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Biomedical subjects

J K Field

Publications and source records attributed to J K Field.

At least 109 records · Page 6Linked to original sources
PubMed1989

Elevated expression of the c-myc oncoprotein correlates with poor prognosis in head and neck squamous cell carcinoma.

We quantitated c-myc oncoprotein in 44 squamous cell carcinomas of the head and neck using an enzyme-linked immunosorbence assay. The clinicopathological parameters of these patients were followed up for between 3 and 60 months and analysed for any correlations with observed levels of c-myc protein using the Kruskal-Wallis one-way analysis of variance method. Although no statistical correlation was found between different clinicopathological parameters (patient age, sex, TNM staging, number of lymph nodes invaded, extracapsular rupture of the tumour, its histopathological differentiation, or its site), the survival periods of patients with tumours possessing elevated levels of c-myc protein were found to be statistically shorter than those with lower levels of c-myc expression, (P less than 0.02). This indicates that c-myc expression may be an effective prognostic indicator in head and neck cancer.

Animals↗
PubMed1989

Does Candida have a role in oral epithelial neoplasia?

Candida species are responsible for a wide variety of superficial infections of man [59] and the pathogenic role of these yeasts in many conditions has now been defined. There is, however, a great deal of controversy concerning the role of Candida species in the development of epithelial neoplasia. Vaginal and cutaneous candidosis are relatively common but there is little firm clinical or epidemiological evidence to link them to cervical neoplasia or skin carcinoma [59]. The converse is true however for oral candidosis where chronic Candida infection and neoplasia have been strongly linked. The aim of this review is to explore and evaluate the experimental and epidemiological evidence supporting an association between Candida species and oral neoplasia.

Animals↗
PubMed1987

Expression of oncogenes in human tumours with special reference to the head and neck region.

A major recent advance in cancer research has been in the field of oncogenes. Oncogenes are genes with a proven cancer association and which appear to be particularly implicated in cellular regulation and proliferation. The oncogenic potential of specific cellular genes has now been recognised and this has influenced current thinking concerning the initiation of carcinogenesis. The specific role of an oncogene is still incompletely understood but research with one particular oncogene (ras) has demonstrated that it can be involved in more than one stage of multi-step carcinogenesis. New techniques are being developed and evaluated to determine the expression of specific oncogenes in normal and neoplastic tissues, with a view to using them in future diagnostic immuno-histopathological methods. This review describes the concept of oncogenes and discusses their role in the development of neoplasia. The results of the expression of various oncogenes in human malignancies with special reference to the head and neck regions are discussed. Finally, the future prospects of this research field are examined their and its possible implications in cancer therapy.

Adenoma, Pleomorphic↗
PubMed1984

Sex differences in sexual needs and desires.

Female and male responses on attitudes toward foreplay prior to sexual intercourse, sexual intercourse, and afterplay following sexual intercourse, were compared. Foreplay was defined as the sexual activity that occurs before sexual intercourse, whereas afterplay was defined as the interaction such as hugging, holding, talking, and so forth that occurs after sexual intercourse. The subjects were 39 men and 49 women students enrolled in various courses at the University of Kansas. The mean age of the men was 22.1 years, while the women averaged 21.0 years. A voluntary questionnaire was given to the students, and they were asked to fill it out at home and return it during the next class meeting. The results indicated that there were significant sex differences in sexual needs and desires. When given a choice between foreplay, intercourse, and afterplay, women indicated that foreplay was the most important part of a sexual encounter, while men felt intercourse was the most important aspect. Women also indicated that they wanted to spend more time in foreplay, as well as more time in afterplay, than did men. It is concluded from this study that women are more likely than men to report enjoying both foreplay and afterplay more than intercourse, while men are more likely to report enjoying intercourse.

Adult↗
PubMed1983

Serum regulation of the estrogen responsiveness of the human breast cancer cell line MCF-7.

Initially after receiving MCF-7 cells, we were able to confirm their estrogen responsiveness. We observed significant increases in thymidine incorporation, in thymidine kinase activity, and in cell numbers in response to 10(-8) M estradiol. Subsequently, however, the cells failed to show a response to estradiol. A growth response to estradiol could be restored by increasing the serum concentration in the medium. Cells grown in 15% serum (calf or human) responded to estradiol with increased rates of growth and thymidine incorporation and increased activities of thymidine kinase and DNA polymerase. We suggest that there is present in serum a "factor" which can influence the expression of a growth response to estradiol.

Blood↗
PubMed1982

A microcomputer program for analysis of nucleic acid hybridization data.

The study of nucleic acid hybridization is facilitated by computer mediated fitting of theoretical models to experimental data. This paper describes a non-linear curve fitting program, using the 'Patternsearch' algorithm, written in BASIC for the Apple II microcomputer. The advantages and disadvantages of using a microcomputer for local data processing are discussed.

Computers↗
PubMedDate not supplied

Microsatellite instability and p53 mutations in hepatocellular carcinoma.

We have studied 27 hepatocellular carcinomas (HCCs) to identify possible relationships between microsatellite instability (MSI), p53 mutations, and HBV infection in hepatocarcinogenesis. MSI was assessed using 19 polymorphic markers and the poly(A) tract BAT-26. All coding regions of p53 were examined for mutations. Tumors were also examined for presence of hepatitis B virus (HBV) DNA sequences; 66.6% of the samples exhibit MSI in at least one microsatellite locus and 44% in two or three loci. None of the tumors examined showed alterations in BAT-26. Moreover, 73.3% of samples with indication of HBV infection showed instability in at least one marker. No association between MSI and pathological profile was found. Five (18.5%) samples harbored mutations in p53, three missense, and two insertions, all in exons 5 and 8 not previously reported. No mutations were detected in codon 249, which has been linked with dietary intake of aflatoxins. Our results support the hypothesis that HCC is a "low" MSI tumor. Only 1/5 samples with MSI in more than two markers harbored a mutation in p53. Although the number of samples is too small to support a statistical significance, this finding may indicate an inverse relationship between p53 mutations and MSI in HCC.

Base Sequence↗
PubMedDate not supplied

A further study of the inheritance of racing performance in thoroughbred horses.

In an analysis of handicap ratings of 1158 3-year-old thoroughbred racehorses, estimates were obtained for the effects of sex differences, the correlation between mates, the effectiveness of selection in males and females, and the heritability of racing performance. The results agreed closely with those of a previous study, and indicated a heritability of about 0.35 to 0.40, some assortative mating, and highly effective selection for performance.

Animals↗
PubMedDate not supplied

Von Hippel-Lindau tumour suppressor gene is not involved in sporadic human breast cancer.

OBJECTIVE: Mutations of the von Hippel-Lindau (vhl) gene, as well as allelic loss at the gene region (3p25-26) have been described in sporadic cases of the tumour types participating in VHL disease, but also in cancers not associated with the syndrome. In this study, we attempted mutation analysis of the vhl gene, as well as detection of allelic loss at 3p25-26 in sporadic human breast cancer. METHODS: Eighty-two tumour specimens were screened for loss of heterozygosity (LOH) at the vhl region, and compared to the adjacent, histologically normal tissue. Furthermore, mutations within the three exons of vhl in the same panel of tumours were detected using SSCP and heteroduplex analysis and direct sequencing. RESULTS: To our knowledge this is the first mutational analysis reported for the vhl gene in breast cancer, however we failed to reveal any mutations in the specimens examined. All the cases were informative for at least one of the microsatellite markers tested, 24 (29.2%) exhibited LOH at 3p25-26. Clinical and pathological data were available for all tumours examined, however no significant correlations were encountered. CONCLUSION: These results strongly indicate against a critical involvement of the tumour suppressor vhl in breast carcinogenesis.

Breast↗
PubMedDate not supplied

Histological and molecular mapping of adenocarcinoma of the oesophagus and gastroesophageal junction: loss of heterozygosity occurs in histologically normal epithelium in the oesophagus and stomach.

Seventy malignant, premalignant and histologically normal biopsies from 7 oesophagogastrectomy specimens of adenocarcinomas of the lower oesophagus and gastroesophageal junction were analysed for loss of heterozygosity (LOH) at 9 known or putative gene loci. LOH was detected in 20 of 27 (74%) malignant biopsies, 4 of 7 (57%) biopsies of dysplasia, 2 of 12 (25%) biopsies of histologically normal oesophagus adjacent to adenocarcinoma, and in 2 of 14 (14%) biopsies of histologically normal stomach adjacent to adenocarcinoma. LOH at the VHL, APC, CDKN2 and DCC tumour suppressor and MSH3 mismatch repair gene loci can be detected in histologically normal tissue and in adjacent adenocarcinoma, and are potential markers of early neoplastic progression.

Adenocarcinoma↗
PubMedDate not supplied

A new rare allele at the CGG repeat polymorphism in the first intron of human c-H-ras gene.

We have examined a region in the first intron of the human c-H-ras gene containing a CGG repeat. This region was previously shown to be variable in length. The length variation was attributed to the presence of the CGG repeat after estimation of its electrophoretic mobility. In the present report we have characterized in detail this region by PCR-RFLP and automated sequencing, in a total of 102 histologically normal tissues from unrelated individuals affected by lung and breast cancer. Four alleles were detected and analysis of their internal sequence showed that the length alterations of this region were due to the presence of 5, 6, 8 and 9 CGG triplets respectively. The last three occur most often (44.1%, 34.8%, 20.6% respectively) and coincide with three previously reported alleles (Riggins et al, Hum Mol Genet 9: 775, 1992). The fourth allele consisting of 5 repeats is a rare one (0.5%), whilst alleles with 7, and a previously reported one suggested to comprise 11 repeats (1%) were not present in our cohort. This polymorphism coincides in position with an element that was previously shown to possess regulatory activity.

Alleles↗
PubMedDate not supplied

C-erbB-2 expression in squamous cell carcinoma of the head and neck.

Seventy-five squamous cell carcinomas of the head and neck were analysed for c-erbB-2 expression using immunohistochemical techniques with four different c-erbB-2 antibodies. No membrane staining was seen in any of the squamous cell carcinomas studied with any of the antibodies; however, c-erbB-2 cytoplasmic staining was seen in 60 per cent of the tumours. The significance of cytoplasmic staining is discussed and that it may possibly represent elevated c-erbB-2 expression in squamous cell carcinomas. C-erbB-2 cytoplasmic staining was also observed in 10 of 23 normal specimens obtained from the resection margin of the tumours. No correlations were found between positive c-erbB-2 cytoplasmic staining and any of the clinicopathological parameters or survival.

Biomarkers, Tumor↗
PubMedDate not supplied

Expression of ras Rb1 and p53 proteins in human breast cancer.

The ras, Rb and p53 genes have been implicated in the development of human breast cancer. Qualitative or quantitative changes in the expression of the ras p21 may lead to cell transformation, and this has been previously demonstrated in breast cancer. Both the retinoblastoma protein (Rb1) and the p53 gene product appear to function as negative regulators of cell division. We have investigated the expression of ras p21, Rb1 and p53 proteins in human breast cancer patients immunohistochemically, and correlated the results with a range of clinical and pathological parameters. Ras p21 expression was elevated in 65 per cent and p53 in 23 per cent of cases. Rb1 was expressed in 58 per cent of breast cancer tissues and in 75 per cent of normal tissue. Only four patients were found to have loss of Rb1 expression and also overexpression of both p53 and ras gene products. No correlations were found between the expression of these three genes and menopausal status, histological types or tumour grade. However, a correlation was found between Rb1 loss of expression and tumour diameter (greater than 2 cms), and no lymph node metastasis. Also, a significantly higher number of p53 staining specimens were found to be overexpressing the ras gene. These results suggest that all three oncogenes are most likely involved in the development of breast cancer but that their role is complex.

Animals↗
PubMedDate not supplied

Ras p21 expression in brain tumors: elevated expression in malignant astrocytomas and glioblastomas multiforme.

We have employed an immunohistochemical analysis to study the ras p21 oncoprotein in a total of 41 brain tumors and 1 reactive gliosis. The tumors included 33 astrocytomas, 1 oligodendroglioma, 2 ependymomas, 1 neurilemmoma, 1 malignant meningioma, 1 neuroblastoma and 2 medulloblastomas. Our results indicate that elevated ras p21 expression is a common feature in a range of brain tumors. In particular, elevated ras p21 expression has been found in 18 out of 24 high grade astrocytomas (malignant astrocytomas and glioblastomas multiforme) compared to 3 out of 9 low grade (well differentiated astrocytomas) (P less than 0.05). These results suggest that ras p21 expression may be an important molecular marker of the malignant astrocytomas and glioblastomas multiforme.

Astrocytoma↗
PubMedDate not supplied

p53 expression in cytologic specimens from benign and malignant breast lesions.

This study was undertaken to determine the expression of p53 gene in cytologic specimens from benign and malignant breast lesions. To detect p53 an immunocytochemical assay with p53 (pAb421) monoclonal antibody was used. Abnormalities in p53 expression were found in 19 out of 40 Fine Needle Aspiration (FNA) smears with infiltrating ductal breast carcinomas. Benign epithelial breast cells obtained from fibroadenomas, fibrocystic disease and smears from nipple discharge reacted negatively for p53 in 38 out of 39 cases. Moderate positive reaction, confined to a few clusters of epithelial cells, was observed in one smear of fibroadenoma with cellularity. The results recorded in this study show that no significant association was found between p53 staining and stage of disease, tumor size or nodal status and that the immunocytochemical assay represents a simple method for the detection of p53 associated proteins in breast lesions.

Adenofibroma↗