Biomedical subjects
T Kaufman
Publications and source records attributed to T Kaufman.
Deep partial skin thickness burns: a reproducible animal model to study burn wound healing.
A reproducible deep partial skin thickness burn model using guinea-pigs to study the healing process of this injury is described. Round aluminium templates heated to 75 degrees C and applied for 5 s to the moistened, clipped and depilated dorsal skin produced the desired depth of injury. This model is applicable for the study of the three main components of the burn wound healing process: epithelialization, contraction and scar formation. It is recommended that the India ink injection technique be used to confirm the depth of the burn wound.
Is postburn dermal ischaemia enhanced by oxygen free radicals?
The accumulated data suggest that oxygen free radicals are actively involved in the pathophysiology of the wound healing process. Since OH. and O2- directly correlate with the release of arachidonic acid and catalyse some of the enzymes participating in its cascade, their involvement in the enhancement of dermal ischaemia in the stasis zone is postulated. Experimental data using topically applied scavengers of superoxide have shown their beneficial effects on the burn wound healing process.
Uterine angiogenic factor induces vascularization of collagen sponges in guinea-pigs.
The need for an adequate blood supply is of prime importance in successful skin grafting and in the take of keratinocyte cultures. Thus, the human uterine angiogenic factor (HUAF) extract, which induces neovascularization of the chorioallantoic membrane (CAM), was employed. The bioassay of HUAF was performed on an in vivo model of subdermally implanted collagen sponges and on sponges implanted into full skin thickness burn wounds in guinea-pigs. The HUAF extract was injected into the sponges every other day for 10 days. Each injection contained 10 micrograms decidual proteins with a total of 50 micrograms/sponge. The animals were sacrificed and the sponge together with the surrounding structures were extirpated, examined macro- and microscopically and by histological techniques. HUAF induced growth of blood vessels from the surrounding vascular bed into the implanted sponges. The angiogenesis was characterized by dense tortuous vessels with centripetal orientation. The control sponges exhibited only sporadic growth of blood vessels. This phenomenon repeated itself in the animals which were inflicted with burn wounds. The present study demonstrates that HUAF extract is also active on the in vivo model of experimental burns and wounds.
Evidence that 1 per cent Meshushit ointment prevents progressive dermal ischaemia of experimental deep partial skin thickness burns: a preliminary, quantitative controlled study.
This study quantitatively assessed the topical effects of Meshushit, a new herbal compound, on the healing process of experimental deep partial skin thickness burns over 27 days. To symmetrical circular burns were inflicted on the back of 15 animals by aluminium templates. The Meshushit and its control vehicle containing 0.1 per cent gentamycin or the control vehicle plus antibiotic alone, were applied topically to randomly selected burns at equal time intervals. Epithelialization and contraction were assessed on postburn days 6, 10, 15, 18, 22 and 27 using a computerized planimeter. The newly formed granulation tissue was assessed histologically on postburn day 27, while the hair follicles were counted in the same sections. Student's t test was used to differentiate the rates of contraction and epithelialization; hair follicle counts and the thickness of the newly formed granulation tissue. None of the animals died during the experiment. The epithelialization and contraction rates did not differ significantly between the test groups. The Meshushit-treated wounds showed a significantly thicker granulation tissue layer as compared to its control (828.72 +/- 46.39 microns vs. 540.78 +/- 37.81 microns, P less than 0.01). The count of hair follicles was significantly higher in the Meshushit-treated burns (23.38 +/- 1.84 vs. 3.76 +/- 0.35, P less than 0.001). It is concluded that the herbal Meshushit ointment enhanced the newly formed granulation tissue and preserved better the hair follicles in the present burn wound model. It is suggested that these findings are due to the preservation of the dermal microcirculation.
Aloe vera and burn wound healing.
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Responses to acute hypoxemia in fetal sheep at 0.6-0.7 gestation.
