Acid Succinate Research Articles

The Antibacterial Activity and Biodegradable Properties of Biodegradable Polymers Containing a Silver-Based Antibacterial Agent

The purpose of this study is to investigate the spinnability, biodegradability and antibacterial properties of biodegradable polymers containing a silver-based antibacterial agent. The biodegradable polymers used were polybutyrene succinate (PBS) and polylactic acid (PLA). Two types of silver-based antibacterial agents, silver-based zeolite (AgZL) and silver-based zirconium phosphate (AgZR), were used. The experimental results show that the value of the weight-average molecular weight (Mw), which greatly affects the spinnability of the fiber sample, decreases with the increase in the contents of AgZL and AgZR for both PLA and PBS. The degree of the decrease in the Mw for AgZL was greater than that for AgZR because of the higher content of crystal water for AgZL. The value of antibacterial activity (R) for PLA was higher than that for PBS because of the lactic acid of PLA. AgZL was more effective in terms of antibacterial activity than AgZR in PLA and PBS fiber samples because the elution concentration of silver ions of AgZL is higher than that of AgZR from the initial stage of elution. The biodegradability of PLA and PBS increases with the increase in the content of the antibacterial agent. Especially, the hydrolysis of PLA is accelerated by the silver-based antibacterial agent. Finally, the value of R decreases as the number of washing cycles increases because the antibacterial agent falls of from the polymer surface.

Changes in the Composition of Xylem Sap during Development of the Spadix of Skunk Cabbage (Symplocarpus foetidus)

The spadix of skunk cabbage, Symplocarpus foetidus, is thermogenic and maintains an internal temperature of around 20 degrees C even when the ambient air temperature drops below freezing. This homeothermic heat production is observed only during the stigma stage, and thereafter ceases at the male stage when pollen is shed. To clarify the regulatory mechanism by which the stigma stage-specific heat production occurs in the spadix, sugars, organic acids, and amino acids in xylem sap were analyzed and compared with those of post-thermogenic plants. Interestingly, no significant difference was observed in the total volume of xylem sap per fresh weight of the spadix between thermogenic (31.2+/-24.7 microl h(-1) g(-1)) and post-thermogenic (50.5+/-30.4 microl h(-1) g(-1)) plants. However, concentrations of sugars (sucrose, glucose, and fructose), organic acids (malate and succinate), and amino acids (Asp, Asn, Glu, Gln, Gly, and Ala) in xylem sap decreased remarkably in post-thermogenic plants. Our results indicate that the composition of the xylem sap differs during the development of the spadix of S. foetidus.

Synthesis of Triterpene Derivatives of D-Glucosamine - Modified Analogs of Glycyrrhizic Acid

Triterpene D-glucosamine amides containing 18α- and 18β-glycyrrhetic acid succinates were synthesized.

Diagnosis of bacterial cerebellitis: Diffusion imaging and proton magnetic resonance spectroscopy

Diffusion-weighted imaging and in vivo proton magnetic resonance spectroscopy ((1)H magnetic resonance spectroscopy) have demonstrated great potential in differentiating intracranial lesions of various pathologies. This report describes a case of a 12-year-old child with cerebellitis and subdural empyema that manifested presence of succinate, acetate, lactate, and amino acids on in vivo (1)H magnetic resonance spectroscopy from a large area of restricted diffusion in the vermis on diffusion-weighted imaging, a finding specific for bacteria-induced infection. The child made a complete clinical and imaging recovery on conservative management.

