A CFSE-based assay of proliferative response of lymphocytes to stimulation with dengue viruses

Dengue viruses (DENVs) are human pathogens that constitute a significant threat worldwide. Since they up-regulate MHC class I molecules; the cell-mediated immunity may play an important role in the defense against viruses. In this work, we tested a CFSE-based assay in determining proliferative response of lymphocytes isolated from mice or monkeys previously immunized with various DENV antigens to in vitro stimulation with DENVs. A positive proliferative response was obtained with lymphocytes of animals immunized with either live DENV-2 or its recombinant proteins. A similar result was also obtained with CD8+ T cells from mice immunized with live DENV-1 or DENV-2 following stimulation with homologous viruses. A comparison of the carboxyfluorescein diacetate succinimidyl ester (CFSE)-based and a 3H-thymidine incorporation-based assays of proliferative response of total lymphocytes showed a fair correlation of results of both assays. However, the CSFE-based assay offers in addition the determination of contribution of the CD8+ or other subsets of T cells to total proliferative response. These results represent the first and successful application of a CFSE-based assay to the evaluation of cell-mediated immunity to DENVs. This assay might be also exploited in testing candidate DENV vaccines.

[Cost-effectiveness analysis of a genetic screening program in the close relatives of Spanish patients with familial hypercholesterolemia]

INTRODUCTION AND OBJECTIVES

The aim was to assess the cost-effectiveness of a genetic screening program for first-degree relatives of patients with familial hypercholesterolemia (FH), followed by treatment when necessary, compared with the alternative of no screening.

METHODS

The cost-effectiveness analysis modeled the effect of statin treatment on individuals who were diagnosed with FH after genetic screening. The impact of uncertainty was evaluated using univariate probabilistic sensitivity analysis. The alternate strategy considered was no screening. In the cost-effectiveness analysis, the number of life-years gained (LYG) was regarded as the health outcome and the costs of screening, statin treatment, specialist consultations and hospital visits were all included. In addition, the expected value of perfect information was calculated as part of the sensitivity analysis.

RESULTS

In the base case, the incremental cost of the screening program for close relatives was 3423 euros per LYG. Although the sensitivity analysis gave a range of results, the conclusions were not affected by changes in the parameters considered. The screening program was found to be better than the alternative considered at a probability level of 95% if the acceptable level of health-care costs was at least 7400 euros per LYG.

CONCLUSIONS

This analysis indicates that a genetic screening program, supplemented by treatment, for the close relatives of individuals with FH is preferable to the alternative of no screening in terms of incremental cost-effectiveness.

Decline in the workload associated with the serodiagnosis of syphilis in a general hospital: 1994-2004

Syphilis re-emergence is a cause of concern. Our objective was to quantify the laboratory workload, incident cases and patient follow-up that syphilis has generated for 11 years in a large teaching hospital. An ecologic study including all samples submitted for syphilis serodiagnosis at our hospital from January 1994 to December 2004 was undertaken. Our laboratory processed 58,832 samples for syphilis serodiagnosis. From 1994 to 2004, the number of samples submitted for syphilis testing dropped by 11% (95% confidence interval [CI] 10-12, p<0.001). Syphilis was diagnosed in 443 patients. The incidences were 11, 3 and 8 per 100,000 inhabitants/year in 1994, 2000 and 2004, respectively. Only 42% (185) of patients had repeat tests and in 79% (146) of cases, the 1-year follow-up data were missing. The median follow-up was 9 months (interquartile range [IQR] 3-26). We detected a reduction in the effort to detect syphilis, despite an increase in its incidence and the low cost of syphilis screening. Efforts should be intensified to improve physician compliance with syphilis screening and follow-up guidelines.

[Cost-effectiveness of managing familial hypercholesterolemia using atorvastatin-based preventive therapy]

INTRODUCTION AND OBJECTIVES

A cost-effectiveness model was developed to evaluate the efficiency of different preventive strategies in familial hypercholesterolemia (FH) in comparison with routine clinical practice (CP): atorvastatin monotherapy, 40 mg (A40) or 80 mg (A80, and atorvastatin combined with ezetimibe, 10 mg (A40+E10 or A80+E10).

METHODS

A longitudinal population model with a time horizon for life-expectancy was developed within the context of the Spanish public healthcare system. Life tables for the Spanish population (2002) were modified using the standardized mortality rate for individuals with FH. Effectiveness was expressed in life-years gained (LYG), after taking into account reductions for risk (ie, Framingham risk score) and cardiovascular mortality. The costs (in 2005 terms) of the intervention (CI) and care (CC) were discounted at 6%, while effects were discounted at 3%.

