Evaluation of a Legionella urinary antigen enzyme immunoassay for rapid detection of Legionella pneumophila in water samples

Despite advances in medium formulations and pretreatment techniques, recovery of Legionella from water samples can still be quite low, difficult and time consuming. The aim of this study was to evaluate the utility of a Legionella urinary antigen enzyme immunoassay (Bartels ELISA, Trinity Biotech, Ireland) for the detection of Legionella in water samples. Reference ATCC Legionella strains were used to spike water samples to a final concentration of 10(4)-10(5)cfu/ml. The lower detection limit of the test for all Legionella pneumophila serogroups was assessed by serial dilutions of spiked water samples. Legionella antigen was detected in all filtered samples except for those spiked with L. bozemanii and L. longbeachae. The lower detection limit for soluble L. pneumophila serogroup 1 antigen was 780cfu/ml. Bartels ELISA could be a useful method for antigen detection in water samples when a high recovery of L. pneumophila is suspected. The test could be used as a rapid screening method for the detection of Legionella in a large number of samples. However, the low sensitivity of the test requires to keep on performing conventional culture for isolation and for further studies on isolated bacteria.

Characterization of hepatitis B virus genotypes in chronically infected patients

Genomic mutations occurring during reverse transcription of hepatitis B virus (HBV) could explain its genetic diversity and account for 8 genetically distinct genotypes that are geographically distributed quite differently. The main objectives of this study were to determine the prevalence of hepatitis B virus genotypes in patients with chronic hepatitis B and to see if there was a relationship between genotypes and risk factors for transmission based on HBeAg status. A total of 14 serum samples were analyzed using INNO-LIPA HBV genotyping assay. Genotype D was the most prevalent (64.3%) followed by genotype A (28.6%). There was one case of co-infection (D/E genotypes) that was confirmed by PCR sequencing. All patients except one were HBeAg-negative and anti-HBe-positive. The risk factors for HBV transmission were unknown in half of the cases; in the other half, sexual, transfusion, maternal or interfamilial transmission were observed. The results show that genotype D is the most prevalent genotype in our hospital, followed by genotype A. On the other hand, no relationship was found between HBeAg status and genotype.

Prevalence of and risk factors for methicillin-resistant Staphylococcus aureus carriage at hospital admission

To determine the prevalence of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) carriage at the time of admission to our hospital, we screened the medical records of 1,128 patients for demographic and clinical data. The antimicrobial resistance pattern and genotype of MRSA isolates were studied. The prevalence of MRSA carriage at hospital admission was 1.4%. Older patients and patients previously admitted to healthcare centers were the most likely to have MRSA carriage at admission.

Atorvastatin Treatment in the Short Term: Does It Induce Renoprotection or Vasculoprotection in Renal Transplantation?

INTRODUCTION

Proteinuria and dyslipidemia are nonimmune risk factors implicated in the deterioration of kidney function and associated with an increased risk of accelerated atherogenesis. Statin therapy, used for cholesterol reduction, has shown a renoprotective effect in animal models, particularly in cases of proteinuria. This may occur through lipid-independent mechanisms, such as improved endothelial dysfunction/vascular biology, reduced inflammatory cytokine production (transforming growth factor-beta 1 [TGF-beta1]), and regulation of fibrogenic responses. We studied mechanisms of action of agents, such as statins, to change proteinuria, inflammatory parameters, and TGF-beta1 plasma levels in relation to vascular tone.

METHODS

Fifty-six kidney transplant recipients (30 men and 26 women of overall mean age 54 +/- 13 years) were treated posttransplantation with atorvastatin (10 mg/d) for 12 weeks without renin-angiotensin-system blockade drugs. Inflammatory variables, biochemical parameters, lipid profile, renal function, and TGF-beta1 levels were determined at baseline and at 3 months. Vascular stiffness was evaluated using pulse wave velocity (PWV).

RESULTS

Baseline TGF-beta1 plasma levels were higher among transplant recipients than healthy controls, namely 8.12 ng/mL (range, 5.82-13.12) to 2.55 (range, 1.78- 4.35) (P < .01). Furthermore, the levels remained higher after the treatment with atorvastatin, namely, 7.59 (range, 4.97-12.35) to 2.55 (range, 1.78-4.35) ng/mL (P < .01). Atorvastatin treatment significantly decreased total cholesterol as well as low-density lipoprotein cholesterol plasma levels, but did not modify mean blood pressure (MBP), proteinuria, creatinine clearance, or inflammatory factors. Reduction in TGF-beta1 plasma levels was statistically significant among patients with PWV >9.75 (m/s) (pathology reference value) namely, from 10.7 ng/mL (range, 7.02-13.98) to 6.7 (range, 3.96-11.94) (P = .038). Among older patients, atorvastatin significantly decrease TGF-beta1 plasma levels: from 9.5 ng/mL (range, 6.45-14.44) to 5.65 (range, 3.63-9.48; P < .05). The decreased TGF-beta1 was not related to changes in lipid profiles.

