Biomedical subjects
Publications and source records attributed to L Zhao.
In this article, preliminary pharmacologic studies of Qiongjiang wine are reported a comparison of this wine with Guilingji wine is made. The results show that Qiongjiang wine has the action of roborant and sex hormones. It can improve the phagocytic function of macrophage in the abdominal cavity of mice. No toxic response has been found in acute toxicity test.
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Using the reagent kits for detecting human HBV, primary serologic investigation was made in 6 kinds of domestic animals and fowls (total 673) by ELISA, spot hybridization and immuno-electronmicroscopy. The results showed that some sera samples of pigs, rabbits, chicken and geese were HBsAg, HBeAg positive and positive for spot hybridization by using 3(2)P-HBV-DNA probe, which suggested that HBV-like viruses might exist in those domestic animals and fowls. HBV-like virus particles were seen in one pig serum sample which was HBsAg positive. The particles could be divided into three forms in shape, large spherical particle (40-55nm), small spherical particle (20-30nm) and short filament particle. The further studies are needed.
A familial balanced translocation between the long arms of chromosomes 6 and 7 is described. The break points are localized to 6q27 and 7q23. No phenotypical abnormalities were found in any of the three carriers, but spontaneous abortions were frequent and might be associated with the translocation due to unbalanced segregation.
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The levels of zinc and copper in the serum, plasma, erythrocyte and urine were determined in 17 cases undergoing open-heart surgery. Samples were taken daily before, during, and after cardiopulmonary bypass operations for 9 days. Mean plasma zinc dropped significantly 30 minutes after perfusion and reached its lowest level on the first postoperative day and remained lower than the preoperative level until the seventh postoperative day. Mean urinary zinc excretion was high on the day of operation and showed a peak value 2 hours after operation. A transient decrease of plasma copper occurred after 30 minutes of perfusion. However, it returned to the preoperative level by the first or second postoperative day followed by a persistent rise to a level significantly higher than preoperative levels from the third to the ninth day. Urinary copper excretion presented the same trend as urinary zinc excretion. The results suggest that a severe loss of zinc and copper occurs in the patients undergoing open-heart surgery and a rational supply of zinc and copper is necessary.
Cardiac and respiratory functions were estimated in 16 Chinese Antarctic Research Expedition members (Third expedition) before and after spending three months in the Antarctic. No significant changes were found in ECG examination. In cardiac function test, prolonged LVET and abbreviated PEP were found. PEP/LVET decreased significantly. Respiratory ventilation function examination showed an increase in FEV1 and FEV25 and a decrease in ERC. Results showed that cardiac and respiratory functions remained almost unchanged in the Expedition members. It is also suggested that a physiological compensation may have occurred in these members' cardiac functions either in the Antarctic or during the return sea voyage.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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The diagnosis of fatty liver with magnetic resonance (MR) imaging was evaluated in experimental rat models of simple fatty infiltration and fatty liver with hepatocellular injury. T1 and T2 were measured ex vivo and correlated with the histologic degree of fatty infiltration. Enhancement of fatty liver with four different cells-specific contrast agents was studied with ex vivo relaxometry and in vivo MR imaging. Quantitative analysis of conventional and chemical shift MR images was correlated with biochemically determined fat content of the liver. Diet-induced simple fatty infiltration of the liver caused a decrease in T1 of 15%, whereas the T1 of L-ethionine-induced fatty liver with hepatocellular injury increased by 12%. T2 showed a positive correlation with the degree of fatty infiltration in both models. Cell-specific hepatobiliary contrast agents showed the same liver uptake and relaxation enhancement in fatty livers as in normal livers. Conventional T1-weighted images and chemical shift images showed good correlation (r = .83 and .80, respectively) between signal intensity and the degree of fatty infiltration. However, only chemical shift imaging was reliable in the diagnosis of fatty liver.
The efficacy for tumor detection of the hepatocyte-specific contrast agent gadobenate dimeglumine (gadolinium-BOPTA/Dimeg) was evaluated in four different experimental tumor models in rats. Histologic findings were correlated with quantitative data derived from ex vivo relaxometry and in vivo magnetic resonance (MR) imaging. Noninfiltrating tumors showed maximal enhancement of liver parenchyma 5-10 minutes after contrast agent administration, with a plateau over the next 30 minutes. In contrast, infiltrating tumors, which caused hepatocellular injury and inflammatory changes, delayed maximal enhancement of tumor-free parenchyma by 15-20 minutes. Nonspecific tumor enhancement depended on tumor vascularity and occurred in the early phase after contrast agent administration. Despite differences in specific enhancement of tumor-free parenchyma and nonspecific tumor enhancement, tumor-liver contrast-to-noise ratios increased 96%-248% in all tumor models 30 minutes after intravenous administration of 75 mmol/kg Gd-BOPTA/Dimeg. Gd-BOPTA/Dimeg enhanced tumor conspicuity independently of the histologic characteristics of the tumor.
