Effects of exercise training on autonomic modulation and mood symptoms in patients with obstructive sleep apnea.

We evaluated the effects of exercise training (ET) on the profile of mood states (POMS), heart rate variability, spontaneous baroreflex sensitivity (BRS), and sleep disturbance severity in patients with obstructive sleep apnea (OSA). Forty-four patients were randomized into 2 groups, 18 patients completed the untrained period and 16 patients completed the exercise training (ET). Beat-to-beat heart rate and blood pressure were simultaneously collected for 5 min at rest. Heart rate variability (RR interval) was assessed in time domain and frequency domain (FFT spectral analysis). BRS was analyzed with the sequence method, and POMS was analyzed across the 6 categories (tension, depression, hostility, vigor, fatigue, and confusion). ET consisted of 3 weekly sessions of aerobic exercise, local strengthening, and stretching exercises (72 sessions, achieved in 40±3.9 weeks). Baseline parameters were similar between groups. The comparisons between groups showed that the changes in apnea-hypopnea index, arousal index, and O2 desaturation in the exercise group were significantly greater than in the untrained group (P<0.05). The heart rate variability and BRS were significantly higher in the exercise group compared with the untrained group (P<0.05). ET increased peak oxygen uptake (P<0.05) and reduced POMS fatigue (P<0.05). A positive correlation (r=0.60, P<0.02) occurred between changes in the fatigue item and OSA severity. ET improved heart rate variability, BRS, fatigue, and sleep parameters in patients with OSA. These effects were associated with improved sleep parameters, fatigue, and cardiac autonomic modulation, with ET being a possible protective factor against the deleterious effects of hypoxia on these components in patients with OSA.

Effects of exercise training on autonomic modulation and mood symptoms in patients with obstructive sleep apnea

We evaluated the effects of exercise training (ET) on the profile of mood states (POMS), heart rate variability, spontaneous baroreflex sensitivity (BRS), and sleep disturbance severity in patients with obstructive sleep apnea (OSA). Forty-four patients were randomized into 2 groups, 18 patients completed the untrained period and 16 patients completed the exercise training (ET). Beat-to-beat heart rate and blood pressure were simultaneously collected for 5 min at rest. Heart rate variability (RR interval) was assessed in time domain and frequency domain (FFT spectral analysis). BRS was analyzed with the sequence method, and POMS was analyzed across the 6 categories (tension, depression, hostility, vigor, fatigue, and confusion). ET consisted of 3 weekly sessions of aerobic exercise, local strengthening, and stretching exercises (72 sessions, achieved in 40±3.9 weeks). Baseline parameters were similar between groups. The comparisons between groups showed that the changes in apnea-hypopnea index, arousal index, and O2 desaturation in the exercise group were significantly greater than in the untrained group (P<0.05). The heart rate variability and BRS were significantly higher in the exercise group compared with the untrained group (P<0.05). ET increased peak oxygen uptake (P<0.05) and reduced POMS fatigue (P<0.05). A positive correlation (r=0.60, P<0.02) occurred between changes in the fatigue item and OSA severity. ET improved heart rate variability, BRS, fatigue, and sleep parameters in patients with OSA. These effects were associated with improved sleep parameters, fatigue, and cardiac autonomic modulation, with ET being a possible protective factor against the deleterious effects of hypoxia on these components in patients with OSA.

Financial impact of sarcopenia on hospitalization costs.

