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Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 685 records · Page 38Linked to original sources
PubMed1996

[Effects of freezing and hypoxia on serum creatine kinase activity in rats].

Serum creatine kinase (CK) activity after cold exposure in rats acclimated to cold, hypoxia, or combined factors (both cold and hypoxia) were observed under normoxic [correction of normoxie] and hypoxic condition in order to study the degrees of damage to the tissues. The results showed that resistance to frostbite increased in rats acclimated to cold; resistance to frostbite decreased markedly in rats acclimated to hypoxia, i.e. negative cross-acclimation exists between hypoxia and cold. The changes in serum CK activity in rats exposed to both cold and hypoxia for 4 weeks were essentially the same as those in hypoxia-acclimated rats, and were different significantly from those in cold-acclimated rats. It indicates that the effects of hypoxic exposure were stronger than those of cold exposure, its mechanism remains an area for further study.

Acclimatization↗
PubMed1996

[Clinical summary of relatively large dose of sodium morrhuate injection for the treatment of maxillofacial cavernous hemangionma:A report of 764 cases]

The result of relatively large dose of 5% sodium morrhuate injection(SIM) for the treatment of 764 cases in the cavernous hemangioma in orofacial region is presented.The curative rate was improved,Its cure and elementary cure rate were 89.27%.The dosage,course and practical approach were discussed,The relationship of factors listed above with the curative effect were mentioned.The reaction and complications might be influencing the recurrence rate.Hemangioma after SMI should be observed in order to consolidate its curative effect.

Journal Article↗
PubMed1996

Gangliosides of migrating and nonmigrating corneal epithelium in organ and cell culture.

PURPOSE: To identify major gangliosides - the sialated glycolipids - of corneal epithelium; to determine which specific gangliosides, if any, are synthesized in a higher amount or are downregulated during corneal epithelial cell migration; and to determine what role, if any, they play in the modulation of corneal epithelial cell proliferation. METHODS: [3H]-galactose-labeled and unlabeled glycolipids of migrating and nonmigrating rabbit corneal epithelium in cell and/or in organ culture were chromatographed on DEAE Sephadex to isolate gangliosides. The gangliosides eluted from the ion-exchange column were further characterized by thin-layer chromatography (TLC), glycosidase digestions, and TLC-immunostain analysis. A [3H]-thymidine incorporation assay was used to determine the effect of exogenous gangliosides on corneal epithelium cell proliferation. RESULTS: Upon TLC of the acidic fraction eluted from the DEAE column, only two radiolabeled glycolipids (GL1 and GL2), migrating as a doublet, were detected. Regardless of whether the epithelia were prepared by cell culture or organ culture, both GL1 and GL2 were present in a significantly higher amount in migrating compared to nonmigrating epithelia. Further characterization of GL1 and GL2 identified them as gangliosides known as GM3. TLC-immunostain analysis, as well as orcinol staining of thin-layer chromatograms of gangliosides of unlabeled cells, revealed that GM3 also accumulates in a higher amount in migrating compared to nonmigrating epithelial cell cultures. Exogenous addition of GM3, but not various other gangliosides, inhibited corneal epithelial cell proliferation in a dose-dependent manner. CONCLUSIONS: GM3 is the major ganglioside present in corneal epithelium, and its levels are elevated during corneal epithelial cell migration. It is suggested that the ganglioside plays a role in events that modulate corneal epithelial cell proliferation.

Animals↗
PubMed1996

Studies on lung injuries caused by blast underpressure.

This study was designed to determine the effects of underpressure on the lungs of rats and rabbits. An underpressure generator was made to simulate reliably the underpressure parameters at various levels. The peak level and duration ranged from -45.5 kPa to -86.5 kPa and from 21.3 milliseconds to 1,900 milliseconds, respectively. The time to peak negative pressure ranged from 3.5 milliseconds to 7.4 milliseconds. The results showed that underpressure at a certain level could inflict injuries on rats and rabbits. The severity of injury ranged from mild to extremely severe, even to death. These injury patterns were similar to those induced by blast overpressure. The lungs were the organs most vulnerable to underpressure. The pulmonary pathological changes included hemorrhage and edema. The typical hemorrhagic stripes on the lung surfaces resulted from the interfacial impacts of the lungs on the chest wall. The severity of lung injury increased with increased peak pressure and duration levels. This relationship can be expressed with linear regressive equations and the physical parameters of the underpressure can be used to indicate the severity of injury to lungs.

