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Biomedical subjects

G B Snow

Publications and source records attributed to G B Snow.

At least 253 records · Page 14Linked to original sources
PubMed1986

Multiple primary tumors in patients with laryngeal squamous cell hyperplasia.

We analyzed retrospectively the case histories of 204 patients with squamous cell hyperplasia of the larynx for the occurrence of multiple primary tumors. All patients were grouped according to Kleinsasser's 1963 classification of laryngeal pathology. Patients with simple hyperplasia (class I) had a low risk for developing a coincidental primary tumor. The rist was 7% in patients with hyperplasia with atypia (class II) and was 15% in patients with carcinoma in situ (class III). This frequency is similar to that of our patients with glottic cancer (13%). Although no coincidental tumors were found in our female patients, the small number of females in our series made the differences in frequency between males and females not significant. This is still of interest to us because our previous study of patients with proven glottic cancers also showed that no second tumors occurred in our female patients. This difference was statistically significant. In our present study, all second tumors occurred metachronously. Our findings indicate that all patients with class III laryngeal disease (carcinoma in situ) should undergo the same aggressive search for second primary tumors, as do patients with invasive glottic cancers. This means that panendoscopy or bronchoscopy should be done at the initial work-up and also at periodic intervals during the follow-up period. We have also found that patients lacking immunoglobulin allotype Km(1) have to be followed aggressively, since these patients are at high risk of developing multiple tumors. A possible exception can be made for female patients.

Carcinoma in Situ↗
PubMed1986

Multiple primary tumours in oral cancer.

In 210 cases of oral cancer, 38 (17.6%) second primary tumours were found. Males had a higher chance of developing a second primary than females (21.4% versus 12%). The difference was not statistically significant (p = 0.11). When the index tumour was in the lower part of the oral cavity (floor of mouth, retromolar trigone, inferior alveolar process), a higher rate of second primaries was found than in cancer of the rest of the oral cavity (tongue, buccal mucosa and palate) (26.6% versus 11.5%). In male patients, this difference was statistically significant (p less than 0.05). 4 tumours were synchronous. In those 4 patients, panendoscopy would not have contributed to an earlier diagnosis. Routine panendoscopy in oral cancer therefore seems not valid.

Female↗
PubMed1986

Incidence of squamous cell carcinoma of the head and neck: report of 1,000 cases.

The purpose of this paper is to define the incidence of squamous cell carcinoma (SCC) of the head and neck as seen at the Free University Hospital, Amsterdam, the Netherlands, in the last six years, according to the latest revised classification system of the International Union against Cancer (UICC, 1982). In addition, male to female ratios, relative frequencies at the various sites, age distribution, incidence of second or third primary and the relationship of distant metastases to the nodal metastases and the T-stage of the primary lesion are reported. These incidences are compared with those in other countries and the major differences are discussed.

Adult↗
PubMed1986

Multiple primary tumours in laryngeal cancer.

All 748 patients with squamous cell carcinomas of the larynx treated in the Free University Hospital, Amsterdam, between 1964 and 1983 were analysed retrospectively with regards to the occurrence of multiple primary tumours. One hundred and four (14 per cent) second primary tumours were reported. Seventy-three (10 per cent) were situated in the respiratory tract and upper digestive tract. Of these 73, 64 were localized in the lung. No esophageal carcinomas were reported. Male patients, with a glottic carcinoma had a statistically higher change of developing a second primary than female patients (14.5 per cent versus 0 per cent). In both sexes more multiple primary tumours occurred in supraglottic than in glottic cancers. Only in female patients was the difference statistically significant. Because of the high rate of lung carcinomas, and since most tumours are metachronous, bronchoscopy is justified at the initial work-up and is also to be considered at regular intervals during the follow-up period.

Carcinoma, Squamous Cell↗
PubMed1986

Chemosensitivity of human head and neck cancer xenografts in the clonogenic assay and in nude mice.

The potential use of human head and neck (H & N) tumours, growing in athymic nude mice, for preclinical assessment of cytostatic drug sensitivity in a soft agar cloning system was examined. Of 20 H & N tumour xenografts, obtained from 6 different xenograft lines, 17 demonstrated sufficient colony growth to evaluate in vitro drug sensitivity. Moreover, all xenografts provided enough cells to test 8 cytostatic drugs at 3 concentrations each. A dose-dependent inhibition of colony growth was obtained with all drugs tested, except methotrexate. Tumours were considered sensitive when the drug concentration required to inhibit colony formation by 50%, was less than 1/10 of the peak plasma concentration in patients. All H & N tumour lines were resistant to cisplatin, doxorubicin, hydroxyurea, mafosfamide (an in vitro active analogue of cyclophosphamide) and methotrexate. Bleomycin was active in 1/6 and 5-fluorouracil in 6/6 of the H & N tumour lines tested. In 32 cases the in vitro data of the H & N tumour lines and a chemosensitive rat rhabdomyosarcoma were compared directly with in vivo results obtained in nude mice. The clonogenic assay correctly predicted sensitivity in 4/6 (66.7%) and resistance in 21/26 (80.8%) of the cases. A lack of correlation was noted for methotrexate, 5-fluorouracil and cyclophosphamide. In vitro culture of human H & N xenografts may provide a means for a rapid and large scale screening to identify new drugs active against H & N malignancies. In addition the clonogenic assay may help to select drugs for subsequent testing in the nude mouse xenograft model. The lack of correlation for some drugs in the present study indicates that there are some limitations in the use of xenograft tumour material for in vitro testing of new drugs.

