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Biomedical subjects

K Levin

Publications and source records attributed to K Levin.

At least 73 records · Page 4Linked to original sources
PubMed1984

Autoimmune thyroid dysfunction in the postpartum period.

The prevalence of thyroid disease was investigated in 460 Caucasian women after delivery. Thyroid microsomal antibodies (MsAb) were found in 44 (9.6%) of the women. These women appeared to have autoimmune thyroiditis. The changes in MsAb titers followed a predictable pattern with maximal values around 5-7 months postpartum. At this time 20 of these women had transient hypothyroidism and in some this was preceded by a thyrotoxic episode. The extent of postpartum hypothyroidism correlated well with the titers of MsAb in early pregnancy and in the postpartum period. Transient thyrotoxicosis occurred in eight women 5-7 months postpartum. TSH-receptor stimulating antibodies and/or high radioiodine uptake, suggesting Graves' disease, were detected in four of these women. Thus, after delivery, manifestations of autoimmune thyroid disorders, are remarkably common. In patients with autoimmune thyroiditis measurements of MsAb provide a good prognostic marker for the development of transient hypothyroidism.

Adult↗
PubMed1984

Inadequate hemolysis of erythrocytes on reagent strips at low pH causes false-negative readings.

Patients' urines gave an unexpectedly high percentage of false-negative results for erythrocytes on a reagent strip, even when the test field for ascorbic acid indicated that none of this substance was present to inhibit the test reaction. By adding known amounts of erythrocytes to normal urines, we found that this phenomenon was time-dependent and occurred with three different brands of reagent strips in urines having a pH below 6.0. Hemolysis of erythrocytes was totally inhibited below pH 5.1 after 4 h of incubation with 50 X 10(6) erythrocytes per liter. The inhibition is apparently caused by shrinkage of the erythrocytes, rending them insensitive to the hemolytic agents in the different reagent strips tested.

Detergents↗
PubMed1984

Free thyroxin index and direct measurements of free thyroxin compared for evaluating postpartum autoimmune thyroid dysfunction.

Measurement of free thyroxin (FT4) by a recently introduced commercial assay (Amerlex Free T4 RIA) was compared with the calculated free thyroxin index (FT4I) for serum from 104 postpartum women. Of these, 63 had transient thyroid dysfunction due to autoimmune thyroiditis, six had transient Graves' thyrotoxicosis, and 35 were euthyroid with no signs of autoimmune thyroid disease. The correlation between results for FT4 and the calculated FTI for 95 serum samples from women with no signs of autoimmune thyroiditis (r = 0.941; p = 0.0001) was almost identical to that for 270 serum samples from women with thyroid microsomal autoantibodies characteristic of autoimmune thyroiditis (r = 0.937; p = 0.0001). Furthermore, we observed no difference when the autoimmune group was subdivided according to low or high titers of thyroid microsomal antibodies. In no case did autoantibodies to thyroxin interfere with the FT4 assay. However, one woman had a spuriously low value for FT4I owing to interference by autoantibodies to triiodothyronine with the triiodothyronine resin uptake test. We conclude that the FT4 RIA assay provided diagnostic information in this group of postpartum women equivalent to that of the more elaborate procedure of determining FT4I.

Autoantibodies↗
PubMed1983

Comparison of glucagon, cAMP, and cGMP effects on lipogenesis in hepatocytes.

Control of lipogenesis by glucagon and cyclic nucleotide derivatives was examined in freshly isolated hepatocytes. [14C]Acetate was incorporated at a linear rate for 2 h into cellular lipids and for at least 6 h into medium lipids. About 80% of the incorporated label was recovered in fatty acids. Incorporation of [1-14C]acetate and 3H2O into cellular and medium lipids was inhibited by glucagon (K50 = 8 X 10(-10) M), dibutyryladenosine 3':5'-cyclic monophosphate (K50 = 7.5 X 10(-8) M), and guanosine 3':5'-cyclic monophosphate and its dibutyryl and 8-bromo derivatives, each with K50 = 2.9 X 10(-6) M. Glucagon (10 nM) reduced incorporation of [14C]acetate and 3H2O into fatty acid by 73 and 52%, respectively, and into cholesterol by 24 and 10%, respectively. When added together to hepatocytes at submaximally inhibitory concentrations, dibutyryl cAMP and dibutyryl cGMP exerted additive effects. However, maximal inhibitory concentrations of both produced the same effect as the addition of either nucleotide alone. Thus, this preparation of rat hepatocytes responded to physiological concentrations of glucagon and low concentrations of dibutyryl cAMP. Cyclic guanosine derivatives inhibited lipogenesis, but 100 times greater concentration was required when compared with dibutyryl cAMP. Dibutyryl cAMP and dibutyryl cGMP did not act synergistically.

Acetates↗
PubMed1982

Interictal behaviour in hospitalised temporal lobe epileptics: relationship to idiopathic psychiatric syndromes.

Temporal lobe epileptics undergoing psychiatric hospitalisation were contrasted with patients suffering idiopathic psychiatric syndromes or other epilepsies. Quantitative ratings from blind interviews conducted according to a protocol confirmed the appearance of a statistically distinctive behavioural profile, including the desire for social affiliation, circumstantiality, religious and philosophic interests, and deepened affects, among the temporal lobe epileptics.

Adult↗
PubMed1981

Blood loss, tissue weight and operating time in transurethral prostatectomy.

The possibility of statistically significant correlation between blood loss during transurethral prostatectomy (TURP) and weight of the resected tissue and/or duration of the operation was explored in 392 patients. All had been operated on by the same surgeon, and in all cases the peroperative blood loss, weight of resected tissue and length of operation were known. A highly significant correlation was found between blood loss and tissue weight, with an overall mean of 15 ml per gram. The severity of bleeding, however, increased with duration of the operation, from 5.2 ml per minute in the smallest glands (less than 10 g) to 20.3 in the largest (greater than 80 g). Speedier surgery is therefore one possibility of reducing blood loss in TURP. In most of the cases with heavy peroperative bleeding, the operating time exceeded one hour. Surgeons should therefore try not to undertake resections that cannot be completed within 60 minutes. If the surgeon is experienced and the estimated prostatic weight less than 30 grams, preoperative crossmatching of blood is not usually necessary.

Hemorrhage↗
PubMed1977

Divergent changes of serum 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine in patients with acute myocardial infarction.

The serum levels of thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (reverse T3, rT3), thyroxine-binding globulin and thyroid-stimulating hormone have been monitored in 13 patients with acute myocardial infarction. The major changes recorded were a transient decrease in T3 and a transient increase in rT3. They reached a nadir and a peak, respectively, within three days. A conceivable explanation for these alterations is that the monodeiodination of T4 is diverted from the activating pathway (T4 to T3) to the inactivating pathway (T4 to rT3).

Acute Disease↗
PubMed1977

Studies on replacement and suppressive dosages of 1-thyroxine.

Serum thyrotropin (TSH) levels were studied in 55 hypothyroid patients in order to determine adequate replacement and suppression dosages of 1-thyroxine (T4). In accordance with previous reports it was found that most patients had normal TSH levels and were clinically euthyroid at daily doses of 0.10-0.15 mg T4. None of the patients required a dose exceeding 0.20 mg. When the TSH levels normalized, serum thyroxine and serum triiodothyronine also fell to levels within their normal ranges. The effectiveness of various doses of T4 in suppressing the temporary rise in serum TSH concentration normally induced by thyrotropin-releasing hormone was examined in 57 patients treated with T4 for atoxic goitre or after subtotal surgical removal of such a goitre. The rise in TSH was not usually inhibited by a T4 dose of less than 0.20 mg, a finding which at least theoretically has implications for the adequate suppressive dose of T4.

Female↗