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Biomedical subjects

A Zeidler

Publications and source records attributed to A Zeidler.

50 records · Page 3Linked to original sources
PubMed1979

An 'artificial beta cell' for control of diabetes mellitus: effect on plasma glucagon levels.

We have investigated the use of a glucose-controlled insulin infusion system, or artificial beta cell. On the feedback day, mean plasma glucose was significantly effect of improved control on plasma glucagon levels. Five insulin-requiring diabetic subjects in stable control were hospitalized for two 24 h periods. During one, they were given their usual dose(s) of subcutaneous insulin. In the other, the 'feedback' day, insulin administration was under feedback control by the artificial beta cell. One the feedback day, mean plasma glucose was significantly-lower in all subjects. Variability in plasma glucose throughout the day was also significantly less on the feedback day. All five subjects showed a significant fall in serum immunoreactive glucagon levels on the feedback day, suggesting that the glucagon abnormalities of diabetes may be secondary to the insulin deficiency, rather than a second primary defect of diabetes.

Adult↗
PubMed1978

A prospective study of glucose tolerance, insulin, C-peptide, and glucagon responses in patients with pancreatic carcinoma.

Ninety-nine patients suspected of having pancreatic carcinoma were studied prospectively for carbohydrate tolerance. Thirty-two patients were proven subsequently to have pancreatic carcinoma; the remainder served as a control group. There was an increased incidence of carbohydrate intolerance in patients with pancreatic carcinoma compared to the control group. Insulin and C-peptide measurements during glucose tolerance tests suggest abnormal beta cell function and possibly insulin resistance as causes for this abnormality. Although factors related to malignancy in general could partly account for the results, a specific factor occurring in patients with pancreatic carcinoma must also be considered as it could serve as a marker for the early detection of this disease.

Body Weight↗
PubMed1976

Acute effect of ascorbic acid infusion on carbohydrate tolerance.

Large doses (1 to 2g/3 hr) of ascorbic acid were administered intravenously to normal weight and obese, nondiabetic subjects. Glucose tolerance and fasting plasma glucose levels were unaffected, despite a 3- to 8-fold rise in plasma concentrations of the vitamin. Infusion of ascorbic acid did not alter fasting serum insulin levels in normal subjects, but was associated with lower concentrations of hormone during an intravenous glucose tolerance test. Plasma glucose, serum insulin, growth hormone, and glucagon levels in obese subjects remained unchanged during the ascorbic acid infusion.

Ascorbic Acid↗
PubMed1976

Heterogeneity of plasma glucagon. Circulating components in normal subjects and patients with chronic renal failure.

Plasma immunoreactive glucagon (IRG) concentrations were measured in 36 patients with chronic renal failure (CRF) and 32 normal subjects. In addition, the components of circulating IRG were analyzed by gel filtration in the fasting state and after physiological stimuli. Fasting IRG was elevated (P less than 0.001) in CRF patients (534 +/- 32 pg/ml) compared with the levels found in healthy subjects (113 +/- 9 pg/ml). Oral glucose suppressed plasma IRG in CRF patients from a basal level of 568 +/- 52 to a nadir of 354 +/- 57 pg/ml (120 min). This degree of suppression (38%) was comparable to that found in normal subjects (basal = 154 +/- 20 to 100 +/- 23 pg/ml) at 120 min (35%). Intravenous infusion of arginine (250 mg/kg) resulted in a 71% rise in IRG in CRF patients and a 166% increase in normal subjects. Gel filtration of fasting plasma from CRF patients showed three major peaks. The earliest (A) was found in the void volume (mol wt greater than 40,000) and constituted 16.5 +/- 4.7% of the elution profile. The middle peak (B) eluted just beyond the proinsulin marker (approximately 9,000 mol wt) and constituted the largest proportion of the elution profile (56.5 +/- 3.4%). The third peak (C) coincided with the standard glucagon and [125I]glucagon markers (3,485 mol wt) and comprised 27.0 +/- 4% of the IRG profile. In contrast, only peaks A and C were found in fasting plasma of normal subjects (53.6 +/- 10.4% in A and 46.4 +/- 10.4 in C). After oral glucose, glucagon immunoreactivity in the 3,500 mol wt peak (C) was markedly suppressed, while the B peak in patients with CRF declined to a lesser extent. The A peak in both groups was unchanged. After an arginine infusion only the C peak increased in both groups of subjects. Gel filtration of plasma in 3 M acetic acid gave similar profiles to those obtained in glycine albumin buffer. Exposure of serum to trypsin indicated that the B and C peaks were digestible, while the A peak was resistant to the action of the enzyme. In one sample, peak C increased after a 2-h exposure of serum to trypsin. We conclude that circulating IRG in normal subjects and patients with CRF is heterogenous. The hyperglucagonemia of renal failure is largely due to an increase in IRG material of approximately 9,000 mol wt, consistent with proglucagon, although the 3,500 mol wt component is also considerably elevated (threefold). The significance of circulating IRG levels should be interpreted with caution until the relative biological activity of the three components is established.

