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Biomedical subjects

H Wilson

Publications and source records attributed to H Wilson.

At least 37 records · Page 2Linked to original sources
PubMed2000

A two-stage, genome-wide screen for susceptibility loci in primary Raynaud's phenomenon.

OBJECTIVE: To identify chromosomal regions containing genes involved in the susceptibility to primary Raynaud's phenomenon (RP). METHODS: Six extended families with multiple individuals affected with primary RP (n = 37) were examined for linkage in a 2-stage, whole-genome screen, using a total of 298 microsatellite markers. RESULTS: Multipoint, nonparametric linkage analysis identified 5 areas of possible linkage, with a nominal level of significance of P < or = 0.05. Analysis of a finer map of markers in these regions defined the regions of linkage as 21.4 cM on 6q13-6q23.3 (D6S261; P = 0.0004), 10.2 cM on 7p22-7p15 (D7S664; P = 0.014), 1.6 cM on 9p23-9p22 (D9S156; P = 0.0075), 5.1 cM on 17p13.1-17p12 (D17S1791; P = 0.036), and 11.8 cM on Xp11.4-Xp11.23 (DXS8054; P = 0.006). Three potential candidate genes map to these regions: the beta subunit of the muscle acetylcholine receptor and the serotonin 1B and 1E receptors. CONCLUSION: These results provide evidence of the presence and location of genes that are involved in the genetic susceptibility to primary RP.

Adolescent↗
PubMed2000

Cigarette smoking and epithelial ovarian cancer by histologic type.

OBJECTIVE: To examine cigarette smoking as a risk factor for different types of epithelial ovarian cancer. METHODS: We used data from the Cancer and Steroid Hormone Study, a multicenter, population-based, case control investigation. Cases were 447 women aged 20-54 years with diagnoses of epithelial ovarian cancer. Controls were 3868 women selected by random-digit dialing. Conditional logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs) as estimators of the relative risk of ovarian cancer. With age and study site as conditioning variables, OR point estimates were additionally adjusted for parity and use of oral contraceptives. RESULTS: The OR of mucinous epithelial ovarian cancer for women who had ever smoked was 2.3 (95% CI 1.4, 3.9) and for current smokers was 2.9 (95% CI 1.7, 4.9). The OR of mucinous tumors for current smokers was significantly elevated regardless of years since first cigarette or age at which women first smoked. The OR of mucinous tumors for current smokers increased slightly as cumulative pack-years of smoking increased, although the trend was not significant. Similar patterns of elevated risk were not observed among serous, endometrioid, or other histologic types. Odds ratio point estimates for former smokers were not significantly elevated for any histologic type. CONCLUSION: Current cigarette smoking was a risk factor for mucinous epithelial ovarian cancer, but not other histologic types.

Adult↗
PubMed2000

The prevalence of polycystic ovaries in women with a history of gestational diabetes.

