Morphoagronomic characterization and genetic diversity of a common bean RIL mapping population derived from the cross Rudá x AND 277.

Recombinant inbred lines (RILs) are a valuable resource for building genetic linkage maps. The presence of genetic variability in the RILs is essential for detecting associations between molecular markers and loci controlling agronomic traits of interest. The main goal of this study was to quantify the genetic diversity of a common bean RIL population derived from a cross between Rudá (Mesoamerican gene pool) and AND 277 (Andean gene pool). This population was developed by the single seed descent method from 500 F2 plants until the F10 generation. Seven quantitative traits were evaluated in the field in 393 RILs, the parental lines, and five control cultivars. The plants were grown using a randomized block design with additional controls and three replicates. Significant differences were observed among the RILs for all evaluated traits (P < 0.01). A comparison of the RILs and parental lines showed significant differences (P < 0.01) for the number of days to flowering (DFL) and to harvest (DH), productivity (PROD) and mass of 100 beans (M100); however, there were no significant differences for plant architecture, degree of seed flatness, or seed shape. These results indicate the occurrence of additive x additive epistatic interactions for DFL, DH, PROD, and M100. The 393 RILs were shown to fall into 10 clusters using Tocher's method. This RIL population clearly contained genetic variability for the evaluated traits, and this variability will be crucial for future studies involving genetic mapping and quantitative trait locus identification and analysis.

Effect of generations and environments in the analysis of a partial diallel to improve bean earliness.

The objective of this study was to select genitors based on F1 and F2 generations, evaluated in different environments, to obtain segregating populations for the identification of strains showing improved earliness, yield, and carioca-type grains. Nine bean strains were crossed in a partial diallel scheme (4 x 5), in which group 1 included 4 strains with early cycles and group 2 included 5 elite strains. The F1 and F2 generations and the genitors were assessed in Coimbra and Viçosa in randomized blocks with 3 replications. The following characteristics were evaluated: days between sowing and emergence, and grain yield. We observed an interaction between the effects of general combining ability and specific combining ability with the environments (crop, location, and generation) for both grain earliness and yield. Genetic analysis of earliness revealed a predominance of additive effects and grain yield dominance effects. The strain Goiano Precoce may be used as a genitor in breeding programs to improve earliness, while strains RP1 and VC33 can be used to increase grain yield. We observed genetic complementation between strains Goiano Precoce and RP1, BRSMG Madrepérola and BRS Estilo for earliness and between RP1 and Rosinha Precoce for grain yield.

Effects of sodium hypochlorite associated with EDTA and etidronate on apical root transportation.

AIM: To evaluate the influence of sodium hypochlorite associated with EDTA and etidronate on apical root transportation. METHODOLOGY: Forty-five roots of human mandibular molars with curvatures of 15-25° were embedded in acrylic resin to allow standardized angulation of the initial and final radiographs. The pre-instrumentation radiographs of the mesiobuccal canal of each root were taken using a radiograph digital sensor with a size 15 K-file in the canal. The canals were prepared with the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), using one of the following irrigation regimens during the instrumentation (n = 15): G1 - irrigation with 20 mL of saline solution (control); G2 - alternating irrigation with 2.5% hypochlorite solution (NaOCl) (15 mL); and 17% ethylenediaminetetraacetic acid (EDTA) (5 mL). During instrumentation, the canal was filled with NaOCl and then between each exchange of instrument filled with EDTA for 1 min, and G3 - irrigation with 20 mL of 5% NaOCl and 18% etidronate solution (HEBP) mixed in equal parts. The postinstrumentation radiographs were made with a F3 instrument in the canal. The images were magnified and superposed with Adobe Photoshop software (Adobe Systems, Mountain View, CA, USA). Apical transportation was determined with AutoCAD 2012 software (Autodesk Inc., San Rafael, CA, USA) by measuring the distance in millimetres between the tips of the instruments. The results were subjected to the nonparametric statistical Kruskal-Wallis test (α < 0.05). RESULTS: The median transportation and interquartile range values were 0.00 ± 0.05 for G1, 0.08 ± 0.23 for G2 and 0.13 ± 0.14 for G3. Comparison between groups showed that apical transportation in G3 was significantly greater than in G1 (P < 0.05). CONCLUSION: The use of NaOCl associated with etidronate increased apical transportation in the canals of extracted teeth.

Role of cyclooxygenases 1 and 2 in the maintenance of colonic mucosal integrity in an experimental colitis model.

The role of cyclooxygenase (COXs) isoforms in maintaining colonic mucosal integrity is not fully understood. This study aimed to evaluate the role of COX-1 and -2 on colonic mucosal integrity in an experimental colitis model. Colitis was induced in Wistar rats by intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (20 mg + 50% ethanol). The control group (sham group) received saline only. After 7, 14, or 28 days, colonic samples were removed, and macroscopic lesion scores, wet weight, myeloperoxidase activity, and transepithelial electrical resistance (TER) were determined. In other rat groups, colonic samples from the sham group and a 7th day post-colitis group were mounted in Üssing chambers with the luminal side exposed to a buffer solution (control), acetylsalicylic acid (ASA), SC-560 (COX-1 inhibitor), or celecoxib (COX-2 inhibitor). TER and epithelial permeability to fluorescein were measured. The 7th day colitis group had higher macroscopic damage scores, wet weight, and myeloperoxidase activity and lower basal TER than the sham, 14th day colitis, and 28th day colitis groups. Inhibition of COX-1 but not COX-2 significantly decreased TER and increased permeability to fluorescein in the 7th day post-colitis group compared to the sham group. Additionally, ASA decreased the colonic mucosal integrity on day seven post-colitis compared to the sham group. A decrease in the colonic mucosa integrity in the experimental colitis model can be aggravated only by the inhibition of COX-1, which demonstrated the importance of this enzyme in the maintenance of colonic mucosal integrity.

Does Addition of 10-MDP Monomer in Self-etch Adhesive Systems Improve the Clinical Performance of Noncarious Cervical Lesion Restorations? A Systematic Review and Meta-analysis.

BACKGROUND: Functional acidic monomers are able to chemically interact with hydroxyapatite, and this bond appears to be very stable. Therefore, this aspect of the 10-MDP molecule made it attractive and added to self-etch adhesives. OBJECTIVES: The objective of this Systematic Review (SR) and Meta-analysis (MA) was to determine whether systems with the 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) functional monomer in their formula showed better clinical performance in restorations placed in noncarious cervical lesions (NCCL) when compared to systems without it. The PROSPERO registration number of the MA is CRD42016050538. DATA AND SOURCES: An e-search was conducted through MEDLINE via PubMed, Cochrane Library, Scopus, Web of Science, OpenGrey, Clinical Trials, Current Controlled Trials, and EU Clinical Trials Register, and a search through the references of included studies was also performed. Randomized Controlled Clinical Trials, in which the effectiveness of self-etch adhesive systems, with or without the 10-MDP functional monomer for NCCL, was discussed, were included. Risk of bias was performed according to the Cochrane Collaboration tool, and the certainty of evidence was evaluated through GRADE. STUDY SELECTION: The data were grouped, heterogeneity (I2) was tested, and after duplicate removal, 4208 manuscripts were retrieved. From these, 11 studies were included in the qualitative analysis (risk of bias), with nine classified as low risk and two unclear. GRADE analysis detected moderate-to-high certainty of evidence, so the quantitative synthesis [Meta-analysis (MA)] was performed including the 11 studies. RESULTS AND CONCLUSION: There were no statistical differences in the clinical performance of restorations conducted using "with or without 10-MDP" adhesive types, for all evaluated criteria (p=0.05), with heterogeneity ranging from 0% to 53%. Thus, the presence of 10-MDP functional monomer did not influence the clinical performance of restorations placed in NCCL.

Tumor bearing decreases systemic acute inflammation in rats--role of mast cell degranulation.

OBJECTIVE AND DESIGN: To investigate the effect of experimental tumor bearing on acute inflammation models in rats. METHODS: Four and 7 days after Walker tumor implantation in the right armpit, carrageenan or dextran- induced edema in the contralateral paw, carrageenan induced neutrophil migration into peritoneal cavities, cutaneous vascular permeability induced by bradykinin, histamine, serotonin, substance P, capsaicin or compound 48/80, and mesenteric mast cell degranulation induced by compound 48/80 were evaluated. The control group did not receive tumor implantation. Statistical analysis was performed using one way analysis of variance (ANOVA) followed by the Bonferroni test. RESULTS: On the 7(th) day after tumor inoculation, there were significant decreases in both carrageenan and dextran- induced paw edema. Tumor bearing did not change the neutrophil infiltration induced by carrageenan. There were decreases in cutaneous vascular permeability induced by compound 48/80, serotonin or bradykinin, but not that induced by histamine, substance P. A significant inhibition of mesenteric mast cell degranulation induced by compound 48/80 was observed, on the 4(th) and 7(th) days after tumor inoculation. CONCLUSION: Tumor bearing can limit mast cell function and vascular events in acute systemic inflammation in rats, without changes in neutrophil migration.

A novel two-dimensional dynamic anal ultrasonography technique to assess anismus comparing with three-dimensional echodefecography.

OBJECTIVE: The aim of this prospective study was to test two-dimensional dynamic anorectal ultrasonography (2D-DAUS) in the assessment of anismus and compare it with echodefecography (ECD). METHOD: Fifty consecutive female patients with outlet delay were submitted to 2D and 3D-DAUS, measuring the relaxing or contracting puborectalis muscle angle during straining. The patients were assigned to one of two groups based on ECD findings. Group I consisted of 29 patients without anismus and group II included 21 patients diagnosed with anismus. Subsequently 2D-DAUS images were checked for anismus and compared with ECD findings. RESULTS: Upon straining, the angle produced by the movement of the puborectalis muscle decreased in 26 out of the 29 (89.6%) patients of group I and increased 19 out of the 21 (90.4%) patients of group II. The mean angle during straining differed significantly between group I and group II. The index of agreement between the two scanning modes was 89.6% (26/29) for group I (Kappa: 0.796; CI: 95%; range: 0.51-1.0) and 90.4% (19/21) for group II (Kappa: 0.796; CI: 95%; range: 0.51-1.0). CONCLUSION: Two-dimensional dynamic anal ultrasonography can be used as an alternative method to assess patients with anismus, although the 3-D modality is more precise to evaluate the PR angle as the sphincters integrity as the whole muscle length is clearly visualized.

Evaluation of gastrointestinal motility in awake rats: a learning exercise for undergraduate biomedical students.

Current medical curricula devote scarce time for practical activities on digestive physiology, despite frequent misconceptions about dyspepsia and dysmotility phenomena. Thus, we designed a hands-on activity followed by a small-group discussion on gut motility. Male awake rats were randomly submitted to insulin, control, or hypertonic protocols. Insulin and control rats were gavage fed with 5% glucose solution, whereas hypertonic-fed rats were gavage fed with 50% glucose solution. Insulin treatment was performed 30 min before a meal. All meals (1.5 ml) contained an equal mass of phenol red dye. After 10, 15, or 20 min of meal gavage, rats were euthanized. Each subset consisted of six to eight rats. Dye recovery in the stomach and proximal, middle, and distal small intestine was measured by spectrophotometry, a safe and reliable method that can be performed by minimally trained students. In a separate group of rats, we used the same protocols except that the test meal contained (99m)Tc as a marker. Compared with control, the hypertonic meal delayed gastric emptying and gastrointestinal transit, whereas insulinic hypoglycemia accelerated them. The session helped engage our undergraduate students in observing and analyzing gut motor behavior. In conclusion, the fractional dye retention test can be used as a teaching tool to strengthen the understanding of basic physiopathological features of gastrointestinal motility.

Role of the NO/cGMP/K(ATP) pathway in the protective effects of sildenafil against ethanol-induced gastric damage in rats.

BACKGROUND AND PURPOSE: Sildenafil is a selective inhibitor of cGMP-specific phosphodiesterase. Sildenafil, acting via NO-dependent mechanisms, prevents indomethacin-induced gastropathy. Activation of ATP-sensitive potassium channels (K(ATP)) is involved in gastric defence. Our objective was to evaluate the role of the NO/cGMP/K(ATP) pathway in the protective effects of sildenafil against ethanol-induced gastric damage. EXPERIMENTAL APPROACH: Rats were treated with L-NAME (1 or 3 mg kg(-1), i.p.) or with L-arginine (200 mg kg(-1), i.p.) + L-NAME (3 mg kg(-1), i.p.), the guanylate cyclase inhibitor, ODQ (10 mg kg(-1), i.p.), glibenclamide (0.1, 0.3, 1 or 3 mg kg(-1), i.p.) or with glibenclamide (1 mg kg(-1), i.p.) + diazoxide (3 mg kg(-1), i.p.). After thirty minutes, the rats received sildenafil (1 mg kg(-1), by gavage), followed by intragastric instillation of absolute ethanol (4 ml kg(-1)) to induce gastric damage. One hour later, gastric damage (haemorrhagic or ulcerative lesions) was measured with a planimetry programme. Samples of stomach were also taken for histopathological assessment and for assays of tissue glutathione and haemoglobin. KEY RESULTS: Sildenafil significantly reduced ethanol-induced gastric damage in rats. L-NAME alone, without L-arginine, significantly reversed the protection afforded by sildenafil. Inhibition of guanylate cyclase by ODQ completely abolished the gastric protective effect of sildenafil against ethanol-induced gastric damage. Glibenclamide alone reversed sildenafil's gastric protective effect. However, glibenclamide plus diazoxide did not alter the effects of sildenafil. CONCLUSIONS: Sildenafil had a protective effect against ethanol-induced gastric damage through the activation of the NO/cGMP/K(ATP) pathway.

Peripheral neuropathy and neurological disorders in an unselected Brazilian population-based cohort of IBD patients.

BACKGROUND: Several neurological disorders have been described in inflammatory bowel disease (IBD) patients, but their exact frequency is unknown. METHODS: We prospectively studied the prevalence of neurological disorders (especially peripheral neuropathy) in a group of 82 patients with Crohn's disease (CD, n = 31) or ulcerative colitis (UC, n = 51) from 2 Brazilian tertiary care university clinics and followed them through a period of at least 1 year. All patients were interviewed and had complete neurological evaluations. RESULTS: Large-fiber sensory or sensorimotor polyneuropathy (PN) was observed in 16.1% of the CD and 19.6% of the UC patients. PN was usually mild, predominantly symmetric, and distal with axonal involvement. One patient had demyelinating PN at the diagnosis of CD. Mild carpal tunnel syndrome was common in female UC patients. Sensory symptoms without electromyography abnormalities, suggestive of small-fiber neuropathy or subclinical myelopathy, affected 29% and 11.8%, respectively. After excluding other known etiological or contributory factors for PN, 13.4% of the IBD patients had otherwise unexplained large-fiber or small-fiber PN (7.3% with large-fiber SM PN). Nondebilitating headache was the most common neurological complaint. Three patients had ischemic strokes, 5 were epileptic, and 1 transient chorea. CONCLUSIONS: Neurological disorders, especially PN, are common in our Brazilian cohort of IBD patients. They are diverse, multifactorial, and more common in women. Despite the mild phenotype in most cases, attention should be given by the general practitioner and gastroenterologist since they are frequently undiagnosed. Further studies are necessary to confirm these findings in populations with different genetic and nutritional backgrounds.

Efficacy of glutamine-supplemented parenteral nutrition on short-term survival following allo-SCT: a randomized study.

Fifty-three patients with hematological malignancies who underwent Allo-SCT from HLA-identical siblings were randomly assigned to receive glutamine-enriched parenteral nutrition-PN (GlPN, n=27) or standard PN (PN, n=26), in isonitrogenous solutions. Deaths (D+100 and D+180), infections, acute GVHD, length of stay, time of neutropenia and intestinal permeability (IP) were studied. Ages, gender, diagnosis, disease status and treatment variables were equally distributed between groups. Survival on D+180 was increased in GlPN (74%) vs PN (46%), P=0.03 (log-rank), as on D+100 (P=0.05). Most deaths occurred before D+100, especially in PN (10/26, 39%) vs GlPN (4/27, 15%). GVHD was the most frequent cause of death (8/21, 38%), especially in PN (n=6, five before D+100). Other outcomes were not affected. IP was affected on admission, was not affected by glutamine enrichment, but consistently worsened throughout the study. Results showed that GlPN was efficacious in increasing short-term survival after Allo-SCT. Benefits of glutamine seem to be independent of mucosal protection, as IP was not affected by its use. A trend to a lower incidence of GVHD deaths may suggest an immunomodulatory role of glutamine.

