled for LH secretion only as a control for the effects of surgical procedures. On each occasion, blood was collected every 10 min for 6 h. Between Day -1 and Day 39, LHRH pulse frequency was low and did not differ. In the same animals, this value became 2.5-fold higher between Day 39 and Day 46. Finally, on Day 74, LHRH pulse frequency was about 6-fold higher than on Day -1.(ABSTRACT TRUNCATED AT 250 WORDS)

Thienylimidazo[2,1-b]thiazoles as inhibitors of mitochondrial NADH dehydrogenase

The synthesis of 6-substituted 5-(thienylvinyl)imidazo[2,1-b]thiazoles and 6-thienylimidazo[2,1-b]thiazoles is reported. These compounds were tested as specific inhibitors of the NADH: ubiquinone (UBQ) reductase activity of NADH dehydrogenase in mitochondrial membranes. The 6-thienylimidazo[2,1-b]thiazoles were more potent in mammalian than in nematode mitochondria and had an average titer of 0.11 mM for 2-methyl-6-(2-thienyl)imidazo[2,1-b]thiazole (10). This compound is noncompetitive with the ubiquinone substrate and interacts with a site which is mutually exclusive with that of rotenone but nonexclusive with that of piericidin and several other inhibitors of NADH dehydrogenase. In the series of 5-(thienylvinyl)imidazothiazoles, the hydrobromide of (E)-6-chloro-5-(2-thienylvinyl)imidazo[2,1-b]thiazole (E-5.HBr) was found to be more potent as an inhibitor of the NADH:UBQ activity (IC50 = 15-17 microM) than the 6-thienylimidazoles such as 10. The inhibitory action of E-5.HBr and its analogs is different from that of compound 10 as indicated by the mutual exclusivity with other inhibitors and the relative inhibition of the activity with various electron acceptors.

Intrauterine diagnosis and management of transient myeloproliferative disorder

Transient myeloproliferative disorders can be associated with hydrops in Down syndrome fetuses. No cases of prenatal management of such a condition have been reported in the literature. We report a case of myeloproliferative disorder diagnosed by cordocentesis at 31 weeks in a Down syndrome fetus with pericardial effusion. A pericardiocentesis was performed at the first signs of hydrops and successfully improved fetal cardiac function, allowing for continuation of pregnancy.

Bilateral lesions of the suprachiasmatic nuclei alter the nocturnal melatonin secretion in sheep

The hypothalamic suprachiasmatic nuclei (SCN) constitute both the biological clock of many circadian rhythms, and the first relay in the transmission of light cues from the retina to the pineal gland, which releases, via nocturnal melatonin secretion, an endocrine expression of the daylength. The aim of the present work was to investigate the precise role of the SCN in the entrainment of the nocturnal rhythm of melatonin (MEL) in sheep. Bilateral lesions of the SCN were performed via a transsinusal surgical approach in 10 adult rams submitted to a constant photoperiod (16:8D). Lesioned rams were compared to 4 sham and 2 control animals. Blood samples were collected 8 days before, 8 days after, and one month after surgery. Plasma MEL levels were estimated using direct radioimmunoassay. At the end of the experiment, histology and immunohistochemistry of the suprachiasmatic area were performed, and the extent of lesions was evaluated using a computerized image analysis system. Six rams exhibited a complete lesion of the SCN, and in the four remaining animals, the lesions were restricted to the anterior part of the SCN. For all animals, the nocturnal melatonin secretion was altered, but depending on the extent of the lesion, two types of results were observed: Eight days after surgery, in 3 of the 4 rams bearing anterior lesions of the SCN (SCNx-), a nocturnal increase in melatonin secretion still occurred at dusk, but the duration of this secretion extended beyond the end of the night. One month after surgery, melatonin profiles were once again normal, as compared to sham animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of the main but not the accessory olfactory system in maternal behavior of primiparous and multiparous ewes

The respective roles of the main and accessory olfactory systems in the development of maternal behavior and selective suckling were investigated in parturient primiparous and multiparous ewes. Vomeronasal nerve section before parturition did not disturb either maternal behavior or maternal selectivity at suckling. By contrast, anosmia induced by zinc sulphate infusion had significant effects on the onset of maternal behavior in primiparous ewes. The onset of licking and of suckling were delayed and licking times and maternal bleats were reduced. Such disturbances were not observed in multiparous anosmic ewes, indicating that experience can compensate for the loss of olfactory information. On the other hand, anosmia prevented selective care regardless of maternal experience. Our results underline the importance of the main olfactory system for the development of adequate maternal behavior in sheep.