OBJECTIVE: Women with a history of gestational diabetes mellitus (GDM) and women with polycystic ovary syndrome (PCOS) both demonstrate abnormalities in insulin action and secretion, and both are at increased risk of developing type 2 diabetes. To determine whether these similarities reflect a common pathophysiological basis, we examined the prevalence of ultrasound-based polycystic ovarian morphology in a large multiethnic group of women with a history of GDM and a group of women who had normal glucose tolerance during pregnancy. PATIENTS AND DESIGN: We studied 91 women with previous GDM (48 European, 20 South Asian, 10 Afro-Caribbean and 13 of other or mixed ethnicity) and 73 normoglycaemic control women (56 European, one South Asian, 14 Afro-Caribbean and two of other or mixed ethnicity), a median (interquartile range) of 20 (11-36) and 29 (17-49) months postpartum, respectively. A detailed history was taken, and the prevalence of PCO morphology on ultrasound scan was assessed. Fasting lipids, insulin, glucose status, gonadotrophins and testosterone were measured. Estimates of beta-cell function (%B) and insulin sensitivity (%S) were derived using the HOMA algorithm. RESULTS: Women with previous GDM had higher fasting glucose (5.4 (4. 8-6.0) vs. 4.7 (4.4-5.0) mmol/l, P<0.0001) and features reminiscent of syndrome X: higher BMI (26.4 (22.8-31.4) vs. 23.8 (21. 0-27.5) kg/m2, P = 0.002), waist/hip ratio (0.82 (0.79-0.88) vs. 0. 77 (0.73-0.81), P<0.0001), fasting insulin (165 (68-299) vs. 54 (24-156) pmol/l, P<0.0001), triglycerides (1.1 (0.8-1.6) vs. 0.8 (0.6-1.1) mmol/l, P<0.0001) and lower insulin sensitivity (%S) (27 (16-62) vs. 86 (34-139)%, P<0.0001) compared to control women. The prevalence of PCO was higher in the previous GDM group than in the control subjects (47/91 (52%) vs. 20/73 (27%), chi2 = 9.86, P = 0. 002 overall, odds ratio 2.7, P = 0.007 by logistic regression allowing for ethnicity). There was no difference in any metabolic parameter between the post-GDM PCO group and the post-GDM normal ovaries group, but irregular cycles were more prevalent in the PCO group (22/47 (47%) vs. 9/44 (21%), chi2 = 7.03, P = 0.008). CONCLUSIONS: We found a higher prevalence of polycystic ovarian morphology in women with a history of gestational diabetes. Among the women with previous gestational diabetes, irregular cycles were more prevalent in the PCO group than in the women with normal ovarian morphology, but no other differences in endocrine or metabolic parameters were detected. These findings confirm an association between PCO and gestational diabetes and suggest that women with gestational diabetes display metabolic abnormalities irrespective of ovarian morphology.

Blood Glucose↗
PubMed2000

Scorpion alpha and alpha-like toxins differentially interact with sodium channels in mammalian CNS and periphery.

Scorpion alpha-toxins from Leiurus quinquestriatus hebraeus, LqhII and LqhIII, are similarly toxic to mice when administered by a subcutaneous route, but in mouse brain LqhII is 25-fold more toxic. Examination of the two toxins effects in central nervous system (CNS), peripheral preparations and expressed sodium channels revealed the basis for their differential toxicity. In rat brain synaptosomes, LqhII binds with high affinity, whereas LqhIII competes only at high concentration for LqhII-binding sites in a voltage-dependent manner. LqhII strongly inhibits sodium current inactivation of brain rBII subtype expressed in HEK293 cells, whereas LqhIII is weakly active at 2 microM, suggesting that LqhIII affects sodium channel subtypes other than rBII in the brain. In the periphery, both toxins inhibit tetrodotoxin-sensitive sodium current inactivation in dorsal root ganglion neurons, and are strongly active directly on the muscle and on expressed muI channels. Only LqhII, however, induced repetitive end-plate potentials in mouse phrenic nerve-hemidiaphragm muscle preparation by direct effect on the motor nerve. Thus, rBII and sodium channel subtypes expressed in peripheral nervous system (PNS) serve as the main targets for LqhII but are mostly not sensitive to LqhIII. Toxicity of both toxins in periphery may be attributed to the direct effect on muscle. Our data elucidate, for the first time, how different toxins affect mammalian central and peripheral excitable cells, and reveal unexpected subtype specificity of toxins that interact with receptor site 3.

Animals↗
PubMed2000

Angiogenesis in the human corpus luteum: localization and changes in angiopoietins, tie-2, and vascular endothelial growth factor messenger ribonucleic acid.

In the menstrual cycle, extensive angiogenesis accompanies luteinization. During luteolysis, endothelial cells die, whereas in a conceptual cycle, the corpus luteum (CL) persists, and endothelial cell survival is extended. A main stimulator for angiogenesis is vascular endothelial growth factor (VEGF), while the angiopoietins (Ang-1 and Ang-2) may be important modulators. The aim of this study was to investigate the localization of Ang-1, Ang-2, their common receptor Tie-2, and VEGF messenger ribonucleic acid (mRNA) at the different stages of the functional luteal phase and after rescue by hCG. Ang-1 mRNA was uniformly expressed at a low level throughout the CL. The signal was highest during the early luteal phase. In contrast, Ang-2 mRNA expression was localized strongly to individual granulosa and thecal luteal and endothelial cells. Administration of hCG was associated with an increase in the Ang-2 mRNA area of expression and grain density in individual luteal and endothelial cells. The Tie-2 receptor mRNA was localized in endothelial cells, and the area of expression was highest during the early luteal phase and during luteal rescue. VEGF mRNA was found exclusively in granulosa luteal cells, and the area of expression was highest in corpora lutea during simulated pregnancy. These results begin to characterize the molecular regulation of the divergent processes involved in luteal angiogenesis during luteinization, luteolysis, and rescue in the human and imply that the angiopoietins are involved during the initial angiogenic phase and in luteal rescue.

