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Biomedical subjects

S Cataland

Publications and source records attributed to S Cataland.

At least 37 records · Page 2Linked to original sources

Improvement of high-density lipoprotein-cholesterol levels. Ambulatory type I diabetics treated with the subcutaneous insulin pump.

Twelve ambulatory patients (six women and six men; mean age, 29 years) with type I diabetes were treated with a continuous subcutaneous open-loop insulin pump in an attempt to effect better glucose control. Hemoglobin A1, mean blood glucose, total cholesterol, total triglycerides, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), and the cholesterol/HDL-C ratio were assessed monthly before and after glucoregulation from five to 14 months (mean, nine months). Mean HDL-C levels increased significantly (52 +/- 4 to 60 +/- 5 mg/dL); mean cholesterol/HDL-C ratios decreased significantly (4.46 +/- 0.43 to 3.89 +/- 0.39). Mean values for triglycerides, total cholesterol, and LDL-C, all initially normal, did not change. Both mean Hb A1 levels and glucose levels fell from 11.2% +/- 0.5% to 9.8% +/- 0.5% and 177 +/- 15 mg/dL to 128 +/- 12 mg/dL, respectively. Insulin requirements decreased from 0.80 +/- 0.08 to 0.61 +/- 0.05 units/kg/24 hr. These results may favorably alter the prediction for development of accelerated atherosclerosis in type I diabetics.

Adolescent↗

Effects of amino acids and gastric inhibitory polypeptide on insulin release in dogs.

Insulin release following intravenous administration of an amino acid solution with and without a simultaneous infusion of varying amounts of porcine gastric inhibitory polypeptide (GIP) was studied in dogs. Group I received a 10-amino acid mixture (300 mosmol/kg iv) at 16.6 ml/min for 1 h; group II, amino acid mixture plus 0.5 micrograms.kg-1.h-1 porcine GIP; group III, amino acid mixture plus 1.0 micrograms.kg-1.h-1 of GIP; group IV (a and b) received either 0.5 or 1.0 micrograms.kg-1.h-1 of GIP alone. Compared to group I, groups II and III had a greater insulin response during the first 30 min of the infusion. Group] IV (a and b) showed no insulin release. Glucose concentrations showed no significant change in all groups. From these results, it is concluded that insulin release after intravenous infusion of an amino acid mixture plus GIP is greater than after amino acids or GIP alone. It appears that this effect is more pronounced in the early phase of insulin release.

Amino Acids↗

Gastrin Responses to a test meal in patients with familial medullary thyroid carcinoma.

The serum gastrin response to a standard test meal was evaluated in patients with familial medullary thyroid carcinoma (MTC) and in normal subjects. Patients with MTC and elevated plasma calcitonin levels had a lower gastrin response to the test meal than did normal persons or MTC patients who had normal calcitonin levels postthyroidectomy. There was no significant difference between the mean gastrin response of the normal group and that of the MTC patients with normal calcitonin levels. The serum gastrin response was studied before and after thyroidectomy in four patients. In all four, the post-operative response was greater than the preoperative one . We conclude that patients with MTC may have reduced gastrin responses to a test meal. This effect may be related to circulating calcitonin, somatostatin, or other factors related to familial MTC.

Adolescent↗

Spurious elevations in glycosylated hemoglobin (HbA1) secondary to hypertriglyceridemia.

Measurement of glycosylated hemoglobin (HbA1) is frequently helpful to clinicians in treating patients with diabetes, since a number of studies show that this reflects a reliable index of diabetic control over time. There are several methods of measuring HbA. The chromatographic method is the most frequently used and is the standard method for large demand. We recently encountered a patient with diabetes mellitus who had substantial lactescent plasma secondary to hypertriglyceridemia that falsely raised the HbA1 level. We examined the patient in detail and determined that triglyceride concentrations greater than 1,750 mg/dL would falsely raise the HbA1 levels. In vitro studies performed by adding lipemic plasma to a control sample confirmed this. Thus, spurious elevations in HbA1 can occur in patients with lactescent plasma. This would further complicate the already existing interrelationship between glucose intolerance and hypertriglyceridemia.

Chromatography↗

Diabetes responsive to intravenous but not subcutaneous insulin: effectiveness of aprotinin.

