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Biomedical subjects

S Houston

Publications and source records attributed to S Houston.

At least 19 recordsLinked to original sources
PubMed1999

Regional changes in the expression of neurotrophic factors and their receptors following acute traumatic brain injury in the adult rat brain.

We have analyzed the effect of severe traumatic brain injury (TBI) on the levels of mRNA expression of neurotrophic factors (NTFs): brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF) and their respective receptors: trkB, trkA and CNTFRalpha. The expression was examined in the region of the lesion as well as a region remote from the lesion at 12, 24, and 36 h following the injury. Our data suggest that after the brain injury, the expression of NGF and BDNF mRNAs were early, transiently and significantly upregulated while that of CNTF was a slow and less amplified response in both areas of the brain. We also found that trkA mRNA expression was only upregulated significantly in the remote area; trkB mRNA showed no significant change in either area except an upregulation at 12 h in the remote area. CNTFRalpha was downregulated significantly by 24-36 h in the lesion area and by 24 h in the remote area. These changes suggest that TBI regulates the expression of NTFs and their receptors. These alterations in expression may be involved in modulating the neuronal response after brain injury.

Age Factors↗
PubMed1999

Economic implications of an early postoperative enteral feeding protocol.

OBJECTIVE: To study the cost-effectiveness of an early postoperative feeding protocol for patients undergoing bowel resections. DESIGN: A nonrandomized, prospective, clinical trial. Surgeons elected to participate in the treatment arm before the study's outset. SUBJECTS/SETTING: Treatment (n = 66) and control (n = 159) patients were admitted to a nonprofit general teaching hospital in the Texas Medical Center for similar diagnoses and subsequent bowel resections during an 18-month period. INTERVENTION: Treatment patients who met specific inclusion criteria had a jejunal feeding tube placed during surgery. Tube feedings were initiated within 12 hours after surgery. Control patients who met the same inclusion criteria received usual care. OUTCOMES: A successful outcome was defined as a patient developing no postoperative infection. The average cost of a nosocomial infection is presented. Variable direct and total costs (fixed plus variable) are compared between patient groups. STATISTICAL ANALYSIS: Mean cost was adjusted for rate of success in each patient group according to an analytic model. The mean cost difference between groups was analyzed by independent-samples t tests. Nonparametric Mann-Whitney rank sum tests were used to determine the cost significance of a nosocomial infection. RESULTS: The average variable direct cost savings per successful treatment patient was $1,531, which required an additional variable cost of $108.30 for the dietitian's time. The protocol resulted in a total cost savings of $4,450 per success in the treatment group. CONCLUSION: An early postoperative enteral feeding protocol as part of an outcomes management program for patients undergoing bowel resection is cost-effective.

Clinical Protocols↗
PubMed1998

Effect of antiretroviral therapy and viral load on the perceived risk of HIV transmission and the need for safer sexual practices.

BACKGROUND: Dramatic reductions in plasma HIV RNA levels are possible with current antiretroviral regimens; the effect of potent therapies and "undetectable" viral load on the perceived risk of HIV transmission and need for safer practices remains unknown. METHODS: A questionnaire was developed to examine perceptions of HIV transmission risk and need for safer practices with unprotected anal, vaginal, and oral sex and intravenous drug use with needle sharing for HIV-discordant couples in which the HIV-infected partner was receiving no therapy, was receiving reverse transcriptase inhibitor therapy, and protease inhibitor (PI)-based therapy with viral load "undetectable". This was applied anonymously to 147 unselected HIV-infected individuals attending a university-based HIV clinic. RESULTS: Almost all respondents believed that all sexual activities except oral sex were "very risky" and that safer practices were "extremely important" for those not receiving antiretroviral agents. Significantly fewer considered that anal or vaginal sex was "very risky" for those receiving PI therapy (90.9% and 86.0%, respectively), and fewer thought that safer practices for anal or vaginal sex were "very important" for those receiving PI therapy (93.0% and 91.6%, respectively). In total, 20.4% thought the risk of HIV transmission for at least one activity was reduced for those receiving PI therapy, and 19.0% believed that the need for safer practices was reduced by PI therapy. CONCLUSION: A small but significant proportion of HIV-infected people perceive the need for safer practices to be reduced during antiretroviral therapy, particularly those containing PIs. Even if the risk is truly reduced, the importance of safer practices should be conveyed consistently and terms such as "undetectable" to describe HIV RNA responses should be avoided.

Anti-HIV Agents↗
PubMed1998

Combined fluorescent in situ hybridisation and immunolabelling of Bacteroides fragilis.

We have demonstrated that pure cultures of Bacteroides fragilis can be riboprobed with the oligoprobes BAC303 and EUB338, whilst simultaneously immunolabelled with either the mAb QUBF7, or polyclonal antiserum specific for a common antigen of B. fragilis. We were also able to distinguish between pure cultures of B. fragilis and Escherichia coli, by means of combined immunolabelling and riboprobing. The success of the combined technique is critically dependent on the size of the bacterial capsules, bacterial growth phase, antibody diluent and the length of the washing steps. The combined FISH and immunolabelling of bacteria has potential applications in studies of bacteria of medical and veterinary importance, as well as bacteria from other environments, as it yields information about both the identity and antigen expression of individual bacterial cells.

Antibodies, Bacterial↗
PubMed1998

A randomised phase II study of oral pamidronate for the treatment of bone metastases from breast cancer.

47 patients with progressive, painful, predominantly lytic bone metastases from breast cancer were included in a randomised double-blind phase II trial comparing the effects of pamidronate 150 and 300 mg daily. Oral pamidronate produced either sclerosis or stabilisation of lytic metastases for at least 24 weeks in 5 of 24 and 3 of 23 patients at the 300 and 150 mg dose levels, respectively. Evidence of symptomatic improvement was observed in 5 of 22 (23%) and 7 of 22 (32%) patients for symptomatic disease at the respective doses. These improvements were accompanied by a reduction in the rate of bone resorption as shown by suppression (P = < 0.01) of urinary calcium and a non-significant fall in deoxypyridinoline. No obvious differences in efficacy were observed between the two dose levels. Gastrointestinal adverse events, principally comprising nausea and vomiting, were the most commonly reported side-effects leading to discontinuation of trial treatment in 4 of 24 and 2 of 23 patients at 300 and 150 mg dose levels, respectively. The poor tolerability of oral pamidronate coupled with the modest clinical effects reported here suggest that oral pamidronate will not replace the current strategy of regular intravenous infusions of pamidronate for the treatment of osteolytic bone disease.

Administration, Oral↗
PubMed1998

Detection of bone metastases in breast cancer by 18FDG PET: differing metabolic activity in osteoblastic and osteolytic lesions.

PURPOSE: 99mTechnetium methylene diphosphonate (99mTc MDP) bone scintigraphy is currently the method of choice for the detection of bone metastases, but 18F-fluoro-deoxy-D-glucose positron emission tomography (18FDG PET) offers superior spatial resolution and improved sensitivity. We have compared 18FDG PET with 99mTc MDP bone scintigraphy in patients with skeletal metastases from breast cancer and have analyzed the data in subgroups based on radiographic characteristics of lesions. PATIENTS AND METHODS: Twenty-three women with breast cancer and confirmed bone metastases were studied with both 99mTC MDP bone scintigraphy and 18FDG PET, and the number of lesions detected and the quantitation of uptake (standardized uptake values [SUVs]) of 18FDG in osteolytic and osteoblastic metastases were compared. Survival was compared for both lytic and blastic bone metastases and for patients with high and low accumulation of 18FDG. RESULTS: 18FDG PET detected more lesions than 99mTc MDP scintigraphy (mean, 14.1 and 7.8 lesions, respectively; P < .01). However, 18FDG detected fewer bone metastases compared with 99mTc MDP scintigraphy in a subgroup of patients with osteoblastic disease (P < .05). Higher SUVs were observed for osteolytic than osteoblastic disease (mean, 6.77 and 0.95, respectively; P < .01). Survival was lower in patients with osteolytic disease compared with the remainder (P=.01). A difference in survival was not found for those patients with high SUVs (> 3.6; P=.4). CONCLUSION: 18FDG PET is superior to bone scintigraphy in the detection of osteolytic breast cancer metastases, which led to a poorer prognosis. In contrast, osteoblastic metastases show lower metabolic activity and are frequently undetectable by PET. The biologic explanation for this observation remains to be elucidated.

