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Biomedical subjects

G B Snow

Publications and source records attributed to G B Snow.

At least 307 records · Page 17Linked to original sources
PubMed1974

Intra-arterial infusion with methotrexate in the rat.

The superiority of intra-arterial infusion with methotrexate (MTX) over its systemic use in the treatment of head and neck tumours is still being questioned. A model in the rat, suitable for intra-arterial administration of MTX could be constructed. In this model 3 schedules have been investigated: (1) 7 days continuous intra-arterial infusion with MTX; (2) the same schedule combined with leucovorin (CF) 6-hourly intraperitoneally (i.p.) after Sullivan et al. (1959); (3) intermittent administration of MTX 2 × 24 h intra-arterial infusion on Day 1 and 4, while on Day 2, 3, 5, 6 and 7 the catheter is kept open by the continuous intra-arterial infusion of saline. For all the three schedules intra-arterial MTX proved to be superior to its systemic use.

Animals↗
PubMedDate not supplied

Intraoral adenoid cystic carcinoma: the role of postoperative radiotherapy in local control.

Fourteen cases of adenoid cystic carcinoma (ACC) of the intraoral salivary glands with positive surgical margins have been reviewed in order to determine the role of postoperative radiotherapy in local control. Since local control was obtained in all patients, postoperative radiotherapy seems an adequate treatment to deal with the problem of positive surgical margins at the microscopic level, in cases of intraoral ACC, making additional surgical treatment redundant.

Adult↗
PubMedDate not supplied

Preclinical chemotherapy on human head and neck cancer xenografts grown in athymic nude mice.

This study was undertaken to investigate the potential role of xenografts established from human head and neck squamous cell carcinoma (HNSCC) in the selection of new anticancer agents for phase II clinical trials. Eight HNSCC tumor lines were established in NMRI nude mice. The tumor-bearing animals were then treated with drugs at the maximum tolerated dose level. Treatment with drugs known for their activity in 15%-30% of HNSCC patients [cisplatin (CDDP), bleomycin (BLEO), 5-fluorouracil (5-Fu), cyclophosphamide (CY), and doxorubicin (DOX)] caused strong responses in up to 38% and moderate responses in 50%-67% of the HNSCC tumor lines. Methotrexate (MTX), known to cause remissions in about 40% of HNSCC patients, was only minimally active in this model system. A clinically ineffective drug, amsacrine (m-AMSA), was included as a negative control and showed no or minimal activity in all four HNSCC lines tested. A number of experimental drugs that have promising preclinical activity were also tested. Brequinar sodium (Dup 785) and 10-ethyl, 10-deaza-aminopterin (10-EdAM) showed activity in three of five, and two of the four tested tumor lines respectively. N,N-dimethylformamide (DMF) and 5-aza-2'-deoxycytidine (5-aza-dCyd), agents with the capacity to induce differentiation in in vitro systems, showed moderate activity in 43% and 40%, and strong activity in 14% and 40% of the lines, respectively. Our results indicate that the nude mouse xenograft model may play a role in the screening of new drugs, and in particular, it could be of help in the selection of drugs to be tested in phase II HNSCC clinical trials.

Animals↗
PubMedDate not supplied

Mucosal melanomas of the head and neck.

Mucosal melanoma of the head and neck is a rare condition. This study presents a review of 26 patients with such tumors, followed up at a minimum of 5 years. The 5-year survival rate in this group was 38%. Recurrences with a fatal outcome, however, have been encountered up to 12 years after initial diagnosis. Primary radical surgery offers the best chance for local control. Nasal-cavity lesions seem to be associated with a better prognosis than oral-cavity tumors. Analysis of pathologic features by microstage measurement showed that the majority of tumors were of considerable thickness. This factor may partially explain the poor prognosis associated with mucosal melanomas in comparison to their cutaneous counterparts. Local recurrences and distant metastases were the principal causes of treatment failure. A persistent treatment policy, however, may still substantially prolong survival in such cases. Regional lymph-node metastasis did not pose a significant problem in the management of these tumors. Recognition of the nature and significance of the appearance of oral melanosis is stressed.

