Estrogen accelerates cutaneous wound healing associated with an increase in TGF-beta1 levels.

The cellular and molecular mechanisms underlying the effects of aging on human cutaneous wound healing are poorly understood, and the possible role of reproductive hormones in this process has never been investigated. We report that aging in healthy females was associated with a reduced rate of cutaneous wound healing, but an improved quality of scarring both microscopically and macroscopically, and with reduced levels of transforming growth factor-beta1 (TGF-beta1) immunostaining and steady-state mRNA in the wound. These age-related changes were reversed by the systemic administration of hormone replacement therapy (HRT). Moreover, ovariectomized young female rodents exhibited a marked delay in repair of acute incisional wounds, which was reversed by the topical application of estrogen. The cellular mechanism underlying these changes appears to involve an estrogen-induced increase in latent TGF-beta1 secretion by dermal fibroblasts. These results suggest that both the rate and quality of wound healing depend on reproductive hormone levels.

Comparison of early postoperative rehabilitation outcome following total knee arthroplasty using different surgical approaches and instrumentation.

PURPOSE: To assess early postoperative rehabilitation outcome following computer-assisted total knee arthroplasty (TKA) or standard instrumentation TKA using a medial parapatellar or subvastus approach. METHODS: A prospective controlled trial of 70 consecutive patients undergoing TKA with a low contact stress rotating platform prosthesis was conducted. Patients were randomised to receive surgery with either computer navigation or standard instrumentation. A medial parapatellar or subvastus approach was used according to the surgeons' preference. Outcome measures included preoperative knee function, intra-operative factors, and postoperative rehabilitation. RESULTS: Duration of surgery was significantly longer when using computer navigation; however, operating time decreased with greater experience. A higher incidence and duration of early postoperative quadriceps dysfunction was associated with computer-assisted TKA through the medial parapatellar approach than through the subvastus approach or TKA performed with standard instrumentation. No patient who received surgery through the subvastus approach had a lag of more than 20 degrees, at 48 hours postoperatively, regardless of the instrumentation used. CONCLUSION: Computer-assisted TKA through a medial parapatellar approach was associated with delayed recovery of the quadriceps during early postoperative rehabilitation. This was due to the additional quadriceps dissection required to place the femoral tracking array. The subvastus approach is therefore recommended for computer-assisted TKA.

Potential role of Thermus thermophilus and T. oshimai in high rates of nitrous oxide (N2O) production in ∼80 °C hot springs in the US Great Basin.

Ambient nitrous oxide (N(2)O) emissions from Great Boiling Spring (GBS) in the US Great Basin depended on temperature, with the highest flux, 67.8 ± 2.6 µmol N(2)O-N m(-2) day(-1) , occurring in the large source pool at 82 °C. This rate of N(2)O production contrasted with negligible production from nearby soils and was similar to rates from soils and sediments impacted with agricultural fertilizers. To investigate the source of N(2)O, a variety of approaches were used to enrich and isolate heterotrophic micro-organisms, and isolates were screened for nitrate reduction ability. Nitrate-respiring isolates were identified by 16S rRNA gene sequencing as Thermus thermophilus (31 isolates) and T. oshimai (three isolates). All isolates reduced nitrate to N(2)O but not to dinitrogen and were unable to grow with N(2)O as a terminal electron acceptor. Representative T. thermophilus and T. oshimai strains contained genes with 96-98% and 93% DNA identity, respectively, to the nitrate reductase catalytic subunit gene (narG) of T. thermophilus HB8. These data implicate T. thermophilus and T. oshimai in high flux of N(2)O in GBS and raise questions about the genetic basis of the incomplete denitrification pathway in these organisms and on the fate of biogenic N(2)O in geothermal environments.

Microbiology and geochemistry of Little Hot Creek, a hot spring environment in the Long Valley Caldera.

A culture-independent community census was combined with chemical and thermodynamic analyses of three springs located within the Long Valley Caldera, Little Hot Creek (LHC) 1, 3, and 4. All three springs were approximately 80 degrees C, circumneutral, apparently anaerobic and had similar water chemistries. 16S rRNA gene libraries constructed from DNA isolated from spring sediment revealed moderately diverse but highly novel microbial communities. Over half of the phylotypes could not be grouped into known taxonomic classes. Bacterial libraries from LHC1 and LHC3 were predominantly species within the phyla Aquificae and Thermodesulfobacteria, while those from LHC4 were dominated by candidate phyla, including OP1 and OP9. Archaeal libraries from LHC3 contained large numbers of Archaeoglobales and Desulfurococcales, while LHC1 and LHC4 were dominated by Crenarchaeota unaffiliated with known orders. The heterogeneity in microbial populations could not easily be attributed to measurable differences in water chemistry, but may be determined by availability of trace amounts of oxygen to the spring sediments. Thermodynamic modeling predicted the most favorable reactions to be sulfur and nitrate respirations, yielding 40-70 kJ mol(-1) e(-) transferred; however, levels of oxygen at or below our detection limit could result in aerobic respirations yielding up to 100 kJ mol(-1) e(-) transferred. Important electron donors are predicted to be H(2), H(2)S, S(0), Fe(2+) and CH(4), all of which yield similar energies when coupled to a given electron acceptor. The results indicate that springs associated with the Long Valley Caldera contain microbial populations that show some similarities both to springs in Yellowstone and springs in the Great Basin.

Crenarchaeota colonize terrestrial plant roots.

Microorganisms that colonize plant roots are recruited from, and in turn contribute substantially to, the vast and virtually uncharacterized phylogenetic diversity of soil microbiota. The diverse, but poorly understood, microorganisms that colonize plant roots mediate mineral transformations and nutrient cycles that are central to biosphere functioning. Here, we report the results of epifluorescence microscopy and culture-independent recovery of small subunit (SSU) ribosomal RNA (rRNA) gene sequences showing that members of a previously reported clade of soil Crenarchaeota colonize both young and senescent plant roots at an unexpectedly high frequency, and are particularly abundant on the latter. Our results indicate that non-thermophilic members of the Archaea inhabit an important terrestrial niche on earth and direct attention to the need for studies that will determine their possible roles in mediating root biology.

Perforation of the sigmoid colon by an orthopedic nail: report of a case.

Clinical features and radiographs are presented of a patient whose sigmoid colon was perforated by an orthopedic nail entering the peritoneal cavity via the left acetabulum. The patient was successfully treated by extraction of the nail and closure of the colonic defect.

Influence of tomato genotype on growth of inoculated and indigenous bacteria in the spermosphere.

We previously demonstrated a genetic basis in tomato for support of the growth of a biological control agent, Bacillus cereus UW85, in the spermosphere after seed inoculation (K. P. Smith, J. Handelsman, and R. M. Goodman, Proc. Natl. Acad. Sci. USA 96:4786-4790, 1999). Here we report results of studies examining the host effect on the support of growth of Bacillus and Pseudomonas strains, both inoculated on seeds and recruited from soil, using selected inbred tomato lines from the recombinant inbred line (RIL) population used in our previous study. Two tomato lines, one previously found to support high and the other low growth of B. cereus UW85 in the spermosphere, had similar effects on growth of each of a diverse, worldwide collection of 24 B. cereus strains that were inoculated on seeds and planted in sterilized vermiculite. In contrast, among RILs that differed for support of B. cereus UW85 growth in the spermosphere, we found no difference for support of growth of the biocontrol strains Pseudomonas fluorescens 2-79 or Pseudomonas aureofaciens AB254. Thus, while the host effect on growth extended to all strains of B. cereus examined, it was not exerted on other bacterial species tested. When seeds were inoculated with a marked mutant of B. cereus UW85 and planted in soil, RIL-dependent high and low support of bacterial growth was observed that was similar to results from experiments conducted in sterilized vermiculite. When uninoculated seeds from two of these RILs were planted in soil, changes in population levels of indigenous Bacillus and fluorescent Pseudomonas bacteria differed, as measured over time by culturing and direct microscopy, from growth patterns observed in the inoculation experiments. Neither RIL supported detectable levels of growth of indigenous Bacillus soil bacteria, while the line that supported growth of inoculated B. cereus UW85 supported higher growth of indigenous fluorescent pseudomonads and total bacteria. The vermiculite system used in these experiments was predictive for growth of B. cereus UW85 inoculated on seeds and grown in soil, but the patterns of growth of inoculated strains-both Bacillus and Pseudomonas spp.-did not reflect host genotype effects on indigenous microflora recruited from soil to the spermosphere.

Complete genome sequence of the genetically tractable hydrogenotrophic methanogen Methanococcus maripaludis.

The genome sequence of the genetically tractable, mesophilic, hydrogenotrophic methanogen Methanococcus maripaludis contains 1,722 protein-coding genes in a single circular chromosome of 1,661,137 bp. Of the protein-coding genes (open reading frames [ORFs]), 44% were assigned a function, 48% were conserved but had unknown or uncertain functions, and 7.5% (129 ORFs) were unique to M. maripaludis. Of the unique ORFs, 27 were confirmed to encode proteins by the mass spectrometric identification of unique peptides. Genes for most known functions and pathways were identified. For example, a full complement of hydrogenases and methanogenesis enzymes was identified, including eight selenocysteine-containing proteins, with each being paralogous to a cysteine-containing counterpart. At least 59 proteins were predicted to contain iron-sulfur centers, including ferredoxins, polyferredoxins, and subunits of enzymes with various redox functions. Unusual features included the absence of a Cdc6 homolog, implying a variation in replication initiation, and the presence of a bacterial-like RNase HI as well as an RNase HII typical of the Archaea. The presence of alanine dehydrogenase and alanine racemase, which are uniquely present among the Archaea, explained the ability of the organism to use L- and D-alanine as nitrogen sources. Features that contrasted with the related organism Methanocaldococcus jannaschii included the absence of inteins, even though close homologs of most intein-containing proteins were encoded. Although two-thirds of the ORFs had their highest Blastp hits in Methanocaldococcus jannaschii, lateral gene transfer or gene loss has apparently resulted in genes, which are often clustered, with top Blastp hits in more distantly related groups.