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Biomedical subjects

D R Bell

Publications and source records attributed to D R Bell.

169 records · Page 10Linked to original sources
PubMedDate not supplied

Very low birth weight births at non-NICU hospitals: the role of sociodemographic, perinatal, and geographic factors.

PURPOSE: The purpose of this study was to assess the extent of variation in the percentage of very low birth weight (VLBW) infants born at perinatal Level 1 hospitals (no Neonatal Intensive Care Unit [NICU]) across California's nine geographic Perinatal regions. The role of sociodemographic, perinatal, and geographic factors was also assessed. METHODS: Multivariate analysis of California birth certificate files between 1989 and 1993, for 24,094 live-born infants weighing between 500 and 1499 gm, was conducted to identify factors associated with delivery at a Level 1 hospital. Analyses specific for race and ethnicity were also conducted for Hispanic, African American, and white cohorts. RESULTS: In the 5-year study period, 1989 through 1993, 10.5% (24,094) of all live-born VLBW infants were delivered in Level 1 hospitals. Significant variation across regions was evident, ranging from a regional low of 3.1% to a high of 24.3%. After controlling for multiple factors, the odds of delivering at a Level 1 hospital were decreased for African Americans and South East Asians and increased in Hispanic women as compared with white non-Hispanic women. For all women, less then adequate prenatal care, living in a 50% to 75% urban zip code, and living greater then 25 miles from the nearest NICU significantly increased the odds of VLBW delivery at a Level 1 hospital. For Hispanics, teen pregnancy and having two or more prior infant deaths increased the odds, whereas Medi-Cal as the payer source for delivery and two or more pregnancy complications decreased the odds of a Level 1 VLBW delivery. After taking these factors into account, when compared with Los Angeles, the odds of inappropriate delivery site ranged from 0.37 to 2.75 across California's nine geographic perinatal regions. Of this variation, 78% could be accounted for by the percentage of total births that delivered at a region's Level 1 hospitals. CONCLUSION: The overall state average of 10.5% deliveries of VLBW at Level 1 hospitals, although close to the 10% national objective for the year 2000, did not indicate the wide variation seen across California's nine geographic regions. Risk-adjusted regional differences in the likelihood of inappropriate delivery site for the high-risk VLBW infants suggest that reaching the Healthy People 2000 objective will require further strengthening of California's perinatal regional networks, especially in those regions where a high percentage of total births deliver at Level 1 hospitals.

California↗
PubMedDate not supplied

Profiles of velocity in coronary arteries of dogs indicate lower shear rate along inner arterial curvature.

Multiple-range, gate-pulsed Doppler velocimetry was used to examine the velocity profile within the lumen of the left circumflex and left anterior descending coronary arteries of 10 anesthetized, open-chest dogs at rest and after administration of propranolol and intracoronary adenosine. The peak diastolic and mean profiles of velocity were skewed away from the inner walls of the vessels (p less than 0.01). The extent of skewness was not affected by propranolol or adenosine. The shear rates were significantly lower along the inner wall in comparison to the outer wall under all conditions in both the left circumflex and the left anterior descending coronary arteries (p less than 0.017). Irrespective of the levels of flow, therefore, the velocity profiles were skewed away from the inner wall of the coronary arteries. Consequently, the shear rates were lower along the inner walls of the coronary arteries.

Animals↗
PubMedDate not supplied

Increased resistance and impaired maximal vasodilation in normotensive vascular beds of rats with coarctation hypertension.

