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Biomedical subjects

R Johnson

Publications and source records attributed to R Johnson.

At least 289 records · Page 16Linked to original sources
PubMed1993

Comparative effects of erythropoietin with oral iron in peritoneal dialysis and hemodialysis patients.

The studies on the comparative efficacy of erythropoietin (rHuEPO) in chronic hemodialysis and peritoneal dialysis patients are scarce. We compared the use of rHuEPO in 74 stable patients on hemodialysis to 24 on chronic peritoneal dialysis. All patients were on oral iron supplement. In peritoneal dialysis patients hematocrit was 23.1% and 30.1%, rHuEPO dose 80.9 U/kg/week, while in hemodialysis patients hematocrit was 21.2% and 27.5%, and rHuEPO dose was 140.2 and 165.0 U/kg/week at commencement and after 6 months, respectively. Serum iron and transferrin saturation were unchanged in peritoneal dialysis patients, but decreased in hemodialysis patients with rHuEPO therapy. These findings suggest that rHuEPO is more effective in peritoneal dialysis patients than in hemodialysis patients receiving oral iron. The improved efficacy of rHuEPO in peritoneal dialysis may be due to decreased blood loss, subcutaneous administration, and/or better removal of inhibitors of erythropoiesis. Peritoneal dialysis may be more cost-effective and desirable than hemodialysis for rHuEPO-dependent or -resistant patients.

Administration, Oral↗
PubMed1993

Antihelicase action of DNA-binding anticancer agents: relationship to guanosine-cytidine intercalator binding.

DNA-binding antibiotics such as intercalators, narrow groove binders, and other substances modify duplex DNA, making it an altered substrate for DNA helicases. The intercalators daunorubicin, actinomycin D, echinomycin, and elsamicin, the narrow groove binders distamycin and mithramycin, and the plant toxin teniposide, each representing a different chemical class, block SV40 large T antigen DNA helicase action with IC50 values ranging from 4 x 10(-8) to 2 x 10(-6) M. A partially purified human HeLa cell DNA helicase is also potently blocked by daunorubicin, distamycin, and teniposide. Because eukaryotic cells contain helicases of varying abundance, specificity, and type, this site of action for DNA-binding antibiotics may help explain antibiotic potency and specificity for DNA or RNA inhibition. The antihelicase effect of the antibiotic-double-stranded DNA complex may be central to the anticancer activities of these substances. An additional interesting correlation is the antihelicase action of DNA-intercalating antibiotics and their DNA-binding preference for G-C base pair sites. The G-C base pair binding preference of the intercalating antibiotics may result from evolutionary selection because of the higher G-C binding stability, compared with A-T binding stability. The combination of the higher base pair stability at G-C regions and increased duplex DNA stability induced by intercalating antibiotic yields a total additive stability of the intercalator-G-C base pair complex that resists helicase action.

Animals↗
PubMed1993

Tolerability of prophylactic Lariam regimens.

Three hundred and fifty-nine US Marines participated in a randomized double-blind clinical trial to assess tolerance of two prophylactic mefloquine regimens [250 mg salt weekly (n = 157) or 250 mg daily for 3 days followed by 250 mg weekly (n = 46)] compared with 300 mg weekly chloroquine (n = 156) over a 12-week period. The study participants were seen daily for four days, then weekly for 11 weeks. On each visit, the subject answered two computerized questionnaires (a review of body systems and an evaluation of mood states), participated in a physician interview, and was administered medications under supervision. A random sample of each group was assigned to either pharmacokinetic sampling or two wear a wrist watch size computerized sleep monitor (actigraph). The frequencies of intercurrent illness and other concomitant medications were tabulated. End study mefloquine plasma levels were obtained on all study participants. The results obtained showed no compromise in function due to dizziness or incoordination in the mefloquine groups. Overall, both weekly mefloquine and loading dose mefloquine were well tolerated. Sleep disturbance and increased dream activity were detected in the mefloquine groups. Depressive feelings were noted in two to three times more individuals in the mefloquine groups than in the chloroquine group early in the course of the study, and resolved in the majority of subjects as tolerance developed. Steady state mefloquine plasma levels were attained rapidly with the loading dose regimen in four days versus seven weeks with weekly mefloquine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Nurse practitioner-patient discourse: uncovering the voice of nursing in primary care practice.

This study focused on nurse practitioner-patient conversations. The purpose was to uncover a process that might contribute to understanding the positive outcomes of nurse practitioner (NP) care. Transcripts from 24 audiotaped NP-patient conversations and three NP-researcher interviews, as well as 100 hours of field notes from observations, were analyzed using a combination of discourse and ethnographic analysis.

Adult↗
PubMed1993

Model for trauma outcomes management in patients with multiple trauma.

Critically injured patients with chest trauma generally sustain severe life-threatening injuries. Post-operative care tends to be complex, and all aspects of care from pre-hospital through rehabilitation must be coordinated and communicated to maximize patient outcomes. The Trauma Outcomes Management Model allows clinicians to assess, track, and analyze the relationship among interventions, outcomes, and the cost of care for each phase of the trauma care continuum. This article presents the design and utilization of trauma outcome guides in the Emergency and Critical Care departments.

Critical Care↗
PubMed1993

Comparison of physical health benefits utilization. Mental and physical health claimants, 1989 and 1990.

Research has indicated an association between mental health problems and physical illness, including higher physical health benefits utilization among persons with a mental health diagnosis. We hypothesized that mental health claimants will have higher covered health benefits and be more likely to make physical health claims than physical health claimants. The data for the study included all health benefits claims for 1989 and 1990. The results indicated that mental health claimants have higher total covered benefits and higher covered benefits in a number of diagnostic categories. In addition, the findings revealed a greater likelihood to make any health claim as well as a claim for several diagnostic categories among persons with a mental health diagnosis. The study indicates the need for coordination between mental health and physical health benefits cost management.

Adolescent↗
PubMed1992

Part exchange.

Explore the source record for details and available documents.

Organ Transplantation↗
PubMed1992

Salvage angioplasty: an alternative to high risk surgery for unstable angina?

This prospective, Human Subjects Committee and Ethics Committee approved investigation was performed to determine if coronary angioplasty (PTCA) might be a reasonable alternative revascularization method for unstable angina patients thought to be at high risk for operative (CABG) mortality. Between March 1990 and October 1991, thirty-four consecutive patients with medically refractory rest angina were deamed to have high risk of surgical mortality and underwent PTCA without surgical backup. Predicted operative mortality was calculated for each patient based upon the VA Surgical Risk Assessment model. Angioplasty of 52 vessels was attempted. Reduction in lumenal narrowing to < 50% and improved angiographic flow was obtained in 47 vessels. There were four complicating infarctions. One death occurred in the lab, and three patients with unsuccessful angioplasty died within 30 days of pump failure. Relief of angina occurred in 30/34. Thirty patients were discharged home. In follow-up from 1 to 12 months, there have been 2 late sudden deaths at 4 months and 9 months, 1 death from lung cancer; 4 patients have stable exertional angina; 2 are awaiting heart transplant but are pain free, and one patient who had PTCA during cardiogenic shock from acute myocardial infarction had elective coronary artery bypass surgery. There have been no late myocardial infarctions. The observed angioplasty 30-day mortality of 11.8% (95% confidence limit 1% to 22.6%) compares favorably with the predicted operative mortality of 23.8% for this group. This prospective but non-randomized series supports the concept that balloon angioplasty may be a reasonable alternative to surgical intervention in some patients with unstable angina and high risk for surgery. A prospective randomized trial is warranted.

Adult↗