CONCLUSIONS

Atorvastatin (10 mg/d) improved the lipid profile and moreover among older patients with worse PWV (>9.75 m/s), TGF-beta1 levels were significantly reduced. Our results suggested that statins displayed potent actions distinct from their hypolipidemic effects.

Riesgo de perforación en la mucosectomía esofágica con banda: estudio experimental con dos modelos de ligadores

OBJECTIVE

endoscopic mucosal resection with ligation (EMRL) is considered an efficient, safe method for the treatment of some esophageal, gastric and colorectal tumors. We conducted this study using a porcine model in order to compare the safety of esophageal EMRL with two multiband ligation systems, since many centers only use these ligator models in EMRL (commercialized for varix ligation).

METHODS

eight pigs were used, which were submitted to 23 esophageal resections without previous injection. Ten resections were conducted using the Six Shooter Saeed model, and 13 resections used the Speedband Superview Super 7 model. The technique was also compared by making random cuts either above or below the band.

RESULTS

five perforations occurred, all of them using the Speedband model. This represents 38.5% of total in the Speedband model group. No perforation occurred when using the Six Shooter model (p = 0.046). On the contrary, no significant differences were found regarding frequency of perforation when cutting above or below the band.

CONCLUSIONS

esophageal EMRL using the Speedband model without previous injection leads to perforation in a high percentage of cases in an experimental animal model. Further studies are required to find out whether a previous injection may increase the safety of this technique with this ligator model.

[Resistance index to epoetin alpha and to darbepoetin-alpha in chronic hemodialysis patients: a cohort study]

The effectiveness of the erythropoietic response can be evaluated using the resistance index (RI) to erythropoietic agents (EA) that measures the relationship between the dose administered and the hemoglobin levels attained. In a hemodialysis population, the RI is associated with several clinical and biochemical parameters, such as albumin levels, C-reactive protein (CRP), body mass index (BMI) and Kt/V. This index therefore reflects an important group of parameters that indicate comorbidities and measures the effectiveness of the treatment received. A substantial proportion of chronic hemodialysis patients show a relative resistance to human recombinant erythropoietin (rHuEPO) and require high doses to reach hemoglobin levels above 11 g/dl. Darbepoetin alpha is a new erythropoietic agent with a longer half-life than rHuEPO and greater biological activity in vivo. Furthermore, it remains at clinically effective plasma levels for much longer than rHuEPO. This study evaluated the effect on RI of switching from epoetin alpha to darbepoetin alpha in hemodialysis patients requiring i.v. rHuEPO at either high ( >10,000 UI/w) or low ( <4,000 UI/w) doses, compared to a control group receiving epoetin alpha. Unlike the control group, both groups of patients who switched to darbepoetin alpha showed a reduction in RI and a progressive reduction in the dose required of darbepoetin alpha with respect to the equivalent dose at treatment conversion. In the group requiring high doses, darbepoetin alpha RI (DRI) at week 24 was a significant 23.9% lower than epoetin alpha RI (ERI) at conversion (week 0) (p <0.01). In the group requiring low doses, DRI at week 24 was 13.4% lower than the ERI at conversion (p = NS). In both control groups, ERI at week 24 was higher than ERI at week 0. All groups showed stable hemoglobin levels across the study, with mean levels between 11.5 and 13.3 g/dl. CRP at week 24 was significantly related to albumin levels (p <0.001). In conclusion, switching hemodialysis patients from epoetin alpha to darbepoetin alpha was associated with a significant improvement in RI in the group of patients with high doses of EA, which we consider to be an important indicator of the effectiveness and quality of the treatment administered.

Rapid detection of pneumococcal antigen in serum samples for diagnosing pneumococcal pneumonia

OBJECTIVES

The aim of the study is to assess the usefulness of C polysaccharide and polysaccharide capsular antigen detection by immunochromatography (ICT) and enzyme immunoassay (EIA), respectively, in serum samples for diagnosing pneumococcal pneumonia.

METHODS

Adult patients included in the study were classified in the following groups: In group 1 we studied 101 serum samples from patients with pneumonia due to Streptococcus pneumoniae. In 53 cases the pneumonia was bacteremic. The second group contained 113 serum samples from patients with no pneumococcal pneumonia. Group 3 was made up of 40 serum samples from healthy subjects with no clinical or radiological signs of pneumonia.

RESULTS

Using ICT, antigen was detected in 50% of patients with pneumococcal pneumonia, in 64.3 and 40.9% of patients with bacteremic and non-bacteremic pneumococcal pneumonia, respectively. Using EIA, antigens were detected in 35.8% of patients with pneumococcal pneumonia, in 45 and 22.2% of patients with bacteremic and non-bacteremic pneumococcal pneumonia, respectively.

CONCLUSIONS

In conclusion, the sensitivity of the tests is low. However, in special situations, where obtaining large volume of urine is difficult, they could be a complementary method in the rapid diagnosis of pneumococcal pneumonia.

