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Biomedical subjects

D Katz

Publications and source records attributed to D Katz.

252 records · Page 14Linked to original sources
PubMedDate not supplied

Increased levels of surgical adhesions in TGFbeta1 heterozygous mice.

Adhesion formation and fibrosis represent a major complication of surgical intervention. Reducing the morbidity associated with adhesions requires an understanding of the mechanisms underlying their formation. Since increased levels of transforming growth factor-beta1 (TGFbeta1) have been associated with inflammation and adhesion production, we investigated the requirement of TGFbeta1 in peritoneal adhesion formation utilizing mice carrying a targeted disruption of the TGFbeta1 allele. Mice that were either wild-type (+/+), containing two normal alleles of TGFbeta1, or heterozygous (+/-) for the TGFbeta1 null allele received injections of magnesium silicate (talc), and the extent of abdominal adhesions was determined utilizing a standard grading score. Wild-type (+/+) animals had at least twofold more TGFbeta1 protein in peritoneal fluids at 2 h posttrauma compared to heterozygous (+/-) mice (727 vs. 243 pg TGFbeta1/mg protein by enzyme-linked immunosorbent assay (ELISA) in +/+ and +/- mice, respectively), and had significantly less scar and adhesion formation (p < .05) at 7 days posttrauma (1.8 +/- 0.8 vs. 3.4 +/- 1.4, graded from 0 to 5, in +/+ and +/- mice, respectively). These results demonstrate that haploid insufficiency in TGFbeta1 levels can lead to inappropriate matrix and adhesion production during inflammation, and together with previous studies suggest that any perturbation of normal TGFbeta1 levels can modulate the injury response that regulates the extent of adhesion formation.

Animals↗
PubMedDate not supplied

Central venous catheter-induced endocarditis: human correlate of the animal experimental model of endocarditis.

A case of right-sided endocarditis clearly associated with the presence of a right atrial catheter is presented, and the literature on septicemia and endocarditis associated with central venous and pulmonary artery catheterization is reviewed. In the majority of cases of catheter-associated endocarditis reported in the literature, diagnosis has been made at autopsy; echocardiographic diagnosis has been reported only recently. The case presented in this report represents the only case in this literature in which the lesion causing right-sided endocarditis has been identified by two-dimensional echocardiogram and confirmed by tissue diagnosis. The mechanism of direct traumatization of the endocardium by the catheter makes central venous catheter-induced endocarditis bear pathophysiologic similarity to the experimental model of endocarditis in animals.

Adult↗
PubMedDate not supplied

Cyclosporiasis associated with imported raspberries, Florida, 1996.

OBJECTIVES: Until 1995, infection with Cyclospora cayetanenis, a parasite that causes gastroenteritis, was diagnosed in the US primarily in overseas travelers; its modes of transmission were largely unknown. In 1995, 45 cases of cyclosporiasis were diagnosed in Florida residents who had no history of recent foreign travel, but an investigation could not pinpoint a source for the parasite. In 1996, a North American outbreak of cyclosporiasis resulted in more than 1400 cases, 180 of them in Florida. The authors investigated the 1996 Florida outbreak to identify the vehicle of transmission. METHODS: The authors conducted a matched case-control study in which each of 86 laboratory-confirmed sporadic cases was matched with up to four controls. They also investigated nine clusters of cases associated with common meals and attempted to trace implicated foods to their countries of origin. RESULTS: In the case control study, eating raspberries was strongly associated with cyclosporiasis (matched odds ratio = 31.9; 95% confidence interval [CI] 7.4, 138.2). In the cluster investigation, raspberries were the only food common to all nine clusters of cases; a summary analysis showed a strong association between consumption of raspberries and confirmed or probable cyclosporiasis (risk ratio = 17.6; 95% CI 1.9, 188.8). Guatemala was the sole country of origin for raspberries served at six of nine events. CONCLUSIONS: Guatemalan raspberries were the vehicle for the 1996 Florida cyclosporiasis outbreak. Cyclospora is a foodborne pathogen that may play a growing role in the etiology of enteric disease in this country as food markets become increasingly international.

