Observations of the missing baryons in the warm-hot intergalactic medium.

It has been known for decades that the observed number of baryons in the local Universe falls about 30-40 per cent short1,2 of the total number of baryons predicted 3 by Big Bang nucleosynthesis, as inferred4,5 from density fluctuations of the cosmic microwave background and seen during the first 2-3 billion years of the Universe in the so-called 'Lyman α forest'6,7 (a dense series of intervening H I Lyman α absorption lines in the optical spectra of background quasars). A theoretical solution to this paradox locates the missing baryons in the hot and tenuous filamentary gas between galaxies, known as the warm-hot intergalactic medium. However, it is difficult to detect them there because the largest by far constituent of this gas-hydrogen-is mostly ionized and therefore almost invisible in far-ultraviolet spectra with typical signal-to-noise ratios8,9. Indeed, despite large observational efforts, only a few marginal claims of detection have been made so far2,10. Here we report observations of two absorbers of highly ionized oxygen (O VII) in the high-signal-to-noise-ratio X-ray spectrum of a quasar at a redshift higher than 0.4. These absorbers show no variability over a two-year timescale and have no associated cold absorption, making the assumption that they originate from the quasar's intrinsic outflow or the host galaxy's interstellar medium implausible. The O VII systems lie in regions characterized by large (four times larger than average 11 ) galaxy overdensities and their number (down to the sensitivity threshold of our data) agrees well with numerical simulation predictions for the long-sought warm-hot intergalactic medium. We conclude that the missing baryons have been found.

Lung Cancer Presents at a Younger Age and Is Less Likely to be Curable in People Living with HIV.

INTRODUCTION: Globally, lung cancer remains the leading cause of malignancy-related death in men and women. There is increasing evidence that the risk for lung cancer in people living with human immunodeficiency virus (PLHIV) is higher than that of the general population. Given the high burden of PLHIV and lung cancer in Southern Africa, we aimed to compare the characteristics of PLHIV and HIV-negative lung cancer patients with regards to demographics, cell type, performance status, and tumour stage at presentation. METHODS: All patients who presented to a large tertiary hospital over a 7-year period with a confirmed tissue diagnosis of primary lung cancer were included in a prospective registry. The patient demographics, HIV status, as well as the patients' performance status according to the Eastern Cooperative Oncology Group (ECOG) were documented. RESULTS: The cohort consisted of 1,805 patients (mean age 60.0 years) of which 1,129 were male. In total, 133 were PLHIV and 1,292 were confirmed HIV-negative, while the remaining were categorised as HIV-unknown. PLHIV with lung cancer were found to be younger than the HIV-negative group (mean [±SD] 54.6 [9.3] versus 60.3 [10.1], p < 0.001). Notably, not a single PLHIV was diagnosed with resectable non-small cell lung cancer (NSCLC), and only 7 of 133 (6.5%) had potentially curable disease NSCLC (up to stage IIIB) compared to 240 of 1292 HIV-negative patients (27.7%, p < 0.001). CONCLUSION: PLHIV with lung cancer were diagnosed at a significantly younger age and were significantly less likely to have curable NSCLC at presentation.

Effects of functional ingredients on gut inflammation in Atlantic salmon (Salmo salar L).

