PubMed Health⌕ Search

Biomedical subjects

X Ge

Publications and source records attributed to X Ge.

At least 37 records · Page 2Linked to original sources
PubMed1999

Attenuation of morphine tolerance and dependence in scopolamine-treated rats.

Morphine tolerance and dependence were investigated in scopolamine-treated rats. The results showed that scopolamine treatment (up to 2 mg/kg) did not affect basal line or morphine-induced latency in the tail-flick test but significantly increased the escape latency in the Morris water-maze task. Co-administration of scopolamine could considerably attenuate development of morphine tolerance and naloxone-precipitated withdrawal syndrome. Pretreatment of scopolamine for 7 days prior to morphine administration also significantly reduced the tolerance and withdrawal symptoms. Scopolamine treatment was further shown to attenuate morphine-induced conditioned place preference, an indicator of morphine psychological dependence. The present study demonstrated the attenuation of morphine tolerance and dependence in scopolamine-treated animals, probably related to scopolamine-produced learning and memory impairment.

Analgesics, Opioid↗
PubMed1999

Administration of the tris salt of alpha-tocopheryl hemisuccinate inactivates CYP2E1, enhances microsomal alpha-tocopherol levels and protects against carbon tetrachloride-induced hepatotoxicity.

A series of tocopherol compounds were examined for their capacity to protect against carbon tetrachloride (CCl4)-induced hepatotoxicity in rats. Of the tocopherol compounds tested in our study, only the tris salt of d-alpha-tocopheryl hemisuccinate (TS-tris) protected against CCl4-induced hepatotoxicity. The administration of d-alpha-tocopherol (alpha-T) and the nonhydrolyzable tocopherol ether, d-alpha-tocopheryloxybutyrate tris salt (TSE-tris), failed to protect against CCl4-induced hepatotoxicity. TS-tris was the only tocopherol which significantly decreased CYP2E1 activity after 18 h. This decrease in CYP2E1 activity is likely to limit the activation of CCl4 and protect against CCl4-induced hepatotoxicity. Our results also suggest that TS-tris protection against CCl4-induced hepatotoxicity correlates with the enhanced capacity of TS-tris to deliver alpha-T and increase the antioxidant status of hepatocytes. TSE-tris did not increase cellular alpha-T levels, while administration of TS-tris produced large increases in alpha-T levels in liver homogenates as well as in liver nuclei, microsomes, mitochondria and plasma membranes. This enhanced ability to deliver tocopherol equivalents to parenchymal liver cells may be related in part to the ability of TS-tris to form liposomes in aqueous solutions. TS-tris administration protected against CCl4-induced microsomal lipid peroxide formation and inactivation of the microsomal enzyme glucose-6-phosphatase (G6Pase). Supplementation of animals with alpha-T protected against microsomal lipid peroxide formation but not against the inactivation of G6Pase. Based on our findings, we propose that high cellular levels of alpha-T protect against CCl4-induced hepatotoxicity by scavenging CCl4 radicals as well as protecting against lipid peroxidation. Our results do not support the importance of microsomal lipid peroxidation as an early event in acute CCl4-induced hepatic necrosis.

Alanine Transaminase↗
PubMed1999

Adjustment problems and emerging personality characteristics from early to late adolescence.

This 6-year longitudinal study extended earlier findings of contextual influences on adolescent adjustment problems by examining relationships between adolescent emotional and behavioral problems and late adolescent personality among more than 400 youths who were followed from 7th grade to the last year of high school. Results suggest that psychological distress and behavioral problems experienced during the adolescent years (7th-10th grades) are significantly related to personality structure during the final year of high school (12th grade). Psychological distress in adolescence was primarily related to the Multidimensional Personality Questionnaire (MPQ) superfactors of negative and positive emotionality, whereas delinquency and substance use problems were primarily related to the MPQ superfactor of constraint. These relationships remained significant even when personality characteristics in 9th grade were taken into account. That is, emotional and behavioral problems predicted change in personality traits during the adolescent years. Moreover, both initial level and change in distress and problem behaviors were predictive of late adolescent or early adult personality. This finding suggests that personality formation is a dynamic process, dependent on the growth or decline, as well as the magnitude of earlier developmental problems. Because earlier research has shown that these developmental problems are affected by both distal and proximal environmental contexts as well as by the formative nature of adolescence, intervention efforts aimed at the reduction of maladjustment and the enhancement of healthy personality development should target early adolescent social contexts. Other theoretical implications of the findings also are discussed.

Adjustment Disorders↗
PubMed1999

Stapedectomy for far-advanced otosclerosis.

OBJECTIVE: This study aimed to describe far-advanced otosclerosis and to present the authors' results with stapedectomy in 78 ears with far-advanced otosclerosis. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at an Otology/Neurotology tertiary referral center. PATIENTS: Stapedectomy was performed on 78 ears of 60 patients with far-advanced otosclerosis, and the results followed from 1 to 21 years with a mean of 5 years. INTERVENTION: Stapedectomy was performed on all ears with far-advanced otosclerosis. MAIN OUTCOME MEASURE: Hearing for air conduction (AC) and bone conduction (BC), speech discrimination, and impedance were tested on all patients before and after operation. The Rinne test was performed on all ears with a 256-cycle magnesium tuning fork. The pure-tone average for AC and BC was computed for 500, 1,000, and 2,000 Hz. Hearing improvement was defined as air-bone gap closure to 10 dB or less and/or AC improvement of 20 dB or more, with no decline in speech discrimination score of more than 10%. RESULTS: Hearing improvement was achieved in 52 (66.7%) of 78 ears of all operations. In group 1, AC was greater than 90 dB, BC was greater than 60 dB, and hearing improved in 26 (81.2%) of 32 ears of operations. In group 2, AC was greater than 90 dB and no measurable BC and hearing improved in 11 (68.8%) of 16 ears of operations. In group 3, there was no measurable AC and BC greater than 60 dB and hearing improved in two (50%) of four ears of operations. In group 4, there was no measurable AC and BC and hearing improved in 11 (42.3%) of 26 ears of operations. Nonmeasurable BC became measurable in 42.9% of ears, nonmeasurable AC became measurable in 73.3% of ears, and all of these became aidable after operation. CONCLUSIONS: A negative Rinne test result with a 256-Hz magnesium tuning fork proved to be the best test to separate far-advanced otosclerosis from sensorineural hearing loss of other causes. Stapedectomy is of benefit in most ears with profound hearing loss of far-advanced otosclerosis, especially in those ears with some measurable hearing by AC.

Adolescent↗
PubMed1998

A viral suppressor of gene silencing in plants.

Gene silencing is an important but little understood regulatory mechanism in plants. Here we report that a viral sequence, initially identified as a mediator of synergistic viral disease, acts to suppress the establishment of both transgene-induced and virus-induced posttranscriptional gene silencing. The viral suppressor of silencing comprises the 5'-proximal region of the tobacco etch potyviral genomic RNA encoding P1, helper component-proteinase (HC-Pro) and a small part of P3, and is termed the P1/HC-Pro sequence. A reversal of silencing assay was used to assess the effect of the P1/HC-Pro sequence on transgenic tobacco plants (line T4) that are posttranscriptionally silenced for the uidA reporter gene. Silencing was lifted in offspring of T4 crosses with four independent transgenic lines expressing P1/HC-Pro, but not in offspring of control crosses. Viral vectors were used to assess the effect of P1/HC-Pro expression on virus-induced gene silencing (VIGS). The ability of a potato virus X vector expressing green fluorescent protein to induce silencing of a green fluorescent protein transgene was eliminated or greatly reduced when P1/HC-Pro was expressed from the same vector or from coinfecting potato virus X vectors. Expression of the HC-Pro coding sequence alone was sufficient to suppress virus-induced gene silencing, and the HC-Pro protein product was required for the suppression. This discovery points to the role of gene silencing as a natural antiviral defense system in plants and offers different approaches to elucidate the molecular basis of gene silencing.

Journal Article↗
PubMed1998

The sequence of RNA 1 and RNA 2 of tobacco streak virus: additional evidence for the inclusion of alfalfa mosaic virus in the genus Ilarvirus.

Here we describe the complete sequence of RNA 1 and 2 of the WC isolate of tobacco streak virus (TSV). These two sequences complete the information on the genome of TSV, the type member of the genus Ilarvirus, and are the first sequences described for the RNA 1 and RNA 2 of a member of subgroup 1 of this genus. The sequences have a similar organization to those reported for the corresponding RNAs of other ilarviruses. However, the putative translation products of these two molecules differ sufficiently from previously sequenced ilarviruses so that TSV should remain in a subgroup on its own. Phylogenetic comparison of sequence data for RNA 1 with that of other ilarviruses and alfalfa mosaic virus (AMV) reveals two distinct clusters (TSV, CiLRV, and SpLV) and (AMV, PDV, and ApMV). These data support the suggestion [16] based on data for RNA 3 of ilarviruses that AMV should be included as a true ilarvirus.

Alfalfa mosaic virus↗
PubMed1998

[A study on efficacy of rabies vaccine prepared by primary hamster kidney cells in Guangxi].

OBJECTIVE: To study the efficacy of post-exposure use of concentrated rabies vaccine prepared by primary hamster kidney cells during the past 16 years (1980-1995) in the Guangxi Zhuang Autonomous Region and the role of ambulant care for the victims injured by dog-bite. METHODS: Data of rabies incidence notified from all the prefectures and cities in Guangxi were summarized and corroborated, field studies were conducted and rabies antibodies were determined. RESULTS: Incidence of rabies fell to 0.04 per ten thousand in 1995 from 2.46 per ten thousand in 1981 with increased use of post-exposure rabies immunization with concentrated vaccine and in-time treatment for dog-bite wounds in the widespread ambulant care settings. CONCLUSION: Rabies vaccine prepared by primary hamster kidney cells has good efficacy in protection from rabies and early and in-time treatment for dog-bite wounds could enhance their protective effects. It is suggested that concentrated vaccine be purified to avoid adverse effects caused by its allergen.

Animals↗
PubMed1998

[Treatment of venous reflux disease of the leg by deep-venous valve reconstruction].

UNLABELLED: In order to evaluate the effect and indication of three kinds of deep-venous valve reconstruction surgery, 62 cases with venous reflux disease of the leg had been treated from Jan. 1992 to Jun. 1996. All the patients had varicose vein and tingle in varying degrees, besides swelling in 30 cases, pigmentation in 28 cases, ulcer in 14 cases. The course of disease ranged from 1 to 30 years (averaged 14.6 years). METHOD: 14 cases were treated by ringing of the superficial femoral venous 1st valve, 1 case was treated by repairing of the superficial femoral venous 1st valve, 47 cases were treated by formation of substitute valve outside the popliteal vein. The symptoms of all the patients were alleviated with an average follow-up for 20 months. Fourteen cases with ulcer were healed compeletely and no recurrence. The conclusion were: 1. ringing and repairing of the venous valve were suitable for level I-II venous valvular incompetence. 2. formation of substitute valve outside the popliteal vein was suitable for level III-IV venous valvular incompetence or congenital valvular defect. 3. the width of the ringing material should be increased to 2 cm according to the pathological basis. 4. both femoral veins should be ringed in the treatment of primary valvular incompetence of double deep vein deformity. 5. the formation of substitute valve outside the popliteal vein was also available in the treatment of popliteal vein with many branches.

Adult↗
PubMed1997

The complete sequence of the genomic RNAs of spinach latent virus.

We describe the sequence for the complete genome of spinach latent virus (SpLV). Comparisons of this genome with that of the only other complete genome described for a species within the genus Ilarvirus (citrus leaf rugose virus-CiLRV) indicate that while there are marked differences between the RNA 3 of the two viruses, their respective RNAs 1 and 2 share many similarities. However, the putative 2a protein of SpLV contains a C2H2 type "zinc finger"-like motif located towards the carboxy terminal of the protein which is absent in CiLRV and has not been reported for other members of the family Bromoviridae. A second open reading frame (2b), located at a similar position to that described for the cucumoviruses, occurs in the RNA 2 of both SpLV and CiLRV. The putative coat protein of SpLV is similar to that of citrus variegation virus (CVV) and asparagus virus 2 (AV-2), both members of subgroup 2 of the ilarviruses. We have subsequently demonstrated a serological relationship between SpLV and other viruses in subgroup 2 and suggest that SpLV should be included in this subgroup rather than remain in a separate group (subgroup 6). However, while the putative movement protein of SpLV is remarkably similar to that of AV-2, it shows little relationship with the corresponding protein of CVV and the lack of similarity suggests that a recombination event may have occurred in the past. The relationship between the genera Alfamovirus and Ilarvirus is discussed in the light of the data for the genome of SpLV and recently published information for other members of the genus Ilarvirus.

Amino Acid Sequence↗
PubMed1997

Inhibitory effect of Tripterygium wilfordii multiglycoside on increased glomerular albumin permeability in vitro.

BACKGROUND: Tripterygium wilfordii Hook F is a medicinal plant used for the treatment of glomerulonephritis in China. We studied the effect of Tripterygium wilfordii multiglycoside (TWG) on glomerular albumin permeability (Palbumin) in vitro. METHODS: Isolated rat glomeruli were incubated with protamine (600 micrograms/ml) for 30 min, or with human recombinant tumour necrosis factor (TNF-alpha 0.4 ng/ml), superoxide (10 units/ml), or serum from a focal segmental glomerular sclerosis (FSGS) patient for 10 min at 37 degrees C. TWG, 1 mg/ml, was added in parallel tubes to study the effect on Palbumin. Control glomeruli were incubated under identical conditions. The albumin reflection coefficient (sigma albumin) was calculated from the change in glomerular volume in response to an applied oncotic gradient. Convectional permeability (Palbumin) was calculated as (1 - sigma albumin). RESULTS: Compared with controls, protamine increased the Palbumin of glomeruli (0.83 +/- 0.05, n = 25, vs 0.18 +/- 0.03, n = 20); pretreatment with TWG blocked this effect (0.13 +/- 0.04, n = 25). TNF-alpha also increased the Palbumin (0.79 +/- 0.04, n = 24 vs 0.04 +/- 0.07, n = 19); preincubation with TWG blocked this effect (0.03 +/- 0.09, n = 24). Palbumin of glomeruli incubated with xanthine and xanthine oxidase, resulting in the production of superoxide, also increased as compared to controls (0.85 +/- 0.04, n = 15 vs 0.08 +/- 0.05, n = 14); TWG blocked this effect as well (0.21 +/- 0.08, n = 14). FSGS serum also increased Palbumin of glomeruli significantly (0.88 +/- 0.02, n = 49 vs 0.00 +/- 0.02, n = 49); preincubation with TWG blocked this effect (0.05 +/- 0.07, n = 30). TWG by itself had no effect on Palbumin (0.19 +/- 0.10, n = 15). CONCLUSIONS: Our results show that TWG blocks protamine, TNF-alpha, superoxide, and FSGS serum-mediated increase in glomerular albumin permeability in vitro. We conclude that reduction of proteinuria by Tripterygium wilfordii multiglycoside in various kinds of glomerular diseases in vivo might be due to protection of the glomerular filtration barrier.

Animals↗
PubMed1997

Plant viral synergism: the potyviral genome encodes a broad-range pathogenicity enhancer that transactivates replication of heterologous viruses.

Synergistic viral diseases of higher plants are caused by the interaction of two independent viruses in the same host and are characterized by dramatic increases in symptoms and in accumulation of one of the coinfecting viruses. In potato virus X (PVX)/potyviral synergism, increased pathogenicity and accumulation of PVX are mediated by the expression of potyviral 5' proximal sequences encoding P1, the helper component proteinase (HC-Pro), and a fraction of P3. Here, we report that the same potyviral sequence (termed P1/HC-Pro) enhances the pathogenicity and accumulation of two other heterologous viruses: cucumber mosaic virus and tobacco mosaic virus. In the case of PVX-potyviral synergism, we show that the expression of the HC-Pro gene product, but not the RNA sequence itself, is sufficient to induce the increase in PVX pathogenicity and that both P1 and P3 coding sequences are dispensable for this aspect of the synergistic interaction. In protoplasts, expression of the potyviral P1/HC-Pro region prolongs the accumulation of PVX (-) strand RNA and transactivates expression of a reporter gene from a PVX subgenomic promoter. Unlike the synergistic enhancement of PVX pathogenicity, which requires only expression of HC-Pro, the enhancement of PVX (-) strand RNA accumulation in protoplasts is significantly greater when the entire P1/HC-Pro sequence is expressed. These results indicate that the potyviral P1/HC-Pro region affects a step in disease development that is common to a broad range of virus infections and suggest a mechanism involving transactivation of viral replication.

Cucumovirus↗
PubMed1997

[TGF beta 1 on murine tumor growth following direct intratumoral injection of plasmid DNA].

OBJECTIVE: To investigate TGF beta 1 gene expression and its effect on murine tumor growth following direct intratumoral injection of naked plasmid DNA encoding human TGF beta 1. METHODS: LM3 murine lung adenocarcinoma cells, were injected subcutaneously to T739 mice and grew to tumor nodules in 2 weeks, Multiple direct intratumoral injections of plasmid DNA, PMAM-neo-TGF beta 1, were given and were compared with saline or vector plasmid administration groups. The growth of tumor was observed till the 8th week when the mice were killed for Northern blot analysis and histopathological study of tumoral tissue. RESULTS: The growth of tumor was boosted in the TGF beta 1 gene treated mice as compared with the control groups, whereas there was no significant difference in the metastatic behavior. Northern blot showed efficient expression of TGF beta 1 mRNA in the treated group. CONCLUSION: TGF beta 1 may stimulate tumor growth in vivo through certain mechanisms. Direct intratumoral injection of nude plasmid DNA may be a promising gene transfer strategy in vivo.

Adenocarcinoma↗
PubMed1997

[Suppression of metastatic phenotype of cloned mouse lung adenocarcinoma cells by transfer of human genomic DNA].

OBJECTIVE: To isolate and identify human sequences with metastatic suppression ability. METHODS: Genomic DNA fragments isolated from normal human lung tissue were transfected into cloned highly metastatic mouse lung adenocarcinoma cells together with PSV2neo as selectable marker. RESULTS: 25 transfectants were cloned in medium containing G418 and Ouabain. Eight morphologically flat revertants exhibited a more normal phenotype, six clones containing human DNA were identified by a sensitive Inter Alu-PCR method. The rate of cell growth and colony formation in agar were detected in vitro. Clone 12, 20 and 32 showed a lower ratio than maternal untransfected cells. In vivo clone 12 showed more significent less spontaneous metastases in nude mice and syngeneic T739 mouse than control group. CONCLUSION: The results indicated that the inserted human DNA may be responsible for suppression of metastatic phenotype of mouse lung adenocarcinoma cells.

Adenocarcinoma↗
PubMed1996

Cyclosporine protects glomeruli from FSGS factor via an increase in glomerular cAMP.

Cyclosporine (CsA) administration to patients with recurrent focal segmental glomerulosclerosis (FSGS) after transplantation results in remission of proteinuria. We have shown that sera from patients with recurrent FSGS can increase the glomerular albumin permeability (Palbumin) and that increase in glomerular cAMP levels can alter the permeability characteristics of glomeruli in vitro. The purpose of this study was to determine if the increased glomerular levels of cAMP were related to the protective effects of CsA on an increase in Palbumin by FSGS sera. Glomeruli from Sprague-Dawley rats following intraperitoneal administration of CsA (25 mg/kg/day), cremophore (25 mg/kg/day), or saline for 5 days were incubated with 1:50 dilution of serum from three FSGS patients or with pooled normal human serum prior to calculation of Palbumin. Glomerular cAMP was measured by radioimmunoassay. Glomerular ultrastructural changes were assessed by transmission electron microscopy (TEM). Serum from three FSGS patients markedly increased Palbumin of glomeruli from saline or cremophore treated rats (saline, 0.68+/-0.08; 0.72+/-0.07; 0.70+/-0.07; and cremophore, 0.79+/-0.05; 0.81+/-0.02; 0.79+/-0.01; n=25 glomeruli in each group). In contrast Palbumin of glomeruli from CsA treated rats was not increased by any of the three FSGS sera tested (0.03+/-0.02; 0.04+/-0.05; 0.02+/-0.07, n=25 glomeruli in each group). Glomerular cAMP (pmol/mg of protein) increased 5 fold in CsA treated rats (328+/-26; 5 rats) compared with cremophore or saline treated rats (87+/-24 and 65+/-23, P<0.01; 5 rats in each group). The glomerular basement membrane appeared to be thickened and the lamina densa had an irregular appearance after treatment with CsA. No ultrastructural changes of glomerular epithelial or endothelial cells were evident. We conclude that CsA may have a direct protective effect on the glomerular filtration barrier in FSGS. We postulate that increased levels of glomerular cAMP by CsA may play an important role in protecting the glomerular Palbumin effect of the FSGS factor and may contribute to remission of proteinuria in FSGS patients.

Albumins↗
PubMed1996

3,3'-Diindolylmethane induces apoptosis in human cancer cells.

3,3'-Diindolylmethane is a dimer of indole-3-carbinol formed both in vivo and in vitro. In this study, human cancer cells MCF-7 (with wild-type p53), T47-D (mutant p53), and Saos-2 (deficient in p53 gene), were used to examine the anticancer activities of 3,3'-diindolylmethane. The dose-dependent growth inhibitory effect was found in all these cell lines. Exposure of the cells to 50 microM solution of 3,3'-diindolylmethane for 48 h, apoptosis (programmed cell death) was evidenced by the characteristic morphology of cell nuclei under fluorescence microscope and the DNA "ladder" in agarose gel electrophoresis. The percentage of apoptotic cells in each cell line was found to be 12% for MCF-7, 14% for T47D and 13% for Saos2 cells. Exposure of MCF-7 cells to 100 microM 3,3'-diindolylmethane for 24 h, 19% of apoptotic cells were detected by flow cytometry analysis. The lowest dose required for induction of apoptosis in MCF-7 cells was found to be 10 microM after 72 h incubation. Western blot showed that wild-type p53 protein was unchanged after MCF-7 cells had been exposed to 50 microM 3,3'-diindolylmethane for 8 h. This study provides evidences that 3,3'-diindolylmethane induces apoptosis in human cancer cells and that the induction of apoptosis is independent of p53 pathway.

Anticarcinogenic Agents↗
PubMed1996

A plant viral coat protein RNA binding consensus sequence contains a crucial arginine.

A defining feature of alfalfa mosaic virus (AMV) and ilarviruses [type virus: tobacco streak virus (TSV)] is that, in addition to genomic RNAs, viral coat protein is required to establish infection in plants. AMV and TSV coat proteins, which share little primary amino acid sequence identity, are functionally interchangeable in RNA binding and initiation of infection. The lysine-rich amino-terminal RNA binding domain of the AMV coat protein lacks previously identified RNA binding motifs. Here, the AMV coat protein RNA binding domain is shown to contain a single arginine whose specific side chain and position are crucial for RNA binding. In addition, the putative RNA binding domain of two ilarvirus coat proteins, TSV and citrus variegation virus, is identified and also shown to contain a crucial arginine. AMV and ilarvirus coat protein sequence alignment centering on the key arginine revealed a new RNA binding consensus sequence. This consensus may explain in part why heterologous viral RNA-coat protein mixtures are infectious.

Alfalfa mosaic virus↗
PubMed1996

The nucleotide sequence of hydrangea mosaic virus RNA 3 exhibits similarity with the RNA 3 of tobacco streak virus.

The complete nucleotide sequence of the RNA 3 of hydrangea mosaic virus (HdMV) was determined. It consists of 2268 nucleotides and contains two open reading frames (ORF). ORF 1 encodes for a putative translation product of 293 amino acids which shared 64.9% identity with the 3a protein of tobacco streak virus (TSV). ORF 2 encodes for a putative translation product of 220 amino acids which shared 54.2% identity with the coat protein of TSV. The relationship between the proteins of HdMV and the corresponding proteins of ilarviruses other than TSV was more distant. No zinc-finger-like motif was found in the coat protein of HdMV but the N-terminus of the protein was rich in basic amino acids. Both terminal, non-coding regions of HdMV RNA 3 contained repeated sequences with corresponding homologous fragments in the RNA 3 of TSV. On the basis of the similarities between HdMV and TSV that we detected, we propose that HdMV be included in subgroup 1 of the genus Ilarvirus together with TSV.

Amino Acid Sequence↗