Genomic characterization of a multidrug-resistant uropathogenic Escherichia coli and evaluation of Echeveria plant extracts as antibacterials.

Uropathogenic Escherichia coli (UPEC) is the most common bacterial agent associated with urinary tract infections, threatening public health systems with elevated medical costs and high morbidity rates. The successful establishment of the infection is associated with virulence factors encoded in its genome, in addition to antibacterial resistance genes, which could limit the treatment and resolution of the infection. In this sense, plant extracts from the genus Echeveria have traditionally been used to treat diverse infectious diseases. However, little is known about the effects of these extracts on bacteria and their potential mechanisms of action. This study aims to sequence a multidrug-resistant UPEC isolate (UTI-U7) and assess the multilocus sequence typing (MLST), virulence factors, antimicrobial resistance profile, genes, serotype, and plasmid content. Antimicrobial susceptibility profiling was performed using the Kirby-Bauer disk diffusion. The antibacterial and anti-adherent effects of the methanol extracts (ME) of Echeveria (E. craigiana, E. kimnachii, and E. subrigida) against UTI-U7 were determined. The isolate was characterized as an O25:H4-B2-ST2279-CH40 subclone and had resistant determinants to aminoglycosides, ß-lactams, fluoroquinolones/quinolones, amphenicols, and tetracyclines, which matched with the antimicrobial resistance profile. The virulence genes identified encode adherence factors, iron uptake, protectins/serum resistance, and toxins. Identified plasmids belonged to the IncF group (IncFIA, IncFIB, and IncFII), alongside several prophage-like elements. After an extensive genome analysis that confirmed the pathogenic status of UTI-U7 isolate, Echeveria extracts were tested to determine their antibacterial effects; as an extract, E. subrigida (MIC, 5 mg/mL) displayed the best inhibitory effect. However, the adherence between UTI-U7 and HeLa cells was unaffected by the ME of the E. subrigida extract.

Clinical Efficacy of SARS-CoV-2 Vaccination in Hemodialysis Patients.

Introduction: The COVID-19 pandemic is a global public health problem. Patients with end-stage renal disease on hemodialysis are at a higher risk of infection and mortality than the general population. Worldwide, a vaccination campaign has been developed that has been shown to reduce severe infections and deaths in the general population. However, there are currently limited data on the clinical efficacy of vaccinations in the hemodialysis population. Methods: A national multicenter observational cohort was performed in Chile to evaluate the clinical efficacy of anti-SARS-CoV-2 vaccination in end-stage renal disease patients on chronic hemodialysis from February 2021 to August 2021. In addition, the BNT162b2 (Pfizer-BioNTech) and CoronaVac (Sinovac) vaccines were evaluated. The efficacy of vaccination in preventing SARS-CoV-2 infection, hospitalizations, and deaths associated with COVID-19 was determined. Results: A total of 12,301 patients were evaluated; 10,615 (86.3%) received a complete vaccination (2 doses), 490 (4.0%) received incomplete vaccination, and 1196 (9.7%) were not vaccinated. During follow-up, 1362 (11.0%) patients developed COVID-19, and 150 died (case fatality rate: 11.0%). The efficacy of the complete vaccination in preventing infection was 18.1% (95% confidence interval [CI]:11.8-23.8%), and prevention of death was 66.0% (95% CI:60.6-70.7%). When comparing both vaccines, BNT162b2 and CoronaVac were effective in reducing infection and deaths associated with COVID-19. Nevertheless, the BNT162b2 vaccine had higher efficacy in preventing infection (42.6% vs. 15.0%) and deaths (90.4% vs. 64.8%) compared to CoronaVac. Conclusion: The results of our study suggest that vaccination against SARS-CoV-2 in patients on chronic hemodialysis was effective in preventing infection and death associated with COVID-19.

Survival study and factors associated with mortality in Chilean patients on peritoneal dialysis infected with SARS-CoV-2.

