Biomedical subjects

A Page

Publications and source records attributed to A Page.

At least 37 records · Page 2Linked to original sources

PubMed2000

Lasting effects of transient postinoculation tenofovir [9-R-(2-Phosphonomethoxypropyl)adenine] treatment on SHIV(KU2) infection of rhesus macaques.

SHIV(KU2) replicates to high levels in inoculated macaques and reproducibly causes an acute depletion of CD4(+) T cells. We evaluated the ability of treatment with the antiretroviral drug 9-R-(2-phosphonomethoxypropyl)adenine (PMPA; tenofovir), begun 7 days postinoculation, to inhibit viral replication and associated pathogenesis. Highly productive infection (plasma viral RNA > 10(6) copy eq/mL) was present and CD4 depletion had started when treatment was initiated. PMPA treatment was associated with a rapid decline in plasma viral RNA to undetectable levels, with parallel decreases in the infectivity of plasma and infectious cells in PBMCs and CSF and stabilization of CD4(+)T-cell levels. Viral dynamics parameters were calculated for the initial phase of exponential viral replication and the treatment-related decline in plasma viremia. Following cessation of treatment after 12 weeks, plasma viral RNA was detectable intermittently at low levels, and spliced viral transcripts were detected in lymph nodes. Although treatment was begun after viral dissemination, high viremia, and CD4 decreases had occurred, following withdrawal of PMPA, CD4(+) T-cell counts normalized and stabilized in the normal range, despite persistent low-level infection. No PMPA-resistance mutations were detected. These results validate the similar viral replicative dynamics of SHIV(KU2) and HIV and SIV, and also underscore the potential for long-term modulation of viral replication patterns and clinical course by perturbation of primary infection.

Adenine↗

PubMed2000

Role of phosphorylated p50-NF-kappaB in the ultraviolet response of mouse skin.

The skin constitutes a primary target for stimuli such as ultraviolet (UV) radiation and tumor promoters, leading to both inflammatory and altered proliferative responses. Since the nuclear factor kappaB (NF-kappaB) family of transcription factors plays a major role in these biological processes, we sought to elucidate its expression in newborn mouse skin upon UV and 12-O-tetradecanoylphorbol-13-acetate (TPA) exposures. We have identified the nuclear NF-kappaB binding activity in mouse skin as composed of p50/p65 heterodimers and p50 homodimers by supershift assays using different NF-kappaB-containing sequences. After UV exposure, but not TPA treatment, we detected increased NF-kappaB binding activity that correlated with a decrease of IkappaBalpha protein levels, although it was not accompanied by p50 or p65 translocation. Immunostaining of newborn mouse sections confirmed that p50 was predominantly localized in the cytoplasm of epidermal basal cells before and after UV treatment. By immunoblotting, we found distinct phosphorylated forms of p50 in cytoplasmic extracts, while only a hyperphosphorylated form was detected in nuclear extracts. In vitro dephosphorylation of skin extracts dramatically reduced the affinity of p50-containing dimers for DNA. Our data suggest that the NF-kappaB response of mouse skin to UV exposure, contrary to most stimuli in other tissues, implies additional mechanisms other than translocation, such as p50 phosphorylation.

Animals↗

PubMed2000

System to measure the use of the backrest in sitting-posture office tasks.

This paper presents an inexpensive and simple system to measure the way of use of the backrest. The system can be also used in field studies. It is based on a set of electrodes which, attached to the subject's back and the backrest, allows the contact area to be measured. A laboratory test was performed to validate the system. In the test the spontaneous use of the backrest in standard office chairs and tasks was studied. Four different types of backrest use have been detected, and it has been shown that they determine the lumbar curvature and pelvic inclination angles, as well as postural mobility. The comfort levels observed in the four types of backrest use were also different. Consequently, the system can be used as an indicator of back posture and comfort.

Electrodes↗

PubMed2000

Technique to measure lumbar curvature in the ergonomic evaluation of chairs: description and validation.

