Biomedical subjects

B He

Publications and source records attributed to B He.

At least 163 records · Page 9Linked to original sources

PubMed1998

A computer simulation study of cortical imaging from scalp potentials.

In this paper, computer simulation studies were conducted to test the feasibility of imaging brain electrical activity from the scalp electroencephalograms. The inhomogeneous three-concentric-sphere head model was used to represent the head volume conductor. Closed spherical dipole layers, consisting of several thousand uniformly distributed dipoles, were used to reconstruct the cortical potential maps corresponding to neuronal sources located inside the brain. Simulation results indicate that the present procedure can image both cortical and deep sources, and for the cortical sources, a spatial resolution as high as 1.2 cm can be achieved.

Brain↗

PubMed1998

Body surface Laplacian mapping in patients with left or right ventricular bundle branch block.

Body surface Laplacian maps (BSLMs) have been previously reported to provide enhanced capability in localizing and resolving multiple spatially separate myocardial events. However, only a few studies have been reported on the clinical applications of BSLM. To test the clinical utility of BSLMs, BSLMs and body surface potential maps (BSPMs) during ventricular depolarization for complete right or left ventricular bundle branch block (CRBBB or CLBBB) were studied in ten patients in each group. As a control group, ten healthy subjects were also studied using the same procedure. One hundred and twenty-eight electrodes were placed uniformly over the entire chest and back of the subjects. BSLMs were computed from recorded potentials, using a numerical algorithm. The BSLMs showed multiple and more localized positive and negative activities compared with the BSPMs. In healthy subjects, the BSLMs showed multiple areas of positive activity overlying the RV, LV, and the RV outflow, and negative activity corresponding to RV free-wall breakthrough and LV anterolateral breakthrough sites, whereas the BSPMs could not separate RV and LV activities. In the patients with CRBBB, the BSLMs showed more localized areas of activity corresponding to the LV apex breakthrough and LV lateral breakthrough, and separated LV lateral and posterior activation. In the patients with CLBBB, the BSLMs showed multiple RV activation, and propagating activation of LV from lateral to posterior. The BSLMs appear to provide enhanced capability in detecting multiple ventricular electrical events associated with normal and abnormal conduction and a more detailed activation sequence of both ventricles in healthy subjects and in the patients with CRBBB and CLBBB. BSLM may provide an important alternative to other imaging modalities in localizing cardiac electrical activity noninvasively.

Action Potentials↗

PubMed1998

The myelin basic protein gene in multiple sclerosis: identification of discrete alleles of a 1.3 kb tetranucleotide repeat sequence.

Myelin basic protein (MBP) is a potential autoantigen in multiple sclerosis (MS) and its gene therefore is an attractive candidate to confer genetic susceptibility to this disease. Linkage and association with certain alleles of a 1.2 kb tetranucleotide repeat region 5' to the MBP gene with MS have been reported in Finnish patients, and an association has been reported from Denmark. However, these findings have not been confirmed in subsequent analyses in other populations. A limitation of previous studies has been the low resolution of the typing procedure. We have investigated the same polymorphism in thirty-four Swedish nuclear families with 2 or 3 MS patients. and in 149 unrelated Swedish MS patients and 95 healthy controls using a fluorescence-based semi-automated technique which allowed the identification of discrete tetrarepeat numbers. Neither parametric two-point linkage analysis nor a nonparametric affected pedigree members analysis showed any sign of linkage. In addition, the distribution of alleles was similar in patients and controls. We conclude that the MBP gene does not influence susceptibility to MS in Swedish patients.

Alleles↗

PubMed1998

Glycogen synthase kinase 3beta and extracellular signal-regulated kinase inactivate heat shock transcription factor 1 by facilitating the disappearance of transcriptionally active granules after heat shock.

