Enhanced plant tolerance to iron starvation by functional substitution of chloroplast ferredoxin with a bacterial flavodoxin

Iron limitation affects one-third of the cultivable land on Earth and represents a major concern for agriculture. It causes decline of many photosynthetic components, including the Fe-S protein ferredoxin (Fd), involved in essential oxidoreductive pathways of chloroplasts. In cyanobacteria and some algae, Fd down-regulation under Fe deficit is compensated by induction of an isofunctional electron carrier, flavodoxin (Fld), a flavin mononucleotide-containing protein not found in plants. Transgenic tobacco lines expressing a cyanobacterial Fld in chloroplasts were able to grow in Fe-deficient media that severely compromised survival of WT plants. Fld expression did not improve Fe uptake or mobilization, and stressed transformants elicited a normal deficit response, including induction of ferric-chelate reductase and metal transporters. However, the presence of Fld did prevent decrease of several photosynthetic proteins (but not Fd) and partially protected photosynthesis from inactivation. It also preserved the activation state of enzymes depending on the Fd-thioredoxin pathway, which correlated with higher levels of intermediates of carbohydrate metabolism and the Calvin cycle, as well as increased contents of sucrose, glutamate, and other amino acids. These metabolic routes depend, directly or indirectly, on the provision of reduced Fd. The results indicate that Fld could compensate Fd decline during episodes of Fe deficiency by productively interacting with Fd-dependent pathways of the host, providing fresh genetic resources for the design of plants able to survive in Fe-poor lands.     

Bioassay guided purification of the antimicrobial fraction of a Brazilian propolis from Bahia state

Background  

Brazilian propolis type 6 (Atlantic forest, Bahia) is distinct from the other types of propolis especially due to absence of flavonoids and presence of other non-polar, long chain compounds, but presenting good in vitro and in vivo antimicrobial activity. Several authors have suggested that fatty acids found in this propolis might be responsible for its antimicrobial activity; however, so far no evidence concerning this finding has been reported in the literature. The goals of this study were to evaluate the antibacterial activity of the main pure fatty acids in the ethanolic extract and fractions and elucidate the chemical nature of the bioactive compounds isolated from Brazilian propolis type 6.     

Influence of Preoperative Feeding on the Healing of Colonic Anastomoses in Malnourished Rats

Background: Malnutrition influences healing of gastrointestinal anastomoses. The authors hypothesize that colonic anastomotic healing is decreased by malnutrition and might be improved by preoperative feeding. Methods: Eighty adult male Wistar rats were divided into 4 groups: (1) control rats 1 (C1), fed regular chow ad libitum for 21 days; (2) malnourished pair‐fed rats (M), fed 50% of the food ingested by the control rats for 21 days; (3) preoperative nutrition rats (PRE), fed 50% of the average of the controls for 21 days and then fed preoperative nutrition with regular chow ad libitum for 1 week before the operation; and (4) control rats 2 (C2), fed regular chow ad libitum for 28 days. On days 21 (C1 and M) and 28 (PRE and C2), rats underwent 2 colonic transections and, subsequently, 2 end‐to‐end anastomoses. Rats were killed on postoperative day 5. The anastomoses were ressected for tensile strength and histological analysis. Results: PRE rats showed increased maximal tensile strength vs the M group (0.09 ± 0.01 vs 0.15 ± 0.01; P < .05) and similar values of maximal tensile strength as the controls (0.15 ± 0.01 vs 0.15 ± 0.02; P = .91). Collagen type I was higher in controls vs the PRE group (6.13 ± 0.39 vs 4.90 ± 1.53; P < .05); nevertheless, the PRE group showed higher collagen type I than M rats (4.90 ± 0.36 vs 3.83 ± 0.35; P < .05). Conclusions: Preoperative feeding for 7 days increases the maximal tensile strength, as well as the percentage area of mature collagen, approaching similar values as the control group.     

Lack of efficacy of high-dose intravenous immunoglobulin treatment of severe thrombocytopenia in patients with secondary dengue virus infection

Because most cases of secondary dengue virus infection are associated with an increased level of platelet-associated IgG, a high dose of intravenous immunoglobulin (IVIG) may have an effect on the development of severe thrombocytopenia in this disease. A randomized, controlled study was conducted with two treatment groups consisting of a treatment (IVIG) group (n = 15) and a non-treatment (non-IVIG) group (n = 16) to determine whether a high dose of IVIG is effective in hastening the recovery from thrombocytopenia in patients with secondary dengue virus infection. No significant difference was found in the baseline demographic data between the two groups. No adverse effect of IVIG was observed, but no effect in hastening the recovery of platelet counts was found in patients with secondary dengue infections. The lack of efficacy of IVIG suggests that platelet clearance by macrophages through Fc gamma receptors is not a primary mechanism in this disease.     

Comparison of short bowel syndrome acquired early in life and during adolescence

BACKGROUND: Prolonged survival in pediatric patients with short bowel syndrome (SBS) is now possible because of parenteral nutrition and small bowel transplantation. We hypothesized that there may be important differences between adult patients who developed SBS during early childhood and those who develop this as adolescents. METHODS: Sixty-seven patients between the ages of 16 and 40 years were studied. Thirty patients developing SBS younger than 12 years comprised the pediatric group (PG), 37 developing SBS at age 13 to 25 constituted the adolescent group (AG). RESULTS: Midgut volvulus (n=11) was the most common cause in the PG followed by gastroschisis (n=5), intestinal atresia (n=5), and necrotizing enterocolitis (n=4). The most common cause of SBS in the AG was trauma (n=13), followed by tumors (n=7) and postoperative complications (n=5). A similar portion in each group had intestinal remnants less than 60 cm (69% vs. 58%), however, the PG was more likely to have a colon remnant (97% vs. 71%, P<0.05), and less likely to have an ostomy (7% vs. 47%, P<0.05). Patients in PG were followed significantly longer than AG (246+/-67 vs. 90+/-58 months, P<0.05). A similar portion of the patients require long-term parenteral nutrition (86% vs. 84%) or have undergone intestinal transplant (28% vs. 23%). Significantly more pediatric patients had negative height z scores when compared with the adolescents. CONCLUSIONS: Acknowledging the inherent biases created in defining the two groups, pediatric patients developing SBS early in life seem to be similar to those who develop SBS as adolescents with regards to long-term outcome, despite differences in origin and intestinal anatomy.     

Empyema and lung abscess as complication of a perforated appendicitis in a pregnant woman

INTRODUCTIONThe development of empyema as a result of an intra-abdominal pathology is a rare condition.PRESENTATION OF CASEWe present a 31-year-old woman at 28 weeks’ gestation who was referred to our hospital with diagnosis of pneumonia with pleural effusion. She presented with signs of septicemia and fetal distress. A thoracic-abdominal-pelvic CT-scan showed a right pleural effusion with a retroperitoneal collection in contact with the pleural space. Due to her critical condition, immediate surgical exploration and pregnancy interruption was decided. The fetus was delivered by cesarean with satisfactory vitality. After abdominal exploration, a retrocecal appendicular abscess was evidenced and appendectomy was performed. Subsequently, the right chest was accessed through a posterolateral thoracotomy. An empyema with lung abscess and purulent fluid accessing from the retroperitoneum at the posterior pleural space was found. Due to parenchymal compromise, a right inferior lobectomy was performed. The patient had an uneventful recovery and was discharged at postoperative day 10.DISCUSSIONA septic condition in a pregnant patient with significant thoraco-abdominal infection requires an aggressive approach, with interruption of pregnancy and urgent exploration of the chest and abdomen.CONCLUSIONWhen an empyema is developed in absence of lung disease or other intrathoracic cause, intra-abdominal origin should be considered.     

Phase I and pharmacokinetic study of 502U83 (an arylmethylaminopropanediol) in cancer patients.

502U83, a novel arylmethylaminopropanediol, has proven active in vivo against a panel of murine leukemia and solid tumors as well as in a tumor clonogenic assay against a variety of fresh human cancers. A total of 35 previously treated cancer patients were enrolled in a phase I study of this compound. The maximally tolerated dose (MTD) appears to be 12,800 mg/m2/72 h by continuous intravenous infusion with severe granulocytopenia occurring in three of five patients. There were no objective clinical responses. Serum pharmacokinetic parameters were as follows: plasma terminal phase half-life (t1/2 beta) = 3.84 h; total body clearance (CLB) = 53.1 l/h/m2; volume of distribution at steady state (Vdss) = 127.9 l/m2; maximum plasma concentration (Cmax) = 3.7 micrograms/ml (at 12,800 mg/m2/72 h dose).