Intestinal Fatty Acid-Binding Protein as a Diagnostic Marker for Complicated and Uncomplicated Necrotizing Enterocolitis: A Prospective Cohort Study

Background

Early NEC symptoms are non-specific and diagnostic tests lack discriminative power. Intestinal fatty acid-binding protein (I-FABP), mainly located in small bowel enterocytes, is released into the blood following NEC-associated enterocyte disruption. Aim of this prospective cohort trial was to determine the diagnostic value of I-FABP measured in plasma (I-FABPp) and urine (I-FABPu) for the presence of NEC, to evaluate I-FABP levels during NEC development, and to assess its prognostic value for the progression from suspected to complicated disease.

Methods

Between 2010 and 2012 we prospectively enrolled neonates with suspected NEC. We measured I-FABP levels eight-hourly from onset of suspected NEC for at least 48 hours, or until surgery. NEC diagnosis was confirmed radiologically or during operation. We defined NEC as complicated if it resulted in surgery and/or death. We determined disease course and diagnostic I-FABP cut-off points.

Results

The study comprised 37 neonates (24M, 13F), gestational age 28 (24–36) weeks, birth weight 1190 (570–2,400) grams. We found significantly higher I-FABPp and I-FABPu levels in NEC patients (n = 22) than in patients with other diagnoses (n = 15). Cut-off values for diagnosing NEC were 9 ng/mL I-FABPp and 218 ng/mL I-FABPu, with corresponding likelihood ratios (LRs) of 5.6 (95% CI 0.89–35) and 5.1 (95% CI 0.73–36), respectively. I-FABP levels were highest in the first eight hours after symptom onset and gradually decreased over time. Cut-off values for complicated disease were 19 ng/mL I-FABPp and 232 ng/mL I-FABPu, with LRs of 10 (95% CI 1.6–70) and 11 (95% CI 1.6–81), respectively.

Conclusions

Both plasma and urinary I-FABP levels specifically identify NEC in preterm infants prior to appearance of diagnostic radiological signs suggestive for NEC. Moreover, serial I-FABP measurements accurately predict development of complicated disease.     

General practitioner reported incidence of Lyme carditis in the Netherlands

Background

Between 1994 and 2009, incidence rates of general practitioner (GP) consultations for tick bites and erythema migrans, the most common early manifestation of Lyme borreliosis, have increased substantially in the Netherlands. The current article aims to estimate and validate the incidence of GP-reported Lyme carditis in the Netherlands.

Methods

We sent a questionnaire to all GPs in the Netherlands on clinical diagnoses of Lyme borreliosis in 2009 and 2010. To validate and adjust the obtained incidence rate, medical records of cases of Lyme carditis reported by GPs in this incidence survey were reviewed and categorised according to likelihood of the diagnosis of Lyme carditis.

Results

Lyme carditis occurred in 0.2 % of all patients with GP-reported Lyme borreliosis. The adjusted annual incidence was six GP-reported cases of Lyme carditis per 10 million inhabitants, i.e. approximately ten cases per year in 2009 and 2010.

Conclusions

We report the first incidence estimate for Lyme carditis in the Netherlands, validated by a systematic review of the medical records. Although Lyme carditis is an uncommon manifestation of Lyme borreliosis, physicians need to be aware of this diagnosis, in particular in countries where the incidence of Lyme borreliosis has increased during the past decades.     

The identification of biomarkers differentiating Mycobacterium tuberculosis and non-tuberculous mycobacteria via thermally assisted hydrolysis and methylation gas chromatography–mass spectrometry and chemometrics

Infections with non-tuberculous mycobacteria (NTM) are increasing, particularly among immune-compromised patients and those with damaged lungs. Mycobacterium tuberculosis complex (MTB) strains, however, remain the most common cause of mycobacterial infection. A rapid method of distinguishing MTB from NTM is required for correct diagnosis and tuberculosis management. We have developed an automated procedure based on thermally-assisted hydrolysis and methylation followed by gas chromatography–mass spectrometry (THM–GC–MS) and advanced chemometrics to differentiate MTB from NTM. We used early cultures of mycobacteria in this first step towards the direct identification of these bacteria in sputum using a hand-held portable device. To build a classification model, we used 44 strains including 15 MTB and 29 NTM. A matrix of the aligned dataset containing ~45,700 features (retention time/mass pairs) for the 44 observations was submitted to partial least squares discriminant analysis (PLS–DA). We could reduce the number of features down to 250 without compromising the accuracy of the model. Twenty different compounds were found through mass spectral interpretation of these 250 features. Some of these compounds have not been linked to tuberculosis before, others have been proposed previously as diagnostic biomarkers for this disease. We have built a final model based on our proposed biomarkers that performed with 95 % accuracy in distinguishing MTB from NTM in early cultures. Since all these biomarkers have been chemically identified, work can proceed towards the development of simpler, bed-side diagnostic tests to differentiate MTB from NTM in sputum.     