Heat shock transcription factor 1 (HSF-1) activates the transcription of heat shock genes in eukaryotes. Under normal physiological growth conditions, HSF-1 is a monomer. Its transcriptional activity is repressed by constitutive phosphorylation. Upon activation, HSF-1 forms trimers, acquires DNA binding activity, increases transcriptional activity, and appears as punctate granules in the nucleus. In this study, using bromouridine incorporation and confocal laser microscopy, we demonstrated that newly synthesized pre-mRNAs colocalize to the HSF-1 punctate granules after heat shock, suggesting that these granules are sites of transcription. We further present evidence that glycogen synthase kinase 3beta (GSK-3beta) and extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) participate in the down regulation of HSF-1 transcriptional activity. Transient increases in the expression of GSK-3beta facilitate the disappearance of HSF-1 punctate granules and reduce hsp-70 transcription after heat shock. We have also shown that ERK is the priming kinase for GSK-3beta. Taken together, these results indicate that GSK-3beta and ERK MAPK facilitate the inactivation of activated HSF-1 after heat shock by dispersing HSF-1 from the sites of transcription.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1998

Inactivating mutation in the human parathyroid hormone receptor type 1 gene in Blomstrand chondrodysplasia.

A single homozygous nucleotide exchange in exon E3 of the gene encoding the parathyroid hormone receptor type 1 (PTHR1) was identified in an infant with Blomstrand chondrodysplasia born to consanguineous parents. This alteration changes a strictly conserved proline residue at position 132 in the receptor's amino terminal extracellular domain to leucine. COS-1 cells expressing the mutant receptor did not accumulate cyclic adenosine 3',5'-monophosphate in response to PTH or PTH-related peptide (PTHrP) and did not bind the radiolabeled ligand. Expression of the mutant protein on the cell surface of transiently transfected COS-1 cells and in growth plate chondrocytes derived from the affected infant suggests that proline 132 is critical for the receptor's intrinsic binding activity. These findings suggest that the Blomstrand form of human short-limbed dwarfism arises from defective PTHR1 signaling in the developing cartilaginous skeleton.

Amino Acid Sequence↗

PubMed1998

Mutations in the promoter of adenylyl cyclase (AC)-III gene, overexpression of AC-III mRNA, and enhanced cAMP generation in islets from the spontaneously diabetic GK rat model of type 2 diabetes.

Glucose-induced insulin release is decreased in the spontaneously diabetic GK rat, a nonobese rodent model of type 2 diabetes. Forskolin restores the impaired insulin release in both the isolated perfused pancreas and isolated islets from these rats (Abdel-Halim et al., Diabetes 45:934-940, 1996). We demonstrate here that the insulinotropic effect of forskolin in the GK rat is due to increased generation of cAMP and that it is associated with overexpression of adenylyl cyclase (AC)-III mRNA and gene mutations. The AC-III mRNA overexpression was demonstrated by in situ hybridization using oligonucleotide probes binding to different regions of the rat AC-III mRNA. It was associated with the presence of two point mutations identified at positions -28 bp (A --> G) and -358 bp (A --> C) of the promoter region of the AC-III gene and was demonstrable in both GK rat islets and peripheral blood cells. Transfection of COS cells with a luciferase reporter gene system revealed up to 25-fold increased promoter activity of GK AC-III promoter when compared with normal rat promoter (P < 0.0001). In conclusion, forskolin restores the impaired insulin release in islets of the GK rat through enhanced cAMP generation. This is linked to overexpression of AC-III mRNA in GK islets due to two functional point mutations in the promoter region of the AC-III gene.

Adenylyl Cyclases↗

PubMed1998

Longer-term fourth ventricular 5-thioglucose infusion increases body fat in the rat.

5-Thioglucose (5-TG) has been shown to increase food intake after acute administration. To determine the longer-term effects of 5-TG on feeding and body composition, thirty-four female Sprague-Dawley rats were cannulated into the fourth ventricle and infused with artificial CSF and either 0.01 M 5-TG or 0.1 M 5-TG using osmotic pumps. Food intake and body weight were monitored daily. Rats were killed after 14 days of infusion. Carcass and fatpad weights were measured, and body compositions were determined. Food intake was not different during the first week of infusion; however, cumulative food intake was decreased in the 0.1 M 5-TG group during the second week as compared to the CSF control group. Body weight and carcass weight of this group also decreased as compared to the control. The group receiving the higher dose of 5-TG (0.1 M) had increased fatpad weights in all three depots examined (inguinal, retroperitoneal, and perimetrial depot); the group with lower dose of 5-TG infusion (0.01 M) increased the fatpad weights in the retroperitoneal and perimetrial depot, as compared to the CSF group. Data from the body composition analysis were consistent with the results of the fatpad weights. In conclusion, the present study demonstrated that chronic fourth ventricular 5-TG infusion increased body fat without increasing food intake, suggesting that energy expenditure is decreased under this condition. The results of this study indicate that glucose metabolism in the hindbrain is important in the control of energy expenditure, body fat deposition, and thus energy balance regulation.

