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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 397 records · Page 22Linked to original sources
PubMed1997

Ultraviolet irradiation induces the production of multiple cytokines by human corneal cells.

PURPOSE: Ultraviolet (UV) irradiation exposure represents a significant environmental and occupational hazard that can cause acute and chronic inflammatory changes in the exposed cornea. Acute exposure to solar UV irradiation or to UV irradiation from such artificial sources as tanning lamps can result in severe pain and inflammation in the cornea. Chronic exposure to solar UV irradiation is associated with several external eye diseases including pterygium and squamous metaplasia or carcinoma. In the skin, inflammatory responses to UV exposure appear to be mediated by the release of inflammatory cytokines. The role of corneal-derived cytokines in UV-mediated corneal inflammation has not been established. In this study, the effect of UV exposure on the production of proinflammatory cytokines by corneal cells was examined. METHODS: Cultured human corneal stroma cells and whole human corneas received UV irradiation (10 to 100 mJ/cm2), and the production of the proinflammatory cytokines interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor alpha (TNF alpha) was measured by Northern blot analysis, enzyme-linked immunosorbent assay, cytokine bioassays, and immunohistochemical analysis. RESULTS: The results indicate that acute UV exposure leads to a significant increase in the production of IL-1, IL-6, IL-8, and TNF alpha in human corneal stroma cells. Similarly, acute UV irradiation of whole human corneas ex vivo induces a significant increase in the production of IL-1, IL-6, IL-8, and TNF alpha. CONCLUSIONS: Acute UV irradiation exposure results in the induction of cornea-derived proinflammatory cytokines. The local release of these proinflammatory cytokines by cells in the irradiated cornea may be responsible for UV-mediated corneal inflammation.

Blotting, Northern↗
PubMed1997

Incidence of health of the nation cancers by social class.

Using data from the Longitudinal Study social class patterns in the incidence of breast, lung and cervical cancer in women, and lung cancer in men, for the period 1976-89 were examined. At working ages, 15 to 64, there was very little difference in breast cancer incidence between women in non-manual and manual classes. At older ages the incidence was higher in women in non-manual classes than in those in manual classes. Cervical cancer incidence was considerably higher among younger women in manual than in non-manual classes and these differences were greatest in 1986-89. Among both younger and older men and women, strong class differentials in the incidence of lung cancer were evident in 1986-89. These findings indicate the need to target prevention strategies sensitively and to ensure equitable access to services.

Adolescent↗
PubMed1996

Analysis of three deletion breakpoints in Xp21.1 and the further localization of RP3.

The gene responsible for X-linked retinitis pigmentosa (xlRP) in Xp21.1 (RP3) was initially localized by deletion analysis to within a 150- to 170-kb region between the CYBB locus and the proximal deletion junction (BBJPROX) from a patient, BB, who suffered from Duchenne muscular dystrophy (DMD), McLeod syndrome, chronic granulomatous disease (CGD), and xlRP. This gene has recently been isolated and was found to be located outside and 400 kb proximal to the BB deletion. Further analysis of BBJPROX has identified the breakpoint junction sequence, showing that it occurs within an Alu repetitive element on the proximal side but with no significant homology to the distal sequence in dystrophin intron 30. Analysis of an overlapping deletion in patient NF, who suffered from DMD, CGD, and McLeod syndrome, shows that this deletion is within 4 kb but extends centromeric to BBJPROX, consistent with the location of RP3 outside the BB deletion region. A sequence with strong homology to a THE-1 transposon-like element was identified 7-13 kb from the proximal BB and NF breakpoints. These elements have been implicated in several highly unstable genomic regions. A third overlapping deletion, in a patient, SB, who suffered from CGD, McLeod syndrome, and xlRP, has here been shown to extend 380 kb proximal to the NF breakpoint, consistent with the finding that RP3 lies outside the BB deletion. This deletion has now been shown to disrupt the RP3 (RPGR) gene. The reason for the retinitis pigmentosa phenotype in patient BB remains unclear, but the most likely explanations include a long-range chromosomal position effect, a small secondary rearrangement, and the presence of a coincident autosomal form of retinitis pigmentosa.

Base Sequence↗
PubMed1996

Reduction in numerical synapse density in chick (Gallus domesticus) dorsal hippocampus following transient cerebral ischaemia.

Transient forebrain ischaemia was induced by a two-vessel occlusion method in the domestic chick. One week post-surgery, hippocampal tissue was processed for electron microscopy and synapse density assessed using the disector technique. Hippocampal volume was estimated using image analysis of serial coronal cryostat sections. The density of asymmetric synapses was significantly reduced (27%; P < 0.005) in ischaemic chicks. This appears to be a real reduction as hippocampal volume was not significantly decreased.

Animals↗
PubMed1996

CD34-deficient mice have reduced eosinophil accumulation after allergen exposure and show a novel crossreactive 90-kD protein.

