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Biomedical subjects

X Zhao

Publications and source records attributed to X Zhao.

At least 469 records · Page 26Linked to original sources
PubMed1997

[Effects of different form calcium on growth and tissue calcium level in rats].

In order to solve the problem of calcium deficiency and to look for economic and efficient source of calcium, the effects of calcium carbonate, active calcium and calcium lactate on growth, development and tissue calcium level in rats were compared. Fifty-six 3-week old weaning rats were fed with calcium deficient diet (containing vitamin D 500 IU per kg diet) for 3 weeks, and then were divided into four groups randomly with 14 rats in each group, half male and half female. The diet of control group (A) was the basic diet, while the three experiment diets were supplemented with calcium carbonate (B), active calcium (C) and calcium lactate (D) (3000 mg calcium per kg diet), respectively. The experiment term was 12 weeks. The results showed that the body weight and length of calcium supplemented group were significantly higher than that of control group (P<0.05). Among the calcium supplemented groups, no significant differences were observed except the difference of body length between the group D and the group A in female. Calcium deficiency dramatically hindered the development with reduced dietary intake and decreased food consumption efficiency. The calcium levels in plasma, red blood cells and liver were significantly higher in the supplemented groups than that in the control group (P<0.05), however, there was no difference among the supplemented groups. No significant difference of calcium levels in muscle and heart was observed among all groups. Based on needs for reaching the RDA with additional 400 mg/d from present calcium status in Chinese population, the calcium carbonate is the most economic one and the ideal calcium source for supplementation.

Animals↗
PubMed1997

[Multi-elemental analysis by preconcentration on EDTA-cellulose microcolumn coupled to ICP-AES].

EDTA-cellulose was prepared by chloroacetic acid covalently bound to filter flakes. Fe, Cu, Zn, V, Mn, Co, Ni, Al, Cd and Pb were preconcentrated on microcolumn filled with EDTA-cellulose and analyzed with ICP-AES after being eluated with dilute HNO3. At given pH value, alkali and alkaline earth metal ions can be quantitatively separated as matrix elements, and did not interfere eluate determine. High concentration factor was obtained. The usefulness of the method is shown by analyses of Standard Reference Materials.

English Abstract↗
PubMed1997

[The study of interactions of [CpFe(Co)2]2 with surface of alumina and Titania supports by Fourier transform diffuse reflection and photoacoustic infrared spectroscopy].

The diffuse reflection and photoacoustic infrared spectra of the species derived from dicarbonyl (eta5-cyclopentadienyl)iron (0) {[CpFe(CO)2]2 (Cp = eta5-C5H5)} which are supported on the surfaces of acidic,neutral and basic alumina (Al2O3) and Titania (TiO2) have been measured. The structures, stabilities and concentrations of these supported organometallic species depend markedly on the acid-base properties of the alumina surfaces. There is mainly species of [CpFe(CO)2Fe-H-Fe(CO)2Cp]+ on the surface of [CpFe (CO)2]2/Al2O3 (acidic) (A). The species of CpFe(CO)2(-O-) and [CpFe(CO)]4 are observed on the surface of [CpFe(CO)2]2/Al2O3(neutral)(B). On the suface of [CpFe(CO)2]2/Al2O3 (basic) (C), the mainly species is [CpFe(CO)2]4 with a few CpFe(CO)2(-O-) species. The concentration of species is highest on the surface of A and lowest on the, surface of C. The diffuse reflection and photoacoustic (middle and near )infrared spectra of [CpFe(CO)2]2/TiO2(T) show that the [CpFe(CO)2]2 absorbed on the surface of TiO2 is stable in the air at the room temperature. There is no a species derived from [CpFe(CO)2]2 to be observed. The diffuse reflection near infrared spectra of [CpFe(CO)2]2(D) and [CpFe(CO)2]2/TiO2 (T) are measured. Most of them are assigned to overtone and combination of carbonyl vibrations and several peaks are assigned to triple overtone and triple combination. The diffuse reflection infrared spectroscopy is the good method to study the interaction of organometallic compounds with metal oxide powder.

English Abstract↗
PubMed1997

[A resonance Raman spectrometer with UV-visible continuously tunable excitation lines].

A set of resonance Raman spectrometer with excitation lines continuously tunable in 220-970nm, which is a first set in China, has been assembled. The factors influenced on the signal noise ratio (SNR) of spectra were analyzed in detail. The methods to improve the SNR were suggested and the parameters of the spectrometer were optimized. A satisfied Raman spectra can be obtained.

