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Biomedical subjects

M Gu

Publications and source records attributed to M Gu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Development and applications of a complete set of rice telotrisomics.

We previously isolated a complete set of primary trisomics along with many other aneuploids from triploid plants derived from an indica rice variety "Zhongxian 3037." About 30,000 progeny from these trisomic and aneuploid plants were grown each year from 1994 to 1999. The variants that differed morphologically from both the diploids and the original primary trisomics were collected for cytological identification. From these variants, a complete set of telotrisomics covering all 24 rice chromosome arms was obtained. The identities of the extra chromosomes were further confirmed by dosage analysis of the RFLP markers on extra chromosome arms. The telocentric nature of the extra chromosomes in these stocks was verified by fluorescence in situ hybridization (FISH) using a rice centromeric BAC clone as a marker probe. In general, the shorter the extra chromosome arm of a telotrisomic, the stronger the resemblance it bears to the diploid; the longer the extra chromosome arm, the stronger the resemblance to the corresponding primary trisomic. We demonstrated that DNA clones can be rapidly assigned to specific chromosome arms by dosage analysis with the telotrisomics. We also showed that telotrisomics are valuable tools for chromosome microdissection and for developing chromosome-specific DNA markers.

Chromosomes↗
PubMed2001

Toward a cytological characterization of the rice genome.

Rice (Oryza sativa L.) will be the first major crop, as well as the first monocot plant species, to be completely sequenced. Integration of DNA sequence-based maps with cytological maps will be essential to fully characterize the rice genome. We have isolated a set of 24 chromosomal arm-specific bacterial artificial chromosomes to facilitate rice chromosome identification. A standardized rice karyotype was constructed using meiotic pachytene chromosomes of O. sativa spp. japonica rice var. Nipponbare. This karyotype is anchored by centromere-specific and chromosomal arm-specific cytological landmarks and is fully integrated with the most saturated rice genetic linkage maps in which Nipponbare was used as one of the mapping parents. An ideogram depicting the distribution of heterochromatin in the rice genome was developed based on the patterns of 4',6-diamidino-2-phenylindole staining of the Nipponbare pachytene chromosomes. The majority of the heterochromatin is distributed in the pericentric regions with some rice chromosomes containing a significantly higher proportion of heterochromatin than other chromosomes. We showed that pachytene chromosome-based fluorescence in situ hybridization analysis is the most effective approach to integrate DNA sequences with euchromatic and heterochromatic features.

Chromosomes↗
PubMed2001

Degradation and drug delivery properties of poly(1,4-cyclohexanedicarboxylic anhydride).

Polyanhydrides for drug-controlled release systems from cis- and trans-1,4-cyclohexanedicarboxylic acid (1,4-CHDA) were synthesized by melt polycondensation. The degradation of polymers was estimated by weight loss in 0.1 mol l(-1), pH 7.4 phosphate buffer at 37 degrees C. The drug delivery was conducted in the same buffer. The results show that the different polymers lost weight over 150-360 h, and fine surface erosion was investigated. The different conformation of CHDA has an obvious influence on the degradation of polyanhydrides due to their different crystallinity, with higher crystallinity samples degrading much more slowly. The incorporation of adipic acids into the poly(CHDA) can obviously accelerate the degradation and the introduction of -CH2- segments increased the flexibility of polyanhydride backbone and accelerated the degradation rate. In vitro delivery experiments show that Bruffen was completely released in about 10 days from a melting mold disk with a fine linear delivery curve.

Anhydrides↗
PubMed2001

Three-dimensional coherent transfer function for reflection confocal microscopy in the presence of refractive-index mismatch.

The three-dimensional (3-D) coherent transfer function for reflection confocal microscopy of high-numerical-aperture objectives is derived and calculated in the presence of refractive-index mismatch when a laser beam is focused into a medium of refractive index different from its immersion medium. This aberrated coherent transfer function is then used to estimate the readout efficiency of 3-D data bits recorded in a thick medium. It is shown that the readout efficiency of confocal microscopy for 3-D bit data storage is decreased with the focal depth of an objective in a recording medium. However, a high readout efficiency can be maintained if the tube length of a reading objective is linearly altered to compensate for the spherical aberration caused by the refractive-index mismatch.

