It has been suggested that melatonin is involved in learning and memory. In the present study, we investigated the effects of melatonin on spatial learning and memory in rats, using Morris water maze and electrophysiological methods. The results are as follows. (1) During a six-day water maze training, the mean escape latency of melatonin group in the last 4 days was 30.02+/-3.6 s, and that of control group was 18.44+/-2.7 s (P<0.01). The crossing annulus coefficient of melatonin group was 25.68+/-2.32%, and that of control group was 43.33+/-2.85% (P<0.01). (2) Microinjection of melatonin into CA1 area inhibited long-term potentiation (LTP). Sixty minutes after tetanus, the field excitory postsynaptic potentials (fEPSP) slope of group C (n=7 0.5 microliter saline) was 169.71+/-6.48 % of the baseline, and that of group M2 (n=6, 2 microgram melatonin) was 114.28+/-1.80% of the baseline. The difference is significant (P<0.01). (3) We also investigated the effects of melatonin on LTP after administration of scopolamine. Sixty minutes after tetanus, the fEPSP slope of group SM (n=6, 2 microgram scopolamine before 2 microgram melatonin) was 113.70+/-5.55% of the baseline. It showed a significant decrease compared with group C (P<0.01). However, there was no difference between groups SM and M2 (P>0.05, i.v.). The results obtained by applying melatonin after bicuculline were different from those after scopolamine. Sixty minutes after tetanus, the fEPSP slope of group BM (n=7, 1 microgram bicuculline before 2 microgram melatonin) was 162.29+/>10.52% of the baseline. Compared with group C, there is no significant difference (P>0.05); but compared with group M2, the difference is significant (P<0.01). Our results showed that application of melatonin in rats significantly inhibited not only spatial learning and memory, but also LTP in CA1 area. Furthermore, the results indicate that the inhibition of LTP by melatonin may not be mediated by cholinergic system, but may be through the modulation of GABAergic system.
Animals ; Bicuculline ; pharmacology ; Female ; Hippocampus ; drug effects ; physiology ; Learning ; drug effects ; Long-Term Potentiation ; drug effects ; Male ; Melatonin ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Scopolamine Hydrobromide ; pharmacology ; Space Perception ; drug effects

OBJECTIVETo study the effects of insulin on the proteolysis of cultured rabbit skeletal muscular myotubes in vitro, and their possible mechanisms.

METHODSMuscles of lower limbs of juvenile rabbits were isolated for tissue-block culture. After passage, myoblasts were formed and fused into myotubes. Then the protein in myotubes was radiolabelled with L-[ 3,5-3H] tyrosine. The myotubes were cultured in DMEM medium containing 100 nmol/L insulin (n = 24, group B) , 100 nmol/L dexamethasone (n = 24, group C) , 100 nmol/L insulin and 100 nmol/L dexamethasone (n = 24, group D) , no insulin or dexamethasone (n =24, group A), respectively. Twenty-four hours after culture, the L-[3,5-3H] tyrosine content in culture medium and cells were determined, and the degradation rates of protein were calculated. The mRNA expressions of ubiquitin and protease C2 subunit were determined by Northern blot.

RESULTSThe degradation rates of myotube protein in group A(0. 38+/-0.04) was obviously lower than that in group C (0.50+/-0.03, P <0.01), but it was obviously higher than that in group B(0. 35+/-0.03, P <0.05). Though the degradation rates of myotube protein in group D (0.41+/-0. 03) was evidently lower than that in group C ( P < 0.01) , it was still higher than that in group A( P < 0.05 ). The mRNA expressions of ubiquitin and protease C2 subunit in group A ( the scale: 2. 4 kb ubiquitin was 0. 82+/-0. 15, 1. 2 kb ubiquitin was 0. 60+/-0. 10, C2 subunit was 0. 75+/-0. 16) was obviously lower than that in group C ( the scale: 2.4 kb ubiquitin was 2. 15+/-0. 23, 1.2 kb ubiquitin was 1.50+/-0. 14,C2 subunit was 1.50+/-0. 13 , P <0. 01) , but it in group D was lower than that in group C (the scale: 2. 4 kb ubiquitin was 1. 25+/-0. 17, 1. 2 kb ubiquitin was 0. 85+/-0. 09, C2 subunit was 0. 90+/-0. 15, P <0. 01) , and it was similar to that in group B (the scale: 2.4 kb ubiquitin was 0. 85+/-0.07, 1.2 kb ubiquitin was 0. 65+/- 0. 12, C2 subunit was 0. 76 +/-0. 09, P > 0. 05).

CONCLUSIONThe effects of insulin on the activity of ubiquitin-proteasome pathway and the proteolytic rate in normal myotubes were relatively weak. However, insulin can significantly inhibit the effects of dexamethasone on the gene expressions of ubiquitin system and the proteolytic rate in myotubes, but the mechanism needs further research.

Animals ; Cells, Cultured ; In Vitro Techniques ; Insulin ; pharmacology ; Male ; Muscle Fibers, Skeletal ; drug effects ; metabolism ; Muscle Proteins ; metabolism ; Rabbits ; Ubiquitin ; metabolism

OBJECTIVETo study neuro-protective effect of naomaitong on brain damage after focal cerebral ischemia reperfusion (I/R) in the aged rats.

METHOD11 groups of 20-22-month old SD rats were subjected to 3 hours of middle cerebral artery occlusion with the intraluminal filament technique, followed by 12 hours of reperfusion. Nervous symptom, oedema of brain, infarct size, morphology and superfine structure of brain, etc were monitored thoughout cerebral ischemia and reperfusion.

RESULTInfarct size of brain in ischemia and reperfusion groups were significantly greater. Oedema of it was higher, nervous symptom of it was more serious, and morphology and superfine structure brain were more obvious than those of sham-operated group. Nervous symptom, oedema of brain, infarct size, morphology and superfine structure of brain in treated groups were ligher than those of untreated groups (P < 0.001).

CONCLUSIONNaomaitong can protect brain damage after focal cerebral I/R in the aged rats.

Age Factors ; Animals ; Behavior, Animal ; drug effects ; Brain ; pathology ; Brain Ischemia ; complications ; Drug Combinations ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Male ; Neuroprotective Agents ; pharmacology ; Panax ; chemistry ; Plants, Medicinal ; chemistry ; Pueraria ; chemistry ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; pathology ; physiopathology ; Rheum ; chemistry

OBJECTIVEElectron microscopical study of infected cells to identify the pathogenic agent of SARS.

METHODSVero E6 cells infected with lung autopsy samples or nasopharyngeal swabs from SARS patients of Beijing and Guangzhou were inoculated. The supernatant and cultured cells exhibiting identifiable cytopathic effect (CPE) were prepared for electron microscopic study.

RESULTSExamination of CPE cells on thin-section revealed characteristic coronavirus particles within the cisternae of endoplasmic reticulum, Golgi apparatus, vesicles and extracellular space. They were mainly spherical or oval in shape, annular or dense, about 80 nm in diameter. Negative-stain electron microscopy identified coronavirus particles in culture supernatant, 80 - 120 nm in diameter, with club-shaped surface projections. Elongated, rod-, kidney- or other irregular shaped virons with the size of 100 - 200 nm by 60 - 90 nm were also found in the cultured cells infected with the lung samples from the Guangdong patients. Infectious virons entered cells by endocytosis or membrane fusion and released through a budding process.

CONCLUSIONThese data indicate a novel coronavirus as the causative agent of SARS. Most viral particles showed typical characteristics of coronavirus. The potential role of special shape viruses is expected to be further investigated.

Animals ; Cercopithecus aethiops ; Humans ; Microscopy, Electron ; SARS Virus ; ultrastructure ; Severe Acute Respiratory Syndrome ; virology ; Vero Cells

Objective To provide scientific evidence for prevention and control program on dengue fever through analyzing the situation of dengue fever in China,from 2005 to 2007.Methods Data was collected from Internet-based National Notifiable Infectious Disease Reporting System,National Enhanced Dengue Fever Surveillance system and field investigation on dengue outbreaks,described and analyzed with descriptively and by SPSS statistical software.Results There was a total number of 1 623 dengue cases(including 1356 laboratory confirmed cases and 267 probable cases)and 1 death case reported in China from 2005 to 2007.Among the identified cases,151 were imported from foreign countries as the Southeast Asian countries,accounting for 9.3%,while the rest 1472 cases were reported from local infections,identified only in 9 cities from Guangdong and Fujian provinces.Data from the monitoring program on Aedes Mosquitoes indicated that:The indicators of BI from 84.6% of the sentinels were over 5,and BI from 72.2% of the sentinels were over 10.This index was especially at a higher level during summer in the southern areas of China.Aedes albopictus was found in all the sentinel sites while Aedes aegypti was only found in Hainan and in limited counties of Guangdong.No dengue virus was isolated from mosquito vectors collected from national sentinel sites, whereas positive results had been detected by PCR test in Guangdong province.Conclusion It was assumed that a sustainable local circulation of dengue virus had not yet been established successfully in Mainland China according to the surveillance data.However,more local outbreaks reported in Guangdong and Fujian with the wide distribution and high-level density of aedes mosquito,low antibody level in healthy population and the increasing number of imported dengue cases, there is a potential of Dengue outbreaks in southera China.An integrated mosquito vector monitoring and management system is needed in hish risk area to reduce the transmission of dengue fever.

Objective To analyze the surveillance data on hemorrhagic fever with renal syndrome (HFRS) including the epidemiological characteristics and trend of the disease,in 2010.Methods Descriptive methods were conducted to analyze the surveillance data in 2010 which were collected from the internet-based National Notifiable Disease Reporting System and 40 HFRS sentinels in China.Results There were 9526 cases of HFRS reported in 2010 in the country with an annual morbidity of 0.71/105,which was higher than that reported in 2009.And the case fatality rate in 2010 was 1.24％.During the year 2010,most cases were reported in spring and autumn-winter season,with November as the peak month.The proportion of cases reported in autumn-winter season was higher than that in spring.The number of cases reported in males was higher than that in females among all the age groups,and similar pattern of mortality could be seen in most of the age groups.The percentage of cases over 60 years old had increased in recent years.Farmers were still under the highest risk.Density and the virus-carrying rate of animal hosts,as well as the infection rate were relatively stable and similar to the previous findings.As to the prevailing species,Apodemus agrarius and Rattus norvegicus were still the most common and leading animal hosts.However,the dominant species in sentinel of Yunnan were Rattus flavipectus and Eothenomys miletus respectively,and a new hantavirus called LUXV was found,namely Eothenomys miletus.Conclusion HFRS cases were widely distributed in most provinces of China,but cases mainly focus on certain areas and present the nature of aggregation.The risk of outbreak could not be ruled out for variety of factors.Population characteristics and seasonal fluctuation had been changing.

To investigate the non-viral vector mediating human coagulation factor VIII gene expression in mouse 32D cell line, a recombinant plasmid vector, pRC/RSV-hFVIIIBDcDNA, was constructed by cloning B-domain-deleted (Delta760aa-1639aa) human factor VIII cDNA (hFVIIIBDcDNA) into plasmid vector, pRC/RSV. The plasmid RC/RSV-hFVIIIBDcDNA was then transfected by means of SuperFect Transfection Reagent into mouse 32D cell line. After screening with G418, the procoagulant activity (hFVIII:C) and antigen (hFVIII:Ag) of human factor VIII in the culture medium were detected using one-stage method and ELISA, respectively. Furthermore, RT-PCR was performed to observe the transcription of hFVIIIBDcDNA. The results showed that human coagulation factor VIII protein existed in culture medium with hFVIII:C up to 2.01 U/(10(6) cell x 24 hours) and hFVIII:Ag to 450.08 ng/(10(6) cell x 24 hours). RT-PCR displayed mRNA of hFVIIIBDcDNA in 32D cells. It is concluded that the recombinant plasmid RC/RSV-hFVIIIBDcDNA can successfully express human FVIII in mouse 32D cell line, and hFVIII expressed in vitro presents the similar coagulant activity to the native hFVIII existing in normal human plasma.
Animals ; Cell Line ; DNA, Complementary ; genetics ; Enzyme-Linked Immunosorbent Assay ; Factor VIII ; genetics ; metabolism ; Gene Expression Regulation ; Humans ; Mice ; Plasmids ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

OBJECTIVETo investigate the effect of betulinic acid (BA) on relaxation in isolated rat aortic rings and its antioxidant property on oxidative stress of blood vessels.

METHODSAortic rings were isolated and BA was cumulatively added into organ bath. Isometric tension of endothelium intact or endothelium denuded thoracic aortic rings previously contracted by phenylephrine (PE) was recorded. Then aortic rings were randomly divided into normal control group, BA control group, H(2)O(2) group and BA+H(2)O(2) group, after being previously contracted by PE, isometric tension of endothelium-dependent relaxation induced by Ach was recorded.

RESULTExposure of intact endothelium rings previously contracted by PE to BA at the concentrations of 10(-7) mol/L-10(-4) mol/L evoked a significant concentration dependent relaxation, which was inhibited by pretreatment with N omega-nitro-L-arginine methyl ester (L-NAME, 10(-4)mol/L), but not by indometacin (10(-5)mol/L). The pD2 value of BA was 5.24 ± 0.04, and the EC(50)value was 2.45 x 10(-6)mol/L. Exposure of endothelium denuded rings previously contracted by PE to BA did not affect the relaxation in isolated aortic rings. ACh induced a dose-dependent relaxation that was weakened by pretreatment with H(2)O(2) (5 10(-4) mol/L) for 15 min. The EC(50) of BA markedly attenuated the inhibition of relaxation induced by H(2)O(2).

CONCLUSIONBA can evoke a concentration-dependent relaxation in aortic rings previously contracted by PE, which may be mediated by NO. And the decrease of endothelium-dependent relaxation in rat aortic rings exposed to H(2)O(2) can be markedly attenuated by BA, which may be mediated by reducing oxidative stress and maintaining the activity of NO in aortic rings.

Animals ; Aorta ; drug effects ; metabolism ; physiology ; Endothelium, Vascular ; drug effects ; metabolism ; physiology ; Hydrogen Peroxide ; pharmacology ; In Vitro Techniques ; Nitric Oxide ; metabolism ; Oxidative Stress ; drug effects ; Rats ; Rats, Sprague-Dawley ; Triterpenes ; pharmacology ; Vasodilation ; drug effects ; Vasodilator Agents ; pharmacology

OBJECTIVETo investigate the gene mutations in a pedigree with inherited prothrombin (FII) deficiency.

METHODSThe activated partial thromboplastin time (APTT), prothrombin time (PT), FII activity (FII:C) and FII antigen (FII:Ag) test were used for phenotype diagnosis. The genomic DNA was extracted from the peripheral blood of the propositus. All the 14 exons, intron/exon boundaries and the 5' and 3' untranslated regions (UTR) of the prothrombin gene were amplified by polymerase chain reaction (PCR). The PCR products were screened by direct sequencing and the mutations detected were further confirmed by restricted enzyme digestion. One hundred and three healthy blood donors were used as controls.

RESULTSThe phenotype of the propositus was prothrombin deficiency (type I). With reference to the prothrombin nucleotide sequence published by Degen & Dacie, three variations were found in the FII gene of the propositus. Among them, the novel mutation was a homozygous A601G subtitution in exon 2.

CONCLUSIONThe prothrombin deficiency of the propositus is caused by a homozygous Glu29 to Gly mutation in the prothrombin gene.

Blood Coagulation ; Child ; Female ; Humans ; Hypoprothrombinemias ; blood ; genetics ; Point Mutation ; Prothrombin ; genetics

OBJECTIVETo explore the gene mutation type of an inherited coagulation factor VII deficiency pedigree.

METHODSFVII:Ag, FVII:C, FVIIa were detected to classify deficiency type. FVII gene mutations were analysed in the proband and her family members by DNA directly sequencing. Biostructural pathology of the identified mutation was analysed by molecular modeling.

RESULTSHomozygosity of C-->T transition at position 11514 in exon 8 resulting in Thr359Met was identified in the proband, and heterozygosity for Thr359Met was confirmed in her parents, her son and some other family members. Thr359Met induces CRM-deficiency. It is found by computer simulated molecular model that the replacement of Thr by Met which has a larger and longer side chain might cause steric hindrance, and change the number of H-bonds.

CONCLUSIONSHomozygous missense mutation Thr359Met was found in a pedigree of hereditary FVII deficiency. This mutation might change the configuration of protein molecule and result in severe FVII deficiency.

Adolescent ; Adult ; Aged ; DNA Mutational Analysis ; Factor VII ; genetics ; Factor VII Deficiency ; genetics ; Female ; Homozygote ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Pedigree ; Polymerase Chain Reaction