Respiratory syncytial virus infection enhances the response to laryngeal chemostimulation and inhibits arousal from sleep in young lambs

To evaluate the effect of respiratory syncytial virus (RSV) infection on the response to laryngeal chemostimulation (LCS) with water, five lambs were inoculated with human RSV and three lambs were given control media at an age of 3-5 days. During RSV infection, LCS resulted in increased inhibition of minute ventilation and delayed recovery of regular breathing. Sleep further increased the response, and arousal was less likely to occur in active sleep. Two of the five infected lambs needed resuscitation after LCS when arousal was absent. Histological studies showed bronchiolitis and pneumonitis. Laryngeal tastebud morphology was unchanged at 8 days after inoculation. However, infected lambs had disrupted tastebuds 4-6 weeks after infection. Failure to arouse and to terminate reflex apnea may play a role in the pathogenesis of the sudden infant death syndrome associated with respiratory tract infection.

Temporal-spatial distribution of SP-B and SP-C proteins and mRNAs in developing respiratory epithelium of human lung

We determined the temporal and spatial distribution of surfactant protein B (pro-SP-B) and C (pro-SP-C) mRNAs and proteins by immunohistochemistry and in situ hybridization in fetal, neonatal, and adult human lung. Pro-SP-B and SP-B mRNA were detected in bronchi and bronchioles by 15 weeks' gestation. After 25 weeks, pro-SP-B, active SP-B peptide, and SP-B mRNA were co-localized in bronchiolo-alveolar portal cells and in Type II epithelial cells. In adult lung, pro-SP-B and SP-B mRNA were detected primarily in non-ciliated bronchiolar epithelial cells and in Type II cells in the alveolus. Pro-SP-C and SP-C mRNA were detected in cells lining terminal airways from 15 weeks' gestation and thereafter. After 25 weeks, SP-C mRNA and precursor protein were detected in epithelial cells of the bronchiolo-alveolar portals and in Type II cells, where expression increased with advancing gestational age. Distinct cellular patterns of staining for pro-SP-B compared with SP-B active peptide support the concept that its proteolytic processing or cellular routing may be influenced by cell type and/or cell differentiation. SP-B and SP-C are expressed primarily in distal conducting and terminal airway epithelium of human fetal lung well in advance of surfactant lipid synthesis or physiologic requirements to produce pulmonary surfactant at the time of birth.

Developmental expression of SP-A and SP-A mRNA in the proximal and distal respiratory epithelium in the human fetus and newborn

We used immunolocalization and in situ hybridization to determine the distribution of SP-A and SP-A mRNA in lungs of human fetuses and normal newborn infants. Early in the second fetal trimester a few immunostained cells were observed in tracheal epithelium, often in mucosal folds near the origin of submucosal gland ducts. Non-mucous tracheal gland cells were immunostained for SP-A as they became differentiated. Expression of SP-A mRNA was similar to that of immunolocalization in the second trimester. Immunostained cells and SP-A mRNA also appeared about the same time in gestation in isolated cells of bronchial epithelium and glands. SP-A mRNA was seen in bronchiolar cells and pre-Type II cells lining terminal airways of fetuses at 19-20 weeks of gestation. Only in liveborn infants did cells of bronchioloalveolar portals and mature Type II cells contain SP-A mRNA or immunostain for SP-A. In postnatal infants, luminal material was also stained for SP-A. Although some alveolar macrophages contained immunoreactive material, SP-A mRNA was never detected. The abundance of SP-A in tracheal and bronchial glands and epithelium of conducting airways supports the importance of non-surfactant-associated functions for SP-A and may be related to a role in host defense.

