Brief communication The primate MHC contains sequences related to the fibroblast growth factor receptor gene family

We have cloned and sequenced a genomic region centromeric of the HLA-B locus from different MHC ancestral haplotypes. These haplotypes are associated with several diseases. The sequences were analyzed for coding potential and their relevance to disease associations were assessed with respect to the level of polymorphism. Analysis of sequences located approximately 25kb centromeric of HLA-B reveals the existence of fibroblast growth factor receptor related sequences. These sequences designated PERB1 (FGFR6 ) reveal 80% homology, at both nucleic acid and amino acid level, to the immunoglobulin domain 1 (Ig-1) of the human fibroblast growth factor receptor 3 ( FGFR3 ) gene. Amino acid comparison of the Ig-1 domain of PERB1 to those of other FGFR molecules indicates that PERB1 is more closely related to FGFR3 and FGFR5 than to FGFR1 , FGFR2 or FGFR4 . Genomic sequence analysis, however, reveals no consensus splice sites and indicates the existence of inframe premature stop codons in the putative coding sequences. The results suggest that these sequences may represent FGFR gene fragments existing within the central MHC. Sequence analysis of the Mhc in 6 chimpanzee and one orangutan indicates that the existence of PERB 1 predates the spe-ciation of the three species. The fact that the MHC contains a mixture of functional and nonfunctional (pseudo) genes suggests that a functional copy of PERB1 (FGFR6 ) may exist within or in close proximity to the MHC.     

In situ saphenous vein bypass grafts: angiographic evaluation and interventional repair of complications

In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications.     

A twin study of ethanol metabolism

Blood alcohol measurements were obtained for 206 pairs of twins who had ingested a standard dose of alcohol (0.75 g/kg body weight) and repeat measurements were obtained for 40 of these pairs on a second occasion. The repeatability of the peak blood alcohol concentration (BAC) was 0.66, that of the rate of elimination was 0.39, and that of the time to peak BAC was 0.27. Only a small portion of the nonrepeatable variance could be explained by measurement error or drinking experience. It is concluded that short-term environmental factors exercise considerable influence on alcohol metabolism, particularly in the absorption phase. All of the repeatable variance in peak BAC and rate of elimination was due to genetic factors. Only a small proportion of any of the genetic variance could be explained by individual differences in weight, adiposity, or lung function. Likewise, these three factors were unable to account for the fact that females had higher BACs than males during both absorption and elimination.This work was supported by a grant in aid from the Australian Associated Brewers.     

The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity

The integrity of sperm DNA is crucial for the maintenance of genetic health. A major source of damage is reactive oxygen species (ROS) generation; therefore, antioxidants may afford protection to sperm DNA. The objectives of the study were, first, to measure the effects of antioxidant supplementation in vitro on endogenous DNA damage in spermatozoa using the single cell gel electrophoresis (comet) assay and, second, to assess the effect of antioxidant supplementation given prior to X-ray irradiation on induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll centrifugation in the presence of ascorbic acid (300, 600 microM), alpha tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5, 10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand breakage was measured using the comet assay. Sperm DNA was protected from DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60 microM) and urate (400 microM). These antioxidants provided protection from subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or ascorbate and alpha tocopherol together induced further DNA damage. Supplementation in vitro with the antioxidants ascorbate, urate and alpha tocopherol separately has beneficial effects for sperm DNA integrity.