Neuraminidase produces a decrease of adherence of slime-forming <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> to gelatin-impregnated polyester fiber graft fabric: an experimental study

Because slime-forming microorganisms are the major causative agents of graft infections, we aimed to investigate bacterial adherence in slime-forming and nonslime-forming Staphylococcus aureus and to determine the role of neuraminidase (NANase) on adherence to gelatin-impregnated polyester fiber graft fabric. An in vitro model was developed to quantitatively measure bacterial adherence to the surface of the graft. The grafts were divided into two groups – those colonized with slime-forming S. aureus and those colonized with nonslime-forming S. aureus. The grafts were put into sterile tubes and human plasma was instilled and incubated at 37°C to perform fibrin deposition on the grafts. After 48 h of incubation, grafts were drained and inoculated with slime-forming or nonslime-forming S. aureus in triptic soy broth in the presence or absence of NANase. Following 36 h of incubation at 36°C, grafts were vortexed and cultured to perform a colony count. Bacterial counts were expressed as total colony-forming units per square centimeter of graft. Slime-forming S. aureus had greater affinity with the graft compared with nonslime-forming S. aureus (P < 0.05). The adherence of slime-forming S. aureus was impaired by NANase treatment (P < 0.001) but NANase treatment of nonslime-forming S. aureus did not change the adherence to the graft (P > 0.05). These results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming S. aureus can be decreased by NANase treatment. This may have implications for the development of neuraminidase-embedded vascular grafts to diminish biomaterial-related infections.     

Interactions between lipoxin A4, the stable analogue 16-phenoxy-lipoxin A4 and leukotriene B4 in cytokine generation by human monocytes

Lipoxins display both stimulatory and inhibitory actions with leucocytes that are cell-type dependent. We tested whether lipoxin A4 (LXA4) and its stable synthetic analogue 16-phenoxy-17-18,19,20-tetranor-lipoxin-A4 (16-phe-LXA4) modulated the ability of human blood monocytes (MO) to express mRNA and proteins for interleukin-1beta (IL-1beta), IL-6 and IL-1 receptor antagonist (IL-1Ra) in vitro and compared their actions with lipopolysaccharide (LPS) and leukotriene B4 (LTB4). 16-phe-LXA4, LPS and LTB4, but not LXA4, induced gene expression of IL-1beta in MO. IL-1beta protein synthesis increased by LPS (1500-fold), LTB4 (280-fold) and 16-phe-LXA4 (30-fold). Although the IL-1Ra gene was constitutively activated, mRNA concentration not affected by any of the stimulants, IL-Ra protein synthesis was increased by LPS (with 74%), 16-phe-LXA4 (35%) and LTB4 (20%), but not by LXA4. Each of these stimuli upregulated the IL-6 gene. Increases of IL-6 protein were 3000-fold for LPS, threefold for 16-phe-LXA4, eightfold for LXA(4 and) twofold for LTB4. Prior exposure of MO to 16-phe-LXA4, but not LXA4, reduced LTB4 induced synthesis of IL-1beta with 66%, IL-6 with 20% and IL-1Ra with 29%. Thus, a stable LXA analogue, that resists rapid inactivation by monocytes, displays novel actions in cytokine generation, intimately involved in the regulation of inflammation.     

The prevalence of metabolic syndrome is increased in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

Purpose

Cardiovascular disease is one of the major causes of mortality in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Metabolic syndrome (MetS) is associated with increased cardiovascular risk in the normal population. However, MetS in AAV has not been adequately investigated. We aimed to determine MetS prevalence and associated factors in AAV patients.

Methods

Thirty-seven AAV patients and 42 healthy controls were enrolled. MetS was determined by International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) criteria. The relationship between clinical features of AAV and MetS was also investigated.

Results

MetS was significantly higher in AAV patients than controls by NCEP-ATPIII (51.4% vs. 26.2%, p 0.022) and IDF (62.2% vs. 35.7%, p 0.020). When AAV patients with MetS were compared to those without, there were significant differences in age, CRP, GFR and NT-pro-BNP. Age [58 (13) vs. 50 (8) years p: 0.028], CRP [4.0 (3.6) vs. 3.2 (1.0) mg/l, p 0.021] and NT-pro-BNP [173.5 (343.7) vs. 106.0 (103.0) pg/ml, p 0.013] were significantly higher in AAV patients with MetS than those without; GFR was significantly lower [38 (46) vs. 83 (51) ml/min/1.73 m², p 0.004]. ROC curve analysis showed NT-pro-BNP?>?58.0 ng/ml predicted MetS with 87.1% sensitivity and 46.7% specificity (Area under curve: 0.71, CI 0.536–0.902, p 0.041). Multivariate analysis revealed age [OR (95% CI): 1.180 (1.010–1.370), p 0.039] and NT-pro-BNP?>?58 pg/ml [OR (95% CI): 5.5 (1.02–30.1) p 0.047] were independent predictors of MetS in AAV patients.

Conclusion

MetS is significantly higher in AAV patients than controls and is associated with age and NT-pro-BNP. Screening and treating MetS may improve prognosis in AAV patients.

     

On the stereochemistry and biosynthesis of lipoxin B.

