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Although delirium is a significant clinical and public health problem, little is understood about how specific vulnerabilities underlie the severity of its presentation. Our objective was to quantify the relationship between baseline cognition and subsequent delirium severity. We prospectively investigated a population-representative sample of 1510 individuals aged ≥70 years, of whom 209 (13.6%) were hospitalized across 371 episodes (1999 person-days assessment). Baseline cognitive function was assessed using the modified Telephone Interview for Cognitive Status, supplemented by verbal fluency measures. We estimated the relationship between baseline cognition and delirium severity [Memorial Delirium Assessment Scale (MDAS)] and abnormal arousal (Observational Scale of Level of Arousal), adjusted by age, sex, frailty and illness severity. We conducted further analyses examining presentations to specific hospital settings and common precipitating aetiologies. The median time from baseline cognitive assessment to admission was 289 days (interquartile range 130 to 47 days). In admitted patients, delirium was present on at least 1 day in 45% of admission episodes. The average number of days with delirium (consecutively positive assessments) was 3.9 days. Elective admissions accounted for 88 bed days (4.4%). In emergency (but not elective) admissions, we found a non-linear U-shaped relationship between baseline global cognition and delirium severity using restricted cubic splines. Participants with baseline cognition 2 standard deviations below average (z-score = -2) had a mean MDAS score of 14 points (95% CI 10 to 19). Similarly, those with baseline cognition z-score = + 2 had a mean MDAS score of 7.9 points (95% CI 4.9 to 11). Individuals with average baseline cognition had the lowest MDAS scores. The association between baseline cognition and abnormal arousal followed a comparable pattern. C-reactive protein ≥20 mg/l and serum sodium <125 mM/l were associated with more severe delirium. Baseline cognition is a critical determinant of the severity of delirium and associated changes in arousal. Emergency admissions with lowest and highest baseline cognition who develop delirium should receive enhanced clinical attention.
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Delirio , Humanos , Delirio/epidemiología , Estudios Prospectivos , Cognición , Proyectos de InvestigaciónRESUMEN
BACKGROUND: Around 15% of adults aged over 65 live with moderate or severe frailty. Contractual requirements for management of frailty are minimal and neither incentivised nor reinforced. Previous research has shown frailty identification in primary care is ad hoc and opportunistic, but there has been little focus on the challenges of frailty management, particularly within the context of recent introduction of primary care networks and an expanding allied health professional workforce. AIM: Explore the views of primary care clinicians in England on the management of frailty. DESIGN AND SETTING: Semi-structured interviews were conducted with clinicians across England, including general practitioners (GPs), physician associates, nurse practitioners, paramedics and clinical pharmacists. Thematic analysis was facilitated through NVivo (Version 12). RESULTS: A total of 31 clinicians participated. Frailty management was viewed as complex and outside of clinical guidelines with medication optimisation highlighted as a key example. Senior clinicians, particularly experienced GPs, were more comfortable with managing risk. Relational care was important in prioritising patient wishes and autonomy, for instance to remain at home despite deteriorations in health. In settings where more formalised multidisciplinary frailty services had been established this was viewed as successful by clinicians involved. CONCLUSION: Primary care clinicians perceive frailty as best managed through trusted relationships with patients, and with support from experienced clinicians. New multidisciplinary working in primary care could enhance frailty services, but must keep continuity in mind. There is a lack of evidence or guidance for specific interventions or management approaches.