English Abstract↗
PubMed1997

Interaction of ethanol with inducible nitric oxide synthase messenger RNA and protein: direct effects on autacoids and endotoxin in vivo.

Inducible nitric oxide synthase (iNOS) mRNA is up-regulated in vivo by dibutyryl-cAMP (db-cAMP), the purine-2y receptor agonist 2-methylthio-ATP and Escherichia coli endotoxin lipopolysaccharide (LPS). Ethanol and diethyldithiocarbamate inhibit LPS-stimulated iNOS mRNA. Their effects on db-cAMP- and 2-methylthio-ATP-stimulated iNOS mRNA remain undefined. We examined the effect of ethanol (4.5 g/kg intraperitoneal) and intratracheal diethyldithiocarbamate (5 mg/kg) on intratracheal LPS (0.6 mg/kg), db-cAMP (0.1 and 1 mg/kg) or 2-methylthio-ATP (5 mg/kg)-stimulated rat alveolar macrophage (AM) iNOS mRNA and protein, reactive nitrogen intermediates nitrite and nitrate anion (RNI) and nuclear transcription factor-kappaB (NF-kappaB) in vivo. LPS and the autacoids increased iNOS mRNA and protein in rat AM and RNI in bronchoalveolar lavage fluid and in ex vivo incubates of AM compared with these parameters in control rats (n = 6-21/group). Only LPS up-regulated TNF-alpha mRNA and release of TNF-alpha in bronchoalveolar lavage fluid and AM. Ethanol inhibited LPS stimulation of the iNOS cascade at the level of transcription but inhibited only autacoid-stimulated iNOS protein and RNI. Diethyldithiocarbamate selectively inhibited the LPS-stimulated iNOS cascade at the level of transcription. Coadministration of ethanol and diethyldithiocarbamate inhibited LPS-stimulated iNOS mRNA, protein and RNI more than either inhibitor alone but did not differ from ethanol alone on autacoid-stimulated iNOS protein or RNI. LPS increased and db-cAMP did not affect NF-kappaB in AM. Ethanol inhibited LPS-stimulated NF-kappaB. Thus, two distinct pathways exist for induction of iNOS mRNA in rat AM in vivo: an NF-kappaB pathway for LPS and cytokines inhibitable by ethanol and diethyldithiocarbamate and an NF-kappaB-independent pathway, refractory to inhibition by ethanol and diethyldithiocarbamate for db-cAMP and 2-mes-ATP. Finally, ethanol inhibits iNOS at the level of transcription and at the level of the enzyme.

Adenosine Triphosphate↗
PubMed1997

Ethanol inhibits inducible nitric oxide synthase transcription and post-transcriptional processes in vivo.

The effects of ethanol (ETOH) on post-transcriptional regulation of inducible nitric oxide synthase (iNOS) in vivo has not been demonstrated. We examined the effect of ETOH on iNOS mRNA, protein, and the production of the nitrate and nitrite anion (RNI) in rat lung alveolar macrophages (AM) in vivo when stimulated by lipopolysaccharide (LPS) and dibutyryl cyclic AMP (DB-cAMP). Sprague-Dawley rats (225-250 g) (n = 5-7/gp) were given intratracheal LPS (0.6 mg/kg) or DB-cAMP (0.1 and 1 mg/kg) 30 min after ETOH (4 mg/kg, intraperitoneally (ip)) or phosphate-buffered sterile saline (PBS) (5 ml/kg, ip) or pyrrolidine dithiocarbamate (PDTC 10 mg/kg, intratracheally) or 15 min after diethyl dithiocarbamate (DETC) (5 mg/kg, intratracheally). At selected times after administration of LPS or DB-cAMP, the animals were anesthetized, the lungs with the heart attached were removed and the lungs subjected to bronchoalveolar lavage (BAL). The BAL fluid was assayed for tumor necrosis factor alpha (TNF alpha) and RNI. The BAL fluid AM were isolated and analyzed for iNOS mRNA and protein with competitor-equalized polymerase chain reaction (PCR) and Western blots, respectively. The ex vivo incubates of AM were assayed for RNI and TNF alpha. LPS and DB-cAMP each increased iNOS mRNA and protein in AM and RNI in the BAL fluid and ex vivo incubates of AM. However, the peak of the increase of iNOS mRNA occurred at 2 hr for DB-cAMP and 4 to 6 hr for LPS. Only LPS increased the concentrations of TNF alpha in BAL fluid and ex vivo incubates of AM. ETOH attenuated LPS-mediated up-regulation of iNOS mRNA and TNF alpha and iNOS protein and RNI produced by the AM. In contrast, pretreatment of rats with ETOH did not affect DB-cAMP-mediated increases of iNOS mRNA in AM at any time but suppressed the amount of iNOS protein and RNI produced in DB-cAMP-stimulated AM. DETC, but not PDTC, attenuated LPS-mediated up-regulation of iNOS mRNA without effects on that produced by DB-cAMP. Since ETOH and DETC, but not PDTC, suppressed LPS-mediated but not DB-cAMP-mediated transcription of iNOS, we conclude that two distinct pathways exist for induction of iNOS mRNA by these agonists. ETOH and DETC may inhibit the LPS-mediated activation pathway by acting as antioxidants. Also, since ETOH inhibited DB-cAMP-mediated increases in iNOS protein without affecting iNOS mRNA ETOH also acts at a post-transcriptional or translational site to inhibit iNOS protein in rat AM in vivo.

Animals↗
PubMed1997

Phase II trial in China of a new, rapidly-acting and effective oral antimalarial, CGP 56697, for the treatment of Plasmodium falciparum malaria.

One hundred and two Chinese out-patients with naturally acquired, previously untreated, falciparum malaria were selected to evaluate the efficacy of a new combination anti-malaria therapy, CGP 56697 (artemether plus benflumetol). In this open non-comparative trial each patient received a combination of 80 mg artemether and 480 mg benflumetol given orally at 0, 8, 24 and 48 hours (total: 320 mg artemether, 1,920 mg benflumetol). Patients were kept for 28 days in a transmission-free hospital in an area with chloroquine resistant falciparum malaria to prevent reinfection and to aid diagnosis of recrudescence. Progress and possible adverse effects were monitored by blood film parasitology, blood biochemistry assays, urinalysis, ECG and X-ray. Ninety-eight of the 102 patients were shown to be free of infection at 28 days, a 96.1% cure rate. Parasite reduction at 24 hours was 99.4%. Time to effect complete parasite clearance ranged from 24 to 54 hours (median 30 hours). Time for fever clearance ranged from 6 to 78 hours (median 18 hours). Recrudescence was low (3.9%). No significant adverse side-effects were encountered. It is concluded that CGP 56697, a combination anti-malaria therapy of artemether with benflumetol, offered a rapid and highly effective treatment for acute uncomplicated falciparum malaria in an area of chloroquine-resistant malaria in China.

Administration, Oral↗
PubMed1997

Percutaneous transluminal coronary angioplasty for acute myocardial infarction: initial experience in 43 cases.

OBJECTIVE: To evaluate the initial experience with the use of percutaneous transluminal coronary angioplasty (PTCA) in the set of acute myocardial infarction (AMI). METHODS: Between October 1993 and April 1996, PTCA was performed in 43 patients (34 male, 9 female) with initial onset of AMI. These patients ranged in age from 40 to 74 years (mean +/- SD, 60.3 3 +/- 9.2). Primary PTCA was performed in 16, rescue PTCA in 8, and semi-elective PTCA in 19 patients. RESULTS: The initial success was achieved in 95.3% (41/ 43). Failed angioplasty occurred in 2 patients, with acute reocclusion after rescue PTCA (this patient died of cerebral stroke 3 days later) in one patient, and small local intimal dissection during semi-elective PTCA in another patient. CONCLUSION: PTCA was a safe and effective approach in the treatment of AMI in the present study patients, with a high primary success and low acute complication rate.

Adult↗
PubMed1997

[Establishment and characterization of a xenografted human cervical carcinoma in nude mice and homologous cell line in vitro].

