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Biomedical subjects

G B Snow

Publications and source records attributed to G B Snow.

At least 199 records · Page 11Linked to original sources
PubMed1991

Occult metastatic neck disease: detection with US and US-guided fine-needle aspiration cytology.

The authors performed a prospective study of the value of ultrasonography (US) and US-guided fine-needle aspiration cytology (FNAC) for assessment of N0 lesions in the neck. Preoperative US was performed in 107 patients with squamous cell carcinoma of the head and neck, who underwent 132 elective neck dissections. During the US examination of the last 54 patients, who underwent 70 elective neck dissections, US-guided FNAC was performed. US alone was found to be an unreliable method for detecting occult lymph node metastasis; the accuracy never exceeded 70% (93 of 132), with a sensitivity of 60% (32 of 53) and a specificity of 77% (61 of 79). In contrast, US-guided FNAC had an accuracy of 89% (62 of 70), a sensitivity of 76% (25 of 33), and a specificity of 100% (37 of 37). Because of the high sensitivity and specificity of US-guided FNAC for the assessment of the N0 neck, this modality may play an important role in directing treatment of these patients in the future.

Biopsy, Needle↗
PubMed1991

[Ameloblastoma: a review].

A review of the ameloblastoma of the jaws is presented. The epidemiology and classification are dealt with, followed by a description of the clinical, radiographic, histopathologic and therapeutic aspects. The paper is partly based partly on personal experience and partly on data from the literature.

Aged↗
PubMed1990

Intraoral adenoid cystic carcinoma. The presence of perineural spread in relation to site, size, local extension, and metastatic spread in 22 cases.

Twenty-two patients with an intraoral adenoid cystic carcinoma (ACC), initially treated by surgery with or without postoperative radiotherapy, were examined for the presence of perineural spread in relation to primary site, size, local extension, histologic status of the surgical margins, and metastatic spread of the tumor. There seems to be no correlation between perineural spread and the primary site or size of the tumor. However, perineural spread occurred more often in tumors with local extension and in cases with surgical margins with positive results. There seems to be no statistically significant correlation between perineural invasion and distant metastatic disease.

Adult↗
PubMed1990

Identification of a 43-kDa nuclear antigen associated with proliferation by monoclonal antibody K 112.

Monoclonal antibody (MAb) K 112 was generated after a single intrasplenic immunization with a recurrent laryngeal squamous-cell carcinoma. The antibody detects a 43-kDa nuclear antigen, with a pI of 5.4, which is expressed only in cycling cells. Expression is typically seen in a granular pattern excluding the nucleoli. During mitosis the bulk of the antigen is diffusely distributed in the cytoplasm. Identical reactivity was observed for tissues or cells of all mammalian species tested. These data indicate that MAb K 112 recognizes a protein belonging to the class of cell-cycle-related nuclear antigen molecules.

Animals↗
PubMed1990

Production of monoclonal antibodies to squamous cell carcinoma antigens.

For therapeutic or diagnostic use of monoclonal antibodies in clinical oncology, high-affinity IgG antibodies to tumor-associated antigens have to be generated. In order to find out by what immunization schedule the chance to generate such antibodies is increased, we evaluated three different immunization protocols with and without attempts to induce tolerance to common tissue antigens. Mice were immunized either (1) by repeated intraperitoneal injections, (2) by a single intrasplenic injection, or (3) by an intraperitoneal injection followed by an intrasplenic booster. Whereas a single intrasplenic immunization resulted in low-affinity antibodies to tumor-associated antigen, high-affinity antibodies were generated with the other two protocols, although at a lower frequency. No benefit was seen from tolerance induction. The intraperitoneal/intrasplenic protocol was found to be superior over the other protocols because of minimal antigen dose and immunization time, as well as a higher frequency of hybridoma formation.

Animals↗
PubMed1990

Relationships of vitamins A and E and beta-carotene serum levels to head and neck cancer patients with and without second primary tumors.

