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Biomedical subjects

R Bower

Publications and source records attributed to R Bower.

At least 19 recordsLinked to original sources
PubMed1995

Preventing intimal hyperplasia with photodynamic therapy using an intravascular probe.

The purpose of this study was to determine the efficacy of intravascular photodynamic therapy (PDT) to prevent the development of intimal hyperplasia. Anesthetized New Zealand white rabbits underwent placement of Fogarty balloon catheters introduced via femoral artery cutdowns. Catheters were passed retrograde 10 cm into the lower abdominal aorta, inflated six times, and withdrawn toward the inguinal ligament. Rabbits were then randomly assigned to one of the following groups: group 1, drug with no light; group 2, no drug with 240 joules of light; group 3, drug plus 120 joules of light; or group 4, drug plus 240 joules of light. Uninjured carotid arteries served as negative control vessels (N) and injured but non-PDT-treated iliac artery segments served as positive controls (P). Porfimer sodium (photofrin) was administered in a dose of 5.0 mg/kg. Light was provided by a fiberoptic probe with a 1 cm cylindric diffuser attached to an argon pumped dye laser tuned to 630 nm to provide 1 W of laser light for 120 or 240 seconds. One month after PDT, rabbits were killed, perfusion fixed with glutaraldehyde, and vessels removed and examined microscopically. Intimal thickness (mean +/- SD) was calculated and expressed as ratios of the intima/media at four equal positions. Results for N, P, and groups 1, 2, 3, and 4 were 0.02 +/- 0.00, 1.18 +/- 0.71, 0.76 +/- 0.33, 0.96 +/- 0.43, 0.14 +/- 0.22, and 0.36 +/- 0.16, respectively. Intimal thickness was significantly reduced in groups 3 and 4 when compared with P, group 1, and group 2 (p < 0.001, ANOVA). These results showed that intravascular PDT was effective in reducing intimal hyperplasia following arterial injury. This may be a practical method of delivering light for PDT.

Animals↗
PubMed1993

Effects of promoter, intron and enhancer elements on transient gene expression in sugar-cane and carrot protoplasts.

Various chimaeric promoter regions coupled to the uidA beta-glucuronidase gene were evaluated for transient expression strength following electroporation into sugar-cane (monocot) and carrot (dicot) protoplasts. Multiple enhancer elements increased expression in sugar-cane, by up to 400-fold for the artificial Emu promoter relative to the CaMV 35S promoter. The relative expression strengths of promoters varied substantially between the species. Sugar-cane also differed in some respects from previously tested species in the family Poaceae. For example, in sugar-cane the nopaline synthase and CaMV 35S promoters were of equivalent strength, and insertion of Adh1 intron 1 into the 5' transcribed region decreased expression strength.

Enhancer Elements, Genetic↗
PubMed1989

Immunohistologic analysis of the inflammatory infiltrates associated with osseointegrated implants.

A panel of monoclonal antibodies was used in an avidinbiotin immunoperoxidase technique to provide an immunohistologic analysis of the inflammatory infiltrates in the gingiva of osseointegrated implants. A total of 27 gingival and 13 interimplant specimens was obtained from 13 patients. Eighteen of the gingival specimens were clinically healthy, while nine showed overt signs of clinical inflammation (GI = 2 or 3). All specimens showed some degree of inflammation histologically, although the size of the inflammatory infiltrate was much greater in the clinically inflamed specimens. There was no significant difference in the proportion of T (50% to 60%) or B (40% to 50%) lymphocytes in either group. The CD4:CD8 ratio also showed no significant difference: 1.6:1 in the healthy group and 2.0 in the inflamed group. Similar ratios were also found in the infiltrates of the interimplant tissue. The immunohistologic analysis suggests that the gingival lesion associated with these implants is a stable, well-controlled response.

Antibodies, Monoclonal↗
PubMed1985

Electrophysiologic testing in patients with recurrent syncope: are results predicted by prior ambulatory monitoring?

Syncope is a common medical problem which can result from many etiologies, including cardiac dysrhythmias. Because ambulatory monitoring usually fails to capture a syncopal episode, electrophysiologic testing has been used to elucidate dysrhythmic mechanisms in patients with recurrent syncope. To assess whether findings on ambulatory monitoring not obtained during syncope can be used to indicate the results which are found on electrophysiologic testing in patients with recurrent syncope, we reviewed the ambulatory monitoring records of 59 such patients referred for electrophysiologic testing. Although 29 patients had abnormalities on electrophysiologic testing, 13 of which were severe, in only six were the findings suggested by the abnormalities recorded during ambulatory monitoring. Twenty-one patients actually had concordance between electrophysiologic testing and ambulatory monitoring results, but in 15 of the 21 results of both tests were normal. Severe abnormalities were more frequently detected in our patient population by electrophysiologic testing than by ambulatory monitoring, especially if patients had organic heart disease.

Adolescent↗
PubMed1980

Haemodynamics of stable renal transplant recipients.

1. Haemodynamics, blood volume, plasma renin concentration and creatinine clearance were evaluated in 24 stable renal transplant recipients. 2. The mean cardiac index of the transplant recipients was not different from that of the normal subjects. 3. The transplant recipients comprised eight hypertensive and 16 normotensive patients. The mean cardiac index was the same in eight hypertensive and 16 normotensive patients. Thus the hypertension of stable renal transplant recipients is sustained by a high total peripheral resistance. 4. The mean blood volume, plasma renin concentration and creatinine clearance were similar in eight hypertensive and 16 normotensive patients. Therefore the hypertension of stable renal transplant recipients is not related to blood volume expansion, elevated peripheral renin or low creatinine clearance. The cause of the elevated total peripheral resistance in hypertension in stable renal transplant recipients remains to be elucidated.

Adolescent↗
PubMed1978

Conversion of external arteriovenous hemodialysis shunt to internal fistula.

The preservation of arteriovenous (AV) access site is important to long-term survival of patient's requiring maintenance hemodialysis life-support therapy. Patients with chronic renal failure and uremia who are not suited for immediate application of a subcutaneous AV fistula or arteriovenous graft and who require an initial Teflon-Silastic AV shunt to initiate urgent hemodialysis need not lose these vessels when the AV shunt is removed. After venous maturation, these patients should have a subcutaneous AV fistula created from the uninfected, unclotted shunt before infection or clotting would cause loss of these vessels.

Arteriovenous Shunt, Surgical↗
PubMed1976

Management of breast lesions in children and adolescents.

The records of 207 patients evaluated and treated for breast abnormalities during a 10-yr period were reviewed. Patients ranged in age from 1 wk through 16 yr. Seventy-eight per cent were female. Operative procedures were performed in 134 patients (64%). Most common diagnoses were fibroadenoma, premature thelarche, and precocious puberty in the females, and pubertal gynecomastia in the males. Age and sex separate patients into natural subgroups. In females beyond the neonatal period, premature thelarche and precocious puberty are the most likely cause of breast enlargement. Breast biopsy is only rarely indicated for a distinct mass lesion in the prepubertal breast. Mass lesions in the breast of adolescent females require excisional biopsy. In the male, pubertal gynecomastia is the most common form of breast enlargement and only occasionally requires subcutaneous mastectomy for cosmetic and psychologic reasons. Careful evaluation of all children with breast enlargement is indicated to uncover underlying causes and to avoid unnecessary operative procedures.

Adenofibroma↗