A majority of previous studies of fetal responses to acute hypoxemia has focused on the response of the sheep fetus greater than 120 days of gestation when many regulatory systems have been established. To assess the response of younger, less well-developed fetuses, we exposed two groups of fetal sheep (I, 84-91 days; II, 97-99 days gestational age) to acute hypoxemia by giving the ewe a gas mixture containing 9% O2 to breathe. We decreased descending aortic PO2 in both groups of fetuses [I, 24 +/- 6 to 14 +/- 3 (SD) Torr; II, 23 +/- 3 to 12 +/- 4 Torr] by a degree similar to that achieved in previous studies of fetuses greater than 120 days of gestation. Mean arterial blood pressure (I, 31 +/- 6; II, 40 +/- 3 Torr) did not change significantly from control values, and heart rate (I, 224 +/- 27; II, 203 +/- 16 beats/min) increased significantly in group II fetuses with hypoxemia. In group I and II fetuses, as in older fetuses, cerebral, myocardial, and adrenal blood flows, measured by the microsphere technique, increased, and pulmonary blood flow decreased. These responses mature early and are likely local vascular responses to decreases in oxygen content. Combined ventricular output and umbilical-placental blood flow decreased significantly in both groups. Unlike the response of the fetus greater than 120 days, acute hypoxemia did not decrease blood flow to the musculoskeletal and cutaneous circulations (group I only), gastrointestinal, or renal circulations.(ABSTRACT TRUNCATED AT 250 WORDS)
External longitudinal splitting of the biceps brachii muscle for coverage of repaired brachial vessels: an anatomical study and clinical application.
The external longitudinal splitting of the biceps brachii muscle offers a convenient and safe method for covering exposed vessels in the medial aspect of the arm in cases with loss of soft tissue. This anatomical study reveals rather variable and inconsistent patterns of blood supply to the biceps brachii muscle. The common denominator among the patterns is the fact that the nutrient vessels to the muscle originate in its posterior deep surface and course thereafter in a fan shape upward to the surface of the anterior aspect of the muscle. This microcirculatory pattern permits the external longitudinal splitting of the biceps brachii muscle along the whole anteromedial aspect of the short-headed belly without compromising its blood supply and function. An illustrative case is described.
The hypospadias silicone loop: a method to treat strictures of the distal reconstructed urethra.
The silicone loop was used to ensure patency of the distal urethra reconstructed by a tubularized full-thickness skin graft in patients with proximal or penoscrotal hypospadias. By this method we avoid repeated dilations of the urethra and the attendant anesthesia and discomfort to the patient.
Omiderm--is it beneficial for burns?
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Is experimental muscle flap temperature a reliable indicator of its viability?
This study was designed to assess the effects of environmental factors on experimental muscle flap temperature and to critically evaluate temperature as a modality for assessing vascular patency. A brief overview of the physiology of tissue heat transfer is presented. The right vertebral head of the biceps femoris muscle was used in albino New Zealand rabbits for monitoring temperature. Temperature was recorded simultaneously by means of thermocouples placed into the tested muscle, the contralateral control biceps femoris muscle, the ipsilateral control thigh compartment, and rectally (core temperature). The muscle flap temperature was recorded as a function of time during the following flap manipulations: steady state, exposed muscle, muscle elevated and then replaced with pedicles intact, and pedicles ligated. In addition, the effects of environmental manipulations on muscle flap temperature were evaluated. The constant findings demonstrated that the dominant aspects of muscle temperature are the temperature of the surrounding tissue, as well as the prevailing environmental conditions. Vascular occlusion did not alter muscle temperature. In 3 patients who underwent successful free-flap transfer, muscle temperatures were monitored and found to be labile, and altered by environmental manipulations. We concluded that temperature is an unreliable, nonreproducible method of assessing the vascular status of a muscle flap, unless all environmental variables are meticulously monitored and controlled.
Early enteral nutrition for mass burn injury: the revised egg-rich diet.