Acetates↗
PubMed1976

Heterogeneity of plasma glucagon: patterns in patients with chronic renal failure and diabetes.

Immunoreactive plasma glucagon (IRG) in normal subjects and patients with chronic renal failure, diabetic ketoacidosis and diagetic hyperosmolar syndrome circulates in several forms. In the diabetic patients most IRG eluted coincidentally with the extracted, purified pancreatic hormone (MW3500), while in normal subjects a high molecular weight component predominated. In striking contrast, the major component of plasma IRG in patients with chronic renal failure was of intermediate size (MW +/- 9000), consistent with proglucagon. The accumulation of this form of IRG suggests that the kidney plays an important role in its metabolism. If there are differences in the biological activity of the various circulating components of IRG, the significance of immunoreactive glucagon levels in some disease states will require reassessment.

Diabetes Mellitus↗
PubMedDate not supplied

Symptoms of sexual dysfunction and depression in diabetic women.

Studies of sexual dysfunction in diabetic women have been less conclusive than those of sexual dysfunction in diabetic men. We examined the relationship between symptoms of sexual dysfunction, neuropathy, and depression in diabetic women. Diabetic women with neuropathy experienced significantly more symptoms of sexual dysfunction and depression than diabetic women without neuropathy. Furthermore, among women with neuropathy, there was a significant positive correlation between the degree of sexual dysfunction experienced and the degree of depression. These results indicate that depressive symptoms should be examined in studies of sexual dysfunction in diabetic women, and that a biopsychosocial approach is best for assessing sexual dysfunction in diabetic women.

Adult↗
PubMedDate not supplied

Components of variance for vibratory and thermal threshold testing in normal and diabetic subjects.

Quantitative sensory testing (QST) is commonly used in the assessment of diabetic neuropathy. However, little data are available on the reliability of tactile and thermal testing devices. Reproducibility of QST measures between centers has not been previously reported. This study was designed to validate QST testing procedures and determine if these devices are suitable for large scale multicenter clinical trials. Finger and toe vibratory (Vf, Vt) and thermal (Tf, Tt) thresholds were determined for ten normal individuals by a two-alternative forced-choice procedure using the Optacon Tactile Tester (OTT) and Thermal Sensitivity Tester (TST). Threshold measurements were reproducible between technologists and had a day-to-day coefficient of variation of Vf 20%, Vt 23%, Tf 41%, and Tt 95%. Thresholds were determined for 140 normal individuals at six centers. Mean threshold values between centers were not significantly different. Center-to-center coefficients of variation (CV) were Vf 44%, Vt 45%, Tf 47%, and Tt 87%. There was no significant difference in threshold measures with regard to sex, side studied, presence of calluses, or skin temperature. Vf thresholds significantly correlated with age (p < 0.01). There was no correlation between either vibratory or thermal thresholds in normal individuals, and nerve conduction velocities (NCV). Thermal and vibratory thresholds were determined for 98 diabetic patients. Diabetic subjects without clinical evidence of neuropathy were not significantly different from normal individuals, but diabetic patients with neuropathy had increased thresholds compared to normals (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Pituitary gonadal function in diabetic male patients with and without impotence.

Assessment of pituitary function was undertaken in diabetic male patients with and without impotence, and in normal subjects, using a combined gonadotropin releasing hormone (GnRH) and thyrotropin releasing hormone (TRH) test. Basal plasma levels of testosterone, gonadotropins, PRL and TSH were similar in the diabetic patients and controls. Following the administration of I.V. GnRH 150 microgram and TRH 500 microgram, diabetic patients with impotence demonstrated a lower LH response at 30 and 150 minutes and an increased PRL response at 20 minutes, which was statistically significant when compared to controls. FSH and TSH were similar in the diabetic patients and controls. The GnRH and TRH test was repeated in impotent diabetic patients while receiving 0.8-1 mU/kg/hr of insulin through an infusion pump. No difference in LH and PRL response could be demonstrated. These results demonstrate that following GnRH and TRH test, diabetic patients with impotence have a significantly different LH and PRL response than controls. In these patients acute control of hyperglycemia using an insulin infusion pump did not reverse the abnormal response.

