Isolation and Identification of Cytotoxic Compounds Present in Biomaterial Life®

Direct pulp capping consists of a procedure in which a material is directly placed over the exposed pulp to maintain dental vitality. Although still widely used in clinical practice, previous in vitro studies found that the biomaterial Life^® presented high cytotoxicity, leading to cell death. This study aimed to identify the Life^® constituents responsible for its cytotoxic effects on odontoblast-like cells (MDPC-23). Aqueous medium conditioned with Life^® was subjected to liquid–liquid extraction with ethyl acetate. After solvent removal, cells were treated with residues isolated from the organic and aqueous fractions. MTT and Trypan blue assays were carried out to evaluate the metabolic activity and cell death. The organic phase residue promoted a significant decrease in metabolic activity and increased cell death. On the contrary, no cytotoxic effects were observed with the mixture from the aqueous fraction. Spectroscopic and spectrometric methods allowed the identification of the toxic compounds. A mixture of the regioisomers ortho, para, and meta of N-ethyl-toluenesulfonamide was identified as the agent responsible for the toxicity of biomaterial Life^® in MDPC-23 cells. These findings contribute to improving biomaterial research and development.     

Severe and protracted diarrhea: results of the 3-year SIGEP multicenter survey. Working Group of the Italian Society of Pediatric Gastroenterology and Hepatology (SIGEP).

BACKGROUND: The spectrum of severe and protracted diarrhea (SPD), previously defined as intractable diarrhea, has changed during the past several decades. Despite recent advances in determining the cause of SPD and in treatment, this syndrome still represents a challenge and is becoming a major problem affecting health care resources. This study was conducted to characterize the epidemiology, spectrum of causes, and the outcome of SPD in Italy in recent years. METHODS: All the SPD cases seen at the major centers of pediatric gastroenterology in Italy during a 3-year period (1993-1996) were recruited in this multicenter, prospective survey. RESULTS: Thirty-two children (26 boys and 6 girls; median age at the onset of SPD, 40 days) were enrolled in this study by 9 of 26 participating centers. Twelve were newly diagnosed cases, with an estimated SPD incidence rate in Italy of 0.64 to 0.92 x 10(-5) infants per year. The most common causes were autoimmune enteropathy (n = 8) and ultrastructural abnormalities of the enterocyte (n = 7), whereas food intolerance and postenteritis syndrome were less frequent (3 and 2 cases, respectively). Two children with autoimmune enteropathy fulfilled the criteria for the X-linked variant of this condition. At the end of the study period, 9 of 31 patients had recovered, 15 still had diarrhea, and 7 had died. CONCLUSIONS: Severe and protracted diarrhea is a rare but challenging problem in Italy. Because parenteral nutrition or intestinal transplantation are the only options in a subset of cases (e.g., ultrastructural abnormalities of the enterocyte), infants with SPD should be referred to specialized centers where advanced diagnostic and therapeutic facilities are available.     

Diethylcarbamazine citrate, an antifilarial drug, stimulates human granulocyte adherence.

Incubation with diethylcarbamazine citrate caused significant augmentation of human neutrophil and eosinophil adherence to tissue culture plastic. This effect was dose dependent and cell dependent, with eosinophils showing greater sensitivity and a greater adhesive response to the drug than did neutrophils. Eosinophils preincubated with diethylcarbamazine citrate demonstrated decreased adhesive responses to other adherence-augmenting stimuli. Use of Fc-treated plastic augmented diethylcarbamazine citrate-stimulated neutrophil (but not eosinophil) adherence. Direct stimulation of host effector cell adherence may explain, in part, the therapeutic action of diethylcarbamazine citrate in vivo.     

Renal hemodynamics, plasma amino acids and hormones after a meat meal in progressive nephron loss

Ten patients with chronic renal failure (GFR 29-97 ml/min), on free diets providing 1 g/kg B.W. of proteins, ingested an oral protein load (meat meal, 2 g/kg B.W.). GFR and RPF increased significantly over baseline with no change in filtration fraction. Within 30 min of the meal and for the next 3 h a statistically significant increase was observed in the plasma concentrations of the following amino acid groups: essential, non-essential, total, branched-chain, ketogenic, glycogenic, glycogenic and ketogenic, basic, acid, polar and non-polar. At 30 min the smallest increase was seen in acid and polar amino acids (6.7% and 7.6%, respectively). At 180 min the largest increase (78.8%) was seen for glycogenic and ketogenic amino acids and total plasma amino acids were 1.58 times baseline. After the meat meal plasma glucagon and insulin rose significantly, while growth hormone, plasma renin activity and aldosterone did not vary.     

Electron paramagnetic resonance analysis of the distribution of a hydrophobic spin probe in suspensions of humic acids, hectorite, and aluminum hydroxide-humate-hectorite complexes

Until recently, there were no techniques capable of direct observation of the microscale locations where nonpolar organic compounds accumulate when associated with natural geosorbents. The ability of electron paramagnetic resonance (EPR) spectroscopy to monitor and elucidate directly the different molecular-scale environments of paramagnetic spin probes has been demonstrated lately in model soils, yet it remains untested in complex systems. In this general context, the present investigation was aimed at assessing the extent to which EPR could be used to monitor the sorption of 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy benzoate (TEMPO benzoate), a hydrophobic spin probe, on a smectite (hectorite), two humic acids, and their complexes in the presence or absence of aluminum hydroxide. Results demonstrate that EPR is able to monitor easily adsorption on these sorbents in batch-style experiments. Distribution coefficient (Kd) values of 455.4 and 483.1 ml/g were found for the adsorption of TEMPO benzoate on hectorite-humic acids complexes, compared to respective Kd values of 46 and 147 ml/g predicted solely on the basis of the mass of humic acids present in the complexes. These observations confirm the significant role of hectorite for the sorption of hydrophobic compounds, together with humic acids, contrary to common belief that emphasizes the almost exclusive sorptive role of organic matter. In addition, for the first time, EPR is able to provide evidence that hydrophobic molecules in the presence of geosorbents can segregate in multimolecular clusters that are in equilibrium with aqueous probe concentrations below the probe's solubility threshold. Possible consequences of this clustering process in terms of the fate and transport of hydrophobic compounds in subsurface environments are discussed.     

Acute thanol effect on chemotaxis and other components of host defense.

The effect of alcohol on granulocyte chemotaxis was studies with a radioactive assaysystem. Chemotaxis was inhibited in vitro by concentrations of alcohol above 400 mg. per cent when present during all steps in the assay, but levels above 800 mg. per cent required for inhibition when alcohol was present only during the granulocyte incubation.No inhibition of chemotactic factor generation was found with alcohol concentration up to 1,500 mg. per cent. Cells and serum exposed to alcohol in vivo by acute intxication of donors demonstrated normal in vitro chemotactic performance, even when the assay itself was carried out in medium containing 200 mg. of alcohol. Thestudies do not exclude alcohol's in vivo induction of an inhibitor which must remain present during chemotaxis for inhibition; nor would they have detected an impairment of chemotaxis occurring after the peak blood alcohol concentration. The intoxicated volunteer subjects were also evaluated for changes in delayed hypersensitivity, serum complement concentration, granulocyte hexose monophosphate shunt activity, and circulating whiteblood cell counts; no consistent changes were seen.