Ronald H. Levine
University of Toronto
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Featured researches published by Ronald H. Levine.
Plastic and Reconstructive Surgery | 1999
Christine L. Tang; Mitchell H. Brown; Ronald H. Levine; Margaret Sloan; Nelson Chong; Eric J. Holowaty
In a recent study involving 27,500 women who had breast reduction surgery in Ontario, Canada, 17 women who were diagnosed as having breast cancer at the time of their breast reduction surgery were identified. The aims of this study were to (1) describe a population-based series of patients who had breast cancer diagnosed at the time of breast reduction, (2) describe the treatment of these cancers, and (3) compare their survival rate with survival in patients in the general population who had breast cancer. Information about these women, their treatment, and outcome was extracted from hospital records, pathology reports, and reports from regional cancer centers. The chance of finding an invasive breast cancer at the time of breast reduction was 0.06 percent, which is lower than what has been reported previously. Sixty-seven percent of these women were treated with total mastectomy. In the remaining 33 percent, who were treated with partial mastectomy, the entire tumor was removed at the time of breast reduction. Fifty percent of the women were treated with radiation, and 25 percent were treated with chemotherapy or hormonal therapy. Compared with women in the general population of Ontario who have breast cancer, women whose breast cancer is discovered during breast reduction surgery are more likely to be treated with complete mastectomy and less likely to be treated with radiotherapy or chemotherapy. Seventy-one percent of the breast reduction group were axillary node-negative at diagnosis, compared with 58 percent in the general population of women with breast cancer. Survival from breast cancer in women diagnosed at the time of breast reduction (88 percent, 5-year survival) was better than survival from breast cancer in the general population (77 percent). These findings suggest that cancers found in women at the time of breast reduction are less advanced, possibly because they are diagnosed at an earlier stage.
Plastic and Reconstructive Surgery | 2006
Jamie I. Spiegelman; Ronald H. Levine
Background: Abdominoplasty is one of the most commonly performed aesthetic procedures. In our practice, it has recently shifted toward outpatient care as the standard. In this study, the authors investigated the difference in short-term complications in outpatient and inpatient procedures in an office-based surgery clinic. Methods: A total of 69 consecutive abdominoplasty patients from a plastic surgeons office-based surgery clinic were reviewed retrospectively. Of these, there were 37 inpatients (mean age at time of operation, 41.2 years; range, 26 to 54 years) and 32 outpatients (mean age at time of operation, 37.5 years; range, 21 to 58 years). Each patient was reviewed for short-term complications, which included wound infection, wound dehiscence, seroma, and/or hematoma. Complications were correlated to inpatient and outpatient groups. Results: Four inpatients (10.8 percent) and one outpatient (3.1 percent) had wound infections, whereas two inpatients (5.4 percent) and two outpatients (6.2 percent) had wound dehiscence/marginal necrosis (a small area of surgical wound opening). The most common perioperative complication was seroma formation, which was seen in seven inpatients (18.9 percent) and eight outpatients (25.0 percent). The overall complication rate in this study was 30.4 percent (29.7 percent in inpatients and 31.2 percent in outpatients). There was no correlation between short-term complications and inpatient/outpatient status. Conclusion: These results demonstrate that abdominoplasties can be safely and effectively performed in an outpatient surgery clinic.
American Journal of Physiology-heart and Circulatory Physiology | 1999
Joan E. Lipa; Peter C. Neligan; Thérèse Perreault; Johanne Baribeau; Ronald H. Levine; Robert J. Knowlton; Cho Y. Pang
The aim of this project was to investigate the role of ETA and ETB receptors in the mediation of endothelin (ET)-1-induced vasoconstriction in human skin. This information should provide important insights into the design of pharmacological intervention against skin vasospasm induced by ET-1 in peripheral vascular disease or surgical trauma. Vasoconstriction in response to intra-arterial drug infusion in isolated perfused human skin flaps (8 × 18 cm) derived from dermolipectomy specimens was assessed by studying changes in skin perfusion and perfusion pressure under constant flow rate in each drug treatment ( n = 4). It was observed that ET-1 (10-10 to 10-8 M) and norepinephrine (NE, 10-8 to 10-5 M) caused skin vasoconstriction in a concentration-dependent manner, with the vasoconstrictor potency of ET-1 ∼200-fold higher than NE. The ETA-receptor antagonist BQ-123 but not the ETB-receptor antagonist BQ-788 blocked the vasoconstrictor effect of ET-1. This observation was confirmed by studying skin perfusion using the dermofluorometry technique. In addition, ETB-receptor agonists BQ-3020 and sarafotoxin S6c (10-9 to 10-6 M) did not evoke skin vasoconstriction. BQ-3020 also did not elicit skin vasoconstriction even in the presence of 10-5M of N ω-nitro-l-arginine methyl ester and indomethacin. Furthermore, results from saturable and competitive ET-1 radioligand membrane receptor binding assays revealed that high-affinity and capacity binding sites are predominantly the ETA receptor subtype in endothelium-denuded skin arteries and veins of 0.5-1.5 mm diameter, with an ETA-to-ETBreceptor ratio of 83:17 in arteries ( n= 5) and 78:22 in veins ( n = 7). Results from the present functional and radioligand receptor binding studies clearly indicate that ET-1 is a very potent vasoconstrictor in human skin and its vasoconstrictor effect is primarily mediated by ETAreceptors, with no significant participation from ETB receptors.The aim of this project was to investigate the role of ETA and ETB receptors in the mediation of endothelin (ET)-1-induced vasoconstriction in human skin. This information should provide important insights into the design of pharmacological intervention against skin vasospasm induced by ET-1 in peripheral vascular disease or surgical trauma. Vasoconstriction in response to intra-arterial drug infusion in isolated perfused human skin flaps (8 x 18 cm) derived from dermolipectomy specimens was assessed by studying changes in skin perfusion and perfusion pressure under constant flow rate in each drug treatment (n = 4). It was observed that ET-1 (10(-10) to 10(-8) M) and norepinephrine (NE, 10(-8) to 10(-5) M) caused skin vasoconstriction in a concentration-dependent manner, with the vasoconstrictor potency of ET-1 approximately 200-fold higher than NE. The ETA-receptor antagonist BQ-123 but not the ETB-receptor antagonist BQ-788 blocked the vasoconstrictor effect of ET-1. This observation was confirmed by studying skin perfusion using the dermofluorometry technique. In addition, ETB-receptor agonists BQ-3020 and sarafotoxin S6c (10(-9) to 10(-6) M) did not evoke skin vasoconstriction. BQ-3020 also did not elicit skin vasoconstriction even in the presence of 10(-5) M of Nomega-nitro-L-arginine methyl ester and indomethacin. Furthermore, results from saturable and competitive ET-1 radioligand membrane receptor binding assays revealed that high-affinity and capacity binding sites are predominantly the ETA receptor subtype in endothelium-denuded skin arteries and veins of 0.5-1.5 mm diameter, with an ETA-to-ETB receptor ratio of 83:17 in arteries (n = 5) and 78:22 in veins (n = 7). Results from the present functional and radioligand receptor binding studies clearly indicate that ET-1 is a very potent vasoconstrictor in human skin and its vasoconstrictor effect is primarily mediated by ETA receptors, with no significant participation from ETB receptors.
