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Biomedical subjects

R Johnston

Publications and source records attributed to R Johnston.

At least 91 records · Page 5Linked to original sources
PubMed1986

Myasthenia gravis after allogeneic bone marrow transplantation: relationship to chronic graft-versus-host disease.

Three patients with chronic graft-versus-host disease (GVHD) developed myasthenia gravis (MG) 762 to 1,180 days after allogeneic bone marrow transplantation. Symptoms of MG were observed after taper or discontinuation of immunosuppressive treatment of chronic GVHD. All patients developed antibodies to acetylcholine receptor, and one had antibody formation to striated muscle. One patient died of complications of treatment of MG. The severity of disease underscores the importance of the differential diagnosis and the need for prompt therapy of this late complication after human bone marrow transplantation.

Acetylcholine↗
PubMed1985

Ultrastructural features of minute chromosomes in a methotrexate-resistant mouse 3T3 cell line.

The Miller spreading procedure was applied to mouse metaphase spreads of methotrexate-resistant 3T3 cells that contain large numbers of minute chromosomes and dihydrofolate reductase genes. There is substantial variation in both size and numbers of minutes in individual cells, the smallest of which (estimated as 5 X 10(3) kilobase pairs) would be undetected by standard light microscopic analyses. Minute chromosomes are composed of nucleosomal chromatin, which is organized into typical higher order fibers that are folded to form rosette-like structures characteristic of normal chromosome organization. There is no evidence that the DNA in minutes is linear. Minutes exist singly and in pairs, and members of a pair are connected by higher order chromatin fibers, suggesting that they are topologically interlocked. They are often closely apposed to chromosomal telomeres or arms, a configuration that may be involved in their distribution at mitosis. In addition to typical minutes, which do not possess kinetochores, a small marker chromosome possessing all of the features of a centromere region is present in parental and resistant cells. An unusual feature of this cell line is the retention of resistance, minute chromosomes, and amplified dihydrofolate reductase genes; most methotrexate-resistant mouse cell lines with minute chromosomes lose these properties when grown in the absence of methotrexate.

Animals↗
PubMed1985

Sheath impaction as a cause of defective intra-aortic balloon pump action in man.

Intra-aortic balloon counterpulsation became ineffective in a 63 inch (160 cm) 14 year old girl while console operation proceeded almost normally. The problem was simulated in a hydraulic model of the aorta and could be reproduced when the proximal end of the balloon engaged in the introducing sheath. Measurements of the balloon catheter and sheath against the patient indicated that such engagement had occurred during counterpulsation. The findings provide an explanation for apparent catheter 'kinkage' in other patients where there was difficulty running the Kontron console in automatic mode. Problems are preventable by total or partial withdrawal of the inserting sheath.

Adolescent↗
PubMed1985

Oligodendroglioma and cerebral cavernous angioma. Case report.

The authors report a case of frontal lobe oligodendroglioma associated with a cavernous angioma. The patient presented with signs and symptoms of raised intracranial pressure. Computerized tomography with contrast enhancement failed to detect the vascular component. The clinical and pathological significance of the presence of this vascular malformation in an oligodendroglioma is discussed.

Adult↗
PubMed1985

Out-of-plan use by Medicare enrollees in a risk-sharing health maintenance organization.

In this study, we analyzed the cost and volume effects of a waiver that eliminated lock-in restrictions on out-of-plan use in a health maintenance organization (HMO) with a Medicare risk-sharing contract. We compared out-of-plan cost and number of claims during a 15-month base line period when the lock-in was in effect, with a 24-month waiver period when the lock-in was removed. The results demonstrate that average per capita cost and claims increased significantly for both Medicare Part A (hospital insurance) and Part B (supplementary medical insurance) out-of-plan services during the waiver. Self-referred out-of-plan use normally prohibited by lock-in, accounted for 20 percent of all out-of-plan costs during the waiver and 57 percent of the increase in out-of-plan costs from the lock-in to the waiver. The combination of risk-sharing and lock-in provisions holds promise as a method for reducing expenditures for the Medicare program.

Costs and Cost Analysis↗
PubMed1982

Third-generation beta-lactam antibiotics for treatment of orthopedic infections.

Third-generation beta-lactam antibiotics are effective against a wider range of microorganisms than are older antibiotics. Cefotaxime, moxalactam, cefoperazone, ceftizoxime, ceftazidime, cefsulodin, and ceftriaxone were used to treat 102 patients hospitalized with orthopedic infections. Sensitivity of the pathogens to the antibiotic used was established in all cases. Patients allergic to penicillin were given either moxalactam or ceftazidime. Pathogens were eradicated in all but six instances, five of which were Pseudomonas aeruginosa. Four of these developed resistance during therapy. Only three patients had clinical responses that were less than satisfactory. No serious adverse reaction occurred, and no allergic reactions developed. This new class of antibiotics is thus safe and effective as the sole therapeutic agent for many orthopedic infections, including those that require long periods of treatment.

Adolescent↗
PubMed1981

Policy choices available in genetic counseling for people at-risk for Huntington's disease.

Staff on 94 wards in 78 Veterans Administration Medical Centers caring for Huntington's disease patients were interviewed by telephone to determine their policy, practice, and attitude regarding counseling HD families. Considerable variability among wards within a given hospital and among different hospital was reported. Presentation of genetic information was found to be significantly associated by statistical tests with existence of some kind of ward counseling policy, treatment on a neurology ward, active seeking-out of relatives, construction of pedigree charts, and specific staff designated to provide such counseling. Genetic discussions with families of HD patients and at-risk kindreds raise some sensitive ethical questions, notably the vigorous denial of disease in these families, the high suicide rate of those at-risk, and consideration of patients' rights regarding privacy of medical data. A consistent genetic information-giving policy, at least among wards of each hospital and possibly among all hospitals within a large hospital system, is recommended as a logical and desirable goal.

Genetic Counseling↗
PubMed1980

Psychotropic drugs and depressive syndrome in schizophrenia.

Lifelong records of schizophrenic illnesses were examined in order to compare the occurrence and characteristics of depressive syndrome in the pre-phenothiazine era and with neuroleptic treatments. It was found that a depressive syndrome similar to endogenous depressive psychosis develops spontaneously and independently of neuroleptic medication. The relationship of this endogenous syndome to the postpsychotic depression of other origin is discussed.

Adult↗
PubMed1979

Effect of high-energy feedings on low birthweight infants.

A comparison of the effect of 100.5 kJ/30 mL (24 kcal/30 mL) feedings with that of 84 kJ/30 mL (20 kcal/30 mL) feedings on infants with a birthweight of 1500 g or less was made. No consistent benefits in growth occurred and there was a tendency for an increase in complications in infants fed the 100.5 kJ/30 mL milk. Hence the higher-energy feeding cannot be recommended as the routine feeding for low birthweight infants.

Body Weight↗
PubMed1979

Teratoma in horseshoe kidneys.

Renal tumors are uncommon, but they are significantly increased in horseshoe kidneys. Although nephroblastomas frequently occur in horseshoe kidneys of children, no teratoma has been observed in the past. A teratoma in the horseshoe kidney of a child with unusual congenital anomalies is described.

Abnormalities, Multiple↗