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Biomedical subjects

R E Johnson

Publications and source records attributed to R E Johnson.

At least 271 records · Page 15Linked to original sources
PubMed1981

Bulimia.

Bulimia, also known as compulsive eating, has recently been recognized as a disease. Although bulimia is thought to be common, especially among young women, little is known about it. Theorized causes are primary neurologic dysfunction (epileptiform), disturbance in the appetite/satiety center of the hypothalamus, learned abnormal behavior or unsuppressed oral drive. Diagnosis rests primarily on the symptoms. Possible treatment measures include phenytoin, aversion therapy, psychotherapy and self-help groups.

Adolescent↗
PubMed1980

Determination of prognostic factors and their influence on therapeutic results in patients with Ewing's sarcoma.

We have analyzed the results of treatment of 117 patients with Ewing's sarcoma admitted to the National Cancer Institute since 1964. All patients received local irradiation to the primary site and a series of progressively more intensive systemic chemotherapy regimens using drugs known to be active as single agents in this disease. Four protocols were employed with varying numbers of patients in each treatment group. Initially, there appeared to be a difference among treatment groups with regard to disease-free survival (overall P = .06), with the later regimens having more favorable outcomes. We then undertook a statistical analysis of the influence of five pretreatment variables--age, sex, site of primary disease, serum lactic acid dehydrogenase (LDH), and metastatic status--on disease-free survival. Of these five factors, important indicators of favorable prognosis for the entire group (and for each of the treatment subgroups) were a distal site of primary disease, normal serum lactic acid dehydrogenase (LDH) level at presentation, and the absence of metastatic disease at the time of presentation. When we examined treatment results with respect to these prognostic factors, we found that the subgroups treated with the more agressive regimens contained higher proportions of patients with favorable prognostic factors. After adjustment for differences in composition of treatment groups with respect to prognostic factors, the apparent difference in disease-free survival vanished (P = .62). These results indicate that in the case of Ewing's sarcoma, prognostic factors must be carefully considered in the design of treatment protocols and the subsequent analysis of end results.

Age Factors↗
PubMed1980

The SENIC sampling process: design for choosing hospitals and patients and results of sample selection.

To achieve its primary objectives, the Study on the Efficacy of Nosocomial Infection Control (SENIC Project) focused its attention on a target population of patients referred to as SENIC-eligible admissions in a target population of hospitals referred to as the "SENIC Universe." SENIC thus required a design for sampling hospitals and patients within these hospitals and a valid procedure for projecting sample results to the target population. This paper presents the details of the sampling design used, describes the actual process of selecting hospitals and patients for the surveys, explains the procedure used to project sample results to the target population, and examines the possibility of bias in the design and hospital selection process. As with most large-scale sample surveys, the design and sample selection processes for the surveys in Phases II and III of SENIC were complicated by incomplete frame, nonresponse and measurement problems. Nevertheless, adjustments to reduce the effects of some of these problems have been made through the development of a valid procedure for projecting sample results to the target population, and it appears unlikely that practically important nonsampling biases will result from the estimation procedures applied to this sample of hospitals.

Cross Infection↗
PubMed1980

Recent changes in the incidence of duodenal and gastric ulcer.

The incidence of duodenal and gastric ulcer was examined in a Health Maintenance Organization with over 200,000 members. Hospitalization data were available from 1966 through 1975, and outpatient data from 1967 through 1973. Outpatient episodes of duodenal ulcer declined from 21.0 +/- 3.6 episodes per 1000 male person years (PY) in 1967 to 6.6 +/- 1.5 per 1000 male PY in 1973, and from 9.4 +/- 2.4 episodes per 1000 female PY in 1967 to 4.1 +/- 0.8 per 1000 female PY in 1973. Similar declines were observed in the hospitalization data. There were slight declines in gastric ulcer rates, but these were not significant except for a decrease in male gastric ulcer hospitalizations. The decrease in duodenal ulcer incidence has no readily apparent explanation.

Adolescent↗
PubMed1979

Binding of reduced and oxidized nicotinamide adenine dinucleotide to pig heart supernatant malate dehydrogenase.

The association reactions of NADH and NAD+ with dimeric pig heart supernatant malate dehydrogenase (s-MDH) have been measured at pH 6 and 8 by calorimetric and fluorescence methods, and the thermodynamic parameters describing these reactions have been evaluated. Coenzyme binding is associated with the uptake of 0.55 mol of H+/mol of NADH at pH 8 and 0.19 mol of H+ at pH 6. No significant effect of NAD+ binding on proton binding was observed. Increase in ionic strength strongly affects the free energies of binding of NAD+ and NADH. No cooperativity was observed in the enthalpy or free energy changes for binding of NAD+ or NADH. The differences in free energy of binding of NAD+ and NADH and the effect of pH on binding of NADH are entropy based. These effects are interpreted as reflecting a small number of interactions within the active site that are predominantly ionic.

