ana ani - Profile on Academia.edu (original) (raw)

Papers by ana ani

Research paper thumbnail of Effects of collagen membranes enriched with in vitro-differentiated N1E-115 cells on rat sciatic nerve regeneration after end-to-end repair

Journal of Neuroengineering and Rehabilitation, 2010

Peripheral nerves possess the capacity of self-regeneration after traumatic injury but the extent... more Peripheral nerves possess the capacity of self-regeneration after traumatic injury but the extent of regeneration is often poor and may benefit from exogenous factors that enhance growth. The use of cellular systems is a rational approach for delivering neurotrophic factors at the nerve lesion site, and in the present study we investigated the effects of enwrapping the site of end-to-end rat sciatic nerve repair with an equine type III collagen membrane enriched or not with N1E-115 pre-differentiated neural cells. After neurotmesis, the sciatic nerve was repaired by end-to-end suture (End-to-End group), end-to-end suture enwrapped with an equine collagen type III membrane (End-to-EndMemb group); and end-to-end suture enwrapped with an equine collagen type III membrane previously covered with neural cells pre-differentiated in vitro from N1E-115 cells (End-to-EndMembCell group). Along the postoperative, motor and sensory functional recovery was evaluated using extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. After 20 weeks animals were sacrificed and the repaired sciatic nerves were processed for histological and stereological analysis. Results showed that enwrapment of the rapair site with a collagen membrane, with or without neural cell enrichment, did not lead to any significant improvement in most of functional and stereological predictors of nerve regeneration that we have assessed, with the exception of EPT which recovered significantly better after neural cell enriched membrane employment. It can thus be concluded that this particular type of nerve tissue engineering approach has very limited effects on nerve regeneration after sciatic end-to-end nerve reconstruction in the rat.

Research paper thumbnail of Hepcidin, transferrin (exon 7), and hemochromatosis genotyping suggests that haplotype block analysis is the best strategy for predicting iron deficiency phenotype in women

Nutrition Research, 2007

Hepcidin, transferrin (exon 7), and hemochromatosis genotyping suggests that haplotype block anal... more Hepcidin, transferrin (exon 7), and hemochromatosis genotyping suggests that haplotype block analysis is the best strategy for predicting iron deficiency phenotype in women ☆

Research paper thumbnail of Determinants of cognitive function in childhood: A cohort study in a middle income context

BMC Public Health, 2008

Background: There is evidence that poverty, health and nutrition affect children's cognitive deve... more Background: There is evidence that poverty, health and nutrition affect children's cognitive development. This study aimed to examine the relative contributions of both proximal and distal risk factors on child cognitive development, by breaking down the possible causal pathways through which poverty affects cognition. This cohort study collected data on family socioeconomic status, household and neighbourhood environmental conditions, child health and nutritional status, psychosocial stimulation and nursery school attendance. The effect of these on Wechsler Pre-School and Primary Scale of Intelligence scores at five years of age was investigated using a multivariable hierarchical analysis, guided by the proposed conceptual framework. Results: Unfavourable socioeconomic conditions, poorly educated mother, absent father, poor sanitary conditions at home and in the neighbourhood and low birth weight were negatively associated with cognitive performance at five years of age, while strong positive associations were found with high levels of domestic stimulation and nursery school attendance. Children's cognitive development in urban contexts in developing countries could be substantially increased by interventions promoting early psychosocial stimulation and preschool experience, together with efforts to prevent low birth weight and promote adequate nutritional status.

Research paper thumbnail of Quality of past performance: Impact on consumers’ responses to service failure

Marketing Letters, 2007

The conceptual model developed in this paper for the airline industry examines the relationship b... more The conceptual model developed in this paper for the airline industry examines the relationship between quality of past service performance and consumers’ responses to service failures (causal attributions, emotions and satisfaction). The empirical results obtained indicate that for those consumers with higher perceptions of quality the causes underlying service failures are seen as less stable and less controllable by the firm than the causes identified by consumers with lower perceptions of quality. Attributions about the failure not only influence satisfaction directly but also moderate the effect of quality on satisfaction. We also analyse the mediating effect of negative emotions on the relationship between service failure attributions and consumer satisfaction.

