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Biomedical subjects

R Johnson

Publications and source records attributed to R Johnson.

At least 541 records · Page 30Linked to original sources
PubMed1983

Strain measurement in the medial collateral ligament of the human knee: an autopsy study.

A strain transducer was developed which employs a magnetic field sensing device to detect linear displacement. The transducer was attached to the medial collateral ligament (MCL) of human autopsy specimens, minimally influencing their physiologic behavior. A strain 'map' of the MCL as a function of knee flexion (full extension to 120 degrees) both with and without abduction force was obtained. Our investigation revealed consistent differences in the strain patterns between proximal, middle and distal segments of the anterior and posterior borders of the MCL. Anatomic variations in the pattern of collagen fibers within the MCL, interactions between posterior oblique capsular fibers and the MCL, and the skeletal configuration may account for these varied strain patterns.

Humans↗
PubMed1983

Misonidazole combined with large-fraction pelvic irradiation in the treatment of patients with advanced pelvic malignancies. Preliminary report of an ongoing RTOG phase I-II study.

Between October 1979 and January 1982, a total of 39 cases were entered on a nonrandomized phase I-II protocol for the evaluation of misonidazole combined with radiation in the treatment of patients with advanced pelvic malignancies of multiple gynecological and gastrointestinal origin. Patients were treated with pelvic irradiation using a dose of 1000 rad in one fraction every 4 weeks for a total of three treatments. Oral misonidazole at a dose of 4 g/m2, was administered 4-6 hours prior to the radiation treatment (total dose, 12 g/m2). Of the 39 patients entered, 25 have completed the three doses of radiation and have had at least one follow-up after the third treatment. Eight patients have had insufficient follow-up information for evaluation and five patients did not complete three doses of radiation but have follow-up. One patient was excluded from the study. Among the 30 patients with follow-up, there were four complete responses (13.3%) and seven partial responses (23.3%). Two patients showed no response, and 17 experienced progression of disease. Follow-up time ranged from 2 to 16 months. The most frequent toxicity in the study has been nausea and vomiting. There were eight cases of neurotoxicity reported: ototoxicity grade 1 (one patient), peripheral neuropathy grades 1 and 2 (six patients), and C.N.S. toxicity grade 2 (one patient). Toxicity from radiation was difficult to separate from the presenting symptomatology. In the 30 patients with follow-up information, eight cases of abdominal sequelae were seen with five of them major complications (perforation, obstruction, and abscess). Early information from the study indicates the following: The most frequent morbidity at this point is acute nausea and vomiting. This level of nausea is consistent with the protocol dose of misonidazole. From the evaluable patients, 5/30 (17%) have developed major bowel problems requiring surgery. At the time of this report, this protocol remains open for case accession.

Adolescent↗
PubMed1983

Management: theory.

Explore the source record for details and available documents.

Central Supply, Hospital↗
PubMed1983

Periportal localization of lorazepam glucuronidation in the isolated perfused rat liver.

The relative effects of pretreatment with allyl alcohol and carbon tetrachloride on oxidative and glucuronide metabolism of lorazepam have been compared in the isolated perfused rat liver. Livers from rats pretreated for 24 hr with allyl alcohol (1.8 ml/kg, 1:50 solution, to induce pericentral hepatic necrosis), carbon tetrachloride (0.8 mg/kg in corn oil, to induce perivenular hepatic necrosis), or vehicle were perfused with 20% rat blood, 80% Krebs bicarbonate buffer at 20 ml/min. After 300 micrograms of lorazepam had been added to the reservoir, perfusate concentrations of lorazepam were measured in the perfusate at timed intervals. After 180 min, lorazepam and lorazepam glucuronide were measured in perfusate, bile, and liver homogenate. Allyl alcohol and carbon tetrachloride lowered lorazepam clearance by 47% and 77%, respectively. Recovery of lorazepam glucuronide after 180 min was lowered by 35% by treatment with allyl alcohol and increased 73% by treatment with carbon tetrachloride. Glucuronide recovery permitted estimation of fractional glucuronide vs. nonglucuronide clearance. In control rats, glucuronide clearance accounted for 25% of total clearance. Allyl alcohol caused a 64% reduction in glucuronide clearance but only a 39% reduction in nonglucuronide clearance. In contrast, carbon tetrachloride caused a 60% reduction in glucuronide clearance but an 83% reduction in nonglucuronide clearance. The differences in ratios of the changes in glucuronide and nonglucuronide clearance provide further circumstantial evidence that is consistent with the hypothesis of predominant periportal localization of glucuronidation and pericentral localization of oxidative metabolism of lorazepam.

