Biomedical subjects

Y Ke

Publications and source records attributed to Y Ke.

At least 19 recordsLinked to original sources

PubMed2002

Biexponential transverse relaxation (T(2)) of the proton MRS creatine resonance in human brain.

Differences in proton MRS T(2) values for phosphocreatine (PCr) and creatine (Cr) methyl groups (3.0 ppm) were investigated in studies of phantoms and human brain. Results from phantom studies revealed that T(2) of PCr in solution is significantly shorter than T(2) of Cr. Curve-fitting results indicated that the amplitude-TE curves of the total Cr resonance at 3.0 ppm in human brain (N = 26) fit a biexponential decay model significantly better than a monoexponential decay model (P < 0.006), yielding mean T(2) values of 117 +/- 21 ms and 309 +/- 21 ms. Using a localized, long-TE (272 ms) point-resolved spectroscopy (PRESS) proton MRS during 2 min of photic stimulation (PS), an increase of 12.1% +/- 3.5% in the mean intensity of the total Cr resonance in primary visual cortex (VI) was observed at the end of stimulation (P < 0.021). This increase is consistent with the conversion of 26% of PCr in VI to Cr, which is concordant with (31)P MRS findings reported by other investigators. These results suggest a significantly shorter T(2) for PCr than for Cr in vivo. This difference possibly could be exploited to quantify regional activation in functional spectroscopy studies, and could also lead to inaccuracies in some circumstances when the Cr resonance is used as an internal standard for (1)H MRS studies in vivo.

Adult↗

PubMed2002

Prostatic stem cells.

Multipotent cells within the epithelial compartment, together with phenotypically 'plastic' mesenchyma cells (stromal stem cells), provide a repository of protected genetic information from which the structure, stability and functionality of the prostate gland can be maintained. However, mere preservation of cells in a non-dividing state is insufficient to provide the necessary reservoir of information from which the structure and function of the prostate gland can be retained or recreated. Rather, there is a constant dynamic interaction, at the level of information exchange, between stem cells (whether epithelial or mesenchymal) and their surrounding environment (both humoral and physical). Thus, with respect to epithelial stem cells, these reside within environmental 'niches' which allow their controlled and limited proliferation while preserving genomic integrity. Similar 'mesenchymal niches' are also predicted to occur, although not yet identified, thus providing the multipotent source from which the full spectrum of stromal phenotypes might be regenerated. Recent data from studies of the haematopoietic and hepato-biliary systems indicate that the potential scope of stem cells far exceeds the immediate phenotypic complement of those tissues within which they originate, being dependent upon their precise environment as well as their genomic integrity.

Cell Differentiation↗

PubMed2002

Upregulation of estrogen and androgen receptors modulate expression of FGF-2 and FGF-7 in human, cultured, prostatic stromal cells exposed to high concentrations of estradiol.

This study was performed to develop an experimental model in which expression of estrogen receptors (ER) by human prostatic stromal cells could be reproducibly enhanced relative to similar cells with low ER expression. The second aim was to characterise changes in expression of ER, androgen receptor (AR), FGF-2 and FGF-7 in stromal cells exposed to high and low concentrations of estradiol and testosterone mimicking the different sex hormone levels between young and elderly men. Five strains of human prostatic stromal cells, isolated from BPH resections, were grown in steroid-free medium plus 1 micromol 17beta-estradiol. After 10 days, cells were passaged and grown in the same medium without estradiol until confluent. In a second study four cell strains were exposed to high and low concentrations of 17beta-estradiol and testosterone for 10 days. Cells were labelled with fluorescent antibodies to ERalpha, AR, FGF-2 and FGF-7 and the fluorescence intensity measured by flow cytometry. Following exposure to 1 micromol estradiol, stromal cells showed reduced expression of AR and ERalpha but after passage without estradiol they showed a 25% increase in both receptors over controls. Different combinations of sex hormones induced inconsistent changes with respect to expression of ER, AR and FGFs in the various cell-strains. However, there was a highly significant correlation between AR, ER and FGF-2 and FGF-7, which was cell strain-specific. Thus, changes in sex hormone balance per se may not be solely responsible for the observed increases in prostatic ER levels in BPH. Since expression of ER is correlated with synthesis of FGF-2 and FGF-7, it is likely that increases in stromal ER may mediate the synthesis of stromally-derived growth factors which contribute to the aetiopathogenesis of benign prostatic hyperplasia.