Adipose Tissue↗

PubMed1998

Antibiotic activities and affinities for bacterial cell wall analogue of N-demethylvancomycin and its derivatives.

N-Demethylvancomycin, which has been clinically used in China, is one member of vancomycin group (glycopeptide) antibiotics. It differs from vancomycin only in that methyl group on the amino group of the N-terminal residue of vancomycin has been replaced by H. By reductive alkylation of N-demethylvancomycin, we synthesized N-alkyl and N,N'-dialkyl N-demethylvancomycins, which closely correlated with vancomycin in structure. The association constants of the complexes of N-demethylvancomycin and its analogues with di-N-Ac-L-Lys-D-Ala-D-Ala and the antibiotic activity against Staphylococcus aureus of the glycopeptides were determined. Results showed that N-demethylvancomycin has higher affinity for bacterial cell wall analogue di-N-Ac-L-Lys-D-Ala-D-Ala and more potent antibiotic activity against Staphylococcus aureus than vancomycin. Both N-alkylation and N,N'-dialkylation of N-demethylvancomycin reduced the affinity and antibiotic activity. The longer the alkyl groups, the less potent antibiotic activities and lower affinities have the glycopeptides. The antibiotic activities against Staphylococcus aureus of N-demethylvancomycin and its analogues roughly parallel their affinities for di-N-Ac-L-Lys-D-Ala-D-Ala.

Alkylation↗

PubMed1998

[Antagonistic action of organic selenium on lead poisoning].

Ninety white rats were treated with liquid lead acetate. When the concentration of lead in urine was more than (0.81 +/- 0.26) mg/L and blood lead was more than (4.8 +/- 0.33) mg/L, the rats were divided into three groups randomly. The oxygenic damage indicators in serum showed SOD activity decreased and MDA content increased. In one group of lead rats fed with an organic selenium compound (code FCQY) the SOD activities were high and the lipid peroxidation was inhibited compared with controls without selenium supplementation. The lead contents of bone, kidney and liver were measured. The results suggested that the organic selenium compound could interfere with the absorption and accumulation of lead.

Animals↗

PubMed1998

The effect of dimethyl sulfoxide on activation of the major immediate early promoter of human cytomegalovirus.

OBJECTIVE: To evaluate the effect of dimethyl sulfoxide (DMSO) on the major immediate early promoter of human cytomegalovirus. METHODS: THP-1 cells were transfected with plasmids pCAT760, pIE1-163, pIE1-183, pIE1-193 and pIE1-213, respectively, and exposed to dimethyl sulfoxide in the presence or absence of lipopolysaccharide. The extracts of these cells were performed by chloramphenicol acetyl transferase assay. The nuclear extracts of THP-1 cells treated with dimethyl sulfoxide in the presence or absence of lipopolysaccharide were prepared for the DNA binding reaction by electrophoretic mobility shift assay. RESULTS: Dimethyl sulfoxide increases the expression of the cytomegalovirus major immediate early promoter, and also upregulated expression of the minimal major immediate early promoter containing triplicates of either the 18 base pair or 19 base pair sequences. Furthermore, gel mobility shift assays showed that dimethyl sulfoxide enhances Nuclear Factor kappa B and CyclicAMP response element binding protein to bind to the 18 base pair and 19 base pair repeats. CONCLUSIONS: One mechanism whereby DMSO enhances human cytomegalovirus replication is through upregulating the major immediate early promoter. This effect on human cytomegalovirus gene expression is, in part, related to enhanced Nuclear Factor kappa B and CyclicAMP response element binding protein activity.

