Cationic liposome-enhanced adenoviral gene transfer in a murine head and neck cancer model.

The effect of combining adenoviral vector and cationic liposomes on the efficiency of gene transfer to head and neck tumor cells was investigated. Two human and two murine cell lines were used for the screening of gene transfer efficiency using an adenoviral vector. Cationic liposome-enhanced gene transfer was checked using a murine squamous carcinoma cell line, SCCVII/SF. A considerable difference in the efficiency of gene transduction was observed among the cell lines. The combination of DOSPER and adenoviral vector containing human alkaline phosphatase showed a remarkable enhancing effect in gene transfer in vitro and in vivo, compared to the adenovirus alone or control groups. With an improvement in the efficiency of gene transfer, it may be possible not only to enhance the expression of transduced genes, but also to deliver a smaller amount of virus, as a result, reducing toxicity and the immune response against adenovirus.

Pyriform sinus fistula: management with chemocauterization of the internal opening.

A branchial remnant originating in the pyriform sinus causes a recurrent fistula or abscess in the neck. In spite of excision, recurrence may result from inadequate removal of the fistula tract. We attempted chemocauterization of the internal opening of the fistula tract with trichloroacetic acid (TCA) on direct endoscopy. This is a 6-year review of 18 patients with pyriform sinus fistula. Medical history, barium esophagography, computed tomography scans, operative findings, and treatment results were analyzed. By direct endoscopy, all patients were found to have a fistula opening in the pyriform sinus, exclusively on the left side. In only 9 patients, the fistula tract was identified by barium esophagography before operation. Computed tomography revealed a suspicious fistula tract originating from the pyriform sinus in 8 of 10 patients. Sixteen patients were initially managed by TCA chemocauterization. There were no serious intraoperative or postoperative complications. Four patients had recurrent masses, which were managed by simple excision in 2 patients and repeated TCA cauterization in the other 2 patients with unobliterated internal openings. We recommend barium swallow study and direct endoscopy for all patients presenting with a recurrent lateral neck abscess, especially on the left side. Our results suggest that initial chemocauterization of the internal opening can be a reasonable alternative procedure for the management of pyriform sinus fistula.

Videostrobokymography: a new method for the quantitative analysis of vocal fold vibration.

OBJECTIVES: To develop a new analysis method for the quantitative assessment of vibration of the vocal folds, using conventional videostroboscopic image data. METHODS: We used prerecorded videostroboscopic images to evaluate quantitatively the vibration of the vocal folds. Successive images were converted as digital images by means of an image-grabbing board, processed for analysis, and reconstructed as kymograms by rearranging the same lines of all processed images along the time axis. RESULTS: We developed a new technique for evaluating the vibration of the vocal folds. The vibrations of multiple vocal fold regions were easily and objectively evaluated by this technique. The objective parameters, such as open quotient and asymmetry index, could be obtained easily using this technique. CONCLUSIONS: Videostrobokymography demonstrated objectively the vibrations of several vocal fold regions at the same time. This technique has the potential to be a new tool to analyze and monitor the pathological changes and treatment results of vocal fold movement in a more refined quantitative fashion, using videostroboscopic images.

Neoadjuvant chemotherapy and radiotherapy for the treatment of advanced hypopharyngeal carcinoma.

PURPOSE: To evaluate the efficacy of the neoadjuvant chemotherapy and radiation therapy in treatment of patients with advanced hypopharyngeal cancer, which is notorious for its poor prognosis and severe surgical morbidity with functional deficits. MATERIALS AND METHODS: Medical records of 62 patients with squamous cell carcinoma of the hypopharynx, Stage III or IV (AJCC, 1992), were retrospectively reviewed. RESULTS: Neoadjuvant chemotherapy showed an overall response rate of 87% and a complete remission (CR) rate was 67% following chemotherapy and radiation therapy. The patients who did not show CR after chemotherapy had a high likelihood of treatment failure, even though they achieved CR following subsequent radiotherapy. Thirteen of 30 patients were able to preserve their larynges for more than 3 years by chemotherapy and radiation. CONCLUSION: This approach appeared to be as effective as radical surgery with postoperative radiation therapy without comprising survival. To improve the cure rates, we need to develop better strategies to increase CR rates with chemotherapy and determine the best treatment option for patients who are partially or nonresponsive to chemotherapy.