Second primary tumors constitute one of the most challenging problems in head and neck cancer. Their etiology is not yet fully understood. For this reason, we studied the relationships of vitamins A and E and beta-carotene serum levels in patients with head and neck cancer with and without second primary tumors. The results indicate lowered levels of beta-carotene in both groups of patients, while the levels of vitamin A and vitamin E were statistically significantly lower in patients with second tumors than in the group with a single head and neck cancer. This suggests that low vitamin A and vitamin E levels may play a role in the etiology of second tumors in head and neck cancer patients.

Carcinoma, Squamous Cell↗
PubMed1990

Immunosuppressive retroviral-related factors in sera of patients with head and neck cancer.

The chemotactic responsiveness of mononuclear phagocytes has often been found defective in patients with various malignancies. We have previously reported a defective chemotactic responsiveness in patients with head and neck cancer. Low-molecular-weight factors (LMWFs) have been isolated from tumors and can be held responsible for the inhibitory effect on monocyte chemotactic responsiveness. It is an intriguing new finding that these LMWFs can be neutralized by antibodies reactive to P15E, a structural envelope protein of murine leukemia retroviruses. In this report we describe a relatively easy and rapid method for the detection of immunosuppressive P15E-like factors in the sera of patients with head and neck cancer. The test is based on the monocyte polarization assay. Although only nine head and neck cancer patients were included in this study, the findings indicate that the test might be of value for clinical application. An early detection of a recurrence after treatment might be possible by the finding of a reappearance of the P15E-like factors in patients' sera during follow-up.

Aged↗
PubMed1990

Antitumor activity of brequinar sodium (Dup-785) against human head and neck squamous cell carcinoma xenografts.

The effect of Brequinar sodium on the growth of xenografts established from head and neck squamous cell carcinomas (HNSCC) was assessed. Brequinar sodium is a novel drug, known to inhibit dihydroorotic acid dehydrogenase (DHO-DH), resulting in a decrease of the pyrimidine de novo synthesis. The drug was administered i.p. to tumor-bearing nude mice, once a day, during 5 days at a maximum tolerated dose of 50 mg/kg/day. Statistically significant growth delaying effects were observed in 4 out of 5 lines tested. In 3 of these lines the effect was moderate and short lasting, whereas in one line (HNX-LP) tumor growth rate was totally inhibited for a 17-day period. In this line, Brequinar sodium was superior to 5 drugs known to be active in HNSCC patients. In two tumor lines DHO-DH activity could be measured and the results are in agreement with the concept that there is a relation between Brequinar sodium sensitivity and enzyme activity.

Animals↗
PubMed1990

Blindness: a potential complication of bilateral neck dissection.

Permanent blindness, is a very rare, but devastating complication of simultaneous bilateral neck dissection. Most otolaryngologists/head and neck surgeons are unaware that amaurosis can result from this surgery, and this paper is meant as a poignant reminder of that end. A case report is presented, followed by a discussion of possible aetiology; a management protocol is proposed.

Blindness↗
PubMed1990

Production of a monoclonal antibody (K 931) to a squamous cell carcinoma associated antigen identified as the 17-1A antigen.

During our efforts to develop monoclonal antibodies (MAbs) to tumor associated surface antigens of squamous cell carcinomas of the head and neck, monoclonal antibody K 931 was produced. The high affinity antibody (Ka 5.0 x 10(10) M-1) showed reactivity with 58 out of 62 squamous cell carcinomas of the head and neck. In contrast normal squamous epithelium as found in epidermis, oral cavity, epiglottis, pharynx, larynx and esophagus did not express the antigen. All other tested epithelial (simple and transitional) tissues did express the antigen, but non-epithelial tissues were negative. Further characterization revealed that the antigen represents the 17-1A antigen. A not earlier reported, enhanced expression of the 17-1A antigen was observed among some primary and all metastatic SCC.

Animals↗
PubMed1990

MR findings of cartilage invasion by laryngeal cancer: value in predicting outcome of radiation therapy.

Thirty-nine patients who underwent radiation therapy with curative intent for laryngeal cancer were examined before treatment with magnetic resonance (MR) imaging, between November 1985 and January 1987. MR findings of cartilage invasion were correlated with the effectiveness of radiation treatment. Adequate interpretation of the MR examinations was not possible in four cases (10%). Cartilage invasion was found in 16 of the 35 remaining patients and was found even in small glottic lesions, clinically staged as T1b and T2. Laryngeal cancer recurred in 10 of the 16 patients with cartilage invasion shown by MR imaging. The presence of even small foci of invasion of the thyroid cartilage by laryngeal cancer appeared to increase the subsequent risk of tumor recurrence. Cartilage invasion seen at MR imaging might therefore shift the preference to partial laryngectomy as the initial treatment for small glottic tumors. Alternatively, radiation therapy alone would appear to require stringent follow-up to detect possible recurrence.

Adult↗
PubMed1990

Cervical lymph node metastasis: assessment of radiologic criteria.

To estimate the accuracy of different radiologic criteria used to detect cervical lymph node metastasis in patients with head and neck carcinoma, seven different characteristics of 2,719 lymph nodes in 71 neck dissection specimens from 55 patients were assessed. Three lymph node diameters, their location, their number, the presence of a tumor, and the amount of necrosis and fatty metaplasia were recorded. The minimal diameter in the axial plane was found to be the most accurate size criterion for predicting lymph node metastasis. A minimal axial diameter of 10 mm was determined to be the most effective size criterion. The size criterion for lymph nodes in the subdigastric region was 1 mm larger (11 mm). Groups of three or more borderline nodes were proved to increase the sensitivity but did not significantly decrease the specificity. Radiologically detectable necrosis (3 mm or larger) was found only in tumorous nodes and was present in 74% of the positive neck dissection specimens. Shape was not a valuable criterion for the radiologic assessment of the cervical lymph node status.

Carcinoma, Squamous Cell↗
PubMed1990

Comparative study of the sensitivity of head and neck cell lines to methotrexate (MTX) and the analog 10-ethyl, 10-deazaaminopterin (10-EdAM).

Squamous cell lines cultured in vitro provide a potential test system for the selection of analogs that have an improved therapeutic index. The growth inhibitory effects of methotrexate and the new folate analog 10-ethyl, 10-deazaaminopterin were compared in three in vitro-cultured human head and neck squamous cell carcinoma cell lines. The inhibitory concentrations of the new analog were 10- to 100-fold lower than the inhibitory concentrations of methotrexate. The sensitivity of these three head and neck squamous cell carcinoma cell lines to both drugs was essentially the same as the sensitivity of a rhabdomyosarcoma cell line known to be very sensitive to methotrexate when the cell line is grown as a xenograft in athymic nude mice. These data indicate that 10-ethyl, 10-deazaaminopterin may be a new and effective agent against head and neck squamous cell carcinoma.

Aminopterin↗
PubMed1990

The efficacy of comprehensive neck dissection with or without postoperative radiotherapy in nodal metastases of squamous cell carcinoma of the upper respiratory and digestive tracts.

Neck recurrence-free curves corrected for local recurrence were compared for 494 patients who underwent 565 comprehensive neck dissections. In 42 dissections, no radicality could be obtained. Of the 523 histologically radical dissections, examination revealed tumor in 352 cases. Patients in whom three or more positive nodes or extranodal spread in one or more nodes were found received postoperative radiotherapy. In the histologically N0 group, the incidence of neck recurrence after 5 years was 3%; in the N+ group as a whole, it was 10%. Analysis of the influence of extranodal spread and the number of positive nodes showed that the group with one or two positive nodes without extranodal spread (that did not receive postoperative radiotherapy) did not statistically differ from the other groups. This suggests that the results of the group with one or two positive nodes without extranodal spread can be improved by postoperative radiotherapy.

Adult↗
PubMed1990

[(Chemo-) prevention of second tumors in patients with head and neck neoplasms].

This review discusses the possible role of chemoprevention in the improvement of survival rates and the prevention of secondary primary tumours in patients with head and neck cancer. Chemoprevention is a new treatment that is especially promising for high risk groups. The fear that the advantages of this treatment will be outweighed by the disadvantages of side-effects and toxicity has not been confirmed by current studies. Randomized studies are needed to show whether chemoprevention can reduce the frequency of second primary tumours.

Carotenoids↗