Allyl Compounds↗
PubMed1983

Immunization update.

Passive immunization is available against rabies, varicella, tetanus and hepatitis A and B. Active immunization is, in general, more efficacious with live attenuated viruses than with many of the bacterial vaccines. Toxoids, too, are very effective immunizing agents. Immunization usually starts at two months of age with DTP and oral poliovirus vaccine. For patients at high risk for secondary complications, influenza and pneumococcal immunizations are advisable. Hepatitis B vaccine is now available for persons at high risk because of their occupations.

Age Factors↗
PubMed1983

Hepatic production of erythropoietin in a phenylhydrazine-induced compensated hemolytic state in the rat.

The relative roles of the kidney and liver as a source of Ep in a fully compensated hemolytic state were investigated. A compensated hemolytic anemia was induced in rats by injections of PHZ over a 6-week period. Verification of a fully compensated hemolytic state was established by MCV, MCH, MCHC, BV, PV, CRCV, peripheral reticulocyte counts, and bone marrow counts. The kidneys and livers of the PHZ-injected rats were subjected to concurrent perfusion at weekly intervals over the treatment period and the perfusate assayed for Ep activity. The kidney was found to be the principal source of Ep during the earlier stages of the anemia and the liver became increasingly important as a source of Ep during the later stages as the anemia became progressively compensated. By the fifth and sixth weeks of treatment, when the anemia was fully compensated, the livers of the PHZ-treated rats were the principal source of Ep. During these last 2 weeks of treatment, the amount of Ep recovered from the renal effluents of PHZ-injected rats was no greater than that collected from the renal effluents of saline-injected rats. The data indicate that the liver is the primary, if not the only, source of the higher titers of Ep in the fully compensated hemolytic state induced in the rat by long-term PHZ treatment.

Anemia, Hemolytic↗
PubMed1983

Hemorrhagic shock.

Shock is a consequence of insufficient blood flow for adequate oxygenation at the cellular level. Early recognition of the signs permits prompt therapy to maintain the effective circulating volume before irreparable organ damage occurs. Classification of shock on the basis of percentage of blood loss is helpful in guiding initial management. Replacement of red blood cells may be required for acute blood loss of more than 25 percent of the patient's circulating volume. Adequate arterial PO2 is essential for maintaining cellular oxygenation.

Blood Circulation↗
PubMed1983

Integrating severely adaptive handicapped seventh-grade students into constructive relationships with nonhandicapped peers in science class.

The effects of cooperative and individualistic learning experiences were compared on interactions and relationships between severely adaptive handicapped (not adapting to regular classroom demands) and nonhandicapped seventh-grade students in science classes. We investigated the predictions that (a) requiring cooperation between the two groups of students would result in increased rejection of the severely adaptive handicapped students and (b) cooperation would promote increased interpersonal attraction regardless of the heterogeneity of the students. Forty-eight suburban junior-high-school, seventh-grade students (41 nonhandicapped, 9 severely adaptive handicapped) were assigned to conditions on a stratified random basis controlling for handicap, sex, and ability level. They participated in the study for 10 days, 55 minutes per day. Results indicated that cooperative learning procedures, compared with individualistic ones, promoted more interaction and interpersonal attraction between severely adaptive handicapped and nonhandicapped students.

Achievement↗
PubMed1983

Transfer of topically applied tetracycline in various vehicles.

Fifty hospitalized dermatology patients participated in a study to evaluate the transfer of topically applied tetracycline hydrochloride-containing fluorescent ointments, creams, lotions, and tinctures from various sites of application. Patients were examined with a Wood's lamp 24 hours after application to determine the sites and areas of transfer. The topically applied medications did not remain confined to sites of initial application. The anatomic sites of initial application determined the pattern of transfer. Certain patterns of transfer were characteristic among groups of patients and for specific patients. The vehicle of the topical preparation greatly influenced the extent and sites of transfer.

Administration, Topical↗