Patients with diabetes that is insensitive to subcutaneous insulin but sensitive to intravenous insulin have recently been described. We have studied this phenomenon is five female diabetics (14 to 31 years of age) who required excessive amounts of insulin (2.5 to 30.0 units per kilogram of body weight per day) to avoid recurrent ketoacidosis. Known causes of insulin resistance were excluded. All patients had normal responses to conventional doses of intravenous insulin (0.35 to 0.9 unit per kilogram per day). Four patients required continuous intravenous infusion of insulin for one to six months. When a mixture of aprotinin (a protease inhibitor) and regular porcine insulin was given subcutaneously, conventional doses (0.7 to 1.4 units per kilogram per day) produced euglycemia; plasma levels of free insulin rose, and ketonuria disappeared. Four patients had episodes of spontaneous, severe hypoglycemia before and during aprotinin therapy, necessitating continuous infusion of glucose for two to 14 days. Although no insulin was administered, hyperinsulinemia (50 to 2000 muU of free insulin per milliliter [359 to 14,350 pmol per liter]) was present. These findings suggest excessive degradation or sequestration of insulin at the site of injection.

Adolescent↗

Pancreatic polypeptide in acute pancreatitis and small-bowel infarction in dogs.

Serum and urine concentrations of pancreatic polypeptide (PP) were measured during experimental acute hemorrhagic pancreatitis and small-bowel infarction in dogs. The mean serum PP concentration in animals with pancreatitis increased markedly after 1 hr and remained elevated, while the mean serum PP concentration in the animals with infarction showed a late trend to increase. The urine PP concentration in pancreatitis increased nonsignificantly, whereas, during bowel infarction, there was no increase. In the infarction group, PP clearance correlated with the serum PP concentration. During pancreatitis, PP was cleared independently of the serum PP concentration. The results suggest that during acute hemorrhagic pancreatitis there is an acute release of PP related to immediate cell injury in the pancreas. The high serum concentration of PP may lead to an override of the normal renal handling of PP. In small-bowel infarction there may be a delayed mode of PP release.

Acute Disease↗

Vagal release of IR-VIP and IR-gastrin from the isolated perfused rat stomach.

The effects of electrical stimulation of the vagus at varying pulse widths on the release of immunoreactive VIP (IR-VIP) and IR-gastrin have been investigated, using the isolated perfused rat stomach preparation. Electrical stimulation of vagal trunks at a pulse width of 0.1 msec duration yielded no change in basal IR-VIP levels whereas a pulse width of 5.0 msec produced a prompt sustained increase. Stimulation at either pulse width evoked gastrin release. Atropine blocked the vagal release of IR-gastrin but not IR-VIP whereas hexamethonium blocked both responses. Exogenously administered porcine VIP, at concentrations mimicking endogenously released levels, was used in an attempt to reproduce the effects observed by vagal stimulation. Exogenous VIP had no effect on gastrin or somatostatin-like immunoreactivity (SLI) release. These in vitro studies support a role for VIP as a neurotransmitter released from the stomach by low-threshold non-cholinergic vagal fibres, but involving autonomic ganglia.

Animals↗

Gastric inhibitory polypeptide hypersecretion in diabetes mellitus: effect of sulfonylurea treatment.

We studied gastric inhibitory peptide (GIP) in response to a mixed meal in both adult-onset diabetics and normal controls. The adult-onset diabetic group was also studied for immunoreactive GIP (IR-GIP), insulin, and glucose with a test meal before and after tolazamide therapy. Mean basal and meal-stimulated IR-GIP concentrations were greater (P less than 0.05) in the adult-onset diabetic group than in normal controls. With treatment, mean fasting glucose significantly decreased (P less than 0.05) from 206 +/- 14 to 162 +/- 11 mg/dl, and postprandial glucose concentrations were reduced (P less than 0.05) between 5-180 min. In contrast, after 1 month of treatment with tolazamide, IR-GIP concentrations were not significantly altered. Further, basal and postmeal serum insulin levels were significantly higher (P less than 0.05) after tolazamide therapy. We conclude that the enteroinsular axis in terms of IR-GIP is overactive in adult-onset diabetics; tolazamide therapy does not appear to effect its meal-stimulated response.

Adult↗

Blunted pancreatic polypeptide responses in children with obesity of Prader-Willi syndrome.