Animals↗
PubMed1979

Lifetimes and NADH quenching of tryptophan fluorescence in pig heart cytoplasmic malate dehydrogenase.

The time-resolved and steady state fluorescence properties were measured for pig heart cytoplasmic malate dehydrogenase at pH 6.0 and 8.0. The fluorescence decay can be described by two rate processes, according to the functions: I(t) = 0.7e(-t/1.0) + 0.3e(-t/4.4) for the free enzyme and I(t) = 0.7e(-t/0.8) + 0.3e(-t/2.0 for the enzyme . NADH complex. Quenching by NADH of the tryptophan fluorescence is linear. The only effect of pH is to change the association constant for NADH binding; the fluorescence of the free enzyme and the fluorescence quenching by NADH, I-, and acrylamide are unaffected by pH. Thus there are no changes in conformation of the free enzyme or of the NADH complex over the range of pH 6 to 8.

Animals↗
PubMed1979

Thermodynamics of glucagon aggregation.

Heats of dilution of concentrated glucagon solutions have been measured calorimetrically at 10 and 25 degrees C in 0.2 M potassium phosphate buffer of pH 10.6. Analysis of the data in terms of a monomer-trimer equilibrium gives the following thermodynamic parameters for the association reaction at 25 degrees C: delta G degrees = 7.34 kcal/mol of trimer, delta H degrees = -31.2 kcal/mol, deltaS degrees = -80 cal/(K mol), deltaCp = 430 cal/(K mol). The sensitivity of heat of dilution data to the association constant and stoichiometry of the reaction is discussed.

Calorimetry↗
PubMed1979

A comparison between combination chemotherapy and total body irradiation plus combination chemotherapy in non-Hodgkin's lymphoma.

Thirty-nine untreated patients with either lymphocytic or nodular mixed/nodular histiocytic non-Hodgkin's lymphoma, stage II--IV, were randomized to treatment with total body irradiation (TBI), 100 rads in 10 fractions over 12 days, plus combination chemotherapy with either cyclophosphamide, vincristine and prednisone (CVP) or cyclophosphamide, vincristine, procarbazine and prednisone (C-MOPP) or to treatment with combination chemotherapy (CVP or C-MOPP) alone. Remission rate and duration was comparable for both treatment groups; thus the use of both treatment modalities ab initio provides no therapeutic advantage.

Adult↗
PubMed1979

Acute nonlymphocytic leukemia and acute myeloproliferative syndrome following radiation therapy for non-Hodgkin's lymphoma and chronic lymphocytic leukemia: clinical studies.

Seven cases of acute nonlymphocytic leukemia (ANLL) and one case of a malignant myeloproliferative syndrome have been seen after extensive radiation therapy for non-Hodgkin's lymphoma or chronic lymphocytic leukemia. A myeloproliferative syndrome with abnormalities in granulocytic, erythrocytic, and thrombocytic cell lines was present in all patients and in seven patients preceded ANLL by 2--18 months. The median time to the development of ANLL after primary disease therapy was 61 months (33--98 range). The leukemia was extremely refractory to therapy and median survival after diagnosis of ANLL was two months (range 0--9 months). Leukemia was seen only in those patients who received multiple courses and multiple techniques of radiation therapy.

Adult↗
PubMed1979

Flagellar hydrodynamics. A comparison between resistive-force theory and slender-body theory.

This paper investigates the accuracy of the resistive-force theory (Gray and Hancock method) which is commonly used for hydrodynamic analysis of swimming flagella. We made a comparison between the forces, bending moments, and shear moments calculated by resistive-force theory and by the more accurate slender-body theory for large-amplitude, planar wave forms computed for a flagellar model. By making an upward empirical adjustment, by about 35%, of the classical drag coefficient values used in the resistive-force theory calculations, we obtained good agreement between the distributions of the forces and moments along the length of the flagellum predicted by the two methods when the flagellum has no cell body attached. After this adjustment, we found the rate of energy expenditure calculated by the two methods for the few typical test cases to be almost identical. The resistive-force theory is thus completely satisfactory for use in analysis of mechanisms for the control of flagellar bending, at the current level of sophistication of this analysis. We also examined the effects of the presence of a cell body attached to one end of the flagellum, which modifies the flow field experienced by the flagellum. This interaction, which is not considered in resistive-force theory, is probably insignificant for small cell bodies, such as the heads of simple spermatozoa, but for larger cell bodies, or cell bodies that have large-amplitude motions transverse to the swimming direction, use of slender-body theory is required for accurate analysis.

Flagella↗