Chemical modification of proteins by insertion of synthetic peptides using tandem protein trans-splicing

Manipulation of proteins by chemical modification is a powerful way to decipher their function. However, most ribosome-dependent and semi-synthetic methods have limitations in the number and type of modifications that can be introduced, especially in live cells. Here, we present an approach to incorporate single or multiple post-translational modifications or non-canonical amino acids into proteins expressed in eukaryotic cells. We insert synthetic peptides into GFP, NaV1.5 and P2X2 receptors via tandem protein trans-splicing using two orthogonal split intein pairs and validate our approach by investigating protein function. We anticipate the approach will overcome some drawbacks of existing protein enigineering methods.

Blood pressure values in healthy Malaysian children aged 6-12 years

Blood pressure examination was done manually in 1756 healthy school children aged 6-12 years. Korotkoff 1 represented the systolic blood pressure (SBP) and Korotkoff 5 was taken as the diastolic blood pressure (DBP). Blood pressure percentile charts were then drawn up based on age group and sex regardless of ethnicity. There was a significant correlation between both SBP and DBP to increasing height, weight and body mass index.

Diet, acetylator phenotype, and risk of colorectal neoplasia

BACKGROUND

Inherited or acquired differences in metabolic pathways that activate or inactivate dietary carcinogens may influence the risk of developing cancer. A polymorphism in N-acetyltransferase classified people into fast and slow acetylators. This enzyme catalyses the formation of mutagenic products from foodstuffs, especially cooked meat and fish. Some data suggest that fast acetylators are at higher risk of colorectal cancer. We have studied the adenoma and cancer risk in relation to meat intake and acetylator status.

METHODS

In a case-control study, we compared 110 patients with colorectal cancer, 89 patients with colorectal adenomatous polyps, and 110 controls. Acetylator status was assessed by the rate of acetylation of sulphamethazine given orally.

FINDINGS

The fast-acetylator phenotype was associated with odds ratios of 1.1 (95% Cl 0.6-2.1) and 1.8 (1.0-3.3) for adenoma and colorectal cancer, respectively. The highest risk occurred in the youngest tertile (< 64 years) of cases (2.5 [0.7-9.4] and 8.9 [2.6-30.4], respectively). There was no difference between the sexes. The risk of adenoma or cancer increased with increasing intake of meat in fast but not in slow acetylators: covariate-adjusted odds of disease over three levels of meat consumption were 2.1 (0.9-4.7) for adenoma, 1.7 (0.9-3.5) for cancer, and 1.9 (1.0-3.7) for all tumours.

INTERPRETATION

Our findings indicate that acetylator status modulates the risk of colorectal neoplasia associated with meat intake.

Glutathione concentrations and glutathione S-transferase activity in human colonic neoplasms

Tissue concentrations of glutathione (GSH) and the activity of glutathione S-transferases (GST) are relevant to the inactivation of a variety of xenobiotics including carcinogens and anti-neoplastic drugs. In this study, GSH concentrations and GST activity were determined in 25 adenomatous polyps removed at colonoscopy, and in cancer and uninvolved 'normal' mucosa from 58 operative specimens containing colon cancer. We also examined the relationship between GSH concentrations, GST activity and rates of cell proliferation as assessed by flow cytometry. Concentrations of GSH were significantly higher in adenomas (P = 0.001) and cancer (P = 0.001) than in uninvolved mucosa while GST activity was significantly higher in cancer (P = 0.007). There was a positive relationship between GSH concentrations and GST activity in adenomas (P = 0.001) but not in uninvolved mucosa (P = 0.06) or cancer (P = 0.4). Concentrations of GSH and GST activity were independent of results from flow cytometry. The higher concentrations of GSH in colonic neoplasms and the raised activity of GST in cancer may contribute to their resistance to anti-neoplastic drugs.

Fibreoptic bronchoscopy in rapid diagnosis of sputum smear negative pulmonary tuberculosis

We used fibreoptic bronchoscopy to investigate 70 patients with a suspected diagnosis of pulmonary tuberculosis, with histology of any visible lesion and examination of washings by Ziehl-Neelsen Stain and Lowenstein-Jensen culture, and in later cases BACTEC rapid culture technique. Thirty-five patients were considered to have tuberculosis in the light of the course of the illness and response to treatment. In these, chest radiology showed lung parenchymal lesions (LPL) with or without enlarged hilar or mediastinal glands in 18, and mediastinal gland enlargement (MGE) only in 17. In nine patients (four with MGE, five with LPL) the diagnosis of tuberculosis was confirmed by culture or histology of samples taken at bronchoscopy, and in five of these the diagnosis was available within 16 days of bronchoscopy. Of seven patients with positive cultures two had resistant organisms. There were no complications. Fibreoptic bronchoscopy provides early confirmation of diagnosis, and cultures to permit sensitivity studies, in a useful proportion of patients who traditionally present a considerable problem in diagnosis.

Upper anterior tooth mobility. Selected associations in untreated periodontitis

The relationship between buccolingual tooth mobility (TM) and other clinical parameters was studied in 124 upper anterior teeth in 21 patients with untreated periodontitis. Periapical long-cone radiographs were available for 74 teeth in the same population. TM was measured with Mühlemann's macroperiodontometer. Probing depths, attachment levels and bleeding were measured with a constant force probe. Bone levels were estimated from radiographs. Presence of occlusal contact was noted in the intercuspal position and excursive movements of the mandible. Attachment levels showed the highest correlation with TM, and radiographically estimated bone support was the next highest. Results varied according to tooth type: the attachment level of the lateral incisors showed the highest correlation with TM, while probing depths and proximal bone support showed lower associations with TM in all cases. In this population, no association was detected between the presence of occlusal contact and TM, or between inflammation and TM. Multiple and partial correlation analysis indicated that probing attachment level was the most important correlate of tooth mobility.

A five-year study of a haemophilia reference centre

Attendances at the Regional Haemophilia Reference Centre in the Edinburgh Royal Infirmary have been analysed over a period of five years from 1969 to 1973. Of 77 patients registered in 1969, 64 had haemophilia A (factor VIII deficiency) and 13 had haemophilia B (factor IX deficiency). In 1973 the numbers were 68 and 14 respectively. An increased attendance at the Centre from 123 in 1969 to 624 in 1973 was noted. This was due to patients reporting earlier and more frequently for outpatient treatment of haemarthroses which occurred with the greater availability of supplies of factor VIII. The number of admissions for inpatient treatment did not change significantly over the period. Haemarthrosis of the knee was the commonest dominant lesion. The amount of replacement therapy in the form of fresh frozen plasma, cryoprecipitate, antihaemophilic fraction, and factors II, IX, and X concentrate used in the Centre (ie, excluding that used for elective procedures) increased from 2704 donor units in 1969 to 8778 donor units in 1973, the main increase being in cryoprecipitate. The number of factor VIII units used per patient attending per year, for both elective and emergency treatment in haemophiliacs, is recorded and discussed as are its effects on the treatment patterns of patients and the implications for the future.