Fabrication and Characterization of GRIN Plastic Rods Containing Silver Nanoparticles with Novel Surfmers

AbstractSummary: Both novel polymerizable surfactants of 2‐(methacroyloxy)ethyl succinate (MAES) and succinic acid mono{11‐[2‐(2‐methylacryloyloxy)ethoxy]undecyl} ester (SAME‐11) were synthesized in this investigation. A novel method was also developed for the preparation of gradient refractive index (GRIN) plastic rods containing inorganic nanoparticles with the polymerizable surfactants (surfmers). Silver nanoparticles were prepared using W/O (water in oil) reverse micelle technique in the presence of the surfmers. The effect of w values (w = [H2O]/[surfmer]), silver nitrate concentration, surfmer/isooctane/H2O ratio, and initiator concentration on the nanoparticle size was investigated. The optical absorption spectra of the micellar samples were recorded on a spectrophotometer at room temperature in the range of 200–900 nm. The nanoparticle size was confirmed with a transmission electron microcopy (TEM) technique. To introduce the nanoparticles into the GRIN plastic rods, methyl methacrylate (MMA) was used instead of isooctane in the organic phase. Nanoparticles were found to increase the refractive index of plastic rods effectively. Light scattering and an opaque appearance due to the aggregation of nanoparticles and the existence of surfactants were solved using the polymerizable surfmers in this investigation. We estimated both the real image transmission and the three dimensional refractive index distributions of the prepared GRIN plastic rods. The results of this investigation suggested that nanoparticles could be used as a kind of dopant to fabricate GRIN plastic rods and increased its refractive index effectively. Polymerizable surfactant could further raise the refractive index of the core of the GRIN rods leading to an increase of the numerical apertures (NA) and the acceptance angle (θmax) of the plastic rods.Three dimensional refractive index distribution of GRIN plastic rod prepared in this investigation.magnified imageThree dimensional refractive index distribution of GRIN plastic rod prepared in this investigation.

The pattern and kinetics of substrate metabolism of Campylobacter jejuni and Campylobacter coli.

The main aim was to investigate the patterns and kinetics of substrate oxidation by Campylobacter jejuni and C. coli. Substrate oxidation profiles by 100 strains were determined using oxygen electrode system. All the isolates tested oxidized formate, l-lactate, cysteine, glutamine and serine with high oxidation rates and high affinity but varied in their ability to oxidize citric acid cycle intermediates, aspartic acid and serine. Based on the oxidation ability of alpha-ketoglutarate, succinate, fumarate and aspartic acid, Campylobacter strains tested were divided into three distinct metabolic categories. The first group was able to metabolize alpha-ketoglutarate, succinate, fumarate and aspartic acid; the second group was unable to oxidize alpha-ketoglutarate; and the third group was unable to oxidize, succinate, fumarate, and aspartic acid. Furthermore, serine oxidation rate enabled the differentiation of C. jejuni and C. coli. Overall, the results highlights the extensive metabolic diversity between and within Campylobacter species. In addition, the kinetic data of oxidized substrates obtained may improve the isolation procedures of the organism.

Determination of Volatile Compounds in Wine by Automated Solid-Phase Microextraction and Gas Chromatography

Solid-phase microextraction in headspace mode has been applied to the determination of volatile compounds (3-methyl-1-butyl acetate, 3-methyl-1-butanol, ethyl hexanoate, pentanol, hexanol, linalool, diethyl succinate, α-terpineol, 2-phenylethyl acetate, geraniol, 2-phenylethanol and octanoic acid) in wine samples from the Denominacion de Origen Calificada Rioja using gas chromatography and a flame ionization detector. After the preliminary tests, several parameters were optimized using a Plackett-Burman design to get the most relevant variables. These parameters were: extraction time, desorption time, split ratio, magnetic stirring, type of fibre, type of injection (headspace or direct sampling) and type of salt. Five wine samples were analysed under optimum conditions. Concentrations ranging from 0.0104 mg L−1 for pentanol and 48.9 mg L−1 for 3-methyl-1-butanol were obtained. Linalool, α-terpineol and geraniol were not detected. Limit of detection ranging 0.00150-0.00800 mg L−1 and relative standard deviation ranging 1.1–5.7% were obtained.

Inhibition of experimental tobacco carcinogen induced head and neck carcinogenesis

Oral cancer models have attempted to demonstrate inhibition of oral carcinogenesis. These models used synthetic carcinogens, lacked a specific mechanism of activity or used non-physiologic doses for carcinogen or inhibitor. To correct these problems the tobacco and environmental carcinogen, dibenzo[a,l]pyrene (DB[a,l]P) (0.25%, 0.010 μM/application) was painted on the tongue and/or vitamin E acid succinate (VE as) (0.43 I.U./0.136 (μM/treatment) administered by gavages to Syrian hamsters (14 animals per group) using physiologic low doses, 5X/week. Oral cytology supplied keratinocytes after 1, 10, or 25 weeks of treatment. Cells were analyzed by flow cytometry/laser scanning cytometry. Initiation (1–6 weeks) was suppressed by reducing DNA damage (oxidation lesions: 8-oxo-dG), and repair (comet, fpg, OGG1, NTH1). Reduction in promotion (6–10 weeks) was identified by depressed proliferation (cell cycle, bromodeoxyuridine incorporation (BrdU)) and aneuploidy (propidium iodide stain). p53 and apoptosis expressions were increased (Sub G 1, mitochondrion activation: Apo 2.7, and nucleosomal formation: mebstain (TUNEL)). VE as administration reduced dysplasia (10 weeks) and oral cancer formation at 25 (0/7 vs. 5/7 DB[a,l]P) and 30 weeks (3/7 vs. 6/7 DB[a,l]P). Inhibition of oral carcinogenesis by VE as involved reversal of several cellular events that contribute towards oral cancer.

Intercalation of Vitamer into LDH and Their Controlled Release Properties

Biofunctional nanohybrids are synthesized from layered double hydroxide (LDH) and the vitamins such as ascorbic acid and topopherol acid succinate. Either ion exchange or copricipitaion leads to successful intercalation of the vitamins into gallery space of LDH that offers a new route to safe preservation of bioactivity as well as controlled release. Intercalations of vitamins are clearly reflected on the increase in the basal spacing of ZnAl-(Nitrate) LDH from 8.5 <TEX>${\AA}$</TEX> to 10.5 <TEX>${AA}$</TEX> for ascorbate, and 49.0 <TEX>${AA}$</TEX> for tocopherol acid succinate, respectively. No significant change in UV-Vis and IR absorption characteristics of the intercalated vitamins strongly supports the safe maintenance of their bioactivities without any deterioration of chemical and structural integrity. Furthermore, it is shown that the hybridized vitamins could be discharged in a controlled kinetics.

Determination of vitamin E acid succinate in biodegradable microspheres by reversed-phase high-performance liquid chromatography.

A simple, rapid, and reproducible reversed-phase high-performance liquid chromatographic (HPLC) method is applied to the routine assay of vitamin E acid succinate in biodegradable microspheres. Vitamin E acid-succinate-containing poly-(D,L-lactic-co-glycolic acid) microspheres are prepared by the solvent evaporation method. The starting drug-polymer ratio is 1:10 (w/w) and the total amount of drug and polymer processed is always 440 mg. The content of vitamin E acid succinate in the microspheres is evaluated by HPLC. Chromatography is carried out isocratically at 25 degrees C +/- 0.5 degrees C on an Extrasil ODS-2 column with a mobile phase composed of methanol-water (97:3, v/v) (pH 5.6) at a flow rate of 2 mL/min and UV detection at 284 nm. Parameters such as linearity, limits of quantitation (LOQ) and detection (LOD), precision, accuracy, recovery, specificity, and ruggedness are studied as reported in the International Conference on Harmonization guidelines. The stability of vitamin E acid succinate is also studied with satisfactory results after 48 h at 25 degrees C. The method is selective and linear for drug concentrations in the range 15-210 micro g/mL. The LOQ and LOD are 15 and 3 micro g/mL, respectively. The results for accuracy studies are good. Values for coefficient of variation for intra- and interassay are 2.08% and 2.32%, respectively. The mean percentage of vitamin E acid succinate in the recovery studies is 99.52% +/- 0.81%. The mean loading efficiency for microspheres is 96.53% +/- 1.31%.

Fatty acids and glucose increase neutral endopeptidase activity in human microvascular endothelial cells.

Neutral endopeptidase (NEP), a membrane-bound metallopeptidase enzyme that degrades neuropeptides, bradykinin, atrial natriuretic factor, enkephalins, and endothelin may regulate response to injury. We have previously demonstrated increased NEP localization and enzyme activity in diabetic wounds and skin compared with normal controls. We hypothesized that hyperlipidemia and hyperglycemia associated with type 2 diabetes mellitus may induce excessive NEP activity and thereby diminish normal response to injury. Human microvascular endothelial cells were treated with five different fatty acids (40 microM) with varying degrees of saturation, including oleic acid, linoleic acid, palmitic acid, stearic acid, and linolenic acid and/or glucose (40 mM) for 48 h. The effect of the antioxidative agents vitamin E and C on NEP enzyme activation was determined by treating the cultured cells with alpha-tocopherol succinate and/or L-ascorbic acid. Cell membrane preparations were assayed for NEP activity by incubation with glutaryl-Ala-Ala-Phe-4-methoxy-beta naphthylamide to generate a fluorescent degradation product methoxy 2 naphthylamine. High glucose or fatty acid concentration upregulated NEP activity. The highest NEP activity was observed with combined elevated glucose, linoleic acid, and oleic acid (P < 0.05). Antioxidant vitamin E and C treatment significantly reduced NEP enzyme activity after fatty acid exposure (P < 0.05). Thus, hyperglycemia and hyperlipidemia associated with type 2 diabetes mellitus may increase endothelial cell NEP activity and thereby decrease early pro-inflammatory responses. The modulator effect of vitamin E and C on NEP membrane enzyme activity after exposure to fatty acid stimulation suggests that lipid oxidation may activate NEP.

Control of inducer accumulation plays a key role in succinate-mediated catabolite repression in Sinorhizobium meliloti.

The symbiotic, nitrogen-fixing bacterium Sinorhizobium meliloti favors succinate and related dicarboxylic acids as carbon sources. As a preferred carbon source, succinate can exert catabolite repression upon genes needed for the utilization of many secondary carbon sources, including the alpha-galactosides raffinose and stachyose. We isolated lacR mutants in a genetic screen designed to find S. meliloti mutants that had abnormal succinate-mediated catabolite repression of the melA-agp genes, which are required for the utilization of raffinose and other alpha-galactosides. The loss of catabolite repression in lacR mutants was seen in cells grown in minimal medium containing succinate and raffinose and grown in succinate and lactose. For succinate and lactose, the loss of catabolite repression could be attributed to the constitutive expression of beta-galactoside utilization genes in lacR mutants. However, the inactivation of lacR did not cause the constitutive expression of alpha-galactoside utilization genes but caused the aberrant expression of these genes only when succinate was present. To explain the loss of diauxie in succinate and raffinose, we propose a model in which lacR mutants overproduce beta-galactoside transporters, thereby overwhelming the inducer exclusion mechanisms of succinate-mediated catabolite repression. Thus, some raffinose could be transported by the overproduced beta-galactoside transporters and cause the induction of alpha-galactoside utilization genes in the presence of both succinate and raffinose. This model is supported by the restoration of diauxie in a lacF lacR double mutant (lacF encodes a beta-galactoside transport protein) grown in medium containing succinate and raffinose. Biochemical support for the idea that succinate-mediated repression operates by preventing inducer accumulation also comes from uptake assays, which showed that cells grown in raffinose and exposed to succinate have a decreased rate of raffinose transport compared to control cells not exposed to succinate.

