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Biomedical subjects

C J White

Publications and source records attributed to C J White.

At least 109 records · Page 6Linked to original sources
PubMed1991

Percutaneous coronary angioscopy in patients with restenosis after coronary angioplasty.

Percutaneous transluminal coronary angioscopy with a flexible steerable microangioscope was performed in five patients undergoing repeat angioplasty. Recurrent lesions were assessed by angioscopy before and after the angioplasty procedure. The most common surface morphology observed in these restenosis lesions was that of white unpigmented lesions consistent with the proliferation of fibrous tissue. Also noted during angioscopy was the presence or absence of thrombus or dissection in association with the lesions either before or after angioplasty. Filmy wisps of tissue, presumably intimal flaps, were commonly visualized after angioplasty. There were no complications related to angioscopy or angioplasty in these patients. The surface morphology of restenosis lesions appears to be different from that of primary atherosclerotic lesions. The lesions in these five patients with restenosis were generally white and fibrotic in appearance, as opposed to the pigmented yellow to yellow-brown lesions commonly seen in undilated atherosclerotic lesions. It was also noted that the presence of intracoronary thrombus was strongly associated with the clinical syndrome of unstable angina. These findings support the hypothesis that restenosis lesions are the result of a reparative process consisting of smooth muscle cell proliferation and fibrosis.

Adult↗
PubMed1991

New directions in percutaneous intervention for peripheral vascular disease.

Balloon angioplasty is a safe and effective alternative to surgical reconstruction or bypass in selected patients with symptomatic iliofemoral and popliteal atherosclerosis. The current literature suggests an expanding role for balloon angioplasty in patients with symptomatic tibioperoneal disease as well as upper extremity claudication and subclavian steal syndrome. Newer percutaneous devices such as atherectomy, intravascular stents, and laser angioplasty may further broaden the indications for percutaneous intervention by improving their safety and long-term benefit. The latest advances in percutaneous intervention for peripheral vascular disease are reviewed.

Angioplasty, Balloon, Coronary↗
PubMed1991

Laser angioplasty in miniature swine: advantages of a modified fiber tip delivery system.

Laser angioplasty using a spherical lensed fiber-tip laser delivery catheter and a 200 mum bare silica fiber tip was performed in occluded atherosclerotic iliac arteries of miniature swine. Group I consisted of 8 animals with 11 totally occluded arteries in which the bare silica fiber was used. Group II included 22 animals with occlusive lesions in 41 arteries in which the silica lens tip was used. In vivo laser angioplasty was performed in both groups using an argon ion laser delivering 2 to 3 watts of power in 1 to 5 second intervals. Successful recanalization occurred in 7/11 (64%) in group I arteries and 35/41 (85%) in group II arteries. Vascular perforation occurred in 36% (4/11) in group I compared to 10% (4/41) in group II (P less than 0.05). Mechanical perforation due to the bare fiber alone accounted for 50% of the perforations in group I and did not occur with the silica lens-tip device (group II). We conclude that the atraumatic lensed fiber is more effective in recanalizing occlusive lesions and is a safer delivery system than the bare silica fiber.

Angioplasty, Laser↗
PubMed1991

Varicella vaccine (VARIVAX) in healthy children and adolescents: results from clinical trials, 1987 to 1989.

A total of 3303 healthy children and adolescents, aged 12 months to 17 years, were vaccinated with one of five production lots of a live attenuated varicella vaccine (VARIVAX) containing 1000 to 1625 plaque-forming units per dose. The vaccine was generally well tolerated. Ninety-six percent (2381/2475) of vaccinees responded to vaccination by producing antibody as measured by a glycoprotein-based enzyme-linked immunosorbent assay; 99% (569/576) of those tested maintained antibody at 1 year following vaccination. The incidence of varicella following household exposure in vaccinees was approximately 12%; household contact historically results in 87% infection. Nearly all of the vaccinees who had varicella after vaccination had a clinically modified disease.

Adolescent↗
PubMed1990

New passive perfusion PTCA catheter.

Percutaneous coronary angioplasty with a new passive perfusion balloon catheter was compared to a standard angioplasty balloon catheter during prolonged balloon inflations in miniature swine. Inflations with the passive perfusion balloon were alternated with a standard balloon with the initial balloon chosen randomly in 24 coronary arteries. End-points for terminating the balloon inflation were the appearance of 2 mm of ST segment deviation from baseline on the electrocardiogram, the occurrence of ventricular fibrillation, or 30 min of balloon inflation. During balloon inflation contrast injections were performed through the guiding catheter and flow distal to the balloon was graded 0-3 using the TIMI scale. The average (+/- SD) inflation time for the standard balloon was 3.1 +/- 2.2 minutes and for the perfusion balloon was 27.2 +/- 4.8 min (P less than 0.001). Electrocardiographic evidence of 2 mm of ST segment deviation from baseline was seen during 11/13 inflations with the standard balloon and in 3/11 balloon inflations with the perfusion balloon. Ventricular fibrillation occurred during 2/13 of the standard balloon inflations and in none during passive balloon inflations. Distal contrast flow during passive balloon inflations averaged 2.7 +/- 0.5 (TIMI scale 0-3) and was absent during inflations with the standard balloon. The perfusion balloon allowed prolonged inflations with excellent distal flow when compared to the standard balloon.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1990

Use of a guiding catheter for contralateral femoral artery angioplasty.

