Biomedical subjects

S S Shah

Publications and source records attributed to S S Shah.

At least 19 recordsLinked to original sources

PubMed1992

Attitudes of cardiothoracic surgeons in the UK to human immunodeficiency virus.

A survey was carried out into attitudes of cardiothoracic surgeons in the UK to human immunodeficiency virus type 1 (HIV-1) infection associated with clinical situations that would normally have been managed surgically with low operative mortality rates and long median survival times. The survey response rate was 72.4 per cent. In patients with acute valvular insufficiency or with continuing angina despite maximal medical therapy (unstable angina) who were HIV-1 antibody positive, 75.8 and 80.8 per cent, respectively, of surgeons would operate. If the patient had end-stage infection, acquired immune deficiency syndrome (AIDS), 29.7 per cent and 34.7 per cent, respectively, would consider surgical intervention. When asked to perform simple procedures such as open lung biopsy or pleurectomy on a patient with AIDS, more than half of surgeons would operate (52.2 and 65.6 per cent respectively). In patients with operable carcinoma of the lung and asymptomatic HIV-1 infection 52.3 per cent would operate. This fell to 15.0 per cent if the patient had a diagnosis of AIDS. The majority of surgeons (77.2 per cent) felt patients should have an HIV-1 antibody test before operation and this rose to 95.6 per cent if patients were in a high-risk group; 60.2 per cent of surgeons had changed their surgical practice to reduce the risks of blood-borne infection.

Attitude of Health Personnel↗

PubMed1992

Results of operation without adjuvant therapy in the treatment of small cell lung cancer.

The role of surgery in the treatment of small cell lung cancer remains a subject of debate. We carried out a retrospective review of 87 patients with small cell lung cancer referred to one surgeon for staging and treatment. Thirty patients (34.5%) were deemed suitable for thoracotomy. Fourteen patients had stage I disease, 5 patients had stage II disease, and 11 patients had stage III disease. Twenty-eight of the 30 patients (93.3%) went on to have surgical resection. The actual overall 5-year survival in all patients who underwent thoracotomy was 43.3%. The actual 5-year survival for patients in stages I and III was 57.1% and 55.5%, respectively. No patients with stage II disease survived 5 years. We conclude that there is a small group of patients with small cell lung cancer in whom, with careful preoperative staging, the prospects of cure by operation are similar to those with non-small lung cancer.

Adult↗

PubMed1992

HIV-1 infection and cardiothoracic surgery: the difference in attitudes between consultants and junior surgeons in the United Kingdom.

A postal survey was carried out inviting the opinions of consultant and trainee cardiothoracic surgeons on the subject of operating upon patients who are either HIV-1 antibody positive or suffer from full-blown AIDS. The questionnaire contained both cardiac and thoracic clinical situations, all of which under normal circumstances would be managed surgically with low operative mortality and long median survival. The overall response rate was 72.4%. A significantly greater number of consultants replied compared to juniors, 80% and 51.6%, respectively (P less than 0.001). In both groups, surgeons were more likely to operate upon a patient who was HIV-1 antibody positive than one who had AIDS. There were no significant differences in the replies of consultants and juniors to the clinical scenarios presented. However, a greater number of juniors admitted to modifying their surgical practice in the light of the increasing incidence of HIV-1 infection (P less than 0.001). Routine preoperative HIV antibody testing was advocated by 77.8% of consultants and 75% of juniors and this rose to 95.1% and 97%, respectively, if patients were in the traditionally high risk groups. Four consultants admitted that they were already performing routine preoperative HIV antibody screening. This survey emphasized the real concern amongst cardiothoracic surgeons, irrespective of their grade, about HIV-1 infection and the need for both education and clear policy guidelines to deal with this difficult issue.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Low-dose methotrexate therapy for ocular inflammatory disease.

