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Biomedical subjects

S K Tay

Publications and source records attributed to S K Tay.

At least 73 records · Page 4Linked to original sources
PubMed1990

Studies on cervical intraepithelial neoplasia: the level of octadeca-9,11-dienoic acid and measurement of free radical content by electron spin resonance spectroscopy.

The efficacy of electron spin resonance spectroscopy (a technique that measures free radicals) in detecting cervical intraepithelial neoplasia was evaluated in 68 women. In addition, electron spin resonance spectroscopic data were correlated with the phospholipid-esterified octadeca-9,11-dienoic acid (18:2(9,11]/octadeca-9,12-dienoic acid (18:2(9,12] molar ratio, a suggested marker of free radical damage to linoleic acid. Incubation of cervical epithelial cells with the spin-trap N-tert-butyl-alpha-phenylnitrone and subsequent examination by electron spin resonance spectroscopy gave signals from a nitroxide radical, which has been tentatively assigned to an adduct from either a carbon-centered lipid radical or a lipid alkoxyl radical; no significant differences in either the type of radical detected or the intensity of the signals was found between patients with cervical intraepithelial neoplasia and normal control subjects. There was no significant correlation between the intensity of the electron spin resonance signal and the phospholipid-esterified 18:2(9,11)/18:2(9,12) molar ratio. This finding provides no support for the classification of 18:2(9,11) as a "free radical product."

Cervix Uteri↗
PubMed1990

A histological and immunohistological study of cervical intraepithelial neoplasia in relation to recurrence after local treatment.

A retrospective histological study was performed on 23 patients who had presented with recurrent cervical intraepithelial neoplasia (CIN) 18 months or more after apparently adequate local destructive treatment and a comparable control group of 23 patients who had no recurrence at 18 months. All recurrences were in women with CIN 3. Detailed examination of pretreatment biopsies showed that there were significant differences in both the extent of crypt involvement (P less than 0.01) and maximum depth of CIN (P less than 0.01) between the recurrent groups and the comparison group of women without recurrence. There was also a significant difference in mitotic count between the two groups (P less than 0.01). Immunocytochemical staining for Langerhans' cells or human papilloma virus common antigen showed no significant difference between the two groups. A mitotic count of 35 per ten high-power fields or a depth of crypt involvement greater than 1.7 mm in the pretreatment biopsy was invariably associated with recurrence and identified 13/22 (59%) cases of recurrent disease. The histological reporting of these features may be of value in predicting a group of women at high risk of recurrence of CIN after local treatment.

Antigens, Viral↗
PubMed1990

Is genital human papillomavirus infection always sexually transmitted?

The occurrence of genital human papillomavirus (HPV) infection was studied prospectively by colposcopy and histology in 43 virginal and 162 sexually active women attending a colposcopy clinic. The study also included 111 husbands of the latter group. By colposcopic criteria, the prevalence of HPV infection was 51.1% in the virginal and 69.1% in the sexually active women. The prevalence was 77.1% among men whose wives had HPV infection compared to 13.3% among men whose wives did not have the infection (p less than 0.01). There was a strong association in genital HPV infection between husbands and wives as expected from a sexually transmissible disease. However, the high prevalence of the infection among the virginal women indicated that transmission of HPV by nonsexual modes was common. Genital HPV infection is ubiquitous and in women is not exclusively a venereal disease.

Adult↗
PubMed1989

Langerhans cell population in early invasive squamous cell carcinoma of the uterine cervix.

Langerhans cell counts were performed using indirect immunoperoxidase staining for S100 protein in 10 cases of early invasive squamous cell carcinoma of the cervix and 20 controls from routine hysterectomy specimens. There was a significant (p < 0.01) reduction in the number of Langerhans cells per unit sectional area of tumour tissue compared to the normal cervical epithelium. The density of Langerhans cells in the 3 patients with tumour metastasis in pelvic lymph nodes was further reduced. The low density of Langerhans cells in invasive squamous cell carcinoma compared to the normal state may reflect poor local immunosurveillance and may be related to progression and spread of the tumour.

Adult↗
PubMed1989

Traumatic pseudocyst of the pancreas--a case report.

Blunt trauma to the pancreas is not common. The pancreatic injury can range from simple bruising to complete transection often associated with other visceral injuries. Pseudocyst of the pancreas is a late complication presenting usually within six weeks of the injury. The treatment of choice is distal pancreatectomy.

Adult↗
PubMed1989

Primary mesenteric venous thrombosis--a case report.

Mesenteric venous thrombosis has been described to occur in cases where there has been no apparent cause. The diagnosis is usually delayed because the signs and symptoms are non-specific. A case of primary mesenteric venous thrombosis is reported below. Its presentation and pathology are discussed. Treatment is surgery with resection of gangrenous bowel and primary anastomosis. Post-operative anticoagulation is advocated.

Adult↗
PubMed1987

Recognition of cervical neoplasia by the estimation of a free-radical reaction product (octadeca-9,11-dienoic acid) in biopsy material.

Linoleic acid (18:2(9,12)) and its diene-conjugated isomer (18:2(9,11)) were measured in 65 cervical biopsy samples. Both the 18:2(9,11) concentration and the 18:2(9,11)/18:2(9,12) molar ratio showed highly significant differences between the normal and precancerous groups. Both showed a further significant increase in 4 invasive carcinomas. The findings in histologically normal areas from organs with precancer correlated significantly with the results in the precancerous lesions.

Biopsy↗
PubMed1987

Recognition of cervical neoplasia by the estimation of a free-radical reaction product (octadeca-9,11-dienoic acid) in exfoliated cells.

The molar ratio between a diene-conjugated linoleic-acid isomer (18:2(9,11)) and the parent linoleic acid (18:2(9,12)), both esterified as phospholipids, was significantly different in exfoliated cells from normal cervices and from cervices with colposcopic and cytological evidence of precancer. The measurement may provide a simple and perhaps improved alternative to cytological screening.

Adult↗
PubMed1987

A new fixed cryosection technique for the simultaneous immunocytochemical demonstration of T6 and S100 antigens.

A formalin-calcium fixation method of preparing cryosections is described, which allows demonstration of Langerhans' cells by S100 antigen staining on frozen sections. The number of Langerhans' cells given by T6 antigen staining is also higher in formalin-calcium fixed frozen sections than acetone fixed frozen sections. The preparation is suitable for dual demonstration of the two antigens on the same section enabling a more accurate numerical evaluation of Langerhans' cell populations in the normal cervical epithelium.

Adult↗
PubMed1987

Subpopulations of Langerhans' cells in cervical neoplasia.

Multiple markers were used to count Langerhans' cells in the cervix. In the normal cervix, thymocyte antigen (T6) and adenosine triphosphatase (ATPase) demonstrated the largest population of Langerhans' cells. MHC Class II positive cells were equivalent to 60%, and S100 positive cells were equivalent to 35% of T6 or ATPase positive cells. Whereas Langerhans' cells demonstrated by T6, ATPase, and MHC Class II antigen were evenly distributed throughout the epithelium, the S100 positive cells were seen predominantly near lymphocytic aggregates and capillaries. In human papillomavirus infection and cervical intraepithelial neoplasia the numbers of T6, ATPase, or MHC Class II positive Langerhans' cells were reduced by 60% but the S100 positive cells were almost completely depleted. These findings suggested that there were different subpopulations of Langerhans' cells in the cervical epithelium. The depletion of Langerhans' cells, particularly the selective depletion of the S100 positive subpopulation, might cause a localized immunodeficiency that impairs immune surveillance and the cell-mediated immune response to human papillomavirus infection and cervical intraepithelial neoplasia.

Adult↗
PubMed1987

Lymphocyte phenotypes in cervical intraepithelial neoplasia and human papillomavirus infection.

Lymphocyte phenotypes in cervical mucosa were studied using a panel of monoclonal antibodies. T lymphocytes were predominant both within the epithelium and in the subepithelial stroma. In the normal cervix, both the T4+ (helper/inducer) and T8+ (suppressor/cytotoxic) subsets were present in a ratio similar to that in the peripheral circulation. In human papillomavirus (HPV) infection and cervical intraepithelial neoplasia (CIN) there was depletion of intraepithelial lymphocytes, especially of T4+ subset, with reversal of the ratio of T4+ to T8+ subsets to less than one. In contrast, there was no significant reduction in the number of lymphocytes in the subepithelial stroma. Tac+ (antigen primed and clonal expanding) lymphocytes were absent both within the epithelium and in the subepithelial stroma. These findings support our suggestion that there is a localized immunodeficiency in HPV infection and CIN. The aetiological and therapeutic implications are discussed.

