Effects of Volcanic Pumice Inputs on Microbial Community Composition and Dissolved C/P Ratios in Lake Waters: an Experimental Approach.

Volcanic eruptions discharge massive amounts of ash and pumice that decrease light penetration in lakes and lead to concomitant increases in phosphorus (P) concentrations and shifts in soluble C/P ratios. The consequences of these sudden changes for bacteria community composition, metabolism, and enzymatic activity remain unclear, especially for the dynamic period immediately after pumice deposition. Thus, the main aim of our study was to determine how ambient bacterial communities respond to pumice inputs in lakes that differ in dissolved organic carbon (DOC) and P concentrations and to what extent these responses are moderated by substrate C/P stoichiometry. We performed an outdoor experiment with natural lake water from two lakes that differed in dissolved organic carbon (DOC) concentration. We measured nutrient concentrations, alkaline phosphatase activity (APA), and DOC consumption rates and assessed different components of bacterial community structure using next-generation sequencing of the 16S rRNA gene. Pumice inputs caused a decrease in the C/P ratio of dissolved resources, a decrease in APA, and an increase in DOC consumption, indicating reduced P limitation. These changes in bacteria metabolism were coupled with modifications in the assemblage composition and an increase in diversity, with increases in bacterial taxa associated with biofilm and sediments, in predatory bacteria, and in bacteria with gliding motility. Our results confirm that volcanic eruptions have the potential to alter nutrient partitioning and light penetration in receiving waterways which can have dramatic impacts on microbial community dynamics.

Interaction between lithification and resource availability in the microbialites of Río Mesquites, Cuatro Ciénegas, México.

Lithified microbial structures (microbialites) have been present on Earth for billions of years. Lithification may impose unique constraints on microbes. For instance, when CaCO3 forms, phosphate may be captured via coprecipitation and/or adsorption and potentially rendered unavailable for biological uptake. Therefore, the growth of microbes associated with CaCO3 may be phosphorus-limited. In this study, we compared the effects of resource addition on biogeochemical functions of microbial communities associated with microbialites and photoautotrophic microbial communities not associated with CaCO3 deposition in Río Mesquites, Cuatro Ciénegas, México. We also manipulated rates of CaCO3 deposition in microbialites to determine whether lithification reduces the bioavailability of phosphorus (P). We found that P additions significantly increased rates of gross primary production (F2,13 = 103.9, P < 0.001), net primary production (F2,13 = 129.6, P < 0.0001) and ecosystem respiration (F2,13 = 6.44, P < 0.05) in the microbialites, while P addition had no effect on photoautotrophic production in the non-CaCO3 -associated microbial communities. Growth of the non-CaCO3-associated phototrophs was only marginally stimulated when nitrogen and P were added simultaneously (F1,36 = 3.98, P = 0.053). In the microbialites, resource additions led to some shifts in the abundance of Proteobacteria, Bacteroidetes and Cyanobacteria but mostly had little effect on bacterial community composition. Ca(2+) uptake rates increased significantly with organic carbon additions (F1,13 = 8.02, P < 0.05). Lowering of CaCO3 deposition by decreasing calcium concentrations in the water led to increased microbial biomass accumulation rates in terms of both organic carbon (F4,48 = 5.23, P < 0.01) and P (F6,48 = 13.91, P < 0.001). These results provide strong evidence in support of a role of lithification in controlling P limitation of microbialite communities.

A randomized, double-blind, placebo-controlled study of the effects of pomegranate extract on rising PSA levels in men following primary therapy for prostate cancer.

