Replacing soybean meal with microalgae biomass in diets with contrasting carbohydrate profile can reduce in vitro methane production and improve short-chain fatty acids production

The objective of this study was to evaluate the interaction of dietary carbohydrate profile and soybean meal (SBM) replacement with either Chlorella pyrenoidosa (CHL) or Spirulina platensis (SPI) on in vitro fermentation. This experiment was conducted as a randomized complete block design, with fermentation run (3 runs) considered as blocks. The treatments were arranged in a 2 × 5 factorial design, where the first factor was the carbohydrate profile, which was composed of diets containing 42.5% NDF and 26.8% starch (HF-LS) or 26.8% NDF and 40.6% starch (LF-HS) and the second factor was the protein source, in which a control diet (100% SBM), partial replacement of SBM with CHL (1/2 CHL) or SPI (1/2 SPI), or total replacement of SBM with CHL or SPI were used. All experimental diets were formulated to have 17% crude protein. The ruminal fluid was collected from 2 lactating Holstein cows, buffered with Van Soest medium at a ratio of 1:2 and added to serum bottles containing 0.50 g of the experimental diets. Bottles were incubated at 39°C for 24 and 48 h in triplicate; headspace pressure was measured, along with gas collection for methane (CH4) quantification at 0, 2, 4, 8, 16, 24, 36, and 48 h after incubation. The final medium was used to measure pH, ammonia, and volatile-fatty acid (VFA). After incubation, feed bags were recovered and used for estimation of degradability of DMD, NDF, and OMD. Statistical analysis was carried out using the MIXED procedure of SAS, with carbohydrate profile, protein source, assay, and its interactions as fixed effects, with run and bottle as random effects. Orthogonal contrasts were used to compare carbohydrate profile, algae species, carbohydrate profile × algae interaction, and linear and quadratic effects of SBM replacement with CHL or SPI. There was no interaction effect between carbohydrate profile and algae source. LF-HS improved gas production, degradability of nutrients, and VFA, mainly increasing the production of butyrate and propionate. When compared with CHL, SPI had a greater degradability of nutrients and branched VFA, along with reduction in total gas production and tended to reduce total CH4 yield. The replacement of SBM with algae linearly reduced the degradability of nutrients, along with a linear reduction in gas production. When replacement of SBM with only SPI was evaluated, SPI slightly reduced the degradability of nutrients; however, it promoted a linear reduction in CH4 yield, as well as reduction in CH4 yield by unit of degraded DM, NDF, and OM. In summary, there was no interaction of carbohydrate profile and protein source, which means that SBM replacement had a similar effect, regardless of dietary carbohydrate profile. Spirulina may be a more suitable algae source when compared with Chlorella due to the potential to reduce CH4.

Esketamine Augmentation in Treatment-Resistant Obsessive-Compulsive Disorder: A Retrospective Chart Review

OBJECTIVE

Converging evidence supports the role of the glutamate, an excitatory amino acid neurotransmitter, in the pathophysiology of obsessive-compulsive disorder (OCD). Ketamine and esketamine, both noncompetitive N -methyl- d -aspartate antagonists, have emerged as a promising medication for this psychiatric disorder, given its possible efficacy with faster onset and good tolerability. The purpose of this retrospective chart review is to evaluate whether unbiased clinical documentation supports formal clinical trials of esketamine for an OCD indication.

METHODS

A retrospective chart review of patients with treatment-resistant OCD receiving a single dose of esketamine (0.5mg/kg) added to standard therapy was conducted. The Yale-Brown Obsessive-Compulsive Scale and the Montgomery-Åsberg Depression Rating Scale were used to evaluate OCD and depressive symptoms respectively at baseline, 24 hours, and 7 days after esketamine administration. Descriptive statistics were used to analyze the data.

RESULTS

Eight subjects were identified in this retrospective chart review: esketamine was administered subcutaneously in 7 and intravenously in 1. One week after infusion, 25% of the sample met criteria for treatment response and 50% for partial response. Major depressive disorder was a comorbid diagnosis in 75% of the sample and 2 of these subjects showed a positive antidepressant response.

CONCLUSIONS

Our findings provide preliminary evidence that esketamine may reduce obsessive-compulsive symptoms in a subset of treatment-resistant OCD patients.

Irrigation with saline water in the cultivation of mini watermelon under phosphate fertilization

The objective of this study was to evaluate the water status, photosynthetic pigments, and photochemical efficiency of mini watermelon plants under salt stress and phosphate fertilization. The experiment was conducted in pots under greenhouse conditions in Pombal, PB, Brazil. The experimental design used was randomized blocks in a 5 × 4 factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.3, 1.3, 2.3, 3.3, and 4.3 dS m-1) and four doses of phosphorus (60, 80, 100, and 120% of the recommendation), with three replicates. The relative water content in the tissues decreased with the increase in ECw levels in all phosphorus doses, with decreases of 7.05, 7.81 and 8.83% per unit increase in ECw, in plants fertilized with 80, 100 and 120% P2O5. On the other hand, ECw levels increased electrolyte leakage, regardless of phosphorus doses of the recommendation. The synthesis of photosynthetic pigments and the quantum efficiency of photosystem II were inhibited by increasing water salinity from 0.3 dS m-1 in plants grown under phosphorus doses above 60% of the recommendation. Water salinity from 0.3 dS m-1 reduced chlorophyll b contents, initial, maximum, and variable fluorescence of mini watermelon plants, with a decrease of 11.86, 4.51, 4.53, and 4.54% per unit increment of ECw, respectively.

