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Biomedical subjects

E Harvey

Publications and source records attributed to E Harvey.

72 records · Page 4Linked to original sources
PubMed1985

Conservation of oxygen supply using a reservoir nasal cannula in hypoxemic patients at rest and during exercise.

A reservoir nasal cannula which stores oxygen during exhalation and delivers it as a bolus during inhalation has been reported to conserve oxygen delivery in patients with chronic obstructive pulmonary disease (COPD) at rest. We compared the effects upon arterial oxygen saturation (SaO2) of the reservoir cannula and a standard nasal cannula in hypoxemic obstructed and restricted patients at rest and during exercise. The SaO2 was monitored by ear oximeter. While at rest, 13 obstructed and four restricted patients breathed oxygen from the reservoir cannula at 0.5, 1.0, 1.5, and 2.0 L/min and from a standard cannula at 0.5, 1.0, 2.0, 3.0, and 4.0 L/min. Mean SaO2 was significantly higher with the reservoir cannula compared to the standard cannula at 1.0 and 2.0 L/min (p less than 0.0006) and tended to be higher at 0.5 L/min (p less than 0.1). Seven obstructed patients walked on a level treadmill at 0.75 mph while breathing oxygen at 0.5 and 1.5 L/min from the reservoir cannula and at 1.0 and 3.0 L/min from the standard cannula. The SaO2 during exercise with the reservoir cannula was comparable to that with the standard cannula at approximately half of the oxygen flow rate. The ratio of the oxygen flow rate of the standard to the reservoir cannula to produce 90 percent saturation was estimated and found to be 2.5 +/- 0.8 (mean +/- SD) for patients at rest and 2.9 +/- 1.8 during exercise. We conclude that in hypoxemic patients at rest and during exercise, the reservoir cannula uses less than half the oxygen of a standard cannula to produce similar improvement in SaO2 and thus has advantages of a reduced cost of ambulatory therapy with low-flow oxygen and a longer time permitted away from a stationary source of oxygen.

Carbon Dioxide↗
PubMed1983

Rheumatoid arthritis in a Chippewa band. II. Field study with clinical serologic and HLA-D correlations.

We present an in-depth study of rheumatoid arthritis (RA) in a Chippewa band. Of the 227 band members, 168 (74%) were evaluated. The unusually high prevalence of RA was confirmed in 7.1% of those studied or, minimally, 5.3% with a 100% completion rate without additional cases found. Seropositivity in those with clinically definite RA was 92% relative to rheumatoid factor and 75% for ANA. Despite the high prevalence (68%) of HLA-DR4 in this closed population, there was a significant correlation of DR4 with RA (100%). The implications of these observations in this population isolate are discussed.

Adolescent↗
PubMed1981

Mechanisms for albumin-mediated membrane damage.

1. Bee venom phospholipase A2 causes a small increase in the sublytic leakiness of rabbit erythrocytes which is strongly inhibited by lysolecithin and potentiated by albumin. 2. Albumin extracts long-chain fatty acids from the erythrocyte membrane by a process which is faster than diffusion-determined efflux of fatty acid and during the process it greatly increases the sublytic leakiness of the membrane. In contrast, albumin rapidly terminates sublytic responses to lysolecithin. 3. These actions of albumin are abolished only when albumin is preloaded with four molecules of oleic acid per protein molecule. 4. A minor proportion of the response of phospholipase-A2-treated cells to albumin is due to accumulated fatty acid products; the combination of active enzyme and accumulated fatty acids is much more effective than either alone. Membrane partially depleted of phospholipids by enzyme attack is not highly leaky. 5. Albumin may, in part, act by removing lysolecithin, the inhibitory reaction product. A model is proposed in which susceptibility to phospholipase A2 attack is not uniform on the cell surface and is used to explain the inhibitory action of lysolecithin and the high sensitivity of the membrane in the presence of albumin to damage by newly released fatty acids.

Animals↗
PubMed1979

Hepatic clearance mechanism of Tc-99m-HIDA and its effect on quantitation of hepatobiliary function: Concise communication.

Parameters affecting the hepatobiliary clearance of Tc-99m N(2,6-dimethylphenyl carbamoylmethyl) iminodiacetic acid (Tc-HIDA) were evaluated in dogs. Competitive clearance studies, were performed with Tc-HIDA after infusion to plasma saturation levels of an anion, sodium sulfobromophthalein (BSP), and a cation, oxyphenonium. The results demonstrated that Tc-HIDA is transported through hepatocytes by a carrier-mediated organic-anion pathway. The data are consistent with an alteration of the elimination kinetics of Tc-HIDA induced by elevations in the serum bilirubin level, and it is predicted that serum bilirubin at some increased concentration will dominate the distribution and elimination kinetics of Tc-HIDA independently of hepatobiliary status. A quantitative description of liver function in terms of regional distribution and elimination rate constants will require either a pharmacokinetic model that expressly includes the effects of bilirubin, the development of new anionic hepatobiliary agents capable of displacing endogenous bilirubin from transport binding sites, or the development of new hepatobiliary agents that use a different clearance mechanism from that used by bilirubin.