Cyclic AMP Response Element-Binding Protein↗

PubMed1998

[Expression of surfactant protein SP-A, SP-B, and SP-C mRNA in lungs of rats with bleomycin-induced pulmonary fibrosis].

OBJECTIVE: The expressions of surfactant protein (SP)SP-A, SP-B, and SP-CmRNA in lungs of rats with bleomycin-induced pulmonary fibrosis were studied. METHOD: A single dose of bleomycin(BLM) was intratracheal injected to induce pulmonary fibrosis of rats. Animals were killed at day 3, 7, 14 and 28 after BLM administration. The total RNA was extracted from the lung tissue. The expressions of SPsmRNA were analyzed with Northern blot. RESULT: The number of alveolar type II epithelial cells increased in BLM-administered rats. The expressions of SP-A, SP-B and SP-CmRNA decreased at day 3 after BLM administration and decreased maximally at day 7, and then began to increase at day 14 and significantly increased at day 28, though they were still below the control levels. CONCLUSION: The results show that the changes of expressions of SP-A, SP-B and SP-CmRNA occur during the development of bleomycin-induced pulmonary fibrosis in rats and they may play a role in the pathogenesis of lung fibrosis.

Animals↗

PubMed1998

[Expressions of TNF alpha, PDGF in alveolar type II epithelial cells of rats with bleomycin-induced pulmonary fibrosis].

OBJECTIVE: The expressions of TNF alpha and PDGF in alveolar type II epithelial cells of rats with bleomycin(BLM)-induced pulmonary fibrosis were studied. METHOD: A single intratracheal injection of BLM was administrated to induce pulmonary fibrosis of rats. Animals were killed at day 3,7,14 and 28 after BLM-administration. The immunohistochemical methods were used to analyze the expressions of TNF alpha and PDGF proteins in alveolar epithelium of rats. The total RNA was extracted from the alveolar type II epithelial cells of rats and the expressions of TNF alpha and PDGF mRNA were analyzed with Northern blot. RESULT: TNF alpha and PDGF were expressed in the alveolar type II epithelial cells of BLM-administrated rats. The expression of TNF alpha elevated in median and late-stage of the process and reached the peak at day 28. While the expression of PDGF elevated in early-stage and reached the peak at day 7. By contrast, TNF alpha and PDGF weren't expressed in the alveolar type II epithelial cells of normal controls. CONCLUSION: The results show that the alveolar type II epithelial cell from rats with pulmonary fibrosis overexpresses TNF alpha and PDGF and they may play roles in the pathogenesis of lung fibrosis.

Animals↗

PubMed1998

[Severity of obstructive sleep apnea syndrome relates to sleep architecture changes].

OBJECTIVE: To explore how obstructive sleep apnea syndrome (OSAS) affects sleep architecture and if OSAS severity and treatment relate to it. METHOD: A computer-assistant diagnostic system was used for polysomnography(PSG) recording. Respiratory events were scored automatically and corrected manually. Sleep was scored manually according to the standard set by Rechtschaffen. 31 controls and 147 OSAS patients(RDI > or = 5) were defined by PSG. 11 OSAS patients(RDI = 62.5 +/- 20.8) accepted nCPAP therapy. PSG were recorded both before and during nCPAP treatment. RESULT: (1) Compared with controls, OSAS group had increased sleep shift number (120 +/- 71 vs 92 +/- 60, P = 0.0106); (2) The number of slow wave sleep(SWS) (5 +/- 9 vs 8 +/- 8, P = 0.0035) and the ratio of total SWS time over total sleep time(TST) (5% +/- 8% vs 8% +/- 9%, P = 0.0062), were decreased and the rate of SWS deprivation(48% vs 26%, P < 0.05) were increased greatly in OSAS patients; (3) REM were less affected by OSAS than SWS because the ratio of its total time over TST, its onset number and deprivation rate had no significant difference between the two groups; (4) OSAS group had increased number of WASO (wake after sleep onset) (27 +/- 28 vs 19 +/- 18, P = 0.017) but the ratio of total WASO time over total sleep period had no significant difference between the two groups; (5) The ratio of total RWS(rapid wave sleep) time over TST (94 +/- 10 in OSAS group vs 91 +/- 12, P = 0.0136) and total RWS number(88 +/- 54 in OSAS group vs 65 +/- 45, P = 0.0075) were increased in OSAS group; (6) The above parameters were obviously disturbed in OSAS patients with RDI > or = 25 but had almost no change in patients with RDI < 25 compared with controls. (7) nCPAP could improve the above parameters but only number of WASO(no therapy: 34 +/- 20 vs therapy: 23 +/- 22, P = 0.011), shift number (no therapy: 151 +/- 62 vs therapy: 97 +/- 50, P = 0.019) and the ratio of total RWS time over TST (no therapy: 115 +/- 58 vs therapy: 69 +/- 34, P = 0.025) had statistical significance. CONCLUSION: OSAS severity relates to sleep architecture changes. Those had RDI < 25 had no change compared with control group. Sleep architecture changes could be improved by effective nCPAP therapy.

Adult↗

PubMed1998

[Sequencing of a beta-amylase gene from Bacillus firmus].

The gene encoding a beta-amylase from Bacillus firmus 725 was sequenced. The sequenced DNA of 2012 bp contains one open reading frame of 1406 nucleotides without a translation stop codon. The deduced amino acid sequence homology with those known bacterial and some plant beta-amylase was 98% for Bacillus polymyxa 72, 98% for Bacillus polymyxa ATCC8523, 82% for Bacillus circulans, 54% for Clostridium thermosulfurogenes, 49% for Bacillus cereus BQ10-S1, 50% for Bacillus cereus var. mycoides, 36% for barley, and 36% for soybean Eleven well-conserved regions were found among the amino acid sequences of the nine beta-amylases.

Amino Acid Sequence↗

PubMed1998

[Oxygen free radical scavening activity and anti-lipid peroxidation of tea polyphenol].

The oxygen free radical scavenging activity and anti-lipid peroxidation of tea polyshenol were studied in vitro. Tea polyphenol possessed significantly scavening effect on hydorxyl radical produced by Fenton recation and superoxide anion produced by xanthine-xanthine oxidase system (IC50 were 919.6 mg/L and 836 mg/L espectively). Tea polyphenol could significantly inhibit the lipid peroxidation of brain omogenate and cerbral mitochondrial membrane induced by hyderxyl radical. The results suggest that the anti-lipid peroxidation of tea polyphenol may be related to its scavenging effects on oxygen free radicals.

Animals↗

PubMed1998

[Identification of crude drugs from genus Leonurus].

The structure in cross section of stem and lamina of 9 species and 1 variety from genus Leonurus, whose herb used as Yimu Cao, were reported. Diagnostic characteristics were listed out in a key for identification.

Drugs, Chinese Herbal↗

PubMed1998

[Effects of herba Pogostemonis on gastrointestinal tract].

The effects of the three extracts (Decoction, oil-free decoction and volatile oil) of Herba Pogostemonis on gastrointestinal tract were studied. The results showed that all the three extracts inhibited the automatic contraction and Ach, BaCl2-induced spasmodic contraction of isolated rabbit intestine, among the three extracts the volatile oil was the most potent. In vivo the decoction and the oil-free decoction could depress gastric evacuation and inhibit the normal and neostigmine-induced intestinal propellent movement in mice, but the volatile oil could not. The decoction and the oil-free decoction also increased gastric secretion of acid and activity of pepsin and amylase. Furthermore, the decoction and the oil-free decoction reduced the incidence of diarrhea induced by senna but volatile oil enhanced cooperatively. All the three extracts relieved the gripping pain induced by abdominal administration of acetic acid, and the effect of decoction was more potent that the others. The above results revealed that the effective components of Herba Pogostemonis may be mainly water-solube.

Animals↗

PubMed1998

[Direct determination of trace elements in tungsten products with ICP-AES].

A direct determination of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti and V in tungsten products with ICP-AES is presented. The influence of tungsten matrix is studied. Based on the selected optimum operating parameters, the feasibility of the proposed method is evaluated by analyzing three WO3 National References. The results are satisfactory.

English Abstract↗