Functional feed ingredients are frequently used in feeds for Atlantic salmon, often claimed to improve immune functions in the intestine and reduce severity of gut inflammation. However, documentation of such effects is, in most cases, only indicative. In the present study effects of two packages of functional feed ingredients commonly used in salmon production, were evaluated employing two inflammation models. One model employed soybean meal (SBM) as inducer of a severe inflammation, the other a mixture of corn gluten and pea meal (CoPea) inducing mild inflammation. The first model was used to evaluate effects of two packages of functional ingredients: P1 containing butyrate and arginine, and P2 containing ß-glucan, butyrate, and nucleotides. In the second model only the P2 package was tested. A high marine diet was included in the study as a control (Contr). The six diets were fed to salmon (average weight of 177g) in saltwater tanks (57 fish per tank), in triplicate, for 69 days (754 ddg). Feed intake was recorded. The growth rate of the fish was high, highest for the Contr (TGC: 3.9), lowest for SBM fed fish (TGC: 3.4). Fish fed the SBM diet showed severe symptoms of inflammation in the distal intestine as indicated by histological, biochemical, molecular, and physiological biomarkers. The number of differently expressed genes (DEG) between the SBM and Contr fed fish was 849 and comprised genes indicating alteration in immune functions, cellular and oxidative stress, and nutrient digestion, and transport functions. Neither P1 nor P2 altered the histological and functional symptoms of inflammation in the SBM fed fish importantly. Inclusion of P1 altered expression of 81 genes, inclusion of P2 altered 121 genes. Fish fed the CoPea diet showed minor signs of inflammation. Supplementation with P2 did not change these signs. Regarding composition of the microbiota in digesta from the distal intestine, clear differences regarding beta-diversity and taxonomy between Contr, SBM, and CoPea fed fish were observed. In the mucosa the microbiota differences were less clear. The two packages of functional ingredients altered microbiota composition of fish fed the SBM and the CoPea diet towards that of fish fed the Contr diet.

Dietary Fish Meal Level and a Package of Choline, ß-Glucan, and Nucleotides Modulate Gut Function, Microbiota, and Health in Atlantic Salmon (Salmo salar, L.).

Steatosis and inflammation have been common gut symptoms in Atlantic salmon fed plant rich diets. Choline has recently been identified as essential for salmon in seawater, and ß-glucan and nucleotides are frequently used to prevent inflammation. The study is aimed at documenting whether increased fishmeal (FM) levels (8 levels from 0 to 40%) and supplementation (Suppl) with a mixture of choline (3.0 g/kg), ß-glucan (0.5 g/kg), and nucleotides (0.5 g/kg) might reduce the symptoms. Salmon (186 g) were fed for 62 days in 16 saltwater tanks before samples were taken from 12 fish per tank for observation of biochemical, molecular, metabolome, and microbiome indicators of function and health. Steatosis but no inflammation was observed. Lipid digestibility increased and steatosis decreased with increasing FM levels and supplementation, seemingly related to choline level. Blood metabolites confirmed this picture. Genes in intestinal tissue affected by FM levels are mainly involved in metabolic and structural functions. Only a few are immune genes. The supplement reduced these FM effects. In gut digesta, increasing FM levels increased microbial richness and diversity, and changed the composition, but only for unsupplemented diets. An average choline requirement of 3.5 g/kg was indicated for Atlantic salmon at the present life stage and under the present condition.

Autologous Blood Patch Pleurodesis for the Management of a Persistent Air Leak after Secondary Spontaneous Pneumothorax.

Patients with secondary spontaneous pneumothorax (SSP) complicated by persistent air leak (PAL) and who are poor surgical candidates have limited treatment options. This case series explored autologous blood patch pleurodesis as a possible cost-effective management option. A total of 46 episodes of SSP with PAL were included. The procedure was successful in 33 (71.7%). Of these, 17 (51.5%) resolved within 1 day. The mean duration of intercostal drainage prior to the blood patch was 22 days in the successful group. Pneumothoraces with incomplete lung re-expansion at the time of procedure were successful in 20 of 30 (66.7%). Only human immunodeficiency virus infection was associated with failure (p = 0.03). Adverse events included transient fever (n = 3) that resolved spontaneously, and empyema (n = 3) which were successfully managed with antibiotics and pigtail drainage. We conclude that a large proportion of patients with SSP complicated by PAL who are unfit for surgery may be liberated from intercostal drainage by an autologous blood patch pleurodesis, with minimal adverse effects.

The Utility of Pleural Fluid Lactate Dehydrogenase to Adenosine Deaminase Ratio in Pleural Tuberculosis.