Adult↗
PubMedDate not supplied

Collaborative research and action to control the geographic placement of outdoor advertising of alcohol and tobacco products in Chicago.

Community activists in Chicago believed their neighborhoods were being targeted by alcohol and tobacco outdoor advertisers, despite the Outdoor Advertising Association of America's voluntary code of principles, which claims to restrict the placement of ads for age-restricted products and prevent billboard saturation of urban neighborhoods. A research and action plan resulted from a 10-year collaborative partnership among Loyola University Chicago, the American Lung Association of Metropolitan Chicago (ALAMC), and community activists from a predominately African American church, St. Sabina Parish. In 1997 Loyola University and ALAMC researchers conducted a cross-sectional prevalence survey of alcohol and tobacco outdoor advertising. Computer mapping was used to locate all 4,247 licensed billboards in Chicago that were within 500- and 1,000-foot radiuses of schools, parks, and playlots. A 50% sample of billboards was visually surveyed and coded for advertising content. The percentage of alcohol and tobacco billboards within the 500- and 1,000-foot zones ranged from 0% to 54%. African American and Hispanic neighborhoods were disproportionately targeted for outdoor advertising of alcohol and tobacco. Data were used to convince the Chicago City Council to pass one of the nation's toughest anti-alcohol and tobacco billboard ordinances, based on zoning rather than advertising content. The ordinance was challenged in court by advertisers. Recent Supreme Court rulings made enactment of local billboard ordinances problematic. Nevertheless, the research, which resulted in specific legislative action, demonstrated the importance of linkages among academic, practice, and grassroots community groups in working together to diminish one of the social causes of health disparities.

Adolescent↗
PubMedDate not supplied

Hybrid functional electrical stimulation orthosis system for the upper limb: effects on spasticity in chronic stable hemiplegia.

A new hybrid functional electrical stimulation orthosis system for the upper limb has been designed to allow for ease of use in the home as a daily treatment modality, as well as offer the opportunity for function enhancement. In a pilot study, the system was used by ten patients with chronic stable hemiparesis secondary to cerebral vascular accident and head injuries. The patients were referred by their treating physicians or therapists after meeting the inclusion criteria of good general health, being greater than one year after head injury, or being ten months post-stroke, with no observed neurologic changes in the prior six weeks. Each of these patients had received prolonged physical therapy, either continuous from the initial inpatient rehabilitation treatment or on an intermittent basis over a period of years. The baseline status for factors related to increased muscle tone, i.e., passive range of motion at the wrist and elbow, posture at rest, posture immediately following activity, and spasticity were quantified before the treatment protocol with the functional electrical stimulation orthosis. Active range of motion and tests of functional use of the involved upper limb were also assessed. The patients were instructed in the protocol, trained in the use of the system, and then used the electrical orthosis at home for up to several hours per day. Follow-up assessments were at six months. A statistically significant improvement was noted in all muscle tone/spasticity parameters measured. A separate report will describe the effects on voluntary motion and functional capabilities.

Activities of Daily Living↗
PubMedDate not supplied

Studies on angiotensinogen of plasma and cerebrospinal fluid in normal and hypertensive human subjects.

The presence of a renin-angiotensin system in the central nervous system (CNS) has been demonstrated by several investigators, but little is known regarding the origin of its components. In this study we have compared the immunological and physical-chemical nature of angiotensinogen in plasma and cerebrospinal fluid (CSF) of human subjects and explored whether differences are present in CSF angiotensinogen concentrations of normal and hypertensive subjects. No significant differences in the nature of plasma and CSF angiotensinogen was observed with respect to molecular weight (65-70,000) electrophoretic mobility (RFalb = 0.67 plus or minus 0.003) or angiotensin I (AI) generated (pI = 6.6). Following isoelectric focusing, the plasma angiotensinogen was shown to consist of a single component with an isoionic point of 4.40 plus or minus 0.04. CSF angiotensinogen, on the other hand, resolved into three components (pI = 4.76 plus or minus 0.02; 5.16 plus or minus 0.04; 5.76 plus or minus 0.04). Although no correlations were observed between angiotensinogen levels in the CSF or plasma with blood pressure (BP), a statistically significant difference in angiotensinogen concentration of both plasma and CSF was observed between normotensive and hypertensive subjects. The differences in the chemical and immunological nature of human plasma and CSF angiotensinogens suggest that the angiotensinogen of CSF is not of peripheral origin.

Adult↗
PubMedDate not supplied

Early surgery versus conservative management of dissecting aneurysms of the descending thoracic aorta.

BACKGROUND: Optimal management for patients who present acutely with uncomplicated type III dissections of the descending thoracic aorta remains controversial. Patients with dissecting aneurysms represent a subgroup at high risk of rupture who may benefit from early elective surgery as an alternative to standard medical therapy. METHODS. The authors constructed a Markov decision model to compare the following clinical strategies: 1) early elective surgery immediately after diagnosis (EARLY SURGERY), 2) medical therapy with periodic computed tomography and with elective surgery when aortic diameter is projected to reach 6 cm (CT FOLLOW-UP), and 3) medical therapy with urgent surgery for dissection-related complications (WATCHFUL WAITING). Data sources included Medline (1966-1995) and a case series of patients with type III dissecting aneurysms who received medical therapy with radiographic follow-up. RESULTS: For a typical 60-year-old patient with an acute, uncomplicated 5-cm dissecting aneurysm of the descending thoracic aorta and an operative 30-day mortality rate of 14% for EARLY SURGERY, the model predicts that EARLY SURGERY improves survival compared with CT FOLLOW-UP (9.91 vs 9.44 QALYs). Conservative management may be preferred for patients who have maximum aneurysm diameters < or = 4 cm, are elderly (> or = 75 years), or have higher-than-expected risk of operative mortality. CONCLUSIONS: The choice between early surgery and medical therapy for uncomplicated dissecting aneurysm of the descending thoracic aorta should be tailored to the individual patient's operative risk, risk of dissection-related events, and age. Early surgery may be a reasonable alternative to medical therapy for carefully selected patients at centers with favorable perioperative mortality rates.

Acute Disease↗
PubMedDate not supplied

Potential circuit mechanisms underlying concurrent thalamic and cortical plasticity.

During the last two decades, plastic reorganization of both sensory and motor representations in the adult central nervous system has been demonstrated following a large variety of manipulations, ranging from partial lesions of the sensory receptor surface to modifications in sensory experience (see /14/ for review). Yet, little is known about the neural circuit mechanisms underlying such reorganization process. Despite the difficulty in addressing this issue, recent studies have provided some insights into this fundamental question. Altogether, these studies suggest that the process of plastic reorganization is a system-wide phenomenon, involving both cortical and subcortical representations. Contrary to classical beliefs, recent work also suggests that the final outcome of the reorganization process is not necessarily beneficial, since it can lead to abnormal perceptual experiences /31/, such as the phantom limb sensation, and even pain /31,32/. In this review, we focus on recent insights into the possible circuit mechanisms underlying sensory plasticity and discuss the potential implications of these findings. We then present physiological evidence supporting the view that the process of plasticity observed at the cortical level may reflect simultaneous changes in many subcortical structures.

Animals↗
PubMedDate not supplied

Intraperitoneal infusion of glucose-based dialysate in the rat--an animal model for the study of peritoneal advanced glycation end-products formation and effect on peritoneal transport.

OBJECTIVE: Glucose-based dialysate induces non enzymatic glycation within the peritoneal cavity. To evaluate the relationship between the formation of advanced glycation end-products (AGEs) and peritoneal transfer for small solutes and macromolecules, we developed a model of simulated peritoneal dialysis (PD) in normal rats. METHODS: Male albino rats of the Charles River strain were divided into two sets of 3 groups (15-25 rats in each group). In the experimental (E) group, the rats were intraperitoneally (i.p.) injected daily with a commercially available 4.25% dextrose solution. In the control puncture (CP) group, the peritoneum was punctured daily, but no PD solution infused. In an age-matched control (CC) group, no intervention was given. Two study protocols were used. Protocol A (duration 20 weeks) consisted of a daily i.p. injection of 10 mL PD solution per 100 g body weight. In protocol B, a double volume of PD solution was introduced (20 mL per 100 g body weight). At 9, 16, and 20 weeks in protocol A, and at 9 weeks in protocol B, urea, creatinine, microalbumin [(MAL) measured using specific anti-rat albumin monoclonal antibody], and AGEs (measured by fluorescent assay with excitation at 370 nm and emission at 440 nm) were measured in peritoneal effluent and serum. RESULTS: At no time during the study were AGEs detected in serum from any group in either protocol. In both protocols, no differences were found between the control groups (CP, CC) with respect to all parameters. In protocol A, the dialysate-to-plasma ratio (D/P) of urea was significantly higher in the experimental group as compared with the control groups at 9, 16, and 20 weeks [9 weeks: 0.59 +/- 0.03 (E) vs 0.39 +/- 0.02 (CP) vs 0.46 +/- 0.02 (CC), p < 0.0004 and p < 0.002, respectively; 16 weeks: 0.71 +/- 0.08 (E) vs 0.42 +/- 0.01 (CP) vs 0.46 +/- 0.01 (CC), p < 0.0001 and p < 0.02, respectively; 20 weeks: 0.57 +/- 0.03 (E) vs 0.39 +/- 0.01 (CP) vs 0.41 +/- 0.02 (CC), p < 0.002 and p < 0.004, respectively]. At 16 and 20 weeks, dialysate MAL levels were significantly increased in group E [16 weeks: 354.00 +/- 80.35 microg/mL (E) vs 134.75 +/- 14.36 microg/mL (CP) vs 110.69 +/- 7.83 microg/mL (CC), p < 0.04 and p < 0.03, respectively; 20 weeks: 283.17 +/- 14.71 microg/mL (E) vs 105.14 +/- 12.11 microg/mL (CP) vs 135.50 +/- 19.03 microg/mL (CC), p < 0.00001 and p < 0.0001, respectively]. In protocol B, at completion of the study (week 9), D/P urea, effluent MAL, and AGEs were significantly higher in the experimental group as compared with the control groups [D/P: 0.67 +/- 0.04 (E) vs 0.46 +/- 0.07 (CP) vs 0.41 +/- 0.02 (CC), p < 0.0002 and p < 00001, respectively; MAL: 336.8 +/- 63.30 microg/mL (E) vs 125.71 +/- 16.77 microg/mL (CP) vs 119.00 +/- 39.75 microg/mL (CC), p < 0.008 and p < 0.007, respectively; AGEs: 265.77 +/- 33.49 U/mg creatinine (E) vs 163.10 +/- 21.99 U/mg creatinine (CP) vs 83.17 +/- 22.66 U/mg creatinine (CC), p < 0.02 and p < 0.001, respectively]. Peritoneal effluent AGEs were found to be significantly correlated with D/P urea and dialysate MAL (r = 0.42, p < 0.04, and r = 0.7, p = 0.00001, respectively). CONCLUSIONS: In situ generation of AGEs constitutes the chief origin of peritoneal AGEs. Advanced glycation end-products affect peritoneal permselectivity for both small and large solutes. The rat model of simulated peritoneal dialysis developed in this experiment provides a reliable method for studying peritoneal AGE formation and effect on peritoneal transfer of small solutes and macromolecules.

Animals↗
PubMedDate not supplied

A passive hemagglutination test for detecting bovine serum albumin antibodies.

A microtiter passive hemagglutination test is described for detecting and titrating antibodies in chickens. Chicken erythrocytes are coated with antigen (bovine serum albumin = BSA) in the presence of 0.25% glutaraldehyde. Such sensitized erythrocytes are agglutinated in the presence of antibodies against BSA. The sensitivity and specificity of the test are not affected by salt concentrations in the range of 0.9-9%. This test measures the course of antibody response in chickens immunized with BSA.

Animals↗
PubMedDate not supplied

[Immunology today].

This review covers a large range of dynamic interactions between the genes, molecules and cells of the immune system, which define the conditions of its function and enable a balance to be found between the individual and his environment. The complexity and the flexibility of the system offer alternative or compensatory routes in case of deficiency. This does not become apparent unless the lesion is deep.

Animals↗