Development of arteriovenous anastomoses in Rattus norvegicus species during the fetal period

In this study carried out on the development of arteriovenous anastomoses (AVAs) in Rattus norvegicus species, the fetus was followed up 10 days after post coitum (pc). The sections obtained from the fetuses of 10-20-day rats were subjected to the usual processes for examination under the light microscope. Various staining processes were applied on the preparations and the simple and glomus types of AVAs determined in the mesenchyme of fetuses observed to birth every day. The regions with AVAs were then photographed by photomicroscopy and evaluated. From the 10-day embryo to birth, an increase in the smooth muscles in the wall structure of simple anastomoses was observed. It was however very difficult to follow up this increase in glomus anastomoses because the wall structure is more complicated. Their morphology was examined and compared with that in literature.     

Mechanisms underlying spinal motor neuron excitability during the cutaneous silent period in humans

The transient suppression of muscle contraction during the cutaneous silent period (CSP) could be produced either through postsynaptic inhibition of motoneurons or through presynaptic inhibition of the excitatory inputs to motoneurons that sustain voluntary contraction. We sought to delineate the mechanisms underlying the CSP in hand muscles by measuring changes in H-reflexes and motor-evoked potentials (MEPs) produced by transcranial magnetic stimulation (TMS) during the CSP in 10 healthy volunteers. H-reflexes and MEPs both measure the excitability of the motoneuron pool and activate similar subpopulations of motoneurons through different pathways. Inhibition of H-reflexes and MEPs of similar size was maximal at the midpoint of the CSP and gradually returned to baseline. The similar time course of recovery suggests that the H-reflex and MEP are affected by inhibition at a common site, most likely postsynaptic inhibition of the motoneurons.     

Vitamin and mineral transfer during fetal development and the early postnatal period in pigs

There are periods during pregnancy when sows may have a temporally high requirement for certain vitamins and minerals. Proteins transferring retinol and Fe to the developing pig fetus have been discovered, whereas transport mechanisms for other vitamins and minerals are probably present but have not yet been identified. Sow body tissues can serve as a reservoir for many micronutrients, but it is not known whether these reserves can supply an adequate quantity during critical fetal developmental periods. There is a low placental transfer of vitamin E to the fetus even if the dietary concentration fed to a gestating animal is high, but colostrum and milk concentrations can be increased when the nutrient is fed to sows. If the dam's diet contains inadequate Ca or P, the concentration of these elements in the developing fetus and milk will not be affected. Consequently, sow bone demineralization will occur under conditions of dietary inadequacy of Ca and P. Other nutrients can be depleted from sow tissue reservoirs over several parities (e.g., Se), resulting in low quantities being provided in the milk for nursing pigs. Scientific information involving adequate vitamin and mineral nutrition for female pigs to improve conception rate and embryonal survival that will result in optimum fetal and postnatal pig development can be considered to be in its infancy.     

Immunohistochemical localization of androgen receptor in mouse testicular germ cells during fetal and postnatal development

BACKGROUND: Determination of the cellular distribution of the androgen receptor (AR) in testicular cells is necessary for understanding the mode of AR action in the testis. We here investigated immunohistochemically the localization of AR by use of anti-human AR polyclonal antibody NH27, with special reference to the AR in germ cells in the developing mouse testis. METHODS: ICR mouse testes taken from day 14 post coitum (p.c.) to day 56 post partum (p.p) were used for AR immunohistochemistry by the routine immunoperoxidase method at the light microscopic level and the pre-embedding method at the electron microscopic level. RESULTS: On day 14 p.c., AR immunoreactivity was present in nuclei of prospermatogonia but not in those of Sertoli cells or interstitial cells. On day 14 p.p., the AR was detected in the nuclei of spermatogonia, Sertoli cells, and myoid cells. AR immunoreactivity in nuclei of Leydig cells appeared on day 21 p.p. In the mature mouse testis, the AR was present in the nuclei of spermatogonia, Sertoli cells, myoid cells, and Leydig cells. CONCLUSIONS: AR was present both in germ cells and in somatic cells during fetal and postnatal development of the mouse testis. In the fetal testis, AR was localized exclusively in prospermatogonia and spermatogonia, suggesting that androgen may act directly on germ cells during prespermatogenesis and the early stage of spermatogenesis. Based on the fact that AR is expressed in Sertoli cells, myoid cells, and Leydig cells around the onset of spermatogenesis, the regulation of AR expression in the germ cells seems to be different from that in the somatic cells. Furthermore, our present data suggest the ultrastructural localization in nuclei of mouse testicular cells is similar to that of some other steroid receptors, both in germ cells and somatic cells.     

