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Biomedical subjects

J B Boyd

Publications and source records attributed to J B Boyd.

At least 73 records · Page 4Linked to original sources
PubMed1989

An evaluation of the pedicled thoracoumbilical flap in upper extremity reconstruction.

A pedicled thoracoumbilical flap was evaluated in 5 patients for upper limb reconstruction. The flap appears to be a reliable axial flap that can be elevated safely to the midaxillary line. It has the capacity to transfer a large amount of tissue, allowing the damaged limb, during the attached period, to be elevated and to receive physiotherapy. Although the working portion of the flap uses the thin, hairless skin over the lateral ribs, the base of the flap is thick and difficult to tube in all but the thinnest of individuals. The donor scar is much more conspicuous than that of a groin flap.

Arm Injuries↗
PubMed1989

Orofacial and mandibular reconstruction with the iliac crest free flap: a review of 60 cases and a new method of classification.

Sixty vascularized iliac crest free-tissue transfers were used for oromandibular reconstruction, 46 as osteocutaneous and 14 as osseous flaps. Forty-one patients had preoperative radiotherapy, and 8 had failed previous attempts at reconstruction. Forty-nine of the 60 reconstructions were carried out primarily, most commonly following ablative surgery for radiorecurrent squamous carcinoma. Ages ranged from 19 to 85 years, and follow-up ranged from 2 months to 5 years. Flap survival was 95 percent. Eight-six percent of patients returned to their previous activities. There were 2 perioperative deaths, and 31 patients were alive at follow-up. Horizontal defects from 5 to 16 cm were reconstructed, and in 22 patients, both oral lining and skin coverage were replaced. Radiographic evidence of bone union was noted in 96 percent of synostoses, and clinical union was seen in all but one patient. One patient required bilateral hemimandibular reconstructions for sequential primaries at different operative sittings. Functional and cosmetic results were generally satisfactory and were excellent in bone-only reconstructions. Several surgical principles evolved to minimize bulk and eliminate the need for intermaxillary fixation or external fixation postoperatively. To improve results in large or more lateral through-and-through defects, an accessory pectoralis musculocutaneous flap proved advantageous. Cosmetic and functional results depend largely on three factors: the extent of the surgery, the leanness of the patient, and his or her position on the surgical learning curve.

Adult↗
PubMed1988

The nasolabial flap. Axial or random?

Considerable confusion exists regarding the nature of the blood supply of the inferiorly based nasolabial flap. This report seeks to clarify the situation. Anatomic dissections were performed on 12 cadaveric specimens and microangiography on six others. We confirmed that the facial artery passes deep to the facial mimetic muscles and is not normally included within the flap. Although the vasculature of the flap is technically random, the small vessels of the subdermal plexus are generally oriented along its long axis giving it a "degree of axiality." We believe this vascular orientation is responsible for the flap's reliability.

Angiography↗
PubMed1988

Mandibular reconstruction in the young adult using free vascularized iliac crest.

Five young adults between the ages of 16 and 27 years underwent mandibular reconstruction with free vascularized iliac crest bone grafts based on the deep circumflex iliac artery. These were the only patients under age 30 years in a series of over 60 patients undergoing this procedure. In all cases, the ipsilateral crest was employed, and special efforts were made to minimize bony bulk by removing the outer cortex and carefully shaping the graft. The bone graft underwent final trimming in situ, the exact dimensions being reproduced from measurements taken from the excised specimen. When bone alone requires replacement, as in the majority of young patients, an excellent functional result can be anticipated. Occlusion can be maintained or even restored, and the normal facial contour can be re-established. Osteointegrated implants hold out the possibility of providing full dental rehabilitation in an age group in which anything less is considered failure. Furthermore, the donor site scar can be hidden by a bathing suit. It is concluded that this form of reconstruction is particularly suitable for the young adult, in whom cosmesis, function, donor site, and freedom from long-term complications are of supreme importance.

Adenocarcinoma↗
PubMed1988

Gracilis muscle repair of rectovaginal fistula after restorative proctocolectomy. Report of two cases.

