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Biomedical subjects

M Townsend

Publications and source records attributed to M Townsend.

At least 37 records · Page 2Linked to original sources
PubMed1998

A new technique of intraprostatic fiber placement to minimize thermal injury to prostatic urothelium during indigo interstitial laser thermal therapy.

A new technique of cystoscopic insertion of laser fiber into the prostate is described for interstitial laser thermal therapy in the treatment of benign prostatic hyperplasia. The technique uses the inherent physical properties of the fused silica laser fiber with the assistance of a standard cystoscope to insert the laser fiber into the inner region of the prostate gland. Laser thermal therapy is subsequently maintained within the inner prostate at a distance from the prostatic urothelium. The technique described is simple, safe, and minimizes the potential for thermal injury to the prostatic urothelium.

Burns↗
PubMed1998

The monoclonal antibody HB1 recognizes an adhesion molecule for macrophages in the brain.

The brain environment exerts a powerful influence on macrophage phenotype, as exemplified by microglia, but the mechanisms mediating this control are nuclear. Since adhesion molecules are known to transmit signals across cell membranes, we investigated adhesion receptors involved in macrophage interaction with brain tissue. We have demonstrated previously that macrophages adhere specifically to CNS neurones in an in vitro assay. Here we show that this adhesion is inhibited by lectins, including Griffonia simplicofolia isolectin B4 (GSI), which has been used as a microglial marker for many years. Adhesion is unaffected by antibodies to several known adhesion molecules but is markedly inhibited by a new monoclonal antibody: HB1. HB1 recognizes microglia in the normal brain and activated microglia and recruited monocytes during CNS pathology. It labels a subset of resident macrophages and recruited monocytes in other tissues. Using this antibody, we isolated a protein of about 110 kDa from macrophage cell lysates. This protein is recognized by GSI, providing the first evidence of a functional role for the antigen labelled by this lectin. Further study of the HB1 antigen may provide important information about the influence of the brain environment on the phenotype of monocytic cells.

Animals↗
PubMed1998

Cooperative learning and social acceptance of children with mild intellectual disability.

The effects of the participation of non-disabled children in a cooperative learning programme on their social acceptance of classmates with mild intellectual disability was examined. A sample of 24 children with mild intellectual disability in the 9-11-year-old age-range was identified from educational psychologists' case records. All of the children were receiving mainstreaming special education programmes at the time of the study. Twelve of the children had previously attended special education classes, while the remainder had always attended regular classes. Half of the children's regular classes were randomly assigned to either receive an experimental cooperative learning programme or to serve as control classrooms. The non-disabled children in the experimental classes showed significant increases in their social acceptance (sociometric ratings) of the children with mild intellectual disability, both immediately following the programme and 5 weeks later, but no such increases were evident in the children in the control classrooms. This pattern held for both the former special class pupils and the children with mild intellectual disability who had never attended special classes. The results confirm the usefulness of cooperative learning strategies for enhancing the social acceptance of children with mild intellectual disability in mainstreaming special educational programmes, regardless of the nature of their previous special educational provisions.

Child↗
PubMed1997

Ultrasound evaluation of blunt abdominal trauma: program implementation, initial experience, and learning curve.

OBJECTIVE: Although sonographic screening for blunt abdominal trauma is gaining acceptance, standards for implementation, training, credentialing, and quality control remain to be established. DESIGN: This prospective study examines a Level I trauma service experience with the de novo establishment of a trauma ultrasound (US) program credentialed through the Department of Surgery under the auspices of Continuous Quality Improvement. MATERIALS AND METHODS: All trauma surgeons attended a combined didactic and "hands on" 8-hour trauma US course. Abdominal sonography was subsequently performed on patients with potential blunt abdominal trauma followed by a standard diagnostic evaluation, which included computed tomographic scan, diagnostic peritoneal lavage, or observation. MEASUREMENTS AND MAIN RESULTS: Three hundred patients were studied over a 4-month period. They averaged 35 years of age with an average injury severity score of 12. The time required to perform the US examination averaged less than 3 minutes. Standard diagnostic evaluation included computed tomographic scan (21%), diagnostic peritoneal lavage (45%), and observation (34%). US examinations resulted in 277 true negatives, 17 true positives, two false positives, and four false negatives for a sensitivity of 81.0%, a specificity of 99.3%, and an accuracy of 98.0%. Annualized cost savings with the use of US evaluation versus standard diagnostic evaluation would amount to over $100,000.00. CONCLUSIONS: This experience with the de novo implementation of a trauma US program suggests that the training and credentialing requirements in this study are sufficient to provide surgeon ultrasonographers with acceptable competence in US diagnosis of blunt abdominal trauma.

Abdominal Injuries↗
PubMed1997

Adhesion molecules involved in macrophage responses to Wallerian degeneration in the murine peripheral nervous system.

