The fall and rise of Group A Streptococcus diseases.

Streptococcus pyogenes (or Group A Streptococcus, GAS) is a Gram-positive human pathogen responsible for a diverse array of superficial, invasive and immune-related diseases. GAS infections have historically been diseases of poverty and overcrowding, and remain a significant problem in the developing world and in disadvantaged populations within developed countries. With improved living conditions and access to antibiotics, the rates of GAS diseases in developed societies have gradually declined during the 20th century. However, genetic changes in circulating GAS strains and/or changes in host susceptibility to infection can lead to dramatic increases in the rates of specific diseases. No situations exemplify this more than the global upsurge of invasive GAS disease that originated in the 1980s and the regional increases in scarlet fever in north-east Asia and the UK. In each case, increased disease rates have been associated with the emergence of new GAS strains with increased disease-causing capability. Global surveillance for new GAS strains with increased virulence is important and determining why certain populations suddenly become susceptible to circulating strains remains a research priority. Here, we overview the changing epidemiology of GAS infections and the genetic alterations that accompany the emergence of GAS strains with increased capacity to cause disease.

Single-tube protocol for the extraction of DNA or RNA from paraffin-embedded tissues using a starch-based adhesive.

We describe a method using an inexpensive craft glue to routinely isolate specific areas of tissue as small as 1 mm2 from paraffin sections. The tissue may be digested to release nucleic acid suitable for PCR or reverse transcription PCR. The use of this procedure obviates the requirement for manual microdissection or ultraviolet light irradiation. Tissue remaining on the slide can be stained and analyzed, allowing the precision of the extraction to be determined. The slide can be stored as a permanent record of the material taken for analysis.

Treatment of stage D2 hormone refractory carcinoma of the prostate with 5-fluorouracil and Roferon-A: a Southwest Oncology Group study.

Based upon prior data suggesting that alpha-interferon possesses chemomodulatory activity, the Southwest Oncology Group conducted a study in which patients with hormone refractory, metastatic (stage D2) adenocarcinoma of the prostate were treated with 5-fluorouracil (5-FU) and Roferon-A. All patients had bidimensionally measurable disease. Treatment consisted of 5-FU 750 mg/m2/day by continuous i.v. infusion for 5 days with Roferon-A 9 million units subcutaneously ono days 1, 3 and 5. Roferon-A was continued three times weekly throughout treatment. Following a one week hiatus from 5-FU (week 2), 5-FU was continued at a dose of 750 mg/m2 i.v. bolus weekly. Nineteen patients were evaluable for toxicity. The most common toxicities were gastrointestinal and mucosal, hematologic and a flu-like syndrome. There were no deaths related to treatment. Among the 14 patients evaluable for response, the response rate was 0% (95% confidence interval, 0-18%). Thirteen of the 19 evaluable patients have died with a median survival of 9 months. The combination of 5-FU and Roferon-A does not have sufficient activity against advanced, hormone refractory prostate cancer to warrant further investigation.

The type IV Aeromonas pilus (Tap) gene cluster is widely conserved in Aeromonas species.

Nothing is known regarding the expression or function of the type IV Aeromonas pilus (Tap), which was recently identified following the cloning of a pilus biogenesis gene cluster (tapABCD). As a first step to determine the possible significance of Tap for Aeromonas virulence, the distribution of the tapA and tapD genes in hybridization group reference strains and clinical (n=42) and environmental (n=29) isolates was determined. Homologues of tapA and tapD were present in all strains tested. Hybridization with the tapA probe enabled us to differentiate between clinical and environmental isolates of A. veronii biovar sobria.

Aeromonas spp. possess at least two distinct type IV pilus families.

Type IV pili have been purified from strains of most of the Aeromonas species associated with gastroenteritis (A. veronii biovar sobria, A. hydrophila, A. trota and A. caviae). They appear to be a related family (molecular mass of pilin 19 to 23 kDa) with a tendency to bundle-formation. Hence, we have designated them 'bundle-forming pili' (Bfp). A type IV pilus biogenesis gene cluster (tapABCD) recently cloned from a strain of A. hydrophila, however, encoded a 17 kDa pilin which differed significantly in its N-terminal amino acid sequence from the Bfp pilins. This paper describes the cloning of part (tapA and approximately 20% of tapB) of a homologous pilin gene cluster from a Bfp-positive strain of A. veronii biovar sobria, and presents evidence that the entire pilin gene cluster (tapABCD) is present in this strain. The predicted N-terminal amino acid sequence of the pilin encoded by the A. veronii biovar sobria tapA differed markedly from the corresponding sequence of its Bfp pilin, and those of the Bfp purified from other Aeromonas strains and species. Probing with tapA and tapD genes showed that these Bfp-positive Aeromonas strains also possessed the Tap gene cluster. TapA proteins of A. veronii biovar sobria and A. hydrophila shared 53% identity and 63% homology. We conclude that Aeromonas species are potentially able to express at least two distinct families of type IV pili (Bfp and Tap).

