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Biomedical subjects

S Ji

Publications and source records attributed to S Ji.

At least 73 records · Page 4Linked to original sources
PubMed1996

Dibutyl phthalate purged autologous bone marrow transplant in the treatment of leukemia.

It has been proved that di-N-butyl phthalate (DBP) is singular in killing leukemic cells selectively or accelerating the deterioration of residual leukemic cells in long-term marrow culture in vitro. Based on this principle, the DBP-purged autologous bone marrow transplant has been applied to the treatment of a group of 14 patients suffering from acute nonlymphocytic leukemia. After 5-10 days of in vitro co-culture of marrow cells with DBP at a concentration of 50 micrograms/ml, the recovery of total nucleated cells and the amount of CFU-GM were 67.5% and 68.1%, respectively. In all patients, the reconstitution of hematopoiesis was observed after pre-conditioning and transfusion of purged marrow cells. Among these, two patients had a relapse, two patients died from complications of transplant, one patient died from non-leukemic disease, and the others are all alive and free of disease; the mean survival time as calculated recently was 15 months. These preliminary clinical data support that marrow culture in the presence of DBP is a safe and effective measure for treating leukemia in purged autologous bone marrow transplant.

Adolescent↗
PubMed1996

Lactobacillus- and bifidobacterium-mediated antigenotoxicity in the colon of rats.

Lactic acid bacteria (LAB) are proposed to have several beneficial effects, including the inactivation of carcinogens. We have studied the potential of Lactobacillus acidophilus (from a commercially available yogurt), Lactobacillus gasseri (P79), Lactobacillus confusus (DSM20196), Streptococcus thermophilus (NCIM 50083), Bifidobacterium breve and Bifidobacterium longum (from human infant stool) to prevent the induction of DNA damage by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 7.5 mg/kg body wt) in colon cells of the rat. Using the new technique of single cell microgel electrophoresis, all investigated strains were antigenotoxic toward MNNG after a single dose of 10(10) viable cells/kg body wt p.o. eight hours before the carcinogen. One-half and one-tenth of this initial dose resulted in a loss of protective activity. High doses of heat-treated L. acidophilus strains were also not antigenotoxic. One mechanism of the preventive effect could be that bacterial metabolites or components are responsible. Accordingly, selected examples were investigated in vitro in colon cells of the rat. Metabolically active L. acidophilus cells, as well as an acetone extract of the culture, prevented MNNG-induced DNA damage. Different cell fractions from L. acidophilus (cytoplasm, cell wall skeleton, cell wall) were devoid of antigenotoxic activity, whereas the peptidoglycan fraction and whole freeze-dried cells were antigenotoxic. As a second carcinogen, 1,2-dimethylhydrazine (DMH) was used. A dose- and time-response study was first performed to assess the effects of DMH in several segments of the gastrointestinal (GI) tract. Exposure for 16 hours to 15 or 25 mg DMH/kg body wt p.o. induced DNA damage in cells of the distal colon of rats, whereas no cytotoxicity was seen. Pretreatment orally with LAB on four consecutive mornings before DMH gavage (8 hours after the last LAB application) revealed that L. acidophilus, L. confusus, L. gasseri, B. longum, and B. breve inhibited the genotoxic effect of DMH. One of four S. thermophilus and one of three Lactobacillus delbrueckeii ssp. bulgaricus strains were also protective. Heat-treated L. acidophilus did not inhibit DMH-induced genotoxicity. A few aliquots of the colon cells were processed immunohistochemically for the presence of the "proliferation cell nuclear antigen" (PCNA). DMH treatment did not increase PCNA, nor was there any modulation by LAB. The effect of L. acidophilus on foreign compound-metabolizing enzymes (Phase I and Phase II) in liver and colon cells of rats revealed only one parameter to be modulated, namely, a two- to three-fold increase in the levels of NADPH-cytochrome P-450 reductase. The meaning of this finding, in terms of possible chemoprevention by LAB, remains unclear. In conclusion, our studies show that most, but not all, LAB tested could strongly inhibit genotoxicity in the GI tract of the rat and that viable LAB organisms are required for the protective effect in vivo. The comet assay technique is a powerful tool to elucidate such in vivo antigenotoxic activities in tumor target tissues.

1,2-Dimethylhydrazine↗
PubMed1996

Paramyotonia congenita mutations reveal different roles for segments S3 and S4 of domain D4 in hSkM1 sodium channel gating.

Mutations in the gene encoding the voltage-gated sodium channel of skeletal muscle (SkMl) have been identified in a group of autosomal dominant diseases, characterized by abnormalities of the sarcolemmal excitability, that include paramyotonia congenita (PC) and hyperkalemic periodic paralysis (HYPP). We previously reported that PC mutations cause in common a slowing of inactivation in the human SkMl sodium channel. In this investigation, we examined the molecular mechanisms responsible for the effects of L1433R, located in D4/S3, on channel gating by creating a series of additional mutations at the 1433 site. Unlike the R1448C mutation, found in D4/S4, which produces its effects largely due to the loss of the positive charge, change of the hydropathy of the side chain rather than charge is the primary factor mediating the effects of L1433R. These two mutations also differ in their effects on recovery from inactivation, conditioned inactivation, and steady state inactivation of the hSkMl channels. We constructed a double mutation containing both L1433R and R1448C. The double mutation closely resembled R1448C with respect to alterations in the kinetics of inactivation during depolarization and voltage dependence, but was indistinguishable from L1433R in the kinetics of recovery from inactivation and steady state inactivation. No additive effects were seen, suggesting that these two segments interact during gating. In addition, we found that these mutations have different effects on the delay of recovery from inactivation and the kinetics of the tail currents, raising a question whether this delay is a reflection of the deactivation process. These results suggest that the S3 and S4 segments play distinct roles in different processes of hSkM1 channel gating: D4/S4 is critical for the deactivation and inactivation of the open channel while D4/S3 has a dominant role in the recovery of inactivated channels. However, these two segments interact during the entry to, and exit from, inactivation states.

Adult↗
PubMed1996

The efficiency of respiratory muscle strengthening training programs in pilots.

OBJECTIVE: To evaluate the efficiency of respiratory muscle training programs in pilots. METHODS: Twenty-four male pilots were divided into two groups. The training group (12 pilots) underwent respiratory strengthening training programs besides routine physical exercises. The other 12 pilots in the control group only did routine physical exercises, but the training time was the same in these two groups. Before and after training programs in the two groups, the respiratory muscle functions were examined. RESULTS: 24 pilots in these two groups completed training programs within four weeks. The pilots in the training group got improvement of respiratory muscle functions which was much better than those of the control group. CONCLUSION: It suggests that the strengthening training programs of respiratory muscles can improve and strengthen the respiratory muscle functions in pilots.

Adult↗
PubMed1996

[High-dose chemotherapy supported by peripheral blood stem cells to treat intermediate--and high-grade non-Hodgkin's lymphomas].

In this study, 16 eligible patients with intermediate and high-grade non-Hodgkin's lymphoma were treated with a new high-dose DHACT regimen supported by rhG-CSF and peripheral blood stem cell (PBSC) rescue. PBSC were mobilized by rhG-CSF or rhGM-CSF. Single leukapheresis was performed and the PBSC were then frozen in liquid nitrogen. CFU-GM clonogenic assay for mononuclear cells and resuscitated progenitor cells done to calculate how many progenitor cells were alive after freezing. The DHACT chemotherapy was composed of carboplatin 600 mg/m2 on d1, Ara-C 1500 mg/m2 on d2, VM-26 100 mg/m2 on d3, 4, and dexamethasone 40 mg/d, on d1-4. Autologous PBSC was reinfused after 24 to 48 hours of chemotherapy. Recombinant human G-CSF at 300 micrograms administered daily on 2 successive days when the absolute neutrophil count was greater than 1 x 10(9)/L. Other supportive care procedures were standard for the unit. The median amount of PBSC reinfused into a patient was 0.9 x 10(8)/kg. The recovery rate of CFU-GM was 78% after cryopresevation. Within 7 to 9 days after high-dose DHACT chemotherapy, the WBC count and the platlet count arrived nadir, and then rose gradually with rhG-CSF injection. The median time for WBC count from nadir to > or = 1 x 10(9)/L was 4 days, and that for platelet count from nadir to > or = 50 x 10(9)/L was 7 days. Nine patients achieved complete remission and 5 patients achieved partial remission. The median follow-up on survival was 9 months. High-dose DHACT regimen supported by rhG-CSF and PBSC rescue is a safe and effective treatment for patients with advanced intermediate and high-grade non-Hodgkin's lymphoma.

Adolescent↗
PubMed1995

Essential and neural transcripts from the Drosophila shaking-B locus are differentially expressed in the embryonic mesoderm and pupal nervous system.

The shaking-B gene of Drosophila encodes two functions: one specifically neural and the other required for viability. Flies carrying neural mutations show a range of defects, the best characterized of which is a disruption of some synapses in the giant fibre system, while mutations in the essential function cause animals to die as first instar larvae. We have characterised an essential transcript from this locus and show that mutant lesions underlying two lethal shaking-B alleles map to its coding sequence. We also propose a new model for the topologies of Shaking-B proteins and their relatives. Essential shaking-B transcripts are found in embryonic mesodermal derivatives, while during metamorphosis both essential and neural transcripts are dynamically expressed in the pupal nervous system. Although the expression patterns of these transcripts overlap in many cells, only the neural form is expressed in the giant fibre cell bodies and the lamina and medulla of the optic lobes. This observation correlates with the phenotypes of mutations which disrupt the coding region of this neural transcript. On the basis of the expression patterns of shaking-B transcripts and the phenotypes conferred by mutations of shaking-B and homologous genes, we suggest that Shaking-B proteins and their homologues may be involved in the organisation of cellular membranes.

Alleles↗
PubMed1995

An experimental study of spinal cord evoked potential.

The characteristics of spinal cord-evoked potentials were investigated by using an in vitro spinal cord preparation. The spinal cord isolated from adult rats was immersed in a bathing chamber filled with oxygenated artificial cerebrospinal fluid (aCSF). The spinal cord-evoked potentials elicited by the stimulation of the spinal cord were recorded by using bipolar platinum electrodes. The potentials recorded consisted of early and late negative components (N1, N2). The inhibitory effect of lowered temperature on the N1 potential was clearly demonstrated. The oxygen deprivation of aCSF showed the higher sensitivity of N2 potential to hypoxia than that of N1. It was also possible to analyze the effects of potassium and magnesium ion concentration and pH on the evoked potentials. These results showed that the pure effects of various physiological and chemical factors on the spinal cord-evoked potentials can be analyzed by this experimental model.

Animals↗
PubMed1995

[Electroacupuncture promotes enlargement of adrenals and enhances level of blood corticosterone in ovariectomized rats].

The present article reports EA with special acupoints may promote the enlargement of bilateral adrenals and enhance the level of blood corticosterone in ovariectomized (OV) rats. The mean of adrenal weight (M +/- SE, mg) as following, OV + EA group 71 +/- 2.1, OV group 57.4 +/- 4.7, EA group 57.6 +/- 1.1 and control group (CT group) 54 +/- 2.8 respectively. For observation of a self control, the detection of blood corticosterone contents was performed in the same animals before and after ovariectomy. The results showed that before ovariectomy the contents of blood corticosterone in the rats were 3.27 +/- 0.7 micrograms/100ml before EA and 3.63 +/- 0.9 micrograms/100ml after EA. No significant difference of blood corticosterone level was found before and after EA. After the animals ovariectomized the level of blood corticosterone increased from 4.38 +/- 0.62 micrograms/100ml to 6.02 +/- 0.77 micrograms/100ml following EA treatment (P < 0.01). No similar effect of EA treatment with control acupoints in OV rats was seen. These results suggest that EA may regulate the abnormal function of endocrine and this effect of EA possesses relative specificity of acupoint.

Adrenal Glands↗
PubMed1994

Sodium channel mutations in paramyotonia congenita exhibit similar biophysical phenotypes in vitro.

Mutations in the skeletal muscle voltage-gated Na+ channel alpha-subunit have been found in patients with two distinct hereditary disorders of sarcolemmal excitation: hyperkalemic periodic paralysis (HYPP) and paramyotonia congenita (PC). Six of these mutations have been functionally expressed in a heterologous cell line (tsA201 cells) using the recombinant human skeletal muscle Na+ channel alpha-subunit cDNA hSkM1. PC mutants from diverse locations in this subunit (T1313M, L1433R, R1448H, R1448C, A1156T) all exhibit a similar disturbance in channel inactivation characterized by reduced macroscopic rate, accelerated recovery, and altered voltage dependence. PC mutants had no significant abnormality in activation. In contrast, one HYPP mutation studied (T704M) has a normal inactivation rate but exhibits shifts in the midpoints of steady-state activation and inactivation along the voltage axis. These findings help to explain the phenotypic differences between HYPP and PC at the molecular and biophysical level and contribute to our understanding of Na+ channel structure and function.

Base Sequence↗
PubMed1994

Metabolism of benzene and trans,trans-muconaldehyde in the isolated perfused rat liver.

Perfusate from rat livers perfused with benzene (approximately 0.7-7 x 10(-4) M) or trans,trans-muconaldehyde (MUC) (10(-4) M) was extracted and analyzed by reverse-phase HPLC. Based on retention time and co-elution experiments, benzene was found to be metabolized to trans,trans-muconic acid, a urinary ring-opened metabolite of benzene and a major in vivo and in vitro metabolite of MUC. These data demonstrate that benzene ring-opening occurs in the liver. Following perfusion with MUC (a microsomal hematotoxic metabolite of benzene), trans,trans-muconic acid and three other MUC metabolites were detected in the perfusate extract, suggesting that these metabolites would be present in the circulation following metabolism of MUC.

Aldehydes↗
PubMed1994

Sodium channel mutations in paramyotonia congenita uncouple inactivation from activation.

Mutations in the adult human skeletal muscle Na+ channel alpha subunit cause the disease paramyotonia congenita. Two paramyotonia congenita mutations, R1448H and R1448C, substitute histidine and cysteine for arginine in the S4 segment of domain 4. These mutations, expressed in a cell line, have only small effects on the activation of Na+ currents, but mutant channels inactivate more slowly with less voltage dependence than wild-type channels and exhibit an enhanced rate of recovery from inactivation. Increase of extracellular pH made the rate of inactivation of R1448H similar to that of R1448C, suggesting that this residue has an extracellular location and that its charge is important for normal inactivation. Analysis of single-channel data reveals that mutant channels inactivate normally from closed states, but poorly from the open state. The data suggest a critical role for the S4 helix of domain 4 in coupling between activation and inactivation.

Base Sequence↗
PubMed1994

Voltage-dependent regulation of modal gating in the rat SkM1 sodium channel expressed in Xenopus oocytes.

The TTX-sensitive rat skeletal muscle sodium channel (rSkM1) exhibits two modes of inactivation (fast vs slow) when the alpha subunit is expressed alone in Xenopus oocytes. In this study, two components are found in the voltage dependence of normalized current inactivation, one having a V1/2 in the expected voltage range (approximately -50 mV, I(N)) and the other with a more hyperpolarized V1/2 (approximately -130 mV, IH) at a holding potential of -90 mV. The I(N) component is associated with the gating mode having rapid inactivation and recovery from inactivation of the macroscopic current (N-mode), while IH corresponds to the slow inactivation and recovery mode (H-mode). These two components are interconvertible and their relative contribution to the total current varies with the holding potential: I(N) is favored by hyperpolarization. The interconversion between the two modes is voltage dependent and is well fit to a first-order two-state model with a voltage dependence of e-fold/8.6 mV and a V1/2 of -62 mV. When the rat sodium channel beta 1-subunit is coinjected with rSkM1, IH is essentially eliminated and the inactivation kinetics of macroscopic current becomes rapid. These two current components and their associated gating modes may represent two conformations of the alpha subunit, one of which can be stabilized either by hyperpolarization or by binding of the beta 1 subunit.

Animals↗
PubMed1994

[The effects of naloxone and electroacupuncture on the release of GnRH from female rat's preoptic area].

By means of push-pull perfusion technique and the special radioimmunoassay we determined the GnRH concentration of the perfusates from preoptic area (POA) in ovariectomized (OVX) and intact (INT) female rats, to observe the influence of naloxone and electroacupuncture (EA) on the release of GnRH and beta-endorphin from POA. The results show that the basic GnRH level of POA perfusate in OVX was 271.8 +/- 77.5pg/ml and that in INT was 52.4 +/- 11.1pg/ml. There was a significant difference between the basic levels of two groups (P < 0.02, n = 12). No difference of beta-endorphin basic level in OVX and INT was found. The GnRH level of POA perfusate in OVX was increased by 146.6 +/- 46.5pg/ml (P < 0.01, n = 12) 30 minutes after intraperitoneal administration of naloxone, but no obvious change was found in INT following naloxone administration. EA treatment had no effect on the release of GnRH and beta-endorphin in both OVX and INT. The results suggest that the negative feedback of estrogen may be a major regulative factor of GnRH under the normal condition and after the abolition of estrogen feedback induced by ovariectomy the central opioid peptide might be the main regulative mechanism for GnRH.

Animals↗
PubMed1994

[The effects of electroacupuncture treatment on nucleolar organizer regions of adrenal cortex in ovariectomized rats].

The present paper reports the morphometric analysis of nucleolar organizer regions (NORs) of the adrenal cortex in ovariectomized rats following electroacupuncture (EA) using argyrephil (Ag-NOR) method for NORs. Animals were divided into four groups, the control group (CT group, n = 4), the EA group (n = 3), the ovariectomized group (OV group, n = 4) and the ovariectomized electroacupuncture group, (OV+EA group, n = 7). The number of AgNORs of 100 cells from zona fasciculata of the adrenal cortex in each case of all groups was counted at random and the mean +/- SE (number/cell) in each group was calculated as follows: OV+EA group 2.71 +/- 0.26, OV group 1.62 +/- 0.15, EA group 1.21 +/- 0.04 and CT group 1.48 +/- 0.03. The mean of AgNORs in OV+EA group differed highly significantly from the other three groups (P < 0.01) tested by ANOVA and LSD method, No significant distinction was found among the OV group, EA group and CT group. Gross specimen examination showed that adrenal glands in OV+EA were significantly heavier than those in the other three groups (P < 0.01). Vaginal smears showed that a response like that of estrogen-induced with exfoliative cells appeared in the OV+EA group rats following EA. EA had no influence on the change of exfoliative cells in EA group. The results suggest that EA may promote the synthesis and secretion of the adrenal steroid hormones, the androgen of which will then be transformed into estrogen in other tissues, thus compensating the deficiency of estrogen induced by ovariectomy.

Adrenal Cortex↗
PubMed1993

Modulation of voltage-dependent sodium and potassium currents by charged amphiphiles in cardiac ventricular myocytes. Effects via modification of surface potential.

Modulation of voltage-dependent sodium and potassium currents by charged amphiphiles was investigated in cardiac ventricular myocytes using the patch-clamp technique. Negatively charged sodium dodecylsulfate (SDS) increased amplitude of INa, whereas positively charged dodecyltrimethylammonium (DDTMA) decreased INa. Furthermore, SDS shifted the steady-state activation and inactivation of INa in the negative direction, whereas DDTMA shifted the curves in the opposite direction. These shifts provided an explanation for the changes in current amplitude. Activation and inactivation kinetics of INa were accelerated by SDS but slowed by DDTMA. These changes in both steady-state gating and kinetics of INa are consistent with a decrease of the intramembrane field by SDS and an increase of the field by DDTMA due to an alteration of surface potential after their insertion into the outer monolayer of the sarcolemma. The effect of SDS on the steady-state inactivation of INa was concentration dependent and partially reversed by screening surface charges with increased extracellular [Ca2+]. These amphiphiles also altered the activation of the delayed rectifier K+ current (IK,del), producing a shift in the negative direction by SDS but in the positive direction by DDTMA. These results suggest that the insertion of charged amphiphiles into the cell membrane alters the behavior of voltage-dependent INa and IK,del by changing the surface charge density, and consequently the surface potential and implies, although indirectly, that the lipid surface charges are important to the voltage-dependent gating of these channels.

Animals↗