Animals↗
PubMed1979

The biodistribution of Br-77-labeled estrone: visualization of tissues containing increased estrogen receptors.

The biodistribution of a lipid-soluble brominated female sex hormone, Br-77-labeled estrone, has been determined in dogs and rabbits. Following i.v. or intragastric administration, Br-77-labeled estrone localized in the gallbladder bile within 20-25 min. Fifty-six percent of the injected activity was found in the bile at 90 min. Breast tissue was imaged by scintillation camera in three female dogs with postpartum breast enlargement at 24 hr following i.v. injection. Analysis of digitized images revealed 50% more counts per pixel in stimulated female breast tissue than was in surrounding tissue. Increased Br-77 activity in the breast was associated with the presence of increased concentrations of estrogen receptors.

Animals↗
PubMed1977

Technetium-99m-labeled n-(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (tc-99m HIDA): a new radiopharmaceutical for hepatobiliary imaging studies.

An easily formulated, stable kit preparation of technetium-99m HIDA, suitable for use in humans, was developed and tested in mice and dogs. The tracer was cleared rapidly from the blood and excreted predominantly by the liver in both species. In dogs, the hepatobiliary clearance of Tc-99m HIDA was significantly greater than that of C-14 HIDA and Sn-113 HIDA. The LD50 for HIDA in mice, 168 mg/kg, exceeded the average human dose by a factor of 1000 on a per-weight basis. Blood clearance curves for Tc-99m HIDA in 12 normal subjects were biexponential with half-times of 4.6 +/- 1.0 min and 31.5 +/- 7.0 min, and cumulative 90-min urine samples contained 14.2 +/- 1.8% of the injected dose. Images in normal subjects and nonjaundiced patients showed rapid concentration of tracer by the liver and activity was present within the biliary system in 10-20 min. In jaundiced patients, the tracer blood clearance was delayed and urinary excretion increased, but intestinal activity, indicating biliary patency, was imaged in those patients without complete focal obstruction of the common duct. Technetium-99m HIDA is a nontoxic radiopharmaceutical useful for clinical evaluation of hepatobiliary disorders in humans.

Acetanilides↗
PubMed1976

Development of new radiopharmaceuticals based on N-substitution of iminodiacetic acid.

A new approach to radiopharmaceutical design is demonstrated, in which small chelating groups capable of binding gamma-emitting radiometals are attached to biologically active molecules, thus producing radiopharmaceuticals based on bifunctional drug and biochemical analogs. The chelating group iminodiacetic acid has been evaluated for this role by examining two N-substituted iminodiacetic acids: methyliminodiacetic acid (MIDA) and N-(2,6-dimethylphenylcarbamoylmethyl)iminodiacetic acid (HIDA). Radiochemical and biologic studies showed that both agents were obtained in high radiochemical purity, were stable in vitro and in vivo, and possessed biologic distributions governed almost exclusively by the N-substituted group. These characteristics of 99mTc-labeled N-substituted iminodiacetic acids, prepared using an "instant kit" method, provide the basis for a valuable new class of radiopharmaceuticals based on bifunctional drug and biochemical analogs.

Animals↗
PubMedDate not supplied

Efficacy of gastrostomy feeding in infants and older children receiving chronic peritoneal dialysis.

OBJECTIVE: To assess the efficacy of supplemental gastrostomy tube (g-tube) feeding in infants and children receiving chronic peritoneal dialysis (CPD). DESIGN: Retrospective observational study. SETTING: Pediatric nephrology division of tertiary care center. PATIENTS: Fifteen patients undergoing g-tube insertion while receiving CPD were included in the study, and were subdivided, on the basis of age, into the following groups: infants (< or = 2.5 years, n = 8); older children (> 2.5 years, n = 7). MAIN OUTCOME MEASURES: Assessment of the effect of CPD and g-tube feeding on statural growth assessed by height standard deviation score (SDS) and percentage weight-for-height, and measured anthropometric variables including triceps skinfold thickness (TSF), midarm muscle circumference (MAMC), and midarm mean circumference (MAC). Assessment of the effects of CPD and g-tube feeding on measured biochemical variables including total protein, albumin, cholesterol, triglycerides, and high density lipoprotein. RESULTS: No significant change in height SDS was observed; however, the reported continuing decline in height SDS in infants was arrested. Percentage weight-for-height increased significantly in infants at 6 months (p = 0.008) and 12 months (p = 0.006) following initiation of g-tube feeding. An increase was also observed in the older child group, being significant at 12 months (p = 0.031) following g-tube insertion. Increases in all anthropometric variables occurred in the infant group during CPD and post g-tube insertion, significant only for MAMC at 12 months (p = 0.037) post g-tube insertion. In older children little change occurred during CPD, with all variables increasing post g-tube insertion, significant only for MAMC at 6 months (p = 0.02) and 12 months (p = 0.02). An increase in total protein and albumin was noted; however, no significant changes in any biochemical parameters were observed. CONCLUSIONS: Supplemental g-tube feeding facilitates weight gain in infants and older children receiving CPD and arrests the decline in height SDS traditionally observed in infants with end-stage renal disease. No significant alteration was observed in measured biochemical variables, although an increase in total protein and albumin was noted.

Anthropometry↗