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1.
Int J Impot Res ; 2022 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-35941221

RESUMEN

Sickle cell disease (SCD) is an inherited hemoglobin disorder characterized by the occlusion of small blood vessels by sickle-shaped red blood cells. SCD is associated with a number of complications, including ischemic priapism. While SCD accounts for at least one-third of all priapism cases, no definitive treatment strategy has been established to specifically treat patients with SC priapism. The aim of this systematic review was to assess the efficacy and safety of contemporary treatment modalities for acute and stuttering ischemic priapism associated with SCD. The primary outcome measures were defined as resolution of acute priapism (detumescence) and complete response of stuttering priapism, while the primary harm outcome was as sexual dysfunction. The protocol for the review has been registered (PROSPERO Nr: CRD42020182001), and a systematic search of Medline, Embase, and Cochrane controlled trials databases was performed. Three trials with 41 observational studies met the criteria for inclusion in this review. None of the trials assessed detumescence, as a primary outcome. All of the trials reported a complete response of stuttering priapism; however, the certainty of the evidence was low. It is clear that assessing the effectiveness of specific interventions for priapism in SCD, well-designed, adequately-powered, multicenter trials are strongly required.

2.
Sci Rep ; 11(1): 180, 2021 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-33420179

RESUMEN

Nearly a fourth of all enzymatic activities is attributable to oxidoreductases, and the redox reactions supported by this vast catalytic repertoire sustain cellular metabolism. In many biological processes, reduction depends on hydride transfer from either reduced nicotinamide adenine dinucleotide (NADH) or its phosphorylated derivative (NADPH). Despite longstanding efforts to regenerate NADPH by various methods and harness it to support chemoenzymatic synthesis strategies, the lack of product purity has been a major deterrent. Here, we demonstrate that a nanostructured heterolayer Ni-Cu2O-Cu cathode formed by a photoelectrochemical process has unexpected efficiency in direct electrochemical regeneration of NADPH from NADP+. Remarkably, two-thirds of NADP+ was converted to NADPH with no measurable production of the inactive (NADP)2 dimer and at the lowest reported overpotential [- 0.75 V versus Ag/AgCl (3 M NaCl) reference]. Sputtering of nickel on the copper-oxide electrode nucleated an unexpected surface morphology that was critical for high product selectivity. Our results should motivate design of integrated electrolyzer platforms that deploy this heterogeneous catalyst for direct electrochemical regeneration of NADH/NADPH, which is central to design of next-generation biofuel fermentation strategies, biological solar converters, energy-storage devices, and artificial photosynthesis.

3.
Rev Sci Instrum ; 89(8): 084302, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30184712

RESUMEN

We present a method for designing and optimizing an in-house designed electromagnetic probe for distinguishing morphological differences in biological tissues. The probe comprises concentric multi-wound coils, the inner being the primary coil and the outer being the detector coil. A time-varying voltage is imposed on the primary coil, resulting in an induced current in the detector coil. For highly conductive samples, eddy currents are induced in the sample and inductively couple with the electromagnetic probe. However, in weakly conducting samples, the primary coupling mechanism is found to be capacitive though there can be a non-negligible inductive component. Both the mutual inductive coupling and the capacitive coupling between the sample and the probe are detected as a change in the induced voltage of the detector coil using lock-in detection. The induced voltage in the detector coil is influenced more by the morphological structure of the specimen rather than by changes in electrical conductivity within different regions of the sample. The instrument response of the lock-in amplifier is also examined with simulated input voltage signals to relate its output to specific changes in inductive and capacitive coupling, in order to relate sample characteristics to a single voltage output. A circuit element model is used to interpret the experimental measurements. It is found that the sensitivity of the measurement for a given set of probe characteristics (resistances, inductances, and capacitances) can be optimized by adding a small amount of capacitance in the external circuit in parallel with the detector coil. Illustrative measurements are presented on animal (porcine and bovine) tissue and on human liver tissue containing a metastatic tumor to demonstrate the capabilities of the probe and measurement method in distinguishing different tissue types despite having similar electrical conductivities. Since biological tissues are multi-scale, heterogeneous materials comprising regions of differing conductivity, permittivity, and morphological structure, the electromagnetic method presented here has the potential to examine structural variations in tissue undergoing physical changes due to healing or disease.


Asunto(s)
Técnicas Citológicas/instrumentación , Campos Electromagnéticos , Animales , Bovinos , Diseño de Equipo , Humanos
4.
Andrology ; 6(3): 396-407, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29600542

RESUMEN

Testosterone gel formulations have become a popular testosterone replacement therapy in patients with hypogonadism since their advent in the year 2000. The gel formulations restore testosterone levels to mid-normal physiological levels (14-17.5 nmol/L) as early as within 24 h, and help alleviate the signs and symptoms of testosterone deficiency, thereby leading to an improved quality of life. Although testosterone gels have a favourable efficacy and safety profile as compared to injectable and patch formulations, risk of secondary exposure poses a challenge. Approved testosterone topical formulations include Tostrex® (Tostran® , Fortesta® ), Androgel® (Testogel® ), Testim® and Axiron® (solution), which have a favourable efficacy profile and positively impacted patient-reported outcome(s). Besides, Testavan, which is a 2% testosterone gel, is under registration in Europe and already approved in Australia in May 2017. Testavan uses a novel hydroalcoholic and highly viscous topical formulation. This product comes with a metered dose dispenser and a cap applicator that allows a hands-free application for precise dispensing and application. The present article provides a comprehensive review of pharmacokinetic, tolerability and safety profile of the testosterone gels available in the market along with the new 2% testosterone gel, Testavan.