Serum pancreatic polypeptide (PP), gastric inhibitory polypeptide (GIP), insulin and glucose responses to meal stimulation were studied in 10 normal weight patients, 13 normal obese patients and 7 patients with Prader-Willi syndrome (PWS) associated obesity. Serum and plasma concentrations of PP, glucose, insulin and GIP were obtained at 15 min intervals from 0-180 min. after a 275 K calorie meal. Basal and peak responses of glucose, for patients with PWS were significantly lower when compared to normal or obese controls. Basal and peak insulin responses in PWS were significantly greater than those of the normal controls but still less than those of the obese controls. Basal GIP concentrations in the patients with PWS were significantly less than normals and their peak response was less than the obese control group. No significant differences in basal or peak PP responses were noted between normal and obese controls. All 7 patients with PWS had abnormal PP responses. Five failed to show significant PP release after the stimulation; one had a peak response to 130 pg/ml while the 7th patient (PB) had an exaggerated response to 2000 pg/ml. The 6 patients with low or no response had basal PP values of 62 +/- 12 pg/ml and a mean PP peak response of 78 +/- 15 pg/ml. This observation of blunted PP response in a human model of hyperphagia and obesity parallels the animal models and suggests PP may have a significant role in appetite control.

Adolescent↗

Thyrotoxicosis and a thyrotropin-secreting pituitary tumor causing unilateral exophthalmos.

Hyperthyroidism due to a TSH-secreting pituitary tumor has been noted by a number of investigators. We describe a unique case in which a 17-yr-old female presented with clinical hyperthyroidism, a goiter, and unilateral exophthalmos. Serum T4, free T4, and T3 (RIA) were consistently elevated along with elevated TSH levels (range, 10-100 microunits/ml). Skull x-rays and computed tomography scan revealed a tumor invading the right orbit. Other pituitary function studies were normal and LATs was undetectable. Surgery performed resulted in 70% removal of the pituitary tumor and confirmed the presence of tumor infiltration into the right orbit. TRH tests done pre- and postoperatively (patient still clinically hyperthyroid with elevated T4 and TSH levels) showed TSH and PRL responsiveness. Electron microscopy of the tumor demonstrated features typical of pituitary thyrotrophs. Monolayer cultures of pituitary cells released TSH over time into the media but did not respond to TRH stimulation. Pituitary adenoma tissue content of immunoreactive TSH was 65 microunits/g wet tissue and demonstrated immunosimilarity with human standard. We conclude that the patient had a TSH-secreting pituitary tumor responsive to TRH stimulation.

Adenoma, Chromophobe↗

Effect of isocaloric exchange of dietary starch and sucrose in humans on the gastric inhibitory polypeptide response to a sucrose load.

Ten men and nine women aged 35 to 55 consumed two diets for 6 weeks each in a cross-over design. The diets were composed of identical natural foods and 30% of the calories as either sucrose or wheat starch. Carbohydrate, fat and protein supplied 43, 42, and 15% of the calories, respectively. The dietary pattern consisted of two meals divided so as to provide 10% of the calories at breakfast (7:00 to 8:30 AM) and 90% of the calories at dinner (4:30 to 6:30 PM). Initial body weights were essentially maintained. The gastric inhibitory polypeptide response after a sucrose load (2 g/kg body weight) was significantly greater (P < 0.01) after th subjects consumed the sucrose rather than the starch diet. The gastric inhibitory polypeptide response was significantly greater (P < 0.01) after 6 weeks on diet than during pretest. These results suggest that the increases in insulin levels observed after sucrose feeding may be mediated by an effect on the enteric hormone gastric inhibitory polypeptide.

Adult↗

Metabolic responses of Zucker fatty and lean rats fed carbohydrate diets ad libitum or in meals.

In order to study the metabolic effects of dietary sucrose on Zucker rats, young male fatty and lean rats were fed ad libitum or in meals (2 hours/day) for 4 weeks. Diets contained 54% carbohydrate as either sucrose, invert sugar or cooked cornstarch. A genotype effect (fatty versus lean) occurred with the activities of liver and adipose tissue lipogenic enzymes, relative total fat pad size and soluble adipose tissue protein levels in both ad libitum- and meal-fed rats, whereas a genotype effect occurred with food intake and relative liver size only in meal-fed rats and with body weight gain only in ad libitum-fed rats. The significance of diet effects varied with genotype and feeding pattern. The sucrose effect (sucrose versus starch) occurred with food efficiency and body weight gain, activities of liver lipogenic and gluconeogenic enzymes, relative liver size, relative total fat pad size and soluble adipose tissue protein levels in both ad libitum- and meal-fed rats, and with adipose lipogenic enzyme activities in meal-fed rats. The disaccharide effect (sucrose versus invert sugar) occurred with the activities of liver lipogenic enzymes, relative total fat pad size and soluble adipose tissue protein levels in ad libitum-fed rats and was greater in lean than in fatty rats. The data demonstrate that the Zucker fatty and lean rat can be used as sensitive models to study differential effects of dietary carbohydrate.

Adipose Tissue↗