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Biomedical subjects

A Lennox

Publications and source records attributed to A Lennox.

At least 19 recordsLinked to original sources
PubMed2002

Flight microangiopathy in medium-to-long distance flights: prevention of edema and microcirculation alterations with HR (Paroven, Venoruton; 0-(beta-hydroxyethyl)-rutosides): a prospective, randomized, controlled trial.

This study evaluated the effects of HR (Paroven, Venoruton; 0-(beta-hydroxyethyl)-rutosides) on the prevention and control of flight microangiopathy, and particularly on edema, in subjects with varicose veins flying for more than 7 hours. Forty patients with varicose veins, edema, and initial skin alterations due to chronic venous hypertension were included. Measurements of skin laser Doppler flowmetry resting flux, Po(2) and rate of ankle swelling, were made before and after the flights (within 4 hours before the flights and within 2 hours after the flights). The length of the flights was between 7 and 9 hours; all seats were in coach class. The 2 groups were comparable for distribution. The variation of Po(2) was significant in both groups. However, in subjects treated with HR, the decrease in Po(2) was smaller (P < 0.05). The decrease in laser Doppler flowmetry resting flux was also significant in both groups, with a higher flux at the end of the control period in the treated subjects (P < 0.05). The venoarteriolar response progressively decreased at 7 and 9 hours. The decrease was less evident in the treatment group (P < 0.05). The rate of ankle swelling was progressively increased in the control group; the increase was not significant in the HR group. In long-haul flights, HR is useful for reducing the increased capillary filtration and in controlling edema in patients with venous hypertension and is effective in controlling perfusion disorders and microangiopathy, particularly swelling and edema, due to flights.

Adult↗
PubMed2001

Flight microangiopathy in medium- to long-distance flights: prevention of edema and microcirculation alterations with total triterpenic fraction of Centella asiatica.

The aim of this study was the evaluation of microcirculatory alterations associated with edema in passengers travelling for more than 3 hours and the study of the effects of TTFCA (total triterpenic fraction of Centella asiatica) on the development of microcirculation alterations and edema, in a prospective, randomized study. Laser Doppler flowmetry (LDF), transcutaneous PO2 and PCO2, rate of ankle swelling (RAS) were used. Subjects were randomized after informed consent into two groups: one control group (no drug or other treatment), and a treatment group (TTFCA 60 mg thrice daily for 2 days before the flight, the day of the flight, and for another day after the flight). Inclusion criteria were age range between 30 and 50, mild-moderate superficial venous disease with varicose veins. Subjects traveled in economy class. In controls there was a progressive increase in CO2, RAS, and edema score and a progressive decrease in flux (RF) and venoarteriolar response with flying time. The variations in all parameters were milder (p>0.05) in the TTFCA group. RAS and edema were significantly lower in the TTFCA-treated group (p<0.025). The progressive increase in RAS, PCO2, and the decrease in VAR and O2 were linearly associated with flight time (up to 10 hours). These results are very interesting and indicate an option for patients prone to edema and microcirculation disturbances during long flights.

Adult↗
PubMed2000

Tissue response to an expanded polytetrafluoroethylene external valve support device: a histologic study in dogs.

Expanded polytetrafluoroethylene (ePTFE) external valve support devices (EVS) have been used successfully in patients to restore valve function in leg veins with incompetent valves when incompetence is due to dilatation of the vein walls or elongation of the valve leaflet edges. To assess tissue response to these devices, the authors implanted 12 of them in dogs, wrapping the devices around veins in the head and neck. The dogs recovered from the implantation procedure uneventfully, and the veins remained patent on color flow Doppler scanning. Gross and histologic evaluations of vein segments and attached EVS devices after sacrifice of the dogs 30 days postoperatively showed that the ePTFE devices did not affect vein patency or the cellular composition or architecture of vein walls. There were no adverse tissue reactions to the EVS and no thrombus formation in the veins to which the EVS had been applied. Tissue attachment to the EVS was apparent in all specimens. These histologic results support clinical experiences indicating that the ePTFE EVS device is safe to use in external valvuloplasty for the treatment of venous incompetence.

