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Biomedical subjects

R E Johnson

Publications and source records attributed to R E Johnson.

At least 217 records · Page 12Linked to original sources
PubMed1985

Physicians' use of laboratory, radiology, and drugs in a prepaid group practice HMO.

Use by physicians of medical care resources to treat similar patients and morbidities has implications for the efficiency and effectiveness of medical care. This study examined the variation in primary care physicians' use of outpatient laboratory, radiology, drugs, and hospital admissions; the relationships among the uses of these resources by physicians; and uses of these resources by physicians over time. The setting was a large HMO and the physicians were internists (n = 30), pediatricians (n = 20), and obstetrician/gynecologists (n = 17). Resource use was a dollar rate for laboratory, radiology, and drug, and an admission rate per contact for the hospital. The physicians' use rates were derived from the computerized utilization record of a sample of HMO members for 1976-1978. Substantial variation occurred in the rates of use of each resource by physicians in each specialty. The relationships among the resource rates were similar for internists and pediatricians, and were somewhat stronger than expected clinically. There were also substantial consistencies over time in the levels of use of laboratory and drugs by internists and pediatricians. Findings suggest a potential for more judicious use of ambulatory care resources by primary care physicians in this setting.

Adolescent↗
PubMed1985

Intrapartum management of twin gestation.

Neonatal mortality and morbidity were analyzed in 362 pairs of twins delivered at Yale-New Haven Medical Center during a five-year period. Of the 154 (42.5%) pairs in vertex-vertex presentations, 125 (81.2%) were delivered vaginally. No difference in the occurrence of low five-minute Apgar scores was found in relation to the length of time interval between delivery of the twins. Of the 139 (38.4%) twins in vertex-nonvertex presentations, 99 (71.2%) were delivered vaginally. In the entire series, there was one case of significant birth trauma related to vaginal delivery of a nonvertex second twin. The one instance of neonatal death clearly related to birth asphyxia resulted after cesarean section. A protocol for the intrapartum management of twin gestations is presented based upon intrapartum fetal presentation and sonographically determined estimated fetal weight.

Apgar Score↗
PubMed1984

ADP binds similarly to rigor muscle myofibrils and to actomyosin-subfragment one.

The binding of Mg2+ ADP to both rabbit skeletal and bovine cardiac myofibrils has been studied at two different temperatures. In each case a single class of binding sites was observed with a binding constant very close to that reported for the analogous actomyosin-subfragment one but much weaker than that seen with the analogous myosin subfragment one alone. These findings are discussed in terms of the constraints on the myosin cross-bridges imposed by the regular array of thick and thin filaments found in myofibrils.

Adenosine Diphosphate↗
PubMed1984

Is routine cesarean section necessary for vertex-breech and vertex-transverse twin gestations?

Ninety-three vertex-breech and 42 vertex-transverse twin gestations were managed at Yale-New Haven Medical Center during a 5-year period. Antepartum diagnosis of twin gestation occurred in 93% of the cases, and diagnosis was made before delivery of the second twin in 97% of the cases. Seventy-two (78%) of the vertex-breech and 22 (53%) of the vertex-transverse twins were delivered vaginally. Breech extraction was used for delivery of 76 second twins. Below a birth weight of 1,500 gm, there were six neonatal deaths, four cases of documented intraventricular hemorrhage, and a 67% occurrence of depressed 5-minute Apgar scores. Above a birth weight of 1,500 gm, there were no cases of neonatal death or documented intraventricular hemorrhage and a 5% occurrence of moderately depressed 5-minute Apgar scores. Birth trauma occurred in a 3,420 gm second twin delivered by breech extraction. This infant suffered a greenstick fracture of the right clavicle and a nondisplaced fracture of the right humerus that was not associated with permanent residual injury. We think that, for birth weights greater than 1,500 gm, routine cesarean section for vertex-breech or vertex-transverse twin gestation may not be necessary.

