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Biomedical subjects

J Zhao

Publications and source records attributed to J Zhao.

At least 127 records · Page 7Linked to original sources
PubMed2001

Reduction in recurrence risk for involved or inadequate margins with edge cryotherapy after liver resection for colorectal metastases.

HYPOTHESIS: The usefulness of additional edge cryotherapy after liver resection for liver metastases from colorectal cancer to improve involved or inadequate (less than 1 cm) margins is uncertain. DESIGN: Retrospective analysis of prospectively collected data. SETTING: Department of surgery at a university hospital. PATIENTS: Eighty-six consecutive patients with hepatic metastases from colorectal cancer in whom we applied additional edge cryotherapy to involved or inadequate margins. This group was compared with 134 patients who underwent resection without edge cryotherapy (control group) during the same period. INTERVENTION: Potentially curative treatment was achieved by adding edge cryotherapy to insufficient resection sites in patients not eligible for further resection. MAIN OUTCOME MEASURES: Edge recurrence rate in the study group; validation of an additional treatment to improve curative resectability; and comparison of morbidity and local recurrence rates with the control group. RESULTS: At a median follow-up of 39 months, 47 patients were alive and 39 had died. Local recurrence at the resection site was diagnosed in 9 patients (10%), of which 7 occurred in patients with involved margins and 2 in patients with resection margin less than 1 cm. Thirty-six patients (42%) experienced recurrence in the remnant liver. Extrahepatic recurrence occurred in 38 patients (44%), the lungs being the most common site (22 patients [26%]). CONCLUSIONS: Edge cryotherapy is a potent additional surgical treatment option in patients with liver metastases from colorectal cancer. The percentage of patients who can be treated for cure can be increased, especially if complex liver surgery is demanded.

Adult↗
PubMed2001

Insulin-like growth factor-I (IGF-I) stimulates the development of cultured rat pre-antral follicles.

The aim of the present study is to investigate the effect of insulin-like growth factor (IGF-I) on the development of cultured rat pre-antral follicles. Pre-antral follicles with a diameter between 140 and 160 microm are mechanically isolated from ovaries of 10-day-old rats and cultured in groups for 6 days in FSH and insulin-containing serum-free medium in the absence or presence of IGF-I at concentrations of 1, 10, and 100 ng/ml, respectively. DNA content of the follicles before and after culture is measured to evaluate whether a possible growth is due to proliferation of follicular cells and the ultrastructure of the cultured follicles is studied with transmission electron microscopy to evaluate the quality of follicles cultured under different conditions. Furthermore, reverse transcriptase polymerase chain reaction (RT-PCR) is used to assess the gene expression of IGF-I and type I IGF receptor in pre-antral follicles. When follicles were cultured in medium containing IGF-I at a concentration of 1 and 10 ng/ml, the increase in follicle diameter after a 6-day culture differs significantly from that in the absence of IGF-I. The ultrastructure of follicles cultured in IGF-I-containing medium is better sustained when compared to that of follicles cultured in the absence of IGF-I. Especially, theca cells, which are undergoing degeneration under controlled culture condition, demonstrate normal cellular ultrastructure with some characteristics of steroid-secreting cells in the presence of IGF-I. Moreover, in oocytes of follicles cultured in the presence of IGF-I, cortical granules are observed distributed along the ooplasma membrane whereas cortical granules are hardly present in follicles cultured without IGF-I. With RT-PCR, the presence of the mRNA of IGF-I and type I IGF receptor is demonstrated in both the somatic follicular cells and the oocytes. Taken together, these results suggest that IGF-I, in the presence of follicle-stimulating hormone (FSH), enhances rat pre-antral follicle development in vitro and supports the morphology of cultured pre-antral follicles. The stimulatory effect of exogenous IGF-I on the development of pre-antral follicle together with the gene expression of both IGF-I and type I IGF receptor in pre-antral follicles suggests the involvement of IGF-I in early folliculogenesis and its actions are likely mediated by the putative type I IGF receptor, via both endocrine and paracrine/autocrine pathways.

