Direct binding of respiratory syncytial virus to pneumococci: a phenomenon that enhances both pneumococcal adherence to human epithelial cells and pneumococcal invasiveness in a murine model

In a previous study we showed that pneumococcal adherence to epithelial cells was enhanced by a preceding respiratory syncytial virus (RSV) infection. RSV-glycoproteins, expressed on the infected cell surface, may play a role in this enhanced pneumococcal binding, by acting as bacterial receptors. In the current study, it was attempted to analyze the capacity of pneumococci to interact directly with RSV virions. By flow-cytometry, a direct interaction between RSV and pneumococci could be detected. Heparin, an inhibitor of RSV infectivity that interacts with RSV protein-G, blocked RSV-pneumococcal binding, indicating that the latter interaction is indeed mediated by protein-G. RSV-pneumococcal complexes showed enhanced adherence to uninfected human epithelial cells, compared with pneumococcal adherence without bound RSV, and this enhancement was also blocked by heparin. In addition, the significance of these findings in vitro was explored in vivo in a murine model. Both mice that were pretreated with RSV at day 4 before pneumococcal challenge and mice infected with both agents simultaneously showed significantly higher levels of bacteraemia than controls. Simultaneous infection with both agents enhanced the development of pneumococcal bacteraemia most strongly. It was hypothesized that direct viral binding is another mechanism by which RSV can induce enhanced pneumococcal binding to epithelial cells, a phenomenon that is translated in vivo by a higher invasiveness of pneumococci when administered simultaneously with RSV to mice. Apparently, RSV acts in this process as a direct coupling particle between bacteria and uninfected epithelial cells, thereby increasing colonization by and enhancing invasiveness of pneumococci.     

Convection perfusion of glucocerebrosidase for neuronopathic Gaucher's disease

Systemic enzyme replacement for Gaucher's disease has not prevented premature death or severe morbidity in patients with a neuronopathic phenotype, because the enzyme does not cross the blood-brain barrier. We used convection-enhanced delivery for regional distribution of glucocerebrosidase in rat and primate brains and examined its safety and feasibility for neuronopathic Gaucher's disease. Rats underwent intrastriatal infusion and were observed and then sacrificed at 14 hours, 4 days, or 6 weeks. Primates underwent serial magnetic resonance imaging during enzyme perfusion of the right frontal lobe or brainstem, were observed and then sacrificed after infusion completion. Animals underwent histologic and enzymatic tissue analyses. Magnetic resonance imaging revealed perfusion of the primate right frontal lobe or pons with infusate. Enzyme activity was substantially and significantly (p < 0.05) increased in cortex and white matter of the infused frontal lobe and pons compared to control. Immunohistochemistry demonstrated intraneuronal glucocerebrosidase. There was no toxicity. Convection-enhanced delivery can be used to safely perfuse large regions of the brain and brainstem with therapeutic levels of glucocerebrosidase. Patients with neuronopathic Gaucher's disease and similar central nervous system disorders may benefit from this treatment.     

Gastro-intestinal stromal tumour of the duodenum: extreme presentation in two cases

Gastro-intestinal stromal tumours (GIST) are primary mesenchymal tumours arising from the gastro-intestinal tract. They are uncommon visceral tumours, preferentially located in the stomach and small intestine. The present paper will discuss the clinical presentation of GIST in a 32-year-old female (Case 1) and in a 72-year-old female (Case 2). In both cases the tumour is located in the duodenum which appears to be a rather unusual location (4%) for GIST. This work will illustrate that duodenal GIST can occur in extreme presentations, diverging from vague complaints to directly life threatening symptoms.     

alpha-Galactosidase A deficiency in Dutch patients on dialysis: a critical appraisal of screening for Fabry disease.

INTRODUCTION: Fabry disease or alpha-galactosidase A (alpha-Gal A) deficiency is an X-linked lysosomal storage disorder that often leads to renal insufficiency in males and occasionally in females. The disease is rare, but its prevalence may be underestimated due to its variable clinical picture. Enzyme supplementation therapy with rHu-alphaGal A is currently available. Limited experience has so far shown that therapy may at best stabilize renal function. Despite these preliminary findings, much effort is being put into screening high-risk groups for undiagnosed alpha-Gal A deficiency. We studied the prevalence of alpha-Gal A deficiency in a Dutch dialysis cohort to establish possible underdiagnosis. We discuss the benefits of screening for Fabry disease. METHODS: Activity of alpha-Gal A in whole blood was measured in a group of 508 male Dutch dialysis patients. RESULTS: Of the 508 patients studied only one patient, already known with Fabry disease, had a alpha-Gal A deficiency, a prevalence of 0.22% (95 CI 0-1.1%). CONCLUSIONS: No undiagnosed Fabry patients were found, indicating that in our studied cohort there is no large-scale underestimation of its prevalence. Even though screening of dialysis patients for Fabry disease might identify patients who remain otherwise unrecognized, screening of high-risk populations for alpha-Gal A deficiency should be carried out with caution since long-term efficacy of treatment is currently unknown.     

