Activated protein C resistance in patients with arterial ischemic stroke

BACKGROUND

Activated C protein resistance (APC-R) has recently been reported to be a common cause of thrombophilia; it may be acquired or caused by a genetic defect (factor V Leiden mutation). It is clear that there is an association between APC-R and venous thrombosis. It has been suggested that there is a possible relationship of APC-R with arterial ischemic stroke (IS), but case-control studies have not given enough clues for considering APC-R as a main risk factor.

OBJECTIVES

To assess the incidence of APC-R in patients with IS of several ethiologies in Buenos Aires.

PATIENTS AND METHODS

Seventy-two patients with IS were assessed for signs or symptoms of previous clinical thrombophilia and the presence of vascular risk factors (RF). They were searched for APC-R (COATEST, APC resistance-V, with a predilution of the samples) test. Determinations were carried out between 1 to 4 months after the ischemic episode. The plasma of 50 healthy control subjects (blood donors) was used as controls.

RESULTS

None of the patients had signs of previous thrombophilia; 57 (79.2%) had RF for IS, and 3 (4.2%) had APC-R (all of them with RF). One subject in the control group (2%) showed a low APC response (1/50). The occurrence of APC-R among patients with stroke was not significantly higher when compared with the occurrence of APC-R among the control subjects.

CONCLUSIONS

In the present series, the incidence of factor V Leiden related APC-R in the group with IS was similar to the healthy population. Other risk factors were associated in patients showing APC-R.

First principles NMR calculations of phenylphosphinic acid C6H5HPO(OH): assignments, orientation of tensors by local field experiments and effect of molecular motion

The complete set of NMR parameters for (17)O enriched phenylphosphinic acid C(6)H(5)HP( *)O(*OH) is calculated from first principles by using the Gauge Including Projected Augmented Wave (GIPAW) approach [C.J. Pickard, F. Mauri, All-electron magnetic response with pseudopotentials: NMR chemical shifts, Phys. Rev. B 63 (2001) 245101/1-245101/13]. The analysis goes beyond the successful assignment of the spectra for all nuclei ((1)H, (13)C, (17)O, (31)P), as: (i) the (1)H CSA (chemical shift anisotropy) tensors (magnitude and orientation) have been interpreted in terms of H bonding and internuclear distances. (ii) CSA/dipolar local field correlation experiments have allowed the orientation of the direct P-H bond direction in the (31)P CSA tensor to be determined. Experimental and calculated data were compared. (iii) The overestimation of the calculated (31)P CSA has been explained by local molecular reorientation and confirmed by low temperature static (1)H-->(31)P CP experiments.

Bone mineral density in women with non-metastatic breast cancer: Effect of intravenous bisphosphonates given before adjuvant therapies

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Background: Adjuvant therapies shown survival improve of non-metastatic breast cancer (NMBC) patients, but they also decrease bone mineral density (BMD). Bisphosphonates are effective agents for the management of osteoporosis. Intravenous zoledronate, which is approved for the treatment of malignant hypercalcemia, multiple myeloma, and skeletal metastases, can suppress bone resorption and are often considered first-line therapy for the treatment of osteoporosis. We have analyzed the effects of chemotherapy on BMD of women with NMBC who received before adjuvant therapies intravenous bisphosphonates (zoledronic acid). Methods: We prospectively studied the effects of a single intravenous zoledronic acid dose (4 mg), on BMD of 74 women with NMBC (stage I-III), administred previous to the adjuvant therapies. The patients were referred to the Medical Oncology Service of University Hospital of Canary Islands between 2003 y 2006. Lumbar and hip BMD (g/cm2) was measured at diagnosis and after chemotherapy. The results were compared with a group of 80 patients with NMBC who received adjuvant therapy without intravenous bisphosphonates. Results: Breast cancer patients the median age was 52 ± 10 years old and the body mass index was 28,2 ± 5.5 kg/m2. At baseline there were not differences in BMD between the group that received bisphosphonates and the group with only chemotherapy at any of lumbar or femoral bone sites. In our study, the BMD after chemotherapy and intravenous bisphosphonates (n=74) significantly increased at femoral neck (0.805 ± 0.01, 0,826± 0.12; p=0.002) and trochanter (0.709 ± 0.01, 0.724 ± 0.01; p=0.002) and remained stable at lumbar, intertrochanter, total hip and Ward’s triangle; whether the group without bisphosphonates significantly decreased at lumbar (1.014 ± 0; 0.995 ± 0, p=0.0001), trochanter (0.701± 0; 0.690 ± 0, p=0,046), intertrochanter (1,095 ± 0; 1.078 ± 0, p=0.0001) and total hip (0,924 ± 0; 0.915 ± 0, p=0.046) areas (table). Conclusions: Women with NMBC are affected by early bone loss after adjuvant chemotherapy. Bisphosphonates intravenous (zoledronic acid) given before adjuvant therapy might be an effective treatment for this bone loss, increasing BMD or remaining stable.

