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Biomedical subjects

D J Hoyt

Publications and source records attributed to D J Hoyt.

10 recordsLinked to original sources

Treating ankylosed primary teeth in adult patients: a case report.

When ankylosed primary teeth are retained beyond the mixed-dentition stage and the involved teeth are below the occlusal plane, occlusal and interproximal contacts can be restored to esthetic and functional anatomic contours. With the development of new, improved posterior composite resins that have greater wear resistance and stronger adhesive bonding systems for enamel and dentin, new opportunities for conservative, simple, and efficient esthetic and functional restorations are possible in selected retained ankylosed primary molars.

Acrylates↗

The effect of head and neck radiation therapy on voice quality.

Twenty-five patients with squamous cell carcinoma of the head and neck who received radiation therapy as their only form of treatment underwent a computer-assisted voice analysis before, and 6 months following treatment. Those with early laryngeal tumors had a significant improvement in intelligibility (P = .07), percent of sound voiced (P = .04), and sound perturbation. Those with nonlaryngeal tumors had no change in any measured parameters. Head and neck radiation therapy can significantly improve the voice quality of patients with laryngeal tumors, while having a minimal effect on the voice quality of those with nonlaryngeal tumors.

Carcinoma, Squamous Cell↗

Otolaryngologic management of patients with subdural empyema.

From 1979 to 1988, 17 patients presented to Duke University Medical Center for treatment of subdural empyema. Empyemas were caused by sinusitis in 53% of the patients and by otitis media in 12%. None of those with otologic causes required mastoid drainage, while all patients with sinus infections required sinus drainage. External frontoethmoidectomies were associated with a lower incidence of frontoethmoid re-exploration (P = 0.048), and antrostomies with a lower incidence of maxillary re-exploration (P = 0.111), than were more limited drainage procedures. Sinus drainage performed simultaneously with neurosurgical drainage reduced the incidence of sinus re-exploration (P = 0.167), neurosurgical reexploration (P = 0.048), and length of hospitalization (P = 0.020).

Adolescent↗

Mucosal melanoma of the head and neck.

From 1972 to 1988, 15 patients presented to the Duke University Melanoma Clinic, Durham, NC, with malignant melanoma of the mucus membranes of the upper aerodigestive tract. Eleven patients had a nasopharyngeal origin of their melanoma, while 4 patients had oropharyngeal lesions. The average age of the patients was 58.4 years. Median survival for the patients was 1.8 years, with a 5-year survival of approximately 10%. Survival was found to be independent of sex, tumor site, and extent of disease at presentation. Recurrence occurred in 80% of the patients and the median time to recurrence was 10 months. The median survival following recurrence was 13 months and was independent of the site of recurrence. Mucosal melanoma of the head and neck continues to result in a poor prognosis in spite of aggressive treatment.

Adult↗

Survival following recurrent malignant melanoma of the head and neck.

A retrospective analysis of 877 patients who had malignant melanoma of the head and neck identified 366 patients who developed recurrent disease. Sex, race, age, histology, Clark level, thickness, ulceration, lymph node status, lymph node dissection, site of recurrence, and time to recurrence were analyzed to determine their effect on survival following the development of recurrent disease. Survival following the development of recurrence was found to be influenced by the site of first recurrence and the age of the patient at the time of recurrence. For a given age, patients who had initial recurrences at distant sites were three times as likely to die following recurrence than patients with local recurrence. Patients who had initial recurrences at distant sites were twice as likely to die following recurrence than patients with regional sites of recurrence (p less than 0.001).

Adult↗

On-line detection of reversible myocardial ischemic injury by measurement of myocardial electrical impedance.

The metabolic and physiological alterations associated with changes in myocardial tissue electrical resistivity during ischemia were characterized to assess the feasibility of using such resistivity as an on-line indicator of the onset of ischemic injury. Twelve anesthetized dogs underwent rapid cardiac extirpation; 5 served as untreated controls, and 7 were pretreated with metoprolol tartrate. Beta blockade was used to alter the time course of ischemic injury as demonstrated previously in studies using this experimental model. In vitro measurement of myocardial resistivity, the detection of ischemic contracture, and serial measurements of tissue adenosine triphosphate (ATP) and lactate were obtained from totally ischemic left ventricles at 37 degrees C. Myocardial resistivity began to increase significantly before onset of ischemic contracture in the untreated control group (resistivity at 42.3 +/- 3.1 minutes, contracture at 53.8 +/- 3.7 minutes; p less than 0.025) as well as the metoprolol group (resistivity at 50.7 +/- 1.5 minutes, contracture at 70.0 +/- 3.5 minutes; p less than 0.005). As expected, ischemic contracture was delayed in the beta-blocked group compared with controls (p less than 0.01). Similarly, the onset of myocardial resistivity increase was delayed in the beta-blocked group (p less than 0.025). ATP and lactate levels at the onset of myocardial resistivity increase were consistent with severe but reversible injury. Resistivity changes during ischemia correlated linearly with simultaneous ATP depletion and lactate accumulation (r = 0.88 to 0.98; p less than 0.05). Furthermore, during global ischemia studied in 3 anesthetized dogs in vivo, the onset of myocardial resistivity increase occurred after 20 minutes. Finally, 6 anesthetized dogs underwent 60 minutes of in vivo regional ischemia by coronary artery occlusion, followed by 60 minutes of reperfusion. Myocardial resistivity in the ischemic region increased immediately and steadily after coronary occlusion, followed by a rapid decrease during subsequent reperfusion. These data show that myocardial resistivity may be useful for identifying severe but still reversible ischemic injury in on-line fashion during regional and global myocardial ischemia.

Adenosine Triphosphate↗

Free jejunal interposition graft for reconstruction of the esophagus.

Forty-seven patients underwent pharyngoesophageal reconstruction using a free jejunal interposition graft (FJIG) at Duke University Medical Center from 1978 through 1987. There were 30 men and 17 women with ages ranging from 38 to 87 years old (mean age, 64 years). Twenty-one patients (group A) had no prior surgical procedures, 20 (group B) were reconstructed following radiation and/or surgical failure, with 6 patients (group C) having benign strictures of the upper alimentary tract. Follow-up ranged up to 122 months (mean, 23 months), with 3 patients lost to follow-up, and 4 perioperative deaths (within 3 months of surgery). There were a total of 9 initial graft failures, 4 patients undergoing successful re-implantation, resulting in an overall success rate of 89% (42 of 47). Excluding patients with graft failures, perioperative deaths, and patients lost to follow-up, 33 of 36 patients with a viable FJIG were able to maintain adequate swallowing function yielding a physiologic success rate of 86%. All of the 21 patients dying of recurrent disease had excellent palliation with the FJIG. Of the 7 patients who are alive, only 1 has dysphagia secondary to stricture. In conclusion, it is felt that the FJIG is a sophisticated method of reconstructing large surgical defects of the pharyngoesophagus with a high technical and physiologic success rate.

Adult↗

Retrofitting an esthetic post and core to salvage a six-unit fixed partial denture.

Teeth restored with post and core restorations present a clinical dilemma if they fracture. An individual with a maxillary anterior six-unit fixed partial denture had one of the canine abutment teeth fracture. The other abutment debonded and the post separated from the core. The fixed partial denture was salvaged by retrofitting a porcelain-fused-to-metal post and core restoration in the fractured abutment.

Cuspid↗