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Biomedical subjects

X Bao

Publications and source records attributed to X Bao.

At least 55 records · Page 3Linked to original sources
PubMed1999

Early intervention promotes intellectual development of premature infants: a preliminary report. Early Intervention of Premature Infants Cooperative Research Group.

OBJECTIVE: To evaluate the effect of early intervention on the intellectual development of the premature infants. METHODS: Premature infants at gestational age of 28-36.9 weeks were randomly divided into two groups: intervention and conventional care groups. Normal newborn infants during the same period were included in the control group (routine care). Up to March 1996, 156 cases were over the age 1.5-2 years (corrected age), 52 in the intervention group, 51 in the conventional care group and 53 in the normal control group. Parents were taught to carry out the 0-2 year intervention program, which included motor, cognitive, speech development and social behavior. Every three months, height, weight and head circumference were measured. At the age of one and a half and two years, all infants in the three groups received infant development tests of Child Development Center of China (CDCC) scale. The examiner did not know which infant had received intervention. RESULTS: There was no significant difference in biological factors among the two premature groups and in cultural and social factors among the three groups. Intelligence tests at the age of one and a half and two years showed that the average mental development index (MDI) in the intervention group was 13.8 and 14.6 higher than those in the conventional care group and the differences were significant. The psychomotor development index (PDI) was 5.2 and 4.7 higher but the differences were not significant. The MDI and PDI in the intervention group and normal control were quite close, but at two years, the MDI and PDI in the intervention group were 5.7 and 7.3 higher than those in the normal control and the differences were significant (P < 0.05). Compared with the normal control, the MDI in conventional care group at one and a half and two years of age were 11.5 and 8.9 lower. The difference was very significant. There were four cases of mental retardation, whose mental development index (MDI) was less then 70 in the conventional care group, but none in the intervention group. CONCLUSIONS: Early intervention can promote intellectual development of the premature infants and may be beneficial to the prevention of mental retardation. Early and intensive intervention can produce better results. Bringing parent's initiative into full play through deepening their understanding of the importance of early intervention is the key to success.

Child Development↗
PubMed1999

[Expression of xylose isomerase gene(xylA) in Saccharomyces cerevisiae from Clostridium thermohydrosulfuricum].

The Clostridium thermohydrosulfuricum xylA gene encoding xylose(glucose) isomerase was cloned in the yeast expression vector pMA91 under the control of the PGK promoter, resulting in pBX-1, and transformed into Saccharomyces cerevisiae. Production of recombinant xylose isomerase was seen in the a Coomassie stained SDS-PAGE gel and the molecular mass was estimated to be 43 kD. The recombinant xylose isomerase showed the highest activity at 85 degrees C and pH7. The specific activity under these condition was 1.0 U/mg protein. At 30 degrees C and 40 degrees C, the relative activity was reduced to 3.7% and 11%, respectively, of the maximum.

Aldose-Ketose Isomerases↗
PubMed1999

[The origin of Chinese animal drug "hu-di-long" (Shanghai pheretima)].

Results of identification showed that the origin of the Chinese animal drug "Hu-Di-Long" is the dried body of Pheretima vulgaris Chen, P. guillelmi (Michaelsen) or P. pectinifera Michaelsen. The results have been specified in the Pharmacopoeia of the People's Republic of China (1995).

Animals↗
PubMed1999

[The development of a two-channel impedance pneumography].

To obtain respiratory signals with impedance method at two measuring frequencies, a high-performance two-channel impedance pneumography was implemented and the software including acquisiting data, showing waves, storing datas were developed. Human experiment was done and the results were also presented.

Breath Tests↗
PubMed1998

Antisense fosB RNA inhibits thrombin-induced hypertrophy in cultured pulmonary arterial smooth muscle cells.

BACKGROUND: We have previously reported that fosB mRNA is induced by hypertrophic stimuli (thrombin, angiotensin II) but not proliferative stimuli (platelet-derived growth factor, basic fibroblast growth factor) in pulmonary arterial smooth muscle cells (PASMCs) (J Biol Chem. 1994;9:6399-6404). Our aim in the present study was to investigate the potential role of FosB in PASMC hypertrophy. METHODS AND RESULTS: Adenoviruses carrying sense or antisense fosB RNA expression cassettes were used to infect cultured PASMCs with the aim of increasing or inhibiting fosB expression, respectively. We examined whether fosB expression modification affected the growth of quiescent PASMCs, thrombin-induced hypertrophy, or platelet-derived growth factor-induced proliferation. PASMC growth was assessed by daily cell number count, determination of [3H]leucine incorporation, and quantification of total cellular protein. Neither an increase nor a decrease in FosB protein expression caused a significant change in the growth of quiescent PASMCs over a period of 96 hours, indicating that FosB alone is not sufficient to induce hypertrophy. Modification of FosB levels did not affect platelet-derived growth factor-induced PASMC proliferation. An increase in FosB expression did not augment thrombin-induced hypertrophy; however, inhibition of FosB expression resulted in a diminution of thrombin-induced hypertrophy by 58+/-6% (P<0.005). CONCLUSIONS: These results suggest that FosB is necessary but not sufficient for thrombin-induced hypertrophy in cultured PASMCs.