Animals↗
PubMed1986

Computed tomography: a mandatory investigational procedure for the T-staging of advanced laryngeal cancer.

Eighteen patients underwent computed tomography (CT) prior to total laryngectomy. In order to assess the accuracy of CT scanning in the evaluation of carcinoma of the larynx, CT scans were prospectively interpreted and the extent of the tumour was recorded. The tumour extent was evaluated on whole-mount histologic sections of the laryngeal specimens, prepared in the horizontal plane, similar to the CT scan. The results were compared to assess the ability of CT to identify tumour infiltration in the horizontal plane accurately. Based on these findings it is clear that CT has its influence on the T-staging and on the choice of treatment of laryngeal cancer, i.e. radiotherapy versus surgery.

Carcinoma↗
PubMed1986

Mucosal melanomas of the head and neck.

Mucosal melanoma is a rare tumor in the head and neck region. The presence of a pigmented lesion in the mucous membranes should raise the suspicion of malignant melanoma. It may at times be difficult for the pathologist to arrive at the diagnosis of malignant melanoma. It is mandatory, therefore, that the clinician provide the pathologist with a representative fresh biopsy specimen. One of the most intriguing features of this unusual tumor is the unpredictability of its clinical course. In some cases it is explosive, characterized by rapid, wide-spread dissemination. At other times, long dormant periods of more than 10 years' duration may be followed by recurrence with a fatal outcome. Radical surgery is the preferred treatment. Postoperative radiotherapy is applied when doubt exists as to the radicality of the surgical procedure. Treatment of recurrences, both local/regional, and distant, can be of great value to the patient. Therefore, otolaryngologists should be acquainted with the many local and systemic treatment modalities which have recently become available for recurrent melanoma. The ultimate prognosis is poor.

Aged↗
PubMed1985

Granular cell tumor of the proximal esophagus. A rare disease.

In 1926, Abrikossoff described a tumor, usually benign, which only rarely appears in the esophagus. In a 40-year-old woman, the authors found a multicentric granular cell tumor which was localized in the cervical esophagus and in the subcutaneous tissues over the right scapula; it was removed surgically. Granular cell tumors causing stenosis of the upper esophagus have been described only four times in the literature. Characteristics and treatment are discussed.

Adult↗
PubMed1985

Successful in vitro growth of human head and neck cancer after transplantation in nude mice.

Head and neck tumours from 14 different lines growing in athymic nude mice were cultured in a soft agar cloning assay. Eleven lines (79%) demonstrated growth with more than 100 colonies per 3 X 10(5) cells plated. These results are much more favourable than those obtained with head and neck tumours taken directly from the patient. It is suggested that the combination of the athymic nude mouse xenograft model with the clonogenic assay could serve as a new screening model for chemotherapeutic agents against head and neck cancer.

Animals↗
PubMed1985

Squamous cell carcinoma arising in the lining of odontogenic cysts. Report of 5 cases.

The lining of odontogenic cysts seldom gives rise to the development of a carcinoma. In a review of the literature by Gardner in 1975, 25 cases were accepted as such. In the present paper, 5 new cases are reported. These cases were encountered during a 14-year-period in which 292 oral carcinomas were registered, emphasizing the rarity of carcinomas arising from odontogenic cysts.

Aged↗
PubMed1985

Quantitative morphometry of squamous cell hyperplasia of the larynx.

The histopathological diagnosis of squamous cell hyperplasia of the larynx is very subjective. Since morphometry is highly reproducible, this method was applied to routine processed slides of 45 such lesions to assess objectively the epithelial characteristics. In each case measurements of nuclei of 50 cells in the basal, intermediate, and superficial cell layers were carried out. The data were analysed statistically. The findings suggest that quantitative morphometry may be helpful for the histopathological classification of squamous cell hyperplasia of the laryngeal mucosa.

Cell Nucleus↗
PubMed1984

Mononuclear phagocyte function in head and neck cancer. Chemotactic responsiveness of blood monocytes in correlation between histologic grade of the tumor and infiltration of these cells into the tumor area.

The chemotactic responsiveness of peripheral monocytes and the acid-phosphatase activity of tumor-infiltrating macrophages, as well as the ultrastructural appearance, were studied in 40 patients with squamous cell carcinoma of the head and neck. The chemotactic responsiveness was found to be decreased in carcinoma patients, and this value appeared to be positively correlated in individual patients with the number of tumor-infiltrating macrophages, as well as with the histologic grade of the tumor. Patients with poorly differentiated malignancies showed impaired monocyte chemotactic responsiveness and low numbers of tumor-infiltrating macrophages. Macrophages present in the parenchyma of the tumor showed a weak and diffuse pattern of acid phosphatase activity. The acid phosphatase activity of stromal macrophages was much stronger and distributed in foci. Electron microscopic examination of the parenchymal macrophages revealed low numbers of lysosomes and the presence of tumor cell debris in the cytoplasm of the cell, without any sign of a surrounding phagosomal membrane. Together with the weak cytochemical reactivity, this probably indicates the poor functional state of the phagocyte when infiltrated in the parenchyma of the tumor. Low molecular weight factors derived from the tumor are known to decrease chemotactic responsiveness of peripheral monocytes. The poor functional state of the macrophages infiltrated within tumor parenchyma might be explained by assuming that a high concentration of such factors in the near vicinity of malignant cells causes toxic effects in macrophages.

Adult↗