Production of beta-glucan and related glucan-hydrolases by Botryosphaeria rhodina.

AIMS: Characterization of beta-glucan production from Botryosphaeria rhodina DABAC-P82 by detecting simultaneously glucan-hydrolytic enzymes and their localization, culture medium rheology and oxygen transfer. METHODS AND RESULTS: Mycelium growth, beta-glucan production, substrate consumption and glucan-hydrolytic enzymes were monitored both in shaken flasks and in a 3-l stirred-tank bioreactor. Glucan production (19.7 and 15.2 g l(-1), in flask and bioreactor, respectively) was accompanied by extra-cellular and cell-bound beta-glucanase and beta-glucosidase activities. In the bioreactor scale, in the time interval of 0-78 h the apparent viscosity of the culture broth exhibited a general increase; thereafter, it began to reduce, probably because of the above glucan-hydrolytic activities. Moreover, the culture media collected after 45 h behaved as solid-like materials at shear rates smaller than 0.001 s(-1), as pseudo-plastic liquids in the middle shear rate range and as Newtonian ones at shear rates greater than 1000 s(-1). CONCLUSION: The greatest beta-glucan accumulation in the bioreactor was found to be associated with nitrogen and dissolved oxygen concentrations smaller than 0.15 g l(-1) and 25%, respectively, and with the peak points of the glucan-degrading enzymes. SIGNIFICANCE AND IMPACT OF THE STUDY: A careful analysis of the critical factors (such as, culture broth rheology, oxygen mass transfer and glucan-hydrolytic enzymes) limiting the beta-glucan production by B. rhodina is a prerequisite to maximize beta-glucan yield and production, as well as to define the process flow sheet capable of maximizing biopolymer recovery, solvent re-utilization and glucose consumption.

Study and application of a mathematical model for the provisional assessment of areas and nasal resistance, obtained using acoustic rhinometry and active anterior rhinomanometry.

Nasal resistance (NR) depends on the geometrical features and tortuosity of the nasal airway and on the air flow. Knowing the longitudinal distribution of cross-sectional areas (CSAs) in the nasal cavity (which can be obtained using acoustic rhinometry) and the laminar nasal resistance (obtainable by processing the rhinomanometric results), it is possible to calculate, utilizing a mathematical model elaborated on the basis of fluid dynamics, the differential nasal resistance (NRdiff) and the cumulative nasal resistance (NRcum), thus localizing the position at which the highest resistance is concentrated and the related longitudinal distribution. Using a mathematical model, we integrated the sigmoid curves DeltaP/Q of rhinomanometry with the cross-sectional areas obtained using acoustic rhinometry, thus obtaining the normal distribution of differential and cumulative nasal resistances. Afterwards, we empirically reduced the cross-sectional areas corresponding to the head, body, tail and the whole inferior turbinate, recalculating the differential and cumulative nasal resistance distribution curves. The results show that reduction of up to 50% of cross-sectional areas does not substantially affect the resistivity role of the nasal valve, while greater reductions move the highest resistivity point to an area at the junction of the body and the head of the inferior turbinate. The study of the differential nasal resistance trend curves as a function of the reduction of cross-sectional areas shows that the resistance variation of the body and the whole inferior turbinate prevail with reductions of up to 40%, while the variation of cross-sectional areas of the body bordering the inferior turbinate head is predominant with higher reductions. The cross-sectional areas of the nasal airway cavity with highest resistivity are mainly located in an anterior position, where the differential nasal resistances are higher, but there are substantial variations produced by reducing the cross-sectional area of the posterior nasal airway. A similar model can produce provisional values for the results obtainable with functional nasal surgery.

Nonendemic pemphigus foliaceus presenting as fatal bullous exfoliative erythroderma.

Pemphigus foliaceus is a cutaneous autoimmune blistering disease that is characterized by lower morbidity and mortality than those observed in pemphigus vulgaris or paraneoplastic pemphigus. However, erythrodermic forms of the endemic variant of pemphigus foliaceus have been associated with a higher mortality. We report a case of nonendemic pemphigus foliaceus that presented as fatal bullous exfoliative erythroderma, and thus, we will emphasize the inclusion of this entity in the differential diagnosis and the use of skin direct immunofluorescence in the evaluation of patients with erythroderma.

Effect of pH and stirring rate on itaconate production by Aspergillus terreus.

The production of itaconic acid from glucose-based media by Aspergillus terreus NRRL 1960 was found to be controlled by stirring rate and pH. When the phosphorous (P) level in the production medium was reduced to less than 10 mg l(-1), the fungal mycelium exhausted its primary growth and started to excrete itaconic acid, while it continued its secondary growth at the expense of ammoniacal nitrogen. The fermentation exhibited a mixed-growth-associated product formation kinetics, the non-growth associated production term (mI) being practically zero only when the pH was left free to change from 3.4 down to 1.85. On the contrary, when the pH was kept reducing up to a constant value by automatic addition of KOH 4 mol l(-1), the itaconate yield coefficient on the initial glucose supplied (Y(I/So)) and mI and were 0.53 g g(-1) and 0.028 h(-1) at pH 2.4 and 320 rev min(-1) and 0.5 g g(-1) and 0.036 h(-1) at pH 2.8 and 400 rev min(-1), respectively. Although the differences between mI and Y(I/So) were statistically insignificant at the 95% confidence level, the net difference in the corresponding yield coefficients for itaconic acid on mycelial biomass resulted in a maximum itaconate production rate of 0.41 g l(-1) h(-1) at pH 2.8 and 400 rev min(-1), thus showing that this operating condition is no doubt optimal for the process under study.

Non-specific nasal provocation test with histamine. Analysis of the dose-response curve.

Non-Specific Nasal Hyper-reactivity (NSNH) is described as a clinical condition characterized by the presence of rhinitic symptoms that are a consequence of non-specific stimulations. Because of its effects on vascular, epithelial, and glandular receptors, NSNP Test (NSNPT) with histamine allows the study of NSNH. The aims of this study are 1. to analyze the behavior of NSNH both in non-allergic chronic vasomotory patients and in healthy control subjects 2. to correlate total nasal resistance(TNR) to each dosage of histamine to derive the dose/response curves and 3. to study these curves to analyze and possibly define different stages according to the intensities of response of NSNH. We have studied 26 subjects affected by non-allergic vasomotor rhinitis and 10 healthy control subjects. We sprayed a NSNPT with histamine-phosphate (0.2-0.3-0.4-0.5-0.6-0.8 mg) in different sessions to avoid accumulation phenomena. Five minutes before and five minutes after each challenge, TNR was determined by active anterior rhinomanometry. TNR was correlated to the doses of histamine by an empirical equation. The most important results of this study are as follows: a) the variation of TNR follows a model of exponential curve, b) it is possible to classify NSNH, as a function of the regression b coefficient belonging to the empirical equation used, in reactivity classes, c) from one reactivity class to another, post-stimulation TNRs double; 0.5 mg of histamine of the NSNPT is the optimal dose, d) there is an overlap between the responses of some normal subjects and rhinopathic patients that will be the subject of a further study. Finally, our data suggest that, in a future perspective, it is possible to use the NSNPT with histamine for diagnostic, prognostic and therapeutic control purposes.

Effect of some operating variables on citrate recovery from model solutions by electrodialysis

The effect of pH and temperature (straight theta) on the overall performance indicators (i.e., solute recovery, rho, and Faraday, eta, efficiencies; specific energy consumption, epsilon, solute, JS, and water, JW, fluxes) of batch electrodialytic recovery of citric acid from model solutions was assessed at different values of feed solute concentration (cSf) and electric current density (j). Regardless of the initial feed concentration used, rho and JS were found to be independent of straight theta; eta and JW exhibited a positive trend with respect to straight theta, while epsilon a negative one. At the maximum temperature tested (33 degrees C), as the pH of the feed solution was varied from 3 to 7, rho increased from 0.90 +/- 0.08 to 0.97 +/- 0.02, eta grew from 0.09 +/- 0.02 to 0.50 +/- 0.01, JS practically doubled, epsilon reduced about 8 times, but JW increased from 3 to 4 times. So, the optimal conditions for this technique are to be determined by balancing the savings in the investment and maintenance costs against the energy costs. Copyright John Wiley & Sons, Inc.

Fumaric acid production from hydrolysates of starch-based substrates.

Fumaric acid production by Rhizopus arrhizus from commercial hydrolysates of corn starch (i.e. glucose molasses) was studied at different initial concentrations of glucose (S) and C:N ratios (R) by performing a 3(2) factorial experiment. By using the response surface methodology and statistical analysis, fumaric acid (YF) and mycelial biomass (YX) yields, as referred to the initial concentration of glucose and fumaric acid productivity (PF), were fitted to the only significant first-order effects of S and R with mean percentage errors ranging from 11 to 15%. The resulting empiric models were used to determine the optimal values of S (100-130 g dm-3) and R (150-210 g-atom C per g-atom N) associated with YF and PF varying in the ranges 40-49% and 7-8.5 g dm-3 day-1, respectively. After establishing the validity of these data at the 95% confidence level, an optimal operating condition (S = 120 g dm-3 and R = 150) was further tested using other substrates (i.e. glucose and acid or enzymatic hydrolysates of cassava, corn and potato flours). Statistically significant improvements in the fumaric acid yield and productivity were determined with respect to the predicted values. Since the highest values of YF and PF were obtained from the acid hydrolysates of the starch-based materials and such values were also found to be insensitive to the substrate used (at a probability level of 0.05), the above operating condition might be further employed to minimise fumaric acid production costs as a function of the feedstock used.

A new approach to sciatic nerve block in the gluteal region.

Two personal techniques of sciatic nerve block in the gluteal region were compared in a retrospective study. The study was carried out on 224 patients undergoing elective orthopaedic lower-limb surgery. The block was performed in 107 subjects with a modified Labat's technique, prolonging his line downwards to meet the surface projection of the sciatic nerve, according to Ellis and McLarry. In 117 patients the needle was inserted at the intersection of the hiatus-trochanteric line with a straight line joining the midpoint of the thigh with the posterior-superior iliac spine. The use of these landmarks improved paraesthesia elicitation and increased absolute success rate (66%). A dramatic drop in intra-operative supplemental analgesic and hypnotic needs was observed in these patients. Failure occurred in about 10% with both techniques, whilst side-effects were of minor importance. These results suggest that the new landmarks provide a more precise anatomo-clinical location of the sciatic nerve.

The ejector-loop fermenter: Description and performance of the apparatus.

A novel fermentation unit, the ejector-loop fermenter (ELF), consisting of an outer-loop tower fermenter, a centrifugal pump, a plate-heat exchanger, and a gas-liquid ejector, was designed and constructed. Aeration was achieved by continuously recirculating the fermentation medium through two different nozzle devices instead of using the traditional expensive air compressor. By carrying out a whey fermentation with Kluyveromyces fragilis as the test organism, either in the ELF or in conventional stirred fermenter, it was possible to confirm that the high sheat streses and mixing shock occurring in the ejector nozzle and diffuser sections did not affect microbial growth. Within the range of experimental power consumption per unit volume (-0.1-5 kW/m(3)), the oxygen transfer capability of the ELF per unit power input was found to vary from 1 to 2.5 kg O(2) kW(-1)h(-1). Moreover, it is shown that there is suficient room for improvement in the performance of the ELF unit by care fully designing the aeration device. In fact, at constant volumetric oxygen transfer coefficient, the power consumpotion per unit volume in a 4-mm nozzle was found to be about 40% less than that in a 6-mm nozzle.