Research paper thumbnail of A positive antinuclear antibody test predicts for a poor response to initial steroid therapy in adults with idiopathic thrombocytopenic purpura

Annals of Hematology, 2008

Adult idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disease that may be ass... more Adult idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disease that may be associated with other autoimmune disorders and a positive antinuclear antibody (ANA). This pilot study aimed to determine the clinical significance of a positive ANA test on the presentation and response to steroids. The medical records of 46 patients aged 15 years or older who were diagnosed with ITP at King Abdullah University Hospital from January, 2004 to December, 2006 were retrospectively analyzed. ANA results were available for 41 patients, and only 10 patients had a positive test. The study showed no association between the ANA and any of the patients’ characteristics at presentation. This included the age, sex, presence of autoimmune diseases, a family history of autoimmune diseases, platelet count, hemoglobin level, and erythrocyte sedimentation rate (ESR). It is interesting to note that the mean platelet count after 2 weeks of steroids was 99,323 per cu/ml in patients with a negative ANA, and 32,800 per cu/ml in those with a positive ANA (P = 0.006). The difference in mean platelet count between positive and negative ANA-tested patients remained significant after adjusting for sex, age, and ESR (P = 0.001). Also, patients with a positive ANA were 6.25 times more likely of not achieving a complete response defined as a platelet count of 100,000 per cu/ml or more for a minimum of 3 months after discontinuation of therapy. In conclusion, the ANA test could be a useful screening test that predicts initial response to steroid therapy. Patients who test positive are expected to have lower response and should be monitored closely.

Research paper thumbnail of One-two descriptor

Journal of Mathematical Chemistry, 2010

In this paper, we introduce the one-two descriptor. The one-two descriptors is the sum of the ver... more In this paper, we introduce the one-two descriptor. The one-two descriptors is the sum of the vertex contributions such that each pendant vertex contributes 1, each vertex of degree two adjacent to pendant vertex contributes 2, and each vertex of degree higher than two also contributes 2. We test this descriptor on the benchmark data set of the octane isomers proposed by the International Academy of Mathematical Chemistry. We show that this descriptor is a good predictor of the heat capacity at P constant (CP) and of the total surface area (TSA). Linear model predictions for both these properties are better then predictions of any of the benchmark descriptors proposed by International Academy of Mathematical Chemistry. Linear model predictions of TSA are also better then predictions of any of Adriatic descriptors, while linear model predictions of CP are not as good as predictions by Adriatic descriptor called inverse sum lordeg index. We also analyze the mathematical properties of this descriptor and we find tight upper and lower bounds in the families of the trees with n vertices and the chemical trees with n vertices.

Research paper thumbnail of Characterization of retrotransposon sequences expressed in inflorescences of apomictic and sexual Paspalum notatum plants

Sexual Plant Reproduction

Apomixis, an asexual mode of reproduction through seeds, holds much promise for agricultural adva... more Apomixis, an asexual mode of reproduction through seeds, holds much promise for agricultural advances. However, the molecular mechanisms underlying this trait are still poorly understood. We previously isolated several transcripts representing novel sequences differentially expressed in reproductive tissues of sexual and apomictic plants. Here, we report the characterization of two of these unknown RNA transcripts (experimental codes N17 and N22). Since original fragments showed no significant homologies to sequences at databases, preliminary genomic PCR experiments were carried out to discard possible contaminations. RACE extension on flanking regions provided longer sequences for the candidates and additional related transcripts, which revealed similarity to LTR retrotransposons carrying short transduplicated segments of protein-coding genes. Interestingly, some transduplicated segments corresponded to genes previously associated with apomictic development. Gene copy number estimations revealed a moderate representation of the elements in the genome, with significantly increased numbers in a sexual genotype with respect to an apomictic one. Genetic mapping of N17 showed that a copy of this particular element was located onto Paspalum notatum linkage group F3c, at a central non-recombinant region resembling a centromere. Expression analysis showed an increased activity of N17 and N22 sense strands in ovules of the sexual genotypes. A retrotransposon-specific differential display analysis aimed at detecting related sequences allowed the identification of a complex family, with the majority of its members represented in the sexual genotype. Our results suggest that these elements could be participating in regulatory pathways related to apomixis and sexuality.

Research paper thumbnail of Measurement of autoantibodies using multiplex methodology in patients with systemic lupus erythematosus

Journal of Immunological Methods, 2010

Autoantibodies are central to the diagnosis and assessment of systemic lupus erythematosus (SLE).... more Autoantibodies are central to the diagnosis and assessment of systemic lupus erythematosus (SLE). A recent technique for the measurement of autoantibodies utilizes addressable laser bead immunoassay technology (BioPlex 2200) which permits the simultaneous detection of multiple autoantibodies and improved efficiency due to the shorter time to perform the assay and low volume of test samples and reagents. In the current study we have compared this technique to more traditional measures of autoantibody detection. The clinical and laboratory data and stored serum samples from the enrollment visit into a long-term lupus registry at a single academic medical center were used. Sera were examined for a panel of autoantibodies using the BioPlex ANA screen. The results were compared to the historical data on autoantibody profiles using indirect immunofluorescence (IIF) and ELISA. The association with global and organ specific SLE disease activity (nephritis) was also examined. The study consisted of 192 patients who were predominantly female (87%) and Caucasian (91%) with mean disease duration of 8.8 years. The frequency of ANA and anti-dsDNA by IIF and ELISA was 81.3% and 46.6% respectively and was higher than that found with BioPlex (75.5% and 31.8%). The latter detected a higher proportion of patients with autoantibodies to Sm (7.5% vs 16.7%), RNP (21.8% vs 24.0%), Ro (37.4% vs 41.7) and La (13.9% vs 23.4%). Overall agreement between assays varied between 71.4% and 92.5%. Additional autoantibodies identified by BioPlex were anti-chromatin antibodies which were similar in frequency to anti-dsDNA antibodies (33.9% and 31.8% respectively). There was a low frequency of anti-ribosomal P (6.8%), anti-Scl-70 (5.2%), anti-centromere B (3.7%) and anti-Jo-1 (0.5%). Several autoantibodies revealed significant associations with SLEDAI scores but in a multivariate analysis the only autoantibodies that approached statistical significance were anti-Sm (p=0.094) measured by ELISA and anti-dsDNA (p=0.082) measured by BioPlex. There was no association between any of the autoantibodies regardless of the method of detection and cumulative organ damage scores. Fifty-three patients (27.6%) had lupus nephritis of which 17 (32%) had active nephritis at the time of autoantibody determination. There was no significant association between a positive ANA (IIF) and any autoantibodies detected by ELISA with either the cumulative occurrence of lupus nephritis or active nephritis. In contrast, there was an association between BioPlex detected anti-dsDNA with the cumulative occurrence of nephritis (p=0.074) which reached statistical significance with active nephritis at the time of antibody testing (p=0.012). This was confirmed by multivariate analysis (p=0.047). These results suggest reasonable agreement between the detection of lupus autoantibodies by ELISA and BioPlex. The latter demonstrated a better correlation with lupus nephritis.

Research paper thumbnail of High frequency of Anti-CagA antibodies in adult dyspeptic patients and asymptomatic blood donors from Nigeria

High frequency of Anti-CagA antibodies in adult dyspeptic patients and asymptomatic blood donors from Nigeria

Gastroenterology, 2000

Research paper thumbnail of Lactic acid and biosurfactants production from hydrolyzed distilled grape marc

Process Biochemistry, 2007

Acid hydrolysis of distilled grape marc, an useless agricultural residue from wineries, was carri... more Acid hydrolysis of distilled grape marc, an useless agricultural residue from wineries, was carried out using dilute sulfuric acid (1-5%) at several reaction times and 130 8C, in order to obtain monomeric sugars which after supplementation with corn steep liquor (10 g/L) and yeast extract (10 g/L) were used to carry out the fermentation into lactic acid by Lactobacillus pentosus without detoxification stage. Xylose was the main sugar generated followed by glucose and arabinose. Possible inhibitor compounds such as acetic acid liberated from acetyl groups, and furfural and hydroxymethylfurfural generated by sugars dehydration, were produced as degradation byproducts. The hydrolysis stage was optimized by using an incomplete factorial design where the independent variables were the percentage of catalyzer, the reaction time and the temperature. The optima conditions in terms of xylose concentration were 3.3% H 2 SO 4 , 125 min and 130 8C, but due to the high furfural concentration, two other conditions using lower reaction times (30 and 77.5 min) were also selected to assay the fermentation. Although any condition was feasible to fully utilize the relatively broad spectra of sugars released by the acid hydrolysis, under the shorter reaction time the best results were achieved (Q P = 0.476 g/L h; Y P/S = 0.71 g/g) which represents a theoretical yield of 97%. Furthermore, L. pentosus produced 4.8 mg/L of intracellular biosurfactants, measured as biosurfactin, representing a yield of 0.60 mg of intracellular biosurfactant per g of sugars consumed. #

Research paper thumbnail of Effects of collagen membranes enriched with in vitro-differentiated N1E-115 cells on rat sciatic nerve regeneration after end-to-end repair

Journal of Neuroengineering and Rehabilitation, 2010

Peripheral nerves possess the capacity of self-regeneration after traumatic injury but the extent... more Peripheral nerves possess the capacity of self-regeneration after traumatic injury but the extent of regeneration is often poor and may benefit from exogenous factors that enhance growth. The use of cellular systems is a rational approach for delivering neurotrophic factors at the nerve lesion site, and in the present study we investigated the effects of enwrapping the site of end-to-end rat sciatic nerve repair with an equine type III collagen membrane enriched or not with N1E-115 pre-differentiated neural cells. After neurotmesis, the sciatic nerve was repaired by end-to-end suture (End-to-End group), end-to-end suture enwrapped with an equine collagen type III membrane (End-to-EndMemb group); and end-to-end suture enwrapped with an equine collagen type III membrane previously covered with neural cells pre-differentiated in vitro from N1E-115 cells (End-to-EndMembCell group). Along the postoperative, motor and sensory functional recovery was evaluated using extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. After 20 weeks animals were sacrificed and the repaired sciatic nerves were processed for histological and stereological analysis. Results showed that enwrapment of the rapair site with a collagen membrane, with or without neural cell enrichment, did not lead to any significant improvement in most of functional and stereological predictors of nerve regeneration that we have assessed, with the exception of EPT which recovered significantly better after neural cell enriched membrane employment. It can thus be concluded that this particular type of nerve tissue engineering approach has very limited effects on nerve regeneration after sciatic end-to-end nerve reconstruction in the rat.

Research paper thumbnail of Hepcidin, transferrin (exon 7), and hemochromatosis genotyping suggests that haplotype block analysis is the best strategy for predicting iron deficiency phenotype in women

Nutrition Research, 2007

Hepcidin, transferrin (exon 7), and hemochromatosis genotyping suggests that haplotype block anal... more Hepcidin, transferrin (exon 7), and hemochromatosis genotyping suggests that haplotype block analysis is the best strategy for predicting iron deficiency phenotype in women ☆

Research paper thumbnail of Determinants of cognitive function in childhood: A cohort study in a middle income context

BMC Public Health, 2008

Background: There is evidence that poverty, health and nutrition affect children's cognitive deve... more Background: There is evidence that poverty, health and nutrition affect children's cognitive development. This study aimed to examine the relative contributions of both proximal and distal risk factors on child cognitive development, by breaking down the possible causal pathways through which poverty affects cognition. This cohort study collected data on family socioeconomic status, household and neighbourhood environmental conditions, child health and nutritional status, psychosocial stimulation and nursery school attendance. The effect of these on Wechsler Pre-School and Primary Scale of Intelligence scores at five years of age was investigated using a multivariable hierarchical analysis, guided by the proposed conceptual framework. Results: Unfavourable socioeconomic conditions, poorly educated mother, absent father, poor sanitary conditions at home and in the neighbourhood and low birth weight were negatively associated with cognitive performance at five years of age, while strong positive associations were found with high levels of domestic stimulation and nursery school attendance. Children's cognitive development in urban contexts in developing countries could be substantially increased by interventions promoting early psychosocial stimulation and preschool experience, together with efforts to prevent low birth weight and promote adequate nutritional status.

Research paper thumbnail of Quality of past performance: Impact on consumers’ responses to service failure

Marketing Letters, 2007

The conceptual model developed in this paper for the airline industry examines the relationship b... more The conceptual model developed in this paper for the airline industry examines the relationship between quality of past service performance and consumers’ responses to service failures (causal attributions, emotions and satisfaction). The empirical results obtained indicate that for those consumers with higher perceptions of quality the causes underlying service failures are seen as less stable and less controllable by the firm than the causes identified by consumers with lower perceptions of quality. Attributions about the failure not only influence satisfaction directly but also moderate the effect of quality on satisfaction. We also analyse the mediating effect of negative emotions on the relationship between service failure attributions and consumer satisfaction.

Research paper thumbnail of A positive antinuclear antibody test predicts for a poor response to initial steroid therapy in adults with idiopathic thrombocytopenic purpura

Annals of Hematology, 2008

Adult idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disease that may be ass... more Adult idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disease that may be associated with other autoimmune disorders and a positive antinuclear antibody (ANA). This pilot study aimed to determine the clinical significance of a positive ANA test on the presentation and response to steroids. The medical records of 46 patients aged 15 years or older who were diagnosed with ITP at King Abdullah University Hospital from January, 2004 to December, 2006 were retrospectively analyzed. ANA results were available for 41 patients, and only 10 patients had a positive test. The study showed no association between the ANA and any of the patients’ characteristics at presentation. This included the age, sex, presence of autoimmune diseases, a family history of autoimmune diseases, platelet count, hemoglobin level, and erythrocyte sedimentation rate (ESR). It is interesting to note that the mean platelet count after 2 weeks of steroids was 99,323 per cu/ml in patients with a negative ANA, and 32,800 per cu/ml in those with a positive ANA (P = 0.006). The difference in mean platelet count between positive and negative ANA-tested patients remained significant after adjusting for sex, age, and ESR (P = 0.001). Also, patients with a positive ANA were 6.25 times more likely of not achieving a complete response defined as a platelet count of 100,000 per cu/ml or more for a minimum of 3 months after discontinuation of therapy. In conclusion, the ANA test could be a useful screening test that predicts initial response to steroid therapy. Patients who test positive are expected to have lower response and should be monitored closely.

Research paper thumbnail of One-two descriptor

Journal of Mathematical Chemistry, 2010

In this paper, we introduce the one-two descriptor. The one-two descriptors is the sum of the ver... more In this paper, we introduce the one-two descriptor. The one-two descriptors is the sum of the vertex contributions such that each pendant vertex contributes 1, each vertex of degree two adjacent to pendant vertex contributes 2, and each vertex of degree higher than two also contributes 2. We test this descriptor on the benchmark data set of the octane isomers proposed by the International Academy of Mathematical Chemistry. We show that this descriptor is a good predictor of the heat capacity at P constant (CP) and of the total surface area (TSA). Linear model predictions for both these properties are better then predictions of any of the benchmark descriptors proposed by International Academy of Mathematical Chemistry. Linear model predictions of TSA are also better then predictions of any of Adriatic descriptors, while linear model predictions of CP are not as good as predictions by Adriatic descriptor called inverse sum lordeg index. We also analyze the mathematical properties of this descriptor and we find tight upper and lower bounds in the families of the trees with n vertices and the chemical trees with n vertices.

Research paper thumbnail of Characterization of retrotransposon sequences expressed in inflorescences of apomictic and sexual Paspalum notatum plants

Sexual Plant Reproduction

Apomixis, an asexual mode of reproduction through seeds, holds much promise for agricultural adva... more Apomixis, an asexual mode of reproduction through seeds, holds much promise for agricultural advances. However, the molecular mechanisms underlying this trait are still poorly understood. We previously isolated several transcripts representing novel sequences differentially expressed in reproductive tissues of sexual and apomictic plants. Here, we report the characterization of two of these unknown RNA transcripts (experimental codes N17 and N22). Since original fragments showed no significant homologies to sequences at databases, preliminary genomic PCR experiments were carried out to discard possible contaminations. RACE extension on flanking regions provided longer sequences for the candidates and additional related transcripts, which revealed similarity to LTR retrotransposons carrying short transduplicated segments of protein-coding genes. Interestingly, some transduplicated segments corresponded to genes previously associated with apomictic development. Gene copy number estimations revealed a moderate representation of the elements in the genome, with significantly increased numbers in a sexual genotype with respect to an apomictic one. Genetic mapping of N17 showed that a copy of this particular element was located onto Paspalum notatum linkage group F3c, at a central non-recombinant region resembling a centromere. Expression analysis showed an increased activity of N17 and N22 sense strands in ovules of the sexual genotypes. A retrotransposon-specific differential display analysis aimed at detecting related sequences allowed the identification of a complex family, with the majority of its members represented in the sexual genotype. Our results suggest that these elements could be participating in regulatory pathways related to apomixis and sexuality.

Research paper thumbnail of Measurement of autoantibodies using multiplex methodology in patients with systemic lupus erythematosus

Journal of Immunological Methods, 2010

Autoantibodies are central to the diagnosis and assessment of systemic lupus erythematosus (SLE).... more Autoantibodies are central to the diagnosis and assessment of systemic lupus erythematosus (SLE). A recent technique for the measurement of autoantibodies utilizes addressable laser bead immunoassay technology (BioPlex 2200) which permits the simultaneous detection of multiple autoantibodies and improved efficiency due to the shorter time to perform the assay and low volume of test samples and reagents. In the current study we have compared this technique to more traditional measures of autoantibody detection. The clinical and laboratory data and stored serum samples from the enrollment visit into a long-term lupus registry at a single academic medical center were used. Sera were examined for a panel of autoantibodies using the BioPlex ANA screen. The results were compared to the historical data on autoantibody profiles using indirect immunofluorescence (IIF) and ELISA. The association with global and organ specific SLE disease activity (nephritis) was also examined. The study consisted of 192 patients who were predominantly female (87%) and Caucasian (91%) with mean disease duration of 8.8 years. The frequency of ANA and anti-dsDNA by IIF and ELISA was 81.3% and 46.6% respectively and was higher than that found with BioPlex (75.5% and 31.8%). The latter detected a higher proportion of patients with autoantibodies to Sm (7.5% vs 16.7%), RNP (21.8% vs 24.0%), Ro (37.4% vs 41.7) and La (13.9% vs 23.4%). Overall agreement between assays varied between 71.4% and 92.5%. Additional autoantibodies identified by BioPlex were anti-chromatin antibodies which were similar in frequency to anti-dsDNA antibodies (33.9% and 31.8% respectively). There was a low frequency of anti-ribosomal P (6.8%), anti-Scl-70 (5.2%), anti-centromere B (3.7%) and anti-Jo-1 (0.5%). Several autoantibodies revealed significant associations with SLEDAI scores but in a multivariate analysis the only autoantibodies that approached statistical significance were anti-Sm (p=0.094) measured by ELISA and anti-dsDNA (p=0.082) measured by BioPlex. There was no association between any of the autoantibodies regardless of the method of detection and cumulative organ damage scores. Fifty-three patients (27.6%) had lupus nephritis of which 17 (32%) had active nephritis at the time of autoantibody determination. There was no significant association between a positive ANA (IIF) and any autoantibodies detected by ELISA with either the cumulative occurrence of lupus nephritis or active nephritis. In contrast, there was an association between BioPlex detected anti-dsDNA with the cumulative occurrence of nephritis (p=0.074) which reached statistical significance with active nephritis at the time of antibody testing (p=0.012). This was confirmed by multivariate analysis (p=0.047). These results suggest reasonable agreement between the detection of lupus autoantibodies by ELISA and BioPlex. The latter demonstrated a better correlation with lupus nephritis.

Research paper thumbnail of High frequency of Anti-CagA antibodies in adult dyspeptic patients and asymptomatic blood donors from Nigeria

High frequency of Anti-CagA antibodies in adult dyspeptic patients and asymptomatic blood donors from Nigeria

Gastroenterology, 2000

Research paper thumbnail of Lactic acid and biosurfactants production from hydrolyzed distilled grape marc

Process Biochemistry, 2007

Acid hydrolysis of distilled grape marc, an useless agricultural residue from wineries, was carri... more Acid hydrolysis of distilled grape marc, an useless agricultural residue from wineries, was carried out using dilute sulfuric acid (1-5%) at several reaction times and 130 8C, in order to obtain monomeric sugars which after supplementation with corn steep liquor (10 g/L) and yeast extract (10 g/L) were used to carry out the fermentation into lactic acid by Lactobacillus pentosus without detoxification stage. Xylose was the main sugar generated followed by glucose and arabinose. Possible inhibitor compounds such as acetic acid liberated from acetyl groups, and furfural and hydroxymethylfurfural generated by sugars dehydration, were produced as degradation byproducts. The hydrolysis stage was optimized by using an incomplete factorial design where the independent variables were the percentage of catalyzer, the reaction time and the temperature. The optima conditions in terms of xylose concentration were 3.3% H 2 SO 4 , 125 min and 130 8C, but due to the high furfural concentration, two other conditions using lower reaction times (30 and 77.5 min) were also selected to assay the fermentation. Although any condition was feasible to fully utilize the relatively broad spectra of sugars released by the acid hydrolysis, under the shorter reaction time the best results were achieved (Q P = 0.476 g/L h; Y P/S = 0.71 g/g) which represents a theoretical yield of 97%. Furthermore, L. pentosus produced 4.8 mg/L of intracellular biosurfactants, measured as biosurfactin, representing a yield of 0.60 mg of intracellular biosurfactant per g of sugars consumed. #