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.     

Effect of GABA on motor activity in the rat during the early postnatal period

Effect of GABA on the motor activity of rats of the first month of life was studied in conditions of free behaviour in the maternal cage. It has been found that at the age of 1-10 days the injection of GABA increases, and at the age of 11-30 days decreases both the general motor activity and the grooming activity. It is suggested that a possible mechanism of the observed effect of GABA consists in the deepening of presynaptic inhibition, which results, during the earlier stages of postnatal ontogeny, in intensifying the autorhythmical activity of spinal motor centres, whereas during the later stages, when the autorhythmical activity of the spinal cord is replaced by reflex excitatory mechanisms, in depressing the latter.     

Adipose tissue development during early postnatal life in ewe-reared lambs

This study examines the precise time course that brown adipose tissue (BAT) takes to adopt the characteristics of white adipose tissue in postnatal lambs. Perirenal adipose tissue was sampled from ewe-reared lambs within 1 h of birth and at 1, 2, 4, 7, 14, 21 and 30 days of age and analysed for the amount of mRNA for uncoupling protein (UCP), the amount and activity of UCP, and protein, mitochondrial protein and lipid content. This was combined with measurements of colonic temperature and jugular venous plasma concentrations of thyroid hormones and insulin-like growth factor-1 (IGF-1). Over the first 4-7 days of age, large quantities of UCP mRNA were associated with a peak in plasma triiodothyronine concentration at 2 days of age followed by a maximal amount and activity of UCP at 4 days and a basal colonic temperature of 39.3 degrees C. Between 7 and 30 days there was a large increase in lipid deposition as the amount and activity of UCP and the amount of UCP mRNA declined to basal values and colonic temperature was maintained at 40 degrees C. A significant positive relationship between perirenal adipose tissue lipid content and plasma IGF-1 concentration was observed throughout the study period. It is concluded that ovine adipose tissue maturation occurs in two distinct phases over the first month of life. The precise time scale of this process could be regulated in part by the lamb's body temperature which determines whether adipose tissue is required for heat production (i.e. BAT) or as an endogenous energy source (i.e. white adipose tissue).     

Acinar cell responsiveness to urecholine in the rat pancreas during fetal and early postnatal growth

These studies were performed to determine when, during fetal or postnatal life, rat pancreatic acinar cells acquire their capacity to respond to cholinergic drugs. The release of amylase, lipase, and chymotrypsin from rat pancreas in response to urecholine was measured in vitro. Fetal and newborn pancreas did not respond to 10(-5) M urecholine; 3-day- to 15-day-old pancreas demonstrated an increasing response to this dose. Peak sensitivity when compared to adult pancreas was present between days 15 and 21. Our results indicate that the exocrine pancreas acquired a responsiveness to urecholine on the 3rd day of postnatal life and becomes more sensitive to stimulation from the 15th day.     

Controlling factors in the development of ceruloplasmin in pigs during the neonatal growth period

The sequence of ceruloplasmin development and limiting factors controlling this process in neonatal piglets was studied in a randomized block design. Guided by the change in serum ceruloplasmin levels, the liver copper concentrations of piglets fed copper-deficient and copper-supplemented diets were compared in three different periods. The plasma of piglets was devoid of both apo- and holo-ceruloplasmin at birth. The system responsible for the synthesis of apoceruloplasmin developed shortly after birth as indicated by a steady increase in serum ceruloplasmin activity during the first week without being affected by the diet. Copper apparently was not the limiting factor at this stage since very high concentrations of copper were found in the livers of newborn piglets. However, the liver copper was depleted quickly within 1 to 2 weeks and became the limiting factor if the diet was deficient in copper. The livers of these piglets were fractionated by differential centrifugation to compare the liver copper distribution in the two dietary groups with and without copper supplementation. The treatments did not affect the copper distribution on a percentage of total liver copper basis. However, fractionation study revealed that, unlike adult pig livers, about 70% to 80% of copper was present in the heavier particle fractions of piglet livers.     

Tissue-specific mRNA expression of a calcitonin receptor-like receptor during fetal and postnatal development

The distribution of calcitonin receptor-like receptor (CRLR) mRNA in developing rats was investigated by in situ hybridization. Signals were found in the piriform cortex, the central and basolateral amygdala and the amygdalostriatal transition area. Among peripheral organs, the CRLR was predominantly expressed in the lung. mRNA expression in blood vessels, liver, midgut, rectum and urethra was restricted to gestational days 16 and/or 20. The CRLR was thought to be a calcitonin gene-related peptide (CGRP) type 1 receptor (Aiyar et al., J. Biol. Chem., 271 (1996) 11325-11329). This contrasts with previously reported evidence that the CRLR is an orphan receptor with no identifiable interactions with CGRP and other related ligands (Flühmann et al., Biochem. Biophys. Res. Commun., 206 (1995) 341-347). In situ hybridization signals have not been detected in the cerebellum and the spleen known to present a high density of CGRP binding sites. The different regional distribution of CGRP receptor binding sites and CRLR mRNA implies the latter encoding a different CGRP receptor subtype.     

