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Biomedical subjects

B Solomon

Publications and source records attributed to B Solomon.

At least 37 records · Page 2Linked to original sources

Current trends in the management of Graves' disease.

Members of the American Thyroid Association were invited to participate in a survey of the management of Graves' disease. One primary case and several variations were provided, which differed in respect to age, sex, goiter size, severity, etc. The questionnaire was based on the format used in a similar survey of members of the European Thyroid Association. The aim of the survey was to determine 1) how expert thyroidologist employ diagnostic procedures for this disorder, and 2) the choice of therapy of the three treatment options and its manner of implementation. Questionnaires were sent only to clinically active members. The overall response rate was 62%. Data analysis was possible on 52% of members surveyed and was performed using SPSS and a specific Fortran program. In the laboratory evaluation of the primary case a radioiodine uptake, scan, serum total T4, and basal TSH were requested by 92%, 47%, 83%, and 66%, respectively, with 84% of respondents using an ultrasensitive TSH assay. For management of the primary case, radioiodine treatment was the first choice of 69% of the respondents. Antithyroid drugs were used briefly (3-7 days) before 131I by 28%, whereas 41% said they would employ thioureas after 131I. Of those using 131I, 66% tailored the dose to achieve euthyroidism as the goal of therapy, while 34% aimed for hypothyroidism requiring T4 replacement. Only 30% of respondents chose thioureas as a first line of treatment (72% propylthiouracil; 28% tapazole). The duration of drug therapy was a predetermined fixed interval for 80% of the respondents, with 90% treating for 1-2 yr. Other specific trends in diagnostic approach and therapeutic preferences were identified for the eight variations on the primary case problem.

Adrenergic beta-Antagonists

Vocal changes in patients undergoing radiation therapy for glottic carcinoma.

A prospective evaluation of vocal changes in patients receiving radiation therapy for T1 and T2 (AJC) glottic carcinoma was undertaken in January 1987. Vocal analysis was performed prior to radiotherapy and at specific intervals throughout the radiation treatment program. The voicing ratio was extrapolated from a sustained vowel phonation using the Visipitch interfaced with the IBM-PC. Preliminary observations suggested three distinct patterns of vocal behavior: 1. reduced voicing ratio with precipitous improvement within the course of treatment, 2. high initial voicing ratio with reduction secondary to radiation induced edema, with rapid improvement in the voicing component after the edema subsided, and 3. fluctuating voicing ratio during and following treatment. Enrollment of new patients and a 2-year follow-up of current patients was undertaken.

Aged

Localization of a highly immunogenic region of carboxypeptidase A recognized by three different monoclonal antibodies and their use in the detection of subtle conformational alterations in this enzyme region.

Three murine monoclonal antibodies (mAb 100, 104, and 121) elicited against carboxypeptidase A (CPA) were prepared and characterized. All three mAbs recognize the same or partially overlapping sites of CPA. This is corroborated by the lack of antibody additivity in the ELISA assay carried out in the presence of pairs of mAbs, the similarity in molecular weight of the immunocomplex formed between CPA and one of the mAbs in the presence of another, and also a competition experiment in which one of the mAbs was labeled enzymatically. The three mAbs do not affect the enzymatic activity of CPA. Even at high concentrations, they do not recognize carboxypeptidase B (CPB) in spite of the similar tertiary structure and the 50% homology in amino acid sequence with CPA. This antigenic determinant is located on one of the four cyanogen bromide fragments of CPA. On the basis of the known sequences of the two enzymes, criteria which predict high antigenicity, and experimental data using synthetic peptides, such a determinant was found to be located within the amino acid sequence from residues 209 to 218 of the CPA molecule. The mAbs prepared detect conformational alterations in the above enzyme epitope when the enzyme is exposed to various conditions. The binding of the mAbs to CPA adsorbed onto a polystyrene plate is characterized by apparent binding constants higher by 1 or 2 orders of magnitude than those characterizing the interaction of the mAbs with CPA in solution. The mAbs also readily detect both conformational alterations of CPA on treatment with urea and subtle, reversible conformational alterations on removal of zinc from the active site of the enzyme.

Amino Acid Sequence

Alterations in magnesium and zinc metabolism in thyroid disease.