Adult↗
PubMedDate not supplied

Polymorphic gene markers in Mexican-Americans residing in southern California.

The gene frequencies of nine different genetic polymorphic markers [ABO, MNS and P blood groups; haptoglobin, transferrin, Gc protein, complement (C3), properdin factor B and alpha 1-antitrypsin] were determined in 94 Mexican-Americans residing in the Los Angeles, California area. Comparisons with published data on Mexican-Americans living in other areas of the United States or in Mexico itself revealed no significant differences in the gene frequencies between this and previous studies. However, data from the current study demonstrated significant differences in ABO and haptoglobin allele frequencies compared to published non-Hispanic Caucasian data. These data suggest a large degree of genetic homogeneity in the Mexican-American population residing in the United States. Additional gene marker studies will be important to test this hypothesis and further define the degree of non-Hispanic Caucasian admixture in this population.

ABO Blood-Group System↗
PubMedDate not supplied

Glyburide and glipizide in treatment of diabetic patients with secondary failures to tolazamide or chlorpropamide.

We evaluated therapeutic usefulness of the second-generation sulfonylurea agents glyburide and glipizide in non-insulin-dependent diabetic patients who were secondary failures on chlorpropamide or tolazamide. Twenty patients were treated with glyburide, and 10 of them were subsequently treated with glipizide. Fasting and postprandial serum glucose, insulin, C-peptide, glycosylated hemoglobin, urinary C-peptide, and glucose levels all failed to show significant improvement. We concluded that both glyburide and glipizide proved ineffective in the treatment of secondary failures to first-generation sulfonylureas.

Blood Glucose↗
PubMedDate not supplied

Different HLA haplotypes in Mexican Americans with IDDM.

The study of HLA histocompatibility antigens and insulin-dependent diabetes mellitus (IDDM) in non-White populations may provide a unique opportunity to more accurately define the diabetes susceptibility gene(s) located within the HLA region. To determine whether HLA haplotypes differ between ethnic groups, we compared 105 HLA haplotypes from 55 Mexican-American IDDM patients with 272 haplotypes from 136 IDDM patients of non-Hispanic White descent. The accurate determination of genotypes and haplotypes requires the study of family units. Therefore, all diabetic patients in this study were from studies of families having one or more siblings with IDDM. In the Mexican-American group, HLA-DR3 and -DR4 were the most common HLA-DR alleles and were present in comparable frequencies in the non-Hispanic White group (HLA-DR3, 27% of Mexican-American and 29% of non-Hispanic White haplotypes; DR4, 46% of Mexican-American and 43% of non-Hispanic White haplotypes). However, the HLA-B/DR-containing haplotypes and haplotype frequencies differed between the two groups. Several common haplotypes (B8/DR3, B15/DR4) in the non-Hispanic White group occurred less frequently in the Mexican-American group. In contrast, uncommon haplotypes in the non-Hispanic White group comprised nearly 50% of the DR4-containing haplotypes (B35/DR4, B40/DR4, B44/DR4) in the Mexican-American group. Although both DR3- and DR4-haplotype frequencies differed significantly between the two groups, the relative frequency of DR3- but not DR4-containing haplotypes was similar in both ethnic groups. This adds to the evidence suggesting that different susceptibilities are provided by the haplotypes carrying the DR3 and DR4 alleles.

Alleles↗
PubMedDate not supplied

Hyperinsulinism complicating control of diabetes mellitus by an artificial beta-cell.

Serum free insulin concentrations were measured in diabetic subjects given insulin intravenously by a glucose-controlled insulin infusion system ("closed-loop" artificial beta-cell) in two experimental situations: hourly during the day while given their usual diet and at short intervals after administration of a standardized test meal. Three of four subjects showed sustained hyperinsulinism when compared with matched controls during a day on their usual diet. In two of the subjects, the insulin levels also exceeded those seen in those subjects on their usual dose of subcutaneous insulin. The glucose levels were not completely normalized in the three hyperinsulinemic subjects, and the insulin levels were significantly correlated with plasma glucose levels. After the test meal, all six diabetic subjects studied showed a delayed rise in insulin levels, when compared with six normal subjects, followed by an abrupt rise in insulin levels to peak levels more than seven times those seen in normal subjects. We conclude that significant hyperinsulinism may accompany feedback-controlled intravenous insulin administration. This should be considered in interpreting studies done with such systems, and in design of control algorithms for future systems.

Basophils↗