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.     

Changes in myocardial A1 adenosine receptor and message levels during fetal development and postnatal maturation

Dysembryoplastic neuroepithelial tumor (DNT) is a recently described rare brain neoplasm with characteristic clinical and morphological features and favorable prognosis. We report here two cases of DNT. The first concerned a 12 years old girl who presented complex seizures preceded by acoustic aura (melodies). Computed tomography revealed a hypodense tumor measuring 2 x 2.5 cm in diameter, located paracortically in the left temporal lobe. The second tumor was removed from a 21-year-old man with partial complex seizures. Nine years earlier patient underwent neurosurgery with partial removal of the tumor The tumor's histopathologic diagnosis is unfortunately lacking. Computed and magnetic resonance imaging showed a mass occupying the cortex and paracortical areas of the anterior pole of the temporal lobe. Histologically, both tumors consisted of small, S-100 protein immunopositive oligodendrocyte-like cells (OLCs) arranged between synaptophysin- and, to a lesser degree, NFP-immunopositive axons (glioneuronal element). In the second case, an area of pilocytic astrocytoma-like appearance was also found, these cells were immunopositive for GFAP. The present study provides clinical, radiological and histological data, which may be helpful in differential diagnosis of this newly recognised brain tumor.     

Effects of cocaine on fetal and postnatal development in mice

The goal of the current investigation was to study the effect of in utero exposure of cocaine on fetal and postnatal development. 48 adult female NIH Swiss mice were used as experimental animal models. Each of the 24 mice were injected intraperitoneally with cocaine HCl at a daily dose level of 45 mg/kg (body weight). Each of the 24 control animals were daily injected with saline. One week after the treatment started, one male was introduced into each female cage. The day the vaginal plug was found was recorded as day one of pregnancy. Both cocaine treated and saline treated animals were subdivided into three subgroups each with 8 animals in each subgroup. Subgroup one was used to obtain midgestational (11 day) fetuses, subgroup two was used to obtain full term fetuses (18 day) and subgroup three was used to obtain pups. Individual fetal weights were taken and each fetus was examined for developmental anomalies. Midgestational fetuses exposed to cocaine had lower body weights than those of the controls. The full term fetuses, however, had similar weight in both experimental and control groups. The pups were weighed every 2 days from day 2 to day 16. The pups showed a slightly wider range of weights in the cocaine treated group as they matured to 16 days. All fetuses and pups revealed no soft tissue anomaly which, along with the weight data, supported our earlier findings.     

Beta-cell mass and proliferation following late fetal and early postnatal malnutrition in the rat

We have recently shown that maternal food restriction during late pregnancy in rats decreased beta-cell mass in the offspring at birth, without altering beta-cell proliferation. The aim of the present work was to determine: 1) whether sustained maternal undernutrition until weaning (R group) more dramatically alters beta-cell mass in the offspring and if normal food supply from weaning until adulthood could reverse the deleterious effects and; 2) if altered beta-cell proliferation was responsible for the decreased beta-cell mass. Beta-cell fraction and proliferative capacity were determined during the suckling period and at adult age after ad libitum feeding from weaning in the R animals and in age-matched controls (C group). At day 21, the offspring born and nursed by food-restricted mothers (R animals) showed a 66% reduction in beta-cell mass and number, which did not increase from birth to weaning, although beta-cell proliferation remained normal. At 3 months of age, R animals had 35% decreased beta-cell fraction, with a 50% decrease in the head of the pancreas. In that area, beta-cell proliferation was similar to that of the controls. In the tail of the pancreas, beta-cell fraction was only slightly impaired but beta-cell proliferation was increased by 37%, as compared with the controls. This increase was associated with a shift in islet size distribution towards medium and large islets compared with the head of pancreas from these R animals. No regional variations of beta-cell fraction, proliferation or islet size distribution were observed in adult control animals. In conclusion, prolonged malnutrition until weaning impairs beta-cell development but not beta-cell proliferation. Subsequent re-nutrition is followed by increased beta-cell proliferation but this is insufficient to fully restore beta-cell mass.     

