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At least 1,261 records · Page 70Linked to original sources
PubMed1984

Radioimmunoassay of met-enkephalin in microdissected areas of paraformaldehyde-fixed rat brain.

We studied the effect of various sample preparation procedures on rat brain met-enkephalin content, measured by radioimmunoassay. Whole brain met-enkephalin content of rats killed by decapitation followed by immediate tissue freezing was similar to that of rats killed by microwave irradiation and to those of rats anesthetized with pentobarbital or halothane before killing, whether previously perfused with paraformaldehyde or not. In contrast, a decrease (up to 80%) in met-enkephalin concentrations was observed when brain samples were frozen and thawed to mimic the procedure utilized in the "punch" technique for analysis of discrete brain nuclei. This decrease was totally prevented by paraformaldehyde perfusion of the brain prior to sacrifice. Brain perfusion did not alter the amount of immunoassayable met-enkephalin extracted from tissue or its profile after Sephadex chromatography. Paraformaldehyde perfusion results in better morphological tissue preservation and facilitates the "punch" dissecting technique. Paraformaldehyde perfusion may be the procedure of choice for the measurement of neuropeptides in specific brain nuclei dissected by the "punch" technique.

Anesthesia↗
PubMed1993

Anatomy of cavernous nerves distal to prostate: microdissection study in adult male cadavers.

Retrograde and antegrade dissections from the penile hilum to the prostatic area and the glans penis were performed in 4 formalin-preserved adult male cadavers. In addition to the medial branches accompanying the urethra, the lateral branches of the cavernous nerves pierced the urogenital diaphragm 4 to 7 mm from the striated muscles of the external sphincter. At the penile region, multiple communications between the cavernous and dorsal nerves were noted that suggest that either the cavernous nerves use the dorsal nerve as a carrier to the distal portion of the penis or the dorsal nerve may itself contain autonomic fibers. These findings will improve our ability to preserve erectile function during pelvic, urethral, and penile surgery.

Adult↗
PubMedDate not supplied

Scanning electron microscopy of primate chorionic villi following ultrasonic microdissection.

Villi from human, macaque and baboon placentae were subjected to ultrasonication after prolonged osmication, and examined by scanning electron microscopy. The technique was often successful in removing the overlying trophoblast and revealing expanses of the trophoblastic basal lamina, a conclusion corroborated by transmission electron microscopy. These preparations bore a remarkable similarity in appearance to microvascular cast preparations of the fetal vasculature. Relatively straight parallel tubules appeared to correspond in position to the location of fetal vessels in intermediate villi, whereas portions of the basal laminae of terminal villi were in the form of convoluted, branched cylinders similar to SEM images of fetal capillaries of terminal villi. The basal lamina did not have evidence of pores as has been described in some basal laminae.

Animals↗
PubMed1989

Comprehensive polypeptide analysis of microdissected rat brain areas: combining 2-dimensional gel electrophoresis with 2-dimensional HPLC and immunoanalysis and sequencing procedures.

An improved methodology has been developed which allows resolution, identification, and quantitation of hundreds of proteins and neuropeptides from a single rat brain nucleus (5 mg wet wt.). After metabolic labelling, proteins (greater than about 15 kDa) are separated from peptides (less than about 10 kDa) by sonicating the tissue in an acidic peptide extraction buffer; after centrifugation, proteins are in the pellet, peptides in the supernatant. To quantitate peptide synthesis, peptides are resolved to purity by reverse-phase HPLC followed by ion exchange HPLC. Proteins are resolved with a two-dimensional (2-D) gel protocol optimized for neural tissue. To identify specific proteins by immunoanalysis, proteins are transferred to polyvinyl difluoride (Immobilon) and immunostained in the presence of Tween blocking buffer. After visualization with an avidin-biotin alkaline phosphatase procedure, the blot is post-stained with India ink to visualize the protein pattern context. To sequence spots, proteins are transferred to Immobilon, stained with Coomassie, and directly subjected to automated gas phase sequencing. The immunoblot procedure can detect less than 0.1 pmol protein, and the sequencing procedure can detect less than 10 pmol protein. After transfer enough material remains on the gels to allow subsequent autoradiography or silver stain. Quantitative analysis of 2-D gels is examined in a companion paper. These procedures should enhance the utility of 2-D gels in neurochemical studies.

Amino Acid Sequence↗
PubMed1986

Neuronal influence on antigenic marker profile, cell shape and proliferation of cultured astrocytes obtained by microdissection of distinct layers from the early postnatal mouse cerebellum.

To study the cellular heterogeneity of astrocytes from early postnatal mouse cerebellum in culture, Bergmann glia were enriched by hand-dissection of Purkinje, molecular and external granular layers ('outer' layer) and fibrous astrocytes of white matter and deep cerebellar nuclei ('inner' layer). Both populations of GFA protein and vimentin-positive astrocytes express N-CAM and the L2/HNK-1 epitope, but not tetanus toxin receptors or A2B5 antigen, at levels detectable by indirect immunofluorescence procedures. The two astrocyte populations are thus indistinguishable from each other. Expression of tetanus toxin receptors and A2B5 antigen in these astrocytes can, however, be induced by removal of neurons. The expression of tetanus toxin receptors is again reduced by readdition of purified populations of small cerebellar neurons. Morphology and proliferation of astrocytes from both layers is also dependent on the presence of neurons: removal of neurons leads to an epithelioid, rather than star-shaped morphology and a severalfold increase in proliferation. Readdition of neurons induces astrocytes to return to their star-shaped morphology. Epidermal growth factor increases proliferation in both populations of astrocytes. We conclude that neither antigenic marker profile, morphology nor proliferative responses serve to distinguish between enriched Bergmann glia and enriched fibrous astrocytes.

Animals↗
PubMed1994

Gonadotropin-releasing hormones in microdissected brain regions of an amphibian: concentration and anatomical distribution of immunoreactive mammalian GnRH and chicken GnRH II.

Mammalian and chicken II gonadotropin-releasing hormones (mGnRH, cGnRH II) were extracted from 350 microns diameter punches from brains of a urodele amphibian, Taricha granulosa, and measured by means of radioimmunoassay (RIA) with specific antisera. Measurable quantities of both peptides were found in the lateral pallium, the subpallium (along the course of the nervus terminalis), the preoptic area, habenula, optic tectum, infundibulum, paraventricular organ/posterior tubercle of the caudal diencephalon, medulla, and cerebrospinal fluid. Highest concentrations of both peptides were in the preoptic area and infundibulum, suggesting a role in gonadotropin release. In most extrahypothalamic regions, cGnRH II concentrations exceeded those of mGnRH, suggesting that cGnRH II may function as a neurotransmitter in many sites, perhaps to control reproductive behaviors. Results are largely consistent with immunocytochemical (ICC) analyses, except that RIA revealed small amounts of both peptides not found by ICC in some areas of the brain. Results from this microdissection/RIA study and prior ICC studies in amphibians support the conclusions that GnRH cell bodies in the terminal nerve and preoptic area, which project mainly to the median eminence and habenula, express mGnRH, and that GnRH cell bodies in the caudal diencephalon, which project widely throughout the CNS, express cGnRH II. Comparative data support the view that cGnRH II, and the neural systems in which it is expressed, evolved early in vertebrate phylogeny and have been highly conserved.

Animals↗
PubMed1989

Biochemical evidence for the GABA regulation of vasopressin levels in microdissected brain structures after servo-controlled hypotension.

Discrete brain structures were analysed for gamma-aminobutyric acid (GABA) and vasopressin content in normo- and hypotensive rats treated with the glutamic acid decarboxylase inhibitor, 3-mercaptopropionic acid (MPA) and the GABAA agonist muscimol. In the normotensive group treated with MPA only, the concentration of vasopressin increased in the supraoptic nucleus, indicating an inhibitory role for GABA. In the hypotensive group a rise in the vasopressin level in the nucleus of the solitary tract was detected and the GABA level decreased in the supraoptic nucleus. Muscimol decreased the concentration of vasopressin in the nucleus of the solitary tract. The changes in the concentration of vasopressin may be a result of increased or decreased activation of the GABAergic system. The results show that the GABA- and vasopressinergic systems somehow interact although the more precise way of action remains to be clarified.

3-Mercaptopropionic Acid↗