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Biomedical subjects

C Ji

Publications and source records attributed to C Ji.

At least 91 records · Page 5Linked to original sources
PubMed1993

[The role of OLS in peripheral acupuncture analgesia in arthritic rats].

Our previous work has shown that opiate-like substance (OLS) is involved in the central mechanism of acupuncture analgesia (AA) in the arthritic rats. In this paper, the role of OLS in peripheral mechanism of AA is further studied. Twenty four hours after a subcutaneous injection of Freund's adjuvant into the right ankles, acute arthritis with typical symptoms developed in all the rats. Following needling at Huantiao points for 10 minutes, the pain threshold (PT) was raised by 42.3% (P < 0.05) in the inflamed ankles and by 5.6% in the non-inflamed ones. When systemically administered a dose of 250 and 100 micrograms, naloxone (Nx) could completely and partially (49.6%) block AA respectively. While locally injected a dose of 100 micrograms even 20 micrograms, Nx could completely antagonize AA. After systemic administration of morphine (10, 5.0, 2.5, 1.25 mg/kg), PT rise was dose-related, and PT was raised by 86.5 +/- 22.7% in the affected ankles and by 32.9 +/- 14.9% in the normal ankles at 5 mg/kg in dose. It is evident that the opiate receptors in the inflamed area should by sensitized. These results demonstrate that activation of endogenous opiate system may also be involved in the peripheral AA. Acupuncture may enhance the release of peripheral OLS which can act at the sensitized opiate receptors, leading to more potent analgesic effect in the inflamed area.

Acupuncture Analgesia↗
PubMed1993

[The effect of stimulating the auricular liver-gall point on the size of gallbladder of the rabbit].

After stimulating the auricular liver-gall point of rabbit with electrode. We observed marked contraction of gallbladder. Only one minute after stimulation, the contraction began. About ten minutes after stimulation the contraction was marked and the contraction lasted for 30-40 minutes. The average product of the length and width of gallbladder (15-25 minutes after stimulation) is markedly smaller than that of control (pre-stimulation). This result proves the liver-gall point of rabbit corresponds with its internal organ-gallbladder. The result also present a theoretic basis for clinical therapy of press over the auricular liver-gall point induced the excretion of gallstones.

Acupuncture Points↗
PubMed1993

[The changes in the levels of angiotensins and angiotensin converting enzyme and effects of captopril in patients with hypoxic pulmonary hypertension].

The levels of angiotensin I, II (ATI, II) and angiotensin converting enzyme (ACE) were measured in 28 patients with hypoxic pulmonary hypertension and 23 normal individuals. The effects of captopril were observed in 8 of 28 patients. The results showed that the average level of ATII in the patients was significantly higher than that in normal control (P < 0.05), but the average level of ACE in the patients was significantly lower than that in the controls (P < 0.05). In 8 patients, after the use of captopril, an ACE inhibitor, for two weeks, the levels of ATII, ACE and mean pulmonary arterial pressure (mPAP) were markedly decreased (P < 0.05). But the other 20 patients treated with antibiotics, antiasthmatics, diuretics and oxygen therapy for two weeks did not show any alterations in the levels of ATII, ACE and mPAP.

Aged↗
PubMed1992

Oxygen radical-dependent epoxidation of (7S,8S)-dihydroxy-7,8-dihydrobenzo[a]pyrene in mouse skin in vivo. Stimulation by phorbol esters and inhibition by antiinflammatory steroids.

(7S,8S)--Dihydroxy--7,8--dihydrobenzo[a]pyrene ((+)-BP-7,8-diol) is epoxidized to (7S,8R)-dihydroxy-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene ((+)-syn-BPDE) by cytochrome P-450 isoenzymes and to (7S,8R)-dihydroxy-(9R,10S)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene ((-)-anti-BPDE) by peroxyl free radicals. 32P postlabeling analysis of the diastereomeric BPDE-DNA adducts was used to investigate the pathways of (+)-BP-7,8-diol oxidation in mouse skin in vivo. The pattern of deoxynucleoside 3',5'-bisphosphate adducts in epidermal scrapings from female CD-1 mice indicated that cytochrome P-450 was the major oxidant. Similar results were obtained when the tumor-promoting phorbol ester tetradecanoylphorbolacetate (TPA) was coadministered with (+)-BP-7,8-diol. However, when animals were pretreated with TPA 24 h before coadministration of TPA and (+)-BP-7,8-diol, the pattern of BPDE-DNA adducts indicated that peroxyl radicals made a major contribution to (+)-BP-7,8-diol epoxidation. Peroxyl radical-dependent epoxidation was maximal when the time between the two TPA administrations was 24-72 h. No increase in (-)-anti-BPDE-DNA was observed when the non-tumor-promoting phorbol ester 4-O-methyl-TPA was substituted for TPA. The calcium ionophore A23187 stimulated peroxyl radical generation when substituted for the first, but not the second, TPA treatment. The antiinflammatory steroid fluocinolone acetonide inhibited (-)-anti-BPDE-DNA adduct formation when coadministered with the first but not the second TPA treatment. These findings demonstrate the existence of two independent pathways of metabolic activation of (+)-BP-7,8-diol in mouse epidermis, one dependent on cytochrome P-450 and the other dependent on peroxyl free radicals. The results also suggest that repetitive topical administration of tumor-promoting phorbol esters remodels epidermal metabolism leading to a significant increase in free radical generation.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1991

Positional specificity for methyl-n-amylnitrosamine hydroxylation by cytochrome P-450 isozymes determined with monoclonal antibodies.

Inhibitory monoclonal antibodies (MAbs) were used to determine the contribution of epitope-specific cytochrome P-450 isozymes in rat liver microsomes to hydroxylation of the esophageal carcinogen methyl-n-amylnitrosamine. These P-450-catalyzed reactions form 2-, 3-, 4-, and 5-hydroxymethyl-n-amylnitrosamine, formaldehyde (demethylation), and pentaldehyde (depentylation). With uninduced microsomes from male rats, MAb 1-68-11 inhibited 4-hydroxylation by 73% and demethylation by 46%. This indicated the major contribution of constitutive male-specific P-450 IIC11 to the metabolism. Inhibition studies with MAbs 2-66-3 and 1-91-3 indicated that P-450 IIB1 contributed 19% and IIE1 35% to demethylation. With uninduced microsomes from females, MAb 1-68-11 produced similar inhibitions to those in male rats, indicating that female-specific P-450 IIC12 (which is closely related to IIC11) also catalyzed 4-hydroxylation and demethylation. With microsomes from 3-methylcholanthrene-induced male rats, P-450 IA1 and/or IA2 were responsible for 60% of 3-hydroxylation and 40% of depentylation. With microsomes from phenobarbital-treated rats, P-450 IIB1 and IIB2 catalyzed all 6 reactions but especially 4-hydroxylation and depentylation, which were 50-75% inhibited by MAb 2-66-3. Microsomes from Aroclor-induced males behaved as if they were induced by both 3-methylcholanthrene and phenobarbital. After treatment with isoniazid (a P-450 IIE1 inducer), inhibition by MAb 1-91-3 indicated a 45% contribution of P-450 IIE1 to demethylation, and both P-450 IIE1 and IIB1 (or IIB2) appear to have been induced. A major finding with uninduced microsomes was the high specificity of MAb 1-68-11 for inhibiting 4-hydroxylation, indicating that P-450 IIC11 and IIC12 catalyzed most of this omega-1-hydroxylation. In microsomes from induced rats, the MAb inhibitions showed the role of the induced P-450 IA1 (or IA2), IIB1 (or IIB2), and IIE1 in methyl-n-amylnitrosamine hydroxylation at different positions, as well as the presence of P-450 IIC11. This study illustrates the usefulness of inhibitory MAbs for defining the contribution of individual P-450s to position-specific metabolism.

Animals↗
PubMed1991

[Studies of pickled vegetables and cause of esophageal cancer in Linxian. II. Determination of nitrosamines and their precursors].

Pickled vegetables are daily food consumed in the high-risk areas for esophageal cancer in China. We analyzed the nitrosamine content of Linxian pickles by GC/TEA and found that trace amounts of six nitrosamines (NDMA, NDEA, NMBA, NMAMBA, NDPA, NPYR) were present, with the highest concentrations being NDMA and NDEA (1.7 and 1.9 micrograms/kg wet weight respectively). The average level of nitrosamine precursors, such as nitrate (111.22 mg/L), nitrite (0.152 mg/L) and secondary amines (4.223 mg/L), in pickled vegetables were determined, and their pH values ranged from 3 to 5.

Diethylnitrosamine↗
PubMed1991

Use of monoclonal antibodies to identify cytochrome P450 isozymes in rat liver microsomes that hydroxylate N-nitrosomethylamylamine at each of six positions.

Inhibition of enzyme activity by monoclonal antibodies (MAbs) was used to indicate which cytochrome P450 isozymes in Sprague-Dawley rat liver microsomes catalyse hydroxylation of the oesophageal carcinogen N-nitrosomethyl-n-amylamine (NMAA) to give 2- to 5-hydroxy-NMAA (HO-NMAA), formaldehyde and pentaldehyde. Liver microsomes (0.3-0.6 mg protein) were incubated (15 min, 23 degrees C) with 0.4 mg MAb and, after adding NMAA to 6 mM, incubated for 20 min at 37 degrees C. Mixtures were analysed for HO-NMAAs by gas chromatography-thermal energy analysis and for aldehydes by high-performance liquid chromatography of their 2,4-dinitrophenylhydrazones. The percentage inhibition by each MAb indicates the percentage metabolism by the corresponding P450 isozyme(s). These results indicate that the MAb to P450 IIB1 cross-reacts with P450 IIE1 and that the MAb to male-specific constitutive IIC11 cross-reacts with female-specific IIC12. Taking this into account, the main results were as follows. With uninduced male microsomes, 4-hydroxylation was catalysed mainly by IIC11 and demethylation by IIC11 and IIE1. With uninduced female microsomes, P450s reacting with the MAb to IIC11 (probably mainly IIC12) were responsible for most of the 4-hydroxylation and demethylation. With 3-methylcholanthrene-induced male microsomes, most 3-hydroxylation and some depentylation were due to IA1 or IA2. With phenobarbital-induced microsomes, all six reactions, but especially 4-hydroxylation and depentylation, were largely due to IIB1. With Aroclor-induced microsomes, all six reactions were catalysed by IIB1 and IA1 or IA2. The role of P450 IIC11 in 4-(omega-1)-hydroxylation was striking.

Animals↗
PubMed1990

[Diagnostic value of transbronchial lung biopsy in diffuse or peripheral lung lesions].

The results of 102 cases of diffuse or peripheral lung lesions examined by transbronchial lung biopsy (TBLB), bronchial brushing (BB), and bronchial alveolar lavage (BAL) via fiberoptic bronchoscope, were reported. The positive diagnostic rate was 74.5% (76 cases). In lung cancer, the positive rate by means of BB was 77.1%, which was higher than that by TBLB (58.1%). In pulmonary tuberculosis, the positive rate by TBLB was 76.9%, higher than that by BAL fluid for identification of tubercle bacillus by culture (44.4%). If TBLB was combined with BB and BAL, the positive diagnostic rate would be further elevated. The data showed that if the size of the masses greater than or equal to 3cm in peripheral lung field on chest film, the possibility of lung cancer was greater than that of those less than 3cm. Most cases of localized infiltration in the lungs were caused by tuberculosis. But the diffuse lesions of the lungs were often caused by bronchiolo-alveolar carcinoma, adenocarcinoma, diffuse interstitial fibrosis of the lungs, silicosis, sarcoidosis, etc. By the careful study of the chest film and ascertainment of the exact locations of the pulmonary lesions there, we can carry out the TBLB and obtain a satisfactory specimen without any X-ray monitoring. In the present group of patients who underwent TBLB, one was complicated by haemorrhage (greater than 50ml) and two by pneumothorax, but all of them recovered promptly after proper management. By strick adherence to indication, adequate preoperative preparations and very careful performance of the procedure, the complications of TBLB could be reduced to minimum.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[The effect of laser irradiation on arthritis in rats].

Based on the analgesic effect of laser therapy in clinic, the effect of laser irradiation at acupoints on the experimental arthritis in rats was further observed. The experiments were carried out on Wistar rats, which were divided into three groups: The normal group (n = 6): without any treatment. The laser group (n = 8): 24 hours after an injection of Freund's adjuvant, the typical symptoms of acute arthritis (red, swelling, pain and hyperalgesia) occurred. Then transcutaneous irradiation with a low power Helium-neon laser (3 mw, 6328 A) at ipsilateral Kun-Lun point was applied ten minutes every day for five days. The control group (n = 8): with the same treatment as the laser group except laser irradiation. All the indexes, such as foot volume, pain score and pain threshold (Heat-leg-withdrawal latency, HWL and electric-shock vocalization, VOC) were measured every day. Comparing with the symptoms in the control group, the intensity of pain as measured on pain score and the swelling of the ankles (foot volume) were significantly reduced by laser irradiation (P less than 0.01), but the pain threshold (HWL and VOC) did not show any improvement in laser group. However, immediately after laser irradiation, the average pain threshold (VOC) was significantly raised (P less than 0.01). It is concluded that low power laser irradiation at local points can produce the relief from arthralgia and reduction in the swelling of ankles, and it can also produce instant analgesic effect in test of pain threshold (VOC).

Acupuncture Points↗
PubMed1990

[Application and evaluation of Beijing-Tianjing enamel adhesives in orthodontics].

Beijing-Tianjing enamel adhesive is a kind of composite resin adhesive which contains enamel loading agents. The bonding strength is high, the tensile strength and the shear strength are 113 kg/cm2 and 229 kg/cm2 respectively. 7,800 cases of many kinds of malocclusion were treated with the bonding fixed appliance for five years in Beijing Stomatological hospital. The results showed that the cure rate was 96.3%. The application and effectiveness were evaluated in this study. The application of TN-appliance bonded directly to the buccal tube bracket of molar without band was discussed.

Adhesiveness↗
PubMed1990

Oxidation of polycyclic hydrocarbons by oxygen radicals.

Dihydrodiolepoxides (BPDE) are reactive derivatives that appear to mediate the genotoxic effects of benzo[a]pyrene (BP) and several other polycyclic hydrocarbons. Their formation requires sequential epoxidation, hydration, and epoxidation steps. The first epoxidation step is catalyzed by cytochrome P-450 isoenzymes whereas the second is catalyzed by cytochromes P-450 and assorted species of oxygen radicals (in particular peroxyl radicals). The stereochemistry of epoxidation of the procarcinogen 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP-7,8-diol) is a useful tool with which to dissect the contributions of cytochrome P-450-dependent and independent pathways. [32P]-Postlabeling techniques were developed to analyze the diastereomeric composition of BPDE-deoxynucleoside-bis-phosphate adducts recovered from DNA of target tissues for BP tumorigenesis. Application of these techniques revealed that cytochrome P-450 is the major contributor to BPDE production in mouse skin in vivo. Following administration of BP or (+)-BP-7,8-diol to female CD-1 mice, only minor amounts of adducts derived from peroxyl radical epoxidation were detected. In contrast, pretreatment of the animals with the tumor promoter tetradecanoyl phorbol acetate (TPA) led to the formation of sizeable amounts of non-cytochrome P-450-dependent adducts following coincident administration of (+)-BP-7,8-diol with a second dose of TPA. The results demonstrate that although oxygen radicals appear to play a minor role in tumor initiation by BP, they may play a major role in tumor promotion by phorbol esters.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1989

Formation of hydroxy derivatives, aldehydes, and nitrite from N-nitrosomethyl-n-amylamine by rat liver microsomes and by purified cytochrome P-450 IIB1.

The metabolism was examined of the esophageal carcinogen N-nitrosomethylamylamine (NMAA) by liver microsomes and slices from adult male Sprague-Dawley rats. Hydroxylation at C-2 to C-5 of the amyl group to give stable hydroxy-NMAAs was studied by gas chromatography-thermal energy analysis to determine the products. Microsomal metabolism produced mainly 4-hydroxy-NMAA, proceeded optimally in 100 mM phosphate at pH 7.4, and showed no sex differences. Induction by phenobarbital (PB) and 3-methylcholanthrene produced effects which were similar in slices and microsomes, with PB inducing hydroxylation at all positions and 3-methylcholanthrene specifically inducing 3-hydroxylation by factors of 2- and 6-fold. Clofibrate and isoniazid treatments did not affect NMAA metabolism by liver slices. Aroclor-1254 strongly induced microsomal 2- and 3-hydroxylation. For 2- to 5-hydroxylation, Km values for uninduced microsomes were, respectively, 1.6, 1.2, 0.3, and 1.1 mM, with Vmax of 0.08, 0.26, 1.06, and 0.15 nmol/min/mg protein. With PB-induced microsomes, all 4 Km values were 0.4-0.7 mM. Liver microsomal production of nitrite and aldehydes from NMAA was determined colormetrically or (for pentaldehyde) by high-pressure liquid chromatography of the 2,4-dinitrophenylhydrazone. Uninduced microsomes produced nitrite, formaldehyde and pentaldehyde from 0.6 mM NMAA at rates that were, respectively, 0.15, 0.72, and 1.15 times that for 4-hydroxylation. PB especially induced depentylation, whereas 3-methylcholanthrene induced depentylation and denitrosation, but suppressed demethylation. A reconstituted system containing cytochrome P-450 IIB1 gave metabolite ratios similar to those in PB-induced microsomes. The results account for most of the possible primary metabolites of NMAA and demonstrate the selectivity for metabolism at each position.

Aldehydes↗
PubMed1987

Metabolism of the oesophageal carcinogen N-nitrosomethylamylamine: changes with age, clearance from blood and DNA alkylation.

Freshly excised rat oesophagus and other tissues metabolize N-nitrosomethyl-n-amylamine (NMAA) to 2-, 3-, 4- and 5-hydroxy-NMAA (HO-NMAA), and 3- and 4-oxo-NMAA. We examined the development of this metabolism in MRC-Wistar rats and Syrian hamsters. In rats, oesophagus showed maximum metabolism at nine days of age, and forestomach showed considerable metabolism at three days, but none in adults. In newborn hamsters, oesophagus showed 10.4%; and in three-day hamsters, forestomach showed 4.9% metabolism, despite low or no metabolism by the adult tissues. Clearance of NMAA (25 mg/kg) from rat blood had a half-life of 21 min. The blood also contained considerable amounts of 4-oxo- and 4-HO-NMAA. Incubation of adult oesophagus and liver slices with 3H-labelled NMAA produced DNA labelling, including labelled N7-and O6-methylguanine, with 14 times higher specific radioactivity in DNA from oesophagus than from liver. O6-Methylguanine was also measured by radioimmunoassay.

Aging↗
PubMed1986

Occurrence of nitroso compounds in fungi-contaminated foods: a review.

Dimethylnitrosamine (NDMA), diethylnitrosamine (NDEA), methylbenzylnitrosamine, and a new N-nitroso compound, N-3-methylbutyl-N-1-methylacetonylnitrosamine (NMAMBA), were found in cornbread that was inoculated with Fusarium moniliforme and underwent an incubation and the addition of a small amount of NaNO2. The carcinogenicity of NMAMBA was shown by the induction of forestomach carcinomas and liver tumors in mice and rats. Another new nitrosamine, N-2-methylpropyl-N-methylacetonyl nitrosamine, was isolated in millet and wheat flour after similar treatment. Some species of fungi not only can reduce nitrates to nitrites but also can increase the amount of secondary amines in the moldy foods and provide favorable conditions for the synthesis of nitrosamines. Some fungi may utilize primary amines to synthesize nitrosamines in appropriate culture mediums. Furthermore, the cornmeal may naturally contain trace amounts of nitrosamines, as detected by a gas chromatography/thermoenergy analyzer. Prolonged feeding of F. moniliforme-inoculated cornbread alone also induced the development of forestomach carcinoma in rats. This indicates the occurrence of potential carcinogens, perhaps certain Fusarium mycotoxins, in the moldy cornbread in addition to the carcinogenic nitrosamines. Another nitroso compound, Roussin red methylester (di-mu-methanethiolatotetranitrosodiiron) was found in pickled vegetables that are eaten daily in the Linxian (China) area. Roussin Red may provide NO-2 ions, which would react readily with secondary amines to form nitrosamines. Possibly this compound is a natural tumor promoter and is able to induce epithelial hyperplasia of the upper digestive tract and forestomach papilloma in treated mice. Also, trace amounts of NDMA, NDEA, and some other nitrosamines were found in the extract of pickled vegetables.

Animals↗