No significant financial relationships to disclose.

Non-surgical management of intracranial subdural hematoma complicating spinal anesthesia

We report the case of a 29 year-old woman who presented a symptomatic intracranial subdural hematoma developing shortly after spinal anesthesia. The patient was fully conscious at clinical onset, and thus we treated her conservatively with an epidural autologous blood patch and close neurological observation. Given the clinical improvement the possibility of surgery was discauded in agreement with the neurosurgical team. Most cases of subdural hematoma appearing after spinal anesthesia are treated with surgery. In the present case the subdural hemorrhage was detected at our hospital 20 days after the anesthetic procedure, and given the excellent state of consciousness, we choosed a conservative management.

High prevalence of syphilis-HIV co-infection at four hospitals of the city of Buenos Aires, Argentina

A cross-sectional anonymous study of 261 STD (sexually transmitted diseases) outpatients and 288 outpatients from other hospital departments was conducted at four major city hospitals in Buenos Aires. High prevalence of human immunodeficiency virus (HIV) (14.5%) and syphilis (30.2%) was noted. Fifty-two persons were diagnosed with both HIV and syphilis. Of the 87 HIV cases observed, 52 (59.7%) were co-infected with syphilis. Stratified analysis by gender showed that the prevalence of HIV, syphilis and HIV/syphilis co-infection was significantly (p < 0.001) higher in men than women (HIV: 20.1% vs. 4.6%; syphilis: 39.3% vs. 17.4%; co-infection: 13.6% vs. 1.7%). Integrated HIV/STD intervention programs and more effective surveillance are required in Argentina.

Bienzyme sensors based on novel polymethylferrocenyl dendrimers

Amperometric bienzyme electrodes with horseradish peroxidase (HRP) and glucose oxidase (GOx) co-immobilized on polymethylferrocenyl dendrimers deposited onto platinum electrodes have been used for determination of the hydrogen peroxide produced by the oxidase during the enzymatic reaction. The redox dendrimers consist of flexible poly(propylenimine) dendrimer cores functionalised with octamethylferrocenyl units. The effects of dendrimer generation, the thickness of the dendrimer layer, substrate concentration, interferences, and reproducibility on the response of the sensors were investigated. The new bienzyme biosensors respond to substrate at work potential values between 200 and 50 mV (vs. SCE), have good sensitivity, and are resistant to interferences. Figure.

Characteristics of the injury environment in far-side crashes

The population of occupants in far-side crashes that are documented in the US National database (NASS/CDS) was studied. The annual number of front seat occupants with serious or fatal injuries in far-side planar and rollover crashes was 17,194. The crash environment that produces serious and fatal injuries to belted front seat occupants in planar far-side crashes was investigated in detail. It was found that both the change in velocity and extent of damage were important factors that relate to crash severity. The median severity for crashes with serious or fatal injuries was a lateral delta-V of 28 kph and an extent of damage of CDC 3.6. Vehicle-to-vehicle impacts were simulated by finite element models to determine the intrusion characteristics associated with the median crash condition. These simulations indicated that the side damage caused by the IIHS barrier was representative of the damage in crashes that produce serious injuries in far-side crashes. Occupant simulations of the IIHS barrier crash at 28 kph showed that existing dummies lack biofidelity in upper body motion. The analysis suggested test conditions for studying far-side countermeasures and supported earlier studies that showed the need for an improved dummy to evaluate safety performance in the far-side crash environment.

Lectin typing of five medically important Candida species

This study reports the patterns of agglutination of 93 clinical Candida isolates by 14 commercial lectins. The isolates were of the species Candida albicans (55), C. tropicalis (12), C. guilliermondii (10). C. glabrata (eight) and C. parapsilosis (eight). Hundred percent of isolates were agglutinated, at least, by a panel of three lectins: Canavalia ensiformis (ConA), Lens culinaris (LCA) and Pisum sativum (PSA), all of them with alpha-D-mannose specificity. In addition, another panel of three lectins could distinguish between C. glabrata, C. tropicalis and C. albicans. Lectin typing may be of potential value for taxonomic and epidemiological studies of yeasts in clinical laboratories.

Cobaltocenium-functionalized poly(propylene imine) dendrimers: redox and electromicrogravimetric studies and AFM imaging

The first four generations of cobaltocenium-functionalized, diaminobutane-based poly(propylene imine) dendrimers DAB-dend-Cb,(PFb)x (x = 4, 8, 16, and 32; Cb=[Co(eta5-C5H4CONH)(eta5-C5H5)] (1-4) have been synthesized and characterized. The redox activity of the cobaltocenium centers in 1-4 has been characterized by using cyclic voltammetry and the electrochemical quartz-crystal microbalance (EQCM). All of the dendrimers exhibit reversible redox chemistry associated with the cobaltocenium/cobaltocene redox couple. Upon reduction. the dendrimers exhibit a tendency to electrodeposit onto the electrode surface, which is more pronounced for the higher generations. Pt and glassy carbon electrodes could be modified with films derived from 1-4,exhibiting a well-defined and persistent electrochemical response. EQCM measurements show that the dendrimers adsorb, at open circuit, onto platinum surfaces at monolayer or submonolayer coverage. Cathodic potential scanning past -0.75 V at which the cobaltocenium sites are reduced, gave rise to the electrodeposition of multilayer equivalents of the dendrimers. The additional material gradually desorbs upon re-oxidation so that only a monolayer equivalent remains on the electrode surface. Changes in film morphology as a function of dendrimer generation and surface coverage were studied by using admittance measurements of the quartz-crystal resonator on the basis of its electrical equivalent circuit, especially in terms of its resistance parameter. In general, we find that films of the lower dendrimer generation 1 behave rigidly, whereas those of the higher generation 4 exhibit viscoelastic behavior with an intermediate behavior being exhibited by 2 and 3. Using tapping-mode atomic force microscopy (AFM). we have been able to obtain molecularly resolved images of dendrimer 4 adsorbed on a Pt(111) electrode.

Molecular cloning and developmental expression of AtGR1, a new growth-related Arabidopsis gene strongly induced by ionizing radiation

Screening for mRNAs that accumulate after DNA damage induced by ionizing radiation, we have isolated a 2.0-kb cDNA coding for a new Arabidopsis PEST-box protein named AtGR1 (A. thaliana gamma response 1) with an expression profile similar to that observed for several plant cell cycle-related proteins. Using an anti-AtGR1 antibody, we have shown that the AtGR1 protein is expressed at basal levels in mitotically dividing cells (meristematic tissues and organ primordia) and at a strongly enhanced level in endoreduplicating cells (stipules, trichomes). Using transgenic Arabidopsis plants that express the GUS reporter gene under the control of the AtGR1 promoter, we have demonstrated that the observed AtGR1 protein distribution is due to the promoter activity. Our results suggest that basal AtGR1 levels are associated with progression through mitosis, whereas elevated intracellular levels of AtGR1 seem to induce changes between the S and M phases of the cell cycle that trigger somatic cells to enter the endoreduplication cycle. Ionizing radiation-induced rapid and dose-dependent accumulation of AtGR1 mRNA in cell cultures and plant tissues leads to tissue-specific accumulation of AtGR1 protein, best observed in ovules, which never undergo an endoreduplication cycle. It therefore appears that the radiation-induced transient AtGR1 accumulation reflects DNA damage-dependent transient cell cycle arrest before mitosis, which is necessary to accomplish DNA repair prior to chromosome segregation and cytokinesis.