Effects of gonadotrophin deprivation on follicular growth in gilts

The endocrine and ovarian effects of hypophysectomy (n = 5) and gonadotrophin-releasing hormone (GnRH) antagonist administration (Antarelix) (n = 5) were studied in gilts by comparison with control animals (n = 6). All gilts were given Regumate (20 mg/d for 18 d). The last day of Regumate was day 0. Hypophysectomy and initiation of Antarelix administration (0.6 mg iv twice daily for 7 d) were performed on day 5. All ovaries were obtained at slaughter on day 12. Blood samples were obtained daily from all Antarelix-treated and control sows to measure luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations. Frequent sampling was performed on day 10 on control and Antarelix-treated gilts to assess pulsatile LH secretion. Oestrus or LH surge was initiated before the beginning of treatment in 2 hypophysectomized, 4 Antarelix-treated, and 4 control females. Gonadotropins were undetectable in the blood of hypophysectomized sows on day 6. On day 10, pulsatile LH release was blocked in Antarelix-treated gilts. At no time were FSH concentrations significantly affected. Histological observation of the ovaries demonstrated that: (i) similar populations of healthy or total (healthy + atretic) follicles < 1 mm were found in the 3 groups of females; (ii) healthy follicles 1 to 2 mm in diameter were present in Antarelix-treated but not in hypophysectomized gilts; and (iii) healthy follicles > 2 mm were absent in Antarelix-treated and hypophysectomized gilts. The present study suggests the existence of 3 subgroups amongst antral follicles (gonadotropin independent: 0.19 to 1.1 mm; FSH dependent: 1.1 to 2 mm; LH pulses dependent: > 2 mm in diameter).

Vascular resistance quantification in high flow resistance areas using the Doppler method

The objective of the present study is to define and validate on an animal model (ewe) a new Doppler parameter for the assessment and monitoring of the vascular resistances in high resistance to flow areas (lower limbs, placenta with vascular disease). The high resistance index (HRI) was derived from the transmission line theory and defined as: HRI = D/S with S the amplitude of the systolic peak and D that of the diastolic reverse flow. Validation of the HRI was performed on adult ewes. Distal lower limb vascular resistances were evaluated from the Doppler femoral waveform (HRI) and compared with the classic vascular resistances (Rv), calculated from pressure and flow (mmHg/mL/min). The femoral flow variations were measured by duplex (echo-Doppler) method and the mean pressure through an arterial catheter inserted into the abdominal aorta. Two tests were used in this study: (1) A calibrated venous compression of the lower limbs extremity: The femoral flow dropped by 29%, the pressure and heart rate did not change, the HRI increased by 37% (p < 0.01), and the vascular resistance (Rv) by 46% (p < 0.01). (2) The intravenous injection of 1 mg adrenaline: The arterial pressure increased by 70% (p < 0.001), the heart rate and femoral flow dropped by 50% (p < 0.001), and 35% (p < 0.001), the HRI increased by 70% (p < 0.01) and the vascular resistances (Rv) by 140% (p < 0.01). During the two tests, the HRI changed in proportion with the "classic" vascular resistances.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogenesis of somatic and germ cells in sheep fetal testis

Testicular development of sheep fetuses was studied between day 42 of gestation and birth. Testis mass and the total number of testicular cells increased curvilinearly with fetal age and a positive linear relationship was established between the logarithmic values of age and testis mass, sex cord total length, total number of Sertoli cells, germ cells and Leydig cells per testis. The mean number of gonocytes per unit length of sex cord, the Sertoli cell nuclear cross-sectional area and the Leydig cell cross-sectional area decreased linearly with age between day 42 of gestation and birth. Hypophysectomy and hemicastration were performed to study the regulation of testicular cell divisions during fetal life and to determine whether they were under pituitary control and whether a feedback mechanism was present. Hypophysectomy at day 100 or 110 of gestation nonsignificantly decreased (0.05 < P < 0.01) the testis mass, total length of sex cords and total number of Sertoli cells and significantly decreased (P < 0.05) the cross-sectional area of Leydig cells and nuclei of Sertoli cells. Sex cord diameter and total number of gonocytes were unaltered. Hemicastration at day 110 of gestation significantly increased (P < 0.05) the total number of Leydig cells per testis without changing any other testicular parameter. In male sheep fetuses, the proliferation of testicular somatic and germ cells occurs throughout testicular fetal growth at a higher rate before day 100 of gestation than later, but without any differentiation. Mitotic divisions of Sertoli cells are more numerous before birth than afterwards. Before birth, the proliferation of gonocytes is not under pituitary control.