BACKGROUND: Methotrexate is a second-line anti-inflammatory agent used in the treatment of rheumatic diseases. At low doses (12.5 mg/week), it is associated with few serious side effects. METHODS: Twenty-two patients (5 men, 17 women) with chronic noninfectious ocular inflammatory disease, who had not responded to or who had become intolerant of corticosteroid or alternate cytotoxic agents, were treated weekly with oral low-dose, pulse methotrexate. Treated diseases included chronic uveitis-vitreitis (9), scleritis (4), inflammatory pseudotumor (3), orbital myositis (3), and retinal vasculitis (3). RESULTS: Follow-up ranged from 2 to 39 months (mean, 11 months). Response time ranged from 3 to 9 weeks (mean, 5 weeks) after implementation of methotrexate therapy. Sixteen of 22 patients had reduction of inflammatory activity. Fourteen of these 16 patients were able to taper or discontinue corticosteroid therapy. Five patients had complete remission of their disease; six patients did not respond to methotrexate. CONCLUSION: Treatment with low-dose methotrexate appears to be effective therapy for steroid-resistant ocular inflammatory disease.

Adolescent↗

PubMed1992

Open lung biopsy: a safe, reliable and accurate method for diagnosis in diffuse lung disease.

The ideal method for obtaining lung tissue for diagnosis should provide high diagnostic yield with low morbidity and mortality. We reviewed all 432 patients (mean age 55 years) who underwent an open lung biopsy at this hospital over a 10-year period. Twenty-four patients (5.5%) were immunocompromised. One hundred and twenty-five patients were on steroid therapy at the time of operation. Open lung biopsy provided a firm diagnosis in 410 cases overall (94.9%) and in 20 out of 24 patients in the immunocompromised group (83.3%). The commonest diagnosis was cryptogenic fibrosing alveolitis (173 patients). Twenty-two patients (5.1%) suffered complications following the procedure: wound infection 11 patients, pneumothorax 9 patients and haemothorax 1 patient. Thirteen patients (3.0%) died following open lung biopsy, but in only 1 patient was the death attributable to the procedure itself. We conclude that open lung biopsy is an accurate and safe method for establishing a diagnosis in diffuse lung disease with a high yield and minimal risk.

Adolescent↗

PubMed1991

Development of mock circulation models for the assessment of counterpulsation systems.

STUDY OBJECTIVE: This study entailed the development of mock circulation models to assess and compare the haemodynamic efficacy of extra-aortic counterpulsation (using trained skeletal muscle wrapped around the proximal descending aorta) and conventional intra-aortic balloon counterpulsation. DESIGN AND EXPERIMENTAL MATERIALS: Hydraulic Windkessel type lumped parameter models were used either in conjunction with native skeletal muscle or as a dynamic simulation of counterpulsation. The haemodynamic performance of the wrapped latissimus dorsi muscle of the normal sheep was assessed using an artificial load to simulate the pressurised proximal descending aorta. Mock circulation models of counterpulsation comprised Windkessel compliance chambers, laminar flow resistors, a blood analogue, a prosthetic blood pump, and a purpose made hydraulic counterpulsator. MEASUREMENTS AND MAIN RESULTS: An electrically stimulated muscle wrap, 5 cm in length, previously trained for 2 weeks at 3 V and 35 Hz, was assessed for haemodynamic performance in a mock circulation: volume of fluid displaced = 14.1(SD 1.8) ml; pressure increase from 100 mm Hg = 14.9(2.1) mm Hg; external work per contraction cycle = 180(70)mJ; external mean power = 800(100) mW. In a simulation of intra-aortic balloon counterpulsation, haemodynamic benefit (ie, an increase in proximal flow rate and endocardial viability ratio and a reduction in left ventricular stroke power) was assessed with respect to defined parameters. CONCLUSIONS: This paper demonstrates the potential of the mock circulation models both for the investigation of muscle wrap performance and for the comparison of extra-aortic muscle with intra-aortic balloon counterpulsation.

Counterpulsation↗

PubMed1989

Differing effects of apical and basolateral adenosine on colonic epithelial cell line T84.

Adenosine and its agonists, 5'-(N-ethylcarboxamido)adenosine and N6-(D-2-phenylisopropyl)-adenosine, induced a sustained increase in chloride secretion when added to either the apical or basolateral aspect of monolayers of the human colonic epithelial cell line T84. Secretion was induced with identical kinetics by addition to both sides, but apical addition was less potent. The rank order of potency of the agonists on either side was consistent with the presence of an adenosine A2-receptor, but the apical and basolateral receptors differed in both their ability to stimulate increases in adenosine 3',5'-cyclic monophosphate, and their susceptibility to down-modulation by chronic exposure to 5'-(N-ethylcarboxamido) adenosine in culture.