The Covid-19 pandemic has been responsible for millions of deaths worldwide. Patients with comorbidities- such as those on peritoneal dialysis (PD)- present higher morbidity and mortality than the general population. We prospectively evaluated all Chilean patients on PD (48 centres) and followed those who had Covid-19 from the beginning of the Covid-19 pandemic in Chile (March 2020) to January 2021 (start of vaccination campaign). We described demographic history, comorbidities, factors related to infection, need for hospitalisation and death due to Covid-19. During the study period, 106 adults on PD were infected by SARS-CoV-2, with a mean age of 53.1 (±16.3) and of which 53.9% were female. From that group, 54.8% required hospitalisation and 24.5% (n = 26) died due to Covid-19. Most of the patients (63.4%) were infected at home and 22.8% during hospitalisation for other reasons. There was a significant association for Covid-19 mortality with: being ≥60 years old, diabetes, time on PD ≥5 years, need for hospitalisation and hospital-acquired infection. At 90 days of follow-up, all deaths associated to Covid-19 occurred before 40 days. We conclude that patients on PD without Covid-19 vaccination have a high mortality and need for hospitalisation associated to Covid-19. To avoid this negative outcome, it is necessary to intensify strategies to avoid contagion, especially in those ≥60 years old, with diabetes and/or ≥5 years spent on PD.

Analysis of Multi-Pesticide Residues and Dietary Risk Assessment in Fresh Tomatoes (Lycopersicum esculentum) from Local Supermarkets of the Metropolitan Region, Chile.

In recent years, the official authorities in Chile have reported transgressions in the maximum residue levels of pesticides in fresh vegetables. There is no official information about traceability, pesticide levels, and potential health risks. The aim of this study was to analyse pesticide residues and their corresponding dietary risk assessments in tomatoes from supermarkets in the Metropolitan Region. Pesticides were extracted using the Quick, Easy, Cheap, Effective, Rugged and Safe, QuEChERS method, and their concentrations were determined by using chromatography with HPLC-FL/UV and GC-MS/ECD/NPD, following the Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in Food and Feed, SANTE guide and ISO 17025:2017 standard. In addition, a dietary risk assessment was carried out by comparing Chilean data to international references. The results reported that 9% of the samples had pesticide residue levels above the maximum residue levels permitted in Chile. All the scenarios evaluated revealed the highest estimated daily intake and hazard quotients for methamidophos and chlorpyrifos. Both the active substances used were acetylcholinesterase inhibitors and were neurotoxic under chronic risk assessment. The results showed the highest chronic hazard index in the Chilean scenario for all age groups and genders. The evidence obtained revealed that methamidophos, methomyl, and chlorpyrifos should be restricted for their use in Chilean agriculture.

Carbapenemasas en Pseudomonas aeruginosa con susceptibilidad disminuida a los carbapenémicos después de una década, desde VIM a KPC / Carbapenemases in Pseudomonas aeruginosa with decreased susceptibility to carbapenems after a decade: from VIM to KPC

Resumen Introducción: Pseudomonas aeruginosa es relevante en infecciones asociadas a la atención de salud, principalmente cuando presenta resistencia a carbapenémicos. Objetivos: Estudiar la producción de carbapenemasas en P. aeruginosa, con susceptibilidad disminuida a carbapenémicos procesadas en el Laboratorio de Microbiología de la Red de Salud UC-CHRISTUS entre 2014-2015, y compararlas con las cepas estudiadas en 2004-2005. Métodos: Entre enero de 2014 y junio de 2015, se aislaron 459 cepas de P. aeruginosa provenientes de muestras clínicas. La susceptibilidad fue determinada por dilución en agar y a las cepas con susceptibilidad disminuida a carbapenémicos se les realizó test de carbaNP. Las cepas positivas fueron estudiadas por RPC para genes blaVIM, blaVIM-1, blaVIM-2, blaIMP, blaNDM, blaKPC, blaOXA y blaIMI. Se realizó en cepas seleccionadas electroforesis de campo pulsado. Resultados: De las 459 cepas estudiadas, 300 presentaban susceptibilidad disminuida a carbapenémicos (65,3%). De éstas, 183 fueron viables para estudio, correspondientes a 164 pacientes. El test de carbaNP fue positivo en 44 cepas de las 183 cepas (24%). Los genes de resistencia encontrados fueron: blaVIM-2 en 35 cepas, blaKPC-2+VIM-2 en 7 cepas y blaKPC-2 en 2 cepas. En las cepas blaKPC-2 se encontró relación clonal entre ellas. Conclusiones: Un 65,3% de P. aeruginosa presentó susceptibilidad disminuida a carbapenémicos, observándose que la presencia de carbapenemasas no es el principal mecanismo de resistencia. Además, se describe la emergencia en Chile de cepas de P. aeruginosa con carbapenemasas del tipo KPC-2 sola o en combinación con VIM-2.

