Biomedical subjects
Publications and source records attributed to L Z Zhang.
In the title compound, [Cu(C(15)H(22)NO)(2)], the Cu(II) cation lies on a centre of symmetry. The coordination geometry about the Cu(II) ion is a parallelogram, formed by the N(2)O(2) donor set of the two bidentate long alkane chain Schiff base imine-phenol ligands. The Cu-N and Cu-O distances are 2.009 (3) and 1.888 (3) A, respectively.
Counter-current chromatography is a real liquid-liquid chromatography. The retention volume of the solute can be calculated from the batch distribution ratio in organic separations. In the separations of metal ion, there are several complex and dissociation reactions involved in the two phases, and the retention volume cannot be always predicted from the batch distribution ratio. A mass transfer model is proposed in this paper and an expression of V(R) is derived. The retention volume of metal ion is determined not only by the batch distribution ratio but also by the mechanism of the extraction reaction. When 25% dihexyl-N,N-diethylcarbamoyl methylenephosphonate in cyclohexane is used as stationary phase and 2.91 mol/l HNO3 as mobile phase, the dynamic distribution ratios obtained from the chromatogram are not equal to but proportional to the batch distribution coefficients. These results are in agreement with the theoretical expression.
OBJECTIVE: To investigate the chemical constituents of Phyllanthus urinaria. METHOD: Various chromatographic techniques were employed for isolation and purification of the constituents. The structures were elucidated by chemical and spectral analyses. RESULT AND CONCLUSION: Fourteen compounds were isolated and seven of them were identified as corilagin(I), rutin(II), brevifolincarboxylic acid(VI), isostrictiniin(IX), geraniin (X), gallic acid(XI) and ellagic acid (XII). Compound VI was found from P. urinaria for the first time and compound IX was found from genus Phyllanthus for the first time.
OBJECTIVE: To investigate the chemical constituents of Phyllanthus urinaria. METHOD: Various chromatographic techniques were employed for isolation and purification. The structures were elucidated by spectral analyses. RESULT AND CONCLUSION: A novel polyphenolic compound was isolated and named phyllanthusin F.
The L5178Y tk +/- mouse lymphoma assay (MLA) has been widely used as a genotoxicity test for the detection of mutagens and clastogens. The standard MLA, as well as other mammalian cell gene mutation assays, usually employs a short treatment period (3-6 h). Our previous report, however, suggested that such short treatments may be insufficient for detecting some clastogens and spindle poisons. For the present study, we introduced and evaluated a longer treatment (24 h) in the MLA. We examined 15 chemicals which were evaluated as negative or inconclusive in the short-term study. Cells were exposed to the chemical for 24 h without S9 mix, cultured for 2 days and then thymidine kinase-deficient mutants were selected in 96-well microtiter plates under trifluorothymidine. Eleven chemicals yielded positive responses in the 24 h treatment MLA. They included nucleoside analogs (2'-deoxycoformycin and dideoxycytidine), a base analog (1,3-dimethylxanthine) and spindle poisons (colchicine and vinblastine sulfate), all of which do not directly affect DNA, but bring about mutations and chromosome alterations through nucleoside metabolism and chromosome segregation. Because the mutagenicities of these non-DNA targeting chemicals appear to be cell cycle dependent, treatment extending over more than one cell cycle may be required for their effect. Combining results from the present and previous studies, 31 of 34 (91%) chromosome aberration-positive chemicals exhibited positive responses in the MLA, suggesting that the sensitivity of the MLA with 24 h treatment periods approaches that of the chromosome aberration test.
In this paper, the single cell microgel electrophoresis (SCG) technique was described in detail, and effects of DNA damage of human blood lymphocytes induced by gamma-rays radiation, H2O2 and CdCl2 were studied using this technique. It was shown that gamma-rays, H2O2 and CdCl2 all caused the increase of DNA migration length in the lymphocytes in the dose-dependent manner. The principle of the SCG technique, cause of DNA migration in the untreated control cells, and noticeable details in the SCG technique were also discussed.