Microscopy, Confocal↗
PubMed2001

True malignant mixed tumor (carcinosarcoma) of parotid gland with unusual mesenchymal component: a case report and review of the literature.

True malignant mixed tumor (carcinosarcoma) of the salivary gland is an extremely rare tumor. By definition, it is composed of both malignant epithelial and malignant mesenchymal elements. The most common type of the former is squamous cell carcinoma or adenocarcinoma and the most common type of the latter is chondrosarcoma, followed in frequency by fibrosarcoma, leiomyosarcoma, osteosarcoma, and in rare instances liposarcoma. We report a case of true malignant mixed tumor of the parotid gland in association with a pleomorphic adenoma in a 47-year-old man that contained a very unusual type of malignant mesenchymal component, rhabdomyosarcoma. Cytologic and histologic features and immunohistochemical results are presented. In addition, the literature is reviewed, and the possible histogenesis and pathogenesis of malignant mixed tumor of the salivary gland are briefly discussed.

Actins↗
PubMed2001

[Expression of rasp21, C-myc, C-erbB-2, and AFP in 2-FAA induced experimental hepatocarcinogenesis].

OBJECTIVE: To investigate the distribution of oncogenes and their relationships in 2-FAA induced experimental hepatocarcinogenesis. METHODS: Rasp21, C-myc, C-erbB-2, and AFP were detected and analyzed by the SP method of immunohistochemistry. RESULTS: Some cells expressed rasp21, C-myc, and AFP in peripheral liver lobules and alternated hepatocyte foci in the early stage of the experiment. And with the formation and progression of hyperplastic hepatocytic nodules, expressed cells increased and often accompanied each other. Expression of C-erbB-2 appeared in the middle stage of the hepatocarcinogenesis. CONCLUSIONS: Expression of rasp21, C-myc, and AFP in the experimental hepatocarcinogenesis is an early molecule change, which may relate to the initiation of hepatocarcinogenesis and be considered to be one of the molecular bases for the morphogenesis of hepatocarcinogenesis. During the development of lesion, C-erbB-2 may have promoting effects. It is also clear that malignant transformation of hepatocyte needs the cooperation of multiple oncogenes.

2-Acetylaminofluorene↗
PubMed2001

Pressure assessment in intercavernous embedding of bulboperineal urethra for treatment of urinary incontinence after prostatic operation.

AIM: To put forward criteria for the pressure assessment in the operation of intercavernous embedding of bulboperineal urethra for the treatment of urinary incontinence after prostatic operation. METHODS: A F14 urethral catheter is inserted during the operation and upon suturing the corpora cavemosa centrally, the catheter is slowly pushed in and pulled out in order that the operator feels a certain degree of close-fit resistance. The degree of tightness of the stitches, which regulate the compression pressure, is adjusted in accordance with this close-fit sensation. To further ascertain the adequacy of the force of compression, the bladder is filled with 300 ml physiological saline and observe the appropriateness (size and continuity) of the outflow stream when the lower abdomen is depressed with a pressure of 80-90 cm H2O. The operation was given to six patients suffered from urinary incontinence for 20 or more months after prostatic operation. RESULTS: Five cases achieved complete recovery, while the therapeutic effect of the 6th one was not satisfactory. A second stage operation was carried out 3 months later with the addition of one more stitch both proximally and distally to reinforce the compression force. The condition was improved dramatically. The follow-up period averaged 3.5 years. CONCLUSION: The adequacy of the compression pressure exerted by the juxtaposed corpora cavernosa is the key point determining the outcome of the operation. The measures for assessing the compression pressure suggested by the authors are helpful in obtaining the good results of the present paper (6/6 success) as compared with 25/34 success in the previous report.