Autonomous cell death of mouse male germ cells during fetal and postnatal period

OBJECTIVE: To determine the utility of CT-determined main pulmonary artery diameter (MPAD) for predicting pulmonary hypertension (PH) in patients with parenchymal lung disease. DESIGN: Retrospective review of right-heart hemodynamic data and chest CT scans in 45 patients. SETTING: Tertiary-referral teaching hospital and VA hospital. PATIENTS: Between October 1990 and December 1995, 36 patients referred for evaluation of parenchymal lung disease or possible pulmonary vascular disease were found to have PH, as defined by mean pulmonary artery pressure (mPAP) > or =20 mm Hg. Nine control patients (mPAP <20 mm Hg) were also identified (4 from hospital records search, 5 after evaluation for possible PH). RESULTS: CT-determined MPAD was 35+/-6 mm in patients with PH and 27+/-2 mm in control subjects. In our group of patients, MPAD > or =29 mm had a sensitivity of 87%, specificity of 89%, positive predictive value (PPV) of 0.97, and positive likelihood ratio (LR) of 7.91 for predicting PH; in the subgroup of patients with parenchymal lung disease (n=28, PH and control subjects), MPAD > or =29 mm had a sensitivity of 84%, specificity of 75%, PPV of 0.95, and positive LR of 3.36 for predicting PH. The most specific findings for the presence of PH were both MPAD > or =29 mm and segmental artery-to-bronchus ratio > 1:1 in three or four lobes (specificity, 100%). There was no linear correlation between the degree of PH and MPAD (r=0.124). CONCLUSIONS: CT-determined MPAD has excellent diagnostic value for detection of PH in patients with advanced lung disease. Therefore, standard chest CT scans can be used to screen for PH as a cause of exertional limitation in patients with parenchymal lung disease. Because CT is commonly used to evaluate parenchymal lung disease, this information is readily available.     

Chronological changes in autoantigenicity of autologous testicular germ cells in C3H/He mice during the postnatal period

Our recent studies demonstrated that experimental autoimmune orchitis (EAO) model was produced in C3H/He mice with high incidence by two subcutaneous injections of viable syngeneic testicular germ cells (TC) without the use of any adjuvants or immunopotentiators. In this study the developmental patterns of autoantigenicity of TC during postnatal period were investigated by examining the orchitogenic activity of TC, the lymphostimulatory activities of TC (including the TC-induced in vitro lymphocyte proliferative response and the cytokine release from sensitized spleen cells (SPC) in response to TC) and the immunohistochemical localization of target autoantigens in the testes of mice at various weeks of age. Delayed-type hypersensitivity-inducing capacity and anti-TC antibody-eliciting capacity were initially observed in mice that were immunized with TC of 4-week old (w.o.) mice. The TC from 6-w.o. mice had the capability of inducing EAO (orchitogenicity) for the first time. A significant stimulation of in vitro lymphocyte proliferative response, as well as of interleukin (IL) 5 and IL-6 production by sensitized SPC were detectable when TC of mice 3-w.o. or more than were employed as stimulant. IL-2 and interferon gamma production were detected with TC of 4-w.o. mice. Immunohistochemical staining reaction with anti-TC antisera was primarily localized at the acrosomal portion of spermatids and spermatozoa in the seminiferous tubules, being already detected in spermatids of as early as 3-w.o. mice. Thus, from these data it is suggested that the appearance of the lymphostimulatory activities of TC consistently precedes that of the orchitogenic activity and that relatively mature germ cells such as spermatids and spermatozoa developing in the testes during the postnatal weeks may be responsible for the induction of disease and relevant immune responses in our EAO system.     

