Complete genome sequence and analysis of Wolinella succinogenes

To understand the origin and emergence of pathogenic bacteria, knowledge of the genetic inventory from their nonpathogenic relatives is a prerequisite. Therefore, the 2.11-megabase genome sequence of Wolinella succinogenes, which is closely related to the pathogenic bacteria Helicobacter pylori and Campylobacter jejuni, was determined. Despite being considered nonpathogenic to its bovine host, W. succinogenes holds an extensive repertoire of genes homologous to known bacterial virulence factors. Many of these genes have been acquired by lateral gene transfer, because part of the virulence plasmid pVir and an N-linked glycosylation gene cluster were found to be syntenic between C. jejuni and genomic islands of W. succinogenes. In contrast to other host-adapted bacteria, W. succinogenes does harbor the highest density of bacterial sensor kinases found in any bacterial genome to date, together with an elaborate signaling circuitry of the GGDEF family of proteins. Because the analysis of the W. succinogenes genome also revealed genes related to soil- and plant-associated bacteria such as the nif genes, W. succinogenes may represent a member of the epsilon proteobacteria with a life cycle outside its host.     

Transmission and immunopathogenesis of FIV in cats as a model for HIV

The feline immunodeficiency virus (FIV) model provides a system to study lentivirus transmission, virus kinetics, pathogenesis, host responses, and immune dysfunction in a natural, out-bred host, under controlled conditions with specific-pathogen-free animals. The diversity of primary FIV strains can be exploited to mirror the range of disease manifestations associated with HIV infection. FIV is infectious via intravenous, intraperitoneal, intradermal, or subcutaneous injection as well as by atraumatic instillation onto the oral, vaginal, or rectal mucosa. Together, these features allow investigators to model specific aspects of HIV infection in a highly relevant and relatively inexpensive animal model. Well-developed areas of the FIV model include: (1) transmission of cell-associated as well as cell-free virus; (2) mucosal infectivity and immunopathogenesis; (3) vertical transmission; (4) acquired immunodeficiency including defects of the innate immune system; (5) thymic dysfunction; (6) neurotropism and neuropathogenesis; (7) host-virus interactions and the role of specific gene products; (8) efficacy of antiviral therapy; and (9) efficacy and immune correlates of experimental vaccines. This review will encompass areas specific to transmission and immunopathogenesis.     

Sphingosine-1-phosphate and its potentially paradoxical effects on critical parameters of cutaneous wound healing

The sphingolipid metabolite sphingosine-1-phosphate has emerged as a new bioactive molecule involved in the regulation of cell growth, differentiation, survival, and chemotaxis as well as angiogenesis and embryogenesis. These effects are mediated either via G-protein-coupled receptors or through intracellular actions. The most prominent sources of sphingosine-1-phosphate are human platelets suggesting its potential role in wound healing. In agreement with a positive function on reconstruction of wounded skin, we identified sphingosine-1-phosphate as a potent chemoattractant for keratinocytes as well as an activator of extracellular matrix production by fibroblasts. An unexpected finding is a strong cell growth arrest of keratinocytes after exposure to sphingosine-1-phosphate, as keratinocyte proliferation is critical for re-epithelialization of the wound. Most interestingly, the anti-proliferative effect of sphingosine-1-phosphate is not a result of cytotoxicity or apoptosis as sphingosine-1-phosphate even protects these cells from programmed cell death. Moreover, sphingosine-1-phosphate enhances differentiation of keratinocytes. To investigate further by which signaling pathway cell growth inhibition is mediated expression of the mRNA of all sphingosine-1-phosphate receptors (S1P1-5) was identified. 1 (Edg 1), 2 (Edg 5), 3 (Edg 3), 4 (Edg 6), and 5 (Edg 8) mRNA in keratinocytes was identified. As demonstrated in guanosine 5-[gamma-35S] triphosphate-gammaS binding assays, these G-protein-coupled receptors are functional at nanomolar concentrations. As the anti-proliferative effect of sphingosine-1-phosphate is only partially inhibited in the presence of pertussis toxin, it was investigated if intracellular actions are also involved. Microinjections of sphingosine-1-phosphate in keratinocytes also reduce proliferation suggesting that both sphingosine-1-phosphate receptors as well as intracellular actions mediate sphingosine-1-phosphate- induced cell growth arrest.     

