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Boletin de estudios medicos y biologicos最新文献

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Nickel chloride: potential accumulation from the airway. Toxicokinetics in rats. 氯化镍:可能从气道积聚。大鼠的毒性动力学。
Boletin de estudios medicos y biologicos Pub Date : 1991-01-01
E B Novelli, N L Rodrigues
{"title":"Nickel chloride: potential accumulation from the airway. Toxicokinetics in rats.","authors":"E B Novelli,&nbsp;N L Rodrigues","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The rate removal of nickel from the airway was measured in vivo. Removal in vivo was studied by intratracheal injection of nickel chloride solutions. Regardless of time after injection, the lungs and heart retained the greatest concentration of nickel and 40 days after 1.68 mumol administration they were the organs where nickel was still significantly measurable. The slow removal of nickel may indicate the presence of high affinity binding sites in the lung. Nickel can interact with others metals, such as copper and zinc, so that nickel exposure may have public health implications.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"39 1-4","pages":"15-20"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12976249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Diazepam effect upon the microscopic structure of the mouse placenta. 安定对小鼠胎盘显微结构的影响。
Boletin de estudios medicos y biologicos Pub Date : 1991-01-01
M C Márquez-Orozco, A Márquez-Orozco, M V Gazca-Ramírez
{"title":"Diazepam effect upon the microscopic structure of the mouse placenta.","authors":"M C Márquez-Orozco,&nbsp;A Márquez-Orozco,&nbsp;M V Gazca-Ramírez","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>CD-1 strain, female mice, aged 5 to 7 months, were mated with males of the same age. Females presenting vaginal plug were separated and randomly distributed in two groups to be treated from the 6th to 17th day of gestation. One group received single daily diazepam doses (2.7 mg/kg i.p.), the other, 0.9% saline in equivalent volumes. Females were killed on 18th day, the placentas removed and fixed in 10% formaldehyde, pH 7.3, dehydrated and embedded in paraplast; 3 microns thick sections were stained with hematoxylin-eosin and Weigert hematoxylin and analyzed under light microscopy. Placentas of the diazepam-treated females presented dilated chorion vessels and intervillous spaces. Trophoblastic cell nuclei presented chromatin in coarse granules, atypically distributed in the karyolymph, which had lesser staining affinity. Giant cells showed vacuolized cytoplasm and coarsely granulated chromatin. Results indicate that diazepam causes structural changes, possibly placental and fetal physiology.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"39 1-4","pages":"21-7"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12976250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Episodic prolactin release after removal of dopamine inhibition in vitro. 体外解除多巴胺抑制后的发作性催乳素释放。
Boletin de estudios medicos y biologicos Pub Date : 1990-07-01
K C Swearingen, G Martínez de la Escalera, R I Weiner
{"title":"Episodic prolactin release after removal of dopamine inhibition in vitro.","authors":"K C Swearingen,&nbsp;G Martínez de la Escalera,&nbsp;R I Weiner","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Prolactin (PRL) release following the removal of tonic dopamine (DA) inhibition was investigated in superfused cultures of dispersed rat anterior pituitary cells. The removal of DA (500 nM) inhibition resulted in a rapid and sustained increased in PRL release as measured by RIA which occurred in an episodic manner. The first PRL pulse reached a maximum 15 to 30 min. after DA removal (20.6 +/- 1.1 min). The second pulse occurred 40 to 45 min. after DA removal and the mean interpulse period was 21.7 +/- 1.2 min. The amplitude of the first pulse was 1.6 to 13.5 higher than the value observed in the presence of DA. It was followed by a nadir that was 1.1 to 8.0 fold higher than the basal value. The second pulse was of slightly lower amplitude, reaching a maximum of 2.3 to 8.0 fold over the control value and 1.25 to 2.5 fold over the preceding nadir. This episodic pattern was observed in 16 independent experiments performed with cells cultured at a density of 0.7-2.8 x 10(6) cells/coverslip. We hypothesize that lactotrophs in vitro have an inherent 20 minute secretory rhythm as has been observed under certain circumstances in vivo. Tonic dopamine inhibition restrains the otherwise random secretory rhythms of lactotrophs thereby synchronizing the secretory phase of the cells upon its removal. Consistent with this hypothesis episodic PRL release was not observed when DA was constantly present or absent.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 3-4","pages":"43-8"},"PeriodicalIF":0.0,"publicationDate":"1990-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13259104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Histology of rat placentas treated with methylhydrazine Ro 4-6467. 甲基肼ro4 -6467对大鼠胎盘组织的影响。
