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Biomedical subjects

J D Klein

Publications and source records attributed to J D Klein.

At least 73 records · Page 4Linked to original sources
PubMed1997

When will managed care come to anesthesia?

Managed care has begun to reshape many areas of health care practice, but anesthesia is not yet among them. The economics of anesthesia care are characterized by widespread inefficiency in the allocation of labor, and a unique market structure that poses special challenges to managed care influence. The potential for savings is great, perhaps as much as a one percent decrease in commercial health costs. But these savings can only be realized if managed care organizations are able to restructure the incentives facing anesthesia professionals to promote innovation, cooperation, and shared benefits of efficiency improvements.

American Hospital Association↗
PubMed1996

Geographic variation in the management and outcome of patients with AIDS-related Pneumocystis carinii pneumonia.

Pneumocystis carinii pneumonia (PCP) is one of the most common reasons for the hospitalization of AIDS patients; however, geographic differences in PCP management have not been evaluated previously. Therefore, we abstracted data on socioeconomic characteristics, prior HIV care, severity of illness, timeliness and intensity of in-hospital care, duration of hospitalization, and survival from 1547 randomly selected medical records of patients hospitalized with AIDS-related PCP between 1987 and 1990 at 82 hospitals in Chicago, Los Angeles, Miami, New York City, and Raleigh-Durham, North Carolina. Multivariate regression models were used to assess factors associated with longer hospital stays and increased inpatient mortality. Our results showed that in-hospital mortality ranged from 15% to 27%, bronchoscopy rates from 53% to 70%, and mean length of stay from 14 days to 23 days. Geographic variations in mortality were accounted for by differences in severity of illness at admission, insurance status, and in-hospital patient management. However, significant regional variations in hospital length of stay persisted, even after adjusting for patient demographics, severity of illness, and use of diagnostic and therapeutic care resources.

AIDS-Related Opportunistic Infections↗
PubMed1996

Perioperative nutrition and postoperative complications in patients undergoing spinal surgery.

STUDY DESIGN: The authors undertook a three-part study to better understand the impact of perioperative nutritional status on postoperative complications in patients undergoing spinal surgery. In preliminary Parts I and II, the authors targeted two groups of patients who are particularly nutritionally challenged. In Part III, they studied a large group of consecutive patients undergoing routine lumbar spinal fusion. OBJECTIVES: To determine whether preoperative nutritional status was a significant predictor of postoperative complications in patients undergoing elective lumbar spinal fusion. SUMMARY OF BACKGROUND DATA: In Part I, 27 patients treated surgically for vertebral osteomyelitis were divided into two groups based on their preoperative nutritional status. Twenty-four of the 26 postoperative complications were in the malnourished group (P < 0.001). In Part II, 15 (75%) of 20 patients treated surgically for spinal cord injury were found to become malnourished in the postoperative period. Seventeen complications were noted, all in the malnourished group (P = 0.001). METHODS: One hundred fourteen consecutive patients undergoing selective lumbar decompression and fusion were identified and their records reviewed. In addition to preoperative nutritional status, data gathered included age, sex, height, weight, past medical history, steroid use, alcohol use, tobacco use, type of bone graft (allograft vs. autograft), history of previous lumbar surgery, number of levels fused, and use of spinal instrumentation. RESULTS: Eleven of 13 postoperative infectious complications (10 deep wound infections) were noted in the malnourished group (P < 0.001). By stepwise logistic regression analysis, preoperative nutritional status was an extremely significant independent predictor of postoperative complications in patients undergoing elective lumbar spinal fusion (P = 0.0018). CONCLUSIONS: The prevalence data in our study population suggest that a large number (25%) of patients undergoing elective lumbar spine surgery are nourished inadequately at surgery. This number is higher (42%) in older patients. The authors recommend that close attention be paid to the perioperative nutritional status of patients undergoing lumbar spinal surgery. Patients with suboptimal nutritional parameters should be supplemented and replenished before elective surgery.

Adult↗
PubMed1996

Changes in aquaporin-2 protein contribute to the urine concentrating defect in rats fed a low-protein diet.

