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Biomedical subjects

J D Klein

Publications and source records attributed to J D Klein.

At least 19 recordsLinked to original sources
PubMed1992

Factors associated with pediatricians' participation in Medicaid in North Carolina.

OBJECTIVE: To describe the relative importance of factors influencing pediatricians' participation in Medicaid in North Carolina. DESIGN: Questionnaire survey. SETTING AND PARTICIPANTS: Nonacademic primary care pediatricians in direct patient care at least 50% of the time; 332 (85%) of the 389 eligible pediatricians responded. MAIN OUTCOME MEASURES: Proportion of pediatricians who restricted Medicaid patients' access to their practices. The association between restricting access and the following factors was assessed: Medicaid reimbursement, pediatricians' demographic characteristics, knowledge of the Medicaid program, attitudes toward Medicaid patients and the Medicaid program, and beliefs about whether other physicians were available to care for Medicaid patients. RESULTS: Twenty-nine percent of pediatricians restricted Medicaid patients' access to their practices. The proportion of pediatricians restricting access was 62% in cities, 13% in medium-sized towns, and 12% in small towns (P less than .001), but the proportion of pediatricians in cities who restricted access varied from 87% to 22%. Pediatricians who received a higher proportion of their usual fee were less likely to restrict Medicaid patients' access. The relationship between Medicaid payment and restricted access was substantially weakened after controlling for the following factors: (1) the size of the community, (2) pediatricians' attitudes toward Medicaid payment, (3) their perceptions that they were too busy to care for Medicaid patients, and (4) whether there were other resources for the care of Medicaid patients. At comparable levels of payment, rural pediatricians were about six times less likely than urban pediatricians to restrict access. Pediatricians who knew less about Medicaid reimbursement also restricted access more often. Whether or not they restricted access to new Medicaid patients, pediatricians provided acute, preventive, hospital, and emergency care to the Medicaid patients who were already in their practices. CONCLUSIONS: Existing resources for the care of Medicaid patients, pediatricians' economic dependence on Medicaid, and the local norms of practice may be important factors in pediatricians' decision to participate in Medicaid. Increasing reimbursement will have only modest effects on Medicaid participation. Strategies to improve participation should also address pediatricians' knowledge of the Medicaid program and enlist the support of community physicians.

Attitude of Health Personnel↗
PubMed1992

Purification and partial characterization of transglutaminase from Physarum polycephalum.

An intracellular form of calcium ion-dependent transglutaminase (R-glutaminylpeptide:amine gamma-glutaminyltransferase, EC 2.3.2.13) was purified 818-fold to apparent homogeneity from acetone powder preparations of spherules of the acellular slime mold Physarum polycephalum. The enzyme was purified by combined methods of precipitation with 15% (wt/vol) polyethylene glycol, DEAE-cellulose chromatography, and isoelectric focusing in a pH 5 to 7 gradient. The isoelectric point of the enzyme was 6.1. The molecular mass of the denatured enzyme was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 39.6 kDa. A molecular weight of 77,000 was found by gel filtration of the native enzyme on a Superose 12 fast protein liquid chromatography column, indicating that the native functional protein is a dimer. The purified transglutaminase catalyzed the incorporation of [14C]putrescine into protein substrates including casein, N,N'-dimethylcasein, actin purified from P. polycephalum, and actin purified from bovine muscle. Actin was the preferred substrate for the enzyme, both as a purified protein and in crude extracts prepared from P. polycephalum. With N,N'-dimethylcasein as the amine acceptor substrate, [14C]putrescine, [14C]spermidine, and [14C]spermine were all effective amine donor substrates with Km values of 49, 21.4, and 31.7 microM, respectively. All three of these polyamines demonstrated strong substrate inhibition of the enzyme activity between 100 and 200 microM. Upon starvation induced by depletion of a carbon source for growth, the specific activity of this enzyme increased sixfold during the differentiation of P. polycephalum microplasmodia to spherules. This suggests a role for transglutaminase in the construction of spherules, which have the capacity to survive starvation and dessication.

Animals↗
PubMed1992

Regulation of vascular endothelial cell volume by Na-K-2Cl cotransport.

The relationship between cell volume and Na-K-2Cl cotransport was studied in cultured bovine aortic endothelial cells. Hypertonic cell shrinkage increased bumetanide-sensitive, Na- or Cl-dependent K influx without altering bumetanide-insensitive influx. Greater stimulation of cotransport was observed in cells shrunken isosmotically either by preincubation in K-free and Na-free medium or by preincubation in hypotonic medium. Cell swelling, produced by preincubation in isotonic high-K medium, inhibited bumetanide-sensitive K influx. Simultaneous measurements of [3H]bumetanide binding and K influx revealed an increased number of binding sites without an increased influx per binding site in shrunken cells. Bumetanide did not alter the volume or ion content of cells in isotonic or hypertonic medium, indicating that no net influx of ions occurs through cotransport under these conditions. In isosmotically shrunken cells, there was greater stimulation of bumetanide-sensitive influx than of bumetanide-sensitive efflux, resulting in net bumetanide-sensitive influx. Rapid recovery of cell K, Na, and water occurred over 10-20 min and was inhibited by bumetanide or by the removal of external Na or Cl. These data demonstrate that Na-K-2Cl cotransport in aortic endothelial cells is regulated by cell volume, possibly through changes in the number of functional cotransporters, and mediates a brisk regulatory volume increase in isosmotically shrunken cells. Although thermodynamically favored, no net influx occurs through Na-K-2Cl cotransport in cells of normal volume or in hypertonically shrunken cells. This suggests additional regulation of cotransport, perhaps through trans-inhibition by intracellular Cl. Regulation of cell volume by Na-K-2Cl cotransport may be important in maintaining endothelial integrity.

Animals↗
PubMed1992

Childhood typhoid fever diagnosed in an urban U.S. setting.

The majority of cases of childhood typhoid fever diagnosed in the United States occur in persons recently returned from travel abroad. We report two childhood cases of typhoid fever acquired in Mexico and India and diagnosed in an urban United States setting. This report describes these cases and provides insights into the pitfalls in recognizing this condition in a nonendemic setting as well as information concerning differential diagnosis and treatment.

Adolescent↗
PubMed1992

From data to policy ... to politics. The Minnesotans health care plan for universal access to care.

Calls for major reform of the health care delivery system have been sounded at both the state and federal level. However, given the lack of consensus on health care reform at a federal level, more than half of the states are developing initiatives for universal access to care. In 1989, the Minnesota legislature created the Health Care Access Commission to develop a blueprint for universal access in Minnesota. To assist this effort, we studied the extent and nature of uninsurance and underinsurance within the state. In this article we report the findings of that study and discuss how the findings were first used to develop recommendations for universal access legislation. We then describe the fate of the legislation. Finally, we describe the veto and the creation of HealthRight, the recently enacted plan for health care reform bill in Minnesota. This plan simultaneously expands access to care and aims to contain health care costs.

Adult↗
PubMed1992

Candy cigarettes: do they encourage children's smoking?

Candy and bubble gum cigarettes are packaged to resemble cigarette brands, and so they may encourage young children to smoke. Two studies of the role of these products in the development of children's attitudes and behaviors toward smoking were conducted. In the first study, six focus group interviews were conducted with 25 children in three age groups (4 through 5, 6 through 8, and 9 through 11 years old). Children in each group were shown five candy and snack foods and asked about their opinions and experiences with each item. In the second study, 195 seventh-grade students in a southeastern city school system were surveyed about their cigarette smoking and candy cigarette use. In the focus groups, candy cigarettes were recognized by most children. Young children played with the candy cigarettes more than with other candy or snack items and made general references to smoking behaviors. Older children made favorable references to smoking behavior; most knew which stores sold candy cigarettes, and many had chosen to buy and use these items, despite parental disapproval. Candy cigarettes may play a role in the development of children's attitudes toward smoking as an acceptable, favorable, or normative behavior. Elimination of these products should be part of efforts to prevent initiation of smoking by children.

Adolescent↗
PubMed1991

APACHE scores.

Explore the source record for details and available documents.

Intensive Care Units↗
PubMed1991

Adsorption with a soluble E. coli antigen fraction improves the specificity of ELISA tests for Lyme disease.

We reported that preadsorption of patient serum with heat killed E. coli increased the specificity of ELISA for antibodies to Borrelia burgdorferi. That procedure required extra specimen handling and a preincubation. We report the use of a soluble E. coli antigen fraction that is included in serum diluent, eliminating additional steps. Sera from 220 individuals were tested for antibodies to B. burgdorferi. Twenty sera were obtained from patients with Lyme disease and 200 sera were from a population that included healthy controls and patients with different inflammatory conditions (viral infections and various rheumatic disorders). Testing was performed using either a standard serum diluent or one containing soluble E. coli antigen fraction. Results demonstrate that inclusion of soluble E. coli antigen fraction in serum diluent increased assay specificity from 88% for the standard protocol to 98%, with no change in test sensitivity.

Antigens, Viral↗
PubMed1990

Effect of bradykinin on Na-K-2Cl cotransport and bumetanide binding in aortic endothelial cells.

Simultaneous measurements of potassium influx and binding of [3H]bumetanide were performed in endothelial cells cultured from bovine aortas to determine how bradykinin regulates Na-K-2Cl cotransport. [3H]Bumetanide displayed saturable binding and was displaced by low concentrations of unlabeled bumetanide. All three transported ions were required for binding and high concentrations of chloride inhibited binding, consistent with binding of bumetanide to the second chloride site of the transporter. Scatchard analysis of binding under maximal conditions (100 mM sodium, 30 mM potassium, 30 mM chloride) revealed a single class of binding sites with a binding constant of 112 nM and a density of 22 fmol/cm2 or approximately 122,000 sites/cells. Na-K-2Cl cotransport, measured as bumetanide-sensitive potassium influx, was stimulated 118 +/- 30% by bradykinin (p less than 0.01) at physiologic ion concentrations. Stimulation was inhibited by increased potassium or decreased external chloride concentrations and was not seen in conditions required for maximal binding of bumetanide. Simultaneous measurement of the binding of tracer [3H]bumetanide and its inhibition of potassium influx in medium containing 10 mM potassium and 130 mM chloride revealed a turnover number for the cotransporter of 293 +/- 68 s-1 which increased to 687 +/- 105 s-1 with bradykinin (p less than 0.001). There was no change in cell volume and only a 5.6 mM increase in intracellular sodium concentration associated with this stimulation. Bradykinin also increased the affinity of the cotransporter for bumetanide as indicated by a decrease in the Ki for potassium influx from 464 +/- 46 nM to 219 +/- 19 nM (p less than 0.005). Our results show that [3H]bumetanide can be used to quantitate Na-K-2Cl cotransporter sites in aortic endothelial cells and to determine the mechanism by which cotransport is regulated. The stimulation of cotransport in aortic endothelial cells by bradykinin is due to an increase in the activity of existing transporters rather than to an increase in the number of transporters. This, together with the increased affinity for bumetanide, strongly suggests that a change in cotransporter structure is occurring in response to bradykinin.

Animals↗