Regulation and regulatory role of gamma-carboxyglutamic acid containing clotting factors

Several investigators have recently reported that significant numbers of appropriately adapted mutants can be induced in bacterial and yeast strains by exposing stationary phase cells to specific environmental challenges. The resulting mutants are said to be both selection-induced and demonstrably non-random in origin; if this interpretation is correct, it is in direct conflict with the conventional neo-Darwinian view, which is that spontaneous mutants are truly random in origin and arise without the intervention of any overtly adaptive forces. We believe that there are alternative ways of accounting for the appearance of many (and probably all) of the additional mutants which proponents of the adaptive mutation theory claim are observed only after they applied the appropriate selective pressure. Having reviewed the available evidence, we consider that most (if not all) of the sorts of mutants which are said to have been induced following exposure of stationary-phase cells to intense selective pressure are equally likely to have been generated during the operation of certain well-known, conventional (and essentially random) cellular DNA repair processes. Evidence in support of our view can be found in the mainstream literature on the origins of spontaneous mutations. We also note that some of the molecular models which have recently been proposed to explain the production of selection-induced mutations preferentially (or even only) in genes of adaptive significance may turn out to be of considerable interest in their own right, even although the mutants whose origins they were intended to explain may turn out to have arisen in a manner which is totally independent of the conditions used for their selection.     

Safety of a temperature-sensitive clone of Mycoplasma synoviae as a live vaccine

A temperature-sensitive (ts+) clone derived from the Australian Mycoplasma synoviae (MS) field isolate 86079/7NS was produced by chemical mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine and assessed for safety as a live vaccine. This clone, designated MS-H, was assessed for pathogenicity in three different models with air sac lesions as the criterion. No air sac lesions were observed when MS-H was administered to specific-pathogen-free hybrid white leghorn (HWL) chickens by eyedrop at 10 times the normal dose or directly into the thoracic air sacs or as an aerosol administered to specific-pathogen-free Webster white leghorn chickens with concurrent intratracheal T-strain infectious bronchitis virus (IBV). MS-H did not revert to virulence or lose the ts+ phenotype when passaged through five in vivo and 10 in vitro passages. No adverse effects were seen when HWL chickens were vaccinated concurrently with MS-H and combinations of Mycoplasma gallisepticum ts-11 vaccine, IBV vaccine, and infectious laryngotracheitis virus vaccine. Lateral transmission of MS-H was found to occur when vaccinated HWL chickens were mixed with unvaccinated chickens 2 wk after vaccination. At 1 wk after mixing, one out of two unvaccinated chickens had seroconverted to MS and was culture positive for MS. At 2 wk after mixing, both contact chickens were positive for MS by culture and serology.     

The chronic non-healing wound: how to make it better

Chronic wounds are a commonly encountered problem. An understanding of their aetiology, combined with a systematic approach to their management, is fundamental to achieving an optimal environment for healing to take place.     

Periurethral fat injection in the treatment of recurrent genuine stress incontinence

A benign, transient proliferation of atypical lymphocytes and a monoclonal rearrangement of the T-cell receptor beta (TRB) locus was found in a 60-year-old woman who presented with low-grade fever, anorexia and fatigue. A marked and transient atypical lymphocytosis (white blood cell count 90.5 x 10(9)/l) with CD8 surface antigen improved without specific treatment. Although tests for IgM antibodies to hepatitis A, varicella zoster, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) were all negative, a monoclonal gene rearrangement of TRB locus was observed in the DNA of the proliferated atypical lymphocytes by Southern blotting. The clonal rearrangement and the atypical lymphocytes disappeared after 14 d, and the patient has remained well for 7 years. These results suggest that monoclonal proliferation of CD8 lymphocytes can occur based on a non-neoplastic aetiology.     

Enhanced specificity of truncated transmembrane protein for serologic confirmation of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infections by western blot (immunoblot) assay containing recombinant envelope glycoproteins

Immunoassays based on the highly immunogenic transmembrane protein of human T-cell lymphotropic virus type 1 (HTLV-1) (protein 21c) are capable of detecting antibodies in all individuals infected with HTLV-1 and HTLV-2. However, because of antigenic mimicry with other cellular and viral proteins, such assays also have a large proportion of false-positive reactions. We have recently identified an immunodominant epitope, designated GD21-I located within amino acids 361 to 404 of the transmembrane protein, that appears to eliminate such false positivity. This recombinant GD21-I protein was used in conjunction with additional recombinant HTLV type-specific proteins and a whole virus lysate to develop a modified Western blot (immunoblot) assay (HTLV WB 2.4). The sensitivity and specificity of this assay were evaluated with 352 specimens whose infection status was determined by PCR assay for the presence or absence of HTLV-1/2 proviral sequences. All HTLV-1-positive (n = 102) and HTLV-2-positive (n = 107) specimens reacted with GD21-1 in the HTLV WB 2.4 assay, yielding a test sensitivity of 100%. Furthermore, all specimens derived from individuals infected with different viral subtypes of HTLV-1 (Cosmopolitan, Japanese, and Melanesian) and HTLV-2 (IIa0, a3, a4, IIb1, b4, and b5) reacted with GD21-I in the HTLV WB 2.4 assay. More importantly, HTLV WB 2.4 analysis of 81 PCR-negative specimens, all of which reacted to recombinant protein 21e in the presence or absence of p24 and p19 reactivity in the standard WB assay, showed that only two specimens retained reactivity to GD21-I, yielding an improved test specificity for the transmembrane protein of 97.5%. None of 41 specimens with gag reactivity only or 21 HTLV-negative specimens demonstrated reactivity to GD21-I. In an analysis of additional specimens (n = 169) from different geographic areas for which PCR results were not available, a substantial increase in the specificity of GD21-I detection was demonstrated, with no effect on the sensitivity of GD21-I detection among specimens from seropositive donors. Thus, the highly sensitive, GD21-I-based HTLV WB 2.4 assay eliminates the majority of false-positive transmembrane results, thereby increasing the specificity for serologic confirmation of HTLV-1 and HTLV-2 infections.