Reconstruction of parietal bone defects with adiposederived mesenchymal stem cells. Experimental study

Purpose:This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration.Methods:Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter.Results:There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05.Conclusions:Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.Key words: Bone Regeneration, Platelet-Rich Plasma, Tissue Engineering, Rats     

Nitric oxide as a mediator of the laxative action of magnesium sulphate.

1. Magnesium sulphate was studied for its effects on diarrhoea, fluid secretion, gastrointestinal transit and nitric oxide (NO) synthase activity in rats. 2. At a dose of 2 g kg-1 orally magnesium sulphate produced diarrhoea that was delayed in onset and intensity in a dose-related manner by the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). This was prevented by the NO precursor, L-arginine and the NO donating compound, isosorbide-5-mononitrate (IMN). 3. Nitric oxide synthase activity was stimulated in gut tissue from rats given magnesium sulphate and this was inhibited by L-NAME. Dexamethasone (1 mg kg-1, i.p.), an inhibitor of inducible NO synthase, had no effect on magnesium sulphate-induced diarrhoea. 4. Magnesium sulphate stimulated fluid and electrolyte accumulation in the intestinal lumen; these effects were prevented by L-NAME but not D-NAME. 5. Gastrointestinal transit of a non-absorbable marker (charcoal suspension) was increased by oral magnesium sulphate from a mean value of 54.1% to 72.9% (P < 0.01), and this was prevented by pretreatment with L-NAME. 6. The results demonstrate that oral magnesium sulphate produces diarrhoea in rats by increasing the accumulation of fluid in the intestinal lumen and enhancing flow from the proximal to distal intestine. The mechanism involves release of NO, probably through stimulation of the constitutive form of NO synthase. Whether or not the effects of magnesium sulphate are due to an osmotic action or an intrinsic effect of the magnesium or sulphate ions cannot be determined from these experiments.     

Update on treatment of pediatric pain with surgical considerations

The assessment, treatment, and prevention of pediatric pain pose a special challenge to surgeons and others involved in the care of children. The experience of pain is subjective, and infants and many children are unable to verbalize their level of discomfort. Therefore, it is the responsibility of physicians and nurses to be educated and trained to identify nonverbal signs of pain and discomfort, anticipate the experience of pain associated with specific procedures and diagnoses, and initiate the appropriate use of analgesics as well as nonmedicinal strategies to relieve this pain.     

Experimental axonopathy induced by immunization with campylobacter jejuni lipopolysaccharide from a patient with guillain‐barré syndrome

Campylobacter jejuni (C. jejunj) infection is the most common antecedent in the axonal variant of Guillain‐Barré syndrome (GBS). Antibodies against nerve gangliosides found in GBS patients recognize cross‐reactive epitopes in the lipopolysaccharide (LPS) of C. jejuni. This led to the molecular mimicry hypothesis of GBS. We immunized eleven rabbits with a LPS extracted from HS:19 C. jejuni strain isolated from a patient with GBS and complete Freund's adjuvant (CFA)(group I). In a second experiment we immunized seven rabbits with LPS, CFA and keyhole limpet hemocyanin (KLH)(group II). All group I rabbits developed high titers of anti‐LPS, anti‐GM1, anti‐GD1b antibodies and lower titers of anti‐GD1a. One rabbit, 50 days after initial inoculation, showed tremor and weakness. All rabbits of group II developed high titres of antiganglioside antibodies and six animals showed weakness 59–113 days after initial inoculation. Two rabbits died. Pathology showed mild to moderate, tendentially grouped, axonal degeneration in sciatic nerves of four out of five animals. Control rabbits of group I (immunized with CFA only) did not develop antibodies, controls of group II (immunized with CFA + KLH) developed low titers of IgG anti‐GM1. None developed neurological signs or showed axonal degeneration. C. jejuni LPS is a potent B‐cell stimulator capable to induce a strong antiganglioside response in rabbits. However, to induce the neuropathy is crucial to employ KLH, a glycoprotein known to stimulate both humoral and cellular responses. This animal model reproduces the pathogenetic process hypothesized in axonal GBS with antiganglioside antibodies post C. jejuni infection.     

Anaerobic threshold and performance in middle and long distance running.

A total of 112 endurance athletes, divided in three groups according to their age, were selected considered in this study. Thirtythree randomly subjects (11 per each age group) were both laboratory--and field--tested for anaerobic threshold (AT) determination. The running speed (RS) and heart rate (HR) at which AT occurred were highly correlated in the two conditions, with R ranging from 0.82 to 0.90, with the highest correlation for the oldest group. All the athletes participated a series of competition races at various distances, and the correlation between RS at AT and actual racing RS was calculated. It was found that RS at AT is highly correlated with racing RS for distances from 5 km and above, with the highest correlation found in the 10 km race for the 12-18 years and the 19-30 years age groups, and for the one hour race for the oldest group. Shorter distances (e.g. 800 m) did not show significant correlation with RS at AT, and this was particularly evident for the oldest group (R = 0.30).     

Castor oil increases intestinal formation of platelet-activating factor and acid phosphatase release in the rat.

1. When castor oil was administered by gavage to rats, the duodenum and jejunum but not ileum and colon produced large amounts (5-6 fold greater than control) of platelet activating factor (Paf). 2. Intraluminal release of acid phosphatase (AP) was also markedly increased (5-6 fold greater than control) in the duodenum and jejunum of castor oil-treated rats and there was a correlation between the elevated release of AP and intestinal hyperaemia. 3. These findings support a role for Paf as a mediator of intestinal damage induced by castor oil.     

Porins and lipopolysaccharide stimulate platelet activating factor synthesis by human mesangial cells.

Porins, a family of hydrophobic proteins located in the outer membrane of the cell wall of gram-negative bacteria and lipopolysaccharide (LPS), were shown to stimulate the synthesis of platelet activating factor (PAF), a phospholipid mediator of inflammation and endotoxic shock, by cultured human glomerular mesangial cells (MC). The synthesis of PAF induced by porins was rapid (peak at 20 min) and independent either from contamination by LPS or from generation of an endotoxin-induced cytokine such as tumor necrosis factor (TNF) since it was not prevented by cycloheximide, an inhibitor of protein synthesis or anti-TNF blocking antibodies. LPS also stimulated PAF synthesis by MC. However, the kinetic of PAF synthesis induced by LPS was biphasic with an early and transient peak at 10 minutes and a second and sustained peak at three to six hours. This second peak required an intact protein synthesis and was prevented by anti-TNF antibodies, suggesting the dependency on LPS-induced synthesis of TNF. Experiments with labeled precursors demonstrated that in MC, either after stimulation with porins or LPS, PAF was synthesized via the remodeling pathway that involves acetylation of 1-0-alkyl-sn-glyceryl-3-phosphorylcholine (2-lyso-PAF) generated from 1-0-alkyl-2-acyl-sn-glyceryl-3-phosphorylcholine by phospholipase A2 (PLA2) activity. Porins and LPS, indeed, induced PLA2-dependent mobilization of [14C]-arachidonic acid that was inhibited by p-bromodiphenacylbromide (PBDB). PBDB, an inhibitor of PLA2, also blocked PAF synthesis by preventing the mobilization of 2-lyso-PAF, the substrate for PAF-specific acetyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibitory action of quercetin on intestinal transit in mice

The effects of quercetin have been investigated on the gastrointestinal propulsion of charcoal meal in mice. Quercetin reduced the rate of intestinal transit and this effect was potentiated by verapamil.