Neuraminidase produces dose-dependent decrease of slime production and adherence of slime-forming, coagulase-negative staphylococci

BACKGROUND: Slime is one of the important structures of certain bacterial strains involved in nonspecific adherence. This study was conducted to determine the role of neuraminidase on slime formation and adherence of slime-forming coagulase-negative staphylococci to inert surface. METHODS: Quantitative biofilm and qualitative bacterial adherence assays were performed with increasing concentrations of neuraminidase extracted from Clostridium perfringens-treated bacteria in polystyrene plates and polypropylene tubes. RESULTS: Slime production of slime-forming, coagulase-negative staphylococci was significantly decreased dose dependently at > or =100 mU/mL (p <0.001). Bacterial adherence to smooth surface was impeded at > or =100 mU/mL of neuraminidase treatment and adherence results were comparable with slime production assay results. CONCLUSIONS: Sialic acid may be a constituent molecule of slime and involved in bacterial adherence to inert surface. These results represent new insight into the mechanism of slime production and adherence of slime-forming, coagulase-negative staphylococci to inert surface.     

Hepatitis A and B seropositivity among medical students

OBJECTIVE: Health science students are commonly exposed to some infectious agents, including hepatitis A virus (HAV) and hepatitis B virus (HBV), which may cause substantial morbidity and even deaths. The identification of prevalence and risk factors is essential for implementing efficacious preventive measures. A serological survey was performed among medical students of Adnan Menderes University Medical Faculty to determine the prevalence of antibodies against HAV and HBV, and, as a secondary objective, to determine risk factors for acquisition of these infections. METHODS: Nearly all students were included in the study. All participants completed a structured questionnaire that assessed demographic and socio-economic characteristics. Anti-HAV IgG, anti-HBc IgG, HbsAg and anti-HBs were tested using commercially available Elisa kits. RESULTS: A total of 247 students, 146 (59.1%) male and 101 (40.9%) female, were included in the study. The prevalence of anti-HAV IgG was detected as 64%. Number of siblings and place of residence were detected as independent factors affecting the anti-HAV seropositivity. The prevalence of anti-HBc IgG was detected as 7.3%. Among the students positive for anti-HBc IgG, 5 (2%) students were HBsAg positive and the other 13 (5.3%) were anti-HBs positive. HBV infection in household members, risky sexual behaviour and vaccination were independent factors affecting the prevalence of anti-HBc IgG positivity. CONCLUSIONS: The high susceptibility of medical students and their increased risk of clinical HAV and HBV infection identify a need for primary prevention through the administration of vaccination in this group in western Turkey.     

Familial cardioneuromyopathy with hyaline masses and nemaline rods: a novel phenotype

Two siblings (patients 1 and 2) had adult-onset muscle weakness that was greater distally than proximally, as well as respiratory insufficiency, cardiomyopathy, and cervical spine anomalies. Electromyography studies indicated myopathy and findings consistent with neuropathy in both. In the deltoid muscle of patient 1 and the anterior tibial muscle of patient 2, myriad type 1 fibers harbored large, irregularly polygonal, and mostly central hyaline masses, small vacuoles, and nemaline rods flanking the hyaline masses or congregated under the sarcolemma. The hyaline masses are intensely congophilic; react strongly for desmin, alphaB-crystallin, alpha1-antichymotrypsin, and ubiquitin and variably for gelsolin and dystrophin; and are devoid of alpha-actinin, nebulin, titin, and slow myosin. The presence of ubiquitin, gelsolin, and fragmented filaments, and the absence of nebulin, titin, alpha-actinin, and slow myosin in the hyaline masses, signal nonlysosomal protein degradation. Ultrastructurally, the hyaline masses are composed of intermediate-density amorphous material intermingled with fragmented filaments and irregularly branching, pleomorphic, highly electron-dense material, resembling the hyaline structures of myofibrillar myopathy. We conclude that the pathological process in this syndrome is one that induces destruction of myofibrillar components, resulting in aggregation of the degraded residues in hyaline masses, and causes replication of Z disks, resulting in formation of nemaline rods.     

Myopathy with muscle spindle excess: A new congenital neuromuscular syndrome?

An infant presented with congenital weakness, hypotonia, arthrogryposis, atrial tachycardia, and a left intra-abdominal neuroblastoma. Muscle biopsy revealed marked excess of muscle spindles with atrophy of extrafusal fibers. The patient expired at age 14 months from progressive cardiorespiratory failure. Postmortem examination demonstrated muscle-spindle excess in other muscles, along with hypertrophic obstructive cardiomyopathy and organomegaly. Muscle spindle excess has previously been reported in two patients with Noonan syndrome and progressive hypertrophic cardiomyopathy. Muscle spindle excess with hypertrophic cardiomyopathy, organomegaly, and, possibly, congenital neuroblastoma suggests a syndromic association and may represent an unusual form of congenital myopathy.     

The Effect of Stent Cell Geometry on Carotid Stenting Outcomes

Purpose

The aim of this study was to investigate the effect of stent cell geometry on midterm results of carotid artery stenting (CAS).

Materials and Method

One hundred fifty-five patients underwent CAS between February 2010 and December 2012. Ninety-one open- and 84 closed-cell stents were used in this non-randomized, retrospective study. Periprocedural complications were defined as the ones happened during the procedure or within 30 days afterwards. Starting from the 6th month after the procedure, in-stent restenosis was detected with multidetector computed tomography angiography and classified into four groups from focal restenosis to occlusion.

Results

Eleven complications were encountered in the periprocedural period (four on the open- and seven on the closed-cell group). Total complication rate was 6.3 % (11/175). No significant difference was detected in terms of periprocedural complications between two groups (p = 0.643). There was statistically significant difference between stent design groups in regard to radiological findings (p = 0.002). Sixteen of open-cell stents and three of closed-cell stents had focal restenosis. One closed-cell stent had diffuse proliferative restenosis and one open-cell stent had total occlusion.

Conclusion

In-stent restenosis was more common in open-cell stent group, which have larger free cell area than closed-cell stents. Although our radiologic findings promote us to use closed-cell design if ‘possible’, no difference was detected in terms of clinical outcomes.

     

The effect of N-methyl-D-aspartate receptor antagonist (memantine) on esophageal and gastric smooth muscle: functional investigation in a rat hydrocephalus model

Object

The purpose of this study was to investigate the effect of N-methyl-d-aspartate (NMDA) receptor antagonist on esophageal and gastric smooth muscle reactivity in a rat hydrocephalus model.

Material and Methods

Hydrocephalus was induced in rats by injection of kaolin into the cisterna magna. Two weeks after the procedure, memantine (20 mg/kg per day, 2 weeks) was given to rats with hydrocephalus in the memantine group (MG). The rest of the rats with hydrocephalus received serum physiologic (hydrocephalus group, HG). The control group (nonhydrocephalic rats, CG) was sham operated. The fourth group consisted of nonhydrocephalic rats with treated memantine (memantine control group, MC). Contractile (KCl, carbachol) and relaxant (isoprenaline, papaverine) esophageal and gastric smooth muscle reactivity were determined by in vitro muscle technique.

Results

No significant difference was found in the KCl (nonreceptor-mediated)-induced esophageal smooth muscle reactivity among the groups. Carbachol (receptor-mediated)-induced smooth muscle reactivity significantly decreased in HG compared to other groups. The isoprenaline (receptor-mediated)-induced smooth muscle reactivity significantly decreased in HG compared to other groups. No significant difference was found in smooth muscle reactivity to papaverine (nonreceptor-mediated) among the groups.Gastric smooth muscle reactivity to KCl significantly increased in HG compared to other groups. Also, KCl-induced smooth muscle reactivity significantly increased in MG compared to CG and MC. Carbachol-induced smooth muscle reactivity significantly decreased in HG compared to MG, CG, and MC. No significant difference was observed in isoprenaline- and papaverine-induced smooth muscle reactivity among the groups.

Conclusion

Our findings suggest that memantine may influence esophageal and gastric smooth muscle reactivity in hydrocephalus.     

Comparative assessment of subjective image quality of cross-sectional cone-beam computed tomography scans

Since the introduction of cone-beam computed tomography (CBCT), several novel systems with different technical specifications and settings have become commercially available. Therefore, it is essential to evaluate CBCT systems for differences in the subjective quality of images obtained for various dental procedures. We evaluated the subjective image quality of cross-sectional scans obtained from various CBCT systems. Images of three cadaver mandibles were obtained from four different CBCT units: 1) Veraviewepocs 3D 40 × 40 mm field of view (FOV) (voxel size: 0.125 × 0.125 × 0.125 mm), 2) Iluma, low-resolution (voxel size: 0.3 × 0.3 × 0.3 mm), 3) Kodak, 50 × 3.7 cm FOV (voxel size: 0.076 × 0.076 × 0.076 mm), and 4) Vatech 12 × 8.5cm FOV (voxel size: 0.160 × 0.160 × 0.160 mm). We assessed subjective image quality and the visibility of 10 specific features, namely, caries, amalgam restoration, final implant drill, root canal filling, metal crown, mandibular canal, mental foramen, tooth (periodontal ligament space and lamina dura), trabecular pattern, and soft tissue. Images were viewed and scored by five calibrated observers, and image quality was ranked from best to worst. The Veraviewepocs 3D had the highest quality images for most of the assessed features, whereas the Iluma low-resolution scans were rated as the lowest quality images.