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Biomedical subjects

B Liang

Publications and source records attributed to B Liang.

At least 55 records · Page 3Linked to original sources
PubMed1999

Prevention of immune dysfunction and vitamin E loss by dehydroepiandrosterone and melatonin supplementation during murine retrovirus infection.

Female C57BL/6 mice infected with the LP-BM5 leukaemia retrovirus developed murine acquired immune-deficiency syndrome (AIDS). Dehydroepiandrosterone (DHEA) and melatonin (MLT) modify immune dysfunction and prevent lipid peroxidation. We investigated whether DHEA and MLT could prevent immune dysfunction, excessive lipid peroxidation, and tissue vitamin E loss induced by retrovirus infection. Retrovirus infection inhibited the release of T helper 1 (Th1) cytokines, stimulated secretion of Th2 cytokines, increased hepatic lipid peroxidation, and induced vitamin E deficiency. Treatment with DHEA or MLT alone, as well as together, largely prevented the reduction of B- and T-cell proliferation as well as of Th1 cytokine secretion caused by retrovirus infection. Supplementation also suppressed the elevated production of Th2 cytokines stimulated by retrovirus infection. DHEA and MLT simultaneously reduced hepatic lipid peroxidation and prevented vitamin E loss. The use of DHEA plus MLT was more effective in preventing retrovirus-induced immune dysfunction than either DHEA or MLT alone. These results suggest that supplementation with DHEA and MLT may prevent cytokine dysregulation, lipid oxidation and tissue vitamin E loss induced by retrovirus infection. Similarly, hormone supplementation also modified immune function and increased tissue vitamin E levels in uninfected mice.

Animals↗
PubMed1999

[Clinical study on preventive effect of taozhi zhipu mixture on postoperative intestinal adhesion].

OBJECTIVE: To study the clinical effect of Taozhi Zhipu Mixture (TZM) in preventing postoperative intestinal adhesion. METHODS: Three hundred and ninety-six patients who had received abdominal operation were randomly divided into the treated group (188 cases) and the control group (208 cases). Same treatment was given to both groups excepting that the treated group received TZM orally or by nasogastric tube. The time of borborygmus recovering and first passing of flatus-defecation after operation was recorded. Patient's gastro-intestinal motion was observed by isotope tracing with I131 capsule. The frequency and intensity of borborygmus were measured by a tracer. All patients had been followed up for 2-3 years. RESULTS: The recovery of borborygmus, the first passing of flatus-defecation were much earlier, the I131 capsule passed gastro-intestinal tract more quickly, and tracer showed higher frequency and intensity of borborygmus in the treated group than those in the control group. Follow-up study also showed the treated group was better than the control group in the non-adhesion rate and the total effective rate (P < 0.05). CONCLUSION: TZM has good effect on stimulating postoperational gastro-intestinal peristalsis and preventing the occurrence of postoperational intestinal adhesion.

Adolescent↗
PubMed1999

[Experimental study on antitumor activity of the root of Eurphorbia helioscopia in vivo].

Previous studies showed EWE could strongly inhibit the proliferation of tumor cells in vivo. Experimental results also showed that EWE had antitumor effect in S180-bearing mice and H22-bearing mice and prolonged life-span in S180-bearing mice in this paper, Furthermore, it was found that EWE could improve the immune function of S180-bearing mice. Therefore EWE can be considered as a potent antitumor herb.

Animals↗
PubMed1999

[Antitumor activity of the root of Euphorbia helioscopic in vitro].

Antitumor activity of the aquatic extract the root of Euphorbia helioscopia L (EWE) in Vitro were studied. Viable cells count, MTT staining and colonal formation assays of three kinds of cancer cells were used to assess the antitumor activity. Determined by viable cells count, the IC50 values of EWE against 7721, Hela, MKN-45 cells were 1.26, 1.98, 1.72 mg/ml respectively (72 h). Determined MTT staining, the IC50 values EWE against 7721, Hela, MKN-45 cells were 1.43, 1.67, 0.97 mg/ml. Determined by colonal formation, the inhibition rate of EWE (4 mg/ml) against 7721, Hela, MKN-45 cells were 59.8%, 66.4%, 70.5%. The results indicated that EWE had obvious antitumor activity.

Antineoplastic Agents, Phytogenic↗
PubMed1998

The effect of chronic retrovirus infection and immune dysfunction on the P-450-mediated activation of acetaminophen in mouse liver microsomes.

Acute viral infection has long been recognized to down-regulate cytochrome P-450 enzymes and subsequently to result in changes in the pharmacological and toxicological responses to xenobiotics. In our previous research, chronic retrovirus infection induced by inoculating a susceptible strain of mice with LP-BM5 murine leukaemia virus (MuLV) was found to suppress acetaminophen (APAP) induced liver injury. In the present study, we aimed to examine the influence of chronic retrovirus infection and its associated immune dysfunction on the activities of a number of cytochrome P-450 isozymes and the P-450-mediated activation of APAP in mouse liver microsomes. Liver microsomes prepared from female C57BL/6 mice at 8 and 16 weeks after LP-BM5 MuLV inoculation as well as from age-matched controls were used in the study. The catalytic activities of the cytochrome P-450 isozymes 1A family and 2E1, catalysts for the activation of APAP, were measured in different microsomal preparations using O-dealkylation of alkoxyresorufin homologues and oxidation of p-nitrophenol, respectively, as the metabolic markers. The formation of the reactive APAP metabolite trapped as glutathione conjugate in the microsomal preparations was also determined. We demonstrated that there were variable changes in total hepatic P-450 levels and in the activities of a number of P-450 isozymes in animals with chronic retrovirus infection and immune dysfunction. Such changes seemed to be dependent on the stage of the disease and to have resulted in increases or minimal changes in the rate of APAP activation in hepatic microsomes collected from this animal model. This suggests that the P-450-mediated activation of APAP was not down-regulated in animals with chronic retrovirus infection. Enhanced elimination of APAP by detoxification metabolic pathways is more likely to be responsible for the increased resistance to APAP-induced hepatotoxicity observed in our previous research in animals with chronic retrovirus infection.

Acetaminophen↗
PubMed1998

Skeletal muscle regulatory proteins enhance F-actin in vitro motility.

Using an in vitro motility assay, we have investigated the effects of rabbit skeletal muscle regulatory proteins, troponin and tropomyosin, on the gliding of F-actin filaments or F-actin filaments containing these regulatory proteins. We demonstrate that Ca2+ does not affect the motility of F-actin gliding on HMM, but does in the presence of skeletal muscle tropomyosin and troponin. We conclude that Ca2+ affects motility through troponin because, like F-actin, F-actin-Tm filaments show no Ca(2+)-dependence to their gliding speeds. Furthermore, there is a large enhancement of the gliding speed (about 75%) in the presence of skeletal muscle tropomyosin, troponin + saturating Ca2+ over that seen with F-actin filaments. This enhancement is not due to the action of tropomyosin alone as skeletal muscle tropomyosin without troponin enhances the speed little (about 5%) over that of F-actin. Thus troponin confers Ca2+ sensitivity to the motility and, additionally, potentiates motility greatly along with tropomyosin in the presence of saturating Ca2+. When [HMM] is varied, the decline in speed of F-actin seen at low HMM density is changed little by tropomyosin in the F-actin-Tm filaments. These data show that the skeletal regulatory proteins interact with F-actin to enhance the interaction with HMM particularly in the presence of troponin and saturating Ca2+ and enhance the gliding speed in the in vitro motility assay as they potentiate the ATPase activity in the isolated proteins. This enhancement of speed in the motility assay cannot be ascribed to tropomyosin alone.

Actins↗
PubMed1998

Injection of T-cell receptor peptide reduces immunosenescence in aged C57BL/6 mice.

Previous studies established that retrovirally infected young mice produced large amounts of autoantibodies to certain T-cell receptor (TCR) peptides whose administration diminished retrovirus-induced immune abnormalities. C57BL/6 young (4 weeks) and old (16 months) female mice were injected with these same synthetic human TCR V beta 8.1 or 5.2 peptides. Administration of these autoantigenic peptides to old mice prevent immunosenescence, such as age-related reduction in splenocyte proliferation and interleukin-2 (IL-2) secretion. TCR V beta peptide injection into young mice had no effect on T- or B-cell mitogenesis and IL-4 production while modifying tumour necrosis factor-alpha (TNF-alpha), IL-6, and interferon-gamma (IFN-gamma) secreted by mitogen-stimulated spleen cells. TCR V beta injection also retarded the excessive production of IL-4, IL-6 and TNF-alpha induced by ageing. These data suggest that immune dysfunction and abnormal cytokine production, induced by the ageing process, were largely prevented by injection of selected TCR V beta CDR1 peptides.

Aging↗
PubMed1998

Modulation of cytokine production by dehydroepiandrosterone (DHEA) plus melatonin (MLT) supplementation of old mice.

Tissue levels of the antioxidants melatonin (MLT) and dehydroepiandrosterone (DHEA) decline with age, and this decline is correlated with immune dysfunction. The aim of the current study is to determine whether hormone supplementation with MLT and DHEA together would synergize to reverse immune senescence. Old (16.5 months) female C57BL/6 mice were treated with DHEA, MLT, or DHEA + MLT. As expected, splenocytes were significantly (P < 0.05) higher in old mice as compared to young mice. DHEA, MLT, and DHEA + MLT significantly (P < 0.005) increased B cell proliferation in young mice. However, only MLT and DHEA + MLT significantly (P < 0.05) increased B cell proliferation in old mice. DHEA, MLT, and DHEA + MLT help to regulate immune function in aged female C57BL/6 mice by significantly (P < 0.05) increasing Th1 cytokines, IL-2, and IFN-gamma or significantly (P < 0.05) decreasing Th2 cytokines, IL-6, and IL-10, thus regulating cytokine production. DHEA and MLT effectively modulate suppressed Th1 cytokine and elevated Th2 cytokine production; however, their combined use produced only a limited additive effect.

Animals↗
PubMed1998

Evaluation of left ventricular function with cine magnetic resonance four chamber/multiple slice multiple phase sequence.

OBJECTIVE: To investigate the value of cine magnetic resonance(MR) in determination of cardiac function by using four chamber/multiple slice multiple phase (4CH/MSMP) sequence. METHODS: In 18 healthy subjects, several indices of left ventricular function were measured by using cine MR 4CH/MSMP sequence, and the correlation of the results was compared with ultrasound cardiography by t test. RESULTS: In the measurement of left ventricular short diameter, left ventricular posterior wall thickness, internal ventricular septum thickness, left ventricular end diastolic and end systolic volume, the values of cine MR 4CH/MSMP sequence correlated well with those of echocardiography. The gamma value was between 0.88 and 0.99. CONCLUSION: The cine MR 4CH/MSMP sequence may be considered an important noninvasive modality for accurate assessment of cardiac function.

Adult↗
PubMed1998

[Relationship between catalase activity, KatG gene and isoniazid-resistance in M. tuberculosis].

OBJECTIVE: To investigate the relationship between catalase activity, KatG gene, gene mutation and INH-resistance in M. tuberculosis. METHOD: Catalase activities in 58 M. tuberculosis isolates were tested, and KatG gene mutations were detected further by PCR-SSCP. RESULT: None of INH-sensitive isolates lacked KatG sequences and all expressed catalase. 8(25%) INH-resistant isolates did not express catalase and 3(10%) lacked KatG gene, most of which were strains of high levels of resistance (MIC > 50 micrograms/ml). 8 INH-resistant isolates were analyzed further by PCR-SSCP and all were found to have KatG gene mutation. CONCLUSION: These findings indicated that lacking of catalase activity and KatG gene deletion occurred mainly in those highly INH-resistant strains, gene mutation other than complete deletion of KatG gene may be the major mechanism of INH-resistance.

Antitubercular Agents↗
PubMed1998

[Application of the sphygmogram in evaluation of pilots' cardiovascular function in resting condition].

With the purpose of exploring a new method for aerospace medical monitoring, a newly developed method--sphygmogram was used in 169 pilots. The results showed that these pilots could be divided into three types by the features of their resting sphygmogram. Among them, with respect to their cardiovascular function, 71 (about 42%) were "completely normal", 79 were "essentially normal", and 19 had some changes in cardiovascular function. It is considered that the status of cardiovascular function of the pilots can be distinguished with the newly developed method of sphygmogram. It suggests that it is important to make dynamic observations of pilots' cardiovascular function and strengthen the medical care for those who show certain changes in their cardiovascular function as revealed by the sphygmogram.

Adult↗
PubMed1998

[Study on the supercritical-CO2 fluid extraction of Prunus mandshurica oils].

The paper reported technological study on extracting Prunus mandshurica oils by supercritical-CO2 fluid, mainly researched the influence of pressure, temperature, time and flow rate of CO2 on the oil yield, determined optimum technology of extracting the oils, compared the oils from SFE-CO2 and traditional technology.

Carbon Dioxide↗
PubMed1997

Involvement of host factors in transcription from baculovirus very late promoters -- a review.

The baculovirus expression vector system has emerged as the system of choice for the expression of a number of heterologous genes of both prokaryotic and eukaryotic origin. This system utilizes the baculovirus very late, hyperactive polyhedrin and p10 promoters to drive the transcription of foreign genes. Regulation of transcription from these promoters is presently not well understood even though a number of viral gene products that may be important for transcription have been identified. Fresh insight into host-virus interactions during baculovirus pathogenesis is now offered by the identification of insect host factors that interact with transcriptionally essential motifs of these promoters as well as cis-acting enhancer-like elements upstream from the promoter.

Base Sequence↗
PubMed1997

Clinical significance of alpha(v)beta3 integrin and intercellular adhesion molecule-1 expression in cutaneous malignant melanoma lesions.

Several lines of experimental evidence in in vitro and animal model systems suggest that the integrin alpha(v)beta3 plays a role in the tumorigenicity of human melanoma cells and that the blocking of alpha(v)beta3 ligand binding can inhibit tumor progression. However, there is only scanty information about the role of alpha(v)beta3 in malignant melanoma in a clinical setting. Therefore, in the present study, we have analyzed the distribution in lesions of melanocyte origin and in normal tissues of the alpha(v) integrin subunit and of the alpha(v)beta3 complex and their association with histopathological and clinical parameters of malignant melanoma. We have used as probes the monoclonal antibodies (mAbs) TP36.1 and VF27.263.15, which we have shown with a combination of serological and immunochemical assays to be specific for the alpha(v) subunit and for the alpha(v)beta3 complex, respectively. In immunohistochemical assays, mAb TP36.1 stained both benign and malignant lesions of melanocyte origin. In contrast, the reactivity of mAb VF27.263.15 was restricted to malignant lesions. Both mAbs displayed differential reactivity with primary melanoma lesions of different histotypes because they stained about 50% of acral lentiginous melanoma and superficial spreading melanoma lesions, at least 80% of nodular melanoma lesions, and none of the uveal melanoma lesions tested. Both mAbs TP36.1 and VF27.263.15 stained about 60% of lymph node metastases and 80% of cutaneous metastases. Expression of the alpha(v)beta3 complex in melanocytic lesions resembles that of intercellular adhesion molecule-1 (ICAM-1) in several respects: (a) both are expressed in a significantly (P < 0.004) larger proportion of malignant than of benign lesions; (b) expression of both molecules in primary melanoma lesions is significantly (P < 0.05) associated with lesion thickness; and (c) expression of both molecules in primary lesions from patients with stage I melanoma is significantly (P < 0.05) associated with an increased probability of disease recurrence following surgical excision. alpha(v)beta3 and ICAM-1 in primary melanoma lesions complement each other in predicting the outcome of the disease, because the association with prognosis was enhanced when primary lesions were stained by both anti-alpha(v)beta3 mAb VF27.263.15 and anti-ICAM-1 mAb CL203.4 or by neither mAb. Because alpha(v)beta3 has been suggested as a potential target of immunotherapy, its distribution in normal tissues was investigated. alpha(v)beta3 expression is restricted because it was only detected in ductal epithelium of parotid glands, thyrocytes, basal glands of the stomach, colonic and rectal epithelium glomeruli, Bowman's capsules and proximal and distal tubules of kidneys, and endometrial epithelium. These findings suggest that renal function will be a critical clinical parameter to monitor in therapies of malignant diseases relying on systemic administration of anti-alpha(v)beta3 mAb.