Abstract Background: Pseudomonas aeruginosa is a relevant infectious agent affecting patients within health care setting; this situation is worsening with the appearance of strains resistance to carbapenems. Aims: To study carbapenemase production in P. aeruginosa with decreased susceptibility to carbapenems processed in the microbiology laboratory of the Health Network UC-CHRISTUS in 2014-2015 and compare them with the strains studied in 2004-2005. Methods: Between January 2014 and June 2015, 459 strains of P. aeruginosa from clinical samples were isolated. Susceptibility was determined by dilution in agar and strains with reduced susceptibility to carbapenems were tested for carbaNP. Positive strains were studied by PCR for blaVIM, blaVIM-1, blaVIM-2, blaIMP, blaNDM, blaKPC, blaOXA and blaIMI genes. Pulsed field electrophoresis was performed on selected strains. Results: From 459 strains studied, 300 had reduced susceptibility to carbapenems (65.3%). Of these, 183 were viable for study, corresponding to 164 patients. The carbaNP test was positive in 44 strains of the 183 strains (24%). The resistance genes found were: blaVIM-2 in 35 strains, blaKPC-2+VIM-2 in 7 strains and blaKPC-2 in 2 strains. In the blaKPC-2 strains clonal relation between them was found. Conclusions: A 65.3% of P. aeruginosa presented decreased susceptibility to carbapenems being the presence of carbapenemases not the main resistance mechanism. In addition, the emergence in Chile of P. aeruginosa strains with bla of the KPC-2 type alone or in combination with VIM-2 is described.

Pesticide Residues and Health Risk Assessment in Tomatoes and Lettuces from Farms of Metropolitan Region Chile.

Over the last years, the detection of pesticide residues in the official food surveillance programs of Chile has been increased, mainly in fresh vegetables such as tomatoes and lettuces. The Metropolitana Region of Chile presents the highest detections in the country. The lack of evaluations of toxicological risks in human health have increased uncertainty of the potential effects of pesticides exposures in the Chilean population. This research aims to determinate health risks assessment of pesticide residues associated to tomatoes and lettuces produced in Metropolitana Region. The findings of this study reveal that tomatoes and lettuces cultivated in the MR show more than 50% of samples with one or multiple pesticides residues. From the total samples, 16% were over the Chilean Maximum Residue Levels (MRLs). The main pesticides detected in tomatoes and lettuces were methamidophos, methomyl, difenoconazole, cyprodinil and boscalid. The results obtained using the official data of the Ministry of Health of Chile (MINSAL) compared to the World Health Organization (WHO), describe relevant risks through the Estimated Daily Intakes (EDI), Hazard Quotients (HQ) and Hazard Index (HI) for the Chilean population due to high concentrations of methamidophos, methomyl and cyprodinil. More restrictions for the use of methamidophos, methomyl, difenoconazole, cyprodinil and boscalid and effective control programs should be implemented in order to mitigate the impacts on the Chilean population.

[Carbapenemases in Pseudomonas aeruginosa with decreased susceptibility to carbapenems after a decade: from VIM to KPC]. / Carbapenemasas en Pseudomonas aeruginosa con susceptibilidad disminuida a los carbapenémicos después de una década, desde VIM a KPC.

BACKGROUND: Pseudomonas aeruginosa is a relevant infectious agent affecting patients within health care setting; this situation is worsening with the appearance of strains resistance to carbapenems. AIMS: To study carbapenemase production in P. aeruginosa with decreased susceptibility to carbapenems processed in the microbiology laboratory of the Health Network UC-CHRISTUS in 2014-2015 and compare them with the strains studied in 2004-2005. METHODS: Between January 2014 and June 2015, 459 strains of P. aeruginosa from clinical samples were isolated. Susceptibility was determined by dilution in agar and strains with reduced susceptibility to carbapenems were tested for carbaNP. Positive strains were studied by PCR for blaVIM, blaVIM-1, blaVIM-2, blaIMP, blaNDM, blaKPC, blaOXA and blaIMI genes. Pulsed field electrophoresis was performed on selected strains. RESULTS: From 459 strains studied, 300 had reduced susceptibility to carbapenems (65.3%). Of these, 183 were viable for study, corresponding to 164 patients. The carbaNP test was positive in 44 strains of the 183 strains (24%). The resistance genes found were: blaVIM-2 in 35 strains, blaKPC-2+VIM-2 in 7 strains and blaKPC-2 in 2 strains. In the blaKPC-2 strains clonal relation between them was found. CONCLUSIONS: A 65.3% of P. aeruginosa presented decreased susceptibility to carbapenems being the presence of carbapenemases not the main resistance mechanism. In addition, the emergence in Chile of P. aeruginosa strains with bla of the KPC-2 type alone or in combination with VIM-2 is described.