OBJECTIVE: To establish a xenografted tumor strain of human cervical carcinoma in nude mice and homologous cell line in vitro. METHODS: A human well differentiated cervical squamous cell carcinoma derived from a surgical specimen was transplanted in the subcutis of nude mice. The xenograft was cultured to establish a cell line in vitro. A series of characteristics of the grafts and the cells were examined. The established cell line was cloned by single cell detaching flask. Non-serum culture of the cells was tried. RESULTS: The xenografts were successively passaged for 26 generations during a period of 17 months. A tumor strain HCC-94V was established, having a high rate of successful inoculation rate (92.9%) and was growing steadily. The morphological and biological characteristics of its original tumor were preserved. The chromosomal analysis revealed a human aneuploid pattern of 9-120 in number. The tumor markers detected by immunocytochemical techniques showed high expression, the oncogenic products, low expression. Polymerase chain reaction (PCR) showed the same results as those of the patients with original tumor tissue, human papilloma virus (HPV) 16 (+), 18 (-). A new human cell line HCC-94 derived from the xenograft, was established and maintained for 16 months through 131 passages. Transmission electromicroscopy demonstrated the presence of typical desmosomes between the cells and many tonofilaments in the cells. Also, the morphology of chromosomes showed the characteristics of chromosomes as well as of mutants in the human tumor cells. The tumor markers and the oncogenic products of the cells exhibited higher expression than that of the original tumor. The HPV 16 and 18 of the cells, using PCR, were negative. The cells were highly tumorigenic in nude mice. The transplanted tumors resembled the original tumor tissues in morphology and were HPV 16 positive. Both cell cloning culture and non-serum culture of HCC-94 were successful. CONCLUSION: HCC-94V and HCC-94 could be considered as a new xenografted tumor strain may provide material and model ideal for further investigation of human cervical carcinoma.

Adult↗
PubMed1997

[Application of ultra-short gonadotropin-releasing hormone agonist protocol in controlled ovarian hyperstimulation].

OBJECTIVE: To study the effect of the ultra-short protocol of gonadotropin releasing hormone agonist (GnRH-a) combined with human menopausal gonadotropin (hMG) regimen for ovarian hyperstimulation. METHODS: Setting clomiphene (CC)/human chronic gonadotropin (hCG) (50 cycles, 31 patients) and CC/hmg/hCG regimens (16 cycles, 16 patients who had failed in CC/hCG) as control groups, the ultra-short GnRH-a/hMG/hCG regimen (15 cycles, 15 patients who had failed in CC alone or CC/hMG regimens) as study group, the number of leading follicles, endometrial thickness, cervical mucus scores and hormone levels on the day of hCG administration, and the pregnancy rates were compared among of these three groups. RESULTS: There was no premature luteotropic hormone (LH) surge in the ultra-short GnRH-a/hMG/hCG regimen group while there were three cycles in the CC/hMg/hCG group. The LH and progesterone (P) levels of ultra-short GnRH-a/hMG group on the day of hCG administration were lower than those of CC alone and CC/hMG groups. There were more leading follicles, greater endometrial thickness and cervical mucus score in the ultra-short GnRH-a/hMG group than those in CC alone and CC/hMG groups. The pregnancy rates per cycles in the three groups were similar. CONCLUSION: The ultra-short GnRH-a/hMG regimen is a fairly good ovarian hyperstimulation regimen, especially for poor responders in CC alone or CC/hMG regimens.

Adult↗
PubMed1997

[Effects of deltamethrin on the binding of glutamate receptor to rat cerebral cortical synaptosomal membrane].

Effects of deltamethrin on the binding function of glutamate receptor of cerebral cortical synaptosomal membrane in rat were studied by radio-labeled ligand receptor binding assay. Results showed that deltamethrin could obviously increase the 3H-glutamate binding to synaptosomal membrane, by doses of 1 x 10(-8) to 1 x 10(-4) mol/L, with a dose-dependent relationship. Glutamate binding rate increased by 3.2 percent to 13.5 percent in deltamethrin treated group, as compared with dimethyl sulfoxide solvent controls. Binding dynamic analysis of receptor and ligand showed that an obvious synergistic action of deltamethrin and dimethyl sulfoxide. It indicated that neurotoxicity of deltamethrin could be related to the disturbance of central transmitter system of glutamate.

Animals↗
PubMed1997

[Effects of lead on the release of glutamate neurotransmitter in rat hippocampal slices].

Effects of lead on the release of glutamate neurotransmitter were observed in rat hippocampal slices in vitro to study its neurobiological mechanism of lead-induced impairment in learning and memory function. Results showed that exposure to 3.1 to 50.0 mumol/L of lead could cause a dose-dependent increase in spontaneous release of 3H-DL-glutamic acid in hippocampal slices by 23.2% to 66.2% in the absence of calcium. However, in the presence of calcium, spontaneous release of 3H-DL-glutamic acid decreased by 22.6% to 55.3% with increase of exposure to lead from 1.0 to 50.0 mumol/L, and the release induced by potassium increased by 89.3% to 332.1% with a dose-response relationship. It indicated that exposure to lead could interfere with spontaneous and induced release of glutamate transmitter.

Animals↗
PubMed1997

[Activation of glutamate uptake in rat hippocampal synaptosome by lead].

In order to investigate the mechanism of effects of lead on learning and memory, an experiment of glutamate uptake in the hippocampal synaptosome of rats was carried out. Results showed that (1) uptake of 3H-DL-glutamate increased by 70.38% to 193.24% in the synaptosome by exposure to 3.1 to 50.0 mumol/L of lead for 15 minutes in vitro, with a dose-dependent relationship; and (2) uptake of 3H-DL-glutamate increased by 65.73% to 124.93% after exposuring to 10 to 1,600 micrograms/ml of lead in drinking water for 30 days, also in a dose-dependent manner with lead content in the hippocampus. It suggests that lead ion can accelerate the clearance of glutamate transmitter and cause inhibitive effects.

Animals↗
PubMed1996

Cationic lipid-mediated NGF gene transfection increases neurofilament phosphorylation.

We examined the effect of cationic lipid-mediated gene transfection of nerve growth factor (NGF) in primary septo-hippocampal cell cultures. Rat NGF cDNA was subcloned into a pUC19-based plasmid containing a CMV promoter. Two days after NGF gene transfection in primary cell cultures, ELISA confirmed increases in NGF protein secretion from transfected cells. To study the biological effect of cationic lipid-mediated NGF gene transfection, we analyzed the amount of neurofilament protein from NGF-transfected cell cultures. Western blot and immunohistochemical analyses detected significant increases in the phosphorylated form of neurofilament proteins in the cultures after cationic lipid-mediated NGF cDNA transfection. Cationic lipid-mediated NGF cDNA transfection did rot cause significant changes in the total amount of neurofilament protein. Our studies suggest that cationic lipid-mediated NGF gene transfection can increase neurofilament phosphorylation but not total neurofilament protein.

Animals↗
PubMed1996

Putative human blue-light photoreceptors hCRY1 and hCRY2 are flavoproteins.

Recently, a human cDNA clone with high sequence homology to the photolyase/blue-light photoreceptor family was identified. The putative protein encoded by this gene exhibited a strikingly high (48% identity) degree of homology to the Drosophila melanogaster (6-4) photolyase [Todo et al. (1996) Science 272, 109-112]. We have now identified a second human gene whose amino acid sequence displays 73% identity to the first one and have named the two genes CRY1 and CRY2, respectively. The corresponding proteins hCRY1 and hCRY2 were purified and characterized as maltose-binding fusion proteins. Similar to other members of the photolyase/blue-light photoreceptor family, both proteins were found to contain FAD and a pterin cofactor. Like the plant blue-light photoreceptors, both hCRY1 and hCRY2 lacked photolyase activity on the cyclobutane pyrimidine dimer and the (6-4) photoproduct. We conclude that these newly discovered members of the photolyase/photoreceptor family are not photolyases and instead may function as blue-light photoreceptors in humans.

Amino Acid Sequence↗
PubMed1996

Very low rates of hip fracture in Beijing, People's Republic of China the Beijing Osteoporosis Project.

One third of the world's hip fractures are said to occur in Asia, mostly in China. However, there have as yet been no validated studies of hip fracture rates in China. The authors estimated the incidence of hip fractures in Beijing, People's Republic of China, and took several steps to validate the estimates. All 76 Beijing hospitals reported all 1988-1992 admissions that had been coded as 820 (hip fracture) or 821 (other femoral fracture) according to the International Classification of Diseases, Ninth Revision. The authors then compared a random sample of the reports with original medical records, and discovered that 70% of intertrochanteric hip fractures had been miscoded as "other femoral fractures." The authors retrained all hospital staffs to provide corrected reports. Revised reports missed only 13% of the hip fracture cases recorded in operating room logs of 11 randomly selected hospitals. To validate hospital-based estimates of hip fracture rates, the authors interviewed a random sample of 2,113 Beijing women aged 50 years or more (97% response rate); all but 4% of past fractures and all seven hip fractures had been treated in hospitals. Finally, the authors surveyed the 27 hospitals in the counties surrounding Beijing. No Beijing residents had been treated for hip fracture outside of the city. Based on the 1990 China census, age-standardized rates of hip fracture (per 100,000) in Beijing-87 for women, 97 for men-were much lower than those seen in Hong Kong in 1985 (353 for women, 181 for men) or in US Caucasians (510-559 for women, 174-207 for men). From 1988 to 1992, the rates in Beijing increased 34% in women and 33% in men. The authors conclude that hip fracture rates in Beijing are among the lowest in the world but may be rising rapidly.

Adult↗