Culture Techniques↗

PubMed2001

Human cutaneous fatty acid-binding protein induces metastasis by up-regulating the expression of vascular endothelial growth factor gene in rat Rama 37 model cells.

Human cutaneous fatty acid-binding protein (C-FABP) gene is capable of inducing the metastatic phenotype when overexpressed in nonmetastatic rat Rama 37 cells. However, the mechanism of how it induces metastasis is not clear. Northern and slot blot analyses revealed that expression of the endogenous vascular endothelial growth factor (VEGF) gene was increased by 3.8-5.2-fold in the C-FABP-transfected cells (pSV-CFABP-R37) and in their metastatic sublines (e.g., Met-1) when compared with that in the nonmetastatic control transfectant pSV-R37 cells generated by transfection of only plasmid DNA. Higher levels of VEGF immunoreactive protein were also secreted from the malignant C-FABP-expressing cells. Reverse transcription-PCR detected two VEGF transcript isoforms, VEGF(164) and VEGF(188), in both the nonmetastatic control transfectant pSV-R37 cells and the malignant metastatic Met-1 cells. Chick chorioallantoic membrane assays showed that the conditioned medium of the control pSV-R37 cells possessed only very weak angiogenic activity, whereas conditioned media from the metastatic C-FABP transfectants and their sublines were strongly angiogenic and could be inhibited by antibodies to VEGF. Transfection of VEGF(164) cDNA in an expression vector into nonmetastatic Rama 37 cells produced a cell clone (R37-VEGF-2) that expressed high levels of VEGF. Inoculation of R37-VEGF-2 cells into syngeneic Wistar Furth rats produced metastases in a significant number (Fisher's exact test, P < 0.01) of animals (18 of 31 animals), whereas the control, vector alone-transfected R37-PSV cells produced no metastases (0 of 30 animals). Immunocytochemical methods demonstrated a strong positive staining for VEGF and an increased microvessel density in the primary tumors produced from PSV-VEGF-2 cells in comparison with tumors produced from control transfectants. Immunocytochemical staining for factor VIII detected a 3.5-fold increase in microvessel density of the primary tumors produced by PSV-VEGF-2 cells when compared with that of the primary tumors developed from the control pSV-R37 cells. Therefore, we suggest that overexpression of the C-FABP gene in the original transfectants induces metastasis through up-regulation of expression of the VEGF gene in this rat Rama 37 model system, and thus VEGF may play a crucial role in this particular metastatic cascade.

Animals↗

PubMed2001

African origin of modern humans in East Asia: a tale of 12,000 Y chromosomes.

To test the hypotheses of modern human origin in East Asia, we sampled 12,127 male individuals from 163 populations and typed for three Y chromosome biallelic markers (YAP, M89, and M130). All the individuals carried a mutation at one of the three sites. These three mutations (YAP+, M89T, and M130T) coalesce to another mutation (M168T), which originated in Africa about 35,000 to 89,000 years ago. Therefore, the data do not support even a minimal in situ hominid contribution in the origin of anatomically modern humans in East Asia.

Africa↗

PubMed2001

Exercise decreases cytosolic aconitase activity in the liver, spleen, and bone marrow in rats.

