Biomedical subjects

G Zhao

Publications and source records attributed to G Zhao.

At least 181 records · Page 10Linked to original sources

PubMed1998

[Magnetic resonance imaging with multiplane histomorphometry in avascular necrosis of femoral head: analysis of trabeculae].

OBJECTIVE: To distinguish the differences of changes of bone trabecular structure between high and low signal area which could directly reflect the mechanical strength and estimate the risk of collapse in avascular necrosis of femoral head (ANFH). METHODS: After total hip replacement, the specimen of ANFH was scanned by MR imaging. Accurate localization, consecutive slicing, multiplane histomorphometry, correspondence of MR images with slices were used. Mean trabecular width (MTW micron) and mean trabecular space (MTS micron) were selected as observation indexes. RESULTS: MTW in the low signal area was lower than that in the high signal area. MTS in the low signal area was higher than that in the high signal area. The results indicated that the dispersive degree of bone trabeculae was higher in the low signal area. CONCLUSION: Bone trabeculae in the low signal area necrosed and atrophied so that the bone volume and mechanical strength of trabeculae declined and bone trabeculae in the low signal area were liable to microfracture and collapse.

Femur Head↗

PubMed1998

[The characteristics and significance of oncogenes expression in oval cells cultivated in vitro].

OBJECTIVE: To study the relationship between expression characteristics of oncogenes and transformation of the oval cells cultivated in vitro. METHODS: Liver oval cells of SD rats induced by feeding with chemical carcinogen 3'-Me-DAB for four weeks were isolated using Percoll density gradient centrifugation. The cells were continuously cultivated in vitro and the dynamic characteristics of Ha-ras, Ki-ras and c-myc genes expression in the oval cells were detected using RNA-DNA slot blot hybridization. RESULTS: During long term cultivation, the population doubling time of the cells became shorter and the percentage of aneuploidy chromosomes and colonies grown in soft agar increased. Ha-ras Ki-ras and c-myc were synchronically expressed in the oval cells from different passages. CONCLUSION: The activation and synergistic over-expression of Ha-ras Ki-ras and c-myc had an important role in the proliferation and transformation of oval cells in vitro.

Animals↗

PubMed1998

[Experimental study on inhibitory effect of ganlu xiaodu Dan on coxackie virus in vitro].

OBJECTIVE: To observe the Coxackie virus inhibitory effect of Ganlu Xiaodu Dan (GLXDD), including complete recipe, incomplete recipe and supplemented recipe of it. METHODS: Using tissue culture technique, the maximal non-toxic concentration of drug on cultured cells, the influence of drug on proliferation of virus in cultured cells and the virus inhibitory effect in different time of action were observed. RESULTS: The maximal non-toxic concentration of GLXDD was 1:40 (25 g/L), no matter whether the recipe was complete, incomplete or supplementary. CLXDD in that concentration could inhibit significantly the proliferation of Coxackie virus B2, B3 and B4 strains, the inhibition index being over 2 and the output of these strains treated with complete recipe of GLXDD was lower significantly than that of the control group (P < 0.05). CONCLUSION: GLXDD, including its complete recipe, incomplete recipe and supplementary recipe, could inhibit the replication of Coxackie virus in cultured cells.

Antiviral Agents↗

PubMed1998

[Separation and determination of eight plant hormones by reversed-phase high performance liquid chromatography].

In this paper, reversed-phase high performance liquid chromatographic technique was used for the separation and determination of eight plant hormones. Methanol-water-acetic acid system was chosen as the mobile phase. The effects of different separation conditions, such as the methanol and acetic acid concentrations in mobile phase, on the retention behaviours of eight plant hormones in this system were studied. The general trends in retention behaviours could be correlated to the methanol concentration in mobile phase. The experimental results showed that the optimum separation was achieved with following gradient elution condition: 0-3 minutes, 70% (water percentage in mobile phase), 3-13 minutes, 70%-20%, 13-48 minutes, 20%. Benzene was added to be as the internal standard. Under this experimental condition, the eight plant hormones could be separated completely and detected quantitatively at 260 nm within 16 minutes. The calibration curves for the eight compounds gave linearity over a wide range. The correlation coefficients of each components were r(ZT) = 0.9971, r(GAs) = 0.9999, r(K) = 0.9997, r(BA) = 0.9995, r(IAA) = 0.9998, r(IPA) = 0.9982, r(IBA) = 0.9995 and r(NAA) = 0.9995. The method is rapid, simple and efficient. It is a suitable method for the accurate determination of gibberellic acid (GA) and alpha-naphthaleneacetic acid (alpha-NAA) in products for agricultural use.

Chromatography, High Pressure Liquid↗

PubMed1998

[Nonlinear dynamic analysis of heart rate variability during exercise].

Nonlinear dynamic analysis was used to examine the changes of complexity of heart rate variability (HRV) under rest and exercise. Nine healthy male subjects participated in the test. Each subject had a rest in supine position for 10 min, and then exercised on a cycle ergometer (10 min at 50 W and 10 min at 100 W). The results showed that R-R interval and its standard deviation reduced, and at the same time the values of nonlinear dynamics indices (complexity, entropy, correlation dimension, capacity dimension) also decreased during exercise. Moreover, at 100W work load the decrease of these indices was greater than that of 50W. It shows that physical exercise may reduce the complexity of HRV, and nonlinear dynamic indices could be used in distinguishing the complexity of heart rate variability under different physiological conditions.

Adult↗

PubMed1998

Linear and nonlinear analysis of heart rate variability during lower body negative pressure.

In order to measure the changes of heart rate variability (HRV) under lower body negative pressure (LBNP), time and frequency domain parameters as well as the relative LZ Complexity were used to analyse HRV. Fifteen healthy male subjects in supine position were subjected to sequential LBNP (-2.7 kPa 2 min, -4.0 kPa 3 min, -5.3 kPa 5 min, -6.7 kPa 10 min). They were divided into two groups: intolerant group (group A) and tolerant group (group B). There was a similar decreasing trend for R-R interval at -5.3 kPa and -6.7 kPa in both groups. Spectral analysis showed no significant alternations in both groups. At -6.7 kPa, complexity showed significant differences from the baseline values in both groups. Furthermore, there was a more significant reduction of complexity in group A than that in group B. These results showed that LBNP is associated with a decrease of HRV complexity. In addition, this study suggests that nonlinear dynamics measurement of heart rate variability may provide a sensitive index in the regulation of cardiovascular system.

Adult↗

PubMed1998

[Changes of cervical blood flow in subjects with different tolerances to -30 degrees head-down bed rest].

In order to investigate characteristics of cervical blood flow in subjects with different tolerances to head-down tilt (HDT), 40 healthy men (aged 26-35 years) participated in the test of -30 degrees HDT for 45 min. During the test, mean blood flow velocities, diameters and blood flow volume of common carotid artery (CCA), Internal carotid artery (ICA), Internal jugular vein (IJV) were measured with color Doppler echogram. The results showed that there have different changes of in-flow of ICA and out-flow of UV between the adaptive subjects (n=33) and the inadaptive subjects (n=7). In the adaptive group, the cerebral blood flow volume during HDT, did not change from that during horizontal supine position. However, in the inadaptive group in-flow of ICA increased and out-flow of IJV decreased significantly during HDT as compared with those during horizontal supine position.

Adaptation, Physiological↗

PubMed1998

[Anaerobic threshold as determined by gas metabolic parameters].

In order to demonstrate the possibility of evaluating anaerobic threshold (AT) by gas exchange parameters, treadmill exercise tests were made by 1-min increment protocol in 25 healthy young men. Ten parameters of gas exchange were collected when AT was reached. The analysis showed that correlation between VO2 and VE (r = 0.8004) or VCO2 (r = 0.9743) are high. While correlation between VO2 and RQ (r = 0.4491) or HR (r = 0.4666) are significantly lower. So the accuracy of VE and VCO2 is higher than that HR or RQ for the determination of AT.

Adolescent↗

PubMed1998

[Relationship between hematocrit (Hct) and cardiac systolic time intervals (STI) in residents at 4300 m altitude].

In order to study the relationship between Hct and cardiac systolic time intervals (STI) in residents at high altitude, STI and cardiac function were determined by electrical impedance and carotid arteriogram in 113 subjects with different Hct at an altitude of 4300 m. There was a negative correlation between Hct and SV or EF (r = -0.841 and -0.628), respectively (P < 0.001). With increase of Hct there were prolonged pre-ejection period (PEP), shortened left ventricular ejection time (LVET), and increased PEP/LVET. SV, CO were lower in high altitude polycythemia (HAPC) than in the control (P < 0.05). It demonstrated that there is a close relationship between STI and Hct, and excessive polycythemia is one of the important factors that cause decrease of cardiac function decreasing in high altitude residents.

Adolescent↗

PubMed1998

[Heart rate variability analysis under lower body negative pressure].