OBJECTIVE: To describe and validate a system to record the lumbar curvature, specially designed for the ergonomic evaluation of chairs. DESIGN: The technique consists of a flexible goniometer and requires a model of lumbar flexion (relationship between length and angle). BACKGROUND: Most of the techniques do not allow using the backrest of the chair or do not record continuously. METHODS: Precision, repeatability and reproducibility of the measurements have been analysed, as well as the lumbar flexion model. RESULTS: A suitable lumbar model of flexion and the repeatability and reproducibility errors obtained are presented. CONCLUSIONS: The linear model is a good one to represent the flexion of the lumbar spine. The measurements are reproducible and the errors are similar or lower than with conventional inclinometers. Relevance The device may help to investigate the relationship between lumbar pain and curvature, and to evaluate the lumbar curvature in sedentary work.

Analysis of Variance↗

PubMed2000

Differentiation of the epithelial apical junctional complex during mouse preimplantation development: a role for rab13 in the early maturation of the tight junction.

We have investigated the mechanisms by which the epithelial apicolateral junctional complex (AJC) is generated during trophectoderm differentiation in the mouse blastocyst using molecular, structural and functional analyses. The mature AJC comprises an apical tight junction (TJ), responsible for intercellular sealing and blastocoel formation, and subjacent zonula adherens E-cadherin/catenin adhesion complex which also extends along lateral membrane contact sites. Dual labelling confocal microscopy revealed that the AJC derived from a single 'intermediate' complex formed following embryo compaction at the 8-cell stage in which the TJ-associated peripheral membrane protein, ZO-1alpha- isoform, was co-localized with both alpha- and beta-catenin. However, following assembly of the TJ transmembrane protein, occludin, from the early 32-cell stage when blastocoel formation begins, ZO-1alpha- and other TJ proteins (ZO-1alpha+ isoform, occludin, cingulin) co-localized in an apical TJ which was separate from a subjacent E-cadherin/catenin zonula adherens complex. Thin-section electron microscopy confirmed that a single zonula adherens-like junctional complex present at the AJC site following compaction matured into a dual TJ and zonula adherens complex at the blastocyst stage. Embryo incubation in the tracer FITC-dextran 4 kDa showed that a functional TJ seal was established coincident with blastocoel formation. We also found that rab13, a small GTPase previously localized to the TJ, is expressed at all stages of preimplantation development and relocates from the cytoplasm to the site of AJC biogenesis from compaction onwards with rab13 and ZO-1alpha- co-localizing precisely. Our data indicate that the segregation of the two elements of the AJC occurs late in trophectoderm differentiation and likely has functional importance in blastocyst formation. Moreover, we propose a role for rab13 in the specification of the AJC site and the formation and segregation of the TJ.

Animals↗

PubMed2000

Physical activity patterns in normal, overweight and obese individuals using minute-by-minute accelerometry.

OBJECTIVE: To determine the levels and patterns of daily physical activity in groups of normal-weight, overweight and obese adults using uniaxial minute-by-minute accelerometry. DESIGN: Cross-sectional study of physical activity levels over a 7 day period using accelerometers programmed to collect minute-by-minute data. SETTING: Participants were recruited from large companies in Bristol and Cardiff. All meetings took place on company premises. PARTICIPANTS: One-hundred and eight participants volunteered for the study. Eighty-four (36 males, 48 females; 38.6+/-9.3 y) (mean+/-s.d. ) met the inclusion criteria for accelerometer measurements and were included in analyses. RESULTS: No significant differences in physical activity were identified between normal-weight (BMI<25) and overweight (BMI 25-29.9) participants. Obese participants (BMI>30) were significantly less active than non-obese participants (BMI< or =30) during weekdays (279.1+/-77.5 vs. 391.3+/-139.4 counts min(-1); P<0.001), weekends (222.3+/-93.9 vs. 386.2+/-177.5 counts min(-1); P<0.001) and evenings (221.1+/-126.3 vs. 380.8+/-220.7 counts min(-1); P=0.002), but not at work (307.5+/-87.2 vs 398.7+/-163.3 counts min(-1); P=0.06). Differences in activity levels between obese and non-obese participants were greater in males than females. Hour-by-hour physical activity patterns demonstrated that obese participants were less active than the non-obese for almost every hour of the weekdays and the weekend. CONCLUSIONS: Although no differences in activity emerged between overweight and normal-weight individuals, obese participants were substantially less active than the non-obese, particularly when there was a free choice of activity or no activity. The difference in activity levels was particularly pronounced in males, and unless obese individuals are compensating by lower energy intake, these activity patterns will contribute to the maintenance of or increase in the degree of obesity. Minute-by-minute accelerometry is a valuable tool for the assessment of activity patterns and may be useful to highlight periods of inactivity for intervention design.