Effects of strenuous exercise on cytosolic aconitase activity (CAA) were investigated in this study. Female Sprague-Dawley rats were randomly assigned to four groups: S1 (Sedentary), S2 (Sedentary + L-NAME [N-nitro-l-arginine methyl ester]), E1 (Exercise), and E2 (Exercise + L-NAME). Rats in the E1 and E2 groups swam for 2 h/day for 3 months. L-NAME (an inhibitor of NOS) in drinking water (1 mg/ml) was administered to rats in the S2 and E2 groups for the same period. At the end of the third month, the CAA in the liver, spleen, and bone marrow cells was measured. In the exercise group (E1), CAA in the liver, spleen, and bone marrow cells was 19.99 +/- 1.49, 1.61 +/- 0.13, and 0.59 +/- 0.09 mU/mg protein, respectively. These values were significantly lower than the corresponding sedentary values in the S1 group (33.96 +/- 1.38, 3.96 +/- 0.19, and 3.20 +/- 0.18 mU/mg protein) (P < 0.01, 0.001, and 0.001, respectively). The treatment of L-NAME led to a significant increase in tissue CAA in the sedentary rats (S2). Also, the significantly higher CAA in the liver, spleen, and bone marrow cells was found in the exercised rats treated with L-NAME (E2) (29.50 +/- 1.27, 2.89 +/- 0.25, and 1.34 +/- 0.20 mU/mg) than without L-NAME (E1) (P < 0.01, 0.01, 0.05, respectively). However, the values in the E2 group were still significantly lower than those in the S1 group (P < 0.05, 0.01, and 0.001, respectively). This indicates that L-NAME treatment can partly recover the decreased CA in tissues in the exercised rats. These results provide evidence for the existence of the increased activity of IRP1 (iron regulatory protein 1) that is probably induced by the increased nitric oxide production in the strenuously exercised rats.

Aconitate Hydratase↗

PubMed2001

Ceruloplasmin promotes iron uptake rather than release in BT325 cells.

This study was initiated to investigate the mechanism of ceruloplasmin (CP)-mediated iron release from brain cells using BT325 cells (a glioblastoma cell line); however, negative results were obtained. The BT325 cells were preloaded with 1 microM 59Fe2+ in sucrose (pH 5.8) for 60 min, and then with CP (0-300 microg/ml) for 30 min at 37 degrees C. The addition of CP, either at low (25 microg/ml) or high (300 microg/ml) concentrations, did not lead to a significant change in iron release from iron-loaded BT325 cells. No significant difference in total iron of cells was found between all CP treated groups and the control (P>0.05). Although apotransferrin (apoTf) was shown to have a role in iron release from the cells, the effect of apoTf was not significantly affected by the addition of different concentrations of CP. When the cells were incubated with 1 microM 59Fe2+ in the presence of varying amounts of CP for 30 min at 37 degrees C, it was found that CP increased iron uptake. The total iron uptake by BT325 cells in CP treatment groups (25, 75, 150, 300 microg/ml) was significantly higher than that in the control (no CP addition) (all P<0.01). Furthermore, in contrast to our expectation, CP was shown to promote significantly iron uptake in not only iron-sufficient but also iron-deficient cells. These results showed that CP had a role in iron uptake rather than release in BT325 cells.

Animals↗

PubMed2001

Rethinking the role of ceruloplasmin in brain iron metabolism.

For more than three decades, it has been widely accepted that ceruloplasmin plays an important role in iron efflux from mammalian cells, including brain cells, via the activity of ferroxidase. However, in light of recent findings, this view might not be completely accurate and the role of ceruloplasmin in brain iron metabolism may need to be re-evaluated. Based on recent studies, we propose in this article that the role of ceruloplasmin in iron uptake by brain neuronal cells might be more important than its role in iron release from the cells. A possible explanation of why the absence of ceruloplasmin induces excessive iron accumulation in neurons in aceruloplasminemia (ceruloplasmin gene mutations) was also discussed.

Animals↗

PubMed2001

Human papillomavirus type 16 is an important infectious factor in the high incidence of esophageal cancer in Anyang area of China.