Adolescent↗
PubMed1987

Tissue macrophage response in human papillomavirus infection and cervical intraepithelial neoplasia.

Tissue macrophages in the uterine cervix were studied immunocytochemically with monoclonal antibody (MoAb) 3.9 which reacts with the majority of macrophages, and E11 which is specific for the C3b receptor, CR1. Samples from five normal women, six with human papillomavirus (HPV) infection and 10 with cervical intraepithelial neoplasia (CIN) were tested. A small population of MoAb 3.9 positive and only occasional MoAb E11 positive macrophages were found in the normal cervix. In HPV infection and CIN there was a significant infiltration of MoAb 3.9 positive and MoAb E11 positive macrophages in both the epithelium and the stroma. The pattern of infiltration in these groups of women suggests that these macrophages were most likely to be functioning as the first line of defence against the spread of the virus infection, either through a direct anti-virus mechanism or non-specific phagocytosis.

Adult↗
PubMed1987

Natural killer cells in cervical intraepithelial neoplasia and human papillomavirus infection.

A semiquantitative immunocytochemical study of natural killer (NK) cells in cervical mucosa was performed by the immunoperoxidase technique using anti-Leu-7 and anti-Leu-11 monoclonal antibodies. NK cells were present in two of the five normal controls and five of six specimens showing human papillomavirus (HPV) infection. Of the 12 CIN studied, six were positive for both Leu-7 and Leu-11 staining and three were positive for Leu-11 alone. NK cells were found predominantly in the subepithelial stroma. The frequency and pattern of distribution of these cells were similar in all grades of CIN. The number of NK cells present was usually small but the degree of infiltration by Leu-11 positive cells was pronounced in two HPV infections and in one CIN 1. NK cells may have a role in surveillance against HPV infection and the development and progression of CIN.

Adult↗
PubMed1987

Management of squamous atypia (borderline nuclear abnormalities): repeat cytology or colposcopy?

A prospective cytological, colposcopic and histological study was conducted in 44 women with cervical cytology showing borderline nuclear abnormalities insufficient for the diagnosis of dyskaryosis. Atypical squamous epithelium was found on colposcopy in 41 patients and cervical intraepithelial neoplasia (CIN) was diagnosed on histology in 33 patients (75%) including 10 with CIN 3. Repeat cytology obtained under colposcopic vision was negative in 12 (33.4%) patients with CIN. The high prevalence of CIN in smears showing only borderline nuclear abnormalities and the high false negative rate of repeat cytology indicate that colposcopy should be the first line of management for these patients.

Adult↗
PubMed1987

Routine papillomavirus antigen staining of cervical punch biopsy specimens.

Immunocytochemical staining for papillomavirus antigen was carried out on 1147 consecutive cervical punch biopsy specimens over 12 months. Of 876 cases with cervical intraepithelial neoplasia (CIN) 351, were antigen positive and of 49 cases with histological evidence of human papillomavirus (HPV) infection but no CIN, 14 were positive. There were 204 cases reported to be normal on routine histological examination and 12 cases reported to show features suggestive but not diagnostic of HPV infection. Of the normal group, 24 (12%) were antigen positive and of the equivocal group, two were positive. In 122 of the normal or equivocal groups cytological examination was repeated at the time of colposcopy, and dyskaryosis was reported in 36. In only four cases was disease shown by HPV antigen staining when there was no diagnostic histological or cytological abnormality. HPV antigen staining assists in the recognition of the range of histological changes associated with productive HPV infection but is an insensitive test and has only limited value in supplementing histological and cytological examinations as a diagnostic aid in routine colposcopic pathology.

Antigens, Viral↗
PubMed1987

Recognition of cervical neoplasia by the estimation of a free-radical reaction product (octadeca-9,11-dienoic acid) in exfoliated cells.

The molar ratio between a diene-conjugated linoleic-acid isomer (18:2(9,11)) and the parent linoleic acid (18:2(9,12)), both esterified as phospholipids, was significantly different in exfoliated cells from normal cervices and from cervices with colposcopic and cytological evidence of precancer. The measurement may provide a simple and perhaps improved alternative to cytological screening.

Biomarkers, Tumor↗