The hepatocyte-specific paramagnetic magnetic resonance (MR) contrast agents manganese-DPDP [N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'bis-(phosphate)] and gadobenate dimeglumine were used for diagnosing chemically induced hepatitis in rats. Ex vivo liver tissue relaxation times and in vivo MR image signal-to-noise ratios were compared before and after contrast agent administration. Ex vivo relaxometry and in vivo MR imaging showed that Mn-DPDP enhanced normal and diseased livers to the same degree at all time points from 5 to 120 minutes. Gadobenate dimeglumine showed reduced T1 and T2 enhancements in hepatitis relative to those of normal liver, in the early phase (5-30 minutes). However, these effects are offsetting, and as a result, MR imaging failed to allow distinction of diseased from normal livers. This surprising result observed in vivo was in fact predicted by applying the Bloch equation to our ex vivo data. Our results show that detection and quantitation of hepatitis with MR imaging enhanced with paramagnetic cell-specific contrast agents will be more difficult than anticipated.
It is assumed that hepatobiliary, cell-specific contrast agents will be adversely affected by the presence of diffuse liver disease. The diagnostic efficacy for tumor detection in the presence of fatty liver disease was experimentally studied at contrast-enhanced magnetic resonance (MR) imaging with manganese-DPDP (N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis[phosphate]) and gadobenate dimeglumine (Gd-BOPTA/dimeg) and compared with conventional and chemical shift imaging. Carcinosarcoma was implanted into the liver of rats, and fatty liver was induced with L-ethionine. Without contrast agents, the tumor-fatty liver contrast-to-noise ratio (C/N) was increased on T1-weighted and decreased on T2-weighted MR images relative to tumor-bearing control rats without fatty liver. Chemical shift imaging (phase-contrast method) increased the tumor-fatty liver C/N from 2.3 +/- 1.0 to 6.1 +/- 1.7 (P < .001). Mn-DPDP and Gd-BOPTA/dimeg increased the tumor-fatty liver C/N from -5.4 +/- 1.6 to -11.0 +/- 1.9 and -9.8 +/- 3.4, respectively (P < .001). The hepatobiliary, cell-specific contrast agents were equally effective in both fatty and non-fatty liver and outperformed both chemical shift and conventional MR imaging in detecting liver tumors.
Previously unreported effects of tissue storage were recently observed in the authors' experimental magnetic resonance (MR) studies. To evaluate the effect of elapsed time after excision and storage temperature on tissue relaxation time measurements, tissue samples from the liver, pancreas, kidney, testis, spleen, and brain were obtained in rats. T1 and T2 were first measured within 5 minutes of excision, and between subsequent measurements, tubes were kept in a water bath at 40 degrees C, at room temperature (28 degrees C), or in an ice bath (4 degrees C). Cellular and organellar integrity was assessed with electron microscopy and correlated with the MR findings. At 40 degrees C (20-MHz spectrometer), the T1 of liver decreased from 280 msec +/- 8 to 212 msec +/- 10 during the first 60 minutes; the T1 of pancreas decreased from 276 msec +/- 3 to 208 msec +/- 2. Other tissues showed less than a 5% decrease in T1. T2 changes were smaller than T1 changes in all tissues. Electron microscopy of pancreatic acinar cells showed postmortem changes in mitochondria evolving over the first 60 minutes after death. Manganese loading experiments implicated mitochondrial manganese stores in the observed enhanced postmortem decrease in T1. This study calls into question reported relaxation time data for liver and pancreas. MR studies of excised tissues must account for time and temperature to prevent systematic experimental errors.
To study the possible effect of simulated weightlessness on brain function state, the brain event-related potentials (ERPs) in a simple visual selective response task were compared between HDT and HUT in 9 normal subjects. The results were: The Target(T) and non-Target(NT) flash signals both induced significant slow positive potentials which were supposed to related to the attention state; the amplitude of the positive potentials in frontal regions decreased significantly especially for NT-ERPs during HDT compared with that during HUT. The data reported provide new evidence indicating that more attention should be paid on the brain function study during space flight.