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At least 73 records · Page 4Linked to original sources
PubMed1979

Prostaglandin E1 raises the cAMP content of peripheral nerve tissue.

Prostaglandins of the E type have been found to increase the cAMP content in peripheral nerve tissue of several species. In rabbit vagus nerve, for example, the effect is rapid (1--5 min), it can be elicited by 10(-6) M PGE1 and it is maximal at 10(-5) M. In this preparation the increase of the cAMP content caused by PGE1 is about 4-fold, whereas it is about 2-fold in the vagus of calf. PGE1 also causes an increase in cAMP level in the superior cervical ganglion of calf, rat and rabbit. In these tissues, however, the presence of a phosphodiesterase inhibitor is required for cAMP accumulation.

Animals↗
PubMedDate not supplied

[Protein synthesis in cerebral cortex cells of rats exposed to hypoxia during interparenchymal administration of protein isolated from embryonal nerve tissue into the cerebral cortex].

The stage-specific activator protein CF was studied for effects on protein biosynthesis in the fractions rich in nerve and glial cells of the brain cortex of rats which had been exposed to hypoxia. Protein was isolated from the cortex of embryos or from the cerebellum of 8-10-day rats, the period being of the most active nerve cell proliferation. Following 4 days of the interparenchymal administration of SF into the cerebral cortex of the animals exposed to hypoxia there was an increase in the rate of 3-H-leucine incorporation into the nerve cells up to the values observed in the neurons of the cerebral cortex of intact animals. The level of protein synthesis in the glial cells remained unchanged. There were no increases in protein synthesis either in nerve or glial cells 120 days after single administration of SF. The findings were compared with the experimental evidence for the biosynthesis of macromolecules in various cerebral cortical cells from rats exposed to hypoxia and undergone transplantation of embryonal nerve tissue.

Animals↗
PubMed2006

Peripheral nerve tissue engineering: autologous Schwann cells vs. transdifferentiated mesenchymal stem cells.

Mesenchymal stem cells (MSCs) were evaluated as an alternative source for tissue engineering of peripheral nerves. MSCs, transdifferentiated MSCs, or Schwann cells cultured from male rats were grafted into devitalized autologous muscle conduits bridging a 2-cm sciatic nerve gap in female rats. The differentiation potential of MSCs and transformed cultivated MSCs into Schwann cell-like cells was exploited using a cocktail of cytokines. Polymerase chain reaction of the SRY gene confirmed the presence of the implanted cells in the grafts. After 6 weeks, regeneration was monitored clinically, histologically, and morphometrically. Autologous nerves and cell-free muscle grafts were used as control. Revascularization studies suggested that transdifferentiated MSCs, in contrast to undifferentiated MSCs, facilitated neo-angiogenesis and did not influence macrophage recruitment. Autologous nerve grafts demonstrated the best results in all regenerative parameters. An appropriate regeneration was noted in the Schwann cell-groups and, albeit with restrictions, in the transdifferentiated MSC groups, whereas regeneration in the MSC group and in the cell-free group was impaired. The results indicate that transdifferentiated MSCs implanted into devitalized muscle grafts are able to support peripheral nerve regeneration to some extent, and offer a potential for new therapeutic strategies.

Animals↗
PubMed2005

Quantitative determination of endogenous sorbitol and fructose in human nerve tissues by atmospheric-pressure chemical ionization liquid chromatography/tandem mass spectrometry.

Attachment of anions to sorbitol and fructose has been shown to enhance sensitivity in both electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI) mass spectrometry. The post-column addition of CHCl3 produced Cl-adducts of sorbitol and fructose but their signals were suppressed due to the elevated background. Different chlorinated compounds and different additive methods were systematically investigated to form more abundant Cl-adduct precursor ions and deprotonated product ions. The major causes of the high background were explored and effective methods were developed to improve the signal-to-noise ratios and reproducibility. The compositions of mobile phase, percentages of organic modifiers (MeCN, MeOH and water), columns, oven temperature, flow rates and different gradients were investigated to separate sorbitol from fructose along with their isomers including glucose, galactose, mannose, sorbose, mannitol, and dulcitol. The optimized separation was achieved on a Luna 5 mu NH2 100A column (150 x 4.6 mm) using a mobile phase containing MeCN with 0.1% of CH2Cl2 and 50% MeOH in water at a flow rate of 800 microL/min and an oven temperature of 40 degrees C using a gradient liquid chromatography (LC) system. Human nerve tissue samples were extracted by protein precipitation followed by mixed-mode solid-phase extraction. The LC/ESI-MS/MS method produced higher peak intensities than LC/APCI-MS/MS. However, there were matrix effects from extracted tissues in LC/ESI-MS/MS but not in LC/APCI-MS/MS. Consequently, APCI proved to be the more effective method of ionization. Then the LC/APCI-MS/MS method was fully validated and successfully applied to analysis of clinical samples. The concentrations of endogenous sorbitol and fructose were determined using calibration curves employing sorbitol-13C6 and fructose-13C6 as surrogate analytes. The method has provided excellent intra- and inter-assay precision and accuracy with linear ranges of 0.2-80 ng/mg for sorbitol and 1-400 ng/mg for fructose in human nerve tissues.

Atmospheric Pressure↗
PubMed1988

Development and advantages of serum-free, chemically defined nutrient media for culturing of nerve tissue.

This paper describes in a historical perspective the development of serum-free nutrient media suitable for long-term culturing of nerve tissue. Several disadvantages of the use of serum are discussed, coupled with an acknowledgement that it is not always advisable to replace a routinely used serum-supplemented medium by a chemically defined medium with the expectation of immediate success. Therefore a strategy is given on how to develop a chemically defined medium that is thoroughly tuned to the specific needs of the cell type to be cultured. It is argued that such a medium has several substantial advantages over the use of serum.

Animals↗
PubMed2003

Can ultrasound be used to stimulate nerve tissue?

BACKGROUND: The stimulation of nerve or cortical tissue by magnetic induction is a relatively new tool for the non-invasive study of the brain and nervous system. Transcranial magnetic stimulation (TMS), for example, has been used for the functional mapping of the motor cortex and may have potential for treating a variety of brain disorders. METHODS AND RESULTS: A new method of stimulating active tissue is proposed by propagating ultrasound in the presence of a magnetic field. Since tissue is conductive, particle motion created by an ultrasonic wave will induce an electric current density generated by Lorentz forces. An analytical derivation is given for the electric field distribution induced by a collimated ultrasonic beam. An example shows that peak electric fields of up to 8 V/m appear to be achievable at the upper range of diagnostic intensities. This field strength is about an order of magnitude lower than fields typically associated with TMS; however, the electric field gradients induced by ultrasound can be quite high (about 60 kV/m2 at 4 MHz), which theoretically play a more important role in activation than the field magnitude. The latter value is comparable to TMS-induced gradients. CONCLUSION: The proposed method could be used to locally stimulate active tissue by inducing an electric field in regions where the ultrasound is focused. Potential advantages of this method compared to TMS is that stimulation of cortical tissue could be highly localized as well as achieved at greater depths in the brain than is currently possible with TMS.

Electric Stimulation↗
PubMed1984

Plasma exchange in patients with Guillain-Barré syndrome: clinical improvement in patients with serum IgG antibodies to peripheral nerve tissue.

The mixed hemagglutination technique was used to demonstrate IgG antibodies to peripheral nerve tissue in sera from patients with Guillain-Barré syndrome. The clinical effect and the effect on the antibodies of plasma exchange (PE) were examined in 24 patients, 16 patients with acute form and 8 patients with the chronic form of the disease. Neurological examination with muscle testing and neurophysiological examination of the patients were performed before and immediately after the PE. Before PE antibodies were detected in sera from 15 of the patients. These patients showed clinical improvement during the treatment, however in one of the patients only after a time interval of 2 weeks. After PE, antibodies were detected in sera from only 3 of the patients. The 9 patients without detectable antibodies showed no clinical improvement.

Adolescent↗
PubMed1991

Effects of the penetration of a root canal filling material into the mandibular canal. 2. Changes in the alveolar nerve tissue.

The root canal filling material "Vitapex" (Neo Dental Chemical Products Co., Tokyo), made of calcium hydroxide and iodoform with the addition of silicone oil, was experimentally injected into the mandibular canals of dogs, and its effect on the alveolar nerve tissue was examined by light and electron microscopy. No change was observed as long as the injected paste did not come into direct contact with the nerve, but tissue damage was found at sites of direct contact. After removal of degenerated nerve debris by macrophages and Schwann cells, the persisting external membranes or "Schwann tubes" appeared to provide a scaffolding for axonal regeneration and Schwann cell proliferation.

Animals↗
PubMedDate not supplied

[Novel carboxypeptidase for processing of animal nerve tissue enkephalins].

New carboxypeptidase which catalyzes the C-terminal arginine splitting from hexapeptide (an enkephalin precursor) Tyr-Gly-Gly-Phe-Met-Arg is revealed in the cat nerve tissue. The enzyme is activated by cobalt ions, the pH action optimum being 7.6. A relatively high activity of carboxypeptidase in the hypothalamus, midbrain and medulla oblongata permits supposing that it is the key enzyme of the enkephalin processing in areas of the limbic brain system.

Animals↗
PubMed1969

Some effects of PCO2 and pH on nerve tissue.

1. Rat phrenic nerve preparations were used in vitro to study action potential amplitude and nerve conduction time under varying conditions of Pco(2) and sodium bicarbonate concentration in the surrounding Krebs solution.2. A correlation was found between action potential amplitude and pH but not between action potential amplitude and Pco(2).3. A better correlation was found between conduction time and pH than between conduction time and Pco(2).

Action Potentials↗