Involvement of lipoxygenase-dependent production of fatty acid hydroperoxides in the development of the hypersensitive cell death induced by cryptogein on tobacco leaves

Lipid peroxidation was investigated in relation with the hypersensitive reaction in cryptogein-elicited tobacco leaves. A massive production of free polyunsaturated fatty acid (PUFA) hydroperoxides dependent on a 9-lipoxygenase (LOX) activity was characterized during the development of leaf necrosis. The process occurred after a lag phase of 12 h, was accompanied by the concomitant increase of 9-LOX activity, and preceded by a transient accumulation of LOX transcripts. Free radical-mediated lipid peroxidation represented 10% of the process. Inhibition and activation of the LOX pathway was shown to inhibit or to activate cell death, and evidence was provided that fatty acid hydroperoxides are able to mimic leaf necrotic symptoms. Within 24 h, about 50% of leaf PUFAs were consumed, chloroplast lipids being the major source of PUFAs. The results minimize the direct participation of active oxygen species from the oxidative burst in membrane lipid peroxidation. They suggest, furthermore, the involvement of lipase activity to provide the free PUFA substrates for LOX. The LOX-dependent peroxidative pathway, responsible for tissue necrosis, appears as being one of the features of hypersensitive programmed cell death.

Lectin typing of methicillin-resistant Staphylococcus aureus

This study reports the patterns of agglutination of 77 clinical isolates of methicillin-resistant Staphylococcus aureus by 32 commercially available lectins. Cell suspensions were not pre-treated. Each isolate was cultured on three media: Columbia blood agar, trypticase-soy agar and Chapman Stone agar. The lectins agglutinating each isolate varied widely depending on culture medium; only five isolates were agglutinated by the same set of lectins regardless of the culture medium used. Lectin typing could be a useful epidemiological tool, but it is necessary to standardise assay conditions (notably culture medium) to enable meaningful comparison of the results produced by different research groups or centres.

Study of some lymphocyte subset counts and cytokine levels in cryptococcosis associated with AIDS

Approximately 100 new cases per year of cryptococcosis in HIV+ patients are observed in Muñiz Hospital, 35% of them suffer a fatal outcome within the first four weeks after diagnosis in spite of treatment. Apparently there is not a useful parameter that allows a clear prediction of this early fatal outcome of the disease. The aim of this study is to determine some cytokine levels and several lymphocyte subpopulations counts in order to correlate these results with the evolution of the disease. Forty HIV+ patients suffering culture confirmed cryptococcosis were enrolled in this study, 8 HIV+ patients without cryptococcosis and 8 healthy individuals with negative serology for HIV were included as controls. The following determinations were done in all cases: CD3+, CD4+, CD8+, CD16+CD3-, CD19+ cell counts, IL-1; IL-12, TNFalpha in serum and TNFalpha in CSF. Ten cases with cryptococcosis and AIDS were controlled three months after treatment. The average of CD4+ and NK cell counts in patients before treatment were 22/microl and 90/microl respectively; IL-1 levels were higher in the patients than in the healthy control group, conversely IL-12 levels did not show significant differences in the three studied groups. Serum concentrations of TNFalpha were higher in patients than in the control group and were not modified after treatment, conversely antifungal medication diminished IL-1 concentration and remarkably increased NK cell counts. At the same time antigen levels in serum and CSF decreased. The results obtained seem to show that the immunological alterations observed in these patients are those characteristically exhibited in severe HIV disease and that some parameters such as CD8+ cell counts lower than 200/microl, less than 50 CD4+/microl, more than 50 pg/ml of TNF-alpha and serum capsular antigen titer higher than 1:5000 seem to predict a rapidly fatal course of infection.