To study the resistance of normotensive vascular beds in coarctation hypertension, we measured perfusion pressures of pump-perfused (blood), innervated, isolated hindlimbs of 12 rats (Group A) with 4 weeks of hypertension due to partial contriction of the abdominal aorta above the renal arteries, and of three control groups: 11 normotensive rats (Group B) with aorta sham-constricted, nine normotensive rats (Group C) with slight (5%) hindquarters atrophy due to partial constriction of the abdominal aorta below the renal arteries, and six rats with two-kidney, one clip Goldblatt hypertension (Group D). After aortic constriction, measured femoral arterial pressures in Group A rats remained normotensive. In hypertensive rats of Groups A and D, compared to normotensive Group B or C rats, hindlimb pressure-flow curves were displaced toward the pressure axis (p < 0.05). Compared to normotensive rats, drop in hindlimb resistance after acute local nerve section was increased in rats with coarctation hypertension. Residual resistance after maximal vasodilation with intraarterial sodium nitroprusside remained elevated in hypertensive rats of Groups A and D (p < 0.05), as compared to normotensive Group B or C rats; compared to Group B rats, this residual resistance in the coarcted rats of Group A was increased by 9%. Thus, in normotensive vascular beds of rats with chronic hypertension caused by aortic coarctation, resistance is elevated. The neurogenic component contributes to this high resistance, and structural vascular changes, indicated by impaired maximal vasodilation, may also contribute to the elevated resistance. It is most unlikely that these resistance changes are attributable to elevated hindlimb intravascular pressures.

Animals↗
PubMedDate not supplied

Glottic squamous cell carcinoma (T(2)): a retrospective study.

Seventy-three patients with T(2) glottic squamous cell carcinoma were treated primarily with a full course of cobalt radiotherapy. This series covered the time period between 1960 and 1972 and, therefore, all patients were eligible for five-year follow-up. Only seven patients, or 9.6%, have died of or with recurrent laryngeal carcinoma. Fourteen patients suffered recurrence of disease after radiotherapy and 12 of this group underwent salvage surgery. Surgery was successful in controlling recurrent disease in 7 of 12 patients, 3 of whom are still alive and free of disease. Forty-two patients, or 57.5%, are alive and free of disease five or more years after diagnosis. Twenty-four patients died without evidence of disease; 11 lived more than five years and 13 died in less than five years. On the basis of these findings, we feel that the best treatment for T(2) glottic squamous cell carcinoma is a full course of cobalt radiotherapy followed, when necessary, by salvage surgery.

Adult↗
PubMedDate not supplied

Permeability changes following ischemia-reperfusion injury in the rabbit hindlimb.

Changes in permeability following ischemia-reperfusion injury were assessed in the intact rabbit hindlimb by measuring the transvascular clearance of 125I-labeled rabbit serum albumin. Ischemia was induced for periods of 1 or 2 hours by use of a pneumatic tourniquet inflated to 300 mmHg. Following ischemia, the limb was reperfused for 1, 2, or 3 hours. The albumin clearance in the gastrocnemius muscle of control rabbits was 5.1 +/- 0.7 (mean +/- SEM) microliters/hr/g dry weight. Following 1 hour of ischemia and reperfusion, muscle albumin clearance rose to 71.4 +/- 26 microliters/hr/g dry weight which was not significantly different from those animals that underwent 2 hours of ischemia. Muscle albumin clearance continued to be elevated following 2 hours of reperfusion; however, it returned toward control levels after 3 hours of reperfusion. These data suggest there is a transient increase in albumin permeability following ischemia-reperfusion injury in skeletal muscle.

Animals↗
PubMedDate not supplied

Superior vena caval obstruction: a 10-year experience.

One hundred and fifty-nine patients with symptoms of superior vena caval obstruction who presented to two major hospitals over a 10-year period, from 1970 to 1979, were reviewed. Lung cancer was the most common histological diagnosis. The most common symptoms were dyspnoea and a feeling of fullness in the head. The most common physical findings were dilatation of the neck or chest wall veins, or oedema of the face and arms. Superior mediastinal widening was the most common radiological abnormality. No significant morbidity was associated with any diagnostic procedure. Only patients with lymphoma had a significantly longer survival period, both from the diagnosis of the disease, and from the onset of the symptoms of superior vena caval obstruction. There is no evidence that superior vena caval obstruction is an absolute medical emergency. Appropriate diagnostic steps should be undertaken to establish the histological diagnosis. The prognosis for some tumour types may be improved by combined modality therapy (chemotherapy plus radiotherapy).

Australia↗