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Biomedical subjects

L Bian

Publications and source records attributed to L Bian.

18 recordsLinked to original sources
PubMed2001

Distinguishing cochlear pathophysiology in 4-aminopyridine and furosemide treated ears using a nonlinear systems identification technique.

To test the adequacy of physiologic indices derived from a third-order polynomial model quantifying cochlear mechano-electric transduction (MET), 24 Mongolian gerbils were exposed to either 250-mM glucose (control), 150-mM 4-aminopyridine (4-AP), or 30-mM furosemide solutions applied to the round window (RW) membrane. The cochlear microphonic (CM) was recorded from the RW in response to 68- and 88-dB SPL Gaussian noise. A nonlinear systems identification technique (NLID) provided the frequency-domain parameters and physiologic indices of the polynomial model of MET. The control group showed no change in both compound action potential (CAP) thresholds and CM. Exposure to 4-AP and furosemide resulted in a similar elevation in CAP thresholds and a reduction in CM. However, the polynomial model of MET showed different changes. The operating point, slope, and symmetry of the MET function, the polynomial model parameters, and related nonlinear coherences differed between the experimental groups. It is concluded that the NLID technique is sensitive and specific to alterations in the cochlear physiology.

4-Aminopyridine↗
PubMed2001

Localization of EP(1) and FP receptors in human ocular tissues by in situ hybridization.

PURPOSE: To examine the expression and localization of EP(1) and FP receptor mRNAs in normal human ocular tissues by in situ hybridization. METHODS: Digoxigenin-labeled human EP(1) and FP receptor antisense and sense riboprobes were used for in situ hybridization on paraffin sections of normal human eye tissue. RESULTS: In situ hybridization revealed the presence of high levels of both EP(1) and FP receptor mRNA transcripts in the blood vessels of iris, ciliary body, and choroid. Both the endothelial and smooth muscle cells of blood vessels demonstrated intense hybridization signals corresponding to EP(1) receptor mRNA transcript. EP(1) receptor hybridization signals were present in all the muscle fibers of the ciliary body. In the retina, hybridization signals for EP(1) receptors were observed in photoreceptors and both nuclear layers and in ganglion cells. The hybridization signals corresponding to FP receptor transcript were similar to those of EP(1) receptors in the iris tissues. In the ciliary muscle, FP receptor mRNA transcript was predominantly present in the circular muscle and in the collagenous connective tissues; no hybridization signal for this receptor was observed in the retina. CONCLUSIONS: The wide distribution of EP(1) and FP receptor mRNAs in human ocular tissues appears to be localized in the functional sites of the respective receptor agonists. Selective localization of FP receptor mRNA in the circular muscles and collagenous connective tissues of the ciliary body suggests their involvement in the increased uveoscleral outflow of aqueous humor by PGF(2alpha).

Blotting, Northern↗
PubMed2001

[Relationship between the expression of Bax and apoptosis induced by hyperthermia in BcaCD885 cells].

OBJECTIVE: This study aimed to investigate the role of Bax gene in apoptosis induced by hyperthermia in BcaCD885 cells. METHODS: After inducing apoptosis through hyperthermia, the expression of Bax protein and mRNA were examined with FCM antibody analysis and RT-PCR technique respectively. RESULTS: Up regulation of Bax protein was noted after hyperthermia. The correlation coefficient r between the apoptotic rate and the expression Bax protein was 0.9240. The expression of Bax mRNA was also raised after hyperthermia. CONCLUSION: Hyperthermia acting as an external signal may up-regulates expression of Bax gene and then induces apoptosis in BcaCD885 cells.

Apoptosis↗
PubMed2001

[Determination of total, soluble and insoluble dietary fiber in foods by enzymatic-gravimetric method].