Nonstressed fetal heart rate monitoring in the antepartum period

The role of nonstressed monitoring of the fetal heart rate (HR) in determining fetal well-being during the antepartum period was assessed in 125 high-risk patients. Observations on HR, variability, and HR response to fetal movement (FM) and uterine contractions (UC) over a 30 minute period were made with an external microphone and tocotransducer. A total of 625 tests were performed; the earliest gestation tested was 28 weeks, and the latest was 46 weeks. A reactive pattern (variability greater than 6 b.p.m. and accelerations with FM) appears to be a reliable indicator of fetal well-being. All the 51 fetuses exhibiting this pattern survived. This group also had the lowest incidence of neonatal complications. On the other hand, of the babies who failed to show variability greater than 6 b.p.m. or accelerations with FM (nonreactive pattern), 40% died in the perinatal period. Thirty-five patients showed features of both a reactive and nonreactive pattern (combined pattern). Poor outcome in this group was confined to those in whom the majority of the pattern was nonreactive. An undulating HR pattern with virtually absent variability (sinusoidal pattern) was found in 20 Rh-sensitized fetuses, 50% of whom died in the perinatal period. Bradycardia and tachycardia were not found to be reliable signs of fetal distress antepartum. Of the 12 fetuses who died during observation, six showed late decelerations with spontaneous UC but all showed diminished variability. The close correlation between nonstressed patterns and neonatal outcome demonstrated by this preliminary study warrants further use of this technique for fetal evaluation.     

A case of infant testicular tumor diagnosed ultrasonographically in the prenatal period

We report a case of testicular tumor detected by ultrasonography during the prenatal period. Ultrasonography performed at 32 weeks of gestation showed that one testis was larger than the other. The right testis was markedly enlarged at 38 weeks of gestation. The heterogeneous echo pattern of the right testis suggested a testicular tumor. Right high orchiectomy was performed 3 months after birth. Pathological findings of the tumor were teratoma with mature and immature components according to the histological classification of testicular tumor. In Japan, this is the second case diagnosed in the prenatal period using ultrasonography.     

Development of ascending colon in human fetal period

Study of glucose and xylose utilization by Pichia stipitis in a limited oxygen supply condition revealed that the rate of glucose utilization decreased rapidly while that of xylose decreased slowly until the time that glucose and xylose were shown to level out, at which point the rate of xylose utilization increased rapidly. Based on the results, ethanol fermentation technology in continuous connective tower fermenters was advanced, e.g., fermentation by P. stipitis in an airlift loop tower focusing on xylose utilization and then residue glucose utilization by Saccharomyces cerevisiae in an overflow tower. When the fed hydrolyzate of bagasse was concentrated in five folds and the dilution rate was 0.1 h-1, the total utilization ratio of reducing sugar was 97.2%; the concentration of ethanol was 46.4 g/L.h.     

Changes in plasma lipids and lipoproteins in humans during a 2-year period of dietary restriction in Biosphere 2

BACKGROUND: A cohort study was performed of 8 people sealed inside Biosphere 2 to evaluate the effects of dietary restriction in humans on lipid and lipoprotein levels and the relationship of these levels to energy, fat, and protein content of the diet, and body weight, weight change, and energy expenditure. METHODS: Eight healthy people aged 27 to 67 years, 4 women and 4 men, were sealed inside Biosphere 2 from September 26, 1991, to September 26, 1993, the longest sustained period in an "isolated confined environment" on record. They were studied throughout confinement and for more than 2 years after their exit and return to an ad libitum diet. Food available was severely restricted during most of the 2-year period inside Biosphere 2. High work output was maintained and food quality remained high, resulting in prolonged restriction of energy intake without malnutrition. RESULTS: Fasting plasma cholesterol, triglyceride, and high-density lipoprotein (HDL) cholesterol levels; HDL subfraction distribution; dietary energy, fat, and protein content intake; and height, weight, weight change, and energy expenditure were measured. Total plasma cholesterol and triglyceride levels decreased 30% and 45%, respectively. The HDL and low-density lipoprotein levels also decreased and, in some participants, levels of HDL2 subfractions were increased. Multivariate analysis showed that the major cause of these changes was energy restriction. CONCLUSIONS: Energy restriction was the major factor leading to low lipid and lipoprotein levels. Energy restriction with adequate nutrition of young and middle-aged people may substantially reduce risk for atherosclerosis and consequent coronary artery and cerebrovascular disease.     