Antibodies, Monoclonal↗
PubMed1997

Loss of heterozygosity in human ovarian cancer on chromosome 19q.

Abnormalities in the function of oncogenes and tumor suppressor genes have been associated with many human malignancies. The recognition of sites of loss of heterozygosity (LOH) has led to the identification of such genes. We previously reported that abnormalities of mRNA expression of ERCC1 and ERCC2 may be characteristic of epithelial ovarian carcinoma and brain tumors. This led to an investigation of chromosome 19q13.2-q13.4 which contains these DNA repair genes. A 7-Mb region was analyzed using six microsatellite repeats. Loss of heterozygosity has been identified in 53% (8/15) of cases at marker D19S246 which lies in a 2-Mb segment between HRC and KLK1. The genetic material both centromeric and telomeric to the region of loss was conserved. This area is telomeric to three DNA repair genes where LIG1 is 1-Mb centromeric and ERCC1 and ERCC2 are 3.5- and 4.0-Mb centromeric, respectively. These findings represent the first report of a biologically significant rate of LOH on chromosome 19q13.2-q13.4 in human ovarian carcinoma.

Adolescent↗
PubMed1997

Modulation of immune dysfunction during murine leukaemia retrovirus infection of old mice by dehydroepiandrosterone sulphate (DHEAS).

Ageing, leukaemia and acquired immune deficiency syndrome (AIDS) are conditions with dysregulated cytokine production. As dehydroepiandrosterone sulphate (DHEAS) restored normal cytokine production in old mice its effects on retrovirally infected old mice were investigated. Retrovirus infection and ageing-induced immune dysfunction. Murine retrovirus-infected old C57BL/6 female mice consumed 0.22 or 0.44 microgram of DHEAS/mouse/day beginning 2 weeks postinfection for 10 weeks. DHEAS largely prevented the retrovirus-induced reduction in T-cell and B-cell mitogenesis. DHEAS supplement prevented loss of cytokines [interleukin-2 (IL-2) and interferon-gamma] secretion by mitogen-stimulated splenocytes representing T helper 1 (Th1) cell phenotypes. It also suppressed the retrovirus-induced, excessive production of cytokines (IL-6 and IL-10) by Th2 cells. The highest dose of DHEAS reduced IL-6 production by splenocytes from uninfected old mice by 75% while increasing their IL-2 secretion by nearly 50%. Thus immune dysfunction induced by ageing, even when exacerbated by murine retrovirus infection, was largely prevented by DHEAS.

Aging↗
PubMed1997

Melatonin, immune modulation and aging.

Melatonin is a hormone secreted by the pineal gland in response to photoperiods and influences many important biological processes. For one, Melatonin has been shown to produce resistance to cancer and infectious diseases in aged animals. Studies in animals have demonstrated melatonin-related mechanisms of action on immunoregulation. Additionally, melatonin has been successfully used in humans, along with interleukin-2, as a treatment of solid tumors. In vivo and in vitro studies show melatonin enhances both natural and acquired immunity in animals. Despite all of this intriguing evidence, melatonin's mechanism of action on the immune system is only partially defined. It does, however, appear to act through lymphocyte receptors, and perhaps, receptors on other immune tissues, to modulate immune cells. In order to understand immunomodulation and anti-cancer effects, information on melatonin and it's interactions with other endocrine hormones are summarized.

Aging↗