Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
1.
Vet Res Commun ; 47(4): 2259-2264, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37133705

RESUMO

In the ovine reproductive management, a thorough breeding soundness evaluation including specific inspection of the male genital tract represents a valuable tool for assessing the reproductive potential of a selected subject and for diagnosing genital disorders. During examination, accurate inspection on penis and prepuce is necessary, since conditions affecting these structures may hamper regular coitus. Records from 1270 males undergoing breeding soundness evaluation (n = 1232) or admitted for genital disorders to the Section of Obstetrics and Gynaecology (n = 38) of the Department of Veterinary Medicine, were collected, and lesions of penis and prepuce were therefore classified. The data collected revealed that 47/1270 rams examined presented lesions of the penis and prepuce. The most frequent condition was urolithiasis accounting for over 2% of the cases, followed by lack of the urethral process (0.39% incidence), lack of the glans penis and hypospadias (0.23% cases). Moreover, most of the conditions (40%) were observed in animals less than 2 years old, suggesting the importance of a careful breeding soundness evaluation in animals at young age.


Assuntos
Pênis , Uretra , Masculino , Ovinos , Animais , Estudos Retrospectivos , Reprodução , Carneiro Doméstico
2.
Electromagn Biol Med ; 36(1): 55-62, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27368079

RESUMO

Heretofore only observed in living systems, we report that weak-field ion cyclotron resonance (ICR) also occurs in inanimate matter. Weak magnetic field (50 nT) hydronium ICR at the field combination (7.84 Hz, 7.5 µT) markedly changes water structure, as evidenced by finding an altered index of refraction exactly at this combined field. This observation utilizes a novel technique which measures the scattering of a He-Ne laser beam as the sample is exposed to a ramped magnetic field frequency. In addition to the hydronium resonance, we find evidence of ICR coupling to a more massive structure, possibly a tetrahedral combination of three waters and a single hydronium ion. To check our observations, we extended this technique to D2O, successfully predicting the specific ICR charge-to-mass ratio for D3O+ that alters the index of refraction.


Assuntos
Ciclotrons , Oniocompostos/química , Refratometria/instrumentação , Água/química , Óxido de Deutério/química , Campos Magnéticos , Vibração
3.
Theriogenology ; 83(4): 687-92, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25476821

RESUMO

In vitro embryo production (IVP) and cryopreservation are associated with a high incidence of pregnancy complications and fetal abnormalities that may be linked with alterations of placental development. The amniotic fluid is partly derived from the transport of water and solutes across the placenta and provides the fetus with amino acids (AAs), which are the building blocks for biomolecules involved in physiological growth and development. To better understand the anomalies associated with IVP pregnancies, the present study was conducted to test the hypothesis that amniotic concentrations of AAs differ in pregnancies derived from vitrified/thawed (V/T) IVP embryos compared with gestations obtained with natural mating (NM) in sheep. Amniotic fluid was sampled in ewes that were pregnant after transfer of V/T IVP embryos and that had conceived with NM between Days 60 and 65 (V/T, n = 6; NM, n = 11) and between Days 80 and 85 (V/T, n = 5; NM, n = 14) of gestation via ultrasound-guided amniocentesis. Concentrations of 16 AAs in the amniotic fluid were measured using high-performance liquid chromatography. From Days 60 to 65 of gestation, concentrations of cystine, phenylalanine, and isoleucine were lower in V/T compared with NM ewes. From Days 80 to 85 of pregnancy, the mean concentrations of cystine and lysine were lower in the V/T versus NM groups. The total AA concentration per ewe was similar between the groups from Days 60 to 65 and 80 to 85 of gestation and decreased by 55% from Days 60 to 65 and 80 to 85 of gestation in all ewes. The most abundant AA from Days 60 to 65 of gestation was alanine in both groups, whereas from Days 80 to 85, the most abundant AAs were alanine in NM and glycine in V/T ewes; cystine was the less abundant detectable AA in all ewes at both stages of gestation. Results report that V/T IVP embryos have decreased concentrations of individual AAs in the amniotic fluid during the second trimester of gestation possibly because of an impaired placental vasculogenesis or because of a reduced placental transport. These novel findings are relevant to unravel the mechanisms responsible for the issues of pregnancies achieved with the transfer of IVP and cryopreserved embryos.