Antisense Elements (Genetics)↗
PubMed1998

Somatostatin immunoreactivity in esophageal premotor neurons of the rat.

Esophageal peristalsis is coordinated by premotor neurons localized to the central subnucleus of the nucleus of the solitary tract (NTScen). These premotor neurons project directly to motoneurons within the compact formation of the nucleus ambiguus (NAc). Somatostatin immunoreactive terminals have been previously demonstrated encircling motoneurons in the (NAc) (Cunningham, E.T., Jr. and Sawchenko, P.E., J. Neurosci., 9 (1989) 1668-1682). We combined transsynaptic tracing with pseudorabies virus and immunohistochemistry to localize somatostatin to premotor neurons within the NTScen.

Animals↗
PubMed1998

Brainstem auditory-evoked potential evaluation in children with meningitis.

Brainstem auditory-evoked potential (BAEP) was performed on 101 children with meningitis to assess the incidence of hearing impairment. Fifty-two (51.5%) children had bacterial meningitis, six (5.9%) had viral meningitis, and 43 (42.6%) had aseptic meningitis. Fifty-one (50.5%) patients were assessed before discharge and 50 (49.5%) 9 days to 17 months later (mean = 4 months). BAEP impairment was found in 28 (27.7%) of 101 patients; 24 had sensorineural and four had conductive type of hearing loss, and 17 (60.7%) had unilateral and 11 (39.3%) had bilateral impairment. Hearing threshold was elevated in 22 (21.8%) patients, and the other six had increased latency and interpeak latencies with normal threshold. Frequency of BAEP impairment or hearing loss associated with bacterial meningitis was 34.6% and 30.8%, respectively; frequency associated with aseptic meningitis was 20.9% and 13.9%, respectively. One child with viral meningitis (coxsackie virus) had mild BAEP impairment. Most of the BAEP impairment in the bacterial meningitis group was associated with H. influenzae. Prospective BAEP study was performed in 20 patients randomly at 0.3 to 18 months to assess hearing status after antibiotic treatment, 10 with normal and 10 with abnormal BAEP. All the initially normal BAEP patients remained normal. Of the 10 patients with abnormal BAEP results initially, four returned to normal, two improved, three remained unchanged, and one deteriorated. The incidence of hearing loss after bacterial and aseptic meningitis is high. BAEP is useful to screen for possible hearing loss in children with meningitis, and follow-up BAEP is necessary for those patients with initially abnormal BAEP.

Child↗
PubMed1998

The biosynthesis of erucic acid in developing embryos of brassica rapa

The prevailing hypothesis on the biosynthesis of erucic acid in developing seeds is that oleic acid, produced in the plastid, is activated to oleoyl-coenzyme A (CoA) for malonyl-CoA-dependent elongation to erucic acid in the cytosol. Several in vivo-labeling experiments designed to probe and extend this hypothesis are reported here. To examine whether newly synthesized oleic acid is directly elongated to erucic acid in developing seeds of Brassica rapa L., embryos were labeled with [14C]acetate, and the ratio of radioactivity of carbon atoms C-5 to C-22 (de novo fatty acid synthesis portion) to carbon atoms C-1 to C-4 (elongated portion) of erucic acid was monitored with time. If newly synthesized 18:1 (oleate) immediately becomes a substrate for elongation to erucic acid, this ratio would be expected to remain constant with incubation time. However, if erucic acid is produced from a pool of preexisting oleic acid, the ratio of 14C in the 4 elongation carbons to 14C in the methyl-terminal 18 carbons would be expected to decrease with time. This labeling ratio decreased with time and, therefore, suggests the existence of an intermediate pool of 18:1, which contributes at least part of the oleoyl precursor for the production of erucic acid. The addition of 2-[3-chloro-5-(trifluromethyl)-2-pyridinyloxyphenoxy] propanoic acid, which inhibits the homodimeric acetyl-CoA carboxylase, severely inhibited the synthesis of [14C]erucic acid, indicating that essentially all malonyl-CoA for elongation of 18:1 to erucate was produced by homodimeric acetyl-CoA carboxylase. Both light and 2-[3-chloro-5-(trifluromethyl)-2-pyridinyloxyphenoxy]-propanoic acid increased the accumulation of [14C]18:1 and the parallel accumulation of [14C]phosphatidylcholine. Taken together, these results show an additional level of complexity in the biosynthesis of erucic acid.

Journal Article↗
PubMed1998

Three-dimensional optimization of treatment planning for gamma unit treatment system.

