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Biomedical subjects

J E Hoopes

Publications and source records attributed to J E Hoopes.

At least 37 records · Page 2Linked to original sources

Frontal cranioplasty: risk factors and choice of cranial vault reconstructive material.

A study of patients with large cranial defects involving the frontal bone, frontal sinus, nose, and orbit does not support the contention that there is a clear superiority of reconstructive material despite a history of previous bone infection. No patient with an isolated cranial reconstruction experienced an infection despite location in the area of the frontal sinus or the use of acrylic material. All patients experiencing infection underwent simultaneous reconstruction of the frontal cranium and nose and three- or four-wall reconstruction of the orbit, where the frontal sinus had previously been eliminated and where a previous bone infection had been present. Risk factors associated with cranioplasty were timing (p = 0.001) and cranial vault reconstruction in communication with previously infected ethmoid sinuses and the nose (p = 0.03). A history of previous bone infection suggests increased risk (p = 0.15). The choice of reconstructive material was not significant, although acrylic cranioplasties did not experience the complications expected from a review of the literature.

Adult↗

Effects of superoxide dismutase and allopurinol on the survival of acute island skin flaps.

We have demonstrated previously that oxygen-derived free radicals are important mediators of tissue injury following ischemia (total venous occlusion) and reperfusion in small (3 cm X 6 cm) island skin flaps in rats. In this study, we evaluated extension of this concept to regional ischemia in large (8 cm X 8 cm) acute island skin flaps which were constructed to exceed their sole blood supply via unilateral inferior epigastric vessels. Under normal (control) circumstances, a significant portion of the flap would undergo necrosis at the periphery, mimicking the corresponding clinical situation. Blocking the generation of superoxide radicals from xanthine oxidase with a single dose of allopurinol prior to flap elevation significantly improved the area of flap viability from 34 +/- 12% to 57 +/- 6% (p less than 0.01) in the random portion of the flap, contralateral to the source of blood supply. Similarly, the detoxification of superoxide radicals with a single dose of superoxide dismutase improved viability from 41 +/- 6% to 58 +/- 7% (p less than 0.01). Similar results were obtained when either of these agents were administered 60 minutes after flap elevation. These findings suggest that oxygen-derived free radicals play an important role in the development of tissue necrosis in the critical transition zone between well-vascularized and devascularized skin.

Allopurinol↗

Epithelioid sarcoma of the upper extremity.

Three cases of epithelioid sarcoma of the upper extremity are presented. Information regarding 112 previously published cases is reviewed. It is concluded that epithelioid sarcoma must be included in the differential diagnosis of soft-tissue tumors of the extremities. Moreover, the diagnosis of epithelioid sarcoma demands prompt and aggressive surgical intervention. Irradiation therapy and chemotherapy have not been proven to be of value in the management of epithelioid sarcoma.

Adolescent↗

Midface fractures: advantages of immediate extended open reduction and bone grafting.

Experience with 240 midface (Le Fort and zygoma) fractures in multiple trauma patients has emphasized that superior aesthetic results are obtained by immediate extended open reduction with primary bone grafting. Internal fixation of 110 zygomatic and 130 Le Fort fractures was performed in the lower midface (zygomaticomaxillary and nasomaxillary buttresses). Open reduction of the condyle was employed in five concomitant Le Fort and subcondylar fractures with a loss of ramus height to prevent superior and posterior displacement of the middle and lower face. Bone grafts were utilized in 74 patients. They were most frequently employed in the orbit and less frequently in the lower midface. Bone graft survival paralleled that observed under elective conditions, and a slightly higher infection rate was observed. Extended open reduction and immediate bone grafting adds a new dimension to the aesthetic results obtained from facial fracture treatment. Structural bony integrity and pre-injury facial architecture may be restored in the absence of soft-tissue contracture. Restoration of the pre-injury facial architecture (the essence of facial fracture treatment) is more accurately accomplished when these techniques are utilized.

Bone Transplantation↗

Effects of hyperbaric oxygen and hyperbaric air on the survival of island skin flaps.

The effects of hyperbaric air and oxygen on skin survival were studied in acute 8 X 8 cm neurovascular island flaps in rats. Skin flaps treated with hyperbaric 8% oxygen (equivalent to room air at standard pressure) exhibited no improvement in skin survival. Skin flaps treated with hyperbaric air (21% oxygen) and hyperbaric 100% oxygen exhibited significant increases in survival.

Air↗

Effect of allopurinol on the survival of hyperemic island skin flaps.

Allopurinol was investigated in 3 x 6 cm congested island skin flaps in rats. Eight hours of venous occlusion produced total flap necrosis. Pretreatment with systemic allopurinol, an inhibitor of xanthine oxidase, enhanced the survival rate of hyperemic skin flaps. Xanthine oxidase activities were demonstrated in skin, and these enzyme activities were noted to increase in skin flaps during ischemia and reperfusion. Much of this increase in enzyme activity was prevented by allopurinol treatment. The xanthine oxidase system appears to be one of the sources of the superoxide radical, which may be involved in ischemic and reperfusion injury in skin.

Allopurinol↗

Increases in acid proteinase activity during epidermal wound healing.

Incised wounds were made on the backs of young guinea pigs at 0, 1, 2, 3, 4, and 10 day intervals. Hemoglobin-hydrolizing acid proteinase activity was measured fluorometrically under optimal assay conditions by means of microanalytical methods. Acid proteinase activity was increased two to three times normal during epithelial migration and maturation during wound healing: no gradient of enzyme activity was found from the wound margin to the tip of the migrating epithelium. The results suggest that acid proteinase promotes epithelial migration by proteolytic action on serum protein and fibrin in wounds. It is also suggested that acid proteinase is required during epithelial maturation and differentiation.

Acid Phosphatase↗

Effects of levator retrodisplacement on conductive hearing loss in the cleft palate patient.

The effect of a levator retrodisplacement procedure upon conductive hearing loss in cleft palate patients was evaluated. Forty-two children with cleft palates, operated upon between 1970 and 1975, were included in the study. The results suggest that 73.5% of those in the levator retrodisplacement group achieved normal hearing, compared with 37.5% among those whose palatoplasties did not include levator retrodisplacement. The degree of hearing impairment in patients with levator retrodisplacement was mild (20 to 40 db) in contrast to that in patients without levator retrodisplacement, whose impairment was severe (40 to 60 db).

Cleft Palate↗

Hemipalatal palsy and microtia.

Unilateral microtia is not a separate entity but rather a part of the syndrome of hemifacial microsomia. To document the high incidence of hemipalatal palsy among microtia patients, 19 patients with unilateral microtia are reviewed. Partial innervation of the levator veli palatini muscle by the VII cranial nerve, and origin of this muscle from the second branchial arch, are suggested as the basis of the inclusion of hemipalatal palsy in hemifacial microsomia.

Child↗

The role of oxygen-free radicals in ischemic tissue injury in island skin flaps.

The contribution of free radical-mediated reperfusion injury to the ischemic damage caused by total venous occlusion of island skin flaps was investigated in a standardized rat model. Control flaps subjected to 8 hours of total venous occlusion showed complete, full thickness necrosis when followed for 7 days following release of the vascular occlusion. Treatment with superoxide dismutase, a scavenger of superoxide radicals, prior to and immediately following the onset of reperfusion, significantly enhanced island flap survival from 0/11 (0%) to 8/15 (53%), p less than 0.005, and from 0/9 (0%) to 6/12 (50%), p less than 0.02, respectively. These findings are consistent with the hypothesis that oxygen free radicals generated at the time of reperfusion following a period of ischemia contribute significantly to the ultimate damage caused by ischemic injury. Such findings are consistent with similar reported observations on other tissues and suggest a means by which ischemic tissue injury might be therapeutically modified, even after the period of ischemia.

Animals↗

Skin-flap metabolism in rats: oxygen consumption and lactate production.

Overall glucose metabolism was evaluated by measuring the rate of oxygen consumption (QO2) and lactate production in the pedicle skin flaps of rats. Skin flaps exhibited increases in QO2 and lactate production in vitro. The distal portion of the flap is characterized by a greater deposition of glucose to lactate during the initial 3 days following flap elevation. The contribution of glycolysis and of the oxidative pathways to glucose metabolism in skin flaps approximates that in normal skin on day 7 postoperatively.