Surgical management of congenital aural atresia.

Congenital aural atresia is a relatively common anomaly in otology. It requires an early assessment of hearing status and an early evaluation of the degree of atresia. Its surgical management is aimed at obtaining hearing gain and at establishing appropriate auditory canal status for the application of hearing aids. The authors analyzed the preoperative otologic findings, surgical findings, postoperative complications, and postoperative hearing results of 25 ears in 21 patients with congenital aural atresia. From January 1987 to February 1992, 24 of these ears were surgically corrected by anterior approach; the remaining 1 was corrected by transmastoid approach. Postoperative audiologic follow-up ranged from 8 months to 4 years (N = 21). A new modification of anterior approach is introduced. The final average air-bone gap was 30 dB, in contrast to preoperative 53 dB (N = 21). The final air-bone gap was improved to a level within 30 dB in 52% of the patients. Meatal stenosis was the most frequent postoperative complication and was seen in 12 patients in primary operation (N = 25). There was no postoperative facial nerve palsy and no sensorineural hearing loss. There was little difference in postoperative hearing among the various types of congenital aural atresia and the type of tympanoplasty that had been performed.

Growth characteristics and polyene sensitivity of a fatty acid auxotroph of Candida albicans.

A fatty acid auxotroph of Candida albicans 6406, designated A' 44 and originally isolated as an oleic acid requiring strain, has been shown to be a delta9 desaturase mutant. Although lacking this step in fatty acid biosynthesis, it appears to retain the ability to desaturate monounsaturated fatty acids. The polyene sensitivity of the organism grown on different fatty acid supplements varied between 0-08 +/- 0-02 and 1-20 +/- 0-30 microgram amphotericin B methyl ester ml-1 for exponentially growing cells. In spite of this variation, the sterol composition remained fairly constant, the major differences lying in fatty acid composition. Stationary-phase cells were more resistant to amphotericin B methyl ester, although again this change was not associated with changes in sterol content. The organism was most resistant when grown in the presence of oleic or linoleic acid. Protoplasts derived from resistant organisms grown on these two fatty acids were also resistant, indicating that the structure of the cell wall was less important than that of the plasma membrane in determining polyene sensitivity under these conditions.

The interaction of amphotericin B methyl ester with protoplasts of Candida albicans.

The interaction of amphotericin B methyl ester (AME) with protoplasts of Candida albicans was measured indirectly by following the incorporation of [U-14C]phenylalanine into the acid-insoluble material. The inhibitory effects of AME at the minimum inhibitory concentration were prevented by the addition of 85 mM-KCl and 45 mM-MgCl2, as shown by Liras & Lampen (1974) for Saccharomyces cerevisiae. In C. albicans, pretreatment of the yeast before anti-biotic addition was unnecessary. KCl and MgCl2 did not prevent AME from binding to the protoplast membrane. This interaction was reversed by incubating the protoplasts in the presence of the protecting salts.

Structure and function of immunoglobulin domains. V. Binding, University of immunoglobulin G and fragments to placental membrane preparations.

Fc receptors have been shown to be present in human placental tissue with properties distinct from those on macrophages and lymphocytes. A single class of receptor was observed with an intrinsic affinity 4X 10(6) M-(1) for human IgG1. The order of affinity for IgG subclasses was IgG1 = IGG1 greater than IgG3 greater than IgG4. IgA and IgM were not bound. Fc from IgG1 bound with the same affinity as the whole molecule and to the same number of receptor sites, 2 X 10 (12)/mg placental protein. IgG1 was no longer boung after mild reduction and alkylation whereas the binding of Fc was unaffected by this treatment. Neithe C3 nor C3, the two domains which comprise the Fc region of IgG1, bound to the placental receptor. This implies that this Fc receptor is unlike those found on most cell surfaces and that plasental binding is an exception to the theory that each domain has evoked to perform independent functions.