Adult↗
PubMed1998

Factors associated with HIV testing among Canadians: results of a population-based survey.

The purpose of this study was to examine the HIV-testing behaviour of Canadians aged 15 years and older. Questions on HIV testing were asked as part of a Canada-wide random digit dialling telephone survey conducted in December 1995 to January 1996 on health practices and attitudes toward health care in Canada (n=3123). Including blood donation and insurance testing, 40.4% of men and 30.4% of women had been tested for HIV. Excluding blood donation and life-insurance testing (voluntary testing), 17.8% of men and 15.6% of women had been tested. In multivariate analyses, factors independently associated with voluntary testing among men were: having had sex with a man (OR=16.8), injection drug use (OR=5.8), having had a partner at high risk (OR=2.5), having received blood or clotting factor (OR=2.3), being younger than 45 years of age (OR=1.8), living in a city of over one million (OR=1.7), and making less than $30,000 a year (OR=1.6). For women, factors independently associated with voluntary testing were having received blood or clotting factor (OR=3.9), having had a high-risk partner (OR= 3.5), being younger than 45 years of age (OR=2.4), having had sex with a man (OR=2.3), and being unattached (OR=2.0). Results indicated that those at risk are more likely to be tested. It is of concern, however, that many of those reporting risk factors have not been tested. A better understanding of HIV testing behaviour is needed to improve the planning and evaluation of prevention and counselling services.

Adolescent↗
PubMed1998

Technetium-99m-labeled HL91 to identify tumor hypoxia: correlation with fluorine-18-FDG.

UNLABELLED: Technetium-99m HL91 is a potential agent for imaging hypoxic tissue in vivo. A pilot evaluation using a prototype formulation assessed efficacy in tumor imaging and compared results with 18F-fluorodeoxyglucose (FDG) PET. METHODS: Ten patients with malignant tumors were included. Tumors included carcinoma of the bronchus (n = 3), carcinoma of the thyroid (n = 2), lymphoma (n = 2), soft tissue sarcoma (n = 1), carcinoid (n = 1) and carcinoma of the breast (n = 1). Whole-body planar scans and localized SPECT scans were performed at 1 and 4 hr postinjection of 600 MBq 99mTc HL91. Half-body and localized emission/transmission 18F-FDG PET scans were performed 60 min postinjection 370 MBq 18F-FDG in eight patients. Lesion-to-normal tissue background ratios were measured for all 99mTc HL91 and 18F-FDG PET scans and percentage uptake and standardized uptake values measured for 99mTc HL91 and 18F-FDG PET, respectively. RESULTS: Technetium-99m HL91 showed visible uptake into the tumor area in all seven studies where the tumor was clearly identified by 18F-FDG PET; 99mTc HL91 uptake was not detected in one study (carcinoid) in which 18F-FDG was weakly positive. Two further tumors, in which PET correlation was not available, showed accumulation of 99mTc HL91. In two 99mTc HL91 studies, abnormality was apparent only on SPECT images. Lesion-to-normal tissue background ratios for 99mTc HL91 ranged from 1.22/2.53 at 1 hr and 1.33/2.89 at 4 hr on planar images and 1.23/5.2 and 1.67/14.6 on SPECT images, respectively. CONCLUSION: In this study, the use of 99mTc HL91 resulted in uptake in the majority of malignant tumors identified by 18F-FDG-PET. Technetium-99m HL91 exhibits good imaging characteristics, with imaging at 4 hr providing good lesion-to-normal tissue background ratios, that are further enhanced by SPECT.

Aged↗
PubMed1997

Tuberculosis Risk and Prevention in Travelers-What about BCG?

Tuberculosis (TB) is one of the most important health problems in many tropical and developing countries, particularly since the advent of the human immuno- deficiency virus (HIV) epidemic. The level of TB transmission is much greater in these countries than in most of western Europe or North America. For example, the annual risk of infection with Mycobacterium tuberculosis is estimated to be 300 times higher in some subSaharan African countries1 than in the Netherlands.2 Travel guidelines and advice vary widely in the emphasis placed on TB and on specific recommendations for prevention. American sources generally advise that use of the bacille Calmette-Guérin (BCG) vaccine in travelers be limited to exceptional circumstances3 while some European authorities advocate broader use.4-6 This article reviews the risk of TB in travelers and possible approaches to its prevention, including the use of BCG vaccination.

