Biomedical subjects

R Trachy

Publications and source records attributed to R Trachy.

5 recordsLinked to original sources

PubMed1997

Topical FK506: a potent immunotherapy for alopecia areata? Studies using the Dundee experimental bald rat model.

We elected to examine the efficacy of the topically applied immunosuppressive agent FK506 (Prograf) in the treatment of alopecia areata (AA) using the Dundee experimental bald rat (DEBR) model. Thirty lesional DEBR rats were allocated to five groups of six. Group 1 rats received 0.1 mL of a 0.25% solution of FK506 within a 2 x 2 cm marked area on one bald flank twice a week (125 micrograms FK506/cm2 per week) for 8 weeks, while the contralateral flank was left untreated. In group II, 0.05 mL of a 0.1% solution of FK 506 was applied 5 days per week on one flank (62.5 micrograms FK506/ cm2 per week) and control vehicle to the opposite flank for 8 weeks. Group III rats were treated as in group II except that drug and vehicle were applied twice a week (25 micrograms FK506/cm2 per week) for 4 weeks. A positive control group received orally administered cyclosporin A (CsA) (10 mg/kg daily) for 8 weeks and a further group was left untreated. Rats were regularly examined and photographed with skin biopsies taken from groups II and III. All FK 506-treated rats regrew hair at the site of drug application within 14-21 days. Growth continued for 3 weeks beyond termination of treatment after which gradual hair loss was observed. No hair growth was seen as a result of vehicle application and hair loss continued on untreated areas and in the untreated control group. Immunohistology revealed a drastic reduction in the follicular inflammatory infiltrate at the site of the FK506 application. The oral CsA group responded by simultaneous regrowth of hair over the whole body. Our findings suggest that FK506 may have considerable potential as a topical treatment for AA.

Alopecia Areata↗

PubMed1987

Effect of dimethyl sulfoxide on island flap perfusion and survival in rats.

Investigations of the effect of dimethyl sulfoxide (DMSO) on skin flap survival have generated mixed results. In addition, to our knowledge, the effect of systemic DMSO on skin flap blood perfusion has not been previously studied. For this study, 48 rats were divided into three groups: (1) a control group, (2) a group injected with DMSO postoperatively only (for seven days), and (3) a preoperatively injected group (for three days preoperatively and seven days postoperatively). The DMSO was given intraperitoneally at a dose of 1.5 g/kg. On each rat, an abdominal island flap (3 X 6 cm) was raised and restored to its original site. Laser Doppler velocimetry and perfusion fluorometry were used to monitor flap perfusion immediately following surgery (day 0) and on postoperative day 3. Flap survival was significantly greater in the DMSO-treated groups when compared with the control group. Significant increases in blood perfusion were noted in the treated flaps on day 3.

Animals↗

PubMed1986

End-to-end and end-to-side microvascular anastomoses: a comparative study.

The decision to use an end-to-end versus end-to-side anastomosis remains a controversial issue in microvascular surgery, although it is generally accepted that certain clinical situations require skills in both techniques (eg, vessel size discrepancy or the need to preserve donor vessel distal flow). Using rats, this investigation presents a unique free flap model comparing not only arterial end-to-end and end-to-side anastomoses, but venous anastomoses as well. There were 15 animals in each anastomosis group with a greater than 80% flap survival rate in each group. This supports findings of earlier studies that suggested no difference in survival when these two anastomosis types were compared. Equally important was the assessment of dermofluorometry as an immediate postoperative perfusion monitoring device. In this model, fluorometry was not found to be useful for predicting flap viability in an early period after completion of the anastomoses.

Animals↗

PubMed1981

Rhomboid flap dynamics.

The rhomboid flap is a reliable, versatile, and widely used tool in head and neck surgery. Although its geometry is well described, the mechanics of the flap have not been scientifically investigated. For example, there is disagreement whether the maximum tension is located at the closure of the donor site or at the tip of the flap. An experimental model using piglets and stabilized force gauges has been developed to measure the distribution of tension in a standard Limberg flap (60 degrees rhomboid). Variables evaluated include the size of the rhomboid, the amount of undermining, and the position of the flap on the animal. Consistent measurements show tension at the closure of the donor site to represent the majority of tension around the flap (58% average); the size of the rhomboid and degree of undermining do not change relative tensions. A composite figure discloses the relationship of the initially outlined flap to the final result and quantifies the observable changes in the length of sides.

Animals↗

PubMedDate not supplied

Muscle transposition in the rehabilitation of the paralyzed larynx.

Muscle transposition of the innervated omohyoid muscle into the tendon of the paralyzed posterior cricoarytenoid muscle was studied in a small series of subhuman primates. A similar procedure was described previously by King for treatment of bilateral recurrent nerve injuries. Our studies confirm that this procedure adequately enlarges the airway to allow normal activity without a tracheostomy. Histologic studies appear to show nerve ingrowth occurring at 6 months as in other neuromuscular pedicle procedures. The procedure is easily performed and causes no other muscle denervation.

Animals↗