Secondary ischemia time in rodents: contrasting complete pedicle interruption with venous obstruction.

The current study investigated the effect of secondary ischemic insults on ultimate flap survival. Rodent skin flaps subjected to 8 hours of secondary ischemia with total pedicle obstruction had 56 percent survival (7 of 12) compared with primary ischemic flaps of the same time, which all survived. At 10 hours of ischemia, only 42 percent of secondary ischemic flaps survived compared with 67 percent (8 of 12) of primary ischemic flaps.

Effect of a thromboxane synthetase inhibitor UK-38,485 on the tolerance of skin flaps of primary ischaemia.

The harmful effects of ischaemia or skin flaps were modified using the thromboxane synthetase inhibitor UK-38,485. The epigastric island flaps of Sprague-Dawley rats (n = 288) were subjected to 10, 12 or 14 h of total pedicle occlusion, or 3, 5 or 7 h of venous occlusion of the sole vascular pedicle. Within each time period, rats received intravenous doses of either physiological saline (controls) or UK-38,485 at the beginning or end of the ischaemic episode.

Comparative haemodynamic effects of intravenous nisoldipine and hydralazine in congestive heart failure.

The acute haemodynamic effects of intravenous nisoldipine and hydralazine were compared in nine patients with heart failure. Both agents caused qualitatively similar effects, reducing both left ventricular preload and afterload, with reductions in systemic vascular resistance and increases in cardiac output. However, the effect of hydralazine was significantly greater and of longer duration than nisoldipine, and was associated with side effects in four patients.

The anatomy of the subscapular artery and its effects on flap design in the rabbit.

The course of the subscapular artery was studied in 20 rabbits. Its course was constant, giving two branches to the latissimus dorsi muscle after which the vessel sent a branch (S1) that perforated the panniculus carnosus to supply a large territory of skin. In a separate experiment, the contribution of the S1 branch to the viability of the rabbit latissimus dorsi musculocutaneous flap was evaluated.

Interaction between thromboxane and free radical mechanisms in experimental ischaemic rabbit skin flaps.

The possible relationship between increased blood levels of thromboxane (TXA2) and tissue levels of free radicals during ischaemia was investigated. Rabbit epigastric skin flaps were subjected to 4 h of body temperature ischaemia, then infused with either the TXA2 synthetase inhibitor UK-38,485, the free radical scavenger superoxide dismutase (SOD), or both immediately prior to reperfusion. After 30 min of reperfusion, increases in the tissue levels of xanthine oxidase (XO) and malonyldialdehyde (MDA), both of which are indices of free radical generation and decreases in the tissue levels of SOD were found.

The beneficial effect of chlorpromazine on dorsal skin flap survival.

A 3 x 10-cm dorsal rat skin flap contains a distal portion that is poorly perfused. The dorsal flap served as a useful model to test hemodynamic properties of the vasodilatory drug chlorpromazine. A control group of flaps were treated with saline and the test group with chlorpromazine (15 mg/kg intraperitoneally).

The deleterious effect of arteriovenous flow reversal during experimental free muscle transfer.

Arteriovenous flow reversal (AVR) has been used experimentally to salvage ischemic limbs and to create novel skin flaps with some success. The clinical applicability of AVR in muscle by way of two arteriovenous anastomoses in the rabbit was investigated. Twenty-four rabbits were divided into two groups.

The use of split metatarsal osteocutaneous free flaps in palatal and alveolar defects.

A series of seven osteomucosal defects of the palate were closed by split metatarsal osteocutaneous free flaps. All seven patients had successful closure of their defects with minimal facial scarring and insignificant donor site morbidity. This procedure, performed in one stage, avoids the use of previously compromised local tissues and improves the blood supply to the area, thereby enhancing the subsequent indicated reconstruction of other damaged structures.

The effect of deferoxamine on tolerance to secondary ischaemia caused by venous obstruction.

The current study investigated the efficacy of deferoxamine for treating secondary ischaemia due to venous obstruction in a rodent epigastric pedicle flap model. Rats receiving one dose of the free radical scavenger and iron chelator deferoxamine (150 mg/kg) intravenously prior to reperfusion had a mild improvement in flap survival: 46% in controls, 77% in deferoxamine-treated. This was statistically significant at p less than 0.

