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Biomedical subjects

G B Snow

Publications and source records attributed to G B Snow.

At least 19 recordsLinked to original sources
PubMed1992

Prevalence and expression of human papillomavirus in tonsillar carcinomas, indicating a possible viral etiology.

The presence of human papillomavirus (HPV) DNA was assessed in biopsies of tonsillar carcinomas (n = 10) and cases of tonsillitis (n = 7), serving as controls, by general-primer-mediated PCR (GP-PCR). All carcinomas appeared HPV-positive, whereas all cases of tonsillitis were HPV-negative. Additional type-specific PCR for HPV 6, 11, 16, 18, 31 and 33 revealed that 4 carcinomas contained HPV 16 DNA, 4 contained HPV 33 DNA and 1 contained an HPV 16/33 double infection. False positivity was excluded by additional Southern blot analysis of type-specific PCR-positive samples (n = 4). Further characterization of GP-PCR products by sequence analysis revealed that 2 carcinomas contained still uncharacterized HPV genotypes; one of these also contained HPV 33 DNA and one was negative by type-specific PCR. Application of RNA PCR revealed expression of HPV 16 or HPV 33 E7 encoding spliced E6*1 transcripts in all tonsillar carcinomas (n = 4) examined. Additional non-radioactive RNA in situ hybridization performed on 3 biopsies revealed the presence of HPV 16 or HPV 33 E7 transcripts exclusively localized within the carcinoma cells, whereas stroma stained negative. These findings strongly support a role for certain HPV types in the pathogenesis of tonsillar carcinomas.

Amino Acid Sequence↗
PubMed1992

[Otitis media with effusion as initial symptom of a parapharyngeal tumor].

Two patients are described who had unilateral otitis media with effusion (OME) as the first and only symptom of a parapharyngeal tumour. The first patient, a 77-year-old woman, was operated 14 months after the onset of the OME. A polymorphous adenocarcinoma was resected from the left parapharyngeal space. In the second patient, a 59-year-old man, the diagnosis was established 7 months after the first symptom. A pleomorphic adenoma was removed surgically from the right parapharyngeal space. In case of a persistent unilateral OME in an adult, a parapharyngeal tumour should be considered as one of the possible causes.

Adenocarcinoma↗
PubMed1992

Expression and characterization of two differentiation antigens in human stratified squamous epithelia and carcinomas.

Using viable cells of a human squamous-cell carcinoma (SCC) cell line as immunogen, we generated 2 monoclonal antibodies, MAbs K984 and K928, to SCC surface antigens. Immunoperoxidase staining of frozen sections of normal epidermis revealed that MAb K984 reacts with the poorly differentiated basal cells, while MAb K928 is reactive with the more highly differentiated suprabasal cells. A similar complementary reaction pattern of these antibodies was demonstrated in the majority of well-differentiated human tumors and some moderately differentiated SCCs. In contrast, simultaneous reactivity of MAb K984 and K928 was found for the majority of cells within other well- and moderately differentiated SCCs, as well as all poorly differentiated SCCs. Further biochemical characterization indicated that the antigen recognized by MAb K984 is similar to the one recognized by MAb SF-25. MAb K928 recognizes a 50- to 55-kDa molecule under non-reducing conditions. Antibodies with similar features to MAb K928 have not been described previously. The antigens recognized by MAbs K984 and K928 can be regarded as novel markers associated with cellular maturation in squamous epithelia. The antigen detected by MAb K984 is probably associated with the proliferating fraction in SCCs.

Antibodies, Monoclonal↗
PubMed1992

[Neck lymph node dissection in squamous cell carcinoma originating in the head-and-neck area; the significance for the prognosis].

Neck dissection has a therapeutical as well as a prognostic relevance with respect to regional recurrence and distant metastases. Between January 1973 and July 1986 576 neck dissections in 511 patients (396 men, 115 women, among whom 486 with squamous cell carcinoma of the head and neck, and 14 with neck metastases of an unknown primary tumour) were performed at the department of Otolaryngology-Head and Neck Surgery of the Free University Hospital, Amsterdam. Patients with tumour at the margins were excluded. Recurrence-free curves were calculated according to Kaplan-Meier and the log rank test was used to test the differences. All patients underwent a comprehensive neck dissection and were irradiated postoperatively when three or more tumour-positive nodes or extranodal spread were reported by the pathologist. Endpoint for analysis was occurrence of an ipsilateral neck recurrence or of a distant metastasis. Figures were corrected for a simultaneous recurrence at a higher level. A total of 29 neck recurrences (7.2%; n = 523) and 26 distant metastases (10.7%; n = 281) were demonstrated in the 5-year follow-up period. The number of positive nodes was of prognostic significance for both events (p = 0.039 and p = 0.0027). Extranodal spread was shown only to increase the incidence of distant metastases (p = 0.017), whereas its prognostic value with regard to recurrence in the neck was nullified by the strict institution of postoperative radiotherapy. It is recommended to give radiotherapy to patients with two positive nodes and possibly to every patient with a histopathologically positive neck.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Autoantibodies against constituents of neutrophils in the diagnosis and treatment of (isolated) subglottic stenosis.

Six patients had a subglottic stenosis either as a presenting symptom or as a manifestation of a systemic disease. All patients had in common the presence of circulating autoantibodies against constituents of neutrophils on indirect immunofluorescence. Cytoplasmic and perinuclear staining patterns were recognized. Such autoantibodies have been reported in Wegener's granulomatosis, microscopic polyarteritis, (idiopathic) glomerulonephritis, and Churg-Strauss syndrome. However, only one of the six patients fulfilled the criteria for these conditions. Because a positive test for autoantibodies against constituents of neutrophils is rare in other conditions and because other diseases had been excluded, we suggest that this places subglottic stenosis within the spectrum of necrotizing (granulomatous) vasculitis. The consequences for therapy are discussed.

Adolescent↗
PubMed1992

Management of cervical lymph nodes in patients with head and neck cancer.

The status of the cervical lymph nodes is the single most important prognostic factor in head and neck cancer. Unfortunately, clinical assessment of the neck is not very accurate, although newer imaging techniques such as CT, MRI and ultrasound-guided fine needle aspiration cytology can be used to improve upon the results of clinical palpation alone. While diagnostic techniques remain less than 100% accurate, the risk of occult disease in the neck will remain. If this occurrence is judged to be greater than 15-20%, elective treatment to the neck may then be justified. When the neck is treated surgically, histological information can be gained which has both prognostic and therapeutic implications. Indications for the use of surgery and radiotherapy for the elective and therapeutic management of the neck and the results of such treatment are discussed.

Combined Modality Therapy↗
PubMed1992

Micrometastases from squamous cell carcinoma in neck dissection specimens.

The incidence of micrometastases in cervical lymph nodes from squamous cell carcinomas of the head and neck was studied using routine histopathological examination. Micrometastases were found in 66 lymph nodes in 41 of the 92 tumor-positive neck dissection specimens. The detection of these micrometastases influenced postoperative treatment in 3 of the 77 patients with neck node metastases. The value of additional sectioning for detecting micrometastases was thus assessed. Sectioning at a deeper level in 600 originally histopathologically negative lymph nodes from 64 patients revealed 7 additional micrometastases in 5 patients. Antikeratin staining with a mixture of two monoclonal antibodies (AE1 and AE3) revealed 4 micrometastases in 739 originally histopathologically negative lymph nodes in 3 of 13 patients studied. Because of the unknown prognostic significance of micrometastases and the consequent arbitrary consequences for postoperative treatment, present findings show that the extra workload of immunostaining and deeper sectioning does not warrant their routine use in clinical practise.

Carcinoma, Squamous Cell↗
PubMed1992

Potential for targeting head and neck squamous cell carcinoma with monoclonal antibody K984.

In previous reports we have described the development of mAb K984, reactive with an epitope expressed on the outer cell surface of undifferentiated, proliferating cells in normal stratified squamous epithelia and their neoplastic counterparts. The K984 antigen was also found to be homogeneously expressed by in vitro cultured squamous cell carcinoma (SCC) cell lines. In the present study we demonstrate that mAb K984 induces a significant, dose-dependent growth inhibition when SCC cells are grown in vitro as monolayer cultures in the presence of mAb K984. These data seem to indicate that mAb K984 has potential for tumour targeting, especially in a therapeutic setting. As a first approach to evaluate the suitability of mAb K984 for tumour targeting in vivo, radiolabelled mAb K984 was administered to SCC-xenografted nude mice. Selective tumour accumulation of mAb K984 was observed. Tumour to blood ratios and tumour to non-tumour ratios, as based on the biodistribution data, were at least ten times higher in case of the specific mAb K984 when compared to another non-specific, isotype-matched control antibody. mAb K984 was also capable of visualizing tumour deposits in xenografted nude mice. The corollary of these findings is that the mAb K984-defined antigen probably is involved in the regulation of proliferation of stratified squamous epithelium and squamous cell carcinoma and that mAb K984 has potential for specific tumour targeting.