Adult↗
PubMed2000

Providing care to patients with pancreatic cancer: a retrospective chart review.

Pancreatic cancer may be considered rare, yet in Canada it is the fourth leading cause of death by cancer in the elderly. This study was conducted in a large tertiary centre to determine the symptoms experienced by patients and the response by health professionals in providing supportive care. This paper reports the results of a retrospective review of health records from patients diagnosed with pancreatic cancer (n = 99). Results indicate that pain, nausea, vomiting, and anorexia were frequently reported. There was a lack of consistency in the documentation of nursing care and little evidence of an organized, planned approach for care delivery. The role of the interdisciplinary health care team and its members in managing this devastating disease and its impact on patient quality of life was difficult to ascertain. The development of an integrated approach to the care of patients with pancreatic cancer is presented.

Aged↗
PubMed1999

Androgen actions on central serotonin neurotransmission: relevance for mood, mental state and memory.

Sex steroids exert potent effects on mood and mental state in the human. Our previous experimental findings in female rats suggest that these effects may be mediated, in part, by the action of estrogen on the 5-hydroxytryptamine2A receptor (5-HT(2A)R) and serotonin transporter (SERT) in brain. Here we review our recent findings on the effect of acute (approximately 32 h) testosterone manipulation on central 5-HT(2A)R and SERT in male rats. Castration decreased while testosterone or estrogen, but not 5alpha-dihydrotestosterone (5alpha-DHT), increased significantly the content of 5-HT(2A)R mRNA and SERT mRNA in the dorsal raphe nucleus (DR) and the density of 5-HT(2A)R and SERT binding sites in higher centers of the brain. The lack of effect of 5alpha-DHT, a potent androgen which cannot be converted to estrogen, suggests that the action of testosterone depends upon its conversion to estrogen by aromatase. This may also explain why estrogen, but not testosterone or 5alpha-DHT, increased the density of 5-HT(2A)R binding sites in the caudate-putamen, a brain region where aromatase is scarce. The estrogen induction of SERT mRNA is most prominent in the rostral DR and this together with the correlation between sensitivity of DR serotonin neurons to estrogen and neurotoxic amphetamine derivatives provides a potential topochemical handle with which to investigate testosterone/estrogen regulation of SERT gene expression. These findings are discussed in relation to the possible role of interactions between sex steroids and serotonin mechanisms in mood disorders, schizophrenia and Alzheimer's disease.

Affect↗
PubMed1999

Serotonin transporter (SERT) mRNA and binding site densities in male rat brain affected by sex steroids.

Estrogen increases serotonin transporter (SERT) mRNA and binding sites in female rat brain. In order to determine whether changes in SERT are gender- and steroid-specific we have now carried out studies on adult male Wistar rats which were either intact or castrated (under halothane anesthesia) and injected with arachis oil, estradiol benzoate (EB), testosterone propionate (TP) or the non-aromatizable androgen, 5alpha-dihydrotestosterone (5alpha-DHT). The number of SERT mRNA-expressing cells in the dorsal raphe (DR) nucleus was decreased by castration and increased by treatment (for approximately 32 h) with EB or TP, but not 5alpha-DHT. Sex steroids had no effect on the number of SERT mRNA-expressing cells in the median raphe nucleus. The density of SERT sites, assessed by autoradiography of [3H]paroxetine binding, was significantly reduced in arcuate nucleus and median raphe after castration, and increased in arcuate, basolateral amygdala and ventromedial hypothalamic nucleus by treatment with EB or TP, but not 5alpha-DHT. Estradiol, but not testosterone or 5alpha-DHT reduced the density of SERT sites in midbrain central grey. These data show that testosterone as well as estrogen affects SERT expression in male brain, and that the action of testosterone probably depends upon its enzymatic conversion, by aromatase, to estradiol. Our findings may have implications for sex steroid control of mood and behavior, and the action of neurotoxic derivatives of amphetamine, such as 3, 4-methylenedioxymethamphetamine, in the human.