To investigate the potential role of human papillomavirus (HPV) infection in the pathogenesis of esophageal carcinomas in the Anyang area of China, we have evaluated specimens collected by balloon cytology examination from volunteers in two regions with significantly different incidences of esophageal carcinoma. 138 donors were from a village in a county with an esophageal carcinoma (EC) age-adjusted mortality rate of 132x10(5), the remaining 68 were resident in a second village from another county with an EC mortality rate of 52x10(5). Specimens were evaluated using both polymerase chain reaction (PCR) amplification and in situ hybridization (ISH) protocols. PCR results showed that the prevalence of the human papillomavirus type 16 (HPV-16) E6 gene in the high incidence area was 1.9-fold higher than that of the low incidence area (72 and 37%, respectively, P < 0.01). Moreover, the positive rate corresponded with pathology grade. Similar results were obtained with the HPV-16 E7 gene. As the cells undergoing cytopathological progress, the HPV-16 E6 positive rate was increased, in both villages. In contrast to HPV-16 E6 and E7, detection of the HPV L1 gene was consistently lower, and its prevalence decreased with increasing dysplasia grades (P < 0.05). By ISH analyses, the expression rate of HPV-16 E6 in the specimens collected from the high incidence area was 2.2-fold higher than those from the low incidence area (49 versus 22%, respectively; P < 0.05), and transcription of the E6 gene paralleled cytopathology. HPV-18 was also detected in 17 and 15% of the specimens from the high and low incidence areas, respectively, but most of these samples were also simultaneously HVP-16 positive. These results suggest that HVP-16 plays a causative role in the high incidence of esophageal cancer in the Anyang region of CHINA:

China↗

PubMed2001

Increased nitric oxide is one of the causes of changes of iron metabolism in strenuously exercised rats.

This study was carried out to investigate the possible role of increased nitric oxide (NO) production in the development of the low iron status in strenuously exercised rats. Female Sprague-Dawley rats were randomly assigned to four groups: sedentary (S1), sedentary + nitro-L-arginine methyl ester (L-NAME; S2), exercise (E1), and exercise + L-NAME (E2). Animals in the E1 and E2 groups swam for 2 h/day for 3 mo. L-NAME in the drinking water (1 mg/ml) was administrated to rats in the S2 and E2 groups for the same period. At the end of third month, hematological indexes and nitrite and nitrate (NOx) contents in the plasma and non-heme iron and NOx levels in the liver, spleen, and bone marrow cells were measured. Three months of exercise induced a significant increase in NOx content and a decrease in iron level both in plasma and tissues. Treatment with L-NAME, an inhibitor of NO synthase (NOS), led to a significant decrease in NOx and an increase in iron level both in plasma and tissues in the exercised rats. The E2 group had a significantly lower NOx content as well as a higher iron level both in plasma and tissues than the E1 group. However, the iron contents in the plasma and tissues of the E2 group were still significantly lower than those found in S1. No difference was found in NOx levels between E2 and S1. These findings showed that exercise was associated with elevation in NOx and reduction in iron in plasma and the tissues. Treatment with L-NAME was able to completely inhibit the effect of exercise on NOx as well as partly recover the decreased iron contents in plasma and tissues resulting from exercise. This suggests that the increased production of NO might be one of the causes of the lower iron status in exercised rats.

Animals↗

PubMed2001

Multinuclear magnetic resonance spectroscopy studies of brain purines in major depression.

OBJECTIVE: Studies of depressed adults have shown abnormalities in cerebral energy metabolism, as noted by low brain levels of nucleoside triphosphate (NTP), which primarily represents adenosine triphosphate (ATP). This study was undertaken to determine whether proton magnetic resonance spectroscopy (1H MRS) measures of the low-field purine resonance, which arises primarily from adenosine phosphates, can be used to assess abnormalities in cerebral purine metabolism in depressed adults. METHOD: Data from 1H MRS and phosphorus-31 (31P) MRS were acquired for depressed and nondepressed comparison subjects. Intensities of the purine resonance, by 1H MRS (7.5-8.5 ppm), and of NTP, by 31P MRS, were determined. RESULTS: Purine resonance intensities did not differ on average between depressed patients and comparison subjects. However, purine levels were approximately 30% lower in female depressed subjects who subsequently responded to fluoxetine treatment than in those who did not respond. Beta-NTP was lower by 21% in responders than in nonresponders and was correlated with purine levels for the depressed subjects. CONCLUSIONS: Brain purine levels are low in female depressed patients who respond to treatment with fluoxetine, suggesting that response to treatment might be predicted by using 1H MRS. These observations also suggest that agents that increase brain adenosine levels may have antidepressant efficacy.

