The current prevalence of asthma, allergic rhinitis, and eczema related symptoms in school-aged children in Costa Rica.

OBJECTIVE: Asthma prevalence in Costa Rica is among the highest worldwide. We aimed to determine the prevalence of asthma among school-age children in the Central Highland Area of Costa Rica. METHODS: Cross-sectional study using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was performed. Parents or guardians of children aged 6-13 years completed written questionnaires. RESULTS: Total of 2817 school-aged children returned these questionnaires (74.1% return rate). The prevalence of asthma, rhinitis, and eczema was 21.9%, 42.6%, and 19.2%, respectively. The co-existence of the 3 diseases was seen in 22.6% of children with asthma. Boys had a slightly higher prevalence of these conditions, and younger children had higher prevalence of asthma and eczema, but lower prevalence of rhinitis than older children. The use of acetaminophen and antibiotics in the first 12 months of life showed a significant association with the prevalence of asthma, rhinitis, and eczema. Wheezing with exercise, dry cough at night, and ever rhinitis was highly associated with asthma symptoms in the last 12 months. In contrast, no association was found between children exposed to smoking at home. Frequent traffic next to the house was reported more frequently by the parents of children with asthma, although no significant association was found. CONCLUSION: The prevalence of asthma showed a significant decrease compared to previous studies. However, there was an unexpected high prevalence of rhinitis. Exposure to acetaminophen and antibiotic during the first year of life was highly associated with asthma symptoms.

Promoting cancer screening among churchgoing Latinas: Fe en Acción/faith in action.

Cancer screening rates among Latinas are generally low, reducing the likelihood of early cancer detection in this population. This article examines the effects of a community intervention (Fe en Acción/Faith in Action) led by community health workers (promotoras) on promoting breast, cervical and colorectal cancer screening among churchgoing Latinas. Sixteen churches were randomly assigned to a cancer screening or a physical activity intervention. We examined cancer knowledge, barriers to screening and self-reported mammography, clinical breast exam, Pap test, fecal occult blood test and sigmoidoscopy or colonoscopy at baseline and 12 months follow-up. Participants were 436 adult Latinas, with 16 promotoras conducting a cancer screening intervention at 8 out of 16 churches. The cancer screening intervention had a significant positive impact on self-reported mammography (OR = 4.64, 95% CI: 2.00-10.75) and breast exams in the last year (OR= 2.82, 95% CI: 1.41-5.57) and corresponding reductions in perceived (87.6%) barriers to breast cancer screening (P < .008). Cervical and colorectal cancer screening did not improve with the intervention. These findings suggest Fe en Acción church-based promotoras had a significant impact on promoting breast cancer screening among Latinas. Colon cancer screening promotion, however, remains a challenge.

Mortality in a cohort of complex patients with chronic illnesses and multimorbidity: a descriptive longitudinal study.

BACKGROUND: Certain advanced chronic conditions (heart failure, chronic lung disease) are associated with high mortality. Nevertheless, most of the time, patients with these conditions are not given the same level of attention or palliative care as those with cancer. The objective of this study was to assess mortality and its association with other variables in a cohort of complex multimorbid patients with heart failure and/or lung disease from two consecutive telemonitoring studies. METHODS: This multicentre longitudinal study was conducted between 2010 and 2015. We included 83 patients (27 without telemonitoring) with heart failure and/or lung disease with > 1 hospital admission in the previous year and great difficulties leaving home or were housebound. The following variables were indicators of their complex clinical condition: old age (mean: 81 years), comorbidity (Charlson Comorbidity Index score ≥ 2: 86.2%), both conditions concurrently (54.2%) and home oxygen therapy (52%). We assessed mortality (rate, cause and place of death) and its association with: age, sex, telemonitoring, functional status (Barthel score), quality of life (EQ-5D visual analogue scale), number of medications, and all-cause and condition-specific (due to conditions prompting inclusion) admissions during the previous year. Uni- and bivariate analysis and logistic regression were performed, considering p < 0.05 significant. RESULTS: A total of 61 patients died within 5 years, representing 31.2%/year (95% CI: 23-40.1%), considering the overall follow-up (sum of individual follow-up days). Of these, 81% of deaths (95% CI: 69.1-89-1%) were due to the condition prompting inclusion, and 83.3% (95% CI: 72-90.7%) died in hospital (median: 8.5 days). Mortality was lower among those under telemonitoring (p = 0.027), and with fewer condition-specific admissions the previous year (p = 0.006); the latter also showed the strongest association in the multivariate analysis (Exp(B) = 6.115). CONCLUSIONS: Complex patients with multimorbidity had a high mortality rate, generally dying due to the condition for which they had been included, and in hospital (83.3%). New approaches for managing such patients should be considered, introducing palliative care as required, and using more comprehensive predictors of mortality (functional status and quality of life), together with those related to the illness itself (previous admissions, progression and symptoms).

