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Biomedical subjects

C A Robinson

Publications and source records attributed to C A Robinson.

At least 91 records · Page 5Linked to original sources
PubMed1984

Clinical significance and partial biochemical characterization of lactate dehydrogenase isoenzyme 6.

We report nine patients with a sixth band, migrating cathodic to lactate dehydrogenase 5, appearing on routine electrophoresis for serum lactate dehydrogenase (LD, EC 1.1.1.27). Eight of these patients died during their hospitalization. Acidosis, hypotension, and sepsis were the common clinical conditions preceding the band's appearance. In several cases the band appeared transiently. We examined tissue samples from two of the cases, finding LD-6 in liver and skeletal muscle but not in heart. In randomly selected autopsy tissues, LD-6 was detected consistently in liver and skeletal muscle, sometimes in spleen, kidney, and adrenal tissue, but never in heart. Biochemical studies indicate that the LD-6 isoenzyme is not an artifact or an immunoglobulin complex, is larger than the other LD isoenzymes, contains an M-subunit but not an H-subunit, has an isoelectric point in the pH range of 9.0-9.6, and is more heat stable than LD-5.

Adolescent↗
PubMed1983

Analysis of amoxapine, 8-hydroxyamoxapine, and maprotiline by high-pressure liquid chromatography.

Two high-pressure liquid chromatography procedures are presented for the routine analysis of two new antidepressant drugs, amoxapine (Asendin) as well as its active metabolite and maprotiline (Ludiomil). Recovery rates were excellent with both methods of extraction. Method 1, for amoxapine and its metabolites, was linear up to 1,000 ng/ml. Sensitivity for the parent drug was 10 ng/ml and, for the active metabolite, 25 ng/ml. Within-run coefficients of variation (CV) were 4.57% for 8-hydroxyamoxapine and 3.84% for amoxapine. Method 2, for maprotiline, was linear from 10 to 1,000 ng/ml. Intraassay CV was 3.2%. Reliable, yet simple, methods for monitoring these drugs are needed in order to establish firmly the pharmacological data important to appropriate patient therapy.

Amoxapine↗
PubMed1983

Denture aesthetics: an evaluation of laymen's preferences.

The purpose of this study was to evaluate whether the lay public perceives anterior teeth selected by William's typal matching method as aesthetically pleasing. The theory was tested by laymen responding to questions about photographs of three edentulous male and three edentulous female patients. These patients were selected as representatives of square, tapering, and ovoid facial forms. The photographs were portrait views of the patients wearing different dentures displaying square, tapering, and ovoid teeth. Substantiation for typal match was found in the square female, square male, and the ovoid female patients. Responses to the photographs demonstrated a preference for square tooth forms over ovoid, and then tapering. Overall, ovoid teeth were preferred for females and square teeth were preferred for males.

Attitude↗
PubMed1983

Lymphocyte phenotype and function in pseudolymphoma associated with Sjögren's syndrome.

Lymph node (LNL) and salivary gland lymphocytes (SGL) from three patients with pseudolymphoma and primary Sjögren's syndrome (1(0)SS) were characterized with monoclonal antibodies to demonstrate (a) a predominance of T cells (greater than 80%) reactive with anti-T cell antibodies OKT4 (greater than 70%) and OKT8 (less than 20%); (b) a high prevalence of activation antigens (greater than 50% of cells reactive with antibody OKT10 and anti-Ia antibody); (c) polyclonal B cells (8-15% of all cells expressing kappa or lambda); and (d) a specific B cell subset defined by reactivity with antibody B532 that was not present in their peripheral blood. In vitro functional studies showed that both SGL and LNL provided T helper activity for immunoglobulin synthesis and that this activity could be abolished by treatment with antibody OKT4 plus complement. The SGL and LNL exhibited little natural killer, antibody-dependent cellular cytotoxicity, or cytotoxic T cell activity. Normal karyotype was observed in SGL, LNL, and peripheral blood lymphocytes (PBL) from these patients. These findings indicate that pseudolymphoma in 1(0)SS results from the infiltration of salivary glands and extraglandular tissues by nonneoplastic T helper cells. Monoclonal antibodies provide an important tool to distinguish pseudolymphoma from non-Hodgkins (B cell) lymphomas that have a markedly elevated incidence in 1(0)SS patients. Our finding of T helper cells in pseudolymphoma tissues supports the hypothesis that chronic stimulation of B cells by helper T cells leads to eventual escape of a malignant B cell clone.

Aged↗
PubMed1982

Use of monoclonal antibodies to analyze peripheral blood and salivary gland lymphocyte subsets in Sjögren's syndrome.