Pesticide residues in ready-to-eat leafy vegetables from markets of Santiago, Chile, and consumer's risk.

The detection of pesticide residues in leafy vegetables has been a relevant concern in Chile over the last years. There is also a priority at the national level to propose a methodology to assess health risks. The aim of this study was to evaluate the presence of pesticide residues in ready-to-eat leafy vegetables in order to evaluate different models for health risk assessment. The models considered data of the World Health Organization (WHO) and the Ministry of Health of Chile (MINSAL). The Hazard Quotients and Hazard Indexes for the pesticides evaluated in all models decreased in the following order: methamidophos>lambda-cyhalothrin> chlorpyrifos. From a food safety perspective, the investigated samples suggest the presence of a greater health risk to consumers when compared using the official data of MINSAL, which needs appropriate attention.

Expression of the sRNAs CrcZ and CrcY modulate the strength of carbon catabolite repression under diazotrophic or non-diazotrophic growing conditions in Azotobacter vinelandii.

Azotobacter vinelandii is a nitrogen-fixing bacterium of the Pseudomonadaceae family that prefers the use of organic acids rather than carbohydrates. Thus, in a mixture of acetate-glucose, glucose is consumed only after acetate is exhausted. In a previous work, we investigated the molecular basis of this carbon catabolite repression (CCR) process under diazotrophic conditions. In the presence of acetate, Crc-Hfq inhibited translation of the gluP mRNA, encoding the glucose transporter in A. vinelandii. Herein, we investigated the regulation in the expression of the small non-coding RNAs (sRNAs) crcZ and crcY, which are known to antagonize the repressing activity of Hfq-Crc. Our results indicated higher expression levels of the sRNAs crcZ and crcY under low CCR conditions (i.e. glucose), in relation to the strong one (acetate one). In addition, we also explored the process of CCR in the presence of ammonium. Our results revealed that CCR also occurs under non-diazotrophic conditions as we detected a hierarchy in the utilization of the supplied carbon sources, which was consistent with the higher expression level of the crcZ/Y sRNAs during glucose catabolism. Analysis of the promoters driving transcription of crcZ and crcY confirmed that they were RpoN-dependent but we also detected a processed form of CrcZ (CrcZ*) in the RpoN-deficient strain derived from a cbrB-crcZ co-transcript. CrcZ* was functional and sufficient to allow the assimilation of acetate.

[Hemobilia secondary to hepatic artery pseudoaneurysm]. / Hemobilia secundaria a pseudoaneurisma de la arteria hepática.

Hemobilia is defined as the presence of blood in the biliary tree characterized by the triad: jaundice, right hypochondrium pain (RH) and upper gastrointestinal bleeding (UGB). Among the etiologies highlighted in order of frequency there are: liver trauma (accidental and iatrogenic), inflammatory causes (acute and chronic cholecystitis), infections (cholangitis, liver abscesses, parasitic infections) and vascular diseases (aneurysms, vasculitis, arteriovenous malformations). There exist many complementary tests for the diagnosis of hemobilia, such as imaging (abdominal ultrasound, CT scan, angio CT), videoendoscopy, endoscopic retrograde cholangiopancreatography and angiography, the latter being considered the diagnostic tool and therapeutic modality of choice. We report the case of a 52-year-old male patient with hemobilia secondary to apseudoaneurysm ofthe hepatic artery, along with a review of the existing literature.

[Diagnostic accuracy study comparing total alkaline phosphatase with intact parathyroid hormone 1-84 for the diagnosis of high turnover renal osteodystrophy in chronic renal failure on hemodialysis]. / Estudio de exactitud diagnóstica que compara fosfatasa alcalina total con paratohormona intacta 1-84 para el diagnóstico de osteodistrofia renal de alto recambio en la insuficiencia renal crónica en hemodiálisis.

