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Biomedical subjects

W Ding

Publications and source records attributed to W Ding.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Influence of functional groups of huatanyuxin decoction on Ca2+ transmembrane influx in rat aorta].

OBJECTIVE: To study the Ca2+ antagonistic effect of functional groups of Huatanyuxin decoction. METHOD: The 45Ca transmembrane influx technique was used to measure the Ca2+ blocking effect of leak, receptor-operated Ca2+ channel (ROC) and potential-dependent Ca2+ channel (PDC) in rat aorta. RESULT: ROC and PDC could be blocked when the complex prescription was used at concentrations of 0.5-5 mg/ml. Among the functional groups, Huoxue group (activating blood) and Xinqi group (promoting and normalizing flow of vital energy) showed better Ca2+ antagonistic effect. CONCLUSION: The mechanism of therapeutic effect of Huatanyuxin decoction may be related to its Ca2+ blocking effect similar to verapamil.

Animals↗
PubMed1999

[Determination of 14 elements in chromium-rich brewer's yeast by ICP-AES].

An ICP-AES method was established for the determination of 14 elements in chromium-rich and normal brewer's yeast. The RSDs of two standard reference materials were 0. 5%-3.2% and 0.4%-3.4%, respectively. The results showed that chromium contents could affect the concentrations of other elements in chromium-rich brewer's yeast. The concentrations of K, Mn, P, V, Mg and Ca in chromium-rich brewer's yeast were significantly lower than those in normal brewer's yeast.

Chromium↗
PubMed1998

[Effects of Trp64Arg mutation in the beta 3-adrenergic receptor gene on body fat, plasma glucose level, lipid profile, insulin secretion and action in Chinese].

OBJECTIVE: To ascertain the association of the Trp64Arg mutation in the beta 3-adrenergic receptor (ADRB3) gene with the total body fat and fat distribution, plasma glucose level, lipid profile, insulin secretion and action in Chinese. METHODS: Genotyping of the Trp64Arg mutation in the ADRB3 gene as well as measurment of clinical variables body mass index(BMI), percent of desirable weight(PDW), area of regional adipose tissue depots, fasting lipid profile, and also, plasma glucose, insulin, C-peptide, free fatty acids levels before and after glucose challenge and blood pressure were performed in 308 Chinese, of whom, 161 were nondiabetics and 147, type 2 diabetic subjects. RESULTS: (1) The frequency of Arg64 allele of ADRB3 gene in Chinese was similar to that in Japanese but slightly higher than that in Caucasians. (2) No association of any of the clinical varaibles with Trp64Arg mutation was observed in nondiabetics. (3) The Trp64Arg mutation in the ADRB3 gene was associated with BMI(P=0.019), PDW(P=0.001) and waist circumference (P=0.045) in type 2 diabetic subjects. In female diabetic subjects, more significant association with BMI(P=0.001), PDW(P=0.001), waist circumference(P=0.023), and also, association with abdominal and femoral subcutaneous fat area(P=0.032 and P=0.023) were observed. The frequencies of Arg64 allele were 21%, 14% and 4% in female diabetics with obesity, over-weight and normal-weight respectively (P=0.026). Logistic regression analysis showed that BMI was the only independent clinical variable related to the Trp64Arg mutation in the ADRB3 gene (P=0.0027). CONCLUSION: The Trp64Arg mutation in ADRB3 gene contributes to the variation of total body fat in Chinese type 2 diabetic subjects.

Adipose Tissue↗
PubMed1998

Leukemic cellular retinoic acid resistance and missense mutations in the PML-RARalpha fusion gene after relapse of acute promyelocytic leukemia from treatment with all-trans retinoic acid and intensive chemotherapy.

This study evaluated whether relapse of acute promyelocytic leukemia (APL) patients from clinical remissions achieved and/or maintained with all-trans retinoic acid (RA) in combination with intensive chemotherapy is associated with leukemic cellular resistance to RA and with alterations in the PML-RARalpha fusion gene. We studied matched pretreatment and relapse specimens from 12 patients who received variable amounts of RA, primarily in nonconcurrent combination with daunorubicin and cytarabine (DA) on Eastern Cooperative Oncology Group (ECOG) protocol E2491, and from 8 patients who received DA only on protocol E2491. Of 10 RA-treated patients evaluable for a change in APL cell sensitivity to RA-induced differentiation in vitro, 8 showed diminished sensitivity at relapse, whereas, of 6 evaluable patients treated with DA alone, only 1 had marginally reduced sensitivity. From analysis of sequences encoding the principal functional domains of the PML and RARalpha portions of PML-RARalpha, we found missense mutations in relapse specimens from 3 of 12 RA-treated patients and 0 of 8 DA-treated patients. All 3 mutations were located in the ligand binding domain (LBD) of the RARalpha region of PML-RARalpha. Relative to normal RARalpha1, the mutations were Leu290Val, Arg394Trp, and Met413Thr. All pretreatment analyses were normal except for a C to T base change in the 3'-untranslated (UT) region of 1 patient that was also present after relapse from DA therapy. No mutations were detected in the corresponding sequences of the normal RARalpha or PML (partial) alleles. Minor additional PML-RARalpha isoforms encoding truncated PML proteins were detected in 2 cases. We conclude that APL cellular resistance occurs with high incidence after relapse from RA + DA therapy administered in a nonconcurrent manner and that mutations in the RARalpha region of the PML-RARalpha gene are present in and likely mechanistically involved in RA resistance in a subset of these cases.