Hydrostatic distention and pharmacological treatment of epinephrine-induced microarterial spasm.

The efficacy of using hydrodistention and vasodilatory drugs to relieve spasm in arteries was investigated. The femoral arteries of 64 rabbits (divided into five groups) were placed in spasm by the topical application of epinephrine (1 mg/ml). In group A (controls) vasospasm was induced without further treatment.

The effect of prior elevation of skin flaps and ischemia on blood thromboxane levels.

The physiological factors that allow for the survival of ischemic skin flaps have not been clearly elucidated. Previous work by others has shown that elevation of a flap 24 hours before an episode of complete ischemia significantly improved survival, presumably by delaying the onset of the no-reflow phenomenon. The current study, using an epigastric flap, investigated the role of thromboxane in these events by observing postischemic plasma levels of thromboxane B2, the stable metabolite of the short-lived thromboxane A2.

Digital distraction lengthening followed by free vascularized epiphyseal joint transfer.

This is the first report of combined digital distraction lengthening followed by free vascularized metatarsophalangeal joint transfer. This restored mobility, stability, length, and growth potential in the ring finger of the mutilated hand in a child.

The effect of time of vascular island skin flap elevation on tolerance to warm ischemia.

The effect of time of vascular island skin flap elevation on tolerance to a subsequent 12-hour period of warm ischemia was studied. Sixty rats were separated into five equal groups; the rat epigastric island flap was used as the model. In group 1 flaps were elevated and immediately subjected to 12 hours of complete ischemia by application of microvascular clamps to both artery and vein of the pedicle.

Prior elevation of vascular island skin flaps: intolerance to ischemia caused by venous obstruction.

Previous experiments in our laboratory have shown that prior elevated flaps, those elevated 24 hr prior to complete ischemia, are more tolerant of the ischemic insult than acutely ischemic flaps that have had no prior elevation. In the current study, the effect of prior elevation was observed on tolerance to ischemia caused by venous occlusion alone. Under these conditions, limited blood flow may be possible via the unclamped artery, so a state of partial ischemia exists.

Effect of phosphoenolpyruvate and adenosine triphosphate on rabbit skeletal muscle after ischaemia: preliminary biochemical study.

The present study examined the effect of phosphoenolpyruvate (PEP) and adenosine triphosphate (ATP) on rabbit skeletal muscle flap survival after warm ischaemia. Two muscle flap models, rectus femoris pedicle flap and latissimus dorsi free flap, were subjected to a total ischaemia of 4 hours at 37 degrees C and 20 degrees C, respectively. Immediately prior to revascularisation, the muscles were infused with either Hanks' balanced salt solution (BSS) or Hanks' BSS containing 200 mumol PEP and 6.

Long-term follow-up of free vascularized joint transfers to the hand in children.

Toe-to-hand vascularized joint transfers in four children were reviewed 6 to 8 years after operation (average, 6.6 years). Two children had vascularized metatarsophalangeal (MTP) joints.

Surgery on the buccal fat pad in masseter transfer.

The buccal fat pad is an essential anatomic structure in the esthetic presentation of the face. It may become hypertrophied, with fullness of the cheek, or atrophic, with a sunken appearance, or become a plus or minus factor in reconstruction in this area. Lipoma of this pad is extremely rare, but it must also be differentiated.

The critical relationship between free radicals and degrees of ischemia: evidence for tissue intolerance of marginal perfusion.

Unlabelled: Skin-flap ischemia has been associated with the presence of free radicals. In this study, two enzyme systems involved in free-radical metabolism were used to compare a distal skin flap to a skin graft. Forty-two rats were divided into several test groups.

Diagnosis of lung carcinoid with cutaneous hyperpigmentation eight years after bilateral adrenalectomy.

A 26-yr-old male was submitted to bilateral adrenalectomy in 1977 for Cushing's syndrome. Some months later he developed intense skin hyperpigmentation together with increased ACTH levels (149 to 4000 ng/l). The sellar region was always normal in X-ray studies.