In high-burden settings, the diagnosis of pleural tuberculosis (TB) is frequently inferred in patients who present with lymphocyte predominant exudative effusions and high adenosine deaminase (ADA) levels. Two recent small retrospective studies suggested that the lactate dehydrogenase (LDH)/ADA ratio is significantly lower in TB than in non-TB pleural effusions and that the LDH/ADA ratio may be useful in differentiating pleural TB from other pleural exudates. We compared the pleural LDH/ADA ratios, ADA levels, and lymphocyte predominance of a prospectively collected cohort of patients with proven pleural TB (n = 160) to those with a definitive alternative diagnosis (n = 68). The mean pleural fluid LDH/ADA ratio was lower in patients with pleural TB than alternative diagnoses (6.2 vs. 34.3, p < 0.001). The area under the receiver operating characteristic curve was 0.92 (p < 0.001) for LDH/ADA ratio and 0.88 (p < 0.001) for an ADA ≥40 U/L alone. A ratio of ≤12.5 had the best overall diagnostic efficiency, while a ratio of ≤10 had a specificity of 90% and a positive predictive value of 95%, with a sensitivity of 78%, making it a clinically useful "rule in" value for pleural TB in high incidence settings. When comparing the LDH/ADA ratio to an ADA level ≥40 U/L in the presence of a lymphocyte predominant effusion, the latter performed better. When lymphocyte values are unavailable, our data suggest that the LDH/ADA ratio is valuable in distinguishing TB effusions from other pleural exudates.

Relative Sparing of the Left Upper Zone on Chest Radiography in Severe COVID-19 Pneumonia.

The radiological findings of COVID-19 are well-described, including its evolution. In an earlier report of admission chest radiographs of patients with COVID-19, we anecdotally noted relative sparing of the left upper zone (LUZ). We subsequently aimed to describe the main chest radiograph findings in another cohort, focusing on zonal predominance. The admission chest radiographs of 111 patients with CO-VID-19 pneumonia requiring intensive care admission were reviewed by 2 thoracic radiologists and categorized according to the predominant pattern into either ground-glass opacities (GGOs), alveolar infiltrates and/or consolidation, or reticular and/or nodular infiltrates or an equal combination of both, and the extent of disease involvement of each of the zones using a modified Radiologic Assessment of Lung Edema (RALE) score. Parenchymal changes were detected in all. In total, 106 radiographs showed GGOs, alveolar infiltrates, and/or consolidation, and 5 had a combination of reticular/nodular infiltrates as well as GGOs, alveolar infiltrates, and/or consolidation. The LUZ had a significant lower grading score than the right upper zone: 1 versus 2 (p < 0.001). Likewise, the upper zones had a significant lower score than the mid and lower zones (p < 0.001). Our findings confirmed the relative sparing of the LUZ in severe COVID-19 pneumonia.

Gut immune functions and health in Atlantic salmon (Salmo salar) from late freshwater stage until one year in seawater and effects of functional ingredients: A case study from a commercial sized research site in the Arctic region.

The present study was conducted to strengthen the knowledge on gut immune functions and health in Atlantic salmon under large scale, commercial conditions in the Arctic region of Norway. Two groups of fish were monitored, one fed a series of diets without functional ingredients (Ref) and the other diets with functional ingredients (Test). The nutritional composition of the two diet series varied in parallel according to the nutrient requirements of the fish during the observation time. The content of functional ingredients in the Test diets, i.e. nucleotides, yeast cell walls, a prebiotic and essential fatty acids, varied in accordance with a strategy developed by the feed company. The fish were observed at four sampling time points, the first (FW) in May 2016 two weeks before seawater transfer, the other three throughout the following seawater period until the fish reached a size of about 2 kg, i.e. in June, four weeks after seawater transfer (SW1); in November (SW2), and in April the following year (SW3). Gut health was assessed based on histopathological indicators of lipid malabsorption and gut inflammation, expression of gut immune, barrier and other health related genes, plasma biomarkers, somatic indices of intestinal sections, as well as biomarkers of digestive functions. Seawater transfer of the fish (SW1 compared to FW) caused a marked lowering of expression of genes related to immune and barrier functions in the distal intestine, i.e. cytokines (il1ß, il10, tgfß, ifnγ), T-cell markers (cd3γδ), myd88 and tight junction proteins (zo-1, claudin-15, claudin-25b), indicating suppressed immune and barrier functions. At SW2 and SW3, most of the immune biomarkers showed values similar to those observed at FW. The development of plasma cholesterol and triglyceride levels showed similar picture, with markedly lower levels after seawater transfer. Lipid malabsorption was observed in particular in fish from SW1 and SW2, as indicated by hyper-vacuolation of the pyloric caeca enterocytes with concurrently increased expression levels of plin2. Regarding effects of functional ingredients, significantly lower condition factor and plasma triglyceride level were observed for Test-fed fish at SW2, indicating a metabolic cost of use of a mixture of nucleotides, yeast cell walls and essential fatty acids. No clear effects of functional ingredients on expression of gut immune genes and other health indexes were observed through the observation period. The great, temporary lowering of expression of gut immune and barrier genes at SW1 is suggested to be an important factor underlying the increased vulnerability of the fish at this time point. Our findings regarding supplementation with functional ingredients raise questions whether some of these ingredients overall are beneficial or might come with a metabolic cost. Our results highlight the need for a better understanding of the cause and consequences of the suppression of gut immune functions of farmed Atlantic salmon just after seawater transfer, and the use of functional ingredients under commercial conditions.

Performance of LoRaWAN for Handling Telemetry and Alarm Messages in Industrial Applications.

This paper analyzes the feasibility of the coexistence of telemetry and alarm messages employing Long-Range Wide-Area Network (LoRaWAN) technology in industrial environments. The regular telemetry messages come from periodic measurements from the majority of sensors while the alarm messages come from sensors whose transmissions are triggered by rarer (random) events that require highly reliable communication. To reach such a strict requirement, we propose here strategies of allocation of spreading factor, by treating alarm and regular (telemetry) messages differently. The potential of such allocation strategies has also been investigated under retransmission and diversity of gateways. Both indoor industrial plant and open-field scenarios are investigated. We compare the proposed solution with a benchmark scenario-where no alarm is considered-by using system level simulation. Our results show that it is possible to achieve high reliability with reasonably low delay for the alarm messages without significantly affecting the performance of the regular links.

Maternal knowledge of effective breastfeeding and its benefits, as potential determinant of attitudes to infant feeding: A survey in Calabar, Nigeria.

Appropriate breastfeeding is a cost-effective child survival strategy. This study assessed relationship between knowledge of breastfeeding and attitude towards infant feeding among pregnant women in Calabar, Nigeria. By convenience sampling, consenting antenatal clinic attendees were recruited from secondary health centers in Calabar. Pre-tested questionnaire was used to assess knowledge of different aspects of breastfeeding, while the Iowa Infant Feeding Attitude Scale (IIFAS) was used to assess attitude towards infant feeding. Data was analyzed using SPSS version 21.0, with p-value of less than 0.05 considered statistically significant. Two hundred and fifty (250) pregnant women were surveyed with mean age of 29.7 ± 6.1 years. One hundred and eight respondents (43.2%) had unsatisfactory levels of knowledge. Common areas of misconception were oral thrush effect of breastfeeding (47.2%), frequency of breast milk expression (47.6%), and effects of inverted nipples (45.6%). Most respondents (92.0%) had neutral attitude to infant feeding, and there was no significant relationship between overall knowledge of breastfeeding and infant feeding attitude (p <0.05). Of all the knowledge areas assessed, only benefits to mothers (r=0.11, p=0.08) and effective breastfeeding (r=0.17, p=0.01), had knowledge scores that correlated positively with infant feeding attitude scores. These findings contribute to existing literature required for improvement in policies and strategies, for breastfeeding education and child survival, especially in resource-poor settings. There is need for further research towards improving priority content of maternal health education during the time-constrained ANC visits.

Gut health and vaccination response in pre-smolt Atlantic salmon (Salmo salar) fed black soldier fly (Hermetia illucens) larvae meal.

Limited availability of sustainable feed ingredients is a serious concern in salmon aquaculture. Insects may become an important, sustainable resource for expanding the raw material repertoire. Herein, we present data from an 8-week feeding trial with pre-smolt Atlantic salmon (initial body weight 49 ±â€¯1.5 g) fed either a reference diet containing fish meal, soy protein concentrate and wheat gluten as protein sources, or a test diet wherein 85% of the protein was supplied by black soldier fly larvae meal. Possible diet effect on the systemic immune response was evaluated by measuring plasma antibody titers after vaccination against infectious pancreatic necrosis virus (IPNV). The gut health of fish was evaluated using endpoints including organ and tissue indices, histopathological parameters and gene expression. Both diets induced the same level of antibody responses against IPNV. In fish fed the reference diet, the histological examination of the pyloric caeca mucosa showed clear hyper-vacuolization suggestive of lipid accumulation in enterocytes, whereas this was less pronounced in the insect meal fed fish. Expression of genes relevant to lipid metabolism confirmed these histological findings. Immune and barrier-function gene expression profiles were both generally not affected by diet. However, the fish fed insect meal showed increased expression of genes indicative of stress response, immune tolerance and increased detoxification activity. In summary, our results showed no indications that dietary inclusion of insect meal affected the gut health of Atlantic salmon negatively. The insect meal based diet seemed to reduce excessive lipid deposition in the pyloric caeca and stimulate xenobiotic metabolism.

Simple Anatomical Calculations Possibly As Accurate As Three-Dimensional Lobar Quantification with SPECT-CT in Predicting Lung Function after Pulmonary Resection.

The estimation of predicted postoperative (PPO) lung function is important in lung resection candidates. We utilized simple anatomical calculations and single-photon emission computed tomography combined with computed tomography (SPECT-CT) to calculate PPO in 24 consecutive patients with impaired pulmonary function who underwent lung resection. PPO values calculated by anatomical calculations and three-dimensional lobar SPECT-CT quantification both correlated well with the postoperative forced expiratory volume in 1 s, with r = 0.825, p < 0.001 and r = 0.796, p < 0.001, respectively. Both techniques fared well at predicting postoperative lung function, but our observations unexpectedly suggested that simple anatomical calculations might be equivalent to three-dimensional SPECT-CT lobar quantification.

A close nuclear black-hole pair in the spiral galaxy NGC 3393.

The current picture of galaxy evolution advocates co-evolution of galaxies and their nuclear massive black holes, through accretion and galactic merging. Pairs of quasars, each with a massive black hole at the centre of its galaxy, have separations of 6,000 to 300,000 light years (refs 2 and 3; 1 parsec = 3.26 light years) and exemplify the first stages of this gravitational interaction. The final stages of the black-hole merging process, through binary black holes and final collapse into a single black hole with gravitational wave emission, are consistent with the sub-light-year separation inferred from the optical spectra and light-variability of two such quasars. The double active nuclei of a few nearby galaxies with disrupted morphology and intense star formation (such as NGC 6240 with a separation of about 2,600 light years and Mrk 463 with a separation of about 13,000 light years between the nuclei) demonstrate the importance of major mergers of equal-mass spiral galaxies in this evolution; such mergers lead to an elliptical galaxy, as in the case of the double-radio-nucleus elliptical galaxy 0402+379 (with a separation of about 24 light years between the nuclei). Minor mergers of a spiral galaxy with a smaller companion should be a more common occurrence, evolving into spiral galaxies with active massive black-hole pairs, but have hitherto not been seen. Here we report the presence of two active massive black holes, separated by about 490 light years, in the Seyfert galaxy NGC 3393 (50 Mpc, about 160 million light years). The regular spiral morphology and predominantly old circum-nuclear stellar population of this galaxy, and the closeness of the black holes embedded in the bulge, provide a hitherto missing observational point to the study of galaxy/black hole evolution. Comparison of our observations with current theoretical models of mergers suggests that they are the result of minor merger evolution.

Endobronchial Valve Used as Salvage Therapy in a Mechanically Ventilated Patient with Intractable Life-Threatening Haemoptysis.

