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Biomedical subjects

R Harvie

Publications and source records attributed to R Harvie.

6 recordsLinked to original sources

Detection of mRNA by in situ hybridisation and in northern blot analysis using oligodeoxynucleotide probes labelled with alkaline phosphatase.

AIMS: To assess whether a reduction in intensity of signal observed using an alkaline phosphatase labelled oligodeoxynucleotide probe could be explained on the basis of procedural steps rather than reduced sensitivity. METHOD: Signal intensity was assessed on in situ hybridisation for pro-opiomelanocortin (POMC) mRNA in rat pituitary and for somatostatin mRNA in human pancreas and in northern blot analysis for POMC mRNA in the presence and absence of formamide. The direct effects of formamide on the alkaline phosphatase detection step were assessed using histochemical enzyme detection in rat kidney. RESULTS: All signals were reduced in systems containing formamide. CONCLUSIONS: In the absence of formamide clear, strong signals for specific mRNAs can be obtained by in situ hybridisation and northern blot analysis using oligodeoxynucleotide probes directly labelled with alkaline phosphatase. Formamide seems to inhibit the activity of alkaline phosphatase.

Alkaline Phosphatase

Detection of mRNA for ribosomal phosphoprotein P2 in normal colon and colonic tumours by in situ hybridization.

We have localized the mRNA for the ribosomal phosphoprotein P2, a putative metastasis-related sequence, in normal colon and colonic carcinomas by in situ hybridization, using an oligonucleotide probe end-labelled with digoxigenin. The mRNA was identified in normal colonic epithelial cells, the intensity of the signal being greater in cells at the base of the crypts compared with those on the surface. A strong positive signal was also seen in plasma cells, in fibroblasts in granulation tissue, in ganglion cells, and in hepatocytes. A positive signal was identified in all 16 primary colonic tumours studied and in 7 hepatic metastases. In contrast to previous studies based on Northern blot analysis, we were unable to demonstrate increased expression in metastases as compared with primary tumours, nor could we demonstrate any increased expression in primary tumours which were associated with distant metastases.

Adenocarcinoma

Detection of messenger RNA using a digoxigenin end labelled oligodeoxynucleotide probe.

A synthetic oligodeoxynucleotide sequence complementary to the mRNA for the adrenocorticotrophin (ACTH) precursor pro-opiomelanocortin (POMC) was end labelled using digoxigenin. The probe was used to detect POMC mRNA both on nitrocellulose filters and by non-isotopic in situ hybridisation (NISH) in tissue sections. Digoxigenin was identified using anti-digoxigenin alkaline phosphatase. The model system examined was the rat pituitary gland. Removal of both adrenal glands and dexamethasone administration were used to change the concentrations of POMC mRNA in the rat anterior lobe. The labelled probe reacted with a single band of appropriate molecular weight in Northern blot analysis. The distribution of signal in tissue sections and the changes induced by experimental manipulation were as predicted. The results indicate that this method of NISH will prove useful in the detection of specific messenger RNAs in tissue sections of buffered, formalin fixed, paraffin wax embedded material.

Animals

Serum galactosyltransferase isoenzyme patterns of cancer patients with liver involvement.

The level of galactosyltransferase activity was measured in the serum of 220 patients with a variety of solid tumours. There was a significantly greater proportion of patients with elevated galactosyltransferase in the group with metastatic disease (43%) than for the group with localised disease (16%). Galactosyltransferase was elevated in 69% of patients with liver metastasis compared to 32% of patients with metastatic disease at sites other than liver and this difference was also significant. High resolution agarose isoelectric-focusing was used to determine the 'isoenzyme' pattern of serum galactosyltransferase of 6 patients with liver metastasis and 2 patients with primary hepatoma and these were compared to those of 6 patients with similar primary tumours without liver involvement. There were no qualitative differences in the patterns from the two groups. The average peak height for each of the 19 peaks of activity identified was generally higher in the group with liver involvement, except for those peaks known to contain little or no attached sialic acid. Liver involvement appears not to contribute in any specific way to the altered pattern of serum galactosyltransferase often seen in patients with solid tumours. The tumour rather than the liver is therefore the most likely source of these alterations.

Carcinoma, Hepatocellular

The heterogeneity and acceptor specificity of human serum galactosyltransferase.

Human serum was fractionated by high resolution agarose isoelectricfocusing and the galactosyltransferase activity profile was determined using the ovalbumin, mucin, glucose and N-acetylglucosamine acceptor assays. The four acceptors gave very similar activity profiles. There were minor quantitative differences in some of the 12 or more peaks of activity detected and the only qualitative difference between them was a minor peak at pH 3.90 (2% of the total activity) which reacted only with the mucin acceptor. This suggests that most of the isoenzymes of human serum galactosyltransferase have broad and similar acceptor specificities and that the heterogeneity seen in serum cannot be accounted for by acceptor-specific forms of the enzyme.

Galactosyltransferases