Animals↗
PubMed1999

Interferon-alpha does not improve outcome at one year in patients with diffuse cutaneous scleroderma: results of a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To determine whether interferon-alpha (IFNalpha) reduces the severity of skin involvement in early (<3 years) diffuse scleroderma. METHODS: In a randomized, placebo-controlled, double-blind trial, 35 patients with early scleroderma received subcutaneous injections of either IFNalpha (13.5 x 10(6) units per week in divided doses) or indistinguishable placebo. Outcomes assessed were the modified Rodnan skin score, as determined by a single observer at baseline, 6 months, and 12 months, as well as data on renal, cardiac, and lung function. Pre- and posttreatment skin biopsy samples were analyzed and blood was obtained for assessment of procollagen peptide levels. RESULTS: There were 11 withdrawals from the IFNalpha group and 3 from the placebo group due to either toxicity, lack of efficacy, or death. In the intent-to-treat analysis, there was a greater improvement in the skin score in the placebo group between 0 and 12 months (mean change IFNalpha -4.7 versus placebo -7.5; P = 0.36). There was also a greater deterioration in lung function in patients receiving active therapy, as assessed by either the forced vital capacity (mean change IFNalpha -8.2 versus placebo +1.3; P = 0.01) or the diffusing capacity for carbon monoxide (mean change IFNalpha -9.3 versus placebo +4.7; P = 0.002). Skin biopsy showed no significant decrease in collagen synthesis in the IFNalpha group, and no significant differences in the levels of procollagen peptides were seen between the 2 groups. CONCLUSION: This study suggests that IFNalpha is of no value in the treatment of scleroderma, and that it may in fact be deleterious.

Adolescent↗
PubMed1999

Comparison of dorzolamide and pilocarpine as adjunctive therapy in patients with open-angle glaucoma and ocular hypertension.

Many patients with glaucoma or ocular hypertension initially receive beta-blocker monotherapy to control intraocular pressure (IOP), but some of these patients will require an additional IOP-lowering agent within 1 year. This active-controlled, double-masked, randomized, multicenter, 12-week study compared the effectiveness and tolerability of dorzolamide hydrochloride ophthalmic solution 2% TID with those of pilocarpine hydrochloride 2% QID as adjunctive therapy to timolol maleate ophthalmic gel-forming solution (TG) 0.5% QD as measured by changes in IOP and occurrence of adverse events. One hundred ninety-four patients with open-angle glaucoma or ocular hypertension participated in this study. Their mean age was approximately 63 years. Slightly more than one half were white, and approximately one third were black. After a 3-week run-in period during which all patients received TG 0.5% QD, patients with an IOP of > or = 22 mm Hg at the morning trough measurement were randomly assigned to receive additional double-masked therapy with either dorzolamide or pilocarpine. The primary outcome measure was the mean change in IOP at the morning trough measurement from baseline to week 12. The secondary outcome measure was the mean change in IOP at the morning peak measurement from baseline to week 12. There was no significant difference in IOP-lowering effect between the 2 drugs at either morning trough or morning peak. The mean change in IOP at morning trough was -3.17 mm Hg (-12%) in patients receiving dorzolamide; it was -3.45 mm Hg (-13%) in patients receiving pilocarpine. The mean change in IOP at morning peak was -2.25 mm Hg (-10%) for patients who received dorzolamide and -2.51 mm Hg (-11%) for those who received pilocarpine. In the pilocarpine group, 62 (63%) patients experienced > or =1 adverse event compared with 35 (36%) patients in the dorzolamide group (P < 0.001). Twenty-one (21%) patients in the pilocarpine group discontinued treatment because of an adverse event compared with 2 (2%) patients in the dorzolamide group (P < 0.001). These results demonstrate that dorzolamide and pilocarpine were equally effective as adjunctive therapy in lowering IOP but that dorzolamide was better tolerated.

