A comparison of the shear strength of chemically versus electrolytically etched metal retainers

The recent popularity of acid-etched, resin-bonded retainers (RBR) has initiated improvements in design, technique, and etching. This study compared the shear strength of chemically etched Biobond retainers with electrolytically etched retainers bonded to enamel using identical cement. Shear fracture loads were recorded using Instrom testing for all specimens. The mean fracture load for the electrolytically etched castings was greater than that of the chemically etched castings. Electrolytically etched specimens also recorded the greatest and the least fracture load values. These results indicated that, while there were significant differences between the two groups with greater shear strength values for electrolytic etching, there was also more variation in shear fracture load with electrolytic etching.

Risk of viral hepatitis among military personnel assigned to US Navy ships

A prevalence study of 2072 male US shipboard military personnel scheduled for deployment to South America/West Africa and the Mediterranean was conducted to determine whether serologic evidence of prior hepatitis A, B, or C infection is associated with exposure in foreign countries. There were 210 subjects (10.1%) who had antibodies to hepatitis A virus (anti-HAV), 76 (3.7%) to hepatitis B core antigen (anti-HBc), and 9 (0.4%) to hepatitis C virus (anti-HCV). By multivariate analysis, anti-HAV seropositivity was independently associated with age, non-white racial/ethnic groups, birth outside of the United States, and prior Caribbean deployment for less than 1 year. Anti-HBc seropositivity was independently associated with black and Filipino race/ethnicity, foreign birth, a history of a sexually transmitted disease, South Pacific/Indian Ocean deployment (less than 12 months), and South Pacific or Mediterranean duty for (greater than 1 year). No geographic risk factors were associated with anti-HCV positivity. These data indicate that military personnel deployed outside the United States are at increased risk of viral hepatitis infection and should be considered for vaccination.

The effect of staff stress on patient behavior

A "natural experiment" examined the effects of staff turmoil caused by personal and group issues during and after the merger of two formerly separate neuropsychiatric evaluation units, on patient acting-out behaviors. Interviews with staff members identified the periods of high staff stress, and then two periods of personal resolution (3 to 4 months after the merger) and group reconstitution (8 to 12 months later). Patient acting-out behaviors (1:1 supervision, length of time on 1:1, use of the quiet room, seclusion, and restraints) tended to peak at times of staff peace. Behaviors under patient control (72-hour notices and discharges against medical advice) were also frequent during these periods, but showed additional activity in the time between personal and organizational resolution. While the relationship between staff issues and patient behavior is by no means straightforward, analysis of quantitative and qualitative data gathered here provides some support to the "reverse hypothesis" that when staff are upset, patients will not act out and vice versa. Implications for management, clinical practice, and research are presented.

Single-stage laryngotracheal reconstruction

The mainstay for repairing subglottic and tracheal stenosis has been the rib graft with prolonged stenting. A refinement of this treatment was the use of the anterior cricoid decompression (split). We present single-stage reconstruction of the airway as an additional refinement of the laryngotracheoplasty. This article describes the experience of two institutions with single-stage reconstruction and offers some observations on the principles of the technique.

Manual and oral praxis in adults with Down's syndrome

Mentally handicapped adults with and without Down's syndrome performed single movements and movement sequences following both verbal and demonstration cueing conditions. While the type of cue did not influence the performance of control subjects, Down's syndrome individuals exhibited more error following verbal cueing. These findings could not be explained on the basis of verbal encoding differences between the groups. The results support the notion that Down's syndrome persons suffer from a dissociation of the functional system responsible for speech perception and the system involved with the organization of complex movement.

New laryngeal surgery may improve voice

Laryngeal framework surgery has increased the options the otolaryngologists have available to treat voice disorders ranging from unilateral vocal cord paralysis to pitch disorders.

Phonosurgery: indications and pitfalls

Twenty-five patients underwent type 1 thyroplasty (external medialization of abducted true vocal cord) during a 2-year period 1986 to 1988) at the University of Iowa. The most common indication for thyroplasty was post-thyroidectomy vocal cord paralysis. Eighteen patients (72%) had either a good or an excellent initial result. Five patients were revised. Postrevision, 21 patients (84%) had achieved either a good or an excellent result. Complications were limited to one case of significant vocal cord edema and another instance of vocal cord hemorrhage. No patient required a tracheotomy. No prosthesis extruded. We feel that phonosurgery has the advantages over traditional Teflon injection of allowing the patient's head to be in a neutral position during the operation; of allowing local anesthesia; of permitting a predictable, graduated end point of the procedure; and of being infinitely adjustable, with preservation of the vocal cord mucosal wave.

Pediatric liver transplantation: a 3-year experience

From September 1, 1984 to March 1, 1988, 201 patients were evaluated for liver transplantation. Ninety-one orthotopic liver transplants were performed on 80 children ranging in age from 3 months to 15 years. The average waiting time for a transplant was 5 months, with children less than 10 kg in weight waiting a disproportionately long time. The average operative time was 10.6 hours and the average blood product replacement was 2.7 blood volumes. There was a steady improvement in both operative time and blood loss from 1985 to 1987. The overall hepatic arterial thrombosis rate was 9%; complex reconstructions having a thrombosis rate of 39%, and end-to-end anastomoses having a thrombosis rate of 1.4%. The average hospital stay was 37 days, and the major causes of postoperative morbidity and mortality were rejection (75%), infection (50%), and diarrhea (76%). The 1- and 3-year survival rates were 75% and 73%, respectively. Children with a successful transplant returned to home and school. After transplantation, 60% of the children exhibited catch-up growth and 88% have normal liver function. Pediatric liver transplantation is an effective modality in the treatment of children with terminal liver disease. Increased pediatric organ donation and the investigation of new operative techniques and types of preservation are necessary to meet the needs of an expanding recipient pool.