CD34 is expressed on the surface of hematopoietic stem/progenitor cells, stromal cells, and on the surface of high-endothelial venules (HEV). CD34 binds L-selectin, an adhesion molecule important for leukocyte rolling on venules and lymphocyte homing to peripheral lymph nodes (PLN). We generated CD34-deficient mutant animals through the use of homologous recombination. Wild-type and mutant animals showed no differences in lymphocyte binding to PLN HEV, in leukocyte rolling on venules or homing to PLN, in neutrophil extravasation into peritoneum in response to inflammatory stimulus, nor in delayed type hypersensitivity. Anti-L-selectin monoclonal antibody (MEL-14) also inhibited these immune responses similarly in both CD34-deficient and wild-type mice. However, eosinophil accumulation in the lung after inhalation of a model allergen, ovalbumin, is several-fold lower in mutant mice. We found no abnormalities in hematopoiesis in adult mice and interactions between mutant progenitor cells and a stromal cell line in vitro were normal. No differences existed in the recovery of progenitor cells after 5-fluorouracil treatment, nor in the mobilization of progenitor cells after granulocyte colony-stimulating factor treatment compared with wild-type animals. Surprisingly, although CD34 was not expressed in these mice, a portion of its 90-kD band crossreactive with MECA79 remained after Western blot. Thus, we have identified an additional molecule(s) that might be involved in leukocyte trafficking. These results indicate that CD34 plays an important role in eosinophil trafficking into the lung.

Allergens↗
PubMed1996

Mammography screening: an incremental cost effectiveness analysis of double versus single reading of mammograms.

OBJECTIVE: To compare mammography reading by one radiologist with independent reading by two radiologists. DESIGN: An observational non-randomised trial at St Margaret's Hospital, Epping. SUBJECTS: 33 734 consecutive attenders for breast screening in the main trial and a sample of 132 attenders for assessment who provided data on private costs. INTERVENTIONS: Three reporting policies were compared: single reading, consensus double reading, and non-consensus double reading. MAIN OUTCOME MEASURES: Numbers of cancers detected, recall rates, screening and assessment costs, and cost effectiveness ratios. RESULTS: A policy of double reading followed by consensus detected an additional nine cancers per 10 000 women screened (95% confidence interval 5 to 13) compared with single reading. A non-consensus double reading policy detected an additional 10 cancers per 10 000 women screened (95% confidence interval 6 to 14). The difference in numbers of cancers detected between the consensus and non-consensus double reading policies was not significant (95% confidence interval -0.2 to 2.2). The proportion of women recalled for assessment after consensus double reading was significantly lower than after single reading (difference 2.7%; 95% confidence interval 2.4% to 3.0%). The recall rate with the non-consensus policy was significantly higher than with single reading (difference 3.0%; 2.5% to 3.5%). Consensus double reading cost less than single reading (saving 4853 pounds per 10 000 women screened). Non-consensus double reading cost more than single reading (difference 19 259 pounds per 10 000 women screened). CONCLUSIONS: In the screening unit studied a consensus double reading policy was more effective and less costly than a single reading policy.

Breast Neoplasms↗
PubMed1996

Right ventricular systolic function in adolescents and young adults after Mustard operation for transposition of the great arteries.

This study evaluates long-term ( > 10 years since surgery) right ventricular (RV) systolic function in patients who had previously undergone intraatrial baffle surgery for transposition of the great arteries. Studies suggest these patients are clinically stable and lead satisfactory lifestyles, but long-term ventricular performance is not known. Radionuclide angiocardiography was used to estimate RV ejection fraction in 58 patients a mean of 14 years after the Mustard operation. Repeat studies were performed in 32 patients. The absolute RV ejection fraction of 0.53 +/- 0.10 in our patients did not differ from normal values. Nine patients had a value < 0.42, placing them > 2 SDs below normal. Repeat RV ejection fraction decreased from 0.54 +/- 0.11 to 0.51 +/- 0.11 (p < 0.1) in 32 patients, and > 0.10 in 6. Thus, RV ejection fraction was abnormal in 9 of 58 patients (16%) evaluated > 10 years after a Mustard operation. Repeat studies demonstrate worsening in at least 6 of 32 patients (19%). These postoperative Mustard patients require continued evaluation, even in the absence of overt symptomatology.

Adolescent↗
PubMed1996

Familial dementia with swollen achromatic neurons and corticobasal inclusion bodies: a clinical and pathological study.

Clinical, pathological and molecular genetic data are presented in two families in which 15 individuals have developed a progressive dementia. Clinical details are available in 10 individuals, neuropathological data in 2. Affected individuals presented between the ages of 43 and 59 years with personality change or memory loss. All individuals developed a progressive dementia with features of frontal lobe dysfunction. Affected individuals commonly developed additional features which included dysphasia, parkinsonism, limb clumsiness and disequilibrium. Duration to death was between 3 and 13 years. Pathological examination of one individual from each family revealed a combination of features not previously described in a familial dementia. Macroscopic examination revealed lobar atrophy. Microscopy revealed neuronal loss and gliosis with swollen achromatic neurons in the cortex and corticobasal inclusion bodies in the substantia nigra. On clinical assessment these families have many features of Pick's disease but pathological examination reveals features more suggestive of corticobasal degeneration.