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Actitud del Personal de Salud , Anciano Frágil , Fragilidad , Entrevistas como Asunto , Atención Primaria de Salud , Investigación Cualitativa , Humanos , Fragilidad/diagnóstico , Fragilidad/terapia , Fragilidad/psicología , Inglaterra , Anciano , Masculino , Femenino , Evaluación Geriátrica/métodos , Conocimientos, Actitudes y Práctica en SaludRESUMEN
INTRODUCTION: In 2017, NHS England introduced proactive identification of frailty into the General Practitioners (GP) contract. There is currently little information as to how this policy has been operationalised by front-line clinicians, their working understanding of frailty and impact of recognition on patient care. We aimed to explore the conceptualisation and identification of frailty by multidisciplinary primary care clinicians in England. METHODS: Qualitative semi-structured interviews were conducted with primary care staff across England including GPs, physician associates, nurse practitioners, paramedics and pharmacists. Thematic analysis was facilitated through NVivo (Version 12). RESULTS: Totally, 31 clinicians participated. Frailty was seen as difficult to define, with uncertainty about its value as a medical diagnosis. Clinicians conceptualised frailty differently, dependant on job-role, experience and training. Identification of frailty was most commonly informal and opportunistic, through pattern recognition of a frailty phenotype. Some practices had embedded population screening and structured reviews. Visual assessment and continuity of care were important factors in recognition. Most clinicians were familiar with the electronic frailty index, but described poor accuracy and uncertainty as to how to interpret and use this tool. There were different perspectives amongst professional groups as to whether frailty should be more routinely identified, with concerns of capacity and feasibility in the current climate of primary care workload. CONCLUSIONS: Concepts of frailty in primary care differ. Identification is predominantly ad hoc and opportunistic. A more cohesive approach to frailty, relevant to primary care, together with better diagnostic tools and resource allocation, may encourage wider recognition.
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Fragilidad , Médicos Generales , Humanos , Fragilidad/diagnóstico , Investigación Cualitativa , Inglaterra , Atención Primaria de Salud , Actitud del Personal de SaludRESUMEN
BACKGROUND: The highest burden of hypertension is found in Sub-Saharan Africa (SSA) with a threefold greater mortality from stroke and other associated diseases. Ethnicity is known to influence the response to antihypertensives, especially in black populations living in North America and Europe. We sought to outline the impact of all commonly used pharmacological agents on both blood pressure reduction and cardiovascular morbidity and mortality in SSA. METHODS: We used similar criteria to previous large meta-analyses of blood pressure agents but restricted results to populations in SSA. Quality of evidence was assessed using a risk of bias tool. Network meta-analysis with random effects was used to compare the effects across interventions and meta-regression to explore participant heterogeneity. RESULTS: Thirty-two studies of 2860 participants were identified. Most were small studies from single, urban centres. Compared with placebo, any pharmacotherapy lowered SBP/DBP by 8.51/8.04 mmHg, and calcium channel blockers (CCBs) were the most efficacious first-line agent with 18.46/11.6 mmHg reduction. Fewer studies assessing combination therapy were available, but there was a trend towards superiority for CCBs plus ACE inhibitors or diuretics compared to other combinations. No studies examined the effect of antihypertensive therapy on morbidity or mortality outcomes. CONCLUSION: Evidence broadly supports current guidelines and provides a clear rationale for promoting CCBs as first-line agents and early initiation of combination therapy. However, there is a clear requirement for more evidence to provide a nuanced understanding of stroke and other cardiovascular disease prevention amongst diverse populations on the continent. TRIAL REGISTRATION: PROSPERO, CRD42019122490. This review was registered in January 2019.
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Antihipertensivos/uso terapéutico , Hipertensión/tratamiento farmacológico , África del Sur del Sahara , Humanos , Persona de Mediana Edad , Metaanálisis en RedRESUMEN
INTRODUCTION: Delirium is associated with a wide range of adverse patient safety outcomes, yet it remains consistently under-diagnosed. We undertook a systematic review of studies describing delirium in adult medical patients in secondary care. We investigated if changes in healthcare complexity were associated with trends in reported delirium over the last four decades. METHODS: We used identical criteria to a previous systematic review, only including studies using internationally accepted diagnostic criteria for delirium (the Diagnostic and Statistical Manual of Mental Disorders and the International Statistical Classification of Diseases). Estimates were pooled across studies using random effects meta-analysis, and we estimated temporal changes using meta-regression. We investigated publication bias with funnel plots. RESULTS: We identified 15 further studies to add to 18 studies from the original review. Overall delirium occurrence was 23% (95% CI 19-26%) (33 studies) though this varied according to diagnostic criteria used (highest in DSM-IV, lowest in DSM-5). There was no change from 1980 to 2019, nor was case-mix (average age of sample, proportion with dementia) different. Overall, risk of bias was moderate or low, though there was evidence of increasing publication bias over time. DISCUSSION: The incidence and prevalence of delirium in hospitals appears to be stable, though publication bias may have masked true changes. Nonetheless, delirium remains a challenging and urgent priority for clinical diagnosis and care pathways.
