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Biomedical subjects

D J Hicks

Publications and source records attributed to D J Hicks.

29 records · Page 2Linked to original sources
PubMed1996

Differential growth inhibition by the aspirin metabolite salicylate in human colorectal tumor cell lines: enhanced apoptosis in carcinoma and in vitro-transformed adenoma relative to adenoma relative to adenoma cell lines.

Regular aspirin intake may reduce the risk of colorectal cancer by 50%. However, the mechanism of this chemopreventive effect is not known. The effect of the aspirin metabolite salicylate on the growth of human colorectal tumor cell lines was determined. Salicylate showed dose-dependent inhibitory effects on all of the cell lines (IC50, 1.65 +/- 0.36 to 7.38 +/- 1.08 mM), yet carcinoma and in vitro-transformed adenoma cell lines were more sensitive than adenoma cell lines. Salicylate caused all cell lines to accumulate in G0-G1 and induced apoptosis in carcinoma and in vitro-transformed adenoma cell lines but not in all adenoma cell lines. In those adenoma lines that did show salicylate-induced apoptosis, the extent was considerably less than that in the more transformed cell lines. The ability of salicylate to induce cell cycle arrest and apoptosis and, in particular, the increased sensitivity of cells at later stages of neoplastic progression may be mechanistically important in the chemopreventive action of aspirin toward colorectal cancer.

3T3 Cells↗
PubMed1995

Apoptosis in colorectal tumour cells: induction by the short chain fatty acids butyrate, propionate and acetate and by the bile salt deoxycholate.

The short chain fatty acids acetate, propionate and butyrate are produced when dietary fibre is fermented by the colonic bacteria. We have previously shown that sodium butyrate induces apoptosis in 3 colorectal tumour cell lines. We have extended our study to 3 adenoma and 4 carcinoma cell lines and investigated whether propionate and acetate also induce apoptosis. All 3 short chain fatty acids induced apoptosis at physiological concentrations, but of the 3, butyrate was the most effective. Since these fatty acids are produced as a result of bacterial fermentation of dietary fibre, this may in part explain the correlation between a high-fibre diet and low colorectal cancer incidence. Sodium butyrate induced apoptosis in all 7 of the cell lines studied; however, 2 of the 4 carcinoma cell lines (PC/JW/FI and S/KS/FI) were more resistant to butyrate-induced apoptosis than the 3 adenoma cell lines, suggesting that at least some carcinomas may evolve mechanisms to protect the cells from the induction of apoptosis. The bile acid deoxycholic acid has previously been reported as a possible tumour promoter in the large intestine and its levels are reduced by dietary fibre. Concentrations of between 10 nM and 0.1 mM had no effect on either the proliferation or apoptosis of colonic tumour cells in vitro. However, a significant induction of apoptosis was obtained at a concentration of 0.5 mM. These results may have significance for the aetiology of colorectal cancer.

Acetates↗
PubMed1980

Rape: sexual assault.

The Rape Treatment Center at Jackson Memorial Hospital, Miami, Florida, has cared for more than 5,000 victims of sexual assault since January, 1974. Forcible rape is a violent crime, and it is now generally accepted that rapists are sexual deviants. Few of the victims have serious physical injuries, but they all suffer psychological trauma that will affect their lives and the lives of those around them. These victims need expert medical care and psychological counseling if they are to adjust and re-enter society without major difficulties. It is essential that people dealing with these patients understand the dynamics of the situation so that they can care for them intelligently.

Adolescent↗
PubMed1978

Rape: sexual assault.

Forcible rape is a violent crime, as are all cases of sexual assault. In more than one-third of the cases, the victims are children, and a significant number of victims are elderly women. Although few of these victims have serious physical injuries, they all suffer psychological trauma that will affect their lives and the lives of those around them. All of these victims need medical care and psychologic counseling if they are to adjust and reenter society without difficulty.

Adolescent↗
PubMed1975

Qualitative and quantitative determinations of acid phosphatase activity in vaginal washings.

In the absence of spermatozoa, acid phosphatase activity (ACP) is an indicator of seminal fluid in cases of sexual assault. Both qualitative and quantitative ACP methods are employed by medical examiners. A large series of cases in which a qualitative test was employed is reported. A method for obtaining and handling specimens by vaginal washing was developed. This method provides suitable specimens for the examination for spermatozoa and the determination of ACP. Specimens obtained from 41 women provided examples of endogenous vaginal ACP and intravaginal seminal ACP. These specimens were used to evaluate qualitative and quantitative ACP methods for the detection of seminal ACP. Tartrate inhibition was not useful for separating endogenous vaginal and seminal ACP activities. The advantages of the method developed for specimen acquisition and of quantitative assays for ACP are discussed.

Acid Phosphatase↗
PubMedDate not supplied

Evaluation of zinc salt based fixatives for preserving antigenic determinants for immunohistochemical demonstration of murine immune system cell markers.

Conventional aldehyde based fixatives produce good morphological preservation. However, owing to their cross-linking mechanism of action, epitope loss may occur during fixation compromising the tissue for subsequent immunohistochemical (IHC) analysis. IHC is an important tool for characterizing antigen, cytokine and cytomorphological markers. The increasing use of mouse models for study of pathogenesis has highlighted the need to investigate alternative fixatives. In the study reported here, tissue samples from RIII mice with immune mediated lesions, Mycobacterium bovis infected mice, and uninfected control mice were fixed in either zinc salt fixative or buffered formalin, then tested for IHC using a panel of antibodies (CD3, CD4, CD8, CD45, CD54, F4/80, Interferon-gamma and MIP2). Zinc salt fixation preserved processing-sensitive murine cell markers (CD4, CD8 and CD54) and improved the intensity of immunolabeling for CD45, F4/80 and CD3. Buffered formalin failed to preserve any of the processing-sensitive murine epitopes for demonstration by subsequent IHC.

Animals↗