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Biomedical subjects

H Xu

Publications and source records attributed to H Xu.

At least 199 records · Page 11Linked to original sources
PubMed2001

[Ultrasonic multiple measurement estimation of fetal weight in parturient].

OBJECTIVE: To evaluate the ultrasonic measurements of parturient fetal cerebellar diameter (CD), liver length(LL), kidney length (KL) and femur thigh soft tissue thickness(FSTT) for the estimation of fetal weight. METHODS: Ultrasonic measurements of the parturient fetal cerebellar diameter, liver length, kidney length and femur thigh soft tissue thickness were made in 115 cases. The data on these parameters were analyzed with statistical methods, and a multiple linear regressional equation for predicting the fetal body weight was derived. The calculated value of fetal body weight and the estimated parameters of the fetal body were compared with the actually measured values immediately after birth. The error of estimation was analyzed. RESULTS: CD, LL, KL and FSTT were significantly correlated with neonatal birth weight, the coefficient of multiple correlation R = 0.9425 (P < 0.001); among the 115 cases, 101 had absolute error less than +/- 200 g, with an agreement rate of 88%. The sensitivity and accuracy for detection of normal fetus were 98.13% and 94.78% respectively. The multiple linear regression equation derived was BW = -1009.914 + 356.1303FSTT + 354.0682KL + 236.8484 LL + 179.7384 CD. CONCLUSION: The equation is a simple, accurate and valuable equation for the estimation of fetal weight and can be used in clinical practice.

Birth Weight↗
PubMed2001

[Preliminary study of closing cleft of soft palate at an early age for complete cleft palate].

OBJECTIVE: The aim is to introduce the method closing the soft palate at an early age in order to produce better speech and lessen interruption to the development of maxilla. METHODS: Clinical data of 37 cases with treated cleft were preliminarily analyzed. Some dental casts were measured. RESULTS: 1. No complications of anaesthesia and surgery. Except 2 cases whose soft palates were split after surgery were observed as they were coughing. 2. A reduction in the width of the hard palate cleft was noticed. CONCLUSION: Closing the soft palate at an early age is possible and safe. It shows that the Langebeck method could be used to close the hard palate of patients at an early age.

Child, Preschool↗
PubMed2001

[The influence of palatoplasty and tympanotomy on middle ear function in cleft palate patients].

OBJECTIVE: The aim of this study is to explore the influence of palatoplasty and tympanotomy on middle ear function or hearing condition in cleft palate patients. METHODS: A total of 22 ears with otitis media with effusion in cleft palate patients were inserted with PE tubes, and Pre- and post-operative hearing level and middle ear function in these patients were tested and compared respectively, in order to demonstrate the action of tympanotomy and PE insertion on hearing and middle ear function. Another 38 patients with cleft palate were operated in their early age with the proper operation method, and pre- and post-operative middle ear function were examined and compared to show the influence of the operation on the middle ear function. RESULTS: PE Tube insertion and tympanotomy changed the pressure condition of middle ear cavity and raised the hearing level about 17 dB in the middle-ear-diseased cleft palate patients, and patients with palatoplasty did not show obvious changes in middle ear function in the short-term trail. CONCLUSION: Early and active tympanotomy do help in improving the function of the middle ear, and it is suggested to improve patients' hearing and middle ear function as early as possible. Palatoplasty did not affect the function of middle ear.

Cleft Palate↗
PubMed2001

[The influence of the hamulotome and interplatal incision on the middle ear function].

OBJECTIVE: The aim of this study is to explore the effect of hamulotome on the eustachian tube function and verify the function of the tensor veli palatili muscle on eustachian tube. METHODS: Single-sided hamulotome were carried out in the rabbits under the direct visual. And the middle ear cavity mucosa of the rabbits was collected at different intervals and dyed with PAS and PH to observe the middle ear changes under microscope. RESULTS: Middle ear function changed obviously after the hamulotome, with increase in globular cells, submucosal edema and inflammatory cells. And mucin was not found in several cavities. CONCLUSION: Hamulotome do affect on the middle ear function and should not be damaged in order to protect the middle ear function in some patients.

Animals↗
PubMed2001

[Sympathetic-sensory coupling in neuropathic pains].

Peripheral tissue and nerve injury lead to chronic pain symptoms, including spontaneous pain, allodynia and hyperalgesia. Sympathetic nervous system involves in pathological changes above, either through development of abnormal sympathetic function or through its effects on abnormally functioning afferent nerves, thereby to cause many neuropathic pains. This review focuses on the progress at present of sympathetic-sensory coupling and its receptors, intracellular and neural mechanisms.

Animals↗
PubMed2001

[Effect of folic acid and supplemented with vitamin A and vitamin E on depressing teratogenesis induced by cyclophosphamide].

The effect of folic acid and the combined effect of folic acid(FA) + vitamin A + vitamin E on the prevention of teratogenesis induced by cyclophosphamide during pregnancy were observed. The results showed that cyclophosphamide resulted a decreased weight and length of the fetuses, an increased rate of neural tube defects and a retardation of ossification centers. The neural tube defects rates in the groups with no any supplementation, supplemented with folic acid alone and supplemented with FA + vitamin A + vitamin E were 87.27%, 42.93% and 30.08% respectively(P < 0.01). The supplementation of FA or the combined supplementation resulted also in greater fetal weight and length, increased ossification of supraoccipital bone (P < 0.01). The study suggested that the combined effect of FA, vitamin A and vitamin E was superior to FA alone.

Animals↗
PubMed2001

[Experimental study on effect of congsheng capsule on expression of brain derived neurotrophic factor and tyrosinkinase mRNA in forebrain of rats after cortical devascularization].

OBJECTIVE: To study the effect and mechanism of Congsheng Capsule (CSC) on brain derived neurotrophic factor (BDNF) and tyrosinkinase (trkB) mRNA in forebrain of rats after cortical devascularization. METHODS: The rat devascularization model was established, and expression of BDNF mRNA and trkB mRNA were determined by hybridization in situ method. RESULTS: Expression of BDNF mRNA and trkB mRNA reduced obviously in the cerebral cortex and hippocampus of devascularization model, especially in hippocampal CA1 subregion. There was trkB mRNA but no BDNF mRNA expression in the macrocyte basal nuclei (MBN). CSC significantly increased the decreased BDNF and trkB mRNA in cortex, hippocampus and MBN compared with placebo group. CONCLUSION: CSC could salvage the degenerating neurons and maintain their survival after cortical devascularization by increasing the expression of BDNF and trkB mRNA and improving the synthesis of BDNF mRNA and trkB protein.

Animals↗
PubMed2001

[Effect of xiongshao capsule on vascular remodeling in porcine coronary balloon injury model].

OBJECTIVE: To study the effect of Xiongshao Capsule (XS) on vascular remodeling in porcine coronary balloon injury model. METHODS: Restenosis model was established by oversized balloon injury at mid-region of the left anterior descending coronary artery. The effect of drugs on late lumen loss and vascular remodeling was evaluated with quantitative histological method by combining results from histopathological analysis and coronary arteriography. RESULTS: Vascular remodeling explained (59 +/- 20)% of late lumen loss. All drugs significantly reduced late lumen loss 4 weeks after balloon injury (P < 0.05 or 0.01). Both low-dose and high-dose XS markedly reduced late lumen loss resulting from vascular remodeling, as compared with the control group (P < 0.05 and P < 0.01 respectively). CONCLUSION: Vascular remodeling played an important role in late lumen stenosis after balloon injury of coronary artery. XS could significantly inhibit pathological vascular remodeling after balloon injury, thus reduce late lumen loss and prevent restenosis.

Angioplasty, Balloon, Coronary↗
PubMed2001

[rDNA its sequencing of Herba Dendrobii (Huangcao)].

AIM: To study the genetic diversity of ITS sequences of Herba Dendrobii (Huangcao) and analyze the utility of ITS sequences in molecular authentication of Herba Dendrobii (Huangcao) and phylogenetic of Dendrobium. METHODS: The ITS gene fragment was amplified using a pair of primers. The PCR products were purified and sequenced by the methods of Sanger Dideoxy. RESULTS: The DNA sequence of 228-233 bp ITS 1, 242-247 bp ITS 2 gene fragments and 5.8S rDNA were obtained from 14 samples of Dendrobium. The interspecific substitution varies from 11.79% to 31.58% at ITS 1 and 10.29% to 25.30% at ITS 2. The intraspecific substitution of D. nobile is 0.87% at ITS 1 and without difference at ITS 2. The substitution between Dendrobium and outgroup varies from 23.56% to 36.89% at ITS 1 and 26.52% to 33.31% at ITS 2. The phylogenetic tree based on ITS 1 and ITS 2 data was set up. CONCLUSION: The ITS 1 and ITS 2 gene fragments were highly conservative at intraspecific level in Dendrebium, while they were less conservative at interspecific level in D. nobile. They were least conservative between Dendrobium and outgroup. Hence, the sequence of this fragment is a good molecular marker for authentication of the Huangcao. But, further study is necessary for the phylogenetic of Dendrobium.

Base Sequence↗
PubMed2001

[Effect of pH on the permeability of timolol maleate across isolated rabbit cornea].

AIM: To study the effect of pH on the transcorneal permeability of timolol maleate (TM). METHODS: The apparent distribution coefficients of TM were determined. The permeability of TM across isolated rabbit cornea was measured using in vitro method at various pH. RESULTS: The partition coefficient and pKa of TM were 63.63 and 9.17 respectively. At neutral pH, the apparent permeation coefficient of TM was 1.43 x 10(-5) cm.s-1. When the pH varied from 6.65 to 9.20, the cumulative amount for timolol transcorneal penetration increased 1.3 times and the lag time decreased more than 19-folds. The calculated permeability coefficients of ionized and un-ionized timolol were 1.29 x 10(-5) cm.s-1 and 4.22 x 10(-5) cm.s-1, respectively. CONCLUSION: Timolol penetrated corneal membrane mainly as free base by intracellular pathway, and corneal epithelium was the rate-limiting barrier.

Animals↗
PubMed2001

[The late achievements of volume CT].

This paper mainly introduces the late achievements of theories and methods for this technology. And we look into the future of them at the end of this paper. The main contents include direct volume CT and its fast algorithms, volume imaging for non-complete data, direct volume CT based on digital radiography and reverse geometry X-ray.

Algorithms↗
PubMed2000

Negative regulation of CD8+ T cell function by the IFN-induced and double-stranded RNA-activated kinase PKR.

The IFN-induced and dsRNA-activated kinase (PKR) mediates the antiviral and antiproliferative effects of IFN-alpha and IFN-gamma. Despite these findings, PKR:(-/-) mice have no overt immunological phenotype. Here we tested the role of PKR in cellular immunity by determining the induction and elicitation of contact hypersensitivity in PKR:(-/-) mice, a model of T cell-mediated immunity. When compared with wild type, the magnitude of contact hypersensitivity responses in PKR:(-/-) mice were 2-fold higher and of extended duration. This was also observed when naive recipients of immune CD8(+) T cells from sensitized PKR:(-/-) and CD4(+) T cells from sensitized wild-type PKR:(+/+) or PKR:(-/-) mice were challenged with hapten, indicating a regulatory defect intrinsic to the CD8(+) T cell population. Isolated lymph node T cells from PKR:(-/-) mice were hyperproliferative during Con A-mediated stimulation. These results implicate PKR for the first time in the growth control of mature T lymphocytes and give insight into the negative regulation of CD8(+) T cell-mediated immune responses.

Adoptive Transfer↗
PubMed2000

Human RNase III is a 160-kDa protein involved in preribosomal RNA processing.

