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Biomedical subjects

S Andrews

Publications and source records attributed to S Andrews.

At least 19 recordsLinked to original sources
PubMed2005

The effect of baseline CD4 cell count and HIV-1 viral load on the efficacy and safety of nevirapine or efavirenz-based first-line HAART.

BACKGROUND: A substantial number of patients start their first-line antiretroviral therapy at an advanced stage of an HIV-1 infection. Potential differences between specific drug regimens in antiviral efficacy and safety in these patients are of major importance. METHODS: A post-hoc analysis within the randomized controlled 2NN trial comparing efficacy between regimes containing nevirapine (NVP), efavirenz (EFV), or both, in addition to stavudine and lamivudine. PRIMARY OUTCOME: risk of virologic failure in different strata of baseline CD4 T-lymphocyte counts and plasma HIV-1 RNA concentrations (pVL). Virologic failure: never reaching a pVL < 400 copies/ml, or a rebound to two consecutive values > 400 copies/ml. RESULTS: The risk of virologic failure was increased at very low CD4 counts (< 25 x 10(6) cells/l) compared to CD4 counts > 200 x 10(6) cells/l [hazard ratio (HR), 1.28; 95% confidence interval (CI), 0.93-1.77]. The same was seen for a pVL > or = 100,000 copies/ml compared to a lower pVL (HR, 1.20; CI, 0.96-1.50). There were no statistically significant differences between NVP and EFV in risk of virologic failure within any of the CD4 or pVL strata, although EFV performed slightly better in the low CD4 stratum. The incidence of rash in the NVP group was significantly higher in female patients with higher CD4 cell counts, while adverse events in the EFV group were not associated with CD4 cell count. CONCLUSIONS: Initial antiretroviral therapy including NVP or EFV is effective in patients with an advanced HIV-1 infection. A high baseline CD4 cell count is associated with the occurrence of rash in female patients using NVP.

Adult↗
PubMed2005

A photoelastic clinical study of the static load distribution at the stump/socket interface of PTB sockets.

It is recognized that the assessment of prosthetic socket fit is based largely on the subjective clinical judgement of the prosthetist. This study assesses a novel technique, photoelasticity, for use as a tool for the qualitative and quantitative assessment of socket fit. Photoelasticity is a visual technique that produces contours of principal stress or strain differences. The colour and/or distance between the contours can be qualitatively or quantitatively assessed, using a polariscope, to give a full-field analysis of the stresses on the sockets's surface. This paper presents qualitative photoelastic socket surface contour data gathered during several prosthesis fitting sessions for two male trans-tibial amputees. Results are compared with the actual known contact regions at the stump/socket interface to determine if a relationship exists. This comparison of results has then been used to conclude the suitability of photoelasticity as a tool for the assessment of socket fit and recommendations are made as to the future developments of the technique. A direct relationship between the stump/socket contact regions and the qualitative photoelastic contours was demonstrated. Given further development this photoelastic technique may therefore be suitable for qualitative analysis of the interactions between the stump and prosthetic socket.

Aged↗
PubMed2005

Profiling bacterial survival through a water treatment process and subsequent distribution system.

AIMS: To profile fractions of active bacteria and of bacteria culturable with routine heterotrophic plate count (HPC) methods through a typical water treatment process and subsequent distribution system. In doing so, investigate how water treatment affects both bacterial abundance and diversity, and reveal the identities of active bacteria not detected by traditional HPC culture. METHODS AND RESULTS: Profiling active fractions was performed by flow cytometric cell sorting of either membrane-intact (BacLight kit) or enzymatically active (carboxyfluorescein diacetate, CFDA) bacteria, followed by eubacterial 16S rDNA-directed PCR and denaturing gradient gel electrophoresis (DGGE). Water treatment significantly reduced active bacterial numbers detected by the BacLight kit and CFDA assay by 2.89 and 2.81 log respectively. Bacterial diversity was also reduced from > 20 DGGE bands in the active fractions of reservoir water to only two bands in the active fractions of finished water. These two bands represented Stenotrophomonas maltophila, initially culturable by HPC, and a Burkholderia-related species. Both species maintained measurable traits of physiological activity in distribution system bulk water but were undetected by HPC. CONCLUSIONS: Flow cytometric cell sorting with PCR-DGGE, to assess water treatment efficacy, identified active bacteria from a variety of major phylogenetic groups undetected by routine HPC. Following treatment S. maltophila and a Burkholderia-related species retained activity and entered distribution undetected by HPC. SIGNIFICANCE AND IMPACT OF THE STUDY: Methods used here demonstrate how water treatment operators can better monitor water treatment plant efficacy and assess distribution system instability by the detection and identification of active bacteria recalcitrant to routine HPC culture.