Adolescent↗
PubMed1998

Capillary electrophoresis of anions at high salt concentrations.

It is commonly thought that even a moderately high ionic concentration in the background electrolyte (BGE) would lead to Joule heating and serious peak distortion. However, we obtained very satisfactory separations of both inorganic and organic anions in electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. Samples containing a 0.5 M concentration of a salt can be analyzed directly by making the BGE concentration of the same salt even higher to obtain electrostacking. The temperature in the center of the capillary was calculated to be 49 degrees C when the current is at its maximum of 280 microA. The effect of various salts on electrophoretic and electroosmotic mobility is discussed. Several examples are given of capillary electrophoresis under high-salt conditions.

Anions↗
PubMed1998

Use of the enriched stable isotope Cr-50 as a tracer to study the metabolism of chromium (III) in normal and diabetic rats.

The activable enriched stable isotope Cr-50 compound Cr2O3 was used as a tracer to study the metabolism of chromium(III) [CR(III)] intragastrically administered in normal and diabetic rats. The comparison of absorption, distribution, and excretion in organs and tissues of the two groups do not show much alteration, but some differences exist indeed. The contents of 51Cr radioactivity of the diabetic rats appear to be of higher retention than in most studied organisms. The urinary 51Cr excretion of diabetics is significantly higher than that of normal rats. Therefore, a conclusion can be drawn that the insulin-dependent rats generally absorb and excrete more chromium (Cr) than the normal rats.

Absorption↗
PubMed1998

Serum and urine chromium concentrations in elderly diabetics.

The serum and urine chromium concentrations of 57 diabetics and 55 normal fasting subjects were determined by atomic absorption spectrometry (AAS). Our results indicate that the chromium concentration ranges of serum and urine for diabetics are 0.22-0.36 and 4.54-5.90 microg/L, respectively, significantly lower than 0.66-0.84 7.80-9.68 microg/L for the normal (P<0.001), which implies that the elderly diabetics probably lack chromium. Further, it was found that the urine chromium level of the female diabetics was substantially higher than that of the male in the same age group (P<0.01), whereas the serum chromium level was almost the same. However, the urine chromium concentration increases with aging, no matter who the diabetics or the controls are. The serum chromium concentrations of the 24 cases patients with 2-h oral glucose tolerance test (OGTT) were significantly lower than that of those with empty stomach, whereas the urine chromium exhibits a contrary tendency. Our data indicate that the chromium lost and excreted from human body increases with aging and is related to the diabetics. Thus, it is recommended to supplement a certain amount of chromium to the elderly diabetics according to their nutritional level.

Aged↗
PubMed1998

Heparin oligosaccharides that pass the blood-brain barrier inhibit beta-amyloid precursor protein secretion and heparin binding to beta-amyloid peptide.

We have previously demonstrated that full-length heparin stimulates the synthesis and secretion of beta-amyloid precursor protein (APP) through an amyloidogenic pathway in neuroblastoma cells. In the present study, heparin was chemically depolymerized, and the effect of low-molecular-weight (LMW) heparin on APP secretion was investigated. In contrast to full-length heparin, LMW heparin had no significant effect on APP secretion. However, LMW heparin fragments, especially heparin disaccharides, were able to inhibit efficiently the stimulatory effect of heparin on APP secretion. LMW heparin derivatives also inhibit the binding of heparin to the beta-amyloid peptide (1-28). Using an in vitro model, we further demonstrated the passage of LMW heparin derivatives through the blood-brain barrier. This study suggests that LMW heparin derivatives or analogues may be effective as therapeutic agents to prevent or slow the process of amyloidogenesis in Alzheimer's disease.

Amyloid beta-Protein Precursor↗
PubMed1998

Localization of the ROMK potassium channel to the apical membrane of distal nephron in rat kidney.

