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Biomedical subjects

J M Snyder

Publications and source records attributed to J M Snyder.

At least 73 records · Page 4Linked to original sources
PubMed1983

Regional anesthesia during newborn circumcision. Effect on infant pain response.

A controlled, double-blind investigation was undertaken to determine whether regional anesthesia by dorsal penile nerve block (DPNB) could effectively minimize the pain and behavioral disruptions usually associated with newborn circumcision. Fifteen infants had DPNB with lidocaine, eight control infants had DPNB with saline, and eight additional control infants were circumcised without undergoing DPNB. Newborn distress was gauged by subjective observation, measurement of heart rate, and the percent of time spent crying in six sequential timed intervals during circumcision. Ninety-three percent of subjects who received lidocaine were observed to have a decrease in agitation after anesthetic administration. The mean increase in heart rate during circumcision was at least 50 percent less in the lidocaine injected group than in either control group (p less than 0.01). Infants who had DPNB with lidocaine cried 50 percent less during circumcision compared to combined controls (p less than 0.01). DPNB was easily administered, and there were no significant complications. Physicians who circumcise newborns have good reason to employ the technique of dorsal penile nerve block with lidocaine to minimize infant pain and distress.

Anesthesia, Local↗
PubMed1983

Hormonal regulation of the synthesis of lamellar body phosphatidylglycerol and phosphatidylinositol in fetal lung tissue.

The influence of hormones on the synthesis of phospholipids of lung lamellar bodies was studied using lung tissue explants from 16- to 22-week gestational age human abortuses. Lung explants were incubated in a defined medium containing either no hormonal additions or insulin (2.5 micrograms/ml), cortisol (0.2 microgram/ml), or PRL (2.5 micrograms/ml), added alone or in various combinations. After 7 days of incubation, a purified lamellar body fraction was isolated from the explants. The effects of various hormone combinations on the relative rates of synthesis of lamellar body anionic glycerophospholipids during the last 24 h of culture were analyzed and compared to that of control explants. In control explants, 7.1% of the glycerophospholipid was synthesized as phosphatidylinositol, and 2.2% was synthesized as phosphatidylglycerol. Phosphatidylinositol synthesis was decreased significantly in explants incubated with cortisol alone, insulin plus cortisol, or insulin plus cortisol plus PRL (to 4.4%, 4.3%, and 3.7%, respectively), while phosphatidylglycerol synthesis was increased significantly in lamellar bodies from explants incubated with insulin plus cortisol or insulin plus cortisol plus PRL (to 5.5% and 5.7%, respectively). Although the relative rates of synthesis of lamellar body phosphatidylinositol and phosphatidylglycerol were significantly altered by hormones, the percentages of the total anionic glycerophospholipid were similar in all treatment groups (9.5%). The results of this study, therefore, are suggestive that lamellar body formation and glycerophospholipid composition are under hormonal control.

Female↗
PubMed1983

Gold.

Explore the source record for details and available documents.

Gold↗
PubMed1982

Defective internalization of low density lipoprotein in epidermoid cervical cancer cells.

Cells of an epidermoid cancer cell line of human uterine cervix, which possessed a high-affinity, specific receptor for low density lipoprotein (LDL), internalized and degraded [125I]iodo-LDL at a very low rate. In these cells, LDL did not stimulate cholesteryl ester synthesis, nor did it suppress 3-hydroxy-3-methylglutaryl coenzyme A reductase to the same extent as in the control cells. The binding of [125I]iodo-LDL by these cells was not decreased by preincubation of the cells in medium containing LDL. Using ferritin-labeled LDL (F-LDL) and electron microscopy, it was determined that at 4 degrees C the cells bound F-LDL in the same way as other cancer cell lines that did not have a defect in internalization. When these cells were warmed to 37 degrees C the F-LDL remained on the surface, whereas in cells from control cancer cell lines the F-LDL was internalized and was no longer observed on the cell surface. On the basis of the results of these studies it is concluded that cells of this epidermoid cancer cell line have a defective ability to internalize LDL.

Binding Sites↗
PubMed1982

Predictability of the glycerin test in the diagnosis of Ménière's disease.

The response of patients with suspected Ménière's disease to the glycerin test was reviewed in a prospective evaluation covering a 10 year period. Three hundred and eighty three patients with 495 suspect ears were tested and were classified as to hearing improvement 3 h post-orally administered glycerin. Two hundred twenty-five patients (265 ears) were diagnosed as Ménière's disease. Sixty-six percent of these ears showed significant hearing improvement by pure tone threshold and/or speech discrimination measurements with the glycerin test. The test protocol developed and revised at the University of Washington provides a differential diagnostic means of identifying endolymphatic hydrops which is a specific and practical test. It is easily available as a routine office procedure.

Adult↗
PubMed1981

The effects of hydrocortisone on the biosynthesis of sulfated glycoconjugates by human fetal lung.

