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Biomedical subjects

M Stahlman

Publications and source records attributed to M Stahlman.

At least 19 recordsLinked to original sources
PubMed1992

Distinct effects of oxygen on surfactant protein B expression in bronchiolar and alveolar epithelium.

Hyperoxia causes severe lung injury in association with altered expression of surfactant proteins and lipids. To test whether oxygen induces surfactant protein B (SP-B) expression in specific respiratory epithelial cells, adult B6C3F1 and FVB/N mice were exposed to room air or 95% oxygen for 1-5 days. Northern blot analysis demonstrated an 8- to 10-fold increase in SP-B mRNA after 3 days that was maintained thereafter. In situ hybridization localized SP-B mRNA to bronchial, bronchiolar, and alveolar epithelial cells. Hyperoxia was associated with increased SP-B mRNA, noted primarily in the bronchiolar epithelium and decreased SP-B mRNA in the alveolar epithelium. After 5 days, central regions of lung parenchyma were nearly devoid of SP-B mRNA, while SP-B mRNA was maintained in alveolar cell populations close to vascular structures. To determine whether increased bronchiolar expression of SP-B mRNA during hyperoxia was a specific response, the abundance of CC10 mRNA (a Clara cell protein) was assessed. CC10 mRNA was detected in tracheal, bronchial, and bronchiolar, but not alveolar epithelium and was decreased upon exposure to hyperoxia. Immunocytochemistry demonstrated that SP-B proprotein was detected in bronchial, bronchiolar, and alveolar epithelial cells with staining increased in the bronchial and bronchiolar epithelium upon exposure to hyperoxia. SP-B gene expression in the respiratory epithelium is regulated at a pretranslational level and occurs in a cell specific manner during hyperoxic injury in the mouse.

Animals↗
PubMed1989

Prematurity is associated with abnormal airway function in childhood.

To evaluate the long-term effect of prematurity and/or hyaline membrane disease (HMD) on pulmonary function and airway reactivity, we studied 49 prematurely born children aged 10 to 13 years. They were divided into three groups according to birth weight and HMD status: Groups I and II comprised the children weighing less than 1,500 g at birth, and Group III those whose birth weight exceeded 1,500 g. Children without HMD at birth were classified as Group I and those with HMD as Group II or III. We performed both pulmonary function tests and methacholine (MCh) challenges and compared the results with those of 27 age-matched controls born at term. We found that FEV1 and RV/TLC ratios were significantly different from control values in the groups with birth weights less than 1,500 g, regardless of their HMD status (Groups I and II). In Group I, results for FEF25-75%, Vmax50%, and DLCO were lower than those of controls. Airway reactivity was significantly increased in Groups I and II. A 20% drop in FEV1 after MCh challenge was found in 88%, 62%, 53%, and 36% of children in Groups I, II, and III and controls, respectively, and a 35% drop in SGaw occurred in 87%, 88%, 53%, and 59%. We conclude that prematurity and not HMD per se leads to long-term pulmonary abnormalities and to an increase in nonspecific airway reactivity.

Adolescent↗
PubMed1983

Serial sonographic monitoring of intracranial hemorrhage (ICH) and its sequelae in the preterm neonate.

This study documents changes in ventricular size and brain parenchyma that occurred in 41 preterm neonates that had intracranial hemorrhage, out of 136 preterm neonates that were serially examined. Serial real-time sonographic examinations disclosed a close relationship between the severity of ICH and the development of progressive ventricular dilatation. Eighty percent of preterm neonates with minor degrees of ICH [localized subependymal hemorrhage (SEH) or SEH with small intraventricular hemorrhage (SEH/IVH)] did not develop significant ventricular dilatation, whereas all of the neonates with IVH and/or intraparenchymal hemorrhage (IPH) developed moderate or severe ventricular dilatation. Spontaneous resolution of moderate and/or severe ventricular dilatation did occur by the end of the third week of life in approximately one third of neonates with ICH. The therapeutic implications of the findings are discussed.

Birth Weight↗
PubMed1982

Role of hyaline membrane disease in production of later childhood lung abnormalities.

Between 1961 and 1970, 177 survivors of hyaline membrane disease have been followed clinically and roentgenologically for a minimum of three years to determine the long-term pulmonary outcome. Of these, 153 have been seen for at least six years and 61, for 11 years or more. A total of 175 batteries of pulmonary function tests have been performed on 129 children at age 7 and/or 11 years, Final roentgenograms showed fibrosis in 12 instances, and these changes were positively correlated with the severity of the initial disease, the use of a positive pressure respirator (but not negative pressure respirator), time on the respirator, and length of time in O2, but not high O2 concentrations. Residual symptoms in the first years of life were also correlated with positive pressure respirator use, length of use, and with secondary infection. Pulmonary function tests showed minimal abnormalities in 12 children when last seen. None of these children had a history of exercise intolerance or chronic respiratory symptoms. The ultimate pulmonary history of this population of patients is unknown, but overt childhood lung disease following hyaline membrane disease is not a frequent occurrence.

Child↗
PubMed1977

Red cell volume measurements and acute blood loss in high-risk newborn infants.

Red cell volume was measured in 259 infants admitted to a high-risk newborn unit. Red cell volume was measured using 50Cr tagging which subsequently was activated to 51Cr for counting. Total blood volume was calculated using the corrected whole body hematocrit. A low red cell volume was frequently associated with a maternal history of vaginal spotting, with placenta previa or placenta abruptio, with nonelective cesarean section, and with deliveries associated with cord compression. Asphyxiated infants without a history suggestive of blood loos often had a low red cell volume. An early central hematocrit below 45% correlated with a low red cell volume, but a normal or high hematocrit was often associated with low red cell measurements. The total blood volume depended largely on whether the tagging was done long enough after the blood loss for plasma volume equilibration to have occurred. Very low red cell volume values were associated with a high mortality rate, but birth weight played a dominant role in survival, even at low red cell volume levels.

Asphyxia Neonatorum↗
PubMed1977

PaO2 levels and retrolental fibroplasia: a report of the cooperative study.

The relation between PaO2 and retrolental fibroplasia (RLF) was studied prospectively in 719 premature infants born in or treated in the intensive care units of a group of university hospitals. Blood gas studies were performed on 589 of these infants, 66 of whom had a diagnosis of RLF; in 27 of these 66, some grade of mostly nonblinding cicatricial disease developed. The frequency of RLF was highest among infants of lowest birth weight. A multivariate statistical method was used to analyze simultaneously the effect of possible etiologic factors associated with RLF. The occurrence of RLF was found to be unrelated to PaO2, as determined by the limited information available from intermittent sampling. RLF is associated with concentration of oxygen administered in the lightest birth weight group, but the strongest association, aside from birth weight, was with time in oxygen. None of the other variables involving blood chemical values appeared to be associated with RLF. The severity of cicatricial RLF is clearly greater in infants weighing less than 1,200 g at birth. Conservative administration of oxygen may have been responsible for failure to demonstrate quantitative association between PaO2 levels and disease. Agreement between the observed and predicted numbers of infants with RLF demonstrate the strength of the multivariate technique employed in making the statistical analyses.

Birth Weight↗
PubMed1975

Delayed radiographic presentation of congenital right diaphragmatic hernia.

The diagnosis of right-sided Bochdalek hernias is diffucult. Problems encountered in diagnosis include delayed radiographic manifestations and stimulation of inflammatory disease. The case is presented of a neonate in whom a right-sided diaphragmatic hernia masqueraded as inflammatory disease of the chest.

Diagnosis, Differential↗