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Biomedical subjects

M Adiseshiah

Publications and source records attributed to M Adiseshiah.

At least 55 records · Page 3Linked to original sources
PubMed1990

Increase in middle cerebral artery velocity on breath holding: a simplified test of cerebral perfusion reserve.

Resting middle cerebral artery velocity (Vmca) as well as its rate of increase on breath holding was measured on both sides in 11 age matched controls (Group I), in six symptomatic patients with unilateral internal carotid artery occlusion (Group II) and in nine symptomatic patients with unilateral internal carotid stenosis of greater than 75% (Group III), using a transcranial doppler velocimeter. There was a significantly lower resting Vmca in Group II patients on the occluded side, but not on the stenosed side in Group III, but there was considerable overlap of results. However, during breath holding, the rate of increase of Vmca allowed better separation of the occluded side (Group II) from the contralateral normal side as well as from controls, and from the stenosed side in Group III. Also there was a lower rate of rise of Vmca on the stenosed side in Group III than controls. As a test in symptomatic patients with a relevant carotid occlusion, values of less than 2.4 mm/sec2 were found in 100% of patients and only 4.5% of controls. Reactivity to breath holding promises to be a useful test in the evaluation of symptomatic patients with extra cranial carotid artery disease.

Aged↗
PubMed1989

Laser angioplasty with a pulsed NdYAG laser: early clinical experience.

Since December 1986, 40 laser angioplasty procedures have been performed using the energy from a pulsed NdYAG laser, delivering near infrared light (1064 nm) in 100-microseconds pulses of approximately 300 mJ per pulse, directly through a transparent sapphire tipped device. All patients had total occlusion of the superficial femoral artery and symptoms severe enough to warrant surgery, with ulceration or gangrene in eight, rest pain in 14 and severe claudication interfering with life-style in the others. The device was introduced through an antegrade puncture of the superficial or common femoral artery and laser recanalization was followed by attempted balloon angioplasty in all cases. Occlusions were a median length of 15 cm (range 2-35 cm); ten patients had previously undergone failed attempts at conventional balloon angioplasty and four had occluded femoropopliteal grafts. Thirty-seven legs of 34 patients were treated with an average of 60 J (range 10-235 J) with successful recanalization in 27 and immediate reocclusion in seven. The 20 successful recanalizations have been followed up for up to 24 months (median 7 months) with only one late occlusion at 5 months. Failed recanalization was due to poor transmission by the delivery device in the early part of the series (five cases), repeated passage of the device down a collateral branch (four cases), dissection at the site of previous surgery (two cases) or no apparent reason (two cases). Immediate reocclusion was due to very poor run off in patients with severely ischaemic limbs (three cases) or technical difficulties with balloon dilatation (two cases). Complete symptomatic relief was obtained in all the cases of radiologically successful laser angioplasty. Early surgery was required in one case following reocclusion of the artery when an angioplasty balloon failed to deflate, and one patient suffered a skin reaction thought to be due to inadequate removal of the sterilizing solution. A different sterilizing procedure is now followed. Laser angioplasty can reduce the number of patients requiring bypass surgery and improvements in the device and access methods may reduce the number of untreatable cases.

Adult↗
PubMed1989

Assessment of a new device for laser angioplasty.

Experimental work has shown that a transparent laser device delivering pulsed energy to an artery results in a smaller area of surrounding damage than does an opaque device with a continuous wave laser. The combination of a transparent ball-tipped device with a pulsed Nd-YAG laser has been investigated. The system delivers pulses of 100 microseconds at a rate of 10 Hz and average energy of 0.5 J per pulse with an energy loss of 5-10% between the output at the laser rail and the fibre tip. The dose/response was measured and showed that on normal aorta under saline the device produces craters with a depth of 5 microns/J and 1.5 mm radius. There is a 100% increase in dose response with diseased aorta and a 50% increase when exposure is carried out under blood. The effect of a varying angle of incidence upon the arterial wall has been measured. Angulation of the device at 10 degrees from the perpendicular reduces the crater depth to 50%, as compared with a 50% reduction at 60 degrees using a bare fibre. As estimated with a thermal camera in air, the device heats up to a maximum of 50 degrees C during a 50 J exposure, compared to 110 degrees C after 5 J for the sapphire device. Artificial circulation experiments were carried out using diseased femoral vessels occluded by a ligature. The new system recanalised 100% of occlusion in straight vessels, and 40% of occlusions in curved vessels at a radius of 2.5 cm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Resection of the extra cranial carotid artery in head and neck cancer.

Carotid artery resection and reconstruction by unreversed autogenous saphenous vein grafting was undertaken in six patients undergoing extensive resection for malignancy over a four-year period. There were two deaths within 30 days of operation: one from secondary hemorrhage and one from bronchopneumonia. One patient died at six months and one at three months from recurrence, one died at 12 months from recurrence and one died free of disease at 10 months from aspiration. Vascular complications in three patients included a single TIA at 14 days, graft thrombosis with hemiplegia and a secondary hemorrhage from the graft requiring graft ligature with a subsequent normal neurological status. Malignant involvement of the extracranial carotid artery is associated with poor survival. Treatment by carotid artery resection and grafting should be considered in such cases, particularly where the pharynx or oral cavity are not entered.

Aged↗
PubMed1987

Ankle blood pressure measured by automatic oscillotonometry: a comparison with Doppler pressure measurements.