In order to study the regulation of sulfated glycoconjugate biosynthesis during human fetal lung development, an in vitro organ culture system was utilized. Tissue explants of human fetal lung maintained in organ culture undergo hydrocortisone-potentiated morphological differentiation. Human fetal lung tissue synthesized several classes of sulfated glycoconjugates, including sulfated glycosaminoglycans, sulfated lipids, and a class of glycoproteins containing sulfated oligosaccharide chains. These sulfated oligosaccharides were not released from the polypeptides under alkaline conditions that cleave O-glycosidically linked chains and were not degraded by a variety of chemical and enzymatic treatments which degraded sulfated glycosaminoglycans. Explants maintained in culture during a 6-day period incorporated increasing levels of 35SO4 into glycoconjugates with increases of 7-fold into heparin and heparan sulfate, 3-fold into sulfated glycoproteins, and 2-fold into sulfated lipids. In comparison, incorporation of [3H]mannose into glycoconjugates increased 4-fold, and the incorporation of [3H]thymidine into DNA increased 2- to 3-fold during this culture period. Tissues maintained in culture in the presence of hydrocortisone (10(-7) M) showed an enhanced incorporation of 35SO4 into heparin and heparan sulfate and into sulfated glycoproteins during the culture period compared to cultures maintained in the absence of hydrocortisone. However, the levels of 35SO4 incorporated into lipids, [3H]mannose incorporated into glycoproteins, and [3H]thymidine incorporated into DNA were markedly decreased in cultures maintained in the presence of 10(-7) M hydrocortisone. Only small differences in the synthesis of chondroitin sulfates and dermatan sulfate were observed during the 6-day period that lung tissues were maintained in culture in the presence or absence of hydrocortisone. Thus, the biosynthesis of specific sulfated glycoconjugates by human fetal lung tissues is probably regulated by both developmental events and by circulating steroids.

Cell Differentiation↗
PubMed1981

Differentiation of type II cells of human fetal lung in vitro.

Lung tissue explants from mid-trimester human abortuses were maintained for 8 days in organ culture in medium with or without serum. Before the start of culture the cells lining the pre-alveolar ducts were undifferentiated and contained no lamellar bodies, the intracellular organelle that contains surfactant. After 4 days in organ culture, the epithelium lining the pre-alveolar ducts was composed of differentiated type II cells containing numerous lamellar bodies. During the 8-day culture period there was increased incorporation of [3H]choline into phosphatidylcholine and disaturated phosphatidylcholine. In addition, the specific activity of phosphatidate phosphohydrolase, a regulatory enzyme in lung phospholipid synthesis, increased 4-fold during the culture period. Lamellar bodies isolated by differential centrifugation from explants maintained in culture for 7 days had the characteristic ultrastructure described for this organelle. Lamellar bodies were isolated from explants which had been incubated with [14C]glycerol. When the glycerophospholipid composition of lamellar bodies was analyzed it was found that the majority of the radiolabeled glycerol (74%) was incorporated into phosphatidylcholine and into the anionic phospholipids, phosphatidylglycerol (5%) and phosphatidylinositol (6%). Thus, human fetal lung explants maintained in organ culture contain differentiated type II cells which synthesize surfactant characteristic of human fetal lung at 36 to 38 weeks of gestation.

Cell Differentiation↗
PubMed1981

Multihormonal regulation of surfactant synthesis by human fetal lung in vitro.

Explants prepared from the lung tissue of human abortuses of 20-22 weeks gestational age were incubated in defined medium without serum. These tissues developed the capacity for surfactant synthesis within 4 days. The ductular epithelium differentiated into type II pneumonocytes that contained numerous lamellar bodies. These morphological changes were accompanied by an increase in the rate of choline incorporation into phosphatidylcholine as well as an increase in the phosphatidylcholine content of the explants. Cortisol (0.2 micrograms/ml) plus PRL (2.5 micrograms/ml), when added to the medium from the beginning of the culture period, caused a 2- to 3-fold increase in the rate of choline incorporation into phosphatidylcholine, as measured on the second, fourth, sixth, and eighth days of incubation, as well as an increase in the phosphatidylcholine content of the explants. However, when administered alone, neither cortisol nor PRL affected phosphatidylcholine synthesis. In explants incubated with cortisol plus PRL there also was a stimulation of lamellar body secretion into the prealveolar ducts. The lamellar bodies in epithelial cells were larger in cortisol- plus PRL-treated tissue than those in nontreated tissues. Increases in phosphatidylcholine synthesis and lamellar body secretion also were observed in tissues incubated with insulin (2.5 micrograms/ml), cortisol, and PRL in combination or with insulin and cortisol in combination. The stimulatory effect of cortisol plus insulin on phosphatidylcholine synthesis, however, was significantly less than that of cortisol plus PRL or cortisol plus insulin plus PRL. It is suggested that human fetal lung development is under multihormonal control and that PRL and cortisol serve to increase surfactant synthesis and secretion.

Choline↗