Effects of cocaine administration during early organogenesis on prenatal development and postnatal growth in mice

Cocaine use has been associated with adverse developmental effects in humans. However, clinical reports both confirm and deny an association between cocaine use and malformations. Similarly, differences in species and strain, as well as route and timing of cocaine administration, have added to the difficulties in determining the teratogenicity of cocaine in animal models. This study was undertaken to compare the effects of dose, route, and timing of cocaine administration in ICR mice during early organogenesis. A single intraperitoneal (ip) administration of cocaine ( > or = 60 mg/kg) on Day 9 of gestation (plug day = 1) produced maternal lethality. The predominant developmental effect of cocaine administration was an increase in the percentage of litters exhibiting an enlarged renal pelvis. Despite a high incidence of affected pups at these doses, the enlargement was not severe. These results, in agreement with previous reports, provide further evidence that the developing urogenital system is sensitive to cocaine administration. When cocaine was administered using a subcutaneous route, pup weights were greater and the incidence of enlarged renal pelvis was lower than when an ip route was used. To better mimic human binge cocaine abuse, the toxicity of a "split dose" was determined. A 60 mg/kg dose was administered using one administration of 60 mg/kg, two treatments of 30 mg/kg, or three administrations of 20 mg/kg with 1 hr separating the treatments. The incidence of enlarged renal pelvis was similar when cocaine was administered as one or two but was decreased when cocaine was administered as three treatments. Both the route and split-dose studies suggest that high-peak serum concentrations are required to perturb development. There were no differences in the incidence or severity of enlarged renal pelvis when cocaine was administered on Day 8, 9, or 10 or on all 3 days of gestation. This suggested that the increase in enlarged renal pelvis may not be a specific teratogenic effect of cocaine administration but may be a delay of normal development induced by cocaine exposure during this early period of organogenesis. To address this hypothesis, cocaine was administered on Day 9 using an ip route and the pups were allowed to be naturally born. In pups whose mothers received cocaine there was an increase in postnatal deaths and a trend toward a reduction in pup body weight/litter at Postnatal Day 21. However, when renal morphology was assessed on Postnatal Day 21 no abnormal kidneys were seen. This supports the hypothesis that enlarged renal pelvis produced by cocaine administration during early organogenesis represents a developmental delay and not a persistent teratogenic defect. These studies suggest that high peak cocaine concentrations are required to delay normal kidney morphogenesis in mice.     

Effects of the level of asphyxia during delivery on viability at birth and early postnatal vitality of newborn pigs

Newborn pigs (n = 117) were used to provide information on the relationships of degree of asphyxia during delivery, viability at birth, and some striking aspects of postnatal vitality including survival, interval between birth and first udder contact and between birth and first suckling, rectal temperature at 24 h of life (RT24), and growth rate over the first 10 d of life. The degree of asphyxia at birth was estimated from cord blood pCO2, pH, and lactate levels. Onset of respiration, heart rate, skin color, and attempts to stand during the first minute after birth were used to estimate the viability score. Neonatal asphyxia, i.e., decreased blood pH and increased blood pCO2 and lactate, was associated with the production of unusually high levels of catecholamines. The degree of asphyxia increased with late position in the birth order (P < .01) and was higher in piglets born posteriorly (P < 0.5). Further, the average blood pCO2 within a litter increased (P < .05) with litter size. The was an inverse relationship between the degree of asphyxia and the viability score (P < .001). Highly viable piglets reached the udder more rapidly (P < .001) and had a higher RT24 (P < .001) than those of low viability. Plasma glucose concentrations increased with blood pCO2 and plasma epinephrine concentrations (P < .001). Neonatal asphyxia reduced postnatal vitality by delaying the first contact with the udder (P < .03) and was associated with a lower RT24 (P < .05), growth rate (P < .001), and survival over 10 d (P < 0.06). These variables, i.e., interval between birth and first udder contact, RT24, and growth rate, were correlated with birth weight (P < .001); RT24 was also shown to decrease (P < .001) with the time taken to reach the udder. Overall, results suggest that piglet suffering from asphyxia during delivery are less viable at birth and less prone to adapt to extrauterine life.     

Comparative investigations on water-soluble crystallins of the embryonic, fetal, and postnatal human lens during development and ageing

To compare the crystallin composition of embryonic and fetal human lenses with those of postnatal and adult lenses, we investigated the crystallins of lenses of various ages (from the 5th gestational week to 55 years) by gel chromatography, isoelectric focusing, immunodiffusion, and immunoelectrophoresis. Age-related changes were calculated as relative percentages of the different classes and subclasses of crystallins. During prenatal lens development the percentages of both high- and low-molecular-weight alpha-crystallins as well as gamma-crystallins gradually increased, whereas the percentage of beta-crystallins decreased. A considerable change in crystallin composition was found immediately after birth: the relative percentage of beta-crystallins increased, whereas that of gamma-crystallins decreased. Gel-filtration analysis of crystallins from juvenile and adult lenses showed a high-molecular-weight peak, which was not found in extracts from fetal and new-born lenses.     