Placental transfer and fetal uptake of 3H-digoxin in humans

Placental transmission and fetal distribution of 3H-digoxin were studied in seven pregnant women undergoing legal termination of pregnancy during the first half of gestation. The radioactivity in fetal and maternal plasma and in fetal tissues was estimated using the oxidation method, and the integrity of the labelled drug by thin layer chromatography. The 3H-digoxin activity was clearly demonstrated in the umbilical cord blood five minutes after injection of the drug into the maternal blood, and the fetal plasma concentrations of 3H-digoxin approximated to the maternal value 30 minutes after drug administration. The distribution of 3H-digoxin in the fetal tissues was relatively even, with the highest 3H concentrations found in the heart and placenta, the lowest in the brain. The results suggest that the capacity of human fetal heart to bind digoxin during the first half of gestation is limited.     

The serum kinetics of bovine testicular hyaluronidase in dogs, rats and humans

There is experimental and clinical evidence that i.v. injection of bovine testicular hyaluronidase (BTH) reduces the extent of necrosis during myocardial infarction. The fate of i.v. administered BTH has not been described. In this study, serum kinetics of BTH enzyme activity in dogs, rats and humans were determined. Tissue distribution of BTH was determined with an 125I-labeled preparation of purified BTH. Serum BTH activity initially decreased exponentially with half-life 2.0 +/- 0.1 min in dogs with coronary artery occlusion (n = 8; 500 U of BTH/kg); 3.2 min in humans with acute myocardial infarction (n = 2; 500 U of BTH/kg); and 3.2 +/- 0.3 min in rats (n = 5; 5,000 U of BTH/kg). In dogs BTH disappearance showed two distinct phases. After injection of high dose BTH (5,000 U of BTH/kg), during the first 7 min serum half-life of BTH was 2.1 +/- 0.2 min (n = 8), but increased to 9.4 min in later serum samples. After the injection of 125I-labeled BTH into the rat, protein-bound 125I disappeared from serum with a half-life (3.4 min) that is similar to the serum half-life of BTH enzyme activity (3.2 min). Twenty minutes after injection of 125I-labeled BTH, 30% of the label was recovered in the liver. It is concluded that BTH activity has a short serum half-life of less than 10 min in dogs, rats and humans. In the rat model, the disappearance of serum BTH activity results from physical removal of circulating BTH molecules rather than serum inhibition or inactivation of BTH enzymatic activity.     

Variation in the masseteric silent period in older dentate humans and in denture wearers

The masseteric silent period was elicited by chin taps at 40% clenching in the masseter muscle of the preferred chewing side in 22 younger dentate individuals, in 22 older dentate individuals, in 22 older experienced denture wearers and in 7 older inexperienced denture wearers. One simple and three combined types of silent period (combination of early and late phases of depression) were recorded in all groups. An early silent period was always elicited, the only exception being in some inexperienced denture wearers. Both the age and the extent of rehabilitation with dentures in the trained denture wearers affected reflex latencies (p < 0.05), while the variation in duration was not significant (p > 0.05). The duration of the silent period was, however, affected by the type of silent period, thus by the measuring technique (p < 0.05). Increased variation was observed in the inexperienced denture wearers, who were in a period of adaptation.     

Effect of overfeeding during the dry period on regulation of adipose tissue metabolism in dairy cows during the periparturient period

During the dry period, cows were either fed restricted amounts or were overfed to study lipolytic rates in adipose tissue. Higher lipolytic rates can result in greater accumulation of triacylglycerols in liver and, subsequently, hepatic lipidosis. Adipose tissue was biopsied at -1, 0.5, 1, 2, and 3 wk from parturition. The basal in vitro lipolytic rate was measured as well as the lipolytic rate as affected by the addition of noradrenaline, 3-hydroxybutyrate, or glucose. Liver was biopsied to quantify triacylglycerol concentrations. Blood was collected to determine insulin and nonesterified fatty acid concentrations. Basal in vitro lipolytic rates at -1 and 0.5 wk were lower in overfed cows. Lipolytic rate was enhanced in both groups of cows when noradrenaline was added, but rates at -1 and 3 wk tended to be higher in overfed cows than in cows that were fed restricted amounts. After the addition of 3-hydroxybutyrate or glucose in vitro, lipolytic rates tended to be higher in overfed cows. Liver triacylglycerol concentration was higher in overfed cows at 0.5 and 1 wk. Plasma insulin concentration tended to be higher in overfed cows at -1 wk. Plasma nonesterified fatty acid concentration was higher in overfed cows at 0.5 and 1 wk. Although overfeeding compared with restricted feeding did not significantly alter the in vitro lipolytic response to 3-hydroxybutyrate or glucose, adipose tissue from overfed cows tended to be less inhibited by these substances, which may contribute to higher lipolytic rates in vivo and a greater triacylglycerol accumulation in the liver after parturition.     