Low-protein diets cause a urinary concentrating defect in rats and humans. Previously, we showed that feeding rats a low (8%) protein diet induces a change in urea transport in initial inner medullary collecting ducts (IMCDs) which could contribute to the concentrating defect. Now, we test whether decreased osmotic water permeability (Pf) contributes to the concentrating defect by measuring Pf in perfused initial and terminal IMCDs from rats fed 18 or 8% protein for 2 wk. In terminal IMCDs, arginine vasopressin (AVP)-stimulated osmotic water permeability was significantly reduced in rats fed 8% protein compared to rats fed 18% protein. In initial IMCDs, AVP-stimulated osmotic water permeability was unaffected by dietary protein. Thus, AVP-stimulated osmotic water permeability is significantly reduced in terminal IMCDs but not in initial IMCDs. Next, we determined if the amount of immunoreactive aquaporin-2 (AQP2, the AVP-regulated water channel) or AQP3 protein was altered. Protein was isolated from base or tip regions of rat inner medulla and Western analysis performed using polyclonal antibodies to rat AQP2 or AQP3 (courtesy of Dr. M.A. Knepper, National Institutes of Health, Bethesda, MD). In rats fed 8% protein (compared to rats fed 18% protein): (a) AQP2 decreases significantly in both membrane and vesicle fractions from the tip; (b) AQP2 is unchanged in the base; and (c) AQP3 is unchanged. Together, the results suggest that the decrease in AVP-stimulated osmotic water permeability results, at least in part, in the decrease in AQP2 protein. We conclude that water reabsorption, like urea reabsorption, responds to dietary protein restriction in a manner that would limit urine concentrating capacity.

Animals↗
PubMed1996

The role of community health centers in providing preventive care to adolescents.

OBJECTIVES: To (1) compare preventive health visits by poor and nonpoor adolescents, (2) describe adolescent users of community health centers (CHCs), (3) investigate adolescent preventive visits to CHCs, and (4) determine factors independently associated with timely preventive visits. DESIGN: Analysis of the nationally representative sample of 6635 adolescents aged 11 to 17 years in the Child Health Supplement to the 1988 National Health Interview Survey. RESULTS: Overall, 4% of US adolescents used CHCs for routine health care, and the percentage was higher for poor compared with nonpoor adolescents (11% vs 3%, P < .01). Although CHC users were more likely to be poor (41% vs 10%, P < .001), uninsured (23% vs 10%, P < .001), and to have behavior (16% vs 9%, P = .02) and school problems (56% vs 43%, P < .001), they were as likely to have had timely preventive visits (83% vs 81%, P = .61) as adolescents who used private practices. Using logistic regression, timely adolescent preventive visits were independently associated with having a source for routine care (odds ratio, 4.1; 95% confidence interval, 3.3-5.2), a chronic health condition (odds ratio, 1.2; 95% confidence interval, 1.0-1.5), and the use of seat belts all or most of the time (odds ratio, 1.4; 95% confidence interval, 1.2-1.6), but no independent association was observed between poverty status and timely preventive visits. CONCLUSIONS: Community health centers are an important source of preventive care for impoverished adolescents. Although those who use CHCs have greater psychosocial problems, they seek preventive care as regularly as those using private practices. Thus, periodic comprehensive visits may be an effective strategy for CHCs to provide preventive services to adolescents.

Adolescent↗
PubMed1996

Tuboovarian abscess and peritonitis caused by Streptococcus pneumoniae serotype 1 in young girls.

Streptococcus pneumoniae is a frequent bacterial cause of pneumonia, bacteremia, meningitis, and otitis media in infants and children. Primary pneumococcal peritonitis, however, is rare in children and is usually associated with an underlying medical condition (such as nephrotic syndrome) or with upper genital tract disease in females, Pneumococcal upper genital tract infections in the premenarchal child are extremely unusual. Epidemiologic reviews of pneumococcal serotypes causing infection in children have indicated that serotype 1 is an uncommon pathogen of pelvic disease in children. We describe three children who presented with abdominal pain and a toxic appearance; appendicitis was initially suspected in all three children, but peritonitis due to S pneumoniae serotype 1 was subsequently diagnosed in all three. Each child had a tuboovarian abscess that was demonstrated radiographically. Two children had complicated courses, but all ultimately recovered. The epidemiology and possible tropism of serotype 1 isolates for the female upper genital tract are discussed.

Abdominal Abscess↗
PubMed1996

Environmental and life-style risk factors for Lyme disease in children.

