PubMed Health⌕ Search

Biomedical subjects

M F Angel

Publications and source records attributed to M F Angel.

At least 73 records · Page 4Linked to original sources
PubMed1988

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. There are, therefore, certain circumstances where the presence or absence of the buccal fat pad can create a specific imbalance and asymmetry in the face. The correction of these conditions may require reduction or augmentation. The anatomy, the risks, the classification, and the various surgical techniques that are available to accomplish this are outlined and correlated to the masseter muscle transfer.

Adipose Tissue↗
PubMed1988

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. Both children have near normal active range of motion. The transferred epiphyses have provided a major contribution to digital growth. The other two children had second toe proximal interphalangeal (PIP) joints transferred to damaged hand joints. Active PIP joint extension has been disappointing, and the overall growth contribution of the transferred epiphysis has been small. We conclude that MTP to metacarpophalangeal vascularized joint transfer can provide painless, functional, stable motion, with near normal growth potential, and the usefulness of toe PIP to hand PIP joint transfer is limited by the inability to achieve good active extension and limited growth potential.

Child↗
PubMed1988

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. A 10 X 3 cm dorsal rat flap was used, and tissue biopsies for xanthine oxidase and malonyldialdehyde (MDA) were obtained 2.5, 5.5, and 8.5 cm from the base of the flap at the hours given. In group I (control), the flap was outlined but not elevated, and biopsies were obtained. In group II, the flap was elevated, and biopsies were obtained at 6 hours. In group III, the flap was elevated, the distal 4 X 3 cm was amputated and replaced as a full-thickness skin graft, and biopsies were obtained at 6 hours. In group IV, the flap was elevated, and biopsies were obtained at 12 hours. In group V, the flap was treated as in group III, and biopsies were obtained at 12 hours. In group VI, the flap was elevated, and biopsies were obtained at 24 hours. In group VII, the flap was treated as in group III, and biopsies were obtained at 24 hours. RESULTS: Xanthine oxidase was significantly higher in all distal biopsies compared to proximal biopsies. Xanthine oxidase also increased with time. Malonyldialdehyde increased over time as well as with distance from the flap base. Distal flap biopsies at 24 hours had greatly increased levels of malonyldialdehyde compared to skin grafts (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1987

Augmentation of skin flap survival with allopurinol.

Although allopurinol is primarily known as an effective medication for gout, it has been shown to enhance tissue survival in a wide range of ischemic conditions. The study reported here investigated the effects of allopurinol on flap survival in a dorsal rat model. In a preliminary study, animals were given varying doses of allopurinol (0 to 400 mg per kilogram). A clinically efficacious dose was established upon conclusion of the test period by laboratory determinations and necropsy data. Other animals were divided into 3 groups: 1 (saline control), N = 11; 2 (50 mg per kilogram of allopurinol daily), N = 10; 3 (100 mg per kilogram of allopurinol qd), N = 11. Flaps were raised and necrosis assessed at 8 days. Flaps treated with allopurinol 100 mg per kilogram had significantly better survival than the controls (p less than 0.001) and 50 mg per kilogram (p less than 0.01). Allopurinol 50 mg per kilogram had no effect on flap survival.

Allopurinol↗
PubMed1987

A free radical scavenger reduces hematoma-induced flap necrosis in Fischer rats.

Free radicals have been shown to play an important role in hematoma-induced flap necrosis. The present study investigated the effect of deferoxamine, a free radical scavenger and iron chelator, on flap necrosis. A 4 X 2 cm dorsal flap was raised in Fischer inbred rats, and 3 cc of blood from inbred donors was instilled beneath the flap. Saline-treated control animals (Group 1) were compared with two experimental groups. In Group 2, deferoxamine 150 mg/kg was administered 15 minutes before surgery and every 8 hours for 5 days. In Group 3, deferoxamine was given every 8 hours for 3 days before surgery and every 8 hours for 5 days postoperatively. Flap necrosis was assessed on postoperative day 5. Group 2 had significantly less necrosis, 18.6%, than the control group, 64.0% (p less than 0.001). Group 3, with 36.0% necrosis, also showed improvement (p less than 0.05). Group 2 and Group 3 were not significantly different. Deferoxamine, a safe and well-tolerated free radical scavenger, greatly enhanced flap survival, presumably by the neutralization of damaging free radical species and by chelation of iron.

Animals↗
PubMed1986

Deferoxamine increases skin flap survival: additional evidence of free radical involvement in ischaemic flap surgery.

This study presents further evidence of free radical involvement in skin flap necrosis in a dorsal rat flap model. Rats receiving deferoxamine, a free radical scavenger and iron chelator had significantly less necrosis (p less than 0.001) than saline treated rats. In a separate experiment, tissue determinations for malonyldialdehyde (MDA) were consistent with the survival results in showing a significant decrease in MDA in all biopsy sites (p less than 0.05 or less), indicative of reduced lipoperoxidation in the deferoxamine treated rats.

Animals↗
PubMed1986

The influence of dexamethasone on the regrowth of surgically removed fat.

We investigated the interaction between long-term dexamethasone administration and lipectomy on regional fat deposits in the rat. Seven-week-old Sprague-Dawley rats (N = 24) were divided into 3 test groups. Group 1 (control) received 0.5 ml/kg of saline intramuscularly daily; group 2, 1 microgram dexamethasone intramuscularly; group 3, 5 micrograms dexamethasone intramuscularly. At week 9 a lipectomy of 4 regional fat deposits on the right side of the animal was done: inguinal, epididymal, interscapular, and perirenal. Injections continued for an additional 27 weeks, at which time a lipectomy was done removing left-sided depots in addition to any "regrown fat" on the previously dissected right side. Several conclusions can be made. First, rats receiving 5 micrograms/kg reaccumulated more fat than the controls in the inguinal, perirenal, and interscapular depots. Second, fat cell size in this model greatly influenced the ultimate size of each depot. Third, fat depots vary in their response to steroids and lipectomy because of local and systemic factors.

