Biomedical subjects

B Y Chen

Publications and source records attributed to B Y Chen.

At least 37 records · Page 2Linked to original sources

PubMed1996

Enzyme-linked immunosorbent assay for detection of IgG against penicillins in children.

AIM: To establish an enzyme-linked immunosorbent assay (ELISA) for detection of IgG against penicillins and then investigate this antibody response in children. METHODS: Western blotting, ELISA, and hapten inhibition assay were used. RESULTS: Penicillins reacted with bovine serum albumin (BSA) to generate conjugate which was used as coating antigen (100 mg.L-1) in ELISA. A good correlation was found between absorbance (A) and dilutions of sample with a linear coefficient of 0.9918. Thirteen subjects who were clinically suspicious of penicillin allergy were tested for specific IgG by ELISA, 4 positive for benzylpenicillin, 1 for benzylpenicillin and piperacillin, and 3 for benzylpenicillin, piperacillin and ampicillin. CONCLUSION: An ELISA was successfully established and penicillin reactive IgG response in children was heterogeneous. IgG antibodies recognized benzylpenicillin molecule, degraded products and new antigenic determinant from conjugate. Cross reactions occurred among benzylpenicillin, ampicillin and piperacillin.

Child↗

PubMed1996

Benzylpenicillin induced specific non-IgE antibody response in mice.

AIM: To study whether or not the specific non-IgE antibody response in mice can be induced by benzylpenicillin in vivo. METHODS: Antibody response and antigenic cross reactions were determined by enzyme-linked immunosorbent assay (ELISA). Antigen molecules recognized by antibodies were tested by hapten inhibition assay. RESULTS: During d 1-d 50 after immunization, positive % of specific IgM, IgG, and IgA to benzylpenicillin were 100%, 50%-100%, and 17%-100%, respectively. IgM and IgG to benzylpenicillin also recognized ampicillin and piperacillin. The positive % of IgM and IgG to ampicillin were 23%-100% and 50%-100%, to piperacillin 43%-100% and 50%-100%, respectively. Aged benzylpenicillin showed an inhibitory effect on specific antibodies in a dose-dependent manner, and inhibitory % of specific IgM and IgG were 29%-87% and 29%-71%. However, freshly prepared benzylpenicillin had no effect. CONCLUSION: Specific non-IgE antibody response was successfully induced by benzylpenicillin in mice, in which the isotypes were mainly IgM and then IgG and IgA. Antibodies recognized degraded products, not benzylpenicillin molecule itself. Antigenic cross reactions occurred between benzylpenicillin, ampicillin, and piperacillin. Isotypes of antibodies responsible for cross reactions were mainly IgG and then IgM.

Animals↗

PubMed1995

Temperature induction of bacteriophage lambda mutants in Escherichia coli.

The paper presents temperature induction in Escherichia coli cells with phage lambda on the target-protein production and cell growth. Replicated lambda-DNA particles in the Q- and S- mutants remain naked for a longer time by preventing DNA packaging and cell lysis, and therefore the expression of the foreign genes is high. However, the parasitic infection of phage-lambda causes on significant losses of host cell viability in the induction phase. The temperature effects on cell growth and targeted-gene product formation were investigated. Gene amplification was found to be growth phase dependent for both Qam73 (Q mutation) and Sam100 (S mutation) mutants. Maximum induction occurs in the early exponential phase and under the optimal cell density. The total beta-galactosidase activity at this optimal induction condition increases roughly 8-10-fold with respect to that without thermal induction. To maximize the induction efficiency for the gene-product beta-galactosidase activity, several operating parameters were investigated. In this study, temperature induction is strongly dependent upon the population density of 'susceptible' cells at which time the temperature is shifted to 38-42 degrees C. This may be due to the 'threshold' population density to regulate the infection of lambda to hosts and control the productivity of target gene expression.

Bacteriophage lambda↗

PubMed1994

Annexin VI-binding proteins in brain. Interaction of annexin VI with a membrane skeletal protein, calspectin (brain spectrin or fodrin).

Identification of annexin VI-binding proteins is essential to elucidate the physiological functions of annexin VI. Here, we developed the methods to identify an annexin VI-binding protein and characterized the binding. Annexin VI bound to about 14 species of proteins in the whole homogenate of rat forebrain, when examined with 125I-annexin VI using blots of SDS-polyacrylamide gels. The binding was Ca(2+)-dependent and specific for phosphatidylserine (PS) and phosphatidic acid. A line of evidence indicates that the binding of annexin VI to its target proteins is a protein-protein interaction. One of annexin VI-binding proteins with M(r) 240,000 was enriched in the cytoskeletal fraction and was identified as calspectin (brain spectrin or fodrin). When the binding was examined with purified calspectin in the native state, the Ca2+ affinity (KCa) was 7.6 microM, and the affinity for annexin VI (Kd) was 68 nM. Annexin VI bound to beta subunit of calspectin, but not to alpha subunit. The binding site was localized to the NH2-terminal domain of beta subunit, which contains an actin-binding site and exhibits striking homology with the NH2-terminal regions of dystrophin and alpha-actinin. When the effect of annexin VI on the interaction between F-actin and calspectin was examined by low shear viscometry, annexin VI inhibited the F-actin cross-linking activity of calspectin in a Ca2+/PS-dependent manner. Cosedimentation assay showed that annexin VI dissociates calspectin from F-actin in the presence of Ca2+ and PS. These results suggest that annexin VI can dissociate and redistribute calspectin in a Ca2+/phospholipid-dependent manner under the plasma membrane and that annexin VI may be involved in the regulation of the membrane skeleton of neuronal cells in response to Ca2+.

Actins↗

PubMed1994

[Controlled observations on 65 infantile acute viral myocarditis treated with traditional and Western medicine].

A prospective study of 65 infantile acute viral myocarditis was done, they were divided into two groups, the first group mainly treated with Tong-Mai oral liquid, a TCM drug, the second group used general therapy with Mixture ATP as its main drug. The results showed that the effective rate of the 1st and 2nd group was 93.02% and 72.73% respectively; their symptoms and signs such as suffocation, fatigue, chest pain, improved in reducing the size of enlarged heart, the effective rate of EKG, particularly ST-T and various blocks, as well as in improving the function of left ventricular and abnormal systolic time interval (STI), the 1st group was better than that of 2nd one in all above-mentioned five aspects (P < 0.05-0.01). Therefore, it was assumed that therapy of activating the blood circulation to relieve stasis, the Tong-Mai oral liquid might be a good approach in treating infantile acute viral myocarditis.

Acute Disease↗

PubMed1994

[The effect of microinjection of AVP and AVP-antiserum into septal area on discharge activity of temperature-sensitive neurons in PO-AH of rabbits].

Arginine vasopress in (AVP) has been shown to have significant effects on thermoregulation. AVP-sensitive locus is located in the septal area of the limbic system. The present experiments were undertaken to investigate the effect of microinjecting AVP and AVP-antiserum into the septal area on the firing activity of temperature-sensitive neurons in preoptic-anterior hypothalamus (PO-AH) of rabbit. The results were as follows: (1) The firing rate of PO-AH warm-sensitive and cold-sensitive neurons were respectively increased and decreased by injection of AVP while that of temperature-insensitive neurons was unaffected. (2) Injection of AVP-antiserum decreased the firing rate of PO-AH warm-sensitive neurons but increased the firing rate of cold-sensitive neurons. (3) Injection of AVP increased the thermosensitivity of PO-AH warm-sensitive neurons and decreased the thermosensitivity of cold-sensitive neurons. The modulation action of AVP on PO-AH temperature-sensitive neurons was discussed.

Animals↗

PubMed1993

Levo-praziquantel versus praziquantel in experimental and clinical treatment of schistosomiasis japonica.

Levo-praziquantel is the left isomer of racemic praziquantel. Animal experiments showed that it is an active component of schistosomicidal activity, while dextro-praziquantel is almost ineffective. Clinical trials in three endemic areas of Schistosomiasis japonica indicated that the therapeutic efficacy of levo-praziquantel is superior to racemic praziquantel. Pharmacokinetic and pharmacodynamic activities of the stereoselectivity of praziquantel isomers (enantiomers) are discussed.

Animals↗

PubMed1993

[Hypotensive effect of dihydrolycorine].

Dihydrolycorine-HCL(DL) is a derivative of lycorine, an alkaloid isolated from Lycoris radiata Herb. DL iv 20, 40, and 80 mg.kg-1 lowered the mean arterial pressure in pentobar-bitone-anesthetized normotensive rats, cats, and conscious rats either normotensive or renovascular hypertensive. In pithed rats DL depressed the hypertensive effect of reaction to electric stimulation to the T7-9 segments of spinal cord. DL also depressed the hypertensive effect of phenylephrine. In rabbit aorta ring and rat anococcygeus muscle, DL antagonized the contractile effect of methoxamine, with pA2 values of 5.93 and 6.35, respectively. These results suggest that DL can block alpha 1-adrenoceptors.

Alkaloids↗

PubMed1992

Electroacupuncture enhances activity of adrenal nucleolar organizer regions in ovariectomized rats.

Nucleolar organizer regions (NORs) may reflect the activity of cell differentiation and transcription of nucleolar rDNA; the present paper studied nucleolar organizer regions of the adrenal cortex to explore the regulatory effect of electroacupuncture (EA). Animals were divided into four groups, the ovariectomized electroacupuncture group (OV+EA group, n = 7), the ovariectomized group (OV group, n = 4), the EA group (n = 3) and the control group (CT group, n = 4). Number of AgNORs of 100 cells from zona fasciculata of the adrenal cortex in each case of the four 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, 1.26 +/- 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 less than 0.01) as tested with ANOVA and LSD method. No significant difference was found among the other three groups. Gross specimen examination showed that adrenals in the OV+EA group were significantly heavier than those in the other three groups (p less than 0.01). Vaginal smears showed that a response like estrogen-induced one with exfoliative cells appeared in the OV+EA group. EA had no significant effect on normal rats. The results suggest that EA may promote the synthesis and secretion of adrenal steriod 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↗

PubMed1991

Acyclonucleoside analogue inhibitors of mammalian purine nucleoside phosphorylase.

A series of about 60 purine acyclonucleosides, most with guanine as the aglycone and a 4-carbon chain as the acyclic moiety, was examined for ability to inhibit purine nucleoside phosphorylase from human erythrocytes and calf spleen. Compounds with shorter and longer acyclic chains were less effective inhibitors. Synthetic procedures are described. About 25 of the analogues were competitive inhibitors (relative to inosine or 7-methylguanosine as substrates) with Ki values in the range of 2 to 100 microM. The more potent ones (Ki 2-5 microM) included guanine as the aglycone, with various substituents at C(2') of the acyclic chain and hydroxyls at C(3') and C(4'). In one instance, 9-(2-fluoro-3,4-dihydroxybutyl)guanine, the (+)erythro enantiomer was 10-fold more effective than its (-) counterpart (2.5 microM vs 27 microM). Replacement of guanine by 8-bromo- or 8-aminoguanine enhanced affinity for the enzyme by an order of magnitude or more; 7-deazaacyclovir was also 10-fold more effective than acyclovir. With some of the inhibitors, Ki (human)/Ki (calf) varied over the range 0.4 to 4, reflecting differences between the two enzymes; nonetheless, the much more stable, and commercially available, calf spleen enzyme is recommended for preliminary screening of potential inhibitors of the human or other unstable enzymes. The overall results provide useful indications for the synthesis of potentially more potent inhibitors of the enzyme, by simultaneous modifications of the aglycone and the acyclic chains.

Acyclovir↗

PubMed1991

Relationship between blood radioimmunoreactive beta-endorphin and hand skin temperature during the electro-acupuncture induction of ovulation.

Thirteen cycles of anovulation menstruation in 11 cases were treated with Electro-Acupuncture (EA) ovulation induction. In 6 of these cycles which showed ovulation, the hand skin temperature (HST) of these patients was increased after EA treatment. In the other 7 cycles ovulation was not induced. There were no regular changes in HST of 5 normal subjects. The level of radioimmunoreactive beta-endorphin (r beta-E) fluctuated, and returned to the preacupunctural level in 30 min. after withdrawal of needles in normal subjects. After EA, the level of blood r beta-E in cycles with ovulation declined or maintained the range of normal subjects. But the level of blood r beta-E in cycles in which the induction failed to cause ovulation was kept higher that that of normal. (P less than 0.05). There was a negative correlation in the decrease of blood r beta-E and increase of HST after EA (r = 0.677, P less than 0.01). EA is able to regulate the function of the hypothalamic-pituitary-ovarian axis. Since a good response is usually accompanied with the increase of HST, monitoring HST may provide a rough but simple method for predicting the curative effect of EA. The role of r beta-E in the mechanism of EA ovulation induction was discussed.

Anovulation↗

PubMed1989

Change of Leu-enkephalin- and B-endorphin-like immunoreactivity in the hippocampus after electroconvulsive shock and electroacupuncture.

To determine whether the effect of electroacupuncture (EA) on electroconvulsive shock (ECS) was through affecting endogenous opioid peptidergic system in the hippocampus, we used radioimmunoassay (RIA) to measure leu-enkephalin- and beta-endorphin-like immunoreactivity (L-E-LI and Beta-E-LI) in the hippocampal perfusate after ECS and EA treatments. Wistar rats were given ECS stimulation, which caused behavioral and electroencephalogram (EEG) convulsions. However, EA could suppress ECS-elicited convulsions (including both behavioral and EEG abnormalities). The results of RIA showed that after repeated ECS treatments, the contents of L-E-LI and Beta-E-LI increased significantly by 136% and 157%, respectively. In contrast, EA treatment depleted alterations of L-E-LI and Beta-E-LI induced by ECS, depleting L-E-LI by 32% and Beta-E-LI by 85%. These observations suggest that anticonvulsive action of EA is related to the release of L-E and Beta-E in hippocampus, probably through decreasing their release, thus to exert EA action.

Animals↗

PubMed1988

Phagocytic labeling of leukocytes with 99mTc-albumin colloid for nuclear imaging.

A procedure is described for the phagocytic labeling of white blood cells (WBC) with high specific activity 99mTc--albumin colloid (TAC). The preparation contains approximately equal activities of granulocytes and monocytes. Heparinized whole blood (40 cm3) yields a preparation containing a total of 148-222 MBq (4-6 mCi) TAC-WBC including about 20% free TAC. The complete preparation time is 75 min. Imaging is completed 30 min to 4 h post administration of the TAC-WBC. Quality control methods and imaging protocols are described.

Adult↗

PubMed1987