A human RNase III gene encodes a protein of 160 kDa with multiple domains, a proline-rich, a serine- and arginine-rich, and an RNase III domain. The expressed purified RNase III domain cleaves double-strand RNA and does not cleave single-strand RNA. The gene is ubiquitously expressed in human tissues and cell lines, and the protein is localized in the nucleus of the cell. The levels of transcription and translation of the protein do not change during different phases of the cell cycle. However, a significant fraction of the protein in the nucleus is translocated to the nucleolus during the S phase of the cell cycle. That this human RNase III is involved in processing of pre-rRNA, but might cleave at sites different from those described for yeast RNase III, is shown by antisense inhibition of RNase III expression. Inhibition of human RNase III expression causes cell death, suggesting an essential role for human RNase III in the cell. The antisense inhibition technique used in this study provides an effective method for functional analysis of newly identified human genes.

Amino Acid Sequence↗
PubMed2000

Rab6c, a new member of the rab gene family, is involved in drug resistance in MCF7/AdrR cells.

A new Rab6 homolog cDNA, Rab6c, was discovered by a hypermethylated DNA fragment probe that was isolated from a human multidrug resistant (MDR) breast cancer cell line, MCF7/AdrR, by the methylation sensitive-representational difference analysis (MS-RDA) technique. Rab6c was found to be under-expressed in MCF7/AdrR and MES-SA/Dx5 (a human MDR uterine sarcoma cell line) compared with their non-MDR parental cell lines. MCF7/AdrR cells expressing the exogenous Rab6c exhibited less resistance to several anti-cancer drugs, such as doxorubicin (DOX), taxol, vinblastine, and vincristine, than the control cells containing the empty vector. Flow cytometry experiments confirmed that the transfectants' diminished resistance to DOX was caused by increased drug accumulation induced by the exogenous Rab6c. These results indicate that Rab6c is involved in drug resistance in MCF7/AdrR cells.

Amino Acid Sequence↗
PubMed2000

A single residue contributes to the difference between Kir4.1 and Kir1.1 channels in pH sensitivity, rectification and single channel conductance.

Kir1.1 and Kir4.1 channels may be involved in the maintenance of pH and K+ homeostasis in renal epithelial cells and CO2 chemoreception in brainstem neurons. To understand the molecular determinants for their characteristic differences, the structure-function relationship was studied using site-directed mutagenesis. According to previous studies, Glu158 in Kir4.1 is likely to be the major rectification controller. This was confirmed in both Kir1.1 and Kir4.1. Mutation of Gly210, the second potential rectification controller, to glutamate did not show any additional effect on the inward rectification. More interestingly, we found that Glu158 in Kir4.1 was also an important residue contributing to single channel conductance and pH sensitivity. The E158N Kir4.1 mutant had a unitary conductance of 35 pS and a midpoint pH for channel inhibition (pKa) value of 6.72, both of which were almost identical to those of the wild-type (WT) Kir1.1. Flickering channel activity was clearly seen in the E158N mutant at positive membrane potentials, which is typical in the WT Kir1.1 but absent in the WT Kir4.1. Reverse mutation in Kir1.1 (N171E) reduced the unitary conductance to 27 pS (23 pS in WT Kir4.1). However, the pH sensitivity of this mutant did not show a marked difference from the WT Kir1.1. Therefore, it is possible that a residue(s) in addition to Asn171 is also involved. Thus we studied several other residues in both M2 and H5 regions. We found that joint mutations of Val140 and Asn171 to residues seen in Kir4.1 greatly reduced the pH sensitivity (pKa 6. 08). The V140T mutation in Kir1.1 led to a unitary conductance of approximately 70 pS, and the G210E mutation in Kir4.1 caused a decrease in pH sensitivity of 0.4 pH units. These results indicate that the pore-forming sequences are targets for modulations of multiple channel-biophysical properties and demonstrate a site contributing to rectification, unitary conductance and proton sensitivity in these Kir channels.

Amino Acid Sequence↗