Colocalization of peptide hormones in neuroendocrine cells of human fetal and newborn lungs: an electron microscopic study

This study investigated the colocalization of the peptide hormones bombesin or calcitonin with calcitonin gene related peptide (CGRP) in neuroendocrine cells (NE) in the lungs of human fetuses of varying gestational ages and in the lungs of newborn infants who died with acute or chronic lung disease in the first weeks or months after birth. Double immunolabeling of dense core granules for these peptides was also studied in this same patient population. On-grid double gold immunolabeling was carried out on 29 subjects using anti-bombesin and anti-CGRP and on 22 subjects using anti-calcitonin and anti-CGRP as primary antibodies, the secondary antibodies being labeled with different-size gold spheres. Colocalization of both bombesin and calcitonin with CGRP was demonstrated, not only in the same NE cell, but also on the same dense core granule. Colocalization was rarely found in normal fetuses, and most frequently found in newborn infants with acute lung disease, usually hyaline membrane disease (HMD), or with the development of chronic lung disease in the first weeks or months after birth. Double labeling of the same dense core granules might imply action of peptides in concert, or perhaps one peptide acting in a paracrine role (e.g., on bronchial or bronchiolar smooth muscle) and the second peptide acting in an autocrine fashion on the parent cell (e.g., in the regulation of granule production or release).

The ontogeny and distribution of surfactant protein B in human fetuses and newborns

The distribution of immunoreactive surfactant-associated protein B (IR-SP-B) was studied immunohistochemically in 120 subjects from 10 weeks of gestation to 7 postnatal months with a polyclonal antibody against human SP-B. Electron microscopy (EM) was done in 72 subjects to document the presence of Type II cells containing lamellar bodies. Fetuses of less than 18 weeks' gestation showed no immunostaining. Beginning at 18 weeks, non-mucous cells of tracheal glands immunostained in a few instances. Fetuses of 19 through 23 weeks showed progressive immunostaining of cells lining terminal airways. Infants 26-40 weeks who died with or without pulmonary pathology showed immunostaining of Type II cells and bronchioloalveolar (BA) portal cells of the respiratory bronchioles. In infants with hyaline membrane disease (HMD) who died less than 12 days after birth, occasional tracheal gland cells, BA portal cells, and mature and relining Type II cells immunostained. In bronchopulmonary dysplasia (BPD), BA portal cells, relining Type II cells, macrophages, and luminal material immunostained. Occasional tracheal and bronchial gland cells and Clara cells immunostained. The appearance of IR-SP-B at mid-gestation correlated with differentiation of Type II cells. There was good correlation of immunostaining with the presence of lamellar bodies on EM. Accelerated maturation of the lung was often associated with premature rupture of membranes (PROM).

Human surfactant protein-A contains blood group A antigenic determinants

A major blood group antigenic epitope was identified on human pulmonary surfactant protein A (SP-A). MAb and polyclonal antibodies generated against purified human SP-A aggregated blood group A human erythrocytes and immunostained epithelial cells in a variety of human tissues, consistent with the tissue distribution of major blood group antigens. SP-A MAb (MAb-8) agglutinated red cells and immunostained tissues from A or AB blood groups, but did not react with cells or tissues from O or B individuals. MAb-8 immunostaining of tissue from blood group A individuals was ablated by incubation with blood group A red cells. MAb and polyclonal antibodies directed against A blood group antigens reacted strongly with purified SP-A obtained from a blood group A individual with alveolar proteinosis. MAb and polyclonal antibodies specific for B blood group antigen failed to react with SP-A from this patient or from patients who were in blood group B. Reactivity of anti-blood group MAb was lost after treatment of SP-A with endoglycosidase-F, demonstrating its reactivity with an epitope dependent on the asparagine-linked oligosaccharide at asparagine 187. Reactivity of MAb-8 with SP-A persisted after endoglycosidase-F treatment, but was lost after digestion with collagenase as assessed by Western blot after SDS-PAGE. Reactivity of MAb to SP-A was sensitive to beta-elimination, supporting the presence of another blood group antigenic site distinct from the epitope dependent on the asparagine-linked carbohydrate. The finding that the SP-A molecule contains a major blood group epitope has implication for the clinical use of surfactant replacement preparations and diagnostic reagents based on this protein.

Lipocortin-1 immunoreactivity in the human pituitary gland

We evaluated the distribution of lipocortin-1 immunoreactivity in 118 immature or mature human hypophyses using the peroxidase-antiperoxidase (PAP) technique with a polyclonal rabbit antiserum against lipocortin-1. Serial sections were evaluated for five pituitary hormones and S-100 protein immunoreactivity to compare their distributions with that of lipocortin-1. Scattered or moderate numbers of cells exhibited lipocortin-1 immunoreactivity in the pars distalis of 89 subjects ranging in age from 27 weeks' gestation to 83 years. Seven immature and seven aged specimens exhibited no immunostaining, while 15 specimens from older individuals exhibited only rare immunostaining. Immunostaining did not appear to co-localize selectively with any specific pituitary hormone, although the distribution of immunoreactivity did overlap that of some corticotrophs and was seen in elongated processes of S-100-containing folliculostellate cells. Lipocortin-1 was also found in epithelial cells lining colloid cysts of the residual pars intermedia in 115 of 118 pituitaries ranging in age from 23 weeks' gestation to 83 years. In many intermediate lobe cysts, lipocortin-1 exhibited a pattern of immunoreactivity that partially overlapped the distribution of S-100 protein immunostaining, although the pattern was not identical. Pre-absorption of anti-lipocortin-1 antiserum with lipocortin-1-coupled Sepharose-4B immunoreactivity resulted in loss of immunoreactivity in both lobes. No lipocortin-1 immunoreactivity was seen in the neurohypophysis.

Factors related to practice of breast self-examination in rural women

The purpose of this study was to examine variables related to breast self-examination (BSE) in rural women. The sample of convenience consisted of 347 women who were members of selected county-extension homemaker clubs. Champion's Health Belief Model Scale was used to measure susceptibility, seriousness, benefits, barriers, health motivation, sociodemographics, and knowledge variables and frequency of BSE. Multiple regression analysis indicated that the Health Belief Model concepts accounted for 26% of the variance in BSE practice. Women who perceived more benefits of BSE in reducing the severity of breast cancer were more likely to report more frequent BSE. Women who perceived fewer barriers to performing BSE and those who scored high on health motivation were also more likely to report performing monthly BSE. Pearson product-moment correlation indicated a significant positive relationship between the variables of BSE knowledge and BSE practice (r = 0.1216; p = 0.023). The lambda statistics showed weak or no association between the demographic variables of age, race, marital status, religion, education, personal experience with breast disease, and friend's experience with breast disease and BSE practice. These findings suggest that perhaps educational programs emphasizing benefits of BSE may be implemented for women represented in this sample in an attempt to increase the number of women practicing BSE. Assessment of women's perceptions of potential barriers would allow nurses to plan appropriate strategies that could reduce the barriers. Finally, assessment of women's general health practices may identify women motivated toward good health. These women may be likely to complete monthly BSE if encouraged to do so.

Ontogeny of epidermal growth factor receptor and lipocortin-1 in fetal and neonatal human lungs

The ontogeny and distribution of the epidermal growth factor (EGF) receptor and lipocortin-1, a major cellular substrate of the EGF receptor, were evaluated in a developmental series of fetal and neonatal human lungs (8 to 41 weeks' gestation and stillborn to 16 days' postnatal age). The peroxidase anti-peroxidase technique with two polyclonal antibodies recognizing the EGF receptor and one polyclonal antibody recognizing lipocortin-1 were used for immunohistochemical localization. Extensive or scattered bronchiolar EGF receptor immunoreactivity appeared in the entire series of frozen lung specimens from 15 to 32 weeks' gestation. Bronchial glands exhibited EGF receptor immunostaining from 19 weeks onward, and immunoreactivity in bronchial epithelium was detected from 23 weeks onward. Most tracheas showed extensive lipocortin-1 immunoreactivity in the epithelium beginning at 10 weeks' gestation. Immunostaining was also seen in cells lining the ducts of submucosal glands after 15 weeks' gestation and in nonmucous acinar cells of tracheal glands after their appearance at 18 weeks' gestation. Bronchial epithelium exhibited lipocortin-1 immunoreactivity from 12 weeks' gestation onward. Bronchial gland necks became immunostained from 16 weeks' gestation onward, followed by acinar immunostaining as they subsequently developed. Bronchiolar epithelium was immunostained as early as 12 weeks, beginning with the largest airways, and by 24 weeks extending distally to the bronchioloalveolar portals. Lipocortin-1 immunostaining of larger conducting airway epithelium was primarily confined to ciliated cells. Neither EGF receptor nor lipocortin-1 immunoreactivity was detected in alveolar type I or type II cells, fibrocytes, chondrocytes, or smooth muscle cells at any gestational age. These developmental patterns suggest that the EGF receptor and lipocortin-1 may participate in normal growth factor-induced proliferation of the conducting airways and their glands in the human fetal lung and trachea.

Lung vascular permeability changes in lambs with hyaline membrane disease

To investigate the mechanism of pulmonary edema in hyaline membrane disease (HMD), lymph from the efferent duct of the mediastinal lymph node was collected in premature lambs before and after delivery by cesarean section. Mean lymph flow in 7 lambs with histologically verified HMD increased progressively over 4 h after delivery to 3 times the fetal value, while lymph flow in 7 lambs without HMD increased to 3.5 times at 1 h and decreased thereafter. At 4 h after birth, lung lymph flow was significantly higher in lambs with HMD than in lambs without HMD (0.70 +/- 0.15 (SEM) vs 0.43 +/- 0.07 ml.h-1.kg-1). Lymph/plasma concentration ratio for small endogenous protein fractions (effective molecular radius, 3.6 and 3.8 nm) was significantly higher in lambs with HMD than in lambs without HMD at 2-4 h. Postmortem extravascular lung water was significantly higher in lambs with HMD (6.1 +/- 0.5 vs 4.3 +/- 0.3 ml/g dry lung weight). It is concluded that lung water is high in lambs with HMD, which appears to be a result both of delayed absorption of fetal lung liquid and increased permeability of the pulmonary exchange vessels.

Ontogeny of epidermal growth factor receptor/kinase and of lipocortin-1 in the ovine lung

We have examined the ontogeny and distribution of the epidermal growth factor receptor/kinase (EGF receptor) and of lipocortin-1, a major cellular substrate of the EGF receptor, in a developmental series of 13 normal ovine fetal lungs (44-145 d of gestation) using the peroxidase anti-peroxidase technique with two extensively characterized polyclonal antibodies recognizing the EFG receptor and one polyclonal antibody recognizing lipocortin-1. Immunoreactive EGF receptor/kinase and lipocortin-1 were detected in conducting airway epithelium by the end of the first trimester of pregnancy before bronchial glands could be identified. This was followed at two-thirds of gestation by immunoreactivity in bronchial glands and large bronchioles adjacent to positive bronchi. By seven-eighths of gestation conducting airway epithelium no longer contained consistently detectable immunostaining for EGF receptor, although lipocortin-1 was identified until term in all levels of conducting airways. In contrast, neither EGF receptor nor lipocortin-1 immunoreactivity was detected in alveolar type I or type II epithelial cells, fibrocytes, chondrocytes, smooth muscle, or endothelial cells at any gestational age. These findings suggest that EGF receptor and lipocortin-1 may participate in early airway development.

Immunocytochemical localization of epidermal growth factor in the developing human respiratory system and in acute and chronic lung disease in the neonate

Cells staining for immunoreactive human epidermal growth factor were sought in the lungs and tracheas of human fetuses from 8 to 24 weeks of gestation. Lungs of liveborn infants from 25 to 40 weeks of gestation (stillborn to 7 months postnatal life), both with and without lung pathology, were also studied. In the early fetal trachea (12 to 15 weeks), many nonciliated cells immunostained for immunoreactive human epidermal growth factor in the lining epithelium. By 16 weeks of gestation this widespread staining was replaced by stained nonciliated single cells or small clusters of cells which were identifiable until 24 weeks. In the few tracheas which were available from liveborn infants who died without evidence of lung disease, stained cells were seldom identified in the lining epithelium after 24 weeks of gestation. In contrast, from 18 weeks until term, tracheal submucosal glands contained scattered cells which immunostained for immunoreactive human epidermal growth factor but which did not appear to be classical mucous cells. Beginning at 20 weeks of gestation, positively staining cells were found occasionally in bronchial lining epithelium, but more often in bronchial submucosal glands. Immunostained cells were never identified in bronchiolar epithelium in normal fetal or newborn lungs. In liveborn infants from 24 weeks onward who developed lung disease, many tracheas were severely damaged. In the presence of extensive denudation of the mucosa or the development of squamous metaplasia, immunostained cells were rarely seen in the lining epithelium. However, even under these conditions stained glandular cells could usually be identified. Stained cells were also present in the necks of those tracheal glands from which new epithelial lining cells appeared to be migrating onto denuded surfaces. Immunostained cells in the bronchial lining epithelium of infants with chronic lung disease were infrequent, just as they were in the fetus, but bronchial submucosal glands contained positively stained cells similar to those in tracheal glands. The appearance and distribution of immunostained cells were similar in the tracheal and bronchial submucosal glands in both normal subjects and those with all stages of lung disease. In contrast to the bronchioles of fetuses and infants without lung pathology, the bronchiolar epithelium of infants with chronic lung disease contained immunostained cells. Immunostained cells were found in areas of migrating dysplastic cells in relining conducting airways.(ABSTRACT TRUNCATED AT 400 WORDS)

