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Biomedical subjects

J E Davis

Publications and source records attributed to J E Davis.

At least 109 records · Page 6Linked to original sources
PubMed1986

Extending the linear range for kinetic reactions by considering the relationship between enzyme activity of the reagent and measurement intervals.

We show that the rate-concentration curve is sigmoidal for enzyme-catalyzed procedures that are commonly applied to rapid automated analyzers. Linear data can be obtained by judicious selection of the reagent enzyme activity (Vm) and the measurement interval (t1 to t2). For determination of substrate concentrations much less than Km, conditions that balance linearity with sensitivity and accuracy are obtained when Vm/Km = [ln (t2/t1)]/(t2-t1). We also present theoretical and experimental data that show the linear range can be extended to concentrations exceeding the Km value. We illustrate the application of theoretically appropriate conditions by analysis of procedures reported to be optimized. Familiarity with these concepts can obviate laborious and potentially misleading experimentation.

Allantoin↗
PubMed1985

Squamous cell carcinoma of cervix metastatic to ileal loop.

A case is presented of squamous cell carcinoma of the cervix with an isolated metastasis to an ileal loop six years after diversion and seven years after definitive treatment of the primary lesion with irradiation.

Carcinoma, Squamous Cell↗
PubMed1983

Clinical chemistry.

Explore the source record for details and available documents.

Blood Coagulation Factors↗
PubMed1982

Considerations in selecting a postvasectomy semen examination regimen.

The criteria for declaring a vasectomized man sterile have been the subject of debate for many years, yet most suggested regimens differ. The problem lies in the remaining unanswered physiologic questions of such a fundamental nature as to frustrate attempts to formulate a regimen based strictly on medical considerations. The rates of disappearance of sperm following vasectomy vary considerably among men. The physiologic basis for these variations are herein discussed for the first time. At present, regimens reflect, for the most part, social considerations, according to the values and perceptions of the individual physician. The problems raised by postvasectomy residual sperm and current formulation of regimens are described.

Ejaculation↗
PubMed1982

Monoclonal antibody to HLA-A3.

The monoclonal antibody GAP A3 detects the HLA allospecificity A3. Reactivity of the monoclonal was in exact concordance with the presence of the A3 antigen as defined by conventional alloantisera on a panel of 59 cells from individuals with well-characterized HLA antigens. Reactivity with GAP A3 segregated with HLA-A3 in a family where three of eight siblings inherited the paternal A3 antigen. GAP A3 precipitated appropriate 44,000- and 12,000-dalton bands on SDS-polyacrylamide gels under reducing conditions from an HLA-A3-positive, but not an HLA-A3-negative B lymphoblastoid cell line. Thus, by serological, familial, and biochemical criteria, GAP A3 defines the allospecificity HLA-A3.

Animals↗
PubMed1981

Methyl parathion persistence in soil following simulated spillage.

Simulated spillage of emulsifiable concentrate (E.C.) and microencapsulated formulations of methyl parathion on soil were studied. Persistence of residues from both formulations spilled as concentrates and as simulated from rinses were followed for up to 45 months. Spillage of encapsulated formulation resulted in the formulation of a solid cake-like deposit on the soil surface, which could be a particularly attractive hazard to small children. At 45 months, soil residues had decreased by 64% for emulsifiable concentrate spills, and 68% for the soil beneath the microencapsulated cake. Residue in the cake itself only decreased by 31%. Soil residue levels from simulated drum rinses were essentially innocuous by 45 months for the emulsifiable concentrate and by one year for the microencapsulated material. The leaching of methyl parathion from the microencapsulated cake into soil and the relationship between available residue and wet weather were also investigated.

Methyl Parathion↗
PubMed1981

Comparison of hemoglobin A1c and hemoglobin A1 in diabetic patients.

Hemoglobin A1 (HbA1) and hemoglobin A1c (HbA1c) values were compared in 934 samples from 686 subjects with diabetes mellitus. Linear regression analysis revealed the two parameters to be highly related with HbA1 = 1.18 HbA1c + 1.67, and a correlation coefficient of 0.97. Samples with HbA1 greater than predicted from the measured HbA1c had been stored significantly longer (approximately 1 day) than other samples, suggesting that sample storage may slightly alter the relationship between these parameters. Serial HbA1 and HbA1c values in all 9 patients for whom data was available from at least 5 time points changed in parallel regardless of the time interval between sampling or the magnitude of the interval change of HbA1c and HbA1. These data indicate that the potentially simpler measurement of HbA1 gives results equivalent to HbA1c for clinical applications.

Adolescent↗