Boletin de estudios medicos y biologicos Pub Date : 1990-07-01
E Estrada-Flores, C Yáñez Mendoza
{"title":"Histology of rat placentas treated with methylhydrazine Ro 4-6467.","authors":"E Estrada-Flores,&nbsp;C Yáñez Mendoza","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The placenta is a vascular organ within the uterus, connected to the fetus by the umbilical cord; it is the structure through which the fetus is nourished. In the rat placenta, three regions can be identified: the decidua basalis, the basal zone, and the labyrinth. In the present work, doses of 4.2 mg/kg of Natulán (Roche), as used for human therapy, were administered orally to pregnant rats. The number of glycogenic cells from the basal zone of the placenta was increased, which allows us to suggest that Natulán causes an inhibition of glycolysis, by blocking the metabolism of the placenta, as proposed by Warburg.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 3-4","pages":"59-64"},"PeriodicalIF":0.0,"publicationDate":"1990-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13259724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Pancreas damage and intratracheal NiCl2 administration. Effects of nickel chloride. 胰腺损伤和气管内NiCl2给药。氯化镍的影响。
Boletin de estudios medicos y biologicos Pub Date : 1990-07-01
E L Novelli, J M Sforcin, N L Rodrigues, B O Ribas
{"title":"Pancreas damage and intratracheal NiCl2 administration. Effects of nickel chloride.","authors":"E L Novelli,&nbsp;J M Sforcin,&nbsp;N L Rodrigues,&nbsp;B O Ribas","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Changes in activities of Cu-Zn superoxide dismutase (SOD- E.C.1.15.1.1.) and lactate dehydrogenase (LDH- E.C.1.1.1.27.) and levels of copper, total protein, triglycerides, phospholipids and total lipids were investigated in pancreas of rats after intratracheal administration of NiCl2 (8.4 mumol/kg). Nickel chloride induced increased SOD activity in pancreas and erythrocytes. This elevation was related to increased copper and decreased phospholipid content in pancreas of these animals. In conclusion, the ability of an animal to tolerate nickel chloride induced damage was governed by a delicate balance between the generation of cytotoxic agents and the various pancreas defense capabilities.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 3-4","pages":"54-8"},"PeriodicalIF":0.0,"publicationDate":"1990-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13125039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Over-reinforcement protects against memory deficits induced by muscarinic blockade of the striatum. 过度强化可防止毒蕈碱阻断纹状体引起的记忆缺陷。
Boletin de estudios medicos y biologicos Pub Date : 1990-07-01
M A Díaz del Guante, S Rivas-Arancibia, G Quirarte, R A Prado-Alcalá
{"title":"Over-reinforcement protects against memory deficits induced by muscarinic blockade of the striatum.","authors":"M A Díaz del Guante,&nbsp;S Rivas-Arancibia,&nbsp;G Quirarte,&nbsp;R A Prado-Alcalá","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>It has been shown that blockade of muscarinic receptors of the anterior striatum (AS) induces significant impairments in the retrieval of stored information of a passive avoidance task, trained with conventional parameters of footshock, and that the same blockade is ineffective in altering short-term memory of this task. The results of the present experimental series showed that in conditions of over-reinforcement, microinjections of scopolamine into the AS shortly after training or before retention testing of passive avoidance, do not produce memory deficits when retention is assessed 30 min, 24 h or 48 h after training. It is suggested that after an enhanced learning experience (over-reinforcement) striatal cholinergic activity is not involved in short- and long-term memory functions.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 3-4","pages":"49-53"},"PeriodicalIF":0.0,"publicationDate":"1990-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13259722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Review article: structural and functional properties of cytochrome aa3 from bacteria. 综述文章:细菌细胞色素aa3的结构和功能特性。
Boletin de estudios medicos y biologicos Pub Date : 1990-01-01
J A García-Horsman, E Escamilla
{"title":"Review article: structural and functional properties of cytochrome aa3 from bacteria.","authors":"J A García-Horsman,&nbsp;E Escamilla","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The aa3 oxidases from bacteria form a group of related enzymes that resemble the far more complex mitochondrial cytochrome c oxidase, both functionally and structurally. These enzymes catalyze electron transfer from ferrocytochrome c to oxygen to produce water. This transfer is coupled to proton translocation. Several oxidases of this type have been purified from cytoplasmic membranes of bacteria. This review summarizes the present knowledge on purified bacterial aa3 oxidases and correlates these findings with data available for the eukaryotic cytochrome c-oxidases.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 1-2","pages":"29-40"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13121636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effects of neonatal undernutrition on the electrocortical development of the association areas in the rat. 新生儿营养不良对大鼠关联区电皮质发育的影响。
Boletin de estudios medicos y biologicos Pub Date : 1990-01-01
M Salas, A Rosales, C Torrero, S Pulido
{"title":"Effects of neonatal undernutrition on the electrocortical development of the association areas in the rat.","authors":"M Salas,&nbsp;A Rosales,&nbsp;C Torrero,&nbsp;S Pulido","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The electrocortical effects provoked by neonatal undernutrition and the environmental sensorial stimuli were studied in the cortical association areas of developing Wistar rats. When the interaction between these two factors was interfered (Experiment 1), the average frequency of the ECoG in the early starved rats was significantly increased than controls. Moreover, if these two factors were combined (Experiment 2) not significant differences in the ECoG average frequencies were observed. The data suggest that the maturation of cells underlying the ECoG in the association areas of the rat, requires not only an adequate supply of nutrients, but also the influence of sensory cues arising from the mother, littermates and the environmental surrounding.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 1-2","pages":"3-9"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13442787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Electron paramagnetic resonance of the mitochondrial respiratory chain in the presence of phenazine methosulfate. 非那嗪甲硫代硫酸钠存在时线粒体呼吸链的电子顺磁共振。
Boletin de estudios medicos y biologicos Pub Date : 1990-01-01
D Jay, R Zamorano, E Muñoz, R Gleason, J L Boldu
{"title":"Electron paramagnetic resonance of the mitochondrial respiratory chain in the presence of phenazine methosulfate.","authors":"D Jay,&nbsp;R Zamorano,&nbsp;E Muñoz,&nbsp;R Gleason,&nbsp;J L Boldu","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The EPR spectra of phenazine methosulfate (PMS) generated under different conditions, as reduction or excitation with light were studied. In addition, results show the EPR spectra of reduced-submitochondrial particles and reduced-submitochondrial particles in the presence of PMS. Combined systems of this last type have been repeatedly utilized in EPR studies. This work proves that such systems give rise to characteristic signals around g = 2, which behaviour reflects the presence of particular prosthetic groups of the respiratory chain combined with the reduced dye. The consequences of these findings are discussed.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 1-2","pages":"16-21"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13121634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Ketamine antagonizes toxic action of anticholinesterase agents. 氯胺酮可拮抗胆碱酯酶药物的毒性作用。
Boletin de estudios medicos y biologicos Pub Date : 1990-01-01
C M Contreras, M L Marvan, G Mexicano, A Puente, A Morfin
{"title":"Ketamine antagonizes toxic action of anticholinesterase agents.","authors":"C M Contreras,&nbsp;M L Marvan,&nbsp;G Mexicano,&nbsp;A Puente,&nbsp;A Morfin","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Ketamine is an anaesthetic interacting with several neurotransmitters. Among others, ketamine exerts some cholinergic actions (ACh). This paper presents the results of studying the interaction of ketamine with ACh in two animal species. Atropine slightly increased the time of immobility produced by ketamine injections in rats. Meanwhile, neostigmine slightly decreased such immobility. Ketamine resulted similar in behavioral actions and shared some electroencephalographic (EEG) actions of scopolamine in cats. The most striking interaction consisted on an antagonism of ketamine on the action of anticholinesterase agents. In both species, ketamine blocked the EEG and the behavioral toxic effects of neostigmine and physostigmine. Notwithstanding, the anticholinesterase agents were unable in reducing the actions of ketamine. This partial cholinergic agonist action of ketamine support certain but limited use of the anesthetic against insecticidal anticholinesterase poisoning.</p>","PeriodicalId":75608,"journal":{"name":"Boletin de estudios medicos y biologicos","volume":"38 1-2","pages":"10-5"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13442783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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