Treatment options for intractable life-threatening haemoptysis in mechanically ventilated patients with structural lung disease who do not respond to bronchial artery embolisation (BAE) and who are deemed unfit for surgery are limited. A 26-year-old HIV-positive male with a poorly preserved CD4 count and active pulmonary tuberculosis was intubated and mechanically ventilated for persistent life-threatening haemoptysis. Two attempts at BAE failed, and life-threatening haemoptysis recurred daily for 14 days despite antituberculous therapy. He was deemed unfit for surgery during that period. We proceeded to identify the source of bleeding endoscopically and implanted an endobronchial valve in the left upper lobe bronchus. Following the collapse of the affected lobe, haemoptysis ceased and the patient was promptly liberated from mechanical ventilation. He remained haemoptysis free for the duration of his hospitalisation. Endobronchial valves, therefore, may be a viable option in patients mechanically ventilated with persistent life-threatening haemoptysis in whom all other conventional measures fail and who are considered unfit for surgery.

Determination of DNA adducts by combining acid-catalyzed hydrolysis and chromatographic analysis of the carcinogen-modified nucleobases.

The commonly used method of analyzing carcinogen-induced DNA adducts involves the hydrolysis of carcinogen-modified DNA samples by using a mixture of enzymes, followed by (32)P-postlabeling or liquid chromatography (LC)-based analyses of carcinogen-modified mononucleotides/nucleosides. In the present study, we report the development and application of a new approach to DNA adduct analysis by combining the H(+)/heat-catalyzed release of carcinogen-modified nucleobases and the use of LC-based methods to analyze DNA adducts. Results showed that heating the carcinogen-modified DNA samples at 70 °C for an extended period of 4 to 6 h in the presence of 0.05% HCl can efficiently induce DNA depurination, releasing the intact carcinogen-modified nucleobases for LC analyses. After optimizing the hydrolysis conditions, DNA samples with C8- and N (2) -modified 2'-deoxyguanosine, as well as N (6) -modified 2'-deoxyadenosine, were synthesized by reacting DNA with 1-nitropyrene, acetaldehyde, and aristolochic acids, respectively. These samples were then hydrolyzed, and the released nucleobase adducts were analyzed using LC-based analytical methods. Analysis results demonstrated a dose-dependent release of target DNA adducts from carcinogen-modified DNA samples, indicating that the developed H(+)/heat-catalyzed hydrolysis method was quantitative. Comparative studies with enzymatic digestion method on carcinogen-modified DNA samples revealed that the two hydrolysis methods did not yield systematically different results.

Can Large Hydatid Cysts Resolve with Medical Treatment Alone?

A 66-year-old female from a rural area in South Africa presented with non-life-threatening haemoptysis. Radiologic and serological investigations attributed her symptoms to bilateral, large echinococcal cysts. She declined surgery despite her lung physiologic parameters, which deemed her eligible. Medical therapy with oral albendazole was initiated with excellent clinical and radiologic response during a follow-up period of 18 months. To our knowledge, this is one of the first reported cases in the literature that shows complete resolution of bilateral large echinococcal cysts with medical treatment alone in an adult patient.

Comparison of DNA and RNA Adduct Formation: Significantly Higher Levels of RNA than DNA Modifications in the Internal Organs of Aristolochic Acid-Dosed Rats.

Prolonged exposure to aristolochic acid (AA)contaminated slimming drugs and food is believed to be associated with the development of endemic nephropathy in Belgian women and in farmers living alongside the Danube River. Decades of research has revealed the pathophysiology of carcinogenesis of AA,and the molecular mechanisms underlying renal interstitial fibrosis remain unclear. We hypothesized that RNA modification may have contributed to the observed toxicity of AA. Thus, a highly sensitive and selective ultra-high performance liquid chromatography-coupled tandem mass spectrometric method was developed to quantify RNA-AA adducts in target and nontarget organs of AA-dosed rats. The results revealed, for the first time, that AA forms RNA adducts in vitro and in vivo. Comparative studies on DNA revealed that RNA is modified by AA at frequencies approximately 6-fold higher than that of DNA in both kidney and liver tissue in AA-dosed rats. Results also demonstrated that guanosine is modified by AA at frequencies significantly higher than that of adenosine, 2-deoxyadenosine, and 2-deoxyguanosinein both organs of the AA-dosed. This finding suggests that guanosine is a major target for AA and that guanosine adducts of AA might be critical lesions in the pathophysiology of AA-induced toxicity. It is anticipated that the results of our study may open up a new area of investigating the nephrotoxicity and/or carcinogenicity by quantifying RNA adducts using the UPLC-MS/MS technique of high sensitivity and selectivity.