Animals↗
PubMed2001

Determination of synthesized alpha-vitamin E by micellar electrokinetic chromatography.

We developed a micellar electrokinetic chromatography method (MEKC) for the direct determination of the content of synthesized alpha-vitamin E. It was found that under the optimum separation conditions 7 mM borate + 14 mM phosphate + 15 mM sodium dodecyl sulfate (SDS) + 10 mM sodium cholate (NaCh) + 8% acetonitrile (pH 9.2) with UV detection wavelength at 214 nm, 16 kV constant voltage, and 26 degrees C constant temperature, alpha-vitamin E and its isomers can be baseline separated and alpha-vitamin E was quantitatively analyzed. In addition, the sample recovery, the limit of detection and the repeatability of the method were investigated. The influence of various parameters on the separation such as SDS concentration, NaCh concentration, buffer pH and acetonitrile percentage were also discussed.

Acetonitriles↗
PubMed2001

Genomic imbalances in the progression of endocrine pancreatic tumors.

Endocrine pancreatic tumors (EPTs) are neoplasms with malignant potential. To explore the molecular basis of metastatic progression in human EPTs, we analyzed 17 paired specimens of primary EPTs and their metastases and 28 nonmetastatic EPTs using comparative genomic hybridization (CGH). Genomic alterations were detected in all of the matched primary/metastatic tumors and 19 (58%) nonmetastatic EPTs. The mean number of genomic changes was 17.3 in metastases, 12.5 in their primary tumors, and 4.5 in nonmetastatic EPTs. Statistical analysis of shared genomic changes in matched pairs of primary tumors and metastases showed a high probability (>95%) of a clonal relationship in 15 of the 17 cases. A closely related genetic pattern was also demonstrated on the basis of concordance analysis of the two groups. The most striking genomic changes which were enriched in metastases included gains of chromosomes 4 and 7 and losses of 21q. Other common regions of frequent losses (>40%) identified in metastases and/or their primary tumors involved 2p, 2q, 3p, 3q, 6q, 10p, and 11p, whereas frequently detected gains (>40%) in the paired tumors involved 5p, 5q, 12q, 14q, 17q, 18q, and 20q. These chromosomal aberrations were found in significantly fewer nonmetastatic EPTs. Some of these chromosomal loci may harbor genes contributing to the progression of EPT.

Adenoma, Islet Cell↗
PubMed2001

Population based linkage disequilibrium mapping of QTL: an application to simulated data in an isolated population.

Despite successes in mapping and cloning genes involved in rare Mendelian diseases, genetic dissection of quantitative traits into single Mendelian factors still remains a challenging task. As the dense map of single nucleotide polymorphism (SNP) markers becomes available in the near future, linkage disequilibrium (LD) mapping will become one of major tools for mapping and identifying quantitative trait loci (QTL). In this report, we present a population-based linkage disequilibrium mapping of QTL. This method unifies the analysis of mapping QTL in humans and in model organisms and can be used for randomly sampled individuals. The proposed method is applied to search for polymorphism sites within the candidate genes 2 and 6, which influence quantitative traits Q1 and Q2 or Q5, in a simulated data set in an isolated population.

Chromosome Mapping↗
PubMed2001

Different catalytic properties and inhibitor responses of the goldfish brain and ovary aromatase isozymes.

The brain and ovarian aromatase isozymes of goldfish (Carassius auratus) are encoded by different CYP19 genes. This study measured aromatase activity in the goldfish brain tissues. For a direct comparison of the properties of the two aromatase isozymes, Chinese hamster ovary cells were stably transfected with brain- and ovary-derived cDNAs (respectively, p450 arom B and -A) and the properties of the expressed isozymes were compared. The kinetic parameters of the two isozymes were determined using androstenedione and testosterone as substrates and compared to those of human aromatase. Inhibition profile analyses on the two isozymes were performed using seven inhibitors [4-hydroxyandrostenedione, 7 alpha-(4'-amino)phenylthio-1,4-androstadiene-3,17-dione, bridge (2,19-methyleneoxy)androstene-3,17-dione, aminoglutethimide (AG), CGS 20267, ICI D1033, and vorozole]. Except for AG, the compounds tested were found to be much stronger inhibitors against the ovary enzyme than the brain enzyme. In addition, the ovary isoform was more sensitive to two phytoestrogens, chrysin and 7,8-dihydroxyflavone, than the brain form. These studies reveal that catalytic properties of the goldfish aromatase isoforms are significantly different from those of human aromatase. In addition, differences in the K(i) values of aromatase inhibitors for the two goldfish isoforms suggest structural variance in the active sites of these isozymes.