Aged↗
PubMed2001

[Study and drawing of standard curve of body height and weight for orthodontics].

OBJECTIVE: To study and trace the standard growth curve of body height and weight of adolescent in Shenzhen area for orthodontic diagnosis and treatment planning. METHODS: Based on the general assessment data of 21,120 students (7-18 years) in Shenzhen, the body height and weight were measured and the standard curve of body height and weight was drawn. RESULTS: Under 12 years, the annual increment of body height and weight was similar for both sexes. Above 12 years, the annual body height and weight increment of girls was slower than that of boys. The annual body weight increment peak was between 11-12 years for girls and 13 years for boys. CONCLUSIONS: The standard growth curve of body height and weight plays an important role in the orthodontic diagnosis and treatment planning.

Adolescent↗
PubMed2001

[Quantitative structure and activity relationship for epoxides].

Mutagenic activity data of 86 epoxides were collected from a CD system of Registry of Toxic Effects of Chemical Substances (RTECS 1998 Version). By using principal component analysis, the 5 kinds from 11 kinds of molecular structure descriptors, such as the number of carbon atom, the number of benzene-cycle, the number of hydrogen atom, the number of substituted alkyl group and the number of oxygen atom which can have influence on their mutagenic activity very much were chosen. After learning of above samples. The Back-Propagation Method(BP) network structure was optimized, the learning sets of sample were classified, then unknown samples were predicted one by one; for 86 samples, the correctly classified rate can reach to 92% between the low class and the high class. Results shown that the special molecular structure, the epoxides of polycyclic aromatic hydrocarbons contained 3-4 cycles, can be responsible for their very high mutagenic activities.

Epoxy Compounds↗
PubMed2001

[The study of skeletal mechanics of anterior crossbite evaluated with SN length].

OBJECTIVE: To study the stability of SN (anterior cranial base) length and the ability to evaluate upper lower jaws, and study the inner skeletal structure mechanism. METHODS: Interrelated angles, SN length, maxillary and mandible length were measured, the ratios between SN and maxillary and mandible length were compared with normal standard data, the data between mixed and permanent dentition groups were compared. RESULTS: No significant difference was found on SN length between anterior crossbite patients and normal sample. Significant difference was found between crossbite and normal data on the ratio of SN and maxillary length and mandible length. Based on evaluation of SN length, the crossbite can be divided into three types of skeletal structures including normal maxilla and longer mandible, short maxilla and normal mandible, short maxilla and longer mandible, the longer mandible is a main factor. CONCLUSION: With the advantage of stability, SN can be used to evaluate maxilla and mandible, and decide the skeletal mechanics of crossbite individually and accurately.

English Abstract↗
PubMed2000

Pharmacologic graft protection without donor pretreatment in liver transplantation from non-heart-beating donors.

BACKGROUND: Non-heart-beating donors (NHBDs) are considered potential sources of transplant organs in an effort to alleviate the problem of donor shortage in clinical liver transplantation. We investigated the possibility of pharmacologic protection of hepatic allograft function from NHBDs without donor pretreatment. METHODS: Orthotopic liver transplantation was performed using pigs. In donors, cardiac arrest was induced by stopping the respirator. Forty-five minutes after cessation of the respirator, the liver was flushed with cold lactated Ringer's solution including heparin and with the University of Wisconsin (UW) solution, and then preserved for 8 hr at 4 degrees C in the UW solution. The pigs were divided into two groups: a control group and a treated group. In the treated group, an endothelin antagonist TAK-044 was added to the UW solutions (10 mg/L), and TAK-044 (10 mg/kg body weight) and a platelet activating factor antagonist E5880 (0.3 mg/kg body weight) were also administered to the recipients. RESULTS: TAK-044 and E5880 treatment significantly increased the 7-day survival rate of the recipients (100% vs. 17%, P<0.05). In the treated group, portal venous pressure immediately after reperfusion of the graft was significantly lower than in the control group, and postoperative increase in serum concentrations of glutamic oxaloacetic transaminase and total bilirubin was attenuated. Moreover, the energy charge and adenosine triphosphate concentration of the liver were rapidly restored after reperfusion. CONCLUSIONS: Pharmacologic modulation with TAK-044 and E5880 avoiding donor pretreatment can improve the viability of hepatic allografts procured from NHBDs.

Animals↗
PubMed2000

Oxidative-phosphorylation defects in liver of patients with Wilson's disease.

BACKGROUND: Wilson's disease (WD) is caused by mutations in a P-type ATPase and is associated with copper deposition in liver and brain. The WD protein is present in the trans-Golgi network and may also be imported into mitochondria. The WD protein functions as a P-type copper transporting ATPase in the Golgi but any action in mitochondria is at present unknown. METHODS: We studied mitochondrial function and aconitase activity in WD liver tissue and compared the results with those in a series of healthy controls and patients without WD. FINDINGS: There was evidence of severe mitochondrial dysfunction in the livers of patients with WD. Enzyme activities were decreased as follows: complex I by 62%, complex II+III by 52%, complex IV by 33%, and aconitase by 71%. These defects did not seem to be secondary to penicillamine use, cholestasis, or poor hepatocellular synthetic function. INTERPRETATION: The results show that there is a defect of energy metabolism in WD. The pattern of enzyme defects suggests that free-radical formation and oxidative damage, probably mediated via mitochondrial copper accumulation, are important in WD pathogenesis. These results provide a rationale for a study of the use of antioxidants in WD.

Adolescent↗
PubMed2000

Association between initial diagnostic procedure and hysteroscopy and abnormal peritoneal washings in patients with endometrial carcinoma.

BACKGROUND: Hysteroscopy has been implicated in the finding of positive peritoneal washings (PW) in patients with endometrial carcinoma in several case reports. The current study was designed to evaluate whether there was an increased incidence rate of positive peritoneal washings in patients after hysteroscopy compared with patients who did not undergo hysteroscopy. METHODS: Two hundred eighty-four women with endometrial carcinoma were treated by hysterectomy with intraoperative PW at the Memorial Sloan-Kettering Cancer Center between 1995-1998. They were diagnosed by either endometrial biopsy (EMB) or dilatation and curretage (D & C) with or without hysteroscopy during the same period. RESULTS: Of 173 patients diagnosed by EMB, 16 had abnormal PW (9.2%). Of 111 patients diagnosed by D & C, 11 had abnormal PW (9.9%). There was no significant difference between the two groups (P = 0.85). Of 23 patients who were diagnosed by D & C with hysteroscopy, 3 had abnormal PW (13.0%). Of 177 patients who did not undergo hysteroscopy, 17 had abnormal PW (9.6%). Of 84 patients for whom information regarding hysteroscopy was not available, 7 had abnormal PW (8.3%). The incidence rates among the three groups were not significantly different (P = 0.79). CONCLUSIONS: The initial diagnostic procedure, including hysteroscopy, does not appear to be associated with a high incidence rate of abnormal PW in patients with endometrial carcinoma.

Adult↗
PubMed2000

Nitric oxide increases p21(Waf1/Cip1) expression by a cGMP-dependent pathway that includes activation of extracellular signal-regulated kinase and p70(S6k).

Nitric oxide (NO) regulates the expression of p21(Waf1/Cip1) in several cell types. The present study examined the role of both the extracellular signal-regulated kinase (ERK) and p70 S6 kinase (p70(S6k)) in the NO-induced increase in p21 expression that occurred in adventitial fibroblasts during the cell cycle. Both ERK and p70(S6k) were phosphorylated in response to the NO donor S-nitroso-N-acetylpenicillamine (SNAP) and the activation was rapid, transient, and preceded increased p21 expresion under defined conditions where serum was present. Addition of a selective inhibitor of ERK phosphorylation (PD98059) prevented the subsequent phosphorylation of p70(S6k) and the increase in p21 protein. Both cGMP and cAMP activated both ERK and p70(S6k), whereas only selective inhibitors of protein kinase G prevented the activation of the kinases by SNAP. A complex between ERK and p70(S6k) was documented by immunoprecipitation procedures. Rapamycin blocked p70(S6k) phosphorylation induced by NO and also inhibited p53 phosphorylation and p21 expression whereas PD98059 only prevented the NO-induced increase in p21 protein without influencing either p53 activation or p21 mRNA expression. The studies show a unique relationship between NO, ERK, and p70(S6k) and also provide evidence for a novel role of p70(S6k) in the activation of p53.

Animals↗
PubMed2000

14-3-3zeta interacts with the alpha-chain of human interleukin 9 receptor.

Interleukin 9 (IL-9) exerts its pleiotropic effects through the IL-9 receptor (IL-9R) complex, which consists of the IL-9R alpha-chain, which determines the cytokine specificity, and the IL-2 receptor gamma-chain. In the present study we used a modified yeast two-hybrid system to isolate cDNA species encoding proteins that interacted with the intracellular domain of the human IL-9R alpha-chain (hIL-9Ralpha). We have identified 14-3-3zeta as an hIL-9Ralpha-interacting protein. We also mapped residues 518-522 (Arg-Ser(519)-Trp-Thr(521)-Phe) in hIL-9Ralpha and helix I of 14-3-3zeta as being important for interaction. Moreover, peptide competition experi-ments suggested that interaction between hIL-9Ralpha and 14-3-3zeta requires the phosphorylation of Ser(519) or Thr(521). This is the first demonstration that 14-3-3 can interact with a non-tyrosine kinase receptor. The interaction between 14-3-3 and IL-9Ralpha but not IL-4Ralpha also suggests a potential role for 14-3-3 in determining cytokine specificity.

14-3-3 Proteins↗
PubMed2000

Comparative study on three chemotherapeutic regimens for the treatment of advanced epithelial ovarian cancer.

To investigate the best first-line chemotherapy regimen for the treatment of advanced epithelial ovarian cancer (AEOC), the efficacy of three chemotherapy regimens for treatment of the patients with AEOC in our hospital during Jan. 1992-Jan. 1999 was retrospectively analyzed. The therapeutic effects were compared with the supplement of Melphalan + Hexamethylme (PAM + HMM), cisplatin + adriamycin + cyclophosphamide or isofamide (PAC) or cisplatin + cyclophosphamide or isofamide (PC), Taxol + cisplatin (TP) combined chemotherapy after cytoreductive surgery. The results showed that the overall effective rate of TP was significantly higher than that of PAM + HMM (P < 0.05); The complete remission rate of TP was significantly higher than that of PAM + HMM and PAC or PC (all P < 0.05); The 2-year survival rate free of tumor of TP was obviously higher than that of PAM + HMM and PAC or PC (all P < 0.05). It was concluded that the therapeutic effect of TP regimen in the treatment of AEOC was better than PAM + HMM and PAC or PC and TP regimen could be recommended currently as the preferred first-line one for the treatment of AEOC.

Adult↗
PubMed2000

Limiting Factors on Image Quality in Imaging through Turbid Media under Single-photon and Two-photon Excitation.

The effect of multiple scattering in a turbid medium on single-photon and two-photon fluorescence microscopy is experimentally investigated for different scattering characteristics including scattering anisotrophy and optical thickness of a turbid medium. It is demonstrated that two-photon excitation can provide significant improvement in penetration depth through turbid media, due to reduced scattering experienced by the excitation beam. It is also shown that the limiting factor in obtaining high-quality images under single-photon excitation is the fast degradation of image resolution caused by multiple scattering, while for two-photon excitation it is limited by the degradation of image contrast due to the reduction in fluorescence strength.

Journal Article↗