Animals↗
PubMed1992

Delay in diagnosis of oral squamous cell carcinoma; a report from The Netherlands.

The referral pattern, patients' and doctors' delay of a limited number of 50 patients suffering from oral squamous cell carcinoma have been investigated. The majority of the patients consulted the family doctor as the first source of help. The mean patients' and doctors' delay was 103 and 22 days, respectively the median being 35 and 11 days, respectively. The gender, dental status, site and tumour size did not show a significant correlation with the delay. Measures directed to the early detection of oral cancer should place special emphasis on the patients' delay.

Attitude to Health↗
PubMed1992

Squamous cell carcinoma of the nasal vestibule.

We reviewed 30 patients with squamous cell carcinoma of the nasal vestibule to present our experience of their management and to evaluate the prognostic factors that may influence their outcome. For T1 lesions radiotherapy remains the treatment of choice, because of the superior cosmetic result. Fifteen (68 per cent) out of 22 patients with T2 lesions were treated with primary radiotherapy. Surgery however, was eventually required in 16 (72 per cent) out of 22 patients, either as a primary treatment (seven patients) or as salvage surgery (nine patients). For the larger T3 lesions the treatment of choice is surgery followed by post-operative radiotherapy where appropriate. Regional nodal metastases at the time of presentation were a significant indicator of local and regional recurrence and of prognosis. The cause specific five-year survival for patients with an uninvolved neck (22 patients) was 100 per cent compared with 38 per cent for patients with nodal metastases at presentation (eight patients). Elective treatment for uninvolved regional nodes is not considered necessary.

Adult↗
PubMed1992

Radioimmunotherapy of human head and neck squamous cell carcinoma xenografts with 131I-labelled monoclonal antibody E48 IgG.

Monoclonal antibody (MAb) E48 reacts with a 22 kD antigen exclusively expressed in squamous and transitional epithelia and their neoplastic counterparts. Radiolabelled with 99mTc, MAb E48 is capable of targeting metastatic and recurrent disease in patients with head and neck cancer. In this study, the capacity of 131I-labelled MAb E48 to eradicate xenografts of human squamous cell carcinoma of the head and neck (HNSCC) in nude mice was examined. Experimental groups received a single i.v. bolus injection of 400 microCi MAb E48 IgG (number of mice (n = 6, number of tumours (t) = 9) or 800 microCi MAb E48 IgG (n) = 5,t = 7), whereas control groups received either diluent (n = 3,t = 5), unlabelled MAb E48 IgG (n = 4,t = 5) or 800 microCi 131I-labelled isotype-matched control MAb (n = 6,t = 9). A 4.1-fold increase in the median tumour volume doubling time and regression of two out of ten tumours (20%) was observed in mice treated with 400 microCi. In mice treated with 800 microCi. In mice treated with 800 microCi, two out of seven tumours (29%) showed complete remission without regrowth during follow-up (greater than 3 months). Median tumour volume doubling time in the remaining five tumours was increased 7.8-fold. No antitumour effects were observed in mice injected with diluent, unlabelled MAb E48 or 131I-labelled control MAb. In the same xenograft model, chemotherapy with doxorubicin, 5-fluorouracil, cisplatin, bleomycin, methotrexate or 2',2'-difluorodeoxycytidine yielded a less profound effect on tumour volume doubling time. Increases in tumour volume doubling time with these chemotherapeutic agents were 4, 2.2, 2.1, 1.7, 0, and 2.6 respectively. Moreover, no cures were observed with any of these chemotherapeutic agents. From the tissue distribution of 800 microCi MAb E48, the absorbed cumulative radiation doses of tumour and various organs were calculated using the trapezoid integration method for the area under the curve. To tumour xenografts, 12,170 cGy was delivered, blood received 2,984 cGy, whereas in every other tissue the accumulated dose was less than 6% of the dose delivered to tumour. These data, describing the first radiolabelled MAb with therapeutic efficacy against HNSCC, suggest radioimmunotherapy with MAb E48 to be a potential therapeutic modality for the treatment of head and neck cancer.