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Delirio , Pacientes Internos , Delirio/diagnóstico , Delirio/epidemiología , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Humanos , Incidencia , PrevalenciaRESUMEN
BACKGROUND: The increased risk of dementia after delirium and infection might be influenced by cerebral white matter disease (WMD). In patients with transient ischaemic attack (TIA) and minor stroke, we assessed associations between hospital admissions with delirium and 5-year dementia risk and between admissions with infection and dementia risk, stratified by WMD severity (moderate or severe vs absent or mild) on baseline brain imaging. METHODS: We included patients with TIA and minor stroke (National Institutes of Health Stroke Score <3) from the Oxford Vascular Study (OXVASC), a longitudinal population-based study of the incidence and outcomes of acute vascular events in a population of 94â567 individuals, with no age restrictions, attending eight general practices in Oxfordshire, UK. Hospitalisation data were obtained through linkage to the Oxford Cognitive Comorbidity, Frailty, and Ageing Research Database-Electronic Patient Records (ORCHARD-EPR). Brain imaging was done using CT and MRI, and WMD was prospectively graded according to the age-related white matter changes (ARWMC) scale and categorised into absent, mild, moderate, or severe WMD. Delirium and infection were defined by ICD-10 coding supplemented by hand-searching of hospital records. Dementia was diagnosed using clinical or cognitive assessment, medical records, and death certificates. Associations between hospitalisation with delirium and hospitalisation with infection, and post-event dementia were assessed using time-varying Cox analysis with multivariable adjustment, and all models were stratified by WMD severity. FINDINGS: From April 1, 2002, to March 31, 2012, 1369 individuals were prospectively recruited into the study. Of 1369 patients (655 with TIA and 714 with minor stroke, mean age 72 [SD 13] years, 674 female and 695 male, and 364 with moderate or severe WMD), 209 (15%) developed dementia. Hospitalisation during follow-up occurred in 891 (65%) patients of whom 103 (12%) had at least one delirium episode and 236 (26%) had at least one infection episode. Hospitalisation without delirium or infection did not predict subsequent dementia (HR 1·01, 95% CI 0·86-1·20). In contrast, hospitalisation with delirium predicted subsequent dementia independently of infection in patients with and without WMD (2·64, 1·47-4·74; p=0·0013 vs 3·41, 1·91-6·09; p<0·0001) especially in those with unimpaired baseline cognition (cognitive test score above cutoff; 4·01, 2·23-7·19 vs 3·94, 1·95-7·93; both p≤0·0001). However, hospitalisation with infection only predicted dementia in those with moderate or severe WMD (1·75, 1·04-2·94 vs 0·68, 0·39-1·20; pdiff=0·023). INTERPRETATION: The increased risk of dementia after delirium is unrelated to the presence of WMD, whereas infection increases risk only in patients with WMD, suggesting differences in underlying mechanisms and in potential preventive strategies. FUNDING: National Institute for Health and Care Research and Wellcome Trust.