Journal Article↗
PubMed1997

A dose-controlled study of 153Sm-ethylenediaminetetramethylenephosphonate (EDTMP) in the treatment of patients with painful bone metastases.

One hundred and fourteen patients with painful bone metastases participated in this randomised, dose-controlled study of the efficacy and safety of 153Sm-ethylenediaminetetramethylenephosphonate (EDTMP), a systemically administered radiopharmaceutical. Fifty-five patients received single doses of 0.5 mCi/kg and 59 patients received single doses of 1.0 mCi/kg. Treatment with 153-Sm-EDTMP produced improvement from baseline in all patient-rated efficacy assessments, including degree of pain, level of daytime discomfort, quality of sleep and pain relief. During the first 4 weeks after dose administration, when the patients evaluated efficacy daily, there were statistically significant changes from baseline with the 1.0 mCi/kg dose but not with the 0.5 mCi/kg dose. The difference between doses in visual analogue pain scores was statistically significant at week 4 (P = 0.0476). Among subsets of patients examined, female patients with breast cancer receiving 1.0 mCi/kg had the most noticeable improvement. The physicians judged that approximately half of the patients in each dose group were experiencing some degree of pain relief by week 2. This value increased to 55% for the 0.5 mCi/kg group and 70% for the 1.0 mCi/kg group at week 4. More patients in the higher dose group (54%) than in the lower dose group (44%) completed the 16-week study. A predictable level of dose-related marrow suppression was the only toxicity associated with 153Sm-EDTMP treatment. Values for platelets and WBCs reached nadirs at 3 or 4 weeks with both doses and recovered by 8 weeks. Even at their lowest point, the values were generally higher than those associated with infectious or haemorrhagic complications. Myelotoxicity was no greater in female patients than in male patients. Long-term follow-up revealed longer survival among breast cancer patients who had received the higher dose than among those who had received the lower dose. The results suggest that the 1.0 mCi/kg dose of 153Sm-EDTMP is safe and effective for the treatment of painful bone metastases.

Adult↗
PubMed1997

Environmental health conditions in remote and rural aboriginal communities in western Australia.

During 1994-1995 environmental health conditions of about 13,760 persons in 155 remote and rural Aboriginal communities in 20 local shires in Western Australia (WA) were surveyed. A semiquantitative questionnaire sought data about the communities and their services, including water supplies, power, sanitation and disposal of solid and liquid waste; a separate section dealt with conditions of individual dwellings. Data were recorded by experienced local workers. Thirty-five communities considered to have the worst conditions were evaluated on-site by a team of senior personnel in mid-1995. Environmental health problems were prevalent and often serious: over one-third of the communities had water supply or sanitation problems and 70 per cent had housing problems, with overcrowding and substandard housing being commonplace. Thirty-six per cent had difficulties with waste water disposal, 37 per cent had no rubbish disposal, and in others, the methods of disposal were often inadequate; pests were problems in 44 per cent of communities and the hygiene and maintenance of communal toilets was unacceptable in 25 per cent. Seventy-two per cent had no on-site environmental health worker and 44 per cent had no on-site or visiting medical, nursing or health worker personnel. An action plan was developed and the highest-priority communities were targeted in a program of major works (for example, housing, drainage and sewerage) and minor works, which have been commenced. The remote-area environmental health workers' program is being expanded. Increased intersectoral collaboration and enhanced community involvement in decision making have occurred as a result of this work.

Child Welfare↗
PubMed1997

Integrating information technology with an outcomes management program.

Health care changes are occurring rapidly. How successfully an institution keeps up with these changes depends on information and evaluation of outcomes of care. This article discusses how information technology is linked with outcomes management and measurement, types of data, development of data sets, quality issues related to data, and issues that must be addressed as computerized patient records become a reality. By incorporating information technology with outcomes measurement, a new era of outcomes management will be reached.

Case Management↗