Effects of pravastatin on cellular ultrastructure and hemorheology in rats after traumatic head injury.

Pravastatin has neuroprotective effects against aging but its role in brain injury remains unclear. This study evaluated the effects of pravastatin on the ultrastructural changes and hemorheological parameters in rats after traumatic brain injury (TBI) of right parietal cortical contusion by a controlled weight-dropping method. There were three groups: (I) Sham operated group; (II) TBI + vehicle (saline) group; and (III) TBI + pravastatin group. Right parietal craniectomy was performed in all groups. In TBI + pravastatin group, pravastatin was administered orally at a dose of 1 mg/kg every day for 7 days starting at 24 hours after the injury. Plasma viscosity, erythrocyte deformability and erythrocyte aggregation were measured from blood samples of all rats on 2nd, 7th and 15th days. At the same time electron microscopic study was done on designated days for groups II and III. Treatment with pravastatin markedly increased aggregation amplitude and γIsc max values and significantly decreased erythrocyte deformability but did not change plasma viscosity in 2 weeks time. Ultrastructural parameters such as perinuclear edema, mitochondrial swelling and intraneuronal vacuoles were detected in lower degree in the statin group when compared to the saline group, especially decreased demyelinization and endothelial detachment was prominent. As a result, the hyperviscosity state with increased erythrocyte aggregation and decreased erythrocyte deformability induced by pravastatin in this study was accompanied by an improvement of the ultrastructural findings in TBI. This hyperviscosity state may be a compensatory mechanism to increase the oxygenation of the injured tissue by inducing the release of antiaggregant and vasodilatory substances by increasing shear stress. Therefore, we suggest that prolonged pravastatin usage may exert affirmative effects on traumatic brain injury conditions by increasing blood viscosity.

Microscopic and electrophysiological changes on regenerating sciatic nerves of rats treated with simvastatin.

UNLABELLED: Simvastatin is a hypocholesterolemic agent presumed to cause peripheral neuropathy. We arranged an experimental design which focuses on the effect of simvastatin on peripheral nerves and neural regeneration. Sciatic nerve injury was performed at midthigh region of male wistar rats either by clamp compression or fine cut. Electrophysiological and electron microscopical studies were carried out to assess the effect of simvastatin on peripheral nerve and nerve regeneration. There was no difference between the groups that were given simvastatin and standard regimen in the sciatic nerve when electrophysiological measurements were concerned. However, some of the rats that were given simvastatin show reduction in axoplasm density (intensity) of myelinated nerve fibers and prominent vacuolization of myelin sheath according to light and electron microscopic studies. Sciatic nerve compound muscle activation potential measurements of the animals given simvastatin showed that this drug doesn't have a delaying effect on the peripheral nerve recovery time. Electrophysiological measurements showed that simvastatin did not influence nerve regeneration however it was found to induce severe vacuolization of myelin sheath of the sciatic nerve. It was apparent that the drug induces some form of structural dysfunction as myelin changes supported by electron microscopical studies. CONCLUSION: simvastatin was shown to delay regeneration as shown in microscopic studies but still there was no influence on nerve regeneration.

Morphological evaluation of rat incisor enamel and dentin induced by pregnancy and lactation using a scanning electron microscope.

This study assessed the effects of pregnancy and lactation on the morphology of the dentine tubules and external enamel surface of rat incisor teeth using a scanning electron microscope (SEM) equipped with an energy dispersive x-ray (EDX) system. Twenty-four female Wistar rats were divided into three groups; group A rats were at the end of pregnancy, group B rats were in the post-lactation period and group C rats, the control group, were unmated. The outer enamel surface and openings of the dentine tubules at the neck regions of the incisors were observed under the SEM and photographed. Examination of the incisor teeth of pregnant and post-lactation rats revealed scratches on the enamel surface. There were few eroded areas and slight changes and the dentine tubules of the pregnant group were fully or partially occluded on the entire surface of the enamel in the lactating rats. Almost all dentine tubules of the rats in this group were open. During the study, EDX analysis of calcium, phosphate and magnesium was also performed at 20 kV and 0 degree tilt. The results of EDX analyses of magnesium were significantly lower in the pregnant group compared with the lactation and control groups for the dentine in the neck region (p<0.05). The calcium values increased in the lactation group compared with those of the rats in the other two groups (p<0.05). These results might indicate that changes during pregnancy and lactation affect the content and morphology of mineralized dental hard tissue.

Electron microscopic examination of the anterior lens capsule in a case of Alport's syndrome.

PURPOSE: To report a case of Alport's syndrome and to present electronmicroscopic examination findings of the anterior lens capsule of this patient. METHOD: A 21-year-old man was referred for low visual acuity and retinal pigment epithelial changes in the left eye. The patient and his relatives underwent detailed ophthalmological examination, including electrophysiological testing. The patient also underwent electronmicroscopic examination of the anterior lens capsule. RESULTS: His visual acuity was 6/18 OD and 6/15 OS. Anterior lenticonus and subcapsular opacities were observed in the left eye. Cataract extraction by phacoemulsification with intraocular lens implantation was performed for his poor visual performance. During the capsulorhexis, the remarkably thin and fragile anterior capsule was noted and removed. Ultrastructural analysis of the anterior lens capsule showed a thinner central zone compared with the periphery. CONCLUSIONS: The course of Alport's syndrome can be ameliorated by early diagnosis. Therefore, the ophthalmological examination of a patient with anterior lenticonus must be combined with a detailed medical evaluation. Ultrastructural analysis of the lens capsule can support the diagnosis of Alport's syndrome.

Macroporous monolithic gels, cryogels, with immobilized phages from phage-display library as a new platform for fast development of affinity adsorbent capable of target capture from crude feeds.

Selected phage clones expressing a peptide with high binding affinity for recombinant human lactoferrin or von Willebrand factor (vWF) were covalently coupled to macroporous poly(dimethylacrylamide) monolithic column. Large pore size (10-100 microm) of macroporous poly(dimethylacrylamide) makes it possible to couple long (1 microm) phage particles as ligands without any risk of blocking the monolithic column. The macroporous monolithic columns were successfully used for the direct affinity capture of target proteins from particulate containing feeds like milk containing casein micelles and fat globules (1-10 microm in size) or even whole blood containing blood cells (up to 20 microm in size). The newly developed platform based on selected bacteriophages immobilized within macropores of the monolithic cryogels presents a convenient alternative to antibodies for fast and selective development of the specific adsorbent.

Hydroxyl functionalized thermosensitive microgels with quadratic crosslinking density distribution.

N-isopropylacrylamide (NIPA) based uniform thermosensitive microgels were synthesized by dispersion polymerization by using relatively hydrophilic crosslinking agents with hydroxyl functionality. Glycerol dimethacrylate (GDMA), pentaerythritol triacrylate (PETA) and pentaerythritol propoxylate triacrylate (PEPTA) were used as crosslinking agents with different hydrophilicities. A protocol was first proposed to determine the crosslinking density distribution in the thermosensitive microgel particles by confocal laser scanning microscopy (CLSM). The microgels were fluorescently labeled by using hydroxyl group of the crosslinking agent. The CLSM observations performed with the microgels synthesized by three different crosslinking agents showed that the crosslinking density exhibited a quadratic decrease with the increasing radial distance in the spherical microgel particles. This structure led to the formation of more loose gel structure on the particle surface with respect to the center. Then the use of hydrophilic crosslinking agents in the dispersion polymerization of NIPA made possible the synthesis of thermosensitive microgels carrying long, flexible and chemically derivatizable (i.e., hydroxyl functionalized) fringes on the surface by a single-stage dispersion polymerization. The microgels with all crosslinking agents exhibited volume phase transition with the increasing temperature. The microgel obtained by the most hydrophilic crosslinking agent, GDMA exhibited higher hydrodynamic diameters in the fully swollen form at low temperatures than those obtained by PETA and PEPTA. Higher hydrodynamic size decrease from fully swollen form to the fully shrunken form was also observed with the same microgel.

Preparation of an ion-exchange chromatographic support by a "grafting from" strategy based on atom transfer radical polymerization.

A new "grafting from" strategy based on surface-initiated atom transfer radical polymerization (ATRP) was first used for the preparation of a polymer-based ion-exchange support for HPLC. The most important property of the proposed method is to be applicable for the synthesis of any type of ion exchanger in both the strong and the weak forms. Monodisperse, porous poly(glycidyl methacrylate-co-ethylene dimethacrylate), poly(GMA-co-EDM) particles 5.8 mum in size were synthesized by "modified seeded polymerization". Poly(dihydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(DHPM-co-EDM) particles were then obtained by the acidic hydrolysis of poly(GMA-co-EDM) particles. The ATRP initiator, 3-(2-bromoisobutyramido)propyl(triethoxy)silane was covalently attached onto poly(DHPM-co-EDM) particles via the reaction between triethoxysilane and diol groups. In the next stage, the selected monomer carrying strong cation exchanger groups, 3-sulfopropyl methacrylate (SPM), was polymerized on the initiator-immobilized particles via surface-initiated ATRP. The degree of polymerization of SPM (i.e., length of polyionic ligand) on the particles was precisely controlled by adjusting ATRP conditions. Poly(SPM)-grafted poly(DHPM-co-EDM) particles obtained with different ATRP formulations were tried as chromatographic packing in the separation of proteins by ion-exchange chromatography. The proteins were successfully separated with higher column yields with respect to the previously proposed materials. The plate heights between 100 and 150 mum were achieved with the column packed with the particles carrying the shortest poly(SPM) chains. The plate height showed no significant increase with increasing flow rate in the range of 0.5-16 cm/min.

Monodisperse porous poly(vinyl acetate-co-divinylbenzene) particles by single-stage seeded polymerization: a packing material for reversed phase HPLC.

A single-stage swelling and polymerization method was proposed for the synthesis of monodisperse porous poly(vinyl acetate-co-divinylbenzene) [poly(VAc-co-DVB)] particles with different VAc/DVB feed ratios. The particles obtained with the VAc/DVB feed ratio of 50:50 v/v had a narrow pore size distribution exhibiting a sharp peak at 30 nm. Based on this distribution the mean pore size and the specific volume were determined as 12 nm and 1.39 mL/g, respectively. The specific surface area of poly(VAc-co-DVB) particles was found to be 470 m2/g. These properties make poly(VAc-co-DVB) particles a promising support for potential HPLC applications. Poly(vinyl alcohol-co-divinylbenzene) [poly(VA-co-DVB)] particles were then obtained by the basic hydrolysis of poly(VAc-co-DVB) particles. The hydroxyl groups on poly(VA-co-DVB) particles have a suitably reactive functionality for surface grafting or derivatization protocols aiming at synthesizing various HPLC packings. The examination of poly(VA-co-DVB) particles by confocal laser scanning microscopy showed the homogeneous distribution of hydroxyl functionality in the particle interior. As a starting point, the chromatographic performance of plain material, poly(VAc-co-DVB) particles produced with VAc/DVB feed ratio of 50:50 (v/v) was tested by a commonly utilized chromatographic mode, reversed phase chromatography. Poly(VAc-co-DVB) particles were successfully used as packing material in the RP separation of alkylbenzenes with resolutions higher than 1.5. Theoretical plate numbers up to 17 500 plates/m were achieved. No significant change both in the chromatographic resolution and column efficiency was observed with increasing flow rate. The chromatography showed that poly(VAc-co-DVB) particles were a suitable starting material for the synthesis of chromatographic packings for different modes of HPLC.

Monodisperse porous polymer particles with polyionic ligands for ion exchange separation of proteins.

A new "grafting to" strategy was proposed for the preparation of polymer based ion exchange supports carrying polymeric ligands in the form of weak or strong ion exchangers. Monodisperse porous poly(glycidyl methacrylate-co-ethylene dimethacrylate), poly(GMA-co-EDM) particles 5.9 microm in size were synthesized by "modified seeded polymerization". Poly(2,3-dihydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(DHPM-co-EDM) particles were then obtained by the acidic hydrolysis of poly(GMA-co-EDM) particles. The hydroxyl functionalized beads were treated with 3-(trimethoxysilyl)propyl methacrylate to have covalently linked methacrylate groups on the particle surface. The selected monomers carrying weak or strong ionizable groups (2-acrylamido-2-methyl-1-propane sulfonic acid, AMPS; 2-dimethylaminoethylmethacrylate, DMAEM and N-[3-(dimethylamino)propyl] methacrylamide, DMAPM) were subsequently grafted onto the particles via immobilized methacrylate groups. The final polymer based materials with polyionic ligands were tried as chromatographic packing in the separation of proteins by ion exchange chromatography. The proteins were successfully separated both in the anion and cation exchange mode with higher column yields with respect to the previously proposed materials. The plate heights obtained for poly(AMPS) and poly(DMAEM) grafted poly(DHPM-co-EDM) particles by using proteins as the analytes were 80 and 200 microm, respectively. Additionally, the plate height exhibited no significant increase with the increasing linear flow rate in the range of 1-20 cm/min. The most important property of the proposed strategy is to be applicable for the synthesis of any type of ion exchanger both in the strong and weak form.

A new affinity-HPLC packing for protein separation: Cibacron blue attached uniform porous poly(HEMA-co-EDM) beads.

In this study, a new affinity high-performance liquid chromatography (HPLC) stationary phase suitable for protein separation was synthesized. In the first stage of the synthesis, uniform porous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate), poly(HEMA-co-EDM), beads 6.2 mum in size were obtained. Homogeneous distribution of hydroxyl groups in the bead interior was confirmed by confocal laser scanning microscopy. The plain poly(HEMA-co-EDM) particles gave very low non-specific protein adsorption with albumin. The selected dye ligand Cibacron blue F3G-A (CB F3G-A) was covalently linked onto the beads via hydroxyl groups. In the batch experiments, albumin adsorption up to 60 mg BSA/g particles was obtained with the CB F3G-A carrying poly(HEMA-co-EDM) beads. The affinity-HPLC of selected proteins (albumin and lysozyme) was investigated in a 25 mm x 4.0-mm inner diameter column packed with CB F3G-A carrying beads and both proteins were successfully resolved. By a single injection, 200 mug of protein was loaded and quantitatively eluted from the column. The protein recovery increased with increasing flow rate and salt concentration of the elution buffer and decreased with the increasing protein feed concentration. During the albumin elution, theoretical plate numbers up to 30,000 plates/m were achieved by increasing the salt concentration.

Formation of the cochlear nerve in the modiolus of the guinea pig and human cochleae.

BACKGROUND: Central processes of the bipolar neurons in the spiral ganglion converge in the modiolus to form the initial portion of the auditory branch (cochlear nerve) of the eighth cranial nerve. This occurs before the cochlear nerve passes through the internal auditory meatus. The neurons of the spiral ganglion send their central processes towards the internal acoustic meatus, through a single canal to form the cochlear nerve. These processes are described in many textbooks as running through numerous longitudinal small canals called canales longitudinales modioli before entering the internal acoustic meatus. Results of this study indicated that the term; "canalis longitudinalis modioli" was considered to be more appropriate than the former. METHODS: Central processes of the bipolar neurons in the spiral ganglion of the guinea pig and human cochleae were investigated using stereo, light and electron microscopy. RESULTS: Detailed examination of the guinea pig and human cochleae by light, electron and stereomicroscopy did not reveal multiple longitudinal canals but a single canal for the cochlear nerve. CONCLUSIONS: The singular term canalis longitudinalis modioli is more appropriate than canales longitudinales modioli.

The protective effect of melatonin on adriamycin-induced acute cardiac injury.

BACKGROUND: Cardiotoxicity is the main complication of adriamycin (ADR), which is a widely used chemotherapeutic agent. OBJECTIVE: To examine the potential cardioprotective effect of melatonin (MEL) on acute ADR cardiotoxicity in a rat model. METHODS: Cardioprotection was assessed on the basis of myocardial lipid peroxidation and ultrastructure. Rats were given MEL at a daily dose of 5 mg/kg and ADR 15 mg/kg, intraperitoneally. The MEL-1 group rats received one dose and the MEL-7 group rats six daily doses of MEL and were sacrificed at the end of one and seven days, respectively. Rats in the ADR-1 and ADR-7 groups were each given a single dose of ADR, and were then sacrificed 24 h and seven days later, respectively. The MEL+ADR-1 group rats received one dose each of ADR and MEL simultaneously and were sacrificed 24 h later. The MEL+ADR-7 group received a single dose of ADR plus a daily MEL dose for six consecutive days, and were sacrificed seven days after the ADR injection. RESULTS: Lipid peroxidation products were elevated in both ADR-1 and ADR-7 groups, and this elevation was significantly inhibited by MEL treatment. Electron microscopy confirmed that ADR was positively cardiotoxic after one and seven days of exposure. The extent of ADR-induced myocardial damage was markedly reduced when MEL was combined with ADR (MEL+ADR-1 and MEL+ADR-7). CONCLUSION: The results suggest that MEL is highly efficacious at reducing the acute cardiotoxic effects of high dose ADR, and that it acts by preventing lipid peroxidation.

Comparison of thicknesses of the myocardial fibers of anencephalic and normal human fetuses.

When heart transplantation is needed in newborns, brain death should be confirmed, and the heart should not be exposed to hypoxia. The anencephalic newborn has been presented as a donor in heart transplantation. It is important, therefore, to evaluate possible morphological differences in the hearts of anencephalic cases. In this study, muscle fibers were studied in 10 anencephalic and 10 normal fetuses (27-35 weeks) and the results were compared. Random samples were taken from the upper 1/3 of the right ventricle's posterior wall and processed for light microscopic examination. Thicknesses of the 100 myocardial muscle fibers for each fetus were evaluated. There was statistically no significant difference between the anencephalic and normal fetus groups and the sex groups. Morphological features of the transplant probably affects the performance of the heart after operation. The anencephalic fetuses could be unique donors for heart transplantation.

Antioxidant actions and early ultrastructural findings of thiopental and propofol in experimental spinal cord injury.

Thiopental and propofol are effective antioxidant agents. The current study was undertaken to examine the neuroprotective effects of a single intraperitoneal dose of thiopental and propofol. Effects of the drugs were evaluated by lipid peroxidation and ultrastructural findings. Fifty male Wistar rats were divided into five groups. Group 1 was the control group. Rats underwent laminectomy only, and nontraumatized spinal cord samples were obtained 1 hour after surgical intervention. All other rats sustained a 50-g/cm contusion injury by the weight drop technique. Group 2 rats underwent spinal cord injury alone, group 3 rats received 1 mL intralipid solution intraperitoneally immediately after trauma as the vehicle group, group 4 rats received a 15-mg/kg single dose of thiopental, and group 5 rats received a 40-mg/kg single dose of propofol intraperitoneally following the trauma. Samples from groups 2, 3, 4, and 5 were obtained 1 hour after injury. Lipid peroxidation was determined by measuring the concentration of malondialdehyde in the spinal cord tissue. The ultrastructure of the spinal cord was determined by electron microscopy. The contusion injury was associated with a rise in lipid peroxidation. Compared with the trauma group there was significant attenuation in lipid peroxidation of groups 4 and 5. Ultrastructural findings showed that the rats of group 4 sustained minor damage after spinal cord injury, but there was more evident damage in group 5 rats. These results indicate that thiopental decreases lipid peroxidation and improves ultrastructure, whereas propofol decreases lipid peroxidation without improving ultrastructure 1 hour after spinal cord injury in rats.