Intestinal lipoprotein synthesis in control and hypercholesterolemic rats

Previous studies in our laboratory have shown that very-low-density lipoproteins (VLDL) synthesized by the intestine of the diet-induced hypercholesterolemic rat are enriched in cholesteryl esters and unesterified cholesterol compared with intestinal VLDL from control rats. In these studies, we isolated and characterized nascent intestinal Golgi intermediate-density lipoproteins (IDL, d 1.006-1.040 g/ml) and studied isotope incorporation into apoliproteins of Golgi VLDL from control and hypercholesterolemic rats. IDL were triacylglycerol-rich lipoproteins but contained more cholesteryl ester and protein than the corresponding Golgi VLDL fractions. IDL from hypercholesterolemic rats were enriched in cholesteryl esters to a greater extent than IDL from control rats. The apolipoprotein patterns of IDL fractions were the same as those of intestinal Golgi VLDL, consisting of apolipoproteins (apo) B-48, A-I and A-IV. Time-course isotope incorporation curves for apo A-I and A-IV in Golgi VLDL were similar, but they differed from curves for apo B-48. None of these curves was markedly altered in the hypercholesterolemic rat. We conclude that the major effect of increased dietary cholesterol on intestinal lipoprotein biosynthesis is to increase the percentage of cholesteryl esters in Golgi lipoproteins. Dietary cholesterol does not alter the apolipoprotein composition of Golgi lipoproteins, nor does it have a significant effect on the pattern of isotope incorporation into apolipoproteins of Golgi VLDL. The effect of cholesteryl ester enrichment on the subsequent metabolism of these particles in the circulation and the effect of these particles on hepatic lipoprotein production remain to be determined.

Effect of retinol on fetal lamb tracheal epithelium, with and without epidermal growth factor. A model for the effect of retinol on the healing lung of human premature infants

Twelve pairs of fetal lambs were used to test the hypothesis that the necrotizing tracheobronchitis followed by squamous metaplasia seen in premature infants who develop chronic bronchopulmonary dysplasia might be related to low retinol stores and might, therefore, be reversed by retinol supplementation. Epidermal growth factor (EGF) was used to model the growth factor stimulus initiated by chronic wounding of the airways, and retinol was used as a differentiator of proliferating cells stimulated by EGF. Saline-treated animals were used as controls, as were fetal lambs receiving retinol alone or EGF alone. The effects of EGF on tracheal and bronchial epithelium consisted of proliferation of basal and intermediate cells, necrosis and slough of lining ciliated and mucous-producing cells, followed by squamous metaplasia. In fetal lambs given retinol, plasma, liver and lung retinol levels rose and mucous producing cells were increased in number. In the presence of EGF plus retinol, differentiation of mucous-producing cells was accelerated. We believe that this fetal lamb model with low initial levels of retinol in plasma, liver and lung, treated with EGF may mimic human premature infants with chronic bronchopulmonary dysplasia, and that the addition of retinol in amounts sufficient to raise their tissue levels produces a more normal surface epithelium in conducting airways.

Calcitonin gene-related peptide in human fetal lung and in neonatal lung disease

The ontogeny of calcitonin gene-related peptide immunoreactivity (CGRP-IR) was evaluated immunohistochemically in 67 human fetal or newborn lungs previously analyzed for calcitonin immunoreactivity (CT-IR). CGRP-IR was present by 10 weeks of gestation in rare, solitary neuroendocrine (NE) cells of developing conducting airways in two of eight first-trimester lungs. During the second trimester, cells with CGRP-IR were found consistently (21/23 fetuses). However, the numbers of positively staining cells did not appear to increase in these fetuses or in third-trimester infants dying of non-pulmonary causes. The highest concentrations of CGRP-IR cells were seen in lungs of premature infants with advancing chronic lung disease associated with bronchopulmonary dysplasia (BPD). CGRP-IR was seen earlier in gestation and in greater numbers of NE cells than was calcitonin immunoreactivity (CT-IR) reported previously in these same fetal lungs (Lab Invest 52:52, 1985). Its presence paralleled that of CT-IR in postnatal chronic lung disease.

Beta-adrenergic receptor properties of a pulmonary alveolar type II cell preparation from the adult rat

The pulmonary alveolar type II cell synthesizes and secretes phosphatidylcholine (PC), a major component of surfactant, above basal level in response to beta-adrenergic stimulation. The investigation of the specific receptor which mediates these events was the topic of this study. Freshly isolated type II cells from adult rats were disrupted in a French pressure cell, and crude particulate fractions were recovered and used in assays for binding of the radioligand (-)-3-[125I]-iodocyanopindolol. The receptor had high affinity for beta-adrenergic agents, and specific binding to the receptor was saturable and reversible. The KD value obtained by kinetic means (19.6 pM) was in close agreement with that obtained by Scatchard (21.5 pM) and Hill (21.3 pM) analyses of steady-state binding data. The Scatchard correlation coefficients and Hill plot coefficients were close to 1, indicative of a single class of binding sites which displays no cooperativity. The specificity for catecholamine agonists and stereoselectivity observed were appropriate for a beta-adrenergic receptor. Use of selective drugs identified the presence of both beta 1- and beta 2-adrenergic receptor subtypes (1:3, respectively) on this cell type.

Ontogeny of neuroendocrine cells in human fetal lung. III. An electron microscopic immunohistochemical study

Immunocytochemistry at the transmission electron microscopic level utilizing colloidal gold spheres conjugated with secondary antisera was performed on lungs of 22 human fetuses and newborn infants of 13 to 38 weeks gestation and from birth to 5 1/2 months of postnatal life. Tissue was stained for the peptide hormones, immunoreactive (IR) bombesin, and IR calcitonin. In addition to unmatched neuroendocrine (NE) cells identified for these peptides, matched cells were identified in near-serial ribbons, each stained for an individual peptide. Based on morphology, five subtypes of NE cells were examined for these two peptides. We have confirmed the previously demonstrated developmental appearances of these peptides in human fetal lung. We also have found many cells containing both peptides in the lungs of live-born infants of 25 weeks gestation or more who survived long enough to develop chronic lung disease. The percentage of neurosecretory granules labeled for IR bombesin which overlapped with the percentage of granules labeled for IR calcitonin in cells of several dysplastic lung suggested that both peptides could be contained within a single granule. This was confirmed in NE cells of four such infants in preliminary studies utilizing double labeling immunocytochemistry at the electron microscopic level. At least two subpopulations of NE cells were not labeled for either peptide, suggesting that as yet-unidentified peptides and/or amines are contained in their granules. The possibility that large nonlabeled granules contain hormone precursors is also raised.

Immunocytochemical localization of human epidermal growth factor/urogastrone in several human tissues

Epidermal growth factor (EGF) stimulates the growth of many tissues and inhibits stimulated gastric acid secretion. Its primary tissue of origin in man is still unknown. We used polyclonal anti-human EGF sera in the peroxidase-antiperoxidase immunocytochemical staining technique to identify immunoreactive human EGF (ihEGF) in tissue sections from 29 subjects ranging from fetuses to 63 years in age. In addition to acinar cells in the submandibular salivary glands and cells of Brunner's duodenal glands, previously reported to contain ihEGF, we found ihEGF in most anterior pituitary glycopeptide hormone-secreting cells, in gastric and pyloric gland cells of the stomach, and in bone marrow cells that resembled mononuclear phagocytes in subjects of all ages. The eccrine sweat glands in the skin of adults also contained ihEGF. Cells containing ihEGF were found singly or in clusters in the trachea of the fetus only. No fetal pancreatic islet cells stained, but occasional cells in neonates and a majority of islet cells in older subjects contained ihEGF; there was no constant association with insulin, glucagon, or somatostatin. Only the lactating breast contained ihEGF. In adults, outer adrenomedullary cells contained ihEGF. Intense immunostaining was observed in the renal medulla, apparently limited to the extracellular area between the renal tubules, and increased with age; the cortex was devoid of ihEGF. No ihEGF was detected in posterior pituitary gland, thyroid gland, heart, lung, or liver at any age. An adult prostate contained ihEGF only in an area of local injury, and some primordial follicles from the ovary of a newborn appeared to contain ihEGF. Thus, many tissues appear to synthesize hEGF, which may exert exocrine, endocrine, or paracrine functions in different tissues and at different ages.

Ontogeny of neuroendocrine cells in human fetal lung. II. An immunohistochemical study

Immunocytochemistry using horseradish peroxidase-antiperoxidase technique was performed on the lungs of 60 human fetuses and newborn infants of 8 to 40 weeks' gestation and from birth to 7 months' postnatal life. Tissue was stained for the peptide hormones, immunoreactive (IR) bombesin, IR calcitonin and IR Leu-enkephalin, as well as for IR serotonin. IR bombesin appeared in neuroendocrine cells and neuroepithelial bodies in the developing conducting airways of fetuses by 10 weeks' gestation and increased in number primarily in bronchioles as gestation progressed. They were most numerous in live-born infants with chronic respirator lung disease. In contrast, IR calcitonin-staining cells did not appear until late in the second trimester. They were present in small numbers from 20 weeks onward but were also most numerous in infants with chronic respirator lung disease. IR serotonin-staining cells were readily found in lungs of fetuses in the first trimester. By the second trimester many solitary neuroendocrine cells and neuroepithelial bodies staining for IR serotonin were present in developing terminal airways and a lesser number appeared in bronchioles and intrapulmonary bronchi. In premature infants, IR serotonin-staining cells were scarce in the presence of acute hyaline membrane disease but were numerous in lungs of infants with regenerating conducting airways associated with chronic respirator lung disease. IR Leu-enkephalin-staining cells were found only in one infant who survived 7 postnatal months of respirator care following neonatal hyaline membrane disease.

Ontogeny of neuroendocrine cells in human fetal lung. I. An electron microscopic study

An electron microscopic study of human fetal lung was undertaken to describe the ontogeny of neuroendocrine (NE) cells and neuroepithelial bodies (NEBs) and to determine their relationships to the developing nervous system. Lungs of 34 fetuses and 22 newborns were examined. Putative NE cells appeared prior to 8 weeks of gestation but, by 10 weeks, differentiated into NE cells and NEBs. Between 13 and 24 weeks the number of NE cells and NEBs increased, and subpopulations of NE cells were identified: a small population of cells that reached from basement membrane to lumen and NE cells associated with an electron-dense epithelial cell. Material past 24 weeks of gestation was obtained from live-born infants who died at various postnatal ages. Much of this material represented acute pulmonary damage in which NE cells were difficult to identify. As chronic lung disease developed, NE cells, singly and in groups, were easily identified in regenerating conducting airways. Growing axons associated with both NE cells and NEBs appeared as early as 10 weeks of gestation. Rare cholinergic, adrenergic, and nonadrenergic-noncholinergic terminals were identified in contact with NE cells and deep within NEBs. Afferent axon terminals were not identified with certainty. The data presented demonstrate innervation to at least some NE cells and NEBs throughout fetal life. It has been proposed that NE cells and NEBs are intrapulmonary neuroreceptors with paracrine secretory function. The present study suggests more complicated mechanisms integrated with the autonomic nervous system, inducing reflex activity at the level of the central nervous system. A tropic role for NE cells in the developing and regenerating lung is proposed.