Usefulness of pneumococcal antigen detection in pleural fluid samples by immunochromatographic assay for diagnosis of pneumococcal pneumonia

This study investigated the utility of an immunochromatographic test (ICT) for the detection of Streptococcus pneumoniae antigens in pleural fluid. Antigen was detected in 15 of 19 (79%) patients with pneumococcal pneumonia. The ICT was always negative in patients with non-pneumococcal pneumonia, but was positive in three cases with a non-infectious aetiology. In patients with pneumonia for which no pathogen was identified, antigen was detected in one of 24 pleural fluids tested. The ICT can be a valuable tool for the management of pneumonia because it can detect pneumococcal antigen in pleural effusion samples.

Comparison of a monoclonal with a polyclonal antibody-based enzyme immunoassay stool test in diagnosing Helicobacter pylori infection before and after eradication therapy

BACKGROUND

Detection of Helicobacter pylori antigen in stool samples has been a subject of controversy. However, it has been included in several clinical guidelines as a recommended non-invasive testing procedure in dyspeptic patients.

AIM

To compare a monoclonal enzyme immunoassay for detection of H. pylori stool antigen (Amplified IDEIA HpStAR, DakoCytomation) with a polyclonal enzyme immunoassay (HpSA test, Premier Platinum HpSA, Meridian Diagnostics) in diagnosing infection and in determining H. pylori status after eradication treatment.

METHODS

We evaluated stool samples of 198 patients diagnosed with H. pylori infection and of 41 patients without infection. The results of the monoclonal enzyme immunoassay HpStAR were compared with those of the polyclonal enzyme immunoassay HpSA.

RESULTS

The sensitivity and specificity of HpStAR were 91.9% and 70.7%, while those of HpSA were 89.4% and 80.5%, respectively. In the 126 patients evaluated 6 weeks after eradication therapy, the overall agreement between urea breath test and HpStAR was 90.5% (P = 0.710) and between urea breath test and HpSA was 76.9% (P = 0.410).

CONCLUSIONS

HpStAR is a rapid and easy-to-perform test with similar sensitivity to HpSA in the diagnosis of H. pylori infection, although it had lower specificity. In contrast, HpStAR is more accurate after eradication therapy than HpSA.

DNA damage in outdoor workers occupationally exposed to environmental air pollutants

BACKGROUND

Health concerns about the exposure to genotoxic and carcinogenic agents in the air are particularly significant for outdoor workers in less developed countries.

AIMS

To investigate the association between personal exposure to a group of air pollutants and severity of DNA damage in outdoor workers from two Mexican cities.

METHODS

DNA damage (Comet assay) and personal exposure to volatile organic compounds, PM(2.5), and ozone were investigated in 55 outdoor and indoor workers from México City and Puebla.

RESULTS

In México City, outdoor workers had greater DNA damage, reflected by a longer tail length, than indoor workers (median 46.8 v 30.1 mum), and a greater percentage of highly damaged cells (cells with tail length > or =41 microm); in Puebla, outdoor and indoor workers had similar DNA damage. There were more alkali labile sites in outdoor than indoor workers. The DNA damage magnitude was positively correlated with PM(2.5) and ozone exposure. Outdoor and indoor workers with > or =60% of highly damaged cells (highly damaged workers) had significantly higher exposures to PM(2.5), ozone, and some volatile organic compounds. The main factors associated with the highly damaged workers were ozone, PM(2.5), and 1-ethyl-2-methyl benzene exposure.

CONCLUSIONS

With this approach, the effects of some air pollutants could be correlated with biological endpoints from the Comet assay. It is suggested that the use of personal exposure assessment and biological endpoints evaluation could be an important tool to generate a more precise assessment of the associated potential health risks.

Use of a mycobacteriophage-based assay for rapid assessment of susceptibilities of Mycobacterium tuberculosis isolates to isoniazid and influence of resistance level on assay performance

We standardized and assessed the performance of an in-house microtiter assay for determining the susceptibilities of Mycobacterium tuberculosis clinical isolates to isoniazid based on mycobacteriophage amplification technology. Seventy isolates (43 resistant and 27 sensitive according to the BACTEC 460 radiometric method and MIC determination) were studied. The isoniazid resistance molecular mechanism was previously determined by sequencing the entire katG gene and the mabA-inhA regulatory region. The sensitivity of the mycobacteriophage-based assay in detecting isoniazid resistance was 86.1%, the specificity achieved was 92.6%, and the overall accuracy was 88.6%. In order to assess the possible influence of resistance levels on the mycobacteriophage-based-assay sensitivity, the results were analyzed according to the isoniazid MICs. All the isolates exhibiting high-level resistance (MIC > or = 2 microg/ml) were scored as resistant by the mycobacteriophage-based assay (100% concordance), and 95% showed mutations or deletions in the catalytic domain of the katG gene. In contrast, 26.1% of the low-level-resistance strains (MICs, 0.25 to 1 microg/ml) were misclassified, and 66.7% had alterations in the mabA-inhA regulatory region. The mycobacteriophage-based assay could be used as a rapid method to detect the isoniazid susceptibility pattern, although data from those areas with high rates of low-level-resistance strains should be interpreted with caution. The features of the assay make it suitable for widespread application due to its low technical demand and cost.