Quantification of aristolochic acid-RNA adducts in the urine of aristolochic acid-treated rats by liquid chromatography-tandem mass spectrometry.

Balkan endemic nephropathy (BEN) is a peculiar renal disease affecting thousands of farmers living in the suburban areas of the Balkan countries. Emerging evidence suggested that BEN is an environmental disease caused by chronic food poisoning with aristolochic acid (AA). We have developed a sensitive liquid chromatography-tandem mass spectrometry method to detect urinary RNA-AA adducts. Results revealed high levels of RNA-AA adducts in the urine samples collected from AA-treated rats. To the best of our knowledge, this study is the first to report on the detection of urinary RNA-AA adducts. Compared with previous studies that quantified DNA-AA adducts, this method is more sensitive and user-friendly.

The utility of Xpert MTB/RIF performed on bronchial washings obtained in patients with suspected pulmonary tuberculosis in a high prevalence setting.

BACKGROUND: Xpert MTB/RIF has been shown to have a superior sensitivity to microscopy for acid fast bacilli (AFB) in sputum and has been recommended as a standard first line investigation for pulmonary tuberculosis (PTB). Bronchoscopy is a valuable tool in diagnosing PTB in sputum negative patients. There is limited data on the utility of Xpert MTB/RIF performed on bronchial lavage specimens. Our aim was to evaluate the diagnostic efficiency of Xpert MTB/RIF performed on bronchial washings in sputum scarce/negative patients with suspected PTB. METHODS: All patients with a clinical and radiological suspicion of PTB who underwent bronchoscopy between January 2013 and April 2014 were included. The diagnostic efficiencies of Xpert MTB/RIF and microscopy for AFB were compared to culture for Mycobacterium tuberculosis. RESULTS: Thirty nine of 112 patients were diagnosed with culture-positive PTB. Xpert MTB/RIF was positive in 36/39 with a sensitivity of 92.3% (95% CI 78-98%) for PTB, which was superior to that of smear microscopy (41%; 95% CI 26.0-57.8%, p = 0.005). The specificities of Xpert MTB/RIF and smear microscopy were 87.7% (95% CI 77.4-93.9%) and 98.6% (95% CI 91.6%-99.9%) respectively. Xpert MTB/RIF had a positive predictive value of 80% (95% CI; 65-89.9%) and negative predictive value of 95.5% (95% CI 86.6-98.8%). 3/9 patients with Xpert MTB/RIF positive culture negative results were treated for PTB based on clinical and radiological findings. CONCLUSION: Xpert MTB/RIF has a higher sensitivity than smear microscopy and similar specificity for the immediate confirmation of PTB in specimens obtained by bronchial washing, and should be utilised in patients with a high suspicion of pulmonary tuberculosis.

A novel reversed-phase HPLC method for the determination of urinary creatinine by pre-column derivatization with ethyl chloroformate: comparative studies with the standard Jaffé and isotope-dilution mass spectrometric assays.

Creatinine is an important biomarker for renal function diagnosis and normalizing variations in urinary drug/metabolites concentration. Quantification of creatinine in biological fluids such as urine and plasma is important for clinical diagnosis as well as in biomonitoring programs and urinary metabolomics/metabonomics research. Current methods for creatinine determination either are nonselective or involve the use of expensive mass spectrometers. In this paper, a novel reversed-phase high-performance liquid chromatographic (HPLC) method for the determination of creatinine of high hydrophilicity by pre-column derivatization with ethyl chloroformate is presented. N-Ethyloxycarbonylation of creatinine significantly enhanced the hydrophobicity of creatinine, facilitating its chromatographic retention as well as quantification by HPLC. Factors governing the derivatization reaction were studied and optimized. The developed method was validated and applied for the determination of creatinine in rat urine samples. Comparative studies with isotope-dilution mass spectrometric method revealed that the two methods do not yield systematic differences in creatinine concentrations, indicating the HPLC method is suitable for the determination of creatinine in urine samples.