Melorheostosis with ipsilateral nevus sebaceus (didymosis melorheosebacea)

We report an unusual case of unilateral melorheostosis and ipsilateral extensive sebaceous nevus. Because the two conditions affected the same side of the body, we hypothesize that they originated from a common genetic mechanism. The temporal and spatial co-occurrence may represent a further example of non-allelic didymosis (twin spotting). The embryo would carry two different recessive mutations at one gene locus or at linked loci on either of a pair of homologous chromosomes. Postzygotic recombination occurring during early embryonic development would result in two different populations of cells homozygous for either mutation. If this concept holds true, the present case may be described as " didymosis melorheosebacea ".     

Transurethral microwave therapy in 200 patients with a minimum followup of 2 years: urodynamic and clinical results

PURPOSE: We investigated the long-term efficacy of the second generation Targis thermotherapy device (Urologix, Inc., Minneapolis, Minnesota) for decreasing outflow obstruction caused by benign prostatic hyperplasia. MATERIALS AND METHODS: At a minimum followup of 24 months 200 patients with bladder outlet obstruction documented on urodynamics and cystoscopy document with preserved detrusor function underwent transurethral microwave therapy while under local anesthesia. In 45% of cases the general American Society of Anesthesiologists health score was 3 or greater. RESULTS: After a median observation time of 42 months (range 2 to 72) 43 patients (22%) who required additional treatment (repeat thermotherapy, transurethral prostate resection or permanent cystostomy) were excluded from further analysis, as were 15 (7.5%) who died of causes unrelated to treatment during followup and 13 (6.5%) who were lost to followup or refused followup investigations. In the 162 patients evaluated 6 months after treatment the median International Prostate Symptom Score decreased from 23 points (range 10 to 34) before treatment to 3 (range 0 to 21) and remained stable at 12 and 24 months. Median maximum flow increased from 6 ml. per second (range 1 to 15) before treatment to 14.5 (range 4 to 50) 6 months after treatment and remained stable at 12 and 24 months. Median post-void residual urine volume decreased from 170 ml. (range 35 to 720) before treatment to 17 (range 0 to 327) after 6 months and then remained unchanged. Urodynamic evaluation in the 162 patients after 6 months showed a decrease from pretreatment median detrusor opening pressure of 87.5 to 53 cm. water. Median detrusor pressure at maximum flow decreased from 86 to 58 cm. water 6 (p <0.0001). At the 24-month followup 59 of the 129 evaluable patients agreed to undergo repeat urodynamic evaluation. Pressure flow analysis in these 59 cases revealed a decrease in median minimal urethral opening pressure from 70 to 40 cm. water at 6 months and to 38 cm. water at 24 months (p <0.0001). Median detrusor pressure at maximum flow decreased significantly from the pretreatment value of 86 to 55 cm. water at 6 months and 58 cm. water at 24 months (p <0.0001). CONCLUSIONS: In patients with a good initial response to treatment, which is achieved in approximately 80%, transurethral microwave therapy provides excellent long-term subjective and objective results. Improved urinary flow, decreased post-void residual urine volume and urodynamic parameters remain stable at 2 years. Transurethral microwave therapy with second generation microwave equipment did not compromise any conventional treatment needed in the 22% of patients who were nonresponders at 6 months.     

The effects of hydroxyethyl starches on intracellular calcium in platelets

Hydroxyethyl starch (HES) solutions impair platelet function. To determine whether this effect is achieved through interference of HES with intracellular activation processes, in which calcium is the key second messenger, we evaluated the agonist-induced increase of the cytoplasmic calcium concentration in the presence of HES of different molecular weights. Aliquots of citrated whole blood of 12 volunteers were incubated in vitr. with saline, HES 450 (molecular weight in kilodalton), HES 130, and HES 70, resulting in 20% hemodilution. An undiluted sample served as control. The samples were stained with Fluo-3 as the calcium-sensitive fluorescent probe with subsequent flow cytometric analysis. After determination of a baseline, platelets were activated with thrombin receptor activator peptide 6. Platelet activation with thrombin receptor activator peptide 6 resulted in a fast increase in fluorescence (approximately eightfold), representing intracellular calcium mobilization. None of the tested HES solutions exerted a statistically significant effect on the cytoplasmic calcium concentration compared with samples that were incubated with saline or that remained undiluted. These results indicate that the known inhibiting effect of HES on platelets is not achieved through interference with intracellular activation processes. IMPLICATIONS: Hydroxyethyl starch does not exert its known inhibitory effect on platelet function by interfering with intracellular activation processes.