Assuntos
Líquido Amniótico/química , Transferência Embrionária/veterinária , Ovinos/fisiologia , Líquido Amniótico/metabolismo , Animais , Criopreservação/métodos , Criopreservação/veterinária , Feminino , Fertilização , Fertilização in vitro/veterinária , Gravidez
4.
Electromagn Biol Med ; 34(4): 370-5, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25020009

RESUMO

There is an ongoing question regarding the structure forming capabilities of water at ambient temperatures. To probe for different structures, we studied effects in pure water following magnetic field exposures corresponding to the ion cyclotron resonance of H3O(+). Included were measurements of conductivity and pH. We find that under ion cyclotron resonance (ICR) stimulation, water undergoes a transition to a form that is hydroxonium-like, with the subsequent emission of a transient 48.5 Hz magnetic signal, in the absence of any other measurable field. Our results indicate that hydronium resonance stimulation alters the structure of water, enhancing the concentration of EZ-water. These results are not only consistent with Del Giudice's model of electromagnetically coherent domains, but they can also be interpreted to show that these domains exist in quantized spin states.


Assuntos
Ciclotrons , Oniocompostos/química , Água/química , Campos Eletromagnéticos , Hidrogênio/química , Concentração de Íons de Hidrogênio , Íons , Temperatura , Fatores de Tempo , Vibração
5.
Neuroscience ; 250: 20-30, 2013 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-23831422

RESUMO

There is mounting evidence that, in addition to texture and olfaction, taste plays a role in the detection of long chain fatty acids. Triglycerides, the main components of oils and dietary fat, are hydrolyzed in the mouth by a lingual lipase secreted from the von Ebner gland and the released free fatty acids are detected by the taste system. GPR40 and GPR120, two fatty acid responsive G-protein-coupled receptors (GPCRs), are expressed in taste bud cells, and knockout mice lacking either of those receptors have blunted taste nerve responses to and reduced preference for fatty acids. Here we investigated whether activation of those GPCRs is sufficient to elicit fat taste and preference. Five non-fatty acid agonists of GPR40 and two non-fatty acid agonists of GPR120 activated the glossopharyngeal nerve of wild-type mice but not of knockout mice lacking the cognate receptor. In human subjects, two-alternative forced choice (2-AFC) tests, triangle tests and sensory profiling showed that non fatty acid agonists of GPR40 dissolved in water are detected in sip and spit tests and elicit a taste similar to that of linoleic acid, whereas 2-AFC tests showed that two agonists of GPR120 in water are not perceived fattier than water alone. Wild-type mice did not show any preference for five agonists of GPR40, two agonists of GPR120 and mixtures of both agonists over water in two-bottle preference tests. Together these data indicate that GPR40 mediated taste perception is not sufficient to generate preference.


Assuntos
Preferências Alimentares/fisiologia , Receptores Acoplados a Proteínas G/metabolismo , Paladar/fisiologia , Língua/metabolismo , Adolescente , Adulto , Animais , Cálcio/metabolismo , Linhagem Celular , Citoplasma/metabolismo , Ácidos Graxos/farmacologia , Feminino , Humanos , Ácido Linoleico/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/biossíntese , Rosiglitazona , Tiazolidinedionas/farmacologia , Adulto Jovem
6.
G Chir ; 32(8-9): 357-60, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22018255

RESUMO

Researchers believe that human muscle-derived cells are able to restore leak-point pressure to normal levels by differentiating into new muscle fibres that prevent anal sphincter muscle atrophy. Laboratory data are needed to identify exactly how these cells work to regenerate muscle. The objective of this study is to test whether stem cells can be employed to treat internal anal sphincter (IAS) injuries in humans; to this end, this work will use a two-step process to study: first, the effectiveness of the treatment in a sample of animals with artificial injuries to the IAS and then to verify the results in a population of selected humans affected by pathology.


Assuntos
Transplante de Células-Tronco de Sangue do Cordão Umbilical , Incontinência Fecal/cirurgia , Transplante de Células-Tronco Mesenquimais , Canal Anal/fisiopatologia , Canal Anal/cirurgia , Animais , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Dexametasona/farmacologia , Humanos , Hidrocortisona/farmacologia , Modelos Animais , Desenvolvimento Muscular/efeitos dos fármacos , Músculo Esquelético/citologia , Ratos , Ratos Mutantes , Ratos Wistar , Regeneração , Células Satélites de Músculo Esquelético/fisiologia , Imunodeficiência Combinada Severa , Transplante Heterólogo
7.
Eur Rev Med Pharmacol Sci ; 15(1): 61-70, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21381500

RESUMO

OBJECTIVES: One important limitation in cell therapy protocols, and regenerative medicine (an innovative and promising strategy for different pathologies treatment), is the lack of knowledge about cells engraftment, proliferation and differentiation. In order to allow an efficient and successful cell transplant, it is necessary to predict the logistics, economic and timing issues during cellular injection. It has been reported that several parameters, such as cells number, temperature and extracellular pH (pH0) value can influence metabolic pathways and cellular growth. Numerical analysis and model can help to reduce and understand the effects of the above environmental conditions on cell survival. The aim of this paper is to develop the first step of cells transplantation in order to identify "in vitro", which parameters can be useful to develop and validate a numerical model, able to evaluate "in vivo" cells engraftment and proliferation. MATERIAL AND METHODS: We studied the variation of extracellular parameters--such as medium volume, buffer system, nutrient concentrations and temperature on human colon carcinoma cells (CaCo-2) "in vitro culture"--pursuing the goal of understanding in deeper details cellular processes such as growth, metabolic activity, survival and pH0. RESULTS: Results showed that CaCo-2 cells growth and mortality increase after two days in culture when cells were suspended in 3.5 ml volume to respect of 10 ml volume. Different temperature values influenced CaCo-2 cells growth and metabolic activity showing a direct relationship with the volume of the medium. CONCLUSIONS: Our results describe as CaCo-2 cell growth, metabolic activity, mortality and extracellular pH were influenced by extracellular parameters, enabling us to develop and validate a numerical model to be use to predict cells engraftment and proliferation.


Assuntos
Proliferação de Células , Células CACO-2 , Humanos , Concentração de Íons de Hidrogênio , Modelos Biológicos , Temperatura
8.
Neuroscience ; 164(4): 1538-45, 2009 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-19778588

RESUMO

Recent findings highlight the participation of central glial cells in chronic pain, but less is known of a comparable role for satellite glial cells (SGCs), in dorsal root ganglia (DRG). Our previous work showed that sciatic nerve axotomy augmented SGC coupling by gap junctions. The aim of the present research was to find out whether similar changes occur in a mouse inflammation model. Sciatic nerve neuritis was induced by complete Freund's adjuvant (CFA), and isolated ganglia were examined 1 week later. Cell coupling was monitored by intracellular injection of the fluorescent dye Lucifer Yellow. Changes in gap junctions were assessed quantitatively by electron microscopy. Withdrawal threshold in the foot on the side of the inflamed nerve decreased from an average of 3.9 g in control to 0.94 g using Von Frey hairs (P<0.05). In CFA-treated animals dye coupling incidence between SGCs belonging to different glial envelopes increased from 6.9% in controls to 22.5% (P<0.05). Whereas in controls there was no coupling between neurons or between neurons and SGCs, after CFA application the incidence of neuron-neuron and neuron-SGC coupling was 8%. Electron microscopy showed formation of bridges between SGC sheaths surrounding different neurons, which were completely absent in controls. The mean number of gap junctions/100 microm(2) of surface of the section occupied by SGCs increased from 0.215 in controls to 0.709 (P<0.01) in CFA-treated mice. The size of individual gap junctions remained the same. This is the first evidence for ultrastructural changes in SGCs following inflammation. The results support the idea that SGCs are sensitive to a variety of peripheral nerve injuries. We propose that the observed changes may alter signal transmission in DRG and thus may contribute to chronic pain.


Assuntos
Gânglios Espinais/fisiopatologia , Junções Comunicantes/fisiologia , Neuropatia Ciática/fisiopatologia , Animais , Comunicação Celular , Feminino , Corantes Fluorescentes , Gânglios Espinais/patologia , Isoquinolinas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica , Neuropatia Ciática/patologia
9.
Anat Embryol (Berl) ; 211(5): 455-63, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16794842

RESUMO

The volumes of the nerve cell bodies and those of the enveloping satellite cell sheaths from spinal ganglia were determined by morphometric methods applied to electron micrographs in young, adult, old and very old rabbits. The mean volume of the nerve cell bodies increased progressively with age; this is probably related to the increase with age of the body size of the rabbits studied. The mean volume of the satellite cell sheaths did not differ significantly in young, adult and old animals, but was significantly smaller in very old animals. It is extremely unlikely that this marked reduction in the volume of the satellite cell sheath is the result of a pathological process. The mean value of the volume ratio between the satellite cell sheaths and the related nerve cell bodies did not differ significantly in young and adult animals, but was significantly smaller in old and very old animals. This ratio was particularly low in very old animals. Our analysis showed that in each age group the volume of the satellite cell sheath is linearly related to the volume of the related nerve cell body. This result suggests that in rabbit spinal ganglia the quantitative relations between glial and nervous tissue are tightly controlled throughout life. It is suggested that ganglionic neurons release signals to influence and control the volume of their associated glial tissue. Since satellite cells have important support roles for the neurons they surround, it is likely that the marked reduction in the volume of perineuronal sheaths in the extremely advanced age is accompanied by a reduction of those roles, with negative consequences for neuronal activity.


Assuntos
Envelhecimento/fisiologia , Gânglios Espinais/citologia , Gânglios Espinais/crescimento & desenvolvimento , Coelhos/fisiologia , Células Satélites Perineuronais/ultraestrutura , Animais , Comunicação Celular/fisiologia , Tamanho Celular , Feminino , Gânglios Espinais/ultraestrutura , Modelos Lineares , Masculino , Microscopia Eletrônica , Neurônios/ultraestrutura , Coelhos/crescimento & desenvolvimento
10.
Tissue Cell ; 38(2): 93-8, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16540138

RESUMO

In view of the central role that mitochondria are thought to play in the ageing process, we investigated changes in mitochondria of spinal ganglion neurons in rabbits aged 1, 3.6, 6.7, and 8.8 years (the latter extremely old). Mitochondrial size increased significantly with age, while mitochondrial structure did not change. The total volume of mitochondria within the perikaryon did not change significantly during life. This indicates that in these neurons mitochondrial degradation was completely compensated by the production of new mitochondria even in the extremely advanced age. We also found that the mean volume of neuronal perikaryon increased markedly with age, so that the mean percentage of perikaryal volume occupied by mitochondria decreased significantly with a difference of about 33% between the youngest and the oldest animals. This decrease is only in very small part due to lipofuscin accumulation, so that the ratio of the total volume of mitochondria to the volume of functionally active cytoplasm decreased with age. The mitochondria of the neurons studied seem therefore unable to adapt their total volume to the volume of functionally active cytoplasm, that increases with age. This result is consistent with the observation that the neurons of old animals have a reduced ability to respond to high energy demands.


Assuntos
Envelhecimento , Gânglios Espinais/ultraestrutura , Mitocôndrias/ultraestrutura , Neurônios/ultraestrutura , Animais , Feminino , Masculino , Coelhos
11.
Neuroscience ; 137(4): 1185-92, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16326013

RESUMO

Glial cells in both central and peripheral nervous systems are connected by gap junctions, which allow electrical and metabolic coupling between them. In spite of the great current interest in aging of the nervous system, the effect of aging on glial cell coupling received little attention. We examined coupling between satellite glial cells in murine dorsal root ganglia using the dye coupling technique and electron microscopy. We studied mice at ages of postnatal 90-730 days. Dye coupling incidence between satellite glial cells associated with a single neuron increased from 24.2% at postnatal day 90 to 50.5% at postnatal day 730. Dye coupling between satellite glial cells that are in contact with two or more neurons increased from 2.7% at postnatal day 90 to 18.6% at postnatal day 730 (P<0.05). Examination of the ganglia with the electron microscope showed that the number of gap junctions per 100 microm2 of surface area of satellite glial cells increased from 0.22 at postnatal day 90 to 1.56 at postnatal day 730 (P<0.01). The mean length of individual gap junctions did not change with age. These results provide strong evidence for an increase of functional coupling between satellite glial cells during life. This increase is apparently due to an increase in the total area of the system of gap junctions connecting these cells.


Assuntos
Envelhecimento/fisiologia , Gânglios Espinais/fisiologia , Junções Comunicantes/fisiologia , Neuroglia/fisiologia , Animais , Carbenoxolona/farmacologia , Corantes , Feminino , Gânglios Espinais/citologia , Gânglios Espinais/crescimento & desenvolvimento , Junções Comunicantes/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal
12.
J Submicrosc Cytol Pathol ; 38(2-3): 109-16, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17784638

RESUMO

The Golgi apparatus of spinal ganglion neurons was studied in 1, 3.6, 6.7, and 8.8-year-old rabbits. The structure of this organelle did not differ in the four age groups examined. While the mean volume of the neuronal perikaryon increased progressively with age, the total volume of the Golgi apparatus remained stable throughout life. As a consequence, the mean percentage of perikaryal volume occupied by this organelle decreased significantly with age. Since the percentage of perikaryal volume occupied by lipofuscin remained at low levels throughout life, the ratio of the total volume of the Golgi apparatus to the functionally active volume of cytoplasm decreased with age. It is possible that this decrease is related to the reduction in neuronal metabolism that occurs in senescence. The age-related quantitative changes in the Golgi apparatus were very similar in large light and in small dark neurons. Finally, neither fragmentation, nor peripheral displacement of the Golgi apparatus was observed with advancing age.


Assuntos
Envelhecimento/fisiologia , Gânglios Espinais/ultraestrutura , Complexo de Golgi/ultraestrutura , Neurônios/ultraestrutura , Coelhos/fisiologia , Animais , Feminino , Gânglios Espinais/fisiologia , Complexo de Golgi/fisiologia , Masculino , Microscopia Eletrônica de Transmissão , Neurônios/fisiologia
13.
Brain Res Bull ; 67(1-2): 19-23, 2005 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-16140158

RESUMO

This study investigated quantitative aspects of the gap junctions between satellite neuroglial cells that envelope the spinal ganglion neurons in rabbits aged 1 year (young), 3.6 years (adult), 6.7 years (old), and 8.8 years (very old). Both the total number of gap junctions present in 30,000 microm2 of surface area occupied by perineuronal satellite cells, and the density of these junctions increased throughout life, including the extremely advanced age. By contrast, the mean length of individual gap junctions did not change with age. Thus, the junctional system which provides morphological support for the metabolic cooperation between satellite cells in rabbit spinal ganglia becomes more extensive as the age of the animal increases. These results support the hypothesis that the gap junctions between perineuronal satellite cells are involved in the spatial buffering of extracellular K+ and in neuroprotection.


Assuntos
Envelhecimento/fisiologia , Diferenciação Celular/fisiologia , Gânglios Espinais/crescimento & desenvolvimento , Gânglios Espinais/ultraestrutura , Junções Comunicantes/ultraestrutura , Células Satélites Perineuronais/ultraestrutura , Animais , Comunicação Celular/fisiologia , Líquido Extracelular/metabolismo , Feminino , Junções Comunicantes/fisiologia , Masculino , Microscopia Eletrônica de Transmissão , Potássio/metabolismo , Coelhos , Células Satélites Perineuronais/fisiologia , Transdução de Sinais/fisiologia , Regulação para Cima/fisiologia
14.
J Cell Physiol ; 204(2): 532-8, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15754325

RESUMO

The wish of this work is the study of the effect of electromagnetic (EMF) radiations at a frequency of 50 Hz on the development of cerebellar granule neurons (CGN). Granule neurons, prepared from newborn rat cerebellum (8 days after birth), were cultured after plate-seeding in the presence of EMF radiations, with the plan of characterizing their cellular and molecular biochemistry, after exposure to the electromagnetic stimulus. Five days challenge to EMF radiations showed, by the cytotoxic glutamate (Glu) pulse test, a 30% decrease of cells survival, while only 5% of mortality was reported for unexposed sample. Moreover, blocking the glutamate receptor (GluR) with the Glu competitor MK-801, no toxicity effect after CGN challenge to EMF radiations and Glu was detected. By patch-clamp recording technique, the Kainate-induced currents from 6 days old exposed CGN exhibited a significant increase with respect to control cells. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses show that EMF exposure of rats CGN, induces a change in both GluRs proteins and mRNAs expression with respect to control. In addition, the use of monoclonal antibody raised against neurofilament protein (NF-200) reveals an increase in NF-200 synthesis in the exposed CGN. All these results indicate that exposure to non-ionizing radiations contribute to a premature expression of GluRs reducing the life span of CGN, leading to a more rapid cell maturation.


