Variations in Helicobacter pylori lipopolysaccharide to evade the innate immune component surfactant protein D

Helicobacter pylori is a common and persistent human pathogen of the gastric mucosa. Surfactant protein D (SP-D), a component of innate immunity, is expressed in the human gastric mucosa and is capable of aggregating H. pylori. Wide variation in the SP-D binding affinity to H. pylori has been observed in clinical isolates and laboratory-adapted strains. The aim of this study was to reveal potential mechanisms responsible for evading SP-D binding and establishing persistent infection. An escape variant, J178V, was generated in vitro, and the lipopolysaccharide (LPS) structure of the variant was compared to that of the parental strain, J178. The genetic basis for structural variation was explored by sequencing LPS biosynthesis genes. SP-D binding to clinical isolates was demonstrated by fluorescence-activated cell sorter analyses. Here, we show that H. pylori evades SP-D binding through phase variation in lipopolysaccharide. This phenomenon is linked to changes in the fucosylation of the O chain, which was concomitant with slipped-strand mispairing in a poly(C) tract of the fucosyltransferase A (fucT1) gene. SP-D binding organisms are predominant in mucus in vivo (P = 0.02), suggesting that SP-D facilitates physical elimination. Phase variation to evade SP-D contributes to the persistence of this common gastric pathogen.     

Correlation of optic nerve sheath diameter measurements by computed tomography and magnetic resonance imaging

BackgroundTraditionally, intracranial pressure is measured by direct ventriculostomy, which is invasive. Noninvasive measures such as bedside ultrasound and magnetic resonance imaging have been advocated and utilized recently to assess the intracranial pressure. The role of this study is to determine the degree of agreement between measurements of the optic nerve sheath diameter by computed tomography (CT) and magnetic resonance imaging (MRI).Materials and MethodsRetrospective chart review of 100 consecutive patients who had both MRI and CT scan of the head from January 1, 2011, until March 31, 2013, at our center was performed. A discrepancy of 0.2 mm between the 2 measurements was set as acceptable difference. The measurements of optic nerve sheath diameter (ONSD) were compared for agreement between the 2 modalities using the method by Bland and Altman.ResultsA total of 100 patients with both MRI and CT scan of the head were selected. Of these 100 patients, 24 were male and 76 were female. The average age was 63 years. No ONSD abnormality was detected in any of the patients. The discrepancy in measurements of the ONSD between CT and MRI in transverse plane was less than the predetermined cut-off value of 0.2 mm. Within-subject variance was estimated at 0.0058 for both CT and MRI.ConclusionComparable results without significant discrepancy as predetermined by the study groups were obtained from CT scan. Measurement of ONSD by CT scan can be used to indirectly asses the intracranial pressure in addition to clinical assessment and other signs of increased intracranial pressure on CT scan.     

Real time optic nerve sheath diameter measurement during lumbar puncture

Measurement of optic nerve sheath diameter (ONSD) using point of care ultrasound has been used to indirectly assess the intracranial pressure (ICP) particularly in conditions where it is raised. Direct pressure measurements using probes reaching the ventricle system correlated with ONSD using ultrasound. Attempts were made to measure the ONSD pre and post lumbar puncture (LP) after draining cerebrospinal fluid (CSF) as well as post ventricular shunt placement. We report ONSD measurement and demonstrate dynamic changes during LP in a patient with known idiopathic intracranial hypertension (IIH).     

Effects of acrylic resin monomers on porcine coronary artery reactivity

The purpose of the present investigation was to assess the reactivity of porcine coronary arteries under in vitro conditions following their exposure to methyl methacrylate (MMA) and hydroxyethyl methacrylate (HEMA) monomers. Confirming previous studies using rat aortas, both MMA and HEMA induced acute/direct relaxation of coronary ring preparations, which was partly dependent on the endothelium. With prolonged tissue exposure, both monomers caused time- and concentration-dependent inhibition of receptor-mediated contraction of the vascular smooth muscle caused by prostaglandin F_2∝ (PGF_2∝), with HEMA causing more inhibition than MMA. Hydroxyethyl methacrylate, but not MMA, also produced impairment of non-receptor-mediated contraction of the coronary smooth muscle induced by KCl. On the other hand, neither HEMA nor MMA altered relaxation of the smooth muscle produced by the direct-acting pharmacological agent, sodium nitroprusside (SNP). While exposure to HEMA impaired endothelium-dependent vasorelaxation caused by bradykinin (BK), MMA markedly enhanced this endothelial-mediated response of the arteries. The enhanced endothelial response produced by MMA was linked to nitric oxide (NO) release. In conclusion, with prolonged tissue exposure, MMA causes less pronounced effects/adverse consequences on coronary smooth muscle function relative to the effect of HEMA, while enhancing vasorelaxation associated with release of NO from the endothelium. Accordingly, MMA-containing resin materials appear to be safer for human applications than materials containing HEMA.     

Effect of a thrombin receptor (protease-activated receptor 1, PAR-1) gene polymorphism in chronic hepatitis C liver fibrosis

Background and Aim:  Tissue injury leads to activation of coagulation and generation of thrombin. Inhibition of thrombin receptor protease-activated receptor 1 (PAR-1) has been shown to reduce liver fibrosis in animals. This study aimed to evaluate the effect of PAR-1 gene polymorphism on rate of liver fibrosis (RF) in chronic hepatitis C.
Methods:  Polymorphisms studied: C > T transition 1426 bp upstream of translation start site (-1426C/T), 13 bp repeat of preceding -506 5'-CGGCCGCGGGAAG-3' sequence (-506I/D), and A > T transversion in intervening sequence (IVS) 14 bp upstream of exon-2 start site (IVS-14A/T). A total of 287 European and 90 Brazilian patients were studied.
Results:  1426C/T polymorphism: There was a trend to higher RF in patients with the TT genotype ( P  = 0.06) and an association between genotype CC and slow fibrosis ( P  = 0.03) in Europeans. In males, RF was significantly higher in those with the TT genotype compared to CT ( P  = 0.003) and CC ( P  = 0.007). There was a significant association between TT and fast fibrosis ( P  = 0.04). This was confirmed in an independent cohort of Brazilians where RF was higher in TT than in CC ( P  = 0.03). Analysis of -506I/D showed no difference in RF and distribution of slow/fast fibrosis among different genotypes in both populations. Analysis of IVS-14A/T showed no difference between genotypes.
Conclusion:  In conclusion, these findings suggest that PAR-1 receptor polymorphisms influence the progression of liver fibrosis.     

Patient referral alone is not an effective strategy to capture partners of patients with sexually transmitted infections in low-resource settings: a case-control study

Aim

Partner notification (PN) is a key public health intervention aimed at preventing re-infection and controlling the spread of STIs. However, only limited research has been conducted to investigate factors associated with PN in Ethiopia.

Subject and methods

A nested case-control study was undertaken within a cohort of individuals being treated for STIs in public health facilities in Ethiopia. Hierarchical binary logistic regression was used to identify socio-demographic, behavioral and psychosocial factors associated with PN.

Results

A total of 250 patients on STI treatment who notified their partners (cases) were compared with 185 patients who did not notify their partners (controls). STI patients were less likely to notify their partner if they were single [AOR = 0.33, 95% CI: (0.15–0.73)], in a casual partnership [adjusted odds ratio (AOR) = 0.33, 95% CI: (0.15–73)], not knowledgeable about a partner’s sexual behavior [AOR = 0.43, 95% CI: (0.24–0.77)], had poor knowledge of risky sexual behavior [AOR = 0.23, 95% CI: (0.12–0.43)] and had no intention of notifying partners [AOR = 0.19, 95% CI: (0.10–0.36)]. The odds of PN were higher among highly educated respondents [AOR = 5.16; 95% CI: (1.83–14.54)].

Conclusion

Capturing STI cases through patient referral partner notification is less likely to be successful among patients who are single and in a casual relationship.

     

Do adult patients with diabetes mellitus living in rural part of Ethiopia and having poor social support have disproportionately poor self-care practice? A systematic review and meta-analysis

ObjectiveThis systematic review and meta-analysis is aimed at determining the pooled national percentage of diabetic self-care practice and its determinants among adult diabetic patients in Ethiopian.MethodsDifferent electronic databases including PubMed/Medline and search engines such as Google scholar were used to retrieve published studies. The Joanna Briggs Institute quality appraisal checklists were used to appraise the quality of studies. Data were extracted using excel spreadsheets and analyses were done by STATA 14. Heterogeneity among studies was diagnosed using the I² test. The DerSimonian and Laird random-effects model was employed for substantial heterogeneity (I2 > 50%). The pooled estimate of diabetic self-care and odds ratio was reported based on the 95% CI.ResultsA total of 3861 studies were identified, of which only 19 studies have reached the final qualitative synthesis and quantitative analysis. Well over half of the Ethiopian diabetic patients have good self-care 54.04% (47.07–61.01, I² = 97.3, P < 0.001). Subgroup analysis by region showed that the highest pooled estimate was observed in Southern Nations Nationalities and Peoples 81.96% (71.85–92.04), I² = 89.1, p < 0.002), whereas the lowest was from the Harari region 44.53% (32.16–56.89%) I² = 94%, p < 0.001). Being knowledgeable about diabetes Mellitus 2.69 (1.62, 4.46; I2 = 99%, p < 0.001), having good social support 2.25 (1.49–3.39; I² = 99%, p = 0.00), owning private glucometer 3.04(1.64, 5.65; I² = 97.4, P < 0.001), and being urban residents 3.26 (2.24, 4.74; I² = 96.3%, P < 0.001) promote diabetic victims to apply self-care practice.ConclusionsDespite the life-threatening complications of diabetes Mellitus, the percentage of patients applying self-care has remained low in Ethiopia, depicting the high proportion of diabetic patients are prone to develop long and short-term sequelae of diabetes Mellitus. Therefore, improving the client’s awareness about the disease and counseling clients about the significance of social support are believed to be possible strategies to improve self-care practice and policymakers are strongly recommended to combat complications to attain sustainable development goal 3.4 Aims to reduce premature death.RegistrationThe protocol has been registered under the prospective Register of Systematic Review and Meta-analysis (PROSPERO) and received a unique registration number CRD42020151014.