Phase I-II study of 13-cis-retinoic acid in myelodysplastic syndrome.

Eighteen patients with myelodysplastic syndrome received 13-cis-retinoic acid (1.0-mg/kg/day starting dose with 0.5-mg/kg increment escalations) in a phase I-II trial. Two partial responses involving the erythroid series were observed in four patients with primary refractory anemia with ring sideroblasts. One of two patients with chronic myelomonocytic leukemia also achieved a partial response. No other responses were found in the remaining patients, which included eight with refractory anemia with excess blasts. In six patients drug toxicity necessitated termination of the trial. Four patients had unexpected drug-induced thrombocytopenia; three of these had low platelet counts before treatment. Two of the six patients had other toxic effects. Further studies are warranted to evaluate the effectiveness of 13-cis-retinoic acid in patients with refractory anemia with ring sideroblasts and chronic myelomonocytic leukemia. At moderate doses significant toxic effects, including thrombocytopenia, are not uncommon.

Investigation of the role of type IV Aeromonas pilus (Tap) in the pathogenesis of Aeromonas gastrointestinal infection.

Although there is substantial evidence that type IV pili purified from diarrhea-associated Aeromonas species (designated Bfp for bundle-forming pilus) are intestinal colonization factors (S. M. Kirov, L. A. O'Donovan, and K. Sanderson, Infect. Immun. 67:5447-5454, 1999), nothing is known regarding the function of a second family of Aeromonas type IV pili (designated Tap for type IV Aeromonas pilus), identified following the cloning of a pilus biogenesis gene cluster tapABCD. Related pilus gene clusters are widely conserved among gram-negative bacteria, but their significance for virulence has been controversial. To investigate the role of Tap pili in Aeromonas pathogenesis, mutants of Aeromonas strains (a fish isolate of A. hydrophila and a human dysenteric isolate of A. veronii bv. sobria) were prepared by insertional inactivation of the tapA gene which encodes the type IV pilus subunit protein, TapA. Exotoxic activities were unaffected by the mutation in tapA. Inactivation of tapA had no effect on the bacterial adherence of these two isolates to HEp-2 cells. For the A. veronii bv. sobria isolate, adhesion to Henle 407 intestinal cells and to human intestinal tissue was also unaffected. There was no significant effect on the duration of colonization or incidence of diarrhea when the A. veronii bv. sobria strain was tested in the removable intestinal tie adult rabbit diarrhea model or on its ability to colonize infant mice. Evidence was obtained that demonstrated that TapA was expressed by both Aeromonas species and was present on the cell surface, although if assembled into pili this pilus type appears to be an uncommon one under standard bacterial growth conditions. Further studies into factors which may influence Tap expression are required, but the present study suggests that Tap pili may not be as significant as Bfp pili for Aeromonas intestinal colonization.

Loss of heterozygosity on chromosome 2q: possibly a poor prognostic factor in head and neck cancer.

BACKGROUND: Loss of heterozygosity (LOH) correlates with inactivated tumor suppressor genes. The aim of this study was to see if LOH on chromosomes 2q, 3p, 5q, 9p, and 17p correlated with survival in early squamous cell carcinoma of the head and neck (SCCHN). METHODS: A case control study was performed. Ten patients with stage I or II tumors who ultimately died of their disease were identified and matched with suitable controls. None of the controls had a local recurrence and at time of last follow-up were alive with no evidence of disease or had died of an unrelated illness. The deoxyribonucleic acid (DNA) was extracted from paraffin blocks, and LOH studies were performed using microsatellite markers. RESULTS: The respective incidence of allelic loss for the index and control patients was as follows: chromosome 2q, 75% and 20% (p = .03); chromosome 3p, 71% and 57%, respectively (not significant); chromosome arm 5q, 30% and 25% (not significant); chromosome arm 9p, 71% and 73% (not significant); and chromosome arm 17p, 75% and 46% (not significant). Therefore, loss on chromosome 2q strongly correlated with poor survival (odds ratio = 10.4). CONCLUSION: Loss of heterozygosity on chromosome 2q may correlate with a poor prognosis in early-stage SCCHN.