Adenosine↗

PubMed1988

The evolution of argon laser photocoagulation scars in patients with the ocular histoplasmosis syndrome.

In 34 patients (35 eyes) with successfully treated histoplasmic choroidal neovascular membranes with a mean follow-up of 10.1 years, neither the neovascular membrane size nor the distance to the center of the foveal avascular zone (FAZ) affected final visual acuity. For a subgroup of 18 patients who had a two-year follow-up visit, the average chorioretinal scar expanded in area 50.1% per year for the first two years and 4.6% per year thereafter. This corresponded to a migration rate toward the FAZ of 152 micron/y for the first two years and 22 micron/y thereafter. After ten years, the average scar was 3.23 times larger than the initial treatment area and 480 micron closer to the FAZ than the initial treatment edge. Of the eight patients whose scars expanded to involve the center of the FAZ, six had final visual acuities either equal to or better than the initial visual acuities.

Adult↗

PubMed1988

Biomechanics of the arterial wall under simulated flow conditions.

A perfusion apparatus is employed to reproduce quantifiable pulsatile hemodynamics within freshly excised canine carotid arteries. From measurements of pulsatile intraluminal and transmural pressure and the dynamic radial motion of the vessel wall, calculations are made of the vascular incremental modulus of elasticity and hoop, axial, and radial wall stresses. The results of this investigation suggest that an increase in transmural pressure from 120/80 to 240/120 mmHg produces a marked elevation in incremental modulus and arterial wall stress. These parameters are reduced when transmural pressure is lowered while maintaining intraluminal pressure at physiologic values.

Animals↗

PubMed1983

Bloodless evaluation of blood oxygenators.

Evaluation of blood oxygenators using whole blood is inconvenient and expensive, although it is the ultimate preclinical test. Sodium sulfite solutions have advantages over blood for studying oxygen uptake: They are inexpensive, fewer variables need control, and deoxygenation is unnecessary. Assays and interpretation of results are easy. The kinetics of sulfite oxidation must be fast and the concentration of sulfite must be low to emulate oxygen uptake by blood. The kinetics were studied yielding a first order rate constant in sulfite, zero order in oxygen, of 740/min. Limitations of the technique were evaluated using the experimental rate constant and an adaptation of Lightfoot's approximation. While the reaction of hemoglobin is reversible and essentially instantaneous, that for sulfite is irreversible and finite. Thus if the approach to saturation is not monotonic or if the mass transfer resistance is significantly lowered, e.g., when blood film thicknesses are thinner than a few hundred microns, deviations may occur. Two TMO oxygenators and several prototypes were tested, with both sulfite and bovine blood. Uptakes of oxygen were comparable and the effect of parameter variations were similar. The use of sulfite for early evaluation of oxygenators is concluded to be very useful.

Animals↗

PubMed1983

Breathlessness and exercise tolerance in chronic airflow obstruction: 2-hourly versus 4-hourly salbutamol by inhalation.

Breathlessness, exercise tolerance, and spirometry were measured in 12 patients whose major symptom was breathlessness, secondary to severe chronic airflow limitation, during a double-blind crossover comparison of inhaled salbutamol in two dosages (200 micrograms 4-hourly and 200 micrograms 2-hourly) with placebo. Daily visual analogue scores of breathlessness, exercise tolerance and spirometry were all significantly improved with salbutamol in both dosages compared to placebo. The 2-hourly regimen was superior to the 4-hourly regimen only in terms of exercise tolerance. Walking distance had deteriorated significantly 2 hours after salbutamol on the 4-hourly regimen and was usefully increased by an extra dose of salbutamol on the 2-hourly regimen at the equivalent time, without side-effects. Salbutamol provided considerable symptomatic relief in addition to spirometric improvement in patients with chronic airflow limitation.

Aged↗

PubMed1983