Procalcitonin and neopterin correlation with aetiology and severity of pneumonia

OBJECTIVE

Clinical outcome of pneumonia depends on a multifaceted treatment approach. Not only diagnostic methods but also early indicators of the degree of inflammatory response can aid in therapeutic decisions. The objective was to evaluate the usefulness of procalcitonin and neopterin in distinguishing among aetiologies as well as severity in patients with pneumonia.

PATIENTS

A total of one hundred sixteen patients with clinical, radiographic and microbiological diagnosis of pneumonia were grouped by aetiology, pneumonia severity index, and by the presence of unilobar or multilobar radiographic pulmonary infiltrates. Procalcitonin and neopterin were measured by immunoassays.

RESULTS

Patients with pneumococcal pneumonia presented elevated procalcitonin and neopterin levels, being higher in bacteraemic than in non-bacteraemic pneumonia. Patients with Legionella pneumonia presented elevated neopterin levels and slightly elevated procalcitonin levels. Patients with tuberculosis and Pneumocystis jirovecii pneumonia presented elevated neopterin and low or not detectable procalcitonin. Procalcitonin and neopterin levels were increased in high-risk classes of pneumonia severity index. Both parameters yielded significant correlation to the radiographic extent and also to young age.

CONCLUSIONS

Procalcitonin and neopterin levels vary depending on age, aetiology and severity of pneumonia. Together with clinical and microbiological data, combined measurement can help to identify patients who might benefit from additional therapies.

Impact of rapid urine antigen tests to determine the etiology of community-acquired pneumonia in adults

STUDY OBJECTIVES

To evaluate the rapid urine antigen tests, including a new rapid immunochromatographic test (ICT) for the detection of the Streptococcus pneumoniae antigen and an enzyme immunoassay (EIA) for the detection of the Legionella antigen, in order to improve the diagnosis of community-acquired pneumonia (CAP) in adults.

DESIGN

Prospective study.

SETTING

A tertiary hospital in Spain.

PATIENTS

We consecutively recruited 107 adults with CAP evaluated at our hospital.

INTERVENTIONS

The analyses included blood and sputum cultures, pleural fluid culture (if present) and serologic studies. The detection of the Legionella pneumophila urinary antigen was performed by EIA, and the detection of S. pneumoniae antigen in urine samples was performed by counterimmunoelectrophoresis (CIE) and a rapid ICT.

RESULTS

Using conventional microbiologic tests we succeeded in performing the etiologic diagnosis of 39 out of the 107 cases (36.4%). The inclusion of rapid antigen detection techniques increased the percentage of diagnosis to 54.2%, which represents a total increase of 17.8% (P=0.034).

CONCLUSIONS

The data obtained in this study indicate that rapid urine antigen tests are very useful to determine CAP etiology in adults and, consequently, to quickly identify a group of patients in whom narrow spectrum antibiotics may be used.

A new test of random walks in heterogeneous environments

Environmental heterogeneities can change animal movement in two different manners. First, they can modify movement characteristics (move lengths or turning angles), in which case the movement remains of the diffusive kind. Second, they can bias displacement towards a particular direction in which case it becomes non-diffusive. We propose in this paper a simple method that only requires computing the mean length of a sample of trajectories in some bounded area to distinguish between these two kinds of movement. We show through simulations that the method allows to detect the presence of heterogeneities that orient animal movement. We apply it to experimental trajectories of Messor sancta ants engaged in corpse aggregation to show that their displacement is oriented at the contact of the formed corpse piles and that their trajectories become non-diffusive.

Constitutive nitric oxide synthases are responsible for the nitric oxide production in the ischemic aged cerebral cortex

Aged brain shows reduced biological plasticity to meet emergency conditions such as ischemia, a process in which nitric oxide (NO) and apoptosis have been shown to play important roles. Using a model of transient global ischemia, we have analyzed the NO system and the p53, bax and bcl-2 response in the cerebral cortex of aged rats. Although immediately after ischemia the NO level is maintained, the reperfusion period increases NO concentrations together with the following: (i) greater bulk-protein nitration mainly due to a 50-kDa immunoreactive band; (ii) an increase in p53 protein; and (iii) an up-regulation of Bax together with a down-regulation of Bcl-2. These results match up with induced endothelial nitric oxide synthase expression immediately after ischemia and in neuronal nitric oxide synthase with the reperfusion. However, inducible nitric oxide synthase was not altered with ischemia/reperfusion. Altogether, these data suggest that NO production in cerebral cortex of aged ischemic animals is due to the constitutive NO synthase isoforms. This response is accompanied by the increased expression of pro-apoptotic proteins.

Upregulation of endothelial nitric oxide synthase maintains nitric oxide production in the cerebellum of thioacetamide cirrhotic rats

This study examines the expression and cellular distribution pattern of nitric oxide synthase (NOS) isoforms, nitrotyrosine-derived complexes, and the nitric oxide (NO) production in the cerebellum of rats with cirrhosis induced by thioacetamide (TAA). The results showed local changes in the tissue distribution pattern of the NOS isoforms and nitrated proteins in the cerebellum of these animals. Particularly, eNOS immunoreactivity in perivascular glial cells of the white matter was detected only in TAA-treated animals. In addition, although neither neuronal NOS (nNOS) nor inducible NOS (iNOS) cerebellar protein levels appeared to be affected, the endothelial NOS (eNOS) isoform significantly increased its expression, and NO production slightly augmented in TAA-treated rats. These NOS/NO changes may contribute differently to the evolution of the hepatic disease either by maintaining the guanosine monophosphate-NO signal transduction pathways and the physiological cerebellar functions or by inducing oxidative stress and cell damage. This model gives rise to the hypothesis that the upregulation of the eNOS maintains the physiological production of NO, while the iNOS is silenced and the nNOS remains unchanged. The differential NOS-distribution and expression pattern may be one of the mechanisms involved to balance cerebellar NO production in order to minimize TAA toxic injury. These data help elucidate the role of the NOS/NO system in the development and progress of hepatic encephalopathy associated with TAA cirrhosis.

Spontaneous rupture of renal leiomyosarcoma in a 45-year-old woman

OBJECTIVES

Leiomyosarcoma is a rare histological subtype of renal sarcomas, accounting for approximately 50-60% of the reported cases. Spontaneous rupture of renal tumor is an uncommon event and the most frequent cause is angiomyolipoma. We report a case of spontaneous rupture of leiomyosarcoma in a 45-year-old woman, presenting with severe left flank pain and perirenal hemorrhage.

METHODS

A 45-year-old caucasian white woman was transferred to our department from emergency room of a different Hospital for acute left flank pain interpreted as a renal colic not responsive to medical therapy. On clinical examination patient was haemodynamically stable but with rapid decrease in hemoglobin, pale, without haematuria with a persistent left flank and hypochondrium pain as in acute abdomen. CT scan of abdomen showed a retroperitoneal haematoma around the left kidney, and a large heterogeneous mass.

RESULTS

Laparotomy was urgently performed. There was large retroperitoneal hematoma extending from left kidney to pelvic space. At the upper pole of the kidney a bleeding tumor was found. Radical nephrectomy was performed. The histological diagnosis was of low-grade leiomyosarcoma from renal angiomyolipoma.

CONCLUSIONS

We attract attention both on kidney cancer (at our knowledge only 3 cases described in literature) and on the need of imaging in the clinical approach of renal colic. We strongly believe that the patients presenting at emergency for renal colic must be scanned by ultrasounds or TC.

Q fever: a new cause of 'doughnut' granulomatous lobular panniculitis

Q fever is an uncommon zoonotic rickettsial disease with no exanthem or specific cutaneous lesions. Only nonspecific cutaneous involvement has been reported to date. A 69-year-old Spanish woman with chronic myelogenous leukaemia developed fever and two subcutaneous nodules. The patient complained of extreme pain. Biopsy revealed a granulomatous lobular panniculitis with a characteristic 'fibrin ring' or 'doughnut' appearance: fibrin and inflammatory cells arranged around a central clear space. Changes of membranous lipodystrophy were also found. Q fever serological studies were positive. Our patient had panniculitis with singular histopathological features. These histopathological changes have been described in liver and bone marrow of patients with Q fever. To the best of our knowledge, this cutaneous involvement due to Q fever has not previously been described in the literature.

Synthesis of alkyl-alpha-L-rhamnosides by water soluble alcohols enzymatic glycosylation

The synthesis of alkyl-alpha-rhamnosides by alpha-rhamnosidase was studied using rhamnose and rhamnosides, particularly the flavonoid naringin, as glycosylation agents, and water soluble alcohols as acceptors. The reaction products were analyzed by HPLC chromatography and identified by 13C y 1H NMR. The glycosylation of alcohols by reverse hydrolysis was maximum for 40% methanol, 30% ethanol, 10% propanol and 20% isopropanol. Under optimum conditions the yield of rhamnose to alkyl-alpha-rhamnoside transformation decreased from 68% for methyl-alpha-rhamnoside to 10% for isopropyl-alpha-rhamnoside. The time course of rhamnosylations produced using naringin as the donor was comparable with that of the reverse hydrolysis obtained at the same molar concentration of the donor. The flavonoids and their derivatives remaining in the solution after the glycosylation were removed by ion exchange QEAE chromatography at pH 10. These results indicate that both, reverse hydrolysis and glycosylation by naringin are acceptable procedures for the enzymatic synthesis of short chain length alkyl-alpha-L-rhamnosides.

[Hepatitis C virus variability and interferon-mediated pathway inhibition]

The most important aim of this study was to describe the hypothetical relationship between the PePHD region variability (related to the synthesis of a cellular enzyme pseudosubstrate) of the hepatitis C virus and the response of patients to interferon therapy. This interaction could be a determining factor in the antiviral effect of interferon. All samples (from 24 patients with chronic hepatitis C infection) were analyzed using a previously described method based on RT-PCR and nested PCR mediated by single-strand conformation polymorphism assay (SSCP). The patients were divided into three groups with respect to the response to therapy: 8 patients with sustained response, 8 patients with transient response and 8 nonresponders. In all samples a low genetic heterogeneity pattern was detected, which was independent of other factors involved in the lack of response to treatment, such as age, sex or viral genotype. This genetic homogeneity is an indirect indication of the importance of the region on viral persistence. However, more studies are needed to evaluate the real role of this sequence on the interaction between cells and the virus.

Usefulness of a new mycobacteriophage-based technique for rapid diagnosis of pulmonary tuberculosis

A new mycobacteriophage-based technique (PhageTek MB) was compared with standard culture and staining techniques for diagnosis of pulmonary tuberculosis. A total of 2,048 respiratory specimens from 1,466 patients collected from February 2000 to March 2001 were studied by both (i) conventional methods (direct microscopic examination [auramine-rhodamine fluorochrome], and culture in BacT/ALERT 3D and solid media) and (ii) the PhageTek MB assay. This phenotypic test utilizes specific mycobacteriophages to detect the presence of live Mycobacterium tuberculosis complex organisms within a decontaminated clinical sample. Overall, 205 (10%) specimens were positive for mycobacteria (134 patients): 144 (70.2%) M. tuberculosis isolates and 61 (29.8%) nontuberculous mycobacterium isolates (30 Mycobacterium kansasii, 12 Mycobacterium xenopi, 9 Mycobacterium gordonae, 7 Mycobacterium avium complex, 2 Mycobacterium chelonae, and 1 Mycobacterium fortuitum isolate). PhageTek MB was more likely to give a positive result with specimens in which high numbers of acid-fast bacilli were observed on the smear. The sensitivity, specificity, and positive and negative predictive values of this mycobacteriophage-based technique versus culture for M. tuberculosis were 58.3, 99.1, 83.2, and 96.9%, respectively. PhageTek MB is a rapid (48-h), specific, safe, and easy-to-perform test. According to the prevalence of the disease in the population studied, the test would require improved sensitivity in order to be used as a screening test for routine diagnosis of respiratory tuberculosis in our setting.

Utility of an in-house mycobacteriophage-based assay for rapid detection of rifampin resistance in Mycobacterium tuberculosis clinical isolates

A rapid in-house mycobacteriophage-based assay to identify multidrug resistance by detecting the rifampin susceptibility of Mycobacterium tuberculosis in a microtiter plate format was evaluated. The sensitivity, specificity, and overall accuracy of the assay were 100%. This test is rapid to perform and suitable for widespread implementation.

Usefulness of urinary antigen detection by an immunochromatographic test for diagnosis of pneumococcal pneumonia in children

We evaluated an immunochromatographic assay detecting pneumococcal antigen in urine samples from children diagnosed with pneumococcal pneumonia. The sensitivity and specificity of the immunochromatographic test with nonconcentrated urine (NCU) were 86.7 and 62.9%, respectively; with concentrated urine (CU), they were 100 and 11.7%, respectively. Pneumococcal antigen was also detected in 42.5% of NCU and 87.1% of CU samples from nasopharyngeal carriers. This is a nonspecific test for the diagnosis of pneumococcal pneumonia in children, particularly the very young.

[Viral quasispecies and their implications in antiviral therapy]

The aim of this study was to evaluate the relationship between the quasispecies in the HVR1 region of the hepatitis C virus and treatment evolution in order to determine whether genetic complexity is predictive of response to interferon therapy. The samples were analyzed by nested RT-PCR-mediated single-strand conformation polymorphism assay (SSCP). Twelve patients with chronic hepatitis C were studied and divided into three groups: three patients with sustained response, three patients with transient response and six nonresponders. The patients in the sustained response group showed a low genetic complexity pattern. By contrast, in three nonresponders and in one patient with transient response, the SSCP assay revealed a high complexity pattern. With regard to the remaining patients with transient response, new SSCP bands appeared, thereby modifying their genetic complexity pattern. Therefore, nonresponse to interferon treatment could be related to the presence of a high genetic complexity pattern, while the detection of a low genetic complexity pattern is necessary for a positive response to interferon therapy. Due to the limited number of patients involved in this study, it was not possible to predict the response to interferon based on the genetic complexity pattern. Larger studies are therefore required.