Asunto(s)
Terapia de Reemplazo de Hormonas/métodos , Testosterona/administración & dosificación , Administración Tópica , Geles , Terapia de Reemplazo de Hormonas/efectos adversos , Humanos , Hipogonadismo/tratamiento farmacológico , Masculino , Testosterona/efectos adversos , Testosterona/farmacocinética
5.
Andrology ; 4(3): 486-91, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-27027684

RESUMEN

There is a clear association between low serum testosterone and coronary artery disease (CAD) in men. Hypotestosteronaemia is associated with accelerated atherosclerosis and a quarter of men with CAD are biochemically hypogonadal. Amongst those with CAD, hypotestosteronaemia is associated with increased mortality. Testosterone vasodilates coronary arteries, and exogenous testosterone reduces ischaemia. Whether hypotestosteronaemia is a cause or a consequence of CAD remains unanswered. The aim of this prospective observational study was to investigate whether coronary revascularization affected androgen status in men with stable angina pectoris. Twenty five men (mean age 62.7, SD 9.18) with angiographically significant CAD and symptomatic angina underwent full coronary revascularization by percutaneous coronary intervention. Androgen status and symptoms of angina, stress, depression and sexual function were assessed before, and at one and 6 months after the coronary revascularization. All patients underwent complete revascularization which was associated with a significant reduction in angina symptoms and ischaemia. No significant difference was seen in total testosterone (11.33 nmol/L baseline; 12.56, 1 month post; 13.04 at 6 months; p = 0.08). A significant and sustained rise in sex hormone-binding globulin was seen (33.99 nm/L baseline; 36.11 nm/L 1 month post PCI; 37.94 nm/L at 6 months; p = 0.03) Overall, there was no significant alteration in any other marker of androgen status including free testosterone or bioavailable testosterone. There was no change in symptoms of anxiety, depression or sexual function. Coronary revascularization has no sustained effect on androgen status. This supports the hypothesis that hypotestosteronaemia is not a consequence of angina pectoris or myocardial ischaemia.


Asunto(s)
Angina Estable/cirugía , Intervención Coronaria Percutánea , Globulina de Unión a Hormona Sexual/metabolismo , Testosterona/sangre , Anciano , Angina Estable/sangre , Depresión/sangre , Depresión/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Estrés Psicológico/sangre , Estrés Psicológico/diagnóstico , Resultado del Tratamiento
6.
Obes Rev ; 16(7): 581-606, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25982085

RESUMEN

Testosterone is a key hormone in the pathology of metabolic diseases such as obesity. Low testosterone levels are associated with increased fat mass (particularly central adiposity) and reduced lean mass in males. These morphological features are linked to metabolic dysfunction, and testosterone deficiency is associated with energy imbalance, impaired glucose control, reduced insulin sensitivity and dyslipidaemia. A bidirectional relationship between testosterone and obesity underpins this association indicated by the hypogonadal-obesity cycle and evidence weight loss can lead to increased testosterone levels. Androgenic effects on enzymatic pathways of fatty acid metabolism, glucose control and energy utilization are apparent and often tissue specific with differential effects noted in different regional fat depots, muscle and liver to potentially explain the mechanisms of testosterone action. Testosterone replacement therapy demonstrates beneficial effects on measures of obesity that are partially explained by both direct metabolic actions on adipose and muscle and also potentially by increasing motivation, vigour and energy allowing obese individuals to engage in more active lifestyles. The degree of these beneficial effects may be dependent on the treatment modality with longer term administration often achieving greater improvements. Testosterone replacement may therefore potentially be an effective adjunctive treatment for weight management in obese men with concomitant hypogonadism.


