Biomedical subjects

H M Drew

Publications and source records attributed to H M Drew.

7 recordsLinked to original sources

PubMed1986

Performance of solid-state 48 detector gamma counter using solid phase total thyroxin and free thyroxin assays.

We evaluated the performance of an automated 48 detector KinetiCount gamma counter using solid phase reagents for total thyroxin (TT4) and free thyroxin (FT4). Interassay coefficients of variations (CV) for both total T4 and free T4 ranged from 5.4% to 13%. Between-method correlation coefficients were 0.9798 for TT4 and 0.8844 for FT4. Detection limits for TT4 and FT4 were 3 micrograms/l and 3 ng/l, respectively. TT4 was linear up to 200 micrograms/l. The recovery of TT4 was between 99 to 101%. A computer-stored standard curve for total T4 was stable over a 6-day period. The 48 counting chambers demonstrated stability over a 45-day period with no significant changes in counting efficiency (p greater than 0.5). Precision between the 48 chambers gave a CV of 1.6%. Crosstalk between chambers was less than 0.3% with count rates up to 80,000 cpm. We conclude that the KinetiCount immunoassay system using solid phase separation technology performs well and is suitable for routine clinical use.

Evaluation Studies as Topic↗

PubMed1983

Clinical evaluation of two direct procedures for free thyroxin, and of free thyroxin index determined nonisotopically and by measuring thyroxin-binding globulin.

We have investigated the clinical utility of two direct radioimmunoassays for free thyroxin, an enzyme-inhibition immunoassay, and a direct measurement of thyroxin-binding globulin (TBG) by radioassay. All assay methods correctly identified greater than or equal to 90% of euthyroid, hyperthyroid, and hypothyroid patients who had normal TBG concentrations. In patients with altered TBG concentrations, none of the assays correctly classified all categories of patients. However, the direct assays of free thyroxin concentrations were able to classify correctly more patients with altered TBG concentrations than did the free thyroxin index methods. The free thyroxin index methods evaluated may be acceptable for routine use, if the concentration of thyroxin and the measurement of TBG capacity are reported along with the index value. Patients with altered TBG concentrations included a group of euthyroid pregnant patients. Significant decreases in free thyroxin in the third trimester were detected by all the assays studied. For patients in the first and second trimester, the mean free thyroxin concentration measured varied with the assay method.

Evaluation Studies as Topic↗

PubMed1982

Abnormal fatty acid breath tests in cancer patients, with nutritional correlation.

In a group of cancer patients selected to exclude common causes of abnormal lipid absorption, we have examined this function using a breath test. Abnormal breath tests of fatty acid absorption (FABT) are found in most cancer patients, as has been previously claimed. These tests are abnormal in both quality (delayed peak in nine of ten patients, and quantity (reduced maximum peak in five of ten patients) of fatty acid absorption. In many patients abnormal FABT is not due to chemotherapy. Our preliminary results indicate no definite malabsorption mechanism but more stringent tests of absorption need to be applied. Malnutrition is common in cancer patients, even in those with little or no weight loss, and some of the malnutrition may be related to abnormal lipid absorption or to other disturbed aspects of lipid metabolism.

Adult↗

PubMed1981

Endogenous insulin secretion measured by C-peptide in maturity-onset diabetes controllable by diet alone.

Endogenous insulin secretion was quantified in patients with maturity-onset diabetes (MOD) whose diabetes was controllable solely by caloric regulation as primary therapy. Insulin was used adjunctively only and persistent attempts were made to withdraw it as weight loss occurred in response to diet. Insulin secretory capacity was measured by C-peptide response during a standard 100-g oral glucose tolerance test in 24 patients who achieved normalization of plasma glucose level as a result of dietary therapy alone. Summed C-peptide levels for the diet-controlled diabetic patients was 7.8 +/- 0.7 pmol/mL as compared with 6.1 +/- 0.45 pmol/mL for a group of ten normal-weight, nondiabetic volunteers.

Adult↗

PubMed1979

A study of age-dependent changes in thyroid function tests in adults.

Total serum thyroxine (T4), triiodothyronine (T3), T3 resin uptake (T3U), thyrotrophin (TSH), and reverse T3 (rT3) were measured in 209 healthy adults 20--89 yr old. Mean T4 values for men were stable throughout life, but in females under age 60, T4 values were significantly higher than in older women. Values for T3U in males were significantly higher than in females throughout all decades, although females had a significant increase in T3U after age 60. TSH values increased significantly in females over age 60. Throughout all decades, males had stable TSH levels that were slightly higher than the female results before age 60 and lower thereafter. Mean serum T3 declined similarly for both sexes with increasing age, although not to the extent previously reported. Men had significantly higher mean rT3 values over all decades than females, although female rT3 levels decreased after age 50 whereas males maintained stable values. The physiologic reasons for these findings may be due to sex-related changes in binding proteins and alterations in metabolic clearance rates, production, and degradation of these hormones with increasing age.

Adult↗

PubMedDate not supplied

Exacerbation of diabetes mellitus by antibodies to exogenous insulin.

Three nonobese maturity-onset diabetic patients has worsening hyperglycemia and ketonuria unresponsive to marked increases in dose of beef/pork insulin. In each case, significant cross-reactivity with human insulin of anti-insulin antibodies generated by exogenous insulin therapy was demonstrated by competition experiments using solid phase radioimmunoassay. Normal or near normal levels of endogenous insulin secretion as determined by C-peptide radioimmunoassay were measured in the three cases. The sequence of events that we postulate to explain the initial presentation with severe hyperglycemia in each case begins with a slight deficiency in endogenous insulin reserve. Mild hyperglycemia then led to treatment with beef/pork insulin. The beef component elicited an antibody response that not only bound exogenous insulin, reducing its effectiveness, but also inactivated each patient's endogenous human insulin, provoking an exacerbation of underlying mild diabetes.

Adult↗

PubMedDate not supplied

Recovery from decompensated non-insulin-dependent diabetes mellitus: studies of C-peptide secretion.

Eleven non-insulin-dependent diabetic patients presented with decompensated hyperglycemia. Nine had pronounced ketonuria, five with acidosis. In seven cases, precipitating factors were identified. In the other four cases, including three cases of diabetic ketoacidosis, no identifiable triggering events were present. In each case, recovery from the initially decompensated diabetic state occurred. Eventually, all patients were managed by diet alone. Seven patients demonstrated nondiabetic glucose tolerance tests (GTT). Several patients underwent stressful situations after "recovery" without recurrence of hyperglycemia. Glucose-stimulated C-peptide levels were determined postrecovery. C-peptide secretion was in the normal range and, in fact, was identical, in relation to glucose levels, to that in a group of nondiabetic volunteers. In 6 of the 11 cases, C-peptide secretion was measured at the time of initial presentation. These levels were markedly lower than comparable values during the GTT postrecovery. Non-insulin-dependent diabetes, even when presenting in a decompensated state, is subject to a considerable degree of reversibility and even recovery to a nondiabetic state in some cases. Recovery is associated with a return to normal C-peptide secretion.

Adult↗