Cystic fibrosis transmembrane regulator gene mutations in Bahrain.

A genotypic study was undertaken to characterize the cystic fibrosis transmembrane regulator gene mutations (CFTR) in the Bahraini cystic fibrosis (CF) population using a polymerase chain reaction-based direct gene test to search for 15 common CF mutations amongst Arabs. During the period October 2000 to May 2001, 19 patients (12 males and seven females; aged at time of study between 4 months and 14 years with a mean age of 5.4 +/- 4.3 years) from 13 families were recruited in the study. Patients were diagnosed as having CF, based on a typical clinical picture and sweat chloride levels > 60 mmol/l and were screened for CFTR mutations. The rate of consanguinity among the families was 77 per cent. Eight mutations were detected in 21 of the 26 alleles examined. The overall detection rate was approximately 81 per cent. The allele frequency of the eight mutations was estimated to be approximately 73 per cent. There was no specific phenotypic pattern that correlated with a specific genotype. All families except two were of Bahraini origin. Of the eight mutations detected, four were common among Bahrainis (2043delG > 548A --> T > 4041C --> G = deltaF508, in order of decreasing frequency), accounting for 66 per cent of the Bahraini CF alleles. However, we also detected four different heterozygous mutations, namely: 1161delC, 1756G -->T, 3120 + 1G --> A, and 3661A --> T, accounting for 16 per cent of the Bahraini CF alleles.

Fructosamine in HbS and G6PD-deficient Saudi Arabs in the Eastern Province of Saudi Arabia.

Plasma fructosamine, total proteins and albumin were estimated in a group of 77 sickle cell anaemia and 32 glucose-6-phosphate dehydrogenase (G6PD)-deficient Saudi Arabs and the results compared with those obtained in a group of 30 normal controls. The mean values of fructosamine in the sickle cell anaemia and G6PD-deficient patients were not statistically different from those of the controls. The mean values of the total proteins and albumin were also not significantly different from those of the normal group. It is concluded that fructosamine level is not affected by sickle cell anaemia and G6PD deficiency, and provides a useful tool for monitoring diabetic patients in regions with high prevalence of haemoglobinopathies and G6PD deficiency.

Morphological transformation and chemotactic migration of fibroblasts by TGF-beta-related 25Kd polypeptide.

25Kd is a polypeptide molecule that shows many characteristics of the transforming factor type beta. We have studied the ability of 25Kd to induce morphological changes and also chemotactic migration of normal and transformed fibroblasts. It was found that normal cells exposed to 25Kd show an aberrant morphology while transformed cells are no longer randomly distributed over the culture dish but instead organize into clusters. In vitro, 25Kd is a potent chemoattractant for fibroblasts at doses ranging from 0.1-5ng/ml. Complete inhibition of chemotaxis was achieved in the presence of anti-25Kd antibodies.

Isolation and characterization of 25Kd fibronectin-binding growth factor.

A high recovery protocol was devised for the isolation of a 25Kd protein in a pure form from bovine serum using successive affinity and gel permeation chromatography techniques. Structural characterization of the resulting isolate shows that it is a Mr 25Kd polypeptide consisting of two chains held together with disulphide bonds. 25Kd is an acid- and heat-stable molecule, requiring the disulphide bonds for full activity. The biological activity of 25Kd is in a latent form that requires acidification, alkinisation or exposure to urea for activation. When tested on different cell lines for mitogenicity, 25Kd shows a 7.2- and a 3-fold increase over basal at 50ng/ml with CH23 and SV3T3 fibroblasts respectively. However, it shows a considerable inhibition (up to 90% at 10ng/ml with 3T3 cultures. Active 25Kd stimulates colony formation on soft agar of CH23, 3T3 and SV3T3 which requires the presence of 5ng/ml epidermal growth factor (EGF). The concentration of purified 25Kd required to elicit a half-maximal response for formation of colonies is 0.1-5ng/ml when assayed in the presence of 5ng/ml EGF. Both anti- 25Kd antibodies and synthetic pentapeptide Gly-Arg-Gly-Asp-Ser inhibit colony-stimulating activity of 25Kd. The finding that 25Kd is not a fibronectin fragment provides more supporting evidence that 25Kd is a serum growth factor. The structural properties, chromatographic behaviour, immunological and biological activities of 25Kd suggest a close relationship to transforming growth factor type beta (TGF-B).