Immunophenotyping of acute non-lymphoblastic leukaemias

Using monoclonal antibodies specific for myelomonocytic cells, 40 non-lymphoblastic leukaemias were analysed applying immunostaining to cytospin preparations. Based on the reactivity patterns six groups of acute non-lymphoblastic leukaemias could be determined, mirroring the bimodal differentiation pathway of myelomonocytic cells. Comparative enzyme cytochemical analysis did not render a clear cut correlation and discrimination of the immunocytochemically defined groups. It is concluded that only the application of a broad panel of immunocytochemical and enzyme cytochemical methods allow a sound subdivision and diagnosis of acute non-lymphoblastic leukaemias.     

Conformational energy analysis of the chemotactic tripeptide formyl-Met-Leu-Phe and three analogs

Conformational energy analyses were carried out on the chemotactic tripeptide fMLF (CHO-Met-Leu-Phe) and three analogs fALF (CHO-Ala-Leu-Phe). fMF (CHO-Met-Phe), and MLF (H-Met-Leu-Phe). A near-folded or puckered conformation predominates in all four peptides. The calculated average end-to-end distance R of each of the peptides is 7.4 A, 7.6 A, 7.0 A, and 7.3 A, respectively (where bends have R less than or equal to 7 A and extended structures have R approximately 10.5 A). The puckered conformation calculated for fMLF is similar to that determined experimentally for fMLF in nonpolar solvents and in the protein receptor. The results suggest that maximum chemotactic activity of the peptides depends on a combination of the chemical structure (the presence of N-formyl-methionine) and backbone conformation (C7conformation of the first amino acid residue).     

Inv(14) with distal breakpoint in 14q32.1 in three cases of T cell lymphoma

Summary The distal breakpoint of inv(14) in T cell clones, established from patients with ataxia telangiectasia, lies outside the immunoglobulin heavy chain gene locus on 14q32.3, and more proximal to the centromere than the distal breakpoint of inv(14) in the T cell lymphoma cell line SUP-T1. We report 3 cases of T cell lymphoma cytogenetically showing the same type of inv(14) as the AT T cell clones. All 3 cases express a similar immunophenotype, which is that of peripheral T lymphocytes with phenotypic remnants of thymic or postthymic lymphoblasts. This finding provides evidence that this type of inv(14) is involved in the malignant transformation of mature T lymphocytes.     

Proffered papers 9.30–10.00 Monday 15 September 2003

Both the original Bethesda system and the current UK classifications of cervical cytology have proved robust but each has a major weakness in the area of abnormalities of uncertain significance. Cytologists recognize that sometimes it is simply impossible to differentiate between reactive and dyskaryotic material. For this reason, the Australian version of the Bethesda system introduced a new category of 'high grade inconclusive' with a recommendation for referral to colposcopy. Approximately 60% of such cases are found to have high grade lesions at colposcopy (Schoolland M, Sterrett G, Knowles S et al .). The present UK system even with the proposed changes requires of the pathologist, a decision as to whether such cases are probably high grade (=a report of moderate dyskaryosis) or not (= a report of borderline). This continues to ignore the fact that sometimes you just cannot tell, even on review. We have taken a consecutive series of 50 referral smears, reported as moderate dyskaryosis, where the histological outcome (by loop cone) is known. These cases were rescreened and then reviewed blind by a pathologist with extensive experience of the Australian NH & MRC modified Bethesda system. On review, the material was reclassified along NH & MRC lines. The results were compared with the biopsy findings in order to determine whether the category of 'inconclusive' might be of value in the context of the NHSCSP.     

Experimental pretransfer expansion of free-flap donor sites: II. Physiology, histology, and clinical correlation

There is a statistically significant increase in blood flow into expanded cutaneous and myocutaneous flaps in a pig model over controls. The vascular trees within flaps enlarge following expansion, and pronounced neovascularization is seen in the papillary dermis and capsular layers. Experimentally, there is differential thinning of all tissue layers except the epidermis. A successful clinical application of this technique, by free-tissue transfer of an expanded fasciocutaneous scapular flap, is described. The technique is applicable when altered flap size or contour is desired.     

Selection of a cold-adapted bacterium for bioremediation of wastewater at low temperatures

Amongst more than 1000 isolates collected in various cold environments, the strain Arthrobacter psychrolactophilus Sp 31.3 has been selected for its ability to grow and to produce exoenzymes at low temperatures, its inability to grow at 37°C, its non-halophilic character and its growth versatility on various media. This non-pathogenic strain displays a strong resistance to desiccation and storage at room temperature and is suitable for the production of freeze-dried bacterial starters. When grown in a synthetic wastewater at 10°C, the strain induces a complete clarification of the turbid medium and efficiently hydrolyses proteins, starch and lipids in the broth. Furthermore, this strain has a remarkable capacity to improve the biodegradability of organic compounds in wastewater as indicated by a BOD₅/COD ratio of 0.7.     

Conformational energy analysis of the pentapeptide Ac-Arg-Asn-Cys-Tyr-Asn-NMA from alpha 1-purothionin

Conformational energy analyses were carried out on the pentapeptide RNCYN (Ac-Arg-Asn-Cys-Tyr-Asn-NMA) and on related peptides. RNCYN is a highly conserved amino acid sequence in thionins and viscotoxins. The conformation of the pentapeptide was calculated to be an amphipathic alpha-helix, with the tyrosine and cysteine on the nonpolar side of the helix and the arginine and both asparagines on the polar side. Our results are inconsistent with the conformation determined using the Chou-Fasman prediction method, but are consistent with the conformation determined experimentally (using n.m.r.) for this pentapeptide sequence in alpha 1-purothionin.