Assessment of a new test to detect Legionella urinary antigen for the diagnosis of Legionnaires' Disease

Given that the rate of mortality by Legionella pneumonia increases in incorrectly treated patients, rapid diagnosis and early antibiotic treatment are needed. We have assessed the performance of a new enzyme immunoassay (EIA) test (Bartels Inc. Trinity Biotech Company, Wicklow, Ireland) to detect Legionella pneumophila antigen in urine comparing it to Binax EIA (Binax, Portland, Maine). We also evaluated the capability of both EIAs to detect extracted soluble antigens of Legionella strains. Using nonconcentrated urine samples (NCU) the sensitivity of Bartels EIA was 74.1% (66/89) and the sensitivity of Binax EIA was 51.7% (46/89). The sensitivity of both EIA tests were 91.5% (54/59) using concentrated urine samples (CU). Specificity of both EIA tests was 100% in NCU and CU. Bartels EIA was able to detect all serogroup L. pneumophila antigens, achieving a higher sensitivity in the case of L. pneumophila serogroup 1 soluble antigen. The new EIA was found to be a useful test for the rapid diagnosis of Legionella pneumonia, being a better alternative to the Binax EIA if NCU is used.

Immunohistochemical localisation of neuronal nitric oxide synthase in the rainbow trout kidney

The distribution of nitrergic nervous structures in the trout kidney was studied by peroxidase-linked ABC immunostaining procedures using a polyclonal antibody raised against the neuronal isoform of nitric oxide synthase. The nitrergic plexus reaches the kidney along the vasculature, mainly running with the postcardinal vein where nitrergic fibres, microganglia like cellular clusters and isolated neurones were detected. The atubular head-kidney only showed isolated nitrergic fibres close to the larger arteries. On the other hand, the collecting tubules, collecting ducts, large arteries and glomerular arterioles of the tubular middle and posterior trunks were innervated by nitrergic fibres even though immunoreactive neurones were also observed in close apposition to some tubular elements and large arteries. These results suggest that, according to morphofunctional differences between the fish and mammalian kidneys, nitrergic neural structures may be involved in the control of particular renal functions in the rainbow trout.

Wavelet entropy: a new tool for analysis of short duration brain electrical signals

Since traditional electrical brain signal analysis is mostly qualitative, the development of new quantitative methods is crucial for restricting the subjectivity in the study of brain signals. These methods are particularly fruitful when they are strongly correlated with intuitive physical concepts that allow a better understanding of brain dynamics. Here, new method based on orthogonal discrete wavelet transform (ODWT) is applied. It takes as a basic element the ODWT of the EEG signal, and defines the relative wavelet energy, the wavelet entropy (WE) and the relative wavelet entropy (RWE). The relative wavelet energy provides information about the relative energy associated with different frequency bands present in the EEG and their corresponding degree of importance. The WE carries information about the degree of order/disorder associated with a multi-frequency signal response, and the RWE measures the degree of similarity between different segments of the signal. In addition, the time evolution of the WE is calculated to give information about the dynamics in the EEG records. Within this framework, the major objective of the present work was to characterize in a quantitative way functional dynamics of order/disorder microstates in short duration EEG signals. For that aim, spontaneous EEG signals under different physiological conditions were analyzed. Further, specific quantifiers were derived to characterize how stimulus affects electrical events in terms of frequency synchronization (tuning) in the event related potentials.

Maternal and congenital syphilis in Bolivia, 1996: prevalence and risk factors

OBJECTIVES

The present study was carried out in seven maternity hospitals to determine the prevalence of maternal syphilis at the time of delivery and the associated risk factors, to conduct a pilot project of rapid syphilis testing in hospital laboratories, to assure the quality of syphilis testing, and to determine the rate of congenital syphilis in infants born to women with syphilis at the time of delivery--all of which would provide baseline data for a national prevention programme in Bolivia.

METHODS

All women delivering either live-born or stillborn infants in the seven participating hospitals in and around La Paz, El Alto, and Cochabamba between June and November 1996 were eligible for enrolment in the study.

FINDINGS

A total of 61 out of 1428 mothers (4.3%) of live-born infants and 11 out of 43 mothers (26%) of stillborn infants were found to have syphilis at delivery. Multivariate analysis showed that women with live-born infants who had less than secondary-level education, who did not watch television during the week before delivery (this was used as an indicator of socioeconomic status), who had a previous history of syphilis, or who had more than one partner during the pregnancy were at increased risk of syphilis. While 76% of the study population had received prenatal care, only 17% had syphilis testing carried out during the pregnancy; 91% of serum samples that were reactive to rapid plasma reagin (RPR) tests were also reactive to fluorescent treponemal antibody-absorption (FTA-ABS) testing. There was 96% agreement between the results from local hospital laboratories and national reference laboratories in their testing of RPR reactivity of serum samples. Congenital syphilis infection was confirmed by laboratory tests in 15% of 66 infants born to women with positive RPR and FTA-ABS testing.

CONCLUSION

These results indicate that a congenital syphilis prevention programme in Bolivia could substantially reduce adverse infant outcomes due to this disease.