Androstenedione↗
PubMed2001

Feature (gene) selection in gene expression-based tumor classification.

There is increasing interest in changing the emphasis of tumor classification from morphologic to molecular. Gene expression profiles may offer more information than morphology and provide an alternative to morphology-based tumor classification systems. Gene selection involves a search for gene subsets that are able to discriminate tumor tissue from normal tissue, and may have either clear biological interpretation or some implication in the molecular mechanism of the tumorigenesis. Gene selection is a fundamental issue in gene expression-based tumor classification. In the formation of a discriminant rule, the number of genes is large relative to the number of tissue samples. Too many genes can harm the performance of the tumor classification system and increase the cost as well. In this report, we discuss criteria and illustrate techniques for reducing the number of genes and selecting an optimal (or near optimal) subset of genes from an initial set of genes for tumor classification. The practical advantages of gene selection over other methods of reducing the dimensionality (e.g., principal components), include its simplicity, future cost savings, and higher likelihood of being adopted in a clinical setting. We analyze the expression profiles of 2000 genes in 22 normal and 40 colon tumor tissues, 5776 sequences in 14 human mammary epithelial cells and 13 breast tumors, and 6817 genes in 47 acute lymphoblastic leukemia and 25 acute myeloid leukemia samples. Through these three examples, we show that using 2 or 3 genes can achieve more than 90% accuracy of classification. This result implies that after initial investigation of tumor classification using microarrays, a small number of selected genes may be used as biomarkers for tumor classification, or may have some relevance in tumor development and serve as a potential drug target. In this report we also show that stepwise Fisher's linear discriminant function is a practicable method for gene expression-based tumor classification.

Humans↗
PubMed2001

Improved beta-thujaplicin production in Cupressus lusitanica suspension cultures by fungal elicitor and methyl jasmonate.

Production of a novel antimicrobial tropolone, beta-thujaplicin, in Cupressus lusitanica suspension cultures was studied by using a variety of chemicals and fungal elicitors. Sodium alginate, chitin, and methyl jasmonate resulted in 2-, 2.5-, and 3-fold higher beta-thujaplicin production, respectively, than in the control. Significantly improved beta-thujaplicin production (187 mg l(-1)) was obtained using a high cell density (180-200 g l(-1)) and fungal elicitor treatment [10 mg (g fresh cells)(-1)] in a production medium with a high ferrous ion concentration (0.3 mM). This improved volumetric productivity was 3- to 4-fold higher than obtained under standard conditions. A synergistic effect of fungal elicitor and ferrous ion on beta-thujaplicin production was also suggested by our study. Plant cell culture technology is a promising alternative for producing a large variety of secondary metabolites that are widely used as food additives, pharmaceuticals, and dairy products (Verpoorte et al. 1999). Thus, beta-thujaplicin production by plant cell cultures was developed with the goal of commercial application (Berlin and Witte 1988; Itose and Sakai 1997; Ono et al. 1998). However, the production of beta-thujaplicin by plant cell cultures is still not competitive for use in industrial applications. In this study, we assessed the effects of methyl jasmonate, alginate, chitin, and fungal elicitor on beta-thujaplicin production; we obtained a significantly elevated beta-thujaplicin production by using an improved culture strategy.

Acetates↗
PubMed2001

Effects of stress factors, bioregulators, and synthetic precursors on indole alkaloid production in compact callus clusters cultures of Catharanthus roseus.

Compact callus cluster (CCC) cultures established from Catharanthus roseus consist of cohesive callus aggregates displaying certain levels of cellular or tissue differentiation. CCC cultures synthesize about two-fold more indole alkaloids than normal dispersed-cell cultures. Our studies here show that additions of KCl, mannitol, and a variety of synthetic precursors and bioregulators to the CCC cultures markedly improved indole alkaloid production and release of these alkaloids into the medium. Treatment with 250 mM mannitol and 4 g/l KCl yielded 42.3 mg l(-1) and 33.6 mg l(-1)of ajmalicine, respectively; these amounts were about four-fold higher than the control. Succinic acid, tryptamine, and tryptophan feedings also significantly increased ajmalicine (41.5 mg l(-1), 36.9 mg l(-1), and 31.8 mg l(-1), respectively) and catharanthine (21.1 mg l(-1), 17.2 mg l(-1), and 18 mg l(-1), respectively) production by the CCC cultures, while geraniol feeding inhibited biomass and alkaloid accumulation. We also found that tetramethyl ammonium bromide could significantly improve ajmalicine production (49.3 mg l(-1)) and catharanthine production (18.3 mg l(-1)) in C. roseus CCC cultures. The mechanisms responsible for these treatment effects are discussed herein.

Acyclic Monoterpenes↗
PubMed2001

An anatomical study of the recurrent laryngeal nerve: its branching patterns and relationship to the inferior thyroid artery.

The aim of this study was to provide information about the morphology and topography of the recurrent laryngeal nerve (RLN), its external features and branches, as well as its relationship to the inferior thyroid artery, the inferior horn of the thyroid cartilage and the thyroid gland. The RLNs in 50 adult cadavers (100 sides) were dissected and analyzed. A communicating loop connecting one branch of the RLN to another or a twig originating from the cervical sympathetic trunk was present in 13 of 100 sides. A double left RLN appeared in 2 sides; a right non-recurrent inferior laryngeal nerve appeared in one side. All of the RLNs, including looped ones, bifurcated into laryngeal branches and extralaryngeal branches, with most of the former further dividing into the anterior and posterior branches entering the larynx. The relations of the RLN to the inferior thyroid artery, the inferior horn of the thyroid cartilage and the thyroid gland were inconstant. The information gained from this study will be of value in thyroid surgery.

Adult↗
PubMed2001

Gains of 12q13-14 and overexpression of mdm2 are frequent findings in intimal sarcomas of the pulmonary artery.

The characterization of clinical, histopathological, immunohistochemical, and genetic features of intimal sarcomas arising in the pulmonary artery is presented in this study. Four resected lungs, one endarterectomy specimen and three biopsies from eight patients (four males and four females; median age 41 years) suffering from intimal sarcomas of the pulmonary artery using conventional stains, immunohistochemistry, and comparative genomic hybridization (CGH) were analyzed. The predominant clinical presentation was dyspnea (all eight patients) and febrile pulmonary disease (six of eight). Signs of embolic lung disease were present in all patients. One patient died postoperatively, six patients died of disease 8-35 months after presentation, and one patient was alive 6 months after surgery. Histopathological examination of the submitted material showed spindle cell, partially myxoid and pleomorphic sarcomas. Metastases were histologically confirmed in three patients (lung, pleura, and skull). Immunohistochemically, vimentin was strongly expressed in all tumors. Focal positivity was observed for alpha smooth muscle actin, CD117, CD68, p53, and bcl2. No reaction could be obtained for endothelial markers. The proliferation index Ki-67 was between 5% and 80%. Six examined tumors were positive for mdm2. In the CGH analysis, gains and amplifications in the 12q13-14 region were found in six of eight tumors (75%). Other, less consistent alterations, were losses on 3p, 3q, 4q, 9p, 11q, 13q, Xp, and Xq, gains on 7p, 17p, and 17q, and amplifications on 4q, 5p, 6p, and 11q. Intimal sarcomas of the pulmonary artery are tumors with an unfavorable prognosis and poorly differentiated morphology. A majority of tumors show a consistent genetic alteration (gains and amplifications in the 12q13-14 region) and overexpression of mdm2, implicating the mdm2/p53 pathway as a possible mechanism in the tumor pathogenesis.

Actins↗
PubMed2001

Spitzoid malignant melanoma with lymph-node metastasis. Is a copy-number loss on chromosome 6q a marker of malignancy?

Distinction of spitzoid malignant melanomas (SMM) from Spitz nevi may be difficult or even impossible on the basis of conventional histology. In this report, a patient suffering from a primary lesion diagnosed as a Spitz nevus and a metastatic malignant melanoma approximately 4 years thereafter is described. A diagnosis of SMM was made subsequently upon review of the primary lesion. In the present analysis, we used comparative genomic hybridization (CGH) to define markers characteristic of SMM. The primary lesion revealed deletions on chromosomes 6q and 9p. In the metastasis, additional deletions on chromosomes 10p and 10q and gains of chromosome 7 were found. To our knowledge, no chromosomal aberration on chromosome 6 was hitherto demonstrated in benign melanocytic nevi. Findings reported in the literature suggest that human melanoma metastasis suppressor gene maps to 6q. In contrast, losses on chromosome 9p seem to be an early event in the development of melanoma. However, they are not only found in melanomas but are occasionally present in Spitz nevi as well as in atypical nevi. The CGH result with deletion of 6q in this difficult to diagnose primary melanocytic lesion strongly supports the diagnosis of malignant melanoma. To demonstrate the reliability of loss on chromosome 6q as a marker of SMM, a larger number of lesions must be investigated.

Adolescent↗
PubMed2001

Potential mechanism for the additivity of pilocarpine and latanoprost.

PURPOSE: To determine the ocular hypotensive mechanism underlying the additivity of latanoprost and pilocarpine. METHODS: This randomized, double-masked study included 30 patients with ocular hypertension on no ocular medications for at least 3 weeks. On each of six visits to the clinic, measurements were taken of aqueous flow and outflow facility by fluorophotometry, intraocular pressure by tonometry, and episcleral venous pressure by venomanometry. Uveoscleral outflow was calculated. Clinic visits were scheduled on baseline day; on day 8 of four times daily pilocarpine (2%) to one eye and vehicle to the other; on day 8 of continued pilocarpine/vehicle treatment plus latanoprost (0.005%) once daily to both eyes; after a 3-week washout period; on day 8 of once-daily latanoprost to one eye and vehicle to the other; and on day 8 of continued latanoprost/vehicle treatment plus pilocarpine four times a day to both eyes. Drug-treated eyes were compared with contralateral vehicle-treated eyes and with baseline day by paired t tests. Combined pilocarpine and latanoprost-treated eyes were compared with individual drug-treated eyes and with baseline day using the Bonferroni test. RESULTS: Compared with baseline, pilocarpine reduced intraocular pressure from 18.9 to 16.2 mm Hg (P =.001) and increased outflow facility from 0.18 to 0.23 microl per minute per mm Hg (P =.03). No other parameters were affected. Adding latanoprost further reduced intraocular pressure to 13.7 mm Hg (P <.001) and increased uveoscleral outflow from 0.82 to 1.36 microl per minute (P =.02). Latanoprost alone reduced intraocular pressure from 17.6 to 14.3 mm Hg (P <.0001) and increased uveoscleral outflow from 0.89 to 1.25 microl per minute (P =.05). Adding pilocarpine to the latanoprost treatment further reduced intraocular pressure to 12.7 mm Hg (P <.001) and increased outflow facility from 0.21 to 0.30 microl per minute per mm Hg (P =.03). CONCLUSIONS: Latanoprost and pilocarpine predominantly increase uveoscleral outflow and outflow facility, respectively, when given alone. These drugs are additive because pilocarpine does not inhibit the uveoscleral outflow increase induced by latanoprost.

Aged↗
PubMed2001

Differential loss of chromosome 11q in familial and sporadic parasympathetic paragangliomas detected by comparative genomic hybridization.

Parasympathetic paragangliomas (PGLs) represent neuroendocrine tumors arising from chief cells in branchiomeric and intravagal paraganglia, which share several histological features with their sympathetic counterpart sympathoadrenal paragangliomas. In recent years, genetic analyses of the familial form of PGL have attracted considerable interest. However, the majority of paragangliomas occurs sporadically and it remains to be determined whether the pathogenesis of sporadic paraganglioma resembles that of the familial form. Furthermore, data on comparative genetic aberrations are scarce. To provide fundamental cytogenetic data on sporadic and hereditary PGLs, we performed comparative genomic hybridization using directly fluorochrome-conjugated DNA extracted from 12 frozen and 4 paraffin-embedded tumors. The comparative genomic hybridization data were extended by loss of heterozygosity analysis of chromosome 11q. DNA copy number changes were found in 10 (63%) of 16 tumors. The most frequent chromosomal imbalance involved loss of chromosome 11. Six of seven familial tumors and two of nine sporadic tumors showed loss of 11q (86% versus 22%, P = 0.012). Deletions of 11p and 5p were found in two of nine sporadic tumors. We conclude that overall DNA copy number changes are infrequent in PGLs compared to sympathetic paragangliomas and that loss of chromosome 11 may be an important event in their tumorigenesis, particularly in familial paragangliomas.

Adult↗
PubMed2001

Sorption and cosorption of organic contaminant on surfactant-modified soils.

Three kinds of soils were modified with the cationic surfactants, hexadecyltrimethylammonium (HDTMA) bromide and tetramethylammonium (TMA) bromide to increase their sorptive capabilities. Sorption of chlorobenzene in simulated groundwater by these soils was investigated. HDTMA-modified soil has a higher ability to sorb chlorobenzene from simulated groundwater than unmodified soil. TMA-modified soil did not show the superiority. HDTMA thus can be used to modify soil to improve its sorption capability. Cosorption of chlorobenzene in simulated groundwater in the absence or presence of nitrobenzene and dichloromethane on HDTMA-modified soil was also investigated. Nitrobenzene facilitated sorption of chlorobenzene on all HDTMA-modified soil. Dichloromethane did not influence the sorption of chlorobenzene by HDTMA-modified soil. The results suggest that HDTMA-modified soil is a highly effective sorbent for chlorobenzene and multiple organic compounds did not impede the uptake of chlorobenzene.

Adsorption↗
PubMed2001

Photocatalytic degradation of dyes on a magnetically separated photocatalyst under visible and UV irradiation.

A novel kind of magnetically separable photocatalyst of TiO2/SiO2/gamma-Fe2O3 (TSF) is prepared. Scanning tunnel microscope (STM) and X-ray diffractometer (XRD) were used to characterize the structure of the photocatalyst. In the TSF photocatalyst, a TiO2 shell is for photocatalysis, a gamma-Fe2O3 core as a carrier is for separation by the magnetic field and a SiO2 membrane between the TiO2 shell and the gamma-Fe2O3 core is used to weaken the adverse influence of gamma-Fe2O3 on the photocatalysis of TiO2. Three kinds of dyes, Fluoresein, Orange II and Red acid G, were used to examine the photocatalytic activity of TSF. Due to strong UV adsorption of the gamma-Fe2O3, the photocatalytic activity of TSF was lower than that of the pure TiO2. Deducting the light absorption of the gamma-Fe2O3 particles, the photocatalytic activity of TSF was found to be higher than that of the P25 under UV irradiation. On the other hand, the photocatalytic activity of TSF under visible irradiation was much lower than that of the P25 TiO2 even deducting the visible light absorption of the gamma-Fe2O3 particles. Differences in the photocatalytic mechanisms under UV and visible irradiation lead to the differences in the photodegradation characteristics of dyes on TSF. The recycled TSF exhibited a good repeatability of photocatalytic activity.

Catalysis↗