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Biomedical subjects

S B Boyd

Publications and source records attributed to S B Boyd.

11 recordsLinked to original sources
PubMed1995

Accelerated fractionation radiotherapy and concomitant chemotherapy in patients with stage IV inoperable head and neck cancer.

BACKGROUND: Stage IV inoperable head and neck cancer has a 2-year mortality rate of greater than 70% when treated with conventional radiotherapy. A Phase II study was undertaken to evaluate the effects of concomitant chemotherapy and accelerated, interrupted, twice-a-day radiotherapy on tumor response, locoregional control, survival, and morbidity. METHODS: Thirty-four patients with Stage IV inoperable squamous cell carcinoma of the head and neck and a minimum follow-up of 36 months were evaluated. Concomitant chemoradiotherapy was administered during weeks 1, 3, and 5 (with planned breaks during weeks 2 and 4), consisting of cisplatin 60 mg/m2 on day 1, continuous 5-day infusion of 5-fluorouracil, 750 mg/m2 per day, and radiotherapy, 2 Gy twice a day, more than 6 hours apart, followed by 3 days of radiation therapy alone (final "boost") in week 6, for a total dose of 70 Gy and treatment duration of 5 1/2 weeks (38 days). RESULTS: Twenty-seven patients achieved a clinical complete response (82%). Actuarial locoregional control at 3 years was 73% and the actuarial 3-year survival probability, including all deaths, was 38%. All locoregional recurrences were manifested within 12 months. Of the 20 deaths, 12 were tumor related (locoregional and/or metastatic), 3 were treatment related, and 5 were due to other causes. Acute toxicity consisted of grade 3 mucositis and dysphagia and grade 2-3 leukopenia, not requiring treatment interruption or cessation. CONCLUSION: Concomitant accelerated radiation therapy and chemotherapy is a feasible treatment approach in this prognostically poor patient population, yielding dramatic tumor responses and impressive locoregional control at the cost of somewhat increased acute toxicity. Although serious late complications have not been observed, caution should be exercised in view of the relatively short follow up.

Adult↗
PubMed1995

Primary craniofacial chordoma: case report.

A 37-year-old man presented with right facial pain and a nonpalpable mass over the malar eminence. An incisional biopsy via the intraoral route was performed and interpreted as a vascular malformation with degenerative changes. His symptoms persisted, and a repeat biopsy was suggestive of an epithelioid nerve sheath tumor. Total resection of the tumor was planned to include the infraorbital and malar regions, the infratemporal fossa, and the pterygopalatine fossa. At surgery, the tumor was removed with tumor-free margins obtained along the course of the maxillary nerve just before its entrance into the cavernous sinus. The pathological findings and the immunohistochemistry demonstrated a typical chordoma with no chondroid or sarcomatous dedifferentiation. We think that with greater use of immunohistochemical markers and electron microscopy, patients with chordoma in this location may be diagnosed promptly and accurately.

Adult↗
PubMed1991

Retrospective analysis of low-velocity gunshot wounds to the mandible.

A retrospective study was conducted of 32 patients with mandibular fractures resulting from low-velocity gunshot injuries. Airway management was required in 25% of the patients, and 9% sustained major vessel injury. Patients were divided into two groups, depending on site of mandibular fracture: condyle, ramus, and coronoid (n = 10), and angle, body, and symphysis (n = 22). All patients in the condyle, ramus, coronoid group achieved clinical union without infection. Average postinjury maximal mandibular opening was restricted (28 mm), but the average follow-up period was relatively short (2 months). In the angle, body, symphysis group the infection rate was 27%, and in 18% of patients a continuity defect of the mandible developed. The average length of follow-up in this group was 5.4 months with a mean maximal mandibular opening of 36 mm.

Adolescent↗
PubMed1991

Recovery of mandibular mobility following orthognathic surgery.

The aim of this prospective study was to define the patterns of recovery of mandibular mobility following three commonly performed orthognathic surgical procedures. Twenty-two consecutive patients undergoing either isolated Le Fort I osteotomy (LE FORT; n = 7), sagittal split ramus osteotomies (SSRO; n = 7), or intraoral vertical ramus osteotomies (IVRO; n = 9) were studied. LE FORT and SSRO patients had no mandibular immobilization, whereas IVRO patients were immobilized by dental fixation for 3 weeks. Mandibular mobility was assessed by measurement of maximal mandibular opening (MMO) and lateral and protrusive excursions. No significant difference in MMO was observed between groups prior to surgery (LE FORT, 47.0 mm; SSRO, 50.7 mm; IVRO, 54.5 mm). A significant reduction in MMO occurred immediately after surgery in the LE FORT and SSRO groups and at release of fixation in the IVRO group. Each group returned to presurgical levels of mandibular mobility at a different rate following surgery. LE FORT patients recovered quickly, regaining 83% (mean, 38.7 mm) of MMO by 1 month and exceeded preoperative levels (mean, 49.6 mm) by 6 months. SSRO patients showed hypomobility (mean, 23.5 mm) after 1 month, with significant improvement in MMO (mean, 38.0 mm) at 2 months, and nearly complete recovery (96.2%; mean, 48.8 mm) at 6 months. IVRO patients recovered rapidly after release of dental fixation, achieving 78% (mean, 39.8 mm) of preoperative MMO at 2 months. This study shows that significant differences in recovery patterns of mandibular mobility exist between surgical procedures. The clinician should be aware of these differences in recovery patterns in defining goals for individual patient rehabilitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Muscle activity patterns and control of temporomandibular joint loads.

The strategy used by the neuromuscular system to distribute reaction forces to the temporomandibular joints on the working and balancing sides has not been fully defined. Theoretical studies and experimental measurements suggest that the two joints are unevenly loaded during unilateral biting or closures for posterior teeth. However, previous electromyographic studies suggest that muscle activity patterns may attempt to balance the distribution of the two joint forces. This study measured bilateral activity in the anterior temporal, posterior temporal, and superficial masseter muscles during isometric bites or closures and chewing at five different positions along the teeth. The resulting ratios of muscle activity on the working/balancing sides were compared with ratios required to maintain equal joint forces. The values of the muscle activity were also used to estimate the ratio of joint forces on the working/balancing side at each tooth position. Results indicate that the muscle activity patterns do not maintain equal joint forces, nor are the muscles responding to joint forces exceeding critical limits. These results suggest that patterns of muscle activity are designed to control the position and magnitude of occlusal forces rather than temporomandibular joint forces. If these same patterns of activity are maintained following repositioning of dental and skeletal elements, adverse temporomandibular joint forces could result.

Adult↗
PubMed1990

Recovery of neurosensory function following orthognathic surgery.

The purpose of this study was to prospectively define the recovery of touch discrimination following four commonly performed surgical procedures in 22 consecutive patients with no previous maxillofacial surgery. The surgical groups studied were Le Fort I osteotomy (LEFORT; n = 13), sagittal split ramus osteotomy (SSRO; n = 6), intraoral vertical ramus osteotomy (IVRO; n = 9), and isolated genioplasty (GENIO; n = 5). Neurosensory function was assessed by three different testing modalities which included static light touch (SLT), moving touch discrimination (MTD), and two-point discrimination (TPD). Cutaneous sensation of the lower lip and chin were examined for the mandibular procedures, whereas the infraorbital and upper lip regions were evaluated following maxillary surgery. Immediately following surgery, each group varied in both the incidence and magnitude of neurosensory deficits (NSD). The SSRO group had the highest percentage of sites with immediate postsurgical NSD to both SLT (72%) and MTD (67%), followed by the LEFORT (SLT = 50%, MDT = 58%), GENIO (SLT = 27%, MTD = 6%), and IVRO groups (SLT = 11%, MTD = 18%), respectively. Each group also varied in the severity of the initial postoperative deficit as measured by SLT, with the SSRO group showing the greatest deficit followed by the LEFORT, GENIO, and IVRO groups. During the 6-month recovery period each group approached preoperative levels of sensation at a different rate. The LEFORT group recovered most rapidly, with few anatomic sites showing NSD (SLT = 20%, MTD = 5%) at the 1-month postoperative examination, and the majority of the group (96%) returned to preoperative sensation by 3 months following surgery. The SSRO group recovered more slowly, with approximately half of the group demonstrating a deficit (SLT = 50%, MTD = 59%) at 1 month, which diminished to about one fourth of the sites (SLT = 25%, MTD = 5%) by 3 months. Most of the SSRO group (90%) exhibited no residual deficit 6 months following surgery. The IVRO group had few sites with immediate NSD (SLT = 11%, MTD = 15%). In none of the surgical groups was a statistically significant correlation found between the severity of the initial NSD and length of time to complete recovery.

Adolescent↗
PubMed1990

Hereditary hyperparathyroidism and multiple ossifying jaw fibromas: a clinically and genetically distinct syndrome.

A large previously reported family with hyperparathyroidism has been reinvestigated recently because of the occurrence of multiple ossifying jaw fibromas in two affected members of the third generation similar to the jaw tumors of four of five affected members of the first generation. These maxillary and mandibular tumors can be differentiated from the "brown tumors" of hyperparathyroidism because they can appear and enlarge even though the hypercalcemia is surgically corrected. These tumors are histologically distinct fibroosseous lesions without the giant cells seen in "brown tumors." The parathyroid enlargement was mostly uniglandular, with multiple tumors found occasionally. Studies in DNA linkage were performed within this large family and a similar family in Houston to determine if the gene for this syndrome, termed HRPT2, is linked to DNA markers on chromosome 11, to which the gene for multiple endocrine neoplasia (MEN) type 1 has been linked. (This linkage is supported by our findings in one family with MEN 1 reported here.) Linkage studies were also performed with markers on chromosome 10, to which the genes for MEN 2A and MEN 2B have been linked. Evidence against close linkage with chromosome 10 and chromosome 11 markers suggests that this clinically distinct syndrome is also genetically distinct.

Female↗
PubMed1989

Masseter muscle adaptation following surgical correction of vertical maxillary excess.

This study was designed to examine the adaptive response of the human masseter muscle following surgical correction of abnormal facial form. Biopsies of the deep surface of the anterior superficial masseter muscle were obtained from five patients demonstrating vertical maxillary excess (VME), one at the time of corrective surgery, and a second at a long-term postoperative time interval (mean, 8 months). Control biopsies were also obtained from five individuals (three cadavers and two patients) with normal dentofacial morphology. A standard regimen of histologic and histochemical staining was used to classify individual muscle fibers as either type 1, type 2, or intermediate. In both VME patients and normal subjects type 1 fibers predominated, with the control group displaying a higher percentage (50% vs. 43%). On the average, type 1 fibers also had the largest areas. Following surgery there was an increase in type 2 fibers (30% vs. 52%). Two patients receiving maxillary surgery only exhibited either no change in mean fiber area or only a slight increase. The three remaining patients who underwent concomitant maxillary and mandibular surgery all showed a significant decrease in mean fiber area. Two persons in the latter group also showed features consistent with a denervation-reinnervation process. The results of this study indicate that the human masseter responds to surgical manipulation of the jaws in a histochemically demonstrable manner, with the nature and magnitude of the response associated with the particular surgical procedure(s) performed.

Adaptation, Physiological↗
PubMed1984

Histochemical study of the masseter muscle in patients with vertical maxillary excess.

This study was designed to examine the morphologic properties of the masseter muscle in individuals with vertical maxillary excess (VME). The deep surface of the anterior aspect of the superficial masseter was biopsied in nine patients at the time of corrective surgery. Individual muscle fibers were classified as slow-twitch-oxidative (SO), fast-twitch-oxidative-glycolytic (FOG), or fast-twitch-glycolytic (FG) based on staining characteristics using a battery of histochemical procedures. Most patients had normal tissue, although there were considerable differences in size and distribution of the three fiber types. Generally, SO fibers were the largest and most prevalent type of fiber. Two individuals, however, demonstrated evidence of muscle pathology that primarily affected the FG fiber population. Histochemical evidence of muscle pathology has not previously been reported in patients with VME, and the pattern of SO dominance observed in these patients may be different from the distribution that would be seen in the masseter of a person free of craniofacial deformities.

Adenosine Triphosphatases↗
PubMed1975

A classroom program teaching disadvantaged youths to write biographic information.

Little attention has been given to how formal classroom instruction can be adapted to teach youths everyday skills such as the correct writing of biographic information frequently requested in transactions like applying for a job or a social security number and cashing a check. In this study, six youths in a special education classroom were taught to complete job application forms with the date, their name, signature, address, telephone number, date of birth, and a reference's name, address, and occupation. Each youth was trained on one item of biographic information at a time, after which he was tested on four application forms, including one on which he had not been trained. The tests show that after an item had been taught, it was correctly used in completing application forms on which the youths had been trained and forms on which they had never been trained. The study demonstrates the feasibility of teaching community-living, vocation-related skills to special-education youths in a classroom setting.

Journal Article↗