Lipoxin B (LXB) was prepared by incubation of (15S)-15-hydroperoxy-5,8,11-cis-13-trans-icosatetraenoic acid (15-HPETE) with human leukocytes. Comparison with a number of trihydroxyicosatetraenes prepared by total synthesis showed that biologically derived LXB is (5S,14R,15S)-5,14,15-trihydroxy-6,10,12-trans-8-cis-icosatetraenoi c acid. Two isomers of LXB were identified by using an improved isolation procedure. These compounds were shown to be (5S,14R,15S)-5,14,15-trihydroxy-6,8,10,12-trans-icosatetraenoic acid (8-trans-LXB) and (5S,14S,15S)-5,14,15-trihydroxy-6,8,10,12-trans-icosatetraenoic acid [(14S)-8-trans-LXB]. Experiments with 18O2 showed that formation of LXB and its two isomers occurred with incorporation of molecular oxygen at C-5 but not at C-14. These results together with the finding that (15S)-hydroxy-5,8,11-cis-13-trans-icosatetraenoic acid (15-HETE) is a precursor of LXB compounds in activated leukocytes suggest that 15-hydroxy-5,6-epoxy-7,9,13-trans-11-cis-icosatetraenoic acid or its equivalent is a common intermediate in the biosynthesis of LXB and its two isomers.     

The potential effect of anatomic relationship between the femur and the tibia on medial meniscus tears

Background

The anatomic and the kinematical relationships between the femur and the tibia have been previously examined in both normal and diseased knees. However, less attention has been directed to the effect of these relationships on the meniscal diseases. Therefore, we aimed to investigate the impact of femorotibial incongruence on both lateral and medial meniscal tears.

Materials and methods

A total of 100 images obtained from MRI of 100 patients (39 males and 61 females) were included in the study. Diameters of the medial and the lateral femoral condyles, thicknesses of the menisci, and diameters of the medial and the lateral tibial articular surfaces were measured.

Results

The medial meniscus tear was detected in 40 (40 %) patients. However, no lateral meniscus tear was found. Significant relationships were found between the diameters of the posterior medial femoral condyle and the medial tibial superior articular surface and between the diameters of the posterior lateral femoral condyle and the lateral tibial superior articular surface. The mean values for the diameter of the medial condyle of the femur, the lateral condyle of the femur, the medial superior articular surface of the tibia, and the lateral superior articular surface of the tibia were found to be significantly higher in cases with meniscus tear compared to cases without meniscus tear. However, no significant difference was present regarding the thicknesses of the medial and the lateral menisci. A positive relationship between the diameter of the posterior medial femoral condyle and the tibial medial superior articular surface was found in cases with (n = 40) (r ² = 0.208, p = 0.003) and without tear (n = 60) (r ² = 0.182, p = 0.001). In addition, a significant positive relationship was found between the diameter of the posterior medial femoral condyle and the medial tibial superior articular surface in cases with and without tear.

Conclusion

The impact of femorotibial incongruence on the medial meniscus tear is important for the understanding of the lesions.     

Waist circumference is associated with carotid intima media thickness in peritoneal dialysis patients

Purpose

Atherosclerosis is responsible for the high mortality rate in end-stage renal disease patients. Defining risk factors for atherosclerosis may lead to reduction in cardiovascular disease through modification of these factors. Peritoneal dialysis (PD) patients are subjected to high glucose loads on a daily basis, which results in considerable weight gain and an increase in waist circumference (WC). WC as an indicator of abdominal obesity is a risk factor for atherosclerosis in the general population. Carotid artery intima media thickness (CIMT) measurement is a reliable method for the detection of early atherosclerosis. The aim of this study was to investigate the relationship between WC and CIMT and to define risk factors associated with CIMT in PD patients.

Methods

Fifty-five PD patients and 40 healthy controls were included. Atherosclerosis was assessed using measurement of CIMT. Fasting blood was collected for analysis. Anthropometric parameters (age, weight, BMI, and WC) were measured.

Results

Peritoneal dialysis patients had higher WC (93.9 ± 1.7 vs. 87.3 ± 1.2 cm, p < 0.05) and CIMT (0.70 ± 0.02 vs. 0.57 ± 0.01 mm, p < 0.01) than the control group. On univariate analysis, age, WC, plaque formation, and D/P creatinine were positively correlated with CIMT, whereas residual renal function, albumin, ultrafiltration volume, and D/D0 glucose were negatively correlated. On multivariate analysis, only age, WC, and plaque formation showed correlation (p < 0.001).

Conclusions

Carotid artery intima media thickness is associated with age, plaque formation, and WC in PD patients. WC measurement is a simple, inexpensive, reproducible, and reliable method of evaluating atherosclerosis risk in PD patients and should be assessed at every visit. Appropriate counsel should be provided to patients with greater WC who are deemed to be at risk for atherosclerosis.     

A rare cause of deep peroneal nerve palsy due to compression of synovial cyst – Case report

INTRODUCTIONSynovial cyst is a rare cause of compression neuropathy and its differential diagnosis can be misleading.PRESENTATION OF CASEThis article presents clinical, radiological, and histological findings of deep peroneal nerve palsy due to compression of a synovial cyst in a 30-year-old patient admitted with sudden drop foot.DISCUSSIONFocal nerve entrapment in lower extremity due to synovial cystis a rare entity. Differential diagnosis is important. Surgical excision is the main treatment method with high success rate.CONCLUSIONSynovial cyst compression which can be treated easily with surgical excision should be considered in rapidly progressed drop foot.