RESUMO
BACKGROUND: Aggressive behaviours are common in people with neurodevelopmental conditions, contributing to poorer quality of life and placement breakdown. However, there is limited empirical research documenting the prevalence and persistence of aggressive behaviours in autism. In this longitudinal study, aggressive behaviours were investigated in a sample of autistic individuals over 10 years. METHODS: Caregivers of autistic individuals, both with and without intellectual disability, completed questionnaires relating to the presence of aggressive behaviours at T1 [N = 229, mean age in years 11.8, standard deviation (SD) 5.9], T2 (T1 + 3 years, N = 81, mean age in years 15.1, SD 5.9) and T3 (T1 + 10 years, N = 54, mean age in years 24.5, SD 8.1). Analyses examined the presence and persistence of aggressive behaviours and the predictive value of established correlates of aggression. RESULTS: Aggressive behaviours were common at baseline (61.6%) but only persistent in 30% of the sample over 10 years. Higher composite scores of overactivity and impulsivity at T1 were significantly associated with the persistence of aggressive behaviours at T2 (P = 0.027) and T3 (P = 0.012) with medium effect size. CONCLUSIONS: Aggressive behaviours are common in autism, but reduce with age. Behavioural correlates of attention deficit hyperactivity disorder (ADHD) predict the presence and persistence of aggressive behaviour and as such may be useful clinical indicators to direct proactive intervention resources to ameliorate aggressive behaviours.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Transtorno Autístico , Deficiência Intelectual , Humanos , Transtorno Autístico/epidemiologia , Estudos Longitudinais , Qualidade de Vida , Agressão , Deficiência Intelectual/epidemiologiaRESUMO
AIM: To evaluate the occurrence and severity of allergic reactions to iodinated contrast media (ICM), including associated risk factors and the impact of pre-medication. MATERIALS AND METHODS: Data on patients who had experienced allergic reactions during outpatient computed tomography (CT) examinations between January 2014 and September 2018 were analysed retrospectively. Response severity was assessed according to validated criteria. A control group was selected among individuals who underwent CT during the study period and did not experience allergic reactions. RESULTS: Screening of 36,920 CT studies revealed 74 (0.2%) individuals with systemic reactions to ICM. No significant differences in patient characteristics were found among patients who experienced mild (n=54), moderate (n=17), or severe (n=4) reactions. Previous ICM allergy was reported in 10 patients (13.3%). Patients with a history of ICM allergy had mild (9/10) or moderate (1/10) reactions, with one individual showing decreased intensity of the allergic response compared to a previous event. Within the control group, four patients (4%) had previous ICM allergy. In these individuals, lack of allergic reactions could not be attributed to pre-medication. All patients with severe reactions did not have a prior history of ICM allergy. CONCLUSION: Severe allergic reactions to ICM are rare, lack significant risk factors, and do not appear to be impacted by pre-medication. The findings presented herein highlight the need for prospective work that will re-evaluate the yield of pre-medication protocols.
Assuntos
Meios de Contraste/efeitos adversos , Hipersensibilidade a Drogas/etiologia , Iodo/efeitos adversos , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Estudos de Casos e Controles , Meios de Contraste/química , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Concentração Osmolar , Pré-Medicação , Estudos Retrospectivos , Fatores de Risco , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Adulto JovemRESUMO
OBJECTIVES: To assess the cost-effectiveness of uterine artery embolisation (UAE) and myomectomy for women with symptomatic uterine fibroids wishing to avoid hysterectomy. DESIGN: Economic evaluation alongside the FEMME randomised controlled trial. SETTING: 29 UK hospitals. POPULATION: Premenopausal women who had symptomatic uterine fibroids amenable to UAE or myomectomy wishing to avoid hysterectomy. 254 women were randomised to UAE (127) and myomectomy (127). METHODS: A within-trial cost-utility analysis was conducted from the perspective of the UK NHS. MAIN OUTCOME MEASURES: Quality-adjusted life years (QALYs) measured using the EuroQoL EQ-5D-3L, combined with costs to estimate cost-effectiveness over 2 and 4 years of follow-up. RESULTS: Over a 2-year time horizon, UAE was associated with higher mean costs (difference £645; 95% CI -1381 to 2580) and lower QALYs (difference -0.09; 95% CI -0.11 to -0.04) when compared with myomectomy. Similar results were observed over the 4-year time horizon. Thus, UAE was dominated by myomectomy. Results of the sensitivity analyses were consistent with the base case results for both years. Over 2 years, UAE was associated with higher costs (difference £456; 95% CI -1823 to 3164) and lower QALYs (difference -0.06; 95% CI -0.11 to -0.02). CONCLUSIONS: Myomectomy is a cost-effective option for the treatment of uterine fibroids. The differences in costs and QALYs are small. Women should be fully informed and have the option to choose between the two procedures. TWEETABLE ABSTRACT: Fully informed women with uterine fibroids should have a choice between uterine artery embolisation or myomectomy.
Assuntos
Leiomioma/cirurgia , Embolização da Artéria Uterina/economia , Miomectomia Uterina/economia , Neoplasias Uterinas/cirurgia , Adulto , Análise Custo-Benefício , Feminino , Humanos , Leiomioma/economia , Pessoa de Meia-Idade , Pré-Menopausa , Anos de Vida Ajustados por Qualidade de Vida , Resultado do Tratamento , Neoplasias Uterinas/economiaRESUMO
BACKGROUND: Tuberous sclerosis complex (TSC) is a hamartoma syndrome characterized by multiple skin lesions, such as angiofibromas, shagreen patch and miliary fibromas (MiF). OBJECTIVE: To determine the clinical and histological features of MiF. METHODS: A retrospective analysis was conducted on 133 adults with TSC. Photography was used to characterize the appearance and location of MiF. Histological features in five skin samples from four individuals were evaluated by a board-certified dermatopathologist. RESULTS: MiF were observed in 19 of 133 (14%) individuals with TSC. MiF were 1- to 3-mm skin-coloured, sessile papules scattered on the back and rarely buttocks or thighs. Most were scattered in a bilaterally symmetric distribution, but others were asymmetric or associated with a shagreen patch. Histological features of MiF included expansion of the papillary and periadnexal dermis with variable hamartomatous abnormalities involving adjacent epithelial components. CONCLUSIONS: MiF are distinct from other cutaneous lesions in TSC such as shagreen patches and angiofibromas. Recognition of this entity is important in defining the spectrum of TSC disease and reassuring individuals with TSC that these lesions are benign.
Assuntos
Angiofibroma , Fibroma , Nevo , Esclerose Tuberosa , Adulto , Humanos , Estudos Retrospectivos , Esclerose Tuberosa/complicaçõesRESUMO
BACKGROUND: Cornelia de Lange syndrsome (CdLS) is a rare genetic syndrome with notable impaired expressive communication characterised by reduced spoken language. We examined gesture use to refine the description of expressive communication impairments in CdLS. METHODS: During conversations, we compared gesture use in people with CdLS to peers with Down syndrome (DS) matched for receptive language and adaptive ability, and typically developing (TD) individuals of similar chronological age. RESULTS: As anticipated the DS and CdLS groups used fewer words during conversation than TD peers (P < .001). However, the CdLS group used twice the number of gestures per 100 words compared with the DS and TD groups (P = .003). CONCLUSIONS: Individuals with CdLS have a significantly higher gesture rate than expected given their level of intellectual disability and chronological age. This result indicates the cause of reduced use of spoken language does not extend to all forms of expressive communication.
Assuntos
Síndrome de Cornélia de Lange , Síndrome de Down , Deficiência Intelectual , Síndrome de Cornélia de Lange/genética , Gestos , Humanos , FalaRESUMO
BACKGROUND: Tumor-derived circulating cell-free DNA (cfDNA) is present in the plasma of individuals with cancer. Assays aimed at detecting common cancer mutations in cfDNA are being developed for the detection of several cancer types. In breast cancer, however, such assays have failed to detect the disease at a sensitivity relevant for clinical use, in part due to the absence of multiple common mutations that can be co-detected in plasma. Unlike individual mutations that exist only in a subset of tumors, unique DNA methylation patterns are universally present in cells of a common type and therefore may be ideal biomarkers. Here we describe the detection and quantification of breast-derived cfDNA using a breast-specific DNA methylation signature. PATIENTS AND METHODS: We collected plasma from patients with localized breast cancer before and throughout treatment with neoadjuvant chemotherapy and surgery (N = 235 samples). RESULTS: Pretreatment breast cfDNA was detected in patients with localized disease with a sensitivity of 80% at 97% specificity. High breast cfDNA levels were associated with aggressive molecular tumor profiles and metabolic activity of the disease. During neoadjuvant chemotherapy, breast cfDNA levels decreased dramatically. Importantly, the presence of breast cfDNA towards the end of the chemotherapy regimen reflected the existence of residual disease. CONCLUSION: We propose that breast-specific cfDNA is a universal and powerful marker for the detection and monitoring of breast cancer.
Assuntos
Neoplasias da Mama , Ácidos Nucleicos Livres , Biomarcadores Tumorais/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Ácidos Nucleicos Livres/genética , DNA , Metilação de DNA , DNA de Neoplasias/genética , Humanos , MutaçãoRESUMO
OBJECTIVES: The objective of this study was to evaluate the spatial relationship between colorectal cancer (CRC) mortality and ambulatory surgery center (ASC) density in Pennsylvania's 67 counties. STUDY DESIGN: This was an ecological study. METHODS: Age-adjusted CRC mortality rates were linked to ASC densities per 1,000 people. The data set was analyzed using global, local, and regional Moran's I, to test for randomness in CRC mortality and ASC density. RESULTS: CRC mortality rates (median: 15.30 per 100,000 of the US 2000 standard million population) exhibited hot spots in rural Pennsylvania counties. ASC densities (median: 0.35 providers/km2 per 1,000 people) showed hot spots in urban southeastern Pennsylvania and cold spots in northern Pennsylvania. CONCLUSIONS: CRC mortality rates tended to cluster in rural northern Pennsylvania counties; ASC density tended to cluster in urban southeastern counties, indicating a spatial disparity between needed and provided healthcare resources. There is a need for public health and health system changes to increase the availability of CRC services to rural communities.
Assuntos
Instituições de Assistência Ambulatorial/estatística & dados numéricos , Neoplasias Colorretais/mortalidade , Procedimentos Cirúrgicos Ambulatórios/estatística & dados numéricos , Colonoscopia/estatística & dados numéricos , Neoplasias Colorretais/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pennsylvania/epidemiologia , População Rural/estatística & dados numéricos , Estados Unidos/epidemiologia , População Urbana/estatística & dados numéricosRESUMO
BACKGROUND: Hyperactivity and repetitive behaviour are characteristic features of fragile X syndrome (FXS). However, little is known about the influence of autism symptomatology on how these characteristics develop over time. We investigate the profiles and developmental trajectories of overactivity, impulsivity and repetitive behaviour, in males with FXS over three time points spanning 8 years. METHOD: Participants formed two subgroups, those who displayed elevated symptoms of autism at Time 1 (n = 37; Mage = 16.32; age range = 6.61-43.51) and those who did not (n = 32; Mage = 8.43; age range = 8.94-47.49). RESULTS: Participants without elevated symptoms of autism showed a reduction in impulsivity and repetitive questioning over time, whereas those with elevated symptoms of autism did not. Differences between the two subgroups in several topographies of repetitive behaviour emerged at Time 3 only. CONCLUSIONS: These results further understanding of the relationship between autistic phenomenology and behavioural characteristics in FXS.