Animals↗
PubMed1996

Interleukin-11 prevents apoptosis and accelerates recovery of small intestinal mucosa in mice treated with combined chemotherapy and radiation.

Previous studies have shown that acute injury to rodent small intestinal mucosa as a result of either chemotherapy or radiation is caused by a combination of high-frequency cell death caused by apoptosis, continued migration of epithelial cells from the intestinal crypts toward the villi, and absence of adequate compensatory mitotic activity in the crypt bases. Recently, we have shown that IL-11, a novel multifunctional bone marrow stromal-derived growth factor, could stimulate rapid repair of small intestinal villous structures in mice treated with combined radiation and chemotherapy by increasing the mitotic index of crypt cells. To further clarify the biological mechanism responsible for its protective action, we used a similar experimental model to evaluate whether IL-11 could reduce the high frequency of apoptosis observed after cytoablative treatment. In the present study, 78 C3H/HeJ mice received 5-fluorouracil at 150 mg/kg body weight intraperitoneal injection 3 days before 7.0-Gy total body irradiation. The animals received IL-11 250 microg/kg body weight/day divided into two equal doses or vehicle control by subcutaneous injections beginning on the same day of irradiation within 1 hour of the end of the dose. The mice killed on Days 1, 2, and 5 after cytoablative treatment were autopsied, the small intestine was processed for histologic examination, and the mitotic index and other parameters were measured, including the expression of the proliferating cell nuclear antigen and of the p53 protein. Apoptosis was detected by a nonisotopic in situ DNA end-labeling technique applied to the same histologic sections. The cytoablative treatment caused marked degenerative changes in the small intestinal mucosa, including shortening of the villi and damage to the crypt cells. The degenerative changes, which included nuclear fragmentation with formation of apoptotic bodies, increased expression of proliferating cell nuclear antigen, and strong expression of p53 was seen in mice killed on Days 1 and 2 after cytotoxic treatment. IL-11 administration resulted in a partial suppression of apoptosis, as shown by a reduced number of crypt cells stained with in situ DNA end-labeling for fragmented DNA. In addition, IL-11 treatment was associated with an increase in the frequency of mitosis and proliferating cell nuclear antigen expression in crypt cells as compared with the vehicle treated mice. Morphometric analysis of intestinal villi and crypt depth showed increased villus length and decreased crypt to villus ratio after IL-11 treatment. These results indicate that IL-11 can exert a potent effect on the recovery of the small intestinal mucosa of mice by its combined effects on proliferation and apoptosis of crypt cells. IL-11 may thus have potential clinical applications in limiting the intestinal toxicity that is associated with cytotoxic therapies.

Animals↗
PubMed1996

Detection of PML-RAR alpha in patients with APL during follow-up period.

OBJECTIVE: To evaluate the significance of PML-RAR alpha transcripts in patients with acute promyelocytic leukemia (APL) during remission period and to follow up the patients through monitoring aberrant gene expression. PATIENTS AND METHODS: This study included 17 patients with APL (5 females and 12 males). Another 19 APL patients during relapse served as control. RNA extraction was obtained through the single-step method. By means of reverse transcriptase polymerase chain reaction (PCR), the PML-RAR alpha was detected in the sample mRNA. RESULTS: Nine out of 10 patients with complete remission (CR) duration shorter than 3 years were positive. Four cases became negative and three remained positive among 7 cases in a long remission of over 3 years. The difference of the positive rate of PML-RAR alpha transcripts between the 2 groups was significant (P < 0.05). Four among 12 positive cases relapsed. No evidence of relapse was present in the 5 negative patients after 9.6 +/- 3.9-month follow-up. Further treatment was therefore given to the 4 positive patients whose treatment was already ceased at that time. By this management they were all in CR during the following 10-month observation. CONCLUSIONS: RT-PCR detection for PML-RAR alpha transcripts was useful in monitoring MRD and guiding further treatment to obtain a long remission. Persistently positive transcripts were closely associated with the relapse.

Adolescent↗
PubMed1996

[The influence of infected mothers on their children's immune response to filariasis].