Animals↗
PubMed2000

Vascular screening in andropause: non-invasive investigations in vascular disease screening.

Erectile dysfunction (ED) can be associated with atherosclerotic disease. It is therefore important to be able to evaluate the extent of arterial disease. This includes subclinical arterial disease. We have developed a score based on high-resolution-B-mode ultrasound scanning of the carotid-femoral bifurcations. This is a cost-effective screening procedure that correlates well with the risk of cardiovascular events. The penile circulation can also be investigated to assess local circulation and the level of fibrosis. During this investigation it is worthwhile evaluating the carotid-femoral arteries because the risk factors that predict ED are the same as those for atherosclerosis. Penile fibrosis contributes to the pathogenesis of ED. Whether this change is associated with hypertension needs to be established by further studies.

Arterial Occlusive Diseases↗
PubMed2000

Microcirculatory studies in erectile disorders.

Local microcirculatory disturbances and fibrosis are thought to contribute to the pathogenesis of erectile dysfunction (ED). The assessment of these disturbances is now possible using non-invasive techniques such as laser Doppler flowmetry (LDF) and measuring transcutaneous pO2 and pCO2. However, these techniques need standardisation (e.g. in terms of equipment, conditions in which the examination is carried out and duration of measurement). Nevertheless, these techniques have a qualitative value. Marked alterations are seen in smokers and hypertensive patients. LDF has also been used to monitor the effect of treatment (e.g. after intracavernosal PGE1). These techniques remain non-diagnostic in individual patients. However, in groups of patients they may produce useful information (e.g. to assess treatments for ED).

Blood Gas Monitoring, Transcutaneous↗
PubMed2000

[Femoral artery pseudo-aneurysms--changes in treatment, report of 7 years].

The femoral artery remains the most used peripheral site for radiological catheter access. With a greater number of both diagnostic and therapeutic procedures being performed by interventional radiologists and cardiologists, and with larger catheters being used for stenting and endovascular grafting, the incidence of iatrogenic pseudo-aneurysms reported has reached as high as 0.5-2%. Ideally, they should thrombus spontaneously. However, when this does not occur, management options include: observation, ultrasound-guided obliterative compression, direct thrombin injection, embolization, stent graft insertion, and very rarely-surgery. During a 7-year period (1992-1999) we treated 131 cases of femoral artery false aneurysms. Until 1998 ultrasound-guided compression-obliteration, with a 95% success rate, was our method of choice. Since 1998, direct thrombin injection, with 100% success in 24 cases, has become our preferred method. It is pain-free, fully successful even in anticoagulated patients, and is currently our treatment of choice.

Aneurysm, False↗
PubMed1999

Graft dilatation following abdominal aortic aneurysm resection and grafting.

BACKGROUND: It has been suggested that graft dilatation following repair of abdominal aortic aneurysm (AAA) is associated with complications such as anastomotic aneurysm and graft rupture. The purpose of the present study was to document the degree of dilatation observed in grafts after aneurysm repair and to correlate this with any graft-related complications. METHODS: Between January 1987 and December 1992, 219 patients had elective repair of their AAA at St George Hospital. A follow-up ultrasound scan was available for 154 of these patients. The following factors were examined: age, sex, size of aneurysm, type and size of graft, time of follow-up scan, size of graft at follow-up and any graft-related complications. RESULTS: The mean graft dilatation observed in knitted grafts (42.6%; 95% CI: 39.1-46.1%) was significantly greater than that observed for woven grafts (25.5%; 95% CI: 19.0-32.1%; P < 0.0001). There were no graft-related complications. CONCLUSIONS: Graft dilatation is a predictable phenomenon following AAA repair. It is more pronounced in knitted than in woven grafts, but does not necessarily lead to graft-related complications or failure.

Aged↗
PubMed1999

Monte Carlo calculations to characterize the source for neutron therapy facilities.

Modern radiation treatment planning for photons includes full 3D modeling of the adsorbed dose distribution, accurate inclusion of the patient anatomy, and consideration of significant changes in material density and composition. Such efforts are founded in an accurate description of the radiation source and the beam delivery system. Modern fast neutron therapy facilities employ highly penetrating beams and isocentric beam delivery. Treatment planning is largely based on analytic models adapted from photon codes and interaction cross sections normalized to macroscopic attenuation. However, the recent PEREGRINE initiative at Lawrence Livermore Laboratory offers the possibility of fully stochastic modeling if the neutron source can be adequately described. In this article we report neutron source modeling of three high energy facilities. Neutron production is based on the intra-nuclear cascade model of the LAHET code while neutron transport through the beam delivery system is managed by MCNP using cross section libraries extended to 100 MeV neutron energy. PEREGRINE is then used to transport the neutron beam through typical phantoms. The resulting neutron sources are in excellent agreement with the limited experimental information and the measured phantom data are well described by the PEREGRINE transport using the LAHET/MCNP determined neutron sources.

Dose-Response Relationship, Radiation↗
PubMed1999

Comparison of low-molecular-weight heparin, administered primarily at home, with unfractionated heparin, administered in hospital, and subcutaneous heparin, administered at home for deep-vein thrombosis.

In this study, 294 patients with acute proximal DVT (deep venous thrombosis) were randomly assigned to receive intravenous standard heparin in the hospital (98 patients) or low-molecular-weight heparin (LMWH) (nadroparin 0.1 mL [equivalent to 100 AXa IU] per kg of body weight subcutaneously twice daily) administered primarily at home (outpatients) or alternatively in hospital (97 patients) or subcutaneous calcium heparin (SCHep) (99 patients, 0.5 mL bid) administered directly at home. The study design allowed outpatients taking LMWH heparin to go home immediately and hospitalized patients taking LMWH to be discharged early. Patients treated with standard heparin or LMWH received the oral anticoagulant starting on the second day, and heparin was discontinued when the therapeutic range (INR 2-3) had been reached. Anticoagulant treatment was maintained for 3 months. Patients treated with SCHep were injected twice daily for 3 months without oral anticoagulants. Patients were evaluated for inclusion and follow-up with color duplex scanning. Venography was not used. In case of suspected pulmonary embolism (PE) a ventilatory-perfusional lung scan was performed. Endpoints of the study were recurrent or extension of DVT, bleeding, the number of days spent in hospital, and costs of treatments. Of the 325 patients included, 294 completed the study. Dropouts totaled 31 (10.5%); six of the 325 included patients (1.8%) died from the related, neoplastic illness. Recurrence or extension of DVT was observed in 6.1% of patients in the LMWH group, in 6.2% in the standard heparin group, and in 7.1% in the SCHep group. Most recurrences (11/17) were in the first month in all groups. Bleedings were all minor, mostly during hospital stay. Hospital stay in patients treated with LMWH was 1.2+/-1.4 days in comparison with 5.4+/-1.2 in those treated with standard heparin. There was no hospital stay in the SCHep group. Average treatment costs in 3 months in the standard heparin group (US $2,760) were considered to be 100%; in comparison costs in the LMWH group was 28% of the standard heparin and 8% in the SCHep group. This study indicated that LMWH and SCHep can be used safely and effectively to treat patients with proximal DVT at home at a lower cost.

Ambulatory Care↗
PubMed1998

Development and evaluation of a community based, multiagency course for medical students: descriptive survey.

