The effect of temperature on the fine structural characteristics of cotton-fibre – a small-angle X-ray scattering investigation using correlation functions. Erratum

Owing to a typsetting error, the heading ER was wrongly mis-set as Eg in Table 1 of the paper by Misra, Bisoyi, Khan & Patel [J. Appl. Cryst. (1991), 24, 712–714]. The correct table is given.

T-U wave alternans. A case report and review of the literature

A patient with severe hypertension, hypokalemia and marked T-U wave alternans on electrocardiogram is reported for its rarity. Relevant literature is reviewed. Recent data indicate that electric alternans is related to changes in action potential configuration, and that it may be a marker of cardiac electrical instability.

Metastatic angiosarcoma of the ovary

A case of metastatic angiosarcoma of the ovary, complicated by disseminated intravascular coagulation, is described. The tumour was diagnosed by histopathologic examination and immunohistochemical studies. Angiosarcoma of the ovary, although extremely rare, appears to be a highly malignant neoplasm with an aggressive course and effective therapy is unknown.

Drug-induced colonic pseudo-obstruction. Report of a case

Colonic pseudo-obstruction may have many possible causes. Some of these are well described and pose no diagnostic problems. Drug-related colonic pseudo-obstruction remains underreported, but is of importance in modern society where drugs are endemically abused. This case highlights the importance of drugs in altering colonic motility and emphasizes the nonsurgical management of this condition.

The management of postoperative chylous ascites. A case report and literature review

Chylous ascites remains rare as a complication of surgical intervention. Although therapeutic manoeuvres to control chylous ascites have been developed over the past 20 years, its pathophysiology is poorly understood. Conservative approaches involving dietary restriction of long-chain triglycerides and salt, together with multiple paracenteses, are still the therapies of choice. Persistent chylous ascites may be treated surgically by ligation of leaking lymphatics or implantation of a peritoneovenous shunt once the lymphatic anatomy has been defined by preoperative investigations. We report a case of chylous ascites developing after laparotomy and duodenotomy for obscure gastrointestinal bleeding, which did not respond adequately to medical therapy and was successfully managed by the insertion of a peritoneovenous shunt.

Efficient synthesis of enzymatically active calf chymosin in Saccharomyces cerevisiae

We have constructed a high-efficiency expression vector to direct the synthesis of heterologous polypeptides in yeast. The vector is termed a sandwich expression vector as the heterologous gene is inserted between the 5' and 3' control regions of the efficiently expressed yeast PGK gene. We have used this vector to direct the expression of three derivatives of the calf chymosin cDNA gene; preprochymosin, prochymosin and chymosin. Prochymosin is synthesised to at least 5% of total yeast-cell protein and furthermore, it can be readily activated to produce an enzyme which has milk-clotting activity.

Lectin-like polypeptides of P. falciparum bind to red cell sialoglycoproteins

Attempts to control human malaria by immunological means could be compromised by antigenic variability within and between different strains of malarial parasites1. A useful alternative approach might be to block parasite antigens which are important in the mechanisms of invasion of red cells. As the major human parasite Plasmodium falciparum is highly specific for human red cells, isolation of the proteins involved in the recognition of red cells by this parasite might be of particular value. Recent studies suggest that the major red cell sialoglycoproteins (SGPs), glycophorins A, B and possibly C, may carry the sites recognized by the parasite2-4. Furthermore, because certain carbohydrates present on SGPs such as N-acetylglucosamine are able to block invasion by the parasite5, they may be involved in the initial interaction between parasite and red cell. We have now identified parasite proteins which bind to SGP or N-acetylglucosamine on Sepharose 4B columns. Three proteins, of molecular weights (MWs) 140,000 (140K), 70K and 35K, seem to be specifically bound by N-acetylglucosamine.

Chemical synthesis and cloning of a gene for human beta-urogastrone

A DNA duplex coding for the 53 amino acids of human beta-urogastrone has been synthesised. Computer assisted design of the gene included restriction endonuclease sites for plasmid insertion, a termination codon and two triplets coding for lysine at the 5'-end of the structural gene. The synthesis involved preparation of 23 oligodeoxyribonucleotides by phosphotriester procedures coupled to rapid HPLC techniques. The gene was constructed in two halves by enzymatic ligation of the oligonucleotides and cloned into a specially constructed chimeric plasmid vector. Escherichia coli K12 MRC8 was transformed by the plasmid and clones containing the full gene sequence were isolated and characterised.

The expression in E. coli of synthetic repeating polymeric genes coding for poly(L-aspartyl-L-phenylalanine)

Two dodecadeoxynucleotides of defined sequence have been synthesised by phosphotriester methodology. They can be polymerised to give a double stranded DNA which codes, when read in the correct phase, for the repeating dipeptide poly(aspartyl-phenylalanine). This polymeric DNA has been cloned in E. coli K12 using as vector a plasmid having a controllable bacterial promoter upstream of the insertion site. Clones containing genes coding for up to 150 repeats of (aspartyl-phenylalanine) have been isolated and characterised. The polymeric inserts appear to be stable over many generations and are expressed in E. coli under the control of the bacterial promoter, to give a polymer of phenylalanine and aspartic acid which may be broken down enzymically to yield aspartyl-phenylalanine.

Juvenile colonic polyposis with villous adenoma and retroperitoneal fibrosis: Report of a case

A 25-year-old Nigerian black woman was found to have polyps involving the rectum, rectosigmoid, and sigmoid colon on air-contrast barium-enema examination. Resection of a segment of sigmoid colon revealed numerous polyps that were predominantly of the juvenile type, in keeping with the diagnosis of juvenile polyposis of the colon. This case is unusual because of the coexistence of retroperitoneal fibrosis with juvenile polyposis of the colon. In addition, one of the colonic polyps was a villous adenoma. The implications these findings are discussed in relation to polyposis syndromes reported previously.