OBJECTIVES: To investigate the reason for broad clinical spectrum of filariasis among the people in the endemic area, and to know the effect of infected mothers on their children's immune response to filariasis. METHODS: We measured the specific IgG and IgM antibodies in the sera of women and their 1-10 year old children, and maternal and umbilical cord, including Mf cases and control subjects by using IEST. RESULTS: The positive rates of IgG in the sera of women with Mf and their children were 91.4% (53/58) and 65.5% (38/58), and those of the control group 28.6% (34/119) and 24.4% (29/119). The positive rates of IgM were 81.0% (47/58) and 20.7% (12/58), and those the control group 11.8% (14/119) and 10.9% (13/119), respectively. Also, the positive rates of IgG in the sera of women with Mf and their infants were 91.7% (22/24) and 75.0% (18/24), and those of the control group 20.2% (19/94) and 16.0% (15/94). The positive rates of IgM were 70.8% (17/24) and 8.3% (2/24), and those of the control group 10.6% (10/94) and 3.2% (3/94), respectively. CONCLUSIONS: Whether the mother infected with the disease or not, the acquired immunological tolerance and resistance to the disease in their children might not be affected.

Adult↗
PubMed1996

13C-methacetin breath test parameter S for liver diseases diagnosis.

The mechanism of 13C-methacetin breath test is set forth clearly with the analysis of pharmacokinetics mode, and the measuring method of 13C-methacetin breath test and its clinical applications in the diagnosis of liver diseases are reported in detail. On the basis of comprehensive analysis of the clinical test data, the advanced diagnostic parameter S is of important significance for the application and development of breath test.

Acetamides↗
PubMed1996

[Molecular and cellular mechanisms of arteriosclerosis and restenosis: possibilities of gene therapy].

Atherosclerosis and its consequences account for most of morbidity and mortality in Western countries. Atherosclerosis develops over a period of decades and has a complex pathogenesis. It is a disease of the intima and primarily involves four cell types, i.e., endothelial and vascular smooth muscle cells, monocytes and platelets. In recent years, knowledge on the cellular and molecular mechanisms of these cells and their alterations by cardiovascular risk factors and in atherosclerosis has greatly expanded. In particular, it became clear that endothelial cells play a crucial role in the regulation of platelet function, coagulation as well as vascular tone and structure. Interestingly, endothelial dysfunction occurs early, particularly if cardiovascular risk factors such as hyperlipidemia, hypertension and diabetes are present. This could lead to adhesion of circulating platelets and monocytes and increased accumulation of lipids in the subintima as well as increased contraction, migration and proliferation of vascular smooth muscle cells. The fact that atherosclerosis develops only in certain, but not in other parts of the circulation, however, has rarely been considered. With the development of molecular biology techniques it became possible to clone differentially expressed genes in vessels with or without atherosclerosis; this in turn allows to better characterize the molecular and cellular mechanisms of the disease. The search for such candidate genes could set the basis for future genetic interventions. This therapeutic approach is likely to reach clinical importance particularly in monogenetic diseases (i.e., familial hypercholesterinemia), while its use in complex polygenetic diseases such as atherosclerosis is more difficult. Restenosis, however, may be accessible to gene therapy earlier on as it is amenable to local gene transfection.

Arteriosclerosis↗
PubMed1996

17 beta-estradiol inhibits proliferation and migration of human vascular smooth muscle cells: similar effects in cells from postmenopausal females and in males.

OBJECTIVES: Cardiovascular disease is rare in premenopausal women, but increases after the menopause when hormone replacement therapy reduces coronary events. Vascular smooth muscle cell (SMC) proliferation and migration occur in atherosclerosis, restenosis and venous graft disease. We studied the effects of 17 beta-estradiol on SMC proliferation and migration. METHODS: SMC were cultured from saphenous veins of postmenopausal women and age-matched men. Cell growth was determined by 3H-thymidine incorporation and cell counting. Migration of SMC was assessed in 4-well chambers. SMC were seeded in one corner and PDGF-BB in filter paper glued onto the opposite wall. RESULTS: PDGF-BB (5 ng/ml for 24 h) similarly stimulated 3H-thymidine incorporation in female (511 +/- 57%; n = 8) and male (528 +/- 62%; n = 12) SMC. This was reduced by 17 beta-estradiol (10(-8)-10(-6) M; female 313 +/- 52%; male 337 +/- 54%; P < 0.05). PDGF-BB increased the number of SMC (P < 0.0001 at 10 days) obtained from females (153 +/- 3%; n = 5) and males (150 +/- 4%; n = 5), which was inhibited by 17 beta-estradiol (10(-6) M; female 134 +/- 7%; male 128 +/- 5%; P < 0.05). Similar results were obtained with basic fibroblast growth factor. In contrast to 17 beta-estradiol, another steroid (dexamethasone) had no effects on 3H-thymidine incorporation in these cells stimulated with PDGF-BB, PDGF-BB (0.01-1 ng) stimulated SMC migration (P < 0.05) which was inhibited by 17 beta-estradiol (10(-10)-10(-6) M; n = 5; P < 0.005). CONCLUSION: 17 beta-Estradiol inhibits growth-factor-induced SMC proliferation and migration regardless of gender. These effects of 17 beta-estradiol may contribute to its cardiovascular protective properties in postmenopausal women during replacement therapy.

Aged↗
PubMed1996

Amplification, cloning, and sequence comparison of the growth hormone gene for carp (Cyprinus carpio) by the polymerase chain reaction.

Total RNA was isolated from carp pituitary gland. The first strand cDNA was synthesized using oligo(dT) 12-18 as a primer, the total RNA as a template, and AMV reverse transcriptase. Next the polymerase chain reaction (PCR) was performed using the first strand cDNA as a template, the synthetic 29 oligonucleotides as primer and Taq DNA polymerase (94 degrees C, 60 s; 55 degrees C, 30 s; 72 degrees C, 50 s; 35 cycles). After PCR amplification, the products were cloned into an E. coli expression vector (PBluescript II KS+/-). The result of the sequence analysis and the restriction map shows that an open reading frame of the carp growth hormone gene contains 630 base pairs which code for a polypeptide of 210 amino acids including 22 amino acids of the signal peptide and 188 amino acids of the nature growth hormone. Nucleotide sequence and amino acid sequence of our carp growth hormone gene are the same as Koren's carp GH cDNA in the coded region. Compared with Chao's carp GH cDNA, the homology of nucleotide sequence and amino acid sequence for our carp growth hormone gene is 95.6% and 96.7%, respectively, in the coded region.

Amino Acid Sequence↗
PubMed1996

Presence of free radicals in pigment gallstone in vivo.

OBJECTIVE: To clarify whether free radical, which may play a role in pigment gallstone formation, is present in pigment gallstones in vivo. MATERIALS AND METHODS: Free radical signal of gallstones from 18 patients was detected by electron paramagnetic resonance spectroscopy at 77K under anaerobic condition and in air (control). As soon as the anaerobic determination was finished, the fresh anaerobic sample was exposed to air and stored in a freezer at -20 degrees C. RESULTS: Free radical signal (g = 2.0038) was detected in fresh anaerobic samples containing more than 2% bilirubin compound, and the signal intensity correlated linearly with the content of calcium bilirubinate (r = +0.95, P < 0.0005). During the storage at -20 degrees C and exposure to air, the signal intensity of each anaerobic sample and its control increased gradually, eventually reaching the same stable level. Fe(III) signal intensity was enhanced synchronously and related linearly with free radical signal (r = +0.99, P < 0.0005). CONCLUSIONS: Free radical exists originally in pigment gallstones in vivo, and it may play an important role in pigment gallstone formation. The free radical signal carried by gallstones may be strengthened by the action of oxygen in air on bilirubin. The transition metal ions probably take part in the formation of bilirubin free radical.

Bilirubin↗
PubMed1996

[Congenital anotia with hemifacial atrophy (a report of 12 cases)].

Twelve cases of congenital anotia with hemifacial atrophy were examined and analyzed with electromyogram and roentgenography. The results revealed that the development of the deformed side of the face was 30% less than the other side. Because both the soft tissue and the skeleton of the deformed side are undeveloped, they should be dealt with simultaneously.

Abnormalities, Multiple↗
PubMed1996

A study of time window for oxidative stress associated with myocardial ischemia and reperfusion.