First Report of Root Rot of Watermelon Caused by Ceratobasidium sp. in Sonora, Mexico.

Watermelon is one of the major crops grown in Mexico and represents 4% of the total cultivated area with fruits in this country. In 2013, Sonora State was ranked second in the production of watermelon at a national level. Fungal and oomycete diseases are among the main biotic factors affecting watermelon production, particularly those caused by species of the genera Fusarium, Phytophthora, Pythium, and Rhizoctonia. During the spring of 2013, wilting or death symptoms were confirmed in approximately 50% of ungrafted watermelon plants grown in four sampled fields along the coast of Hermosillo and Guaymas Valley in Sonora, Mexico. On both roots and stems of infected plants, localized lesions were found that were 0.2 to 2.0 cm long, reddish brown, and slightly sunken on the stem base. In some cases, the discolorations encompassed nearly 90% of the root system. One-centimeter pieces from the edge of lesions on stems and roots were superficially disinfected with 1% sodium hypochlorite, then rinsed with sterile distilled water, placed onto petri dishes containing potato dextrose agar (PDA), and incubated at 25°C for 3 days. Fungal colonies were white initially, then turned brown, and septate hyphae were 3.7 to 4.3 µm in diameter and branched at right angles with a constriction at the origin of the branch point. These characteristics are typical of the genus Rhizoctonia. Binucleate cells from five isolates were observed using a lactophenol aniline blue solution stain, according to Ceratobasidium morphological descriptions. Mycelia from five isolates grown on PDA was used for DNA extraction. The rDNA-ITS region was amplified using PCR with the universal fungal primers ITS1 and ITS4 (3). The purified products were separately sequenced in both directions using the same primer pair. The sequences obtained were 99% similar to those of Ceratobasidium sp. AG-F and AG-Fa isolates (accessions KC193238.1 on Tagetes erecta, HQ168370.1 on Musa spp., and JX913821.1 on soy-rice-weeds, respectively) from GenBank (2,4). The pathogenicity of the fungus was tested under growth chamber conditions. Sets of seven healthy watermelon seedlings of the Sugar red variety were inoculated with five isolates of Ceratobasidium. Three disks (8 mm in diameter) of mycelia grown on PDA were placed around the roots of each plantlet. The pots were maintained at 27 ± 0.1°C for 14 days with a photoperiod of 12 h. Seven uninoculated seedlings were used as a control. Initial symptoms showing water-soaked lesions developed on all inoculated seedlings within 6 to 7 days, while typical disease symptoms appeared after 10 to 14 days after inoculation. Seedlings without inoculum were free from infection. The fungus was re-isolated from the inoculated seedlings on PDA, and identified as Ceratobasidium sp., confirmed using morphological characteristics. A similar disease has been reported recently in Italy and Arizona (1); however, this report is the first description of a Ceratobasidium sp. causing root rot of watermelon in Sonora, Mexico. Agricultural areas where the study was carried represent 90% of the total area cultivated with watermelon in this state, so it is necessary to evaluate the impact of this pathogen in the crop. References: (1) C. Nischwitz et al. APS joint meeting, 2013. (2) A. Saroj et al. Plant Dis. 97:1251, 2013. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (4) J. Yin et al. Plant Dis. 95:490, 2011.

The utility of serologic tests as biomarkers for Helicobacter pylori-associated precancerous lesions and gastric cancer varies between Latin American countries.