Adenosine Triphosphate↗

PubMed2001

Skin reflectance in the Han Chinese and Tibetan populations.

Genetic and environmental factors are involved in the determination of skin pigmentation in humans. With the recent development of statistical and genetic tools in mapping complex traits in humans, it is becoming feasible to utilize such methods in identifying genes involved in skin pigmentation. Furthermore, the use of new portable reflectance spectroscopy instruments such as the Photovolt ColorWalk colorimeter allows researchers to measure skin reflectance of a large number of subjects with ease and accuracy. We used a new portable instrument (Photovolt ColorWalk) to study the skin reflectance of 372 Han Chinese and 274 Tibetan individuals to establish background reflectance measurements of unexposed skin of the inner upper arm in these two populations. In addition, we explored the effect of various factors such as age and gender on skin reflectance.

Adolescent↗

PubMed2001

Determination of menadione sodium bisulfite in pharmaceutical preparations by flow-injection on-line photochemical spectrofluorometry.

A flow-injection on-line photochemical spectrofluorometry (FI-PF) was developed for the determination of menadione sodium bisulfite (MSB) using acetone and sodium sulfite as sensitizing reagents. An injected sample band carried by a water stream was on-line merged with a mixed NaOH, Na2SO3 and acetone solution in a "T" connector. It was then driven to pass a knotted PTFE photochemical reactor (0.5 mm i.d. x 200 cm, KR) that was freely coiled around a 6-W low-pressure mercury lamp. While passing the KR, MSB was derived into an intensively fluorescent compound that was on-line delivered into a flow-through cell and detected therein at an emission wavelength of 459 nm and an excitation wavelength of 336 nm. Under optimized conditions a detection limit of 0.38 microg l(-1) was achieved at a sampling rate of 90 h(-1). Eleven determinations of 0.5 mg l(-1) and 0.05 mg l(-1) MSB standard solution gave RSDs of 0.75% and 1.3%, respectively. The calibration curve was linear in the MSB concentration range 0.005-1.5 mg l(-1). The proposed method was successfully applied to assay the MSB content in MSB injection.

Flow Injection Analysis↗

PubMed2001

Obliterative muscularization of the small bowel submucosa in Crohn disease: a possible mechanism of small bowel obstruction.

CONTEXT: The pathology of small bowel obstruction in Crohn disease has not been studied extensively. Stricture formation has been attributed mainly to fibrosis, although muscularization of the submucosa has been discussed previously. OBJECTIVE: To identify additional pathologic changes in Crohn disease that could be involved in the formation of strictures. DESIGN: We reviewed 50 ileal resections from patients with Crohn disease. The histopathologic slides were reviewed initially without knowledge of the macroscopic or clinical findings. We identified an unusual muscular proliferation that we refer to as obliterative muscularization of the submucosa, defined as a thick and continuous muscle layer from the mucosal base to the muscularis propria that is at least 1 cm in length. Subsequently, histopathologic findings were correlated with macroscopic and clinical findings. RESULTS: Obliterative muscularization of the submucosa was present in 14 specimens, and in 11 of these 14 it was topographically restricted to strictures. Submucosal fibrosis was observed in sections from adjacent regions. Obliterative muscularization of the submucosa, including thick-walled vessels and hyperplastic nerves but not prominent scarring, was more common in specimens with strictures; the difference was statistically significant (P <.001). CONCLUSIONS: Obliterative muscularization of the submucosa may be pathogenetically involved in the formation of strictures either directly by causing a sustained spasm, or indirectly by minimizing the vasoprotective role of the submucosa, impairing repair and enhancing scarring.

Adolescent↗

PubMed2001

[The effect of bombesin on cyclin D1/CDK4 of immortalized human gastric epithelial cell line].

OBJECTIVE: To investigate the regulatory effect of bombesin on the growth of immortalized human gastric epithelial cell line GES-1, as well as on the cell cycle-regulating elements cyclin D1 and CDK4. METHODS: GES-1 cells were treated with bombesin, alone or together with an bombesin antagonist. The growth effect was evaluated by MTT method, cyclin D1 expression by flow cytometry, CDK4 expression by Western blot plus enhanced chemoluminescence and CDK4 activity by immunoprecipitation with antibody-coated Sepharose beads. RESULTS: Bombesin at 10(-7) mol/L significantly stimulated the growth of GES-1 cells, increased cyclin D1 expression which was inhibited by bombesin antagonist. Bombesin also increased CDK4 protein expression and CDK4 activity. CONCLUSION: In an immortalized human gastric epithelial cell line, bombesin promotes cell cycle progression via an increase in the expression of cyclin D1/CDK4 and CDK4 activity.

Bombesin↗

PubMed2001

[Localization and analysis of 1A6 gene by dual-color fluorescence in situ hybridization on gastric carcinoma tissue and tumor cell lines].

OBJECTIVE: To locate 1A6 gene on the chromosome and study its copy number by dual-color fluorescence in situ hybridization (FISH) on three tumor cell lines and 22 gastric tumors patients. METHODS: The single-color FISH of small size biotin-labeled cDNA cloned in plasmid was used to locate the 1A6 gene on one of the chromosomes in C group. Genomic DNA of 1A6 gene was screened by polymerase chain reaction (PCR) in PAC library according to the sequence. The florenscence of green and orange was incorporated into the target gene-1A6 cloned in PAC and chromosome-12-specific alpha-satellite repeat DNA by nick translation, followed by dual-color FISH. 1A6 gene was located in the metaphase chromosome of the normal peripheral lymphocytes. 1A6 gene and chromosome 12 copy numbers were analyzed on touch slide of gastric cancer tissue and cell lines. RESULTS: 1A6 gene was located in 12q23.2-23.3. The chromosome 12/1A6 signal ratio was 0.96-1.01 in breast, ovarian and gastric cancer cell lines. The ratio was 0.93-1.11 in gastric cancer tissue touch slides. The number of chromosome 12 is disomic (87.7%), triploid (7.4%) in BMI cell line; multisomic(100%), including pentasomic (67.6%) in SKOV3; the multisomic (83.1%), including trisomic (71%) in SGC823. There are highly disomic rate in 86. 4% (19/22) of patients. CONCLUSION: 1A6 gene is in 12q23.2-23.3. Neither 1A6 amplification nor deletion in gastric cancer tissue and three cell lines was found. Further study is needed for the understanding of chromosome 12 copy number variation in different cancer cell lines.

Chromosome Mapping↗

PubMed2001

[Clinical study of P-gp, and bcl-2 protein expression in non-Hodgkin's lymphomas patients].

OBJECTIVE: To investigate the relationship between the expression of P-gp, P26-bcl-2 and the prognosis in intermediate and high grade non-Hodgkin's lymphomas (NHL). METHODS: Sixty cases of intermediate and high grade NHL were retrospectively reviewed using immunohistochemical method. All patients were received CHOP chemotherapy over 4 courses. RESULTS: P-gp was identified in 15 and P26-bcl-2 in 25 cases. The 3-year survival rates for patients with P26-bcl-2 (+) and P26-bcl-2 (-) were 37.64% and 76.80%, respectively (P < 0.005), and for patients with both positive P-gp and P26-bcl-2 and both negative were 15.38% and 48.48%, respectively (P = 0.038). CONCLUSIONS: There is direct relationship between the P-gp, P26-bcl-2 protein expression and the prognosis in intermediate and high grade non-Hodgkin's lymphoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[Construction of the full-length cDNA clone of Chinese virulent strain--F114].

Seven subclones covered the complete genome of classical swine fever virus Chinese virulent strain F114 were obtained by reverse transcription PCR. The complete nucleotide sequence of the genome of strain F114 was determined by sequencing. The cDNA fragments were then assembled and inserted downstream of a T7 promoter in pBluescript II sk+ plasmid vector to obtain the full-length cD-NA clone sk-12297. Homology comparison of the nucleotide and amino acid sequence of strain F114 with the known sequences of HCLV, Brescia and Alfort showed 95.70%, 96.80%, 86.03% identity in nucleotide and 97.41%, 98.54%, 93.33% identity in amino acid respectively.

Animals↗