Search PubMed⌕ Search

Biomedical subjects

T Brown

Publications and source records attributed to T Brown.

At least 91 records · Page 5Linked to original sources
PubMed2000

AIDS, risk and social governance.

This paper considers the discursive properties of public health literature produced around AIDS in the 1980s and early 1990s. Attention is focused upon the role of health promotion in the UK government's response to the epidemic and on the language used in the educational campaigns conducted by the Health Education Council and its replacement the Health Education Authority. Using an analytical approach influenced by the work of Michel Foucault, the paper argues that the knowledges of AIDS produced by these various public health institutions constructed discursive boundaries between the idea of 'normal' and 'abnormal' behavioural practices. The notion of risk, produced as it is from epidemiological knowledge, is a central mechanism in this process. It is through the production, articulation and normalisation of 'at risk' groups that society is fragmented and hence subject to the governance strategies of late-modern liberal economies.

Acquired Immunodeficiency Syndrome↗
PubMed2000

The young dancer.

The injuries that are prevalent in and unique to dancers have their origins inextricably linked to faulty technique or poor biomechanics, combined with other risk factors. It is this combination of factors that must be addressed when considering diagnosis, treatment, and rehabilitation. For the dancer to return to full activity with minimal risk of recurrent injury, neuromuscular re-education is mandatory. This process best entails using a team approach, accessing the resources of healthcare professionals and those who train the dancer on a daily basis. In some cases, parents also may need to be involved. Communication, interaction, and mutual understanding among these groups will assist the dancer in regaining and maintaining health.

Adolescent↗
PubMed2000

London's burning: recovering other geographies of health.

In the opening to this paper we concern ourselves with the concept of health as it is currently understood in the now reformulated 'geography of health'. We focus on countering the assumption that the desire for health is the main drive behind individual patterns of consumption. To this end, we turn to a more culturally informed analysis which identifies the importance of understanding the complex relations between the body, identity, consumption and risk. To illustrate our ideas and arguments, we draw on current anti-smoking debates, particularly those relating to passive smoking, and what we see as evidence of alternatives to such health-related or 'healthist' rhetoric: the rise of cigar smoking and cigar bars in London, England.

Consumer Behavior↗
PubMed2000

Loss of neurofibromatosis 1 (NF1) gene expression in NF1-associated pilocytic astrocytomas.

The critical role of the neurofibromatosis 1 (NF1) gene as a tumour suppressor has been clearly demonstrated for malignancies arising in NF1 patients. However, little is known about the more common benign tumours, such as the pilocytic astrocytoma. Most NF1-associated astrocytomas are benign and clinically non-progressive, though aggressive tumours are occasionally encountered. In this study, eight pilocytic astrocytomas from six individuals affected with NF1 were analysed for NF1 expression. All eight tumours demonstrated loss of neurofibromin expression by immunohistochemistry, which was confirmed in one case using Western blot analysis. Microsatellite analysis showed loss of a single NF1 allele (LOH) in two of four NF1-associated tumours. These results demonstrate that, in contrast to sporadic astrocytomas, loss of NF1 expression is an important primary genetic event in the pathogenesis of NF1-associated pilocytic astrocytomas.

Adolescent↗
PubMed2000

Dermatologist and electrologist perspectives on laser procedures by nonphysicians.

BACKGROUND: As hair removal technology continues to evolve and new equipment comes to market, conflicts may develop between dermatologists and electrologists regarding the professional control and use of these devices. METHODS: A total of 1004 Fellows of the American Academy of Dermatology and 719 electrologists from the southern United States were anonymously surveyed about clinical laser procedures (CLPs). RESULTS: Compared to electrologists, dermatologists were more likely to support clinical laser regulations that placed licensed physicians in control (P =.001) and preferred that a delegating physician be physically present on the premises when CLPs were performed (P =.001). If a laser device was invented for permanent hair removal that was identical to traditional needle/probe electrolysis in every respect except energy type ("laser fiberoptic probe," LFP), electrologists were more likely than dermatologists to support independent use of this device by electrologists (P =.001). A greater percentage of electrologists from Texas, a state without electrolysis licensing, were more likely to support the unlicensed use of the LFP and CLPs than electrologists from states requiring electrolysis licensing. CONCLUSIONS: These data are consistent with previously published literature and permit a greater understanding of the multiple attitudinal, regulatory, and ethical issues involved when considering delegated and independent CLPs by electrologists.

Allied Health Personnel↗
PubMed2000

Assessment of long-term outcomes of community-acquired hepatitis C infection in a cohort with sera stored from 1971 to 1975.

The aim of this study was to examine the long-term effects of hepatitis C virus (HCV) infection on a cohort of patients admitted with acute viral hepatitis from 1971 through 1975. The availability of stored sera from this time enabled testing to identify those who were anti-HCV-positive on admission. Sixteen percent (n = 238) of the cohort tested anti-HCV-positive. The unexposed group was selected from those who were anti-HCV-negative. Systematic approaches were used to locate the cohort and health outcomes assessed by a study-specific questionnaire and clinical, serological, virological, and biochemical assessment. Complete follow-up was achieved on 98 anti-HCV-positive individuals and 201 negatives. Injecting drug use (IDU) was the presumed route of infection. At a mean of 25 years' follow-up, 54% of the anti-HCV-positive group had evidence of chronic HCV infection (both anti-HCV- and HCV-RNA-positive); the remainder were HCV-RNA-negative. Sixty-nine percent of those chronically infected had elevated serum alanine transaminase (ALT) levels, but only 8% had progressed to overt cirrhosis, and no cases of hepatocellular carcinoma (HCC) were identified. In summary, anti-HCV-positive subjects were 8 times more likely to have died from suicide or drug overdose than from HCV-related disease. Anti-HCV-positive study subjects were at increased risk of liver-related pathology after 25 years' follow-up, but few had progressed to overt cirrhotic liver disease. Excess mortality in this group was not the result of liver disease. This suggests that the natural history of community-acquired HCV may be more benign than previously thought.

Adult↗
PubMed2000

Effect of operative volume on morbidity, mortality, and hospital use after esophagectomy for cancer.

OBJECTIVE: We sought to evaluate the effect of operative volume, hospital size, and cancer specialization on morbidity, mortality, and hospital use after esophagectomy for cancer. METHODS: Data derived from the Health Care Utilization Project was used to evaluate all Medicare-reimbursed esophagectomies for treatment of cancer from 1994 to 1996 in 13 national cancer institutions and 88 community hospitals. The complications of care, length of stay, hospital charges, and mortality were assessed according to hospital size (>/=600 beds vs <600 beds), cancer specialization (national cancer institution vs community hospital), and operative volume (esophageal [>/=5 Medicare esophagectomies per year vs <5 Medicare esophagectomies per year] and nonesophageal operations [>/=3333 cases per year vs <3333 cases per year]). RESULTS: Mortality was lower in national cancer institution hospitals (4.2% [confidence interval, 2.0%-6.4%] vs 13.3% [confidence interval, 4.2%-26.2%], P =. 05) and in hospitals performing a large number of esophagectomies (3. 0% [confidence interval, 0.09%-5.1%] vs 12.2% [confidence interval, 4.5%-19.8%], P <.05). Multivariate analysis revealed that the independent risk factor for operative mortality was the volume of esophagectomies performed (odds ratio, 3.97; P =.03) and not the number of nonesophageal operations, hospital size, or cancer specialization. Hospitals performing a large number of esophagectomies also showed a tendency toward decreased complications (55% vs 68%, P =.06), decreased length of stay (14.7 days vs 17.7 days, P =.006), and decreased charges ($39,867 vs $62, 094, P <.005). CONCLUSIONS: These results demonstrate improved outcomes and decreased hospital use in hospitals that perform a large number of esophagectomies and support the concept of tertiary referral centers for such complex oncologic procedures as esophagectomies.

Aged↗
PubMed2000

Protease inhibitor therapy in HIV-infected children.

We reviewed the short-term response to and safety of protease inhibitor (PI) therapy in HIV-infected children by performing a retrospective chart review of open-label PI containing combination therapy at two urban pediatric HIV centers. Seventy HIV-infected children received 101 PI containing antiretroviral therapy (ART) combinations. Main outcome measures were follow-up CD4 counts, viral loads, and patient or caregiver reported compliance. During follow-up, treatment with PI ART was associated with a mean maximal increase in CD4+ lymphocyte count of 454 x 10(6)/L and a mean maximal decrease in viral load of 1.76 log units. Of the 32 patients who achieved undetectable viral loads, 28 (87.5%) remained undetectable through a mean follow-up of 8.9 months. Patients who reported good compliance achieved a higher rate of response (92.6%) than those who reported poor compliance (61.5%). Of 14 changes made to a second PI because of treatment failure, 11 (78.6%) resulted in a positive response to the second regimen. Nineteen of 101 courses of PI therapy resulted in significant side effects, including renal complications in 8 of 21 patients treated with indinavir. PI ART was associated with substantial short-term improvement in immunological and virological parameters in this heavily pretreated cohort, with 40% of patients maintaining an undetectable viral load after 9 months of therapy. Patients who failed one PI regimen usually responded to a second regimen. There was a significant rate of side effects from PI treatment.

Adolescent↗
PubMed2000

Recovery of spermatogenesis and successful conception after bone marrow transplant for acute leukaemia: case report.

A case is presented of a young adult male diagnosed with acute myeloid leukaemia who was treated with busulphan and cyclophosphamide, but not total body irradiation, with subsequent bone marrow transplantation. After surviving for 5 years, he and his wife experienced a period of infertility. Interestingly, the problem was found to be with the female partner and the man's sperm evaluation seemed normal. A successful pregnancy ensued following the surgical removal of a large endometrioma and treating a luteal phase deficiency. Though this may be the fifth case of proven parentage in cases of bone marrow conditioning and bone marrow transplantation in a male for control of leukaemia, we believe it is the first documented case showing a normal semen analysis despite treatment. Further studies are needed to see if chemical conditioning with busulphan and cyclophosphamide preserve the chances of sperm production better than total body irradiation.

Adult↗
PubMed2000

Standardization of immunoglobulin M capture enzyme-linked immunosorbent assays for routine diagnosis of arboviral infections.

Immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) is a rapid and versatile diagnostic method that readily permits the combination of multiple assays. Test consolidation is especially important for arthropod-borne viruses (arboviruses) which belong to at least three virus families: the Togaviridae, Flaviviridae, and Bunyaviridae. Using prototype viruses from each of these families and a panel of well-characterized human sera, we have evaluated and standardized a combined MAC-ELISA capable of identifying virus infections caused by members of each virus family. Furthermore, by grouping antigens geographically and utilizing known serological cross-reactivities, we have reduced the number of antigens necessary for testing, while maintaining adequate detection sensitivity. We have determined that a 1:400 serum dilution is most appropriate for screening antiviral antibody, using a positive-to-negative ratio of >/=2.0 as a positive cutoff value. With a blind-coded human serum panel, this combined MAC-ELISA was shown to have test sensitivity and specificity that correlated well with those of other serological techniques.

Antibodies, Viral↗
PubMed2000

BNIP3 and genetic control of necrosis-like cell death through the mitochondrial permeability transition pore.

Many apoptotic signaling pathways are directed to mitochondria, where they initiate the release of apoptogenic proteins and open the proposed mitochondrial permeability transition (PT) pore that ultimately results in the activation of the caspase proteases responsible for cell disassembly. BNIP3 (formerly NIP3) is a member of the Bcl-2 family that is expressed in mitochondria and induces apoptosis without a functional BH3 domain. We report that endogenous BNIP3 is loosely associated with mitochondrial membrane in normal tissue but fully integrates into the mitochondrial outer membrane with the N terminus in the cytoplasm and the C terminus in the membrane during induction of cell death. Surprisingly, BNIP3-mediated cell death is independent of Apaf-1, caspase activation, cytochrome c release, and nuclear translocation of apoptosis-inducing factor. However, cells transfected with BNIP3 exhibit early plasma membrane permeability, mitochondrial damage, extensive cytoplasmic vacuolation, and mitochondrial autophagy, yielding a morphotype that is typical of necrosis. These changes were accompanied by rapid and profound mitochondrial dysfunction characterized by opening of the mitochondrial PT pore, proton electrochemical gradient (Deltapsim) suppression, and increased reactive oxygen species production. The PT pore inhibitors cyclosporin A and bongkrekic acid blocked mitochondrial dysregulation and cell death. We propose that BNIP3 is a gene that mediates a necrosis-like cell death through PT pore opening and mitochondrial dysfunction.

Apoptosis Inducing Factor↗
PubMed2000

Has the history of Canadian medicine come of age? A personal view.

This short "think piece" interrogates the present state of medical history in Canada. What, I ask, are the past accomplishments and future prospects of this new genre of historical writing in Canada? Has Canadian medical history come of age? And what do we mean by asking this question? My answer is that while there is much to celebrate in the sterling individual works in the field in the past 20 years, the field more generally has yet to confront more difficult questions of identity, theory and methodology that, in my view, any young subfield needs to tackle to survive in the presently overcrowded academic marketplace of approaches and ideas.

Canada↗
PubMed2000

5-hydroxytryptamine- and U46619-mediated vasoconstriction in bovine pulmonary conventional and supernumerary arteries: effect of endogenous nitric oxide.

We compared 5-hydroxytryptamine (5-HT)- and U46619-mediated contractions in bovine pulmonary conventional arteries (CA) and supernumerary arteries (SA). The effects of the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (100 microM) and the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4, 3-a]quinoxalin-1-one (ODQ) (10 microM) on the responses of CA and SA to 5-HT and U46619 were also examined. In addition, the effects of the 5-HT(2B) receptor antagonist SB 200646 (1 nM-1 microM) on the responses to 5-HT in SA and CA were studied. Tissue cGMP levels were measured in the absence and presence of L-NAME, ODQ, 5-HT and U46619. 5-HT was approximately 30 times more potent in SA ¿-log[EC(50) (M)] (pEC(50)) 6.32+/-0.13¿ than in CA (5.05+/-0.14). U46619 displayed a similar potency in both CA (pEC(50) 7.80+/-0.07) and SA (7.75+/-0. 12). L-NAME did not significantly alter the resting tone of CA or SA. In contrast, ODQ produced a transient increase in the tone of both CA and SA. Neither L-NAME nor ODQ altered the responses to 5-HT or U46619 in CA. In addition, neither L-NAME nor ODQ altered the responses to U46619 in SA, but both L-NAME and ODQ increased the magnitude of the response to 5-HT in SA without changing the sensitivity. Inhibition of the 5-HT(2B) receptor with SB 200646 did not alter the response to 5-HT in SA or CA. Basal levels of cGMP (pmol/mg of protein) were similar in CA (1.16+/-0.33) and SA (0. 8+/-0.51), and were not significantly changed in the presence of 5-HT or U46619. L-NAME and ODQ reduced the basal levels of cGMP in both SA and CA. The results suggest that endogenous NO selectively attenuates the vasoconstrictor response to 5-HT in SA, but not in CA. These results also suggest that the NO/cGMP pathway may have a role in maintaining low vascular tone, but that other mechanisms are able to compensate for the absence of this pathway.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2000

A clinical approach to the management of the patient with coronary (Co) and/or carotid (Ca) artery disease who presents with leg ischaemia (Lis).

The purpose of this document is to provide the clinician with easy-to-use guidelines when faced with a patient with severe ischaemia in the limbs requiring interventional treatment; the CoCaLis document does not focus on the management of the lower limb ischaemia, but rather on the best possible approach to the associated coronary and/or carotid artery disease. The first part of the text deals with the epidemiological aspects of this condition followed by a description of, and proposals for, the management of risk factors. The next part deals with the approach to the coronary circulation and the carotid territory. In each part attention is mainly given to the practical aspects in terms of both diagnosis and treatment; for each of these steps the costs involved are considered and attention given to balancing the clinical decisions against the costs. The recommendations given are 'evidence based' when such evidence exists and, if not, the proposals are based on the consensus of the members of the group. In many instances it was apparent that the necessary information is not available in the literature. The authors hope that the CoCaLis document may not only improve the management of the vascular patient but also stimulate further research in this difficult clinical condition which carries a significantly increased risk for the patient.

Angioplasty, Balloon, Coronary↗
PubMed2000

Optimizing the use of rituximab for treatment of B-cell non-Hodgkin's lymphoma: a benefit-risk update.

Rituximab (Rituxan; Genentech, Inc, South San Francisco, CA and IDEC Pharmaceutical Corporation, San Diego, CA), the first monoclonal antibody approved in the United States for the treatment of cancer, is indicated for the treatment of patients with relapsed or refractory CD20+ low-grade non-Hodgkin's lymphoma. From November 1997 through May 1999, approximately 36,000 patients have been treated with rituximab. Serious cardiopulmonary infusion reactions culminating in death have been reported to occur in approximately 0.04% to 0.07% of patients. Post-approval tumor lysis syndrome has been reported within 12 to 24 hours after the first antibody infusion and is estimated to occur in 0.04% to 0.05% of patients. The risk of tumor lysis appears to be higher in patients with high numbers of circulating malignant cells. Serious infusion-related adverse drug reactions, most often consisting of cardiopulmonary reactions associated with the rapid lysis of large numbers of circulating malignant cells, have been fatal in approximately 0.5 per 1,000 treated patients. Major risk factors include high numbers of circulating malignant lymphoma cells, pulmonary infiltrates or lymphoma involvement, and prior cardiovascular disease. This report updates the safety experience of rituximab therapy with data from clinical trials and postmarketing safety experience, and examines how this information can be used to optimize therapy.

