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1.
Zhonghua Bing Li Xue Za Zhi ; 52(2): 142-146, 2023 Feb 08.
Artículo en Zh | MEDLINE | ID: mdl-36748134

RESUMEN

Objective: To explore the feasibility and application value of intraoperative direct immunohistochemical (IHC) staining in improving the diagnosis accuracy in difficult cases of bronchiolar adenoma (BA). Methods: Nineteen cases with single or multiple pulmonary ground-glass nodules or solid nodules indicated by imaging in Cancer Hospital of Chinese Academy of Medical Sciences from January to July 2021 and with difficulty in differential diagnosis at frozen HE sections were selected. In the experimental group, direct IHC staining of cytokeratin 5/6 (CK5/6) and p63 was performed on frozen sections to assist the differentiation of BA from in situ/micro-invasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the control group, two pathologists performed routine frozen HE section diagnosis on these 19 cases. The diagnostic results of paraffin sections were used as the gold standard. The sensitivity and specificity of BA diagnosis, consistency with paraffin diagnosis and time used for frozen diagnosis were compared between the experimental group and the control group. Results: The basal cells of BA were highlighted by CK5/6 and p63 staining. There were no basal cells in the in situ/microinvasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the experimental group, the sensitivity and specificity with aid of direct IHC staining for BA were 100% and 86.7%, respectively, and the Kappa value of frozen and paraffin diagnosis was 0.732, and these were significantly higher than those in the control group (P<0.05). The average time consumption in the experimental group (32.4 min) was only 7 min longer than that in the control group (25.4 min). Conclusions: Direct IHC staining can improve the accuracy of BA diagnosis intraoperatively and reduce the risk of misdiagnosis, but require significantly longer time. Thus frozen direct IHC staining should be restricted to cases with difficulty in differentiating benign from malignant diseases, especially when the surgical modalities differ based on the frozen diagnosis.


Asunto(s)
Adenocarcinoma in Situ , Adenocarcinoma Mucinoso , Adenoma , Humanos , Parafina , Sensibilidad y Especificidad , Adenoma/diagnóstico , Adenocarcinoma Mucinoso/diagnóstico , Adenocarcinoma Mucinoso/cirugía , Secciones por Congelación/métodos
2.
Phys Chem Chem Phys ; 22(39): 22390-22398, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-32996475

RESUMEN

Thermoelectric properties of a black phosphorus/blue phosphorus van der Waals heterostructure are investigated by using first-principles calculations and Boltzmann transport theory for both electrons and phonons. It is found that the heterostructure is both energetically and kinetically stable even at higher temperature. Compared with those of the constituent black and blue phosphorus monolayers, the thermoelectric performance of the heterostructure is significantly enhanced due to sharply decreased thermal conductivity caused by the presence of van der Waals interactions, as well as obviously reduced band gaps and multi-valley structures resulting from type-II band alignment. As a consequence, the room temperature ZT value can reach 1.6, which is much higher than those of the components. Furthermore, we obtain ZT over 2.0 in a wide temperature range from 400 to 800 K, and a maximum ZT of ∼3.2 can be realized at 700 K, which is surprisingly good for systems consisting of light elements only.

3.
Fa Yi Xue Za Zhi ; 35(3): 337-343, 2019 Jun.
Artículo en Inglés, Zh | MEDLINE | ID: mdl-31282632

RESUMEN

ABSTRACT: Methamphetamine (MAMP) is a kind of amphetamine-type stimulants (ATS) which contains one chiral carbon atom in its structure. Therefore a pair of enantiomers, S-(+)-MAMP and R-(-)-MAMP exist. R type and S type methamphetamines possess similar physicochemical properties, but has largely different pharmacological and toxic effects. S-(+)-MAMP is the main component of addictive drug "Ice" at present, seriously affecting human health and public safety. The separation analysis and mechanism of toxic effects discussions on MAMP are the current research focuses. This paper reviews the research progress of separation analysis methods and toxic effects of methamphetamine enantiomers to provide reference for forensic study and forensic practice.


Asunto(s)
Metanfetamina/química , Estimulantes del Sistema Nervioso Central , Humanos , Estereoisomerismo , Detección de Abuso de Sustancias
6.
Genet Mol Res ; 13(3): 5128-37, 2014 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-25061737

RESUMEN

This study aimed to investigate the clinical effects and safety review of self-expanding stent surgery in the treatment of extracranial carotid artery stenosis. Seventy-eight patients with carotid artery stenosis were applied with the self-expanding stent for endovascular interventional therapy. Eighty-one stents were implanted into 80 blood vessels of the 78 patients, in which protective umbrellas were used in 56 cases, and the success rate of stent implantation was 100%. The stenosis degree decreased from the preoperative (86.72 ± 9.5%) to the postoperative (13.43 ± 5.62%) stage, and the blood peak velocity of the stenosed vessels decreased from 189.58 ± 13.5 to 83.73 ± 5.61 cm/s. Transient blood pressure and heart rate decreases occurred in 21 cases, continuously low blood pressure and heart rate decreasing occurred in 29 cases, and acute occlusion of the ipsilateral middle cerebral artery occurred in 1 case, which was resolved through thrombolysis and thrombus breaking in time. Over-perfusion symptoms were observed in 13 cases, although without serious complications such as cerebral hemorrhage. The follow-up period continued for 6-32 months, and ultrasonography revealed that 77 cases had no stent-restenosis, while 1 case had restenosis. The application of self-expanding stents had good clinical effects, with fewer complications and higher safety for the treatment of extracranial carotid artery stenosis.


Asunto(s)
Arterias Carótidas/cirugía , Estenosis Carotídea/cirugía , Procedimientos Endovasculares/instrumentación , Stents , Adulto , Anciano , Anciano de 80 o más Años , Velocidad del Flujo Sanguíneo , Presión Sanguínea , Arterias Carótidas/diagnóstico por imagen , Arterias Carótidas/patología , Estenosis Carotídea/diagnóstico por imagen , Estenosis Carotídea/patología , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Resultado del Tratamiento , Ultrasonografía
7.
J Phys Condens Matter ; 33(1): 015601, 2021 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-33052894

RESUMEN

The design of uranium-based thermoelectric (TE) materials presents a novel and intriguing strategy for directly converting nuclear heat into electrical power. Using high-level first-principles approach combined with accurate solution of Boltzmann transport equation, we demonstrate that a giant n-type power factor of 13.8 mW m-1 K-2 and a peak ZT value of 2.2 can be realized in the heavy-fermion UN2 compound at 700 K. Such promising TE performance arises from the large degeneracy (N v = 14) of heavy conduction band coupled with weak electron-phonon interactions, which is in principle governed by the strong Coulomb correlation among the partially filled U-5f electrons in the face-centered cubic structure. Collectively, our theoretical work suggests that the energetic UN2 could serve as both excellent heat source and efficient power convertor, which also uncovers an underexplored area for TE research.

8.
J Phys Condens Matter ; 32(42): 425704, 2020 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-32624508

RESUMEN

Half-Heusler compounds usually exhibit relatively higher lattice thermal conductivity that is undesirable for thermoelectric applications. Here we demonstrate by first-principles calculations and Boltzmann transport theory that the BiBaK system is an exception, which has rather low thermal conductivity as evidenced by very small phonon group velocity and relaxation time. Detailed analysis indicates that the heavy Bi and Ba atoms form a cage-like structure, inside which the light K atom rattles with larger atomic displacement parameters. In combination with its good electronic transport properties, the BiBaK shows a maximum n-type ZT value of 1.9 at 900 K, which outperforms most half-Heusler thermoelectric materials.

9.
J Phys Condens Matter ; 31(38): 385701, 2019 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-31174197

RESUMEN

The electronic and phonon transport properties of graphene-like boron phosphide (BP), boron arsenide (BAs), and boron antimonide (BSb) monolayers are investigated using first-principles calculations combined with the Boltzmann theory. By considering both the phonon-phonon and electron-phonon scatterings, we demonstrate that the strong bond anharmonicity in the BAs and BSb monolayers can dramatically suppress the phonon relaxation time but hardly affect that of electron. As a consequence, both systems exhibit comparable power factors with that of the BP monolayer but much lower lattice thermal conductivities. Accordingly, a maximum ZT value above 3.0 can be realized in both BAs and BSb monolayers at optimized carrier concentration. Interestingly, very similar p - and n-type thermoelectric performance is observed in the BSb monolayer along the zigzag direction, which is of vital importance in the fabrication of thermoelectric modules with comparable efficiencies.

10.
Zhonghua Er Ke Za Zhi ; 56(8): 601-604, 2018 Aug 02.
Artículo en Zh | MEDLINE | ID: mdl-30078242

RESUMEN

Objective: To report clinical feature and results of genetic analysis of 3 patients from 2 families with Finnish variant late infantile neuronal ceroid lipofuscinosis. Methods: The clinical and ultrastructural features of 3 patients with progressive neurodegenerative diseases were retrospectively analyzed from October 2014 to December 2016 in Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center. The whole exon sequencing and Sanger sequencing were used to analyze the molecular genetics of the patients and their parents. Results: The probands were 11 years and 3 moths, 9 years and 1 month,10 years and 1 month old. All were normal at birth, and from 5-6 years old they began to develop "regression of cognition and motion, impaired vision". Physical examination at the first consultation: clear minded butignorant, unable to speak and understand instructions, unable to stand up and sit alone, unable to maintain postureupright. The brain magnetic resonance imaging(MRI) indicated diffuse cerebral and cerebellar atrophy, white matter damage. Blood biochemistry, lactic acid, acid-base balancewere normal. Electron microscopic examination of peripheral blood lymphocytes showed swelling of the nucleus, autophagy, intracellular massive deposits and abnormal vacuoles. Two compound heterozygous c.334C> T (p.Arg112Cys) and c.595C> T (p.Arg199Ter) mutations of CLN5 gene were identified in the two siblings, and the proband 3 was c.335G> A (p.Arg199His) homozyousmutation, which were inherited from their unaffected parents. Conclusions: The 3 cases with Finnish variant late infantileneuronal ceroid lipofuscinosises were normal at birth, cognitive and motor function was regressed at preschool age.Brain MRI showed whole brain atrophy, white matter lesions, there were no bovious difference from other neurodegenerative diseases. Blood biochemistry and pathological examination of lymphocytes had no specific changes. The pathogenic genes were CLN5,most are inherited in autosomal recessive way.


Asunto(s)
Encéfalo , Lipofuscinosis Ceroideas Neuronales , Atrofia , Encéfalo/patología , Niño , Preescolar , Finlandia , Humanos , Lactante , Imagen por Resonancia Magnética , Lipofuscinosis Ceroideas Neuronales/complicaciones , Lipofuscinosis Ceroideas Neuronales/diagnóstico , Lipofuscinosis Ceroideas Neuronales/genética , Estudios Retrospectivos
11.
Biofabrication ; 10(4): 044102, 2018 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-30129928

RESUMEN

An advanced in vitro cervical tumor model was established by 3D printing to study the epithelial-to-mesenchymal transition (EMT), which is a very important stage of dissemination of carcinoma leading to metastatic tumors. A HeLa/hydrogel grid construct composed of gelatin, alginate, Matrigel and HeLa cells was fabricated by forced extrusion in a layer-by-layer fashion. HeLa cells rapidly proliferated, formed spheroids and presented tumorigenic characteristic in the 3D-printed structure. With the supplement of TGF-ß, aggregated HeLa cells started to disintegrate, and some of them changed into fibroblast-like spindle morphology, which indicated that EMT was induced. The down-regulation of epithelial marker E-cadherin, and up-regulation of mesenchymal markers such as snail, vimentin and N-cadherin were all observed in the 3D-printed model, and performed differently in 3D and 2D models. The TGF-ß induced EMT was inhibited by the treatment of disulfiram and EMT pathway inhibitor C19 in a dose dependent manner, showing great potential for future studies of a therapeutic program towards cervical tumor metastasis.


Asunto(s)
Transición Epitelial-Mesenquimal/efectos de los fármacos , Impresión Tridimensional , Factor de Crecimiento Transformador beta/farmacología , Neoplasias del Cuello Uterino/patología , Biomarcadores de Tumor/metabolismo , Forma de la Célula/efectos de los fármacos , Disulfiram/farmacología , Femenino , Células HeLa , Humanos , Esferoides Celulares/efectos de los fármacos , Esferoides Celulares/patología
12.
Clin Cancer Res ; 7(2): 400-6, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11234896

RESUMEN

In t(14;18)-positive lymphoma cells, bcl-2 is expressed from a fusion mRNA transcript containing the full coding sequence of bcl-2 and 3' immunoglobulin sequences. We reported previously that antisense oligodeoxyribonucleotides directed at the bcl-2 translational start site, as well as those targeted to immunoglobulin sequences 3' of the translocation breakpoint, down-regulate bcl-2 and inhibit growth of the t(14;18)-positive lymphoma line WSU-FSCCL in vitro. We have developed a scid mouse model with this human cell line and demonstrate that antisense oligodeoxyribonucleotides targeted to immunoglobulin c(mu) sequences down-regulate bcl-2 protein expression and induce apoptosis of WSU-FSCCL cells in vivo. This leads to prolonged survival of the mice. Targeting non-oncogenic sequences outside of the breakpoints of fusion transcripts may be a clinically useful therapeutic strategy.


Asunto(s)
Cromosomas Humanos Par 14 , Cromosomas Humanos Par 18 , Genes bcl-2 , Fragmentos de Inmunoglobulinas/genética , Linfoma/tratamiento farmacológico , Oligonucleótidos Antisentido/uso terapéutico , Proteínas de Fusión Oncogénica/genética , Inmunodeficiencia Combinada Grave/tratamiento farmacológico , Animales , Apoptosis/inmunología , Western Blotting , Regulación hacia Abajo , Femenino , Citometría de Flujo , Expresión Génica , Humanos , Immunoblotting/métodos , Ratones , Ratones SCID , Análisis de Supervivencia , Células Tumorales Cultivadas
13.
J Leukoc Biol ; 44(1): 27-32, 1988 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3260616

RESUMEN

Previous studies have shown that the injection of estrogen into immature rats leads to an influx of leukocytes into the uterus. Using immunoperoxidase staining and monoclonal antibodies, we have characterized the nature of the infiltrating leukocytes in frozen sections of immature rat uteri obtained following the injection of estrogen, estrogen plus pertussigen, and the antiestrogen LY117018. Estradiol treatment for 2 days resulted in a significant increase in the number of uterine eosinophils, CD4 (W3/W25)-positive helper/inducer T lymphocytes, macrophages (MRC OX-42-positive cells), and Ia (MRC OX-6)-positive cells. In contrast, estradiol treatment failed to elicit a significant increase in the number of CD8 (MRC OX-8)-positive uterine cytotoxic/suppressor T lymphocytes and/or natural killer cells, as well as MAR 18.5- and/or MRC OX-12-positive B lymphocytes. The injection of LY117018 failed to elicit any changes in the number of cells expressing any of the phenotypes under investigation. The simultaneous injection of pertussigen, the major toxin responsible for the leukocytosis- and lymphocytosis-promoting activity of Bordetella pertussis, inhibited the estrogen-induced influx of eosinophils, macrophages (MRC OX-42-positive cells), and Ia (MRC OX-6)-positive cells but failed to prevent the influx of CD4 (W3/25) positive helper/inducer T lymphocytes. These results indicate that, in the immature rat, significant differences may exist in the susceptibility of various cell populations to the effects of estrogen, particularly with regard to uterine influx following estrogen stimulation. In addition, our observations suggest that either 1) the CD4-positive cells infiltrating the uterus following estrogen treatment may use a nonpertussigen-sensitive mechanism for chemotactic factor-receptor signal transduction or 2) a subpopulation of resident uterine cells can be induced to express the CD4 antigen following estrogen and/or estrogen plus pertussigen treatment.


Asunto(s)
Estrógenos/farmacología , Leucocitos/efectos de los fármacos , Útero/efectos de los fármacos , Animales , Antígenos de Diferenciación de Linfocitos T/análisis , Movimiento Celular/efectos de los fármacos , Femenino , Antígenos de Histocompatibilidad Clase II/análisis , Inmunohistoquímica , Leucocitos/fisiología , Toxina del Pertussis , Pirrolidinas/farmacología , Ratas , Ratas Endogámicas , Tiofenos/farmacología , Útero/citología , Factores de Virulencia de Bordetella/farmacología
14.
Endocrinology ; 135(5): 2240-7, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7956947

RESUMEN

Transforming growth factor-beta 1 (TGF beta 1) is a potent modulator of cell proliferation, differentiation, angiogenesis, and the immune system. TGF beta 1 messenger RNA (mRNA) levels were much higher in several rat prostate adenocarcinomas (Dunning R3327 MATLyLu, AT2, G, HI, and H sublines) than in normal prostate. Normal prostate and the well differentiated H and HI tumors produced two TGF beta 1 mRNA transcripts, 2.4 kilobases (major) and 1.6 kilobases (minor). The poorly differentiated MATLyLu and AT2 sublines produced these plus additional TGF beta 1 mRNA transcripts that were present in the primary tumors, metastases, and cultured cell lines. TGF beta 1 mRNA levels were unchanged 2 weeks after castration. Immunohistochemical staining of TGF beta 1 protein was more prominent and more extensive in prostate cancer than in normal prostate. Only extracellular TGF beta 1 staining was detected. In normal prostate and in well differentiated tumors (H and HI), extracellular TGF beta 1 staining was located in the interacinar stroma, suggesting that it may be produced there. In contrast, in the poorly differentiated tumors (MATLyLu, AT2, and G) that contain sheets of epithelial cells, extracellular TGF beta 1 staining was present throughout the tumor, suggesting that TGF beta 1 may be made and secreted by the tumor epithelial cells. MATLyLu, AT2, and G tumor cells were cultured in vitro, and the conditioned medium was analyzed for the presence of TGF beta using a bioassay. TGF beta 1 is produced and secreted as an inactive latent precursor and must be activated to release bioactive TGF beta 1. Cells secreted about 100-500 pg TGF beta/10(6) cells.24 h and were able to activate about 50% of the total TGF beta secreted. Because TGF beta 1 mRNA and protein expression are higher in cancerous than normal tissue and because prostate cancer cells themselves can activate latent TGF beta 1 to a bioactive form, TGF beta 1 produced endogenously by prostate cancer has the potential to affect tumor behavior in vivo. Therefore, TGF beta 1 may represent a new therapeutic target in prostate cancer.


Asunto(s)
Adenocarcinoma/química , Adenocarcinoma/patología , Neoplasias de la Próstata/química , Neoplasias de la Próstata/patología , Factor de Crecimiento Transformador beta/análisis , Animales , ADN de Neoplasias/análisis , ADN de Neoplasias/genética , Regulación Neoplásica de la Expresión Génica , Inmunohistoquímica , Masculino , ARN Mensajero/análisis , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Factor de Crecimiento Transformador beta/genética , Células Tumorales Cultivadas
15.
Autoimmunity ; 3(2): 125-34, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2491624

RESUMEN

Active experimental allergic orchitis (EAO) was induced in Lewis/NCr rats by immunization with homologous rat testicular homogenate. Groups of animals were studied sequentially at five day intervals for histopathologic signs of disease. Inflammatory lesions were first observed in the ductus efferentes as early as 5 days following immunization. Immunohistochemical analysis of the testes, rete testis, ductus efferentes and caput, corpus and cauda epididymis of immunized rats on day five revealed that only the ductus efferentes exhibited a significant increase in the number of interstitial cells expressing Ia antigens (MRC OX-6) as well as CD4 (W3/25) positive helper/inducer T lymphocytes, CD8 (MRC OX-8) positive cytotoxic T lymphocytes and/or natural killer cells and macrophages (MRC OX-42). Increased staining for Ia antigens was also associated with both the vascular and ductal epithelial cells whereas cells within the lumen of the ducts were consistently negative for Ia antigen expression. In contrast, there was no detectable increase in the level of expression of rat MHC class I antigens (MRC OX-18) by any of the cells of the ductus efferentes. Similarly, there was no increase in the number of MAR 18.5 and/or MRC OX-12 positive B lymphocytes. By day 15, autoimmune epididymitis was observed in the cauda and corpus epididymis with the caput becoming involved by day 20. In the testes, the first histopathologic changes observed were scattered inflammatory infiltrates on day 15 and scattered foci of aspermatogenesis on day 20. Inflammatory lesions were first seen in the rete testis and the seminiferous tubules on day 25-30 with maximal involvement occurring on day 35-40. Early inflammatory lesions in the seminiferous tubules were characterized by peritubular and/or interstitial mixed cellular infiltrates. Later lesions included granuloma formation and necrosis. Autoimmune vasitis was not seen in any of the animals studied. Control rats immunized with rat liver homogenate plus adjuvants or adjuvants alone did not exhibit any of the histopathologic lesions described above. The observed results, when compared to those of previous studies examining the sequential histo- and immunopathology of active EAO in the guinea pig and mouse, support the concept that: 1) significant species specificity may exist with regard to regional differences in susceptibility to autoimmune attack within the male reproductive tract and 2) that such differences correlate with early maximal expression of Ia by cells within the male reproductive tract.


Asunto(s)
Enfermedades Autoinmunes/inmunología , Orquitis/inmunología , Animales , Enfermedades Autoinmunes/etiología , Enfermedades Autoinmunes/patología , Antígenos de Histocompatibilidad Clase II/metabolismo , Inmunohistoquímica , Infertilidad Masculina/etiología , Masculino , Orquitis/etiología , Orquitis/patología , Ratas , Ratas Endogámicas Lew , Factores de Tiempo
16.
Peptides ; 6(2): 337-41, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-4034415

RESUMEN

Fractionation on Sephadex G50 gel of methanol extracts of guinea pig intestine reveals two molecular forms of cholecystokinin (CCK) of about equal abundance. One elutes at the position of CCK8 while the other elutes at a position intermediate between CCK33 and CCK8. Purification and sequencing of these peptides identify them as CCK8 and CCK22, respectively. Guinea pig CCK8 differs from other mammalian CCK octapeptides isolated thus far in that there is a valine substituted for methionine at position 6 from the C-terminus. In addition to the substitution in CCK8, serine is substituted for asparagine in position 22, glycine for serine in position 19, and asparagine for serine in position 15 from the C-terminus compared to the pig sequence. HPLC separation on a C18 column yields two peaks each of CCK8 and of CCK22 in pig intestinal tissue obtained from a commercial supplier. The two CCK8 peptides have identical amino acid sequences as do the two CCK22 peptides. The CCK22 peptides are equally bioactive in the guinea pig pancreatic acinar cell assay but are about 10-fold less potent than synthetic CCK8(s). One of the guinea pig CCK8 peptides is fully bioactive whereas the other is about 50-fold less potent compared to synthetic CCK8(s).


Asunto(s)
Colecistoquinina/análogos & derivados , Colecistoquinina/aislamiento & purificación , Intestinos/análisis , Secuencia de Aminoácidos , Animales , Cromatografía por Intercambio Iónico , Cobayas , Radioinmunoensayo , Sincalida/aislamiento & purificación
17.
Health Phys ; 56(5): 683-6, 1989 May.
Artículo en Inglés | MEDLINE | ID: mdl-2708057

RESUMEN

The effects of pulsed radiation on animal models were studied. Erythemic responses to laser radiation were observed macroscopically and were examined histologically by both light and electron microscopy. Based on statistical analysis of the biological data presented in this study, skin damage thresholds were calculated for short pulses with lasers at wavelengths of 265 nm and 308 nm.


Asunto(s)
Rayos Láser/efectos adversos , Piel/efectos de la radiación , Rayos Ultravioleta/efectos adversos , Animales , Eritema/etiología , Concentración Máxima Admisible , Porcinos
18.
Circ Shock ; 32(1): 55-66, 1990 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2208607

RESUMEN

In vivo and in vitro studies have shown that the vascular response to catecholamine is attenuated during endotoxemia. The mechanism of such attenuation is complex and might involve high catecholamine-induced desensitization of adrenoceptors. The purpose of this study was to assess the vascular response to adrenergic stimulation after endotoxin (ETX) administration in pithed rats. In pithed rats, sympathetic outflow is controlled by stimulation, ETX does not elevate norepinephrine (NE), and there are no compensatory reflexes. Rats were pithed, curarized, and adrenal-demedullated. Preganglionic thoracolumbar nerves were stimulated (3 Hz, 10 V, 0.5 msec) for 1 hr after pithing, at which time the first set of frequency and NE-dose responses were assessed by measuring the peak increase in diastolic blood pressure. Intravenous ETX (1.5 mg/kg or 0.5 mg/kg) or saline was administered immediately after these measurements. A sham group was designed to mimic the falling blood pressure pattern seen in the endotoxin group during 1 hr after ETX was given by gradually decreasing the stimulation frequency. The second set of frequency and NE-dose responses were evaluated 1 hr after ETX, saline, or sham treatment. Plasma NE and epinephrine (EPI) were determined before and 1 hr after ETX (1.5 mg/kg) or saline injection. The results showed that blood pressure response to adrenergic stimulation was markedly attenuated in pithed rats following both high and low doses of ETX compared with the saline and sham groups. Plasma NE was not elevated by ETX insult in pithed rats. We propose that mechanisms other than high-catecholamine-induced adrenergic desensitization or hypotension account for the attenuated adrenergic responsiveness of the vasculature following ETX.


Asunto(s)
Encéfalo/fisiología , Endotoxinas/farmacología , Hemodinámica/fisiología , Norepinefrina/farmacología , Médula Espinal/fisiología , Animales , Presión Sanguínea , Encéfalo/cirugía , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Endotoxinas/administración & dosificación , Epinefrina/sangre , Frecuencia Cardíaca , Masculino , Norepinefrina/administración & dosificación , Norepinefrina/sangre , Ratas , Médula Espinal/cirugía , Sistema Nervioso Simpático/fisiología
19.
Am J Physiol ; 265(3 Pt 2): R683-8, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8214164

RESUMEN

The contribution of central vs. peripheral mechanisms in mediating increases in plasma norepinephrine (NE) and epinephrine (Epi) during endotoxicosis were studied. Plasma catecholamine responses after endotoxin were assessed in conscious animals and in animals without central regulatory mechanisms (pithed rats). In conscious rats, endotoxin (1.5 mg/kg i.v.) induced a marked elevation in plasma NE after 90 min (3-fold), but elevations were not seen in pithed rats. Endotoxin also induced a profound increase (12- to 13-fold) in plasma Epi in conscious rats, but increases were less (2- to 3-fold) and delayed in pithed rats. These results suggest that central mechanisms are essential in plasma NE response to endotoxic challenge, whereas plasma Epi response involves both central and peripheral mechanisms, with the former being dominant. In conscious adrenal-denervated animals, plasma Epi was not elevated until 90 min postendotoxin. This delayed Epi elevation was approximately one-third of the maximal response observed in conscious adrenal-intact rats. In pithed adrenal-denervated rats, plasma Epi at 90 min postendotoxin was also increased to a level comparable to that in pithed adrenal-intact rats. These results imply that a significant fraction of peripheral release of Epi with endotoxicosis is nonneurogenic.


Asunto(s)
Glándulas Suprarrenales/fisiología , Encéfalo/fisiología , Endotoxinas/farmacología , Sistema Nervioso Simpático/fisiología , Glándulas Suprarrenales/inervación , Animales , Estado de Descerebración , Desnervación , Epinefrina/sangre , Hemodinámica/efectos de los fármacos , Masculino , Norepinefrina/sangre , Ratas , Ratas Endogámicas
20.
J Auton Nerv Syst ; 39(1): 1-12, 1992 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-1629520

RESUMEN

We examined the contributions of arterial baroreceptor reflexes in mediating sympathoadrenal activation during endotoxicosis. Conscious rats with chronic sinoaortic denervation (SAD) or sham-operation (SHAM) were subject to endotoxin treatment (5 mg/kg, i.v.). Hemodynamic responses, renal sympathetic nerve activity (RSNA) and plasma catecholamines were assessed at different times post endotoxin infusion. In both SAD and sham groups, intravenous endotoxin injection induced a rapid and significant sympathoadrenal activation, as indicated by a parallel elevation of RSNA and plasma catecholamines. Such activation peaked 15-30 min following endotoxin and was sustained throughout the 2-3 h protocol. The early response of the sympathoadrenal system to endotoxin is more profound in SAD rats compared to sham rats. We propose that the afferent neural input from arterial baroreceptors is not essential in mediating sympathoadrenal activation during sepsis. The elimination of feedback buffering mechanisms with SAD may account for the augmented sympathetic response seen in SAD animals.


Asunto(s)
Endotoxinas/toxicidad , Presorreceptores/fisiología , Reflejo/fisiología , Salmonella enteritidis , Sistema Nervioso Simpático/fisiopatología , Vías Aferentes/fisiología , Animales , Catecolaminas/sangre , Desnervación , Hemodinámica/efectos de los fármacos , Riñón/inervación , Riñón/fisiopatología , Masculino , Ratas , Nodo Sinoatrial/fisiología , Sistema Nervioso Simpático/efectos de los fármacos
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