Analysis of testicular migration during the fetal period in humans

PURPOSE: We present an analysis concerning the testicular migration and its position correlated to body weight, crown-rump length and gestational age during the fetal period in humans without congenital abnormalities. MATERIALS AND METHODS: We studied bilaterally 142 testes taken from 71 fresh human fetuses between 10 and 35 weeks after conception. The fetuses were also evaluated in regard to crown-rump length and body weight. The position of the testes was correlated to the fetal parameters. RESULTS: In 37 fetuses (74 testes) at 10 to 23 weeks after conception only 7 testes (9.45%) had migrated from the abdomen and were situated in the inguinal canal, in 19 fetuses (38 testes) at 24 to 26 weeks after conception 22 testes (57.9%) had migrated from the abdomen and in 9 fetuses (18 testes) at 27 to 29 weeks after conception only 3 testes (16.7%) had not descended to the scrotum. The testes had not descended into the scrotum in any fetus weighing 990 gm. or less and with a crown-rump length of 24.5 cm. or less. On the other hand, in all fetuses weighing more than 1,220 gm. and with a crown-rump length of more than 27.5 cm. the testis was in the scrotum. CONCLUSIONS: Until 23 weeks after conception the majority of testes remain in the abdomen. The more intense migration of the testes through the inguinal canal occurred between 21 and 25 weeks after conception. After 30 weeks after conception all testes were descended to the scrotum in all fetuses.     

Neurobehavioral development of neonatal mice following blockade of VIP during the early embryonic period

Previous work has shown that blockade of VIP function in the early postimplantation embryo results in growth retardation and microcephaly. In the present work, the neurobehavioral development of neonatal mice was examined following treatment of dams with a VIP antagonist during this period. Inhibition of VIP functions during early embryogenesis impaired the performance of 5 of 10 developmental behaviors. These behaviors included developmental milestones (first appearance of ear twitch and eye opening) and complex motor behaviors (negative geotaxis, surface righting, and air righting). The retardation of neurobehavioral development produced by inhibition of VIP action indicates that this peptide is important to the progression of embryonic development.     

Muscarinic receptor subtypes in the porcine lung during postnatal development

The responsiveness of the pulmonary circulation to acetylcholine changes in the newborn piglet. Therefore muscarinic receptors have been studied in the developing porcine lung from birth to adulthood using ligand binding, Northern blotting and in situ hybridisation. Maximal binding capacity of [N-methyl-3H] scopolamine and the affinity of the receptor in lung membranes increased between birth and 16 days (p < 0.05). Subtype affinity changed with age, but always M3, > M1 > M2. Northern blots of porcine muscarinic receptor subtypes showed m1, m2 and m3 mRNA present in lung membranes. m2 mRNA was present at all ages and decreased with age. m1 mRNA was absent at birth and m3 mRNA was absent at 3 days. Autoradiographic localisation showed ligand binding to the parenchyma and airway smooth muscle and nerves, there was no binding to intrapulmonary vessels. In situ hybridisation localised mRNA of all three subtypes to the smooth muscle cells of both vessels and airways. Changes in the receptor subtypes may explain the pharmacological changes during postnatal adaptation.     

Polyunsaturated fatty acids in serum lipids of reindeer during the close postnatal period

We examined serum fatty acid composition in reindeer during the close postnatal period (from < 8 h to 3 weeks) by using maternal serum as a reference point and focusing on the proportions of polyunsaturated fatty acids (PUFAs) in serum lipids. A striking dissimilarity was found in the serum PUFAs between the neonatals and their mothers. In particular, the proportions of linoleic acid (18:2) and alpha-linolenic acid in serum cholesteryl esters and phospholipids of the newborn reindeer were significantly lower than those of the mothers. Furthermore, serum phospholipids of the newborns had lower arachidonic acid and docosapentaenoic acid but higher docosahexaenoic acid proportions than the maternal phospholipids. Although the proportions of the principal C18 PUFAs were low in reindeer milk, they increased sharply in serum cholesteryl esters and phospholipids of the calves during the first few days after birth. In particular, there were significant positive correlations in the proportions of 18:2 between serum and milk lipids. We conclude that the proportions of the serum C18 PUFAs are low in the newborn reindeer, but they are increased during the close perinatal period by a rate which suggests an efficient mechanism for selective retention of these fatty acids from milk lipids.