Oscillotonometry using Dinamap machine was investigated for the measurement of ankle and brachial blood pressures in our vascular practice. It was validated by comparison with intra-arterial pressure measured by transducer. Systolic ankle and brachial pressures in 43 patients were compared using the Dinamap and Doppler techniques, and significant correlation was found. Ankle and brachial systolic, diastolic and mean pressures and ankle/brachial pressure indices for all three pressures were measured in a group of 12 normal subjects supine at rest, and after treadmill exercise, and a range of normal values defined. The main limitation of the Dinamap is its failure to measure pressures below 50mmHg. The Dinamap technique is a noninvasive, simple, reproducible and quick method of measuring ankle and brachial pressures in vascular surgical practice.

Adult↗
PubMed1984

Measurement of regional lower limb blood flow in normal humans by inhalation of 133Xe.

A non-invasive method of measuring regional calf blood flow after inhalation of 133Xe has been investigated. The mean blood flow at rest was 3.3 ml X min-1 X 100 g tissue-1 by the 133Xe method and 3.5 ml X min-1 X 100 g tissue-1 by plethysmography. There was a significant correlation r = 0.88, P less than 0.001. During exercise the mean blood flow in the anterior tibial compartment increased from 3.4 to 10.9 ml X min-1 X 100 g tissue-1 in ten cases and in the posterior compartment from 3.3 to 7.1 ml X min-1 X 100 g tissue-1 in seven cases as measured by the 133Xe technique. The inhalation method seems to be an accurate, reliable and non-invasive method for measuring tissue blood flow in the human calf at rest and during exercise.

Adult↗
PubMed1984

Measurement of skin and total blood flow to the rabbit lower limb by washout of freely diffusible radioactive tracers introduced intra-arterially.

Good agreement was obtained when measuring total (capillary) blood flow in 9 rabbit thighs using two different techniques. The 133Xenon washout technique yielded a mean value of 8.0 cm3 X min-1 X 100 g tissue-1 whilst the microsphere technique gave a mean value of 7.8 cm3 X min-1 X 100 g tissue-1. There was a significant correlation (r = 0.83, p less than 0.006). In a further 14 rabbit thighs an attempt was made to measure skin blood flow by washout of 85Kr and to compare it with the microsphere technique. 133Xe promises to be a useful tracer for measuring lower limb flow when introduced intra-arterially. Because 85Kr tends to underestimate skin blood flow, and because of problems of diffusion of the tracer between compartments, which are discussed, this tracer is not satisfactory as a technique for measuring skin blood flow.

Animals↗
PubMed1982

Clinical significance of recent inversion of the nipple: a reappraisal.

In a retrospective survey of 63 cases of inverted nipple, unaccompanied by a palpable mass, 3 histologically confirmed carcinomas were found on combined clinical and mammographic examination - an incidence of 5%. No carcinoma was found in those patients under 50 years of age. The problem of the false negative mammogram is discussed.

Adult↗
PubMed1982

Exteriorisation resection of the colon.

The early results of 34 exteriorisation resections of the colon are presented, 25 being emergency procedures and 9 elective. The operative mortality in the emergency group was 20% and there were no deaths in the elective group. All patients who survived the postoperative period have had their colostomies closed. The operation was technically simple and quick to perform. It is one of the safest methods of resecting colon. The technique proved to be a useful alternative to standard techniques in colonic perforation, colonic obstruction with proximal faecal retention, nonviable sigmoid volvulus, diverticular disease requiring resection, and colovesical and colouterine fistula.

Aged↗
PubMed1977

Aneurysms of the femoral artery.

Eight aneurysms of the femoral artery out of a total of 27 in 16 patients developed symptoms requiring surgery. The operation of choice was Dacron prosthetic replacement of the aneurysm with preservation of profunda femoris perfusion. The incidence of complications of aneurysms was 30 per cent. The asymptomatic aneurysms were untreated and did not cause the patients any inconvenience as observed at their follow-up. Hence, surgery is advocated only for patients who develop symptoms provided that adequate follow-up and community medicine facilities exist.

Adult↗
PubMed1976

The response of diastolic myocardial tissue pressure and regional coronary blood flow to increased preload from blood, colloid, crystalloid.

An increase in the left ventricular end-diastolic pressure (LVEDP), resulting from the intravenous administration of blood, a colloid solution, or a crystalloid solution, was accompanied by an increase in both the inner:outer left ventricular wall flow ratio and the diastolic myocardial tissue pressure gradient. With a normal left ventricular end-diastolic pressure, the normal inner:outer flow ratio was just above unity and the minimum diastolic myocardial tissue pressure in the subepicardium was twice as high as in the subendocardium. When the left ventricular end-diastolic pressure was raised, the subepicardial tissue pressure rose earlier and to a higher degree than the subendocardial; thus a gradient which encourages subendocardial flow was increased. This paper correlates the changes in diastolic myocardial tissue pressure and in inner:outer flow ratios which occurred when eight dogs were transfused with blood, seven with colloid, and seven with lactated Ringer's solution. Regional diastolic myocardial tissue pressure was measured by the flow-cessation technique and regional flow by radioactive microspheres. The gradient in diastolic myocardial tissue pressure, which is a major contributory factor to adequate subendocardial perfusion under normal conditions, is of even greater importance when LVEDP is raised.

Animals↗