Coordinated multidisciplinary care for ambulatory Huntington's disease patients. Evaluation of 18 months of implementation

Background

terminal deletions of the distal portion of the short arm of chromosome 3 cause a rare contiguous gene disorder characterized by growth retardation, developmental delay, mental retardation, dysmorphisms, microcephaly and ptosis. The phenotype of individuals with deletions varies from normal to severe. It was suggested that a 1,5 Mb minimal terminal deletion including the two genes CRBN and CNTN4 is sufficient to cause the syndrome. In addition the CHL1 gene, mapping at 3p26.3 distally to CRBN and CNTN4, was proposed as candidate gene for a non specific mental retardation because of its high level of expression in the brain.

Methods and Results

we describe two affected siblings in which array-CGH analysis disclosed an identical discontinuous terminal 3p26.3 deletion spanning less than 1 Mb. The deletion was transmitted from their normal father and included only the CHL1 gene. The two brothers present microcephaly, light mental retardation, learning and language difficulties but not the typical phenotype manifestations described in 3p- syndrome.

Conclusion

a terminal 3p26.3 deletion including only the CHL1 gene is a very rare finding previously reported only in one family. The phenotype of the affected individuals in the two families is very similar and the deletion has been inherited from an apparently normal parent. As already described for others recurrent syndromes with variable phenotype, these findings are challenging in genetic counselling because of an evident variable penetrance.     

Gloeobacter Rhodopsin,Limitation of Proton Pumping at High Electrochemical Load

We studied the photocurrents of a cyanobacterial rhodopsin Gloeobacter violaceus (GR) in Xenopus laevis oocytes and HEK-293 cells. This protein is a light-driven proton pump with striking similarities to marine proteorhodopsins, including the D121-H87 cluster of the retinal Schiff base counterion and a glutamate at position 132 that acts as a proton donor for chromophore reprotonation during the photocycle. Interestingly, at low extracellular pH_o and negative voltage, the proton flux inverted and directed inward. Using electrophysiological measurements of wild-type and mutant GR, we demonstrate that the electrochemical gradient limits outward-directed proton pumping and converts it into a purely passive proton influx. This conclusion contradicts the contemporary paradigm that at low pH, proteorhodopsins actively transport H⁺ into cells. We identified E132 and S77 as key residues that allow inward directed diffusion. Substitution of E132 with aspartate or S77 with either alanine or cysteine abolished the inward-directed current almost completely. The proton influx is likely caused by the pK_a of E132 in GR, which is lower than that of other microbial ion pumping rhodopsins. The advantage of such a low pK_a is an acceleration of the photocycle and high pump turnover at high light intensities.     

Identification and expression analysis of a new glycoside hydrolase family 55 exo-β-1,3-glucanase-encoding gene in Volvariella volvacea suggests a role in fruiting body development

The edible straw mushroom Volvariella volvacea is an important crop in South East Asia and is predominantly harvested in the egg stage. Rapid stipe elongation and cap expansion result in a swift transition from the egg to elongation and maturation stage, which are subjected to fast senescence and deterioration. In other mushrooms, β-1,3-glucanases have been associated with degradation (softening) of the cell wall during stipe elongation and senescence. We present a new glycoside hydrolase family 55 (GH55) exo-β-1,3-glucanase gene, exg2, and highly conserved deduced EXG2 protein. The 3D model and presumed catalytic residues of V. volvacea EXG2 are identical to Lentinula edodes EXG2 and Phanerochaete chrysosporium Lam55A, supporting similar enzymatic functions. In addition to previous association to stipe elongation and senescence, our data clearly indicates a role for cap (pileus) expansion. Digital gene expression, quantitative PCR and isobaric tags for relative and absolute quantification analysis showed low exg2 and EXG2 levels in primordia, button, egg and elongation stages and significantly increased levels in the maturation stage. Subsequent relative quantitative PCR analysis designated expression of exg2 to the stipe in the elongation stage and to the pileus and stipe in the maturation stage. EXG2 cell wall softening activity, close correlation of exg2 expression with the principal expanding mushroom tissues and a strong conservation of expression patterns and protein sequences in other mushrooms, make V. volvacea exg2 an important candidate for future studies on mechanisms of fruiting body expansion and senescence causing commodity value loss.