Adipose Tissue↗
PubMed1986

Studies on the nature of the flap/bed interaction in rodents--Part I: Flap survival under varying conditions.

A flap needs close contact with its bed for optimal flap survival. Using a rat dorsal flap model, flap/bed contact times were varied by use of a sterile polyethylene film. In addition, the flap was modified either by removing the panniculus carnosus or by converting the distal flap into a skin graft. Finally, the effect of using a dressing was assessed. Several observations were made: (1) The initial 6 to 12 hours of a flap's interaction with its bed is critical for optimal survival; (2) fluorescein accurately predicted flap survival upon polyethylene removal; (3) removing the panniculus carnosus increased flap and skin graft survival; (4) dressing allowed flaps and skin grafts to better withstand bed deprivation; and (5) distal flaps and skin grafts under various conditions responded differently to bed deprivation.

Animals↗
PubMed1986

Studies on the nature of the flap/bed interaction in rodents--Part II: Morphological and fluorescein kinetic data.

The current study in rats concerns two aspects of the flap/bed interaction: fluorescein kinetics and histological finding. In the control group of animals in the fluorescein kinetics experiment, flaps were raised and then reattached. In one experimental group, the flaps were raised and placed on a sterile polyethylene film. In two other groups, the flaps were raised and then the pedicle was cut, either immediately or at specific intervals. At intervals up to 24 hours several animals were injected with 5% fluorescein. In the control group fluorescein penetration increased with time, while it decreased in the polyethylene-film group. There was virtually no fluorescein staining in both cut-pedicle groups. To study histological events, the animals were divided into groups with flaps and groups in which the distal end of each flap was severed to form a contiguous skin graft. Other conditions were varied. All flaps were cultured, and biopsy specimens were obtained from three areas at several time intervals. Histological sections from the distal flap were markedly different from the corresponding skin grafts. These results corroborate previously noted survival rates.

Animals↗
PubMed1985

Vascularization of tricalcium phosphate, an artificial bone substitute: preliminary observations.

Tricalcium phosphate (TCP), a biodegradable artificial bone substitute, was used to study the following questions: i) can TCP be vascularized; ii) do ectopically placed implants have osteoinductive capacity; and iii) does vascularization affect implant resorption? Implants were placed in dogs in several areas: i) subcutaneous controls; ii) wrapped with latissimus dorsi muscle; iii) wrapped in omentum; iv) saphenous and thoracodorsal av pedicles threaded through implant. Prior to harvest, animals were given tetracycline and implants were harvested at 3, 6, and 9 weeks. Microfil was injected prior to sacrifice and specimens were xeroradiographed. Histology and computerized axial tomography were obtained. From this study, we conclude that 1) TCP can be vascularized; 2) the most effective method of vascularization was by an AV pedicle threaded through the implant; 3) vascularized implants did not have osteoinductive properties per se, and 4) in the time observed no difference in implant resorption was demonstrated between the test groups.

Animals↗
PubMed1985

Topical acidification promotes healing of experimental deep partial thickness skin burns: a randomized double-blind preliminary study.

The effects of three buffered solutions with pH values of 3.5, 7.42 and 8.5, respectively, on the healing rate of deep partial skin thickness burns, was followed for 21 days in 16 guinea-pigs. Two symmetrical burns were inflicted on the back of each animal and then each individual wound was dressed with an irrigation disc dressing; solutions were coded (no. 1 to no. 3) and the animals were randomly divided and blindly treated as follows: Group A, solution no. 1 v. solution no. 2 (n = 4); Group B, solution no. 2 v. solution no. 3(n = 4); Group C, solution no. 1 v. solution no. 3(n = 4); Group D, non-irrigated disc dressings (n = 4). The solutions were applied to the surface of the burn wounds at a rate of 0.15 ml/cm2. Dressings were changed every 7 days to assess contraction and epithelialization by a sonic digitizer. On post-burn day 21 the newly formed scar tissue was measured in all wounds. After computation of the healing rate at the end of the study, the data were then related to the coded treating agent. Contraction did not differ in all test groups during the study. Epithelialization was significantly faster in the pH 3.5-treated burns than in the other treated wounds (P less than 0.001). The present study indicates that topical acidification of experimental deep partial skin thickness burns promoted healing. The precise mechanism should be elucidated.

Administration, Topical↗
PubMed1985

The salutary effects of the bed on the survival of experimental flaps.

The present study indicates that the distal, random segment of an axial pattern experimental flap can be partially salvaged by employing local pressure, which provides favorable contact with the bed. This portion of the flap could be considered as a composite skin graft. Serial India ink injections demonstrated that its physiological take resembles that of a split-thickness graft, dominantly depending on the blood vessels emerging from its bed, and to a lesser extent on those provided by its proximal segment and adjacent skin edges. Increasing the topical flap humidity hindered, rather than improved, its survival.

Animals↗
PubMed1985

Effect of Fluosol-DA (20%) on skin flap survival in rats.

This study evaluates the effect of increased oxygen-carrying capacity of blood with the oxygen-carrying blood substitute Fluosol-DA (20%) on skin flap survival in rats. A skin flap model as described by Finseth was used in male Sprague-Dawley rats. We found that Fluosol-DA (20%) alone or in conjunction with O2 does not augment survival of skin flaps in rats, while hemodilution enhances and hemoconcentration deteriorates skin flap survival. Systemic O2 does not enhance survival of skin flaps in rats.

Animals↗