Gracilis muscle interposition flaps have been used to treat two patients with rectovaginal fistulas. The fistulas occurred following restorative proctocolectomy with a J-shaped ileal reservoir and ileoanal anastomosis. Attempts at local repair of the fistulas had failed. A diverting loop ileostomy was constructed simultaneously. Anterior sphincteroplasty was performed in one patient for associated incontinence. Excellent results were achieved in both patients. The fistulas have healed, and intestinal continuity has been re-established. This procedure can be useful to salvage a pelvic pouch complicated by a rectovaginal fistula.

Adult↗
PubMed1987

Pyrimidine dimers in Drosophila chromatin become increasingly accessible after irradiation.

A prokaryotic DNA-repair enzyme has been utilized as a probe for changes in the accessibility of pyrimidine dimers in Drosophila chromatin following UV irradiation. The results demonstrate a rapid cellular response to physiologically relevant doses of radiation which results in at least a 40% increase in accessible dimers. This increase occurs in two incision-deficient mutants which indicates that the excision-repair process, at or beyond the incision step, is not required or responsible for the increase. In the absence of excision the increase in accessibility persists for at least 2 days following irradiation. The observed increase in accessibility is inhibited by both novobiocin and coumermycin. These inhibitors do not inhibit the initial rate of incision, but do reduce dimer excision measured over more extended periods. A pre-incision process is proposed which actively exposes DNA lesions to excision repair. A fraction of the genome is postulated to be accessible without the intervention of that process.

Animals↗
PubMed1987

Extensive pharyngo-oesophageal reconstruction using multiple jejunal loops.

Two patients underwent subtotal pharyngo-oesophageal reconstruction using jejunum transferred by means of microvascular anastomosis. In both cases, two sets of vascular anastomoses were required, one in the lower neck and the other at the mid-sternal level. In the first patient, a continuous length of jejunum was employed but this led to great redundancy of the bowel on account of coiling as a result of its mesenteric attachment. In the second case, two isolated loops were employed with minimal redundancy. An anatomical study on three fresh cadavers indicated that the maximum defect which can be bridged by a single loop of jejunum lies between 15 and 20 cm. No particular part of the jejunum or ileum seems particularly advantageous in terms of its ability to span large defects.

Adult↗
PubMed1987

Bilateral functional mandibular reconstruction using the iliac crest free flap. A case report.

A patient who developed multiple metachronous primary carcinomas of the oval cavity is presented. After initial radiation therapy, a right hemimandibulectomy was required, followed ten months later by a left hemimandibulectomy. Immediate reconstruction of each defect was performed with a free vascularized iliac crest osteocutaneous flap. Using this flap, both bony continuity and intraoral lining were successfully restored. The patient was able to return rapidly to his previous activities. The results of this case suggest that preservation of the mandibular condyle for lateral fixation of the bone graft is superior to disarticulation of the temporomandibular joint in terms of cosmetic and functional outcomes.

Carcinoma, Squamous Cell↗
PubMed1987

Isolation and characterization of a photorepair-deficient mutant in Drosophila melanogaster.

A mutation abolishing photorepair has been localized to map position 56.8 centimorgans on the second chromosome of Drosophila melanogaster. Strains homozygous for the phr allele are totally devoid of photorepair and partially deficient in excision repair. Both defects map to the chromosomal region between pr and c. Since a homozygous phr stock exhibits reduced photoreactivation, the corresponding wild-type allele plays a significant role in UV resistance.

Animals↗
PubMed1987

Severe perifolliculitis capitis with osteomyelitis.

This report describes a severe case of perifolliculitis capitis with the rare complication of skull osteomyelitis, a combination not previously reported. The patient demonstrated the typical features of perifolliculitis capitis, namely, rubbery, hard, elevated nodules involving almost the entire scalp with multiple deep-seated abscesses. Bone was exposed in two areas and the diagnosis of skull osteomyelitis was confirmed by skull x-ray films and bone biopsy specimens, which grew Staphylococcus aureus. The patient was treated with enteral hyperalimentation, intravenous antibiotics, and multiple debridements of the scalp, including the involved periosteum and outer cortex of the exposed bone, followed by reconstruction with split-thickness skin grafts. A complete eradication of the disease with closure of all open wounds and clearance of osteomyelitis of the skull was achieved.

Adult↗
PubMed1987

Tissue expansion in reconstruction.

Tissue expansion offers a new alternative in plastic surgery. Its applications are numerous for reconstruction of the scalp, head and neck, trunk, breast, and extremity. Over the past year I have used tissue expansion for reconstruction in 13 patients, with multiple expanders in six patients. Complications included two exposed expanders requiring early removal, and two mechanical malfunctions requiring replacement. Expansion of previously irradiated tissue has been unsatisfactory.

Abdominal Muscles↗
PubMed1987

Free jejunal grafts in pharyngoesophageal reconstruction.

The free jejunal graft with microvascular anastomosis offers the head and neck surgeon a reliable, single-stage method of repair for small cervical defects and also for more extensive pharyngoesophageal defects where one or more loops of jejunum can successfully be used. If microvascular expertise is available, this method of reconstruction offers early alimentary rehabilitation and a physiologic repair. The free jejunal graft is a reliable method of reconstruction not only after failed gastric pull-up or when that procedure is not feasible, but also, where the facilities exist, as a primary method of pharyngoesophageal reconstruction.

Adult↗
PubMed1986

Cytogenetic characterization of the 4BC region on the X chromosome of Drosophila melanogaster: localization of the mei-9, norpA and omb genes.

Thirty genetic alterations, which involve the 4BC region of the Drosophila X chromosome, have been induced by ionizing radiation or by an endogenous mutator element. These mutations were recovered by screening for reversion of the dominant mutants Oce and Qd or for induction of the recessive mutants bi and rb. Among the 23 mutants generated by ionizing radiation, 20 have proven to be cytologically detectable chromosomal aberrations. Seven additional unique aberrations were generated in the Uc mutator strain. In total, 22 cytologically detectable deficiencies, 3 translocations, 1 inversion, 1 transposition, and 3 cytologically normal mutants have been recovered. Complementation analysis has permitted the cytogenetic localization of eight genes in the 4BC region. The mei-9 locus has been assigned to region 4B4-6, because this function is carried by Df(1)rb41 but not by Df(1)biD1. The norpA locus has been placed in the 4B6-C1 region based on its location between the distal breakpoints of Df(1)biD2 and Df(1)rb41. The genes lac, Qd, bi, and omb are localized to bands 4C5,6, rb to 4C6 and amb to 4C7,8. With one exception the complementation analysis has also permitted a determination of the linear sequence of these genes. This cytogenetic localization of these loci will facilitate the cloning and molecular analysis of genes controlling a key function in DNA repair and recombination (mei-9), and two fundamental neural functions (norpA and omb).

Alleles↗
PubMed1986

Hypersensitivity of Drosophila mei-41 mutants to hydroxyurea is associated with reduced mitotic chromosome stability.

6 mutant alleles of the mei-41 locus in Drosophila melanogaster are shown to cause hypersensitivity to hydroxyurea in larvae. The strength of that sensitivity is directly correlated with the influence of the mutant alleles on meiosis in that: alleles exhibiting a strong meiotic effect (mei-41D2, mei-41D5, mei-41D7) are highly sensitive; alleles with negligible meiotic effects (mei-41(104)D1, mei-41(104)D2) are moderately sensitive and an allele which expresses meiotic effects only under restricted conditions (mei-41D9) has an intermediate sensitivity. This sensitivity is not a general feature of strong postreplication repair-deficient mutants, because mutants with that phenotype from other loci do not exhibit sensitivity (mus(2)205A1, mus(3)302D1, mus(3)310D1). The observed lethality is not due to hypersensitivity of DNA synthesis in mei-41 larvae to hydroxyurea as assayed by tritiated thymidine incorporation. Lethality is, however, potentially attributable to an abnormal enhancement of chromosomal aberrations by hydroxyurea in mutant mei-41 larvae. Both in vivo and in vitro exposure of neuroblast cells to hydroxyurea results in an increase in 3 types of aberrations which is several fold higher in mei-41 tissue. Since hydroxyurea disrupts DNA synthesis, these results further implicate the mei-41 locus in DNA metabolism and provide an additional tool for an elucidation of its function. The possible existence of additional genes of this nature is suggested by a more modest sensitivity to hydroxyurea which has been detected in two stocks carrying mutagen-sensitive alleles of alternate genes.

Animals↗