Arketamine for bipolar depression: Open-label, dose-escalation, pilot study

There are significantly fewer options for the treatment of bipolar depression than major depressive disorder, with an urgent need for alternative therapies. In this pilot study, we treated six subjects with bipolar disorder types I and II (according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria) who had been in a current depressive episode for at least four weeks. Four subjects were female (66.66%), and the mean age was 45.33 (±12.32). Subjects received adjunct treatment with two arketamine intravenous infusions one week apart-0.5 mg/kg first and then 1 mg/kg. The mean baseline Montgomery-Åsberg Depression Rating Scale (MADRS) total score was 36.66, which decreased to 27.83 24h after the first infusion of 0.5 mg/kg of arketamine (p = 0.036). In respect of the 1 mg/kg dose, the mean MADRS total score before the second infusion was 32.0, which dropped to 17.66 after 24h (p < 0.001). Arketamine appears to have rapid-acting antidepressant properties, consistent with previous animal studies on major depression. All individuals tolerated both doses, exhibiting nearly absent dissociation, and no manic symptoms. To the best of our knowledge, this pilot trial is the first to test the feasibility and safety of the (R)-enantiomer of ketamine (arketamine) for bipolar depression.

Brain-derived neurotrophic factor serum levels following ketamine and esketamine intervention for treatment-resistant depression: secondary analysis from a randomized trial

OBJECTIVES

Evidence suggests that ketamine's influence on brain-derived neurotrophic factor (BDNF) might be involved in its mechanism of rapid antidepressant action. We aimed to evaluate the differential impact of ketamine and esketamine on serum BDNF levels and its association with response patterns in treatment-resistant depression (TRD).

METHODS

Participants (n = 53) are from a randomized, double-blind clinical trial comparing the efficacy of single-dose ketamine (0.5mg/kg, n = 27) and esketamine (0.25mg/kg, n = 26) in TRD. Depression severity was assessed before and 24 hours, 72 hours, and 7 days after the intervention, using the Montgomery-Åsberg Depression Rating Scale (MADRS). Blood samples were collected before infusion, 24 hours, and 7 days afterwards.

RESULTS

There were no significant changes in BDNF levels at post-infusion evaluation points, and no difference in BDNF levels comparing ketamine and esketamine. Both drugs exhibited similar therapeutic effect. There was no association between BDNF levels and response to treatment or severity of depressive symptoms.

CONCLUSION

There was no significant treatment impact on BDNF serum levels - neither with ketamine nor esketamine - despite therapeutic response. These results suggest that ketamine or esketamine intervention for TRD has no impact on BDNF levels measured at 24 hours and 7 days after the infusion.

Arketamine as adjunctive therapy for treatment-resistant depression: A placebo-controlled pilot study

BACKGROUND

Racemic ketamine is a mixture of (R)-ketamine (arketamine) and (S)-ketamine (esketamine), with the latter regarded as the main isomer for antidepressant effects. However, preclinical data and one open-label human trial suggest arketamine might exert a more potent and longer-lasting antidepressant effect with fewer side effects. We aimed to explore the feasibility of a randomized controlled trial of arketamine for treatment-resistant depression (TRD) and to assess its efficacy and safety compared to placebo.

METHODS

This is a, randomized, double-blind, crossover, pilot trial (n = 10). All participants received saline and arketamine (0.5 mg/kg) with a one-week interval. Treatment effects were analyzed with a linear mixed effects (LME) model.

RESULTS

Our analysis suggested the presence of a carryover effect, so the main efficacy analysis was limited to the first week, which demonstrated a main effect of time (p = 0.038) but not for treatment (p = 0.40) or their interaction (p = 0.95). This indicates that depression improved over time, but without significant difference between arketamine and placebo. Analyzing the two weeks together, findings were the same. Dissociation and other adverse events were minimal.

LIMITATIONS

This was a pilot study with a small sample and underpowered.

CONCLUSIONS

Arketamine was not superior to placebo for TRD but demonstrated to be extremely safe. Our findings reinforce the importance of continuing studies with this drug, with better powered clinical trials, perhaps considering a parallel design with higher or flexible doses and repeated administrations.

Efficacy and safety of adjunctive therapy using esketamine or racemic ketamine for adult treatment-resistant depression: A randomized, double-blind, non-inferiority study

BACKGROUND

Ketamine and its enantiomers have recently been highlighted as one of the most effective therapeutic options in refractory depression. However, racemic ketamine and esketamine have not been directly compared. The aim of this study is to assess the efficacy and safety of esketamine compared to ketamine in patients with treatment-resistant depression (TRD).