Detection of Streptococcus pneumoniae antigen by a rapid immunochromatographic assay in urine samples

STUDY OBJECTIVES

Evaluation of a newly available rapid (15 min) immunochromatographic membrane test (ICT) to detect Streptococcus pneumoniae in urine samples, in order to assess its utility in the diagnosis of bacteremic and nonbacteremic pneumococcal pneumonia.

DESIGN

Retrospective study.

SETTING

We studied urine samples from 51 patients with bacteremic and nonbacteremic pneumonia due to S pneumoniae diagnosed by blood culture and pneumococcal polysaccharide capsular antigen detection by counterimmunoelectrophoresis in urine samples, 16 patients with probable pneumococcal pneumonia, 71 patients with nonpneumococcal pneumonia, and 16 patients with pneumonia but no pathogen identified. Urine samples were collected and frozen at - 20 degrees C until used. The ICT test was performed following the instructions of the manufacturer.

MEASUREMENTS AND RESULTS

S. pneumoniae antigen was detected in 41 of 51 patients with pneumococcal pneumonia (80.4%); results were positive in 23 of 28 bacteremic cases (82.1%) and in 18 of 23 nonbacteremic cases (78.3%). From patients with a diagnosis of presumptive pneumococcal pneumonia, antigen was detected in seven urine samples (43.7%) and also in one case of the 16 patients with pneumonia but no pathogen identified. The specificity of the ICT test was 97.2%.

CONCLUSION

The ICT assay is a valuable tool for the diagnosis of pneumococcal pneumonia, especially for the nonbacteremic cases.

[Aging and neurodegeneration: molecular and cellular bases]

OBJECTIVE

A review about the possible cellular and molecular mechanisms of aging and related neurodegenerative diseases.

DEVELOPMENT

The mechanisms involved in neuronal decrease, connectivity losses and glial reactivity, detected both in neurodegenerative (Alzheimer's disease) and physiological aging, are analyzed from the morphological and histological point of view to provide the morphofunctional base of the cognitive and intellectual alterations characterizing the senescence process. Taken together, these data are correlated to the possible genetical aspects implied in this process, reviewing the most relevant results on senescence and cellular death obtained from yeast, fruit fly and nematodes; besides this, a brief review of the molecular biology of gerontogenes was carried out, and the possible mechanisms inducing aging and neurodegenerative processes are analyzed according to the state-of-the-art related theories. Finally, cellular, biochemical and genetical data are correlated in the signal transduction way implied in the increase of the intracellular calcium level as the starting point of cell death.

CONCLUSIONS

The main process implied in the neuronal cell death responsible for aging and the related neurodegenerative diseases are started by different agents such as the lacking of neurotrophic factors, hypoxia, hypoglycemia, excitotoxicity, and oxygen and nitrogen free radicals.

[Evaluation of commercial equipment used in blood banks in Córdoba for the detection of anti-HTLV-I/II antibodies]

In order to assess the efficiency of currently used screening tests, Abbott HTLV-I/HTLV-II EIA, Vironostika HTLV-I/II Organon Teknika, Particle Agglutination (PA) assay Serodia Fujirebio Inc. (Tokyo, Japan) for HTLV-I/II antibody detection in blood donors samples, a panel of 100 sera from different blood banks of Córdoba city were studied. An "in house" indirect immunofluorescence assay (IFA) was used as reference test. The correlation rates were: 66% for Abbott HTLV-I/HTLV-II EIA, 97% for Vironostika HTLV-I/II Organon Teknika EIA and 99% for PA Serodia. Vironostika HTLV-I/II Organon Teknika EIA and PA Serodia assay proved to be more reliable for HTlV-I/II antibody screening in blood donors from Córdoba, yielding a very low rate of false positive results as compared with Abbot HTLV-I/HTLV-II EIA.

Postsurgical pleurodesis with autologous blood in patients with persistent air leak

BACKGROUND

Persistent air leak after operation on the lung is one of the most common problems encountered by thoracic surgeons. We present 6 patients who underwent pleurodesis with autologous blood for persistent air leak after operation.

METHODS

Between June 1993 and January 1998, pleurodesis with autologous blood was performed in 6 patients who had air leak of more than 10 days' duration after operation for non-small cell lung cancer. A sample of peripheral blood was taken from the patient's arm and immediately introduced into the chest tube with no additives. The chest tube was left unclamped and off suction, connected to the waterseal drainage, and kept 60 cm above the patient's chest. The next day, the waterseal and chest roentgenogram were reviewed before the chest tube was removed.

RESULTS

A persistent air leak with a mean duration of 16.7 days was observed after the initial operation. Fifty to 250 mL of blood was introduced one time into the chest tube. No patient experienced pain, respiratory difficulty, fever, or episodes of coughing during the procedure. After 24 hours, no air leak was detected in the waterseal drainage in any patient.

CONCLUSIONS

On the basis of these preliminary findings, we believe pleurodesis with autologous blood is a safe and effective method for treating persistent air leak after a thoracic surgical procedure.