Association of adhesive macromolecules with terminal sprouts at the neuromuscular junction after botulinum treatment.

Small quantities of botulinum toxin (BTX) are useful in the treatment of certain movement disorders, such as laryngeal spasmodic dysphonia, blepharospasm, and cervical dystonia. However, the corrective paralytic effects of BTX are only temporary, in part because of the formation of remodeled neuromuscular junctions. Here, we questioned whether various factors within and near the neuromuscular junction could contribute to the remodeling seen after BTX treatment. BTX was injected subcutaneously in the region of the levator auris longus muscle. At 1-week intervals, levator auris longus muscles were removed and examined histochemically. As previously described, BTX treatment results in a progressive elongation of end plates. The neural cell adhesion molecule was not associated with the elongated end plates but was associated with the BTX-induced nerve sprouts after long intervals (3 to 4 weeks). Similarly, after BTX, laminin-1 (composed of alpha 1, beta 1, and gamma 1 chains) reactivity was associated with the nerve sprouts, but not with the end plates. Laminin beta 2 reactivity at the end plate dispersed somewhat within 1 week but remained diffusely associated with the elongating end plates for up to 5 weeks. Together these results suggest that neural cell adhesion molecule and laminins may participate in the sprouting observed after BTX treatment and that alterations in laminin beta 2 expression may participate in initial loss of contacts.

Transnasal illumination to guide the craniofacial resection of anterior skull base neoplasms.

The authors describe use of a flexible fiberoptic light source to guide the craniofacial resection of anterior skull base neoplasms. The light is introduced transnasally and serves to outline the perimeter of the tumor, helping to direct the safe placement of intracranial osteotomies and en bloc tumor removal.

The surgical management of facial syringomas using the superpulsed CO 2 laser.

Syringomas are benign tumors of eccrine origin that occur primarily in the lower eyelid region of females. Since they do not involute and are typically refractory to conventional forms of therapy, they may grow to become considerable, chronic cosmetic and functional deficits. The current study reports on a patient with familial syringomas, previously refractory to two different standard therapies, who was successfully treated with the superpulsed CO 2 laser. A simple, accurate, and reproducible method of dosimetry of laser energy was used to treat these lesions with the Sharplan 700 CO 2 laser connected to the operating microscope. Each lesion was irradiated separately with single pulses at a calculated energy density of 1 J/cm 2. Superficial scabbing was observed 1 week postoperatively, with no edema or pain. Mild erythema persisted for 1 month, with complete healing thereafter. No recurrences were noted after a 2 year follow-up. There was no evidence of scarring, ectropion, or changes in pigmentation. The disease and methods of treatment are reviewed.

Computer-assisted instruction in otolaryngology: the use of a database for examination review.

A database of questions and answers has been developed to assist residents in reviewing current topics in otolaryngology-head and neck surgery. Each question/item has an associated answer, general category, specific category, and reference that allows cross-referencing on the computer system. The user can search the database for categories of interest and obtain a specific subset of questions. This allows an efficient means of knowledge acquisition and review for Board examinations. Additional data entry is also facilitated to expand the database as desired. Currently there are more than 2300 items in the database.

Photodynamic therapy using rhodamine-123 as a new laser dye: biodistribution, metabolism and histology in New Zealand rabbits.

Rhodamine-123 (Rh-123) has been tested recently as a new laser dye for photodynamic therapy of human tumors in vitro and in vivo. Prior to initiation of clinical studies of this technique, we evaluated the biodistribution, metabolism, and pathological changes of Rh-123 in rabbits after systemic, repetitive injections of the dye in escalating doses. At doses between 0.1 to 1 mg/kg of Rh-123 injected intramuscularly (IM) daily for 5 days, no local or systemic toxicity was observed during the 4 weeks of follow-up. The peak concentrations of Rh-123 in micrograms/g of tissue was distributed as follows: kidney (3.24) greater than heart (2.24) greater than spleen (1.77) greater than lung (0.61) greater than liver (0.38) greater than skin (0.30) greater than skeletal muscle (0.17) greater than genitals (0.13) greater than brain (0.04). The elimination of Rh-123 was very rapid, with the dye falling to 2.7% of peak concentration at 72 hours in the kidneys, and to undetectable levels at 240 hours postinjection in all organs, except the skin, which retained 3% of the peak level at 240 hours. The low toxicity and rapid metabolism of Rh-123 in this preclinical model suggests that the dye and Argon laser may represent an effective combination for treatment of superficial malignancies.

