Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
1.
Br Poult Sci ; 64(5): 586-593, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37334805

RESUMO

1. The Forkhead box O3 (FOXO3) transcription factor is a crucial regulator in controlling cell metabolism, proliferation, apoptosis, migration and response to oxidative stress. However, FOXO3 has not previously been studied much in the embryonic skin follicles of geese.2. This study used Zhedong white geese (Anser cygnoides), Jilin white geese (Anser cygnoides) and Hungarian white geese (Anser anser). The feather follicle structure in the dorsal skin during embryonic stages was examined with haematoxylin and eosin (HE) and Pollak staining. The FOXO3 protein content in the embryonic dorsal skin from feather follicles was detected using western blotting and quantitative real-time PCR.3. The mRNA expression level of FOXO3 in the dorsal skin of Jilin white geese was highly expressed on embryonic day 23 (E23; P < 0.01), while mRNA expression of FOXO3 was highly expressed in the feather follicle of Hungarian white geese at E28 (P < 0.01). The expression of FOXO3 protein mainly concentrated in the early embryonic phase among these goose breeds (P < 0.05). This suggested that FOXO3 plays a crucial role in the development and growth of embryonic dorsal skin of feather follicles. The location of the FOXO3 protein was determined using the IHC technique, which further verified the effect of FOXO3 in the dorsal skin for feather follicles during embryogenesis.4. The study demonstrated the differential expression and localisation of the FOXO3 gene among different goose species. It was speculated that the gene could potentially improve goose feather follicle development and feather-related traits and provide a basis for further understanding of FOXO3 function in the dorsal tissue of goose embryos.


Assuntos
Galinhas , Gansos , Animais , Gansos/fisiologia , Proteína Forkhead Box O3/genética , Proteína Forkhead Box O3/metabolismo , Galinhas/genética , Desenvolvimento Embrionário/genética , Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
2.
N Z Vet J ; 67(5): 257-263, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31208293

RESUMO

Aim: To compare the pharmacokinetic profiles of tilmicosin, administered orally at a single dose of 20 mg/kg bodyweight, in healthy pigs and in pigs experimentally infected with Actinobacillus pleuropneumoniae. Methods: Twelve healthy crossbred pigs, aged approximately 8 weeks, were randomly assigned to uninfected and infected groups, with six pigs per group. Pigs in the infected group were inoculated intranasally with a bacterial suspension of A. pleuropneumoniae containing approximately 108 cfu. Each pig received a single oral dose of 20 mg/kg bodyweight of tilmicosin, given 3-4 hours after inoculation in infected pigs. Blood samples were collected before drug administration and up to 48 hours after tilmicosin administration. Concentrations of tilmicosin in plasma samples were determined by HPLC. Throughout the experimental period pigs were observed for signs of inappetence and clinical abnormalities. After sampling was complete pigs were subject to euthanasia and samples collected for gross and histopathology as well as microbiology. Results: Infected pigs showed signs of bradykinesia, nasal discharge dyspnoea, and coughing 1 hours after inoculation and A. pleuropneumoniae was cultured from the lungs of all infected pigs postmortem. Comparing pharmacokinetic parameters in uninfected and infected pigs, the maximum plasma concentration of tilmicosin was higher in uninfected pigs (1.17 (SD 0.17) vs. 0.96 (SD 0.17) µg/mL), the time to reach maximum concentration was shorter (1.53 (SD 0.23) vs. 2.40 (SD 0.37) hours), and the half-life of the absorption phase and half-life of the elimination phase were both shorter (0.66 (SD 0.08) vs. 1.00 (SD 0.27) hours) and (12.93 (SD 0.96) vs. 16.53 (SD 0.55) hours), respectively. The apparent volume of distribution was smaller in uninfected than infected pigs (1.91 (SD 0.22) vs. 2.16 (SD 0.21) L/kg). The relative bioavailability of tilmicosin in infected relative to uninfected pigs was 108.6 (SD 9.71)%. Conclusions and clinical relevance: The results of this study indicate that A. pleuropneumoniae infection significantly changed certain pharmacokinetic parameters of tilmicosin in pigs. In infected pigs tilmicosin exhibited a longer drug persistence and a better extent of absorption. These results indicate that it is necessary to monitor and adjust the dose of tilmicosin administration during the presence of pleuropneumonia. It is expected that this can optimise clinical efficacy and help avoid the development of resistance.


Assuntos
Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/efeitos dos fármacos , Antibacterianos/farmacocinética , Doenças dos Suínos/tratamento farmacológico , Tilosina/análogos & derivados , Infecções por Actinobacillus/tratamento farmacológico , Animais , Antibacterianos/sangue , Autopsia/veterinária , China , Cromatografia Líquida de Alta Pressão/veterinária , Modelos Animais de Doenças , Feminino , Meia-Vida , Pulmão/microbiologia , Masculino , Distribuição Aleatória , Suínos , Doenças dos Suínos/microbiologia , Tilosina/sangue , Tilosina/farmacocinética
3.
Eur Respir J ; 32(2): 285-95, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18321928

RESUMO

Transforming growth factor (TGF)-beta signalling plays important roles in regulating lung development. However, the specific regulatory functions of TGF-beta signalling in developing lung epithelial versus mesenchymal cells are still unknown. By immunostaining, the expression pattern of the TGF-beta type II receptor (TbetaRII) was first determined in the developing mouse lung. The functions of TbetaRII in developing lung were then determined by conditionally knocking out TbetaRII in the lung epithelium of floxed-TbetaRII/surfactant protein C-reverse tetracycline transactivator/TetO-Cre mice versus mesenchyme of floxed-TbetaRII/Dermo1-Cre mice. TbetaRII was expressed only in distal airway epithelium at early gestation (embryonic day (E)11.5), but in both airway epithelium and mesenchyme from mid-gestation (E14.5) to post-natal day 14. Abrogation of TbetaRII in mouse lung epithelium resulted in retardation of post-natal lung alveolarisation, with markedly decreased type I alveolar epithelial cells, while no abnormality in prenatal lung development was observed. In contrast, blockade of TbetaRII in mesoderm-derived tissues, including lung mesenchyme, resulted in mildly abnormal lung branching and reduced cell proliferation after mid-gestation, accompanied by multiple defects in other organs, including diaphragmatic hernia. The primary lung branching defect was verified in embryonic lung explant culture. The novel findings of the present study suggest that transforming growth factor-beta type II receptor-mediated transforming growth factor-beta signalling plays distinct roles in lung epithelium versus mesenchyme to differentially control specific stages of lung development.


Assuntos
Epitélio/metabolismo , Regulação Enzimológica da Expressão Gênica , Pulmão/embriologia , Mesoderma/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Mucosa Respiratória/metabolismo , Animais , Apoptose , Proliferação de Células , Células Epiteliais/metabolismo , Pulmão/metabolismo , Camundongos , Camundongos Knockout , Modelos Biológicos , Receptor do Fator de Crescimento Transformador beta Tipo II , Transdução de Sinais , Fatores de Tempo
4.
Plant Biol (Stuttg) ; 19(2): 286-297, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27775866

RESUMO

Carrot is generally regarded as a biennial plant with an obligatory vernalization requirement. Early spring cultivation makes plants vulnerable to premature bolting, which results in a loss of commercial value. However, our knowledge of flowering time genes and flowering mechanisms in carrot remain limited. Bolting behavior of D. carota ssp. carota 'Songzi', a wild species sensitive to flower induction by vernalization and photoperiod, and orange cultivar 'Amsterdam forcing', and their offspring were investigated in different growing conditions. We performed RNA-seq to identify the flowering time genes, and digital gene expression (DGE) analysis to examine their expression levels. The circadian patterns of related genes were identified by qPCR. The results showed bolting behavior of carrot was influenced by low temperature, illumination intensity and photoperiod. A total of 45 flowering time-related unigenes were identified, which were classified into five categories including photoperiod, vernalization, autonomous and gibberellin pathway, and floral integrators. Homologs of LATE ELONGATED HYPOCOTYL (LHY) and CONSTANS-LIKE 2 (COL2) were more highly expressed under short day condition than under long day condition. Homologs of COL2, CONSTANS-LIKE 5 (COL5), SUPPRESSION OF OVEREXPRESSION OF CONSTANS 1 (SOC1), FLOWERING LOCUS C (FLC) and GIBBERELLIC ACID INSENSITIVE (GAI) were differentially expressed between 'Songzi' and 'Amsterdam forcing'. The homolog of COL2 (Dct43207) was repressed by light, but that of COL5 (Dct20940) was induced. A preliminary model of genetic network controlling flowering time was constructed by associating the results of DGE analysis with correlation coefficients between genes. This study provides useful information for further investigating the genetic mechanism of flowering in carrot.


Assuntos
Daucus carota/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Fotoperíodo , Transcriptoma , Relógios Circadianos , Daucus carota/crescimento & desenvolvimento , Daucus carota/fisiologia , Daucus carota/efeitos da radiação , Flores/genética , Flores/crescimento & desenvolvimento , Flores/fisiologia , Flores/efeitos da radiação , Perfilação da Expressão Gênica , Luz , Filogenia , Fatores de Tempo
5.
J Am Coll Cardiol ; 29(6): 1246-55, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9137220

RESUMO

OBJECTIVES: The aim of this study was to assess the effects of ischemia on diastolic function by analyzing flow propagation velocity with color M-mode Doppler echocardigraphy. BACKGROUND: Color M-mode Doppler echocardiography has been proposed as a method of assessing left ventricular filling. METHODS: Color M-mode Doppler echocardiography and measurement of hemodynamic data were performed simultaneously at baseline and during angioplasty-induced ischemia. Tau was compared with flow propagation velocity. Late diastolic indexes, left ventricular pressure and flow cessation time were also investigated. RESULTS: During ischemia, left ventricular relaxation rate (tau) increased, whereas flow propagation velocity decreased, from (mean +/- SD) 46.8 +/- 10 ms to 72.6 +/- 18.3 ms and from 59.8 +/- 15.8 cm/s to 30 +/- 8 cm/s, respectively (all p < 0.0001). The maximal slowing of flow propagation velocity was observed 20 to 30 s after the beginning of the inflation, coexisting with a notch on the ascending limb of the negative rate of rise of the left ventricular pressure (dP/dt) curve. Flow propagation velocity was correlated with tau both at baseline (r = 0.53, p < 0.05) and during inflation (r = 0.53, p < 0.03). Left ventricular end-diastolic pressure increased during ischemia from 13.5 +/- 8 mm Hg at baseline to 27.5 +/- 7 mm Hg, while a premature cessation of the entering flow occurred -13.8 +/- 23 ms before the next Q wave onset, compared with 4.5 +/- 19.6 ms after the Q wave onset at baseline (all p < 0.0001). CONCLUSIONS: The analysis of flow propagation velocity showed that early filling is highly dependent on left ventricular relaxation rate, particularly through the phenomenon of asynchrony. During ischemia, the premature cessation of late filling is associated with increased diastolic pressures.


Assuntos
Angioplastia Coronária com Balão , Diástole/fisiologia , Ecocardiografia Doppler em Cores , Isquemia Miocárdica/diagnóstico por imagem , Isquemia Miocárdica/fisiopatologia , Função Ventricular Esquerda/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Cateterismo Cardíaco , Circulação Coronária/fisiologia , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/fisiopatologia , Doença das Coronárias/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Processamento de Sinais Assistido por Computador , Volume Sistólico/fisiologia , Fatores de Tempo
6.
Dig Liver Dis ; 34(10): 707-16, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12469798

RESUMO

BACKGROUND: Biomechanical properties in terms of residual strains in diabetic small intestine have not been studied. Furthermore, no data have been reported on affect of gliclazide on gastrointestinal complications of diabetes. AIMS: To determine remodelling of zero-stress state of small intestine in streptozotocin-induced diabetic rats and effect of gliclazide treatment. MATERIALS: Morphological properties and residual strains were studied in duodenum, jejunum and ileum obtained from diabetic rats, gliclazide-treated diabetic rats and normal rats (n = 8 each group). METHODS: Diabetes was induced by single intraperitoneal injection of 65 mg/kg streptozotocin. Gliclazide (10 mg kg(-1) day(-1) was injected directly into stomach lumen by intragastric gavage twice daily. Experimental period was 35 days. To approach no-load state; intestinal segments were surgically excised and cut transversely into short ring-shaped segments. Each ring was cut radially to obtain geometry of zero-stress state. Circumferential length, the wall thickness and opening angle were measured from digital images of each specimen and residual strains were computed. RESULTS: Blood glucose level of diabetic group (approximately 20 mmol/l) was consistently higher than that in normal group (approximately 4 mmol/l) after induction of diabetes (p < 0.001). Gliclazide lowered average blood glucose level to between 10 and 15 mmol/l (p < 0.001). Plasma insulin levels of both diabetic groups (average between 10 and 15 pmol/l) were significantly lower than those in normal group (average approximately 18 pmol/l, p < 0.05). Wet weight per unit length and wall thickness of duodenum, jejunum and ileum were significantly higher in Diabetes group than those in Normal group (p < 0.05). Opening angle and absolute value of residual strain were significantly smaller in duodenum and larger in jejunum and ileum in Diabetes group than in Normal group (p < 0.001). Gliclazide treatment partly restored these changes (p < 0.05). CONCLUSIONS: Diabetes induced morphometric and biomechanical remodelling in intestine. Gliclazide partly restored these changes.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Gliclazida/farmacologia , Hipoglicemiantes/farmacologia , Intestino Delgado/efeitos dos fármacos , Animais , Diabetes Mellitus Experimental/fisiopatologia , Intestino Delgado/fisiopatologia , Masculino , Ratos , Ratos Wistar
7.
Vet Microbiol ; 87(3): 193-203, 2002 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-12052330

RESUMO

Twelve Newcastle disease virus (NDV) strains were isolated from chickens involved in outbreaks of Newcastle disease (ND) in western China (Shaanxi, Gansu, Xinjiang, Qinghai and Guangxi provinces) between 1979 and 1999. All strains were determined to be velogenic by plaque formation, the mean death time (MDT) of embryonated eggs, and the intracerebral pathogenicity index (ICPI). For preparation of virus RNA, the acid guanidinium-thiocyanate method was used. A 908bp fragment of nucleotide was amplified by RT-PCR starting from the N terminal of the F gene and the PCR segments were cloned into the PGEM-T vector and sequenced. The similarities of the nucleotide sequences (1-519bp) and predicted amino acid sequences of the F gene (1-125) were analyzed by comparing the 12 NDV isolates with the NDV vaccine strains Lasota, B1, H1 and V4, with classical NDV strains and recent epizootic strains. Phylogenetic analysis demonstrated that all strains were of two novel genotypes; the NDV strains that caused the outbreak of ND in western China during 1998-1999 was of the genotype VIIa, whereas the strains from the Qinghai province (1979-1985) were of genotype VIII, which has been found predominately in southern Africa.


Assuntos
Galinhas , Surtos de Doenças/veterinária , Doença de Newcastle/epidemiologia , Vírus da Doença de Newcastle/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Embrião de Galinha , China/epidemiologia , DNA Complementar/química , DNA Complementar/genética , Dados de Sequência Molecular , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/isolamento & purificação , Proteínas do Nucleocapsídeo , Nucleoproteínas/química , Nucleoproteínas/genética , Filogenia , RNA Viral/química , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Homologia de Sequência de Aminoácidos , Organismos Livres de Patógenos Específicos , Proteínas Virais/química , Proteínas Virais/genética
8.
J Biochem Biophys Methods ; 52(3): 169-78, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12376020

RESUMO

To overcome the drawbacks of encapsulating plasmid DNA (pDNA) in poly (D,L-lactic-co-glycolic acid) (PLGA) by water-in-oil-in-water double-emulsion solvent-evaporation method, we have developed a novel procedure for encapsulating pDNA in PLGA microparticles called DNA organic phase self-emulsification (DOPSM). This method was based on both the extraction plasmid DNA from aqueous phase into organic phase and the spontaneous emulsification DNA in organic phase by solvent diffusion method. The efficiency of extraction plasmid DNA into organic phase is 99% and the concentration of pDNA in organic phase is up to 2.4 mg/ml. The efficiency of microencapsulation of plasmid DNA in PLGA is up to 76% and can be enhanced by lowering the pH of aqueous solution of emulsion. The microparticles size of PLGA of pDNA is in a narrow range of 1-2 microm. This procedure does not involve the high mechanical energy to emulsify which may damage the integrity of pDNA. This method can be applied to encapsulate the pDNA into microparticles of other biocompatible polymers with high efficiency.


Assuntos
Materiais Revestidos Biocompatíveis/química , Sistemas de Liberação de Medicamentos/instrumentação , Ácido Láctico/química , Plasmídeos/administração & dosagem , Plasmídeos/química , Ácido Poliglicólico/química , Polímeros/química , Emulsões/química , Microesferas , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Controle de Qualidade
9.
In Vivo ; 13(1): 29-34, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10218129

RESUMO

The effects of ligustrazine on hepatic oxygenation in the isolated rat liver were investigated during prolonged perfusion and following the injection of norepinephrine. After injection of erythrocytes into the perfusate, the hemoglobin spectra in the liver were measured by Erlangen microlightguide spectroscopy, and the hemoglobin oxygenation (HbO2) in the liver was calculated on the basis of the Kubelka-Munk theory. During artificial perfusion, the HbO2 value was decreased from 59.3 +/- 6.4% (after one hour's perfusion) to 25.5 +/- 19.5% (n = 441; after six hours' perfusion). However, when ligustrazine was injected into the perfusate after six hours' perfusion, the HbO2 values recovered to 56.4 +/- 9.7% (n = 441). After injection of norepinephrine, HbO2 in the liver decreased from 48.8 +/- 10.4% to 25.2 +/- 18.4% (n = 961), while subsequent administration of ligustrazine caused a recovery to 62.9 +/- 6.0% (n = 961). Our results suggested that ligustrazine is a powerful hepatic vasodilator for improving hepatic oxygenation.


Assuntos
Fígado/efeitos dos fármacos , Pirazinas/farmacologia , Vasodilatadores/farmacologia , Animais , Técnicas In Vitro , Injeções , Fígado/fisiologia , Masculino , Norepinefrina/farmacologia , Oxigênio , Perfusão , Ratos , Ratos Wistar , Fatores de Tempo , Vasoconstritores/farmacologia
10.
Sci Total Environ ; 199(1-2): 111-4, 1997 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-9200853

RESUMO

In an area of China, not previously studied in detail concerning cadmium pollution and possible adverse effects on the kidney of exposed populations, concentrations of cadmium in urine as an indicator of renal accumulation of cadmium was studied and related to indicators of renal dysfunction in order to examine if a relationship could be documented. Cadmium concentrations in urine were analysed by graphite furnace atomic absorption spectrometry and urinary beta-2 microglobulin (UBM) and albumin (UALB) were measured as indicators of renal dysfunction, Rice samples and urine samples were obtained from three areas in Zhejiang province, China, representing a highly exposed area, a medium exposed area and a control area, respectively. Cadmium concentrations in rice were 3.70, 0.51 and 0.072 mg/kg for the heavily, medium polluted areas and the control area, respectively. Cadmium concentrations in urine (geometric means) were 10.7, 1.62 and 0.40 micrograms/l in the high, medium and control areas respectively. There was a clear increase in UBM and UALB in the heavily exposed group in comparison to the control group and a slight increase in the medium exposed group. There was a statistically significant dose-response relationship between cadmium in urine and beta 2-microglobulin excretion in urine, which is similar to what has previously been reported in other countries. The findings constitute the first report concerning a dose-response relationship in this population group in Zhejiang province in China.


Assuntos
Cádmio/urina , Exposição Ambiental , Monitoramento Ambiental , Rim/efeitos dos fármacos , Microglobulina beta-2/urina , Adulto , Albuminúria , Cádmio/efeitos adversos , China , Estudos de Coortes , Relação Dose-Resposta a Droga , Monitoramento Ambiental/métodos , Poluentes Ambientais/efeitos adversos , Poluentes Ambientais/análise , Feminino , Análise de Alimentos , Contaminação de Alimentos , Humanos , Rim/metabolismo , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Oryza/química , Espectrofotometria Atômica
11.
J Pediatr Surg ; 22(5): 439-42, 1987 May.
Artigo em Inglês | MEDLINE | ID: mdl-3585667

RESUMO

The approach of the combined traditional Chinese and modern medicinal treatment of Hirschsprung's disease has been applied in 90 cases. Long-term follow-up showed satisfactory results. Of these, 55 cases with a typical history, plus a positive ACHE and x-ray were selected for analysis and discussion, making an over all rate of 78.18%. This treatment is particularly useful for those babies under 1 year of age with a short narrow segment of the rectum. In addition, it would be a good trial procedure for those babies over 1 year old with mild symptoms and the narrow segment just beyond the sigmoidorectal junction.


Assuntos
Doença de Hirschsprung/terapia , Medicina Tradicional Chinesa , Medicina Tradicional do Leste Asiático , Terapia por Acupuntura , Trifosfato de Adenosina/uso terapêutico , Terapia Combinada , Dilatação , Feminino , Doença de Hirschsprung/tratamento farmacológico , Humanos , Lactente , Masculino
12.
Med Eng Phys ; 23(8): 557-66, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11719078

RESUMO

Luminal nutrients are essential for maintaining the structural and functional integrity of the gut. Starvation induces pronounced structural and biomechanical remodelling in the rat small intestine. The present work was done to study the recovery process after resumption of food intake. Twenty-five Wistar rats were allocated to five groups. Four groups fasted for 7 days but had free access to water. One of these groups served as fasted controls and was killed at the end of the fast. The other three groups were re-fed for 2, 4 and 7 days before they were euthanised. The fifth group had free access to food during the whole study (fed controls). The intestinal no-load state, zero-stress state and the stress-strain relationship during distension were studied. The intestinal segments were cut transversely into a series of short ring-shaped segments to obtain the no-load state. Each ring was cut in the radial direction to obtain the zero-stress state. The rats regained the lost body weight (22%) by the 7th day of re-feeding. The lost duodenal mass (40%) and jejunal mass (25%) were regained by the 2nd day whereas the lost mass from ileum (18%) was regained by the 4th day. The fasting-induced morphometric changes were normalised by re-feeding on the 2nd day in the duodenum and jejunum, and on the 4th day in the ileum. The longitudinal stress-strain curves shifted to the right after fasting and shifted back within two days following re-feeding (P<0.05). The circumferential stress-strain curves in the fasted or re-fed rats changed in a similar though less pronounced way. Normal values were reached within 4-7 days for the circumferential direction. In conclusion, fasting-induced biomechanical and structural remodelling were normalised by re-feeding in a time- and location-dependent way.


Assuntos
Ingestão de Alimentos , Intestino Delgado/patologia , Inanição , Animais , Glicemia/metabolismo , Peso Corporal , Duodeno/patologia , Feminino , Intestino Delgado/metabolismo , Jejuno/patologia , Modelos Teóricos , Mucosa/metabolismo , Ratos , Ratos Wistar , Estresse Mecânico , Fatores de Tempo , Aumento de Peso , Redução de Peso
13.
Biorheology ; 37(5-6): 385-400, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11204544

RESUMO

Morphometric and passive biomechanical properties were studied in isolated segments of the thoracic and abdominal aorta, left common carotid artery, left femoral artery and the left pulmonary artery in 20 non-diabetic and 28 streptozotocin (STZ)-induced diabetic rats. The diabetic and non-diabetic rats were divided into groups living 1, 4, 8, and 12 weeks after the induction of diabetes (n = 7 for each diabetic group) or sham injection (n = 5 for each group). The mechanical test was performed as a distension experiment where the proximal end of the arterial segment was connected via a tube to the container used for applying pressures to the segment and the distal end was left free. The vessel diameter and length were obtained from digitized images of the arterial segments at pre-selected pressures and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data and from the zero-stress state data. The zero-stress state was obtained by cutting vessel rings radially causing the rings to open up into a sector. Diabetes was associated with pronounced morphometric changes, e.g., wall thickness. With respect to the biomechanical data, the opening angle increased and reached a plateau in 4 weeks after which it decreased again (p < 0.05). The opening angle was smallest in the thoracic aorta and largest in the pulmonary artery. Furthermore, it was found that the circumferential stiffness of the arteries studied increased with the duration of diabetes. In the longitudinal direction significant differences were found 8 weeks after injection of STZ in all arteries except the pulmonary artery. In the 12 weeks group, the femoral artery was stiffest in the circumferential direction whereas the thoracic aorta was stiffest in the longitudinal direction. The accumulated serum glucose level correlated with the arterial wall thickness and elastic modulus (correlation coefficient between 0.56 and 0.81).


Assuntos
Artérias/fisiopatologia , Diabetes Mellitus Experimental/fisiopatologia , Angiopatias Diabéticas/fisiopatologia , Animais , Artérias/patologia , Fenômenos Biomecânicos , Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Peso Corporal/fisiologia , Diabetes Mellitus Experimental/patologia , Angiopatias Diabéticas/patologia , Masculino , Ratos , Ratos Wistar , Estresse Mecânico
14.
Biorheology ; 25(3): 539-44, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3250634

RESUMO

Hartert's thromboelastography has been used in the diagnosis of abnormal blood clotting for more than 20 years. From a thromboelastogram three parameters are obtained, viz, the reaction time 'r', the rate of formation of fibrin clot 'k', the maximum elasticity of thrombus 'amax'. It is desirable, however, to know the equation that describes the thromboelastogram both in the period in which the complex modulus increases with time because of coagulation, and in the period in which the complex modulus decreases with time because of fibrinolysis. The parameters of the equation could then be used as a diagnostic criterion; yielding information on the mechanism of coagulation and fibrinolysis. Based on our experimental results on human blood in normal and abnormal subjects, we found that the complex modulus of thromboelastograms can be expressed by the sum of two terms, one describing the increase of the complex modulus during coagulation, G1 = G'1 Exp (-tau 1/t), the other describing the decrease of the complex modulus during fibrinolysis, G2 = G'2 Exp (-tau 2/(t-D) when t greater than D. G2 = 0 when t less than D. The compound complex modulus from coagulation to fibrinolysis is G = G1 - G2. Here t is the clotting time, and G'1, G'2, tau 1, tau 2, and D are five constants to be identified. These five constants can be used for diagnostic and prognostic purposes.


Assuntos
Coagulação Sanguínea , Fibrinólise , Tromboelastografia , Adulto , Feminino , Hemofilia A/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Gravidez , Púrpura Trombocitopênica/sangue
15.
Biorheology ; 40(1-3): 31-9, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12454384

RESUMO

Caveolin-1 is a principal component of caveolae and is involved in signaling transduction in a number of cells. A hypothesis was proposed in this work that mechanical forces due to flow induce caveolin-1 translocation. So the changes of caveolin-1 expression and distribution in cultured endothelial cells (HUVECs) exposed to a steady laminar flow were studied. For comparing with the influence of cytokine, caveolin-1 in the cells stimulated by TNF-alpha was also investigated. Indirect immunofluorescence and double fluorescence labeling showed that in control cells, caveolin-1 was primarily localized on the cell surface, which corresponded to the peripheral distribution of F-actin, and presented some local concentrations. In the cells exposed to a laminar flow (1.0 Pa), caveolin-1 distribution showed a time-dependent variation. After 24 h of shear, the local concentration of caveolin-1 was found, in the most cells, at upstream side of cell body. Also more caveolin-1 molecules were observed in the cells. In contrast, TNF-alpha induced a decrease of caveolin-1 in cells. The redistribution of caveolin-1 seems to be correlated to F-actin organization.


Assuntos
Caveolinas/metabolismo , Endotélio Vascular/metabolismo , Mecanotransdução Celular/fisiologia , Fator de Necrose Tumoral alfa/farmacologia , Actinas/metabolismo , Caveolina 1 , Técnicas de Cultura de Células , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Técnica Indireta de Fluorescência para Anticorpo , Hemorreologia , Humanos , Microscopia de Fluorescência , Estresse Mecânico
16.
Clin Hemorheol Microcirc ; 23(2-4): 191-5, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11321440

RESUMO

The present experiment attempted to evaluate the effect of electrical acupuncture on the cerebral microcirculation in anesthetized rats, using fluorescence videomicroscopy. Changes in the pial arteriolar diameter under acute hemorrhagic hypotension were examined quantitatively. The present results suggest that acupuncture may be effective in improving the cerebral microcirculation in hemorrhagic hypotension.


Assuntos
Circulação Cerebrovascular , Eletroacupuntura , Hipotensão/terapia , Pia-Máter/irrigação sanguínea , Choque Hemorrágico/terapia , Vasodilatação , Anestesia Geral , Animais , Arteríolas , Hipotensão/etiologia , Hipotensão/fisiopatologia , Masculino , Microcirculação , Microscopia de Fluorescência , Microscopia de Vídeo , Ratos , Ratos Wistar , Choque Hemorrágico/complicações , Choque Hemorrágico/fisiopatologia
17.
Clin Hemorheol Microcirc ; 21(3-4): 291-5, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10711757

RESUMO

The aim of this work is to study the deformability of red blood cells (RBC) by two laser diffraction methods: the Laser-assisted Optical Rotational Cell Analyser (LORCA, Mechatronics, Amsterdam, Netherlands) and a Shear Stress Diffractometer (RHEODYN SSD, Myrenne, Roetgen, Germany). Experiments were carried out on 46 healthy human subjects. The elongation index EI of normal and hardened RBCs (obtained by heating blood at 49 degrees C or by incubating RBCs in solutions of diamide) was measured. The results showed that the standard deviations of the experimental data for normal RBCs were relatively small, especially at high shear stresses (more than 3.0 Pa), but higher than those reported before. Some correlations between the results given by the two instruments were also found. It should be noted that for hardened RBCs, the standard deviations of the measurements were important compared with the mean values in the two instruments.


Assuntos
Deformação Eritrocítica/fisiologia , Lasers , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
18.
Clin Hemorheol Microcirc ; 23(1): 1-11, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11214708

RESUMO

The effect of laminar flow on the regulation of von Willebrand Factor (vWF) of cultured human umbilical vein endothelial cells (HUVECs) was studied. Confluent endothelial monolayers were exposed to shear stresses (0.2 and 1.0 Pa) from 2 to 24 h. vWF was labelled with indirect immunofluorescence method and observed with 3D fluorescence microscopy. The distribution of vWF and the cytoskeleton organization were observed simultaneously by double fluorescence labelling. More actin stress fibers and an increased release of vWF appeared in the cells exposed to flow at the same time. The qualitative and quantitative results showed that there was not only a shear-dependent regulation but also a time-dependent modification. For a short-time shear stimulation, both 0.2 Pa and 1.0 Pa shear stresses induced a release of vWF from the endothelial cells. In contrast, after 24 h exposure to 1.0 Pa shear flow, vWFs were much more in the cells than that in the cells exposed to 0.2 Pa for 24 h (p < 0.01) or that in the control cells (p < 0.05). TNF-alpha caused a decrease of vWF and Weibel-Palade bodies in the cells.


Assuntos
Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Fator de von Willebrand/metabolismo , Citoesqueleto de Actina/ultraestrutura , Células Cultivadas , Citoesqueleto/ultraestrutura , Ambiente Controlado , Imunofluorescência , Humanos , Imageamento Tridimensional , Microscopia de Fluorescência , Estresse Mecânico , Fatores de Tempo , Fator de Necrose Tumoral alfa/farmacologia , Veias Umbilicais/citologia , Corpos de Weibel-Palade/metabolismo
19.
Clin Hemorheol Microcirc ; 23(2-4): 145-51, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11321434

RESUMO

The aim of this work was to study the effects of tetramethylpyrazine (TMP) on the interaction between lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesive molecule-1 (ICAM-1) by micropipette technique. A pair of cells, i.e., a human lymphocyte or a S KW-3 cell (human T cell leukemia), LFA-1 was expressed on which cellular surfaces, and a RBC coupled with ICAM-1, were the carriers for LFA-1 and ICAM-1. The adhesion probabilities of this pair of cells were mediated by specific interactions between ICAM-1 and LFA-1. Phytohemagglutinin (PHA) stimulation resulted in the significant increase in the adhesion probability compared to the resting lymphocyte. TMP treatment can inhibit such increase and even make the adhesion probability lower than the resting state. While the LFA-1 expression has not changed significantly with PHA stimulation or with TMP treatment, which indicated that TMP inhibiting effects was realized by a possible conformation change.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Molécula 1 de Adesão Intercelular/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Antígeno-1 Associado à Função Linfocitária/metabolismo , Fito-Hemaglutininas/antagonistas & inibidores , Pirazinas/farmacologia , Linfócitos T/efeitos dos fármacos , Adulto , Adesão Celular/efeitos dos fármacos , Adesão Celular/genética , Deformação Eritrocítica , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Leucemia de Células T/patologia , Antígeno-1 Associado à Função Linfocitária/química , Masculino , Micromanipulação , Pessoa de Meia-Idade , Fito-Hemaglutininas/farmacologia , Ligação Proteica/efeitos dos fármacos , Conformação Proteica/efeitos dos fármacos , Relação Estrutura-Atividade , Linfócitos T/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo
20.
Clin Hemorheol Microcirc ; 17(4): 325-31, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9493901

RESUMO

In situ expression of ICAM-1 and ICAM-1 mRNA on the lung tissue of asthmatic rats was studied by immunohistochemical staining and in situ hybridization, respectively. The results showed that in normal rats ICAM-1 expression was rare on the endothelium of pulmonary artery and vein, and on the bronchial and alveolar epithelium. The distribution of ICAM-1 expression on the different part of lung tissue of asthmatic rats was similar to that of normal rats, but the level of ICAM-1 expression was significantly increased on the endothelium of pulmonary artery (EPA) and vein (EPV), bronchial epithelium (BEP) and alveolar epithelium (AEP) compared with those of normal and sensitized controls. The distribution and expression of ICAM-1 mRNA on the different part of lung tissue of normal and asthmatic rats were similar to that of ICAM-1 expression. In asthmatic rats, the expression of ICAM-1 mRNA on AEP and EPV was increased significantly compared with those of normal and sensitized controls. It is concluded that the increase of ICAM-1 expression on endothelium of pulmonary vessels, epithelium of broncheoli and alveoli may play an important role of inflammatory cell infiltration in asthmatic rats, and the increased expression of ICAM-1 in asthmatic rats was caused by the increase of expression of ICAM-1 mRNA.


Assuntos
Asma/genética , Asma/metabolismo , Hibridização In Situ , Molécula 1 de Adesão Intercelular/biossíntese , Pneumopatias Obstrutivas/genética , Pneumopatias Obstrutivas/metabolismo , Pulmão/química , Pulmão/citologia , RNA Mensageiro/biossíntese , Animais , Brônquios/química , Brônquios/citologia , Líquido da Lavagem Broncoalveolar/citologia , Endotélio Vascular/química , Endotélio Vascular/citologia , Células Epiteliais/química , Molécula 1 de Adesão Intercelular/análise , Molécula 1 de Adesão Intercelular/genética , Contagem de Leucócitos , Alvéolos Pulmonares/química , Alvéolos Pulmonares/citologia , RNA Mensageiro/análise , Ratos , Ratos Wistar
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA