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Biomedical subjects

C Winslow

Publications and source records attributed to C Winslow.

8 recordsLinked to original sources
PubMed2001

A prospective comparison of scalpel versus bipolar scissors in the elevation of radial forearm fasciocutaneous free flaps.

OBJECTIVES/HYPOTHESIS: The radial forearm fasciocutaneous free flap has become the workhorse for reconstruction of head and neck ablative defects. A location distal to the head and neck allows this flap to be elevated concurrent with the ablation. Most commonly, the flap is elevated under tourniquet control. This involves a primary ischemic insult with a certain amount of hemorrhage after the tourniquet is released. Bipolar scissors are a new method of dissection. They may allow for a speedier dissection with a concomitant decrease in ischemic time. Their hemostatic properties may control hemorrhage after use of the tourniquet. STUDY DESIGN: A prospective study of patients undergoing radial forearm free flaps over a 12-month period at a tertiary care referral center was undertaken. RESULTS: Forty patients were entered into the study, flaps were elevated with scalpel (20) and with bipolar scissors (20). Mean time under tourniquet was 39 minutes (range, 30-56 min) with scalpel compared with 27 minutes (range, 21-31 min) with bipolar scissors (P <.001). Total mean time of elevation (including control of hemostasis and pedicle dissection) for scalpel elevation was 50 minutes (range, 35-61 min) compared with 32 minutes (range, 20-41 min) for bipolar scissors elevation (P <.001). Mean blood loss was 46 mL (range, 15-110 mL) in the scalpel elevation group compared with 14 mL (range, 0-50 mL) in the bipolar scissors elevation group (P <.001). Complications at the donor site were equal between groups. CONCLUSIONS: Bipolar scissors are a safe, efficient method for elevating radial forearm free flaps.

Dissection↗
PubMed2001

Effect of anemia on the fasciocutaneous flap survival in a rat model.

OBJECTIVE/HYPOTHESIS: Ablative surgery for head and neck cancer that creates large composite defects often results in a significant decrease in the hematocrit level. These defects are best reconstructed with a microvascular free tissue transfer. Effect of the decreased hematocrit on microvascular flap survival is controversial. The purpose of this study was to assess the effect of isovolemic anemia on flap survival in a rat model. STUDY DESIGN: Prospective analysis. METHODS: Ninety rats were used (30 control and 60 experimental animals). Experimental animals were rendered anemic by blood draw and volume resuscitated with either a colloid (30 animals) or crystalloid (30 animals) solution. In all animals a ventral fasciocutaneous flap was raised. A vascular clamp was applied to the arteriovenous pedicle, and different ischemic times were allowed to elapse before clamp removal. Flap survival was assessed at 5 days. Probit analysis was performed for the three animal groups. RESULTS: A significantly increased probability of the flap survival was found in the anemic animals compared with the control group (P < or = .05). No difference was found between the colloid and crystalloid resuscitation groups. CONCLUSIONS: A decreased hematocrit level increases fasciocutaneous flap tolerance to ischemia and significantly increases the primary ischemic time in the ventral flap clamp model in rats. Fluid replacement with either crystalloid or colloid produces identical results.

Anemia↗
PubMed1997

Cyclosporine as maintenance therapy in patients with severe psoriasis.

BACKGROUND: Low-dose cyclosporine therapy for severe plaque psoriasis is effective. Most side effects can be controlled by patient monitoring, with appropriate dose adjustment or pharmacologic intervention, or both, if indicated. Prevention or reversibility of laboratory and chemical abnormalities may be achieved by discontinuation of therapy after the induction of clearing. However, relapse occurs rapidly on discontinuation. Maintenance therapy with cyclosporine after induction has not been fully evaluated. OBJECTIVE: Our purpose was to compare a regimen of 3.0 mg/kg per day of oral cyclosporine with placebo in maintaining remission or improvement in patients with psoriasis. METHODS: After a 16-week unblinded induction phase in which 181 patients received cyclosporine, 5.0 mg/kg per day (an increase up to 6.0 mg/kg per day and a decrease to 3.0 mg/kg per day were allowed, if required, to achieve efficacy or tolerability, respectively), those patients showing a 70% decrease or more in involved body surface area (BSA) entered the 24-week maintenance phase and were randomly assigned to either placebo, cyclosporine, 1.5 mg/kg per day, or cyclosporine, 3.0 mg/kg per day. Patients were considered to have had a relapse when BSA returned to 50% or more of the prestudy baseline value. Clinical efficacy, adverse effects, and laboratory values were monitored regularly throughout both study phases. RESULTS: During induction, cyclosporine at approximately 5.0 mg/kg per day produced a reduction in BSA of 70% or more in 86% of the patients. During maintenance, the median time to relapse was 6 weeks in both the placebo and cyclosporine 1.5 mg/kg per day groups, but was longer than the 24-week maintenance period in the 3.0 mg/kg per day group (p < 0.001 vs placebo). By the end of the maintenance period, 42% of the patients in the 3.0 mg/kg per day cyclosporine group had a relapse compared with 84% in the placebo group. Changes in laboratory values associated with the higher induction dosage generally exhibited partial or complete return toward mean prestudy baseline values during the maintenance phase, with the greatest degree of normalization in the placebo group. CONCLUSION: Cyclosporine, 3.0 mg/kg per day, adequately and safely maintained 58% of patients with psoriasis for a 6-month period after clearing of their psoriasis with doses of approximately 5.0 mg/kg per day.