BACKGROUND: The apical potassium (K+) channels mediate K+ recycling in thick ascending limb (TAL) and K+ secretion in cortical collecting duct (CCD). Recently, the cDNAs for a family of renal K+ channels, ROMK1, -2 and -3, were identified. Based on the biophysical properties and mRNA distribution, it is believed that these ROMK cDNAs encode the apical K+ channels of TAL and CCD. However, the information for cellular and subcellular localization of the ROMK proteins in these tubules is still not available. METHODS: Paraffin or frozen kidney sections from adult Sprague-Dawley rats were stained by polyclonal antibodies against the N- and C-terminal domain of ROMK. Immunoreactive staining was visualized by color development from horseradish peroxidase reaction. Membrane homogenates from kidney were analyzed by Western blot analysis. RESULTS: The polyclonal antibodies against cytoplasmic epitope of ROMK recognized a approximately 42 kD protein in the membrane homogenates from kidney, but not from liver. Staining by immunocytochemistry revealed that ROMK channels were localized to the apical membranes of the distal nephron in cortex and outer medulla, including thick ascending limb and collecting tubule. ROMK staining was absent in glomerulus, proximal tubule and inner medulla. Double staining of the tissue section with both ROMK-specific and H+-ATPase-specific antibodies revealed labeling of ROMK in the principal cells of the collecting tubules. CONCLUSIONS: These results further strengthen the idea that ROMK channels play important roles in the recycling of K+ in TAL and the secretion of K+ in CCD.

Animals↗
PubMed1998

Inhibition of spontaneous formation of lung tumors and rhabdomyosarcomas in A/J mice by black and green tea.

We investigated the effects of black tea (BT) and green tea (GT) infusion on the spontaneous formation of lung tumors and rhabdomyosarcomas in A/J mice. Female A/J mice, 6 weeks of age, were allocated into five groups (50 per group) and were given the following as the sole source of drinking fluid: (i) deionized water (control group), (ii) 0.5% BT, (iii) 1% BT, (iv) 2% BT and (v) 1% GT. After 60 weeks, the mice were killed by decapitation. Lung tumor incidence, multiplicity and volume were significantly lower in the 2% BT group as compared with the controls (27 versus 52%, 0.33 versus 0.72 tumors/mouse and 4.27 versus 38.3 mm3, respectively). The 1% GT group had significantly lower lung tumor multiplicity (0.41/mouse), while the 1% BT group had significantly decreased tumor volume (7.17 mm3). Rhabdomyosarcomas were found in 34% of the mice in the control group, and both the 1 and 2% BT groups had significantly lower incidences at 13 and 14%, respectively. The mice in the 2% BT group weighed 16% less than those in the control group, although they consumed more food than the control group. The other tea-consuming groups also weighed less than the control group (7.8-11%) while consuming more food and fluid. In a separate experiment, similar carcinogenesis inhibition was also observed in female A/J mice that were given 0.6% and then 0.3% instant black tea for 52 weeks. These results demonstrate the inhibitory activity of BT against the spontaneous formation of lung tumors and rhabdomyosarcomas in mice.

Animals↗
PubMed1998

[Hepatotoxicity and formation of reactive oxygen species induced by microcystis aeruginosa toxin].

OBJECTIVE: To study hepatotoxicity of Microsystis aeruginosa toxin (microcystin) and its prevention. METHODS: Cytotoxicity and the formation of reactive oxygen species (ROS) of microcystin extracted water bloom were studied in rat liver cells of primary culture. RESULTS: It was found that the release of lactic dehydrogenase (LDH) increased with a time- and dose-dependent pattern in the liver cells treated with microcystin, and a time- dependent formation of ROS also increased simultaneously. The antioxidant, desferrioxamine, could decrease the release of LDH and the formation of ROS in the liver cells treated with microcystin. CONCLUSION: Microcystin has obvious hepatotoxicity and the formation of ROS may play a certain role in its toxic effect on the rat liver cells.

Animals↗
PubMed1998

[Effects of nitrogen form on American ginseng leaf blight].

The effects of two nitrogen forms(NO3-N and NH4-N) on American ginseng leaf blight were studied using sand culture method. The results indicated that American ginseng leaf blight caused by Alternaria panax was reduced with NO3-N, while increased with NH4-N.

Alternaria↗
PubMed1998

Regulation of the insulin signalling pathway by cellular protein-tyrosine phosphatases.

Protein-tyrosine phosphatases (PTPases) have been implicated in the physiological regulation of the insulin signalling pathway. In cellular and molecular studies, the transmembrane, receptor-type PTPase LAR and the intracellular, non-receptor enzyme PTP1B have been shown to have a direct impact on insulin action in intact cell models. Since insulin signalling can be enhanced by reducing the abundance or activity of specific PTPases, pharmaceutical agents directed at blocking the interaction between individual PTPases and the insulin receptor may have potential clinical relevance to the treatment of insulin-resistant states such as obesity and Type II diabetes mellitus.

Animals↗
PubMed1997

Heparin promotes beta-secretase cleavage of the Alzheimer's amyloid precursor protein.