Adult↗

PubMed2000

Improving pediatric asthma outcomes using self-management skills.

To improve pediatric asthma care in practices with limited time and staff, patients and families should be taught self-management skills to avoid crisis asthma care. A trained asthma team in a private practice setting can educate families of children with asthma. Specialized forms help the team assess a family's initial asthma knowledge, track their learning progress, and guide the staff and family during their self-management skill-development discussions. Team members ensure that the family leaves each visit with the appropriate information and skills, leading the family toward a more stable and predictable lifestyle.

Asthma↗

PubMed2000

Endoscopic plantar fasciotomy for chronic heel pain.

The purpose of our study was to determine whether endoscopic plantar fasciotomy is a safe and effective operation in this patient population. We reviewed our surgical results following endoscopic plantar fasciotomy in sixteen patients (twenty feet) with an average preoperative duration of symptoms of four years. Of the 20 feet, 9 had complete relief of pain while symptoms were improved in nine feet. One patient with bilateral symptoms had no relief in either foot. The average AOFAS hindfoot score improved from 62 to 80, a statistically significant difference. Unilateral patients did better than bilateral with no bilateral patients reporting complete resolution of symptoms. There were no iatrogenic nerve injuries. On the basis of our review, we recommend endoscopic plantar fasciotomy as an alternative to open plantar fascial release for those patients with recalcitrant heel pain.

Chronic Disease↗

PubMed1999

The impact of cultural and familial context on behavioral and emotional problems of preschool Latino children.

This study examined the impact of financial, cultural, and family variables on the incidence of behavioral and emotional problems in a group of two- and three-year-old Latino children. The vulnerability of these children to mental health problems stems from the many challenges faced by their families, especially those associated with acculturation and poverty. Results indicate that most problems experienced by the children were related to depression and social withdrawal. Children were at greatest risk whose parents had immigrated from Central America, whose families relied more extensively on internal coping strategies such as passive resignation, and whose parents were dissatisfied with their family's interactions.

Central America↗

PubMed1999

Diagnostic imaging of renal artery stenosis.

Many different imaging modalities and techniques have been used in the past for the diagnosis of renal artery stenosis. The ideal accurate, non-invasive and inexpensive diagnostic test has yet to be found but there have been promising developments during the last few years. In this review we consider in detail the use of the following tests for the diagnosis of renal artery stenosis; intravenous urography, B Mode ultrasound, Doppler ultrasound, renal scintigraphy with angiotensin-converting enzyme inhibitors, intra-venous and intra-arterial catheter angiography, computed tomographic angiography and magnetic resonance angiography. At present intra-arterial catheter angiography remains the 'gold standard' test. Magnetic resonance angiography is currently of limited availability in the United Kingdom but is the most promising new development because it is a non-invasive test which can be used to obtain both anatomical and functional information.

Diagnostic Imaging↗

PubMed1999

Characterization of two Bacillus probiotics.

Bacillus subtilis is currently used as an oral probiotic. We examined two commercial B. subtilis probiotic preparations, Enterogermina and Biosubtyl. Surprisingly, physiological and genetic characterization of the bacteria contained in each of these preparations has shown that neither contains B. subtilis.

Anti-Bacterial Agents↗

PubMed1998

Is body composition important in young people's weight management decision-making?

AIM: Young people are often seen as an important target for prevention of overweight, but we know little about the factors which are important for their weight management decisions. This study aimed to evaluate the extent to which elements of body composition and dimensions were implicated in their decisions to change their weight. PARTICIPANTS: Participants were 116 male and 126 female volunteers from a tertiary college in the south-west of England with a mean age of 17.90 (s.d. = 1.90) y. MEASURES: Body composition measures included height (m), weight (kg), waist and hip circumferences (mm), shoulder and hip girths (mm) and skinfold thicknesses (triceps, calf and subscapular, mm). Students also provided self-reported information on dietary practices they had undertaken in the last year. RESULTS: More females reported attempting weight loss in the last year compared to males (51.5 vs 17.6%), although more males reported attempting weight gain (19.3 vs 2.3%). Reported dietary strategies for both males and females centred around eating less fatty foods, eating less than usual and exercising more. However, a significant proportion of females also reported excessive strategies, such as self-induced vomiting and regular crash dieting. Results indicated that females who desired to lose weight were significantly (P < 0.05) heavier, and bigger in terms of circumferences and skeletal breadths, compared to females who did not wish to change their weight. For males, the 'weight loss' group were significantly (P < 0.05) bigger, heavier and fatter compared to the 'no change' and 'weight gain' group. For females only, the previously significant main effect for body dimensions across weight management groups (Pillais F(14,188) = 3.81, P < 0.001) was extinguished when controlling for bone dimensions (Pillais F(12,198) = 1.68, P = 0.074). CONCLUSION: These results indicate that frame size, particularly in the lower trunk, is a more important predictor of female weight management decision-making, than their levels of fatness. For males, fatness appears to drive their weight management decision-making processes to a greater extent.