Using monoclonal antibodies to cell surface antigens, we studied lymphocyte subsets in 15 patients with primary Sjögren's syndrome. The absolute number of OKT8-positive cells (reactive with T suppressor/cytotoxic cells) was significantly decreased in such patients (353 +/- 186/mm3) compared to age-matched controls (631 +/- 150/mm3) (P less than 0.001). The number of OKT4-positive cells (reactive with T helper/inducer cells) was comparable in both groups (932 +/- 588/mm3 versus 1.073 +/- 290/mm3). The ratio of OKT4/OKT8-reactive peripheral blood lymphocytes was increased (greater than 2.4) in 67% of these patients and ranged from 1.0 to 6.4 (normal = 1.8 +/- 0.3). OKT4-positive cells were the predominant subset in lip biopsy specimens stained with immunofluorescence or immunoperoxidase techniques; the OKT4/OKT8 ratio exceeded 3.0 in all 5 patients examined. In 1 patient with pseudolymphoma, a lymph node biopsy specimen contained 80% T cells with an OKT4/OKT8 ratio of 3.2. Thus, OKT4-positive cells predominated in the peripheral blood lymphocytes as well as in sites of inflammation in primary Sjögren's syndrome. The decreased number of OKT8-positive cells in primary Sjögren's syndrome was probably not caused by circulating autoantibody, since patients' sera did not react with normal OKT8-positive cells. Functional studies using pokeweed mitogen demonstrated that T helper cell activity for immunoglobulin synthesis was contained in the OKT4-positive subset in both normal and patients' peripheral blood lymphocytes. Removal of OKT8-positive cells by complement-mediated lysis did not lead to increased immunoglobulin synthesis or production of rheumatoid factor. The identification of peripheral blood lymphocyte subsets by use of monoclonal antibodies and the relationship of these subsets to tissue infiltrates and autoantibody production provide further insight into the pathogenesis of primary Sjögren's syndrome.

Adolescent↗
PubMed1982

Laboratory evaluation of the Boehringer Mannheim "Diagnostic M" automated discrete analyzer.

We evaluated a new multiple-channel chemistry analyzer, the Boehringer Mannheim "Diagnostic M." This instrument can perform 25 tests at the rate of 120 1.3-mL serum samples per hour. The instrument may be run in either a profile mode or single-test mode. In the single-test mode only the necessary reagent is pumped. the instrument is computer controlled. We compared it with the Technicon SMAC, SMA 12/60, and SMA 6/60. It demonstrated excellent precision, linearity, lack of interference, ease of operation, and satisfactory comparison with values obtained by the Technicon methods.

Autoanalysis↗
PubMed1981

Quantitation of plasma warfarin concentrations by high performance liquid chormatography.

A rapid, sensitive, and specific high performance liquid chromatographic (HPLC) method for the quantitative analysis of warfarin in plasma is described. The method involves an extraction from acidified plasma, removal of basic substances, and reextraction into ether. The method is sensitive (0.06-9.0 microgram/ml) and precise (coefficient of variation less than 2%) and makes use of a Bondapak C-18 column. Several methods have been reported for the analysis of warfarin; each has some disadvantage in terms of specificity, sensitivity, reproducibility, or convenience. A fluorometric method (1) was rapid, but in our hands was neither precise nor sensitive and yielded values consistently higher than the proposed method. An HPLC method (2) that incorporated a Permaphase column and dioxane as the mobile phase did not perform at all with a Bondapak C-18 column. Gas-liquid chromatography involved derivatization (3), which did not afford reproducibility in our laboratory. Two other published HPLC methods (4,5) showed interference from diazepam. The method described in this paper is specific, accurate, and convenient. It has sufficient sensitivity to measure low warfarin levels, is linear to 9 microgram/ml, and is free of interference by common drugs. The clinical utility of this method is illustrated with three case reports.

Adult↗
PubMed1980

Frentizole therapy in systemic lupus erythematosus.

Seven corticosteroid dependent patients with active systemic lupus erythematosus (SLE) were given frentizole in order to assess its effect on their clinical manifestations. Three patients exhibited slight clinical improvement, 2 patients did not change, and 2 deteriorated. Five of the 7 patients developed subclinical and reversible liver damage related to frentizole. This study, although preliminary and uncontrolled, suggests that frentizole is of limited value in the management of patients with SLE.

Adult↗
PubMed1979

Computed tomographic evaluation of pear-shaped bladder.

Computed tomography (CT) was used to distinguish between pelvic lipomatosis and idiopathic inferior vena caval thrombosis as a cause of a pear-shaped bladder seen on intravenous urography. The findings on CT were explicit in explaining the patient's clinical problem.

Adult↗
PubMed1978

Histologic grading of Wilms' tumor as potential prognostic factor: results of a retrospective study of 26 patients.

A histologic grading system based on tumor differentiation was applied in a retrospective study of 26 patients with Wilms' tumor to determine if it might provide an index to prognosis. The results were compared to those obtained by applying a histologic classification based on the presence or absence of individual histologic structures to the same tumors. Low grade tumors with predominance of differentiated structures--glomeruli and tubules--were associated with a better cure rate than high grade tumors composed mainly of undifferentiated spindle elements. The presence of undifferentiated large cells correlated with poor cure rate. The findings suggest that histologic grading may be valid as a prognostic factor in Wilms' tumor.

Adolescent↗