METHODS

This is a randomized, double-blind, active-controlled, bicentre, non-inferiority clinical trial, with two parallel groups. Participants were randomly assigned to a 40-min single intravenous infusion of ketamine 0.5 mg/kg or esketamine 0.25 mg/kg. The primary outcome was the difference in remission rates for depression 24 h following intervention using the Montgomery-Åsberg Depression Rating Scale (MADRS), with a non-inferiority margin of 20%.

RESULTS

63 subjects were included and randomly assigned (29 to receive ketamine and 34 to receive esketamine). At 24 h, 24.1% of participants in the ketamine group and 29.4% of participants in the esketamine group showed remission, with a difference of 5.3% (95% CILB -13.6%), confirming non-inferiority. MADRS scores improved from 33 (SD 9.3) to 16.2 (SD 10.7) in the ketamine group and from 33 (SD 5.3) to 17.5 (SD 12.2) in the esketamine one, with a difference of -5.27% (95% CILB, -13.6). Both groups presented similar mild side effects.

CONCLUSIONS

Esketamine was non-inferior to ketamine for TRD 24 h following infusion. Both treatments were effective, safe, and well tolerated.

TRIAL REGISTRATION

Registered in Japan Primary Registries Network: UMIN000032355.

Comparative study of esketamine and racemic ketamine in treatment-resistant depression: Protocol for a non-inferiority clinical trial

INTRODUCTION

The use of ketamine as an option in the treatment of depressive disorder is growing rapidly, supported by numerous clinical trials attesting its efficacy and safety. Esketamine, the S (+) enantiomer of ketamine, is the most widely used form in the anesthetic environment in some countries, and new studies have shown that it may also be effective in depression and with better tolerability. However, no study so far has directly compared esketamine with racemic ketamine. Here we propose a protocol of a clinical trial to evaluate esketamine as a noninferior medication when compared to ketamine in the treatment of patients with treatment-resistant depression.

METHODS/DESIGN

This study protocol is for a randomized, controlled, double-blind noninferiority clinical trial. Subjects will be 18 years or older, with major depression characterized as treatment-resistant. Participants will receive a single infusion of either esketamine (0.25 mg/kg) or ketamine (0.5 mg/kg) over 40 minutes. The primary outcome will be the difference in remission rates between the 2 treatment arms at 24 and 72 hours after drug infusion. Secondary outcomes will include other timepoints, measurements of cognition, dissociation, and blood biomarkers.

DISCUSSION

A head-to-head study is the best way to evaluate whether the esketamine is in fact comparable to the racemic ketamine in terms of both efficacy and safety, and, if positive, it would be an initial step to increase the access to that type of treatment worldwide.

ETHICS AND DISSEMINATION

The study was approved by the local Institutional Review Board (University Hospital Professor Edgard Santos-Federal University of Bahia-Number: 46657415.0.0000.0049). Subjects will only participate after voluntarily agreeing and signing the Informed Consent Form. The study findings will be published in peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION

This trial has been registered in the Japan Primary Registries Network (JPRN): UMIN000032355, which is affiliated with the World Health Organization.

Successive pretreatment and enzymatic saccharification of sugarcane bagasse in a packed bed flow-through column reactor aiming to support biorefineries

A packed bed flow-through column reactor (PBFTCR) was used for pretreatment and subsequent enzymatic hydrolysis of sugarcane bagasse (SCB). Alkaline pretreatment was performed at 70 °C for 4h with fresh 0.3M NaOH solution or with liquor recycled from a previous pretreatment batch. Scheffersomyces stipitis NRRL-Y7124 was used for fermentation of sugars released after enzymatic hydrolysis (20 FPU g(-1) of dry SCB). The highest results for lignin removal were 61% and 52%, respectively, observed when using fresh NaOH or the first reuse of the liquor. About 50% of cellulosic and 57% of hemicellulosic fractions of pretreated SCBs were enzymatically hydrolyzed and the maximum ethanol production was 23.4 g L(-1) (ethanol yield of 0.4 gp gs(-1)), with near complete consumption of both pentoses and hexoses present in the hydrolysate during the fermentation. PBFTCR as a new alternative for SCB-biorefineries is presented, mainly considering its simple configuration and efficiency for operating with a high solid:liquid ratio.

Comparative IgG recognition of tick extracts by sera of experimentally infested bovines

Enzyme-linked immunosorbent assay (ELISA) and Western blot were used to investigate the pattern of antibody responses of six bovines infested twelve times with Rhipicephalus (Boophilus) microplus (Canestrini, 1887) (Acari: Ixodidae) (six heavy infestations followed by six light infestations) against salivary gland, gut and larvae extracts. During heavy infestations, bovine IgG levels were shown to be higher, and a decrease in the number and weight of ticks that completed the parasitic cycle was observed. The pattern changed starting from the seventh infestation, showing a decrease in IgG levels. An initial increase followed by a significant decrease in the proportion of ticks that completed the parasitic cycle was also observed from the seventh infestation. The number of molecules recognized by Western blot was higher from sera collected following heavy infestations than after light infestations, although a great variation in the profiles detected could be seen when the bovines were compared. These results indicate that IgG responses to different tick antigens may not be generally associated with bovine resistance, and that infestation levels modulate the magnitude of humoral responses and possibly the immune mechanisms in the natural acquisition of tick resistance.

Physical properties and biocompatibility of chitosan/soy blended membranes

Blends of polysaccharides and proteins are a source for the development of novel materials with interesting and tailorable properties, with potential to be used in a range of biomedical applications. in this work a series of blended membranes composed by chitosan and soy protein isolate was prepared by solvent casting methodology. in addition, cross-linking was performed in situ with glutaraldehyde solutions in the range 5x10(-3)-0.1 M. Furthermore, the influence of the composition and cross-linking on the degradation behaviour, water uptake and cell adhesion was investigated. The obtained results showed that the incorporation of chitosan, associated to network formation by cross linking, promoted a slight decrease of water absorption and a slower degradability of the membranes. Moreover, direct contact biocompatibility studies, with L929 cells, indicate that the cross-linking enhances the capability of the material to support cell growth.

A model of chronic IgE-mediated food allergy in ovalbumin-sensitized mice

Food allergy is most frequently the result of IgE-mediated hypersensitivity reactions. Here, we describe a chronic model in which some of the intestinal and systemic consequences of continuous egg white solution ingestion by ovalbumin-sensitized eight-week-old BALB/c mice, 6 animals per group, of both sexes, were investigated. There was a 20% loss of body weight that began one week after antigen exposure and persisted throughout the experiment (3 weeks). The sensitization procedure induced the production of anti-ovalbumin IgG1 and IgE, which were enhanced by oral antigen exposure (129% for IgG1 and 164% for IgE, compared to sensitization values). Intestinal changes were determined by jejunum edema at 6 h (45% Evans blue extravasation) and by a significant eosinophil infiltration with a peak at 48 h. By day 21 of continuous antigen exposure, histological findings were mild, with mast cell hyperplasia (100%) and increased mucus production (483%). Altogether, our data clearly demonstrate that, although immune stimulation was persistently occurring in response to continuous oral antigen exposure, regulatory mechanisms were occurring in the intestinal mucosa, preventing overt pathology. The experimental model described here reproduces the clinical and pathological changes of mild chronic food allergy and may be useful for mechanistic studies of this common clinical condition.

Xylitol production from sugarcane bagasse hydrolyzate in fluidized bed reactor. Effect of air flowrate

Cells of Candida guilliermondii immobilized onto porous glass spheres were cultured batchwise in a fluidized bed bioreactor for xylitol production from sugarcane bagasse hemicellulose hydrolyzate. An aeration rate of only 25 mL/min ensured minimum yields of xylose consumption (0.60) and biomass production (0.14 g(DM)/g(Xyl)), as well as maximum xylitol yield (0.54 g(Xyt)/g(Xyl)) and ratio of immobilized to total cells (0.83). These results suggest that cell metabolism, although slow because of oxygen limitation, was mainly addressed to xylitol production. A progressive increase in the aeration rate up to 140 mL/min accelerated both xylose consumption (from 0.36 to 0.78 g(Xyl)/L.h) and xylitol formation (from 0.19 to 0.28 g(Xyt)/L.h) but caused the fraction of immobilized to total cells and the xylitol yield to decrease up to 0.22 and 0.36 g(Xyt)/g(Xyl), respectively. The highest xylitol concentration (17.0 g(Xyt)/L) was obtained at 70 mL/min, but the specific xylitol productivity and the xylitol yield were 43% and 22% lower than the corresponding values obtained at the lowest air flowrate, respectively. The concentrations of consumed substrates and formed products were used in material balances to evaluate the xylose fractions consumed by C. guilliermondii for xylitol production, complete oxidation through the hexose monophosphate shunt, and cell growth. The experimental data collected at variable oxygen level allowed estimating a P/O ratio of 1.35 mol(ATP)/mol(O) and overall ATP requirements for biomass growth and maintenance of 3.4 mol(ATP)/C-mol(DM).

Preliminary kinetic characterization of xylose reductase and xylitol dehydrogenase extracted from Candida guilliermondii FTI 20037 cultivated in sugarcane bagasse hydrolysate for xylitol production

Candida guilliermondii FTI 20037 was cultured in sugarcane bagasse hydrolysate supplemented with 2.0 g/L of (NH4)2SO4, 0.1 g/L of CaCl2 x 2H2O, and 20.0 g/L of rice bran at 35 degrees C; pH 4.0; agitation of 300 rpm; and aeration of 0.4, 0.6, or 0.8 vvm. The high xylitol production (20.0 g/L) and xylose reductase (XR) activity (658.8 U/mg of protein) occurred at an aeration of 0.4 vvm. Under this condition, the xylitol dehydrogenase (XD) activity was low. The apparent K(M) for XR and XD against substrates and cofactors were as follows: for XR, 6.4 x 10(-2)M (xylose) and 9.5 x 10(-3) mM (NADPH); for XD, 1.6 x 10(-1)M (xylitol) and 9.9 x 10(-2) mM (NAD+). Because XR requires about 10-fold less xylose and cofactor than XD for the condition in which the reaction rate is half of the Vmax, some interference on the overall xylitol production by the yeast could be expected.

Immune and hormonal activity in adults suffering from depression

An association between depression and altered immune and hormonal systems has been suggested by the results of many studies. In the present study we carried out immune and hormonal measurements in 40 non-medicated, ambulatory adult patients with depression determined by CID-10 criteria and compared with 34 healthy nondepressed subjects. The severity of the condition was determined with the Hamilton Depression Rating Scale. Of 40 depressed patients, 31 had very severe and 9 severe or moderate depression, 29 (72.5%) were females and 11 (27.5%) were males (2.6:1 ratio). The results revealed a significant reduction of albumin and elevation of alpha-1, alpha-2 and beta-globulins, and soluble IL-2 receptor in patients with depression compared to the values obtained for nondepressed subjects (P<0.05). The decrease lymphocyte proliferation in response to a mitogen was significantly lower in severely or moderately depressed patients when compared to control (P<0.05). These data confirm the immunological disturbance of acute phase proteins and cellular immune response in patients with depression. Other results may be explained by a variety of interacting factors such as number of patients, age, sex, and the nature, severity and/or duration of depression. Thus, the data obtained should be interpreted with caution and the precise clinical relevance of these findings requires further investigation.

Metabolic study of the adaptation of the yeast Candida guilliermondii to sugarcane bagasse hydrolysate

Batch xylitol production from concentrated sugarcane bagasse hydrolysate by Candida guilliermondii was performed by progressively adapting the cells to the medium. Samples were analyzed to monitor sugar and acetic acid consumption, xylitol, arabitol, ethanol, and carbon dioxide production, as well as cell growth. Both xylitol yield and volumetric productivity remarkably increased with the number of adaptations, demonstrating that the more adapted the cells, the better the capacity of the yeast to reduce xylose to xylitol in hemicellulose hydrolysates. Substrate and product concentrations were used in carbon material balances to study in which way the different carbon sources were utilized by this yeast under microaerobic conditions, as well as to shed light on the effect of the progressive adaptation to the medium on its fermentative activity. Such a theoretical means allowed estimation for the first time of the relative contribution of each medium component to the formation of the main products of this fermentation system.

Inhibition of microbial xylitol production by acetic acid and its relation with fermentative parameters

Precipitated sugarcane bagasse hemicellulosic hydrolysate containing acetic acid was fermented by Candida guilliermondii FTI20037 under different operational conditions (pH 4.0 and 7.0, three aeration rates). At pH 7.0 and kLa of 10 (0.75 vvm) and 22.5/h (3.0 vvm) the acetic acid had not been consumed until the end of the fermentations, whereas at the same pH and kLa of 35/h (4.5 vvm) the acid was rapidly consumed and acetic acid inhibition was not important. On the other hand, fermentations at an initial pH of 4.0 and kLa of 22.5 and 35/h required less time for the acid uptake than fermentations at kLa of 10/h. The acetic acid assimilation by the yeast indicates the ability of this strain to ferment in partially detoxified medium, making possible the utilization of the sugarcane bagasse hydrolysate in this bio-process. The effects on xylitol yield and production are reported.

Effects of environmental conditions on xylose reductase and xylitol dehydrogenase production by Candida guilliermondii

The effects of environmental conditions, namely initial pH (2.5-7.0) and temperature (25 and 35 degrees C), on xylose reductase and xylitol dehydrogenase levels, as well as on xylitol production, were evaluated. Although the fermentative parameter values increased with an increase in pH and temperature (the maximum Yp/s and Qp were 0.75 g/g and 0.95 g/[L.h], respectively, both attained at pH 6.0, 35 degrees C), the highest xylose reductase activities (nearly 900 IU/mg of protein) were observed at an initial pH varying from 4.0 to 6.0. Xylitol dehydrogenase was favored by an increase in both initial pH and temperature of the medium. The highest xylitol dehydrogenase specific activity was attained at pH 6.5 and 35 degrees C (577 IU/mg of protein).

Effects of initial pH on biological synthesis of xylitol using xylose-rich hydrolysate

Sugarcane bagasse, an agricultural residue plentiful in Brazil, was utilized for xylitol production by a biotechnological process. A medium fermentation prepared with this xylose-rich biomass at an oxygen transfer volumetric coefficient of 10/h1 and different initial pH values was inoculated with cells of Candida guilliermondii FTI 20037. The maximum values of xylitol and cell volumetric productivities (Qp = 0.56 g/[L.h] and Qx = 0.11 g/[g.h]), xylitol yield factor (YP/S = 0.79 g/g), and xylose uptake rate (qs = 0.197 g/[g.h]) were attained at pH 7.0 without further pH control. The results show that the yeast performance was influenced by the pH, an important bioengineering parameter in this fermentation process.

Effect of the oxygen transfer coefficient on xylitol production from sugarcane bagasse hydrolysate by continuous stirred-tank reactor fermentation

The effect of the oxygen transfer coefficient on the production of xylitol by bioconversion of xylose present in sugarcane bagasse hemicellulosic hydrolysate using the yeast Candida guilliermondii was investigated. Continuous cultivation was carried out in a 1.25-L fermentor at 30 degrees C, pH 5.5, 300 rpm, and a dilution rate of 0.03/h, using oxygen transfer coefficients of 10, 20, and 30/h. The results showed that the microbial xylitol production (11 g/L) increased by 108% with the decrease in the oxygen volumetric transfer coefficient from 30 to 20/h. The maximum values of xylitol productivity (0.7 g/[L.h]) and yield (0.58 g/g) were obtained akLa 20/h.

Adaptation and reutilization of Candida guilliermondii cells for xylitol production in bagasse hydrolysate

The xylitol productivity increased by about 15% with the use of cells of Candida guilliermondii FTI 20037 previously recycled through four consecutive batch cultures and adapted to the sugar cane bagasse hemicellulosic hydrolysate. Furthermore, the more concentrated the hydrolysate, the more necessary was the adaptation of the cells, owing to the presence of toxic substances at high concentration which inhibited the xylose-xylitol conversion by the yeast.

Downstream processing for xylitol recovery from fermented sugar cane bagasse hydrolysate using aluminium polychloride

Xylitol, a sweetener comparable to sucrose, is anticariogenic and can be consumed by diabetics. This sugar has been employed successfully in many foods and pharmaceutical products. The discovery of microorganisms capable of converting xylose present in lignocellulosic biomass into xylitol offers the opportunity of producing this poliol in a simple way. Xylitol production by biotechnological means using sugar cane bagasse is under study in our laboratories, and fermentation parameters have already been established. However, the downstream processing for xylitol recovery is still a bottleneck on which there is only a few data available in the literature. The present study deals with xylitol recovery from fermented sugar cane bagasse hydrolysate using 5.2 g/l of aluminium polychloride associated with activated charcoal. The experiments were performed at pH 9, 50 degrees C for 50 min. The results showed that aluminium polychloride and activated charcoal promoted a 93.5% reduction in phenolic compounds and a 9.7% loss of xylitol from the fermented medium, which became more discoloured, facilitating the xylitol separation.

A Preliminary Information About Continuous Fermentation Using Cell Recycling for Improving Microbial Xylitol Production Rates(Scientific Note)

Xylitol is a sugar-alcohol with important technological properties, such as anticariogenicity, low caloric value, and negative dissolution heat. It can be used successfully in food formulations and pharmaceutical industries. Its production is therefore in great demand. Biotechnological xylitol production has several economic advantages in comparison with the conventional process based on the chemical reduction of xylose. The efficiency and the productivity of this fermentation chiefly depends on the microorganism and the process conditions employed. In this article a simple continuous culture with cell recycling was evaluated to enhance the capability of Candida guilliermondii FTI 20037 to produce xylitol. The fermentation was initiated batchwise by directly inoculating the grown seed culture in a 2-L bench-scale fermentor. Continuous feeding was begun at a dilution rate (D) of 0.060/h after the xylose concentration had completely consumed and the cell concentration was about 4.0 g/L. At a dilution rate of 0.060/h the xylitol concentration was about 15 g/L and increased by about 35%, whereas the dilution rate decreased by about 58%. Furthermore, the volumetric productivity, Qp, markedly depended on the dilution rate, diminishing by about 37% as D was changed from 0.060 to 0.025/h. These preliminary results show us that continuous fermentation with cell recycling is a good way to study the xylitol production by xylose-fermenting yeasts.

Biotechnological production of xylitol from agroindustrial residues. Evaluation of bioprocesses

Batch, fed-batch, and semicontinuous fermentation processes were used for the production of xylitol from sugarcane bagasse hemicellulosic hydrolysate. The best results were achieved by the semicontinuous fermentation process: a xylitol yield of 0.79 g/g with an efficiency of 86% and a volumetric productivity of 0.66 g/L/h.

Factors that affect the biosynthesis of xylitol by xylose-fermenting yeasts. A review

Xylitol is a sweetener with important technological properties like anticariogenicity, low caloric value, and negative dissolution heat. Because it can be used successfully in food formulations and pharmaceutical industries, its production is in great demand. Xylitol can be obtained by microbiological process, since many yeasts and filamentous fungi synthesize the xylose reductase enzyme, which catalyses the xylose reduction into xylitol as the first step in the xylose metabolism. The xylitol production by biotechnological means has several economic advantages in comparison with the conventional process based on the chemical reduction of xylose. The efficiency and the productivity of this fermentation chiefly depends upon the microorganism and the process conditions employed. In this mini-review, the most significant upstream parameters on xylitol production by biotechnological process are described.

Upstream parameters affecting the cell growth and xylitol production by Candida guilliermondii FTI 20037

The effects of yeast extract (0-10 g/l), methanol (0-10% v/v), acetic acid (0-1.0 g/l), furfural (0-0.5 g/l), glucose (0-30 g/l), inoculum age (15-70 h) and product concentration (18-230 g/l) on the xylose-xylitol conversion by Candida guilliermondii FTI 20037 were studied. The xylitol specific productivity increased about 35% at a yeast extract concentration of 1.0 g/l, whereas glucose showed a strong inhibitory effect on the xylitol production and a stimulating effect on the growth of C. guilliermondii. Methanol, acetic acid and furfural under the employed concentrations did not show any positive effect neither on the growth or on the xylose-xylitol conversion by the yeast. The inoculum age showed a strong influence on xylitol formation and the best fermentative parameters were attained using a 40-h inoculum age. A xylitol concentration in the fermentation medium higher than 80 g/l inhibited markedly the xylitol productivity by the yeast C. guilliermondii.

[Immediate and late results of the surgical treatment of the aneurysms and dissections of the ascending aorta]

PURPOSE

To report our experience and results with the surgical treatment of aortic aneurysms and dissections of the ascending aorta as well as the techniques that have been used.

METHODS

Between May 1982-May 1995, 54 patients were operated on and divided in two groups: group A was composed of 25 patients with aneurysms or chronic dissections of the ascending aorta. The Bentall and DeBonno procedure was performed in 18, five were submitted to prosthetic aortic graft associated with aortic valve replacement and two prosthetic aortic graft without aortic valve replacement. Group B had 29 patients with acute dissections of the ascending aorta (type A) who were submitted to 10 prosthetic graft alone, nine Bentall procedures, five prosthetic graft with aortic valve replacement, four aortic repair and one direct suture of the dissection. The survival curve was obtained by the Kaplan-Meier method.

RESULTS

Total hospital mortality rate was 13% and the late was 18.5%. Group A-immediate mortality rate was 8% (two patients): Low cardiac output and stroke; late mortality rate was five (20%): sudden death in three, pulmonary embolism one and infectious endocardite one. Group B-hospital mortality rate was five (17.2%) patients: low cardiac output three, multiple organs failure one and stroke with pneumonia one; late mortality rate was five (17.2%), distal redissection in three, sudden death in two. The average survival time was 86 +/- 12 for group A and 75 +/- 13 months for group B.

CONCLUSION

The surgery of the aneurysm and dissections of the ascending aorta has shown immediate favorable results and a thorough follow-up to get better late results is needed.

Aspects of the cell growth of Candida guilliermondii in sugar cane bagasse hydrolysate

In this work the behavior of the growth of Candida guilliermondii FTI 20037 in sugar cane bagasse hemicellulosic hydrolysate on various oxygen transfer rates was investigated. The yeast was able to grow and produced xylitol at different performance levels. At 1.0 vvm (volume of air per volume of medium per minute) the highest growth with 24.4 g/l was observed, but no xylitol was produced. At aeration rate of 0.5 vvm the growth was lower, but therefore slight amounts of xylitol (xylitol yield factor-Yp/s = 0.15 g/g) were observed. The lowest cell concentration (10.7 g/l) and the highest xylitol yield (Yp/s = 0.46 g/g) was observed when aeration was changed from 0.5 vvm to 0.05 vvm after 14 h.

Effect of acetic acid on xylose fermentation to xylitol by Candida guilliermondii

The effect of acetic acid concentration on xylose-fermentation to xylitol by Candida guilliermondii FTI 20037 was evaluated in semisynthetic medium containing different concentrations of the acid. Increasing acetic acid concentration up to 1.0 g/l favored xylitol yield and productivity, with maximum values of 0.82 g/g and 0.57 g/l.h, respectively. The presence of acetic acid reduced cell production at all concentration. Furthermore, acetic acid was assimilated by the yeast together with the sugars and was depleted from the medium at concentrations of less than 3.0 g/l. The ability of this yeast to assimilate acetic acid suggests that these cells act as agents of medium detoxification. This behavior may lead to a viable microbiological process of xylitol production by C. guilliermondii FTI 20037 using xylose-rich lignocellulosic hydrolysates in which acetic acid is commonly present, causing inhibition of fermentative activity.

[Use of tranexamic acid for bleeding control in myocardial revascularization]

PURPOSE

To compare two groups of 80 patients undergoing to myocardial revascularization with the use of antifibrinolytic drug tranexamic acid and its efficacy in reduce bleeding and blood transfusion.

METHODS

Prospective analysis of two groups of 80 patients. Group A-no antifibrinolytic therapy (dec 91-may 92) and group B-fibrinolytic therapy-tranexamic acid-10g EV (jun-dec/92). Quantification of mediastinal drainage over 12h as well as the blood or derivatives received at the same time.

RESULTS

Hospital mortality: group A-3.8%, group B-2.5%. Drainage (12h): group A-602 +/- 547 ml and group B-260 +/- 260 ml (p < 0.001). Blood transfusion (12h): group A-1,782 +/- 1,163 ml and group B-1,105 +/- 839 ml (p < 0.001).

COMPLICATIONS

group A-two cases of intraoperative myocardial infarction, one episode of jaundice; group B-one case of intraoperative MI, one reoperation for bleeding control, one episode of jaundice, one of renal insufficiency, two mediastinitis and one seizure. The mean hospitalization time was ten days in both groups.

CONCLUSION

Tranexamic acid was an effective drug in bleeding control and in reducing blood transfusion in the postoperative of patients submitted to myocardial revascularization.

Modified technique for total cavopulmonary connection

The laterolateral anastomosis between the superior vena cava and the pulmonary artery trunk is presented as a modified technique for total cavopulmonary connection. This procedure was successfully performed on a 9-year-old girl, associated with the exclusion of the right atrium, for the treatment of tricuspid atresia and transposition of the great arteries.

Babesia bovis: infectivity of an attenuated strain of Brazilian origin for the tick vector, Boophilus microplus

In order to verify the infectivity and transovarian transmission of one strain of Babesia bovis of Brazilian origin, attenuated by repeated passages in splenectomized calves to the biological tick vector, Boophilus microplus, an inoculation of that strain was performed in hemoparasite-free calves infested with hemoparasite-free ticks. Subsequently, engorged female ticks were collected to examine hemolymph and progeny for presence of developing stages of Babesia bovis. Using an optical microscope, intrahemocytic merozoites were observed in female hemolymph on the second and fourth days, respectively, after ticks dropped from calves. By histological observation of F1 larvae, after more than 24 h of adherence on calves, sporokinetes and small merozoites were present in the samples of hemolymph. These results confirmed the maintenance of infectivity by the vaccine strain attenuated after 26 passages for tick Boophilus microplus.

[Surgical correction of anomalous venous connection of the left lung without extracorporeal circulation]

Surgical correction of anomalous pulmonary venous connection from the left lung to the innominate vein (through a vertical vein) without cardiopulmonary bypass, was performed in two patients, with excellent evolution. After median sternotomy, the ascending vertical vein was cut obliquely close to the vein, and connected to the left atrial appendage. In the postoperative period, the patients were in NYHA class I and the hemodynamic study showed normal venous drainage from the left lung to the left atrium.

Mitral valvuloplasty with a new prosthetic ring. Analysis of the first 105 cases

From October 1987 to March 1993, 105 patients were studied who have undergone valvuloplasty with an open ring. They ranged from 5 to 79 years (mean 30); 33 (31.4%) were under 16. All patients had mitral insufficiency, alone in 62 (59.0%) and associated with mitral stenosis (double mitral lesion) in 43 (41.0%). In the majority of the cases, the aetiology was rheumatic (78.1%); active in 10 (9.5%) patients. Three patients (2.9%) were in class II, 42 (40.0%) in class III, 57 (54.3%) in class IV and 3 (2.9%) in class V. Ten patients (9.5%) had isolated ring implantation while the remaining underwent associated procedures on the leaflets, chordae and papillary muscles. There were two (1.9%) hospital deaths, and six patients (5.7%) had to be reoperated. On the 30th (mean) postoperative day, 75 (71.4%) patients were reevaluated by catheterization, echo Doppler or both to confirm the effectiveness of the techniques employed. The mitral valve was functioning normally or with mitral regurgitation + in 63 (84.0%) patients, mitral regurgitation + + in 2 (2.7%), mitral regurgitation + + + in 5 (6.7%), mitral stenosis + in 4 (5.3%), and mitral stenosis + + in 1 (1.3%) patient. The results were therefore considered excellent in 63 (84.0%) patients with either normal mitral valve or mitral regurgitation +, good in 6 (8.0%) patients with mitral regurgitation + + and/or mitral stenosis +, and poor in 6 (8.0%) patients with mitral regurgitation + + + and/or mitral stenosis + +. Two deaths (1.9%) occurred within the first 7 months of follow-up. Patients were evaluated clinically 1-67 months postoperatively (mean 27):90 (85.7%) were in class I, 4 (3.8%) in class II, 4 (3.8%) in class III and 1 (1.0%) in class IV.(ABSTRACT TRUNCATED AT 250 WORDS)

[A new reconstructive technique in cases of mitral insufficiency caused by the elongation of the chordae tendineae of the anterior cusp. A case report]

A new technique is proposed for mitral incompetence due to elongated chordae tendineae of the anterior leaflet. It consists in shortening the chordae tendineae of the leaflet level. First, we make a longitudinal orifice in the anterior leaflet just near its free edge and the elongated chordae tendineae. Through the orifice and with the help of a micro nerve hook we pull the elongated chordae the necessary to keep the anterior leaflet in the same level of the posterior leaflet. The orifice is then closed with a polipropilene 5-0 suture. The mitral annuloplasty was performed with a Gregori IMC prosthetic ring. The excellent clinical and laboratorial data suggest that mitral insufficiency due to elongated chordae tendineae can be corrected by this technique.

[Prevalence of mouth mucosa changes in 7- to 12-year old students]

The present study had the purpose to evaluate the clinical diagnosis of the oral lesions observed on children. The author examined 1396 children and observed 1670 different alterations. The result were analysed and it is discussed the most prevalent lesions. It is also emphasized the role of the Dentists in performing a more detailed examination in order to reach a better diagnosis and indicate the corresponding preventive nd therapeutic measures.