INTRODUCTION: High turnover renal osteodystrophy (HTRO) is a highly prevalent complication in patients with chronic kidney disease and mineral bone disease (CKD-MBD), causing pain and significant fracture-associated morbidity and mortality. The diagnostic gold standard test is bone biopsy but there are other, more widely available screening tests such as 1-84 intact parathormone (1-84 iPTH) and nonspecific markers such as total alkaline phosphatase (tALP). PURPOSE: To determine the diagnostic value (ROC curve, predictive values and likelihood ratios) of 1-84 iPTH and tALP for HTRO screening. METHODS: A diagnostic accuracy study was performed on a sample of CKD-MDB patients, grouping them according to bone biopsy results and analyzing the results of the diagnostic tests as descriptive variables. RESULTS: The study group comprised 188 patients with CKD-MDB, 36 of which had biopsy-confirmed HTRO (19.15%). The average age was 50.2 years in the biopsy group, and 53.4 years in the non-biopsy group (p=0.2385), most were male (63.8%) and diabetic (80.5%). The mean time in dialysis was 5.02 years in the biopsy group, and 2.61 years for the non-biopsy group (p<0.001). The mean Kt/V was 1.44 in the biopsy group, and 1.40 in the non-biopsy group (p=0.5354). The mean tALP was 398.02 IU/L in the group with HTRO versus 141.76 IU/L in the group without HTRO (p<0.001). The best cut-off value for tALP was 300-350 IU/L with a near 80% post-test probability, but also with a 15-20% probability for HTRO if the test is negative. The mean 1-84 iPTH was 1248.01 pg/ml in the group with HTRO versus 350.76 pg/ml in the group without HTRO (p<0.001). The 1-84 iPTH cut-off reference value of 300 pg/ml was associated with a post-test probability of 30% for HTRO diagnosis and had a lower overall performance. The best cut-off value for iPTH 1-84 was 600 pg/ml with a post-test probability for HTRO of 70% if positive and less than 5% if the test results are negative. DISCUSSION: Both markers show good correlation with bone biopsy findings. tALP elevation detects presence of HTRO in selected patients but does not rule it out. tALP does not perform as well as 1-84 iPTH as a screening test for HTRO.

INTRODUCCIÓN: La osteodistrofia renal de alto recambio es una complicación altamente prevalente en pacientes con insuficiencia renal crónica y desorden mineral óseo, determinando dolor importante y morbimortalidad importante asociada a fracturas. El gold estándar para su diagnóstico es mediante biopsia ósea. Sin embargo, su pesquisa es mediante la elevación de paratohormona intacta 1-84 (iPTH 1-84) y otros marcadores más inespecíficos como fosfatasa alcalina total (FAT). OBJETIVOS: Determinar las propiedades diagnósticas (curva ROC, valores predictivos y likelihood ratios) de paratohormona intacta 1-84 y fosfatasa alcalina total para la sospecha de osteodistrofia renal de alto recambio. MÉTODOS: Estudio de exactitud diagnóstica tomando muestra de pacientes con insuficiencia renal crónica y desorden mineral óseo, clasificándolos según resultado de biopsia ósea y evaluando resultados de test diagnóstico señalados así como variables descriptivas de interés. RESULTADOS: De los 188 pacientes con insuficiencia renal crónica y desorden mineral óseo, 36 presentaron osteodistrofia renal de alto recambio confirmada por biopsia (19,15%). La edad promedio fue de 50,2 años en el grupo con biopsia y 53,4 en el grupo sin biopsia (p=0,2385); la mayoría fueron hombres (63,8%) y diabéticos 80,5%. El tiempo promedio en diálisis fue de 5,02 años para el grupo con biopsia y 2,61 para el grupo sin biopsia (p<0,001). Kt/V promedio 1,44 en el grupo con biopsia y 1, 40 en el grupo sin biopsia (p=0,5354). Fosfatasa alcalina total promedio 398,02 UI/L en grupo con osteodistrofia renal de alto recambio versus 141,76 UI/L en grupo sin osteodistrofia renal de alto recambio (p<0,001). El mejor valor de corte para fosfatasa alcalina total fue de ≥ 300 - 350 UI/L, determinando probabilidad post test de osteodistrofia renal de alto recambio cercana a 80% con test positivo y de 15 a 20% en caso de resultado negativo. La paratohormona intacta 1-84 promedio fue 1248,01 pg/ml en grupo con osteodistrofia renal de alto recambio versus 350,76 pg/ml en grupo sin osteodistrofia renal de alto recambio (p<0,001). El valor de corte de referencia para paratohormona intacta 1-84 ≥ 300 pg/ml se asoció a una probabilidad post test de osteodistrofia renal de alto recambio de 30% y mal rendimiento en general. El mejor valor de corte fue de ≥ 600 pg/ml con probabilidad post test de osteodistrofia renal de alto recambio del 70% con test positivo y menor a 5% con test negativo. CONCLUSIONES: Ambos marcadores estudiados muestran correlación con los hallazgos de biopsias óseas. La elevación de fosfatasa alcalina total detecta presencia de osteodistrofia renal de alto recambio en pacientes seleccionados, pero no la descarta. En rendimiento es inferior a la paratohormona intacta 1-84 como test de tamizaje.

