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Biomedical subjects

Z J Li

Publications and source records attributed to Z J Li.

At least 55 records · Page 3Linked to original sources
PubMed1992

Sudden sensorineural hearing loss induced by experimental iron deficiency in rats.

The relation between iron deficiency (ID) and sudden sensorineural hearing loss (SSHL) was evaluated in the growing rats of three different experimental groups. Fourteen rats of 132 (10.61%) that were raised on a basic ID diet showed SSHL in varied extent, from moderate to profound. By contrast, none of 128 standard control and 126 anemic control rats that were fed with the final iron-supplemented diet showed any degree of SSHL. The main cochlear correlates of SSHL in ID rats were synchronous abnormalities of the iron-containing enzymatic activity in the whole cochlea, a significant reduction of spiral ganglion cells and a rapid involvement of stereocilia of the outer and inner hair cells. The results suggest that ID can play a major role in the pathogenesis of SSHL.

Acoustic Stimulation↗
PubMed1991

Transposition of the maize activator element in transgenic rice plants.

Transposition of the maize Activator (Ac) element was observed in transgenic rice. After protoplast transformation, Ac excision from an interrupted hygromycin phosphotransferase gene was monitored by appearance of the hygromycin-resistant colonies. The frequency of Ac excision, based on the biological assay was up to 19%. Southern hybridization analysis indicated that at least one copy per genome of the hygromycin-resistance gene was reconstituted after Ac excision and that the transposed Ac element was reintegrated into the rice genome. Analysis of DNA sequences at 14 empty donor sites indicated that the Ac element was excised in rice in a similar manner as maize. The excision of an Ac mutant in which a 1.3 kbp Tn903 fragment was inserted at a unique BamHI site so as to disrupt binding of the putative transposase was not detected by DNA analysis. These results demonstrated that the maize Ac element might be used as an effective heterologous transposon for mutagenesis and gene tagging in rice, an important food crops.

Base Sequence↗
PubMed1991

Changes in T cell subsets and T suppressor cell function and their relationship in human schistosomiasis japonica.

The function of spontaneous T suppressor cell (STs) of peripheral blood was examined in 56 patients with schistosomiasis japonica at various stages. The subsets of T cell were simultaneously phenotyped in 46 cases. The percentages of CD3+ (pan T cell), CD4+ (helper/inducer T cell) and CD8+ (suppressor/cytotoxic T cell) in patients with acute schistosomiasis japonica were significantly higher than those in the normal controls. In patients with chronic and advanced schistosomiasis japonica, the percentage of CD8+ T cell and the function of STs were greatly increased, but the percentage of CD3+ T cell and the ratio of CD4+/CD8+ were obviously reduced. All of these markers changed more significantly in patients with advanced schistosomiasis japonica. The percentage of CD8+ T cell in patients with acute schistosomiasis japonica was negatively correlated with the function of STs. In patients with chronic and advanced schistosomiasis japonica the percentage of CD8+ T cell was correlated positively and the ratio of CD4+/CD8+ negatively with the function of STs. The results indicated that the cellular immunity was significantly increased in cases of acute schistosomiasis japonica and decreased in those with chronic or advanced schistosomiasis japonica. The increased CD8+ T cell may be principally cytotoxic T cells in patients with acute schistosomiasis japonica, but suppressor T cells in patients with chronic and advanced schistosomiasis japonica. The subsets of T cells and the function of T suppressor cells may play an important role in the immunoregulation of schistosomiasis japonica.

Adolescent↗
PubMed1991

Immunohistochemical detection of HBsAg and HBcAg in the liver of patients with schistosomiasis japonica complicated by hepatocellular carcinoma.

In liver biopsies from 21 patients with schistosomiasis japonica complicated by hepatocellular carcinoma (HCC), 69 patients with advanced schistosomiasis japonica, and 25 patients with HCC, HBsAg and HBcAg were investigated with peroxidase-antiperoxidase technique. The positive rate of HBAg (i.e. HBsAg and/or HBcAg) in the liver of patients with schistosomiasis japonica complicated by HCC was significantly higher than in the group of advanced schistosomiasis japonica, but similar to that in cases of HCC. The location of carcinoma cells in the liver was not related to the distribution of Schistosoma ova in patients with schistosomiasis japonica complicated by HCC. The results indicated that the complication with hepatitis B virus infection may be one of the major factors involved in the development of HCC in patients with schistosomiasis japonica.

Biopsy, Needle↗
PubMed1991

Changes in the level of IL-2, T cell subsets and the function of T suppressor cells in patients with schistosomiasis japonica.

The level of interleukin-2 (IL-2) produced by peripheral blood mononuclear cells in vitro, T cell subsets and the function of T suppressor cells (Ts) in patients with schistosomiasis japonica were investigated. It was found that the level of IL-2 induced by schistosomal antigens was significantly high and positively related to the percentage of CD4+ cells. In the groups of chronic and advanced schistosomiasis japonica, the level of IL-2 induced by schistosomal antigens was markedly lower than that in the group of acute schistosomiasis japonica, but significantly higher than that in the group of normal controls. The IL-2 level was negatively related to the percentage of CD8+ T cells and the ratio of CD4+/CD8+. The level of IL-2 induced by PHA was greatly reduced in the group of advanced schistosomiasis japonica. The changes in the level of IL-2 and its relationship with T cell subsets and the function of Ts are also discussed.

CD4-CD8 Ratio↗
PubMed1991

Temperature-sensitive mutations in the bacteriophage Mu c repressor locate a 63-amino-acid DNA-binding domain.

Phage Mu's c gene product is a cooperative regulatory protein that binds to a large, complex, tripartite 184-bp operator. To probe the mechanism of repressor action, we isolated and characterized 13 phage mutants that cause Mu to undergo lytic development when cells are shifted from 30 to 42 degrees C. This collection contained only four mutations in the repressor gene, and all were clustered near the N terminus. The cts62 substitution of R47----Q caused weakened specific DNA recognition and altered cooperativity in vitro. A functional repressor with only 63 amino acids of Mu repressor fused to a C-terminal fragment of beta-galactosidase was constructed. This chimeric protein was an efficient repressor, as it bound specifically to Mu operator DNA in vitro and its expression conferred Mu immunity in vivo. A DNA looping model is proposed to explain regulation of the tripartite operator site and the highly cooperative nature of repressor binding.

Amino Acid Sequence↗
PubMed1991

Red cell basic ferritin concentration in sensorineural hearing loss.

Red cell basic ferritin (RCBF) was measured in 62 healthy subjects with normal hearing and 224 patients with different kinds of sensorineural hearing loss, compared with serum ferritin, haemoglobin, serum iron and circadian variation in the serum iron levels. The results showed that the RCBF concentrations in most kinds of sensorineural hearing loss were significantly lower than those in normal hearing status. It is conceivable that the RCBF assay can be used to evaluate the adequacy of iron stores that are useful in times of urgent iron needs and to diagnose relative iron deficiency in those patients with some other normal laboratory assays related to iron metabolism.

Adolescent↗
PubMed1991

Noise-induced hearing loss in iron-deficient rats.

The role of iron deficiency in noise-induced hearing loss (NIHL) was evaluated in 64 rats of four different experimental groups. Iron-deficient rats (ID-rats) and normal rats (N-rats) were simultaneously exposed to a steady state white noise (20-10,000 Hz) at 110 dB SPL for 30 min. Unexposed ID- and N-rats served as controls. In N-rats the temporary threshold shifts (TTS) would have completely disappeared if the animals were allowed to survive for 72 h. No permanent threshold shift (PTS) was seen in any of the N-rats. The ultrastructural correlates in N-rats are stereocilia disarray and mitochondria swelling in outer hair cells (OHCs). The TTS in ID-rats were larger than those in the N-rats, and most ID-rats with larger threshold shifts showed varying degrees of PTSs at 11 days post-exposure. The ultrastructural correlates of NIHL in ID-rats are obvious pathology of the stereocilia, such as segmental coalescence of stereocilia of many continuous OHCs and fusion of the tips of stereocilia of OHCs, and a significant reduction of mitochondria as well as slight degeneration of nucleus in the OHCs. It is concluded that iron deficiency can provide a pathological basis for NIHL.

Anemia, Hypochromic↗
PubMed1990

Changes in the cochlear iron enzymes and adenosine triphosphatase in experimental iron deficiency.

The influences of iron deficiency on the cochlear iron enzymes and adenosine triphosphatase were studied in 68 iron-deficient rats and 68 control rats (normal and with chronic anemia). A disorderly or topographic distribution and reduction or disappearance of the cochlear succinic dehydrogenase and peroxidase reaction products were found in 37.8% of the rats fed on a basic iron-deficient diet for 14 to 100 days. The activity of cochlear sodium-potassium-dependent adenosine triphosphatase in iron-deficient rats was slightly increased, compared to that in normal controls. These results suggest that iron deficiency would produce significant abnormalities of succinic dehydrogenase and peroxidase activity, which in turn would disturb cell respiration and initiate peroxidative damage to the inner ear cells, result in sensorineural hearing loss, or provide a pathologic basis for cochlear deafness.

Anemia, Hypochromic↗
PubMed1990

Early and late results of total gastrectomy in treatment of advanced adenocarcinoma of the cardia.

Sixty-six patients with advanced adenocarcinoma of the cardia underwent total gastrectomy between 1978 and 1986. The operative morbidity rate was 7.5% and the hospital mortality rate (1 month) was 1.5%. The postoperative 1, 3, 4, and 5 year survival rates were 69%, 30.7%, 20% and 13.8% respectively. The quality of life after surgery was improved. Pathological type, lymph node metastasis, completeness of resection and postoperative chemotherapy were the main factors influencing postoperative survival time. Indications for total gastrectomy and the advantages of transthoracic total gastrectomy are discussed.

Adenocarcinoma↗
PubMed1989

[Observation on eosinophilic intranuclear inclusions in hepatocytes of patients with advanced schistosomiasis japonica].

Wedge biopsies of liver from 155 patients with advanced schistosomiasis japonica were observed pathologically, and HBsAg and HBcAg in liver were tested with double bridge peroxidase-anti-peroxidase (PAP) method. 88 of 155 cases (56.8%) were found to be HBsAg and/or HBcAg (HBAg) positive in liver. Eosinophilic intranuclear inclusions were observed in the hepatocytes of 30 cases (19.4%), in which 18 (60%) were also HBAg positive in liver. These inclusions were considered to be the markers of several virus infections, such as cytomegalovirus, herpes simplex virus, etc. The patients with positive HBAg and/or inclusion in liver had significantly more severe pathological changes in liver parenchyma. The results indicate that in addition to hepatitis B, complication with other viral infections in liver, which produce eosinophilic intranuclear inclusion, may also aggravate the pathological changes in liver and may be one of the causes of portal cirrhosis in patients with advanced schistosomiasis japonica (Fig. 1). schistosomiasis japonica

Adolescent↗
PubMed1989

[Effect of cardiac sympathetic nerves on changes of TXB2 and 6-keto-PGF1 alpha in venous blood of ischemic myocardium].

Experiments were performed on 54 anesthetized, open-chest dogs to observe the effect of cardiac sympathetic nerves and alpha- and beta-adrenoceptor blockades on changes of platelet function during the early phase of myocardial ischemia. It was shown that contents of TXB2 and 6-keto-PGF1 alpha after coronary occlusion were markedly increased, and the platelet count was reduced in the coronary venous blood of ischemic myocardium. It was found that the changes in parameters of platelet function after coronary occlusion were significantly relieved by topical application of lignocaine-soaked gauze pads to the ischemic area of the heart or by bilateral stellectomy for blocking impulse of afferent and efferent of cardiac sympathetic nerves, compared with changes in parameters of control group, P less than 0.01. On the other hand, changes in parameters of the control group could be restored by intravenous infusion of noradrenaline to dogs which bilateral stellectomy was performed on, but not by infusion of normal saline. Different effects of alpha- and beta-adrenoceptor blockades on the changes in aforementioned parameters were found. The changing degrees in elevation of TXB2 and 6-keto-PGF1 alpha and in decrease of platelet count were significantly relieved by intravenous infusion of yohimbine (an alpha 2-blocker), phentolamine (a nonselective alpha-blocker), and propranolol (a beta-blocker), but not by infusion of prazosin (an alpha 1-blocker). Results were compared with the control group, P less than 0.01. These results suggest that cardiac sympathetic nerves play an important role for the changes of platelet function during the early phase of myocardial ischemia and that, yohimbine and phentolamine may exert an improving effect by blocking alpha 2-receptors on the platelet membrane, and propranolol may directly contribute to stabilization of the platelet membrane.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Clinical and pathologic characteristics in patients with tracheobronchial tumor: report of 50 patients.

From January, 1961, to July, 1985, 50 patients in the Peking Union Medical College Hospital with intraluminal tracheobronchial tumors were operated on. There was no gender or age predominance either in the 24 patients with tracheal tumor or in the 26 patients with bronchial tumor. The 13 cell types found in these patients' specimens were divided into four groups: malignant, low-grade malignant, benign with tendency to recur and benign without tendency to recur. Squamous cell carcinoma and adenoid cystic carcinoma were the most common tumors of the trachea. Carcinoid and adenoid cystic carcinoma were the most common tumors of the bronchus in this group of patients. Conservative excision with postoperative irradiation may be sufficient for patients with advanced lesions of low-grade malignancy.

Adolescent↗