Nonshivering thermogenesis and brown fat in spontaneously hypertensive rats

Oxygen consumption was measured before and during infusion of the catecholamine isoproterenol in age-matched spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) normotensive rats. Mass-independent rates of oxygen consumption of anesthetized 7-week-old rats were similar in the WKY and SHR rats (11.08 +/- 0.74 and 11.33 +/- 0.82 ml O2 min-1 kg-.67, respectively). Catecholamine infusion elicited increased total oxygen consumption in both WKY and SHR animals (15.0 +/- 1.0 and 14.9 +/- 1.2 ml O2 min-1 kg-.67, respectively), and the magnitude of these increases did not significantly differ. To assess whether there were changes in the metabolic state of brown adipose tissue, the major site of catecholamine-induced thermogenesis in rats, enzymes whose activity is proportional to aerobic capacity were assayed in vitro. In both the interscapular and cervical brown fat depots, maximal citrate synthase and maximal HOAD (beta-hydroxyacyl-CoA dehydrogenase) activities were similar in SHR and WKY rats. There were also no significant differences in brown fat protein content, suggesting no differential growth of this tissue in the two rat strains. Our results indicate that the nonshivering thermogenic capacity of the hypertensive SHR rats does not differ from that of the normotensive WKY animals.

Histologic investigation of hyperphonated canine vocal cords

Vocal cord injury and its effect on the larynx are topics of considerable importance, yet a clear understanding of acute vocal cord injury from excessive phonation remains elusive. The inability to develop an animal model for vocal abuse has hampered research in this area. This project describes the development of a canine model for acute vocal cord injury from excessive phonation. The method of phonation consisted of a humidified, temperature-controlled, constant flow of air delivered subglottally by an external compressor. A small group of dogs underwent phonation for 2 and 4 hours. Vocal cord injury is described using histologic techniques. Damage to the vocal cords, other than hemorrhage (rare in dogs) and edema, proved to be too elusive for routine microscopy. Scanning and transmission electron microscopy showed extensive surface damage with destruction and loss of the surface microridges and premature desquamation of the vocal cord squamous epithelium. Injury extended to the lamina propria, where the collagen fibers were detached from the basement membrane.

Nasal presentation of an intracranial vascular anomaly

Intracranial vascular anomalies uncommonly present as a nasal mass. We report the first documented intranasal extension of a venous angioma of the anterior and middle cranial fossas. The diagnostic evaluation and differential diagnosis of an intranasal vascular mass is emphasized. In addition, recommendations are offered regarding the surgical approach of such a lesion.

Otolaryngologic manifestations of chronic granulomatous disease

Patients with chronic granulomatous disease (CGD) have a greatly increased incidence of infection, particularly in the region of the head and neck. For this reason the health care team treating the patient with CGD often includes an otolaryngologist. Because the disease process is associated with an altered host defense mechanism, standard medical and surgical plans must often be modified. In this paper, a representative case is presented illustrating the symptoms, clinical course, and therapeutic regimen of a typical patient. The necessity for aggressive treatment is emphasized.

Adjunctive measures for successful laryngotracheal reconstruction

The field of reconstructive surgery of the laryngotracheal complex has been the object of considerable enthusiasm in recent years. New surgical techniques, better surgical tools, and improved diagnostic skills all have contributed to a more confident approach to severe laryngotracheal stenosis. Just as the surgeon's judgment is crucial for a successful primary laryngotracheal reconstruction, so are his or her skill and judgment vitally important in managing the various problems that frequently are found following reconstructive surgery of the larynx and trachea. These problems, although seemingly minor, may prevent successful decannulation if not managed appropriately. This paper discusses the various problems that have been encountered while achieving decannulation following laryngotracheal reconstruction. An approach to such frustrating problems as suprastomal collapse, granulation tissue, and the inability to decannulate are presented.

Dexamethasone suppression test in depression: association with duration of illness

Plasma cortisol response to 1 mg dexamethasone suppression test was investigated in 37 patients with primary major depressive illness. Non-suppression of plasma cortisol was found in 14 of 37 (38%) patients. Duration of the index episode of illness was significantly shorter in the non-suppressors (11.1 +/- 9.1 weeks) than in the suppressors (29.7 +/- 25.6 weeks). The two groups were not distinguished by age, sex, polarity or severity of depressive symptoms. Eighty per cent of the non-suppressors (4/5) and 57% of the suppressors (8/14) had severe life events or major difficulties in the 6 months preceding the onset of illness, but this difference failed to reach statistical significance.

Strapping of joints

Strapping with adhesive tape plays a significant part in the prevention of joint injuries, particularly at the ankle and hand, and is important during early management of injury and rehabilitation. Recurrence of injury when the athlete recommences training is less likely when supportive strapping is applied.