Asunto(s)
Terapia de Reemplazo de Hormonas , Hipogonadismo/complicaciones , Obesidad/prevención & control , Receptores Androgénicos/uso terapéutico , Testosterona/deficiencia , Tejido Adiposo/efectos de los fármacos , Adulto , Humanos , Hipogonadismo/sangre , Hipogonadismo/tratamiento farmacológico , Masculino , Obesidad/sangre , Obesidad/etiología , Factores de Riesgo , Testosterona/sangre , Testosterona/uso terapéutico
7.
Int J Food Microbiol ; 194: 21-4, 2015 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-25461604

RESUMEN

Due to the lack of an efficient cultivation system, little is known about the stability and inactivation of hepatitis E virus (HEV). In addition, there is a lack of information on which cultivable virus(es) are suitable as model or surrogate viruses for HEV. Murine norovirus (MNV) and F-RNA coliphage MS2 are potential surrogates and F-RNA coliphages are a potential indicator for enteric viruses. However, the numbers of F-RNA coliphages excreted by swine are relatively low. In contrast, Porcine teschovirus (PTV) is cultivable and is excreted abundantly. PTV is readily detected on swine carcasses and the potential of PTV as a viral indicator of fecal contamination on hog carcasses is currently being explored, however, there is no information on the environmental stability of PTV. The survival of PTV was determined on vacuum packaged pork chops during storage at 2°C using cultivation and molecular techniques and compared to published data on the survival of MNV and MS2 under similar conditions. Viable PTV was reduced by ≥1.8log units compared to a reduction of 0.6 log genomic copies after 7weeks. The viability data indicates that PTV is less stable than MS2 and MNV during storage at 2°C whereas similar reductions in genomic copies were observed for all 3 viruses. This study provides data on the survival of PTV on pork and insight on the potential of PTV as a surrogate for HEV in the pork processing chain.


Asunto(s)
Frío , Microbiología de Alimentos , Carne/virología , Teschovirus/fisiología , Animales , Manipulación de Alimentos , Viabilidad Microbiana , Porcinos , Factores de Tiempo
8.
Andrology ; 2(6): 819-34, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25269643

RESUMEN

The objective of this review was to summarize the literature on the risk factors, comorbidities, and consequences of male hypogonadism, which is defined as a syndrome complex that includes biochemical confirmation of low testosterone (T) and the consistent symptoms and signs associated with low T. A systematic literature search was performed in PubMed/MEDLINE, EMBASE, Cochrane Library for articles published in the last 10 years on risk factors, comorbidities, and consequences of male hypogonadism. Of the 53 relevant studies identified, nine examined potential risk factors, 14 examined potential comorbidities, and 30 examined potential consequences of male hypogonadism. Based on studies conducted in Asia, Australia, Europe, and North & South America, the important factors that predicted and correlated with hypogonadism were advanced age, obesity, a diagnosis of metabolic syndrome (MetS), and a poor general health status. Diabetes mellitus was correlated with hypogonadism in most studies, but was not established as a risk factor. Although diseases, such as coronary heart disease, hypertension, stroke, and peripheral arterial disease did not predict hypogonadism, they did correlate with incident low T. The data reviewed on potential consequences suggest that low T levels may be linked to earlier all-cause and cardiovascular related mortality among men. This literature review suggests that men with certain factors, such as advanced age, obesity, MetS, and poor general health, are more likely to have and develop hypogonadism. Low levels of T may have important long-term negative health consequences.


Asunto(s)
Hipogonadismo/epidemiología , Comorbilidad , Humanos , Hipogonadismo/complicaciones , Hipogonadismo/fisiopatología , Masculino , Factores de Riesgo
9.
Food Microbiol ; 42: 225-31, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24929741

RESUMEN

The numbers of coliforms, Escherichia coli, F-RNA coliphages, bovine enteric calicivirus (BEC) and rotavirus (RV) and presence of non-O157 shiga toxigenic E. coli (STEC) were determined on commercial vacuum packaged beef subprimals at the retail level from swabs obtained from the entire surfaces of 150 cuts that originated from federally and provincially registered plants. The prevalence and log mean numbers of E. coli were higher in provincially registered plants than in federally registered plants; 64% vs 20%, respectively, and -0.3 vs -1.22 log cfu/100 cm(2), respectively. In contrast, the prevalence and mean log numbers of F-RNA coliphages were lower for the provincially registered plants than for the federally registered plants; 31% vs 68% and -0.86 vs -0.13 log cfu/100 cm(2), respectively. One E. coli sample tested positive for stx2 and eae. F-RNA coliphages associated with human origin (GII/GIII) were detected in 12% and 30% of samples that originated from provincially and federally registered plants, respectively. RV RNA was detected in 4% of samples while BEC RNA was not detected. Although the infectivity of RV is unknown, the presence of viable F-RNA coliphages suggests that consumers could potentially be at risk when consuming undercooked meat that is contaminated with RV.


Asunto(s)
Bacteriófagos/crecimiento & desarrollo , Escherichia coli/crecimiento & desarrollo , Contaminación de Alimentos/análisis , Productos de la Carne/microbiología , Carne/microbiología , Carne/virología , Norovirus/aislamiento & purificación , Rotavirus/crecimiento & desarrollo , Animales , Bacteriófagos/clasificación , Bacteriófagos/genética , Bacteriófagos/aislamiento & purificación , Bovinos , Seguridad de Productos para el Consumidor , Escherichia coli/clasificación , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Embalaje de Alimentos , Humanos , Productos de la Carne/economía , Norovirus/clasificación , Norovirus/genética , Rotavirus/clasificación , Rotavirus/genética , Rotavirus/aislamiento & purificación
10.
J Virol Methods ; 206: 5-11, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24880068

RESUMEN

Increasing attention is being paid to the impact of agricultural activities on water quality to understand the impact on public health. F-RNA coliphages have been proposed as viral indicators of fecal contamination while porcine teschovirus (PTV) and porcine adenovirus (PAdV) are proposed indicators of fecal contamination of swine origin. Viruses and coliphages are present in water in very low concentrations and must be concentrated to permit their detection. There is little information comparing the effectiveness of the methods for concentrating F-RNA coliphages with concentration methods for other viruses and vice versa. The objective of this study was to compare 5 current published methods for recovering F-RNA coliphages, PTV and PAdV from river water samples concentrated by electronegative nitrocellulose membrane filters (methods A and B) or electropositive Zeta Plus 60S filters (methods C-E). Method A is used routinely for the detection of coliphages (Méndez et al., 2004) and method C (Brassard et al., 2005) is the official method in Health Canada's compendium for the detection of viruses in bottled mineral or spring water. When river water was inoculated with stocks of F-RNA MS2, PAdV, and PTV to final concentrations of 1×10(6) PFU/100 mL, 1×10(5) gc/100 mL and 3×10(5) gc/100 mL, respectively, a significantly higher recovery for each virus was consistently obtained for method A with recoveries of 52% for MS2, 95% for PAdV, and 1.5% for PTV. When method A was compared with method C for the detection of F-coliphages, PAdV and PTV in river water samples, viruses were detected with higher frequencies and at higher mean numbers with method A than with method C. With method A, F-coliphages were detected in 11/12 samples (5-154 PFU/100 mL), PTV in 12/12 samples (397-10,951 gc/100 mL), PAdV in 1/12 samples (15 gc/100 mL), and F-RNA GIII in 1/12 samples (750 gc/100 mL) while F-RNA genotypes I, II, and IV were not detected by qRT-PCR.


Asunto(s)
Adenovirus Porcinos/aislamiento & purificación , Levivirus/aislamiento & purificación , Ríos/virología , Teschovirus/aislamiento & purificación , Contaminación del Agua , Calidad del Agua , Adenovirus Porcinos/genética , Canadá , Filtración/métodos , Levivirus/genética , Sensibilidad y Especificidad , Teschovirus/genética , Acoplamiento Viral
11.
Andrology ; 2(2): 205-211, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24574152

RESUMEN

Erectile dysfunction (ED) and low testosterone levels are common in men with type 2 diabetes (T2D). We have investigated the impact of testosterone on quality of life (QoL) in diabetic men with ED. Men with ED were identified within a study cohort of 355 men with T2D. All subjects completed SF-36 health and Androgen Deficiency of the Aging Male questionnaires. Total tesosterone (TT), bioavailable testosterone (BT) and sex hormone-binding globulin levels of study participants were measured and free testosterone levels were calculated (cFT). A subgroup of 126 ED patients completed the International Index of Erectile Function-5 (IIEF-5) questionnaire. Linear regression analyses were corrected for age, body mass index (BMI), glycosylated haemoglobin (HbA1c), smoking, alcohol consumption and cardiovascular disease (CVD). Total SF-36 scores significantly and positively correlated with TT levels (r = 0.219, p = 0.001), BT levels (r = 0.199, p = 0.004) and cFT levels (r = 0.185, p = 0.007) among men with ED. These trends were strengthened after adjusting for age, BMI, HbA1c, smoking, alcohol consumption and CVD (TT r = 0.359, p = 0.015; BT r = 0.354, p = 0.024 and cFT r = 0.354, p = 0.024). IIEF-5 scores significantly correlated inversely with TT (r = 0.546, p = 0.001), BT (r = 0.506, p = 0.004) and cFT levels (r = 0.532, p = 0.001). A positive linear relationship was observed between IIEF-5 scores and total SF-36 score (r = 0.491, p = 0.003). Patients who reported having ED had an average SF-36 score of 9.1% less than those without ED (p < 0.001). Lower testosterone and greater severity of ED independently correlated with poorer physical function, social function, vitality and decline in general health domains of the SF-36. This is the first study to report that testosterone deficiency and severity of ED are both independently associated with reduced QoL in men with T2D. Furthermore, ED and low testosterone are markers of poor health which impact on an individual's self-perception of their health status.


Asunto(s)
Diabetes Mellitus Tipo 2/sangre , Disfunción Eréctil/sangre , Calidad de Vida , Testosterona/sangre , Testosterona/deficiencia , Factores de Edad , Índice de Masa Corporal , Humanos , Masculino , Persona de Mediana Edad , Globulina de Unión a Hormona Sexual/análisis , Encuestas y Cuestionarios
12.
J Virol Methods ; 198: 26-31, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24384096

