A combined microbial and biogeochemical dataset from high-latitude ecosystems with respect to methane cycle

High latitudes are experiencing intense ecosystem changes with climate warming. The underlying methane (CH₄) cycling dynamics remain unresolved, despite its crucial climatic feedback. Atmospheric CH₄ emissions are heterogeneous, resulting from local geochemical drivers, global climatic factors, and microbial production/consumption balance. Holistic studies are mandatory to capture CH₄ cycling complexity. Here, we report a large set of integrated microbial and biogeochemical data from 387 samples, using a concerted sampling strategy and experimental protocols. The study followed international standards to ensure inter-comparisons of data amongst three high-latitude regions: Alaska, Siberia, and Patagonia. The dataset encompasses different representative environmental features (e.g. lake, wetland, tundra, forest soil) of these high-latitude sites and their respective heterogeneity (e.g. characteristic microtopographic patterns). The data included physicochemical parameters, greenhouse gas concentrations and emissions, organic matter characterization, trace elements and nutrients, isotopes, microbial quantification and composition. This dataset addresses the need for a robust physicochemical framework to conduct and contextualize future research on the interactions between climate change, biogeochemical cycles and microbial communities at high-latitudes.

Measurement(s)	microbial diversity • microbial abundances • cations and anions • trace elements
Technology Type(s)	MiSeq sequencing 16S rRNA gene • Real Time PCR • HPLC • ICP-MS
Sample Characteristic - Organism	bacteria • archaea
Sample Characteristic - Environment	lake water • lake sediment • wetland • peatland • soil • pond
Sample Characteristic - Location	Western Siberia • Alaska • Patagonia • Cape Horn province • Magellanic subantarctic ecoregion

Virus-to-prokaryote ratio in the Salar de Huasco and different ecosystems of the Southern hemisphere and its relationship with physicochemical and biological parameters

The virus-to-prokaryote ratio (VPR) has been used in many ecosystems to study the relationship between viruses and their hosts. While high VPR values indicate a high rate of prokaryotes' cell lysis, low values are interpreted as a decrease in or absence of viral activity. Salar de Huasco is a high-altitude wetland characterized by a rich microbial diversity associated with aquatic sites like springs, ponds, streams and a lagoon with variable physicochemical conditions. Samples from two ponds, Poza Rosada (PR) and Poza Verde (PV), were analyzed by epifluorescence microscopy to determine variability of viral and prokaryotic abundance and to calculate the VPR in a dry season. In addition, to put Salar de Huasco results into perspective, a compilation of research articles on viral and prokaryotic abundance, VPR, and metadata from various Southern hemisphere ecosystems was revised. The ecosystems were grouped into six categories: high-altitude wetlands, Pacific, Atlantic, Indian, and Southern Oceans and Antarctic lakes. Salar de Huasco ponds recorded similar VPR values (an average of 7.4 and 1.7 at PR and PV, respectively), ranging from 3.22 to 15.99 in PR. The VPR variability was associated with VA and chlorophyll a, when considering all data available for this ecosystem. In general, high-altitude wetlands recorded the highest VPR average (53.22 ± 95.09), followed by the Oceans, Southern (21.91 ± 25.72), Atlantic (19.57 ± 15.77) and Indian (13.43 ± 16.12), then Antarctic lakes (11.37 ± 15.82) and the Pacific Ocean (6.34 ± 3.79). Physicochemical variables, i.e., temperature, conductivity, nutrients (nitrate, ammonium, and phosphate) and chlorophyll a as a biological variable, were found to drive the VPR in the ecosystems analyzed. Thus, the viral activity in the Wetland followed similar trends of previous reports based on larger sets of metadata analyses. In total, this study highlights the importance of including viruses as a biological variable to study microbial temporal dynamics in wetlands considering their crucial role in the carbon budgets of these understudied ecosystems in the southern hemisphere.

[The thin ALT perforator flap for oropharyngeal robotic-assisted reconstruction]

Since a few years, the transoral robotic surgery reduced the morbidity of oropharyngeal tumors excision. Large posterior tumors can now be removed without any scar visible on the face. In this context and to respect the thinness required for reconstructions at the junction of the upper aerodigestive tract, the free radial forearm flap still remains the solution of choice. However, if the transoral robotic surgery respects the anatomy and the aesthetics of patients at the visible and social area that represents the face, the forearm flap provides visible scars on the other region of social interaction that represents the upper limb. The aim of our work was to prove the feasibility and the benefits in terms of reducing sequelae when using a thin anterolateral perforator flap harvested above the plane of the superficial fascia. We present this new original method in detail and the advantages it offers to patients after surgery.

Paclitaxel plus carboplatin (PC) in patients with metastatic melanoma (MM): Experience in a single institution

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Background: The number of agents active in patients with metastatic melanoma is limited and cure is not an objective for treatment at this stage, so that clinical benefit in these patients is the most important. The aim of the study was to evaluate the efficacy and safety of combination regimen consisting of paclitaxel and carboplatin as second-line chemotherapy, in patients with MM. Based on reports of responses to PC, 17 patients with MM was treated at the National Cancer Institute of Mexico. Methods: We evaluated retrospectively the combination of PC in patients with MM. Data regarding patient characteristics and outcomes were abstracted from medical records of NCI of Mexico from 01/05 to 12/08. The regimen was weekly paclitaxel (at a dose of 80 mg/m2) received on days 1, 8, and 15 of a 21-day cycle and carboplatin (AUC 5) on day 1. Response evaluation was using RECIST and toxicity was according to National Cancer Institute Common Toxicity Criteria. This study was approved by the hospital ethics committee. Results: Seventeen patients with MM were treated with PC. All patients were previously treated (and failed) with dacarbazine (DTIC). Sixteen were assessable for response with three cycles of chemotherapy and seventeen for toxicity. One patient was deemed to be ineligible because they presented severe hypersensitivity reaction to paclitaxel at beginning. Objective partial response were obtained in 4 patients (25%); 8 stable disease (50%) at least four months. No patient had a complete response to therapy. Progression disease was in 4 patients (25%). In 12 (75%) we noted clinical benefit. The median time to disease progression for the entire group was 4.2 months (range, 1–11 mos), with a median overall survival of 8.1 months (range, 5.6–10.5 mos). The toxicity grade 3 reported was thrombocytopenic in 2 patients (11%) and anemia in one patient (6%). Additional patients had reversible toxicities grade 3 including alopecia, nausea and fatigue; 2 of them presented moderate hypersensitivity reactions to paclitaxel. No toxic death was noted. Conclusions: The PC combination appears to be safety and well tolerated in second line chemotherapy in MM, however we need more patients to demonstrate a true clinical benefit, we outcomes are according with other clinical reports.

No significant financial relationships to disclose.

Heightened bronchial hyperresponsiveness in the absence of heightened atopy in children with current wheezing and low income status

BACKGROUND

Although global studies such as the International Study of Asthma and Allergies in Childhood (ISAAC) have provided valuable data on the prevalence of asthma in children in Latin America, there is little information on the relationship between asthma symptoms, pulmonary function, bronchial hyperresponsiveness (BHR) and atopy in the region.

METHODS

This study examined the relationship between self-reported wheezing in the past 12 months, pulmonary function, airway responsiveness and atopy in children from a low income population in a neighbourhood of Santiago, Chile. Two random samples (100 each) of children aged 13-14 years who participated in ISAAC phase I were selected according to whether or not they reported wheezing in the past 12 months. Spirometry, the methacholine bronchial challenge test and the prick test were performed in all individuals.

RESULTS

Children who reported current wheezing had significantly higher BHR to methacholine compared with those without wheezing (71.6% vs 52.6%; p = 0.007) and no significant difference was found in forced expiratory volume in 1 s (116.7 (12.3)% vs 120.3 (14.5%); p = 0.11). The prevalence of atopy was not significantly different between those children who reported wheezing compared with those who did not (44.2% vs 42.3%; p = 0.89). Multiple regression analysis showed that only BHR to methacholine (OR 2.72, 95% CI 1.25 to 4.13; p = 0.01) and maternal asthma (OR 3.1, 95% CI 1.2 to 8.3, p = 0.03) were significant risk factors for current wheezing.

CONCLUSIONS

Our results support previous findings suggesting that in adolescents from underprivileged populations, self-reported current wheezing is related to BHR but not to atopy.

Disinfection of sludge with high pathogenic content using silver and other compounds

A physicochemical sludge with high microbial content (10(2)-10(4) FPU/g TS bacteriophages, 10(6)-10(7) MPN/g TS faecal coliforms, 10(4) MPN/g TS Salmonella spp., 10(4) MPN/g TS Shigella spp., 10(3) MPN/g TS Pseudomonas aeruginosa, 10(2) MPN/g TS Vibrio cholerae, 10(2)-10(3) cysts/g TS Giardia sp., 10(2)-10(4) oocyts/g TS Cryptosporidium sp., 168-215 viable helminth ova/g TS) was disinfected using silver, silver-copper, and silver-copper plus a synergistic agent (SA). Twenty milligrams Ag/g TS inactivated 4.8 log of faecal coliforms in 1 h; however, 40 mg Ag/g TS are needed to reduce helminth ova viability from 84 to 38.4% in the same period of time. Combinations of Ag-Cu (60:600 mg Ag-Cu/g TS) and Ag-SA (60:24 mg Ag-SA/g TS) inactivated 7.8 log of faecal coliforms and around 90% of helminth ova in 60 min. To produce USEPA class A biosolids, 10:100:8 and 5:50:13.3 mg Ag-Cu-SA/gTS are needed. Bacterial regrowth was not observed for all conditions producing <1000 MPN/gTS faecal coliforms, suggesting a residual disinfection effect. Recommended doses to produce class A biosolids inactivated 2-4 log of bacteriophages, 4 log of Salmonella spp., 4 log of Shigella spp., 3 log of Pseudomonas aeruginosa, 2 log of Vibrio cholerae, 87-99.9% of Giardia sp., and 75-99.9% of Cryptosporidium sp.

Most humoral non-responders to hepatitis B vaccines develop HBV-specific cellular immune responses

About 10% of health care professionals vaccinated against hepatitis B virus (HBV) fail to develop protective antibodies. We tested the capacity of peripheral blood lymphocytes from 121 health care professionals, including 76 non-responders, to proliferate to four HBV vaccines, examined the proliferating cells' subset, production of IFN-gamma, IL-4 and IL-10, and for 22 subjects, the cytokine production genotype. Specific proliferative responses to at least one HBV antigen were noted in 75% humoral non-responders. These cells differed from the CD4+ strongly proliferating cells of responders. Non-responders frequently displayed a genotype of high TGF-beta and intermediate IL-10 secretion. Most humoral non-responders to HBV thus develop specific cellular immune responses, eventually liable to protect them against viral infection.

[Idiopathic membranous nephropathy associated with anti-calcineurin toxicity. Prognosis and other immunosuppressive treatments]

A 32-year-old male patient was admitted at our department presenting microhematuria and full nephrotic syndrome in April 1995. A percutaneous kidney biopsy showed a stage I-lI membranous nephropathy and an eight-week course with oral prednisone was initiated without response. Then, oral cyclosporine A (3.5 mg/kg/day) was given and after 5 weeks of treatment, remission of the nephrotic syndrome was observed but creatinine raised to 1.6 mg/dl, normalizing after reducing the dose of cyclosporine A. We discuss the settings, prognostic and therapeutic alternatives for idiopathic membranous nephropathy.

Glutamate activates PP125(FAK) through AMPA/kainate receptors in Bergmann glia

Glial glutamate receptors are likely to play a role in plasticity, learning, and memory and in a number of neuropathologies. An enhanced glutamate-dependent tyrosine phosphorylation has been detected in such processes. Using primary cultures of chick Bergmann glia cells and chick cerebellar slices, we addressed whether glial glutamate receptors can activate the nonreceptor tyrosine kinase pp125 focal adhesion kinase (pp125(FAK)). A dose- and time-dependent tyrosine phosphorylation of pp125(FAK) was found in both preparations upon glutamate treatment. This effect was mediated through alpha-amino-3-hydroxy-5-methyl-4-isoaxazolepropionate (AMPA)/kainate (KA) receptors, as shown by its inhibition by the specific antagonists 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7- sulfonamide (NBQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX) and the lack of effect of metabotropic agonists. FAK tyrosine phosphorylation was dependent on phosphatidylinositol 3-kinase activity. As expected, an increase in pp125(FAK) catalytic activity was found upon glutamate treatment. Immunprecipitation experiments demonstrated that FAK associates with ionotropic glutamate receptors. Taken together, these results suggest a role for glial glutamate receptors in cytoskeletal rearrengments and focal adhesion contact formation and provide new insight into the signaling transactions elicited by this neurotransmitter in glial cells.

Development of reverse transcription-PCR assays specific for detection of equine encephalitis viruses

Specific and sensitive reverse transcription-PCR (RT-PCR) assays were developed for the detection of eastern, western, and Venezuelan equine encephalitis viruses (EEE, WEE, and VEE, respectively). Tests for specificity included all known alphavirus species. The EEE-specific RT-PCR amplified a 464-bp region of the E2 gene exclusively from 10 different EEE strains from South and North America with a sensitivity of about 3,000 RNA molecules. In a subsequent nested PCR, the specificity was confirmed by the amplification of a 262-bp fragment, increasing the sensitivity of this assay to approximately 30 RNA molecules. The RT-PCR for WEE amplified a fragment of 354 bp from as few as 2,000 RNA molecules. Babanki virus, as well as Mucambo and Pixuna viruses (VEE subtypes IIIA and IV), were also amplified. However, the latter viruses showed slightly smaller fragments of about 290 and 310 bp, respectively. A subsequent seminested PCR amplified a 195-bp fragment only from the 10 tested strains of WEE from North and South America, rendering this assay virus specific and increasing its sensitivity to approximately 20 RNA molecules. Because the 12 VEE subtypes showed too much divergence in their 26S RNA nucleotide sequences to detect all of them by the use of nondegenerate primers, this assay was confined to the medically important and closely related VEE subtypes IAB, IC, ID, IE, and II. The RT-PCR-seminested PCR combination specifically amplified 342- and 194-bp fragments of the region covering the 6K gene in VEE. The sensitivity was 20 RNA molecules for subtype IAB virus and 70 RNA molecules for subtype IE virus. In addition to the subtypes mentioned above, three of the enzootic VEE (subtypes IIIB, IIIC, and IV) showed the specific amplicon in the seminested PCR. The practicability of the latter assay was tested with human sera gathered as part of the febrile illness surveillance in the Amazon River Basin of Peru near the city of Iquitos. All of the nine tested VEE-positive sera showed the expected 194-bp amplicon of the VEE-specific RT-PCR-seminested PCR.

A membrane form of brain L-glutamate decarboxylase: identification, isolation, and its relation to insulin-dependent mellitus

A membrane form of L-glutamate decarboxylase (GAD) was identified and purified to apparent homogeneity from hog brain. The purified GAD was established as an integral membrane protein by phase-partitioning assay, charge-shift electrophoresis, and chromatography on a hydrophobic interaction column. This membrane GAD has a native molecular mass of 96 +/- 5 kDa and is a homodimer of 48 +/- 3-kDa subunits. Immunoprecipitation and immunoblotting tests revealed the presence of antibodies against this membrane GAD in sera from patients with insulin-dependent diabetes mellitus. Since this form of GAD appears to be an integral membrane protein and is presumed to have extracellular domains exposed, it seems reasonable to suggest that membrane GAD is more likely than soluble GAD to be involved in the pathogenesis of insulin-dependent diabetes and related autoimmune disorders such as stiff-man syndrome.

Is sodium necessary for stimulus-secretion coupling in toad (Caudiverbera caudiverbera) adrenal chromaffin cells?

1. Chromaffin cells of the toad were used to investigate the effects of total replacement of extracellular Na+ by monovalent cations or sucrose on secretion of catecholamine (CA). 2. K+, Rb+ or Cs+ in place of Na+ produced an immediate secretory response, which are dependent on extracellular Ca2+ and it was blocked by Co2+. Li+ or choline+ did not affect basal secretion. 3. Isosmotic replacement of Na+ by sucrose caused CA secretion even in the absence of external Ca2+ or in the presence of Ca-channel blockers. 4. Tetraethylammonium decreased the extent of CA release produced by either K+ or Rb+. 5. The secretagogue effect of Na+/K+, Na+/Rb+ or Na+/Cs+ replacement could be explained by a depolarization of the cell membrane, which ultimately will cause Ca2+ influx through voltage-dependent Ca-channels. However, the present results indicate that Na+ may be sufficient but not necessary for CA secretion.

[Must acute carotid thrombosis be surgically treated? 1962-1973: long-term results]

A study of long-term results (mean follow-up: 10.6 years) in 22 patients operated on for acute carotid thrombosis between 1962 and 1973 is reported. In most instances, surgery was performed at the acute phase of a massive cerebrovascular occlusion, usually more than 8 hours after onset (10 cases). Five of these patients (22%) died in the postoperative period. Eight (35%) recovered without residual disease. In six, the condition improved, while it remained unchanged or worsened in three (14%). There were ten delayed deaths, including two from a recurrent cerebrovascular episode and four from cardiac disease. The actuarial survival curve does not differ from that of patients treated conservatively, with rates being 60% at five years, 36% at ten years and 28% at thirteen years. The quality of certain postoperative results suggests that surgical indications at the acute stage of carotid occlusion be reviewed. The study of thirty series from the literature (1 046 cases) shows a 17% mortality rate, while 50% of patients recover or improve. This mortality is significantly lower in recent statistics, under 10%: this improvement may be ascribable to more rigid surgical indications (delay under 6 hours, operation in variable neurologic deficiencies, early diagnosis by the Doppler procedure, better postoperative management). The authors conclude that surgical management of acute carotid thrombosis should no longer be systematically dismissed.