Antibodies, Monoclonal↗
PubMed2000

Estradiol/progesterone substitution in the luteal phase improves pregnancy rates in stimulated cycles--but only in younger women.

Innumerable studies have attempted to demonstrate that hormonal support of the luteal phase during ovulation induction cycles improves pregnancy rates. None has, however, so far been able to confirm the validity of such treatment conclusively, possibly because most studies only utilized progesterone substitution. Since luteal phase endometrium also requires estradiol support, this study attempted to investigate whether hormone substitution with progesterone and estradiol would be more successful in improving pregnancy rates. Amongst approximately 7500 consecutive ovulation induction cycles were identified prospectively which were characterized by a precipitous drop of luteal phase serum estradiol levels by more than 50% over a 48 hour period within 10 days from hCG administration. Those cycles were prospectively randomized to oral micronized estradiol substitution (Group I) or not (Group II), while both groups received routine progesterone substitution of the luteal phase. Cycles were then evaluated in regards to the occurrence of chemical, ectopic and clinical pregnancies. One hundred sixty-three Group I cycles resulted in 34 pregnancies (20.9%), which compared favorably to 21 pregnancies in 167 Group II patients (12.6%) (x2[1] = 4.06; p < 0.04). The advantage for Group I cycles (29/95 pregnancies, 31%) vs. Group II cycles (16/105, 15%) became even more pronounced when only women up to age 35 years were evaluated. Estradiol substitution maintained a significant advantage until age 38 (x2 [1] = 6.87; p < 0.009). While gravidity did not affect pregnancy success, estradiol substitution in Group I benefited nulliparous (23% pregnancy rate) over multiparous women (12% pregnancy rate) (x2 [2] = 6.86; p< 0.03). This association was, however, age-dependent. A combined estradiol and progesterone substitution of the luteal phase of ovulation induction cycles increases the overall pregnancy rate. Since estradiol substitution was initiated in this study only once a precipitous drop in serum estradiol levels had already taken place, an even larger improvement in pregnancy rates could conceivably be possible if earlier estradiol substitution of the luteal phase is initiated. A further expansion of investigations of similar protocols for routine ovulation induction and in vitro fertilization (IVF) cycles may be indicated, especially in women below age 38 years and in nulliparous females.

Administration, Oral↗
PubMed1999

Country-specific estimates and models of HIV and AIDS: methods and limitations.

OBJECTIVE: This paper presents the methods used to calculate the end of 1997 country-specific estimates of HIV and AIDS produced by the UNAIDS/WHO Working Group on Global HIV/AIDS and STD Surveillance. The objective of this exercise was to improve estimates on HIV/AIDS by using country-specific models of HIV/AIDS epidemics. The paper describes and discusses the processes and obstacles that were encountered in this multi-partner collaboration including national and international experts. METHODS: The 1997 estimates required two basic steps. First, point prevalence estimates for 1994 and 1997 were carried out and the starting year of the epidemic was determined for each country. The procedures used to calculate the estimates of prevalence differed according to the assumed type of the epidemic and the available data. The second step involved using these estimates of prevalence over time and the starting date of the epidemic to determine the epidemic curve that best described the spread of HIV in each particular country. A simple epidemiological program (EPIMODEL) was used for the calculation of estimates on incidence and mortality from this epidemic curve. RESULTS: Regional models that were used in previous estimation exercises were not able to capture the diversity of HIV epidemics between countries and regions. The result of this first country-specific estimation process yielded higher estimates of HIV infection than previously thought likely, with over 30 million people estimated to be living with HIV/AIDS. The application of survival times that are specific to countries and regions also resulted in higher estimates of mortality, which more accurately describe the impact of the epidemics. At the end of 1997, it was estimated that 11.7 million people worldwide had died as a result of HIV/AIDS since the beginning of the epidemic. CONCLUSION: This exercise is an important step in improving understanding of the spread of HIV in different parts of the world. There are, however, shortcomings in the current systems of monitoring the epidemic. Improvements in HIV surveillance systems are needed in many parts of the world. In addition, further research is needed to understand fully the effects of the fertility reduction as a result of HIV, differing sex ratios in HIV infection and other factors influencing the course and measurement of the epidemic.

Acquired Immunodeficiency Syndrome↗