In situ hybridisation for the identification of Helicobacter pylori in paraffin wax embedded tissue

A method for identifying Helicobacter pylori using a non-isotopic in situ hybridisation technique is described. A probe generated by polymerase chain reaction (PCR) with primers directed against parts of the Helicobacter pylori 16SrRNA sequence was used. Paraffin wax embedded gastric biopsy specimens from patients with and without gastritis were hybridised with the probe, and the method was shown to be sensitive and specific for H pylori.

Mesenteric lipodystrophy

Three cases of mesenteric lipodystrophy with a wide range of clinicopathological features are reported. Mesenteric lipodystrophy may present as an acute abdomen or with non-specific upper abdominal symptoms. Routine biochemical and haematological investigations are within normal limits. Histological examination shows lipid-filled macrophages in sheets and bands with focal cyst formation. Mesenteric lipodystrophy is a rare condition. A firm diagnosis can be reached only by histological examination and a number of conditions need to be considered in the differential diagnosis.

Mucous metaplasia of the pleura

A case of mucous metaplasia of mesothelium in an 80 year old woman is described. Its cause is unknown, but it is important not to confuse it with secondary tumour.

Alpha-1 antitrypsin gene exon use in stimulated lymphocytes

AIMS

To investigate the expression of mRNA transcripts containing exon A or B in lymphocyte cultures.

METHODS

An in situ hybridisation technique, using synthetic, biotinylated oligonucleotide probes was deployed to allow the demonstration of exon A, exon B, or the normal hepatocyte message containing exon C.

RESULTS

Lymphocytes used the same alternative splicing technique as monocytes in the generation of their alpha-1 antitrypsin message. They also provided data on the frequency of exon A and B expression in cells from different subjects. Most circulating granulocytes failed to show the alpha-1 antitrypsin message, suggesting that this protein is synthesised in the marrow and represents a stored protein component in polymorph and circulating nuclear lymphocytes.

CONCLUSIONS

In situ hybridisation is a sensitive technique for the detection of individual gene exon use in cell populations. Lymphocytes show the same promoter use as that described for monocytes.

Alpha-1 anti-trypsin and CD30 expression occur in parallel in activated T cells

We have performed an immunohistochemical study of immunoblastic T cell lymphoma and enteropathy-associated T cell lymphoma for alpha-1 anti-trypsin and CD30. Cytoplasmic staining for alpha 1 anti-trypsin is present in the malignant cells in both types of T cell neoplasm which also express CD30, a marker of lymphoid activation. Peripheral blood T lymphocytes on stimulation with mitogen also show granular cytoplasmic expression of alpha 1 anti-trypsin. Time course studies show that this parallels the expression of CD30. Alpha 1 anti-trypsin expression appears therefore to be associated with activation in T cells. Further studies of sub-fractionated T lymphocytes in vitro suggest that the expression of alpha 1 anti-trypsin on activation is not restricted to an individual lymphocyte subset.