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J Fang

Publications and source records attributed to J Fang.

At least 325 records · Page 18Linked to original sources
PubMed1993

High-performance liquid chromatographic method for the detection and quantitation of haloperidol and seven of its metabolites in microsomal preparations.

An isocratic high-performance liquid chromatographic (HPLC) system was developed to analyze haloperidol and its potential metabolites. These compounds included 4-(4-chlorophenyl)-4-hydroxypiperidine (CPHP), haloperidol N-oxide (HNO), reduced haloperidol (RHAL), the 1,2,3,6-tetrahydropyridine analogue and its N-oxide, and the pyridinium ion from haloperidol (HP+). The HPLC system comprised a Hypersil CPS5 column with a mobile phase of acetonitrile (67%) and ammonium acetate (final concentration 10 mM) which was adjusted to pH 5.4 by acetic acid. The solvent was delivered at 1 ml/min. RHAL and CPHP were determined by an ultraviolet detector at 220 nm with a detection limit of 1 nmol/ml. All other compounds were determined at 245 nm and had a detection limit of 0.3 nmol/ml. This system was used to analyze a microsomal metabolic mixture of haloperidol. It was found that all above compounds except HNO were metabolites of haloperidol. In addition, two other metabolites were also well separated in this HPLC system which are proposed to be oxygenated haloperidol and the pyridone analogue of haloperidol. The HPLC system was used to carry out quantitative metabolic studies of haloperidol. It was found that the metabolism of haloperidol exhibits large inter-species differences. The apparent enzyme kinetic parameters were also determined using mice microsomes.

Animals↗
PubMed1993

Effects of pretreatment with androgen or thyroid hormone on androgen-induced proliferation of granular convoluted tubular cells in mouse submandibular glands.

The effects of pretreatment with androgen or thyroid hormone on androgen-induced proliferation of granular convoluted tubular cells (GCT cells) in the submandibular glands of ovariectomized female BALB/c or C57BL/6 mice were investigated. The proliferation of GCT cells was estimated by their labeling index. Daily injections of 5 alpha-dihydrotestosterone (DHT) (100 micrograms/mouse/day) caused a transient increase in the labeling index of GCT cells of ovariectomized 60-day-old BALB/c mice during the first four injections, but injections of thyroxine (T4) (15 micrograms/mouse/day) did not. On the other hand, both DHT and T4 increased the esteroprotease activity, a marker of the differentiation of GCT cells, time dependently. Injections of DHT into ovariectomized 102-day-old BALB/c mice also caused a transient increase in the labeling index of GCT cells. However, pretreatment of ovariectomized 60-day-old BALB/c mice with DHT for 4 or 14 days completely abolished the DHT-induced increase in the labeling index of 102-day-old mice, and pretreatment with T4 for 14 days reduced this increase. Pretreatment with DHT or T4 for 14 days did not affect the DHT-induced increase in esteroprotease activity. Pretreatment of ovariectomized 60-day-old C57BL/6 mice with DHT for 14 days also completely abolished the DHT-induced increase in the labeling index of GCT cells at the age of 102 days, but pretreatment with T4 for 14 days did not affect the increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Variability of motor potentials evoked by transcranial magnetic stimulation.

We studied the effect of stimulus intensity, coil size, mental alertness and prestimulus muscle contraction on the variability of motor evoked potentials (MEPs) produced by magnetic cortical stimulation (MCS). In 5 healthy subjects we delivered MCS either with a circular coil centered at the vertex or a figure-8 coil centered over the motor cortex hand area, recording from first dorsal interosseous. With the subject at rest or exerting 5% maximum voluntary contraction, 30 consecutive stimuli were given at 4 stimulus intensities (SIs) in 10% increments above resting motor threshold. Concurrent mental arithmetic constituted mental alertness. Spectral analysis was performed on data from 300 consecutive stimuli. The variability of MEP response size was inversely related to stimulus intensity, prestimulus voluntary muscle contraction, the recruitment of motoneurons and the size of the field generated by the magnetic coil. The MEP variability was larger than and not correlated with the variability of the H-reflex. Fast Fourier transformation and cross-correlation analysis did not identify a consistent dominant frequency, suggesting that the variability in MEP size is essentially random. We suggest that the variability in MEP response is caused by constant, rapid, spontaneous fluctuations in corticospinal and segmental motoneuron excitability levels. Any maneuver that raises this level or increases the probability of motoneuron firing will decrease MEP variability.

Adult↗
PubMed1993

Facilitation of magnetic motor evoked potentials during the cortical stimulation silent period.

We investigated the relationship between stimulus intensity and magnetic motor evoked potentials (MEPs) elicited 100 msec after a conditioning stimulus that was 25% of stimulator output above resting motor threshold (RMT) during tonic contraction of abductor pollicis brevis. In five subjects, MEPs elicited with stimuli less than 25% above RMT were inhibited during the EMG cortical stimulation silent period (CSSP) produced by the conditioning stimulus, relative to MEPs elicited with the test stimulus given at rest. However, increasing the intensity of the test stimulus increased the amplitude of MEPs elicited during the CSSP relative to MEPs elicited at rest, such that MEPs elicited with stimuli 30 to 45% above RMT were facilitated during the CSSP. Increasing the intensity of the test stimulus also increased the amplitude of MEPs elicited with paired stimulation at rest, and caused facilitation in one subject. Since facilitation of MEPs was never accompanied by shortening of MEP latency, our observations point to supraspinal facilitory mechanisms. We suggest that facilitation of MEPs during the CSSP reflects temporal and spatial summation of conditioning and test stimuli.

Adult↗
PubMed1993

On the metabolism of haloperidol.

1. p-Fluorobenzoyl-propionic acid, 4-(4-chlorophenyl)-4-hydroxy-piperidine, and reduced haloperidol were confirmed as metabolites of haloperidol. Their formation was catalysed by hepatic microsomes and was NADPH dependent. 2. The pyridinium metabolite of haloperidol (HP+) was identified. It is proposed that haloperidol first undergoes dehydration to form its 1,2,3,6-tetrahydropyridine analogue (HTP). HTP is then further metabolized to HP+, HTP N-oxide and its N-dealkylated product, 4-chlorophenyl-1,2,3,6-tetrahydropyridine (CPTP). HTPN-oxide was metabolized to CPTP and HTP. All these metabolites were confirmed by comparison with synthesized compounds using h.p.l.c. and h.p.l.c.-mass spectrometry. 3. Three unknown metabolites were present in microsomal metabolic incubations of haloperidol. One of them was tentatively characterized by h.p.l.c.-mass spectrometry as an oxygenated product of haloperidol, another appears to be the 2-pyridine analogue of haloperidol. The third metabolite was shown to be a neutral compound of unknown structure, which was not haloperidol N-oxide nor 4-hydroxy-4'-fluorobutyrophenone. In addition, HTP was metabolized to a further unknown product with a similar u.v. spectrum to that of HTP. 4. The identification of these metabolites led to the hypothesis that the metabolism of haloperidol is similar to that of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and may therefore produce motor neurone toxicity by a similar mechanism.

Animals↗
PubMed1993

Effect of platelet activating factor antagonist WEB 2086 on the production of TNF from murine peritoneal macrophages.

In the present study the effect of platelet activating factor (PAF) antagonist WEB 2086 on the production of tumor necrosis factor (TNF) from primed murine peritoneal macrophages was investigated. At 10(-6) and 10(-5) mol/L, WEB 2086 was found to significantly inhibit LPS induced TNF production from macrophages by activated thioglycollate solution. WEB 2086 inhibition of TNF release began 4 h after LPS stimulation and lasted 22 h with a peek at 16 h. The results showed that PAF might play an important role in the production of TNF. Four methods were compared in the bioassay of TNF. The data demonstrated that L-929 cells treated with actinomycin D and sodium fluoride were the most sensitive for the assay of TNF. This method was employed in this study.

Animals↗
PubMed1993

[Effects of Phytolacca acinosa polysaccharide on splenic lymphocyte proliferation and cytokine secretion from splenic lymphocyte and macrophage].

The effects of Phytolacca acinosa polysaccharides I (PAP-I), a polysaccharide extracted from Phytolacca acinosa Roxb: on splenic lymphocyte proliferation and cytokines production from splenic lymphocyte and macrophage were studied. Lipopolysaccharides (LPS) and PAP-I were found to significantly augment splenic lymphocyte proliferation of normal BALB/c, nude BALB/c and NC mice in vitro, but concanavalin A (Con A) was shown to stimulate only normal BALB/c and nude BALB/c splenic lymphocyte proliferation. Also, PAP-I significantly enhanced Con A or LPS-induced lymphocyte proliferation and mixed lymphocyte reaction. Significant enhancement of colony stimulating factor (CSF) production was observed from splenic lymphocyte of normal BALB/c and nude BALB/c mice but not from NC mice when treated with PAP-I for 5 d. PAP-I was shown to significantly enhance interleukin-2 (IL-2) production from normal mice splenocyte and Con A stimulated normal mice splenocyte in a concentration-dependent fashion. Supernatant of PAP-treated macrophage (M phi) were collected and CSF activity was tested. The results confirmed that PAP-I can significantly stimulate M phi to secret CSF activity on d 1. The supernatant also contained a cytokine which exhibited a synergistic action with recombinant murine granular-macrophage CSF (RMGM-CSF) to stimulate mice bone marrow cell proliferation. PAP-I, 5-50 mg.kg-1, ip can enhanced splenic lymphocyte proliferation and IL-2 production. These findings indicate that PAP-I can augment immunologic function in vitro and in vivo.

Animals↗
PubMed1993

High level expression of human prourokinase cDNA in Chinese hamster ovary cells.

We have used Chinese hamster ovary (CHO) cells to express high levels of human prourokinase gene cDNA with recourse to construction of good expression vector, the improvement of transfection technique and gene coamplification. First, we constructed expression plasmid pMG10102 by placing pro-UK cDNA under the control of SR alpha promoter/SV40 polyadenylation signals and expressed it transiently in COS-7 cells. Expression level was about 5 times higher than with SV40 early promoter. Linear plasmids pMG10102 and pSV2-dhfr were then cotransfected into CHO-dhfr cells by calcium phosphorate coprecipitation and cells were cultured in selective medium. Twenty transformants expressing pro-UK were picked, the range of expression levels was 12.5-100IU/10(6) cells/day. When subjected to stepwise selection of methotrexate (MTX), the stable cell lines were obtained that secreted up to 400-500IU/10(6) cells/day. Western blot analysis showed that molecular weight of secreted recombinant pro-UK was the same as that of natural pro-UK, which is 52 kDa, and more than 60% of expression production was single chain urokinase (rscUK) without protease inhibitor in medium.

Animals↗
PubMed1993

Cloning of human prourokinase cDNA without the signal peptide and expression in Escherichia coli.

Human prourokinase (pro-UK) cDNA without the signal peptide was obtained using synthetic oligonucleotide and DNA recombination techniques and was successfully expressed in E. coli. The plasmid pMMUK which contained pro-UK cDNA (including both the entire coding sequence and the sequence for signal peptide) was digested with Hind III and PstI, so that the N-terminal 371-bp fragment could be recovered. A 304-bp fragment was collected from the 371-bp fragment after partial digestion with Fnu4HI in order to remove the signal peptide sequence. An intermediate plasmid was formed after this 304-bp fragment and the synthetic oligonucleotide was ligated with pUC18. Correctness of the ligation was confirmed by enzyme digestion and sequencing. By joining the PstI-PstI fragment of pro-UK to the plasmid we obtained the final plasmid which contained the entire coding sequence of pro-UK without the signal peptide. The coding sequence with correct orientation was inserted into pBV220 under the control of the temperature-induced promoter PRPL, and mature pro-UK was expressed in E. coli at 42 degrees C. Both sonicated supernatant and inclusion bodies of the bacterial host JM101 showed positive results by ELISA and FAPA assays. After renaturation, the biological activity of the expressed product was increased from 500-1000IU/L to about 60,000IU/L. The bacterial pro-UK showed a molecular weight of about 47,000 daltons by Western blot analysis. It can be completely inhibited by UK antiserum but not by t-PA antiserum nor by normal rabbit serum.

Base Sequence↗
PubMed1993

Effects of Phytolacca acinosa polysaccharides I on immune function in mice.