OBJECTIVE: To investigate the time window for oxidative stress occurred in myocardial tissue and associated with reperfusion. METHODS: Thirty nine conscious rabbits were subjected to 0.5 hours (h) of myocardial ischemia and reperfusion for 0 h, 6 h, 24 h and 72 h, respectively, and nine rabbits served as controls. Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and myeloperoxidase (MPO), and contents of GSH and malondyaldehyde (MDA) were measured in myocardial tissues taken from ischemic non-necrotic area (INNA), ischemic necrotic area (INA) and non-ischemic area (NIA), respectively. RESULTS: The antioxidant status of INNA was weakened at 6th h, 24th h, and 48th h of reperfusion. Activities of Mn-SOD and Cu-Zu-SOD returned to normal value at 72nd h of reperfusion, but GSH-px activity and GSH content remained in lower value. MDA content had a marked increase at 6th h, 24th h, 48th/h and 72nd h of reperfusion. MPO activity had a progressive increase after reperfusion, with its peak value at 48th h, and PMN accumulation occurred mostly in necrotic zone and its outer board zone. A mild oxidative stress also occurred in non-ischemic tissue, but without obvious neutrophils infiltration. CONCLUSIONS: The time window for oxidative stress associated with myocardial ischemia and reperfusion lasts for at least 72 h, and PMN infiltration is one of the most important factors of delayed myocardial reperfusion injury.

Animals↗
PubMed1996

[Granulocyte-macrophage colony-stimulating factor (GM-CSF), preclinical and phase I clinical investigations].

OBJECTIVE: To conduct preclinical studies and phase I trial of the recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). METHODS: Pharmacodynamics, pharmacokinetic and toxicology of the rhGM-CSF were studied in animal models, and the safety was also evaluated in humans. RESULTS: The human bone marrow cells could be stimulated by purified rhGM-CSF to form multilineage colonies (CFU-GM and BFU-E). The rhGM-CSF administered for 7 days to Beagle dogs and monkeys subjected to 60Co r-ray irradiation was shown to induce both rapid and sustained increase in circulating leukocyte counts. Toxicology testing showed that the LD50 (i.v) was over 5000 micrograms/kg, and LD50 (i.p) over 10000 micrograms/kg in mice. Administration of the rhGM-CSF in excess of four times as much as clinical dosages was not associated with severe chronic toxicities. Most injected rhGM-CSF was excreted from urine, and did not accumulate in the body. In the phase I clinical trial, injecting 2.5-7.5 micrograms/day of rhGM-CSF was safe. CONCLUSION: It is effective and safe to use rhGM-CSF in the treatment of leukocytopenia.

Adolescent↗
PubMed1996

[A pathologic study of delayed myocardial reperfusion injury].

This study was designed to investigate whether a new irreversible injury to the myocardium can occur 6 hours after reperfusion following ischemia. Conscious rabbits were subjected to myocardial ischemia for 30 minutes, followed by reperfusion. Horseradish peroxidase (HPR) tracing with TTC staining and histological quantification were used to study the histopathological changes in myocardial tissues. Necrotic myocardium at 6 hours after reperfusion gave positive HRP results and viable myocardium at 24 hours after reperfusion gave positive TTC results. Some myocardial tissue between the above two regions were found to be HRP negative as well as TTC negative, indicating that myocardial tissue death occurred between 6 to 24 hours after reperfusion. The myocardial infarct size at 24, 48, and 72 hours after reperfusion were 7.0%, 5.1% and 3.2% larger than that 6, 24 and 48 hours respectively. Therefore, new irreversible myocardial injury in the rabbit can still occur after 6 hours of reperfusion following myocardial ischemia for 30 minutes and cumulative myocardial injury from 6 to 72 hours after reperfusion can result in a marked extension of the size of myocardial infarct.

Animals↗
PubMed1996

[Radiation therapy of esophageal carcinoma: a report on 180 cases].

One hundred eighty patients with pathologically proved esophageal carcinoma accepted for surgery, for various resons, were given radical radiation therapy. The length of the lesions ranged from 2 to 9 cm. They were treated either by the isocenter technique alone or A-P plus isocenter irradiation to a total dose of 50-70 Gy/5-7 wk. The 1-, 3- and 5-year survival rate was 64.4%, 34.4% and 23.3%, respectively. The 3- and 5-year survival rates showed that lesions in the upper third responded to radiotherapy better than did those in the middle and lower thirds (P < 0.05). The 5-year survival of patients with upper third lesions treated with radiation alone (44.5%) was slightly better than that of surgery. The result of lesions in the middle third was slightly inferior, and that of lower third was even more inferior to that of surgery. The result of radiation alone for operable esophageal carcinoma was comparable to that of surgery.

Adult↗