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Biomedical subjects

Y Yan

Publications and source records attributed to Y Yan.

At least 253 records · Page 14Linked to original sources
PubMed1997

[Antagonistic effect of calcitonin gene related peptide on arrhythmia in rats].

Premature ventricular contraction (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF) were developed by endothelin-1 (ET-1) injected into the coronary ostia at the dose of 900 pmol/kg in anesthetized rats. No arrhythmia was elicited but blood pressure fell temporarily by calcitonin gene related peptide (CGRP), the injection into the coronary ostia. After pretreatment with CGRP incidence and severity of arrhythmia decreased at the same ET-1 dose. Arrhythmia score in CGRP 1200 pmol/kg + ET-1 group was lower than that in ET-1 group (P < 0.01). The results revealed that antiarrhythmic effect of CGRP may be partially brought about by its antagonistic effect against ET-1 induced arrhythmia.

Animals↗
PubMed1997

[Applied anatomy of the vessels in the dorsum of the finger].

Twenty adult cadavers were used to study the vessels of the flag flap in the dorsum of the finger with careful dissection and measurement. The results indicate: 1. The main blood supply to the dorsum of the finger comes from the cutaneous branches of the proper palmar digital artery. The dorsal digital artery is short and small, taking part in the blood supply of the dorsal digital skin of the proximal phalanges. 2. The veins communicate with each other, forming the first, the second and the third venous arch at the level of the distal phalangeal joint, the proximal phalangeal joint and the middle of the proximal phalanges. 3. The third venous arch is big. Proximally, the veins grouped to form radial and ulnar trunks, which communicate with the dorsum veins. 4. There are almost no veins in the area between the radial and ulnar venous trunk, which might be called the "vein lacking area." 5. The venous trunk, radial or ulnar, locates 4.1 +/- 0.1 mm from the midline of the finger dorsum at the middle of the proximal phalanges, and 5.2 +/- 0.2 mm at the metacarpophalangeal joint. Based on the results, we described the anatomical characteristics, the principle of design and the survival mechanism of the flag flap.

Adult↗
PubMed1997

[Applied anatomy of the submental vessels and submental flaps].

To search ideal flaps for facial defect repair, the authors performed dissection in the submental region of 20 cadavers. Different methods were used in the anatomic study. It is concluded that 1. there is a submental artery and two concomitant veins on each side of the submental region; 2. four types of flaps can be formed; 3. the flap can be transferred as a free or pedicled flap; 4. while creating the flap, the anterior belly of the bigastric muscle should be included and the branches of the facial nerve and inferior alveolar nerve must be protected. With the well-matched color and texture, the flap of the submental region is suitable for facial defect repair.

Arteries↗
PubMed1997

[Effects of locally used SD zinc, SD silver and skin transplantation on the combined radiation-burn injury in the rat].

Effects of local use of sulfadiazine (SD) zinc, SD silver in the wound and skin transplantation on the combined injury of 6 Gy radiation and 15% TBSA burn were investigated in the present study. In the three groups of SD zinc or SD silver plus skin grafting at 15 d after combined injury and SD zinc alone, the 15-day survival rates were 63%, 69% and 75% respectively, and significantly higher than that of control group (42%). The repair time of burn wound was shorter and the number of white blood cells was lower than that of control. Animals in the group of local use of SD silver followed by skin grafting on the 7th day all died, but all of the animals survived when the skin grafting was performed after 15 days. These results suggested that SD zinc and SD silver showed some therapeutic effects on the combined radiation-burn injury. In critical phase of the combined injury, surgical operation should be prohibited. However, in the recovery phase, skin transplantation could be performed.

Administration, Topical↗
PubMed1997

[Assay of terpenes in the leaves of Ginkgo biloba extract and its preparations by in situ fluorometric TLC].

A new TLC method for the assay of terpene lactones in Ginkgo biloba extract and its preparations has been established by means of optimized development condition and post-chromatographic thermal fluorescence derivatization. Satisfactory results can be obtained through polynomial regression calibration. The data obtained by this method have been proved ten times higher in sensitivity than those obtained by HPLC-refracto-detector.

Chromatography, High Pressure Liquid↗
PubMed1997

[Chest CT and its assessment of resectability in lung cancer].

OBJECTIVE: To evaluate chest CT and its relation to possible surgical resection in lung cancer patients. METHODS: Ninty-five patients who were diagnosed and confirmed as having lung cancers by surgery and pathology were divided into three groups: (1) Radical resection group; (2) Palliative resection group and (3) Thoractomy group. The diameter of the tumor, the proximity to mediastinum and/or the hilum and the invasion of their lymph nodes were measured. Meanwhile, the changes in the mediastinum and thoracic cavity on the chest CT were noted in these three groups. RESULTS: The diameter of the tumor in each group was 4.10 +/- 1.75, 3.90 +/- 1.20, 5.20 +/- 3.66 (cm, mean +/- s, P > 0.05). The proximity to the mediastinum and/or the hilum and the invasion of their lymph nodes was 2.68 +/- 1.60, 4.02 +/- 1.56, 4.85 +/- 3.28 (cm, mean +/- s, P < 0.01, P < 0.05). The characteristic change in the thoractomy group is deformity in the lymph nodes in the mediastinum and hilum. CONCLUSION: There is no obvious relation between the diameter of the lumg tumor and surgical resection, but the proximity to the mediastinum and/or the hilum and the invasion of their lymph nodes is an important factor. It is possible to perform a radical resection when its contact is less than 2.68 +/- 1.60 cm. Obvious deformity of the mediastinal structures and the hilum is a contraindication for lung cancer surgery.

Adenocarcinoma↗
PubMed1997

[Effects of yizhi pills on memory, superoxide dismutase and malondialdehyde of brain and immunity in mice].

Passive avoidance tests have shown that Yizhi Pills (YZ) markedly improve the memory of normal mice at a dose of 100 mg/kg after oral administration for fifteen days, and significantly reverse the scopolamine, NaNO2 and EtOH-induced disruptions of memory retention in mice at doses of 100, 200, 500 mg/kg after oral administration for five days. In aged mice induced by D-galactose, YZ also significantly improve the impaired memory, increase the activity of SOD and decrease the content of MDA in brain. All these effects were observed at doses of 200, 500 mg/kg after oral administration for forty-one days. YZ significantly promote blood carbon particle clearance, enhance hemolysin antibody in immunodepressed mice induced by cyclophosphamide, and increase earswelling in immunodepressed mice induced by prednisolonum.

Animals↗
PubMed1997

[Effect of bone marrow transplantation conditioning regimen on thyroid and adrenocortical functions in patients with blood diseases].

OBJECTIVE: In order to investigate the life quality of patients with hematological diseases after bone marrow transplantation (BMT). METHODS: Pituitary-thyroid and adrenocortical function were de tected in 29 patients with hematological diseases before and after BMT. RESULTS: All patients had normal thyroid and adrenocortical functions before BMT. As compared with pre-BMT,the median serum TSH levels were significantly increased at 3, 6, 12 (P<0.01), 24-60 (P<0.05) months post-BMT. The adrenocortical function had no change in all patients, and thyroid dysfunction were found in 6 of 24 patients detected at a median time of 6 month post-BMT. Five of the 6 thyroid dysfuntion patients developed hypothyroidism, and one hyperthyroidism. CONCLUSION: There was little effect of conditioning regimen on adrenocortical function, while thyroid dysfunction was common after BMT. Long term follow up on thyroid function in patients after BMT is necessary.

Adolescent↗
PubMed1997

[Effects of SAD on cytogenetics of mouse embryonic cells and its embryo development].

We report here that SAD may not only suppress transcription activity of rRNA genes, but also increase SCE frequency of mouse embryonic cells, leading to bloching of the embryo development and fetal death, and finally significant decrease of birth percentage of the new born offsprings. Ata concentration of SAD in 10(-5)mol/L, the transcription activity of rRNA genes was decreased to 15% of the normal level, and the SCE frequency was increased doubly, leading to that the birth percentage was decreased to 50% of normal one. When SAD concentration of 10(-3)mol/L was used the transcription activity of rRNA genes was completely suppressed and SCE frequency was increased to as 4.8 times high as normal, leading to that the birth percentage dropped to 4% from 100%. Our results indicates that both the cytogenetic effects and the inhibition of the embryonic cells are directly proportional to the SAD concentration used. The relationship between the change of both the rRNA gene transcription and SCE frequency and the degree of embryo development are also discussed preliminarily.

Aldehydes↗
PubMed1997

[Comparative study of expression of p21 and c-myc protein in hepatocellular carcinoma with pericarcinomatous liver tissue].

Expression of p21 and c-myc protein in hepatocellular carcinomas and their surrounding liver tissue was detected on serial sections by immunohistochemical method. The results showed that the positive rates of p21 expression were 53.3% (16/30) and 96.7% (29/30) in hepatocellular carcinomas and pericarcinomatous liver tissue, and 40% (12/30) and 86.7% (26/30) and 86.7% (26/30) for c-myc protein expression respectively. Their incidences in pericarcinomatous liver tissue were higher than that in cancer tissue (P < 0.01). The patterns of p21 and c-myc protein in cells were cytoplasm, membrane and/or nuclear types. Their expression was more intensive in pericarcinomatous hepatocytes, especially in liver cirrhosis nodes. The results indicate that abnormal activiation and expression of oncogene ras and c-myc may be related to hepatocellular carcinogenesis.

Adult↗
PubMed1996

Growth pattern and clinical correlation of subcutaneously inoculated human primary acute leukemias in severe combined immunodeficiency mice.

We examined the ability of patient-derived human leukemic blasts to generate leukemic growth and dissemination in severe combined immunodeficiency (SCID) mice by subcutaneous inoculation without conditioning treatment or administration of growth-promoting cytokines. Additionally, we correlated the growth pattern with the clinical outcome of patients from whom the leukemic cells were derived. The leukemias displayed three distinct growth patterns, ie, either aggressive, indolent, or no tumor growth. Leukemic cells from 6 of 13 patients with acute myeloid leukemia (AML), 4 of 7 T-cell acute lymphoblastic leukemia (T-ALL), and 11 of 16 patients with B-lineage ALL grew as subcutaneous tumors, with a significant number subsequently disseminating into distant organs in SCID mice. Patients whose leukemic blasts displayed an aggressive growth and dissemination pattern in SCID mice had a relatively poor clinical outcome, whereas patients with AML and T- or B-lineage ALL whose leukemic blasts grew indolently or whose cells failed to induce growth had a more favorable clinical course. Our study has shown that the subcutaneous inoculation of patient-derived human leukemic cells in SCID mice can engraft and grow as subcutaneous tumors with subsequent dissemination to distant organs in a manner analogous to their pattern of growth in humans. Additionally, these data suggest a clinical correlation to the growth and dissemination of some leukemic subtypes that may represent not only an additional prognosticator for patient outcome, but also a vehicle for the study of the biologic behavior of human leukemias and the development of novel therapeutic strategies.

Acute Disease↗
PubMed1996

A novel HLA class II-independent TCR-mediated T cell activation mechanism is distinguished by the V beta specificity of the proliferating oligoclones and their capacity to generate interleukin-2.

Superantigens can induce proliferative T cell responses after complex formation with major histocompatibility complex (MHC) class II antigens. In this study, highly purified variant T cells from a histocompatibility leukocyte antigen (HLA) (human major histocompatibility complex) class II-deficient patient were stimulated with toxic shock syndrome toxin 1 (TSST-1) in the presence of either HLA class II-negative or normal antigen-presenting cells (APC). The proliferative responses were similar to those of normal T cells even when HLA class II structures were absent on both responding T cells and costimulatory APC. However, the V beta specificity of responding T cells differed depending on the presence or absence of HLA class II antigens on the APC. In the presence of HLA class II-negative costimulatory APC, TSST-1 induced primarily proliferation of V beta 2-expressing T cells, whereas in the presence of normal APC virtually all responding T cells expressed V beta elements different from V beta 2. In addition, in the presence of normal APC, T cells responding to TSST-1 produced much higher amounts of interleukin-2 than T cells proliferating in the presence of HLA class II-negative APC. These findings suggest that T cells bearing selected V beta elements can directly interact with and respond to superantigen without involvement of HLA class II structures. Thus, our findings introduce a novel and distinct T cell receptor-mediated activation mechanism by which specific subpopulations of T cells respond to superantigen in the absence of HLA class II structures on APC.

Antigen-Presenting Cells↗
PubMed1996

Expression of members of the proteolipid protein gene family in the developing murine central nervous system.

Two homologous cDNAs were previously isolated by expression cloning with a monoclonal antibody that recognized a CNS neuronal membrane protein. Both cDNAs, M6a and M6b, bore significant homology with the major myelin proteolipid protein, PLP/DM20. Our initial studies of M6 gene expression in the adult mouse brain showed that M6a was present in neurons, PLP/DM20 in oligodendrocytes, and M6b in both neurons and glia. This led to the recognition of a novel gene family that included the oligodendrocyte-specific PLP/DM20 gene and the neuronal M6 genes. These observations supported the idea that PLP/DM20 may have functions other than myelination. In this report, we describe the spatial and temporal patterns of expression of M6a, M6b, and PLP/DM20 in the developing nervous system. PLP expression was limited to the white matter. M6a appeared in post-mitotic neurons of the brain and spinal cord as early as E10, and later in the hippocampus, cerebral cortex, and the granule cells of the cerebellum. In contrast, M6b was expressed at early embryonic stages in the ventricular zone of the spinal cord, and later during development in both neurons and glia. The early appearance of M6a and M6b mRNAs in the murine CNS suggested that these molecules might play an important role in the development of a variety of neural cell types.

Animals↗
PubMed1996

Chromosomal mapping of the human M6 genes.

M6 is a neuronal membrane glycoprotein that may have an important role in neural development. This molecule was initially defined by a monoclonal antibody that affected the survival of cultured cerebellar neurons and the outgrowth of neurites. The nature of the antigen was discovered by expression cDNA cloning using this monoclonal antibody. Two distinct murine M6 cDNAs (designated M6a and M6b) whose deduced amino acid sequences were remarkably similar to that of the myelin proteolipid protein were previously isolated. We have isolated partial human cDNA and genomic clones encoding M6a and M6b and have characterized them by restriction mapping, Southern hybridization with cDNA probes, and sequence analysis. We have localized these genes within the human genome by FISH (fluorescence in situ hybridization). The human M6a gene is located at 4q34, and the M6b gene is located at Xp22.2. A number of human neurological disorders have been mapped to the Xp22 region, including Aicardi syndrome (MIM 304050), Rett syndrome (MIM 312750), X-linked Charcot-Marie-Tooth neuropathy (MIM 302801), and X-linked mental retardation syndromes (MRX1, MIM 309530). This raises the possibility that a defect in the M6b gene is responsible for one of these neurological disorders.

Amino Acid Sequence↗
PubMed1996

Structure determination of simian virus 40 and murine polyomavirus by a combination of 30-fold and 5-fold electron-density averaging.

BACKGROUND: Simian virus 40 (SV40) and murine polyomavirus (polyoma) are non-enveloped DNA tumor viruses. Their structurally similar capsids, about 500 degrees in diameter, are formed by 72 pentamers of the major coat protein VP1. RESULTS: We describe in this paper the structure determination of SV40 and polyoma at 3.8 degree resolution, focusing particularly on methodological issues, and on a comparison of the overall molecular organization in the two related virus particles. Initial phases for SV40 were obtained by single isomorphous replacement at 6.5 degree. Phases were refined and the resolution extended to 3.8 degree by a combination of strict 5-fold and partial 30-fold electron-density averaging. The structure of polyoma was subsequently determined by systematically translating and rotating the individual VP1 pentamers, in order to find the maximum correlation between calculated and observed structure factors. The resolution was then extended to 3.8 degree, also by phase refinement through electron-density averaging. CONCLUSION: The strategies for density averaging and for molecular replacement, used to determine the SV40 and polyoma structures, are likely to be generally useful. The individual building blocks, the VP1 pentamers, are essentially identical in both cases, as are the local details of their interactions with neighboring pentamers. Nevertheless, the arrangement of the pentamers with respect to each other is somewhat different in the two viruses. Whereas SV40 is almost spherical, with all pentamers at identical radii, the pentamers in polyoma that lie on icosahedral fivefold axes are displaced outward by about 5 degree.

Capsid↗