Adolescent↗

PubMed1998

Application of fuzzy logic techniques for the qualitative interpretation of preferences in a collective questionnaire for users of wheelchairs.

Active participation of users in the evaluation of technical aids is essential, since they are part of the interface with the system and constitute a fundamental source of design criteria. In this study, 88 active users of wheelchairs were interviewed by means of a written questionnaire about their opinion concerning the adaptation of his/her wheelchair to the office workplace. A conceptual framework was introduced linking objective measurements of the user-wheelchair interface to the subjective preferences expressed by the user. Discriminant analysis was used in order to select and quantify the importance of the most significant factors influencing the user's opinions. Fuzzy logic was introduced for the qualitative interpretation of the relationship between those significant factors, based on an inductive algorithm for generating fuzzy rules. Fuzzy logic enables a person to model the uncertainty within the subjective formulation of knowledge or opinions. From the results, a mismatch between actual performance of conventional wheelchairs and requirements of office work became evident. The proposed methods make it possible to determine reliable rules explaining subjective preferences; thus, they provide a flexible means of interpreting user questionnaires and obtaining new design criteria.

Equipment Design↗

PubMed1997

Spinal abscess of Haemophilus paraphrophilus. A case report.

STUDY DESIGN: A case of paraspinal abscess formation from Haemophilus paraphrophilus is presented. OBJECTIVES: To describe a case of paraspinal abscess formation from H. paraphrophilus, a fastidious commensal organism of the mouth and pharynx. A precise bacteriologic identification can be difficult; techniques for such identification are discussed. SUMMARY OF BACKGROUND DATA: Spinal abscess caused by H. paraphrophilus is unusual and can be very difficult to diagnose. METHODS: The etiology, clinical presentation, technical examinations, and treatment are reviewed. RESULTS: Prolonged antibiotic treatment was curative, although surgery was considered. CONCLUSIONS: Bacteriologic diagnoses in these rare infections are difficult. Antibiotic therapy was curative in the patient described.

Abscess↗

PubMed1997

Influenza epidemics and incidence of schizophrenia, affective disorders and mental retardation in Western Australia: no evidence of a major effect.

In-utero exposure to influenza has been implicated as a risk factor for developmental CNS damage. This study tests the hypothesis that in-utero exposure to influenza: (1) in the second gestational trimester is associated with an increased risk of schizophrenia and affective psychoses; and (2) in the first gestational trimester is associated with an increased risk of mental retardation. Analysis was confined to 1852 cases on the Western Australian psychiatric case register with ICD-9 diagnoses of schizophrenia, affective psychoses, or neurotic depression (comparison group), and 804 cases on the Intellectual Handicap Register with mental retardation that were related to 82,963 'exposed' and 32,462 'non-exposed' births between 1950 and 1960 in the total population of Western Australia. The data were examined for effects associated with six influenza epidemics in the period 1950-1960. Using relative risk ratios for individual epidemics as well as Poisson regression and a proportional hazards model to examine systematic effects for the whole period, no major effect could be identified for maternal influenza on the incidence of schizophrenia, affective psychoses and neurotic depression, despite sufficient statistical power to detect an effect. However, a possible effect was found for mental retardation in males exposed in the first and second gestational trimester.

Adolescent↗

PubMed1997

Enhanced stability of uncemented canine femoral components by bone ingrowth into the porous coatings.