Magnesium (Mg) and zinc (Zn) status was assessed in subjects to evaluate the effects of thyroid diseases on Mg and Zn metabolism. Plasma and red blood cell (RBC) concentration and peripheral blood mononuclear cell (MNC) content of Mg and Zn, and 24-hour urinary excretion of Mg, Zn, creatinine (Cr), calcium (Ca), sodium (Na), and potassium (K) were measured in 11 thyrotoxic, 29 hypothyroid, and 25 euthyroid control subjects. Serum albumin, alpha 2-macroglobulin, and the binding of Zn to albumin were also determined. Plasma and RBC Mg concentrations were low in half of the hyperthyroid subjects, but mean values were not significantly different from controls. Urinary excretion and clearance of Mg were lower in hypothyroid subjects, but differences were removed when expressed relative to Cr excretion and clearance. Similar patterns were noted for urinary Ca, Na, and K, suggesting that their reduced excretion reflects alterations in renal hemodynamics. Plasma Zn was lower in hypothyroid subjects and correlated with serum albumin; MNC Zn and urinary Zn were also low. Plasma Zn concentration was normal and serum albumin significantly lower in the hyperthyroid group than in the control group. Further, RBC Zn content was significantly lower in hyperthyroid subjects, and inversely related to plasma thyroxine concentration. The hyperthyroid group also excreted significantly greater amounts of Zn than controls, indicative of a catabolic process. This increased urinary loss may reflect a shift in the distribution of plasma Zn between ultrafilterable and Zn-albumin complexes. In summary, this study provides evidence for marked alterations in Zn homeostasis in persons with thyroid disease. Whether the observations indicate deficiency states and have clinical implications will require further investigation.

Adolescent

Eponyms.

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Eponyms

Illness and health behaviour in Addis Ababa and rural central Ethiopia.

This paper examines the results of health surveys among 544 randomly selected households (2829 people) in seven kebele (urban dwellers' associations) in Addis Ababa and Kaliti, an industrial suburb of Addis Ababa, and in four rural villages in two peasant associations. The major objective was to study illness distribution and health behaviour among different socioeconomic and cultural groups in urban and rural communities within the context of available health resources, national health policy and planning. Results show that in spite of the rapid expansion of health services since the Ethiopian revolution serious problems of allocation and access persist. Higher illness prevalance rates were found in rural areas (23.2%), Kaliti (25.5%) and in the low socioeconomic kebele in Addis Ababa (23.9%) than in the high socioeconomic kebele (16.5%), but rural/urban and intraurban differences were greater than reported here due to underreporting. One-third of all illnesses were treated by modern services, 19.9% by self care and 26.0% by traditional medicine and transitional healers, with 21.5% of all illnesses not being treated. Utilization rates varied with type and duration of illness, socioeconomic level, age, sex and place of residence. The role of distance and other contact barriers, treatment outcome and availability of private clinics and alternative health resources in utilization is also evaluated. Coverage of the modern health services was associated with socioeconomic status and mobility of patients as well as availability of health services.

Adolescent

Minor neurological indicators and developmental function in preschool children.

An attempt was made to determine whether neuromaturational indicators (soft neurological signs) were associated consistently with specific areas of developmental function in 5-year-old children. Fifty-eight children were assessed over two diagnostic sessions. One involved administration of the Pediatric Exam of Educational Readiness (PEER) by pediatric fellows; the other consisted of administration of the McCarthy Scales of Children's Abilities (MSCA) by trained psychoeducational specialists. Data indicate that children who exhibited a greater number of minor neurological indicators had a high likelihood of experiencing difficulty with visual-perceptual, fine motor, and gross motor tasks of the PEER and the MSCA. What is more important, no relationship was found between aggregates of minor neurological indicators and performance on linguistic, memory, sequencing, quantitative, verbal, or preacademic sections of these diagnostic instruments. This information suggests that physicians should limit their interpretation of such signs when evaluating young children with academic difficulties. Additional data must be accumulated before the role of neuromaturational signs can be fully understood.

Child, Preschool

Interaction of carboxypeptidase A with monoclonal antibodies.

