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Biomedical subjects

J Evans

Publications and source records attributed to J Evans.

At least 217 records · Page 12Linked to original sources
PubMed1997

Retinal vascular network architecture in low-birth-weight men.

BACKGROUND: Low birth weight is associated with hypertension and increased cardiovascular mortality, but the mechanism of this association is not known. Hypertension is accompanied by abnormalities of the microvasculature including rarefaction. OBJECTIVE: To test the hypothesis that low birth weight is associated with an alteration in microvascular architecture. DESIGN: A stratified random sample of 100 men aged 64-74 years was selected from a cohort of men whose birth weights were known. They were of relatively high or low birth weight ('high' > or = 3700 g, 'low' < or = 3200 g) and high or low systolic blood pressure (high > or = 160 mmHg, low < or = 140 mmHg). METHODS: Retinal arteriolar geometry was defined in terms of arteriolar bifurcation angles and junction exponents (a measure of the relative diameters of parent and daughter vessels), measured from photographic diapositives using operator-directed image analysis. RESULTS: Members of low-birth-weight groups had significantly narrower bifurcation angles than did members of high-birth-weight groups (74 +/- 1 degree versus 78 +/- 1 degree, P= 0.017 by analysis of variance). There was no significant difference between angles in members of groups with high and low blood pressures. Neither birth weight nor blood pressure grouping affected junction exponents. CONCLUSIONS: Narrower bifurcation angles are associated with increased circulatory energy costs and may be related to a lower than normal microvascular density. Our finding of differences in retinal microvascular architecture might reflect a persistent alteration in vascular architecture as a result of an impairment of foetal development and could provide a mechanistic link between low birth weight and subsequently increased cardiovascular risk.

Aged↗
PubMed1997

Simple sequence repeats in watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai).

Simple sequence repeat length polymorphisms were utilized to examine genetic relatedness among accessions of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai). A size-fractionated TaqI genomic library was screened for the occurrence of dimer and trimer simple sequence repeats (SSRs). A total of 96 (0.53%) SSR-bearing clones were identified and the inserts from 50 of these were sequenced. The dinucleotide repeats (CT)n and (GA)n accounted for 82% of the SSRs sequenced. PCR primer pairs flanking seven SSR loci were used to amplify SSRs from 32 morphologically variable watermelon genotypes from Africa, Europe, Asia, and Mexico and a single accession of Citrullus colocynthis from Chad. Cluster analysis of SSR length polymorphisms delineated 4 groups at the 25% level of genetic similarity. The largest group contained C. lanatus var. lanatus accessions. The second largest group contained only wild and cultivated "citron"-type or C. lanatus var. citroides accessions. The third group contained an accession tentatively identified as C. lanatus var. lanatus but which perhaps is a hybrid between C. lanatus var. lanatus and C. lanatus var. citroides. The fourth group consisted of a single accession identified as C. colocynthis. "Egusi"-type watermelons from Nigeria grouped with C. lanatus var. lanatus. The use of SSRs for watermelon germplasm characterization and genetic diversity studies is discussed.

DNA, Plant↗
PubMed1997

Characteristics of breast carcinomas missed by screening radiologists.

PURPOSE: To determine whether breast cancers missed at screening mammography have distinguishing characteristics from those of detected cancers. MATERIALS AND METHODS: The mammograms of 146 women with mammographically identifiable breast cancer were viewed independently by two radiologists who were blinded as to whether the cancer had been missed or detected (group 1 lesions, missed cancers; group 2 lesions, detected cancers) at screening. The mammographic lesions were characterized as to location, size, density, type, and visibility on two views. RESULTS: A significant difference between missed and detected cancers was found for diameter (P = .03), number of views (P < .0017), and density (P = .0007). Stepwise multivariable logistic regression showed that density (P = .01) and the number of views (P = .03) but not diameter (P = .27) were independently significant in distinguishing the groups. No statistically significant difference was found between the two groups for lesion type (P = .32 for reader 1 and P = .27 for reader 2) or location (P = .86 for reader 1 and P > .96 for reader 2). CONCLUSION: Missed cancers were statistically significantly lower in density and more often seen on only one of two views than detected cancers.

Adult↗
PubMed1997

Growth hormone, IGF-I, and exercise effects on non-weight-bearing fast muscles of hypophysectomized rats.

The effects of growth hormone (GH) or insulin-like growth factor I (IGF-I) with or without exercise (ladder climbing) in countering the effects of unweighting on fast muscles of hypophysectomized rats during 10 days of hindlimb suspension were determined. Compared with untreated suspended rats, muscle weights were 16-29% larger in GH-treated and 5-15% larger in IGF-I-treated suspended rats. Exercise alone had no effect on muscle weights. Compared with ambulatory control, the medial gastrocnemius weight in suspended, exercised rats was larger after GH treatment and maintained with IGF-I treatment. The combination of GH or IGF-I plus exercise in suspended rats resulted in an increase in size of each predominant fiber type, i.e., types I, I + IIa and IIa + IIx, in the medial gastrocnemius compared with untreated suspended rats. Normal ambulation or exercise during suspension increased the proportion of fibers expressing embryonic myosin heavy chain in hypophysectomized rats. The phenotype of the medial gastrocnemius was minimally affected by GH, IGF-I, and/or exercise. These results show that there is an IGF-I, as well as a GH, and exercise interactive effect in maintaining medial gastrocnemius fiber size in suspended hypophysectomized rats.

Animals↗
PubMed1997

Inhibition of ERK activation attenuates endothelin-stimulated airway smooth muscle cell proliferation.

Endothelin is a small peptide that is a potent bronchoconstrictor, mitogen for airway smooth muscle (ASM), and is believed to be involved in the pathogenesis of asthma. To understand how endothelin stimulates the proliferation of ASM cells in culture, we evaluated the relationship between mitogen activated protein (MAP) kinase activation and cell proliferation. Endothelin is a potent stimulator of the extracellular regulated kinase 2 (ERK2) subgroup of MAP kinases, and ERK2 activation was tightly correlated with the proliferation of rat ASM cells. PD98059, a small molecule inhibitor of MEK (MAP or ERK kinase) was used to establish the role of ERK2 activation in the endothelin-stimulated signal transduction pathway leading to cell proliferation. While PD98059 significantly inhibited the ability of endothelin to activate ERK, the drug did not appear to effect the catalytic activity of an activated MEK mutant, or ERK in vitro. The data suggest that the mechanism of PD98059 inhibition of the ERK2 pathway in ASM cells may involve inhibition of MEK activation. The endothelin signal transduction pathway that culminates in ERK2 activation was dependent on protein kinase C (PKC), since depletion of PKC significantly inhibited the ability of endothelin to activate ERK2. Taken together, the data imply that activation of ERK is a critical endpoint in the endothelin signal transduction pathway since inhibition of this kinase inhibits endothelin-induced ASM cell proliferation.

Animals↗
PubMed1997

Direct assessment of functional status in older patients with schizophrenia.

OBJECTIVE: There has been a growing trend in medicine to evaluate the impact of illness on functional abilities. Such studies typically rely on the patient's or caregiver's report. The goal of this study was to assess directly the functional capacity of psychiatric patients, especially older ones. METHOD: The subjects were 55 outpatients with schizophrenia and 72 normal persons ranging in age from 45 to 86 years. The subjects were administered the Direct Assessment of Functional Status Scale, which assess behaviour during simulated daily activity tasks in the areas of time orientation, communication, transportation, finance, shopping, grooming, and eating. RESULTS: The patients with schizophrenia had significantly greater disability than the normal subjects according to total scale scores as well as the communication, transportation, finance, and shopping subscale scores. Global cognitive status was the best predictor of total scale score. CONCLUSIONS: The Direct Assessment of Functional Status Scale is a promising instrument for functional assessment in outpatients with schizophrenia.

Activities of Daily Living↗
PubMed1997

Assessment of the perceived need for a psychiatric service to a magistrates' court.

One approach to diversion from custody of mentally disordered offenders is to provide a psychiatric liaison service to local magistrates' courts. We aimed to establish whether such a scheme was needed locally. Questionnaires for the bench, defence solicitors and bail information officers, enquiring as to the perceived need for a psychiatric assessment, social service care and specialist bail provision, were distributed for all those appearing in a magistrates' court who had been held overnight in police custody. Responses were received for 223 individuals. An immediate psychiatric report was considered necessary for 4.9% of cases. In 2.2% of cases it was thought that remand in custody could have been avoided if such an opinion had been available. In 8% of cases it was thought that remand in custody could have been avoided if specialist bail provision were available. We conclude that availability of a specialist bail provision would lead to a greater number of diversions from custody than providing a psychiatric service to this magistrates' court.

Civil Rights↗
PubMed1997

Edwardsiellosis in wild striped bass from the Chesapeake Bay.

The first epizootic of edwardsiellosis, caused by Edwardsiella tarda, is described. The epizootic occurred in the Chesapeake Bay, Maryland (USA) during the summer and autumn of 1994, and affected wild adult striped bass (Morone saxatilis). Clinical signs included numerous irregular coalescing hemorrhagic ulcers on the body and fins that were distinctly malodorous. Internally, the body cavity was filled with abundant yellowish or sanguinous mucoid fluid, and the visceral organs had multiple tiny white foci. The intestines contained thick white opaque mucus. Histopathological lesions included ulcerative dermatitis, cardiac endothelial hyperplasia, and necrotic foci and granulomata in multiple organs. A bacterium isolated in pure culture was characterized taxonomically and serologically as the wild-type or classical biotype of E. tarda: In infectivity trials, it was pathogenic for striped bass, gilthead seabream (Sparus aurata), and turbot (Scophthalmus maximus) with an LD50 of about 10(5) cells; however, the isolate was non-virulent for mice (LD50 > 10(8) cells). The isolate also was resistant to the bacteriolytic activity of normal fish skin mucus.

Animals↗