An aggressive enteral nutritional approach has been employed to support our severely burned patients. The diet is based on a daily intake of 5 eggs/10 kg of body weight, incorporated into milkshakes. Twelve patients with severe burns (age, 24 +/- 4 years; burns, 54 +/- 12 per cent of total body surface area (TBSA] were studied. Enteral feeding was initiated on the day of injury and gradually reached the full formula within 3-7 days. Feeding was carried out either orally or through a nasogastric drip or a combination of both, depending on the patient's condition. Each bottle of milkshake contained 2318 kJ, 29 g protein, 51 g carbohydrate and 28.6 g fat in 250 ml. Each millilitre of the diet contained 9.32 kJ. The protein provided 21 per cent of the total calorie intake, while the fat and carbohydrate provided 42 per cent and 37 per cent respectively. The mean daily intake consisted of protein (5 +/- 1.5 g/kg), carbohydrate (8 +/- 0.75 g/kg) and fat (5 +/- 1 g/kg), providing a daily administration of 378-420 kJ/kg. Plasma lipids remained within normal limits during the 40 days of the diet, while serum protein levels rose to normal levels within the first 3 weeks.
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.
Reconstruction of the tip of the nose and ala by load cycling of the nasal skin and harnessing of extra skin.
Reconstruction for loss of the nasal tip, adjoining columella, and left ala was largely accomplished by means of load cycling of the skin of the nose. The harnessing of the skin's viscoelastic properties can yield a fairly significant amount of extra skin, thus enabling a rather complicated problem to be dealt with by a relatively simple maneuver.
The microcirculatory pattern of the transverse-abdominal flap: a cross-sectional xerographic and CAT scanning study.
Following unilateral iliac artery injection of radiopaque Microfil in cadavers, coronal sections of the anterior abdominal wall at 1-cm intervals were obtained employing computerized axial tomography of the intact specimen as well as xerography of frozen slices. Because they avoid the distortion and disruption of the vasculature induced by anatomical dissection, these studies clearly indicate that the arterial supply to zones 3 and 4 of the transverse rectus abdominis musculocutaneous flap is derived through the following systems: the subdermal plexus, and the superficial subcutaneous tissue crossover system. This study substantiates previous anatomical assumptions.
[Hyperbaric oxygen for postirradiation osteomyelitis of the chest wall].
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Silent perforations of the stomach and duodenum by needles.
We present a series of ten patients consecutively admitted to the hospital after swallowing 12 household sewing needles. Ten of these needles, one in each patient, had perforated either the stomach or the duodenum, but in no case did the perforation cause any abdominal symptoms or signs. Immediately after arrival in the emergency ward, the diagnosis was made in most cases by means of a diatrizoate meglumine swallow, which showed the tip of the needle protruding outside the gastrointestinal tract. In the first few cases, the diagnosis was made by finding the needle in the same position after repeated plain abdominal roentgenograms. This method, however, served to delay the diagnosis of perforation. All patients were operated on immediately after the diagnosis of perforation was made, except for two who had an additional ingested needle. Operation was delayed in these patients until the second needle was spontaneously eliminated. Perforation was confirmed by operation in all cases in the present series, the operative extraction of the needle was simple, and recovery was uneventful. The fact that patients may remain asymptomatic despite perforation of their stomach or duodenum by sharp, fine foreign bodies is no cause for procrastination of surgery, as severe complications may subsequently result.
Effect of an egg-rich diet on plasma lipids and proteins in severely burned patients.
Eight severely burned young patients were maintained on an oral hyperalimentation regimen of about 7,000 calories--including 314 proteins, 600 g carbohydrates and 336 g fats, containing greater than 8 g cholesterol--based mainly on a daily ingestion of 35 eggs. Serum cholesterol and protein, and plasma lipoprotein levels were measured during period of 30 days on the diet. The mean serum cholesterol level prior to the egg-rich diet was low [108 +/- 42 (SD) mg/dl] and it remained within the normal range during the study. The initial mean serum total protein level of 4.1 +/- 0.5 (SD) rose to 6.5 +/- 0.7 g/dl by the 19th day and stayed high throughout the remainder of the study. Plasma lipoprotein levels, assessed by nephelometry and reported as concentrations of large, medium and small particles, were not increased. It is assumed that the high demand for energy during recovery from burns prevented abnormal rises in plasma lipid levels on fat-rich diet.