BACKGROUND: The primary objective of this study was to compare the effects of pomegranate juice on PSA doubling times (PSADT) in subjects with rising PSA levels after primary therapy for prostate cancer. METHODS: Double-blind, placebo-controlled multi-institutional study, evaluated the effects of pomegranate liquid extract on serum PSA levels. The primary end point of this study was change in serum PSADT. Additional secondary and exploratory objectives were to evaluate the safety of pomegranate juice and to determine the interaction of manganese superoxide dismutase (MnSOD) AA genotype and pomegranate treatment on PSADT. RESULTS: One-hundred eighty-three eligible subjects were randomly assigned to the active and placebo groups with a ratio of 2:1 (extract N=102; placebo N=64; juice N=17). The majority of adverse events were of moderate or mild grade. Median PSADT increased from 11.1 months at baseline to 15.6 months in the placebo group (P<0.001) compared with an increase from 12.9 months at baseline to 14.5 months in the extract group (P=0.13) and an increase from 12.7 at baseline to 20.3 in the juice group (P=0.004). However, none of these changes were statistically significant between the three groups (P>0.05). Placebo AA patients experienced a 1.8 month change in median PSADT from 10.9 months at baseline to 12.7 months (P=0.22), while extract patients experienced a 12 month change in median PSADT from 13.6 at baseline to 25.6 months (P=0.03). CONCLUSIONS: Compared with placebo, pomegranate extract did not significantly prolong PSADT in prostate cancer patients with rising PSA after primary therapy. A significant prolongation in PSADT was observed in both the treatment and placebo arms. Men with the MnSOD AA genotype may represent a group that is more sensitive to the antiproliferative effects of pomegranate on PSADT; however, this finding requires prospective hypothesis testing and validation.

Community structure and biogeochemical impacts of microbial life on floating pumice.

Volcanic eruptions are a widespread force of geological and ecological disturbance and present recurrent opportunities for the study of biological responses to novel habitat formation. However, scientific study of such events is difficult given their short duration and often distant location. Here we report results from opportunistic sampling of unique volcano-generated habitats formed during the 2011 explosive eruption in the Puyehue-Cordón Caulle complex (Chile), when massive amounts of pumice were ejected, creating novel floating substrata that have never before been characterized from a microbiological perspective. DNA sequencing revealed a dynamic community of microbes that came to inhabit the pumice, with a unique composition distinct from that of the lakes' surface waters and with suggestions of ecological convergence across lakes and sampling times. Furthermore, biogeochemical studies of net nutrient fluxes showed that, while the fresh pumice arriving to the lakes was an initial source of phosphorus (P), colonized pumice had high rates of nitrogen (N) and P uptake and was sufficiently abundant to represent a significant lake-wide nutrient sink. These findings highlight the remarkable versatility of microbes in exploiting novel environments and are consistent with a recent proposal of floating pumice as a favorable environment for the initial origins of life on early Earth.

Rate of delivery of hyperbaric oxygen treatments does not affect response in soft tissue radionecrosis.

BACKGROUND: Soft tissue radiation necrosis (STRN) is effectively treated with hyperbaric oxygen (HBO,), believed to result from stimulation ofangiogenesis in radiation-injured tissue. Thirty to forty HBO2 treatments are usually recommended for STRN. For various reasons, different hyperbaric facilities offer these treatments once or twice daily and from 5-7 days weekly. It is not known whether the clinical response differs as a result of the rate of administration of HBO2 treatments. METHODS: Details of hyperbaric treatment courses of patients treated for radiation enteritis/proctitis (n = 65) and cystitis (n = 94) at a single institution were reviewed. Outcomes were compared with the total number of HBO2 treatments administered and also rate of treatment administration. RESULTS: Responses were similar for both forms of STRN whether the patient averaged fewer or greater than 5 treatments per week, or even < or = 3 versus > or = 7 treatments weekly. Outcome did differ, however, dependant on the total number of treatments administered. Response was better in patients receiving 30 or more total treatments, as compared with fewer. CONCLUSIONS: Soft tissue radionecrosis of the gastrointestinal tract or bladder is (1) effectively treated with hyperbaric oxygen, (2) has a higher response rate if at least 30 treatments are administered, and (3) is equally responsive to rates of hyperbaric treatment ranging from 3 or fewer to 7 or more treatments per week.

Adenocarcinoma of the testicular adnexa presenting with metastatic disease.

Primary epididymal adenocarcinoma is a rare malignancy with fewer than 30 documented cases. We report a case of a 57-year-old patient with a paratesticular mass in the presence of retroperitoneal metastatic disease. Histology confirmed the presence of primary paratesticular adenocarcinoma. In this report we review the index case, the pertinent literature and discuss adjuvant therapy.

Comparison of complications after radical and partial nephrectomy: results from the National Veterans Administration Surgical Quality Improvement Program.

OBJECTIVE: To determine whether radical nephrectomy causes less morbidity, less mortality and is associated with a shorter hospital stay than is partial nephrectomy. PATIENTS AND METHODS: A total of 1885 nephrectomies (1373 radical and 512 partial) conducted between 1991 and 1998 in the Department of Veterans Affairs (VA) National Surgical Quality Improvement Program were evaluated. Using multivariate analyses, outcomes were risk-adjusted based on 45 preoperative variables to compare mortality and morbidity rates. RESULTS: The unadjusted 30-day mortality was 2.0% for radical and 1.6% for partial nephrectomy (P = 0.58). Risk-adjusting the two groups did not result in a statistically significant difference in mortality. The 30-day overall morbidity rate was 15% for radical and 16.2% for partial nephrectomy (P = 0.52); risk-adjusted morbidity rates were not statistically different. There were no statistically significant differences in the rates of postoperative progressive renal failure, acute renal failure, urinary tract infection, prolonged ileus, transfusion requirement, deep wound infection, or extended length of stay. CONCLUSIONS: Partial nephrectomy carried out in the VA program has low morbidity and mortality rates, comparable with the complication rates after radical nephrectomy.

Prostate brachytherapy in patients with median lobe hyperplasia.

Our aim was to document the technical and clinical course of prostate brachytherapy patients with radiographic evidence of median lobe hyperplasia (MLH). Eight patients with MLH were identified during our routine brachytherapy practice, representing 9% of the 87 brachytherapy patients treated during a 6-month period. No effort was made to avoid brachytherapy in patients noted to have MLH on diagnostic work-up. Cystoscopic evaluation was not routinely performed. Postimplant axial computed tomographic (CT) images of the prostate were obtained at 0.5 cm intervals. Preimplant urinary obstructive symptoms were quantified by the criteria of the American Urologic Association (AUA). Each patient was contacted during the writing of this report to update postimplant morbidity information. There was no apparent association between the degree of MLH and preimplant prostate volume or AUA score. Intraoperatively, we were able to visualize MLH by transrectal ultrasound and did not notice any particular difficulty placing sources in the MLH tissue or migration of sources out of the tissue. The prescription isodose covered from 81% to 99% of the postimplant CT-defined target volume, achieving adequate dose to the median lobe tissue in all patients. Two of the eight patients developed acute, postimplant urinary retention. The first patient required intermittent self-catheterization for 3 months and then resumed spontaneous urination. MLH does not appear to be a strong contraindication to prostate brachytherapy, and prophylactic resection of hypertrophic tissue in such patients is probably not warranted. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 152-156 (2000).

Cystourethroscopic findings before and after prostate brachytherapy.

PURPOSE: To assess the role of cystourethroscopy in predicting the risk of postimplant urinary retention. MATERIALS AND METHODS: Fifteen unselected prostate brachytherapy patients implanted with 125I or 103Pd under spinal or general anesthesia were studied. Following induction of anesthesia, the patient was placed in the lithotomy position and cystourethroscopy performed using a 17 sheath and a 30 degrees lens. Irrigation pressure was 100-cm water. A photograph was taken from the level of the verumontanum. At completion of the implant procedure, a second cystourethroscopy was performed and another photograph taken. The degree of obstruction was rated using a 3-point scale. Each patient was contacted at the time of this report to update postimplant morbidity information with follow-up from 1 to 10 months. RESULTS: The patients' preimplant cystourethroscopic findings ranged from minimal to complete occlusion. There was no clear relationship between the American Urologic Association (AUA) score or preimplant prostate volume and the degree of obstruction. Nearly all patients had some increased physical obstruction following completion of the procedure, but only 8 of 14 patients had an increase in obstruction grade. Six patients were completely obstructed at the completion of the implant procedure, only one of whom developed urinary retention. CONCLUSIONS: Marked variability in cystourethroscopy findings do not appear to have a strong influence on the likelihood of postimplant urinary retention and are not a reliable predictor of retention.

Steady-state kinetic analysis of human ubiquitin-activating enzyme (E1) using a fluorescently labeled ubiquitin substrate.

We report the synthesis of fluorescently labeled ubiquitin (Ub) and its use for following ubiquitin transfer to various proteins. Using Oregon green (Og) succinimidyl ester, we prepared a population of Ub mainly labeled by a single Og molecule; greater than 95% of the Og label is associated with Lys 6 of Ub. We demonstrate that Og-Ub is efficiently accepted by Ub-utilizing enzymes, such as the human ubiquitin-activating enzyme (E1). We used this fluorescent substrate to follow the steady-state kinetics of human E1-catalyzed Ub-transfer to the ubiquitin-carrier enzyme Ubc4. In this reaction, E1 uses three substrates: ATP, Ubc4, and Ub. The steady-state kinetics of Og-Ub utilization by E1 is presented. We have also used analytical ultracentrifugation methods to establish that E1 is monomeric under our assay condition (low salt) as well as under physiological condition (150 mM NaCl).

[Hypertrichosis and gingival hypertrophy regression in renal transplants following the substitution of cyclosporin by tacrolimus]. / Régression de l'hypertrichose et de l'hypertrophie gingivale chez des greffés rénaux suite à la substitution de la cyclosporine par le tacrolimus.

Gingival Hyperplasia (GH) and hypertrichosis (HT) are two sides effects associated with the usage of cyclosporine (CyA) but not with tacrolimus (FK 506). The aim of this study is to evaluate the efficacy and security of the conversion from CsA to FK 506 to treat those two complications. From August 1996 to May 1997, 15 patients (9 males, 6 females) aged from 23 to 63 years old (38 +/- 14, mean +/- SD) were switched from CsA to FK 506, 12 for GH, 2 for HT and one for combined presentation. FK 506 was first initiated at a dose of 0.15 mg/kg/day and then adjusted to a level target of 8 ng/ml. The conversion was done on an out patient basis at average 35 (5-83) months after transplantation. Patients were followed prospectively for 12 months. There was a significant reduction in GH in all patients within 3 months. Five out 13 patients had a complete resolution of GH within three months of conversion, 9/12 within 6 months and all by 12 months. HT resolved completely within 6 months. No rejection episode occurred and the serum creatinin remain stable over one year post conversion. Conversion from CsA to FK 506 is thus a safe and valid option to treat CsA induced GH and HT.

Fournier's gangrene in a modern surgical setting: improved survival with aggressive management.

OBJECTIVE: To examine the outcome of 23 consecutive patients with Fournier's gangrene. PATIENTS AND METHODS: Patients' charts were reviewed retrospectively from all those treated for Fournier's gangrene between July 1994 and July 1997 at the UCLA affiliated hospitals. RESULTS: Twenty-three patients were identified (mean age 51.7 years, range 13-71). The aetiologies included perirectal abscess (43%), urethral stricture (30%), scrotal abscess (21%) and unknown (4%). Predisposing factors included diabetes mellitus (43%), steroids or chemotherapy (21%), alcohol abuse (43%), malignancy (26%) and radiation therapy (9%). All 23 patients initially received wide debridement and placement of a percutaneous suprapubic tube. At the time of the first surgery, total scrotectomy was required in all, colostomy in 17% and penectomy in 4%. An additional 35% required eventual colostomy and an additional 9% required a penectomy. Patients underwent repeat debridement a mean of 2.5 times; the overall survival was 96%. CONCLUSION: Survival can be improved in patients with Fournier's gangrene by combining aggressive surgical and medical management. The keys to successful outcome included a high index of suspicion, prompt fluid resuscitation, rapid initiation of broad-spectrum antibiotics, a multidisciplinary approach, early surgical intervention with radical debridement, haemodynamic support in an intensive care setting, and frequent repeat operative debridement.

Recognition of prostate-specific antigenic peptide determinants by human CD4 and CD8 T cells.

It is now becoming accepted that one is not tolerant to all the determinants of self proteins: the T cell repertoire directed to some sequences in self proteins is intact and can be activated. When a self protein is exclusively expressed by tumour cells, the T cell repertoire directed to the particular self antigen can potentially be activated to attack the tumour: this would amount to induction of a beneficial autoimmune response. Prostate cancer offers a unique opportunity for activation of a tumour-specific immune response owing to the exclusive synthesis of prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSM) by prostatic tissue and prostate tumour cells. In this study we examine the CD4 and CD8 T cell repertoires specific for peptides of PSA and PSM in normal human male individuals, using short-term, peptide antigen-driven CD4 and CD8 T cell lines. We show that short-term, CD4 T cell lines derived from six HLA-DR4 individuals showed strong proliferative responses to six of 10 tested peptides of PSA, selected as to contain a DR4 binding motif. Short-term, CD8 T cell lines from three HLA-A1 individuals showed specific cytolytic activity for autologous targets loaded with five of five tested peptides of PSA and PSM, selected to possess an HLA-A1 binding motif. One of the peptides chosen is termed a 'dual-motif' peptide, as it encodes determinants for both CD4 and CD8 T cells. These results, indicating the existence of CD4 and CD8 T cells against determinants of the self proteins, PSA and PSM, in healthy male individuals reveal the potential of the T cell repertoire from the typical prostate cancer patient to eradicate prostate tumours upon being appropriately activated.

Apoptosis mediated by HIV protease is preceded by cleavage of Bcl-2.

Expression of the human immunodeficiency virus type 1 (HIV) protease in cultured cells leads to apoptosis, preceded by cleavage of bcl-2, a key negative regulator of cell death. In contrast, a high level of bcl-2 protects cells in vitro and in vivo from the viral protease and prevents cell death following HIV infection of human lymphocytes, while reducing the yields of viral structural proteins, infectivity, and tumor necrosis factor alpha. We present a model for HIV replication in which the viral protease depletes the infected cells of bcl-2, leading to oxidative stress-dependent activation of NF kappa B, a cellular factor required for HIV transcription, and ultimately to cell death. Purified bcl-2 is cleaved by HIV protease between phenylalanine 112 and alanine 113. The results suggest a new option for HIV gene therapy; bcl-2 muteins that have noncleavable alterations surrounding the HIV protease cleavage site.

Production and purification of human fibroblast collagenase (MMP-1) expressed in the methylotrophic yeast Pichia pastoris.

The cDNA that encodes the proenzyme form of human fibroblast collagenase (proMMP-1) was expressed in the methylotrophic yeast Pichia pastoris. The proMMP-1 encoding DNA was fused to the Saccharomyces cerevisiae pre-pro alpha-mating factor secretion signal in the P. pastoris pPIC9 expression plasmid, transformed into strain GS115 (His-), and His+ Muts (slow methanol utilization) transformants were selected. Full-length proenzyme and processed forms of the protein could be detected in yeast culture supernatants following shake flask and 10-liter fermentations. The protein was purified to greater than 95% homogeneity. The recombinant proMMP-1 was comparable to the native fibroblast material based on (i) migration of the full-length molecule as a 52-kDa protein on reducing SDS-PAGE, (ii) correct N-terminal amino acid sequence, (iii) activation of the full-length molecule by 4-amino-phenylmercuric acetate to yield processed protein species, (iv) degradation of gelatin as monitored by zymogram gels, and (v) enzymatic activity. These data suggest that the P. pastoris expression system offers a convenient and efficient means to produce and purify MMP-1.

Ureteropelvic junction repair: stent and vent.

PURPOSE: We report on a simple technique of how to stent and vent the anastomosis after ureteropelvic junction repair in children. MATERIALS AND METHODS: An 8F feeding tube housing a 4F ureteral catheter, each trimmed to different lengths, was used to stent a ureteropelvic junction anastomosis in a 3-year-old girl with 1 functional kidney. On postoperative day 7 the ureteral catheter was removed and a nephrostogram was performed via the remaining feeding tube, which could also function as a nephrostomy tube. RESULTS: The combined tubes were simply constructed, easily cared for during the postoperative period, served the purpose of stenting and could provide nephrostomy drainage if necessary. CONCLUSIONS: We recommend our stent and vent system in select cases of ureteropelvic junction repair.

[Acute tubular necrosis in patients after kidney transplantation: associated factors and impact on functional survival of the graft]. / Nécrose tubulaire aiguë chez les transplantés rénaux: facteurs associés et impact sur la survie fonctionnelle de la greffe.

Acute tubular necrosis (ATN) represents a serious problem in kidney transplantation. We have reviewed the causes and effects of ATN on kidney transplant patients treated in our hospital between June 1981 and December 1992. We analyzed 359 consecutive kidney transplants performed in 338 patients (213 male and 125 female). There were 311 first grafts. The actuarial functional graft survival (AFGS) was 85% at 1 year and 58.2% at 10 years. The incidence of long-term chronic rejection, the 1-year creatinine blood level (CBL) and the AFGS are summarized: [table: see text] The donor age and the PRA level were significantly correlated with ATN occurrence. ATN after transplantation was associated with a poorer function and survival of the kidney graft. Better donor and patient selection could decrease the occurrence of ATN, thus improving the graft outcome.