Plastic and Reconstructive Surgery | 1991
Michael L. Kreidstein; Cho Y. Pang; Ronald H. Levine; Robert J. Knowlton
The design, isolated perfusion technique, and reactivity of a novel human skin-flap model are described. A transverse paraumbilical skin flap based on perforator vessels from the deep epigastric system was designed utilizing the tissue usually discarded following abdominal dermolipectomy. Within 3 hours of devascularization, a gassed (95% O2, 5% CO2), 37 degrees C Krebs-Henseleit buffer containing albumin (65 gm/liter) was pumped into the cannulated arterial pedicle of the skin flap and subsequently collected from the venous pedicle. Vascular resistance was continuously monitored and remained stable throughout the 4-hour perfusion. Lactate release was maintained throughout perfusion and was markedly increased by addition of insulin to the perfusate. Addition of norepinephrine to the perfusate resulted in a significant (p less than 0.05) dose-response increase in vascular resistance, and acetylcholine significantly (p less than 0.05) attenuated resistance in flaps preconstricted with norepinephrine. The results of these studies indicate that the isolated perfused human skin flap remained metabolically active with functionally intact vascular endothelium and smooth muscle throughout the 4-hour perfusion. The availability of this technique will, for the first time, permit laboratory study of human skin-flap pathophysiology and pharmacology.
Obesity Surgery | 1996
Lena Cazes; Mervyn Deitel; Ronald H. Levine
Background: Previous studies have found that people with apple (android)-shaped body fat distribution are at risk of developing cardiovascular disease, impaired glucose tolerance and hypertension. Methods: To investigate the effects of lipectomy, we measured lipid and lipoprotein levels, indices associated with glucose tolerance and blood-pressure. The tests were performed pre-operatively and 3 and 12 months post-operatively in 34 subjects (obese lipectomy patients with android-shaped body fat distribution) and 23 controls (obese breast reduction patients). Results: In subjects, total cholesterol, LDL and blood-pressure were significantly lower at 3 months follow-up, but returned to pre-operative levels at 12 months follow-up. Plasma insulin decreased significantly at 3 months follow-up, and continued to decrease at 12 months follow-up. Triglycerides, HDL, fasting blood sugar, glycosylated hemoglobin and C-peptide did not change at 3 and 12 months follow-up. There were no changes in controls. Conclusions: Lipectomy in patients with truncal obesity may reduce plasma insulin levels, but had no lasting effect on plasma lipids.
Annals of Plastic Surgery | 1996
William M. Kuzon; Rebecca Crawford; Paul Binhammer; Craig Fielding; Robert J. Knowlton; Ronald H. Levine
Thirty-eight patients with significant weight loss after vertical banded gastroplasty were studied prospectively while undergoing abdominal dermolipectomy to determine if the current intensity used during electrosurgical dissection influenced wound complication rates after this surgery. Patients were assigned randomly to one of two groups: (1) a HI group, in which the electrosurgical current intensity was set at a level that easily allowed coagulation of all vessels smaller than 0.5 mm in diameter or (2) a LO group, in which the current intensity was set at a much lower level that allowed dissection, but required that nearly all visible vessels be ligated separately. A standardized procedure was employed for all patients. The patients in the LO (N = 14) and HI (N = 24) groups were well matched for age, weight history, nutritional parameters, operative times, surgical blood loss, and postoperative hospital stay. The overall complication rates of 36% and 21%, and wound complication rates of 36% and 13% for the LO and HI groups, respectively, were not significantly different. These data indicate that using a relatively high electrosurgical. current intensity for dissection during abdominal lipectomy does not result in a higher wound complication rate.
British Journal of Plastic Surgery | 1995
Michael L. Kreidstein; Ronald H. Levine; Robert J. Knowlton; Cho Y. Pang
The applicability of serial skin surface fluorometry for repeated assessments of skin flap perfusion was investigated using the isolated perfused human transverse paraumbilical (TP) skin flap model. The flow rate, perfusion pressure and skin surface temperature were kept constant in seven human TP skin flaps and a low dose of fluorescein (3 x 10(-5) M) was used for each assessment. It was observed that the mean values for total dye fluorescence measured by a fluorometer and the maximum distance of perfusion estimated by dye fluorescein index remained consistent in five repeated assessments at 15 min interval. The variation in the maximum distance of perfusion within each TP skin flap over 5 repeated assessments was also relatively small, as judged by the mean coefficient of variation (6.1%; SEM 0.4%). Furthermore, a highly significant correlation between microsphere (15 microns) radioactivity index and dye fluorescence index was observed at corresponding locations in these seven TP skin flaps (r = 0.81; p < 0.001, n = 75). Taken together, these observations indicate that serial skin surface fluorometry provided consistent repeated assessments of skin perfusion in human skin flaps in vitro and the dye fluorescence index provided a consistent assessment of skin perfusion distance along the length of the TP skin flap. These observations lead us to speculate that critical (threshold) dye fluorescence index determined at various postoperative time points should be useful for prediction of skin viability in clinical skin flaps; thus, a clinical investigation is recommended.
