Design and manufacture of all-dielectric nonpolarizing beam splitters.

Past research on all-dielectric nonpolarizing beam splitters is reviewed. It is shown that, for a 50-nm spectral region, it is possible to design and manufacture a two-material nonpolarizing plate beam splitter for use at an angle of 45 degrees (with a measured rms reflectance of 0.50 +/- 0.01 for both s- and p-polarized incident light).

Optimal treatment of descending necrotising mediastinitis.

BACKGROUND: Descending necrotising mediastinitis is caused by downward spread of neck infection and has a high fatality rate of 31%. The seriousness of this infection is caused by the absence of barriers in the contiguous fascial planes of neck and mediastinum. METHODS: The recent successful treatment of seven adult patients with descending necrotising mediastinitis emphasises the importance of optimal early drainage of both neck and mediastinum and prolonged antibiotic therapy. The case is also presented of a child with descending necrotising mediastinitis, demonstrating the rapidity with which the infection can develop and lead to death. Twenty four case reports and 12 series of adult patients with descending necrotising mediastinitis published since 1970 were reviewed with meta-analysis. In each case of confirmed descending necrotising mediastinitis the method of surgical drainage (cervical, mediastinal, or none) and the survival outcome (discharge home or death) were noted. The chi 2 test of statistical significance was used to detect a difference between cases treated with cervical drainage alone and cases where mediastinal drainage was added. RESULTS: Cervical drainage alone was often insufficient to control the infection with a fatality rate of 47% compared with 19% when mediastinal drainage was added (p < 0.05). CONCLUSIONS: Early combined drainage with neck and chest incisions, together with broad spectrum intravenous antibiotics, should be considered standard care for this disease.

Doxorubicin plus metronidazole in the treatment of recurrent or metastatic squamous cell carcinoma of the head and neck.

Twenty-five patients were treated on a Phase II study of doxorubicin, 60-75 mg/m2 intravenously every 3 weeks, accompanied by metronidazole, 1500 mg/m2 orally 12 hours and immediately before the doxorubicin and 6 hours and 24 hours after the doxorubicin. Of 23 patients evaluable for response, 2 (9%) achieved complete remissions, 2 (9%) achieved partial remissions, and 4 (18%) were stable (one of whom achieved a minor response). One patient with an inoperable biopsy-proven 4 x 3 x 3 cm recurrence following radiation and surgery has had a complete remission that persists at 8 years. The second patient who achieved a complete remission subsequently underwent surgical resection of the involved area. No residual tumor was found, and he remains disease free after 8.5 years. Doxorubicin toxicity did not appear to be augmented significantly by metronidazole. Although the response rate seen in this study was low, the occurrence of two long-term complete remissions suggests that this combination should be studied further in other tumor types.

Cisplatin, cytosine arabinoside, and pentoxifylline in the treatment of squamous cell carcinoma of the head and neck.

Nine patients were entered on a Phase I-II study of cisplatin, cytosine arabinoside, and pentoxifylline in the treatment of advanced head and neck cancer. The treatment regimen consisted of cisplatin 100 mg/m2 intravenously on day 1 only, cytosine arabinoside 2,000 mg/m2 intravenously on days 1 and 2, and pentoxifylline 400 mg orally three times daily beginning 7 to 14 days before the chemotherapy. The pentoxifylline was continued between chemotherapy cycles. Chemotherapy courses were repeated at 3- to 4-week intervals. Partial remission were seen in two patients, two patients were stable, and five patients failed on treatment. Dose-limiting toxicity was granulocytopenia. Pentoxifylline itself caused some nausea and anorexia. Although the patient numbers were small, there was no indication that pentoxifylline increased the efficacy of this chemotherapy in head and neck cancer. It is possible that another dose schedule might have been more effective.

Human auditory steady state responses: effects of intensity and frequency.

Human auditory steady state responses were recorded in 41 normal subjects and 22 patients with hearing loss. The effect of intensity on the responses at different tonal frequencies was assessed using the sweep technique. The amplitude of the responses increases and the phase delay decreases with increasing intensity. Both the amplitude and the phase delay are smaller for high frequency tone bursts. Notched noise decreases the amplitude of the response by a factor of two but does not affect the phase of the responses. Thresholds were estimated in waking subjects using two techniques: intensity sweeps analyzed by linear regressions, and fixed intensities analyzed by Hotelling's T2 test. Frequency-specific thresholds obtained with notched noise were less variable and more accurate with the fixed intensity technique. In patients with sensorineural hearing loss the amplitude increased more with increasing intensity above threshold than in patients with conductive hearing loss.

Cisplatin plus cytosine arabinoside in the treatment of squamous cell carcinoma of the head and neck.

Twenty-seven patients with squamous cell carcinoma of the head and neck were treated with i.v. cisplatin 50-100 mg/m2 followed by a rapid infusion of cytosine arabinoside 500-4,000 mg/m2. All except four of the patients had received prior irradiation and six had had prior chemotherapy. There was one early death. Of 25 evaluable patients, one (4%) achieved a complete remission and 10 (40%) achieved partial remissions lasting 6-50 weeks (median, 16 weeks). Ten patients (40%) were classified as having stable disease, including five (20%) who experienced minor responses lasting 5-8 weeks. Four patients (16%) had progressive disease. Drug doses, patient performance status, and prior exposure to chemotherapy did not appear to alter the response rate. Gastrointestinal toxicity was severe in some patients. Myelosuppression tended to be unpredictable and variable within individual patients and was not clearly related to drug doses. Two patients had generalized seizures and one became confused while hypomagnesemic. Renal toxicity, ototoxicity, and paresthesias were seen only at a cisplatin dose of 100 mg/m2. One patient developed stomatitis and one had an allergic reaction to cisplatin. There was one possible drug-related death. This regimen is reasonably well tolerated and may be somewhat more active than cisplatin alone, although further studies are needed to confirm it. Further studies involving additional doses of high dose cytosine arabinoside following cisplatin could also be worthwhile.

Methotrexate and 5-fluorouracil in the treatment of squamous and other carcinomas of the head and neck.

Thirty-two patients with squamous cell carcinomas of the head and neck and three patients with parotid gland carcinomas were treated with methotrexate 40 mg/m2 followed 1 h later by 5-fluorouracil 600 mg/m2. Treatments were repeated on day 8, then every 2 weeks, toxicity permitting. Of 30 evaluable patients with squamous cell carcinomas, 9 (30%) achieved a partial (8) or complete (1) remission. Performance status and prior treatment history appeared to affect the probability of response. The original site of the primary had no apparent effect on response rate. Six patients having objective tumor regression but less than the amount required for classification as partial remission all had marked symptomatic relief and had "response" durations and survivals quite comparable to those in patients achieving partial remission. One patient with a parotid gland carcinoma attained a complete remission, one had a minor response, and one refused to return for follow-up. Myelosuppression and stomatitis were dose-limiting in some patients, although the regimen was generally well tolerated. Three patients (9%) developed cerebellar toxicity, suggesting that prior ethanol abuse could possibly predispose to this side effect.