Biomedical subjects
M D Clark
Publications and source records attributed to M D Clark.
Dissecting aneurysms of the aorta: roentgen manifestations including a comparison with other types of aneurysms.
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Carotid artery aneurysm diagnosed by duplex scanning.
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Drug use and nursing students. Part 1, A program for prevention.
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Drug use and nursing students: Part II. A program for prevention.
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Teacher response to learning disability: a test of attributional principles.
Attribution research has identified student ability and effort expended as causes of achievement outcomes that result in differing teacher affect, evaluative feedback, and expectation of future performance. Ninety-seven elementary-school general education teachers (84 women and 13 men) rated their responses to the test failures of hypothetical boys with and without learning disabilities. In most cases, greater reward and less punishment, less anger and more pity, and higher expectations of future failure followed the negative outcomes of the boys with learning disabilities, when compared with their nondisabled ability and effort matches, indicating that learning disability acts as a cause of achievement outcomes in the same way as ability and effort. This pattern of teacher affect and response can send negative messages that are often interpreted as low-ability cues, thus affecting students' self-esteem, sense of competence as learners, and motivation to achieve.
The nurse educator in an expanded consultant role.
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Nd:YAG iliac and femoropopliteal laser angioplasty: results with large probes as "sole therapy".
Laser assisted balloon angioplasty with a laser heated metallic capped fiberoptic catheter may be effective in the treatment of femoral and iliac artery occlusive disease. In order to avoid the inherent trauma of balloon angioplasty, yet at the same time "debulk" atheroma, 75 patients underwent laser angioplasty of the superficial femoral and iliac arteries as "sole therapy". Laser angioplasty was performed using an Nd:YAG laser coupled to a 600 micron fiber and a 3.5 mm probe (22-28 watts), 4.2 mm or 5.0 probe (32-40 watts). Fifty-nine patients had laser angioplasty for claudication and 16 for limb salvage. The initial angiographic success rate was 84% (41/49) (lesion length 2-14 cm) for the superficial femoral and 69% (18/26) (lesion length 2-14 cm) for the iliac arteries. In follow-up extending to 21 months (mean 14.4 months) 73% (30/41) of the superficial femoral artery and 76% (14/18) of the initially recanalized iliac arteries remain patent. When initial failures are included, this represents an overall intermediate-term patency rate of 52% (32/49) for superficial femoral and 49% (14/26) for iliac arteries respectively. By avoiding the disruptive effect on the arterial wall architecture caused by balloon angioplasty, while at the same time ablating and vaporizing more atheromatous material with larger laser probes, the long-term patency rates of laser angioplasty as "sole therapy" may prove to be superior to those of laser assisted balloon angioplasty.
Prosthetic above-knee femoropopliteal bypass for intermittent claudication.
There is no consensus about the most appropriate management of the patient with intermittent claudication due to a superficial femoral artery occlusion. To evaluate the natural history of prosthetic above-knee femoropopliteal (AKFP) bypass, 200 operations for intermittent claudication were reviewed. One hundred AKFP bypasses were done with PTFE and 100 with dacron. In the 30 day postoperative period, four PTFE and three dacron grafts occluded without consequence and only one patient died. Analysis of results by the life-table method demonstrated statistically similar primary graft patency rates at five years (PTFE 65% SE +/- 6.5, dacron 57% +/- 6.2) and ten years (PTFE 31% +/- 18/9, dacron 32% +/- 13.2) (p greater than 0.10). Redo procedures (e.g., thrombectomy, angioplasty) were necessary on 21 grafts (12 PTFE, 9 dacron) and "secondary" patency rates at five years were 76% PTFE and 62% dacron; no grafts which required a redo procedure were patent at ten year follow-up. Major amputations during ten year follow-up were necessary in 16 (8%) patients; all amputations were in diabetic patients. Survival rates were 79% at five and 42% at ten years. An anticipated, the leading cause of death was cardiac related (25 patients); 28 (14%) patients underwent aortocoronary bypass during follow-up. A prosthetic AKFP bypass graft is a safe and durable operation which provides relief from the symptoms of intermittent claudication while allowing for the preservation of the saphenous vein for use later in the coronary or infrapopliteal circulations, should the need arise. These results indicate that the risk of amputation after AKFP is no greater than the natural history of untreated claudication; however, AKFP offers a significant improvement in life-style.
Axilloaxillary bypass: is it worthwhile?
To evaluate the efficacy and long-term patency results of axilloaxillary bypass, a review of 32 patients with follow-up extending to 11 years was done. Twenty-two bypasses were performed for vertebrobasilar symptoms or subclavian steal and 10 for upper extremity claudication and/or ischemia. The mean age of the operative group was 66 years, 94% of patients had more than one atherosclerotic risk factor (hypertension, diabetes, coronary artery disease, smoking), and 75% had undergone a previous arterial reconstruction operation. There were no operative deaths, and the only postoperative complication was a sterile seroma which responded to aspiration. At late follow-up extending to 11 years, three grafts had thrombosed while another became infected and had to be removed; no limb loss resulted from these graft failures and the actual late patency rate was 87%. Carotid-subclavian bypass, intrathoracic bypasses, and endarterectomy at the site of occlusion have all been suggested for the treatment of symptomatic proximal subclavian artery disease. With axilloaxillary bypass, however, the hazards associated with carotid artery manipulation, operation on the notoriously treacherous subclavian artery, and the morbidity related to thoracotomy in this older, high-risk patient population can be avoided. The axilloaxillary bypass is safe and simple, and the excellent long-term patency rates make it the procedure of choice for symptomatic subclavian artery disease.
"Chronic-contained" ruptured abdominal aortic aneurysm: is it real?
Rupture of an abdominal aortic aneurysm is readily diagnosed when the triad of abdominal or back pain, shock and a pulsatile abdominal mass are present. Clinical diagnosis can be difficult, however, when patients present with chronic pain and an aneurysm which is not readily palpable. In these patients with confusing abdominal symptoms, CT scan provides a rapid, noninvasive diagnosis. The acute leaking AAA has been documented, but only rarely. This report identifies two patients who ruptured an aortic aneurysm several "months" prior to operation--a "contained chronic" rupture.
Carl Rogers revisited.
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