Molecular assessment of p53 abnormalities at the invasive front of oral squamous cell carcinomas.

BACKGROUND: The prognostic significance of the invasive tumor front in squamous cell carcinomas has recently been recognized. The aim of the present study was to investigate possible molecular mechanisms underlying the significance of this area in oral squamous cell carcinomas. METHODS: We used immunohistochemical and molecular genetic techniques to investigate whether p53 alterations at the invasive tumor front could determine the aggressiveness of oral cancers. RESULTS: p53 Overexpression was detected in 52% to 56% (four different p53 antibodies) of 100 carcinomas studied. The concordance rate between results of immunohistochemistry and genetic analysis was 60%. No correlation was found between p53 status of the tumors and clinicopathologic parameters analyzed statistically. CONCLUSIONS: p53 Alterations have no prognostic impact in oral squamous cell carcinomas and apparently do not represent a molecular basis for the biologic significance of the invasive tumor front. The detection of discordant p53 aberrations between primary and second primary carcinomas in some patients provide evidence for their independent origin, with possible impact on prevention and therapy.

The number of times attended as a factor in the success of a comprehensive hospital-based approach to health promotion.

This study assesses the relationship between a perceived change in a health-related behavior or attitude and the number of times an individual participates in a weekly hospital-based health promotion program. A survey was distributed to participants in April 1995. A univariate probit evaluation shows that the number of times attended and age have positive effects on the likelihood of change. As the number of times an individual attends increases, the more likely the person is to change, possibly revealing a reinforcement mechanism. It is important to learn the most effective way to raise attendance so the reinforcement process reaches more individuals.

In situ assessment of cell proliferation at the invasive front of oral squamous cell carcinomas.

In oral squamous cell carcinoma (OSCC) the histopathological malignancy grading of the invasive front has been found to offer the most reliable prognostic parameter. In the present study we compared such tumour front grading of 100 OSCCs with the in situ growth fraction demonstrated by MIB1 immunostaining following wet autoclave antigen retrieval. MIB1 labelling indices (LIs) were estimated both at the invasive front and in the central parts of OSCCs using two different evaluation methods (overall and random counting) to investigate whether MIB1 LIs represent a possible biological background for the tumour front grading. Statistically highly significantly increased MIB1 LIs were found at the invasive tumour fronts with both counting methods compared with the centres of the same tumours. For LI estimation the classic overall counting procedure proved to be superior. However, in contrast to tumour front grading, MIB1 LIs revealed no correlation with the clinical outcome of the patients concerned. Our results demonstrate that the invasive tumour front of an OSCC is composed of (a) tumour subpopulation(s) with higher proliferative activity. However, determination of the proliferative activity by MIB1 of this tumour area offers no prognostic information.

Antihypertensive mechanism of amlodipine in essential hypertension: role of pressor reactivity to norepinephrine and angiotensin II.

Calcium entry blockade may affect the pressor reactivity to vasoconstrictors. The pressor response to norepinephrine and angiotensin II, as well as several other blood pressure modulating factors, were studied in normal subjects (n = 9) and patients with essential hypertension (n = 10) before and after 8 weeks of treatment with the long-acting dihydropyridine amlodipine. In control subjects, calcium entry blockade did not modify blood pressure, the pressor and aldosterone response to angiotensin II, the activity of the renin-angiotensin and sympathetic nervous systems, or urinary dinoprostone (prostaglandin E2) excretion; however, the pressor response to norepinephrine was significantly decreased (p less than 0.01). In patients with hypertension, amlodipine decreased blood pressure (p less than 0.01) and the pressor response to both norepinephrine and angiotensin II (p less than 0.01), without changes in body weight, plasma renin, angiotensin II and catecholamine levels, dinoprostone excretion, or aldosterone responsiveness to angiotensin II. These findings suggest that calcium entry blockade modifies sympathetic-dependent vasoconstriction in both normal subjects and in patients with hypertension. Angiotensin II pressor response may be selectively decreased in essential hypertension.