We describe a unique method employing a transseptal sheath as a "guiding catheter" that allows contralateral retrograde femoral artery access to perform balloon angioplasty of proximal superficial femoral artery lesions. This technique simplifies arterial access, provides support for crossing lesions, and allows angiographic visualization of target lesions during the procedure.

Aged↗
PubMed1990

Percutaneous coronary angioscopy: methods, findings, and therapeutic implications.

The development and clinical implementation of percutaneous coronary angioscopy represents an engineering triumph, blending the newest technologies and materials in the field of fiberoptics with the most advanced techniques of balloon angioplasty catheter materials and construction. Current devices provide a safe method for acquiring excellent quality images of the coronary arteries. This is due to major advances in catheter alignment techniques allowing coaxial positioning of the angioscope in the relatively tortuous coronary arteries. Additional development is needed to further refine the degree of operator control over the field of view, which would also reduce procedure duration. The percutaneous coronary angioscope is currently a functional device for investigators attempting to correlate the morphology of atherosclerotic lesions and clinical coronary artery disease. Confirmation of the value of the angioscope as a clinically useful device for routine application in the diagnosis and management of cardiovascular disease will depend upon the results of further studies.

Angioplasty, Balloon, Coronary↗
PubMed1990

Myocardial ischemia caused by postoperative malfunction of a patent internal mammary coronary arterial graft.

The internal mammary artery is used with increasing frequency for myocardial revascularization. However, preoperative coronary angiography does not always provide adequate visualization of subclavian arteries. If a proximal subclavian artery stenosis exists or develops in a patient who has myocardial revascularization with the internal mammary artery, graft malfunction can occur resulting in myocardial ischemia. We have identified four cases of internal mammary artery graft malfunction at our own institution and identified an additional 12 cases from the literature. These 16 cases are analyzed for age, sex, time of onset of symptoms, clinical findings, method of revascularization, and long-term follow-up. Sixty-three percent of the patients were men, and the mean age was 52.9 +/- 9.0 years. Onset of symptoms occurred after a mean interval of 25.1 months from the time of myocardial revascularization. Three patients had asymptomatic reversal of flow in the internal mammary artery as diagnosed by coronary arteriography during routine follow-up examination before 1980. One death after internal mammary artery-coronary bypass grafting was related to immediate malfunction. In the remaining 12 patients with symptomatic malfunction, all but one were treated by placement of a carotid-subclavian bypass graft with no mortality. Relief of myocardial ischemia was complete in 93% of the patients with a mean follow-up of 29.3 months. Carotid-subclavian bypass grafting appears to be the treatment of choice for the usual management of internal mammary artery graft dysfunction. Careful preoperative evaluation and postoperative follow-up of the subclavian arteries, even by simple comparison of bilateral arm blood pressure should help reduce the incidence of this syndrome.

Blood Vessel Prosthesis↗
PubMed1990

Laser angioplasty in coronary artery disease.

At the present time all laser coronary angioplasty systems in use are investigational devices awaiting FDA approval. Preliminary results in human trials of several coronary laser angioplasty systems have been reported and appear encouraging. The technological achievement of delivering laser energy to the coronary circulation and opening occluded arteries has been accomplished. The much more difficult question of determining which patients, if any, should be offered this very expensive technology remains to be answered.

Coronary Disease↗
PubMed1989

Repeat balloon aortic valvuloplasty for aortic valve restenosis.

Effective balloon aortic valvuloplasty (BAV) is limited restenosis. After aortic valve restenosis six patients underwent repeat BAV. In spite of the use of larger balloons there was a trend toward a less satisfactory result after repeat BAV (0.98 +/- .26 cm2 vs. 1.2 +/- .26 cm2), which did not reach statistical significance, P = .14. Mortality of the patients at 6 months was 50%. Repeat BAV may be less efficacious than the original procedure.

Aged↗
PubMed1988

Laser angioplasty: an atherosclerotic swine model.

Rapid production of occlusive, atherosclerotic iliac artery lesions was achieved in 25 of 27 (93%) Yucatan miniature swine, using a combination of high cholesterol diet and mechanical endothelial denudation. Animals were fed a diet with 2% of their calories as raw cholesterol 2 weeks prior to balloon denudation of iliac arteries, which resulted in atherosclerotic lesions within 8 weeks. Early after denudation we have demonstrated total occlusion of arteries by fibrin thrombi, which in time organize and ultimately result in fibrotic occlusive disease. The arterial walls and intima show varying degrees of foam cell infiltration with destruction of the internal elastic lamina and calcification. Totally occluded lesions show fibrointimal proliferation, fibrosis, and multiluminal channels, which are probably secondary to organized thrombus. Our model of occlusive iliac artery disease involving vessels of 1 to 3 mm in diameter allows the development of catheter systems suitable for use in human peripheral and coronary arteries. This model is useful for the study of angioplasty, whether mechanical, balloon, or laser-mediated.