Accuracy of diffusion-weighted imaging in the diagnosis of stroke in patients with suspected cerebral infarct.

BACKGROUND AND PURPOSE: The accuracy of diffusion-weighted imaging (DWI) for the diagnosis of acute cerebral ischemia among patients with suspected ischemic stroke arriving to an emergency room has not been studied in depth. METHODS: DWI was performed in 712 patients with acute or subacute focal symptoms that suggested an acute ischemic stroke (AIS), 609 of them with AIS. RESULTS: DWI demonstrated a sensitivity of 90% and specificity of 97%, a positive likelihood ratio of 31 and a negative likelihood ratio of 0.1 for detecting AIS. The overall accuracy was 95%. Of those patients who demonstrated abnormal DWI studies, 99.5% were AIS patients, and of those patients with normal DWI studies 63% were stroke mimics. CONCLUSIONS: DWI is accurate in detecting AIS in unselected patients with suspected AIS; a negative study should alert for nonischemic conditions.

Early steroid withdrawal in pediatric renal transplant: five years of follow-up.

This prospective, comparative trial investigated the impact on mean change in height standard deviation score (SDS), acute rejection rate, and renal function of early steroid withdrawal in 96 recipients with 5 years of follow-up. Recipients under basiliximab induction and steroid withdrawal (SW: TAC/MMF; n = 55) were compared with a matched steroid control group (SC: TAC/MMF/STEROID, n = 41). SW received steroids until Day 6, SC decreased to 10 mg/m(2) within 2 months post-transplant. Five years after SW, the longitudinal growth (SDS) gain was 1.4 ± 0.4 vs. 1.1 ± 0.3 for SC group (p < 0.02). Height benefits in prepubertal and pubertal status in both groups were demonstrated in the delta growth trends (mixed model; p < 0.01). Biopsy-proven acute rejection in SW was 11% and 17.5%, SC (p: ns). Mean eGFR (ml/min/1.73 m(2)) at 5 years post-transplant was SW 80.6 ± 27.8 vs. 82.6 ± 25.1 for SC (p: ns). The death-censored graft survival rate at 1 and 5 years was 99 and 90% for SW; 98 and 96% for SC (p = ns). PTLD incidence in SW 3.3 vs. 2.5% in SC (p: ns). Five years post-transplant, early steroid withdrawal showed positive impacts on growth, stable renal function without increased acute rejection risk, and PTLD incidence.

[Validation of transcranial Doppler in the diagnosis of brain death]. / Validez del Doppler transcraneal en el diagnóstico de muerte encefálica.

BACKGROUND: The clinical diagnosis of brain death is complex. AIM: To evaluate the diagnostic accuracy of transcranial Doppler (TCD) for brain death. PATIENTS AND METHODS: Patients seen on the intensive care unit of a private hospital between January 2004 to December 2008, were included if they were in structural coma, had no craniectomy and had a blind evaluation by a neurologist and TCD done in less than three hours. The diagnosis of brain death was based on a clinical evaluation that considered the absence of sedative drugs, median blood pressure>60 mmHg, body temperature over 35 masculine Celsius and complete absence of brainstem reflexes. An expert neurosonologist, with a TCD-PMD-100, 2 Mhz transducer, used an institutional protocol that considers the examination as positive for brain circulatory arrest when there is presence of reverberating, small systolic peaks or the disappearance of a previous signal present on both middle cerebral arteries and intracranial vertebral arteries. RESULTS: Fifty three patients were evaluated, 25 with clinical brain death. On 45 cases (84.9%), the interval between both evaluations was less than one hour. The sensitivity, specificity, positive and negative predictive values for the diagnosis of brain death with TCD were 100, 96, 96.1 and 100% respectively. Positive and negative likelihood ratios for brain death were 28 and 0, respectively. CONCLUSIONS: TCD is a valid and useful technique for the diagnosis of brain death and can be used on complicated cases.

