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Biomedical subjects

Y Ji

Publications and source records attributed to Y Ji.

160 records · Page 9Linked to original sources
PubMed1991

[The in vitro induction of antibody responses of human lymphocytes and its application to hybridoma production].

Sources of immunized lymphocytes constitute one of the main obstacles in the production of human monoclonal antibodies. We tried to get them through in vitro immunization. Cells from excised tonsils or trauma spleens were used for the induction of antibody responses in vitro. Antibodies to different antigens including sheep red blood cells, ovalbumin, tetanus toxoid, and hepatitis B surface antigens were induced in 7-14 days' cultures. Taking tetanus toxoid as antigen, we analysed the various factors required for antibody induction with statistics analysis, which included cell separation method, T cell conditioned medium, antigen dosage, serum content, and concentration of mitogen PWM and LPS. The results showed: (1) The cell separation method influenced the antibody production significantly in comparison with other factors. It signified that immune cells' combination was the most influential factor. (2) Serum also constituted quite important influencing factor especially in the later period of culture. However, it did not make much differences if it attended 10% or so. The antigens and mitogens tended to be used at low concentration. (3) Due to the significant variation among individuals and among different antigens, it is suggested to set up the culture system with some flexibility so as to adapt to the variation in cells and antigens from different sources. The present culture system we use includes nylon wall column separation of cells, suitable range of antigens (three doses instead of one), and either 10% T cell conditioned medium or a mixture of 1 microgram PWM/ ml + 0.1 microgram LPS/ml. The human B lymphocytes stimulated in vitro with tetanus toxoid were used for the construction of human hybridomas.

Animals↗
PubMed1991

[Effect of liuwei dihuang decoction and its compatible prescriptions on lipid peroxide and lipofuscin].

Our experiment has shown that liuwei dihuang Decoction can decrease the contents of lipid peroxide in the serum as well as lipofuscin in the liver of the older mice to the level of the younger ones, while the two compatible prescriptions derived from the decoction, "Three invigorators" and "Three purges", cannot produce the same effect. All the three forms of prescription have no action on the lipofuscin in the heart.

Aging↗
PubMed1990

Dynamics of the distribution of cyclic AMP-dependent protein kinase in living cells.

The intracellular distribution of regulatory molecules may provide a mechanism for controlling gene expression. The subcellular location of cAMP-dependent protein kinase was analyzed in living cells by microinjection of regulatory and catalytic subunits labeled with fluorescein. Following microinjection, type I holoenzyme was found in the cytoplasm and remained there for up to 4 hr. Upon dissociation of holoenzyme with 8-bromo-cAMP, free catalytic subunit appeared in the nucleus while regulatory subunit remained in the cytoplasm. Similarly, purified catalytic subunit was transported to the nucleus in the absence of elevated intracellular cAMP following its introduction into the cytoplasm. Translocation to the nucleus was apparent within 10 min and persisted for at least 2 hr. In contrast, purified regulatory subunit, like holoenzyme, was maintained in the cytoplasm. These results suggest that one function of the type I regulatory subunit is to serve as a cytoplasmic anchor, sequestering the catalytic subunit in the cytoplasm until holoenzyme dissociates in response to increased cAMP.

Animals↗
PubMedDate not supplied

Scorpion BmK venom induces nociceptive response of rats by plantar injection.

In this study, the nociceptive responses induced by subcutaneous injection of scorpion BmK venom into the plantar surface of rat hind paw were quantified. The suitable dose of the venom is between 0.01 and 0.05 mg. The venom injection could induce local edema and tonic-pain responses, which had lasted more than 1 h. The pain scores reached peak intensity within 20 min, and then decreased slowly. Morphine, as a classic analgesic drug, could inhibit the spontaneous nociceptive response induced by the venom. With Morphine pretreatment, the mean pain scores for the entire 60 min were significantly decreased (P<.05). BmK I, a main lethal component, was also found to induce nociceptive responses with dose-dependent means. The nociceptive responses induced by BmK I could be partially inhibited by morphine.

Analgesics, Opioid↗
PubMedDate not supplied

Apolipoprotein E polymorphism in patients with Alzheimer's disease, vascular dementia and ischemic cerebrovascular disease.

Apolipoprotein E sigma4 allele (ApoE sigma4) is associated with Alzheimer's disease (AD) in familial and sporadic cases, but the associations of ApoE sigma4 allele and vascular dementia (VD) and/or ischemic cerebrovascular disease (ICVD) are still controversial. To clarify the associations of ApoE polymorphism with AD, VD and ICVD in Japanese, we examined ApoE polymorphism in samples of 255 patients with AD, 87 patients with VD, and 123 patients with ICVD, as compared with 117 age-matched healthy control subjects (CTL). The frequency of the ApoE sigma4 allele was significantly higher in the VD group (0.21), the ICVD group (0.15) as well as in the AD group (0. 26) than in the CTL subjects (0.08). These findings suggest that the genotype of ApoE sigma4 is associated with not only AD but also VD and ICVD, and that ApoE sigma4 plays an important role in the development of dementia and ICVD.

Aged↗
PubMedDate not supplied

Epidemiologic and genetic studies of dementia of the alzheimer type in japan.

We carried out two separate epidemiological studies on long-term changes, 10 years apart, on the prevalence rate of dementia in the elderly by the same method for the same area in Japan. We also performed a genetic study of patients with dementia of the Alzheimer type (DAT) based on the epidemiological studies. The number of patients with dementia was much larger in 1990 than in 1980. Especially, the number of mildly demented patients was significantly larger in 1990 than in 1980. The 35 patients with DAT did not show any mutations of amyloid-beta protein precursor, presenilin 1 and presenilin 2 genes. The frequency of apolipoprotein E (apo E) sigma4 allele in DAT was significantly higher than that in control subjects (p < 0.005). This study suggests that the frequency of DAT may increase by aging of the population in the future and we confirm the close association between apoE sigma4 allele and DAT in a community-based study in Japan.

Adolescent↗
PubMedDate not supplied

No association between apolipoprotein A-IV codon 360 mutation and late-onset Alzheimer's disease in the Japanese population.

Human apolipoprotein A-IV (apoA-IV) is genetically polymorphic, the apoA-IV polymorphism being controlled by two alleles, apoA-IV1 and apoA-IV2. The association between the apoA-IV2 allele and late-onset Alzheimer's disease (LOAD) has been reported in Caucasian populations. We investigated the codon 360 mutation of the apoA-IV gene allele frequency in 173 LOAD and in 158 age-matched control subjects of the Japanese population, and we found that the allele frequency of apoA-IV2 in the Japanese population was very rare and was extremely lower than in Caucasian populations. We conclude that there was no association between apoA-IV genotype and LOAD in the Japanese population. Copyrightz1999S.KargerAG,Basel

Age of Onset↗
PubMedDate not supplied

Estrogen receptor gene polymorphisms in patients with Alzheimer's disease, vascular dementia and alcohol-associated dementia.

The association between the estrogen receptor (ER-alpha) gene and dementia was examined in 223 patients with Alzheimer's disease (AD), 66 with vascular dementia (VD), 17 with alcohol-associated dementia (ALD) and 134 healthy elderly control subjects. The PvuII and XbaI restriction fragment length polymorphisms of the ER-alpha gene were represented as Pp (PvuII) and Xx (XbaI), with capital letters signifying the absence of restriction sites and small letters the presence of restriction sites. We found that the frequency of the ER-alpha gene P allele and X allele in the late-onset AD (LOAD) group (P allele was 0.51, X allele was 0.30) was significantly higher than that in controls (P 0.38, p < 0.01; X 0.20, p < 0.01), and that the frequency of the ER-alpha gene P allele and PP genotype was significantly different between apolipoprotein E epsilon4 carriers and noncarriers in LOAD. These findings suggest that the genotype of the ER-alpha gene may be specific in LOAD, and that the ER-alpha gene was an additional risk for LOAD.

Aged↗
PubMedDate not supplied

Lipoprotein(a) phenotypes in patients with vascular dementia.

We tried to examine if there is a particular distribution pattern of lipoprotein(a) [Lp(a)] phenotypes specific for patients with vascular dementia (VD). Fourteen cases of VD (9 males and 5 females), 18 cases of dementia of the Alzheimer type (DAT)(7 males and 11 females), 29 cases of cerebrovascular disease (CVD) in the chronic phase (18 males and 11 females) and 47 healthy individuals as controls (25 males and 22 females) were examined for serum Lp(a). Serum concentrations and phenotypes of Lp(a) were assessed by ELISA and a test kit for the Lp(a) phenotype, respectively. Serum concentrations of Lp(a) were significantly higher in patients with VD (p < 0.05) as well as patients with CVD (p < 0.01) compared with those in healthy individuals. Serum concentrations of Lp(a) did not significantly differ between patients with DAT and healthy individuals. The incidences of Lp(a) phenotypes containing relatively low-molecular-weight apolipoprotein(a) isoforms were significantly higher in patients with CVD in the chronic phase (p < 0.05) or those with VD (p < 0.01) compared with those in healthy individuals. Distribution patterns of Lp(a) phenotypes did not differ between patients with DAT and healthy individuals. Thus, high serum levels of Lp(a) could be considered a clinical hallmark to distinguish VD from DAT. Abnormally high serum levels of Lp(a) in patients with CVD and VD seemed to be due to specific increases in low-molecular-weight apolipoprotein(a) isoforms in Lp(a).

Aged↗
PubMedDate not supplied

The expression of presenilin 1 mRNA in skin fibroblasts and brains from sporadic Alzheimer's disease.

We examined the expression of presenilin 1 (PS-1) mRNA in cultured skin fibroblasts taken from living patients with Alzheimer's disease (AD) and human brains taken postmortem from AD patients by RT-PCR analysis. The donors of fibroblasts consisted of 28 cases with AD and 19 neurological patient without dementia (CTL). The brains came from 17 cases with AD and 23 cases with CTL. We found that PS-1 mRNA levels in skin fibroblasts of AD patients were significantly higher than those of CTL patients (p < 0.0001). Moreover, we found that PS-1 mRNA levels in human brains with AD were significantly higher than in those with CTL (p < 0.0001). These findings suggest that high levels of PS-1 mRNA in AD may play an important role in developing AD and that the examination of PS-1 mRNA in skin fibroblasts may be helpful for the diagnosis of AD.

Aged↗
PubMedDate not supplied

High expression of apolipoprotein E mRNA in the brains with sporadic Alzheimer's disease.

In order to study progressive dementia in Alzheimer's disease (AD) patients, we analyzed the gene expression of apolipoprotein E (apoE). ApoE mRNA level in the brains of patients with AD was determined by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. ApoE genotype and the promoter polymorphisms (-491A/T, Th1/E47cs) were determined by the PCR restriction fragment length polymorphism method. The apoE mRNA level was significantly higher in the AD group than the control group (p < 0.05). ApoE mRNA in the AD group with apoE epsilon 4 was also significantly higher than that in the control group with apoE epsilon 4 (p < 0.05). Our result did not indicate the possibility that the promoter polymorphisms modulate the apoE mRNA level. The higher level of apoE mRNA in AD with apoE epsilon4 may play an important role in the development of AD.

Aged↗
PubMedDate not supplied

Analysis of amyloid precursor protein mRNAs in skin fibroblasts in Down's syndrome.

We examined amyloid precursor protein (APP) mRNAs expression in skin fibroblasts from Down's syndrome (DS) patients of different ages to determine the time of occurrence of abnormal splicing. The ratio of APP770 + 751 mRNA to APP695 mRNA (APP770 + 751/695) was significantly increased in the young DS group and adult DS group compared with the age-matched control groups (p < 0.01, p < 0.05), but no significant increase was observed in the aged DS group compared with the age-matched control group. These findings suggest that metabolic abnormalities of the APP gene occur at a very early stage of DS, at a mean age of about 5 years. Therefore, metabolic abnormalities of the APP gene are considered to appear at a very young age also Alzheimer's disease (AD). In this study, we confirmed that examination of the APP gene in skin fibroblasts might be useful for early diagnosis of AD.

Adult↗
PubMedDate not supplied

Targeted overexpression of the sarcoplasmic reticulum Ca2+-ATPase increases cardiac contractility in transgenic mouse hearts.

Cardiac hypertrophy and heart failure are known to be associated with a reduction in Ca2+-ATPase pump levels of the sarcoplasmic reticulum (SR). To determine whether, and to what extent, alterations in Ca2+ pump numbers can affect contraction and relaxation parameters of the heart, we have overexpressed the cardiac SR Ca2+-ATPase specifically in the mouse heart using the alpha-myosin heavy chain promoter. Analysis of 2 independent transgenic lines demonstrated that sarco(endo)plasmic reticulum Ca2+-ATPase isoform (SERCA2a) mRNA levels were increased 3.88+/-0. 4-fold and 7.90+/-0.2-fold over those of the control mice. SERCA2a protein levels were increased by 1.31+/-0.05-fold and 1.54+/-0. 05-fold in these lines despite high levels of mRNA, suggesting that complex regulatory mechanisms may determine the SERCA2a pump levels. The maximum velocity of Ca2+ uptake (Vmax) was increased by 37%, demonstrating that increased pump levels result in increased SR Ca2+ uptake function. However, the apparent affinity of the SR Ca2+-ATPase for Ca2+ remains unchanged in transgenic hearts. To evaluate the effects of overexpression of the SR Ca2+ pump on cardiac contractility, we used the isolated perfused work-performing heart model. The transgenic hearts showed significantly higher myocardial contractile function, as indicated by increased maximal rates of pressure development for contraction (+dP/dt) and relaxation (-dP/dt), together with shortening of the normalized time to peak pressure and time to half relaxation. Measurements of intracellular free calcium concentration and contractile force in trabeculae revealed a doubling of Ca2+ transient amplitude, with a concomitant boost in contractility. The present study demonstrates that increases in SERCA2a pump levels can directly enhance contractile function of the heart by increasing SR Ca2+ transport.

Animals↗