Angioplasty, Balloon↗
PubMed1988

Collagen gel culture of rat mammary tumor cells as an assay system for determination of therapeutic efficacy of chemotherapeutic agents.

Collagen gel culture of rat mammary epithelial cells was used as an in vitro assay system for determination of the therapeutic efficacy of three cytotoxic agents commonly used in the treatment of human breast cancer, namely 5-fluorouracil (5-FU), methotrexate, and Adriamyin (ADR). The same three drugs were also evaluated in vivo, and a good correlation was obtained between the results in these two systems. A 9-d culture was shown to be more reliable than a 12-d culture, because nondrug-related cell mortality became a confounding factor after 12 d. Although further experiments are necessary, it is suggested that collagen gel culture may well prove to be a useful assay system for determination of sensitivity of tumor cells to cytotoxic drugs with possible clinical applications in the choice of treatment modality administered to cancer patients.

Animals↗
PubMed1988

Cryptococcosis of the colon resembling Crohn's disease in a patient with the hyperimmunoglobulinemia E-recurrent infection (Job's) syndrome.

A 29-yr-old woman presenting with granulomatous colitis and a chronic perirectal abscess was found to have localized cryptococcosis associated with the hyperimmunoglobulinemia E-recurrent infection (Job's) syndrome. Similarity to previous cases of esophageal cryptococcosis and ileocecal histoplasmosis suggests an association between the hyperimmunoglobulinemia E-recurrent infection syndrome and localized fungal infections of the alimentary tract. To our knowledge, this is the first well-documented case of cryptococcosis confined to the colon and perirectal tissues.

Adult↗
PubMed1988

Coronary artery disease in aortic surgery.

The incidence of coronary artery disease in patients coming to aortic surgery and the impact of aggressive preoperative cardiac catheterization and myocardial revascularization was prospectively analyzed in 59 patients. Seventy-five percent of patients had at least one-vessel involvement, and 32% had three-vessel or left main involvement. Patients with electrocardiographic evidence of coronary artery disease had at least one-vessel involvement 84% of the time and three-vessel, left main involvement 36% of the time. Sixty-four percent of patients with no preoperative indications of coronary artery disease had at least one-vessel involvement and 29% had three-vessel, left main involvement. Resting (39 patients) and exercise multiple-gated acquisition scans (22 patients) did not predict the presence of coronary artery disease in patients without a history or electrocardiographic evidence of coronary artery disease. Myocardial revascularization was performed prior to aortic surgery in 17 patients (29%). The operative mortality was 3.7% with two patients dying from noncardiac-related complications. There were two additional deaths prior to aortic surgery with one patient dying during coronary artery bypass grafting, and one dying of aneurysm rupture prior to repair, making the overall mortality associated with this approach 7.4%. Preoperative cardiac catheterization and an aggressive approach toward coronary artery bypass grafting reduces the risk of cardiac complications in aortic surgery.

Aged↗
PubMed1988

Recombinant human interferon-gamma reconstitutes defective phagocyte function in patients with chronic granulomatous disease of childhood.

Monocytes from 19 of 30 patients with the classic phenotype of chronic granulomatous disease of childhood (CGD) responded to 3 days of treatment in culture with recombinant human interferon-gamma (rHuIFN-gamma) at 100 units/ml by producing superoxide after stimulation with phorbol 12-myristate 13-acetate. Cells from 15 of 16 patients with cytochrome b-positive CGD (15 with autosomal and 1 with X chromosome-linked inheritance) and cells from 4 of 14 patients with cytochrome b-negative CGD (13 with X chromosome-linked and 1 with autosomal recessive inheritance) responded. Subcutaneous rHuIFN-gamma (0.01-0.05 mg/m2) administered as a single dose, daily or every other day, for five or six doses to 3 patients whose phagocytes responded to rHuIFN-gamma in vitro resulted in significant improvement in phagocyte bactericidal activity against Staphylococcus aureus and increases in superoxide production. Studies on 1 patient's cells indicated the increases in superoxide production correlated with increased membrane cytochrome b. The effects of rHuIFN-gamma persisted for more than a week following cessation of therapy. Thus, we have demonstrated a partial correction in vivo of these CGD patients' phagocyte defect with rHuIFN-gamma. Moreover, the data suggest that a significant proportion of patients with CGD will respond to rHuIFN-gamma with augmentation of phagocyte microbicidal function.

Blood Bactericidal Activity↗