Intestinal lipoprotein synthesis. Comparison of nascent Golgi lipoproteins from chow-fed and hypercholesterolemic rats

Hypercholesterolemia, induced by a cholesterol-enriched diet, is associated with distinctive modifications in the serum lipoproteins of a variety of species. Present in the serum of these animals are several classes of lipoproteins enriched in cholesteryl esters and apolipoprotein E. To investigate the role of intestinal lipoprotein synthesis in diet-induced hypercholesterolemia, we characterized nascent lipoproteins retrieved from Golgi apparatus-rich fractions of intestinal epithelial cells from chow-fed control and hypercholesterolemic rats. To eliminate chylomicrons from the preparations, rats were fasted overnight prior to the experiments. Golgi very low density lipoproteins (d less than 1.006 g/ml) from control rats were triglyceride-rich lipoproteins that migrated slightly slower than pre-beta migrating serum very low density lipoproteins. These particles contained apoproteins B-240, A-IV, and A-I. Golgi very low density lipoproteins from hypercholesterolemic rats were likewise triglyceride-rich lipoproteins migrating electrophoretically like control Golgi very low density lipoproteins and they contained apoproteins B-240, A-IV, and A-I. However, these latter particles contained less triglyceride and more cholesterol compared to control Golgi very low density lipoproteins. In addition, by radioisotope incorporation studies, Golgi very low density lipoproteins from hypercholesterolemic rats contained relatively more apoprotein A-IV (21.6 vs. 11.0%) and less apoprotein B-240 (17.0 vs. 27.0%) than found in control Golgi very low density lipoproteins. Approximately 60% of the total apoprotein radioactivity was found in apoprotein A-I in both preparations. We conclude that intestinal lipoprotein synthesis is modified by diet-induced hypercholesterolemia. The significance of these modifications with respect to the marked hypercholesterolemia observed in these animals remains to be determined.

Pulmonary hemodynamic and ultrastructural changes associated with Group B streptococcal toxemia in adult sheep and newborn lambs

A toxin isolated from Group B beta-hemolytic streptococci, Type III was infused into adult sheep and newborn lambs. A two-phased reaction was observed. There was an initial phase of pulmonary hypertension and high flow of protein-poor lymph. This was followed by a second phase when pressures returned to baseline but lymph flow remained twice the baseline values and protein concentration in lymph increased. During the second phase there was a significant increase in lymph protein clearance, suggestive of increased microvascular permeability to protein. The absolute granulocyte count decreased to 10% of baseline values by 60 min after the infusion, and was followed by a variable return to baseline. The sheep with the largest changes in protein clearance were those who had the slowest return to baseline values. Pathologic examination of lung tissue revealed there was capillary dilation, interstitial edema, and large numbers of granulocytes in the lungs. The basement membranes of both capillaries and arterioles showed disruption and widening, along with fragmentation of the internal elastic membrane. This study provides morphologic and physiologic evidence of increased pulmonary vascular permeability after injection of streptococcal toxin associated with granulocyte trapping in the lung. We postulate that granulocytes may be involved as mediators of the pulmonary vascular injury.

The effect of pangamic acid on maximal treadmill performance

The effect of pangamic acid (calcium gluconate and N, N-Dimethylglycine) ingestion was examined during short-term maximal treadmill performance on 16 male track athletes. The study was conducted as a double-blind experiment with an experimental group (E) whose members each ingested six 50-mg pangamic acid tablets per day and a control group (C) whose members each ingested six placebo tablets per day for three weeks. The placebo tablets were identical to the pangamic acid tablets in appearance. Subjects were tested by using the Bruce treadmill protocol before and after treatment. The following parameters were examined: maximal heart rate (HR), treadmill time (TM), recovery HR at minutes 1 and 3, and pre-test and post-test blood glucose and lactate levels. Pre-treatment data were 183 bpm (E) and 194 bpm (C) for maximal HR, 16.99 min (E) and 16.49 min (C) for TM, 132.13 mg% (E) and 133.38 mg% (C) for post-test glucose, and 64.63 mg% (E) and 76.13 mg% (C) for post-test lactate. Post-treatment data were 181 bpm (E) and 194 bpm (C) for maximal HR, 17.21 min (E) and 16.83 min (C) for TM, 138.88 mg% (E) and 139.13 mg% (C) for post-test glucose, and 70.88 mg% (E) and 66.58 mg% (C) for post-test lactate. Multivariate analysis of variance (MANOVA) revealed no significant differences (P greater than 0.05) between groups after treatment. It was concluded that ingestion of pangamic acid does not produce significant changes in short-term maximal treadmill performance.