Risk factors for Lyme disease and/or infection with Borrelia burgdorferi in children are not defined. A case-control study was performed using Lyme disease patients from our Lyme Clinic population. Age- and sex-matched controls from the same neighborhood were identified by the Lyme patients' families. A site visit was made to each case/control neighborhood. Twenty-four environmental variables, especially the ecologic characteristics of the home environment were examined. Forty-five items were surveyed by parent questionnaire, including certain "high-risk" activities and behaviors, whether ticks or certain animals were present on the property, and whether antitick measures were used. Control subjects had serologic assays for antibodies to B. burgdorferi. Forty-four Lyme disease patients and 44 well-matched control subjects participated; 2 controls were seropositive. Significant associations with Lyme disease were found for deer ticks in the home environment, ground cover containing moist humus, and leaf litter in the yard. Among the 45 items related to life-style, there was no correlation with Lyme disease for the use of any antitick measures or for any childhood activities; in fact, an inverse correlation was observed for camping and fishing. We conclude that conditions in the immediate home environment, including certain ecologic factors that favor the presence of Ixodes ticks, are associated with an increased risk for Lyme disease in children.

Adolescent↗
PubMed1996

Release of the flexor hallucis longus tendon in ballet dancers.

Thirteen female ballet dancers had an operative release of the flexor hallucis longus tendon because of isolated stenosing tenosynovitis, and the results were reviewed after a mean duration of follow-up of six years and six months (range, two to ten years). All of the patients danced at the advanced or professional level, and all had failed to respond to non-operative management. The mean age of the patients at the time of the operation was twenty years (range, thirteen to twenty-six years). Symptoms, which included pain and tenderness over the medial aspect of the subtalar joint, had been present for a mean of six months (range, two to twelve months) preoperatively and were exacerbated by jumping and by attempts to perform en pointe work. Crepitus was present in six patients, and triggering was present in three. No patient had evidence of a symptomatic os trigonum. Postoperatively, all patients participated in a formal physical-therapy program for a mean of nine weeks (range, four to thirteen weeks). All patients returned to dancing, within a mean of five months (range, two to nine months), and eleven reached a level of full participation in dancing without restriction. At the time of the most recent follow-up, all patients noted improvement compared with the pre-operative condition. Eight patients were professional ballet dancers, four were students at advanced ballet schools, and one had stopped performing ballet for reasons unrelated to the tenosynovitis of the flexor hallucis longus. In addition, two of the students had decided not to pursue careers in dancing because of persistent, but greatly diminished, symptoms. No complications were noted in this series. We concluded that an operative release of the flexor hallucis longus is effective for the treatment of isolated stenosing tenosynovitis in female ballet dancers who place high demands on the foot and ankle and for whom non-operative treatment has failed.

Adolescent↗
PubMed1996

Nutritional status in the patient with spinal infection.

Patients that undergo spinal reconstructive surgery are nutritionally at risk. The elderly, the chronically ill, and the developmentally disabled are often malnourished preoperatively. Those patients undergoing combined or staged anterior and posterior procedures often become malnourished in the postoperative period. Poor nutritional status is unequivocally associated with increased postoperative complications, including infectious complications. Close attention should be paid to the perioperative nutritional status of these patients and strong consideration given to preoperative and postoperative nutritional supplementation when indicated.

Aged↗
PubMed1995

Clinical preventive services efficacy and adolescents' risky behaviors.

OBJECTIVE/BACKGROUND: To analyze the value of studying or implementing office-based clinical preventive services for adolescents. Most adolescent mortality and morbidity is attributable to risky behaviors, yet clinical preventive services to reduce risky behaviors are often challenged because their efficacy has not been demonstrated. DESIGN: A cost-effectiveness model of adolescents' risky behaviors that compares standard practice with a program of screening visits for all adolescents and counseling visits for youth identified as high risk. We considered two risky behaviors, alcohol abuse and unsafe sexual activity, and five outcomes. MAIN OUTCOME MEASURES: Baseline cost-effectiveness of the program, minimum efficacy at which the program would be cost-effective, and sample sizes required for a trial of the program. RESULTS: Assuming that the program is 5% effective at preventing risky behaviors, it would cost $3035 to prevent any one adverse outcome and $471,000 to prevent a death from an automobile crash or from human immunodeficiency virus infection. Assuming society were willing to pay $600,000 to prevent a death (a generally accepted figure), the program would be cost-effective only if it were 5.6% effective at changing behavior. At this efficacy, the program would have a cost per year of life saved comparable to or better than many other accepted medical interventions. However, to demonstrate changes in outcomes at this efficacy would require a clinical trial with between 4000 and 95 million adolescents in each treatment group, depending on the outcome measured. CONCLUSIONS: Studying the ability of clinical preventive services to prevent outcomes of adolescents' risky behaviors would be impractical. The decision to implement these programs should be made based on current knowledge and beliefs; their efficacy can probably be studied only as part of widespread implementation.