Validez del Doppler transcraneal en el diagnóstico de muerte encefálica / Validation of transcranial Doppler in the diagnosis of brain death

Background: The clinical diagnosis of brain death is complex. Aim: To evaluate the diagnostic accuracy of transcranial Doppler (TCD) for brain death. Patients and Methods: Patients seen on the intensive care unit of a private hospital between January 2004 to December 2008, were included if they were in structural coma, had no craniectomy and had a blind evaluation by a neurologist and TCD done in less than three hours. The diagnosis of brain death was based on a clinical evaluation that considered the absence of sedative drugs, median blood pressure >60 mmHg, body temperature over 35º Celsius and complete absence of brainstem refexes. An expert neurosonologist, with a TCD-PMD-100, 2 Mhz transducer, used an institutional protocol that considers the examination as positive for brain circulatory arrest when there is presence of reverberating, small systolic peaks or the disappearance of a previous signal present on both middle cerebral arteries and intracranial vertebral arteries. Results: Fifty three patients were evaluated, 25 with clinical brain death. On 45 cases (84.9 percent), the interval between both evaluations was less than one hour. The sensitivity, specifcity, positive and negative predictive values for the diagnosis of brain death with TCD were 100, 96, 96.1 and 100 percent respectively. Positive and negative likelihood ratios for brain death were 28 and 0, respectively. Conclusions: TCD is a valid and useful technique for the diagnosis of brain death and can be used on complicated cases.

Accuracy of transcranial Doppler compared with CT angiography in diagnosing arterial obstructions in acute ischemic strokes.

BACKGROUND AND PURPOSE: Patients with acute ischemic stroke and intracranial arterial obstructions have a poor prognosis and a high probability of deteriorating at 24 hours. We aimed to evaluate the diagnostic accuracy of power motion mode Doppler (PMD-TCD) compared with CT angiography as standard in diagnosing intracranial arterial obstructions in patients presenting with ischemic stroke of <24 hours. METHODS: Consecutive patients presenting with acute ischemic stroke to the emergency department underwent high-resolution brain CT angiography and PMD-TCD within a 6-hour difference. RESULTS: A total of 100 patients were included. PMD-TCD demonstrated 34 intracranial occlusions and CTA 33. There were 6 false-positives and 4 false-negative diagnoses with PMD-TCD. PMD-TCD had a positive likelihood ratio of 13.7, a negative likelihood ratio of 0.19, sensitivity of 81.8%, and specificity of 94% for detecting an arterial occlusion in any specific artery. Results for the middle cerebral artery were: positive likelihood ratio 24.6, negative likelihood ratio 0.045, sensitivity 95.6%, and specificity 96.2%. For the anterior circulation, the results were: positive likelihood ratio 18.5, negative likelihood ratio 0, sensitivity 100%, and specificity 94.5%. For the posterior circulation, the results were: positive likelihood ratio >1000, negative likelihood ratio 0.42, sensitivity 57.1%, and specificity 100%. The post-test probability for any occluded artery when PMD-TCD was positive increased for any admission National Institutes of Health Stroke Scale score but was especially remarkable for National Institutes of Health Stroke Scale scores between 7 and 15 points. CONCLUSIONS: PMD-TCD is valid compared with CT angiography for the diagnosis of arterial occlusions in patients with acute ischemic stroke, especially in middle cerebral artery obstructions.

Chronic pancreatitis and systemic lupus erythematosus: an uncommon association.

The association between systemic lupus erythematosus (SLE) and chronic pancreatitis (CP) is extremely rare. Up to now, only six cases have been reported. We report the case of a young woman who presented her first episode of abdominal pain and hyperamylasemia at the onset of SLE and developed chronic calcifying pancreatitis after a two year period.

Early steroid withdrawal in pediatric renal transplant on newer immunosuppressive drugs.

Steroids have been a cornerstone in renal transplant immunosuppression. New immunosuppressive drugs have led to protocols using early steroid withdrawal or complete avoidance. A prospective protocol in 23 pediatric renal transplant (ages 2-14 yr) who received decreasing steroid doses stopping at day 7 post-Tx, FK, and MMF were compared with a CsA, AZT, historically matched steroid-based control group. Basiliximab was used in two doses. Anthropometric, biochemical variables, AR rates, and CMV infection were evaluated and compared using Student's t-test and regression analysis. A better growth pattern was seen in steroid withdrawal group. GFR rate and serum glucose were similar in both groups. Total serum cholesterol levels were significantly lower in steroid withdrawal group. The incidence of AR at 12 months was 4.3% in steroid withdrawal group vs. 8.6% in steroid-based group (p = ns). No difference in CMV infection was observed. Hemoglobin levels were low during the first months in both groups; reached normal values after six months. SBP became higher at 12 months in steroid-based group. Patient and graft survival was 98% in both groups at one-yr post-transplant. Early steroid withdrawal was efficacious, safe, and did not increase risk of rejection, preserving optimal growth, renal function, and reducing cardiovascular risk factors.

