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Biomedical subjects

K Brown

Publications and source records attributed to K Brown.

At least 307 records · Page 17Linked to original sources
PubMed1993

Influence of dietary calcium on chlordecone-induced biochemical changes in serum of rat.

Male, Sprague-Dawley rats were treated with different (1, 10, 50, and 100 ppm) concentrations of chlordecone (Cd) in calcium-sufficient (Ca-S) or calcium-deficient (Ca-D) diet for 15 days. No significant changes in serum total proteins were observed. However, serum nonprotein nitrogen compounds (urea, uric acid, and creatinine) and glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, creatine kinase, and alkaline phosphatase were significantly increased at 50 and 100 ppm of Cd. Chlordecone induced more increase in these serum components of rats fed with Ca-D as compared to Ca-S diet. Increased serum nonprotein nitrogen compounds and enzymes indicate Cd-altered glomerular and hepatic functions.

Animals↗
PubMed1993

Genetic and physical mapping of the Treacher Collins syndrome locus with respect to loci in the chromosome 5q3 region.

Treacher Collins syndrome is an autosomal dominant, craniofacial developmental disorder, and its locus (TCOF1) has been mapped to chromosome 5q3. To refine the location of the gene within this region, linkage analysis was performed among the TCOF1 locus and 12 loci (IL9, FGFA, GRL, D5S207, D5S210, D5S376, CSF1R, SPARC, D5S119, D5S209, D5S527, FGFR4) in 13 Treacher Collins syndrome families. The highest maximum lod score was obtained between loci TCOF1 and D5S210 (Z = 10.52; theta = 0.02 +/- 0.07). The best order, IL9-GRL-D5S207/D5S210-CSF1R-SPARC-++ +D5S119, and genetic distances among these loci were determined in the 40 CEPH families by multipoint linkage analysis. YAC clones were used to establish the order of loci, centromere-5'GRL3'-D5S207-D5S210-D5S376-CSF1R -SPARC-D5S119-telomere. By combining known physical mapping data with ours, the order of chromosome 5q3 markers is centromere-IL9-FGFA-5'GRL3'-D5S207-D5S210- D5S376-CSF1R-SPARC-D5S119-D5S209- FGFR4-telomere. Based on this order, haplotype analysis suggests that the TCOF1 locus resides distal of CSF1R and proximal to SPARC within a region less than 1 Mb in size.

Base Sequence↗
PubMed1993

The effects of dietary calcium and chlordecone on cholinesterase, triglycerides, low density lipoproteins, and cholesterol in serum of rat.

Male, Sprague-Dawley rats were treated with 0, 1, 10, 50, 100 ppm chlordecone (Cd) mixed in calcium-sufficient (Ca-S) or calcium-deficient (Ca-D) diet for 15 days. A significant decrease in body weight gain was observed in 100 ppm of Cd-treated rats. Cholinesterase (ChE) activity was significantly decreased in serum of Ca-D rats. Chlordecone did not alter serum ChE activity in both Ca-S and Ca-D rats. However, Cd decreases serum triglycerides, low density lipoproteins (LDL) and cholesterol in both Ca-S and Ca-D rats. Rats fed with Ca-S or Ca-D diet exhibited differential sensitivity to Cd-toxicity. Decreased levels of serum triglycerides, LDL and cholesterol suggest that Cd might interfere in lipid metabolism.

Animals↗
PubMed1993

Distinguishing instrumental and hostile aggression: does it make a difference?

An analogue task of instrumental and hostile aggression during a competitive game, modified to minimize overlap between aggressive responses, was evaluated in 8- to 14-year-old clinically referred boys (n = 33). Postgame interviews indicated that the hostile response, an aversive noise, was perceived by over 80% of subjects as hostile and not instrumental. In contrast, the instrumental response, blocking the opponent's game, was perceived about equally as having instrumental and hostile functions. The hostile aggressive response was uniquely correlated with continuous performance task impulsive commission errors (r = .51), which supported the theoretical relation of hostile aggression to poor impulse control. These results suggest that instrumental and hostile aggression can be distinguished and when precisely defined are distinct in theoretically important ways.

Adolescent↗
PubMed1993

Effects of chlordecone and malnutrition on immune response in rats.

Effect of Chlordecone (Cd) and malnutrition on total body and spleen weights, and plaque forming cells (PFC) were studied. Rats were fed on normal, calcium (Ca-D), protein (P-D) or Ca+P-deficient diets containing 0, 10 or 100 ppm of Cd for 2 or 4 weeks. High (95-100%) mortality was observed in malnourished rats treated with 100 ppm of Cd for 4 weeks. A slight decrease in body weight and an increase in spleen weight was observed in normal but not malnourished rats treated with 10 ppm of Cd for 4 weeks. PFC were significantly increased in both malnourished and Cd-treated rats. Similar increase in PFC was observed in rats fed on Ca-D but not P-D diet containing 10 or 100 ppm of Cd. Whereas, rats fed on Ca+P-D diet containing 100 ppm of Cd exhibited a significant decrease in PFC.

Animals↗
PubMed1993

Overdose of risperidone.

Risperidone is an investigational antipsychotic agent currently being tested in an international multicenter drug trial. We report the first case of a risperidone overdose in an apparent suicide attempt. This was without serious clinical side effects and manifested mainly as ECG abnormalities.

Adult↗
PubMed1993

The effect of irreversible image compression on diagnostic accuracy in thoracic imaging.

RATIONALE AND OBJECTIVES: Digital image compression reduces the storage requirements and network traffic on picture archiving and communications systems. Full-frame bit-allocation (FFBA) is an irreversible image-compression method based on the discrete cosine transform that provides for high compression ratios with a high degree of image fidelity. METHODS: One hundred twenty-two posteroanterior chest radiographs were obtained on patients in an ambulatory patient setting, including 30 cases of interstitial lung disease, 45 images containing combinations of lung nodules (N = 37) or mediastinal masses (N = 39), and 47 normal images containing none of the pathology for which we were testing. The images were digitized (nominal 2 K x 2 K x 12-bit resolution), printed on a 35 x 35-cm hard copy format, and compressed at an approximate compression ratio of 20:1. Observer performance tests were conducted with five radiologists using receiver operating characteristics analysis on digitized uncompressed and compressed hard copy images. RESULTS: There were no significant differences between the two display conditions for the detectability of any of the thoracic abnormalities. CONCLUSIONS: Our preliminary results suggest that irreversible image compression at ratios of 20:1 may be acceptable for use in digital thoracic imaging.

Algorithms↗
PubMed1993

QALYs for resource allocation: probably not and certainly not now.

Quality-adjusted life years (QALYs) have the attractive characteristic of combining morbidity and mortality into a single index which purports to measure the outcomes of health interventions. Their primary aim, when combined with cost, is to permit comparisons across candidate spending programs and thereby promote economic efficiency in the use of rationed funds. QALYs, in fact, comprise a family of measures with major differences in approach and many variations in construction, process and methods of measurement. A necessary unifying characteristic is the ethical assumption of utilitarianism. The paper examines the state of the art in the development of QALY measures. It concludes that they fall far short of requirements for their advocated use in resource allocation decisions. Furthermore, their demands on measurement for this purpose are such that it is unlikely that methodological problems can be solved.

Australia↗
PubMed1993

Mutational analysis of the p50 subunit of NF-kappa B and inhibition of NF-kappa B activity by trans-dominant p50 mutants.

The NF-kappa B family of DNA-binding proteins regulates the expression of many cellular and viral genes. Each of these proteins has an N-terminal region that is homologous to the c-Rel proto-oncogene product, and this Rel homology region defines both DNA binding and protein dimerization properties of the individual proteins. Most of the NF-kappa B family members have been shown to associate with themselves or with each other to form homodimers or heterodimers, and previous studies have shown that dimerization of NF-kappa B factors is necessary to provide a functional DNA binding domain. We have used site-directed mutagenesis to identify regions in the Rel homology domain of the p50/NF-kappa B protein that are important for DNA binding and protein dimerization. Our studies have identified mutations of p50 that interfere with DNA binding only and those that interfere with protein dimerization. Mutations of p50 which disrupt only DNA binding were still able to associate with other members of the NF-kappa B protein family. We demonstrate that such heterodimeric complexes inhibit transcriptional activation mediated in trans through a cis-acting kappa B motif; therefore, we have identified trans-dominant negative mutants of p50.

Cells, Cultured↗
PubMed1993

Descriptive and predictive validity of a high-risk alcoholism relapse model.

A major problem with alcoholism treatment is the high rate of early recidivism to drinking and re-admission for alcoholism treatment. The objective of this study was to retest a model or predict early (within 6 months) re-admission to alcoholism treatment using a second independent sample. Additionally, we compared a high-risk alcoholism relapse (HAR) model (defined by chronicity of heavy drinking, daily alcohol consumption and previous treatment history) with three previously defined alcoholism typologies for descriptive and predictive validity. Male alcoholics (N = 299) admitted for treatment at a Veterans Affairs inpatient treatment program were interviewed and then followed for 6 months after discharge. The HAR model identified 107 (35.8%) alcoholics at high-risk for relapse prior to discharge. Of the HAR group 61% were re-admitted within 6 months compared to 28% of the low-risk alcoholism relapse (LAR) group (OR = 4.0, 95% CI = 2.4-6.8). The HAR group was older with a lower socioeconomic status, fewer legal problems, more physical and mental health problems and decreased evidence of social support. The HAR model was more successful than were the typologies for predicting early relapse. The HAR model demonstrates descriptive and predictive validity and compares favorably to existing typology models.

Adult↗
PubMed1993

Morphological changes of myenteric neurons in the partially obstructed opossum esophagus.

We have previously described a model of partial esophageal obstruction which leads to hypertrophic and degenerative changes in the smooth muscle cells. In the present communication we describe changes occurring in the myenteric plexus including increased thickness, varicosities and irregular angulations of nerve fiber bundles. The perikarya of myenteric neurons in the obstructed esophagus showed elongated mitochondria, dilated cisternae of the endoplasmic reticulum and increased numbers of secondary lysosomes and multimembranous dense bodies. In myenteric axons, there was infiltration of Schwann cell subunit by collagen fibrils.

Animals↗
PubMed1992

Steroid therapy.

Explore the source record for details and available documents.

Adrenal Cortex Hormones↗
PubMed1992

Health checks on patients 75 years and over in Nottinghamshire after the new GP contract.

OBJECTIVE: To investigate annual health checks for patients of 75 years and over required by the 1990 contract for general practitioners. DESIGN: Visits to practices to collect information on how assessments were organised and carried out; completion of questionnaires for every patient who had been assessed in a sample month, using information provided by the practice records. SETTING: 20 general practices in one family health services authority. SUBJECTS: Patients of 75 years and over in 20 general practices. RESULTS: Three practices (15%) had not performed checks. Thirteen practices sent a letter to invite patients to undergo a check. Of these practices, seven followed up non-responders. Two practices visited patients' homes unannounced, and two did checks on an opportunistic basis only. Sixteen practices used a checklist. Sixteen practices involved their practice nurses; at eight of these, doctors also performed checks; in six practices the nurses undertaking the checks had no training in assessing old people. Ten practices assessed more than 75% of their old people in the first year of the new contract. Practices that did not follow up patients who had not responded to the invitation for assessment completed significantly fewer checks. During the sample month, 331 patients were assessed in the 17 practices. 204 new problems were discovered in 143 patients. Significantly more problems per patient were found in inner city areas. CONCLUSIONS: The way health checks were performed varied greatly, both in their organisation and the practices' attitudes. Many old people did not respond to letters asking if they wanted an assessment but very few refused one if followed up. Forty three per cent of those assessed had some unmet need. The number of new problems found per patient may reduce over the next few years if the assessments are successful. The need for annual assessment should be kept under review and adequate resources made available for the needs uncovered. Improved training for practice nurses in assessment is needed. Effectiveness of the checks must be monitored. If most unmet need falls in particular high risk groups it would seem sensible to modify the annual check to target these groups.

Aged↗
PubMed1992

Effect of H chain V region on complement activation by immobilized immune complexes.

Activation of C by immune complexes (IC) in tissues and the inflammatory consequences are major determinants in the pathogenesis of many autoimmune disorders. To assess the factors involved in C activation by such IC, we examined the binding of C components by chimeric IgG1 antibodies bound to immobilized Ag. We previously reported that alterations in the H chain V regions can affect the binding of first component of C (C1q) and a major breakdown product of the third C component (C3b) when otherwise identical antibodies were bound to immobilized (Tyr, Glu)-Ala-Lys. To evaluate C activation of these antibodies in well defined IC, we utilized a 9-amino acid peptide conjugated to BSA as Ag. The peptide:BSA conjugate was bound similarly by the two IgG1 antibodies which differed mainly in the CDR3 regions, but also in 9 other amino acids in the H chain V region. When soluble IC were prepared with the two antibodies, they activated C similarly. However, C activation by solid phase Ag:antibody complexes differed; we found that antibody 10B bound more C1q and C3b than antibody B11 did, unless the Ag was present at high density on the plates. These data suggest that the variable region differences affect C activation by these antibody when they are bound to immobilized Ag. Furthermore, these results underscore the differences in C activation by the same antibody depending upon whether the IC are free in solution or immobilized.

Amino Acid Sequence↗