Assuntos
Transtorno Autístico/epidemiologia , Transtornos Disruptivos, de Controle do Impulso e da Conduta/epidemiologia , Síndrome do Cromossomo X Frágil/epidemiologia , Agitação Psicomotora/epidemiologia , Transtorno de Movimento Estereotipado/epidemiologia , Adolescente , Adulto , Comorbidade , Humanos , Masculino , Estudos Prospectivos , Reino Unido , Adulto JovemRESUMO
BACKGROUND: Catatonia-like presentations in people with autism have been increasingly recognised within research and diagnostic guidelines. The recently developed Attenuated Behaviour Questionnaire has identified that attenuated behaviour [autistic catatonia] is very prevalent in people with autism spectrum disorders (ASDs) and associated with repetitive behaviour. In the current study, we investigated attenuated behaviour within two genetic syndromes associated with ASD and examined ASD and repetitive behaviour as longitudinal predictors of attenuated behaviour. METHOD: The Attenuated Behaviour Questionnaire was completed by parents/carers of 33 individuals with Cornelia de Lange syndrome (CdLS) and 69 with fragile X syndrome (FXS). Information collected from the same informants 4 years previously was utilised to examine ASD and repetitive behaviour as predictors of later attenuated behaviour, controlling for age, gender and ability. RESULTS: Catatonia-like attenuated behaviour was reported for individuals with CdLS (30.3%) and FXS (11.6%). Slowed movement was more prevalent in people with CdLS. No other phenotypic differences were observed. Across the two groups, repetitive behaviour predicted the presence of attenuated behaviour 4 years later, after controlling for age, gender and ability. CONCLUSIONS: Attenuated behaviour can be identified in individuals with CdLS and FXS and may have an effect on both adaptive behaviour and quality of life. Repetitive behaviours predicted subsequent risk within both groups and should be assessed by services as part of a pro-active strategy of support.
Assuntos
Transtorno do Espectro Autista/epidemiologia , Catatonia/epidemiologia , Síndrome de Cornélia de Lange/epidemiologia , Síndrome do Cromossomo X Frágil/epidemiologia , Transtorno de Movimento Estereotipado/epidemiologia , Adolescente , Adulto , Transtorno do Espectro Autista/fisiopatologia , Cuidadores , Catatonia/fisiopatologia , Criança , Comorbidade , Síndrome de Cornélia de Lange/fisiopatologia , Feminino , Síndrome do Cromossomo X Frágil/fisiopatologia , Humanos , Irlanda/epidemiologia , Masculino , Pessoa de Meia-Idade , Transtorno de Movimento Estereotipado/fisiopatologia , Inquéritos e Questionários , Reino Unido/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Individuals with tuberous sclerosis complex (TSC) are at increased risk of developing self-injurious behaviour. The persistence of this deleterious behaviour over years is reported in aetiologically heterogeneous samples to be between 60% and 80% but is unknown for TSC. METHOD: In this study, we determined the 3-year persistence of self-injury in a sample (n = 52) of children (with and without ID) and adults (with ID) with TSC and examined characteristics associated with persistence. RESULTS: Findings for self-injury were contrasted to those for aggression and property destruction to examine the specificity of results to this behaviour. Self-injury was persistent in 84.6% of those with TSC who showed this behaviour, in contrast to 66.7% both for aggression and destruction. Persistent self-injury was associated with poor self-help skills, greater overactivity/impulsivity and more behavioural indicators of pain. These latter two characteristics were also associated with persistent aggression. No characteristics were associated with persistence of property destruction. CONCLUSION: These findings suggest that self-injurious behaviours in individuals with TSC, together with aggressive and destructive behaviours, are highly persistent and would benefit from targeted intervention. Poor adaptive skills, overactivity/impulsivity and painful health conditions may differentiate those at most risk for persistent self-injury or aggression.
Assuntos
Agressão/psicologia , Deficiência Intelectual/epidemiologia , Comportamento Problema/psicologia , Comportamento Autodestrutivo/epidemiologia , Esclerose Tuberosa/epidemiologia , Adolescente , Adulto , Comorbidade , Feminino , Humanos , Deficiência Intelectual/psicologia , Masculino , Comportamento Autodestrutivo/psicologia , Esclerose Tuberosa/psicologia , Reino Unido/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Recent research suggests that around 16% to 18% of children with Down syndrome (DS) also meet diagnostic criteria for autism spectrum disorder (ASD). However, there are indications that profiles of autism symptoms in this group may vary from those typically described in children with ASD. METHOD: Rates of autism symptoms and emotional and behavioural problems among children with DS who screened positive for ASD on the Social Communication Questionnaire (SCQ) (n = 183) were compared with a group of children with clinical diagnoses of ASD (n = 189) attending specialist schools in the UK. Groups were matched for age and approximate language level (use of phrase speech). RESULTS: Profiles of autistic symptoms in the two groups were generally similar, but children with DS meeting ASD cut-off on the SCQ tended to show fewer problems in reciprocal social interaction than those in the ASD group. They also showed slightly lower rates of emotional and peer-related problems. The results mostly confirm findings from a previous study in which the original validation sample for the SCQ was used as a comparison group. CONCLUSION: Findings suggest that children with DS who meet screening criteria for ASD show similar profiles of communication and repetitive behaviours to those typically described in autism. However, they tend to have relatively milder social difficulties. It is important that clinicians are aware of this difference if children with DS and ASD are to be correctly diagnosed and eligible for specialist intervention and education services.
Assuntos
Transtorno do Espectro Autista/epidemiologia , Transtorno do Espectro Autista/fisiopatologia , Síndrome de Down/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Comorbidade , Educação Inclusiva/estatística & dados numéricos , Feminino , Humanos , Masculino , Reino Unido/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Methylnaltrexone (MNTX), a peripherally acting µ-opioid receptor (MOR) antagonist, is FDA-approved for treatment of opioid-induced constipation (OIC). Preclinical data suggest that MOR activation can play a role in cancer progression and can be a target for anticancer therapy. PATIENTS AND METHODS: Pooled data from advanced end-stage cancer patients with OIC, despite laxatives, treated in two randomized (phase III and IV), placebo-controlled trials with MNTX were analyzed for overall survival (OS) in an unplanned post hoc analysis. MNTX or placebo was given subcutaneously during the double-blinded phase, which was followed by the open-label phase, allowing MNTX treatment irrespective of initial randomization. RESULTS: In two randomized, controlled trials, 229 cancer patients were randomized to MNTX (117, 51%) or placebo (112, 49%). Distribution of patients' characteristics and major tumor types did not significantly differ between arms. Treatment with MNTX compared with placebo [76 days, 95% confidence interval (CI) 43-109 versus 56 days, 95% CI 43-69; P = 0.033] and response (laxation) to treatment compared with no response (118 days, 95% CI 59-177 versus 55 days, 95% CI 40-70; P < 0.001) had a longer median OS, despite 56 (50%) of 112 patients ultimately crossing over from placebo to MNTX. Multivariable analysis demonstrated that response to therapy [hazard ratio (HR) 0.47, 95% CI 0.29-0.76; P = 0.002) and albumin ≥3.5 (HR 0.46, 95% CI 0.30-0.69; P < 0.001) were independent prognostic factors for increased OS. Of interest, there was no difference in OS between MNTX and placebo in 134 patients with advanced illness other than cancer treated in these randomized studies (P = 0.88). CONCLUSION: This unplanned post hoc analysis of two randomized trials demonstrates that treatment with MNTX and, even more so, response to MNTX are associated with increased OS, which supports the preclinical hypothesis that MOR can play a role in cancer progression. Targeting MOR with MNTX warrants further investigation in cancer therapy. CLINICAL TRIALS NUMBER: NCT00401362, NCT00672477.
Assuntos
Constipação Intestinal/tratamento farmacológico , Naltrexona/análogos & derivados , Neoplasias/tratamento farmacológico , Adulto , Idoso , Analgésicos Opioides/uso terapêutico , Constipação Intestinal/complicações , Constipação Intestinal/fisiopatologia , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Laxantes/administração & dosagem , Masculino , Pessoa de Meia-Idade , Naltrexona/administração & dosagem , Neoplasias/complicações , Neoplasias/fisiopatologia , Compostos de Amônio Quaternário/administração & dosagem , Receptores Opioides mu/antagonistas & inibidoresRESUMO
The neuropeptide oxytocin (OXT) exerts anxiolytic and prosocial effects in the central nervous system of rodents. A number of recent studies have attempted to translate these findings by investigating the relationships between peripheral (e.g., blood, urinary and salivary) OXT concentrations and behavioral functioning in humans. Although peripheral samples are easy to obtain in humans, whether peripheral OXT measures are functionally related to central OXT activity remains unclear. To investigate a possible relationship, we quantified OXT concentrations in concomitantly collected cerebrospinal fluid (CSF) and blood samples from child and adult patients undergoing clinically indicated lumbar punctures or other CSF-related procedures. Anxiety scores were obtained in a subset of child participants whose parents completed psychometric assessments. Findings from this study indicate that plasma OXT concentrations significantly and positively predict CSF OXT concentrations (r=0.56, P=0.0064, N=27). Moreover, both plasma (r=-0.92, P=0.0262, N=10) and CSF (r=-0.91, P=0.0335, N=10) OXT concentrations significantly and negatively predicted trait anxiety scores, consistent with the preclinical literature. Importantly, plasma OXT concentrations significantly and positively (r=0.96, P=0.0115, N=10) predicted CSF OXT concentrations in the subset of child participants who provided behavioral data. This study provides the first empirical support for the use of blood measures of OXT as a surrogate for central OXT activity, validated in the context of behavioral functioning. These preliminary findings also suggest that impaired OXT signaling may be a biomarker of anxiety in humans, and a potential target for therapeutic development in individuals with anxiety disorders.
Assuntos
Ansiedade/sangue , Ansiedade/líquido cefalorraquidiano , Ocitocina/sangue , Ocitocina/líquido cefalorraquidiano , Adolescente , Adulto , Ansiedade/psicologia , Biomarcadores/sangue , Biomarcadores/líquido cefalorraquidiano , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Valor Preditivo dos Testes , Estatística como Assunto , Adulto JovemRESUMO
A retrospective review of 98 cases of complicated cataract surgery and/or delayed intraocular lens (IOL) dislocation examined the relationship between vitrectomy and cataract surgery complications. Nine (9.2%) of the 98 patients had a history of vitrectomy, before or after cataract surgery, and each had complicated cataract surgery. Six patients who underwent vitrectomy before cataract surgery experienced intraoperative complications. Three patients in whom vitrectomy was performed after uneventful cataract surgery subsequently had delayed IOL dislocation.
Assuntos
Extração de Catarata/efeitos adversos , Catarata/complicações , Vitrectomia/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de RiscoRESUMO
BACKGROUND: We and others have previously demonstrated that the µ-opioid receptor (MOR) is overexpressed in several human malignancies. There is a seven-fold increase in MOR in cell lines of human lung cancer. In animal models, overexpression of MOR promotes tumour growth and metastasis. We, therefore, examined whether MOR expression is increased in metastatic lung cancer. METHODS: In this study, we examined the association between MOR expression and metastasis in archived biopsy samples from patients with lung cancer. Paraffin-embedded patient material was stained using MOR antibody and scored qualitatively by two independent pathologists using a four-point scale. RESULTS: In human lung cancer and normal adjacent lung samples obtained from 34 lung cancer patients, MOR expression was increased significantly in cancer samples from patients with lung cancer compared with adjacent control tissue (P=0.0242). When the samples from patients with metastatic lung cancer were separated from the cohort of the total number of patients with lung cancer, we observed an approximately two-fold increase in MOR expression (P=0.0013). CONCLUSIONS: The association between the expression of MOR and the progression of the tumour is consistent with the hypothesis of a direct effect of MOR on cancer progression.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/secundário , Neoplasias Pulmonares/metabolismo , Receptores Opioides mu/metabolismo , Idoso , Idoso de 80 Anos ou mais , Biópsia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Progressão da Doença , Feminino , Humanos , Neoplasias Pulmonares/patologia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/metabolismo , Estadiamento de NeoplasiasRESUMO
UNLABELLED: The fast analysis of relative proportions of live and dead cells can be of great value whether for comparing inactivation efficiencies of different biocidal treatments or for monitoring organisms of interest in environmental samples. We introduce here a straightforward method to determine the percentage of intact cells based on treatment of samples with the viability dye propidium monoazide (PMA). PMA selectively enters membrane-damaged cells and suppresses their PCR detection through modification of their DNA. The study was performed using Cryptosporidium parvum oocysts as a model although the principle should be applicable to other organisms. Validation was performed with defined mixtures of live and heat-killed oocysts and by exposing oocysts to a heat stress gradient. The method correctly indicated increasingly lower proportions of intact cells with increasing temperatures. When comparing the loss of membrane integrity of UV-killed (40 mJ cm(-2) ) oocysts during storage in nonsterile tap water, results suggested that integrity declines slowly (over weeks) and at a rate comparable to non-UV-exposed oocysts. For all experiments, the amplification of longer DNA sequences was found beneficial. In the UV experiment, longer amplicons revealed not only higher sensitivity in excluding membrane-damaged oocysts, but also in excluding DNA with UV-induced damage. SIGNIFICANCE AND IMPACT OF THE STUDY: Whether in the context of microbial ecology or in an industrial context, many questions in microbiology are linked to microbial viability. As cultivation of micro-organisms can be long or may not be possible, fast methods to assess the numbers of live cells are in great demand. We present here a straightforward strategy to determine the relative proportions of intact cells. The PCR-based rapid method is expected to be useful where relative information is sufficient (e.g. for comparing the effect of different antimicrobial treatments on known numbers of micro-organisms) or when the presence of PCR inhibitors does not allow absolute quantification.
Assuntos
Azidas , Cryptosporidium parvum/fisiologia , Oocistos/fisiologia , Reação em Cadeia da Polimerase/métodos , Propídio/análogos & derivados , Cryptosporidium parvum/genética , DNA de Protozoário/análise , DNA de Protozoário/genética , Temperatura Alta , Viabilidade Microbiana , Raios UltravioletaRESUMO
The SLICK haplotype (http://omia.angis.org.au/OMIA001372/9913/) in cattle confers animals with a short and sleek hair coat. Originally identified in Senepol cattle, the gene has been introduced into Holsteins. The objectives of the current study were to determine (1) whether lactating Holsteins with the slick hair phenotype have superior ability for thermoregulation compared with wild-type cows or relatives not inheriting the SLICK haplotype, and (2) whether seasonal depression in milk yield would be reduced in SLICK cows. In experiment 1, diurnal variation in vaginal temperature in the summer was monitored for cows housed in a freestall barn with fans and sprinklers. Vaginal temperatures were lower in slick-haired cows than in relatives and wild-type cows. In experiment 2, acute responses to heat stress were monitored after cows were moved to a dry lot in which the only heat abatement was shade cloth. The increases in rectal temperature and respiration rate caused by heat stress during the day were lower for slick cows than for relatives or wild-type cows. Moreover, sweating rate was higher for slick cows than for cows of the other 2 types. In experiment 3, effects of season of calving (summer vs. winter) on milk yield and composition were determined. Compared with milk yield of cows calving in winter, milk yield during the first 90 d in milk was lower for cows calving in the summer. However, this reduction was less pronounced for slick cows than for wild-type cows. In conclusion, Holsteins with slick hair have superior thermoregulatory ability compared with non-slick animals and experience a less drastic depression in milk yield during the summer.