RESULTS

Routine CP, based on the Spanish FH registry: 1.97 LYG per patient vs. no treatment; CI euro5321, CC euro23,389. A40: 2.59 LYG; reduction in CC compared with CP 4.5%; total costs (TC) euro30 569. A80: 2.75 LYG; reduction in CC 6.4%; TC euro30 133. A40+E10: 3.38 LYG; reduction in CC 14.3%; TC euro36 104. A80+E10: 3.62 LYG; reduction in CC 17.6%; TC euro35 317. From most to least efficient strategy, the incremental cost-effectiveness per LYG compared with CP was: a) A80: euro1821; b) A40: euro3012; c) A80+E10: euro4021, and d) A40+E10: euro5250.

CONCLUSIONS

Preventive treatment of FH with atorvastatin was cost-effective. The greatest cost-effectiveness was obtained with atorvastatin monotherapy, 80 mg. The addition of ezetimibe could produce further benefits at an acceptable incremental cost.

Molecular characterization of the hemagglutinin-neuraminidase gene of porcine rubulavirus isolates associated with neurological disorders in fattening and adult pigs

"Blue eye disease" is a viral infection of swine endemic in Mexico, which produces fatal encephalitis accompanied by respiratory signs and corneal opacity in suckling piglets. An atypical blue eye disease outbreak presented high rates of neurological signs in fattening and adult pigs from 2000 to 2003. In order to identify the basis of increased neurovirulence, the hemagglutinin-neuraminidase (HN) gene of several porcine rubulavirus isolates were sequenced and compared with that of La Piedad Michoacan virus and other isolates that did not produce neurological disorders in weaned pigs. Nine amino acid mutations distinguished the high neurovirulent PAC6-PAC9 viruses, whereas five mutations characterized the low neurovirulent PAC2 and PAC3 viruses. HN protein three-dimensional models showed that the main conformation and functional domains were preserved, although substitutions A223T and A291D occurred in PAC2 and PAC3 viruses, as well as A511K and E514K presented in PAC6-PAC9 viruses considerably modified the properties of the HN protein surface. The increased positive charge of the HN protein of PAC6-PAC9 viruses seems to be associated with their increased neurovirulence.

Characterisation of levofloxacin-resistant clinical isolates of Streptococcus pyogenes in Bilbao, Spain

The resistance mechanisms and clonal relationship were determined for two Streptococcus pyogenes isolates with high-level resistance to levofloxacin as well as to other fluoroquinolones. DNA amplification and sequencing revealed a serine-81-->phenylalanine substitution in GyrA and a double substitution in ParC of serine-79-->phenylalanine and aspartic acid-91-->asparagine. Pulsed-field gel electrophoresis analysis and emm typing determined that both isolates were emm type 28 and were genetically indistinguishable.

Breast cancer experience in Uruguay: A 21-year follow up of 1,906 patients in the same institution

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Background: Breast cancer is the most common tumor arising in Uruguaian women accounting for 1,930 patients/year (adjusted incidence ratio 83.1/100,000) with 637 death/year (adjusted mortality ratio 24.1/100,000). Both incidence and mortality rank Uruguay at the top of the latinamerican countries ( IARC-GloboCan 2002). We are presenting our final results with 1,906 patients followed during a 21 year period in the biggest private Institution in our country (CENDIMA) and probably amongst all other latin-american countries. Methods: Although this study was initially designed to find a relationship between prognostic factors and survival parameters: OS (overall survival) and DFS (disease free survival) it also describes the epidemiological features of a big breast cancer population in the top ranked country for breast cancer incidence and mortality in Latin America. Statistical analysis was calculated with SPSS (11.0 version) and SAS (6.0 version) programs. OS and DFS results were obtained through Kaplan Meier method. Log rank test was implemented for univariate analysis and Cox proportional hazard rates were used for multivariate analysis. Results: The median age at diagnosis was 61.0 (SD 13.5). Ductal infiltrating carcinoma (DIC) accounted for more than 80% of patients and 56% were node negative (N0) patients at diagnosis. Stratification was: Stage 0: 8.6%, Stage I: 31.5%, Stage II: 41.8%, Stage III: 16.6%, Stage IV: 1.5%. For OS, the axillary status and hystologic grade showed the highest relative ratio (RR) value: 2.49 and 2.40. The nodal status was the main prognostic factor related to DFS with a 2.2 RR. The five and ten year survival rate was: 0.96 and 0.92 (stage I), 0.84 and 0.71 (stage II), 0.71 and 0.56 (stage III) and 0.39 and 0.29 (stage IV) respectively. Conclusions: This is the final analysis of our population in Uruguay representing the biggest report in breast pathology in a latin-american country with a long follow up period (more than 20 years). Our “good” survival results may reflect the initially low risk population at diagnosis (56% node negative, 40.1% stage 0-I ). Nodal status, histologic grade and staging at diagnosis were independent prognostic factors in univariate and multivariate analysis.