Journal of Surgical Research | 2012
Ning Huang; Homa Ashrafpour; Ronald H. Levine; Peter C. Neligan; Joan E. Lipa; Cho Y. Pang
BACKGROUND Experimental evidence is accumulating to indicate that local acute vascular endothelial growth factor-165 (VEGF(165)) therapy is effective in attenuation of skin ischemia and increase in skin viability in rat skin flap surgery and the mechanism involves vasodilation induced by VEGF(165). So far, the vasodilator effect and mechanism of action of VEGF(165) have not been studied in human skin. The objective of this project is to test the hypothesis that VEGF(165) is also a potent vasodilator in human skin vasculature. MATERIALS AND METHODS We used an established isolated perfused human skin flap model and pharmacologic probes to demonstrate that VEGF(165) is a potent vasodilator in human skin vasculature and the mechanism involves activation of receptors and postreceptor signaling pathway, which in turn stimulates local synthesis/release of endothelial vasodilators. RESULTS We observed that VEGF(165) induced a concentration-dependent vasorelaxation in human skin flaps preconstricted with norephinephrine (8 × 10(-7)M; n = 7) or endothelin-1 (3 × 10(-9)M; n = 6). The vasorelaxation potency of VEGF(165) (pD(2) = 12.02 ± 0.25; n = 7) was higher (P < 0.05) than that of acetylcholine (pD(2) = 6.76 ± 0.06; n = 5) in human skin flaps preconstricted with 8 x 10(-7)M of norepinephrine. Using pharmacologic probes, we also detected that the vasorelaxation effect of VEGF(165) in the isolated perfused human skin flaps (n = 4) was triggered by activation of VEGF receptor-2. Furthermore, the postreceptor signaling pathway involved activation of Src family tyrosine kinase, phospholipase C, protein kinase C, an increase in inositol 1,4,5-triphosphate activity, a release of the intracellular Ca(2+) store, and finally synthesis/release of the endothelial nitric oxide (eNO) and prostacyclin and eNO predominantly mediated the vasodilator effect of VEGF(165) in the effector mechanism. CONCLUSION These findings support our hypothesis that VEGF(165) is a potent vasodilator in human skin vasculature and also provide important insights into the clinical study of local acute VEGF(165) therapy for prevention/treatment of skin ischemia in skin flap surgery.
Annals of Plastic Surgery | 1998
Christine L. Tang; Ronald H. Levine; Lalitha Shankar
We report an unusual case of malocclusion following a history of apparently blunt trauma. No maxillary or mandibular fractures were identified. The malocclusion persisted for several days. Finally computed tomography was performed, which revealed a foreign body in the infratemporal fossa. A 4-cm pencil was extracted from the patients right temporomandibular joint.
Archives of Plastic Surgery | 2016
Miliana Vojvodic; Kathryn V. Isaac; Ronald H. Levine; Leila Kasrai
Giant cutaneous horns (GCH) present as isolated skin lesions with large corneous components of considerable morphologic variation. Despite their striking clinical appearance, prevalence statistics are unknown due to their rarity. Diagnosis of the underlying pathology is essential for appropriate management, as a significant proportion of cutaneous horns arise in the setting of a cutaneous malignancy [1,2].