When a peripheral nerve is damaged the severed axon undergoes Wallerian degeneration. The distal nerve is infiltrated by large numbers of monocyte-derived macrophages which participate in the phagocytosis of degenerating myelin. In other tissues, adhesion molecules play a crucial role in leukocyte recruitment during inflammation. Blood-borne cells enter damaged tissue by interacting with adhesion molecules expressed on activated endothelium. Having crossed the endothelium, leukocytes must adhere and migrate within the tissue. We investigated the adhesion molecules involved in both stages of the macrophage response to transection of one sciatic nerve of BALB/c mice. By injecting monoclonal antibodies in vivo, before and after peripheral nerve injury, we showed that intercellular adhesion molecule-1 (ICAM-1) and integrins alpha4beta1 (VLA-4) and alphaMbeta2 (type 3 complement receptor) are unlikely to be involved in the transendothelial migration of monocytes responding to peripheral nerve degeneration. We also studied the adhesion of macrophages within the endoneurium, using an in vitro adhesion assay. Macrophages showed much greater levels of adhesion to cryostat sections of transected nerves than to control nerves. This increased adhesion was partially inhibited by antibodies to the beta1-integrin chain, and more strongly inhibited by the extracellular matrix molecules fibronectin and collagen. Adhesion was unaffected by laminin-1 and by antibodies to other adhesion molecules, including alpha4beta1- and alpha5beta1-integrins. Thus we conclude that monocyte entry into a degenerating peripheral nerve is independent of alphaLbeta2/alphaMbeta2-ICAM-1 or alpha4beta1/VCAM-1 interactions, and that adhesion within the endoneurium is mediated in part by a beta1-integrin other than alpha4beta1 or alpha5beta1.

Animals↗
PubMed1996

Measuring quality of life in the parents of children with asthma.

Parents and primary caregivers of children with asthma are limited in normal daily activities and experience anxieties and fears due to the child's illness. We have developed the Paediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ) to measure these impairments. The objective of this study was to evaluate the measurement properties of the PACQLQ. A 9-week single cohort study was conducted with assessments at 1, 5 and 9 weeks. Participants in the study were primary caregivers of 52 children (age 7-17 years) with symptomatic asthma, recruited from notices in the local media and paediatric asthma clinics. Caregivers completed the PACQLQ, Impact-on-Family Scale and Global Rating of Change Questionnaires. Patients completed the Paediatric Asthma Quality of Life Questionnaire and an asthma control questionnaire. Spirometry and beta-agonist use were recorded. The PACQLQ was able to detect quality of life changes in those caregivers who changed (p < 0.001) and to differentiate these from the caregivers whose quality of life remained stable (p < 0.0001). The PACQLQ is reproducible in subjects who are stable (ICC = 0.84), and showed acceptable levels of longitudinal and cross-sectional correlations with the child's asthma status and health-related quality of life and with other measures of caregiver health-related quality of life. The PACQLQ functions well as both an evaluative and a discriminative instrument.

Adolescent↗
PubMed1996

Measuring quality of life in children with asthma.

The Paediatric Asthma Quality of Life Questionnaire contains 23 items that children with asthma have identified as troublesome in their daily lives. The aim was to evaluate the measurement properties of the questionnaire. The study design consisted of a 9 week single cohort study with assessments at 1, 5 and 9 weeks. Patients participating in the study were fifty-two children, 7-17 years of age, with a wide range of asthma severity. At each clinic visit, a trained interviewer administered the Paediatric Asthma Quality of Life Questionnaire, the Feeling Thermometer, a clinical asthma control questionnaire and measured spirometry. For 1 week before each clinic visit, patients recorded morning peak flow rates, medication use and symptoms in a diary. The Paediatric Asthma Quality of Life Questionnaire was able to detect quality of life changes in those patients who altered their health status either as a result of treatment or natural fluctuations in their asthma (p < 0.001) and to differentiate these patients from those who remained stable (p < 0.0001). It was reproducible in patients who were stable (ICC = 0.95), which also indicates the instrument's strength to discriminate between subjects of different impairment levels. The questionnaire showed good levels of both longitudinal and cross-sectional correlations with the conventional asthma indices and with general quality of life. The results were consistent across individual domains and different age strata. The Paediatric Asthma Quality of Life Questionnaire has good measurement properties and is valid both as an evaluative and a discriminative instrument. It captures aspects of asthma most important to the patient and adds additional information to conventional clinical outcomes.

Adolescent↗
PubMed1996

Public perceptions of an appropriate donor card/brochure.