OBJECTIVE: To develop and evaluate an effective, community based, multiagency course (involving doctors, nurses, non-health statutory workers, and voluntary organisations) for all Leicester medical students, in response to the General Medical Council's recommendation of preparing the doctors of tomorrow to handle society's medical problems. DESIGN: Survey evaluating a task oriented, problem solving course, designed by medical students in partnership with the University of Leicester and the local community. The students, staff, and participating agencies and patients all helped in the evaluation of the first course. The students' performance on the course was also individually assessed. SETTING: Inner city housing estate with Jarman index 64.1 in Leicester. SUBJECTS: All third year medical students at Leicester University. MAIN OUTCOME MEASURES: Results of the student assignments and students' responses to a questionnaire. Results of feedback questionnaires distributed to the patients and agency representatives. RESULTS: In a two month period, 168 students completed the first course. 163 students passed the criterion referenced assignment, 50 of whom achieved an "excellent" grade. 166 completed the questionnaire, with 159 wishing to see the course continue in the present format and 149 saying that the course linked theoretical teaching with the practical experiences gained in the community. CONCLUSIONS: The University of Leicester has a viable mechanism for providing a community based, multiagency course for all its medical students. Many of the principles applied in the development and implementation of the course could be transferred to other medical schools.

Adult↗
PubMed1996

Gender in medicine: the views of first and fifth year medical students.

This study of first and fifth year medical students found a general recognition among male and female students that gender affects future career choices and the ability to reach career goals. Females were seen as being disadvantaged both in terms of career choice and their ability to achieve career goals. These views are less abstract and more based upon the reality of personal experiences in clinical attachments among fifth year students. While both male and female students describe negative experiences of clinical training, female students were more likely to suffer discrimination because of their gender in certain specialties, such as surgery, and to be dissuaded from pursuing a career in that specialty. Despite the general awareness of the effects of gender in medicine this did not appear to have an effect upon personal career choice. However, some female students were considering career choices at an early stage in their career based on accommodating their future desire to have a family life. Over half of all male and female fifth year students reported that having time for their family was an important consideration in choosing a career.

Adolescent↗
PubMed1996

Late-onset Huntington's disease: a geriatric psychiatry perspective.

Late-onset Huntington's disease is more common than has been generally appreciated and is associated with a wide range of psychiatric symptoms and syndromes. Geriatric psychiatrists have an important role to play in establishing the diagnosis and providing guidance to elderly patients and their families as they struggle with difficult management decisions. An illustrative case report and selective literature review are presented that highlight the genetic and clinical aspects of the condition.

Aged↗
PubMed1995

Gerstmann-Sträussler-Scheinker disease with mutation at codon 102 and methionine at codon 129 of PRNP in previously unreported patients.

We present two patients with Gerstmann-Sträussler-Scheinker disease (GSS), one from a previously undescribed kindred and one from the Canadian branch of a previously reported British kindred. In both patients, GSS is caused by a substitution of thymine for cytosine at codon 102 of the prion protein gene (PRNP). In each patient, we confirmed the clinical diagnosis by neuropathologic examination. The mutation, causing a substitution of leucine for proline at residue 102 (P102L) of the prion protein, has been previously reported in at least 30 other families. In the patients described here, the mutation was in coupling with methionine at PRNP codon 129.

Adult↗
PubMed1994

Molecular genetic predictive testing for Alzheimer's disease: deliberations and preliminary recommendations.

Forty-one participants representing diverse professional back-grounds attended a workshop on genetic predictive testing for familial Alzheimer's disease (FAD) on January 23, 1993 at Surrey Place Centre in Toronto, Canada. Rapidly emerging molecular genetic findings in AD indicate that predictive testing is now technologically feasible for selected individuals, although defining eligibility criteria remains problematic. Legal, ethical, biomedical, and psychosocial issues related to establishing predictive testing programs for AD were discussed at the workshop. This article reflects these discussions, provides the current biomedical background for them and examines the Huntington's disease (HD) predictive testing experience. Observations concerning molecular genetic predictive testing for AD in light of its genetic heterogeneity and clinical characteristics, such as usual later age of onset than HD, are presented. It is proposed that predictive testing for AD can now be cautiously offered in a research setting primarily according to the recommendations contained within the Ethical Issues Policy Statement on Huntington's Disease Molecular Genetics Predictive Test. However, in their application to AD, some points in the statement are considered to require emphasis, modification, or currently to be of uncertain applicability. This represents an initial step in an on-going process of debate concerning AD that will be required as new advances occur in genetic and clinical research and in bioethics.

Aged↗