Prevention of neonatal respiratory distress syndrome through the administration of prednisolone in the fetal period

The clinical effectiveness of antenatal prednisolone medication (prednisolone hemisuccinate) for the prophylaxis of idiopathic respiratory distress syndrome (IRDS) was studied in 114 premature infants with a gestational age between 28 and 36 weeks. There was a statistically significant difference (chi2 - test, p less than 0,01) between the frequency of IRDS in this group and in another one consisting of 137 premature babies with a nearly identical distribution of gestational age, whose mothers did not get prednisolone before delivery. It could be shown that the time interval between medical induction and delivery should not exceed 2 weeks, since the effect decreases with time. At present prednisolone medication during the fetal period may serve as useful prophylactic measure for IRDS in cases of premature birth. As there are a lot of contraindication against prednisolone and as we do know very much about side effects, it seems necessary to seek for other, less dangerous inductors.     

Medication use during the perinatal period

OBJECTIVE: To briefly describe the drug therapy administered during the perinatal period of pregnancy for common maternal and fetal complications, and to identify those agents that should not be used for these conditions. DATA SOURCES: References were obtained from an ongoing literature search of peer-reviewed obstetric and gynecologic journals and other selected medical and pharmacy journals available in the English language. Primary search vehicle was a weekly review of the tables of contents of nearly 1,300 medical journals provided by Reference Update (Institute of Scientific Information, Philadelphia). MEDLINE searches were also conducted using key terms for each subtopic. STUDY SELECTION: Specific references were selected for each topic based on the adequacy of their study design, patient population, and a recent publication date. Reviews were used if a large number of primary references would have been required to adequately describe the topic. DATA EXTRACTION: Most references reflected the current opinions expressed in the Educational (Technical) Bulletin and Committee Opinion series published by the American College of Obstetricians and Gynecologists. Recent, well-conducted studies that arrived at different conclusions were also included. DATA SYNTHESIS: Data obtained from each reference reflected the conclusions of the authors based on their research or an analysis of the research on others on the appropriate use of the drug(s) for the specific condition being treated. CONCLUSION: Drug therapy during the perinatal period is frequently required and can be beneficial for the mother, fetus, and newborn. Many complications previously associated with severe morbidity and mortality, such as infections, premature rupture of membranes, preterm labor, hypertension, maternal pain during labor, and postpartum hemorrhage, are now controlled with appropriate pharmacologic therapy. All health professionals who provide services to pregnant women should be knowledgeable in this drug therapy.     

Characteristics of the muscle mechanoreflex during quadriceps contractions in humans

We examined muscle sympathetic nerve activity (MSNA) in the nonexercising lower limb during repetitive static quadriceps contraction paradigm at 25% maximal voluntary contraction in eight men. Subjects performed 20-s contractions with 5-s rest periods for up to 12 contractions. Although the workload was constant, we found that MSNA amplitude rose as a function of contraction number [0.6 ln (amplitude/min)/contraction]; this suggests chemical sensitization of the muscle reflex response. We employed signal-averaging techniques and then integrated the data to examine the onset latency of the MSNA response as a function of the 25-s contraction-rest period. We observed an onset latency of approximately 4-6 s. Moreover, although the onset latency did not appear to vary as a function of contraction number, the rate of MSNA increase took approximately four contractions to reach a steady-state rate of rise; this suggests contraction-induced sensitization. The onset latency reported here is similar to findings in recent animal studies, but it is at odds with latencies determined in prior human handgrip contraction studies. We believe our data suggest that 1) mechanically sensitive afferents contribute importantly to the MSNA response to the paradigm employed and 2) these afferents may be sensitized by the chemical products of muscle contraction.