Adjuvants, Pharmaceutic↗
PubMed1999

Structure-function studies of omega-atracotoxin, a potent antagonist of insect voltage-gated calcium channels.

The omega-atracotoxins are a family of 36 to 37-residue peptide neurotoxins that block insect but not mammalian voltage-gated calcium channels. The high phylogenetic specificity of these toxins recommends them as lead compounds for targeting insects that have developed resistance to chemical pesticides. We have begun to examine structure-function relationships in the omega-atracotoxins in order to explore the molecular basis of their activity and phylogenetic specificity. By probing the venom of the Blue Mountains funnel-web spider, Hadronyche versuta, for insecticidal toxins with masses close to that of omega-atracotoxin-Hv1a (omega-ACTX-Hv1a), we have isolated and sequenced five additional omega-atracotoxins. Five of the six omega-atracotoxins isolated from the venom of H. versuta (omega-ACTX-Hv1a to -Hv1e) differ from one another by only 1-3 residues and have similar insecticidal potencies. In contrast, omega-ACTX-Hv1f differs from the other toxins by up to 10 residues and it has markedly reduced insecticidal potency, thus providing information on key functional residues. The new atracotoxin sequences have revealed that the three N-terminal residues are highly conserved. Despite the fact that these residues are structurally disordered in solution we show here, by a series of N-terminal truncations, that they contribute significantly to insecticidal potency. However, loss of activity does not correlate with deletion of highly conserved residues, which leads us to propose that the disposition of the N-terminal charge, rather than the chemical properties of the N-terminal residues themselves, may be critical for the activity of omega-atracotoxin on insect calcium channels.

Amino Acid Sequence↗
PubMed1999

Long-term stroma-dependent cultures are a consistent source of immunostimulatory dendritic cells.

A long-term culture (LTC) system has been established that supports the continuous production of dendritic cells (DC) from haemopoietic cells present in the culture. The production of cells depends on the presence of an intact stromal cell layer containing a mixture of fibroblasts and endothelial cells. Cells are shed from foci of dividing cells in contact with the stromal cell matrix. They resemble DC in terms of morphology and cell surface marker expression. The LTC can be derived from different lymphoid tissues, but most success has been achieved with murine spleen. Different LTC vary in capacity to produce immunostimulatory DC. Some LTC produce DC that are very effective APC and can stimulate both mixed lymphocyte and antigen-specific T cell responses. The DC produced in others are weak APC. Different LTC appear to produce DC reflecting different stages of maturation or development, reflected by different phenotypic and functional characteristics. The production of cells within LTC occurs independently of added cytokines and is dependent on maintenance of the stromal cell layer and the presence of a subset of smaller progenitor cells. Long-term cultures remain a valuable source of cells for study of DC development and function.

Animals↗
PubMed1999

The outcome of five years' implementation of maternal serum screening for Down's syndrome comparing actual age risks and mode of delivery.

In this paper 13 613 triple test results from the period 1992- 1997 were analysed. The probability of receiving a high risk result for Down's syndrome from a serum screen, related to the patient's age, was calculated. The modes of delivery of the patients receiving a high risk result were also compared with the rest of the population. The probability of receiving a high risk result increased from 1.2% at 25 years of age to 43.9% at 40 years of age. There was a decrease in the likelihood of having operative intervention at delivery amongst the high risk group but this did not reach statistical significance. This highlights the need for accurate information in risk and probability when counselling a patient undergoing serum screening. Patient's anxiety relating to mode of delivery may also be alleviated by knowing they have no greater risk of operative delivery.

Journal Article↗
PubMed1999

Immunotherapeutic potential of dendritic cells generated in long-term stroma-dependent cultures.

