ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryThirteen cystic fibrosis and 12 normal strains of skin fibroblasts obtained from the Institute for Medical Research were compared for their degree of production of cyclic adenosine 3′:5′-monophos-phate in response to isoproterenol and prostaglandin E1. There were no significant differences in their quantitative responses in content of cyclic AMP at two different times whether these cells were growing exponentially or were already confluent. All strains responded similarly to the presence of two types of phosphodiesterase inhibitor. The averaged initial rates of the response to isoproterenol in exponentially growing cells were also similar for the two sets of strains. Although response differed greatly between strains, the response of each strain was relatively reproducible.SpeculationIt appears that cystic fibrosis skin fibroblasts and normal skin Fibroblasts are equally sensitive to isoproterenol. The likely explanation for a previous observation of a 3-fold higher response to isoproterenol is that an improbable selection of the five cystic fibrosis strains and the five normal strains occurred.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryMuscle cultures from a patient with I-cell disease showed the characteristic morphologic and biochemical abnormalities previously observed in cultured fibroblasts. At early stages of myoblast growth, there were numerous inclusions. Biochemically, the intra-cellular activities of β-galactosidase, β-hexosaminidase, and α-mannosidase were reduced to 1,14, and 5%, respectively, of control values, and this was accompanied by elevated levels of β-hexosaminidase and α-mannosidase in the culture medium. Cultures from the patient did not fuse as well as controls; however, when well-developed myotubes possessing distinct cross-striations were present, these no longer had inclusions. In the muscle biopsy from this patient, only β-galactosidase was decreased to approximately 50% of the mean control value whereas β;-hexosaminidase and α-mannosidase activities were increased as compared to controls. These data suggest that the I-cell mutation is expressed during early myogenesis but not in well-differentiated myotubes or mature muscle fibers.SpeculationThe expression of the I-cell mutation in cultured fibroblasts as compared to immatureversusmature muscle suggests that the intracellular localization of acid hydrolases into lysosomes may occur via different pathways in different tissues and may also differ at various stages in development.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryWeight gain and food intake were measured in unstressed nonpregnant and pregnant guinea pigs fedad libitum.Nonpregnant females consumed 33.2 ± 0.5 g·day“−1of pellet diet and did not demonstrate a consistent pattern of weight gain. The average daily food intake of pregnant animals increased linearly from 38 g·day−1at 27 days to over 60 g·day−1near term, and the average maternal weight gain was 13.3 g·day−1.Using sterile technique, polyvinyl catheters were inserted under anesthesia into the carotid and femoral arteries of these animals. Animals recovered spontaneously, and catheters remained patent for up to 4 wk. The effect of surgical and anesthetic stress was evaluated by measurement of food intake and metabolite levels after surgery. In the nonpregnant animals, blood glucose decreased immediately after surgery (4.76 ± 0.36versus5.65 ± 0.25;P< 0.05), whereas the pregnant animals responded with a substantial increase in blood glucose (7.57 ± 0.48versus5.87 ± 0.33;P< 0.05). Lactate was increased intraoperatively in both groups (1.76 ± 0.22versus1.11 ± 0.07, nonpregnant; 1.80 ± 0.17versus1.10 ± 0.08, pregnant). The pregnant animals differed from the nonpregnant animals with regard to the pattern of changes in blood ketones after surgery. The nonpregnant animals achieved steady state within 1 day after surgery, whereas the pregnant animals required 4 days for recovery. Food intake and maternal weight gain were markedly reduced during the recovery period for the pregnant animals.Blood metabolite levels were measured in well-fed, unstressed pregnant and nonpregnant guinea pigs. Using measurements made after the third postoperative day, the unstressed pregnant animals demonstrated a progressive decline in blood glucose levels, reaching levels significantly below those of nonpregnant animals at 55 to 60 and 60+ days. Arterial concentrations of lactate, pyruvate, β;-hydroxybutyrate, acetoacetate, and free fatty acids did not change consistently with gestation and were not significantly different from nonpregnant values.SpeculationIn animal studies, it is frequently difficult to differentiate the effects of advancing gestation from the effects of acute sample collection. Extension of these techniques of chronic catheterization to other areas of guinea pig metabolism and to other small mammalian species may provide more uniform conditions for the study of the comparative physiology of gestation and fetal development.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryThe measurement of125I-insulin specific binding to erythrocytes obtained from seven infants and children with various hypoglycemic syndromes showed a significant increase in six patients with recurrent, documented, symptomatic hypoglycemia (percent specific125I-insulin binding 9 to 14versus6.1 ± 1.4%; mean ± 2 S.D. for 13 controls). The increase was due to an increased number of receptors sites per cell rather than to increased affinity for insulin. The patients incuded three children with nesidioblastosis, all after 90% pancreatectomy, two with leucine sensitivity, and two with glycogen storage disease type I. One of the patients with leucine sensitivity, who for 2 years before the study had no hypoglycemia, had normal insulin binding (4.8%). All seven patients had normal fasting basal plasma insulin values (<10 μU/ml). Thus, symptomatic hypoglycemia correlated better with increased125I-insulin binding than with plasma insulin values.Furthermore, Diazoxide therapy in two patients caused a mild but consistent decrease in the number of insulin receptor sites, and the institution of continuous nocturnal nasogastric feedings in a patient with glycogen storage disease type I was followed by amelioration of the hypoglycemia and a marked increase in125I-insulin specific binding from 5.2 to 9.5%.Speculation125I-Insulin binding to receptors of various cells or tissues may be altered in a variety of clinical situations. Thus, erythrocyte insulin binding sites are significantly decreased in adult-onset, nonobese diabetics that are non-insulin dependent. This patient population has chronic hyperglycemia, the opposite state from our patients with chronic hypoglycemia. Inasmuch as our patients had increased insulin binding sites and normal basal plasma insulin values, we may speculate that prolonged hypoglycemia and therefore tissue glucose depletion may be associated with an increase in insulin receptors and therefore an increase in the insulin bioeffect. This may explain why these patients become hypoglycemic in the presence of normal plasma insulin values. Increased erythrocyte125I-insulin binding may prove to be another index of long-term hypoglycemia and may perhaps prove more reliable than isolated plasma insulin or glucose values.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryWe studied the effect of hyperviscosity on plasma glucose concentration, endogenous glucose production, and plasma insulin concentration in 12 term mixed breed newborn lambs. After a 7-hr fast, 0.45% saline was infused at a constant rate for 6 hr during which time hourly plasma glucose and 3-hourly plasma insulin concentrations were determined. A glucose turnover determination by the prime-constant infusion technique using3H6radiolabeled glucose was performed at a steady state. An exchange transfusion was then carried out using maternal packed red blood cells in six lambs to produce hyperviscosity and using maternal whole blood in six other lambs to maintain normoviscosity. After the exchange transfusion, a second study identical to that in the pre-exchange period was carried out. There was no significant difference in the mean plasma glucose concentration (mg/dl; mean ± S.E.) between groups during the first turnover period (pre-exchange transfusion) [103 ± 4.9 (Normoviscous)versus96 ± 4.8 (Hyperviscous)), but during the postexchange transfusion turnover period, the plasma glucose concentration was lower in the hyperviscous than in the normoviscous group [89 ± 4.3 (Normoviscous)versus76 ± 4.0 (Hyperviscous)] (P<0.05.) Endogenous glucose production declined from the first to the second glucose turnover determination in both groups, but there was no significant difference between the normoviscous and hyperviscous groups. Plasma insulin concentrations were similarly low in both groups suggesting suppression in the fasted state. The data suggest that the hyperviscosity acts as an independent variable to depress plasma glucose concentration, the mechanism of which is still undefined.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

SummaryPlasma immunoreactive cationic trypsin(ogen) levels were determined in 32 control subjects and 43 patients with varying degrees of pancreatic insufficiency including 35 with cystic fibrosis (CF) and eight with Shwachman's syndrome. In six CF infants less than 2 years of age, plasma trypsin(ogen) levels were significantly elevated (97.3 ± 62.2 ng/ml) above the normal range for nine controls (7.0 ± 5.9 ng/ml;P< 0.025). Four of these infants had steatorrhea, three of whom had undetectable duodenal trypsin activity after stimulation with secretin-cholecystokinin. In two CF infants, molecular size fractionation by gel filtration of plasma followed by radioimmunoassay of the column fractions demonstrated that trypsinogen was the only immunoreactive species in the circulation.In contrast, in older CF patients with steatorrhea (mean age, 15.3 ± 4.6 years), plasma cationic trypsin(ogen) levels were undetectable or low (1.1 ± 1.7 ng/ml). This finding clearly distinguished them from older CF patients without steatorrhea (mean age, 14.3 ± 3.9 years) in whom cationic trypsin(ogen) levels were significantly higher (23.3 ± 17.6 ng/ml;P< 0.01). The mean trypsin(ogen) concentration in the older CF patients without steatorrhea did not differ from the mean value for 23 normal subjects of similar age. Plasma cationic trypsin(ogen) levels in two Shwachman's patients with steatorrhea (0.19 and 0.86 ng/ml) were significantly lower than the values found in six Shwachman's patients without steatorrhea (5.9 ± 2.3 ng/ml;P< 0.025). Furthermore, in nine older CF patients and eight Shwachman's patients, circulating trypsin(ogen) levels were highly correlated with duodenal trypsin output after secretin-cholecystokinin stimulation (r = 0.946,P< 0.01; r = 0.899,P< 0.01, respectively). These results suggest that in CF infants high levels of circulating trypsin(ogen) persist even in those with complete pancreatic insufficiency. In older CF patients and those with Shwachman's syndrome, however, circulating trypsin(ogen) accurately reflects residual pancreatic function.SpeculationCystic fibrosis (CF) infants often possess viable but ductally obstructed pancreatic tissue, which may be destroyed with disease progression. The correlation between pancreatic exocrine function and circulating trypsin(ogen) in older CF patients and Shwachman's patients, however, indicates that ductal obstruction is not a prominent feature in these patients.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID