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Biomedical subjects

K Levin

Publications and source records attributed to K Levin.

At least 19 recordsLinked to original sources
PubMed1990

High resolution single photon emission computerized tomography (SPECT) 99mtechnetium-dimercapto-succinic acid renal imaging: a state of the art technique.

The 99mtechnetium-dimercapto-succinic acid renal scan has become the gold standard for evaluating renal parenchymal pathology. The traditional pinhole technique provides 2-dimensional imaging. Recent application of high resolution single photon emission computerized tomography (SPECT) has provided the means to obtain even greater cortical detail. With 360-degree imaging and computer reconstruction, SPECT provides coronal, sagittal and transaxial imaging. We prospectively compared the SPECT and pinhole techniques in 33 patients (65 renal units) ranging in age from 2.5 months to 18 years. Both scans were obtained in all patients. All scans were reviewed by an independent interpreter. Using SPECT imaging, diagnostic information was enhanced in 46 of the 65 kidneys (71%). Of the 24 kidneys that appeared "normal" by pinhole imaging 15 (63%) had defects on SPECT imaging. High resolution SPECT imaging improves the ability to identify cortical defects and visualize asymmetry of cortical thickness compared to standard pinhole imaging.

Adolescent↗
PubMed1990

Lower serum magnesium level after exposure to cold in women with primary Raynaud's phenomenon.

Serum levels of magnesium (s-Mg), calcium (s-Ca), potassium (s-K) and sodium (s-Na) were measured in 80 women with primary Raynaud's phenomenon (RP) and in 24 age-matched female controls recruited from a population survey. The blood samples were taken after a 40-min standardized whole body cooling test. The mean s-Mg level in the group with RP was significantly lower than in the controls (0.81 +/- 0.05 vs. 0.86 +/- 0.07 mmol l-1, P less than 0.05). One year later, 66 members of the RP group and 22 members of the control group were investigated further, but without any exposure to cold. No differences in mean s-Mg values were found between the groups. The mean s-Mg level was significantly higher in the blood samples taken later without cold exposure than at the initial examinations after exposure to cold in the RP group, but not in the controls. The s-Mg level was lower after exposure to cold in 82% of the women with RP, compared to 45% of the controls (P less than 0.001). No differences in the other electrolytes were found. It is concluded that exposure to cold under standardized conditions may decrease the s-Mg level in women with primary RP. Further studies of the role of magnesium in patients with RP are required.

Adult↗
PubMed1988

Thyroid cancer: the case for total thyroidectomy.

Since there are no prospective studies concerning the treatment of thyroid cancer, there continues to be a considerable disagreement about the 'best' or most appropriate form of surgical treatment for patients with papillary or follicular thyroid cancer. Some surgeons recommend selective treatment depending upon the type of thyroid tumor and stage of the disease. Some advocate thyroid lobectomy and isthmusectomy, some near total thyroidectomy, and some total thyroidectomy for patients with papillary and follicular thyroid cancer. Total thyroidectomy for thyroid cancer would be the treatment of choice for virtually all patients with thyroid cancers if it could be done without complications. We therefore reviewed 160 consecutive patients who had total thyroidectomy for suspected or proven thyroid cancer to determine the complication rate of total thyroidectomy. One hundred and three patients had primary operations, 57 had reoperations with completion of total thyroidectomy and 124 had thyroid cancer. Serious complications (i.e. vocal cord paralysis or hypoparathyroidism) included two cases of transient bilateral recurrent nerve palsy, two patients with presumed transient unilateral vocal cord paralysis, three recurrent laryngeal nerves that were purposely sacrificed because of invasion of the nerve, and one case of permanent hypoparathyroidism. Two other patients developed postoperative wound infections. Only one of the permanent complications, the case of permanent hypoparathyroidism, could have been avoided by a lesser procedure. The experienced surgeon can perform a total thyroidectomy with minimal morbidity, and this procedure has certain theoretical and practical advantages. It should not be done, however, if it will result in a significant complication rate and, in selected patients, it may be preferable to leave a small amount of thyroid tissue to protect the blood supply to the parathyroid glands or recurrent laryngeal nerve.

Humans↗
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↗
PubMed1977

Calorimetry, a time-honored technique with a potential in analytical work and cellular biology.

Different types of calorimeters are briefly reviewed, stressing those instruments likely to be of interest in the clinical chemistry laboratory. The unspecific nature of the measuring procedure is emphasized and various pitfalls likely to cause analytical errors are pointed out. Recent work is reviewed where calorimeters have been used as analytical tools for the determination of glucose, protein, enzymes, and other substances. The results generally compared favorably with those obtained by conventional analytical procedures. In recent reports the time per analysis has been brought down to 2 min, with sample volumes in the micro range. Valuable information on the coagulation process has been obtained by use of calorimetry. I also review studies showing that intact cellular elements such as human blood cells, bacteria, and spermatozoa can successfully be investigated with calorimetric techniques. In particular, studies on human blood cells stimulated with various agents appear to be able to give valuable diagnostic information. I believe that new designs of microcalorimeters have placed an easily handled tool at the disposal of the worker in a clinical laboratory and that use of this tool can contribute to the development of our discipline.

Bacterial Physiological Phenomena↗
PubMed1976

Studies on subclinical hypothyroidism with special reference to the serum lipid pattern.

Subclinical hypothyroidism is an example of the impact of technology on the concept of a disease. It denotes a condition in which laboratory findings, at least including a raised serum thyrotropin (s-TSH), indicate hypothyroidism in the absence of clinical signs or symptoms of this disease. One reason for attention to cases of subclinical hypothyroidism is the publication of reports, from the time before introduction of the s-TSH assay, that hypercholesterolaemia precedes other evidence of thyroid failure with attendant risks of ischaemic heart disease and other atherosclerotic manifestations. The present investigation, which concerned the lipid pattern in sublinical hypothyroiism, offered no support for such a concept of hypercholesterolaemia as a premonitory sign of hypothyroidism. Furthermore, no significant differences were found between the serum levels of cholesterol and triglycerides before and after the administration of a thyroxine dose, necessary to suppress the s-TSH into a normal range, in cases of sublinical hypothyroidism. Nor were there any changes during this therapy in body weight, ECG, or Hb levels, which represent important parameters often found to be abnormal in overt hypothyroidism. From a practical point of view, subclinical hypothyroidism probably can be regarded as a state in which reduction of thyroid activity has been compensated by an increased s-TSH secretion to maintain a clinically euthyroid state. When no goitre is found, the rationale of treatment of this condition remains to be proved.

Cholesterol↗