The roles of calcium in sludge granulation during UASB reactor start-up

Six upflow anaerobic sludge blanket (UASB) reactors were concurrently operated for 146 d to examine the effects of calcium on the sludge granulation process during start-up. Introduction of Ca2+ at concentrations from 150 to 300 mg/l enhanced the biomass accumulation and granulation process. The calcium concentration in the granules was nearly proportional to the calcium concentration in the feed, and calcium carbonate was the main calcium precipitate in the granules. The specific activity of granules decreased with increasing influent calcium concentration. The optimum calcium concentration for the granulation was from 150 to 300 mg/l. The addition of low-concentration calcium to the UASB reactors appeared to enhance the three steps of sludge granulation: adsorption, adhesion and multiplication, but it did not lead to a different proliferation of predominant microorganisms in the granules.     

Natural honey prevents ischaemia-reperfusion-induced gastric mucosal lesions and increased vascular permeability in rats

OBJECTIVE: It has been proposed that natural honey may contain a 'sucralfate-like' substance. Recent studies have shown that sucralfate affords protection against ischaemia-reperfusion-induced injuries in the rat stomach. Therefore, the effect of honey was studied on ischaemia-reperfusion-induced gastric lesions, intraluminal bleeding, vascular permeability and non-protein sulphhydryls (NP-SH) in the rat stomach. METHODS: Rats were subjected to 30 min of gastric ischaemia in the presence of 100 mM HCl and reperfusion period of 60 min. Intraluminal bleeding was assessed macroscopically and the gastric lesions were graded microscopically under an inverted microscope. Vascular permeability was quantified by measuring spectrophotometrically the extravasated Evans blue dye in the stomach. NP-SH levels were measured spectrophotometrically. A luminol-dependent chemiluminescence method was used to assess antioxidant effects of honey in vitro. RESULTS: There were significantly more gastric lesions, more severe intraluminal bleeding, more leakage of Evans blue and depletion of NP-SH during the reperfusion period as compared to controls. Pre-treatment with honey (0.078-0.625 g/kg, orally) or dimethyl sulphoxide (0.02-0.08 g/kg, intraperitoneally) 30 min before the ischaemia-reperfusion dose-dependently reduced the gastric lesions and intraluminal bleeding and decreased the vascular permeability. Furthermore, honey reversed the ischaemia-reperfusion-induced depletion of NP-SH levels and inhibited the luminol-dependent chemiluminescence induced in a cell-free xanthine-xanthine oxidase system. CONCLUSION: These results suggest that gastric protection by honey may be a result of its antioxidant effect. It is suggested that this property of honey may be due to the presence of a 'sucralfate-like' substance.     

A compilation of mutations located in the cytochrome b subunit of the bacterial and mitochondrial bc1 complex

We used a SCID mouse xenograft model to study the in vivo growth patterns of primary leukemic cells from six patients with newly diagnosed B-cell precursor (BCP) acute lymphoblastic leukemia (ALL), including two patients with t(1;19) ALL, two patients with t(4;11) ALL, and two patients with t(9;22) ALL. Leukemic cells from these six patients caused overt leukemia in SCID mice with extensive multiple organ involvement. Leukemic BCP from SCID mice xenografted with leukemic cells from two t(9;22) ALL patients expressed very high levels of both VLA-4 and VLA-5 regardless of the tissue of origin. By comparison, in SCID mice xenografted with leukemic cells from the two patients with t(1;19) ALL and two patients with t(4;11) ALL, leukemic BCP from the bone marrow samples expressed high levels of VLA-4 as well as VLA-5, whereas the vast majority of leukemic BCP in the liver or spleen samples expressed neither of these adhesion molecules at significant levels. These results suggest that the expression of VLA-4 and VLA-5 on t(1;19) or t(4;11) leukemia cells likely determines their binding capacity to bone marrow stroma and may affect their migration to extramedullary tissues. Our findings are in accord with and extend previous studies which demonstrated that extracellular matrix and integrins influence development, compartmentalization, and migration of BCP during B-cell ontogeny. The described SCID mouse model system provides a unique opportunity to study the adhesion receptors which regulate the selective homing of human leukemic BCP to specific SCID mouse organs.     

Temporal selectivity of evoked vocal responses of Batrachyla antartandica (Amphibia: Leptodactylidae)

The advertisement call of the leptodactylid frog Batrachyla antartandica from southern Chile consists of a train of brief percussive tone pulses whose energy is centred at about 2 kHz. To gain an understanding of the temporal features that are essential for call recognition, playback experiments were conducted with 11 males. Subjects were presented with a synthetic imitation of this signal and variants for which different temporal call parameters were modified systematically. The number of pulses, pulse rate and latency of evoked vocal responses (EVRs) to stimuli having high pulse repetition rates (i.e. 8 and 16 pulses/s) were significantly weaker relative to responses to stimuli having an equal number of pulses but lower pulse rates. A similar, non-significant tendency was observed for a series of stimuli with different pulse rates for which the total stimulus duration was held constant. EVRs also decreased significantly for stimuli having long pulse durations (i.e. 48 and 96 ms) relative to stimuli comprising shorter pulses. No significant differences were observed between EVRs to stimuli for which pulse rise and fall times were varied from 1-20 ms. Responses to calls comprising trains of 10 pulses were weaker compared with stimuli having fewer pulses per train. The selective EVRs of B. antartandica for different temporal parameters contributes to an understanding of the mechanisms involved in call recognition and stress the relevance of temporal processing of sound by males for the emergence of specific patterns of vocal behaviour in anurans.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour     

Management of metatarsus adductovarus

A retrospective analysis of 795 patients treated for metatarsus adductovarus by a standardized outpatient approach by one of the authors (D.S.W.) from 1970 to 1983 was conducted to evaluate the efficacy of a straight metal bar and attached reverse last shoe protocol. Criteria for inclusion were developed excluding those milder cases in which spontaneous resolution was expected and indeed occurred. Nearly uniform excellent results were encountered, with a 99% likelihood of obtaining a fully corrected foot. Surgical intervention was deemed necessary in under 1% of cases seen. The authors also examined birth weights and rank in relation to metatarsus adductovarus. Those children with the deformity had a mean birth weight of 7.6 pounds, without statistical variance from normal average birth weights. We were unable to establish any statistical association with birth rank. In light of the results of this study, which compare favorably with serial casting, we recommend this approach as a more economical and less disruptive and cumbersome technique for parent, patient, and physician.     

Passive-active immunization in infants of hepatitis Be antigen-positive mothers. Comparison of the efficacy of early and delayed active immunization

OBJECTIVE: To assess the efficacy of late active immunization against hepatitis B concomitant with diphtheria, pertussis, tetanus, and polio vaccine in high-risk infants receiving hepatitis B immune globulin at birth. DESIGN: Randomized study of infants born to mothers positive for hepatitis B surface antigen (HBsAg) and hepatitis Be antigen (HBeAg). SETTING: Three large city hospitals and one rural area providing prenatal care and obstetric services. SUBJECTS: Eighty neonates of HBsAg- and HBeAg-positive carrier mothers received 0.5 mL/kg of body weight hepatitis B immune globulin within 2 hours of birth and hepatitis B vaccine (10 micrograms) at 0, 1, 2, and 11 months of age (group A) or at 3, 4, 5, and 11 months of age concomitant with diphtheria, pertussis, tetanus, and polio immunization (group B). A second dose of hepatitis B immune globulin was given to infants on schedule B at 3 months. MAIN OUTCOME MEASURES: Blood samples were collected at 0, 3, 6, 11, and 12 months of age and tested for antibodies against hepatitis B core antigen and HBsAg. Follow-up visits were scheduled annually up to 5 years of age. RESULTS: Eight infants were excluded from analysis. During the study period, six children became HBsAg carriers, three in each group, which corresponds to a 5-year incidence of infection of 9% and 8% for groups A (three of 35) and B (three of 37), respectively. Subclinical infections (persistent anti-HBc positivity beyond month 12 or appearance of anti-HBc) were encountered in another eight infants (four in each group). CONCLUSION: Late active immunization starting at 3 months of age appears to provide similar protective efficacy as active immunization starting at birth when combined with hepatitis B immune globulin at 0 and 3 months of age.