Group A Streptococci from carriage and disease in Portugal: evolution of antimicrobial resistance and T antigenic types during 2000-2002

In this study, we analyzed the antimicrobial resistance properties and T antigenic types of 511 isolates collected in Lisbon district, Portugal, from throat swabs of healthy subjects (n=341), during 2000-2002 and from diverse infection sites (n=170) of outpatients and inpatients, during 1999-2002. Erythromycin resistance was higher in tonsillitis/pharyngitis (27.4%) and skin infection isolates (21.1%), than in carriage and invasive isolates (相似文献   

Control of grasp stability in humans under different frictional conditions during multidigit manipulation

Control of grasp stability under different frictional conditions has primarily been studied in manipulatory tasks involving two digits only. Recently we found that many of the principles for control of forces originally demonstrated for two-digit grasping also apply to various three-digit grasps. Here we examine the control of grasp stability in a multidigit task in which subjects used the tips of the thumb, index, and middle finger to lift an object. The grasp resembled those used when lifting a cylindrical object from above. The digits either all contacted the same surface material or one of the digits contacted a surface material that was more, or less, slippery than that contacted by the other two digits. The three-dimensional forces and torques applied by each digit and the contact positions were measured along with the position and orientation of the object. The distribution of forces among the digits strongly reflected constraints imposed by the geometric relationship between the object's center of mass and the contact surfaces. On top of this distribution, we observed changes in force coordination related to changes in the combination of surface materials. When all digits contacted the same surface material, the ratio between the normal force and tangential load (F(n):L ratio) was similar across digits and scaled to provide an adequate safety margin against slip. With different contact surfaces subjects adapted the F(n):L ratios at the individual digits to the local friction with only small influences by the friction at the other two digits. They accomplished this by scaling the normal forces similarly at all digits and changing the distribution of load among the digits. The surface combination did not, however, influence digit position, tangential torque, or object tilting systematically. The change in load distribution, rather, resulted from interplay between these factors, and the nature of this interplay varied between trials. That is, subjects achieved grasp stability with various combinations of fingertip actions and appeared to exploit the many degrees of freedom offered by the multidigit grasp. The results extend previous findings based on two-digit tasks to multidigit tasks by showing that subjects adjust fingertip forces at each digit to the local friction. Moreover, our findings suggest that subjects adapted the load distribution to the current frictional condition by regulating the normal forces to allow slips to occur early in the lift task, prior to object lift-off.     

Sex Differences in the Catecholamine Output of Children

Urinary excretion of catecholamines was studied in 240 normal, healthy children 12 years of age during a passive condition (film exposure) and an active condition (arithmetic test) at school. No sex differences in catecholamine excretion were found during the passive condition, whereas, during the work period, boys excreted significantly more adrenaline and noradrealine than girls. A comparison is made between catecholamine excretion levels of the children and adult subjects examined in other studies.     

Omalizumab and the immune system: an overview of preclinical and clinical data.

OBJECTIVE: This review discusses the role of immunoglobulin (Ig)E in allergic disease, inhibition of IgE with omalizumab, and the consequences of IgE inhibition (both clinically and in terms of the effect on the immune system). DATA SOURCES: Relevant publications obtained from a literature review. STUDY SELECTION: Relevant publications on IgE, allergic disease, and anti-IgE were critically evaluated. RESULTS: IgE plays a key role in allergic diseases such as allergic asthma and allergic rhinitis. Its role in healthy individuals is less well defined. Treatment of allergic asthma and rhinitis with omalizumab, a humanized monoclonal anti-IgE antibody, causes a marked reduction in circulating free IgE levels. This has been shown to reduce symptoms and decrease the need for other medication in patients with these allergic diseases. Anti-IgE treatment with omalizumab did not cause any of the complications that might, in theory, be expected to result from reduction in circulating free IgE, such as adverse effects upon the immune system or other body systems. CONCLUSIONS: The limited clinical data currently available suggest that this novel method of treatment for allergic asthma and rhinitis seems to be both effective and well tolerated in clinical use.     

Predominant pathogenic role of tumor necrosis factor in experimental colitis in mice

Antibodies to tumor necrosis factor (TNF)-α have been recently proposed as effective treatment for patients with Crohn's disease. Here, we analyze the functional role of TNF-α in a mouse model of chronic intestinal inflammation induced by the hapten reagent 2,4,6,-trinitrobenzene sulfonic acid (TNBS) that mimics some characteristics of Crohn's disease in humans. Macrophage-enriched lamina propria (LP) mononuclear cells from mice with TNBS-induced colitis produced 10–30-fold higher levels of TNF-α mRNA and protein than cells from control mice. When mice with chronic colitis were treated by intraperitoneal injection of antibodies to TNF-α, an improvement of both the clinical and histopathologic signs of disease was found. Isolated macrophage-enriched LP cells from anti-TNF-α-treated mice produced strikingly less pro-inflammatory cytokines such as interleukin (IL)-1 and IL-6 in cell culture. The predominant role of TNF-α in the mouse TNBS-induced colitis model was further underlined by the finding that striking colonic inflammation and lethal pancolitis was induced in TNF-α-transgenic mice upon TNBS treatment. Conversely, no significant TNBS-induced colitis could be induced in mice in which the TNF-α gene had been inactivated by homologous recombination. Complementation of TNF-α function in TNF^?/? mice by the expression of a mouse TNF-α transgene was sufficient to reverse this effect. Taken together, the data provide direct evidence for a predominant role of TNF-α in a mouse model of chronic intestinal inflammation and encourage further clinical trials with antibodies to TNF-α for the treatment of patients with Crohn's disease.     

Evidence for the involvement of the posterior parietal cortex in coordination of fingertip forces for grasp stability in manipulation

Grasp stability during object manipulation is achieved by the grip forces applied normal to the grasped surfaces increasing and decreasing in phase with increases and decreases of destabilizing load forces applied tangential to the grasped surfaces. This force coordination requires that the CNS anticipates the grip forces that match the requirements imposed by the self-generated load forces. Here, we use functional MRI (fMRI) to study neural correlates of the grip-load force coordination in a grip-load force task in which six healthy humans attempted to lift an immovable test object held between the tips of the right index finger and thumb. The recorded brain activity was compared with the brain activity obtained in two control tasks in which the same pair of digits generated forces with similar time courses and magnitudes; i.e., a grip force task where the subjects only pinched the object and did not apply load forces, and a load force task, in which the subjects applied vertical forces to the object without generating grip forces. Thus neither the load force task nor the grip force task involved coordinated grip-load forces, but together they involved the same grip force and load force output. We found that the grip-load force task was specifically associated with activation of a section of the right intraparietal cortex, which is the first evidence for involvement of the posterior parietal cortex in the sensorimotor control of coordinated grip and load forces in manipulation. We suggest that this area might represents a node in the network of cortical and subcortical regions that implement anticipatory control of fingertip forces for grasp stability.     

Neuropeptide changes in a primate model (Cebus apella) for tardive dyskinesia.

Tardive dyskinesia has been connected with regional reductions of GABA functions in the basal ganglia. In view of the possibility that peptides are involved in neuroleptic-induced dyskinesias substance P and dynorphin A levels were measured in the basal ganglia of the Cebus apella model for tardive dyskinesia. In addition, regional glutamate decarboxylase activities, dopamine, homovanillic acid and dihydroxyphenylacetic acid levels were monitored. A significant dyskinesia-related decrease in glutamate decarboxylase activity was found in the subthalamic nucleus, the medial segment of globus pallidus and the rostral part of substantia nigra in accordance with earlier findings. Cebus monkeys with an intact GABA system (neuroleptic-treated controls without dyskinesia) showed increased levels of substance P and homovanillic acid in the caudate nucleus. The changes were confined to the caudal part of the body of the caudate and the nucleus accumbens. On the other hand, the dyskinetic monkeys, with a defective GABA system, did not demonstrate a similar substance P rise in the caudate or nucleus accumbens, but showed a depression of homovanillic acid levels in the caudal part of the body of the caudate nucleus. Dynorphin A, dopamine and dihydroxyphenylacetic acid showed no dyskinesia-related changes. In conclusion, the difference in glutamate decarboxylase activity between animals developing dyskinetic symptoms vs those who did not, was reflected by regional changes in substance P and homovanillic acid levels.     

Trisomy 7 in nonneoplastic focal steatosis of the liver.

Cytogenetic analysis of short-term cultures of a nonneoplastic focal steatosis of the liver showed trisomy 7 as the sole chromosomal change. This finding, especially when viewed in light of previous reports describing +7 in nonneoplastic tissues, strongly suggests that trisomy 7 cannot be considered a tumor-specific abnormality when it occurs as the only change. The cell type in which +7 is present is not yet known.     

Immunohistochemical examination of 25 cases of Merkel cell carcinoma: a comparison with small cell carcinoma of the lung and oesophagus, and a review of the literature.

Merkel cell carcinomas (MCC) were compared to small cell carcinomas of the lung (SCCL) and oesophagus (SCCO). Most MCC were of the intermediate cell type while SCCL and SCCO were usually of the small cell type. Only MCC of trabecular type could be separated from SCCL and SCCO by means of histopathological examination alone. All MCC (25) stained with cytokeratin CAM 5.2, 20 of which in a "paranuclear globular" or combined "paranuclear globular"/diffuse pattern while 17 MCC stained with cytokeratin AE1/AE3. Cytokeratin CAM 5.2 reacted with 60 percent of the SCCL and 86 percent of the SCCO, and cytokeratin AE1/AE3 with 33 and 28 percent respectively. Neurofilament stained 17 MCC in a "paranuclear globular" pattern but none of the SCCL and SCCO. All MCC with a diffuse staining pattern for cytokeratin CAM 5.2 were negative for neurofilament. The results of this study and review of the literature indicate that in most instances Merkel cell carcinoma can be separated from other SCC, pulmonary as well as extrapulmonary, by means of histopathological and, above all, immunohistochemical examinations.     

Cell cycle arrest of human gingival fibroblasts and periodontal ligament cells by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin

The cytolethal distending toxin (Cdt) is produced by several Gram-negative bacterial species and causes growth arrest and morphological alterations in mammalian cells. Actinobacillus actinomycetemcomitans, which is involved in the pathogenesis of localized aggressive periodontitis, also produces a Cdt that affects periodontal connective tissue cells. The aim of this study was to investigate in which phase of the cell cycle these cells are arrested and enlarged when challenged with A. actinomycetemcomitans, and to evaluate the involvement of its Cdt. Human gingival fibroblasts and periodontal ligament cells were challenged with A. actinomycetemcomitans extract, or with purified Cdt, and cell cycle analysis was performed by propidium iodide staining and flow cytometry. Cells exposed to an A. actinomycetemcomitans wild-type strain, or to purified Cdt, were arrested in both G1 and G2/M phases, and appeared enlarged compared to the corresponding controls. The cellular enlargement occurred in both G1 and G2/M arrested cells. In contrast, cells exposed to an A. actinomycetemcomitans cdt-knockout mutant strain showed cell cycle phase distribution and size similar to the controls. In conclusion, A. actinomycetemcomitans causes a combined G1 and G2/M growth arrest and enlargement in periodontal connective tissue cells, which is attributed to its Cdt.