Donor card/brochures have not had a major impact on donation, though considerable resources have been invested in their development and distribution. One reason for this may be that they have not been evaluated by the people expected to sign them: the American public. A focus group format was used to develop a quantitative survey to assess the public's perception of an appropriate donor card/brochure. Several donor card/brochures were studied to compare and evaluate their effectiveness, content, format, and acceptance of the message. A donor card/brochure was designed that was based on the results of the survey: it included a business reply card for further evaluation. The newly developed donor card/brochure continues to be viewed positively by those returning business reply cards. Most have signed the card and discussed donation with family members.

Attitude to Health↗
PubMed1995

Intracranial pressure changes induced during papaverine infusion for treatment of vasospasm.

The authors reviewed the cases of 21 patients who received intraarterial infusions of papaverine to determine the drug's effects on intracranial pressure (ICP), mean arterial blood pressure, pulse rate, and cerebral perfusion pressure (CPP). The study focused on patients with aneurysmal subarachnoid hemorrhage who developed clinical signs and symptoms of vasospasm, which was documented by cerebral angiography. In 18 patients, an average dose of 300 mg papaverine was administered over 20 to 35 minutes using a No. 5 French catheter inserted into the high cervical internal carotid artery or vertebral artery. Two other patients received superselective infusions via a microcatheter placed in the anterior cerebral artery. Sixteen patients (76%) experienced good angiographic results, and 11 (52%) obtained objective clinical improvement within 48 hours. Significant elevations in ICP, blood pressure, and pulse rate were noted during papaverine infusion. In contrast, no statistically significant sustained change in CPP was observed, although it tended to decrease during papaverine infusion. In one elderly patient, infusion of the common carotid artery resulted in profound bradycardia and hypotension with a subsequent significant increase in ICP and a marked decrease in CPP. The increase in ICP in these patients correlates well with changes seen in animal models and is probably related to increased cerebral blood flow. A careful, titrated infusion of papaverine, with constant reference to the patient's ICP, blood pressure, and pulse rate, minimizes the transient increase in ICP while maintaining adequate blood pressure and CPP. Failure to monitor these parameters during the infusion, with appropriate modification of the rate of titration, could potentially produce an uncontrolled change in ICP or CPP.

Adult↗
PubMed1994

Just a glove?

Surgical gloves were introduced in the early years of this century, initially to protect nurses' and surgeons' hands from the strong antiseptic chemicals used during surgery. William Stewart Halstead is generally credited with introducing gloves to protect his scrub nurse (who later became his wife) from the carbolic acid in which the instruments were immersed. They soon became an essential requirement for asepsis and today, along with procedure gloves, are seen to protect both staff and patients from blood borne infections such as Hepatitis B and HIV. But, how many of us question the dangers posed to patients and staff through gloves? Most of us have read about the dangers of starch, but gloves may pose other significant risks to all who come into contact with them. 'With an ever increasing number of workers who don gloves as a means of personal protection, increased incidents of dermatitis, anaphylactic reactions, and respiratory problems from airborne antigens from glove powders have raised new concerns about allergies.'

Equipment Failure↗
PubMed1993

Immortalization and characterization of human cell lines with mast cell and monocytic properties.

We have previously derived a cell strain which had both mast cell and monocytic properties from the bone marrow of a child with diffuse cutaneous mastocytosis. This cell strain, termed HBM-M, consisted of two cell populations both of which possessed certain ultrastructural, cytochemical and surface phenotypic features of degranulated mast cells. The cells also displayed cytochemical and surface phenotypic features of monocytes. These cells may represent a common bone marrow derived mast cell/monocyte precursor. Studies of human mast cells have been hindered by the fact that it is difficult to establish such cells in long-term culture. Thus, we sought to immortalize HBM-M cells by introducing Simian virus 40 large T-antigen. Following transfection by the strontium phosphate technique, transformed cells were selected, expanded and passaged until the cells entered a non-proliferative phase termed crisis. Certain clones passed through crisis 3 months later and by this means two immortal cell lines, HBM-MI-1 and HBM-MI-2, were obtained. The criterion for immortality was growth for greater than 100 population doublings. The immortal cell lines retained some, but not all, of the mast cell and monocytic properties of the original HBM-M cell strain. The immortalization of the cell strain HBM-M provides an opportunity to investigate the mast cell and monocytic properties of these cells, and the apparent relationship between mast cells and monocytes.

Animals↗
PubMed1993

Entomologic investigations of an epidemic of St. Louis encephalitis in Pine Bluff, Arkansas, 1991.