Animals↗
PubMed1992

Human papillomavirus (HPV) type 16 and 33 E6/E7 region transcripts in tonsillar carcinomas can originate from integrated and episomal HPV DNA.

This study was undertaken to determine whether human papillomavirus (HPV) E6/E7 gene transcription in tonsillar carcinomas is correlated with viral DNA integration. Therefore, tonsillar carcinomas containing HPV-16 (n = 2) and HPV-33 (n = 2) DNA were analysed for the viral physical state and transcription of the E6/E7 region. Southern blot analysis, DNA polymerase chain reaction (PCR) and, eventually, two-dimensional gel electrophoresis revealed indications for the presence of only episomal DNA in the HPV-16-containing biopsies and only integrated DNA in one HPV-33-containing biopsy. The second HPV-33-containing carcinoma, from which one biopsy and two resected tumour specimens were analysed, showed a rather complex physical state profile. The biopsy of this tumour contained only episomal DNA, one resected tumour part contained only integrated DNA and the remaining tumour part contained both integrated and episomal HPV-33 DNA. Independent of the viral physical state, all biopsies and resected tumour parts tested showed the presence of E6/E7 transcripts as determined by RNA PCR. The results indicate that E6/E7 transcripts in tonsillar carcinomas can originate from integrated as well as episomal HPV DNA.

Base Sequence↗
PubMed1992

T3 laryngeal cancer: a retrospective study of the Dutch Head and Neck Oncology Cooperative Group: study design and general results.

511 Patients with T3 N0-3 M0 squamous cell carcinoma of the larynx, treated in the Netherlands from 1975 until 1984, were retrospectively analysed. Four different treatment policies were followed: primary surgery, planned combination of radiotherapy and surgery, primary radical radiotherapy, and selective radiotherapy. General results are presented. Local control rate was 72%. Regional control rate was 90% for clinically N0 patients and 78% for clinically N+ patients. Salvage therapy was overall successful in 38%. Surgical salvage for local radiation failures (with regional relapse) was successful in 69%, and for regional failures (without local relapse) in 46%. Ultimate locoregional control was 78% and, due to 8% distant metastases, 5-year actuarial corrected survival was 70%. Prognosis did not improve over the years. Corrected survival was independently correlated with tumour extension, involvement of neck nodes and treatment strategy. Corrected survival was similar for primary radiotherapy and primary surgery, but significantly better for planned combined therapy. Multiple primary tumours occurred significantly more often in male (19.5%) than in female patients (7.3%) (P = 0.05), the bronchus being most commonly affected. Cumulative actuarial risk for metachronous tumour was 15% after 5 years and 30% after 10 years so prevention and early detection of these second tumours may play the most important role in improving overall survival rates in the future.

Adult↗
PubMed1992

Possible premalignant character of oral lichen planus. The Amsterdam experience.

In the present paper the 21-yr experience of the Department of Oral and Maxillofacial Surgery and Oral Pathology, and the Department of Otorhinolaryngology of the Free University Hospital, Amsterdam, is reported with regard to the possible premalignant character of oral lichen planus. The study consists of two parts: 1) the follow-up of 113 patients with histopathologically proven oral lichen planus, and 2) a search for lichen planus in 727 patients who have been admitted for oral cancer. Three patients with histopathologically proven lichen planus developed a squamous cell carcinoma in an average follow-up period of 7 yr. In the 727 patients with oral cancer, two additional patients with the simultaneous occurrence of oral lichen planus were observed. Our experience gives some but not very strong support to the hypothesis that oral lichen planus is a premalignant condition.

Adult↗
PubMed1992

Histological reclassification of 101 intraoral salivary gland tumours (new WHO classification).

The epithelial salivary gland tumours have for many years been categorised according to the 1972 World Health Organisation (WHO) classification. In 1990 a proposed revision of this classification was elaborated. In this study 101 intraoral salivary gland tumours were reclassified accordingly. In 29 of the cases the original histological diagnosis was changed, which in most cases, occurred in the benign or malignant tumour groups. In seven cases the diagnosis was changed from benign to malignant or vice versa. The results of this study show that the histological classification of intraoral salivary gland tumours remains difficult, even when applying the new WHO classification.

Adolescent↗