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Biomedical subjects

J M Zhang

Publications and source records attributed to J M Zhang.

At least 55 records · Page 3Linked to original sources
PubMed1993

[A chiral capillary gas chromatographic method for direct determination of enantiomers of mephenytoin in human urine].

A gas chromatographic method equipped with nitrogen-phosphorus detector was developed for the determination of the S- and R-enantiomers of the anticonvulsant, mephenytoin (MP) in human urine. Dichloromethane (4 ml) was added to 1 ml urine, the mixture was shaken and centrifuged. The organic phase was transferred to another tube and blown to dryness under nitrogen on water bath (37 degrees C). The residue was dissolved in 10 microliters ethylacetate and 1-2 microliters was injected into the GC. Our results showed that direct enantiomeric separation of mephenytoin was obtained by using a chiral capillary column, the retention times for S- and R-mephenytoin were 25.5 and 26.2 min respectively, with a detection limit less than 50 ng/ml of mephenytoin. Similar linear and reproducible standard curves were obtained over the concentration range of 53.2 to 2128.0 ng/ml (for S-MP, r = 0.9914 +/- 0.0070, n = 6; and for R-MP, r = 0.9939 +/- 0.0070, n = 6), and the mean recoveries of S- and R-MP were 95.4% and 95.8% respectively. The within-day relative standard deviations were less than 8.8% for both S- and R-MP, and that of between-days were less than 14.3%. There was a good reproducibility of the urine S/R mephenytoin determined in China and in Sweden by using similar method in 107 Chinese volunteers after a single oral dose of 100 mg racemic mephenytoin (r = 0.9091, P < 0.001).

Chromatography, Gas↗
PubMed1993

[Efficacy of xiaoxingzhang guttae ophthalmic eye drops in the treatment of experimental herpes simplex keratitis].

The new guttae ophthalmic Xiaoxingzhang (XXZ) was extracted from Radix Actinidiae, a traditional Chinese herbal drug. The 50% inhibition concentration (IC50) of XXZ on type I Herpes Simplex Virus (HSV-1) in virus cell cultures is 165.48-174.73 micrograms/ml. However, XXZ concentrations greater than 400 micrograms/ml did not cause any microscopically visible disruption of vero cells. The efficacy of XXZ in the treatment of experimental Herpes Simplex Keratitis (HSK) in rabbits is higher than that of idoxuridine. The effective doses of XXZ are not toxic to corneal epithelium. The results suggest that XXZ as a new anti-HSV preparation is potentialy useful in the treatment of patients with HSK.

Adjuvants, Immunologic↗
PubMed1992

Characterization of the norepinephrine uptake system and the role of norepinephrine in the expression of the adrenergic phenotype by quail neural crest cells in clonal culture.

This study investigates the role norepinephrine (NE) may play in regulating the differentiation of quail neural crest cells into sympatho-adrenal cells. Cues originating from the embryonic microenvironment are thought to play an important role during development. It is conceivable that NE has a positive regulatory function because adrenergic expression by quail neural crest cells in clonal culture can be inhibited by NE uptake inhibitors such as desipramine (DMI). This possibility is further supported by the notion that in the avian embryo presumptive adrenergic neural crest cells are likely to encounter catecholamines shortly after they have acquired the NE uptake mechanism. Our present data indicate that neural crest cells in clonal culture express a high affinity NE uptake system that can be inhibited by desipramine. As in the embryo, it appears before noticeable levels of catecholamines are accumulated by neural crest cells, as judged by formaldehyde-induced catecholamine fluorescence (FIF). A comparison of the time course of appearance of different adrenergic markers suggests that immunoreactivity against the biosynthetic enzyme tyrosine hydroxylase (TH) may appear first, and that it is followed very closely by the appearance of detectable levels of dopamine-beta-hydroxylase (DBH) and the NE uptake mechanism. Accumulation of catecholamines (FIF) is observed last. Addition of exogenous NE leads to an increase in adrenergic expression in vitro as judged by an increase in the number of colonies containing FIF-positive cells as well as cells expressing the biosynthetic enzymes TH and DBH. This suggests that exogenous NE can play a positive regulatory role in the differentiation of quail neural crest cells into sympathoadrenal cells.

Animals↗
PubMed1991

Lipoprotein receptor activity of peritoneal macrophages from insulin-deficient mice.

