Immunodeficiency and autoimmunity coming together: a nearly missed diagnosis.

The coexistence of human immunodeficiency virus (HIV) and systemic lupus erythematosus (SLE) appears to be unusual and the prevalence of patients who carry the dual diagnosis is currently unknown. We hereby present a case of a C4 deficient HIV-1 positive Caucasian female under highly active antiretroviral therapy for the past eight years, admitted to hospital with an aggressive and potentially fatal clinical presentation of SLE. There was a favorable outcome despite a significant diagnostic delay. Despite its rarity, the case highlights that this association is remarkable and may be overlooked by clinicians familiar with either condition.

Virulence factors and infection ability of Pseudomonas aeruginosa isolates from a hydropathic facility and respiratory infections.

AIMS: To compare the virulence pool and acute infection ability of Pseudomonas aeruginosa isolates from a hydropathic facility, used to treat respiratory conditions by inhalation of untreated natural mineral water, with clinical isolates from respiratory infections. METHODS AND RESULTS: Pseudomonas aeruginosa isolates from a hydropathic facility and from respiratory infections were typed by pulsed-field gel electrophoresis. Nonclonal representatives of each population were selected. 18 virulence-encoding genes were screened by polymerase chain reaction and statistically compared by multiple correspondence analysis. Homogeneous distribution of genes between populations but higher genetic association in aquatic isolates was observed, as well as distinct virulence pool according to location in the water system. Acute infection ability of selected isolates from each population, in Galleria mellonella model, showed lower LD50 of the majority of the hydropathic isolates and significant variations in LD50 of biofilm isolates from different equipments. CONCLUSIONS: Hydrotherapy Ps. aeruginosa isolates present similar virulence to isolates from respiratory infections. Hydrotherapy users may be exposed to different microbiological risks when using different treatment equipments. SIGNIFICANCE AND IMPACT OF THE STUDY: Twenty-one million people use hydropathic facilities in Europe, and the majority present risk factors to pneumonia. This study demonstrates the health risk associated with this practice. Revision of European regulations should be considered.

Pseudomonas aeruginosa in a hydropathic facility: diversity, susceptibility and imipenem resistance mutation.

AIMS: To detect Pseudomonas aeruginosa in water and treatment equipment biofilms of a thermae hydropathic facility and to study antibiotic susceptibility and genetic diversity. METHODS AND RESULTS: One hundred and fifty-four planktonic isolates were obtained from 2220 water samples during 4 years. Seventy-two biofilm isolates were obtained from 23 samples of inner parts of three inhalation equipments. Antibiotic susceptibility was determined by disc diffusion. All isolates were susceptible to tested antimicrobials, except two biofilm isolates and one planktonic isolate. Twenty-one resistant mutants were observed (nine from biofilms), mostly with imipenem (IP) resistance (81%), by diminished expression of OprD porin, as it was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Random amplification polymorphic DNA showed a genetically heterogeneous population that is spread through the entire system and persistent in time. IP resistance mutation ability was spread through the population. CONCLUSIONS: The permanent assessment of Ps. aeruginosa is necessary not only in water, as expressed in official programmes, but also in equipments where biofilms are evident. Ps. aeruginosa was more prevalent in biofilm populations and presented higher ability to adapt to antibiotic pressure. SIGNIFICANCE AND IMPACT OF THE STUDY: Twenty-one million people use thermae in Europe. Official microbiological quality control programmes only consider water surveillance. Present study proves the need of a review on current official programmes.

Elastic turbulence in shear banding wormlike micelles.

We study the dynamics of the Taylor-Couette flow of shear banding wormlike micelles. We focus on the high shear rate branch of the flow curve and show that for sufficiently high Weissenberg numbers, this branch becomes unstable. This instability is strongly subcritical and is associated with a shear stress jump. We find that this increase of the flow resistance is related to the nucleation of turbulence. The flow pattern shows similarities with the elastic turbulence, so far only observed for polymer solutions. The unstable character of this branch led us to propose a scenario that could account for the recent observations of Taylor-like vortices during the shear banding flow of wormlike micelles.

Microplates: a new tool for manipulation and mechanical perturbation of individual cells.

We present a new type of microinstrument allowing manipulation and mechanical perturbation of individual cells under an optical microscope. These instruments, which we call microplates, are pulled from rectangular glass bars. They have flat tips, typically 2 microm thick x 20 microm wide, whose specific shape and stiffness can be adjusted through the pulling protocol. After appropriate chemical treatment, microplates can support cell adhesion and/or spreading. Rigid microplates are used to hold cells, whereas more flexible ones serve as stress sensors, i.e. their deflexion is used to probe forces in the range of 1-1000 nN. The main advantages of microplates are their simple geometry and surface properties, and their ability to provide mechanical measurements. In this methodological paper, we give details about microplate preparation and adhesiveness, manipulation set-up, force calibration, and image analysis. Several manipulations have already been carried out on fibroblasts, including uniaxial deformation, micropipet aspiration of adherent cells, and cell-substrate separation. Our results to date provide new insights into the morphology, mechanical properties, and adhesive resistance of cells. Many future applications can be envisaged.