Adolescent↗
PubMed1995

School-based health clinics in the mid-1990s.

School-based health clinics have grown in number from one or two in the early 1970s to more than 600 in the 1990s. The main focus of school-based clinics is to provide primary health care and psychosocial counseling to children and adolescents in schools. This article reviews the distribution and availability of school-based clinics in 1994, discussing various models and definitions for school-based health services, the health and educational impact of school-based clinics on adolescents, and the policy issues of concern to school-based health clinics in the current era of health care and health financing reform.

Adolescent↗
PubMed1995

Shrinkage-induced activation of Na+/H+ exchange in primary rat astrocytes: role of myosin light-chain kinase.

Primary rat astrocytes exposed to hyperosmotic solutions undergo Na(+)-dependent amiloride-sensitive alkalinization of 0.36 U [measured with the pH-sensitive fluorescent dye 2',7'-bis(carboxyethyl)-5(6)-carboxy-fluorescein], suggesting that shrinkage-induced alkalinization is due to activation of Na+/H+ exchange (NHE). Alkalinization is maintained for at least 20 min, and is readily reversible and ATP dependent. Hyperosmotic solutions produced no increase of intracellular Ca2+ or adenosine 3',5'-cyclic monophosphate (cAMP). Loading cells with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, a Ca2+ chelator, or depleting cells of protein kinase C (PKC) had no effect on activation of NHE. Thus shrinkage-induced activation of NHE does not involve cAMP, Ca2+, or PKC. However, ML-7, an inhibitor of myosin light-chain kinase (MLCK), inhibited shrinkage-induced activation with a half-maximal inhibition of 56 microM. This activation was also inhibited by 500 microM N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, 100 microM chlorpromazine, and 50 microM trifluoperazine, all calmodulin inhibitors. Shrinkage increased the phosphorylation of an 18-kDa protein that colocalizes with myosin light chain. Our data suggest that shrinkage-induced activation of NHE in astrocytes occurs via a novel pathway involving activation of calmodulin-dependent MLCK and phosphorylation of myosin light chain.

Adenosine Triphosphate↗
PubMed1995

Volume-sensitive myosin phosphorylation in vascular endothelial cells: correlation with Na-K-2Cl cotransport.

To identify protein kinases that are regulated by cell volume, we examined protein phosphorylation in hypertonically shrunken aortic endothelial cells. Shrinkage reversibly increased, and swelling decreased, phosphorylation of a 19-kDa cytoskeletal protein identified as myosin light chain (MLC) by immune precipitation and immunoblotting. Shrinkage also increased MLC phosphorylation in human umbilical vein endothelial cells, rat aortic smooth muscle cells, and human dermal fibroblasts. Phosphorylation was blocked by ML-7, an inhibitor of MLC kinase (MLCK). Neither inhibition of protein kinase C nor inhibition of myosin phosphatase (with calyculin) altered MLC phosphorylation. Peptide mapping of MLC indicated phosphorylation by MLCK. Na-K-2Cl cotransport activation paralleled MLC phosphorylation in hypertonic medium. Na-K-2Cl was stimulated by low concentrations of ML-7 with no further stimulation by hypertonic shrinkage and was inhibited by higher concentrations, paralleling inhibition of MLC phosphorylation. Shrinkage-induced phosphorylation of the cotransporter was not blocked by ML-7. We conclude that cell volume regulates MLC phosphorylation by MLCK. MLCK influences Na-K-2Cl cotransport but independently of cotransporter phosphorylation. These data suggest an important link between cell volume, volume-regulatory transporters, and the contractile state of the cytoskeleton.

Animals↗