For studying the contents of dietary fiber in general foods and functional foods, a enzymatic-gravimetric method recommended by AOAC was established in our laboratory. The method for the determination of total, soluble and insoluble dietary fiber in foods and functional foods could be used for many other kind of foods. The relative standard deviations (RSD) of reproducibility between-run and within-run were 2.04%-7.85%, 3.42%-55.23% respectively. The repeatability of the methods was good, and the methods are suitable for many foods.

Dietary Fiber↗
PubMed2000

The prevalence of lactase deficiency and lactose intolerance in Chinese children of different ages.

OBJECTIVE: To determine lactose metabolism and lactase activity in Chinese children of different ages, prevalence of lactase deficiency (LD), and lactose intolerance (LI). METHODS: All 1168 healthy subjects between 3 and 13 years were recruited from schools in four large cities in China. They were screened by a 25 g lactose tolerance test. Some subjects were challenged with 50 g milk powder on different days. Both indicators, the expiratory H2 concentration and intolerance symptoms, were analyzed. RESULTS: LD occurred in 38.5% of children in the 3-5 year age group, and 87% of the 7-8 year and 11-13 year old groups. The age of occurrence for LD may be at 7-8 years among Chinese children. The prevalence of LI among Chinese children was 12.2% at age 3-5 years, 33.1% at age 7-8 years, and 30.5% at age 11-13 years, respectively. CONCLUSION: The results demonstrate that LD is very common in Chinese children from these four cities. LD and LI have a dose dependent response: lactose absorption and symptoms are based on lactase activity. The relationship between breast feeding history (or the history of cow milk intake) and lactase activity among Chinese children has not been established.

Adolescent↗
PubMed2000

[Ultrasonically guided radio-frequency ablation of liver tumors with a clustered electrode: a report of 100 cases].

OBJECTIVE: To evaluate the efficacy of ultrasonically guided radio-frequency (RF) thermal ablation of liver tumors with a clustered electrode. METHODS: Clinical records of 100 consecutive patients who underwent RF tissue ablation 120 times were analysed. Image data, tumor size, clinic manifestation, and AFP value before and after the procedure were compared. RESULTS: A hundred cases at 10 days, thirty at 30 days, ten at 60 days after the procedure were subjected to color ultrasonography and CT scans, respectively. The tumor size decreased by 20% at 10 days in 70% patients, decreased by 30% at 30 days in 80% patients, decreased by 50% at 60 days in 3 patients. AFP value decreased in 50% of patients, no operative death was noted, and the rate of operative complication was 23% after ablation. CONCLUSION: Ultrasound guided RF thermal ablation of hepatic tumors is safe, applicable and effective.

Adolescent↗
PubMed1999

[Effect of exogenous lactase on the absorption of lactose and its intolerance symptoms].

The objective of this study was to evaluate the effects of lactase on lactose malabsorption and its intolerance symptoms, as well as the available way to improve lactose absorption. Healthy adults with a history of lactose intolerance were screened by 25 g lactose tolerance test. The individuals with higher H2 expired and/or lactose intolerance symptoms were selected as the subjects. Subjects were challenged twice with "400 ml low fat milk" and "400 ml low fat milk + 9000Fcc lactase" separately in 3 days interval. The breath H2 concentration and intolerance symptoms were tested in 4 hours after the challenge. The results showed that exogenous lactase can significantly decrease the incidence of lactose malabsorption (the abnormal expiration of H2 decreased from 100% to 48.9%) and milk intolerance symptoms(from 51.1% to 13.3%). The results from this study demonstrate that lactose malabsorption and intolerance symptoms are resulted from the reduced enzyme activities of individuals, and the exogenous lactase can improve lactose absorption and intolerance symptoms. Lactose supplementation may be an available way to increase the dairy consumption and promote health of people.

Adolescent↗
PubMed1999

[Study on the incidence of lactose intolerance of children in China].

1168 healthy children of 3-13 years old were selected as subjects from Beijing, Shanghai, Guangzhou and Haerbin. Total subjects were challenged by 25 gram lactose test. The breath hydrogen was determined, the symptoms of lactose intolerance were recorded. The results showed that the incidences of lactase deficiency of children of 3-5, 7-8 and 11-13 years old were 38.5%, 87.6% and 87.8% respectively. The incidences of lactose intolerance were 12.3%, 33.2% and 30.5% respectively. Lactase activity decreasing of Chinese children occurred at the age of 7-8 years old, and the symptom of lactose intolerance depended on lactose dose. But, there still are 39%-41.7% children with lactose maldigestion and 14%-16% children with intolerance symptom, after taking 50 gram milk powder (12 g lactose). The relationship between lactase activity and milk intake was not found.

Adolescent↗
PubMed1999

Expression of sarco/endoplasmic reticular Ca(2+)-ATPase in human lens epithelial cells and cultured human lens epithelial B-3 cells.

PURPOSE: Sarco/Endoplasmic Reticulum Ca(2+ )-ATPase (SER-CAs) isoforms, SERCA2b (100Kd) and SERCA3 (97Kd), are co-expressed in some non-muscle tissues. Both types of SERCAs play important roles in Ca(2+) regulation in non-muscle tissues such as brain and platelets. We tested whether these two SERCAs are present in human lens epithelial cells, human lens epithelial B-3 cells (HLE B-3 cells) and rat lens epithelial cells providing a basis for further studies the role of SERCAs in cataract formation. METHODS: Lens epithelial cells from rat lens, human lens and cultured human lens epithelial B-3 cell line (HLE B-3) were used to extract mRNA and membrane proteins. Reverse transcription polymerase chain reaction (RT-PCR) was employed to detect SERCA3 and SERCA2b mRNA using SERCA2b and SERCA3 primers. Western blotting was used to detect SERCA3 and SERCA2b proteins using anti-SERCA2b and 3 antibodies. RESULTS: A 270 bp fragment was amplified with SERCA2b primers and a 186 bp fragment amplified with SERCA3 primer in human lens epithelial cells, human lens epithelial B-3 cells and rat lens epithelial cells. Both fragments are the expected SERCA2b and SERCA3 products. The sequences of these two fragments in human lens epithelial cells are 100% and 98% homologous to the published partial SERCA2b and SERCA3 mRNA sequence, respectively. The amino acid sequences translated from both PCR products are 100% homologous to the published SERCA2b and SERCA3 sequences in GeneBank. Western blotting confirmed that the expected 100 KDa and a 97 KDa proteins are recognized by anti-SERCA2b and anti-SERCA3 antibodies. CONCLUSION: Sarco/Endoplasmic Reticulum Ca(2+)-ATPase (SERCAs) isoforms 2b and 3 mRNAs are expressed in human lens epithelial cells, the cultured human lens epithelial B-3 cell line (HLE B-3) and rat lens epithelial cells. SERCA2b and SERCA3 may play an important role in the regulation of calcium homeostasis in lens epithelial cells.

Animals↗
PubMed1999

[Effect of food composition of mixed food on glycemic index].

UNLABELLED: In order to study the effect of protein, fat and dietary fiber on glycemic index(GI) of mixed food, the response of blood glucose and plasma insulin to nine diets with different components of food were tested by using glucose oxidase and radioimmunoassay. Glycemic index of 9 mixed foods show as follows, rice: 83.2 +/- 3.1, rice + stir fry pork: 72.0 +/- 14.0, rice + stir fry pork and celery: 57.1 +/- 11.2, rice + stir fry garlic sprout: 57.9 +/- 7.8, rice + stir fry garlic sprout and eggs: 62.8 +/- 16.7, steamed bread: 80.1 +/- 22.5, steamed bread + butter: 68.0 +/- 16.3, and steamed bread + beef: 49.4 +/- 22.8. Protein(P, beta 1 = -0.696, P < 0.01) and dietary fiber(Fi, beta 2 = -7.364, P < 0.01) can reduce the blood glucose response and were significantly related to GI. Fat also can inhibit the increment of blood glucose, but there is no significant relation with GI. When the co-ingestion of protein with carbohydrate, the serum insulin response increased greatly and the glycemic response reduced. The addition of fat can reduce the glycemic response without change in serum insulin. Dietary fiber can reduce the serum insulin response and inhibit the glycemic response. CONCLUSION: Protein and dietary fiber of mixed food could markedly affect the glycemic index of foods and reduced the blood glucose response.

Adult↗
PubMed1998

Mitogen-activated protein kinase is involved in epidermal-growth-factor-regulated protein phosphorylation in nuclear membranes isolated from JEG-3 human choriocarcinoma cells.

The treatment of highly purified nuclear membranes isolated from JEG-3 human choriocarcinoma cells with epidermal growth factor (EGF) resulted in an increase of the receptor autophosphorylation and the phosphorylation of several other proteins, including 44-kDa, 34-kDa and 24-kDa proteins, and a decrease in the phosphorylation of a 40-kDa protein. The kinetics of phosphorylation and the use of RG-13022, a selective inhibitor of EGF-receptor kinase activity, suggested that receptor activation was necessary for the phosphorylation response of the other proteins. Tyr was exclusively phosphorylated in the EGF receptor and 24-kDa proteins, Tyr and Thr were phosphorylated in the 44-kDa protein, and Ser was phosphorylated in the 34-kDa protein and dephosphorylated in the 40-kDa protein. The molecular size, Thr/Tyr phosphorylation, immunoprecipitation and enzymatic activity towards myelin basic protein suggested that the 44-kDa protein was a mitogen-activated protein (MAP) kinase. The EGF treatment not only increased phosphorylation but also catalytic activity of MAP kinase and these increases were prevented by the addition of RG-13022. In summary, this report demonstrates that target cell nuclei contain EGF receptors, which use the MAP kinase signaling pathway.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1998

Differentiation of cochlear pathophysiology in ears damaged by salicylate or a pure tone using a nonlinear systems identification technique.

Mongolian gerbils were exposed to either alpha-ketoglutarate, salicylate, or an 8-kHz pure tone. Cochlear microphonic (CM) was recorded from the round window in response to 68 and 88 dB SPL Gaussian noise. A nonlinear systems identification technique provided the frequency-domain parameters of a third-order polynomial model characterizing cochlear mechano-electric transduction (MET). A series of physiologic indices were derived from further exploration of the model. Exposure to the 8-kHz pure tone and round window application of salicylate resulted in different changes in the polynomial parameters and physiologic indices even though the threshold shifts were similar. A general reduction of CM magnitude was found after the tone exposure, and an increase at low-mid frequencies was demonstrated in the salicylate group especially at the lower signal level. The slope of the MET curve was reduced by the acoustic overstimulation. The root or the operating point of the MET was shifted in opposite directions after the two treatments. Sound-pressure levels that saturate MET expanded in the tone exposure group and narrowed in the salicylate group. The signal level also had effects on these indices.

Animals↗
PubMed1997

Characterizing cochlear mechano-electric transduction in ears damaged with pure tones.

Cochlear microphonics were recorded in response to Gaussian noise from the round window of Mongolian gerbils. A nonlinear systems identification procedure provided the frequency-domain parameters of a third-order polynomial equation describing cochlear mechano-electric transduction (MET). Exposure to an 8 kHz pure tone at 100 dB SPL for 20 min reduced the magnitude of the linear, quadratic, and cubic terms significantly. Animals exposed to a 1- or 4-kHz pure tone showed changes in the quadratic term. Differentiation of the polynomial equation and algebraic manipulations of the coefficients provided physiologic indices of MET. The sensitivity, saturation voltages, and sound pressures required to saturate MET were altered in animals exposed to an 8-kHz pure tone. Limited changes occurred in animals exposed to a 1- or 4-kHz pure tone.

Animals↗
PubMed1996

Characterizing cochlear mechano-electric transduction using a nonlinear systems identification procedure.

A nonlinear systems identification technique [J. S. Bendat, Nonlinear System Analysis and Identification from Random Data (Wiley, New York, 1990)] provided the frequency-domain parameters of a third-order system polynomial equation describing cochlear mechano-electric transduction (MET) in Mongolian gerbils. The magnitude of the linear system term was the largest followed by the cubic and quadratic terms. The phase of the linear and cubic system terms differed by approximately 180 deg and the phase of the quadratic term lay between. Between-animal and within-animal variability was smallest for the linear and cubic terms, and largest for the quadratic term. Summing linear and nonlinear coherence functions revealed that the third-order system polynomial equation characterized approximately 83% of MET for low frequencies and 92% for high frequencies. Animals exposed to a 4-kHz pure tone at 100 dB SPL for 20 min showed changes in the magnitude and phase of the parameters of the third-order polynomial equation. An increase in linear coherence and a decrease in nonlinear coherence occurred at frequencies centered at the exposure frequency. Below the exposure frequency, linear coherence decreased and nonlinear coherence increased. Summation of the coherence functions showed that the third-order polynomial equation characterized MET better after exposure to the pure tone.

Animals↗
PubMed1995

Functional nuclear epidermal growth factor receptors in human choriocarcinoma JEG-3 cells and normal human placenta.

Immunocytochemistry with a monoclonal antiepidermal growth factor (anti-EGF) receptor antibody directed against the extracellular domain which can inhibit ligand binding to the receptors showed that nuclei of choriocarcinoma JEG-3 cells and normal placental trophoblasts were distinctly immunostained for EGF receptors. This finding led us to investigate the structure and function of nuclear EGF receptors. Western immunoblotting revealed that cell membranes, isolated intact pure nuclei, and nuclear membranes contain a 170-kilodalton EGF receptor protein. Covalent receptor cross-linking demonstrated that the 170-kilodalton receptor protein in nuclei and nuclear membranes can bind [125I]EGF just as in cell membranes, and that this binding is inhibited by excess unlabeled EGF. As in cell membranes, the addition of EGF resulted in an increased receptor autophosphorylation in the nuclei and nuclear membranes. In addition, the activated receptor kinase stimulated, and in some cases inhibited, tyrosine phosphorylation of a number of lower molecular size proteins, especially in nuclei and nuclear membranes. Although the identity of these proteins is not known, none of them could bind [125I]EGF. The addition of EGF to isolated nuclei resulted in a time-dependent specific transcriptional inhibition of hCG/LH receptor gene. In summary, our data demonstrating the presence of functional nuclear EGF receptors are novel, potentially important, and go against the traditional concepts of growth factors action. The nuclear receptors have the capacity to transduce signals from EGF and may mediate intracrine and paracrine actions of EGF in the regulation of trophoblast functions.

Blotting, Western↗
PubMedDate not supplied

Plasma membrane calcium ATPase gene expression in bovine lens epithelium.

Plasma membrane calcium adenosine triphosphatase (Ca(2+)-ATPase) is an energy-dependent protein responsible for transporting cytosolic calcium across the plasma membrane. Multiple plasma membrane Ca(2+)-ATPase isoforms are expressed from four genes (PMCA1-4) and alternative mRNA splicing. We have studied PMCA gene expression in bovine lens epithelium tissues by reverse transcription-polymerase chain reaction, Southern blot, and Northern blot hybridization. All four PMCA genes are expressed in the lens epithelium, the PMCA3 transcript being the most abundant. The transcripts for PMCA1, PMCA2, and PMCA4 exist in decreasing order of abundance. There is no evidence for the expression of any novel PMCA genes in bovine lens epithelium.

Animals↗