Biomedical subjects

M He

Publications and source records attributed to M He.

At least 55 records · Page 3Linked to original sources

PubMed2001

[Effect of zinc on the activities of ATPase of erythrocyte membrane].

The effects of zinc on the activities of Na+, K(+)-ATPase and Ca2+, Mg(2+)-ATPase of erythrocyte membrane were studied both in vivo and in vitro. Male adult rats were divided into three groups and fed on diets with different concentration of zinc (2.2, 28 and 128 mg/kg diet). Eight rats of each group were sacrificed after 25 days and the activities of the two ATPase were measured. The rest rats were changed diet for an other seven days to detect the sensitivities of the ATPases. The activities of these ATPase were also determined in fresh human erythrocyte membrane treated with different concentration of zinc (0, 5, 10, 50, 100, 500 mumol/L). The results showed that the activities of both Na+, K(+)-ATPase and Ca2+, Mg(2+)-ATPase were in close relationship with zinc concentration, too low or too high zinc could decrease them. Compared with Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase was more sensitive to zinc deficiency and in a slower reaction to zinc supplement, but it could stand higher zinc concentration. It was concluded that zinc played an important role on maintaining the normal activities of Na+, K(+)-ATPase and Ca2+, Mg(2+)-ATPase.

Animals↗

PubMed2001

Metabolism of sulfinpyrazone sulfide and sulfinpyrazone by human liver microsomes and cDNA-expressed cytochrome P450s.

Human liver microsomes catalyze the oxidation of sulfinpyrazone sulfide (SPZS) to a variable mixture of sulfinpyrazone (SPZ) enantiomers and two minor phenolic metabolites. In one, the thiophenyl ring is hydroxylated, whereas in the second an N-phenyl ring is hydroxylated. SPZ is further oxidized to sulfinpyrazone sulfone (SPZO) and a minor polar metabolite that also has an N-phenyl ring hydroxylated. Determination of the metabolism of SPZ and SPZS under modified incubation conditions of prior heat treatment, higher pH, and the presence of detergent indicated that the formation of SPZ was cytochrome P450 (P450)- but not flavin monooxygenase-dependent. Specific P450 inhibitors (sulfaphenazole, quinidine sulfate, coumarin, diethyldithiocarbamic acid, troleandomycin, and furafylline) and specific cDNA-expressed P450s were used to identify the major isoforms responsible for the oxidation of SPZS to SPZ and SPZ to SPZO. Both P450 2C9 and P450 3A4 were responsible for the oxidation of SPZS to SPZ, whereas P450 3A4 alone catalyzed the further oxidation of SPZ to SPZO. SPZS was found to be metabolized by P450 2C9 to SPZ with a high degree of enantiomeric selectivity (9:1) and a K(m) comparable with its previously determined K(i) for inhibition of the P450 2C9-dependent 7-hydroxylation of (S)-warfarin (WARF). In contrast, the P450 3A4-catalyzed oxidation of SPZS to SPZ proceeded with the same enantioselectivity but to a much lesser degree (58:42). These results provide evidence that the metabolism of both (S)-WARF and SPZS is mediated by a common enzyme, P450 2C9, which is central to understanding the WARF-SPZ interaction and SPZS-mediated drug interactions in general.

Chromatography, High Pressure Liquid↗

PubMed2001

[Location expression of human telomerase reverse transcriptase in lung cancer, benign lesion and normal lung tissue].

OBJECTIVE: To evaluate the diagnostic role of telomerase in benign and malignant lesion of lung and its biological significance in normal lung tissues. METHODS: Tissues studied consisted of 38 specimens of lung cancer, 35 adjacent non-neoplastic tissue and 7 benign parenchymatous lesion. Telomerase activity was determined using a semiquantitative polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay. Localization of telomerase reverse transcriptase (hTERT) expression was examined by in situ hybridization and immunohistochemistry. RESULTS: Telomerase activity was detected in 31 out of 38 lung cancer, 7 of 35 adjacent non-neoplastic lung tissue and 3 of 7 benign parenchymatous lesions (P < 0.001). Both hTERT protein and mRNA were detected in cancer cells, lymphocytes, fibroblasts, macrophages in benign parenchymatous tissue, epithelial cells of small airways, bronchiole, alveoli as well as lymph nodule germinal center of the adjacent normal tissues. There was no significant difference in the expression intensity of hTERT protein among different kinds of cells. There was a tendency that the expression intensity of hTERT protein was higher in squamous carcinoma than those in adenocarcinoma and stronger at TNM stage III with poorly differentiated than those at TNM stage I-II with well-differentiated squamous carcinomas and adenocarcinomas (P > 0.05). CONCLUSIONS: (1) Telomerase is involved in the pathogenesis of both lung cancer and benign parenchymatous lesion. (2) Telomerase expression may be of biological significance in maintaining the normal function of airway epithelial cells, alveolar macrophage and lymphocytes. (3) It is suggested that telomerase might be used as a proliferative marker, rather than a specific malignant marker. False positive response may occur using telomerase as a diagnostic marker.

Adult↗

PubMed2001

[Telomerase activity in lung cancer and adjacent peritumoral tissues determined by TRAP-SYBR green assay].

OBJECTIVE: To develop methods for the qualitative analysis of telomerase activity by TRAP-SYBR Green assay and study telomerase activity in lung cancer and adjacent peritumoral tissues, and to explore the possible association with expression of P53. METHODS: Thirty six lung cancer tissues and 36 adjacent peritumoral tissues, 8 lung benign lesion tissues and A549 lung adenoma cell line, were examined for telomerase activity by TRAP-SYBR Green assay. The 36 lung cancer tissue samples were also examined for P53 protein expression by immunohistochemical staining. RESULTS: Telomerase activity in 5 cells of A549 lung cancer cell line was detected by TRAP-SYBR Green assay. Thirty of 36 (83.3%) lung cancer specimens, seven of 36 (19.4%) adjacent peritumoral tissues, three of 8 (37.5%) lung benign lesion tissues were positive for telomerase activity. Telomerase activity of lung cancer did not correlate with pathologic type, tumor size and clinical stage. P53 was over-expressed in 24 of the 30 (80%) lung cancer samples with telomerase activity. A significant correlation was found between telomerase activity and accumulation of P53 proteins (r = 00.60, P < 0.01). CONCLUSION: TRAP-SYBR Green assay may be a sensitive, fast and convenient method for qualitative analysis of telomerase activity, which is useful in diagnosis lung neoplasms. The relationship between telomerase activity and P53 accumulation needs further study.

Fluorescent Dyes↗

PubMed2001

Comparison of the effects of two types of intraocular lens.

OBJECTIVE: To evaluate the effectiveness and safety of implantation of flexible open-loop anterior chamber intraocular lens (FOAC-IOLs) and scleral fixated posterior chamber intraocular lens (PC-IOLs). METHODS: Sixty-eight eyes of 68 patients with implanted intraocular lenses in the absence of posterior capsular support were reviewed retrospectively. According to the type of intraocular lens, patients were classified into two groups. In group I (30 eyes), FOAC-IOLs was implanted primarily or secondarily. In group II (38 eyes), scleral fixated PC-IOLs was implanted primarily or secondarily. By gonioscopy and ultrasound biomicroscopy (UBM), accurate positions of IOLs' haptics and the relationship between the haptics and surrounding tissues were observed postoperatively and used to evaluate the influence of the two types of IOLs on ocular anterior segments. Follow-up was 6 to 20 months. RESULTS: Best corrected visual acuity of 20/40 or better was achieved in 27 eyes (90.0%) in group I, and 35 eyes (92.1%) in group II and the difference was not statistically significant (P > 0.05). In group I, 23 eyes (76.7%) had a total of 40 complications, while 13 eyes (34.2%) had 19 complications in group II (P < 0.05). Gonioscopy and ultrasound biomicroscopy showed that in group I, all haptics of IOLs contacted with the iris completely and compressed the iris to different degrees, sometimes causing the anterior chamber angles to widen. Anterior synechia of the iris was caused by the haptics of FOAC-IOLs in 12 eyes. Among the 60 IOLs haptics, 39 foot plates of the haptics were properly fixed at the ciliary band; 21 haptics (12 eyes) penetrated through the iris into the stroma of the ciliary body with accompanying recurrent uveitis. In group II, among the 76 IOLs haptics, 52 were adequately fixed in the ciliary sulcus regions, and 8 (8 eyes) were placed below the iris, causing goniosynechia. This type of angle closure was localized, with an open angle on each side of the haptics. The remaining 16 haptics were fixed onto the ciliary crown. CONCLUSIONS: The current sutured mode of scleral fixated PC-IOLs can not ensure that IOLs haptics are placed in the ciliary sulcus. The haptics of FOAC-IOLs compress the iris and may penetrate through the iris into the stroma of the ciliary body. This can cause peripheral iris anterior synechia and chronic recurrent uveitis. The implantation of scleral fixated PC-IOLs is safer and shows better effects than that of FOAC-IOLs.

Aged↗

PubMed2001

Clinical features of diffuse axonal injury.

OBJECTIVE: To analyze the mechanism of diffuse axonal injury (DAI) and study the relationship between DAI and brain concussion, brain contusion, and primary brain stem injury. METHODS: The clinical data and iconographic characteristics of 56 patients with DAI were analyzed retrospectively. RESULTS: Traffic accidents were the main cause of DAI. Among t he 56 cases, 34 were injured for at least twice, and 71.43% of the patients were complicated with contusion. CONCLUSIONS: It is considered that DAI is a common pattern of primary brain injury, which is often underestimated. And DAI includes cerebral concussion and primary brain injury, and is often complicated by cerebral cortex contusion. Therefore, it is very simple and practical to divide primary brain injuries into local and diffuse injuries.

Adolescent↗

PubMed2001

[Patient awareness study of elderly population in rural Guangdong].

OBJECTIVE: To investigate the patients' awareness on the eye diseases, treatment and major barriers for patients to seek eye care. METHOD: Randomly clustering sampling method was used for all the subjects aged 50 years and over, and their eyes were examined. All subjects with presenting visual acuity less than 0.1 in at least one eye underwent the test of the patient's awareness questionnaire developed in Aravind Eye Hospital, India. RESULTS: Five hundred and thirty-five (85.5%) visual impairment subjects were successfully interviewed. In 526 cases with the ocular disease course over 1 year, 95% of them were aware of the occurrence of eye diseases for more than 1 year. However, in the 448 cases with the ocular diseases treatable, only 24.2% of them realized that their eye diseases could be treated, while 73% of them did not know or did know right on the examination date. The major barriers for seeking eye care were economic reason, fear of operation, far distance from a hospital, etc. CONCLUSION: Patients' education and low price service are probably the effective methods to clear the roadblock on the way of improving the coverage of eye care.

Age Distribution↗

PubMed2001

[Effects of adaptive changes of vestibular system on cardiovascular regulation and orthostatic tolerance].

Astronauts may experience Space Adaptation Syndrome at the primary period in spaceflight. It is widely accepted that it is mainly caused by vestibular adaptive changes. The reverse changes of adaptation present after the return from weightlessness to normal 1 G. It may cause astronauts' postural instability and orthostatic intolerance. Evidences from animal model and some data from humans suggest that the vestibular system have influences on the sympathetic nervous system and cardiovascular control. The inputs that appear to be critical in producing these responses come from otolith receptors. The important medical problem--orthostatic intolerance in space medicine is mainly caused by cardiovascular abnormal control. It is possible that vestibular adaptive changes under microgravity may have its influence on the cardiovascular function and orthostatic intolerance.

Adaptation, Physiological↗

PubMed2001

[Estimation of gas chromatographic retention index for polycyclic aromatic hydrocarbons using VMDE].

A novel molecular distance-edge vector with 6 parameters was calculated for 100 polycyclic aromatic hydrocarbons (PAHs) based on the molecular interaction theory. It was found that there was a good linear relationship between the molecular distance-edge vector (VMDE) and the gas chromatographic retention index for the 100 PAHs, and the molecular modelling equation for the quantitative structure-retention relationship (QSRR) can be expressed as follows: IR = a + b VMDE, n = 100, r = 0.988, where a and b represent regression coefficients. The regression results showed that the molecular distance-edge vector is in good agreement with the results of molecular polarizability index to the gas chromatographic retention index for the polycyclic aromatic hydrocarbons.

Air Pollutants↗

PubMed2001

[Studies on the chemical components of Clematis chinensis].

AIM: To study the chemical components of the root of Clematis chinensis. METHODS: Various chromatographic techniques were used to separate and purify the components. Their structures were determined on the basis of spectral and chemical evidence. RESULTS: Two compounds were isolated and elucidated as: clemaphenol A (I) and dihydro-4-hydroxy-5-hyroxymethy-2(3H)- furanone (II). CONCLUSION: Compound I and II are new compounds.

4-Butyrolactone↗

PubMed2000

Identification of c-myc responsive genes using rat cDNA microarray.

c-Myc functions through direct activation or repression of transcription. Using cDNA microarray analysis, we have identified c-Myc-responsive genes by comparing gene expression profiles between c-myc null and c-myc wild-type rat fibroblast cells and between c-myc null and c-myc null cells reconstituted with c-myc. From a panel of 4400 cDNA elements, we found 198 genes responsive to c-myc when comparing wild-type or reconstituted cells with the null cells. The plurality of the named c-Myc-responsive genes that were up-regulated, including 30 ribosomal protein genes, are involved in macromolecular synthesis and metabolism, suggesting a major role of c-Myc in the regulation of protein synthetic and metabolic pathways. When ectopically overexpressed, c-Myc induced a different and smaller set of c-Myc-responsive genes as compared with the physiologically expressed c-Myc condition. Thus, these results from expression profiling suggest a new primary function for c-Myc and raise the possibility that the physiological and transforming functions of c-myc may be separable.

Animals↗

PubMed2000

Visual sensing of saccharides promoted by resorcinol condensation products

[structure: see text] Heating aqueous DMSO solutions of five saccharides in the presence of 1-3 reveals that each receptor promotes solution colors characteristic for each sugar. New compound 3 allows the direct correlation of sugar concentration with visible region absorbance and/or fluorescence intensities.

Journal Article↗

PubMed2000

Mass spectrometric study of gamma-aryl-alpha,-gamma-diethoxy-alpha, beta-butenolides.

Electron impact mass spectra of eight of the title compounds are reported. Abundant fragment ions were produced under electron impact (EI) conditions and, with one exception, the ($¿hbox¿ArC¿¿equiv$ O) ions were the base peaks. The EI fragmentation mechanisms of two representative compounds were studied with the aid of high-resolution and mass-analyzed ion kinetic energy spectrometry (MIKES) data. The M(+) ions fragment to give both an odd-electron ion and an even-electron fragment ion. Two H-atom rearrangements proceeding via four-membered ring intermediates and three losses of CO through i- and alpha-fragmentations were observed under EI. On comparing fragmentations under EI conditions with those under FAB conditions for two of the compounds, the fragmentation mechanisms were reasonably similar, with additional fragmentations rationalized in terms of the ionization proton being located on the oxygen atom of the beta-ethoxy group.

4-Butyrolactone↗

PubMed2000

Mass spectrometric study of six cyclic esters

A series of cyclic esters, which are optically active as a consequence of their helical structures, were synthesized to investigate the relationships between their structures and their optical activities. This paper reports the electron impact fragmentation mechanisms of these six cyclic esters. Accurate mass measurements and mass analyzed ion kinetic energy spectrometry confirmed fragmentation patterns. The stability of the fragment ions has a great influence on the fragmentation pathways, but no correlation with the optical activity was found.

Journal Article↗

PubMed2000

Characterization of mesogen-jacketed liquid crystalline polymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

For synthetic polymers, a proper sample preparation method is essential for successful characterization by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. In this work, six synthetic mesogen-jacketed liquid crystalline polymers (MJLCPs) with different main-chain, spacer and mesogenic units were investigated by MALDI-TOF mass spectrometry. Several factors that affect the analysis of these polymers were examined. These factors include matrices used, cationization salts used, the concentration of polymers, and the ratio of sample to matrix. After testing different conditions, we found a suitable sample preparation method for these six polymers. The number average molecular weight (M(n)), weight average molecular weight (M(w)) and polydispersity (PD) were calculated using data obtained in the linear mode. The end groups of the polymers were proposed using data obtained in reflectron mode. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗

PubMed2000

Electron impact fragmentation mechanisms of some cyclic esters with helical structures

The electron impact mass spectra of several cyclic esters with helical structures have been studied. Their fragmentation pathways were proposed and confirmed by mass-analyzed ion kinetic energy (MIKE) and high-resolution data. In general, the dominant fragmentation pathways in the spectra of these compounds originate from a alpha-cleavage with loss of a hydrogen or methyl group. The difference between hydrogen and methyl group loss greatly affects the subsequent fragmentations. Although, due to their helicity, these cyclic esters are optically active no stereo-related fragmentation pathway was observed. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗

PubMed2000

The influence of curcumin on the cell cycle of HL-60 cells and contrast study.

The mechanisms of curcumin inhibiting the proliferation of HL-60 cells were investigated. Acute myeloid leukemic cell line HL-60 was studied by using cell culture, NBT reduction, SABC method measuring BrdU incorporation rate, FCM measuring DNA contents and TUNEL method determining apoptotic cell percentage. Curcumin inhibited proliferation of HL-60 cells in a dose- and time-dependent manner. When the HL-60 cells were treated with 25 mumol/L curcumin for 48 h, the inhibitory rate was 60.71% +/- 1.20%. The study on BrdU incorporation rate and the distribution of DNA content and NBT reduction indicated that curcumin arrested the cells in G2/M phase of cell cycle at first, then in G0/G1 phase, the whole cell cycle progression was slowed down and DNA synthesis activities was halted. The arrested cells went to apoptosis instead of differentiation. The comparative study indicated that the ability of curcumin regulating the cell cycle of HL-60 cells was stronger than As2O3 and the acting points of curcumin were not completely consistent with those of VP-16. It was suggested that curcumin was able to regulate, to some extent, the G1/S and G2/M transmit checkpoints and disturb the HL-60 cell cycle to induce apoptosis.

Antineoplastic Agents↗

PubMed2000

Fundus microvascular flow monitoring during retrograde cerebral perfusion: an experimental study.

BACKGROUND: Retrograde cerebral perfusion (RCP) through the superior vena cava was clinically introduced as a supportive technique to protect the brain during deep hypothermic circulatory arrest. This study searched for a direct monitor of cerebral blood flow to evaluate the effect of cerebral perfusion. METHODS: Retinal microvascular perfusions were studied in six piglets using fundus fluorescein angiography (FFA) and color Doppler sonography before cardiopulmonary bypass and retrograde cerebral perfusion during deep hypothermic circulatory arrest. RESULTS: FFA showed initial filling of the fundus venae in 2.5 minutes, and complete filling in 4.5 minutes with partial filling of the arteriae. Arteriae completely filled in 8 minutes, and all of the arteriae and venae filled from 15 to 17 minutes. Color Doppler sonography showed that flow signals were detected in all of the fundus vessels during RCP. CONCLUSIONS: FFA and color Doppler sonography are direct and sensitive methods for observing cerebral blood flow and assessing the effect of cerebral perfusion.

Animals↗