RESUMEN

There is an increasing interest in using oral fluid to determine herd health and documenting the circulation of viruses in commercial swine populations but little is known about the stability of viruses in oral fluid. Hepatitis E virus (HEV) is a zoonotic virus which is widespread in swine herds. Information on optimal handling methods such as heat treatments, freezing and RNA stabilization agents is needed to prevent or minimize degradation of viral RNA by degradative enzymes. The objectives of the study were to determine optimum handling conditions of the oral fluid before RNA extraction and to compare the performance of the RNeasy Protect Saliva Mini kit, which contains a stabilizing agent, with that of the QIAamp Viral RNA Mini kit, which does not contain a stabilizing agent. Preliminary studies with oral fluid inoculated with HEV indicated that a heat treatment of 60°C for 15min was detrimental to HEV RNA. HEV was recovered from 25/25 and 24/25 samples of oral fluid when samples were incubated for ≤24h at 4°C and 30days at -20°C, respectively, without a stabilizing agent and extracted with the QiaAMP kit. In contrast, HEV RNA was detected in 16/25 and 11/25 samples when samples were incubated with a stabilizing agent for 24h at 37°C and 30days at -20°C, respectively, and extracted with the RNeasy Protect Saliva kit. Moreover, the mean number of genome copies/ml of HEV recovered from oral fluid stored at -20°C without the stabilizing agent was 2.9 log units higher than oral fluid stored at -20°C in the presence of the stabilizing agent. The recovery of RNA from HEV, F-RNA coliphage MS2 and murine norovirus (MNV), which are surrogates for norovirus, was significantly greater when oral fluid was incubated for 24h at 4°C than when oral fluid was stabilized with RNAprotect Saliva Reagent for 24h at 37°C, where the relative differences between the two processes were 1.4, 1.8, and 2.7 log genome copies/ml for MS2, MNV, and HEV, respectively. The findings suggest that it is unnecessary to stabilize oral fluid from swine for the detection of viral RNA, provided the samples are stored at 4°C or frozen at -20°C, and that the RNeasy Protect Saliva Mini kit did not perform well for the detection of viral RNA.


Asunto(s)
Boca/virología , ARN Viral/genética , Animales , Infecciones por Caliciviridae/genética , Excipientes , Hepatitis E/genética , Virus de la Hepatitis E/genética , Calor , Ratones , Norovirus/genética , Manejo de Especímenes/métodos , Porcinos
13.
Eur J Endocrinol ; 170(2): 193-200, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24165020

RESUMEN

CONTEXT: The TIMES2 (testosterone replacement in hypogonadal men with either metabolic syndrome or type 2 diabetes) study reported beneficial effects of testosterone replacement therapy (TRT) on insulin resistance and other variables in men with diabetes or metabolic syndrome. The androgen receptor CAG repeat polymorphism (AR CAG) is known to affect stimulated AR activity and has been linked to various clinically relevant variables. OBJECTIVE: To assess the role of AR CAG in the alteration of clinical response to TRT in the TIMES2 study. DESIGN: Subgroup analysis from a multicentre, randomised, double-blind, placebo-controlled and parallel group study. SETTING: Outpatient study recruiting from secondary and primary care. PATIENTS: A total of 139 men with hypogonadism and type 2 diabetes or metabolic syndrome, of which 73 received testosterone during the TIMES2 study. INTERVENTION: Testosterone 2% transdermal gel vs placebo. MAIN OUTCOME MEASURE: Regression coefficient of AR CAG from linear regression models for each variable. RESULTS: AR CAG was independently positively associated with change in fasting insulin, triglycerides and diastolic blood pressure during TRT with a trend to association with HOMA-IR - the primary outcome variable. There was a trend to negative association between AR CAG and change in PSA. There was no association of AR CAG with change in other glycaemic variables, other lipid variables or obesity. CONCLUSION: AR CAG affected the response of some variables to TRT in the TIMES2 study, although the association with HOMA-IR did not reach significance. Various factors may have limited the power of our study to detect the significant associations between AR CAG, testosterone levels and change in variables with testosterone treatment. Analysis of similar data sets from other clinical trials is warranted.


Asunto(s)
Diabetes Mellitus Tipo 2/tratamiento farmacológico , Síndrome Metabólico/tratamiento farmacológico , Receptores Androgénicos/genética , Testosterona/uso terapéutico , Adulto , Terapia de Reemplazo de Hormonas , Humanos , Hipogonadismo/tratamiento farmacológico , Resistencia a la Insulina , Masculino , Síndrome Metabólico/genética , Polimorfismo Genético , Repeticiones de Trinucleótidos
14.
Water Res ; 47(16): 6244-57, 2013 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-24075721

RESUMEN

Over 3500 individual water samples, for 131 sampling times, targeting waterborne pathogens/fecal indicator bacteria were collected during a 7-year period from 4 sites along an intermittent stream running through a small livestock pasture system with and without cattle access-to-stream restriction measures. The study assessed the impact of cattle pasturing/riparian zone protection on: pathogen (bacterial, viral, parasite) occurrence, concentrations of fecal indicators, and quantitative microbial risk assessments (QMRA) of the risk of Cryptosporidium, Giardia and Escherichia coli O157:H7 infection in humans. Methodologies were developed to compute QMRA mean risks on the basis of water samples exhibiting potentially human infectious Cryptosporidium and E. coli based on genotyping Crytosporidium, and E. coli O157:H7 presence/absence information paired with enumerated E. coli. All Giardia spp. were considered infectious. No significant pasturing treatment effects were observed among pathogens, with the exception of Campylobacter spp. and E. coli O157:H7. Campylobacter spp. prevalence significantly decreased downstream through pasture treatments and E. coli O157:H7 was observed in a few instances in the middle of the unrestricted pasture. Densities of total coliform, fecal coliform, and E. coli reduced significantly downstream in the restricted pasture system, but not in the unrestricted system. Seasonal and flow conditions were associated with greater indicator bacteria densities, especially in the summer. Norovirus GII was detected at rates of 7-22% of samples for all monitoring sites, and rotavirus in 0-7% of samples for all monitoring sites; pasture treatment trends were not evident, however. Seasonal and stream flow variables (and their interactions) were relatively more important than pasture treatments for initially stratifying pathogen occurrence and higher fecal indicator bacteria densities. Significant positive associations among fecal indicator bacteria and Campylobacter spp. detection were observed. For QMRA, adjusting for the proportion of Cryptosporidium spp. detected that are infectious for humans reduces downstream risk estimates by roughly one order of magnitude. Using QMRA in this manner provides a more refined estimate of beneficial management practice effects on pathogen exposure risks to humans.


Asunto(s)
Fenómenos Fisiológicos Bacterianos , Parásitos/fisiología , Ríos , Fenómenos Fisiológicos de los Virus , Microbiología del Agua , Crianza de Animales Domésticos , Animales , Carga Bacteriana , Bovinos , Humanos , Densidad de Población , Prevalencia , Medición de Riesgo , Ríos/microbiología , Ríos/parasitología , Ríos/virología , Estaciones del Año , Movimientos del Agua , Zoonosis/epidemiología
15.
J Food Prot ; 75(12): 2142-50, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23212010

RESUMEN

In Canada, there is a zero tolerance for Listeria in a 125-g sample of product in which growth of Listeria monocytogenes can occur, and a limit of ≤100 CFU/g in ready-to-eat (RTE) food products that support limited growth during the stated shelf life and/or RTE refrigerated foods with a shelf life of ≤5 days. L. monocytogenes can form filaments in response to pH and osmotic, atmospheric, and temperature stress, which can result in an underestimation of the risk of RTE foods as filaments form single colonies on plate count agars but can divide into individual cells once the stress is removed. The objective was to investigate the filamentation characteristics of three strains of L. monocytogenes exposed to saline, acidic, basic, and simultaneous acidic and saline environments at 3°C. After 4 days at 3°C, log-phase cells grown in tryptic soy broth (TSB) were longer than cells grown at 15°C, and 68% of cells were below the reference value of the 90th percentile of control cultures. When cultures growing at 3°C were exposed to additional stresses, increases in the proportion and length of filaments in the population were observed, while increases in log CFU per milliliter were reduced. After 4 days of incubation at 3°C, the log CFU per milliliter of L. monocytogenes increased by 1.1 U in TSB and 0.4 to 0.5 U in TSB with 4% NaCl, TSB with a pH of 6.0 with 4% NaCl, and TSB with a pH of 5.5. Moreover, the longest 10% of cells were 6.4 to 8.5 times longer than control cells, and only 20 to 30% of cells were below the reference value. Cultures grown in TSB at pH 6.0 with 4% NaCl experienced more sustained filamentation than cultures grown in TSB with 4% NaCl, but less than cultures grown in TSB at pH 6.0. The mechanism involved in filamentation could be different for cells exposed to NaCl than exposed to acid, and additional stress might not necessarily result in more extensive filament formation. These findings contribute to a better understanding of the widespread potential of filament formation and the potential implications for food safety.


Asunto(s)
Adaptación Fisiológica , Contaminación de Alimentos/análisis , Manipulación de Alimentos/métodos , Microbiología de Alimentos , Listeria monocytogenes/crecimiento & desarrollo , Recuento de Colonia Microbiana , Contaminación de Alimentos/prevención & control , Inocuidad de los Alimentos , Humanos , Concentración de Iones de Hidrógeno , Cinética , Modelos Biológicos , Concentración Osmolar , Temperatura , Factores de Tiempo
16.
Int J Food Microbiol ; 159(3): 193-7, 2012 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-23107497

RESUMEN

The existence of animal strains of norovirus (NV) that are closely related to human strains raises concerns about interspecies recombination and the potential for zoonotic transmission through undercooked meat products. Contamination of meat with NV can occur both via meat processing operations and poor food handler hygiene. There is a lack of knowledge on the survival of NV on raw meat because NV cannot be effectively cultivated and its detection is limited to molecular methods. The survival of murine norovirus (MNV) and MS2, as surrogates for NV, was determined on pork chops by plaque assay and real time RT-PCR. Both MNV and MS2 displayed very high survival rates on vacuum packaged raw pork chops that were stored at 2°C for up to 7 weeks and numbers declined little during subsequent retail display for 7 days. Maximum reductions for MNV and MS2 were 1.0 log PFU/cm(2) and 0.6 log genome copies(GC)/cm(2) or 1.1 log PFU/cm(2) and 1.2 log GC/cm(2), respectively. The viability of MS2 and MNV was not affected by the proteolytic enzymes present in the meat nor by numbers of bacteria that increased with time during storage in vacuum packs and while on retail display. MNV and MS2 can be considered as good surrogates for NV on raw meat. The findings of this study indicate that potentially pathogenic NV will likely survive extremely well on fresh meat and consumers could potentially be at risk when consuming undercooked meat that is contaminated with NV.


Asunto(s)
Manipulación de Alimentos , Microbiología de Alimentos , Levivirus/fisiología , Carne/virología , Norovirus/fisiología , Animales , Concentración de Iones de Hidrógeno , Levivirus/genética , Norovirus/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Supervivencia , Porcinos , Temperatura
17.
J Food Prot ; 75(8): 1492-500, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22856576

RESUMEN

Hepatitis E virus (HEV) is common in pigs, and some swine HEV strains are closely related to human strains. The zoonotic transmission of HEV is now well established. HEV can be detected by molecular techniques, but the significance of the presence of viral nucleic acid is questionable when foods are subjected to virus inactivation treatments. F-RNA coliphages are attractive candidates as indicators for enteric viruses because they are similar in size and survival characteristics and can be rapidly cultured. Information on the contamination of hog carcasses with enteric or hepatic viruses during slaughter is lacking. The objective of this study was to compare the incidence and levels of contamination of hog carcasses with F-RNA coliphages, HEV, total aerobic bacteria, coliforms, and Escherichia coli at different stages of the dressing process. Hog carcasses entering the commercial slaughter facility are heavily contaminated with F-RNA coliphages and HEV. Subsequent processes such as scalding, singing, and pasteurization can reduce the incidence and levels of F-RNA coliphages and HEV substantially to almost undetectable levels. Large discrepancies between the amount of viral nucleic acid and infectious F-RNA coliphage particles, both at high levels and low levels of contamination, were observed. The prevalence and levels of viable F-RNA coliphages were lower than those of total aerobic bacteria, coliforms, and E. coli in the anal area and on random sites before pasteurization. At a research abattoir, there was no overall mean reduction of viable F-RNA coliphages recovered from random sites before pasteurization and after washing, whereas overall mean reductions of 1.2, 2.6, and 2.9 log CFU for total aerobic bacteria, coliforms, and E. coli, respectively, were obtained. These findings suggest that bacteria such as coliforms and E. coli may not be suitable as indicators for enteric viruses in a meat processing environment.


Asunto(s)
Colifagos/aislamiento & purificación , Contaminación de Alimentos/análisis , Industria de Procesamiento de Alimentos/métodos , Virus de la Hepatitis E/aislamiento & purificación , Porcinos/microbiología , Animales , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Microbiología de Alimentos , Humanos , Prevalencia , Porcinos/virología
18.
J Environ Qual ; 41(4): 1301-14, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22751075

RESUMEN

This 5-yr study compared, via an upstream-downstream experimental design, nutrient and microbial water quality of an intermittent stream running through a small pasture (∼2.5 animals ha) where cattle are restricted from the riparian zone (restricted cattle access [RCA]) and where cattle have unrestricted access to the stream (unrestricted cattle access [URCA]). Fencing in the RCA excluded pasturing cattle to within ∼3 to 5 m of the stream. Approximately 88% (26/32) of all comparisons of mean contaminant load reduction for lower, higher, and all stream flow conditions during the 5-yr study indicated net contaminant load reductions in the RCA; for the URCA, this percentage was 38% (12/32). For all flow conditions, mean percent load reductions in the RCA for nutrients and bacteria plus F-coliphage were 24 and 23%, respectively. These respective percentages for the URCA were -9 and -57% (positive values are reductions; negative values are increases). However, potentially as a result of protected wildlife habitat in the RCA, the mean percent load reduction for for "all flow" was -321% for the RCA and 60% for the URCA; for , these respective percentages were -209% (RCA) and 73% (URCA). For "all flow" situations, mean load reductions for the RCA were significantly greater ( < 0.1) than those from the URCA for NH-N, dissolved reactive phosphorus (DRP), total coliform, , and . For "high flow" situations, mean load reductions were significantly greater for the RCA for DRP, total coliform, and . For "low flow" conditions, significantly greater mean load reductions were in favor of the RCA for DRP, total P, total coliforms, fecal coliforms, , and . In no case were mean pollutant loads in the URCA significantly higher than RCA pollutant loads. Restricting pasturing livestock to within 3 to 5 m of intermittent streams can improve water quality; however, water quality impairment can occur if livestock have unrestricted access to a stream.


Asunto(s)
Bacterias/aislamiento & purificación , Bovinos , Ríos/química , Ríos/microbiología , Contaminantes del Agua , Agua/química , Crianza de Animales Domésticos , Animales , Colifagos/aislamiento & purificación , Monitoreo del Ambiente , Sedimentos Geológicos/microbiología , Nitrógeno/química , Fósforo/química , Microbiología del Suelo , Microbiología del Agua , Contaminación del Agua/prevención & control
19.
J Virol Methods ; 185(1): 69-73, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22705082

RESUMEN

F-RNA coliphages, part of the gut flora and likely to be deposited on meat along with other enteric organisms during carcass dressing and processing, may be regarded as an indicator and/or surrogate for potential zoonotic enteric viruses. There is no recommended sampling method for viruses on meats and there is a lack of information on the attachment of enteric viruses or F-RNA coliphages to gauze swabs, cellulose sponges and muscle and fat tissue. The objective of this work was to optimize the recovery of MS2 from muscle and fat tissue of meat by comparing phosphate buffered saline (PBS), 10% beef extract pH 7.2, and tryptose phosphate (2.9%) glycine (6%) broth pH 9.5 as eluants. The sampling techniques of excision, swabbing with gauze or cellulose sponges were compared with homogenizing the inoculated entire muscle or fat surface area. The recovery of MS2 from cellulose sponges using beef extract was significantly higher (P=0.001) than tryptose phosphate glycine broth which was significantly higher (P=0.0001) than PBS. There was no significant difference in the recovery between tryptose phosphate glycine broth and beef extract (P=0.92) and there was no significant difference between PBS and beef extract (P=0.10) when MS2 was recovered from gauze. No significant differences were observed between the different eluants with muscle tissue (P=0.91). When MS2 was recovered from muscle tissue with beef extract significant differences were observed (P=0.002); the sampling techniques of homogenizing the entire sample (56%) was equal to excision (43%) (P=0.23) and swabbing with a cellulose sponge (38%) (P=0.06) which were significantly higher than swabbing with gauze (28%), a second grouping of means indicated that homogenizing the entire sample was significantly higher than the other three sampling techniques. When MS2 was recovered from fat, significant differences were observed (P=0.000); homogenizing the entire sample (78%) was equal to excision (74%), which were significantly higher than swabbing with gauze (49%) or cellulose sponge (29%). The recovery of MS2 from meat is affected by the sampling technique. When choosing a nondestructive sampling method such as a cellulose sponge, a higher recovery can be obtained with beef extract as an eluant.


Asunto(s)
Análisis de los Alimentos/métodos , Industria de Alimentos/métodos , Levivirus/aislamiento & purificación , Carne/virología , Manejo de Especímenes/métodos , Virología/métodos , Humanos , Sensibilidad y Especificidad
20.
Clin Endocrinol (Oxf) ; 74(5): 624-30, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21470285

RESUMEN

OBJECTIVE: There is a high prevalence of low testosterone and dyslipidaemia in men with type 2 diabetes. The androgen receptor CAG repeat polymorphism (AR CAG) affects receptor transcriptional activity (the shorter repeats the more sensitive AR) and is associated with androgenic parameters and obesity. This study describes the relationships between testosterone, AR CAG and serum lipids in men with type 2 diabetes. DESIGN AND PATIENTS: Cross-sectional study of men with type 2 diabetes in a District General Hospital Diabetes Centre. MEASUREMENTS: Correlation between testosterone, AR CAG and serum lipids. RESULTS: HDL cholesterol (HDL-C) correlated with total testosterone (TT) (r = 0·251, P < 0·001), bioavailable testosterone (BT) (r = 0·19, P = 0·001), free testosterone (FT) (r = 0·165, P = 0·005) and sex hormone-binding globulin (SHBG) (r = 0·147, P = 0·014). HDL-C did not correlate with oestradiol, but men with the lowest quartile of oestradiol had lower HDL-C compared to highest quartile (P = 0·046). Triglycerides correlated negatively with TT (r = -0·195, P = 0·001), BT (r = -0·148, P = 0·013) and SHBG (-0·14, P = 0·019) but not with FT or oestradiol. Total and LDL cholesterol (LDL-C) correlated negatively with oestradiol (r = -0·121, P = 0·05) but not with testosterone or SHBG. One-way anova testing across four quartiles of AR CAG showed a trend to alteration in HDL-C across groups of AR CAG (P = 0·08). HDL-C was significantly higher in men with the longest AR CAG compared with the shortest (1·19 vs 1·08 mmol/l, P = 0·02). CONCLUSIONS: Lower testosterone and oestradiol levels in men with diabetes are associated with an adverse lipid profile. Shorter AR CAG is associated with low HDL-C and testosterone. The paradox that HDL-C is associated with low testosterone levels and a more active AR may suggest divergent effect of testosterone on HDL-C via genomic vs nongenomic mechanisms.


Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Dislipidemias/etiología , Estradiol/sangre , Receptores Androgénicos/genética , Testosterona/sangre , Repeticiones de Trinucleótidos , Anciano , HDL-Colesterol/sangre , Estudios Transversales , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo Genético
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