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Biomedical subjects

R J Lusby

Publications and source records attributed to R J Lusby.

At least 37 records · Page 2Linked to original sources
PubMed1983

Carotid plaque histology using real-time ultrasonography. Clinical and therapeutic implications.

To evaluate the ability of ultrasonographic imaging to detect plaque hemorrhage in carotid atheroma, a study was undertaken that compared pathologic findings to preoperative ultrasonographic findings. Ultrasonography identified two plaque categories based on the heterogeneous and homogeneous echo patterns of the lesions studied. Heterogeneous lesions accounted for 91 percent of intraplaque hemorrhages (30 of 33) and 100 percent of ulcerated lesions (15 of 15). In 41 of 50 specimens (82 percent), ultrasonography correctly identified the presence or absence of plaque hemorrhage. False-negative studies (3 of 50) were due to the minute foci of remote hemorrhages. False-positive studies (6 of 50) resulted from plaques that contained large amounts of lipid or cholesterol. Preoperative ultrasound carotid imaging can be used to detect the histologic characteristics of plaque. Since recent clinicopathologic studies have implicated intraplaque hemorrhage and ulceration in symptomatic carotid disease, this information may be of value in choosing therapy, especially for the asymptomatic patient.

Aged↗
PubMed1983

Vessel wall and indium-111-labelled platelet response to carotid endarterectomy.

Postendarterectomy platelet deposition and thrombus formation may play an important role not only in vessel wall healing but also in the small incidence of postoperative cerebral ischemia and postoperative stenosis. A study has been performed using a canine model to investigate the healing response to carotid endarterectomy and the validity of an in vivo indium-111 (In-111) radiotracer technique in the assessment of postendarterectomy deposition of autologous labelled platelets. Sixteen endarterectomized carotid arteries showed uptake of autologous In-111 platelets immediately after infusion, reaching a maximum by 1 hour with little increase at 24 or 48 hours. No uptake was seen in ten control vessels following platelet infusion (P less than 0.05). At autopsy, seven vessels were demonstrated to have In-111 platelet deposition immediately prior to sacrifice of the animals. Postmortem scanning confirmed the localization to the vessel lumens, and microscopy revealed thrombus formation with or without partial endothelialization. Complete reendothelialization had occurred in the vessels that failed to show platelet deposition. Delayed healing was associated with continuing platelet deposition, excessive thrombus formation, and luminal stenosis. Arteriotomy closure with a vein patch altered the healing characteristics of the vessel with segmental thrombus formation over the vein patch. A preliminary study of the postendarterectomy in vivo In-111 platelet response in humans demonstrated platelet deposition that was not influenced by the administration of antiplatelet drugs at currently prescribed levels.

Animals↗
PubMed1982

Carotid plaque hemorrhage. Its role in production of cerebral ischemia.

A prospective study of carotid endarterectomy specimens showed an acute or recent intraplaque hemorrhage in 49 of 53 plaques (92.5%) from symptomatic patients, compared with seven of 26 plaques (27%) from nonsymptomatic patients. Luminal stenosis of greater than 50% was noted in 46 of 53 symptomatic patients (75%), 43 of whose plaques had evidence of multiple hemorrhages. Intimal disruption (ulceration) occurred over protruding mounds of intraplaque hemorrhage and was associated with retinal cholesterol emboli and prolonged neurologic deficits. Mural recesses with the angiographic appearance of ulceration seldom showed intimal breakdown. Eighteen patients continued to have symptoms while receiving aspirin, 13 of whom had had multiple intraplaque hemorrhages. Angioneogenesis occurred within the plaques in response to hemorrhage, creating vascular lesions vulnerable to mechanical stress and capable of producing further hemorrhage or intimal disruption.

Animals↗
PubMed1982

Management of retained cystic duct stones.

A 20-year-old woman underwent cholecystectomy and common bile duct exploration. Seven days later, T-tube cholangiography showed two stones retained in a developmentally anomalous cystic duct stump. She was treated with thrice-daily flushings of large amounts of saline through the T tube, and after 7 days of treatment the biliary system was free of stones. The conditions necessary for successful non-operative management of retained cystic duct stones are discussed.

Cholelithiasis↗
PubMed1982

Transient ischaemic attacks: the static and dynamic morphology of the carotid artery bifurcation.

Studies evaluating the static and dynamic characteristics of the common carotid bifurcation are described. Slow motion angiographic frames, real time B-mode images and time position M-mode tracings have demonstrated appreciable vessel wall motion with an increase in distensibility at the carotid bulb compared to the proximal common carotid artery. Histopathological studies suggest that changes in the carotid artery elastin and collagen structure may contribute to the increased distensibility at the carotid bulb. The presence or absence of a cervical bruit did not correlate with the ultrasonic demonstration of plaque or blood flow turbulence. Mechanical factors relating to the development of symptoms of cerebral ischaemia are discussed.

Auscultation↗
PubMed1982

Carotid artery surgery based on digital subtraction angiography.

This study shows that digital subtraction angiography provides the morphologic criteria necessary for surgical intervention in most patients with carotid atheroma. Digital subtraction angiography provides a safe means of studying patients, with an overall sensitivity of 96 percent and specificity of 86 percent. Radiopaque casts of the operative specimen have been used as the gold standard, providing a suitable means of comparing the findings on digital subtraction angiography with the operative findings. Failure to obtain visualization of the vessels with biplanar views required conventional angiography to properly evaluate the vessels in 12 percent of patients. This technique represents a major advance in the study of carotid artery disease which may replace many of the current imaging techniques.

Arteriosclerosis↗
PubMed1982

Infrapopliteal bypass grafting: use of upper limb vein alone and in autogenous composite grafts.

Thirty-seven consecutive vein grafts to the infrapopliteal arteries are reviewed. Upper limb vein was used in each case, either for the entire graft (27%) or in combination with saphenous vein (73%). The grafts were inserted during a 10-year period and constituted 8.6% of the lower limb grafts carried out during this time. There was one postoperative death (2.7%). The patency rate at 3 years was 58 +/- 9.5% and at 5 years 49.1 +/- 11.5%. Indications for the use of upper limb vein in these situations are considered, and the results are compared with those obtainable with other materials. Upper limb vein can provide a satisfactory arterial substitute in the lower limb, and it may occasionally be the material of choice.

Aged↗
PubMed1981

Department of Surgery, Bristol Royal Infirmary, U.K.

Recent developments in ultrasound techniques have made it possible to investigate patients with arterial disease non-invasively by using Doppler blood velocity signal analysis. Since January 1979, 189 patients were pre-stroke syndromes have been investigated by using pulsed Doppler and real-time B-mode ultrasound imaging and waveform analysis. The results were that both imaging systems were highly (more than 92%) sensitive and specific when compared with conventional carotid arteriography. The ultrasound systems detected turbulence and could also be used to measure the distensibility of the arterial wall. The results show that varying grades of carotid stenosis can be demonstrated by two ultrasonic imaging systems, and that lateral scans are particularly helpful.

Blood Flow Velocity↗
PubMed1981

Cigarette smoking: acute main and small vessel hemodynamic responses in patients with arterial disease.

While cigarette smoking is a major risk factor in lower limb ischemia, not all smokers develop symptomatic lesions, which suggests an individual susceptibility. Using Doppler probes the acute main vessel response to smoking was quantified in terms of the pulse transit time delay. Patients with occlusive arterial disease had a significant shortening in the transit time delay, suggesting a stiffening in the main vessels in response to smoking not seen in control subjects without disease. In patients with occlusive disease the digital pulse volume recorder amplitude decreased significantly in response to both low and high nicotine cigarettes, and these patients tended to self-titrate their nicotine intake, suggesting that little is to be gained by switching from high to low nicotine cigarettes: rather, cessation of smoking should be considered. These preliminary results suggest that patients with atherosclerotic occlusive disease are more susceptible to cigarette smoking and that Doppler or pulse volume recorder testing may help identify those habitual smokers who are at risk.

Adolescent↗
PubMed1980

Upstream stenosis. Its diagnosis by Doppler signals from the femoral artery.

Transcutaneous femoral artery Doppler signals were measured with a 10-MHz pencil probe in 263 lower limbs of 135 patients. The Doppler waveforms were compared with arteriograms in 125 limbs with lower-limb ischemia and in 138 controls in the detection of minor (< 50%) and major (> 50%) iliac-artery stenosis. Doppler maximum velocity-time waveforms were obtained using a maximum frequency follower, and the wave-form shape was analyzed using a Laplace transform (LT) to produce a coefficient, the LT damping. Pulsatility index (PI) was also calculated. In 62 limbs with minor artery disease, mean LT damping was significantly greater than normal (0.5 +/- 0.15 vs 0.33 +/- 0.06; P < .001). In 63 limbs with major iliac stenosis, mean LT damping was higher still (0.78 +/- 0.16; P < .02). The LT damping was not affected by increased distal impedance and there was a good correlation with iliac stenosis in 65 limbs with an occluded superficial femoral artery (r = -0.73). The results with PI were inferior at every grade of severity of iliac disease when assessed by receiver-operator characteristic curves. These results suggest that LT damping is a sensitive method of analyzing femoral Doppler signals in the noninvasive detection of iliac artery stenosis.

Arterial Occlusive Diseases↗
PubMed1979

Antral patch esophagoplasty. A new procedure for acid-peptic esophageal stricture.

Antral patch esophagoplasty is a new procedure for intractable fibrous stricture of the esophagus secondary to acid-peptic reflux. A full-thickness patch of gastric antrum, supplied by a pedicle based on the left gastroepiploic vessels, is inserted, mucosal surface to lumen, into the opened stricture. A fundoplication is done below the esophagoplasty to prevent reflux. The functional results were excellent in five of six patients. The procedure may have application also in other types of benign esophageal stricture.

Aged↗
PubMed1979

Gastric patch esophagoplasty: an experimental study.

To determine whether the use of pedicled full-thickness gastric patches would be feasible and safe in esophageal reconstruction, studies were undertaken in eleven dogs. The results demonstrate that patches containing parietal cell mucosa are likely to produce localized adjacent esophagitis. Patches containing antral mucosa do not produce esophagitis and are not associated with a subsequent increase in circulating serum gastrin levels.

Animals↗
PubMed1979

Pulsed Doppler angiography in lower limb arterial ischemia.

A 30-channel pulsed Doppler vessel imaging system (MAVIS, GEC Medical, Middlesex, England), was used to obtain images and maximal Doppler velocity time waveforms in the diagnosis of stenosis of the origin of the profunda femoris artery (PFA) and in the detection of structural changes within Dacron arterial grafts. In PFA scans of 33 limbs in 22 patients (mean age, 52 years), PFA stenosis of more than 50% at operation was invariably associated with a damping factor of the maximal Doppler velocity-time waveform of greater than 1.5 (eight limbs). In 12 limbs with a normal PFA at operation, the damping factor was always less than 1.4, and in 13 limbs of normal patients without arterial disease, the damping factor was always less than 1.34. In studies of 10 mm arterial grafts, the internal diameter of 14 iliopopliteal grafts scanned just above the popliteal anastomosis was strikingly reduced as compared with the femoral anastomosis of 14 aortoiliofemoral grafts and seven axillobifemoral grafts. These preliminary results suggest that MAVIS studies can be used noninvasively to detect PFA stenosis and to identify luminal narrowing of iliopopliteal grafts.

Angiography↗
PubMed1977

Postoperative recurrent peptic ulcer: the significance of the Zollinger-Ellison syndrome.

Twenty-four patients with postoperative recurrent peptic ulcer, presenting to a teaching hospital over a six-year period, are reviewed. The diagnosis was confirmed by endoscopy or surgery in all cases. Four patients (16-7%) were shown to have the Zollinger-Ellison syndrome and were treated successfully by total gastrectomy. This is a significantly higher incidence of Zollinger-Ellison syndrome than in previous reports. Six patients were treated medically, with one death. In the remainder, an inadequate initial operation was considered to be the cause of recurrence. Reoperation, usually involving complete vagotomy and antrectomy, was performed. There was no mortality in this group, and no patients have had further recurrence. The importance of serum gastrin studies in all patients with recurrent peptic ulcer is emphasized.

Female↗
PubMedDate not supplied

The Australian Medical Support Force in Rwanda.

In the aftermath of the Rwandan civil war, Australia's defence forces deployed a medical force to support the United Nations Assistance Mission. In this article, Wayne Ramsey, Commander of the Australian contingent, Lindsay R Bridgford, Officer Commanding Bravo Section, Robert J Lusby, Lt.-Colonel (Surgeon), Australian Medical Support Force Hospital, and John H Pearn, Colonel, and Director of Intensive Care in the Australian Medical Support Force Hospital, describe the Australian effort in the rebuilding of a shattered people and, in particular, of Kigali Central Hospital, the country's major medical facility.

Adult↗