BACKGROUND/OBJECTIVES: This study aims to increase knowledge regarding the association of sarcopenia with hospitalization costs among a wide-ranging sample of adult hospitalized patients. SUBJECTS/METHODS: A prospective study was conducted among hospitalized adult patients. Sarcopenia was identified according to the European Working Group on Sarcopenia in Older People, as low muscle mass, assessed by bioelectrical impedance analysis and low muscle function evaluated by handgrip strength. Hospitalization cost was calculated for each patient based on discharge diagnosis-related group codes and determined on the basis of a relative weight value. Costs were defined as the percentage of deviation from the cost of a patient with a relative weight equal to one. Multivariable linear regression models were performed to identify the factors independently associated with hospitalization costs. RESULTS: A total of 656 hospitalized patients aged ⩾18 years (24.2% sarcopenic) composed the study sample. Sarcopenia increased hospitalization costs by [euro ]1240 (95% confidence interval (CI): [euro ]596-1887) for patients aged <65 years and [euro ]721 (95% CI: [euro ]13-1429) for patients aged ⩾65 years. Sarcopenic overweight was related to an increase in hospitalization costs of [euro ]884 (95% CI: [euro ]295-1476). CONCLUSIONS: Sarcopenia is independently related to hospitalization costs. This condition is estimated to increase hospitalization costs by 58.5% for patients aged <65 years and 34% for patients aged ⩾65 years.

Comparative analysis of undernutrition screening and diagnostic tools as predictors of hospitalisation costs.

BACKGROUND: Undernutrition is associated with higher hospitalisation costs. The present study aims (i) to explore whether undernutrition status at hospital admission, as evaluated by different screening and diagnostic tools, can predict patient's hospitalisation costs and (ii) to provide an updated economic analysis of undernutrition burden. METHODS: A prospective study was conducted in a university hospital. Participants' (n = 637) nutritional risk was evaluated within 72 h of admission using the Nutritional Risk Screening (NRS-2002) and the Malnutrition Universal Screening Tool ('MUST'). Undernutrition status was determined by Academy of Nutrition and Dietetics (AND) and American Society for Parenteral and Enteral Nutrition (ASPEN) recommended clinical characteristics and by the Patient Generated Subjective Global Assessment (PG-SGA). The hospitalisation cost was calculated for each inpatient using the diagnosis-related group system. Multivariable linear regression analysis was conducted to identify predictors of hospitalisation costs via percentage deviation from the mean cost, after adjustment for patients' characteristics and comorbidities. RESULTS: Undernutrition risk according to NRS-2002 and high undernutrition risk according to 'MUST' increased patient's costs, respectively, by 21.1% [95% confidence interval (CI) = 9.0-33.2%] and 28.8% (95% CI = 13.7-39.9%). Severe undernutrition by AND-ASPEN recommended clinical characteristics and by PG-SGA was also associated with higher hospitalisation costs, respectively 19.4% (95% CI = 7.3-31.5%) and 27.5% (95% CI = 14.0-41.1%). The cost of a nutritionally-at-risk or undernourished patient is between €416 (95% CI = €156-675) and €617 (95% CI = €293-855) higher than the average of the respective diagnosis-related group. CONCLUSIONS: Undernutrition is a predictor of hospitalisation costs, increasing costs by between 19% and 29%. Undernutrition screening tools have an ability for predicting hospitalisation costs similar to that of diagnostic tools. An updated analysis of undernutrition associated costs was provided, highlighting the economic burden of undernutrition.

Sarcopenia and length of hospital stay.

BACKGROUND/OBJECTIVES: We aimed to quantify the association of sarcopenia with length of hospital stay (LOS) and to identify factors associated with sarcopenia among hospitalized patients. SUBJECTS/METHODS: A total of 655 patients composed the study sample. A longitudinal study was conducted in a University Hospital. Sarcopenia was defined, according to European Consensus criteria, as low muscle mass (bioelectrical impedance analysis) and low muscle function (handgrip strength). Logistic regression, Kaplan-Meier and Cox adjusted proportional hazards methods were used. LOS was determined from the date of hospital admission and discharge home (event of interest). RESULTS: Participants were aged 18 to 90 years (24.3% sarcopenic). Factors associated with sarcopenia were male gender, age ⩾65 years, moderate or severe dependence, undernutrition and being admitted to a medical ward. Sarcopenic patients presented a lower probability of being discharged home (hazard ratio (HR), 95% confidence interval (CI)=0.71, 0.58-0.86). However, after stratifying for age groups, this effect was visible only in patients aged <65 years (HR, 95% CI= 0.66, 0.51-0.86). Moreover, sarcopenic overweight or obese patients presented a higher probability of being discharged home (HR, 95% CI=0.78, 0.61-0.99) than nonoverweight sarcopenic patients (HR, 95% CI=0.63, 0.48-0.83). CONCLUSIONS: Being male, age ⩾65 years, presenting dependence, being undernourished and admitted to a medical ward were factors associated with sarcopenia among hospitalized adult patients. Sarcopenia is independently associated with longer LOS, although this association is stronger for patients aged <65 years. Moreover, sarcopenic overweight was associated with a higher probability of discharge home than nonoverweight sarcopenia.