Apgar Score↗
PubMed1984

The rat amygdaloid nucleus: a morphometric right-left study.

Our results indicate that Long-Evans male rats housed in standard conditions show no significant difference between the areas of sections of their left and right amygdalas. In contrast, the S1 strain maze-bright animals have a significantly greater right amygdala than left. Furthermore, the data indicate an overall increase in mean (R + L)/2 amygdala area from 6 to 400 days, except for a significant decrease in area from 26 to 90 days.

Aging↗
PubMed1984

Nucleotide-induced changes in the heat capacity of beef cardiac myosin.

The heat of reaction of ATP with beef cardiac myosin has been determined in a flow microcalorimeter at two different temperatures. The reaction heat obtained by extrapolation to infinite flow rate is interpreted to be the heat of formation of the steady-state set of myosin-nucleotide complexes. The large temperature dependence of this heat, an apparent change in heat capacity, could be caused by an isomerization between two myosin conformations. The enthalpies and heat capacities of binding of ADP, AMP, and pyrophosphate have also been measured and are discussed in terms of this model.

Adenosine Diphosphate↗
PubMed1984

Electroencephalographic and behavioral correlates of buprenorphine administration.

Male subjects on methadone maintenance who were residing in a research ward were switched to buprenorphine for 45 days. Physiologic measures, behavioral and subjective ratings of mood states, and an electroencephalogram (EEG) were obtained daily. Distinct changes in EEG activity paralleled physiologic and behavioral effects during the transition to buprenorphine. Similar physiologic effects and a reversal of EEG effects occurred when saline solution was substituted for buprenorphine. It is concluded that, consistent with its classification as a partial opiate agonist, buprenorphine may not substitute fully for methadone.

Adult↗
PubMed1984

Nuclear magnetic resonance imaging. The current state of a new diagnostic technology.

Nuclear magnetic resonance (NMR) imaging is a promising new technique in diagnostic medicine. Utilizing powerful magnets, radiofrequency transceivers, and computer imaging systems, NMR images reveal subtle yet striking information from an imaged slice segment of a living body. Its applications are numerous and growing rapidly. The central nervous system, the cardiovascular system, and the hepatobiliary tract have been examined with remarkable success. Imaging of musculoskeletal structures, renal studies, and intraabdominal studies have produced quality results. The unique sensitivity of NMR to neoplastic tissues may lead to its use for early cancer detection. Refinements of NMR instrumentation and computer software--and research into paramagnetic contrast agents--lead toward higher quality scans with wider applications. Hazards of NMR imaging are not yet clearly delineated. However, current NMR utilization parameters exclude certain high-risk groups (such as subjects with cardiac pacemakers) to ensure patient safety.

Magnetic Resonance Spectroscopy↗
PubMed1984

Physicians' attitudes toward an expanded role for pharmacists in an HMO.

The study examines the attitudes of physicians in a large HMO toward expanded activities for pharmacists and attempts to determine the physicians and their practice characteristics that account for these attitudes. The setting was the Oregon Region of the Kaiser-Permanente Medical Care Program. The data were obtained from a survey of the physicians serving the membership. The findings indicated that about two of every three physicians favored expanded activities for pharmacists. The specific activities most favored were those least threatening to physicians' roles. Their attitudes were most strongly related to whether they favored prescribing privileges for physician assistants and nurse practitioners. The physicians and their practice characteristics accounted for a small amount of the variation in physicians' attitudes. Large HMOs may be favorable settings for expanding the activities of pharmacists.

Attitude of Health Personnel↗
PubMed1984

Twin gestation. Antenatal diagnosis and perinatal outcome in 385 consecutive pregnancies.

Three hundred eighty-five gestations were managed in a perinatal center during a five-year interval. Twins were diagnosed antenatally in 90.4% and before delivery in 95.6% of cases. From this study, the value of hospitalization for bed rest after 28 weeks of gestation seems questionable, for 81% of the perinatal mortality in our study occurred prior to that time.

Female↗