In Alzheimer's disease, abnormal processing of the amyloid precursor protein (APP) is thought to play an important role in amyloid deposition. We investigated the effect of heparin, a highly sulfated glycosaminoglycan related to heparan sulfate, on the secretion of the beta-secretase cleavage product of APP (sAPP beta) in a human neuroblastoma cell line. Heparin induced an increase in the secretion of total APP, and an even greater relative increase in the secretion of sAPP beta. The effect on sAPP beta was specific to heparin. These data support the hypothesis that highly sulfated heparan sulfate proteoglycans may promote amyloidogenic pathways of APP metabolism.

Alzheimer Disease↗
PubMed1997

Black tea constituents, theaflavins, inhibit 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice.

The present study investigated the inhibitory activity against lung tumorigenesis by a group of characteristic black tea polyphenols, theaflavins. In a short-term study, female A/J mice were treated with a single dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK; 103 mg/kg b.w., i.p.) on day 0, and 0.1 and 0.3% theaflavins were administered as the sole source of drinking fluid starting 24 h after NNK treatment. The proliferation index of the lung tissues was measured by the incorporation of bromodeoxyuridine (BrdU) immunohistochemically. The highest NNK-induced proliferation rate of bronchiolar cells, observed on day 5, was significantly decreased by 0.3% theaflavins (proliferation index, 1.51 +/- 0.08 versus 2.35 +/- 0.16). In a long-term lung tumorigenesis study, pulmonary adenomas were observed in 100% (30/30) of the mice at week 16 after NNK treatment. Administration of theaflavins (0.1%) as the sole source of drinking fluid, starting 2 days after the NNK treatment until the termination of the experiment, significantly reduced the tumor multiplicity and volume by 23% (8.5 +/- 0.6 versus 6.5 +/- 0.6 tumors/mouse) and 34% (0.08 versus 0.05 mm3 per tumor), respectively. The proliferation index in lung adenomas was also significantly inhibited by theaflavins. The present work demonstrates the inhibitory action of theaflavins against NNK-induced pulmonary hyperproliferation and tumorigenesis.

Animals↗
PubMed1997

[Relationship between the site of coronary artery occlusion and degree of hemodynamic abnormality of right ventricular myocardial infarction].

Twenty one patients with acute inferior myocardial infarction underwent hemodynamic monitoring and coronary angiography study. 16 cases were diagnosed as having right ventricular myocardial infarction (RVMI) by the hemodynamic characteristics of RVMI and 5 cases no RVMI. In the 16 patients with RVMI, 15 (93.8%) had proximal or middle segment occlusion of right coronary artery (RCA) and the remaining one (6.3%) was caused by occlusion of left circumflex with no distal segment occlusion of RCA. According to the ratio of MRAP/PCWP, we divided the hemodynamic abnormality into two subgroups: MRAP/PCWP > or = 0.8 was considered severe and MRAP/PCWP 0.65-< 0.8 mild. In the 16 patients with RVMI, 10 cases were severe and 6 cases mild. The site of coronary artery occlusion in the severe group were 4/10 (40%) at proximal segmet of RCA and 5/10 (50%) at middle segmet of RCA and the remaining one case the site of occlusion was in circumflex, while in the mild group, 3/6 (50%) of the cases had occlusion at the proximal segment of RCA and 3/6 (50%) at middle segment of RCA. The results of this study showed that inferior myocardial infarction caused by proximal or middle segment occlusion of RCA might be accompanied by RVMI, but there was no relationship between the degree of hemodynamic abnormality and the site of RCA occlusion.

Adult↗
PubMed1997

[An analysis on 30 cases of orbital schwannomas].

OBJECTIVE: To study isolated orbital schwannomas confirmed histopathologically in our hospital between 1985 and 1994. METHODS: The clinical features, diagnosis and treatment of 30 cases with the tumor were retrospectively studied. The postoperative complications and clinical recurrences after different surgical approaches were compared. RESULTS: Isolated orbital schwannoma occurs most commonly at the age of 20-40. The sex incidence is similar. Most of the patients complained of proptosis, some of them were accompanied by blurred vision, ocular pain, restricted ocular movement, etc. The tumors were resected surgically. In comparison with pre-operative visual acuity, the postoperative visual acuity was worse in 8 cases (26.7%), similar in 13 cases (43.3%), and improved in 9 cases (30.0%). There were early ptosis of the eyelid in 8 cases (26.7%) and restricted eye movement in 11 cases (36.7%). In 1.5-10 years of follow-up, clinical recurrences in 5 cases, one malignant and four benign, were seen. Most of the ptosis and restricted eye movement recovered after 3-6 months. CONCLUSION: According to the location of the tumor, the best surgical approach should be selected.

Adolescent↗