Pharyngoesophageal intubation injuries: three case reports.

The hypopharynx and cervical esophagus are particularly vulnerable to intubation trauma. Contributing factors include hasty intubation by inexperienced personnel; the use of curved, beveled endotracheal tubes containing stylets; malpositioning of the head, and the application of cricoid pressure. Iatrogenic pharyngoesophageal perforations may go unsuspected until characteristic signs and symptoms are recognized. These include cervical pain, fever, dysphagia, leukocytosis, subcutaneous emphysema, and pneumomediastinum. We present three cases that illustrate important points in recognizing, evaluating, and treating pharyngoesophageal perforations. The third case presents a chronic cervical esophageal perforation with secondary pseudodiverticulum, requiring resection of the pseudodiverticulum and a primary sternocleidomastoid muscle flap repair of the cervical esophageal defect. To our knowledge, this technique has not previously been reported.

Interstitial laser phototherapy assisted by magnetic resonance imaging: a new technique for monitoring laser-tissue interaction.

The rapid technological advances of magnetic resonance imaging, laser fiberoptics, and compatible probes may allow treatment of deep and sometimes surgically unreachable tumors of the head and neck with minimal morbidity through interstitial laser phototherapy. In this study, a new application of magnetic resonance imaging was developed to monitor and quantify laser-induced tissue damages. Pig skin was exposed to increased levels of argon laser (514.5 nm) at energy densities between 62.5 and 375 J/cm2 as determined by an accurate and reproducible method of dosimetry. Thermal profiles were recorded using an infrared sensor and T1- and T2-weighted magnetic resonance images were taken; afterward, biopsies were performed to quantitate the level of tissue damage. Our results demonstrate that above a certain threshold of laser energy, the magnetic resonance imaging findings are temperature dependent. Appropriate development of a scale matching laser energies, temperature profiles, T1- and T2-weighted magnetic resonance images, and histological quantitation of tissue destruction will allow us to optimize the three-dimensional control and monitoring of laser-tissue interactions.

Rhodamine-123 as a new laser dye: in vivo study of dye effects on murine metabolism, histology and ultrastructure.

Rhodamine-123 (Rh-123) is a mitochondrial-specific dye that has recently proven to be an effective fluorochrome for photo-dynamic therapy of squamous carcinoma cells and melanomas with the Argon laser. Complete eradication of heterotransplanted human tumors in nude mice was possible if tumors were first "sensitized" to Rh-123 and then treated with the Argon laser. Prior to initiation of human testing of this technique, the toxicity and pathological changes in BALB/c mice were tested by an escalating dose schedule after systemic injection of Rh-123. Animals' body weight, blood chemistry, enzymes and organ evaluation for histology, and ultrastructural changes were analyzed for 3 weeks after injection with Rh-123. The results of this study demonstrate that Rh-123 has significant systemic toxicity in BALB/c mice injected at doses of 10 micrograms/g of body weight and above, manifested by chronic weight loss and elevation of muscle enzymes with death of the animals injected at doses higher than 50 micrograms/g of body weight. At doses of 1 micrograms/g of Rh-123, no local or systemic toxicity was observed even after a 3-week follow-up, suggesting that safe and effective tumor sensitization might be possible in humans at this concentration. The high effectiveness of this new technique of photodynamic therapy and the low toxicity of this dye in this preclinical model system suggests that Rh-123 and the Argon laser may represent a powerful new method for treatment of superficial malignancies.