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Biomedical subjects

N Waldeck

Publications and source records attributed to N Waldeck.

26 records · Page 2Linked to original sources
PubMed1983

Outpatient use of intermediate- and short-acting semisynthetic human insulins.

To determine if semisynthetic human insulins are useful in the outpatient management of insulin-dependent diabetes, the conditions of eight patients were evaluated for three months using short- and intermediate-acting insulins. No complications of either insulin preparation were observed. Hemoglobin A1c levels were decreased from 8.4% to 6.9% during human insulin use, and, in addition, normal hemoglobin A1c levels were maintained in patients using portable insulin infusion pumps. These results were achieved because of the health care provision team and were not directly the result of human insulin. Semisynthetic human insulins were also associated with lower levels of circulating insulin antibody. These data indicate that both short- and intermediate-acting semisynthetic human insulins are effective in stringent diabetes metabolic control, provided adequate health care provision is available.

Adult↗
PubMed1981

Conformational changes in rat liver chromatin after liver regeneration.

N-Pyrenemaleimide, a fluorescent probe that specifically labels histone H3 of rat liver chromatin in situ, was used to monitor the accessibility of histone H3 in chromatin isolated from rat liver at different times during degeneration. At times of maximum DNA synthesis (18--24 h after hepatectomy), the accessibility of the probe was found to be markedly (40--50%) increased. This increase is abolished, however, by treatment of the chromatin fibres with high salt (2 M-NaCl) or detergent. Tryptophan fluorescence was also enhanced at points of maximum DNA synthesis, suggesting that some non-histone tryptophan-containing protein was being synthesized. The polarization of the labelled histone H3 is not markedly altered, suggesting that fibre aggregation or dissociation does not occur. Mononucleosomes extracted from sham-operated and hepatectomized animals did not exhibit any difference in binding to the probe. Also, analysis of the chromatin protein by electrophoresis on detergent- and acid/urea/ Triton-X-100-containing polyacrylamide gels showed no detectable difference in histone H3 : 1, H3 : 2 or H3 : 3 subclasses.

Animals↗
PubMed1981

Excessive circulating large molecular weight immunoreactive glucagon components in subjects with the idiopathic postprandial syndrome.

The glucagon RIA measures several molecular components in human plasma. Clinical disorders have been described associated with abnormal elevations of certain of these components. This report documents another clinical disorder, the idiopathic postprandial syndrome, which also appears associated with excessive circulating large molecular weight immunoreactive glucagon (IRG) components. During studies of glucose homeostasis in subjects with apparent idiopathic postabsorptive hypoglycemia, 80 subjects were evaluated using oral glucose tolerance tests; 18 subjects were found to have clinical and laboratory findings consistent with the disorder, and of these, 3 had markedly elevated basal total plasma IRG levels. Plasma IRG responses in the subjects after oral glucose or mixed meals were variable. Physical characterization of the excessive large molecular weight IRG components revealed molecular weight estimates of 300,000 and 345,000 daltons in 2 subjects and of more than 200,000 daltons in the third subject. The origin and chemical nature of this material is uncertain. None of these subjects had evidence for a glucagonoma, as supported by the virtual absence of detectable levels of native (3500-dalton) glucagon after gel filtration. Since the origin of the idiopathic postprandial syndrome as well as the origin and chemical nature of large molecular weight IRG components are unknown, the association of these two findings remains unclear but is clinically important in the differential diagnosis of the glucagonoma syndrome.

Adenoma, Islet Cell↗
PubMed1981

Comparison of oral glucose tolerance tests and mixed meals in patients with apparent idiopathic postabsorptive hypoglycemia: absence of hypoglycemia after meals.

The relationship between symptoms of idiopathic postabsorptive hypoglycemia and glucose homeostasis was evaluated by giving oral glucose tolerance tests (OGTT) and mixed meals to 18 patients and 16 controls. Chemical hypoglycemia after OGTT occurred as often in patients referred because of possible hypoglycemia symptoms, 18 out of 80 (23%), as in controls, 4 out of 16 (25%). After glucose, patients showed both clinical and chemical hypoglycemia (mean +/- SE plasma glucose, 48 +/- 3 mg/dl), but insulin, glucagon, and growth hormone responses were similar to controls. After mixed meals, no chemical hypoglycemia occurred in patients (mean plasma glucose, 79 +/- 3 mg/dl), yet 14 out of 18 (78%) had symptoms and/or signs consistent with hypoglycemia. No abnormality of glucose homeostasis was observed after meals that could account for symptoms or signs experienced by patients with idiopathic postabsorptive hypoglycemia. Since factors other than hypoglycemia appear to be involved, the disorder should be termed the idiopathic postprandial syndrome to avoid the connotation of chemical hypoglycemia.

Adult↗
PubMed1980

Serum thyroglobulin levels predict total body iodine scan findings in patients with treated well-differentiated thyroid carcinoma.

Forty-eight consecutive patients with treated thyroid carcinoma were studied with 131-I total body scans and serum thyroglobulin (hTg) levels. Serum hTg levels during thyroxine treatment accurately predicted scan results (chi square = 18.6, p < 0.001). All patients with negative scans (24 patients) had serum hTg levels (< 7 ng/ml whereas in patients with metastatic thyroid cancer (eight patients) they ranged from 11 to 690 ng/ml. In patients with iodine uptake confined to the thyroid bed (16 patients) serum hTg values ranged from 2 to 17 ng/ml. Serum hTg levels rose in patients with negative scans during hypothyroidism or after exogenous TSH suggesting that hTg levels are more sensitive than iodine scans in detecting residual thyroid tissue. Serum hTg levels could replace total body iodine scans in many patients with treated thyroid carcinoma.

Adult↗
PubMed1980

Postprandial hormonal responses to different types of complex carbohydrate in individuals with impaired glucose tolerance.

We have studied the effects of dextrose, rice, potato, corn, and bread on postprandial plasma glucose, insulin and glucagon responses in 11 subjects with impaired glucose tolerance. All carbohydrate loads were calculated to contain 50 g of glucose. The data demonstrate that 1) dextrose and potato elicited similar plasma glucose responses whereas rice, and bread elicited lower responses with corn intermediate; 2) dextrose and potato elicited similar plasma insulin responses whereas rice gave lower responses, with bread and corn intermediate; 3) all of the carbohydrate loads suppressed plasma glucagon with dextrose causing the greatest suppression. In conclusion, there is a range of plasma glucose, insulin, and glucagon responses to different complex carbohydrates in subjects with impaired glucose tolerance and the differences in plasma glucose responses may be of therapeutic value in controlling hyperglycemia.

Adult↗
PubMed1976

Liver plasma membranes from essential fatty acid-deficient rats. Isolation, fatty acid composition, and activities of 5'-nucleotidase, ATPase and adenylate cyclase.

Tod determine whether changes in unsaturation of fatty acids in rat liver plasma membranes might alter activities of membrane-associated enzymes, liver plasma membranes were prepared from rats fed purified diets lacking or supplemented with essential fatty acids. Two methods of membrane purification were used. A similar degree of purification was obtained with both methods for both depleted and control membranes, as indicated by marker enzyme purification. The proportion of essential fatty acids of the linoleate series was significantly lower in phospholipids from depleted rats. The specific activity of 5'-nucleotidase was lower, and the activity, V and apparent Km for total (Na+ +K+ +Mg2+)-ATPase were higher in the depleted liver plasma membranes. Arrhenius plots of total ATPase activity showed a discontinuity at the same temperature for both the depleted and control membranes. Activity with the depleted membranes was higher at all temperatures tested. Supplementation of deficient rats with a source of essential fatty acids (corn oil) restored V and apparent Km values to normal. Adenylate cyclase activity in the presence of fluoride, glucagon or glucagon plus GTP was significantly lower in the depleted plasma membranes.

Adenosine Triphosphatases↗