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Biomedical subjects

Y Z Zhou

Publications and source records attributed to Y Z Zhou.

At least 19 recordsLinked to original sources
PubMed2004

FePt-Ag nanocomposite thin films with longitudinal magnetic anisotropy.

A well-controlled method to fabricate FePt thin films with the (200) texture and longitudinal magnetic anisotropy for high-density magnetic recording media is reported. FePt-Ag nanocomposite thin films with L1(0) ordered FePt grains embedded in an Ag matrix were deposited on the Cr90Ru10/glass by co-sputtering from Ag and FePt targets. The Ag doping suppressed the (001) texture but improved the L1(0) FePt (200) texture. The magnetic easy axis of FePt-Ag thin films changed from perpendicular to longitudinal in direction. In-plane coercivity of the films varied from 0.8 kOe to 6.5 kOe, depending on Ag contents in the films and under-layer thickness. The change from the (001) to (200) texture could be due to the competition of grain-boundary energy and epitaxial-strain energy.

Anisotropy↗
PubMed2003

Evolution of microstructures in materials induced by electropulsing.

Nanostructures were formed in several conventional materials under single electropulsing, that is nanophases of alpha-Cu(Zn) and beta'-(CuZn) in a cold-worked alpha-Cu(Zn) alloy, nanosized gamma-Fe in a low-carbon steel, nanosized alpha-Al in a superduralumin, and orientated nanosized TiC in a TiC/NiCr cermet. The mechanisms responsible for the above nanostructured transitions can be attributed to the competition of many factors induced by electropulsing, including high-rate heating, thermal stress, reduced thermodynamic energy barrier and high-rate electron impacting. Also, many low-energy dislocation configurations, twins and stacking faults were formed in the copper alloy and cermet under the electropulsing. Such evolution of defects was associated with the electrical, thermal and stress energies induced by the electropulsing.

Journal Article↗
PubMed2001

[Features of breast ultrasound image and its correlation with estradiol and progesterone level in different phases of menstrual cycle in normal women].

OBJECTIVE: To determine the features of the breast ultrasound image and its correlation with estrogen and progestogen level during different phases of menstrual cycle in normal women. METHODS: Breast ultrasound was performed during luteal phase and late follicular phase in 50 women aged 25-45, with normal menstrual cycle and no distinct breast disease. Breast section thickness, ductal width, breast structure and blood flow were measured. Initial time and persistent days of the cyclic breast pain were recorded. Serum estradiol (E2) and progesterone (P) levels were measured by enzyme immunoassay on the day of ultrasound performed. RESULTS: Breast glandular section was thicker (increasing by 7.3%) in luteal phase than that in late follicular phase and breast ductal was wider (increasing by 13%) in late follicular phase than that in luteal phase. However, both of them had no significant difference. Thirty women (60%) experienced cyclic premenstrual mastalgia, lasting 4 days. Twenty four women (48%) had breast structure changes, nineteen (63.3%) of 30 women with cyclic mastalgia, but only 5 (25%) of 20 women without breast pain had breast structure change (chi 2, P < 0.01). Average serum E2 level of women with or without cyclic breast pain in luteal phase were 365.0 pmol/L and 335.3 pmol/L respectively (P > 0.05), serum progesterone level were 73.3 nmol/L and 66.1 nmol/L respectively (P > 0.05). Serum E2 levels of women with or without cyclic breast pain in late follicular phase were 299.9 pmol/L and 385.8 pmol/L respectively (P = 0.05). Average serum E2 levels of women with or without breast structure change in luteal phase were 368.1 pmol/L and 322.7 pmol/L respectively (P < 0.05). Serum P levels were 78.8 nmol/L and 62.2 nmol/L respectively (P = 0.05); Estradiol levels in late follicular phase were 301.9 pmol/L and 364.2 pmol/L respectively (P > 0.05). CONCLUSIONS: Image of breast ultrasound changed following menstrual cycle in normal menstrual women. Breast structure changes is related to breast pain. Breast pain and breast structure changes may be caused by higher E2 and P level in luteal phase and lower E2/P ratio in late follicular phase.

Adult↗
PubMed2001

[Advances in genetic epidemiology].

We have discussed some advances in genetic epidemiology, which include the effect of gene-environment interaction on diseases. The developing genetic tests and genetic information will benefit the health care and disease prevention.

Genetic Counseling↗
PubMed2000

[Selectivity of poly (4-methyl-5-vinylthiazole) stationary phase in reversed-phase liquid chromatography].

In this paper, the selectivity of poly(4-methyl-5-vinylthiazole) stationary phase (PMV CA phase) is comprehensively studied in reversed-phase liquid chromatography (RPLC) mode with methanol-water system. The selectivity difference between PMV CA phase and three commonly used RPLC stationary phases (C18, C8 and Phenyl phase) is shown. Four typical species of standards (alkylbenzens, chlorobenzenes, nitrobenzenes and PAHs) are selected for the selectivity study. It is shown that the PMV CA phase has some special selectivities: 1) It has different selectivity from C18 and C8 phase because the PMV CA phase may form diploe interaction, pi-electron interaction and hydrogen bonding interaction (with the nitrogen atom and oxygen atom on the phase) with solutes owing to its polar aromatic thiazole ring and polar ester bond etc. on the phase; 2) It has similar property as phenyl phase because both of them can form pi-electron interaction with solutes. But owing to its polar thiazole ring and other polar group on the phase, which may form dipole interaction and hydrogen bonding interaction with solutes, there are still some differences between these two phases.

Benzo(a)pyrene↗
PubMed1999

99mTc-MIBI single-photon emission-computed tomography in diagnosis of lung cancer and mediastinal metastasis lymph nodes.

AIM: To evaluate the value of technetium-99m-methoxyisobutyl isonitrile (99mTc-MIBI) single-photon emission-computed tomography (SPECT) in diagnosis of lung cancer and in preoperative prediction of mediastinal metastasis lymph nodes. METHODS: After the chest image of 99mTc-MIBI SPECT, fifty patients (40M, 10F; age 56 a +/- 11 a) diagnosed "lung field shadow" underwent the lung focus and mediastinal lymph nodes resection. As the golden standard, pathologic diagnosis was used to evaluate the role of preoperative 99mTc-MIBI SPECT. RESULTS: The sensitivity, specificity, and accuracy of 99mTc-MIBI SPECT were 93%, 50%, and 86%, respectively in lung cancer and 81%, 95%, and 88%, respectively in mediastinal metastasis lymph node. The results were also better than those of chest scan with CT. CONCLUSION: The 99mTc-MIBI SPECT is a useful and noninvasive method for diagnosing lung cancer and predicting mediastinal metastasis lymph nodes, which will guide the surgeon to resect the mediastinal metastasis lymph nodes.

Adult↗
PubMed1998

Cryopreservation and transplantation of dog trachea.

In order to meet the need of trachea transplantation for clinical application, it is important to research the methods of cryopreservation and transplantation of trachea. By the thermal analyses and thermal control techniques, combined with electron microscopy, the effects of cooling and warming rates with different concentrations of cryoprotective agents were studied. Also the transplantation technique was studied, eighty five percent (17/20) of the dogs were survival after the transplantation with cryopreserved tracheas.

Animals↗
PubMed1996

Frequent loss of chromosome 8p in hepatitis B virus-positive hepatocellular carcinomas from China.

The majority of hepatocellular carcinomas (HCCs) from hepatitis B virus (HBV)-endemic areas contain integrated viral sequences. To better understand the role of HBV DNA insertion in tumorigenesis, we examined the integration site of a HCC harboring a single insert. Cellular DNAs flanking the viral sequences were mapped to chromosomes 17 and 8, indicating a translocation had occurred at the site of viral integration. Regional mapping of chromosome 17 demonstrated that HBV had integrated in 17p12-pter, a region that harbors the p53 tumor suppressor gene. Many studies have shown that chromosome 17p allele loss occurs frequently in HCCs from certain geographical areas. To investigate the chromosome 8 allele status in Chinese HCCs, a panel of 37 matched normal and HCC DNAs from Qidong, China was analyzed for tumor-specific allele loss with RFLP probes from both arms of chromosome 8. Tumor-specific loss of heterozygosity was highest on the short arm with 71.4% (10/14) and 85.0% (17/20) of the informative patients missing an allele for 8p23 (YNM3) or 8p21 (NEFL), respectively. Allele loss from the long arm of chromosome 8 was also observed with 30.0% (6/20) and 33.3% (7/21) of the samples informative for 8q22 (CA2) and 8q24 (MCT128.2), respectively. The high allele loss on 8p correlates with recent studies of other human cancers and is interpreted to indicate that a tumor suppressor gene(s) whose loss is important for carcinogenesis lies within this region. These findings also support a model in which HBV insertions associated with gross chromosomal changes can identify genomic regions where alteration is important for development of some HCCs.

Carcinoma, Hepatocellular↗
PubMed1995

[Regulatory role of galanin on prolactin and beta-endorphin release from anterior pituitary lobe of rat].

The role of brain-gut peptide galanin in the regulation of prolactin (PRL) and beta-endorphin (beta-EP) release from anterior pituitary lobe was studied in vivo in conscious male rats and in vitro with cultured anterior pituitary cells of the rat. Galanin (1 microgram or 3 micrograms/rat) injected into the third cerebral ventricle of rats produced highly significant, dose-related increases of PRL resting secretion, but did not alter resting secretion of beta-EP and restraint stress-induced release of PRL and beta-EP. However, galanin (0.05, 0.5 and 1.0 micrograms/5 x 10(5) cells.ml-1) induced highly significant, dose-related increase of beta-EP secretion from dispersed anterior pituitary cells, but failed to alter significantly PRL secretion from the cultured cells. These results indicate that central galanin has a stimulatory role in pituitary PRL resting secretion via the hypothalamus, whereas peripheral galanin stimulates beta-EP secretion only via direct action of this peptide in anterior pituitary cells.

Animals↗
PubMed1994

[Cardiac arrhythmia after lung cancer surgery--an analysis of 140 pneumonectomy cases].

Among 808 surgically resected lung cancer cases at Shanghai Chest Hospital during the period of January 1991 to December 1992, 140 of them (17.3%) underwent pneumonectomy (47 right, 93 left). In the 140 cases: 124 male, 16 female; aged 27-74 yrs, pre-operative abnormal EKG was found in 38 cases. Postoperatively, arrhythmia occurred in 76 cases, with an incidence of 54.3%. Of the 76 arrhythmias, atrial fibrillation was seen in 7 patients, atrial premature beats in 2, supraventricular tachycardia in 1 and sinus tachycardia in 66. The results indicate that cardiac arrhythmia is a common complication after pneumonectomy for lung cancer surgery. The major causes of arrhythmia were incisional pain, hypovolemia due to blood loss and respiratory insufficiency due to anoxia. The perioperative measures to prevent arrhythmia were discussed.

Adenocarcinoma↗
PubMed1994

[Management of the A-pattern deviation with overacting superior oblique muscle].

The overacting superior oblique muscle is usually associated with A-pattern ocular deviation. 10 such cases (14 eyes), 9 exotropic and 1 esotropic, were performed superior oblique tenotomy with horizontal and vertical corrective surgery; they all attained postoperative normal ocular alignment in the primary position. The A-pattern deviation was corrected and overaction of the superior oblique improved. The authors point out that in the absence of binocular vision and abnormal retinal correspondence, superior oblique tenotomy is a safe and useful procedure for patients with 20 delta and over of A-pattern deviation.

Adolescent↗
PubMed1993

Deletion of the E-cadherin gene in hepatitis B virus-positive Chinese hepatocellular carcinomas.

Frequent allele loss from chromosome 16q was recently described for human tumors of the breast, prostate gland and liver, indicating the possible presence of a tumor-suppressor gene on that chromosome arm. In this study, the chromosome 16 allele status of 38 hepatocellular carcinomas in Chinese patients was determined with restriction-fragment-length polymorphism analysis. Tumor-specific allele loss was detected in 14 (74%) of 19 patients informative for 16p markers and in 22 (85%) of 26 patients informative for 16q markers. Quantitative densitometric analysis revealed reduction to hemizygosity of the E-cadherin cell adhesion gene (localized to 16q22.1) in 18 (64%) of the 28 patients for whom quantitative data were available. Reduced expression of E-cadherin has been associated with invasion and metastasis in several human cell lines and primary tumors, and our results suggest that one mechanism of reduced E-cadherin expression is the loss of one copy of the E-cadherin gene.

Adult↗
PubMed1993

[Pancreatic polypeptide in the control of beta-endorphin and prolactin release from rat anterior pituitary in vivo and in vitro].

This study was designed to examine the possible effects of pancreatic polypeptide (PP) on beta-endorphin (beta-EP) and prolactin (PRL) release from rat anterior pituitary in vivo and in vitro. Injection of 0.5 microgram or 2.0 micrograms PP into the third ventricle of the brain (3rd v.i.) produced a significant decrease of the beta-EP and PRL resting secretion. 0.5 microgram PP (3rd v.i.) did not affect restraint stress-induced release of beta-EP, but partially lowered stress induced release of PRL. 2.0 micrograms PP (3rd v.i.) partially reduced restraint stress-induced release of beta-EP and completely suppressed stress-induced release of PRL. In order to investigate a possible direct action of PP on beta-EP and PRL secretion from the anterior pituitary gland, we incubated dispersed anterior pituitary cells with synthetic PP (0.05, 0.625 and 1.00 micrograms) for 1 n, the secretion of beta-EP was not affected at any dosage tested, but 0.625 and 1.00 micrograms PP significantly decreased the PRL secretion. These data indicate that PP may have an inhibitory role in the control of beta-EP secretion at the level of the hypothalamus, and an inhibitory role in the control of PRL secretion at the level of either hypothalamus or anterior pituitary.

Animals↗
PubMed1992

p53 mutations cluster at codon 249 in hepatitis B virus-positive hepatocellular carcinomas from China.

DNA samples from 36 hepatocellular carcinoma (HCC) patients from China were screened for a specific mutation affecting codon 249 of the p53 gene, recently identified as a hotspot mutation in some HCCs. We detected the tumor-specific p53 codon 249 mutation in 21 (58%) of 36 HCCs examined. Thirteen patients with the specific codon 249 mutation had lost the remaining allele of p53, whereas the remaining eight patients appeared to have retained both copies of the gene. These results suggest that alterations of p53 may be important events in the genesis of HCCs and that point mutation may precede allele loss.

Adult↗
PubMed1991

Hepatitis B virus integration event in human chromosome 17p near the p53 gene identifies the region of the chromosome commonly deleted in virus-positive hepatocellular carcinomas.

The development of hepatocellular carcinoma (HCC) presumably occurs in multiple steps and is influenced by numerous factors. Hepatitis B virus (HBV) is strongly associated with the development of HCC in people chronically infected with the virus, but the mechanism of viral involvement remains unclear. One possibility is that the gross chromosomal alterations frequently observed in HCC DNA at the site of HBV integration may alter the expression of important nearby cellular genes. We previously reported the cloning and characterization of a HBV insert from a Chinese HCC. The viral insert mapped to chromosome 17p11.2-12, and cellular sequences were duplicated at the site of viral integration. In the present study a DNA probe derived from cellular DNA sequences adjacent to the previously characterized HBV insert was used to analyze a set of 19 matched normal liver and HBV-positive hepatoma samples obtained from the same region of China, near Shanghai. Tumor-specific DNA changes were detected in two additional HCCs, suggesting that the small region of chromosome 17p defined by the flanking cell DNA probe is commonly altered in hepatomas. Restriction fragment length polymorphism studies demonstrated that the loss of one copy of portions of chromosome 17 occurred in 10 (53%) of the 19 patients. The loss of one allele of the p53 gene (located on chromosome 17p13) occurred in at least 6 (60%) of the 10 patients who were heterozygous at the p53 locus. As the p53 gene is known to possess tumor suppressor activity, the functional loss of this gene may be a significant step in the development of a subset of HCCs. High levels of allele loss also were detected for chromosomes 8q (4 of 9; 44%) and 16p (5 of 6; 83%) and may indicate the presence of additional cellular genes whose functional loss is important in the development of HCCs.

Carcinoma, Hepatocellular↗
PubMed1990

[Surgical treatment of partial atrioventricular canal malformations].

27 cases of partial atrioventricular canal malformations were treated surgically, without operative death or serious complications. There were 15 males and 12 females, aged from 6 to 32 years (mean 14.7 years). Diagnosis was confirmed by echocardiography in all cases and catheterization in 13 as well. Surgical correction was performed under CPB combined with moderate hypothermia. Right atrium approach was used. The anterior mitral cleft was sewn with interrupted sutures and annuloplasty is done when regurgitation is obvious. Atrial septal defect was repaired with patch.

Adolescent↗
PubMed1990

[Diagnosis and treatment of inferior oblique muscle paresis].

The authors report 12 cases of isolated inferior oblique muscle paresis which is very uncommon and mostly of congenital origin, though trauma is also cause. The clinical features, differential diagnosis and treatment of the disease are discussed. Inferior oblique palsy is differentiated from contralateral inferior rectus palsy by Park's 3-step test, and from Brown's syndrome by forced duction test and the overaction of the antagonist superior oblique during version. Surgical procedures include shortening and advancement of the inferior oblique muscle, recession of the contralateral superior rectus and shortening of the contralateral inferior rectus muscle, and tenotomy of the ipsilateral superior oblique.

Adolescent↗