Bacteria↗
PubMed2004

Gastric cancer: establishing predictors of biologic behavior with use of population-based data.

BACKGROUND: Tumor thickness and nodal status are important predictors of survival following curative resection for gastric cancer. Lymphovascular invasion (LVI) is a potential predictor of biological behavior. The relationship between LVI and tumor thickness (T status) has not been established in population-based studies. METHODS: Clinicopathological and survival data of 577 patients at nine centers, from between 1991 and 1997, was collected from patient records and a Provincial Cancer Registry. The primary endpoint of the study was death. A secondary analysis of a node-negative subgroup examined the significance of LVI with respect to T status. RESULTS: The population disease-specific survival was 28%. In a multivariate analysis, T, N, M, esophageal margin, tumor morphology, and residual tumor category were independent predictors of survival. LVI was documented in 58% of resected tumors. LVI correlated with advancing T and N status but was not significant in a multivariate population model. Subgroup analysis of node-negative gastric cancer found T status and LVI to be independent predictors of survival. LVI was associated with a 5-year survival of 8%, versus 43% among patients in whom it was absent (P <.001). CONCLUSIONS: T status and N status were the most important independent predictors of survival in a population-based study of gastric cancer. LVI correlated with advancing N and T status. Multivariate analysis of node-negative patients showed LVI and T status are independent predictors of survival.

Adenocarcinoma↗
PubMed2003

The reliability of digital images when used to assess burn wounds.

Sixty burn wounds were assessed in person. The same observer later assessed them using digital images of different sizes. The file sizes tested were 2.25, 5.5 and 9 MByte per image. There was good agreement between the diagnoses of burn depth made using the digital images and those made in person, with kappa scores of 0.53-0.60. There were no major differences between the three file sizes. The assessments made of the partial-thickness burns showed a lower rate of agreement between the in-person and the digital image assessments and for these burns the 2.25 MByte images were apparently as good or better than the larger images. There was little difference between the three file sizes in terms of observer confidence, usefulness of the location shot, or perceived image quality. There was no significant advantage in using larger file sizes to assess burn wounds.

Burns↗
PubMed2003

Survival of the fittest? The scientific basis for the Royal Navy pre-joining fitness test.

The Royal Navy introduced a pre-joining fitness test to the selection procedures for RN Ratings from Summer 2003. The scientific basis for the test came from the present study to investigate if anthropometric and physical fitness measures predicted training failure. Fitness and anthropometric data from 1641 trainees were collected, together with their training outcome (i.e. pass or fail), during the period from September 2001 to March 2002. In addition, a retrospective interrogation of medical records identified those who reported any lower limb injuries. The overall rate of training attrition was 22%. Success in training was associated with: gender; age; physical fitness; and, in the case of females, Body Mass Index (BMI). The reported incidence of lower limb injury (LLI) was associated with: gender; physical fitness; and, for female trainees, BMI. The reported incidence of LLI was approximately 50% in the 'least-fit' female group compared to 10% in the 'most-fit' male group. 16% of females and 2% of males were considered 'unfit' (i.e. did not attain the prescribed run standards of 13 min 15 s and 11 min 13 s respectively). 3% of trainees were considered 'obese' (a BMI > 30 kg.m-2) whereas more than 25% were overweight (BMI > 25 kg.m-2). As a result of this work, selection candidates must now demonstrate a minimum standard of aerobic fitness prior to arrival at HMS Raleigh. The future impact of this selection measure on the reported incidence of lower limb injury and financial costs of training requires further investigation.

Adolescent↗
PubMed2002

Paroxetine-induced vaginal anaesthesia.

Antidepressant drugs cause a variety of sexual side effects such as decreased libido, impaired erection and delayed or absent ejaculation and orgasm. They cause distress, strain relationships, impair quality of life and reduce compliance to treatment. However, antidepressant-induced changes in sexual sensations are rare. Here, we report on a case of paroxetine-induced loss of sensation in the vagina.

Adult↗
PubMed2001

The alphaVbeta6 integrin regulates its own expression with cell crowding: implications for tumour progression.

Expression of the growth-promoting integrin alphavbeta6 in colon cancer cells induces gelatinase B secretion and activation, the inhibition of which abolishes alphavbeta6-mediated tumour cell growth within a collagen matrix. Herein, we show that high cell density selectively enhances alphavbeta6 expression in a protein kinase C (PKC)-dependent manner in preference to other beta integrin subunits, resulting in a marked increase in gelatinase B secretion as cells reach confluence. Moreover, PKC activity increases with cell confluence, and the rise in PKC activity is much greater for alphavbeta6-expressing cells than for colon cancer cells which lack alphavbeta6. We propose a self-perpetuating system of colon cancer progression in which the integrin alphavbeta6 provides a means of sustaining tumour cell proliferation. In this model, alphavbeta6 regulates its own expression via a PKC-mediated signalling pathway as tumour cells become crowded and quiescent. The alphavbeta6-mediated induction of gelatinase B secretion facilitates peri-cellular matrix degradation, which helps overcome crowding and restores cell proliferation.

Antigens, Neoplasm↗
PubMed2001

Distinguishing common and task-specific processes in word identification: a matter of some moment?

The same 500 words were presented in 6 different word identification tasks (Experiment 1: lexical decision, semantic categorization, and 3 speeded naming tasks; Experiment 2: delayed naming). Reaction time (RT) distributions were estimated for each task and analyses tested for the effects of word frequency and animacy on various parameters of the RT distribution. Low frequency words yielded more skewed distributions than high frequency words in all tasks except delayed naming. The differential skew was most marked for tasks that required lexical discrimination. The semantic categorization task yielded highly skewed distributions for all words, but the word frequency effect was due to shifts in the location of the RT distributions rather than changes in skew. The results are used to evaluate the relative contributions of a common lexical access process and task-specific processes to performance in lexical discrimination and naming tasks.

Adult↗
PubMed2001

Couch or crouch? Examining the prostate: a randomized study comparing the knee-elbow and the left-lateral position.

OBJECTIVE: To compare two methods of examining the prostate, the knee-elbow (KE) and left-lateral (LL) positions, to establish which allows a more complete examination, and to determine if there is any difference in patients' perception of pain or embarrassment for either method. PATIENTS AND METHODS: All men attending two urology clinics who required a prostate examination were eligible for the study. Both the KE and LL methods were used for each participant, by the same clinician. The order in which the examinations were conducted was randomized using the last digit of the patient's hospital number. RESULTS: Five clinicians examined 117 men; three patients refused to participate and the examination data were incomplete for two. Irrespective of the order in which the examinations were conducted (P = 0.6), the KE position permitted a greater proportion of the prostate to be palpated (Wilcoxon signed-ranks test, z = -4.7, P < 0.001) in 35% of patients, but there was no difference in 60%. Most patients found the examinations equally painful and embarrassing. However, for those who expressed a difference, the KE was 1.9 times more comfortable than the LL position and twice as embarrassing. CONCLUSION: The two methods of prostate examination were equal for completeness of examination, pain and embarrassment in most patients. However, the KE offers an alternative to the LL position for those patients in whom the prostate is difficult to palpate or who find the examination painful.

Adult↗
PubMed2001

Early postoperative feeding after major gynecologic surgery: evidence-based scientific medicine.

Postoperative gastrointestinal care after major gynecologic surgery has evolved considerably over the last decade. According to evidence-based scientific medicine, the following conclusions can be drawn: (1) Postoperative colonic stasis occurs after major abdominal surgery and persists for approximately 3 days (classes I and IIA). (2) Elective postoperative nasogastric decompression after major abdominal surgery is unnecessary (class I). (3) Early feeding after major gynecologic surgery results in emesis but does not increase the incidence of aspiration pneumonia, dehiscence, or intestinal leaks and decreases hospital stay (class I). (4) Slow advancement of postoperative diet after major gynecologic surgery is probably unnecessary (class III). (5) After major abdominal gynecologic surgery, there appear to be minimal medical benefits (decreased infection rate) of early postoperative feeding (class III). (6) After radical hysterectomy, postoperative bowel stimulation decreases length of hospital stay (class IIA).

Diet↗
PubMed2000

Prenatal sickle cell screening education effect on the follow-up rates of infants with sickle cell trait.

OBJECTIVE: To assess the effect of prenatal education about newborn sickle cell screening on parents' compliance with the follow-up for infants with sickle cell trait. SUBJECTS: Expectant mothers whose prenatal education included information about newborn sickle cell screening were the study group, and those whose prenatal education did not include such information were the control group. METHODS: Mothers of infants with sickle cell trait were given the opportunity for in-person notification of screening results and follow-up counseling/education. Follow-up rates, anxiety and retention of information were assessed for the case-control study. RESULTS: There were a total of 15,670 infants born in the region, and 647 infants were identified with sickle cell trait. The follow-up rate for parents of infants with sickle cell trait was significantly higher (76%) for study group than the control group (49%) (P = 0.0006). Parents whose prenatal education included sickle cell hemoglobinopathy information retained significantly more of the information given during the post-natal education than did controls. CONCLUSION: Our data suggest that prenatal education for expectant mothers which includes information about newborn sickle cell screening significantly increases the follow-up rate for infants with sickle cell trait and contributes to a greater retention of information.