Assuntos
Diferenciação Celular/efeitos da radiação , Senescência Celular/efeitos da radiação , Cerebelo/citologia , Neurônios/citologia , Neurônios/fisiologia , Radiação , Animais , Animais Recém-Nascidos , Western Blotting , Células Cultivadas , Técnica Indireta de Fluorescência para Anticorpo , Proteínas de Neurofilamentos/metabolismo , Neurônios/metabolismo , Ratos , Ratos Wistar , Distribuição Tecidual
15.
ScientificWorldJournal ; 4 Suppl 2: 41-7, 2004 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-15517101

RESUMO

In this study, we show the effect of a 1-mT magnetic field AC at 50 Hz on Xenopus laevis tadpole populations. In the course of a 65-day exposure to the field, tadpole survival showed a small, but significant, decrease (p < 0.0004), together with a striking parallel 6-day shift in tadpole maturation frequency and a significant impairment of their metamorphosis. Particularly, metamorphosis was successful for 85% of individuals in the unirradiated tadpole population and for 45% of individuals in the irradiated tadpole population, respectively.


Assuntos
Campos Eletromagnéticos/efeitos adversos , Larva/efeitos da radiação , Metamorfose Biológica/efeitos da radiação , Xenopus laevis/fisiologia , Animais , Cruzamento/métodos , Embrião não Mamífero/fisiologia , Embrião não Mamífero/efeitos da radiação , Feminino , Masculino , Metamorfose Biológica/fisiologia , Doses de Radiação , Radiação não Ionizante/efeitos adversos , Taxa de Sobrevida
16.
J Submicrosc Cytol Pathol ; 36(1): 17-22, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15311670

RESUMO

The gap junctions between perineuronal satellite cells were studied in the spinal ganglia of 12, 42, and 79-month-old rabbits. The mean number of gap junctions per 100 microm2 of surface of the section occupied by satellite cells was significantly greater in old rabbits than young adults. Since the mean length of individual gap junctions did not change with age, the increase in number of gap junctions cannot be due to fragmentation of pre-existing gap junctions but is very likely due to the formation of new gap junctions. The increase in number of gap junctions cannot be related to an increase in number of perineuronal satellite cells since the mean number of these cells is significantly smaller in aged rabbits than in young adults. It is suggested that the increase in number of gap junctions with age may enhance the suggested neuroprotective role of satellite cells towards ganglionic neurons. The present findings, together with previous observations, suggest that the gap junctions between perineuronal satellite cells are dynamic structures, able to adapt to varying neuronal demands and varying environmental conditions.


Assuntos
Envelhecimento/fisiologia , Gânglios Espinais/citologia , Junções Comunicantes/ultraestrutura , Coelhos/fisiologia , Células Satélites Perineuronais/ultraestrutura , Animais , Feminino , Gânglios Espinais/fisiologia , Junções Comunicantes/fisiologia , Masculino , Microscopia Eletrônica de Transmissão , Células Satélites Perineuronais/fisiologia
17.
Tissue Cell ; 36(1): 55-62, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14729453

RESUMO

We studied the ratios between number of neuroglial (=satellite) cells and number and volume of neurons with which they are associated in the spinal ganglia of two species of reptiles (lizard and gecko) and three species of mammals (mouse, rat, and rabbit). In all five species, we found that the number of satellite cells associated with a nerve cell body increased with increasing volume of the latter. This result shows that there is a quantitative balance between neuroglia and nerve tissue in spinal ganglia. This balance seems to be maintained by a tight regulation of the number of satellite cells. We also found that the mean volume of nerve cell body corresponding to a satellite cell was lower for small neurons than for large ones. Since satellite cells metabolically support spinal ganglion neurons, the metabolic needs of small neurons are better satisfied than those of large ones. For a nerve cell body of a given size, the number of associated satellite cells did not differ between the lizard and gecko, nor between the mouse, rat, and rabbit. However, this number was significantly smaller in the reptiles than in the mammals. This result could be explained by the lower metabolic rate in the nervous system of poikilotherms than mammals, or could have a phylogenetic significance. These two interpretations are not mutually exclusive.


Assuntos
Gânglios Espinais/citologia , Neuroglia/citologia , Neurônios/citologia , Animais , Contagem de Células , Tamanho Celular , Lagartos , Camundongos , Coelhos , Ratos , Ratos Endogâmicos , Especificidade da Espécie
18.
J Submicrosc Cytol Pathol ; 35(3): 267-70, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-14690174

RESUMO

We studied the Golgi apparatus in the satellite cell sheaths enveloping spinal ganglion neurons of rabbits aged 12, 42, and 79 months. We found neither structural changes nor indications of peripheral displacement of this organelle with advancing age. The mean percentage of cytoplasmic volume occupied by the Golgi apparatus decreased significantly passing from young adult to old rabbits. This decrease was only in very minor part a consequence of lipofuscin accumulation, so that the ratio between the total volume of the Golgi apparatus and the functionally active volume of cytoplasm decreased with age. The mean cytoplasmic volume of perineuronal satellite cell sheaths did not change significantly with increasing age, whereas the total volume of the Golgi apparatus within these sheaths decreased significantly with age. This decrease strongly suggests that the activity of satellite cells diminishes in old age, further suggesting that these cells are unable to compensate for the decrease in the neuronal metabolism that a number of authors have described in old age.


Assuntos
Envelhecimento/fisiologia , Gânglios Espinais/fisiologia , Complexo de Golgi/fisiologia , Coelhos/fisiologia , Células Satélites Perineuronais/fisiologia , Animais , Citoplasma/fisiologia , Citoplasma/ultraestrutura , Gânglios Espinais/ultraestrutura , Complexo de Golgi/ultraestrutura , Microscopia Eletrônica , Células Satélites Perineuronais/ultraestrutura
19.
Brain Res Bull ; 61(2): 147-51, 2003 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-12832000

RESUMO

We studied mitochondria in the satellite cell sheaths which envelope the spinal ganglion neurons of rabbits aged 12, 42, and 79 months. While the mean cytoplasmic volume of satellite cell sheaths did not change significantly with age, the mean percentage of cytoplasmic volume occupied by mitochondria decreased with age. This decrease is mainly due to a reduction in the total mitochondrial mass and only in minor part is a consequence of lipofuscin accumulation. Mitochondrial structure did not change, while mitochondrial size increased with age. Comparison between mitochondria in nerve cell bodies and those in satellite cell sheaths showed that: (1) the mean percentage of cytoplasmic volume occupied by mitochondria was greater in nerve cell bodies than satellite cell sheaths and the ratio between these two percentages remained constant with advancing age; (2) the total mitochondrial mass was much greater in nerve cell bodies than satellite cell sheaths and the ratio between these two values increased with age; (3) the extent of increase of mitochondrial size with age was similar in nerve cell bodies and satellite cell sheaths. The results of the present study suggest that: (1) the ability of satellite cell sheaths to produce energy decreases with age; (2) the decreased ability of sensory neurons in old animals to meet high energy demands may be partly due to the diminished contribution of their associated satellite cell sheaths.


Assuntos
Envelhecimento/fisiologia , Gânglios Espinais/fisiologia , Mitocôndrias/fisiologia , Neurônios/fisiologia , Células Satélites Perineuronais/fisiologia , Animais , Citoplasma/fisiologia , Citoplasma/ultraestrutura , Gânglios Espinais/crescimento & desenvolvimento , Gânglios Espinais/ultraestrutura , Microscopia Eletrônica , Mitocôndrias/ultraestrutura , Neurônios/ultraestrutura , Coelhos , Células Satélites Perineuronais/ultraestrutura
20.
Anat Embryol (Berl) ; 206(5): 337-47, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12698360

RESUMO

This study investigated satellite cell changes in mouse L4 and L5 spinal ganglia 14 days after unilateral transection of sciatic and saphenous nerves. The ganglia were studied under the electron microscope in single and serial sections, and by dye injection. Satellite cell responses to axon injury of the neurons with which they are associated included the formation of bridges connecting previously separate perineuronal sheaths and the formation of new gap junctions, resulting in more extensive cell coupling. Some possible consequences of these satellite cell reactions are briefly discussed.


Assuntos
Axônios/ultraestrutura , Gânglios Espinais/ultraestrutura , Junções Comunicantes/ultraestrutura , Neurônios/ultraestrutura , Células Satélites Perineuronais/ultraestrutura , Traumatismos da Medula Espinal/patologia , Animais , Axônios/metabolismo , Denervação , Feminino , Corantes Fluorescentes/metabolismo , Gânglios Espinais/metabolismo , Isoquinolinas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica , Neurônios/metabolismo , Células Satélites Perineuronais/metabolismo , Traumatismos da Medula Espinal/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA