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H H Davis

Publications and source records attributed to H H Davis.

8 recordsLinked to original sources
PubMed1992

Hemolytic-uremic syndrome associated with ingestion of quinine.

Hemolytic-uremic syndrome following quinine ingestion is a newly described phenomenon, with just two previous descriptions of 4 cases in the literature. We describe a 5th case. The reaction may be mediated by the presence of antibodies reactive against platelets in the presence of quinine. Treatment has included use of plasma exchange, prednisone, aspirin, and dipyridamole. The patients have all regained some degree of renal function. However, it is unclear whether pharmacological treatment or spontaneous resolution is responsible for the improvement. Quinine-associated hemolytic-uremic syndrome probably occurs more often than is recognized. It is important to recognize this reaction when it occurs and to avoid further quinine exposure, since the reaction seems to be recurrent.

Biopsy↗
PubMed1979

Indium-III: a new radionuclide label for studying human platelet kinetics.

Indium-III. when complexed with 8-hydroxyquinoline (oxine), has been employed as a radioactive platelet label for thrombus imaging in animals and man. The short half-life (2.8 d) and high yield of gamma photons of 111In make it ideal for in vitro counting and external imaging. To evaluate its suitability for studies of platelet turnover in man, platelet kinetic studies were carried out on 10 healthy volunteers using 111In-and 51Cr-platelets concurrently. For 111In labelling, platelets were harvested by differential centrifugation from 43 ml of whole blood drawn into acid-citrate dextrose (ACD) solution. The platelets were washed and suspended in a mixture of ACD and isotonic saline and then incubated with 111In-oxine, rewashed, and suspended in plasma for reinfusion. 51Cr labelling was performed using standard methods. Mean labelling efficiency was 73% with 111In and 6.5% with 51Cr. In vitro studies demonstrated minimal release, elution, and reutilization of the 111In label. There was no significant difference in the aggregation response of 111In- and 51Cr-platelets to ADP and collagen. The in vivo recovery of 111In-platelets was approximately 50% greater than that of 51Cr-platelets whereas the platelet life spans were similar. These results indicate that 111In labelled platelets may be useful for thromobokinetic studies in man. The new method offers the advantages of reduced blood requirements, higher labelling efficiency, and the ability to perform external imaging of platelet distribution in vivo.

Adult↗
PubMed1978

Scintigraphic detection of atherosclerotic lesions and venous thrombi in man by indium-111-labelled autologous platelets.

Accumulation of autologous platelets labelled with indium-111 at sites of atherosclerosis or venous thrombosis was demonstrated by scintigraphy in three patients. The lesions detected were bilateral ulcerated carotid-artery plaques, iliofemoral venous thrombosis, and renal-vein thrombosis. This technique shows promose as a non-invasive means of diagnosing focal atherosclerotic and thrombotic lesions.

Arteriosclerosis↗
PubMed1978

Alveolar-capillary oxygen disequilibrium in hepatic cirrhosis.

Hypoxemia is a frequent occurrence in patients with severe hepatic disease. Multiple mechanisms have been implicated in the production of such hypoxemia. The case of a 35-year-old man with cyanosis, clubbing, and cirrhosis is presented. Physiologic data from this patient revealed normal pulmonary function, except for a low diffusing capacity and a 28 percent shunt while the patient was breathing 100 percent oxygen. A perfusion scan with radioactive 99mtechnetium-labelled macroaggregated albumin revealed 67 percent of the labelled macroaggregated albumin in the systemic circulation. Post-mortem examination demonstrated normal pulmonary parenchyma, markedly dilated intraparenchymal capillaries and arterioles, subpleural angiomata, and cirrhosis. No anatomic arteriovenous connections were demonstrated before or after death. We conclude that the arterial hypoxemia of some patients with hepatic cirrhosis results from dilated gas-exchanging blood vessels. These widened vessels prevent end pulmonary capillary oxygen tension from reaching equilibrium with alveolar gas, perhaps because of the widened distance for diffusion.

Adult↗
PubMed1977

Scintigraphic diagnosis of experimental pulmonary embolism with In-111-labeled platelets.

Stasis thrombi, radiolabeled with Tc-99m sulfur colloid, were produced in six dogs by the injection of human thrombin into isolated jugular vein segments. After release of the thrombi, scintigraphic images demonstrated 16 pulmonary emboli containing Tc-99m. Autologous platelets labeled by the In-111 oxine method were injected. Sequential images demonstrated platelet accumulation in 14 of the 16 emboli within 1 hr. The emboli were recovered at autopsy and their activity assayed. The mean uptake of In-111-labeled platelets was 1.1% dose/g of embolus, and the mean embolus-to-blood ratio was 16. Our results demonstrate that fresh pulmonary emboli in dogs can be detected by imaging with In-111-labeled platelets, and suggest that radiolabeled platelets may provide a simple, noninvasive method for the direct visualization of pulmonary emboli in patients.

Animals↗