Animals↗

Sagittal fractures of the maxilla and palate.

Sagittal fractures of the maxilla and palate are infrequent and can demonstrate significant instability with conventional methods of treatment. They require that rigid, horizontal stability of the dentition be obtained, as well as restoration of midface projection and height. The most effective and precise management has utilized a combination of open reduction and internal fixation at the piriform aperture and zygomatic buttress and posterior palate, use of a maxillary arch bar as a tension band, and utilization of a palatal splint.

Fracture Fixation, Internal↗

Increases in dihydronicotinamide adenine dinucleotide (NADH) content and alpha-glycerophosphate dehydrogenase activity in epidermal wound healing.

Alterations in NADH content and NAD-dependent dehydrogenase activity were determined in regenerating epithelium during wound healing in young guinea pigs. Regenerating epithelium exhibited increased levels of NADH. The migratory and proliferative phases of epidermal wound healing were characterized by increases in glycolytic enzyme activities, including an increase in lactate dehydrogenase (LDH). The maturation phase of epidermal wound healing was characterized by a maximal increase in alpha-glycerophosphate dehydrogenase (GOPDH) activity. The contrasting changes in LDH and GOPDH activity suggest that increased levels of NADH are utilized first by LDH in glycolysis during epidermal migration and proliferation and then by GOPDH in triacylglycerol synthesis during epidermal differentiation.

Animals↗

Head and neck surgery in the aged.

This study was carried out to determine the perioperative mortality rate of patients over the age of 65 years who are undergoing major head and neck resections under general anesthesia. The total number of patients was 810 and the perioperative mortality rate (death within 30 days of operation) was 3.5 percent (29 of 810). This rate is relatively low when compared with the rate for patients undergoing similar procedures during the same period in the 35 to 65 years age group. Since 1975 reports of other types of surgery in the elderly have given perioperative mortality rates of from 4.8 to 26 percent. Previous studies of head and neck surgery in the elderly have given perioperative mortality rates of from 1.3 to 13.6 percent. Head and neck surgery in the elderly continues to be a safe procedure when compared with other types of surgery. As the portion of patients in the population over the age of 65 continues to increase, advanced age alone should not be a deterrent to performing aggressive surgical therapy for head and neck cancer.

Aged↗

Tissue glucose and lactate following vascular occlusion in island skin flaps.

Neurovascular island skin flaps were elevated in the right groin area of Sprague-Dawley female rats weighing from 200 to 250 gm. Survival rates of the flaps were determined following venous and/or arterial occlusions of the femoral vessels. All the flaps exhibited an 80 percent decrease in tissue glucose content and an increase in tissue lactate content 4 to 7 times normal during venous and/or arterial occlusion. In the groups occluded for 8 hours, venous occlusion resulted in loss of all the flaps; arterial occlusion yielded survival of 70 percent of the flaps; and occlusion of both vessels yielded survival of 30 percent of the flaps. The results indicate that venous occlusion is more detrimental to flap survival than arterial occlusion. Surviving flaps exhibited a glucose content of 3.5 times normal, and dying flaps exhibited a glucose content of 20 percent of normal and a lactate content of 5.1 times normal. The ratio of tissue lactate to glucose may serve as an index for tissue viability: normal flaps, 0.3, surviving flaps, 1.2, and dying flaps, 7.5.

Animals↗

Nasolabial flap in intraoral reconstruction. Review of 55 cases.

The nasolabial skin flap has proved very useful in reconstruction of anterior intraoral defects after ablation for cancer. The technique allows immediate single-stage reconstruction with local tissue. Minimal functional or cosmetic deformity results at the donor site. Fifty-five consecutive patients who underwent anterior intraoral reconstruction with 68 nasolabial flaps were followed up for 1 to 10 years. Only two flaps were total failures. Three flaps had partial tissue loss. Successful reconstruction without complication was obtained with 93 percent of the flaps. Technical refinements and considerations in flap design are presented.

Adult↗