Adult↗
PubMed2000

Developments in the trans-tibial prosthetic socket fitting process: a review of past and present research.

A revolution in trans-tibial prosthetic design began at the end of World War II with the development of new materials and a dramatic improvement in the understanding of biomechanics. Early research was based mainly on the improvement of existing prosthetic design practice. Today, research has been focused on providing a better understanding of stump/socket interface biomechanics and improving socket fit by attempting to quantify the normal/direct stresses at the interface. The purpose of this review paper is to question whether research and prosthetic education/training to date has significantly improved our understanding of what makes a good socket. Although there is no doubt that advances in socket fitting techniques have been made what is not clear is the actual extent to which these advances have improved the quality of sockets fitted. It is suggested that a new approach is needed which can overcome some of the inherent problems of designing and manufacturing a comfortable high quality socket. It is also suggested that current research and education/training in the fields of pressure/interfacial interaction measurement and Finite Element Analysis techniques have limited potential to address many of these problems. There is also little evidence that current computer aided design systems offer any significant advantages over more conventional techniques.

Amputation, Surgical↗
PubMed2000

From hydrofluoroalkane pressurized metered dose inhalers (pMDIs) and comparability with chlorofluorocarbon pMDIs.

Fluticasone propionate pressurized metered dose inhalers (pMDIs) containing the hydrofluoroalkane (HFA) propellant, HFA 134a, are being developed to replace existing chlorofluorocarbon (CFC) pMDIs. This is part of the ongoing worldwide project to limit the damage to the earth's ozone layer. The in vivo performance and dose proportionality of fluticasone propionate HFA 134a pMDIs was examined for fluticasone propionate doses of 400, 1000 and 2000 microg using the 50, 125 and 250 microg strength pMDIs, respectively. The 125 and 250 microg strength HFA 134a pMDIs were compared with corresponding fluticasone propionate CFC pMDIs. Twenty-three healthy subjects participated in this single dose, randomized, five-way, cross-over study. Serial blood samples were collected 24 h post-dose to measure fluticasone propionate plasma concentrations. Twenty-four hour urinary-free cortisol was also measured before and after dosing. A dose-proportional increase in plasma fluticasone propionate concentrations was observed with increasing dose for the HFA 134a pMDIs. This was associated with a dose-related decrease in urinary cortisol excretion. Similar or lower fluticasone propionate systemic exposure was observed with the HFA 134a pMDIs compared to the corresponding CFC inhalers. The differences in systemic exposure observed for the HFA 134a and CFC pMDIs were too small to produce a differential effect on urinary cortisol excretion. Since fluticasone propionate has negligible oral bioavailability, the systemic exposure, which arises only from pulmonary absorption, is a measure of lung deposition. There was a good correlation between the in vitro fine particle mass produced by the different strengths and types of pMDI and the systemic exposure to fluticasone propionate. Therefore, the fluticasone propionate HFA 134a pMDI is an acceptable pharmaceutical alternative to the current CFC pMDI, producing similar lung deposition and no increase in systemic exposure at microgram equivalent doses.

Adult↗
PubMed2000

Identification and characterization of nuclease activities in anaerobic environmental samples.

DNA-degrading activity from anaerobic samples of bovine ruminal fluid, primary anaerobic digestor wastewater, freshwater sediments, and marine sediments was observed in the presence of 5 mM EDTA. Nuclease activity experiments involved exposing salmon chromosomal DNA to the environmental samples in 50 mM pH 7.2 buffer, incubating at 37 degrees C, and subjecting the products to electrophoresis. The same stock and concentration of EDTA used in these assays (5 mM) completely inhibited commercial grade DNase. Nuclease activity in two of the samples, ruminal fluid and wastewater, was further characterized. DNA degradation in the ruminal sample was significantly reduced when EDTA or citrate concentrations were increased to 50 mM or above. DNA degradation activity in ruminal fluid was associated with material that passed through a 0.22-micron filter, but wastewater activity was associated with material retained by a 3-micron filter. Degradation activity in the wastewater was resistant to heat pretreatment, whereas the rumen activity was heat-labile (70 degrees C, 60 min). These results demonstrated the biochemical complexity of these two environments and that high molecular weight DNA has a short half-life in these anaerobic environments.

Anaerobiosis↗