Radioactivities of [3H]TdR uptaken by splenocytes and released from [3H]TdR-labeled YAC-1 cell line were measured to determine the degree of lymphocyte proliferation and natural killer (NK) cell activity. Seven days after mice treated with Phytolacca acinosa polysaccharides I (PAP-I) 5-50 mg.kg-1, the NK cell activity, and lymphocyte proliferation induced by Con A 5 micrograms.ml-1 or lipopolysaccharides 10 micrograms.ml-1 were significantly augmented. Splenocytes from mice treated with ip PAP-I 5-50 mg.kg-1 were incubated with Con A 5 micrograms.ml-1 for 24 h to induce interleukin-2 (IL-2) and for 40 h to induce NK cytotoxic factor (NKCF). Radioactivities of [3H]TdR uptaken by CTLL-2 cell line and YAC-1 cell line were used to measure the IL-2 and NKCF activities, respectively. PAP-I enhanced the production of IL-2 and NKCF. These results suggest that PAP-I augments the immunological functions in vivo.

Adjuvants, Immunologic↗
PubMed1993

[Effects of Phytolacca acinosa polysaccharides II on lymphocyte proliferation and colony stimulating factor production from mice splenocytes in vitro].

Phytolacca acinosa polysaccharides II (PAP-II), a kind of polysaccharides isolated from Phytolacca acinosa Roxb with MW 40 kDa, on lymphocyte proliferation and colony stimulating factor (CSF) production from splenocytes in vitro, was studied. The radioactivities of [3H] TdR uptake by lymphocyte and bone marrow cells were used to determine the ability of lymphocyte proliferation and CSF production respectively. PAP-II was found to significantly augment splenocyte proliferation in a dose-dependent fashion, and significantly enhance Con A (1, 2.8 micrograms.ml-1) and LPS (3, 10, 30 micrograms.ml-1) induced lymphocyte proliferation at concentration of 31-125 micrograms.ml-1. As the concentration of PAP-II increased, significant suppression of Con A-induced lymphocyte proliferation was observed. Induction of CSF by PAP-II from splenocyte was confirmed at the present study. The optimal dosage was 100 micrograms.ml-1 and the optimal effect occurred on day 5. These results suggest that PAP-II can augment immunological function and enhance hematopoiesis.

Animals↗
PubMed1992

Comparison of electric and magnetic coil stimulation in the supraclavicular region.

We compared the compound motor action potentials (CMAPs) evoked in the biceps, triceps, and abductor digiti minimi (ADM) muscles by conventional electrical stimulation at Erb's point (EP), and by magnetic coil stimulation of the supraclavicular region in 11 normal subjects. We found that magnetic coil stimulation was less effective than conventional stimulation in activating motor fibers in the brachial plexus in 45% of the recordings analyzed. CMAP amplitudes greater than those obtained with EP electrical stimulation were seen in 16% of recordings with supraclavicular magnetic stimulation, and in 33% of recordings with cervical magnetic stimulation, indicating that EP electrical stimulation is submaximal in a large proportion of cases.

Action Potentials↗
PubMed1992

Cryopreservation of embryonic cerebral tissue of rat.

Embryonic cerebral tissues (ECT) either fresh or frozen-stored, were cultured and transplanted into the cerebella of neonatal host rats. Many variables including composition of the freezing medium, freezing and thawing rates, and storage time in liquid nitrogen were studied systematically. The results indicated that the following conditions yielded good results for tissue culture: using 1 M Me2SO as the cryoprotectant, freezing the brain tissues at a rate of 1 degrees C/min until it reached -70 degrees C, storing the frozen samples in liquid nitrogen and thawing them fast in a 37 degrees C water bath. The viability of the frozen-thawed tissues was assessed by their abilities to grow and differentiate in vitro and in vivo after intracerebral grafting. In tissue culture, growth and differentiation were similar to those of the fresh ECT. Cell morphology and staining reactions were normal in supravital methylene blue staining, cresyl violet staining, and acetylcholinesterase staining. Neurons had well-developed Nissl bodies, and cholinergic neurons also differentiated. Autoradiographic studies showed that more than 50% of the neurons had the ability to uptake gamma-aminobutyric acid with high affinity. In brain tissue transplantation, 9 of 12 transplants survived subsequent grafting after cryopreservation. Moreover, the grafts of surviving cryopreserved tissue displayed cytological and cytoarchitectural characteristics identical to those of fresh grafts. All grafts were integrated with the surrounding host neural tissue. This suggested that there may be synaptic connections between the transplants and the host brain tissues. From this and similar studies on the subject by others wer conclude that cryopreservation is a feasible method for storage of embryonic brain tissue to be used later for intracerebral grafting.

Animals↗
PubMed1992

Descending pain inhibitory system involved in acupuncture analgesia.

The descending pain inhibitory system (DPIS) associated with acupuncture analgesia (AA), caused by low frequency stimulation of an acupuncture point, was identified by the results of lesion and stimulation procedures previously determined to differentiate the afferent and efferent paths in rats. The DPIS starts in the posterior arcuate nucleus and descends to the hypothalamic ventromedian nucleus (HVM) from whence it divides into two pathways: one path, the serotonin mediated path, descends through the ventral periaqueductal central gray (V-PAG) and then to the raphe magnus (RM). The other, the noradrenaline mediated path, descends through the reticuloparagigantocellular nucleus (NRPG) and part of the reticulogigantocellular nucleus (NRGC). The afferent and efferent paths are both present in the RM and NRGC, and were separately identified by means of the analgesia (SPA) produced by stimulation of the separate regions in AA responders and nonresponders, because SPA of these regions in nonresponders produced only efferent pathway mediated analgesia.

Acupuncture Analgesia↗
PubMed1992

[Cost-effectiveness analysis of short-term course and regular course of antithyroid drug therapy for Graves' disease].

One hundred and- eighteen newly diagnosed patients with Graves' disease were treated by tapazole for 6 months (short-term course) and followed up for another 12 months. Forty three percent remission rate was found in this group. A regular course of antithyroid drug therapy for 1.5-2 years with 50% remission rate was taken as control. Cost-effectiveness analysis was made to compare the cost in the two different kinds of therapy. The results showed that the total costs of the treatment per 100 cases were 17,746 yuan for the short-term therapy and 30,708 yuan for the regular therapy, with an average of 412.7 yuan and 614.2 yuan per case respectively. In comparison with the short-term therapy, the regular course could remit 7 more cases at a cost of 12,962.40 yuan, with an average of 1851.80 yuan per case. Therefore, the cost was high by prolonged course of therapy to increase slightly remission rate, although it could remit a few more cases. This study suggests that six-month treatment is preferable for those who live in the rural or remote area where the economy was less developed. A longer course of therapy may be unnecessary for those who have been treated by antithyroid drugs for 6 months or longer and are predicted to obtain a possible prolonged remission.

Cost-Benefit Analysis↗
PubMed1991

Dehydration is the first step in the bioactivation of haloperidol to its pyridinium metabolite.

Haloperidol was found to have a similar metabolic pathway to that of the neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice microsomal preparations. The 1,2,3,6-tetrahydropyridine derivative of haloperidol was detected in NADPH-fortified metabolic incubation mixtures of haloperidol. Incubation of this dehydrated haloperidol produced the pyridinium metabolite. These metabolites were confirmed by comparison with synthesised compounds using HPLC and HPLC-MS. Dehydration of an alcohol to a double bond represents a novel metabolic pathway. This novel metabolic pathway indicates a MPTP-like mechanism for the Parkinsonism observed with haloperidol in clinical use.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1991

[Inhibitory effect of esculentoside A on platelet activating factor released from calcimycin induced rat peritoneal macrophages].

Platelet activating factor (PAF) is a kind of inflammatory mediator. We used the method of aggregation of washed rabbit platelet to study the effect of esculentoside A (EsA) on the release of PAF from calcimycin (A23187)stimulated rat peritoneal macrophages and found that the release of PAF was inhibited by EsA in a time and dose dependent manner. The IC50 of EsA for the inhibition of PAF release was 1.5 mumol/L. Under the same condition, the release of PAF was also inhibited by mepacrine at 100 mumol/L. The results indicate that EsA is a potent inhibitor of PAF synthesis in rat peritoneal macrophages.

Animals↗