Measles incidence data collected since 1950 in Inner Mongolia is analyzed in this paper. The following characteristics have been noticed after measles vaccine was widely used: (1) the incidence and the mortality of measles kept decreasing, (2) The epidemic still occasionally appeared at low incidence level; (3) the proportion of cases in older children increased; (4) the peak month of the disease occurrence postponed; (5) the differences of incidence among districts depending on the implementation of vaccine and immunization. Since the goal of poliomyolitis eradication is given priority to and should be achieved, measles eradication program should not be overemphasized.
The characteristics of L-arginine (L-Arg) transport in cultured aortic smooth muscle cells (SMC) of spontaneously hypertensive rat (SHR) and control WKY rats were studied and the effect of liposome as L-Arg carrier on the transport was investigated. The results showed that the L-Arg transport of SMC in SHR was obviously lower than that in WKY rats. Maximum transport velocity (Vmax) of high and low affinity in SHR were respectively 48% (P < 0.01) and 49% (P < 0.01) of WKY rat, while the michaelis constant (K(m)) showed no significant difference (P > 0.05). Increase of L-Arg transport induced by tumor necrosis factor-alpha (TNF alpha) in SMC of SHR was obviously lower than that in WKY rats (P < 0.01). The uptake of L-Arg increased 10 to 20 times in SMC when incubated with liposome encapsulated L-Arg (Liposome-L-Arg) than with free L-Arg. The transport velocity in SMC incubated with liposome-L-Arg showed no significant difference in SHR and WKY rats (P > 0.05). The transport of liposome-L-Arg in SMC was not affected by TNF alpha in both the types of rats. The above results indicate that there exists a functional disturbance in L-Arg transport in the SMC of SHR, but the L-Arg transport in SMC can be obviously enhanced when liposome is used as L-Arg carrier. Thus, it appears that liposome-L-Arg may have clinical perspective in the treatment of hypertension.
Many cytogenetic studies have been carried out on human lung cancer. However the chromosomal alterations in human lung cancers are often complex, making it difficult to identify some abnormal chromosomes by routine cytogenetic studies. Using FISH (fluorescence in situ hybridization), we studied the alterations of chromosome 2, 3, and 17 in four human bronchial epithelial cell lines, two human non-small-cell lung cancer (NSCLC) cell lines, and 12 primary NSCLC specimens. 2q- was found in three out of four human bronchial epithelial cell lines, two NSCLC cell lines, and three out of seven primary NSCLC specimens tested. 3p- was noted in five cases of twelve primary NSCLC patients examined. 3p- was the first cytogenetic discovery and the most prominent abnormality in lung cancer. 2q- has rarely been reported in human lung cancer but loss of heterozygosity by RFLP analysis for 2q had been reported in human NSCLC. Our results indicate that 2q- was also a non-random chromosomal abnormality in the early stage of the development of human NSCLC. There would be one or more putative tumor suppressor gene(s) on the long arm of chromosome 2. Loss of the gene(s) presumably contributes to the carcinogenesis of human non-small-cell lung cancer.
Light microscopic and morphometric methods along with the measurement of right ventricular systolic pressure (RVSP) and right ventricle hypertrophy index (RBHI) were performed by the authors in studying the inhibitory effects of Radix Peucedani (RP) on structural remodeling of intraacinar pulmonary arteries (IAPA) and pulmonary hypertension (PHT) in hypoxic rats. The results showed that, RP could not only antagonize IAPA contraction caused by hypoxia and lower the resistance of pulmonary circulation, inhibit the cell proliferation and hypertrophy of adventitial cells of pulmonary artery, but also reverse the change in structure and function of pulmonary artery. It suggests that RA plays a key role in inhibiting hypoxic structural remodeling of IAPA and pulmonary hypertension.
AIM: To study the effects of tetrandrine (Tet) on platelet aggregation and platelet activating factor (PAF) generation in rabbit platelet-rich plasma (PRP). METHODS: The aggregation rate of platelets induced by calcimycin (Cal) and PAF and the inhibition rate of Tet on platelet aggregation were measured. The amount of PAF in PRP stimulated with Cal and treated with Tet was also measured. RESULTS: Cal 1-8 mumol.L(-1) and PAF 9.5-190.5 pmol.L(-1) induced platelet aggregation. At the final concentrations of 4-64 mumol.L(-1), Tet inhibited the aggregation induced by Cal 4 mumol.L(-1) and PAF 142.9 pmol.L-1. The IC50 (95% confidence limits) were 8.6 (6.0-12.2) mumol.L-1 for Cal and 14.0 (6.4-30.4) mumol.L(-1) for PAF. In the PRP aggregation by Cal, there was a marked increase in PAF content. Tet dependented the release of PAF from platelets by Cal in a concentration-dependent manner, with IC50 of 21 (8-54) mumol.L(-1). CONCLUSION: The inhibition effect of Tet on platelet aggregation might be concerned with the reduction of endogenous PAF generation.
Sixty patients with endometriosis, stage I-IV, diagnosed by laparoscopy or laparotomy, were treated with 200 micrograms of domestic luteinizing hormone-releasing hormone analogue (LHRH-A) subcutaneously twice daily, starting from the early follicular phase for 6-10 months. Serum FSH and LH levels elevated at first declined significantly thereafter, and remained low after the sixth day of treatment. Serum E2 concentrations were suppressed below that of the early follicular phase or to the castrated levels after one month of therapy. Symptoms and signs of endometriosis improved markedly during the treatment and patients became anovulatory and amenorrheic. At the end of treatment, resolution of endometriotic implants and softening of adhesions were shown under the second laparoscopy. Endometrial biopsies revealed inactive endometrium. After discontinuation of the treatment, ovulatory menses returned within 34-72 days, more than half of the patients complicated with infertility for 2-10 years became pregnant within 1-8 months. The recurrence rate was 37% after 0.5-5 year follow-up. Side effects were only related to hypooestrogenism. These data indicated that LHRH-A therapy had the effect of temporary reversible medical oophorectomy, and was therefore an effective approach for the treatment of endometriosis.
A case of successful clinical pregnancy after transfer of frozen-thawed embryos was reported in this paper. The woman is a 45,XO karyotype Turner's syndrome patient with primary amenorrhea, and her husband has azospermia. She was given hormone replacement therapy to achieve adequate endometrial development. The donated embryos from two sources were frozen on April 27 and April 30, 1994 respectively. The transfer was done on May 25, 1994. Urinary beta-hCG became positive 14 days later. On July 8th, an intra-uterine embryonic sac containing an embryonic bud with good primitive heart beats was seen under vaginal B-ultrasound. Blood hCG reached 232,900 IU/L on July 25. The pregnancy is going on smoothly. The methods of freezing and thawing embryos were described.
Sclero-circular compression operation was performed on 20 unilateral rabbit eyes to make a model of intraocular hypertension which persisted for 3 days, 1, 3 and 4 weeks respectively in 4 groups of rabbits and another 4 rabbits were used as normal controls. The trabecular meshwork and aqueous plexus of the experimental rabbits' eyes were examined under transmission electron microscope on various post-operative days: 3 days, 1, 3 and 4 weeks. It was discovered that the corneo-scleral and uveal trabecular meshworks were obviously distended and their core collagenous and elastoid fibers were hyperplastic, the phenomenon being more marked with the prolongation of the duration of the intraocular hypertension. Many endothelial cells were detached from the trabecular cords and freely located in the intertrabecular spaces. Persistent hyperplasia of collagenous fibers and accumulation of extracellular plague materials occurred in the endothelial meshwork, leading to its compactness. The giant vacuoles in the endothelial cells lining the inner wall of the canal of aqueous plexus were gradually decreased in number and the cytoplasm of the cells became attenuated and some fenestrations appeared. The results show that the main site of the resistance of the aqueous outflow occurring during intraocular hypertension is at endothelial meshwork and the above experimental morphological changes are quite similar to those of glaucoma patients.
In present study, we examined the effects of NG-nitro-L-arginine (LNNA), an inhibitor of nitric oxide synthase (NOS), and/or methylene blue (MB), a blocker of guanylate cyclase on the vasodilator response of isolated rat arteries including aorta and mesenteric artery to calcitonin gene-related peptide (CGRP) by in vitro vasoconstriction experiment, and the effect of LNNA on the depressor action of CGRP by in vivo hemodynamic experiment. Furthermore, the effect of CGRP on NOS activity and cyclic guanylate monophosphate (cGMP) content were also examined by NOS activity assay and radioimmunoassay (RIA), respectively. The results showed that LNNA and/or MB significantly decreased, but not abolished, the vasodilator response of isolated rat aorta and mesenteric artery to CGRP. The depressor effect of CGRP on LNNA-induced hypertensive rats (LHR) was obviously weaker than that on spontaneously hypertensive rats (SHR), renal hypertensive rats (RHR) and normotensive rats (NWR). In addition, CGRP (0.5 nmol/kg) increased the NOS activity of rat aorta tissue by 1.3 times (P < 0.05) and resulted in an increase of cGMP content of aorta (1.27 times, P < 0.05) and myocardium (1.38 times, P < 0.05). The results suggested that NO is involved in the action of CGRP.
In order to observe the dynamic changes of hydration in galactose induced cataract, laser Raman spectrometry was used to study the water-content of lens nuclear of Wistar rats after fed them on galactose by 3, 7, 9, 11 and 17 days. The results showed that, (1) during the formation of cataract, the ratio of I3390/I2935 increased from 0.31 (3 days) to 2.26 (17 days). The water content in the nuclear was significantly increased. (2) the hydration of lens nuclear could be divided into two phases. The ratio of I3390/I2935 was increased slowly and steadily by 11 days after galactose feeding. Then, the ratio turned to increase quite fast till 17 days. It indicates that the hydration of nuclear is changed simultaneously with the formation of cataract.
A rabbit model of alkali burned cornea was made with 1 mol/L NaOH. On days 1, 3, 7 and 14 after the burn, changes in ultrastructure and the ruthenium red (RR) proteoglycan granules were as follows: (1) The epithelium and endothelium peeled off within day 1. In lightly burned cases, the epithelium regenerated on days 3-7; (2) The collagen fibers of corneal stroma became loose and irregular after the burn and began to recover with recovery of the cornea; (3) The RR proteoglycan granules decreased markedly after the burn, in light cases they increased on day 7 and gradually exceeded the normal amount, and then they reapproached the normal when the cornea was essentially recovered.
This study was based on 150 in vitro fertilization cycles carried out between June 1991 and July 1992. All the patients had blocked or dysfunctional fallopian tubes as the cause of infertility. Clomiphene citrate, human menopausal gonadotropin and hCG were used for controlled ovarian hyperstimulation. The results showed that an urinary luteinizing hormone (LH) surge (LH > 40 IU/L) occurred in 41 cycles (27.33%), a high LH level (LH = 40 IU/L) in 16 (10.67%), and normal (LH < 40 IU/L) LH level in 93 cycles, before hCG injection. The average number of oocytes recovered was not affected by the occurrence of a spontaneous LH surge, but the cleavage rate of the fertilized eggs was significantly lower than that in the cycles without LH surge and the rate of clinical pregnancy was also lower, although of no statistical significance. Our results demonstrated that the LH surge had an adverse effect on the egg quality and therefore would probably reduce the chances of pregnancy success.