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Biomedical subjects

G Tapia-Arizmendi

Publications and source records attributed to G Tapia-Arizmendi.

At least 19 recordsLinked to original sources
PubMed1992

Golgi method without osmium tetroxide for the study of the central nervous system.

A variant Golgi technique was developed that consisted of substituting osmium tetroxide with formaldehyde as the initial fixative in intracardiac perfusion, along with the addition of glacial acetic acid to the chromating fluid. This procedure avoids disposal of dangerous waste substances into the environment. Other advantages include 1) reduction of cost, danger to lab workers, and risk of disruption of the tissue slices during their handling by eliminating the osmium tetroxide, 2) clear tissue background, 3) greater quantity of impregnated neurons than in the classical procedure, with distinct morphological details easily identified even in gross sections and 4) reduction in processing time.

Animals↗
PubMed1991

Effect of 3-acetylpyridine on serotonin uptake and release from rat cerebellar slices.

The cerebellum receives indolaminergic fibers influencing Purkinje cell discharges. Data from our laboratories have demonstrated an endogenous release of serotonin (5-HT) and a Na(+)-dependent uptake and Ca(2+)-dependent release of [3H]5-HT from slices, homogenates and synaptosomal fractions of the rat cerebellar molecular layer. While the neurotransmitter produced by climbing fibers has been sought for in several studies and some of the classical transmitters have been ruled out, as yet this neurotransmitter is unknown. The aim of this work was to measure the 5-HT uptake and release from rat cerebellar slices, 6 h and 15 days after intraperitoneal injection of 3-acetylpyridine (3-AP) (75 mg/kg), harmaline (15 mg/kg) and nicotinamide (300 mg/kg). A histological study of medulla and cerebellar cortex in these animals showed destruction of neurons in the inferior olivary nuclei and changes in the granulation of the cortical molecular layer in the cerebellum. A significant reduction of the 5-HT content (100%), 5-HT uptake (60%) and its Vmax (60%) was seen on the 5th day, in cerebellar preparations obtained from rats injected with 3-AP. The Ca(2+)-dependent release of 5-HT from these preparations was found to be similar to the basal values, in spite of depolarizing stimuli with 53 mM KCl or veratrine (60 micrograms/ml). The results suggest that 5-HT could play an important role as neurotransmitter produced by some climbing fibers.

Animals↗
PubMed1988

Ultrastructural alterations in caudate nucleus, cerebral cortex and hippocampus produced by morphine.

1. Chronic morphine administration to rats produced diverse ultrastructural alterations in nerve cells and neuropile of caudate nucleus, cerebral cortex and hippocampus through a short term abstinence period. 2. All areas studied showed increasing damage related to time elapsed between the last morphine injection and animal sacrifice. 3. Intracytoplasmic neuronal membranous organelles mainly suffered severe swelling, membrane disarrangement and eventually cell disruption in all areas studied. 4. Hippocampus was the most affected area throughout the study, followed by caudate nucleus and cerebral cortex, where focal damage was seen. 5. Susceptibility to morphine cytotoxic effect in the three areas studied appears to be unrelated to their opiate receptor density. 6. Mitochondrial alterations produced by morphine could be related to interference of the intracellular energy production system and consequent unrestricted cell membrane permeability to water and solutes.

Animals↗
PubMed1987

Structural changes in caudate nucleus, cerebral cortex and hippocampus induced by morphine. Light microscopy study.

Intraperitoneal chronic morphine administration to rats produced structural alterations in nerve cells of caudate nucleus, cerebral cortex and hippocampus. All areas studied showed increased alterations related to time elapsed between last morphine injection and fixation of tissue samples. Lesions mainly consisted in vacuolar degeneration of nerve cells. The most extense and intense lesions were observed in hippocampus. Sensorimotor cortex and caudate nucleus showed focal damage. Neurocytotoxic effect of morphine appears to be unrelated to the opiate receptor density in brain areas, and the brain regions susceptible to that effect appears to be different from brain areas related to adaptation to morphine. Effect of morphine on integrity and function of nerve cells mitochondria, interfering with energy production could play an important role in the pathogenesis of neuronal lesions.

Animals↗
PubMed1987

A distinct congenital motor and sensory neuropathy (neuronal type) with dysmorphic features in a father and two sons. A variant of Charcot-Marie-Tooth disease.

A 37-year-old male had clinical and electrophysiological features of hereditary motor and sensory neuropathy (neuronal type) with onset in infancy, as well as histological picture of neurogenic myopathy. Two sons, aged 2 and 3 4/12 years, showed congenital contraction deformities of feet, delayed motor development, and electrophysiological features similar to those of the father. All three also presented laryngeal abnormalities, peculiar facies, short neck, narrow shoulders and protruding chest. The authors conclude that this aggregate of anomalies constitutes a "new" syndrome probably due to an autosomal dominant gene.

Abnormalities, Multiple↗
PubMed1986

Ehlers-Danlos features with progeroid facies and mild mental retardation. Further delineation of the syndrome.

A syndrome characterized by progeroid facies, multiple nevi, mild mental retardation, skin hyperextensibility, bruisability, moderate skin fragility, joint hypermobility principally in digits, is described in two unrelated patients. Electron microscopy of the skin showed some fragmentation of the elastic fibers' portion and moderate electrodensity in the amorphous portion. Since a practically identical constellation of clinical features was previously reported in three patients, the individualization of a distinct connective tissue disorder, probably autosomal dominant, with variable expressivity is concluded.

Adolescent↗
PubMed1980

Study of the trophozoite surface of Entamoeba histolytica with high resolution cytochemical studies and scanning electron microscopy.

A study of positive and negative electrical surface charges of Entamoeba histolytica trophozoites axenically cultured was carried out by means of incubation with colloidal iron solutions at pH 4.0 and 1.8, respectively. The samples were examined under the transmission electron microscope. Human erythrocytes were studied using the same experimental conditions as controls. In these cells the surface negative charges were homogeneously distributed on the surface, whereas the positive charges were observed as irregularly distributed patches. No electrical charges were labelled into the trophozoite surface with the colloidal iron solutions employed. It can be correlated with previous biochemical and cytochemical studies, as well as with experimental data obtained by other authors. Likewise surface configuration was studied using the scanning electron microscope in three pathogenic strains of E. histolytica cultured in axemic or monoxenic conditions. A detailed description of the trophozoite surface configuration was made and findings were correlated with data obtained from transmission electron microscopy studies of the parasite. There were no differences in the trophozoite surface structure which could be related to the strains of E. histolytica examined or to the culture conditions employed.

Animals↗
PubMed1980

Ultrastructural changes induced by 3-acetylpyridine in the central nervous system of adult rats.

Intraperitoneal administration of an antimetabolite of nicotinamide, 3-acetylpyridine (3-AP) to adult rats at the dose of 65 mg/kg selectively produces lesions of the olivary nerve cells in the medulla oblongata. The neurons show progressive swelling and destruction with cell retraction, apparently by interference of energy production by means of formation of nicotinamide adenin dinucleotide analogues. Although the selectiveness of injury of olivary nerve cells to the action of 3-AP still remains unclear, the findings in the present work along with those reported in the literature reflect the existence of a regional characteristic pattern of metabolism in the various structures of the central nervous system.

Animals↗
PubMed1980

Further studies on the blood-brain barrier to low molecular weight substances. An ultrastructural cytochemical study.

A high resolution cytochemical study was performed in cats to investigate the cerebral blood vessel permeability to low molecular weight non-liposoluble substances. Sodium ferrocyanide was injected to four adult cats through an intraventricular canula and a copper solution was perfused intravascularly. Electroencephalographic recording throughout the experiments showed no detectable alterations induced by the administered solutions. Brain fragments fixed by intravascular perfusion were processed for electron microscopy. Pineal gland from the same animals and masseter muscle fragments in which ferrocyanide had been directly injected in those animals were studied as controls. A copper ferrocyanide suspension was directly injected into the lateral ventricle to two cats and 15 min later the brains were fixed by perfusion and processed for electron microscopy. An electrondense precipitate was seen in the interstitial and perivascular space, but not into the vessel lumen in these animals. No reaction product was observed in the brain parenchyma of cats injected intraventricularly with sodium ferrocyanide, whereas electron-dense deposits were clearly depicted in the pineal gland and masseter muscle in the same animals. The results further support the thesis that the junctions between the endothelial cells in brain capillaries represent a physical barrier to non-liposoluble substances.

Animals↗
PubMed1978

Proteolytic enzymes marking of malignant lymphoblasts, study of the L5178Y murine lymphoma.

The bovine pancreatic inhibitor of trypsin (trasylol, Bayer) (T) and the soy bean trypsin inhibitor (SBI) were coupled with peroxidase (P). With each one of these coupling products (T and P and SBI and P) the cell distribution of proteolytic enzymes (PE) of ascitic cells of L5178Y murine lymphoma, was localized. The reactions were developed by means of Karnowsky's reaction with diaminobenzidine and H2O2. The preparations were observed under light and electronic microscopy. It was found that L5178Y cells contain intracellular PE in granules measuring 0.1 to 0.8 min diameter, and superficial PE that form a continuous layer of 80 to 120 nm over the cell surface. Superficial PE were not identified in 20 per cent of L5178Y cells, while in every case intracellular granules were found. Both the macrophages and the polimorphonuclear cells present in the ascitic fluid contained intracellular PE granules measuring 0.05 to 0.4 micron in diameter, and did not contain superficial PE.

Animals↗
PubMed1978

Effects of the environmental light conditions on the ultrastructure of the harderian gland in the newborn rat. biochemical correlation with the pineal gland.

Morphological changes at the levels of both light and electron microscopy were studied regarding the secretory elements of the Harderian glands of neonatal rats, induced by environmental lighting conditions. The results were correlated with biochemical determinations of serotonin levels and hydroxyindole-O-methyl transferase (HIOMT) activity in the pineal gland. Neonatal male albino rats were divided into three groups: 12 were exposed to a light period for seven days; 12 to a dark period, and 12 to diurnal lighting conditions (light, 12 hours; darkness, 12 hours), as controls. In each group some animals were killed at 1.00 pm. The Harderian gland of each animal was immediately fixed and processed for light and electron microscopy while the pineal gland was homogenized in a fixative for biochemical determination of serotonin levels and HIOMT activity. On the light period the acinar lumen was observed to be dilated with increased secretions from the acini and excretory ducts while on the dark period the acinar lumen narrowed with hardly any secretions. On the dark period there were no changes in the cyclic variations of serotonin levels and HIOMT activity in the pineal gland; while on the light period, these cycles disappeared. It is concluded that secretory activity of the Harderian gland is modified by environmental lighting conditions, and that secretions produced by this gland appear to be directly related to the control mechanism of melatonin production by the pineal gland in neonatal rats.

Animals↗
PubMed1977

Qualitative x-ray spectrometric study of E. histolytica trophozoite nuclei.

Qualitative X-ray energy spectroscopical analysis was performed in two strains of Entamoeba histolytica trophozoites: HK-9; NIH strain, and HM-2; IMSS strain, cultured in axenic and monoxenic conditions, respectively. The trophozoites were fixed in buffered-glutaraldehyde, embedded in Epon, thick sectioned )50-200 nm), and mounted on nickel grids. X-ray emissions were analyzed with an Ortec X-ray energy detector and multichannel and analyzer adapted to a transmission electron microscope. The study was concentrated on the refractive intranuclear bodies, characteristically numerous in axenically grown E. histolytica trophozoites. Nuclei of trophozoites with those intranuclear bodies contained phosphorus, calcium, and magnesium in greater amounts than nuclei not containing those structures. This was true for all axenically grown trophozoites and two monoxenically grown trophozoites which contained four intranuclear bodies. It is concluded that the composition of the refractive intranuclear bodies in E. histolytica trophozites does not appear to change with the culture conditions or with the composition of the culture media.

Calcium↗
PubMed1976

[Antibodies in venereal sarcoma in dogs].

Neoplastic cell suspensions prepared from fourteen spontaneous and three transplanted vereal sarcomas of the dog were studied by microcytotoxicity and immunofluorescence tests. Serum and cell-surface antibodies were found in all cases. These antibodies were not capable of activating canine complement. Most likely these antibodies are not cytotoxic in vivo, but rather act by enhancing tumor growth.

Animals↗
PubMed1976

[Type A and C viruses particles in murine lymphoma L 5178Y].

The presence of virus particles and their possible mechanism of excretion was studied in cells of murine lymphoma L 5178Y grown intraperitoneally. Malignant cells obtained from 10 mice bearing this lymphoma were studied with the electron microscope. In 96% of the cells 1 to 30 viroid particles (VP) type C (VP-C) clumped or isolated, averaging six per cell were observed. Isolated VP-C were commonly seen within endoplasmic reticulum or budding off from cell surface. Such a finding was regarded as the mechanism of excretion. However, with the present findings it is not possible to draw any conclusions upon the oncogenic nature of the virus particles described herein.

Animals↗
PubMed1976

[A new technic for LE cell formation. Preliminary report].

In special designed vials using coverslides glued to segments of polyethilene test tubes of 0.15 ml of fibrin free blood were incubated during 45 min to 37 degrees C in a humid chamber. Blood samples were obtained from patients with disseminated Lupus erythematosus (DLE) and normal subjects (N). Adhered polymorpho-nuclear cells (PNC) to glass were washed with Hank's solution; immediately 0.15 ml of DLE or N serum containing 5X10(6) lymphocytes (L) were added to culture cells and incubated at 37 degrees C during 30 min. Lymphocytes were previously incubated at 37 degrees C during 30 min with either N serum or DLE serum. Thereafter the segment of polyethilene test tube was detached from coverslides and cells attached to glass was washed with Hank's solution and stained with Wright solution. PMN of DLE and N in presence of L of DLE and N incubated with fresh serum of DLE formed 5 to 15% of LE cells. Determining factor for LE cells formation is the serum of DLE. Slides contained only PMN and LE cells which make easy the observation of results. All possible combinations with PMN and DLE serum and N serum allowed inclusion of several negative or positive control groups.

Adolescent↗
PubMedDate not supplied

Qualitative X-ray spectrometric study to demonstrate ruthenium in central nervous system structures, after intraperitoneal injection of ruthenium red to adult rats.

A qualitative X-ray spectrometric study oriented to demonstrate ruthenium (Ru) in central nervous system was made after intraperitoneal (i.p.) injection of ruthenium red (RuR) to adult rats. Ru signals were depicted in the brain synaptosomal fraction since 60 min after RuR i.p. administration, corresponding to the latency period of the convulsive model injecting RuR systemically to adult rats. Ru signals were initially detected in pineal gland and periventricular regions, whereas X-rays from Ru atoms in cerebral cortex were detected at longer time intervals after RuR i.p. injection. It is concluded that RuR, a non-liposoluble substance, when injected systemically, passes from the blood stream to brain parenchyma, probably through areas without blood-brain barrier, reaching the neural elements related to the mechanisms of production of convulsions.

Animals↗
PubMedDate not supplied

Effects of ruthenium red intraperitoneally injected to adult rats, on the uptake and release of neurotransmitters from brain synaptosomes.

Effect of intraperitoneal (i.p.) injection of ruthenium red (RuR) to adults rats on catecholamine (CA) uptake and dopamine (DA) release was evaluated in brain synaptosomal fractions. No effect on CA uptake by synaptosomal fractions was seen when RuR was added in vitro. There was no effect of RuR injection i.p. to rats, on CA uptake by their brain synaptosomal fractions. A blocking effect on depolarizing induced released of DA from brain synaptosomal fraction obtained from rats previously injected i.p. with RuR was seen. A similar effect was observed on the basal DA efflux from synaptosomes loaded with (14C)DA obtained from rats i.p. injected with RuR. It is concluded that RuR, a non-liposoluble substance, when injected i.p. reaches the brain parenchyma through areas devoid of blood-brain barrier and interferes with Ca(++)-dependent release of neurotransmitters, inducing cerebral hyperexcitability and convulsions.

Animals↗