In order to assess the changes of HRV in relation to hemodynamic responses to LBNP, 40 healthy male volunteers were exposed to progressively increasing LBNP. Changes of SV, CO and BP were measured and HRV was analyzed. Thirty-four subjects (Group A, with good tolerance) were able to tolerate all stages of LBNP, and other 6 subjects (Group B, with poor tolerance) showed presyncopal signs and symptoms during the last 5min of LBNP exposure. In both groups, HRV, SV, CO decreased significantly during LBNP. Group B had lower HRV, SV, CO than group A pre-LBNP, during-LBNP and post-LBNP. The LF/HF ratio increased during LBNP in both groups, but increased more apparently in group B than group A at -6.7 kPa LBNP. The results showed that, when SV decreased to a certain degree, the sympathetic activity increased to the utmost. The onset of presyncopal signs could be attributed to the rapid withdrawal of sympathetic tone, and LBNP tolerance of a subject is closely related to both ejecting capability of the heart and the function of autonomic nervous system.

Adult↗

PubMed1998

[Bilateral ureter within single nipple for cutaneous ureterostomy after radical cystectomy].

OBJECTIVE: To evaluate the effect of bilateral ureter within single nipple for cutaneous ureterostomy after radical cystectomy. METHOD: Bilateral ureter within single nipple for cutaneous ureterostomy was performed on 36 patients after radical cystectomy. RESULT: The nipple was formed well, and urinary drainage was patent. No death or severe complication occurred. The patients have been followed up for 3 months to 3.5 years. Urinary, electrolyte and renal functions were within normal levels. No pyelonephritis or hydronephrosis was observed in IVP, retrograde pyelography and/or sonographic examination of kidneys, no nipple constriction. A right ureter was pulled to the left retroperitoneum and formed a nipple with ureter left on the left abdominal wall. CONCLUSION: This is a simple and safe operation, especially suitable to the old and weak patients.

Adult↗

PubMed1998

[Histological changes of Cysticercus cellulosae under the action of proteinase of Omphalia lapidescens in vitro].

AIM: For the purpose of finding an anthelmintic with high efficacy, low toxicity and low cost, especially from the Chinese traditional medicines. METHODS: Forty Cysticercus cellulosae were separately incubated with proteinase from artificially fermented Omphalia lapidescens for 2 h, 4 h and 8 h, and then examined for histological changes by light microscopy and compared with those of proteinase from natural dry Omphalia lapidescens after similar treatment. RESULTS: Cysticercus cellulosae were morphologically and structurally impaired after exposure to the action of proteinase of Omphalia lapidescens, and the degree of impairment was proportionally paralleled to the duration of treatment. CONCLUSION: The anti-cysticercus effect of proteinase of Omphalia lapidescens and the homogeneity of proteinases from artificially fermented and natural Omphalia lapidescens were confirmed.

Animals↗

PubMed1998

[The morbidity investigation of residents in a highly endemic village of schistosomiasis in Poyang Lake region].

AIM: To investigate the morbidity of residents in a highly endemic village of schistosomiasis, and to evaluate the usefulness of ultrasound in morbidity study. METHODS: Morbidity induced by Schistosoma japonicum was evaluated and compared in target population by using parasitological examination, ultrasound investigation and medical history questionnaire. RESULTS: The schistosome infection rate was 22.9% in the study population and the prevalence of abnormal ultrasound findings in the liver and spleen was high. The abnormal ultrasound findings correlated with sex significantly, the abnormality of liver parenchyma correlated with age, sex, infection status, occupation and the number of treatment after multiple logistic regression analysis. CONCLUSION: The ultrasound examination could find out the direct pathological changes resulting from schistosome infection.

Adolescent↗

PubMed1998

[Studies on the oxidation reaction of octanol-2 with nitric acid by infrared spectroscopy].

In this paper, the reaction process of oxidation of octanol-2 with nitric acid has been studied by IR spectroscopy. It is found that the main components of non-sapoifiable matter are different in different oxidation degrees. The relation between oxidation products and the amount of nitric acid are investigated,the reaction mechanism has also been studied. Experimental results show that the oxidation process of octanol-2 is as follows: first, octanol-2 is oxidated to octanone-2, or to nitrate, nitrite and nitrile copmpounds, then these compounds are reoxidated to caproic acid in the meantime some by-products, such as valeric, enanthic acids are also found in oxidated products.

English Abstract↗

PubMed1998

[An application of genetic algorithms to the analysis of EXAFS spectrum].

Extended X-ray absorption fine structure (EXAFS) has been extensively used in the structural study in recent years. But the current methods of analysis EXAFS spectrum is difficult and tedious,demanding either very similar standard samples or the initial parameters near the solution. In this paper, a new technique Genetic Algorithms (GAs), was applied to the analyzing of the EXAFS spectrum,and two spectra of CU samples were investigated by the method. It was found that reasonable results can be obtained by the method only with limiting the initial parameters to a broad range. Comparing the results with those obtained by EXCURVE88, the fitting is superior, and the parameters are reasonable. Therefore, it is proved that the GAs may be a high performance method for the analyzing of the EXAFS spectra.

Algorithms↗

PubMed1998

[Photoacoustic spectra of La (III), Gd (III), Tb (III) 8-hydroxyquinoline complexes and relaxation process].

8-hydroxyquinoline complexes of La(III) Gd (III) and Tb (III) were synthesized and the photoacoustic (PA)spectra of these complexes were measured in the region of 300-800nm at room temperature. The PA spectra and excitation spectra are compared and interpreted. It is observed that the photoacoustic spectra and the excitation spectra behave complementarily. The different fluorescence properties of the complexes and the relaxation process models are studied by the photoacoustic amplitude and phase spectra. It is confirmed by the PA phase spectrum that the PA absorption of pi-pi* transition of Tb (Ox)3 complex is dominantly contributed by the slow radiationless relaxation which is due to inner-molecular energy transfer.

English Abstract↗

PubMed1998

Thyroid injury, autoantigen availability, and the initiation of autoimmune thyroiditis.

Iodine depletion prevents disease and iodine repletion, which may cause thyroid cell injury by reactive oxygen intermediates, initiates disease in the Obese Strain chicken model of spontaneous autoimmune thyroiditis (AT). To examine the role of cell injury and autoantigen availability in AT induction we compared the immune responses that followed blunt trauma to the OS thyroid in the absence of iodine and the administration of normal dietary iodine in the absence of thyroid injury. Serum thyroglobulin concentrations were elevated following thyroid injury and the extensive thyroid infiltrates had high macrophage/CD4+, CD8+, B cell ratios consistent with an acute inflammatory response. The response was self limiting and undetectable in all animals 2 weeks later. Birds raised on a similar low iodine regimen were withdrawn from the regimen and given normal dietary iodine. Their thyroids showed no evidence of acute ultrastructural damage. The resulting early thyroid infiltrates had low macrophage/CD4+, CD8+, B cell ratios. Two weeks later these animals showed severe thyroid infiltration (43%) and after 4 weeks all animals had >90% infiltration. Thus, the presence or absence of thyroidal iodine, whether accompanied by injury or not, determined the nature and consequence of the immune response which argues against hypotheses that include obligatory injury at disease onset. Taken with previous work, this study suggests that iodination of an autoreactive thyroglobulin epitope is a requisite pathogenic action of iodine and supports the notion that in some organ-specific autoimmunity, a component of the dysregulation is associated with aberrant activity of the target tissue.

Age Factors↗

PubMed1998

[The genetic analysis of amplitude of progesterone secretion in serial blood collection from tail in min sows].

28 adult Min sows (3-7 parities), represented 9 sire families were selected to conduct the continual blood collection from the tail for two hours at the interval of ten minutes between 9:00-11:00 in the morning on the sixth day after the last mating. The content of progesterone was assayed by radio-immunological assay. The amplitudes of the secretion of progesterone were generated by the procedure of HORM fft. exe complied by the author. It is difficult to get a reasonable conclusion from the content analysis, because the content varied widely between different points of blood collection in single sow. After Fourier conversion, the heritability of amplitude for the fifth partial wave was high (h2 = 0.932); middle for the basal, 2nd and 3rd partial waves; lower for others. This supported the idea that prolific sows had more active secretion of progesterone in luteal cells. The coexist of low and high heritability components in amplitude of progesterone secretion showed that the activities of progesterone secretion were influenced by both the genetics and environments. The genetic correlation of basal, 1st, 5th partial waves were negative, the others were positive, with the litter size and litter size alive. It showed that the reproductive performance of Min pigs were not expressed perfectly, as the balance of secretion of progesterone did not reach the best. The genetic correlation of all partial waves with duration of estrus was negative which supported that the progesterone suppresses the estrus. The genetic correlation of 3rd, 5th partial waves were stronger than others, but selection for 5th partial wave would make high responses than the 3rd wave, because the genetic correlation of 3rd partial wave with litter size and litter size alive was positive, therefore, the more appropriats method of selection for progesterone was adopted, the better results would be achieved in the improvement of indirect selection response for litter size.

Animals↗