Effect of depth of high-rate ponds on the assimilation of CO2 by microalgae cultivated in domestic sewage.

This study evaluated the effect of high-rate ponds (HRPs) of different depths (20, 30 and 40 cm) on the carbon assimilation by microalgae cultivated in domestic sewage. The efficiency of the dissolution provided by the carbonation column and the carbon release to the atmosphere through the movement of the paddle wheels were also investigated. Dissolution efficiencies of 50%, 48% and 46% were obtained in the HRPs of 20, 30 and 40 cm depth, respectively. These differences can be attributed to the time necessary to recirculate the volume of each HRP in the carbonation column. The volumetric mass transfer coefficients regarding the release to the atmosphere were 0.0007, 0.0005 and 0.0004 min-1 for the 20, 30 and 40 cm HRPs, respectively. The carbon assimilation by the biomass was inversely proportional to depth, with values of 90%, 72% and 68% for the 20, 30 and 40 cm HRPs, respectively. Chlorophyll-a concentration was also higher in the 20 cm HRP. The radiation attenuation at the beginning of the operation was similar among the treatments, resulting in a greater fraction of the pond depth with available radiation in the 20 cm HRP.

Role of cyclooxygenases 1 and 2 in the maintenance of colonic mucosal integrity in an experimental colitis model

The role of cyclooxygenase (COXs) isoforms in maintaining colonic mucosal integrity is not fully understood. This study aimed to evaluate the role of COX-1 and -2 on colonic mucosal integrity in an experimental colitis model. Colitis was induced in Wistar rats by intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (20 mg + 50% ethanol). The control group (sham group) received saline only. After 7, 14, or 28 days, colonic samples were removed, and macroscopic lesion scores, wet weight, myeloperoxidase activity, and transepithelial electrical resistance (TER) were determined. In other rat groups, colonic samples from the sham group and a 7th day post-colitis group were mounted in Üssing chambers with the luminal side exposed to a buffer solution (control), acetylsalicylic acid (ASA), SC-560 (COX-1 inhibitor), or celecoxib (COX-2 inhibitor). TER and epithelial permeability to fluorescein were measured. The 7th day colitis group had higher macroscopic damage scores, wet weight, and myeloperoxidase activity and lower basal TER than the sham, 14th day colitis, and 28th day colitis groups. Inhibition of COX-1 but not COX-2 significantly decreased TER and increased permeability to fluorescein in the 7th day post-colitis group compared to the sham group. Additionally, ASA decreased the colonic mucosal integrity on day seven post-colitis compared to the sham group. A decrease in the colonic mucosa integrity in the experimental colitis model can be aggravated only by the inhibition of COX-1, which demonstrated the importance of this enzyme in the maintenance of colonic mucosal integrity.

Role of TRPV1 receptor in inflammation and impairment of esophageal mucosal integrity in a murine model of nonerosive reflux disease.

BACKGROUND: Microscopic inflammation and impairment of the esophageal epithelial barrier are considered relevant for perception of symptoms in patients with nonerosive reflux disease (NERD). In these patients, the receptor transient receptor potential vanilloid 1 (TRPV1) is overexpressed in the esophageal mucosa, but its role is not yet fully understood. We evaluated the role of TRPV1 in esophageal inflammation and mucosal barrier impairment in a murine model of NERD. METHODS: Nonerosive reflux disease was surgically induced in Swiss mice by pyloric substenosis and ligature of the gastric fundus, and the mice were killed 7 days post surgery. The experimental groups were: I, sham surgery (negative control); II, NERD untreated; III and IV, NERD + SB366791 or capsazepine (TRPV1 antagonists); and V, NERD + resiniferatoxin (for long-term desensitization of TRPV1). The esophagus was collected for western blotting and histopathology and for evaluation of wet weight, myeloperoxidase (MPO), keratinocyte-derived chemokine (KC), transepithelial electrical resistance (TEER), and basal permeability to fluorescein. KEY RESULTS: Compared to sham, NERD mice had increased esophageal wet weight and MPO and KC levels. The mucosa had no ulcers but exhibited inflammation. NERD mice showed mucosal TRPV1 overexpression, a more pronounced decrease in TEER at pH 0.5 (containing pepsin and taurodeoxycholic acid), and increased basal permeability. Pharmacological modulation of TRPV1 prevented esophageal inflammation development, TEER changes by acidic exposure, and increase in esophageal permeability. CONCLUSIONS & INFERENCES: The TRPV1 receptor has a critical role in esophageal inflammation and mucosal barrier impairment in NERD mice, suggesting that TRPV1 might be a pharmacological target in patients with NERD.

Amifostine and glutathione prevent ifosfamide- and acrolein-induced hemorrhagic cystitis.

INTRODUCTION: Ifosfamide (IFS) is an antineoplastic alkylating agent whose major side effect is hemorrhagic cystitis (HC). This toxicity is attributed to the renal excretion of acrolein (ACR), a highly urotoxic IFS metabolite. Despite the clinical use of mesna to prevent HC, a significant percent ( approximately 33%) of patients present with at last one feature of HC, mainly hematuria. AIM: To investigate the use of two antioxidants-amifostine and glutathione-for the prevention of experimental IFS- and ACR-induced HC. MATERIALS AND METHODS: Male Swiss mice were treated intraperitoneal (i.p.) with saline (control), glutathione (125, 250 or 500 mg/kg) or amifostine (25, 50 or 100 mg/kg), and 30 min later they received a single i.p. injection of IFS at a dose of 400 mg/kg. To investigate the systemic effects of the antioxidants on ACR-induced HC, the animals were treated with saline, amifostine (50 mg/kg, i.p.) or glutathione (500 mg/kg, i.p.), and 30 min afterward with 75 mug ACR intravesically (i.ve.). In another set of experiments, the antioxidants were injected directly into the bladder, where the mice received a single i.ve injection of ACR (75 mug) plus amifostine (1.5 mg/kg) or glutathione (2 mg/kg). HC was measured 3 h after IFS or ACR injection according to bladder wet weight, macroscopic (edema and hemorrhage) and microscopic changes, i.e., edema, hemorrhage, cellular infiltration, fibrin deposition and urothelial desquamation. RESULTS: Pretreatments with amifostine or glutathione prevented IFS-induced HC in a dose-dependent manner. Furthermore, ACR-induced HC was also prevented by systemic (i.p.) or local (i.ve.) pretreatment with glutathione or amifostine. The greatest protective effect was seen with local amifostine treatment (2 mg/kg i.ve.) (P < 0.05). CONCLUSIONS: Glutathione and amifostine show a beneficial effect in experimental IFS- and ACR-induced HC. Thus, they should be investigated as an alternative treatment to prevent HC observed in patients undergoing IFS treatment.

Cyclooxygenase-2 inhibition increases gastric tone and delays gastric emptying in rats.

We evaluated the effects of cyclooxygenase-2 (COX-2) selective inhibitors, COX-1 selective inhibitor, or COX non-selective inhibitor on gastric emptying and intestinal transit of liquids, and evaluated the effect of a COX-2 selective inhibitor on gastric tonus (GT). Male Wistar rats were treated per os with saline (control), rofecoxib, celecoxib, ketorolac, rofecoxib + ketorolac, celecoxib + ketorolac, or indomethacin. After 1 h, rats were gavage-fed (1.5 mL) with the test meal (5% glucose solution with 0.05 g mL(-1) phenol red) and killed 10, 20 or 30 min later. Gastric, proximal, medial or distal small intestine dye recovery (GDR and IDR, respectively) were measured by spectrophotometry. The animals of the other group were treated with i.v. valdecoxib or saline, and GT was continuously observed for 120 min using a pletismomether system. Compared with the control group, treatment with COX-2 inhibitors, alone or with ketocolac, as well as with indomethacin increased GDR (P < 0.05) at 10-, 20- or 30-min postprandial intervals. Ketorolac alone did not change the GDR, but increased the proximal IDR (P < 0.05) at 10 min, and decreased medial IDR (P < 0.05) at 10 and 20 min. Valdecoxib increased (P < 0.01) GT 60, 80 and 100 min after administration. In conclusion, COX-2 inhibition delayed the gastric emptying of liquids and increased GT in rats.

Twenty years of post-fire plant succession in a "cerrado", São Carlos, SP, Brazil.

Secondary succession in degraded areas is little studied, especially where long-term observation of evolutionary processes is concerned. The aim of this work was to follow the qualitative and quantitative changes in vegetation throughout the regeneration process after fire in a cerrado with forest physionomy. The area under study is a reserve on CPPSE-EMBRAPA's farm, São Carlos region of São Paulo State, Brazil. In 1981, an especially destructive fire eliminated the aerial part of the vegetation and litter. From that time, the vegetation in three permanent quadrats of 2 x 20 m was recorded for twenty years. The results demonstrated the rapid growth of herbs, shrubs, climbers and trees successively, with a great species richness and, after a certain time, a decline in density at a rate similar to the initial recovery. Both the soil seed bank and sprouting subterranean organs played important parts in the recovery of the vegetation. Three phases were observed in the plant succession: plant growth, followed by intraspecific competition with a reduction in the number of individuals and finally interspecific competition with the disappearance of some species from the quadrats. The different populations behaved similarly and the rise and fall in density of each species over time reflected their ecological role.

Late marrow allograft rejection following alpha-interferon therapy for hepatitis in a patient with paroxysmal nocturnal hemoglobinuria.

We describe a case of allograft rejection that occurred 23 months after successful bone marrow transplantation for severe aplastic anemia in a patient with paroxysmal nocturnal hemoglobinuria. The allograft rejection appears to have been induced by recombinant alpha-interferon (rINF-alpha) treatment for non-A, non-B hepatitis that developed 11 months after transplantation. During the 9 months of active hepatitis, the donor graft functioned normally; however, 3 months after rINF-alpha therapy was started, pancytopenia and a chimeric hematopoietic state developed. rINF-alpha was discontinued, cyclosporin A was reintroduced, and autologous bone marrow recovery followed. rINF-alpha treatment may be detrimental to some recipients of allogeneic bone marrow transplants.

Translocation of CD3D gene in an acute myeloid leukemia (M5) with t(11;17)(q23;21).

Cytogenetic studies in patients with acute leukemia showed structural abnormalities on chromosome 11 at band q23 in five cases. Four of these had acute lymphoblastic leukemia (ALL) associated with t(4;11)(q21;q23) and one case had acute nonlymphoblastic leukemia (ANLL) (M5) associated with t(11;17)(q23;q21). We examined the CD3D and c-ets-1 genes in the t(11;17)(q23;q21) patient to ascertain any association between them and the chromosome change. In situ hybridization results showed that unlike in other studied cases with rearrangements of 11q23, the CD3D gene in the t(11;17)(q23;21) is transposed to the der(17) chromosome, providing evidence for a different breakpoint in the 11q23 region.

Role of tumor necrosis factor and nitric oxide in the cytotoxic effects of Clostridium difficile toxin A and toxin B on macrophages.

Clostridium difficile, the bacterium involved in antibiotic-associated colitis, produces two exotoxins, toxin A (TxA) and toxin B (TxB). Although these toxins are well recognized as being cytotoxic to several mammalian cell types, the mechanisms involved are not fully understood. The aim of the present investigation was to examine the cytotoxicity of TxA and TxB to peritoneal macrophages in culture and to investigate whether tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) are involved in the process. As a control, the effect of E. coli LPS was also investigated. TxA, TxB and LPS were dose-dependently cytotoxic to macrophage monolayers, with TxB being the most potent. All of the toxins stimulated the release of TNF-alpha from macrophages. TxB was again the most active in inducing this response. The TNF-alpha released appears to be involved in the action of LPS and TxA, but not of TxB, since a mAb against TNF-alpha inhibited the cytotoxicity of the former two but had no effect on the latter. NO is not involved in the effects of TxA and TxB since these toxins did not induce the production of this mediator in macrophages, even in the presence of IFN-gamma. In addition, L-imino-ethyl-L-ornithine (L-NIO), a NO synthase inhibitor, did not modify the macrophage death caused by TxA or TxB. Although LPS was able to induce the production of high amounts of NO, NO did not mediate the LPS cytotoxicity since L-NIO did not influence the degree of macrophage death caused by LPS. TxA and TxB therefore appear to exert cytotoxic effects on cultured macrophages by different mechanisms. TNF-alpha is involved in TxA and LPS-mediated cytotoxicity but not in the toxicity caused by TxB. NO is not involved in the killing action of any of these toxins.