PURPOSE: Currently, studies on serologic diagnosis of Helicobacter pylori-associated gastric cancer (GC) in Latin America are scarce. The aim of the present study was to evaluate the association between H. pylori serology tests in patients with early precancerous lesions or GC, when compared with non-atrophic gastritis in Colombia, Paraguay, and Mexico, three countries in Latin America with a high prevalence of H. pylori infection but contrasting rates of GC mortality. METHODS: Gastric biopsies and blood samples were obtained from patients attending the gastroenterology or oncology services of hospitals in the three participating countries. IgG antibodies against H. pylori whole-cell antigens and CagA were tested in 1,117 sera using an enzyme-linked immunoabsorbent assay. RESULTS: Positive and significant associations were shown for H. pylori seropositivity and preneoplastic lesions in Mexico (OR 2.0; 95 % CI 1.1-3.4) but not in Colombia (OR 1.2; 95 % CI 0.6-2.1) or Paraguay (OR 1.5; 95 % CI 0.6-3.2); no significant associations were shown for GC in any country. CagA seropositivity was associated with preneoplasic lesions in all three countries (ORs = 2.1, 3.0, and 3.1 for Mexico, Colombia, and Paraguay, respectively), and with GC only in Colombia (OR 4.3; 95 % CI 2.1-9.2). CONCLUSIONS: In countries of Latin America, the IgG CagA test might be a useful biomarker for patients with gastric preneoplastic lesions and for those at risk of developing gastric cancer.

Biochemical characterization of ecuadorian wild Solanum lycopersicum Mill. plants produced from non-cryopreserved and cryopreserved seeds.

This paper presents some of the effects of cryopreservation of wild Solanum lycopersicum Mill. seeds on the early stages of germination post liquid nitrogen exposure. Percentage of germination, conversion into plantlets and plant fresh mass were evaluated after cryostorage. Levels of chlorophyll pigments (a, b, total), malondialdehyde, other aldehydes, phenolics (cell wall-linked, free, and total) and proteins were determined. Peroxidase and superoxide dismutase activities were recorded. Liquid nitrogen exposure increased the percentage of seed germination at 5 days but at 7 days, the conversion into plantlets and the plant fresh mass were not statistically different between non-cryopreserved and cryopreserved samples. Several significant effects of cryopreservation were recorded at the biochemical level at 7 days of germination under controlled conditions. Highly significant effects due to liquid nitrogen exposure were observed in leaves: increased levels of peroxidase enzymatic and specific activities and cell wall-linked phenolics. Very remarkable effects were also recorded in roots: decreased contents of chlorophylls and cell wall-linked phenolics.

Clinical standards for the diagnosis and management of asthma in low- and middle-income countries.

BACKGROUND: The aim of these clinical standards is to aid the diagnosis and management of asthma in low-resource settings in low- and middle-income countries (LMICs).METHODS: A panel of 52 experts in the field of asthma in LMICs participated in a two-stage Delphi process to establish and reach a consensus on the clinical standards.RESULTS: Eighteen clinical standards were defined: Standard 1, Every individual with symptoms and signs compatible with asthma should undergo a clinical assessment; Standard 2, In individuals (>6 years) with a clinical assessment supportive of a diagnosis of asthma, a hand-held spirometry measurement should be used to confirm variable expiratory airflow limitation by demonstrating an acute response to a bronchodilator; Standard 3, Pre- and post-bronchodilator spirometry should be performed in individuals (>6 years) to support diagnosis before treatment is commenced if there is diagnostic uncertainty; Standard 4, Individuals with an acute exacerbation of asthma and clinical signs of hypoxaemia or increased work of breathing should be given supplementary oxygen to maintain saturation at 94-98%; Standard 5, Inhaled short-acting beta-2 agonists (SABAs) should be used as an emergency reliever in individuals with asthma via an appropriate spacer device for metered-dose inhalers; Standard 6, Short-course oral corticosteroids should be administered in appropriate doses to individuals having moderate to severe acute asthma exacerbations (minimum 3-5 days); Standard 7, Individuals having a severe asthma exacerbation should receive emergency care, including oxygen therapy, systemic corticosteroids, inhaled bronchodilators (e.g., salbutamol with or without ipratropium bromide) and a single dose of intravenous magnesium sulphate should be considered; Standard 8, All individuals with asthma should receive education about asthma and a personalised action plan; Standard 9, Inhaled medications (excluding dry-powder devices) should be administered via an appropriate spacer device in both adults and children. Children aged 0-3 years will require the spacer to be coupled to a face mask; Standard 10, Children aged <5 years with asthma should receive a SABA as-needed at step 1 and an inhaled corticosteroid (ICS) to cover periods of wheezing due to respiratory viral infections, and SABA as-needed and daily ICS from step 2 upwards; Standard 11, Children aged 6-11 years with asthma should receive an ICS taken whenever an inhaled SABA is used; Standard 12, All adolescents aged 12-18 years and adults with asthma should receive a combination inhaler (ICS and rapid onset of action long-acting beta-agonist [LABA] such as budesonide-formoterol), where available, to be used either as-needed (for mild asthma) or as both maintenance and reliever therapy, for moderate to severe asthma; Standard 13, Inhaled SABA alone for the management of patients aged >12 years is not recommended as it is associated with increased risk of morbidity and mortality. It should only be used where there is no access to ICS.The following standards (14-18) are for settings where there is no access to inhaled medicines. Standard 14, Patients without access to corticosteroids should be provided with a single short course of emergency oral prednisolone; Standard 15, Oral SABA for symptomatic relief should be used only if no inhaled SABA is available. Adjust to the individual's lowest beneficial dose to minimise adverse effects; Standard 16, Oral leukotriene receptor antagonists (LTRA) can be used as a preventive medication and is preferable to the use of long-term oral systemic corticosteroids; Standard 17, In exceptional circumstances, when there is a high risk of mortality from exacerbations, low-dose oral prednisolone daily or on alternate days may be considered on a case-by-case basis; Standard 18. Oral theophylline should be restricted for use in situations where it is the only bronchodilator treatment option available.CONCLUSION: These first consensus-based clinical standards for asthma management in LMICs are intended to help clinicians provide the most effective care for people in resource-limited settings.

Non-steroidal anti-inflammatory drugs, acetaminophen, and risk of skin cancer in the Nurses' Health Study.

PURPOSE: Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with lower risk of certain cancers, but data on the effect on skin cancer risk have been limited and contradictory. We prospectively examined whether use of NSAIDS or acetaminophen was associated with a lower risk of skin cancer in women. METHODS: The 92,125 Caucasian women in the Nurses' Health Study provided information on aspirin use in 1980. Other NSAIDs and acetaminophen were added in 1990. Medication use, frequency, and quantity were reassessed on biennial questionnaires. Through 2008, we confirmed 658 melanoma cases, 1,337 squamous cell carcinoma (SCC) cases, and had 15,079 self-reports of basal cell carcinoma (BCC). We used COX proportional hazards models to compute relative risks (RR) adjusted for known skin cancer risk factors. RESULTS: Neither aspirin nor non-aspirin NSAID use was associated with a lower risk of melanoma, SCC, or BCC, even for women with high quantity, frequency, or duration of use. Instead, we observed an increased risk of melanoma among current aspirin users (RR = 1.32, 95 % CI 1.03-1.70), though an increase of similar magnitude among past users and lack of a dose-response effect did not support a pharmacologic mechanism. We observed a mild reduction in SCC risk in current acetaminophen users (RR = 0.88, 95 % CI 0.75-1.02), with a linear decrease in risk with greater frequency of use (p = 0.04). CONCLUSIONS: Aspirin and other NSAIDs were not associated with a lower risk of melanoma, SCC, or BCC in women. Our large, prospective study does not support a chemoprotective effect of NSAIDs against skin cancers.

Simple and sensitive spectrophotometric method for estimating the nitrogen-fixing capacity of bacterial cultures.

Biological nitrogen fixation (BNF) is a process through which a group of microorganisms called diazotrophs convert unassimilable atmospheric nitrogen into ammonia. In aqueous media, ammonia yields ammonium ions that can be assimilated by microorganisms and plants. To reduce the application of nitrogen fertilizers and their environmental effects, an alternative approach toward sustainable agriculture is the induction of artificial associations between diazotrophs and plants. This has led to increased interest in the search for microorganisms capable of supplying nitrogen to crops. This article presents a simple, economical, and sensitive spectrophotometric method for estimating the BNF capacity of bacteria cultured in a liquid NFb medium, based on the variation of absorbance caused by the change in color of bromothymol blue in the culture medium. The structure and color of this indicator are modified by pH shifts, which depend on the concentration of fixed ammonium ions.•The nitrogen concentration (estimated from the ammonium in the culture medium) showed a positive correlation (R 2 = 0.984) with the absorbance measured at 610 nm. The regression equation obtained through the origin was y = 0.009682140x, where y is the absorbance and x is the nitrogen concentration in the culture medium.•The methods used at present to measure the efficiency of BNF require expensive equipment, which may not be affordable for many laboratories or companies working in this field.•This technique can be used for pure bacterial strains and microbial consortia from soil or commercial products.

Body mass index in early adulthood and colorectal cancer risk for carriers and non-carriers of germline mutations in DNA mismatch repair genes.

BACKGROUND: Carriers of germline mutations in DNA mismatch repair (MMR) genes have a high risk of colorectal cancer (CRC), but the modifiers of this risk are not well established. We estimated an association between body mass index (BMI) in early adulthood and subsequent risk of CRC for carriers and, as a comparison, estimated the association for non-carriers. METHODS: A weighted Cox regression was used to analyse height and weight at 20 years reported by 1324 carriers of MMR gene mutations (500 MLH1, 648 MSH2, 117 MSH6 and 59 PMS2) and 1219 non-carriers from the Colon Cancer Family Registry. RESULTS: During 122,304 person-years of observation, we observed diagnoses of CRC for 659 carriers (50%) and 36 non-carriers (3%). For carriers, the risk of CRC increased by 30% for each 5 kg m(-2) increment in BMI in early adulthood (hazard ratio, HR: 1.30; 95% confidence interval, CI: 1.08-1.58; P=0.01), and increased by 64% for non-carriers (HR: 1.64; 95% CI: 1.02-2.64; P=0.04) after adjusting for sex, country, cigarette smoking and alcohol drinking (and the MMR gene that was mutated in carriers). The difference in HRs for carriers and non-carriers was not statistically significant (P=0.50). For MLH1 and PMS2 (MutLα heterodimer) mutation carriers combined, the corresponding increase was 36% (HR: 1.36; 95% CI: 1.05-1.76; P=0.02). For MSH2 and MSH6 (MutSα heterodimer) mutation carriers combined, the HR was 1.26 (95% CI: 0.96-1.65; P=0.09). There was no significant difference between the HRs for MutLα and MutSα heterodimer carriers (P=0.56). CONCLUSION: Body mass index in early adulthood is positively associated with risk of CRC for MMR gene mutation carriers and non-carriers.

Common mental disorders and psychological distress in systemic lupus erythematosus are not associated with disease activity.

Psychiatric diagnosis in patients with systemic lupus erythematosus (SLE) is controversial: variations have been reported in frequency, diagnostic assays, associations with disease activity, autoantibodies, and contributing social factors. Eighty-three consecutive non-selected Chilean patients with SLE were evaluated for: (i) 26 common mental disorders according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), using the Mini-International Neuropsychiatric Interview (MINI-plus); (ii) psychological suffering measured by Hospital Anxiety and Depression Scale (HADS); (iii) ACR 1999 neuropsychiatric (NP)SLE criteria; (iv) SLE disease activity (SLEDAI-2K); (v) cumulative damage (SLICC/ACR); and (vi) anti-ribosomal P antibodies by enzyme-linked immunoassay and immunoblot. Psychiatric diagnoses occurred in 44.6% of patients; the most frequent (21.7%) was major depressive episode (MDE). No association with lupus activity was observed in patients with a DSM-IV diagnosis or MDE or psychological suffering. ACR 1999 NPSLE criteria were present in 42.2% of patients, the majority corresponding to mood (28.9%) or anxiety disorders (15.6%). Suicidal risk was present in 9.6% of patients. Anti-ribosomal P antibodies (13.3%) were not associated with DSM-IV diagnosis. Severe psychiatric disorders in SLE are common and not associated with disease activity.

Mortality and critical conditions in COVID-19 patients at private hospitals: weekend effect?

OBJECTIVE: The aim of the study was to find factors associated with the mortality of admission to the intensive care unit (ICU) in patients with COVID-19. MATERIALS AND METHODS: Retrospective observational study with a database of 1987 patients with COVID-19 who had attended the emergency department of a private hospital network between February 2020 and April 2020 were analyzed. Clinical variables and some laboratory parameters were studied. The Charlson and Elixhauser comorbidity indices were calculated. The dependent variables were mortality and admission to the ICU. A descriptive and correlational analysis was performed. Logistic regression models and Kaplan-Meier survival curves were established. RESULTS: Positive correlations were observed between age, creatinine, and D-dimer levels, as well as with the scores obtained with the Charlson and Elixhauser indices. Differences in the levels of these parameters were also observed when analyzing variables such as mortality, sex or admission to the ICU. Mortality was associated with high creatinine and D-dimer levels and advanced age. Survival curves indicated longer survival in patients not admitted to the ICU, admitted to the hospital during the week, and in those with lower creatinine and D-dimer levels. CONCLUSIONS: Mortality in Spanish patients with COVID-19 admitted to private hospitals was associated with high creatinine and D-dimer levels and advanced age. Longer survival was obtained on weekdays. This study provides valuable information on the management and nursing care of these patients in order to optimize resources in pandemic situations.

Body fluid volume and nutritional status in hemodialysis: vector bioelectric impedance analysis.

BACKGROUND: Protein-energy malnutrition and hypervolemia are major causes of morbidity and mortality in patients on chronic hemodialysis (CHD). The methods used to evaluate nutritional status and volume status remain controversial. Vector bioelectric impedance analysis (vector- BIA) has recently been developed to assess both nutritional status and tissue hydration. The purpose of the study was to assess the nutritional status and volume status of patients on CHD with conventional nutritional assessment methods and with vector-BIA and then to compare the resulting findings. METHODS: 76 Mexican patients on CHD were studied. Nutritional status and body composition were assessed with anthropometry, biochemical variables, and the modified Bilbrey nutritional index (mBNI), the results were compared with both conventional BIA and vector-BIA. RESULTS: The BNI was used to determine the number of patients with normal nutritional status (n = 27, 35.5%), and mild (n = 31, 40.8%), moderate (n = 10, 13.2%) and severe malnutrition (n = 8, 10.5%). Patients displayed shorter vectors with smaller phase angles or with an overhydration vectorial pattern before the initiation of their hemodialysis session. There was general improvement to normal hydration status post-dialysis (p < 0.05); however, 28% remained overhydrated as assessed by vector-BIA. The vector-BIA results showed that worse malnutrition status was associated with greater volume overload (p < 0.05). Diabetes mellitus (DM) was associated with shorter vectors with smaller phase angles (a vectorial pattern of overhydration and cachexia) (p < 0.05). Patients with lower serum creatinine presented with shorter vectors and smaller phase angles (vectorial patterns of malnutrition and/or overhydration) (p < 0.05). In women, lower serum albumin (< 3.4 g/dl) correlated with greater overhydration and malnutrition (p < 0.05). CONCLUSIONS: In this population, the vector-BIA showed that 28% of the population remained overhydrated after their hemodialysis session. Diabetics and those with moderate or severe malnutrition were more overhydrated, which is a condition that may be associated with increased cardiovascular morbidity. Because nutritional and volume status are important factors associated with morbidity and mortality in CHD patients, we focused on optimizing the use of existing methods. Our studies suggest that vector-BIA offers a comprehensive and reliable reproducible means of assessing both volume and masses at the bedside and can complement the traditional methods.

Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. I. Digestibility, fermentation parameters, and microbial growth.

Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of forage to concentrate (F:C) ratio and type of forage in the diet on ruminal fermentation and microbial protein synthesis. The purpose of the study was to assess how closely fermenters can mimic the dietary differences found in vivo. The 4 experimental diets contained F:C ratios of 70:30 or 30:70 with either alfalfa hay or grass hay as the forage. Microbial growth was determined in both systems using (15)N as a microbial marker. Rusitec fermenters detected differences between diets similar to those observed in sheep by changing F:C ratio on pH; neutral detergent fiber digestibility; total volatile fatty acid concentrations; molar proportions of acetate, propionate, butyrate, isovalerate, and caproate; and amylase activity. In contrast, Rusitec fermenters did not reproduce the dietary differences found in sheep for NH(3)-N and lactate concentrations, dry matter (DM) digestibility, proportions of isobutyrate and valerate, carboxymethylcellulase and xylanase activities, and microbial growth and its efficiency. Regarding the effect of the type of forage in the diet, Rusitec fermenters detected differences between diets similar to those found in sheep for most determined parameters, with the exception of pH, DM digestibility, butyrate proportion, and carboxymethylcellulase activity. Minimum pH and maximal volatile fatty acid concentrations were reached at 2h and at 6 to 8h postfeeding in sheep and fermenters, respectively, indicating that feed fermentation was slower in fermenters compared with that in sheep. There were differences between systems in the magnitude of most determined parameters. In general, fermenters showed lower lactate concentrations, neutral detergent fiber digestibility, acetate:propionate ratios, and enzymatic activities. On the contrary, fermenters showed greater NH(3)-N concentrations, DM digestibility, and proportions of propionate, butyrate, isovalerate, valerate, and caproate. Values of efficiency of microbial growth were greater in fermenters compared with sheep for 70:30 diets, but they were lower for 30:70 diets. Differences between fermentation in sheep and fermenters can be mainly attributed to the lack of absorption in fermenters, differences in solid retention time, and compartmentalization in the Rusitec system. In general, the Rusitec system simulated more closely the in vivo fermentation of high-forage diets compared with high-concentrate diets.

Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. II. Protozoa population and diversity of bacterial communities.

Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of dietary characteristics on microbial populations and bacterial diversity. The purpose of the study was to assess how closely fermenters can mimic the differences between diets found in vivo. The 4 experimental diets contained forage to concentrate (F:C) ratios of 70:30 (high forage; HF) or 30:70 (high concentrate; HC) with either alfalfa hay (A) or grass hay (G) as the forage. Total bacterial numbers were greater in the rumen of sheep fed HF diets compared with those fed HC diets, whereas the opposite was found in fermenters. The numbers of cellulolytic bacteria were not affected by F:C ratio in any fermentation system, but cellulolytic numbers were 2.7 and 1.8 times greater in sheep than in fermenters for HF and HC diets, respectively. Neither total bacterial nor cellulolytic numbers were affected by the type of forage in sheep or fermenters. Decreasing F:C ratio increased total protozoa and Entodiniae numbers in sheep by about 29 and 25%, respectively, but it had no effect in fermenters. Isotrichidae and Ophryoscolecinae numbers in sheep were not affected by changing F:C ratio, but both disappeared completely from fermenters fed HC diets. Total protozoa and Entodiniae numbers were greater in sheep fed A diets than in those fed G diets, whereas the opposite was found in fermenters. Results indicate that under the conditions of the present study, protozoa population in Rusitec fermenters was not representative of that in the rumen of sheep fed the same diets. In addition, protozoa numbers in fermenters were 121 and 226 times lower than those in the sheep rumen for HF and HC diets, respectively. The automated ribosomal intergenic spacer analysis of the 16S ribosomal DNA was used to analyze the diversity of liquid- and solid-associated bacteria in both systems. A total of 170 peaks were detected in the automated ribosomal intergenic spacer analysis electropherograms of bacterial pellets across the full set of 64 samples, from which 160 were detected in at least 1 individual from each system (sheep or fermenter). Diversity of liquid-associated bacterial pellets was greater with G diets in fermenters but seemed to be unaffected by diet in sheep. Bacterial diversity in solid-associated bacteria pellets was greater for G diets compared with A diets in sheep and fermenters. Different conditions in the fermenters compared with sheep rumen might have caused a selection of some bacterial strains.

Fluctuations in measured radioactive decay rates inside a modified Faraday cage: Correlations with space weather.

For several years, reports have been published about fluctuations in measured radioactive decay time-series and in some instances linked to astrophysical as well as classical environmental influences. Anomalous behaviors of radioactive decay measurement and measurement of capacitance inside and outside a modified Faraday cage were documented by our group in previous work. In the present report, we present an in-depth analysis of our measurement with regard to possible correlations with space weather, i.e. the geomagnetic activity (GMA) and cosmic-ray activity (CRA). Our analysis revealed that the decay and capacitance time-series are statistically significantly correlated with GMA and CRA when specific conditions are met. The conditions are explained in detail and an outlook is given on how to further investigate this important finding. Our discovery is relevant for all researchers investigating radioactive decay measurements since they point out that the space weather condition during the measurement is relevant for partially explaining the observed variability.

Effects of dilution rate and retention time of concentrate on efficiency of microbial growth, methane production, and ruminal fermentation in Rusitec fermenters.

The objective of this study was to investigate the effects of 2 dilution rates (DL) and 2 concentrate retention times (RT) on microbial growth, methane production, and fermentation of a 30:70 alfalfa hay:concentrate diet in Rusitec fermenters maintained at similar pH. The DL were 3.78 (low DL, LDL) and 5.42%/h (high DL, HDL), and concentrate RT was either 24 h (T24) or 48 h (T48). Forage RT was 48 h in all fermenters. Apparent disappearance of diet DM and NDF was greater in HDL fermenters compared with LDL fermenters, but there was a significant DL x concentrate RT interaction, showing that the effect of DL was more pronounced in T48 compared with T24 fermenters. Methane production was not affected by DL, but was greater in T48 compared with T24 fermenters, which was consistent with the increased fiber degradation in T48 fermenters. Increasing DL augmented volatile fatty acid production and molar proportions of propionate, isovalerate, and valerate, and reduced those of caproate, but no effects were observed on acetate, butyrate, and isobutyrate proportions. Increasing concentrate RT resulted in greater volatile fatty acid production and proportions of acetate, butyrate, and caproate, but reduced those of propionate, valerate, and isovalerate. Ammonia-N production was not affected by concentrate RT, but was greater at HDL compared with LDL. Microbial growth was not affected by DL, but microbial growth efficiency was lower in HDL compared with LDL fermenters. Concentrate RT affected microbial growth and its efficiency, with both being greater in T48 compared with T24 fermenters. Carboxymetylcellulase and xylanase activities in ruminal fluid were greater in HDL compared with LDL fermenters, but were not affected by concentrate RT. There were DL x concentrate RT interactions for diet apparent disappearance, molar proportions of propionate, butyrate, isovalerate, and caproate, and acetate:propionate ratio, indicating that effects of DL on these variables were influenced by concentrate RT. The results would indicate that using higher DL and shorter concentrate RT than those typically used in Rusitec fermenters would contribute to improving the simulation of in vivo fermentation of high-concentrate diets.

Influence of detachment procedure and diet on recovery of solid-associated bacteria from sheep ruminal digesta and representativeness of bacterial isolates as assessed by automated ribosomal intergenic spacer analysis-polymerase chain reaction.

Six ruminally and duodenally cannulated sheep were used in a partially replicated 4 x 4 Latin square experiment designed to evaluate the efficiency of 3 detachment procedures (DP) to recover solid-associated bacteria (SAB) from ruminal digesta. The 4 experimental diets contained forage to concentrate (F:C) ratios of 70:30 or 30:70 with either alfalfa hay or grass hay as the forage. Bacterial biomass was labeled with 15NH4Cl. The DP were 1) MET: digesta was incubated at 38 degrees C for 15 min with saline solution (0.9% NaCl) containing 0.1% methylcellulose under continuous shaking; 2) STO: digesta was mixed with cold saline solution and homogenized with a stomacher for 5 min at 230 rpm; 3) FRE: digesta was immediately frozen at -20 degrees C for 72 h, thawed at 4 degrees C, mixed with saline solution and subjected to STO procedure. Common to all treatments was storing at 4 degrees C for 24 h after the treatment, homogenization, filtration, and resuspension of digesta 2 times in the treatment solutions. The automated ribosomal intergenic spacer analysis of the 16S ribosomal DNA was used to analyze the similarity between bacterial communities attached to the digesta and those in the pellet obtained after each DP. There were no significant F:C x DP or forage x DP interactions for any variable. On average, STO treatment detached 65.8% of SAB from ruminal digesta, about 1.2 and 1.5 times more than FRE and MET treatments, respectively. Total recovery of SAB in STO pellets (48.9%) was greater compared with FRE (31.7%) and MET (33.1%), values being greater for high-forage compared with high-concentrate diets. Similarity index between the bacteria attached to digesta and those in the pellets were lower for FRE (48.2%) compared with MET (54.1%) and STO (54.1%), which suggests that FRE could have destroyed cell integrity of some bacterial species, thus reducing the bacterial diversity present in the pellets. The STO method was the most effective removing SAB from digesta, but only a moderate similarity between the bacterial communities attached to digesta and those recovered in the bacterial pellets was obtained. Values of duodenal microbial flow estimated using SAB as reference bacteria were greater with FRE compared with STO and MET, but all DP detected similar differences between diets, and therefore did not influence the interpretation of results.

A simple silica-based method for metagenomic DNA extraction from soil and sediments.

A new method is described for extraction of metagenomic DNA from soil and sediments which is based on DNA adsorption to silica without the use of phenol, ethanol precipitation or a cesium chloride gradient. High-quality DNA was obtained, and PCR inhibition was overcome by adding bovine serum albumin and adjusting magnesium concentration. By using PCR-DGGE with Firmicutes and lactic acid bacteria-specific primers the extracted metagenomic DNA was shown to contain a mixture of bacterial genomes. This method can be used for screening bacterial diversity in soil and sediment samples.

In vitro evaluation of germination and growth of five plant species on medium supplemented with hydrocarbons associated with contaminated soils.

The effect of a hydrocarbon mixture (HCM) of three polycyclic aromatic hydrocarbons (PAH) and Maya crude oil on germination, growth and survival of four grasses (Bouteloua curtipendula, Cenchrus ciliaris, Echinochloa crusgalli and Rhynchelytrum repens) was studied and compared to a control (Festuca arundinacea) under in vitro conditions. The species were cultured on MS medium with different HCM initial concentrations. Germination was not affected for any assayed concentration; however, the length of the stems and roots decreased when HCM increased and the survival of the four species also diminished. Except for F. arundinacea, a direct link between hydrocarbon concentration and plant survival was observed. In vitro studies are clean and easy to handle techniques allowing isolation of the plant activity from that derived from associations with microorganisms in non-sterile cultures. To our knowledge, this is the first work towards phytoremediation assisted by in vitro plant cultivation.