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Biomedical subjects

D Bell

Publications and source records attributed to D Bell.

At least 181 records · Page 10Linked to original sources
PubMed1987

Characterization in vitro and in vivo of progressively adriamycin-resistant B16-BL6 mouse melanoma cells.

Adriamycin (ADR)-resistant sublines of B16-BL6 mouse melanoma selected by exposure to increasing concentrations of ADR were characterized in vitro for growth properties and in vivo for tumorigenicity and pulmonary metastases. The progressively resistant sublines adapted to grow in the presence of 0.025, 0.05, 0.1, and 0.25 microgram/ml ADR in monolayer culture were found to be 5-, 10-, 20-, and 40-fold ADR-resistant, respectively, compared to the parental sensitive cells, using a soft-agar colony assay and continuous ADR treatment for 7 days. The doubling time in monolayer culture of the parent sensitive and progressively ADR-resistant sublines of B16-BL6 melanoma cells was approximately 16-18 h. Although the colony-forming efficiency in soft agar of parental sensitive cells was only 0.5-4%, the 5-, 10-, 20-, and 40-fold ADR-resistant sublines had colony-forming efficiencies of 15, 20, 30, and 77%, respectively. Tumorigenicity in C57BL/6 mice of progressively ADR-resistant sublines was similar to parental sensitive cells following s.c. and i.p. implantation of 10(5)-10(6) tumor cells. Experimental pulmonary metastases were significantly lower in ADR-resistant sublines with progressive resistance. Additionally, unlike the parental sensitive and 5-fold ADR-resistant B16-BL6 cells, the 10-, 20-, and 40-fold ADR-resistant sublines were spontaneously nonmetastatic. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunochemical detection of P-glycoprotein revealed the presence of a Mr 170,000 plasma membrane glycoprotein in the 40-fold ADR-resistant subline and its counterpart maintained for 1 year in ADR-free medium. Results from this study suggest that progressively ADR-resistant B16-BL6 mouse melanoma cells selected in vitro demonstrate a marked increase in colony formation in soft agar and a decrease in the ability to produce pulmonary metastases, without alterations in tumorigenicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1987

Fetus with asymmetric parietal encephalocele, and hydrops secondary to laryngeal atresia.

We describe a fetus with an asymmetric, nonmidline, parietal encephalocele that appeared to result from "expulsion" through the center of the membranous bone; the fetus also had laryngeal atresia, which caused pulmonary overdistension (fetal Valsalva maneuver) with consequent hydrops fetalis. A common cause and clear pathogenetic relationship between these anomalies is not apparent.

Abnormalities, Multiple↗
PubMed1987

Left ventricular preparation with an extrathoracically adjustable balloon occluder.

We developed a hydraulic occluder that could be adjusted percutaneously through a subcutaneous reservoir. Because of the potentially high pressures that may occur in preparing patients with transposition of the great vessels for an atrial switch procedure, the band on that hydrauler was modified to withstand arterial pressure and was subjected to studies involving banding of the aorta. Data indicate the suitability of this hydraulic occluder to withstand and maintain pressure in the systemic circulation.

Animals↗
PubMed1987

The acute inflammatory response to myocardial infarction: imaging with indium-111 labelled autologous neutrophils.

The uptake of indium-111 labelled neutrophils was examined in 30 patients with acute myocardial infarction by planar imaging and single photon emission computed tomography. The time from venepuncture to reinjection of the autologous labelled neutrophils was less than 2.5 hours and imaging was carried out 24 hours later. Twenty three patients had a positive uptake of neutrophils in the myocardium and imaging was improved by single photon emission computed tomography. There was a significant difference between the intervals from the onset of chest pain to injection of labelled neutrophils between patients with positive and negative images; early reinjection was more likely to produce a positive image. Indeed, all nine patients reinjected within 18 hours of the onset of symptoms had positive images. The results suggest that the stimulus for activation and migration of neutrophils is transient; this is an important factor if neutrophil release products play a role in cell damage after coronary occlusion.

Acute Disease↗
PubMed1987

Carbonated drinks, thiamine deficiency and right ventricular failure.

A 69 year old male presented with clinical features of right ventricular failure. A dilated poorly contracting right ventricle was confirmed by echocardiography and radionuclide ventriculography, with subsequent improvement following thiamine replacement. Wet beriberi is a result of thiamine deficiency and is uncommon in Europe and North America except in association with chronic alcohol abuse. We report a patient with beriberi presenting unusually with severe right-sided cardiac failure, with documented impairment of right ventricular function, which improved with thiamine replacement. His dietary intake of thiamine was low because of excess intake of carbonated drinks and carbohydrates.

Aged↗
PubMed1987

Home care in New York City: providers, payers, and clients.

Estimates based on 1980 data indicate that almost two-thirds of the disabled elderly in New York City receive care only from informal sources. Another one-fifth use a combination of informal and formal sources of care. Thus, only about 15 percent are exclusively dependent on various agencies and programs that constitute the formal home care system. Over 200 organizations in 1986 offered some form of home care service in New York City. Among these were at least 100 proprietary businesses, 61 nonprofit personal care agencies, and 36 nonprofit certified home health agencies. In 1984, 166,739 different New York City residents received home care services provided by the four largest types of formal providers of care: certified home health agencies; Long Term Home Health Care Programs; Human Resources Administration home attendant agencies and homemaker/housekeeper agencies; and Department for Aging homemaker/housekeeper programs. While women age 65 and older living alone are the largest client group for home care services, persons below age 65 account for approximately one-fourth of program caseloads of the four major home care providers in New York City. An estimate of one-day home care use in 1984 shows that the four major types of providers served 59,554 persons with total annual expenditures of $499.3 million, while nursing homes cared for 36,072 persons with annual expenditures of almost $1.4 billion. It is thus evident that more people are receiving organized, extended care at home on a given day in New York City than in nursing homes. Medicaid, the major payer for home care in New York City, spent $412.4 million on home care services in 1984, accounting for 82.6 percent of total publicly funded expenditures for home care services. Of this amount, 89 percent was for personal care services provided through the Human Resources Administration's personal care program. More details on home care in New York City follow, along with a discussion of policy perspectives surrounding the provision of and payment for home care services in the future.

Aged↗
PubMed1987

Recurrent cerebral ischemia and mitral valve vegetation in a patient with antiphospholipid antibodies.

A 37-year-old woman presented with a history of acute loss of vision in her left eye and a history of recurrent transient ischemic attacks. Subsequent investigations revealed a prolonged PTT. The lupus anticoagulant and anticardiolipin antibodies (aCL) were identified in her serum. A cardiac murmur was heard and echocardiography demonstrated a mass on the mitral valve. Extensive studies for infection were negative. Cardioembolic phenomena were considered a possible cause of her cerebral ischemic events. The occurrence of nonbacterial endocardial verrucae is well described in systemic lupus erythematosus. The pathogenesis of this lesion remains speculative, however, its occurrence in our patient, with a lupus anticoagulant and aCL suggests a possible association. The clinical manifestations of thrombosis in patients with antiphospholipid antibodies are varied, and may include the development of thrombotic endocardial lesions.

Adult↗
PubMed1987

The use of captopril and captopril plus frusemide as antihypertensive agents in non-insulin dependent diabetes.

After all previous antihypertensive treatment had been stopped, blood pressure and glucose tolerance were measured in 16 hypertensive non-insulin treated diabetics before and again six weeks after treatment with captopril, an angiotensin-converting enzyme inhibitor. Supine blood pressure fell from 184 +/- 4.1/103 +/- 2.6 to 165 +/- 5.2/88 +/- 2.1 mmHg (P less than 0.001) and erect from 179 +/- 5.2/102 +/- 3.2 to 158 +/- 5.6/87 +/- 2.6 mmHg (P less than 0.005). The area under the oral glucose tolerance curve fell from 2313.6 +/- 154 to 2192.8 +/- 146 mmol/min/l (P less than 0.02). There was no change in plasma insulin, total glycosylated haemoglobin or fructosamine. Four patients who failed to show lowering of supine diastolic pressure below 95 mmHg were additionally given oral frusemide with further improvement in blood pressure and no alteration in carbohydrate intolerance. It was concluded that captopril alone is usually an effective antihypertensive agent in non-insulin dependent diabetes with the addition of frusemide benefiting resistant cases. Glucose intolerance did not worsen with either captopril alone or captopril plus frusemide.

Blood Glucose↗
PubMed1986

Birth asphyxia, trauma, and mortality in twins: has cesarean section improved outcome?

The outcome of two populations of twins delivered at the same hospital, numbering 554 in 1963 to 1972 and 614 in 1978 to 1984, was reviewed to determine the factors contributing to depression at birth, trauma, and mortality in each period. The cesarean section rate had increased from 3% in the early period to 51% in the later period, with 92% of the later cases in which the first twin presented abnormally being delivered by cesarean section. Among infants of greater than 28 weeks' gestation the incidence of severe depression at birth was not reduced with the increased cesarean rate, remaining at 2% in both populations; none developed encephalopathy or died as a result of birth asphyxia or trauma. Neonatal mortality was markedly reduced in the second period, primarily because of a reduction in deaths resulting from respiratory distress syndrome. It is not possible to show that the marked increase in the rate of cesarean delivery has improved the condition of twin infants at birth.

Asphyxia Neonatorum↗
PubMed1986

The preparation and in vivo behaviour of 111In-oxine labelled neutrophils separated from whole blood using mono-poly resolving medium.

using a single step separation procedure, we have developed a method for labelling human neutrophils with 111In-oxine. This method allows a rapid separation of neutrophils from whole blood, with negligible mononuclear or red cell contamination. Preliminary studies using 111In-labelled neutrophils show minimal lung retention and early accumulation in the spleen consistent with viable cells. In addition, focal accumulation of 111In has been imaged in patients with localized inflammation or sepsis.

Cell Separation↗
PubMed1986

The effect of captopril on blood pressure and glucose tolerance in hypertensive non-insulin dependent diabetics.

Thirteen hypetensive non-insulin dependent diabetics (9 male, 4 female, mean age 61.6 +/- 6 years) were given 6 weeks treatment with captopril in a dose range 75-150 mg/day. Each patient underwent a standard glucose tolerance test and had blood pressure profiles recorded before and after captopril. Supine systolic blood pressure (mmHg) improved from 181 (+/- 16) to 162 (+/- 17) and diastolic blood pressure from 103 (+/- 11) to 89 (+/- 9). A similar improvement was seen in erect systolic (174 +/- 19 to 156 +/- 19) and diastolic (103 +/- 14 to 87 +/- 11) blood pressures. Following treatment there was no significant change in glucose tolerance although the 120 minute plasma glucose value improved from 15.3 +/- 4.2 to 13.9 +/- 3.4 mmol/l (P less than 0.05). The drug was well tolerated and free of adverse effects. Captopril would therefore appear to be an effective and safe anti-hypertensive agent in non-insulin dependent diabetes and did not result in any deterioration of glucose tolerance.

Aged↗
PubMed1985

Regional tidal volume assessed by gated lung imaging.

We have measured regional lung tidal volumes and functional residual capacities by accumulating and framing iso-volumic images while the patient rebreathes 127Xe. As the lung changes shape during ventilation corrections for changes in geometry were obtained by simultaneous collection of 99Tcm counts from the gated perfusion scan. Regions of interest were made to vary throughout the respiratory cycle so that a region had always the same value of 99Tcm counts. From the corrected 127Xe counts regional tidal volumes (TVr) and functional residual capacities (FRCr) were derived. In patients with established chronic bronchitis and emphysema FRCr were greater and the ratio TVr/FRCr decreased compared with patients with relatively normal static and dynamic lung volumes. Preliminary studies suggest that this ratio was a better discriminator between normal and abnormal regional function than estimates of regional xenon washout. Studies with xenon-133 have contributed to our understanding of the physiology of ventilation but have contributed somewhat less to routine clinical practice. This results in part from the unsatisfactory physical properties of xenon-133. Its relatively low gamma ray energy of 80 keV results in significant self-absorption losses and the activity which may be administered is limited by the radiation dose from the associated beta particles so that relatively poor counting statistics are obtained. With inhaled technetium-99m (99Tcm) microspheres imaging conditions are greatly improved but the distribution of these particles may not equate with the distribution of ventilation particularly if wet particles are used. Moreover, simultaneous microsphere perfusion scans with technetium-99m as a label are impossible. Krypton-81m gas has a suitable energy but the short half-life of the rubidium-81m generator (4.7 h) makes supply difficult and the ultrashort half-life of the krypton-81m gas (13 s) leads to problems in calculating the indices of ventilation. Xenon-127 (127Xe) gas has a more favourable dosimetry profile than xenon-133 because it does not have associated beta particles. Further it has an energy (203 keV) suitable for modern gamma cameras and may be used in the presence of injected 99Tcm microspheres to provide simultaneous ventilation/perfusion imaging. Conventional techniques have assumed that a static image of a dynamic process is adequate. As the lungs move during imaging, some account of this respiratory movement should be made.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Evaluating infusion devices: Part I: Facing the issues.

The evaluation of infusion devices for use throughout a hospital can be a complicated and difficult process. An evaluation strategy should be established carefully at the start of the process, with well-defined steps progressing through completion. A complete, accurate evaluation may produce significant resource saving, as well as ultimately enhancing the level of patient care. Part II will address the evaluation of specific infusion pumps.

Humans↗