Binding, uptake and degradation of 125I-labeled normal very low density lipoprotein (125I-n-VLDL) from normal swine plasma and 125I-labeled beta-migrating VLDL (125I-beta-VLDL) from hypercholesterolemic rabbit plasma by peritoneal macrophages of mice rendered insulin-deficient by streptozotocin (250 mg/kg) were studied. It was found that the amount of binding, uptake and degradation of 125I-n-VLDL by macrophages from the diabetic mice was 2-fold or 2.5-fold higher than by macrophages from normal mice, resulting from an increase in the binding capacity of VLDL receptors on the macrophages from the insulin-deficient rodents. In contrast, the binding, uptake and degradation of 125I-beta-VLDL by macrophages from diabetic mice were reduced to only about 45% of normal levels because of a decrease in the number and affinity of the receptors for beta-VLDL. These experimental results indicate that n-VLDL is more important than beta-VLDL in the pathogenesis of atherosclerosis in insulin-dependent diabetes.

Animals↗
PubMed1990

[Study of characteristics of monoclonal antibody against substance P].

Cross-reaction of a rat monoclonal antibody (BTP-1) against seventeen substance P analogues was studied. The antibody was of IgG type and related to the carboxyl terminal of substance P, especially methionyl in the terminal, but did not depend on the strength of antagonistic effects of these analogues. It did not show cross-reaction with the following nine peptides: glucagon, endorphin, angiotensin I, II, leucine-enkephalin, methionine-enkephalin, bradykinin, oxytocin and dernorthin, indicating its high specificity to substance P. By means of immuno-enzyme histochemical method, it was shown that stained nerve fibers were located in the gelaliternous substance of Rolando, interpeduncular nucleus, substantia nigra and nerve cell bodies in the vestibular nucleus, lateral tegmental nucleus of mesencephalon and ventral region of third ventricle.

Animals↗
PubMed1989

[The effect of electro-acupuncture of "neiguan" acupoint on cortical potential evoked by stimulating C-fibers of splanchnic nerve].

In this paper the averaged cortical evoked potential (C-CEP) induced by stimulating the C-fibers of the splanchnic nerve was used as an index of visceral pain to further study the effects of acupuncture and morphine on it. Experiments were carried out on 35 cats anesthetized with chloralose and immobilized with flaxedil. The splanchnic nerve was stimulated with electric pulses of varied strength and blocked by a galvanic current so as to cause A- or C-fibers input selectively. The cortical evoked potential was recorded on the contralateral post-sigmoid gyrus and averaged by TQ-19 Medical Data Processor. The compound action potential of splanchnic nerve was monitored. "Neiguan" acupoint was stimulated with electric pulses (0.1ms, 4v and 5Hz). The results were as follows: 1) when "Neiguan" acupoint, was excited with the electric pulses, C-CEP and the late component of A-CEP which was evoked by stimulating A-fibers of splanchnic nerve were obviously reduced in amplitudes. It was suggested that electro-acupuncture (EA) of "Neiguan" acupoint could inhibit visceral pain (the slow and fast pain). 2. After intravenous injection of morphine, the amplitudes of C-CEP and the late component of A-CEP were depressed significantly, indicating that C-CEP might reflect the visceral slow pain and the late component of A-CEP reflect the fast pain. 3. Naloxone could block partially the inhibitory effect of EA of "Neiguan" acupoint on C-CEP, suggesting that the inhibition of EA might be associated with the release of endogenous opiate like substances.

Acupuncture Points↗
PubMed1989

[The effect of electrical stimulation of the head of caudate nociceptive neuronal activities in the mesencephalon reticular formation and its relation to the acupuncture effect].

38 rabbits were anesthetized with chloralose and urethane. As soon as the animal recovered its consciousness it was immobilized with flaxedil and artificial respiration. The electrical activities of the nociceptive neurons were recorded by glass microelectrodes (tip 1-3 microns) in the ranges P7-11 R2-3 HO+1-6, with the aid of a stereotaxic apparatus. 116 of the nociceptive units responded to noxious stimuli which applied to the peroneal nerve with a short train of pulses. Among them, 64 units (55%) responded by an increase in frequency of the discharge to noxious stimuli (pain-excitation neuron, PEN). In contrast, there were 52 units (45%), which responded to noxious stimuli quite differently, by having a decrease in the frequency of the discharge (pain-inhibition neuron, PIN). Similar results were obtained by the stimulation of the head of caudate nucleus with the same train of pulses: an excitatory effect was observed in PEN, and an inhibitory effect in PIN. However, after electroacupuncture by penetrating acupoint "Hegu" or dolantin given intravenously, under the same conditions used above. We again stimulated both the head of caudate nucleus, eliciting an inhibitory effect on PEN. And a reduction of inhibition or release from it on PIN. From the results presented, it indicated that head of caudate nucleus was connected with the modulation of the nociceptive neuronal activity in M.R.F. and was related to the effect of acupuncture. The effect of atropine on the head of caudate nucleus stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Minimal deviation endocervical adenocarcinoma--clinical, histologic and immunohistochemical study].

Minimal deviation endocervical adenocarcinoma (MDA) is a rare form of adenocarcinoma which differentiates well, grows rapidly, spreads early and has poor prognosis. In this series, 9 cases of MDA and its clinical, histologic and immunohistochemical characteristics are reported. The main clinical pictures were enlarged cervix with marked increase in vaginal discharge (7 cases) and irregular vaginal bleeding (2 cases). Histologically, this neoplasm was composed of structures almost identical to normal endocervical glandular patterns characterized by a haphazard proliferation of both large claw-shaped glands and small, slit-shaped, pointed glands which penetrated into the wall of the cervix beyond 5 mm in depth. Focal mild cytologic atypia was demonstrated in each case. Immunohistochemical stains showed focal cytoplasmic carcinoembryonic antigen (CEA) in each neoplasm. Seven of the nine patients were followed: four died of their neoplasms, one survived for more than 2 years, one for 1 year, and one was a new case. The diagnostic features and characteristics of immunohistochemistry of this cancer are described and its nomenclature, clinical manifestations and prognosis and discussed.

Adenocarcinoma↗
PubMed1989

[18 cases of sarcoidosis and a review of relevant literature].

In this article 18 cases of sarcoidosis are reported. Among these, 14 were diagnosed pathologically and 4 were diagnosed clinically. Sarcoidosis in both mother and daughter is reported for the first time. There were central lobe lesion in 3 cases, pleural lesion in 4 cases, and idiopathic pneumothorax during treatment of early lesion in 1 case. A discussion is made with reference to relevant literature.

Adult↗
PubMed1987

Purification and characterization of serotype 6 fimbriae from Bordetella pertussis and comparison of their properties with serotype 2 fimbriae.

Fimbriae were removed from Bordetella pertussis (serotype 1.3.6) by mechanical shearing and purified by precipitation with ammonium sulfate, pH-dependent precipitation at pH 7.4, followed by two successive extractions of the precipitated fimbriae with 4 M urea. By electron microscopy, the precipitated fimbriae appeared as aggregated bundles of long, relatively straight filaments which were disaggregated to individual flexuous filaments at pH 10.5. These purified fimbriae were identified as serotype 6 agglutinogens, since antibody to the purified fimbriae agglutinated B. pertussis strains serotyped as 1.3.6, 1.2.3.6, or 1.2.3.4.6 but did not agglutinate strains of serotype 1.2.3.4, 1.2.3, or 1.3. In contrast, antibody to serotype 2 fimbriae only agglutinated B. pertussis strains containing serotype 2 agglutinogen. Purified type 6 and 2 fimbriae were found to be weakly cross-reactive by enzyme-linked immunosorbent assay, using polyclonal antibody to each type of fimbria. In an immunoblot assay, polyclonal antibodies to a 22,000-dalton subunit of fimbriae from B. bronchiseptica reacted strongly with the type 2 fimbrial subunit of B. pertussis, but only weakly with the type 6 subunit. When subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protein subunit of the type 6 fimbriae migrated with a molecular weight of 21,500, whereas the type 2 fimbrial subunit had a molecular weight of 22,000. The two types of subunits had similar amino acid compositions and showed amino-terminal sequence homology in 15 of 21 amino acids. The amino-terminal amino acid sequences of the B. pertussis fimbriae were distinct from those reported for fimbriae from other gram-negative bacteria. Neither the type 6 nor the type 2 fimbriae caused hemagglutination when assayed with several types of erythrocytes.

Amino Acid Sequence↗