Adult↗
PubMed1996

Infinitesimal risk as public health crisis: news media coverage of a doctor-patient HIV contact tracing investigation.

Among the most prominent health or medical stories covered in 1994 by the Australian news media was that concerning an HIV positive hospital obstetrician and the attempt by the New South Wales Health Department to trace and test 149 women on whom he had operated. All press and television coverage of the issue was reviewed. The surface news narrative of the search for missing, "innocent" mothers potentially infected with a deadly and infectious illness is shown to serve as a "hard news" pretext enabling a wider major discourse to operate about a health system accused as being captive to gay and civil libertarian politics, allowing "guilty" doctors at high risk of HIV to endanger "innocent" patients. Expert consensus held that the women were at "infinitesimal risk" of acquiring HIV. However, media accounts of the investigation all but belied this, illustrating that the news media's framing of risk has more to do with its reproduction of moral outrage components than with "scientific" notions of calculable risk.

Attitude to Health↗
PubMed1996

The reliability of the Alcohol Timeline Followback when administered by telephone and by computer.

The Alcohol Timeline Followback (TLFB) has been shown to be a psychometrically sound assessment instrument for obtaining retrospective daily estimates of alcohol consumption. These evaluations, however, have been limited to face-to-face paper-and-pencil interviews. As use of the TLFB method has increased, investigators have reported using the method to collect follow-up data by telephone. Also, as with many assessment instruments, a computerized version of the TLFB method has been developed. The psychometric characteristics of the TLFB method under these administration conditions have not been evaluated. This paper presents results from two studies showing that the Alcohol TLFB method can obtain reliable drinking data when administered over the telephone and by computer.

Adult↗
PubMed1996

Interferon-gamma mediates long-term persistent Chlamydia psittaci infection in vitro.

The long-term anti-chlamydial effects of recombinant ovine interferon gamma (rOvIFN-gamma) were studied in ovine ST-6 fibroblasts infected with the S26/3 strain of Chlamydia psittaci. Chlamydial multiplication was assessed by enzyme-linked immunosorbent assay analysis of supernate lipopolysaccharide, titration of inclusion-forming units in culture supernates, and enumeration of inclusion bodies in cultured cells at 7-day intervals. Concentrations of 250 and 1000 U/ml of rOvIFN-gamma resulted in a microbistatic inhibition of C. psittaci growth, which appeared to become microbicidal when rOvIFN-gamma was maintained in the cultures for 14 days or more. There were no signs of C. psittaci multiplication when cultures were maintained in 25 or 100 U/ml of rOvIFN-gamma. However, subsequent removal of rOvIFN-gamma from these cultures resulted in a re-emergence of viable, infectious chlamydiae, which eventually killed all the fibroblasts. This re-emergence was more rapid in cultures initially treated with 25 U/ml of rOvIFN-gamma than in those treated with 100 U/ml.

Abortion, Veterinary↗
PubMed1996

Visual prognosis of multifocal choroiditis, punctate inner choroidopathy, and the diffuse subretinal fibrosis syndrome.

PURPOSE: To characterize the visual prognosis of patients with multifocal choroiditis and panuveitis (MCP), punctate inner choroidopathy (PIC), and the diffuse subretinal fibrosis (DSF) syndrome. METHODS: Forty-one patients with MCP, 16 with PIC, and 5 with DSF syndrome were evaluated. The mean follow-up was approximately 39 months for patients with MCP, 51 months for patients with PIC, and 59 months for patients with DSF syndrome. Complete ophthalmic examinations were performed, and photofiles were reviewed. RESULTS: The final average visual acuity for patients with MCP was 20/50. Forty-five of the 68 involved eyes (66%) had 20/40 visual acuity or better. Choroidal neovascularization (CNV) developed within choroiditis lesions in 22 (19 patients) of 68 eyes, causing visual acuity poorer than 20/50 in 14 eyes. The final average visual acuity in patients with PIC was 20/39; 23 (77%) of the 30 involved eyes had visual acuity of 20/40 or better. Six of the seven eyes with 20/50 or poorer vision had CNV. Six other eyes had CNV within the macula that regressed spontaneously with good resultant vision. Seven of the ten involved eyes with DSF syndrome had 20/200 or poorer vision. Poor vision was due to fibrosis and atrophy within the macula. CONCLUSION: Most patients with MCP and PIC retained visual acuity of 20/40 or better. In nearly one third of patients with MCP and PIC, CNV developed. Severe visual loss in these diseases was usually due to subfoveal CNV. Patients with DSF syndrome had a poor prognosis due to fibrosis and atrophy involving the macula.

Adrenal Cortex Hormones↗