Administration, Oral↗
PubMed1994

Regional blood flow distribution in endotoxin-treated dogs: modification by ibuprofen.

PURPOSE: The aim of this study was to determine whether the improved hemodynamic profiles reported with cyclooxygenase inhibition during sepsis include improvements in tissue perfusion is unknown. Our hypothesis was that cyclooxygenase inhibition with ibuprofen will prevent the endotoxin-induced alterations in regional blood flow distribution from developing and/or restore the endotoxin-induced loss of responsiveness to intravascular volume expansion. METHODS: We measured cardiac output, regional blood flow, and total systemic shunt flow in dogs using radiolabeled 15-microns microspheres. These parameters were assessed in control (N = 10) and endotoxin-treated animals (N = 7). Additional endotoxin-treated animals (N = 7) were also pretreated with ibuprofen. RESULTS: Compared with controls, endotoxin-treated animals exhibited marked reductions in blood flow to most systemic organs that were not reversed with large, intravenous saline infusions (ie, isotonic saline; 40 mL/kg; N = 4). By contrast, although ibuprofen pretreatment (12.5 mg/kg; N = 7) completely prevented the reductions in mean arterial pressure caused by endotoxin from occurring, it did little to prevent the development of endotoxin-induced alterations in regional blood flow distribution. Nonetheless, in contrast to the endotoxin-treated animals, there were significant increases in cardiac output and blood flow to several organs after saline infusion in the ibuprofen-pretreated animals. CONCLUSIONS: Cyclooxygenase inhibition with ibuprofen has few direct effects on regional blood flow distribution after endotoxin. However, cyclooxygenase inhibition with ibuprofen does attenuate the endotoxin-induced decrease in vascular responsiveness to intravenous saline infusion.

Animals↗
PubMed1990

Physiological regulation of the renal vasopressin receptor-effector pathway in dogs.

Physiological regulation of receptor-effector pathways is recognized as a significant factor determining target organ selectivity and sensitivity in several hormonal systems. Whether or not physiological regulation of the renal vasopressin (V2) receptor-effector pathway participates in the control of body fluid homeostasis is unknown. We evaluated four states likely to be associated with altered sensitivities of the renal V2 receptor-effector pathway as follows: dehydration (18-h hydropenia), volume expansion, exogenous arginine vasopressin (AVP) infusion (10 ng/kg + 0.25 ng.kg-1.h-1), and cyclooxygenase blockade (indomethacin, 2 mg/kg + 2 mg.kg-1.h-1) for effects on the antidiuretic efficacies and potencies of putative V2-receptor antagonists in conscious dogs. The antidiuretic efficacies of desGly9[Pmp1-D-Tyr(Et)2Val4]AVP [Smith Kline & French (SK&F) 101926; 0.01-1,000 micrograms/kg] ranged from that of a full agonist to that of an antagonist, depending on the physiological state studied. The vasopressin antagonist potency of SK&F 101926 was increased 150-fold in association with extracellular volume expansion and decreased by blockade of renal cyclooxygenase activity. This spectrum of activities is that anticipated for a partial agonist under conditions where receptor number and/or sensitivity of receptor-effector coupling is increased or decreased, respectively. Thus volume expansion and increased circulating vasopressin concentration are associated with effective decreases, whereas hydropenia and cyclooxygenase blockade are associated with effective increases in sensitivity of the renal V2 receptor-effector pathway in the dog kidney. We conclude that the V2 receptor-effector pathway is a site of integration of physiological mechanisms participating in the control of body fluid homeostasis in conscious dogs.

Animals↗
PubMedDate not supplied

Glutamine-antioxidant supplementation increases body cell mass in AIDS patients with weight loss: a randomized, double-blind controlled trial.

Loss of body cell mass, the active functioning tissue of the body, commonly occurs in patients with human immunodeficiency virus (HIV) infection, and the extent of wasting is related to the length of survival. We evaluated the anabolic role of the amino acid L-glutamine (GLN) and antioxidants in a double-blind, placebo-controlled trial in 26 patients with > 5% weight loss since disease onset. Subjects received GLN-antioxidants (40 g/d) in divided doses or glycine (40 g/d) as the placebo for 12 wk. Throughout the study, the subjects were seen weekly by a nutritionist, and body weight, bioelectric impedance assessment, and nutritional counseling were performed. Twenty-one subjects completed the study, and the groups were well matched. The 5 patients excluded from analysis all met a priori exclusion criteria. Over 3 mo, the GLN-antioxidant group gained 2.2 kg in body weight (3.2%), whereas the control group gained 0.3 kg (0.4%, P = 0.04 for difference between groups). The GLN-antioxidant group gained 1.8 kg in body cell mass, whereas the control group gained 0.4 kg (P = 0.007). Intracellular water increased in the GLN-antioxidant group but not in the control group. In conclusion, GLN-antioxidant nutrient supplementation can increase body weight, body cell mass, and intracellular water when compared with placebo supplementation. GLN-antioxidant supplementation provides a highly cost-effective therapy for the rehabilitation of HIV+ patients with weight loss.

Acquired Immunodeficiency Syndrome↗