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Biomedical subjects

D W Furnas

Publications and source records attributed to D W Furnas.

At least 19 recordsLinked to original sources
PubMed1991

Transplantation of vascularized composite mandibular allografts in young cynomolgus monkeys.

In the search for donor tissue for massive craniofacial defects, the transplantation of somatic tissue allografts was explored. Four young, out-bred cynomolgus monkeys were the recipients of orthotopic hemimandibular allotransplants from nonrelated cynomolgus monkeys. The transplant consisted of one-half of the mandible with attached muscle, skin, and mucosa. Cyclosporine 15 mg/kg/day was given subcutaneously each day. The 4 monkeys were observed for 13, 27, 63, and 65 days, respectively. All transplants showed primary wound healing and hair growth. The 2 longest survivors chewed, ate a normal diet, and gained weight. Two allografts showed severe rejection signs at 2 to 3 weeks, and the monkeys were euthanized. One monkey had a second episode of rejection that could not be reversed, and it was killed. The fourth monkey died of undetermined causes.

Animals↗
PubMed1991

Growth of vascularized composite mandibular allografts in young rabbits.

Forty-one hemimandible allografts were transplanted in young rabbits immunosuppressed with cyclosporine. The majority of the grafts demonstrated normal wound healing, and growth of hair, bone, and teeth. The mandibular body and the premolars showed significant growth in length. The allografted mandibles functioned sufficiently that the rabbits took oral nourishment soon after surgery. Long-term survival was limited by a toxic "wasting syndrome" specific for rabbits under treatment with cyclosporine.

Animals↗
PubMed1990

Lethal cyclosporine associated toxicity in the rabbit: similar findings in two distant and independent transplant laboratories.

A collaborative study was initiated between Basel and Irvine Laboratories named above in an attempt to characterize a unique and lethal gastrointestinal toxicity in rabbits associated with cyclosporine administration. Data from both laboratories were combined and analyzed. The rate of weight loss in CsA treated rabbits was found to be a significant linear function of the dose. In addition, animal survival decreased and showed a dose-dependent linear relationship to CsA use. Grossly, all of the animals presented with full stomachs, incompletely digested, dry, hard, rabbit chow. Histopathology could not provide any insight into the mechanisms of this gross finding and remain unclear. The complete similarity of clinical and histopathological results in distant independent laboratories confirms the specificity of this CsA associated toxicity in the rabbit.

Animals↗
PubMed1990

Complications of surgery of the external ear.

The external ear has intrinsic anatomical vulnerabilities that invite surgical complications. Among these are the exposed position of the auricle, the thinness of the skin, and subcutaneous cover; the delicate convoluted shape; and the avascularity of the underlying auricular cartilage. Certain complications of surgery such as infection, bleeding, and hypertrophic scars are shared in common with operative procedures elsewhere on the body. Other complications are specific to otoplasty, to ear reconstruction, and to other individual ear procedures. This article outlines the means of recognition, treatment, and prevention of complications in surgery of the external ear.

Adult↗
PubMed1989

Growth of forelimb allografts in young rabbits immunosuppressed with cyclosporine.

Seventeen forelimbs were transplanted orthotopically from young Dutch rabbits to young New Zealand rabbits treated with cyclosporine. The transplanted limbs demonstrated significant bone growth. The growth in the transplanted limbs was about 75 to 80% of that observed in the unoperated limb. The long bones of the 3 longest surviving rabbits (133 days, 150 days, 150 days) studied radiographically demonstrated increases in length over their original lengths (humerus 22%, ulna 26%, and radius 31%). Hair and nail growth were noted at about day 10. Response to pain stimuli (withdrawal of forelimb) and functional use (ambulation with 50% weight bearing) was seen at two to three months. Permanent survival was not achieved because of a species-specific toxic wasting syndrome from cyclosporine.

Animals↗
PubMed1989

The retaining ligaments of the cheek.

The zygomatic ligaments (McGregor's patch) anchor the skin of the cheek to the inferior border of the zygoma just posterior to the origin of the zygomaticus minor muscle. The mandibular ligaments tether the overlying skin to the anterior mandible. Both these ligaments are obstacles to surgical maneuvers intended to advance the overlying skin. They also restrain the facial skin against gravitational changes, and they delineate the anterior border of the "jowl" area. The platysma-auricular ligament is a thin fascial sheet that extends from the posterosuperior border of the platysma and that is intimately attached to the periauricular skin; it serves as a surgical guide to the posterosuperior border of the platysma. The anterior platysma-cutaneous ligaments are variable fascial condensations that anchor the SMAS and platysma to the dermis. They can cause anatomic disorientation with dissection of false planes into the dermis. These four ligaments are useful as anatomic landmarks during facial dissections. The tethering effects of the zygomatic and mandibular ligaments must be interrupted if a maximum upward movement of the facial skin is desired.

Cheek↗
PubMed1988

An ideal headlamp for overseas surgery.

A battery-powered headlamp with a point-source halogen bulb and rechargeable batteries is ideal for operating in underdeveloped facilities. It offers a coaxial light source that rivals the quality of fiberoptic illumination.

Humans↗
PubMed1987

Temporal osteocutaneous island flaps for complete reconstruction of cleft palate defects.

In each of four patients, closure of a wide cleft palate was performed with a temporal osteocutaneous island flap (TOCI flap) based on the superficial temporal artery. These were fabricated island fasciocutaneous flaps composed of temporoparietalis fascia and galea with pericranium, surfaced with split skin grafts. Two flaps carried with them a segment of vascularized parietal bone (TOCI-I). In the other two flaps, the osseus component was supplied by placing an osteogenic powder in a pericranial pocket: a temporal artery "osteogenic" cutaneous flap (TOCI-II). In each case the flap closed the defect and lengthened the palate without the need for elevation of palatal mucoperiosteum. Growth of the parietal bone segment has been observed in the first patient (the only one to have a follow-up CT scan). This patient, the eldest, is developing normal speech so far. The others are still too young for evaluation.

Cleft Palate↗
PubMed1986

Composite tissue (limb) allografts in rats. III. Development of donor-host lymphoid chimeras in long-term survivors.

Eight LEW rat recipients possessing long-term-surviving (206-701 days) LBN vascularized hind limb allografts (CTAs) were tested for donor-host lymphoid chimerism. The recipients received various cyclosporine (CsA) treatment protocols in order to induce indefinite CTA acceptance. Histological examination of long-term-surviving CTAs demonstrated normal-appearing bone marrow in the donor limb. Lymphocytes isolated from host hemopoietic tissues (peripheral blood and/or spleen) by ficoll-hypaque density gradient centrifugation were tested against LEW-anti-BN antisera. Comparisons were made to standard curves employing various known concentrations of LBN and LEW cell combinations. The level of lymphocyte agglutination (dependent variable) showed a significant (P less than 0.025-0.005) linear relationship to the concentration of LBN donor cells (independent variable) present. Lymphocyte suspensions isolated from long-term CTA host peripheral blood and/or spleen showed a mean of 19.7% (+/- 9.7-95% confidence interval) donor LBN mononuclear cells present. Thus, it appeared that lymphoid cells originated from, and/or were released from LBN donor bone marrow into the circulation, resulting in chimeric repopulation of hemopoietic tissues. The presence of donor immunocytes in these limb allograft recipients may have been beneficial, and thus could have helped contribute to the long-term CTA survival observed.

Animals↗
PubMed1985

Traditional craniotomies of the Kisii tribe of Kenya.

Our research team has reviewed the practice of traditional craniotomy by the ababari emetwe (craniotomists) of the Kisii tribe of Kenya through interviews with a number of craniotomists and their patients over a period of several years, and through observation of a number of the operations. Cultural background, rationale and indications, techniques and instrumentation, complications, and medical implications of this practice are examined. Our findings are recorded to preserve the details of a cultural phenomenon which is probably destined to disappear within this generation.

Craniocerebral Trauma↗
PubMed1985

Composite tissue (limb) allografts in rats. I. Dose-dependent increase in survival with cyclosporine.

The dose-response effect of cyclosporine on rat limb transplant prolongation was investigated across the LBN-to-LEW histocompatibility barrier. This composite tissue allograft model has been shown to represent a strong transplantation barrier. Median limb allograft survival times increased in a dose-dependent manner with low cyclosporine doses, and then reached a plateau at higher levels. The cyclosporine dose that produced half-maximal survival based on a 20-day treatment was only 3.7 mg/kg/day. Histopathology revealed that the rejection process was distinctly different in limb allografts treated with cyclosporine compared with non-cyclosporine-treated controls. Rejection appeared to be delayed or partly arrested in certain areas of cyclosporine-treated limb allografts. These studies represent an initial step in laying the experimental foundation for clinical transplantation of composite tissue allografts using cyclosporine-induced immune suppression.

Animals↗
PubMed1985

Composite tissue (limb) allografts in rats. II. Indefinite survival using low-dose cyclosporine.

Cyclosporine has reawakened interest in transplantation of peripheral composite tissue allografts (CTA) of skin, muscle, bone, vessel, and nerves. The purpose of this study was to examine whether cyclosporine could produce indefinite survival of CTA. Two groups of LEW recipients of LBN limb transplants were given different long-term treatments of cyclosporine. Tolerance was achieved in many of the animals. Several possibilities for the mechanism of this tolerance are discussed.

Animals↗