Toxicity Study of Diethyl Phthalate on Freshwater Fish Cirrhina mrigala

Diethyl phthalate (DEP) is used as a plasticizer, a detergent base, in aerosol sprays, as a perfume binder in incense sticks and after-shave lotions. It is known to be a contaminant of freshwater and marine ecosystems. Therefore, a study was designed to determine the toxic effects of DEP on a freshwater fish, Cirrhina mrigala. The fish was treated with 25, 50, 75, and 100ppm (w/v) DEP dissolved in acetone to determine the LC 50. Positive controls were treated with acetone only. There was 100− mortality observed within 24 h in 75 and 100 ppm, and 50− mortality in 50 ppm treated fish in 72 h. Those treated at 25 ppm showed only 10− mortality within 72 h and remaining fish continued to survive. The surviving fish were treated with 25 ppm DEP once daily for 3 days with every change of water (Group III). One group was maintained as negative control in dechlorinated water (Group I) and the other group received acetone once daily for 3 days with every change of water and was used as positive control (Group II). Fish were killed by cold narcosis on an ice block and dissected to obtain liver, muscle, and brain samples; 10% homogenates in ice-cold saline were prepared. Brain and muscle acetylcholinesterase (AchE) activity was measured. Liver aspartate (AST) and alanine aminotransferase (ALT), and liver and muscle succinate dehydrogenase (SDH) alkaline and acid phosphate (ALP and ACP) were measured. There was a significant increase in liver and muscle ACP and ALP in DEP-treated fish compared with positive and negative controls. There was a significant increase in muscle SDH and liver ALT (ALT) in DEP-treated fish compared with positive and negative controls. Brain AchE level was significantly decreased in DEP-treated fish compared to positive and negative controls. These results indicate that DEP brings about significant changes in the activity of certain liver and muscle enzymes. These alterations in enzyme activity may have long-term effects on that are continuously exposed to low doses of DEP in the aquatic environment.

Escherichia coli high-cell-density culture: carbon mass balances and release of outer membrane components.

Carbon mass balances were calculated in fed-batch cultures of E. coli W3110, using mineral medium with glucose as the limiting substrate. The carbon recovery, based on biomass, CO(2), and acetate was approximately 90% at the end of the culture (25 h, 27 g L(-1) dw). The missing carbon remained as soluble organic compounds in the medium. Outer membrane (OM) constituents, such as lipopolysaccharides (LPS), phospholipids (PL), and carbohydrates (each at approximately 1 g L(-1)) contributed to 63% of the extracellular carbon. The amount of released LPS and PL equaled the total amount of OM bound to the cells in the culture. Small amounts of DNA and protein detected in the medium indicated that no cell lysis had occurred. Acetate, lactate, ethanol, formate, succinate and amino acids (Glu, Gln, Asp, Asn, Ala, Gly, Ser) were detected in the culture medium, but made up only a few percent of the extracellular carbon mass. The remaining 30% was not identified, but was assumed to constitute complex carbohydrates.

Cyclosporine A-induced toxicity in two renal cell culture models (LLC-PK1 and MDCK).

Renal damage caused by therapeutic treatment with cyclosporine A has been well documented. Clinical experiences have shown that cyclosporine A nephrotoxicity is determined by interstitial fibrosis with tubular atrophy. However, the exact mechanism by which this drug causes nephrotoxicity has not yet been clarified. This study used an in vitro model in an attempt to identify the cellular mechanisms underlying kidney cyclosporine A damage. We used two cell lines with the characteristics of proximal and distal tubule cells (pig kidney proximal tubular epithelial cell line [LLC-PK1] and Madin-Darby canine kidney cell line [MDCK]. The cell lines were treated with cyclosporine A for 24 h. After the treatment, the cells were stained with Trypan Blue to estimate cell viability and processed by histochemical reactions to evaluate their cellular metabolism. Four enzymes (acid phosphatase, alkaline phosphatase, lactate dehydrogenase and succinate dehydrogenase) were considered. The cell viability assay showed that the LLC-PK1 cell line was more sensitive to cyclosporine A than MDCK. Remarkably, the LLC-PK1 cells disappeared with cyclosporine A treatment. As for the hydrolytic enzymes, only acid phosphatases showed an increased positivity in the treated LLC-PK1 cells. Similarly, lactate dehydrogenase showed a different activity histochemically. No statistically significant alterations were observed in the succinate dehydrogenase reaction. The cyclosporine A-treated MDCK cell lines did not show any difference in either their hydrolytic or succinate dehydrogenase enzyme positivity with respect to the control line. In contrast, there was a significant increase in lactate dehydrogenase activity. This study allowed the possible mechanism of cyclosporine A-induced damage in renal tubular cells to be evaluated. The enzymatic changes happened rapidly (during the 24 h of treatment), suggesting that this alteration was one of the steps by which cyclosporine A induced toxicity. Moreover, since acid phosphatase is a marker of protein catabolism, the variation in the activity of this enzyme, in the LLC-PK1 line only, showed that cyclosporine can induce alterations leading to cellular toxicity. The modifications in lactate dehydrogenase activity, in both lines, suggested that this drug caused cell stress, inducing the production of lactic acid from glucose in the presence of oxygen. In conclusion, cyclosporine A treatment may force LLC-PK1 and MDCK cells to use anaerobic glycolysis preferentially. Further, these enzyme alterations may represent an epiphenomenon or a consequence of cyclosporine A toxicity.

Retinoic Acid and Vitamin E Modulate Expression and Release of CD178 in Carcinoma Cells: Consequences for Induction of Apoptosis in CD95-Sensitive Cells

CD178 (CD95-ligand) is expressed on several tumor cells and likely influences the interaction of the tumor with the host immune system. However, little is known about the mechanisms that regulate its expression on the cell surface. We have evaluated the ability of various compounds and cytokines to regulate cell surface expression and release of soluble CD178 in various carcinoma cell lines. Vitamin E succinate (VES) and retinoic acid (RA) were found to reduce CD178 surface expression, whereas interferon-γ stimulated a slight upregulation. At 48 h, the regulation of surface CD178 by VES and RA arose from a small decrease in CD178 mRNA and to a greater extent due to an increase in the release of soluble CD178; the latter was blocked by addition of a metalloproteinase inhibitor. Accordingly, VES and RA treatment diminished the ability of tumor cells to kill CD95-sensitive cells and this effect was markedly reduced by the presence of a metalloproteinase inhibitor. Our results indicate that, in vitro, CD178 expression on the cell surface of tumor cells can be regulated by agents that alter both expression and release of the ligand. In vivo, such treatments may play an important role in the outcome of tumor sensitivity or resistance to host immune mechanisms.

Effect of environmental and chemotactic stimuli on the activity of the Campylobacter jejuni flaA sigma(28) promoter.

The effect of environmental and chemotactic stimuli was assessed using a fusion between the Campylobacter jejuni flaA sigma(28) promoter and a promoterless luxCDABE cassette on pRYluxCDABE. Environmental stimuli relevant to the enteric environment were found to modulate flaA promoter activity. pH, bovine bile, deoxycholate, L-fucose and osmolarity up-regulated the flaA promoter while viscosity resulted in down-regulation. C. jejuni chemotactic effectors, including the amino acids aspartate and glutamate and the organic acids citrate, fumarate, alpha-ketoglutarate and succinate up-regulated the flaA promoter. Proline, which does not elicit a chemotactic response, up-regulated the flaA promoter.

Gamma-irradiation stability of saturated and unsaturated aliphatic polyanhydrides--ricinoleic acid based polymers.

The effect of terminal sterilization by gamma-irradiation on several ricinoleic acid based polyanhydrides was investigated. The following polymers were used: poly(ricinoleic acid maleate) [P(RAM)], poly(ricinoleic acid succinate) [P(RAS)], poly(hydroxy stearic acid succinate) [P(HSAS)], poly(hydroxy stearic acid maleate) [P(HSAM)], and their copolymers with sebacic acid. The polymers were irradiated with an absorbed dose of 2.5 or 10 Mrad by means of a 60Co source under dry ice or at room temperature. No differences were found between samples irradiated under dry ice and at room temperature. Polymers prepared from monomers containing maleate residues, which contain double bonds adjusted to the anhydride linkage along the polymer chain, decreased in molecular weight, became insoluble, and showed fast hydrolytic degradation. For example, p(RAM), p(HSAM), and their copolymers with sebacic acid decreased in Mw from about 10,000 to about 2000, and from about 30,000 to about 5000, respectively, while polymers based on RAS and HSAS remained stable. This phenomenon was explained by an anhydride interchange-self-depolymerization process of the unsaturated anhydride bonds induced by gamma-irradiation. This explanation was supported by the depolymerization of another class of polymers having an anhydride bond between two double bonds, fumaric acid anhydride polymers. The anhydride bond that lies between two double bonds was found to be more sensitive to gamma-irradiation. This anhydride bond may be cleaved to form two radicals that further react with aliphatic anhydride bonds along the polymer chain to form inter- and/or intracyclization products.

Neuroprotective effect of vitamin E on the early model of Parkinson’s disease in rat: behavioral and histochemical evidence

There is strong evidence that oxidative stress participates in the etiology of Parkinson’s disease (PD). We designed this study to investigate the neuroprotective effect of vitamin E in the early model of PD. For this purpose, unilateral intrastriatal 6-hydroxydopamine (12.5 μg/5 μl) lesioned rats were pretreated intramuscularly with d-α-tocopheryl acid succinate (24 I.U./kg, i.m.) 1 h before and three times per week for 1 month post-surgery. Apomorphine- and amphetamine-induced rotational behavior was measured postlesion fortnightly. A parallel tyrosine hydroxylase immunoreactivity and wheat germ agglutinin-horse radish peroxidase (WGA-HRP) tract-tracing study was performed to evaluate the vitamin E pretreatment efficacy. Tyrosine hydroxylase-immunohistochemical analyses showed a reduction of 18% in ipsilateral substantia nigra pars compacta (SNC) cell number of the vitamin E-pretreated lesioned (L+E) group comparing with contralateral side. The cell number dropped to 53% in the lesioned (L+V) group. In addition, retrograde-labeled neurons in ipsilateral SNC were reduced by up to 30% in the L+E group and 65% in the L+V group. Behavioral tests revealed that there are 74% and 68% reductions in contraversive and ipsiversive rotations in the L+E group, respectively, as compared with the L+V group. Therefore repeated intramuscular administration of vitamin E exerts a rapid protective effect on the nigrostriatal dopaminergic neurons in the early unilateral model of PD.

Intestinal metabolism after ischemia-reperfusion

Purpose: This study explores the effects of ischemia-reperfusion on various metabolic aspects of the small intestine. Methods: Intestinal ischemia-reperfusion was obtained by clamping and unclamping the superior mesenteric artery in adult rats. Four groups of animals were studied: (A) sham operation for 150 minutes, (B) 90-minute intestinal ischemia, (C) 150-minute intestinal ischemia, and (D) 90-minute intestinal ischemia followed by 60-minute reperfusion. Body temperature was maintained at normothermia (36.5 to 37.5°C). Concentrations of intestinal glucose, succinate, lactate, amino acids, phosphocholine (PC), glycerophosphocholine (GPC), choline, and phosphoenergetics were measured using magnetic resonance spectroscopy of freeze-clamped small intestine extracts. Results: Intestinal ischemia (groups B and C) alone caused a significant drop in glucose and phosphoenergetics but caused an increase in amino acids, succinate, and lactate. Ischemia and ischemia-reperfusion decreased PC and GPC but increased choline. After intestinal reperfusion (group D), no recovery of phosphoenergetics was observed, but there was partial recovery of glucose, succinate, lactate, and amino acids. Conclusions: There is no recovery of phosphoenergetics after 90 minutes of intestinal ischemia followed by 60 minutes of reperfusion. Partial recovery of glucose, succinate, lactate, and amino acids may reflect equilibration of these metabolites between damaged cells and extracellular fluid. J Pediatr Surg 35:759-764. Copyright © 2000 by W.B. Saunders Company.