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Delirio , Demencia , Ataque Isquémico Transitorio , Leucoencefalopatías , Accidente Cerebrovascular , Estados Unidos , Humanos , Masculino , Femenino , Anciano , Ataque Isquémico Transitorio/complicaciones , Ataque Isquémico Transitorio/diagnóstico , Ataque Isquémico Transitorio/epidemiología , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/etiología , Encéfalo/diagnóstico por imagen , Leucoencefalopatías/diagnóstico por imagen , Leucoencefalopatías/epidemiología , Leucoencefalopatías/complicaciones , Demencia/diagnóstico por imagen , Demencia/epidemiología , Demencia/etiología , Delirio/diagnóstico por imagen , Delirio/epidemiología , Delirio/etiologíaRESUMEN
Background: Urinary tract infection (UTI) affects half of women at least once in their lifetime. Current diagnosis involves urinary dipstick and urine culture, yet both methods have modest diagnostic accuracy, and cannot support decision-making in patient populations with high prevalence of asymptomatic bacteriuria, such as older adults. Detecting biomarkers of host response in the urine of hosts has the potential to improve diagnosis. Objectives: To synthesise the evidence of the diagnostic accuracy of novel biomarkers for UTI, and of their ability to differentiate UTI from asymptomatic bacteriuria. Design: A systematic review. Data Sources and Methods: We searched MEDLINE, EMBASE, CINAHL and Web of Science for studies of novel biomarkers for the diagnosis of UTI. We excluded studies assessing biomarkers included in urine dipsticks as these have been well described previously. We included studies of adult patients (≥16 years) with a suspected or confirmed urinary tract infection using microscopy and culture as the reference standard. We excluded studies using clinical signs and symptoms, or urine dipstick only as a reference standard. Quality appraisal was performed using QUADAS-2. We summarised our data using point estimates and data accuracy statistics. Results: We included 37 studies on 4009 adults measuring 66 biomarkers. Study quality was limited by case-control design and study size; only 4 included studies had a prospective cohort design. IL-6 and IL-8 were the most studied biomarkers. We found plausible evidence to suggest that IL-8, IL-6, GRO-a, sTNF-1, sTNF-2 and MCR may benefit from more rigorous evaluation of their potential diagnostic value for UTI. Conclusions: There is insufficient evidence to recommend the use of any novel biomarker for UTI diagnosis at present. Further evaluation of the more promising candidates, is needed before they can be recommended for clinical use.
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BACKGROUND: Sore throat is a common and self-limiting condition. There remains ambiguity in stratifying patients to immediate, delayed, or no antibiotic prescriptions. The National Institute for Health and Care Excellence (NICE) recommends two clinical prediction rules (CPRs), FeverPAIN and Centor, to guide decision making. AIM: To describe the diagnostic accuracy of CPRs in identifying streptococcal throat infections. DESIGN & SETTING: Adults presenting to UK primary care with sore throat, who did not require immediate antibiotics. METHOD: As part of the Treatment Options without Antibiotics for Sore Throat (TOAST) trial, 565 participants, aged ≥18 years, were recruited on day of presentation to general practice. Physicians could opt to give delayed prescriptions. CPR scores were not part of the trial protocol but were calculated post hoc from baseline assessments. Diagnostic accuracy was calculated by comparing scores with throat swab cultures. RESULTS: It was found that 81/502 (16.1%) patients had group A, C, or G streptococcus cultured on throat swab. Overall diagnostic accuracy of both CPRs was poor: area under receiver operating characteristics (ROC) curve 0.62 for Centor; and 0.59 for FeverPAIN. Post-test probability of a positive or negative test was 27.3% (95% confidence interval [CI] = 6.0% to 61.0%) and 84.1% (95% CI = 80.6% to 87.2%) for FeverPAIN ≥4; versus 25.7% (95% CI = 16.2% to 37.2%) and 85.5% (95% CI = 81.8% to 88.7%) for Centor ≥3. Higher CPR scores were associated with increased delayed antibiotic prescriptions (χ2 = 8.42, P = 0.004 for FeverPAIN ≥4; χ2 = 32.0, P<0.001 for Centor ≥3). CONCLUSION: In those who do not require immediate antibiotics in primary care, neither CPR provides a reliable way of diagnosing streptococcal throat infection. However, clinicians were more likely to give delayed prescriptions to those with higher scores.
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BACKGROUND: The aim of RApid community Point-of-care Testing fOR COVID-19 (RAPTOR-C19) is to assess the diagnostic accuracy of multiple current and emerging point-of-care tests (POCTs) for active and past SARS-CoV2 infection in the community setting. RAPTOR-C19 will provide the community testbed to the COVID-19 National DiagnOstic Research and Evaluation Platform (CONDOR). METHODS: RAPTOR-C19 incorporates a series of prospective observational parallel diagnostic accuracy studies of SARS-CoV2 POCTs against laboratory and composite reference standards in patients with suspected current or past SARS-CoV2 infection attending community settings. Adults and children with suspected current SARS-CoV2 infection who are having an oropharyngeal/nasopharyngeal (OP/NP) swab for laboratory SARS-CoV2 reverse transcriptase Digital/Real-Time Polymerase Chain Reaction (d/rRT-PCR) as part of clinical care or community-based testing will be invited to participate. Adults (≥ 16 years) with suspected past symptomatic infection will also be recruited. Asymptomatic individuals will not be eligible. At the baseline visit, all participants will be asked to submit samples for at least one candidate point-of-care test (POCT) being evaluated (index test/s) as well as an OP/NP swab for laboratory SARS-CoV2 RT-PCR performed by Public Health England (PHE) (reference standard for current infection). Adults will also be asked for a blood sample for laboratory SARS-CoV-2 antibody testing by PHE (reference standard for past infection), where feasible adults will be invited to attend a second visit at 28 days for repeat antibody testing. Additional study data (e.g. demographics, symptoms, observations, household contacts) will be captured electronically. Sensitivity, specificity, positive, and negative predictive values for each POCT will be calculated with exact 95% confidence intervals when compared to the reference standard. POCTs will also be compared to composite reference standards constructed using paired antibody test results, patient reported outcomes, linked electronic health records for outcomes related to COVID-19 such as hospitalisation or death, and other test results. DISCUSSION: High-performing POCTs for community use could be transformational. Real-time results could lead to personal and public health impacts such as reducing onward household transmission of SARS-CoV2 infection, improving surveillance of health and social care staff, contributing to accurate prevalence estimates, and understanding of SARS-CoV2 transmission dynamics in the population. In contrast, poorly performing POCTs could have negative effects, so it is necessary to undertake community-based diagnostic accuracy evaluations before rolling these out. TRIAL REGISTRATION: ISRCTN, ISRCTN14226970.
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INTRODUCTION: The epidemiology of acute kidney injury (AKI) in children in sub-Sahara Africa (SSA) is poorly described. The aim of this study was to establish the incidence, etiology, and outcomes of community-acquired AKI in pediatric admissions in Southern Malawi. METHODS: We conducted a prospective observational study of pediatric admissions to a tertiary hospital in Blantyre between 5 February and 30 April 2016. Children were screened for kidney disease on admission with measurement of serum creatinine and assessment of urine output. The clinical presentation, etiology, and management of children with AKI were documented. RESULTS: A total of 412 patients (median age 4 years, 52.6% male, and 7.5% human immunodeficiency virus [HIV] infected) were included in the study. Forty-five patients (10.9%) had AKI (Kidney Disease: Improving Global Outcomes [KDIGO] criteria), which was stage 3 in 16 (35.6%) patients. Sepsis and hypoperfusion, most commonly due to malaria (n = 19; 42.2%), were the causes of AKI in 38 cases (84.4%). Three patients (6.7%) underwent peritoneal dialysis (PD) for AKI: 2 of them recovered kidney function, and the other one died. In-hospital mortality was 20.5% in AKI and 2.9% if no kidney disease was present (p < 0.0001). Seventeen (47.2%) patients with kidney disease had persistent kidney injury on hospital discharge. CONCLUSION: Acute kidney injury occurs in 10.9% of pediatric admissions in Malawi and is primarily due to infections, particularly malaria. Acute kidney injury results in significantly increased in-hospital mortality. Urgent interventions are required to eliminate preventable causes of death in this region.
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Lesión Renal Aguda/epidemiología , Lesión Renal Aguda/terapia , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/terapia , Hospitalización/estadística & datos numéricos , Lesión Renal Aguda/etiología , Niño , Preescolar , Estudios de Cohortes , Infecciones Comunitarias Adquiridas/complicaciones , Femenino , Infecciones por VIH/complicaciones , Infecciones por VIH/diagnóstico , Infecciones por VIH/tratamiento farmacológico , Mortalidad Hospitalaria/tendencias , Humanos , Lactante , Modelos Logísticos , Malaria/complicaciones , Malaria/diagnóstico , Malaria/terapia , Malaui/epidemiología , Masculino , Análisis Multivariante , Diálisis Peritoneal/métodos , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Medición de Riesgo , Centros de Atención TerciariaRESUMEN
Thiazolyl peptides are a class of rigid macrocyclic compounds richly populated with thiazole rings. They are highly potent antibiotics but none have been advanced to clinic due to poor aqueous solubility. Recent progress in this field prompted a reinvestigation leading to the isolation of a new thiazolyl peptide, thiazomycin, a congener of nocathiacins. Thiazomycin possesses an oxazolidine ring as part of the amino-sugar moiety in contrast to the dimethyl amino group present in nocathiacin I. The presence of the oxazolidine ring provides additional opportunities for chemical modifications that are not possible with other nocathiacins. Thiazomycin is extremely potent against Gram-positive bacteria both in vitro and in vivo. The titer of thiazomycin in the fermentation broth was very low compared to the nocathiacins I and III. The lower titer together with its sandwiched order of elution presented significant challenges in large scale purification of thiazomycin. This problem was resolved by the development of an innovative preferential protonation based one- and/or two-step chromatographic method, which was used for pilot plant scale purifications of thiazomycin. The isolation and structure elucidation of thiazomycin is herein described.
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Actinomycetales/química , Antibacterianos/aislamiento & purificación , Péptidos Cíclicos/aislamiento & purificación , Tiazoles/aislamiento & purificación , Actinomycetales/clasificación , Antibacterianos/química , Cromatografía Liquida/métodos , Fermentación , Bacterias Grampositivas/efectos de los fármacos , Péptidos y Proteínas de Señalización Intercelular , Mutación , Péptidos/química , Péptidos/aislamiento & purificación , Péptidos Cíclicos/química , Solubilidad , Tiazoles/químicaRESUMEN
Facility experience primarily in drug-oriented fermentation equipment (producing small molecules such as secondary metabolites, bioconversions, and enzymes) and, to a lesser extent, in biologics-oriented fermentation equipment (producing large molecules such as recombinant proteins and microbial vaccines) in an industrial fermentation pilot plant over the past 15 years is described. Potential approaches for equipment design and maintenance, operational procedures, validation/verification testing, medium selection, culture purity/sterility analysis, and contamination investigation are presented, and those approaches implemented are identified. Failure data collected for pilot plant operation for nearly 15 years are presented and best practices for documentation and tracking are outlined. This analysis does not exhaustively discuss available design, operational and procedural options; rather it selectively presents what has been determined to be beneficial in an industrial pilot plant setting. Literature references have been incorporated to provide background and context where appropriate.
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Reactores Biológicos/microbiología , Descontaminación/métodos , Contaminación de Equipos/prevención & control , Análisis de Falla de Equipo/métodos , Fermentación , Microbiología Industrial/instrumentación , Mantenimiento/métodos , Descontaminación/instrumentación , Análisis de Falla de Equipo/instrumentación , Microbiología Industrial/métodos , Proyectos PilotoAsunto(s)
Atención Ambulatoria/métodos , Infecciones por VIH/inmunología , Subgrupos de Linfocitos T/inmunología , Adulto , Atención Ambulatoria/normas , Recuento de Linfocito CD4/normas , Femenino , Citometría de Flujo/normas , Humanos , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Factores de TiempoRESUMEN
The uptake of stereotactic ablative body radiation therapy (SABR)/stereotactic body radiation therapy (SBRT) worldwide has been rapid. The Australian and New Zealand Faculty of Radiation Oncology (FRO) assembled an expert panel of radiation oncologists, radiation oncology medical physicists and radiation therapists to establish guidelines for safe practice of SABR. Draft guidelines were reviewed by a number of international experts in the field and then distributed through the membership of the FRO. Members of the Australian Institute of Radiography and the Australasian College of Physical Scientists and Engineers in Medicine were also asked to comment on the draft. Evidence-based recommendations (where applicable) address aspects of departmental staffing, procedures and equipment, quality assurance measures, as well as organisational considerations for delivery of SABR treatments. Central to the guidelines is a set of key recommendations for departments undertaking SABR. These guidelines were developed collaboratively to provide an educational guide and reference for radiation therapy service providers to ensure appropriate care of patients receiving SABR.
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Oncología Médica/normas , Seguridad del Paciente/normas , Guías de Práctica Clínica como Asunto , Monitoreo de Radiación/normas , Protección Radiológica/normas , Radiocirugia/normas , Australia , Nueva ZelandaRESUMEN
A defined medium and fed-batch feeding process for the production of a yeast biocatalyst, developed at the 23-L scale, was scaled up to the 600-L pilot scale. Presterilized 100-L-vol plastic bags were implemented for the pilot-scale nutrient feeding. Medium of increased concentration Oqs implemented at the pilot scale, and equivalent dry cell weights were reached with a medium 80% more concentrated than that used at the laboratory scale. The higher medium concentration was believed to be necessary at the pilot scale owing to the additional heat stresses on key components (e.g., complexing of magnesium sulfate with phosphate), increased dilution during sterilization, lower evaporation rate owing to the lower vessel volume per minute air flow rate, and increased dilution owing to nutrient feeding or shot additions. Peak cell density was found to be somewhat insensitive to variations in residual glucose levels. These results suggest that defined medium developed at the laboratory scale may need to be further optimized at the pilot scale for equivalent performance.
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Biotecnología/métodos , Candida/metabolismo , Medios de Cultivo , Glucosa/farmacología , Dextranos/metabolismo , Glucosa/metabolismo , Factores de TiempoRESUMEN
BACKGROUND: Nontyphoidal Salmonellae frequently cause life-threatening bacteremia in sub-Saharan Africa. Young children and HIV-infected adults are particularly susceptible. High case-fatality rates and increasing antibiotic resistance require new approaches to the management of this disease. Impaired cellular immunity caused by defects in the T helper 1 pathway lead to intracellular disease with Salmonella that can be countered by IFNγ administration. This report identifies the lymphocyte subsets that produce IFNγ early in Salmonella infection. METHODOLOGY: Intracellular cytokine staining was used to identify IFNγ production in blood lymphocyte subsets of ten healthy adults with antibodies to Salmonella (as evidence of immunity to Salmonella), in response to stimulation with live and heat-killed preparations of the D23580 invasive African isolate of Salmonella Typhimurium. The absolute number of IFNγ-producing cells in innate, innate-like and adaptive lymphocyte subpopulations was determined. PRINCIPAL FINDINGS: Early IFNγ production was found in the innate/innate-like lymphocyte subsets: γδ-T cells, NK cells and NK-like T cells. Significantly higher percentages of such cells produced IFNγ compared to adaptive αß-T cells (Student's t test, P<0.001 and ≤0.02 for each innate subset compared, respectively, with CD4(+)- and CD8(+)-T cells). The absolute numbers of IFNγ-producing cells showed similar differences. The proportion of IFNγ-producing γδ-T cells, but not other lymphocytes, was significantly higher when stimulated with live compared with heat-killed bacteria (P<0.0001). CONCLUSION/SIGNIFICANCE: Our findings indicate an inherent capacity of innate/innate-like lymphocyte subsets to produce IFNγ early in the response to Salmonella infection. This may serve to control intracellular infection and reduce the threat of extracellular spread of disease with bacteremia which becomes life-threatening in the absence of protective antibody. These innate cells may also help mitigate against the effect on IFNγ production of depletion of Salmonella-specific CD4(+)-T lymphocytes in HIV infection.