Long term cultures (LTC) producing dendritic cells (DC) have been established from spleen. A well developed stromal cell layer supported production of DC in numbers suitable for experimentation. Cells had obvious membrane pseudopodia and could be collected from culture every 2-3 days. Large cells produced in LTC stained with fluorescently labelled monoclonal antibodies specific for DC such as 33D1, and M1/70 which is specific for DC and myeloid cells. These staining patterns confirmed the presence of DC within the LTC population. LTC-DC were tested and shown capable of migration in vivo in B10.A(2R) mice following footpad inoculation. Most cells entered the spleen and a small number entered popliteal lymph node. LTC-DC have migratory capacity comparable with control spleen lymphocytes. LTC-DC were tested for capacity to induce an anti-tumour immune response after exposing cells to tumour cell membranes. LTC-DC pulsed with BL/VL3 tumour antigens were able to induce a BL/VL3-specific primary cytotoxic T lymphocyte (CTL) response detectable in popliteal lymph nodes and spleen of C57BL/6J mice within 6 days of priming. BL/VL3 tumour cells grew in sublethally irradiated C57BL/6J mice giving 100% mortality. Adoptive transfer of spleen cells from mice given BL/VL3 antigen-pulsed LTC-DC, two weeks previously, significantly slowed the growth of BL/VL3 tumour cells in mice. DC produced in LTC can function as antigen presenting cells (APC) when adoptively transferred into animals. Their capacity to migrate effectively, to induce a CTL response and to reduce tumour load suggests that DC grown using this in vitro system may have valuable clinical potential in humans.

Adoptive Transfer↗
PubMed1999

Probucol improves symptoms and reduces lipoprotein oxidation susceptibility in patients with Raynaud's phenomenon.

OBJECTIVE: Reactive oxygen species have been implicated in the pathogenesis of inflammatory and vascular disease. We have undertaken a controlled trial to evaluate probucol, a synthetic antioxidant, as a potential therapy for Raynaud's phenomenon. METHODS: The study cohort included patients with systemic sclerosis (SSc; n = 20), primary Raynaud's phenomenon (n = 15) or 'autoimmune Raynaud's' (n = 5). Patients were allocated to receive either probucol (500 mg daily) or nifedipine (20 mg daily) for 12 weeks. Clinical and biochemical variables at baseline were compared with those at completion of treatment. Evaluation included assessment of Raynaud's attack frequency and severity by visual analogue scale, measurement of low-density lipoprotein (LDL) oxidation lag time, and plasma concentrations of cholesterol, triglyceride, vitamin E and vitamin C. RESULTS: There was a significant reduction of both the frequency and severity of Raynaud's attacks in the patients who received probucol, but not in the control group. LDL oxidation lag time, reflecting in vitro susceptibility to oxidation, was also increased by probucol therapy and serum cholesterol levels were significantly reduced. Similar changes were observed in both SSc- and non-SSc-associated Raynaud's cases. CONCLUSION: These data suggest that probucol may be useful for the symptomatic treatment of Raynaud's phenomenon and also reduces LDL oxidation susceptibility. Since oxidized lipoproteins may mediate vascular damage in SSc, the use of probucol could have additional disease-modifying benefits. Based upon the results of this pilot study, further evaluation of this novel form of therapy is warranted.

Anticholesteremic Agents↗
PubMed1999

A randomized study of dorzolamide in the prevention of elevated intraocular pressure after anterior segment laser surgery. Dorzolamide Laser Study Group.

PURPOSE: To evaluate the efficacy of 2% dorzolamide hydrochloride opthalmic solution in preventing spikes in intraocular pressure (IOP) after anterior segment laser surgery. METHODS: This 24-hour, placebo-controlled, randomized, double-masked, multicenter evaluation was conducted to determine the efficacy of dorzolamide hydrochloride 2% in controlling IOP after neodimium:yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy, argon laser trabeculoplasty, or laser iridotomy. The 122 patients enrolled were assigned in randomized fashion to receive dorzolamide or placebo 1 hour before and immediately after the procedure; IOP was measured 1, 2, 3, 4, and 24 hours after the procedure. RESULTS: Of 61 patients receiving dorzolamide, only one (1.7%) had a spike in IOP of 10 mmHg or more, compared with 9 (14.8%) of the 61 patients receiving placebo. Mean IOP among patients receiving dorzolamide was significantly reduced both from baseline and compared with that among patients receiving placebo from 1 to 4 hours after administration. Only 5 (8%) of the 61 patients receiving dorzolamide experienced at least one adverse event, compared with 15 (25%) of the 61 patients receiving placebo. CONCLUSION: Dorzolamide was effective in preventing spikes in IOP after anterior segment laser surgery. Dorzolamide was generally well tolerated after short-term use.

Anterior Eye Segment↗