Several mouse monoclonal antibodies to carboxypeptidase A (CPA) were prepared and purified, and their interaction with the enzyme was investigated. CPA is a well-characterized zinc-containing exopeptidase exhibiting peptidase as well as esterase activity. The antibodies obtained could be classified as follows: antibodies inhibiting mainly the peptidase activity of the enzyme, antibodies inhibiting mainly its esterase activity, antibodies affecting both activities, and antibodies which bind to the enzyme but have no marked effect on its catalytic properties. Binding constants of approximately 10(6) M-1 were obtained for most of the antibody-enzyme complexes tested. Additional information on the effect of the monoclonal antibodies on the active site of CPA was obtained by determining the change in the circular dichroism spectra of arsanilazotyrosine-248 carboxypeptidase A occurring as a result of the interaction of the enzyme with the antibodies studied. These findings suggest that CPA possesses at least three different specific antigenic sites, and that the active site of the enzyme for its peptidase activity differs from that for its esterase activity, though both sites seem to overlap to a considerable extent.

Animals

Transfer of insulin receptors and of glucose transport-inducing proteins onto phospholipid vesicles.

Insulin receptors and glucose transport-inducing proteins have been extracted from rat liver membranes onto positively charged lipid bilayer vesicles. The extraction was carried out during the incubation of the vesicles with lipid vesicles caused an overall enhancement of specific insulin binding and of glucose transport inducement. The latter has been inferred from the oxidation rate of transported glucose through a spherical bilayer membrane entrapping the oxidizing glucose oxidase. Glucose transport is not enhanced by insulin binding, indicating that the two functions baecome dissociated when the proteins are transferred from the plasma membrane onto the bilayer vesicles.

Animals

Interaction of glucose oxidase with phospholipid vesicles.

The interactions between glucose oxidase and phospholipid vesicles were investigated. The investigations were carried on molecules adsorbed on the outer surfaces as well as entrapped in the interior of the vesicles . The adsorption of glucose oxidase on the surfaces of egg egg licithin vesicles, containing varying amounts of cholesterol and stearoylamine was measured by determining the free fraction of glucose oxidase detected in the filtrates. In general an enhancement of enzymic activity was observed upon interaction with the vesicles. The enhancement depends on the lipid composition of the vesicles and the surface concentration of the adsorbed glucose oxidase. It reached a maximal value at a surface concentration of 1.4-10(11) molecules/cm2 (approximately 7.1 - 10(4) A2/molecule) on pure phosphatidylcholine vesicles and about 6.5 - 10(10) molecules/cm2 (approximately 16 - 10(4) A2/molecule) when the vesicles contained cholesterol or cholesterol and stearoylamine. CD measurements indicated that the change in enzymic activity of the adsorbed glucose oxidase was accompanied by conformational modification of the enzyme. In order to entrap glucose oxidase into the vesicles, the lipid was sonicated in the presence of the enzyme. After removal of the free and adsorbed enzyme the amount of the entrapped enzyme was determined by measuring its activity after disintegration of the vesicles with Triton. The enzymic activity of the entrapped glucose oxidase served as a measure for the permeability of the bilayer membrane of the lipid vesicles to glucose. Addition of insulin to the suspension of vesicles containing the entrapped glucose oxidase increased the permeability of glucose by up to 9 - 10(-8) cm/s. This value is the lowest estimate based on the assumption that one glucose oxidase molecule was entrapped in every vesicle.

Binding Sites

Adenosine 3',5'-cyclic monophosphate and morphology in Neurospora crassa: drug-induced alterations.

Grown in liquid culture in the presence of a variety of structurally unrelated drugs, mycelia of wild-type Neurospora assume a colonial or semicolonial growth habit similar to that of known morphological mutants. Drugs that produce these morphological changes include atropine, theophylline, histamine, and several of the quinoline-containing antimalarials. Each of these drugs decrease the endogenous adenosine 3',5'-cyclic monophosphate (cAMP) concentration of mycelia as a result of their effect on the activity of adenyl cyclase, the cAMP-dependent phosphodiesterase, or both. The evidence indicates a relationship between the degree of morphological abnormality, the degree to which intracellular cAMP is reduced, and the action of the drugs on the adenyl cyclase and phosphodiesterase.

Adenylyl Cyclases