The following questions were answered in this study: (1) What is the initial stability of proximally porous-coated canine femoral components? (2) Does bone ingrowth occur under these conditions? (3) Is the stability enhanced by tissue ingrowth in vivo? The stability of proximally porous-coated femoral components of canine total hip arthroplasties after 6 months to 2 years of in vivo service in dogs was measured in vitro using displacement transducers under loads simulating canine midstance. This was compared with the stability of identical components under the same loading conditions immediately after implantation in vitro in the contralateral femurs. The femurs were then sectioned and bone ingrowth into the porous coatings was quantified. The results showed that immediately after implantation the implants can move as much as 50 microns, but that the bone ingrowth into porous coatings of canine femoral components can occur even under such conditions. These data also suggested that the relative motion existing at the time of insertion can be reduced to very small amounts (< 10 microns) by bone ingrowth.

Alloys↗

PubMed1997

SpoVM, a small protein essential to development in Bacillus subtilis, interacts with the ATP-dependent protease FtsH.

The spoVM gene encodes a 26-amino-acid polypeptide that is essential for spore formation in Bacillus subtilis. A transposon insertion within the spoVM open reading frame has been shown to encode a chimeric protein which is biologically inactive and produces a phenotype identical to that of a deletion and insertion mutation. A genetic approach was used to identify possible interacting proteins, and the membrane-bound FtsH protease was identified. Mutations in ftsH suppressed the sporulation defect of certain spoVM mutants but not others. However, production of the mother cell sigma factors, sigmaE and sigmaK, was abnormal in the suppressed strains, and mutations in either spoVM or ftsH alone impaired sigma factor production and sporulation gene expression. Using FtsH purified from Escherichia coli, we demonstrated that in vitro (i) SpoVM inhibits FtsH protease activity and (ii) SpoVM is a substrate for the FtsH protease. We propose that during sporulation, SpoVM serves as a competitive inhibitor of FtsH activity. This interaction appears to be important for completion of the prespore engulfment step of sporulation, based on the phenotype of certain spoVM ftsH double mutants.

ATP-Dependent Proteases↗

PubMed1997

Ambulatory blood pressure monitoring in acute stroke. The West Birmingham Stroke Project.

BACKGROUND AND PURPOSE: Ambulatory blood pressure monitoring (ABPM) devices are increasingly used in the assessment of hypertension, but their value in patients after a stroke is unknown, despite the fact that hypertension is an important cause of stroke and many patients have relatively high blood pressure (BP) levels at presentation. We therefore investigated the clinical use of a 24-hour oscillometric ABPM device in patients after acute stroke. We also investigated ABPM in different types of stroke (thrombosis, hemorrhage, and transient ischemic attack) and ethnic and sex differences. METHODS: BP was measured manually with a standard mercury sphygmomanometer, and ABPM measurements were made with an oscillometric device. The first reading obtained with the ABPM device was compared with simultaneous manual BP measurements. Mean daytime and nighttime pressures were also analyzed to determine the frequency of nocturnal BP falls ("dipping"). RESULTS: We studied 86 patients (48 men; mean +/- SD age, 64.2 +/- 9.2 years) admitted with acute-onset stroke (ictus within 12 hours) in a district general hospital. Thirty-one patients (36.0%) had a previous history of hypertension. The median percentage of successful BP readings by ABPM was 92% (interquartile range, 72 to 98). There was no significant difference in manual BP levels compared with the first simultaneous systolic or diastolic ABPM measurements. Systolic BPs recorded by ABPM were significantly higher in black patients with acute stroke and in patients with intracerebral hemorrhage, who also showed a trend toward higher nocturnal BPs. There was no difference in BPs between men and women and those who were alive or dead 6 months later (P = NS). There was also no difference between mean day and night systolic BP (mean difference, 1.9 mm Hg; P = .08), although mean daytime diastolic BP was higher than mean nighttime diastolic BP (mean difference, 2.4 mm Hg; P = .01). Patients with stroke therefore demonstrated a loss of diurnal BP rhythm and may be considered "nondippers"; there was also a trend toward "reverse dipping" in patients with intracranial hemorrhage. CONCLUSIONS: This study demonstrates higher systolic BPs as recorded by ABPM (but not manually) in patients with intracerebral hemorrhage than in those with cerebral infarcts; higher levels were also found in blacks. ABPM recordings are useful in the assessment of BP in patients with stroke, who may be considered nondippers.

Black or African American↗