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H R Kimball

Publications and source records attributed to H R Kimball.

At least 37 records · Page 2Linked to original sources
PubMed1993

A core component of the certification examination in internal medicine.

OBJECTIVE: To develop and test the psychometric characteristics of an examination of core content in internal medicine. DESIGN: A cross-sectional pilot test comparing the core examination with the 1988 certifying examination and two pretest examinations. SETTING: The 1988 certifying examination of the American Board of Internal Medicine. PARTICIPANTS: A random sample of 2,975 candidates from 8,968 candidates who took the 1988 certifying examination were given the core examination; similarly drawn samples were each given one of two pretests of traditional questions. INTERVENTIONS: A framework for developing an examination of core internal medicine questions was designed and used to develop a 92-question core test with an absolute pass/fail standard. RESULTS: Candidates answered 74% of core internal medicine questions, compared with 64%, 52%, and 53% of traditional questions on the 1988 certifying examination and the two pretests. The discriminating ability of the core internal medicine examination was lower than that of the certifying examination (r-values were 0.28 and 0.34, respectively). The pass rate was 83% for the core internal medicine examination and 57% for the certifying examination; 27% passed the core examination and failed the certifying examination; 1% passed the certifying examination and failed the core examination. CONCLUSION: Core internal medicine questions were easier than but almost as discriminating as traditional questions of the certifying examination. A small percentage of candidates passed the certifying examination but failed the core examination.

Certification↗
PubMed1975

Lysosomal enzymes in normal and Chediak-Higashi blood leukocytes.

A method of blood granylocyte concentration and isolation of granules from both normal and neutropenic Chediak-Higashi syndrome (CHS) patients is described. the intracellular distribution of activity for several hydrolases in CHS granulocytes differs from normal; significantly more activity is present in the cytoplasmic fraction and correspondingly less is granule-associated. Isolated CHS granules are not more sensitive to the labilizing agents vitamin A, progesterone, or etiocholanolone. Specific activities of myeloperoxidase and ss-glucuronidase in CHS granulocytes are lower than normal while alkaline phosphatase is elevated. Other lysosomal enzyme activities are normal. Lysosomal enzyme distribution and content are similar in CHS and normal mononuclear cells. The possible significance of these findings is discussed.

Acid Phosphatase↗
PubMed1974

Separation and characterization of human neutrophil granules.

Human blood neutrophilic leukocytes were separated and purified by modifications of the Hypaque/Ficoll and dextran separation methods, resulting in a suspension which was greater than 96% neutrophils. Neutrophils were prepared in 0.34 M sucrose containing heparin and were clarified of nongranular debris by sequential passage through polycarbonate filters of pore size 5 mu and 2 mu. Isopycnic sucrose gradients of such filtrates revealed three major bands. The gradient separated fractions were studied by electron microscopy including peroxidase cytochemistry and by enzyme assay for myeloperoxidase (MPO), beta-glucuronidase, muramidase alkaline phosphatase and acid phosphatase utilizing both p-nitrophenylphosphate (pnp) and beta-glycerophosphate as substrates. Peroxidase-positive granules were observed at both density 1.22 (band A) and density 1.20 (band B). Three peroxidase-negative granules were identified: the round or oval peroxidase-negative granule of density 1.22 (band A) and two smaller granules, distinguishable by size and shape at density 1.18 (band C). Band C granules contain crystalloid inclusions. Peaks of muramidase activity coincided with bands A and C, suggesting the presence of muramidase in the peroxidase-negative granules of density 1.22 and in one or both of the peroxidase-negative granules at density 1.18. beta-Glucuronidase was distributed like MPO, with a major peak in band B and a minor peak in band A. Acid beta-glycerophosphatase was largely in band A. Acid pnp phosphatase was nonspecifically associated with soluble nongranular protein which always remained at the origin of sucrose gradients. Alkaline phosphatase was not granule associated and sedimented alone to density 1.145, which is highly suggestive of a cytoplasmic membrane localization for this enzyme.

Acid Phosphatase↗
PubMed1972

Studies of neutrophil production and turnover in grey collie dogs with cyclic neutropenia.

12 grey collie dogs had cyclic neutropenia with the neutropenia recurring at 11.8+/-0.1-day intervals. The recovery from neutropenia was accompanied by a single wave of myeloid proliferation, an increase in marrow myeloid-labeling indices, and an increase in serum muramidase levels. After recovery from neutropenia during the period when blood neutrophils (PMN) were normal or increased, marrow myeloid precursors became scarce. The decline in marrow precursors and marrow PMN reserves heralded the recurrence of neutropenia. Neither diisopropyl fluorophosphate (DF(32)P) leukokinetic studies nor the rate of development of neutropenia suggested shortened PMN survival as a mechanism for the neutropenia. These studies indicate that the cyclic neutropenia is due to a regularly recurring failure in PMN production.

Agranulocytosis↗
PubMed1971

Defective granulocyte chemotaxis in the Chediak-Higashi syndrome.

In vivo and in vitro studies of granulocyte chemotaxis were performed in three patients with the Chediak-Higashi syndrome. Rebuck skin windows showed a decreased accumulation of leukocytes at an inflammatory site. Studies in Boyden chambers documented a cellular defect in granulocyte chemotaxis. The chemotactic response of Chediak-Higashi cells by this technique averaged approximately 40% of normal and was consistently reduced using several different chemotactic stimuli. This deficit was magnified by shortening the chamber incubation time or by decreasing the pore size of the micropore filter and was independent of granulocytopenia. No abnormalities of passive motility, adhesiveness, viability, or pH optimum for migration were found in these cells. Chediak-Higashi serum contained no inhibitors of chemotaxis and was capable of generating normal amounts of chemotactic factors with the exception of one patient with the accelerated phase of the disease. Heterozygotes for the Chediak-Higashi trait had normal chemotactic function. This cellular defect in chemotaxis may contribute to the marked susceptibility to pyogenic infections which is so characteristic of patients with the Chediak-Higashi syndrome.

Adolescent↗