Assessment of the fetal PO2 changes by cerebral and umbilical Doppler on lamb fetuses during acute hypoxia

The objective of the present study was to validate one or a combination of fetal Doppler parameters in order to assess acute fetal hypoxia in an ovine model. Acute hypoxia was induced by reducing umbilical, or maternal aortic flow (approx. 70%). A CW Doppler probe was fixed on the fetal cervical skin, facing the internal carotid artery and the fetal abdominal skin adjacent to the umbilical arteries. (The angle between Doppler beam and flow vector remained constant.) A "Doptek 3000" spectrum analyser was used to measure the maximal and mean Doppler frequencies. Heart rate (HR), umbilical blood flow (UBF), carotid blood flow (CBF), umbilical RI (URI), cerebral RI (CRI) and cerebroplacental ratio (CPR = CRI/URI) were calculated in real time. A catheter was inserted into the fetal femoral artery, for blood gas (PO2, PCO2 pH) and blood pressure (BP) measurements. After 1 min of aorta compression (70% aortic flow reduction), the URI increased by 10% (P < 0.05), and the UBF decreased by 10% (P < 0.05), but the CRI decreased by 20% (P < 0.02), and the CBF did not change significantly. Fetal PO2 and CPR fell down after 1 min (59% and 38%, respectively; P < 0.001), although strong fetal heart rate decelerations were observed. The blood pressure, PCO2 and pH did not change significantly during this test. Throughout the 12 min of cord compression (70% umbilical flow reduction) the URI increased (70% to 80% P < 0.001), and the UBF decreased (approx. 60%; P < 0.001), but the CRI decreased (approx. 25%; P < 0.01), and the CBF remained constant (+/- 5%; ns). Fetal PO2 and CPR all decreased during the compression (30% to 44% and 40% to 60%, respectively; P < 0.001). HR, pH and PCO2 did not change significantly. During cord compression the blood pressure did not change significantly. In both cases, the CPR decreased significantly (P < 0.001) with the PO2 in the same direction and with a comparable amplitude (-30% to -50%). Nevertheless, the drop in CPR was greater during cord compression than during aorta compression, probably because the compression of the cord induced a central hypovolemia in addition to the hypoxia. The CPR was found to be the hemodynamic parameter that followed most closely the PO2 acute changes. The amplitude of the variations of this parameter (-30% to -50%) were quite similar to those of the PO2 during the period of acute hypoxia.(ABSTRACT TRUNCATED AT 400 WORDS)

Antitumor and cardiotonic activity of imidazo[2,1-b]thiazole guanylhydrazones

A number of imidazo[2,1-b]thiazole guanylhydrazones, whose antitumor activity has already been described, were tested as potential cardiotonic agents. The guanylhydrazone of 2,3-dihydro-6-chloroimidazo[2,1-b]thiazole-5-carboxaldehyde (2a) was the most interesting compound showing both antitumor and cardiotonic activity.

The suprachiasmatic nucleus in the sheep: retinal projections and cytoarchitectural organization

The retinal innervation, cytoarchitectural, and immunohistochemical organization of the suprachiasmatic nucleus (SCN) was studied in the domestic sheep. The SCN is a large elongated nucleus extending rostrocaudally for roughly 3 mm in the hypothalamus. The morphology is unusual in that the rostral part of the nucleus extends out of the main mass of the hypothalamus onto the dorsal aspect of the optic chiasm. Following intraocular injection of wheat-germ agglutinin-horseradish peroxidase or tritiated amino acids, anterograde label is distributed throughout the SCN. Retinal innervation of the SCN is bilaterally symmetric or predominantly ipsilateral. Quantitative image analysis demonstrates that, although the amount of autoradiographic label is greatest in the ventral and central parts of the nucleus, density varies progressively between different regions. In addition to the SCN, retinal fibers are also seen in the medial preoptic area, the anterior and lateral hypothalamic area, the dorsomedial hypothalamus, the retrochiasmatic area, and the basal telencephalon. Whereas the SCN can be identified using several techniques, complete delineation of the nucleus requires combined tract tracing, cytoarchitectural, and histochemical criteria. Compared with the surrounding hypothalamic regions, the SCN contains smaller, more densely packed neurons, and is largely devoid of myelinated fibers. Cell soma sizes are smaller in the ventral SCN than in the dorsal or lateral parts, but an obvious regional transition is lacking. Using Nissl, myelin, acetylcholinesterase, and cytochrome oxidase staining, the SCN can be clearly distinguished in the rostral and medial regions, but is less differentiated toward the caudal pole. Immunohistochemical demonstration of several neuropeptides shows that the neurochemical organization of the sheep SCN is heterogeneous, but that it lacks a distinct compartmental organization. Populations of different neuropeptide-containing cells are found throughout the nucleus, although perikarya positive for vasoactive intestinal polypeptide and fibers labeled for methionine-enkephalin are predominant ventrally; neurophysin-immunoreactive cells are more prominent in the dorsal region and toward the caudal pole. The results suggest that the intrinsic organization of the sheep SCN is characterized by gradual regional transitions between different zones.