Studies on the 'osmophilic' yeast saccharomyces rouxii and an obligate osmophilic mutant.

An obilagte osmophilic mutant (strain BI/4) of Saccharomyces rouxii has been isolated that fails to grow at osmotic pressures corresponding to 20 per cent (w/v) sucrose or less. In 30 percent sucrose the yeast is filamentous and grows slowly. In 40percent sucrose it is mainly filamentous and has over twice the normal diameter. In 60 percentsucrose it grows in the yeast form with a growth rate twic that of the cultrue in 40 per cent sucrose. This mutant is lysed by a suddren drop in the osmotic pressure of the environment. Cell enveoples of the parent strain contained glucose and manose in the ratio I.2; Iand contained 3-8percent (w/v) hexosamine, whereas the envelopes of the mutatn contained 0-8 percent hexosaime. Cell envelopes of the mutant grown in 40 per cent sucrose contained glucose and mannose in the ratioI.9; I, wheras for envelopes of the yeast grown in 60 percent sucrose the ratio was I.2; I. Neutral lipids from whole cells and those from the envelopes of the mutant strain generally contained more unsaturated fatty acids than the corresponding fractions from the parent strain.

Factors affecting the changes in amphotericin sensitivity of Candida albicans during growth.

The sensitivity of Candida albicans, grown in batch culture at 37 degrees C, to amphotericin methyl ester (AME), judged by the concentration of AME required to induce a standard rate of leakage of K+ from suspensions of organisms, decreased with the time of growth. Organisms in exponential growth were sensitive to 0-I to 0-2 mug AME/ml while organisms in the stationary phase were resistant to 4 to 60 mug AME/ml, depending on the initial concentration of glucose in the medium and the length of time for which incubation had been continued. When the initial concentration of glucose was low (0-I%, w/v), the AME resistance rose during the early stationary phase and then, after 40 h incubation at 37 degrees C, decrease again. Sphaeroplasts were prepared from organisms at different phases of growth and did not show these changes in AME sensitivity, but remained highly sensitive for growth up to 40 h. Sphaeroplasts were prepared by treating suspensions of organisms with mercaptoethanol and then digesting with Streptomyces enzyme preparation. Addition of the material extracted by the digestion to suspensions of exponential-phase organisms or sphaeroplasts increased their AME resistance. Fractionation of the digest showed that the antagonistic material was contained in the neutral lipid fraction. Pure lipids fell into the following order of decreasing antagonism to AME when added together with the antibiotic to suspensions of exponential-phase organisms: sterol esters (ergosterol esters greater than cholesterol esters; unsaturated fatty acid esters greater than saturated fatty acid esters), sterols, triglycerides, unsaturated fatty acids, saturated fatty acids. The amount of antagonistic material released from stationary organisms was not markedly greater than that from exponential-phase organisms and analysis of the lipid content of wall preparations showed that the content of total lipid, neutral lipid and triglyceride of 40 h organisms was not more than 75, 25 and 30%, respectively, greater than that of exponential-phase organisms. The AME resistance of stationary-phase organisms decreased rapidly if suspensions were incubated with glucose or mercaptoethanol. The decrease in the presence of glucose was prevented by metabolic inhibitors, especially SH binding agents. Treatment of organisms with either iodoacetamide or N-ethylmaleimide gave a rapid increase in AME resistance, amounting in some cases to 5- to 15-fold. The effect of iodoacetamide decreased as the organisms passed into the stationary phase and their intrinsic resistance increased. Evidence is presented which suggests that the degree of reduction of SH groups in the cell surface is an important factor in determining AME resistance.