An epidemic of St. Louis encephalitis (SLE) occurred in Jefferson County, Arkansas during July-August 1991. At least 26 human cases were involved, with 25 cases in the town of Pine Bluff. Twelve isolates of SLE virus were obtained from mosquitoes collected in Pine Bluff between August 13 and 24: 11 from pools of Culex pipiens quinquefasciatus, resulting in a minimum infection rate of 1.6 per 1,000 (n = 6,768) for this subspecies, and one isolate from a pool of 22 mosquitoes identified as Cx. (Culex) spp. Three of the SLE-positive pools, two from Cx. p. quinquefasciatus and one from Cx. (Cux.) spp., also yielded isolates of Flanders virus. Larval surveys resulted in the collection of seven species in four genera from 28 larva-positive habitats and the identification of one significant site of Cx. p. quinquefasciatus production. Ecologic assessments conducted at 12 randomly selected residences resulted in the identification of 17 larva-positive habitats, for an average mosquito-positive habitat rate of 1.4 per residence, and a Cx. p. quinquefasciatus larva-positive habitat rate of 0.6 per residence. Aedes albopictus and Cx. p. quinquefasciatus were the species most frequently encountered in larval surveys in residential neighborhoods.

Aedes↗
PubMed1993

Avian hosts of St. Louis encephalitis virus in Pine Bluff, Arkansas, 1991.

An investigation of the extent of St. Louis encephalitis (SLE) virus activity in the avian population in Pine Bluff, Arkansas was conducted from August 30, 1991 through September 5, 1991, following an SLE epidemic that resulted in 25 human cases. A total of 363 birds of 33 species were captured with ground-level mist nets at four sites along the northern edge of the city. No viruses were isolated from the serum of these birds, but 91 birds (25%) of 11 species had detectable neutralizing antibody against the TBH-28 strain of SLE virus in the constant-virus, serum-dilution, plaque-reduction neutralization test in Vero cell culture. No antibody to eastern equine encephalitis virus was detected. The prevalence of antibody to SLE virus varied among the sites from 11% to 44%, but the prevalence at each site was influenced by the avian species composition. The two most abundant species captured in the city, the American robin (43%) and house sparrow (42%), also had the highest prevalence of antibody. Nine other bird species were serologically positive but at significantly lower rates than for the abundant species. The antibody prevalence was higher in immature birds (27%) than in adult birds (15%), but the antibody titers were higher in adult birds than in immature ones. The overall SLE antibody prevalence and the prevalence for house sparrows were significantly higher than the average prevalence for avian hosts studied during previous SLE epidemics. Therefore, house sparrows would be a good choice for a local sentinel species.

Animals↗
PubMed1993

Cardiac transplantation (2). Psychological aspects.

In my previous article I looked at the quality of life that cardiac transplant patients have both before and after the actual operation. The quality of these patients' lives is, in nearly every case, extremely poor. Most (97%) are unable to work or even do everyday tasks such as housework, cooking and so on. A large number are housebound. Many of them confined to sleeping on the ground floor as climbing stairs is impossible to them. This, along with the knowledge that they face death without a transplant, has a profound effect on their mental state.

Activities of Daily Living↗
PubMed1991

Overexpression of the retinoblastoma gene in a familial adrenocortical carcinoma.

Tumors derived from a Li-Fraumeni syndrome cancer-susceptible family were examined for expression of the retinoblastoma susceptibility gene (RB). Whereas RB expression was normal in a primary breast carcinoma and its metastases from one member of this family, overexpression of RB was found in an adrenocortical carcinoma from another family member. This was in contrast to normal RB expression in normal tissue of this patient, the adrenocortical adenocarcinoma cell line SW-13, and the fibroblast cell line MRC-5, and low level RB expression in normal adrenal tissue. The overexpression in the adrenocortical carcinoma resulted in increased synthesis of the RB-encoded protein and did not appear to be associated with RB amplification or rearrangement. This result is novel as it is usually the loss of expression or production of an altered RB transcript exhibiting deletions that is associated with carcinogenesis. In light of the recent discovery of p53 point mutations in the affected Li-Fraumeni syndrome family members tested, RB overexpression may constitute a secondary event in Li-Fraumeni syndrome tumorigenesis.

Adrenal Cortex Neoplasms↗
PubMed1991

Measuring functional status in chronic lung disease: conclusions from a randomized control trial.

The optimal method of assessing the effect of treatment on the day-to-day function of patients with chronic airflow limitation has not yet been established. Therefore, we examined the performance of the 6-min walk test, a rating of dyspnea following the walk test, and three different questionnaires measuring dyspnea in daily activities, in a controlled trial of inhaled salbutamol and oral theophylline in 24 patients with primary fixed chronic airflow limitation. Clinically important and statistically significant effects of salbutamol and theophylline on dyspnea during the day-to-day activities were detected by each measure, but the Chronic Respiratory Questionnaire (CRQ) was more powerful than the other questionnaires, either the Oxygen Cost Diagram or the Medical Research Council Dyspnea Questionnaire as modified by the Rand Corporation. Changes in the CRQ dyspnea score showed a higher correlation with changes in spirometry, walk test score, dyspnea following the walk test, and global ratings of dyspnea than did the other two measures. We conclude that the CRQ is a responsive, valid measure of functional status for clinical trials in chronic lung disease.

Aged↗