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Biomedical subjects

T Hewitt

Publications and source records attributed to T Hewitt.

9 recordsLinked to original sources
PubMed2003

Does hydrotherapy improve strength and physical function in patients with osteoarthritis--a randomised controlled trial comparing a gym based and a hydrotherapy based strengthening programme.

OBJECTIVE: To compare the effects of a hydrotherapy resistance exercise programme with a gym based resistance exercise programme on strength and function in the treatment of osteoarthritis (OA). DESIGN: Single blind, three arm, randomised controlled trial. SUBJECTS: 105 community living participants aged 50 years and over with clinical OA of the hip or knee. METHODS: Participants were randomised into one of three groups: hydrotherapy (n = 35), gym (n = 35), or control (n = 35). The two exercising groups had three exercise sessions a week for six weeks. At six weeks an independent physiotherapist unaware of the treatment allocation performed all outcome assessments (muscle strength dynamometry, six minute walk test, WOMAC OA Index, total drugs, SF-12 quality of life, Adelaide Activities Profile, and the Arthritis Self-Efficacy Scale). RESULTS: In the gym group both left and right quadriceps significantly increased in strength compared with the control group, and right quadriceps strength was also significantly better than in the hydrotherapy group. The hydrotherapy group increased left quadriceps strength only at follow up, and this was significantly different from the control group. The hydrotherapy group was significantly different from the control group for distance walked and the physical component of the SF-12. The gym group was significantly different from the control group for walk speed and self efficacy satisfaction. Compliance rates were similar for both exercise groups, with 84% of hydrotherapy and 75% of gym sessions attended. There were no differences in drug use between groups over the study period. CONCLUSION: Functional gains were achieved with both exercise programmes compared with the control group.

Aged↗
PubMed2001

The relative role of ErbB1-4 receptor tyrosine kinases in radiation signal transduction responses of human carcinoma cells.

Activation of the epidermal growth receptor (ErbB1) occurs within minutes of a radiation exposure. Immediate downstream consequences of this activation are currently indistinguishable from those obtained with growth factors (GF), e.g. stimulation of the pro-proliferative mitogen-activated protein kinase (MAPK). To identify potential differences, the effects of GFs and radiation on other members of the ErbB family have been compared in mammary carcinoma cell lines differing in their ErbB expression profiles. Treatment of cells with EGF (ErbB1-specific) or heregulin (ErbB4-specific) resulted in a hierarchic transactivations of ErbB2 and ErbB3 dependent on GF binding specificity. In contrast, radiation indiscriminately activated all ErbB species with the activation profile reflecting that cell's ErbB expression profile. Downstream consequences of these ErbB interactions were examined with MAPK after specifically inhibiting ErbB1 (or 4) with tyrphostin AG1478 or ErbB2 with tyrphostin AG825. MAPK activation by GFs or radiation was completely inhibited by AG1478 indicating total dependance on ErbB1 (or 4) depending on which ErbB is expressed. Inhibiting ErbB2 caused an enhanced MAPK response simulating an amplified ErbB1 (or 4) response. Thus ErbB2 is a modulator of ErbB1 (or 4) function leading to different MAPK response profiles to GF or radiation exposure.

Autocrine Communication↗
PubMed2001

Integrating baseline health status data collection into the process of care.

BACKGROUND: Health status data are an increasingly important component of outcomes assessment and can be used to facilitate quality assessment and improvement efforts. An enormous challenge to the use of health status data among hospitalized patients, however, is collecting baseline data at the time of treatment, an essential component for risk-adjusting subsequent outcomes. The Mid America Heart Institute of Saint Luke's Hospital (Kansas City, Mo), attempted to integrate the collection of health status assessments within the process of performing coronary revascularization. THE DATA COLLECTION STRATEGY: The data collection strategy was developed for each admission portalelective outpatients (admissions for same-day procedures), inpatients, and emergent cases. Health status data were collected on all patients with coronary artery disease who were receiving a percutaneous coronary intervention or coronary artery bypass graft with no disruption to physician scheduling or nursing staff. RESULTS: In general, patients were agreeable to completing the health status survey. Despite initial efforts to educate the hospital staff about the goal and purpose of health status assessment, staff members who were unaware of the uses of these data seemed to minimize their value. Providing examples of how to use these data relative to the staff member's specific occupational role facilitated buy-in for this project. EPILOGUE: After the pilot study, which lasted until June 1999, data were continually collected for 18 months, through August 2000, even with the cessation of external grant funding for this project. Baseline data collection finally stopped, primarily because of a failure to accommodate data collection into the routine flow of patient care by existing nursing staff.

Angioplasty, Balloon, Coronary↗
PubMed2001

Autistic disorder and schizophrenia: diagnostic overlaps.

Data on 14 males with autism and 14 with schizophrenia were collected to examine symptom overlap. The Structured Clinical Interview (SCID), the schedule for positive symptoms (SAPS) and the schedule for negative symptoms (SANS) of schizophrenia, the Childhood Autism Rating Scale (CARS), and the DSM-III-R were administered. On the SCID, none of the men with paranoid schizophrenia met criteria for autism while 7 of those with autism met criteria for schizophrenia, disorganized type, showing negative symptoms. In addition, 5 showed positive symptoms on the SAPS and 6 negative symptoms on the SANS. As the difference in measured nonverbal intelligence was not significant, the effects could not be attributed to it. Although the findings continue to support the differentiation of autism and schizophrenia, they are also consistent with a comorbidity of the two disorders, mainly in those diagnosed with autism.

Adolescent↗
PubMed2000

Proinflammatory consequences of transgenic fas ligand expression in the heart.

Expression of Fas ligand (FasL) renders certain tissues immune privileged, but its expression in other tissues can result in severe neutrophil infiltration and tissue destruction. The consequences of enforced FasL expression in striated muscle is particularly controversial. To create a stable reproducible pattern of cardiomyocyte-specific FasL expression, transgenic (Tg) mice were generated that express murine FasL specifically in the heart, where it is not normally expressed. Tg animals are healthy and indistinguishable from nontransgenic littermates. FasL expression in the heart does result in mild leukocyte infiltration, but despite coexpression of Fas and FasL in Tg hearts, neither myocardial tissue apoptosis nor necrosis accompanies the leukocyte infiltration. Instead of tissue destruction, FasL Tg hearts develop mild interstitial fibrosis, functional changes, and cardiac hypertrophy, with corresponding molecular changes in gene expression. Induced expression of the cytokines TNF-alpha, IL-1beta, IL-6, and TGF-beta accompanies these proinflammatory changes. The histologic, functional, and molecular proinflammatory consequences of cardiac FasL expression are transgene-dose dependent. Thus, coexpression of Fas and FasL in the heart results in leukocyte infiltration and hypertrophy, but without the severe tissue destruction observed in other examples of FasL-directed proinflammation. The data suggest that the FasL expression level and other tissue-specific microenvironmental factors can modulate the proinflammatory consequences of FasL.

Age Factors↗
PubMed2000

Detection of serial changes in absolute myocardial perfusion with 82Rb PET.

UNLABELLED: Serial changes in myocardial perfusion may represent an important marker of disease progression or regression or the effects of therapy for patients with coronary artery disease (CAD). Quantitative methods have not been developed for the assessment of serial changes in perfusion. The objective of this study was to use receiver operator characteristic (ROC) analysis to determine the sensitivity and specificity of direct paired comparisons (DPCs) to detect changes in absolute myocardial perfusion measured with 82Rb PET. METHODS: Repeated dynamic 82Rb PET scans were obtained on 8 dogs at rest and during hyperemia induced with dobutamine (n = 4) or atrial pacing (n = 4). Radiolabeled microspheres were used to verify perfusion changes. Polar maps of absolute 82Rb retention and associated SD were estimated from the dynamic images. Paired comparisons were then performed using a t test on each of the 532 polar map sectors. Rest-rest and stress-stress differences were used to assess specificity and reproducibility, and stress-rest differences were used to assess sensitivity. RESULTS: 82Rb retention differences of 20% over baseline were detected with 85%-90% sensitivity and specificity, using the optimal DPC probability value and image smoothness. The average 82Rb retention differences correlated well with microspheres (r = 0.74; P = 0.001). Reproducibility of the mean retention values was 4.7% +/- 2.1%. As reproducibility varies, the DPC probability value can be adjusted to maintain specificity. These ROC results are directly applicable to other image modalities that produce measurements with similar SEs (3.7% +/- 0.9%). CONCLUSION: The developed method of DPCs is sensitive and specific for the detection of changes in absolute myocardial perfusion measured with 82Rb PET.

Animals↗
PubMed1992

Factors that affect depth perception in stereoscopic displays.

This study investigated several factors that affect depth perception in stereoscopic displays: half-image separation magnitude, separation direction (crossed vs. uncrossed), viewing distance, stimulus size, and exposure duration. The depth perceived under various combinations of levels of these factors was compared with depth predicted by the geometry of stereopsis. Perceived depth in the crossed-separation direction was frequently close to predictions, such that increases in separation and viewing distance produced appropriate increases in perceived depth. Depth in the uncrossed direction was frequently less than that predicted, especially for small stimuli presented at a long viewing distance, with a large half-image separation, and/or with a brief duration. Thus depth in both crossed and uncrossed directions equaled predictions only for large stimuli exposed for a long duration.

Adult↗
PubMedDate not supplied

Recent progress in engineering the Pittsburgh intravenous membrane oxygenator.

The University of Pittsburgh intravenous membrane oxygenator (IMO) is undergoing additional engineering development and characterization. The focus of these efforts is an IMO device that can supply as much as one-half basal O2 consumption and CO2 elimination rates while residing within the inferior and superior vena cavae after peripheral venous insertion. The current IMO design consists of a bundle of hollow fiber membranes potted to manifolds at each end, with an intra-aortic type balloon integrally situated within the fiber bundle. Pulsation of the balloon using helium gas and a balloon pump console promotes fluid and fiber motion and enhances gas exchange. During the past year, more than 15 IMO prototypes have been fabricated and extensively bench tested to characterize O2 gas exchange capacity, balloon inflation/deflation over relevant frequency ranges, and the pneumatics of the sweep gas pathway through the device. The testing has led to several engineering changes, including redesign of the helium and sweep gas pathways within the IMO device. As a result, the maximum rate of balloon pulsation has increased substantially above the previous 70 bpm to 160 bpm, and the vacuum pressure required for sufficient sweep gas flow has been reduced. The recent IMO prototypes have demonstrated an O2 exchange capacity of as much as 90 ml/min/m2 in water, which appears within 70% of our design goal when extrapolated to scaled up devices in blood.

Biomedical Engineering↗