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Biomedical subjects

J Stone

Publications and source records attributed to J Stone.

At least 55 records · Page 3Linked to original sources
PubMed2001

Divry-Van Bogaert syndrome in a female: relationship to Sneddon's syndrome and radiographic appearances.

A 28-year-old woman presented with generalised livedo reticularis, dementia, epilepsy, and pyramidal and extrapyramidal signs. Multiple focal infarcts were seen on MRI. Angiography demonstrated widespread cerebromeningeal angiomatosis with multiple small and medium size arterial occlusions. A lifelong personal and family history of mental handicap in the absence of anticardiolipin antibodies suggests Divry-Van Bogaert syndrome, not previously been reported in a female. Similarities to Sneddon's syndrome are discussed.

Adult↗
PubMed2001

Effects of exposure time, material type, and granular pesticide on glove contamination.

Chemical-resistant gloves are recommended for pesticide applicators to reduce their exposure to agricultural chemicals. In this research, three chemical-resistant glove materials-nitrile, neoprene, and barrier laminate-were studied in relation to contamination with granular terbufos and tefluthrin. Surfaces of specimens backed with alpha cellulose were contaminated with 300 mg of either granular terbufos or tefluthrin for 1-, 2-, 4-, 8-, 16-, and 24-h time periods in petri dishes in the laboratory. Residues were extracted using ethyl acetate for terbufos and iso-octane for tefluthrin in test tubes for 24 h. Analysis of extracts by gas chromatograph and statistical analysis of the data showed that contamination levels varied with the time of exposure, material type, and pesticide used. Pesticide was not detected in the alpha cellulose even after 24 h contamination time. A linear relationship was found between contamination level and exposure time for terbufos in the three materials, with longer exposure times causing higher contamination levels. Contamination of nitrile was significantly less than neoprene or barrier laminate. Exposed glove materials contained higher levels of contamination of terbufos than tefluthrin.

Chromatography, Gas↗
PubMed2001

Mammographic densities as a marker of human breast cancer risk and their use in chemoprevention.

Differences in the parenchymal pattern of the breast on mammography reflect differences in the amounts of stromal, epithelial, and fat tissue present in the breast. Stroma and epithelium are radiologically dense, whereas fat is lucent. Extensive areas of mammographically dense breast tissue are strongly associated with an increased risk of breast cancer. A variety of interventions, including gonadotropin-releasing hormone inhibitor, tamoxifen, stopping hormone replacement therapy (HRT), and adopting a low-fat, high-carbohydrate diet, all influence the tissue composition of the breast and reduce mammographic densities. Of the interventions examined to date, only tamoxifen has been shown to reduce the incidence of breast cancer, at least in the short term. Conversely, HRT, which increases density, also increases risk of breast cancer. These results suggest that mammographic density may be a short-term marker of the effect on the breast of potential preventive interventions for breast cancer.

Antineoplastic Agents, Hormonal↗
PubMed2001

The role of perinatal stress in simplex retinitis pigmentosa: evidence from surveys in Australia and the United States.

BACKGROUND: In experimental models of several forms of human retinitis pigmentosa (RP) the dystrophy begins in the neonatal period, during a "critical period" in which photoreceptors are sensitive to hypoxia. We performed a study to test whether perinatal stress is associated with human RP, particularly in simplex (nonfamilial) cases. METHODS: Two surveys were carried out in 1999. In one, Australians with RP were surveyed for information on whether they had experienced stress at birth and whether any members of their family had RP. In the other, the diagnostic type and inheritance patterns of a group of patients with RP seen at a university-affiliated eye institute in Los Angeles between 1997 and 1999 were established as part of their clinical assessment. In neither cohort was the RP part of a syndrome. RESULTS: After entry criteria were applied, there were 293 cases (of a total of 446 replies) available for analysis from the Australian survey and 119 cases (after exclusion of 229 cases with incomplete data) from the US survey. A total of 52.2% and 53.8% of the cases respectively were simplex. Perinatal stress was reported by about 15% of the respondents with familial RP (15.0% in the Australian cohort and 14.5% in the US cohort), compared with 30% of those with simplex RP (27.4% and 29.7% respectively), a significant difference (p < 0.05). In the Australian cohort four forms of stress--cyanosis, difficult presentation, prematurity and a perinatal period of intensive care--were reported more than twice as often by respondents in the simplex group than those in the familial group. For only one factor, cyanosis, was the difference between the two groups significant (chi2 test, p = 0.01). In the US cohort no single form of stress was significantly related to simplex RP. INTERPRETATION: Our findings support the hypothesis that perinatal stress is associated with simplex RP in a minority of cases. Larger cohorts need to be studied to test whether perinatal stress can interact with predisposing genes in the genesis of some forms of RP.

Australia↗
PubMed2001

A direct determination of thymidine triphosphate concentrations without dephosphorylation in peripheral blood mononuclear cells by LC/MS/MS.

A rapid, sensitive and specific analytical method with minimal sample preparation for the measurement of thymidine triphosphate (TTP) in peripheral blood mononuclear cells (PBMC) by LC/MS/MS has been developed. PBMC were separated from whole blood or buffy coat. The analyte and internal standard were extracted from PBMC with 70% methanol (pH 7.2). These extracts after centrifugation were directly injected onto LC/MS/MS without need for any further sample preparation. The calibration curve was linear over the range 0.8-800 ng/ml. Mean inter- and intra-assay coefficients of variation (CVs) over the range of the standard curve were less than 10%. The overall recovery of TTP was 103.5%.

Calibration↗
PubMed2001

Scleroderma "en coup de sabre": pathological evidence of intracerebral inflammation.

Linear scleroderma "en coup de sabre" (LScs) is associated with neurological complications, the pathogenesis of which is uncertain. A 27 year old woman is reported on who developed epilepsy and focal neurological signs in association with LScs. Brain MRI demonstrated predominantly ipsilateral relapsing and remitting grey and white matter lesions. Analysis of CSF and pathology obtained at brain biopsy provides evidence of an inflammatory process which may be amenable to immunosuppressive treatment.

Adult↗
PubMed2001

Central nervous system vasculitis as a complication of refractory dermatomyositis.

We describe a 47-year-old woman with refractory dermatomyositis (DM) who developed progressive cognitive dysfunction. Magnetic resonance imaging showed a large cerebral infarction, and the diagnosis of central nervous system (CNS) vasculitis was confirmed by both angiogram and brain biopsy. Her DM and CNS vasculitis responded promptly to the institution of daily cyclophosphamide, and her previously refractory disease entered remission.

Brain↗