Emergency room retrograde transbrachial arteriography for the management of axillosubclavian vascular injuries

BACKGROUND: Our purpose was to determine the accuracy of single-injection, retrograde transbrachial arteriography (RTBA), performed in the emergency room, for suspected axillosubclavian injuries. METHODS: Thirty-three patients were prospectively assigned for RTBA. Clinical indications for RTBA included high-risk mechanism of injury, decreased (n = 19) or absent (n = 5) brachial pulse, neurologic deficits (n = 11), external or intrathoracic bleeding (n = 4), and bruit (n = 2). Brachial artery was cannulated with an 18-gauge catheter. A sphygmomanometer cuff was placed at the forearm and inflated to 250 mm Hg. Twenty milliliters of nonionic contrast media was injected countercurrent and a single anteroposterior chest radiograph was obtained. Small intimal flaps were followed by serial ultrasound. Surgical findings were used to establish RTBA accuracy. RESULTS: RTBA was successfully performed in all cases. Arterial lesions were detected in 28 (84.8%) patients, including thrombosis (n = 8), arteriovenous fistula (n = 8), and false aneurysm (n = 7) as the most frequent lesions. A sensitivity of 96.5%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 80% were observed with RTBA. CONCLUSION: We conclude that RTBA is a safe and accurate technique to be used in the emergency room for the rapid detection of axillosubclavian arterial injuries.     

Validation and reproducibility of computerised cell-viability analysis of tissue slices

Background

The identification of live cells using membrane integrity dyes has become a frequently used technique, especially with articular cartilage and chondrocytes in situ where tissue slices are used to assess cell recovery as a function of location. The development of a reproducible computerised method of cell evaluation would eliminate many variables associated with manual counting and significantly reduce the amount of time required to evaluate experimental results.

Methods

To validate a custom computerised counting program, intra-person and inter-person cell counts of nine human evaluators (three groups – unskilled, novice, and experienced) were compared with repeated pixel counts of the custom program on 15 digitised images (in triplicate) of chondrocytes in situ stained with fluorescent dyes.

Results

Results indicated increased reproducibility with increased experience within evaluators [Intraclass Correlation Coefficient (ICC) range = 0.67 (unskilled) to 0.99 (experienced)] and between evaluators [ICC = 0.47 (unskilled), 0.85 (novice), 0.93 (experienced)]. The computer program had perfect reproducibility (ICC = 1.0). There was a significant relationship between the average of the experienced evaluators results and the custom program results (ICC = 0.77).

Conclusions

This study demonstrated that increased experience in cell counting resulted in increased reproducibility both within and between human evaluators but confirmed that the computer program was the most reproducible. There was a good correlation between the intact cell recovery determined by the computer program and the experienced human evaluators. The results of this study showed that the computer counting program was a reproducible tool to evaluate intact cell recovery after use of membrane integrity dyes on chondrocytes in situ. This and the significant decrease in the time used to count the cells by the computer program advocate its use in future studies because it has significant advantages.

     

Prevalence and risk factors for anemia among children in Brazil

OBJECTIVE: To verify the prevalence of anemia among children aged 0 to 36 months, who attend public day care centers in Porto Alegre, Brazil, and assess its possible risk factors. METHODS: A cross-sectional study was carried out in 557 children aged 0 to 36 months of all public day care centers in Porto Alegre. Anthropometric measurements and hemoglobin levels were performed. The portable HemoCue photometer was employed to measure hemoglobin levels, and anemia was considered when the hemoglobin level was below 11 g/dl. Information regarding each child was obtained by means of a questionnaire applied to the mother. The association of the variables studied to anemia was analyzed using the log-binomial regression technique applied to the hierarchical model. RESULTS: A 47.8% prevalence of anemia was found in this population. The risk factors for anemia in the studied group were: families with per capita income equal or less than one monthly minimal wage (prevalence ratio - RP =1.6), age between 12 and 23 months (RP=1.4), and having 2 or more siblings younger than 5 years old (RP=1.4). CONCLUSIONS: There is a high prevalence of anemia among children aged 0 to 36 months in public day care centers, especially among children with the lowest socioeconomic level, in the 12 to 23 months age group, and who have 2 or more siblings under 5 years of age, indicating that there is an urgent need for effective measures to fight and prevent this condition.