Peritoneal dialysis in chronic renal failure patients over 65 years of age.

The number of patients over 65 years of age with chronic renal failure has increased. Peritoneal dialysis (PD) is an effective mode of treatment for such patients. In the present study, we report our experience with automated PD in patients over 65. We recorded the demographic and clinical characteristics of the patients and the exit-site infection rate, the peritonitis rate, and the mortality rate, comparing those parameters with the same parameters in patients under 65. We followed 36 patients (30% of the total study population) who were over 65 years of age (mean: 74.5 +/- 7.3 years). Of the 36 patients, 34 (94.4%) had another chronic disease--arterial hypertension and heart disease being the more common. Eleven of the patients (31%) had diabetes. Duration of PD therapy in the group was 31.5 +/- 20.7 months. Ten of the patients (27.8%) had at least 1 catheter-related complication, including exit-site infection (n = 3), tunnel infection (n = 1), or a noninfectious complication (n = 6). The rate of catheter-related infection was 0.22 episodes/patient-year. Two catheter were lost: 1 in a case of hematoma, and 1 in a case of catheter obstruction. The rate of peritonitis was 0.16 episodes/patient-year, and the most common infectious agent was methicillin-susceptible Staphylococcus aureus. Actuarial survival of our elderly patients was 51.8% at 4 years of follow-up as compared with 81.7% in the younger patients (p = 0.01). All cases of death were related to comorbid conditions, not to PD therapy. Two patients were transferred to hemodialysis. We conclude that PD has proven to be a safe and comfortable therapy for renal replacement in patients over 65 years of age. Results are similar to results in younger patients.

Renal osteodystrophy in pediatric patients on peritoneal dialysis.

Renal osteodystrophy (ROD) is one of the mostfrequent complications in pediatric uremic patients on peritoneal dialysis (PD), and each case requires a different therapeutic approach. In the present study, we characterized ROD in pediatric patients on chronic PD. We studied 20 patients (12 boys, 8 girls) for a 12-month period. The mean age of the patients was 5.82 +/- 5 years. We allocated each patient to one of three groups according to intact parathormone (iPTH) value: group 1, iPTH < or = 150 pg/mL, n = 12; group 2, iPTH 151 - 400 pg/mL, n = 2; and group 3, iPTH > or = 401 pg/mL, n = 6. Monthly, we recorded plasma calcium, phosphorus, and alkaline phosphatase; Kt/V; normalized protein equivalent of total nitrogen appearance (nPNA); and calcitriol dose. Growth was registered as the Z height/age. Student t-test and analysis of variance for repeated measures were used for the statistical analyses. A value of p < 0.05 was considered significant. All 20 patients completed 6 months of follow-up; 9 patients completed 12 months. At months 1, 6, and 12, vitamin D doses for groups 1 and 3 were significantly different (p < 0.05), as expected. Mean values of iPTH for groups 1 and 3 were 52 +/- 47 pg/mL and 1239 +/- 718 pg/mL respectively, p < 0.05. At 6 months' follow-up, iPTH values had changed to 163 +/- 177 pg/mL for group 1 and 544 +/- 249 pg/mL for group 3 (p < 0.05), butfor group 3 that trend was lost at 12 months' follow-up, when their mean iPTH value rose to 972 +/- 420 pg/mL. Patients who had been started on PD less than 6 months before entering the study (60% of patients) showed a mean iPTH value of 629.13 pg/mL. Patients with more than 6 months on dialysis before entering the study showed an iPTH value of 115.53 pg/mL (p < 0.05). At 6 months' follow-up, iPTH values in groups 1 and 3 both showed a change toward the value range for group 2. At month 12, iPTH values in group 1 continued to show the same tendency, but iPTH values in group 3 showed a tendency to return to their initial levels. Low-turnover ROD was highly prevalent in the study, correlating strongly with time on dialysis.