Handgrip strength measurement as a predictor of hospitalization costs.

BACKGROUND: Undernutrition status at hospital admission is related to increased hospital costs. Handgrip strength (HGS) is an indicator of undernutrition, but the ability of HGS to predict hospitalization costs has yet to be studied. OBJECTIVE: To explore whether HGS measurement at hospital admission can predict patient's hospitalization costs. SUBJECTS/METHODS: A prospective study was conducted in a university hospital. Inpatient's (n=637) HGS and undernutrition status by Patient-Generated Subjective Global Assessment were ascertained. Multivariable linear regression analysis, computing HGS quartiles by sex (reference: fourth quartile, highest), was conducted in order to identify the independent predictors of hospitalization costs. Costs were evaluated through percentage deviation from the mean cost, after adjustment for patients' characteristics, disease severity and undernutrition status. RESULTS: Being in the first or second HGS quartiles at hospital admission increased patient's hospitalization costs, respectively, by 17.5% (95% confidence interval: 2.7-32.3) and 21.4% (7.5-35.3), which translated into an increase from €375 (58-692) to €458 (161-756). After the additional adjustment for undernutrition status, being in the first or second HGS quartiles had, respectively, an economic impact of 16.6% (1.9-31.2) and 20.0% (6.2-33.8), corresponding to an increase in hospitalization expenditure from €356 (41-668) to €428 (133-724). CONCLUSIONS: Low HGS at hospital admission is associated with increased hospitalization costs of between 16.6 and 20.0% after controlling for possible confounders, including undernutrition status. HGS is an inexpensive, noninvasive and easy-to-use method that has clinical potential to predict hospitalization costs.

Handgrip strength cutoff values for undernutrition screening at hospital admission.

BACKGROUND/OBJECTIVES: There is increasing evidence showing that handgrip strength (HGS) is an indicator of nutrition status and a promising undernutrition screening tool. However, HGS cutoff values for inpatient undernutrition screening remain to be studied. The present study aims to define gender- and age-specific HGS cutoff values for undernutrition screening of hospitalized patients at admission. SUBJECTS/METHODS: A cross-sectional study was conducted in a university hospital. Gender- and age-specific receiver operating characteristic curves were constructed to evaluate the performance of HGS for correctly screening undernourished patients on the basis of their classification by Patient-Generated Subjective Global Assessment. Sensitivity, specificity, areas under the curves (AUCs) and positive likelihood ratios (LRs) were calculated. RESULTS: The study sample was composed of 712 participants between the ages of 18 and 91 years old, median (interquartile range) of 58 (22) years. For women, HGS cutoff values, sensitivities and specificities were as follows: 18-44 years, 20.2 kgf, 0.741 and 0.556; 45-64 years, 19.2 kgf, 0.795 and 0.522. For men, these values were as follows: 18-44 years, 41.7 kgf, 0.923 and 0.520; 45-64 years, 37.9 kgf, 0.817 and 0.402; ⩾65 years, 30.2 kgf, 0.736 and 0.567. The AUCs varied between 0.642 and 0.778 and LRs from 1.37 to 1.92. CONCLUSIONS: This study provides HGS cutoff values for men aged 18-91 years and for women aged 18-64 years.

Hand length as an alternative measurement of height.

BACKGROUND/OBJECTIVES: Despite the utmost importance of body height in evaluating nutritional status, it is not always possible to obtain its measurement and height may have to be estimated. The objective of the study was to formulate and cross-validate a regression equation to predict height using hand length measurement and also to determine if predicted height (PH) will lead to significant errors when used in body mass index (BMI) calculation. SUBJECTS/METHODS: A cross-sectional study was conducted using a consecutive sample of 465 inpatients (19-91 years), from a university hospital. Participants were randomly divided into a development sample of 311 individuals and a cross-validation one. A linear regression model was used to formulate the equation. Intraclass correlation coefficients (ICCs) for single measures and differences between measured height (MH) and PH and between BMI calculated with MH (BMI(MH)) and with PH (BMI(PH)) were determined. RESULTS: The regression equation for PH is: PH (cm)=80.400+5.122 × hand length (cm)--0.195 × age (years)+6.383 × gender (gender: women 0, men 1) (R=0.87, s.e. of the estimate=4.98 cm). MH and PH were strongly correlated, ICCs: 0.67-0.74 (P<0.001). Differences were small, mean difference±s.d., < or = -0.6±4.4 cm (P > or = 0.24). BMI(MH) and BMI(PH) were strongly correlated, ICCs: 0.94-0.96 (P<0.001). Differences were small, < or = 0.3±1.7 kg/m2 (P > or = 0.10). CONCLUSIONS: The formulated regression equation using hand length, age and gender provides a valid estimation of height and is useful in the clinical context. PH from this regression equation can be used in BMI calculations as misclassification is small.

Expression of Foxp3, CD25 and IL-2 in the B16F10 cancer cell line and melanoma is correlated with tumor growth in mice.

The forkhead box P3 (Foxp3) transcription factor is one of the most studied markers used to identify CD4+CD25+ regulatory T cells (Tregs), and has been identified as a key regulator in the development and function of Tregs. Foxp3 expression has been reported in a variety of solid human tumors, including melanoma. The aims of the present study were to analyze Foxp3 expression in B16F10 melanoma cells in vitro, to determine whether this expression was affected during tumor growth in a murine melanoma model and to correlate Foxp3 expression with CD25 expression, interleukin (IL)-2 production and tumor weight. Foxp3 expression was analyzed with quantitative (q)PCR, flow cytometry and confocal microscopy. CD25 expression was analyzed by flow cytometry, and cytokine production was measured by ELISA [IL-2, interferon (IFN)-γ, transforming growth factor (TGF)-ß and IL-10] and flow cytometry (IL-2, IFN-γ, IL-4 and IL-5). Foxp3 and CD25 expression was detected in the B16F10 cells in culture and in the intratumoral B16F10 cells. An increase in Foxp3 and CD25 expression was observed in a time-dependent manner during tumor growth at 7, 14 and 21 days. The production of the IL-2, IL-10, IFN-γ and TGF-ß cytokines was observed in the B16F10 cells and also detected in the tumoral microenvironment during tumor growth (7, 14 and 21 days). An increase in IL-2 and IL-10 production was observed, whereas IFN-γ production decreased in a time-dependent manner. The production of tumor necrosis factor (TNF)-α was not observed in culture, but was detected during tumor growth, whereas the production of IL-4 and IL-5 was not detected. These data showed a positive correlation between the expression of Foxp3, CD25 and IL-2 and tumor weight in murine melanoma. From these data, it may be suggested that Foxp3 participates in melanoma growth, the modulation of the IL-2, IFN-γ and TNF-α cytokines and CD25 expression, and that it also plays a possible role in immunosuppression.

Anatomical location for waist circumference measurement in older adults: a preliminary study.

BACKGROUND AND OBJECTIVE: Different anatomical locations for measuring waist circumference are described in the literature but the best anatomical location for measuring waist circumference in older adults has yet to be established. Thus, an exploratory study was developed to examine which waist circumference best explains abdominal fat mass in older adults. METHODS: Waist circumference was measured in the ten different anatomical locations from a sample of 51 older adults. The choice of which waist circumference measurement best associated with abdominal fat mass was evaluated with dual-energy X-ray absorptiometry (DXA) measurement of abdominal fat. RESULTS: Mean waist circumference values varied from 81.9 (standard deviation (SD): 8.7) cm and 91.5 (SD: 11.2) cm for women and between 95.7 (SD: 8.2) cm and 101.5 (SD: 10.4) cm for men, according to the different anatomical locations. The coefficients of determination of the linear regression model varied from 0.545 to 0.698 (p < 0.001) and the standardised coefficients varied from 0.738 and 0.836 (p < 0.001). The anatomical landmark situated 2.5 cm above the umbilicus was the waist circumference measurement that associated best with abdominal fat mass measured by DXA. CONCLUSION: This exploratory study contributes to the recognition that the anatomical location where the waist circumference measurement is taken gives considerably different results. The waist circumference measurement 2.5 cm above the umbilicus was the best surrogate measure of abdominal fat in this older adult's sample.

Accuracy of Siri and Brozek equations in the percent body fat estimation in older adults.

OBJECTIVE: To identify which equation, Siri or Brozek, based on the two compartment model, provides a more accurate conversion of body density (BD) in percent body fat (%BF) in a group of older adults. STUDY DESIGN: Cross-sectional study. SETTING: Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto. PARTICIPANTS: 60 older adults, aged 60-92 years. MEASUREMENTS: Skinfold thickness was used to estimate BD through Visser et al. prediction equation. The conversion of BD to %BF was done with Siri (%BF-Siri) and Brozek (%BF-Brozek) formulas and these determined values were both compared to Dual-Energy X-ray Absorptiometry (%BF-DXA) evaluations. RESULTS: A strong correlation between the %BF-DXA value and %BF-Siri (r=0.91, p < 0.001) and %BF-Brozek (r=0.91, p < 0.001) was found, although %BF-Siri and %BF-Brozek overestimated %BF-DXA (p < 0.001). The comparison of the %BF-Siri and %BF-Brozek mean values also revealed significant differences (p < 0.001). The %BF-Brozek reflects a better agreement than the %BF-Siri with %BF-DXA with respectively a mean difference of -4.0 %BF (limits of agreement = -10.9 to 2.9%) and -5.7 %BF (-12.6 to 1.2). The Bland and Altman plots confirmed that %BF-Brozek reflects a better agreement with %BF-DXA. CONCLUSION: The results of the present study show that the use of Brozek equation may correspond to a more accurate alternative than Siri equation for the conversion of BD in %BF in older adults.

Comparison of hand dynamometers in elderly people.

OBJECTIVE: Some dynamometers previously tested in healthy adults showed variable degrees of practicality, weight and ergonomics. More practical models could also be used as a more suitable tool in gerontological field and clinical studies. The purpose of the present study was to evaluate the reliability of the measurements and the performance of hand grip strength dynamometers in the elderly. STUDY DESIGN: Cross-sectional study. SETTING: A retirement home and a social day care centre for old people in Porto, Portugal. PARTICIPANTS AND MEASUREMENTS: The accuracy of four static grip strength dynamometers (Smedlay's Hand, Sammons Preston Rolyan Bulb, Eisenhut and the Jamar Hydraulic Hand) was first tested in laboratory. The grip strength of fifty-five elderly individuals 65-99 years was measured with the four dynamometers and the Jamar Hydraulic Hand which was used as the comparison dynamometer. RESULTS: The accuracy of the four dynamometers measurements compared to known forces was excellent (r > 0.96). A strong association between the measurements obtained by the Jamar Hydraulic and the other instruments evaluated was found (r > 0.77) but significant differences between the mean hand grip strength values evaluated with the Jamar Hydraulic and each one of the other dynamometers were found. The Bland and Altman plots confirmed that none of the three dynamometers reflects a good agreement with the Jamar Hydraulic. CONCLUSION: All four dynamometers showed excellent results regarding their laboratory tested accuracy. However, their application among elderly people rendered very different results. The Smedlay's results were closer to the Jamar Hydraulic, though none of these three dynamometers produced comparable results to the Jamar Hydraulic.

IMMUNEPOTENT CRP (bovine dialyzable leukocyte extract) adjuvant immunotherapy: a phase I study in non-small cell lung cancer patients.

BACKGROUND: IMMUNEPOTENT CRP is a mixture of low molecular weight substances, some of which have been shown to be capable of modifying the immune response. We evaluated the response and adjuvant effect of IMMUNEPOTENT CRP on non-small cell lung cancer (NSCLC) patients in a phase I clinical trial. METHODS: Twenty-four NSCLC patients were included in the study and divided into two groups. Group 1 received a conventional treatment of 5400 cGy external radiotherapy in 28 fractions and chemotherapy consisting of intravenous cisplatin (40 mg/m(2)) delivered weekly for 6 weeks. Group 2 received the conventional treatment plus IMMUNEPOTENT CRP (5 U) administered daily. We performed clinical evaluation by CT scan and radiography analysis, and determined the quality of life of the patients with the Karnofsky performance scale. A complete blood count (red and white blood cell tests), including flow cytometry analysis, blood work (alkaline phosphatase test) and a delayed-type hypersensitivity (DTH) skin test for PPD, Varidase and Candida were performed. RESULTS: The administration of IMMUNEPOTENT CRP induced immunomodulatory activity (increasing the total leukocytes and T-lymphocyte subpopulations CD4(+), CD8(+), CD16(+) and CD56(+), and maintaining DHT) and increased the quality of the patients' lives, suggesting immunologic protection against chemotherapeutic side-effects in NSCLC patients. DISCUSSION: Our results suggest the possibility of using IMMUNEPOTENT CRP alongside radiation and chemotherapy for maintaining the immune system and increasing the quality of life of the patients.

Bovine dialyzable leukocyte extract modulates AP-1 DNA-binding activity and nuclear transcription factor expression in MCF-7 breast cancer cells.

BACKGROUND: We have previously demonstrated that bovine dialyzable leukocyte extract (bDLE) induces death through an apoptosis mechanism in MCF-7 breast cancer cells. Depending on the cell type and stimulus, activating protein-1 (AP-1) has been shown to regulate cell proliferation and differentiation, the stress response, apoptosis and survival. It remains unknown whether AP-1 and other transcription factors are mechanisms by which bDLE induces cell death. METHODS: To determine whether bDLE modulates the AP-1 DNA binding and gene expression, MCF-7 breast cancer cells were treated with bDLE (0, 1, 5, 10 U) for 72 h and evaluated by electrophoretic mobility shift assay, reverse transcriptase-polymerase chain reaction and Western blot assays. RESULTS: bDLE induced inhibition of cell growth, suppressed the AP-1 DNA-binding activity, decreased c-Jun protein expression and modulated NFATx, NFATc, NFkappaB, c-Jun and c-Fos transcription factor gene expression in MCF-7 breast cancer cells. DISCUSSION: The present data indicate that bDLE can block the AP-1 DNA-binding activity and expression of several transcriptions factors in breast cancer cells, which will have great potential in improving cancer therapy.

Bovine dialyzable leukocyte extract modulates cytokines and nitric oxide production in lipopolysaccharide-stimulated human blood cells.

BACKGROUND: In the current study, we determined whether bovine dialyzable leukocyte extract (bDLE) modulates lipopolysaccharide (LPS)-induced nitric oxide and cytokine overproduction. METHODS: Human whole blood cells were treated with LPS (50 ng) + bDLE (1 U). RESULTS: The bDLE treatment decreased nitric oxide as well as TNF-alpha, IL-6 and IL-10 (P <0.01) cytokine production. In addition, it decreased TNF-alpha, IL-1beta and IL-6 mRNA expression and suppressed IL-10 and IL-12p40 mRNA expression, but did not modulate IL-8 mRNA expression in LPS-stimulated human blood cells. DISCUSSION: Our results suggest that bDLE may effectively modulate the fatal symptoms of hypotensive shock associated with endotoxin (LPS)-induced nitric oxide and cytokine production, and this may offer therapeutic potential for the treatment of endotoxic shock.

In vitro effects of bovine dialyzable leukocyte extract (bDLE) in cancer cells.

BACKGROUND: Bovine dialyzable leukocyte extract (bDLE) is a dialyzate of a heterogeneous mixture of low molecular weight substances released from disintegrated blood leukocytes or lymphoid tissue obtained from homogenized bovine spleen. The purpose of this study was to determine if bDLE had cytotoxic effects and modulated apoptosis gene expression in breast cancer cells. METHODS: The MCF-7, BT-474, MDA-MB-453, A-427, Calu-1, U937 and L5178Y cancer cell lines and PBMC human cells were treated with bDLE (0-0.66 U/mL) for 72 h. The bDLE effect on cell growth proliferation was evaluated by MTT assay, and the MCF-7 was evaluated by ethidium bromide-acridine orange staining; total DNA was evaluated for DNA fragmentation, and total RNA was isolated for p53, bag-1, c-myc, bim, bax, bcl-2 and bad mRNA expression. RESULTS: The bDLE had dose-dependent cytotoxic effects and demonstrated an IC50 at a dosage of 0.06 U/mL (P<0.05). The bDLE did not affect the viability of normal human PBMC. The bDLE induced DNA fragmentation at doses of 0.06 and 0.13 U/mL in MCF-7 breast cancer cells. The bDLE induced cytotoxic effects and suppressed the p53, bag-1, c-myc, bax, bcl-2, and bad mRNA expression that influences apoptosis in MCF-7 breast cancer cells. Bim mRNA expression was not detected. DISCUSSION: This may open up interesting prospects for the treatment of human breast cancer.

In vitro cytotoxicity testing of chitosan-containing polyelectrolyte complexes.

Two chitosan-containing polyelectrolyte complexes, chitosan-poly(acrylic acid) and chitosan-poly(styrenesulphonate), were synthesized by polymerizing acrylic acid and sodium styrenesulphonate in the presence of chitosan and chitosan hydrochloride, respectively. The complexes were studied by optical microscopy and tested for cytotoxicity by the Neutral Red uptake, Kenacid Blue R-Binding and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assays. The optical microscopy confirmed the differences in crystallinity and structure already found for the two polycomplexes by other characterization techniques. The cytoxicity tests showed different influences on the cell activity by the extracts of the two polyelectrolyte complexes. Such results were discussed and correlated to the different structures of the two materials.

Seroprevalence of HTLV-I/II in blood donors in Monterrey, Mexico.

The prevalence of antibodies against human T-cell lymphotrophic virus (HTLV-I/II) in blood donors from the city of Monterrey, Mexico was investigated. We found that 4 out of 1017 sera (0.39%) reacted against HTLV-I/II, as determined by a passive agglutination test (PA). However, none of PA-positive sera reacted to HTLV-I/II specific polypeptides as demonstrated by Western blot. These findings indicate that the population of Monterrey has very low or no seroprevalence for HTLV-I/II.

Cell cultures in the biocompatibility study of synthetic materials.

In vitro cytotoxicity (Neutral Red uptake, Kenacid Blue and MTT) and cytocompatibility (cell adhesion and proliferation) tests were applied to the biocompatibility study of a series of poly(ester-ether-ester) block copolymers of potential interest as biomaterials. Our results indicate that the copolymer extracts after 72 hours incubation with a 3T3 mouse fibroblast cell line do not induce significant toxic effects. Furthermore, human umbilical vein endothelial cells seeded on thin copolymer films show a normal pattern of growth. We conclude that thein vitro tests used are a valid instrument to evaluate the potential toxic action of synthetic materials on different cell compartments and that the tested materials seem to be promising for future applications in the field of biomedical devices.