Changes of glial-neuronal interaction and metabolism after a subconvulsive dose of pentylenetetrazole

Pentylenetetrazole (PTZ) injection causes seizures in rodents and this is used in several models of epilepsy. In the present study a low dose (20 mg/kg) was injected into rats in order to analyze metabolic disturbances caused by subconvulsive amounts of PTZ. Intraperitoneal injection of PTZ was followed, 30 min later, by injection of [1-(13C)]glucose plus [1,2-(13C)]acetate and 15 min thereafter decapitation. Analyses of extracts from cerebrum, subcortex and cerebellum were performed using 13C NMRS and HPLC. Whereas convulsive doses of PTZ lead to most pronounced changes in cerebellum [J. Neurochem. 85 (2003) 1200], it could be shown that subconvulsive doses affected mainly amino acid metabolism in cerebrum. In glutamatergic neurons in the cerebrum PTZ affected both the metabolic and releasable pools of glutamate, whereas, in the subcortex and cerebellum only the metabolic pool was affected. This could be deducted from the findings that less [4-(13C)]glutamine, [3,4-(13C)]glutamate and [2-(13C)]aspartate, which are labeled from [1-(13C)]glucose, were detected in this area. Glial metabolism was also changed as evidenced by the decreased pyruvate carboxylation versus pyruvate dehydrogenation ratio both in cerebrum and subcortex. Comparison between convulsive and nonconvulsive doses of PTZ lead to the hypothesis that changes observed in the cerebellum are mainly due to seizures, whereas those in cerebrum and subcortex are coupled to the action of the chemical stimulant.     

Effects of Ballota nigra on blood biochemical parameters and insulin in albino rats

Ingestion of aqueous 70% ethanol extract of Ballota nigra (400 mg/kg body weight for 7 days) by albino rats (n=10) was investigated to study its effects on glucose, total cholesterol, triglycerides, aspartate aminotransferase (AST), alanine aminotransferase (ALT), troponin I (TnI), serum creatine kinase (CK), total protein, total bilirubin and blood urea. Ballota nigra extract caused a significant decrease in blood glucose, total serum cholesterol and CK levels. Blood levels of TnI, AST, ALT, triglycerides, total bilirubin, total protein and blood urea were unchanged. The hypoglycemic effect of Ballota nigra extract on albino rats was further investigated by conducting a glucose tolerance test intraperitoneally (IPGTT). Healthy rats that were fasting for 18 hours followed by administration of a dose of 400 mg/kg body weight of the crude extract of Ballota nigra, orally. A significant decrease in blood glucose levels (after 15, 30, and 45 minutes) with a significant increase in serum insulin level (after 15 and 30 minute) was noted. These results suggest that, the crude extract of Ballota nigra have hypoglycemic, insulin-releasing and cholesterol lowering effects in rats.     

First Evidence of Sternal Wound Biofilm following Cardiac Surgery

Management of deep sternal wound infection (SWI), a serious complication after cardiac surgery with high morbidity and mortality incidence, requires invasive procedures such as, debridement with primary closure or myocutaneous flap reconstruction along with use of broad spectrum antibiotics. The purpose of this clinical series is to investigate the presence of biofilm in patients with deep SWI. A biofilm is a complex microbial community in which bacteria attach to a biological or non-biological surface and are embedded in a self-produced extracellular polymeric substance. Biofilm related infections represent a major clinical challenge due to their resistance to both host immune defenses and standard antimicrobial therapies. Candidates for this clinical series were patients scheduled for a debridement procedure of an infected sternal wound after a cardiac surgery. Six patients with SWI were recruited in the study. All cases had marked dehiscence of all layers of the wound down to the sternum with no signs of healing after receiving broad spectrum antibiotics post-surgery. After consenting patients, tissue and/or extracted stainless steel wires were collected during the debridement procedure. Debrided tissues examined by Gram stain showed large aggregations of Gram positive cocci. Immuno-fluorescent staining of the debrided tissues using a specific antibody against staphylococci demonstrated the presence of thick clumps of staphylococci colonizing the wound bed. Evaluation of tissue samples with scanning electron microscope (SEM) imaging showed three-dimensional aggregates of these cocci attached to the wound surface. More interestingly, SEM imaging of the extracted wires showed attachment of cocci aggregations to the wire metal surface. These observations along with the clinical presentation of the patients provide the first evidence that supports the presence of biofilm in such cases. Clinical introduction of the biofilm infection concept in deep SWI may advance the current management strategies from standard antimicrobial therapy to anti-biofilm strategy.     

Effects of Ballota nigra on glucose and insulin in alloxan-diabetic albino rats

The hypoglycemic effect of Ballota nigra extract on albino rats was investigated. Alloxan-induced diabetes mellitus was accompanied by several fold increases in plasma glucose. Administration of aqueous extract of B. nigra extract significantly reduced glucose in both healthy and diabetic rats. These results suggest that B. nigra possess hypoglycemic effects in rats and therefore, can be useful for the treatment of diabetes mellitus.     

The potential benefits of nicaraven to protect against radiation-induced injury in hematopoietic stem/progenitor cells with relative low dose exposures

Nicaraven, a hydroxyl radical-specific scavenger has been demonstrated to attenuate radiation injury in hematopoietic stem cells with 5 Gy γ-ray exposures. We explored the effect and related mechanisms of nicaraven for protecting radiation injury induced by sequential exposures to a relatively lower dose γ-ray. C57BL/6 mice were given nicaraven or placebo within 30 min before exposure to 50 mGy γ-ray daily for 30 days in sequences (cumulative dose of 1.5 Gy). Mice were victimized 24 h after the last radiation exposure, and the number, function and oxidative stress of hematopoietic stem cells were quantitatively estimated. We also compared the gene expression in these purified stem cells from mice received nicaraven and placebo treatment. Nicaraven increased the number of c-kit⁺ stem/progenitor cells in bone marrow and peripheral blood, with a recovery rate around 60–90% of age-matched non-irradiated healthy mice. The potency of colony forming from hematopoietic stem/progenitor cells as indicator of function was completely protected with nicaraven treatment. Furthermore, nicaraven treatment changed the expression of many genes associated to DNA repair, inflammatory response, and immunomodulation in c-kit⁺ stem/progenitor cells. Nicaraven effectively protected against damages of hematopoietic stem/progenitor cells induced by sequential exposures to a relatively low dose radiation, via complex mechanisms.     

Relating maximum airway dilation and subsequent reconstriction to reactivity in human lungs.

Measures of airway resistance (Raw) during deep inspiration (DI) suggest that asthmatic subjects possess stiffer, more reactive airway smooth muscle. There is evidence that one can enhance airway reactivity in healthy lungs by prohibiting DI for an extended period. The present study had two goals. First, we determined whether the maximum dilation capacity of asthmatic subjects depended on the rate of the DI. Second, we investigated whether the enhanced reactivity in healthy humans might derive from additional mechanisms not present in asthmatic subjects. For the first goal, we tracked Raw in seven healthy and seven asthmatic subjects during a noncoached DI, a DI with a 5- to 10-s breath hold at total lung capacity, and a rapid DI. We found that the minimum resistance achieved at total lung capacity was independent of the manner in which the DI was performed. For the second goal, we tracked the rate of return of Raw after a DI as well as dynamic lung elastance before and after the DI, at baseline and after bronchial challenge. A drop in lung elastance post-DI would indicate reopening of lung regions and/or reduced heterogeneities. The data show that constricted healthy but not asthmatic subjects produce longer lasting residual dilation. Hence, a portion of the enhanced reactivity in a healthy subject's response to prohibition of DIs is likely due to airway closure and/or atelectasis that can be ablated with a DI. We conclude that preventing DIs does not ensure that healthy subjects will transition entirely to an asthmatic-like hyperreactive lung state.     

The alien flora of Sudan and South Sudan: taxonomic and biogeographical composition

Biological Invasions - Studies on plant invasions depend on local and regional checklists of the alien flora. However, global overview studies have shown that some regions, including many African...