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Biomedical subjects

M C Johnson

Publications and source records attributed to M C Johnson.

157 records · Page 9Linked to original sources

Interaction of antibiotics and warfarin in pediatric cardiology patients.

Antibiotics are known to alter the anticoagulation induced by warfarin in adults, but little is known about this interaction in children. In a retrospective review of patients under the age of 21 years, we found that antibiotic therapy (89 courses of antibiotics in 23 patients) was associated with an increase in the mean international normalized ratio (INR) from 2.7 to 3.6. The change in INR correlated inversely with patient age. These data suggest that more intensive monitoring of the INR after starting antibiotics may help to mitigate excessive anticoagulation in children receiving warfarin.

Adolescent↗

Gps mutations in Chilean patients harboring growth hormone-secreting pituitary tumors.

Hypersecretion of GH is usually caused by a pituitary adenoma and about 40% of these tumors exhibit missense gsp mutations in Arg201 or Gln227 of the Gs, gene. We studied 20 pituitary tumors obtained from patients with GH hypersecretion. One tumor was resected from an 11 year-old boy with a 3 year history of accelerated growth, associated with increased concentrations of serum GH and IGF-I, which were not suppressed by glucose administration. The remaining 19 tumors were obtained from adult acromegalic patients, who had elevated baseline serum GH levels that did not show evidence of suppression after administration of glucose. The gsp mutations were studied by enzymatic digestion of the amplified PCR fragment of exon 8 (Arg201) and exon 9 (Gln227) with the enzymes NlaIII and NgoAIV, respectively. The tumors obtained from the boy and from nine of the 19 patients with acromegaly exhibited the gsp mutation R201H. None of the tumors had the Gln227 mutation. The gsp positive patients tended to be older, had smaller tumors, and had preoperative basal serum GH levels which were significantly lower (21 +/- 6 vs 56 +/- 16 microg/l, p<0.05) than the gsp negative patients. In this study, we documented the presence of a gsp mutation in Arg201 in a boy with gigantism and in approximately half of 19 Chilean adult patients with acromegaly, similar to other populations.

Adenoma↗

Persistence of fetal bovine serum proteins in human keratinocytes.

Cultured human keratinocytes are used for skin grafts, but their success is limited by late graft loss. Development of antibody to fetal bovine serum (FBS) protein used in culture media for in vitro keratinocyte growth has been identified. The persistence of FBS antigen in skin grafts is important in the induction of the immune response and the susceptibility of the keratinocytes to immune-mediated injury. The magnitude and longevity of FBS protein persistence on human keratinocytes was studied. Secondary passage human keratinocytes were grown in media supplemented with 5% FBS. The media was changed to one supplemented with pooled human AB serum, and the amount of FBS protein incorporated in the tissue was measured over the following 8 days by an ELISA reaction directed against FBS antigen. Incorporated FBS antigen decreased for the first 3 days to 31% of maximum. There was no further significant decrease for 5 days. Keratinocytes grown in alternative serum supplements (NuSerum [Collaborative Research Inc., Bedford, Mass.] and Serum Plus [Hazelton Research Products Inc., Lenexa, Kan.]), which contain reduced amounts of FBS, offered no significant reduction in FBS protein incorporation. This duration of antigen persistence would make human keratinocytes susceptible to cell destruction by immune response to FBS and may contribute to delayed loss of human keratinocyte grafts.

Animals↗

The Cooperative Cardiovascular Project in Oklahoma.

BACKGROUND AND OBJECTIVES: Acute myocardial infarction is the leading cause of death in the United States and a common cause for admission of Oklahoma Medicare beneficiaries. Based on guidelines for the management of acute myocardial infarction published by a joint committee of the American College of Cardiology and the American Heart Association, the Cooperative Cardiovascular Project was developed by the Health Care Financing Administration to measure performance on quality indicators that describe care provided to Medicare beneficiaries. The objective of the project is to use those performance measures to assist hospitals in the development of quality improvement efforts for acute myocardial infarction care. METHODS: Retrospective review was performed on the inpatient medical records of 3,436 patients from 102 hospitals in Oklahoma and a random national sample of 2,441 patients discharged with a principal diagnosis of acute myocardial infarction. RESULTS: The diagnosis of acute myocardial infarction was confirmed in 3,055 (89%) of the cases reviewed. For patients considered to be ideal candidates for an intervention, 62% received reperfusion therapy (thrombolytic or PTCA), 84% received aspirin during the hospitalization, 76% received aspirin at discharge, and 40% received beta-blockers at discharge. There were significant variations in performance between hospital peer groups in the use of reperfusion therapy, aspirin, beta-blockers, and smoking cessation counseling. CONCLUSIONS: Potentially life-saving treatments for Medicare patients hospitalized with an acute myocardial infarction are often underutilized. Improving quality of care for Medicare beneficiaries with acute myocardial infarction has been identified as a national priority.

Adrenergic beta-Antagonists↗