Adult↗
PubMedDate not supplied

Experiences with the deltopectoral flap in reconstructive surgery of the head and neck.

Despite the development of many alternative methods of reconstruction in head and neck surgery, the deltopectoral skin flap still remains a useful method in our armamentarium. Its use as a nondelayed procedure in 44 patients with various defects in the head and neck following tumor surgery is discussed. The reliability of the deltopectoral flap is evaluated. Major necrosis of the flap occurred in 6 (13.6%) of our patients. As to the cause of failure, more than one factor could be identified in the individual patient. However, the failure rate was higher when the flap was used in the reconstruction of defects in the anterior part of the oral cavity, particularly the floor of the mouth, than at other sites in the head and neck.

Adult↗
PubMedDate not supplied

Vertical partial laryngectomy for recurrent glottic carcinoma after irradiation.

Vertical partial laryngectomy after a full course of irradiation was performed in 26 patients as salvage surgery for recurrent or residual glottic carcinoma. An excellent cure rate and conservation of function was obtained, while complications were few. A prerequisite for this type of surgery is a limited extent and infiltration of the recurrent local tumor growth. As the great majority of local recurrence appears within the first 2 years after radiotherapy, frequent follow-up during this period is stressed for early detection of a recurrence.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Staffieri's procedure revisited.

Our long-term experience with Staffieri's procedure in 42 patients is presented. Our results were evaluated regarding voice production, aspiration problems, and pharyngocutaneous fistula formation. Approximately 50% of the patients were successfully rehabilitated. Twenty-five percent of the patients did not use the neoglottis for speech production, mostly because of stenosis of the neoglottis. The remaining 25% had serious aspiration problems that needed treatment. It was striking that half of these patients initially benefitted from the Staffieri procedure and had no aspiration problems. These 42 patients were compared with a group of 43 patients who underwent conventional total laryngectomy in the same period. After total laryngectomy and Staffieri's procedure, greater than 35% of the patients had a pharyngocutaneous fistula, while after conventional total laryngectomy the fistula rate was less than 20%. The average postoperative stay in the hospital was longer in the Staffieri group. In the long run, the results of this surgical technique do not justify its further use, especially after previous radiotherapy.

Adult↗
PubMedDate not supplied

False-positive and false-negative neck nodes.

We report our experience of the incidence of false-positive (i.e., clinically positive and histologically negative) and false-negative (i.e., clinically negative and histologically positive) neck nodes and define their relationship to the primary site, T-stage, and the histologic grade of the primary lesion. Clinical and pathologic records of 255 patients with squamous cell carcinoma (SCC) of the head and neck who underwent 266 radical neck dissections were reviewed. We did not find any relationship between the T-stage of the primary tumor and the incidence of the false-positive and false-negative neck nodes. Regarding the primary site, the benefit of an elective neck dissection is likely to be maximum in oropharyngeal SCC and minimum in supraglottic SCC. The incidence of false-negative neck nodes was lower in well differentiated primary lesions.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Prevention of second primary cancers in head and neck cancer patients: new perspectives.

Not all head and neck cancer patients have the same chance to develop second primary cancers. New evidence suggests that it is possible to select high-risk patients. Other new developments in Europe are intensive screening, not only during initial work-up but also during follow-up, and chemoprevention of second primaries by retinol and n-acetyl-cystein.

Head and Neck Neoplasms↗
PubMedDate not supplied

MR imaging of laryngeal cancer.

Forty-four consecutive patients with laryngeal carcinomas presenting at different stages of the disease were investigated by magnetic resonance (MR) imaging. Twelve patients (six with primary lesions and six with recurrent tumors) underwent laryngectomy, and the macro- and microscopic appearance of the slice specimens were correlated with MR imaging. In the remaining patients surgery was not performed, and MR results are compared with the laryngoscopic findings. Cancerous tissue was seen on T1-weighted images as a homogeneous mass of intermediate signal intensity. slightly higher than infrahyoid muscles. The MR examinations failed mainly in patients with tumor recurrence who had undergone previous radiation treatment.

Aged↗