No significant financial relationships to disclose.

Immunohistochemical localization of hormones and peptides in the human pituitary cells in a case of hypercortisolism by ACTH secreting microadenoma

This study assesses the action of hypercortisolism on the hormone and peptide periadenoma region of removed ACTH-producing microadenoma. Our findings show that cortisol excess affects both ACTH and GH production, with no immunoreaction for these hormones. The remaining pituitary hormones (TSH, FSH and PRL) and POMC-derived peptides (betaEnd, alphaMSH and betaMSH) were not modified. Likewise, we observed pituitary immunoreactive cells for Neurotensin (NT), Intestinal vasoactive peptide (VIP), Substance P (SP) and Angiotensin-II (Ang-II). The colocalization demonstrated that NT was expressed in thyrotrope and gonadotrope cells, VIP in gonadotrope cells and SP in corticotrope cells. The results about Ang-II were inconclusive. On the other hand, immunoreaction for the NPY and Gal peptides were not present. In the adenomatous cells, the peptide NT is present in ACTH cells as well as SP. These results suggest a peptide regulation of pituitary cells in the pathological state that can differ between normal and tumoural cells of the same pituitary.

Balance sensory organization in children with profound hearing loss and cochlear implants

OBJECTIVES

(1) To determine the feasibility of the use of a modified postural control test under altered sensory conditions in children over 8 years of age, and (2) to assess how deaf children use sensory information for postural control when they have normal or abnormal vestibular responses, and if hearing input from a unilateral cochlear implant, changes their postural behavior.

PATIENTS

We selected 36 children, 8 to 11 years of age, with congenital or early-acquired profound sensorineural hearing loss, 13 of them with unilateral cochlear implantation and 22 normal-hearing children.

METHODS

The Postural Control (PC) test consists of a force platform with 2 stimulation paradigm conditions: (1) standing on the platform with opened eyes; (2) standing on foam placed on the force platform with closed eyes. Implanted children were tested with the implant turn on and turn off in this condition, in order to evaluate eventual change in the postural control parameters when they have hearing habilitation. The body center of pressure distribution area (COP) and the body sway velocity (SV) were the parameter to evaluate the postural control.

RESULTS

Deaf children were classified into two groups according with the vestibular responses: group A (n=28) Children with normal vestibular rotary responses; group B (n=8) children with hypoactive responses. Children in group A had diagnoses of syndromic and non-syndromic hereditary deafness, and children in group B had inner ear malformations, post-meningitis deafness, and one child had non-syndromic hereditary deafness with hypoactive vestibular response. In condition 1, when vestibular, somatosensory and visual information were enabled, the COP and SV values did not show any statistically significant differences between groups A, B and control. In condition 2, when visual information was removed and the somatosensory input strongly modified by standing on the foam, group B showed significant higher COP and SV values than groups A and control (p<0.05). In addition, the scalograms by wavelets of children in group B had higher amplitudes increasing the sway frequencies contents up to 3 Hz, not allowing them to maintain the up right stance in similar stimulation than in condition. Implanted children of the group A and B with the implant turn on, in the condition 2, did not show any significant difference in the SV, comparing when they had the implanted turn off. Group A p=0.395 and group B p=0.465 (Wilcoxon ranked test).

CONCLUSION

These findings allow us to confirm that this postural test can be performed in children over 8 years old. Also our results suggest that deaf children with associated hypoactive vestibular responses included in our study, despite the etiology of the deafness, primarily use visual and somatosensory information to maintain their postural control. Hearing habilitation with a unilateral cochlear implant has no effect on the observed sensory organization strategy.

Stomatal conductance of semi-natural Mediterranean grasslands: implications for the development of ozone critical levels

Intra-genus and intra-specific variation and the influence of nitrogen enrichment on net assimilation and stomatal conductance of some annual Trifolium species of Mediterranean dehesa grasslands were assessed under experimental conditions. Also gas exchange rates were compared between some Leguminosae and Poaceae species growing in the field in a dehesa ecosystem in central Spain. The results showed that the previously reported different O3 sensitivity of some Trifolium species growing in pots does not seem to be related to different maximum g(s) values. In addition, no clear differences on gas exchange rates could be attributed to Leguminosae and Poaceae families growing in the field, with intra-genus variation being more important than differences found between families. Further studies are needed to increase the database for developing a flux-based approach for setting O3 critical levels for semi-natural Mediterranean species.