Model of computerized academic medical clinic.

In the traditional medical graduation course, the student receives a great amount of information while training at the Outpatient Care; the student assumes the physician's role, collecting all the information regarding the patient's clinical history and learns to get along with patients as well. During the attendance process, several factors interfere in the academic teaching, such as limitations of room numbers, amount of patients, difficulties in obtaining medical records, paper illegibility, among other problems. Due to those difficulties, the Model of Computerized Academic Health Clinic, implies in a new learning paradigm in the medical practice, rethinking the traditional process of learning-attendance, where the old model, in which attendance is restricted to a place, is extended in an open atmosphere of shared knowledge, rich of computer resources. The pilot project was implanted in the Pediatrics General Health Clinic of UNIFESP/EPM. It allows that the fifth-year medical students, residents, trainees and tutors use computerized clinics, connected with the academic net of UNIFESP and to the Internet. All the computing and information resources settled at the Outpatient Care improved the organization of its services, increased the medical students' curiosity, improved their participation in learning through interactive programs and clinical attendance.

[The hemolytic-uremic syndrome]. / Síndrome hemolítico-urémico.

The microangiopathic thrombotic syndromes--thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS)--are characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal dysfunction, fever and central nervous system abnormalities. Today they are considered as two extremes of a continuous spectrum named TTP--HUS. The syndrome is an uncommon disease with a high mortality rate, despite treatment. The authors describe a case of hemolytic uremic syndrome in a young adult patient. Initially the clinical course and the first biopsy suggested a favourable prognosis, but the early recurrence with severe hypertension was followed by a fatal outcome 6 months later. Concerning this clinical case, the authors present a review of the most recent aspects of the pathogenesis and treatment of this syndrome.

Mobile genetic elements of Pseudomonas aeruginosa isolates from hydrotherapy facility and respiratory infections.

The content of mobile genetic elements in Pseudomonas aeruginosa isolates of a pristine natural mineral water system associated with healthcare was compared with clinical isolates from respiratory infections. One isolate, from the therapy pool circuit, presented a class 1 integron, with 100% similarity to a class 1 integron contained in plasmid p4800 of the Klebsiella pneumoniae Kp4800 strain, which is the first time it has been reported in P. aeruginosa. Class 1 integrons were found in 25.6% of the clinical isolates. PAGI1 orf3 was more prevalent in environmental isolates, while PAGI2 c105 and PAGI3 sg100 were more prevalent in clinical isolates. Plasmids were not observed in either population.

Helicobacter pylori antimicrobial resistance rates in the central region of Portugal.

Helicobacter pylori resistance to antimicrobial agents is steadily increasing. It is extremely important to be aware of the local prevalence of antibiotic resistance so as to adjust treatment strategies. During this single-centre, prospective study, we aimed to determine primary and secondary resistance rates of H. pylori to antibiotics as well as host and bacterial factors associated with this problem. Overall, 180 patients (131 female; mean age 43.4±13.5 years; primary resistance 103; secondary resistance 77) with positive (13) C-urea breath test were submitted to upper endoscopy with gastric biopsies. Helicobacter pylori was cultured and antimicrobial susceptibility was determined by Etest and molecular methods. Clinical and microbiological characteristics associated with resistance were evaluated by logistic regression analysis. Among the 180 isolates 50% were resistant to clarithromycin (primary 21.4%; secondary 88.3%), 34.4% to metronidazole (primary 29.1%; secondary 41.6%), 33.9% to levofloxacin (primary 26.2%; secondary 44.2%), 0.6% to tetracycline and 0.6% to amoxicillin. Being female was an independent predictor of resistance to clarithromycin and metronidazole. Previous, failed, eradication treatments were also associated with a decrease in susceptibility to clarithromycin. History of frequent infections, first-degree relatives with gastric carcinoma and low education levels determined increased resistance to levofloxacin. Mutations in the 23S rRNA and gyrA genes were frequently found in isolates with resistance to clarithromycin and levofloxacin, respectively. This study revealed that resistance rates to clarithromycin, metronidazole and levofloxacin are very high and may compromise H. pylori eradication with first-line and second-line empiric triple treatments in Portugal.

Analyzing the interplay between single cell rheology and force generation through large deformation finite element models.

In this study, experimental results of single cell spreading between two parallel microplates are exploited through finite element modeling. Axisymmetric computations at finite strains are performed to extract the mechanical properties of the cell which can account for cell shape evolution and traction force generation. Our model includes two distinct components representing the cortex associated with the bilayer membrane on the one hand, and the rest of the cell on the other hand. The former is modeled as a homogeneous hyperelastic material described by a slightly compressible Gent strain energy function, while the latter is idealized either as a quasi-incompressible Newtonian fluid or as another homogeneous hyperelastic material. The kinetics of spreading is ensured by a stapling procedure defined from experimental observations. Material parameters are then optimized to match the simulation closely with the experimental data. In particular, the elastic modulus of the cortex is estimated at about 1,000 Pa in both models, while the cell interior is characterized by a viscosity of 1,000 Pa.s in the biphasic model, or by an elastic modulus of about 100 Pa in the hyperelastic one. These results are in good agreement with G(') and G('') measurements carried out previously in the same parallel plates setup and estimated at the typical rate of cell straining. Moreover, stresses are found to concentrate at the edge of the cell-substrate contact area. These observations allow explaining the relationship between cell spreading and force increase since spreading and the consequent straining of the cell mechanical structure could be the source of the force applied by the cell on its substrate. They could also explain, in a very simple manner, why force-sensitive focal contacts concentrate at the cell edges.

Taylor-like vortices in shear-banding flow of giant micelles.

Using flow visualizations in Couette geometry, we demonstrate the existence of Taylor-like vortices in the shear-banding flow of a giant micelles system. We show that vortices stacked along the vorticity direction develop concomitantly with interfacial undulations. These cellular structures are mainly localized in the induced band and their dynamics is fully correlated with that of the interface. As the control parameter increases, we observe a transition from a steady vortex flow to a state where pairs of vortices are continuously created and destroyed. Normal stress effects are discussed as potential mechanisms driving the three-dimensional flow.

Changes in the mechanical properties of fibroblasts during spreading: a micromanipulation study.

Cell morphology is controlled in part by physical forces. If the main mechanical properties of cells have been identified and quantitated, the question remains of how the cell structure specifically contributes to these properties. In this context, we addressed the issue of whether cell rheology was altered during cell spreading, taken as a fundamental morphological change. On the experimental side, we used a novel dual micromanipulation system. Individual chick fibroblasts were allowed to spread for varying amounts of time on glass microplates, then their free extremity was aspirated into a micropipet at given pressure levels. Control experiments were also done on suspended cells. On the theoretical side, the cell was modeled as a fluid drop of viscosity mu, bounded by a contractile cortex whose tension above a resting value was taken to be linearly dependent on surface area expansion. The pipet negative pressure was first adjusted to an equilibrium value, corresponding to formation of a static hemispherical cap into the pipet. This allowed computation, through Laplace's law, of the resting tension (tau 0), on the order of 3 x 10(-4) N/m. No difference in tau 0 was found between the different groups of cells studied (suspended, adherent for 5 min, spread for 0.5 h, and spread for 3 h). However, tau 0 was significantly decreased upon treatment of fibroblasts with inhibitors of actin polymerization or myosin function. Then, the pressure was set at 30 mmH2O above the equilibrium pressure. All cells showed a biphasic behavior: (1) a rapid initial entrance corresponding to an increase in surface area, which was used to extract an area expansion elastic modulus (K), in the range of 10(-2) N/m; this coefficient was found to increase up to 40% with cell spreading; (2) a more progressive penetration into the pipet, linear with time; this phase, attributed to viscous behavior of the cytoplasm, was used to compute the apparent viscosity (mu, in the range of 2-5 x 10(4) Pa s) which was found to increase by as much as twofold with cell spreading. In some experiments the basal force at the cell-microplate interface was quantitated with flexible microplates and found to be around 1 nN, in agreement with values calculated from the model. Taken together, our results indicate a stiffening of fibroblasts upon spreading, possibly correlated with structural organization of the cytoskeleton during this process. This study may help understand better the morphology of fibroblasts and their mechanical role in connective tissue integrity.

Acute hypocalcemia and erythropoiesis in the mouse.

Mice were made acutely hypocalcemic by injection of sodium oxalate. After the transient drop of plasma calcium marked changes in erythroblastic proliferation, number of erythroblasts and 59Fe kinetics were observed. The probable mechanism of this response that may reflect increased erythropoiesis is discussed.

Bacillary angiomatosis by Bartonella quintana in an HIV-infected patient.

Bacillary angiomatosis and bacillary peliosis are opportunistic infections caused by Bartonella henselae and Bartonella quintana, which occur in patients with late-stage infection. We report a case of bacillary angiomatosis in an HIV-infected patient with skin, bone, and probably liver involvement, The identification of the agent (B quintana ) was done by polymerase chain reaction in the skin specimen. The patient had complete regression of all lesions after a 6-month regimen of oral erythromycin.

Acting on actin: the electric motility assay.

We have developed a novel technique which allows one to direct the two dimensional motion of actin filaments on a myosin coated sheet using a weak electric field parallel to the plane of motion. The filament velocity can be increased or decreased, and even reversed, as a function of orientation and strength of the field. PMMA (poly(methylmethacrylate)) gratings, which act as rails for actin, allow one for the first time to explore three quadrants of the force velocity diagram. We discuss effective friction, duty ratio and stall force at different myosin densities. A discontinuity in the velocity force relationship suggests the existence of dynamical phase transition.