During a treatment using the Leksell gamma unit, the physician and physicist need to determine a treatment plan by changing the parameters such as collimator sizes, the position of isocenters and isocenters' weights. This is a complex problem because the set of parameters is large, especially when targets are geometrically close to a critical structure. For this reason, we present here an optimization algorithm, namely the multiplier penalty method, to mathematically determine those parameters. Two cases are presented in this article: the first one is really planned by a physicist in a clinical treatment, and is redone in our optimization algorithm to show the effectiveness of this method; the second one is theoretical where a critical structure is placed close to the target volume. The results show that this method achieves an excellent conformation to the specified isodose curve with the contour of the target volume, allowing minimal damage to surrounding healthy tissue.

Algorithms↗
PubMed1998

[Detection of Mycobacterium tuberculosis DNA in peripheral blood mononuclear cells from patients with pulmonary tuberculosis by polymerase chain reaction technique].

OBJECTIVE: To evaluate the clinical value of detection of Mycobacterium tuberculosis DNA (MTB-DNA) in peripheral blood mononuclear cells (PBMC) for diagnosis of pulmonary tuberculosis. METHOD: Polymerase chain reaction (PCR) technique was used to amplify gene of 240 bp DNA fragment prepared by Triton X-100 method, and some factors affecting PCR result were also analysed. RESULT: In blood samples of 89 patients with pulmonary tuberculosis and in sputum samples of 84 patients with pulmonary tuberculosis, the positive rates of PCR were 73% and 57% respectively, and the total positive rate of combinative detection of blood and sputum samples was 87% in 84 pulmonary tuberculosis patients. In 30 non-tuberculosis patients, 3 showed MTB-DNA positive. CONCLUSION: PCR technique prepared by Triton X-100 method is rapid, simple, specific, and sensitive for detection of MTB-DNA in PBMC, and its sensitivity and accuracy could be increased in combination with sputum MTB examination. Detection of MTB-DNA in PMBC is of value in diagnosis of pulmonary tuberculosis.

DNA, Bacterial↗
PubMed1998

[Diagnosis and surgical treatment of intramedullary epidermoid cyst of the spinal cord].

OBJECTIVE: To discuss clinical diagnosis and surgical treatment of intra-medullary epidermoid cyst. METHODS: Ten intramedullary epidermoid cysts were confirmed by operatively and pathologically from 1978 to 1995. RESULTS: The tumors were located in the spinal cord. Clinical presentation of this tumor was not specific. On CT scans, eight tumors were characterized by a homogenous low-density lesion and well-defined limits. They usually did not enhance with contrast medium. On MR imaging, four tumors were characterized by an important variability of signal intensity, well-defined limits. All patients underwent resections of epidermoid cyst, 1 total resection, and 9 subtotal resections. Eight cases were followed up from half a year to seven years. No case recurred. CONCLUSION: Total resection of epidermoid cyst is the best choice.

Adolescent↗
PubMed1998

Effects of benazepril on insulin resistance and glucose tolerance in uremia.

This study tested whether the angiotensin-converting enzyme inhibitor (ACEI) benazepril can improve the insulin resistance and glucose tolerance in uremia. Fifteen uremic hypertensive patients were treated with benazepril in a dose of 10-20 mg per day for ten weeks, and ten healthy subjects, matched in age, sex ratio and body mass index (BMI), served as the control group. Before and after the treatment, an oral 75 g glucose tolerance test (OGTT) and insulin release test (IRT) were performed in two groups above, and the blood glucose and serum insulin concentrations at 0, 60, 120 and 180 minutes after glucose load were examined, and the insulin glycoregulatory activity, including insulin sensitivity index (ISI), glucose uptake rate (M), total areas under the glucose and insulin curves during OGTTs (AUCG AUCINS), was calculated. The changes of serum potassium and renal function before and after treatment were observed. It showed that (1) benazepril could reduce blood pressure significantly (SBP decreased from 174.8 +/- 12.0 mmHg to 151.5 +/- 9.0 mmHg, p <0.001; DBP decreased from 108.0 +/- 8.2 mmHg to 95.3 +/- 9.0 mmHg, p <0.001). The total response rate was 86.7%. (2) After treatment with benazepril for ten weeks, the blood glucose and serum insulin concentrations after glucose load and AUCG, AUCINS values in the uremic patients were significantly lower than before treatment, but were still significantly higher than in the controls. The values of ISI and M in the uremic patients after treatment were much higher than before treatment, but were still significantly lower than in the control subjects. (3) The differences of serum potassium and creatinine levels before and after treatment were not significant. These findings indicate that benazepril can not only reduce blood pressure effectively and safely, but also partly improve insulin resistance, hyperinsulinemia and glucose intolerance in uremia.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Clinical treatment planning optimization by Powell's method for gamma unit treatment system.

PURPOSE: This article presents a new optimization method for stereotactic radiosurgery treatment planning for gamma unit treatment system. METHODS AND MATERIALS: The gamma unit has been utilized in stereotactic radiosurgery for about 30 years, but the usual procedure for a physician-physicist team to design a treatment plan is a trial-and-error approach. Isodose curves are viewed on two-dimensional computed tomography (CT) or magnetic resonance (MR) image planes, which is not only time consuming but also seldom achieves the optimal treatment plan, especially when the isocenter weights are regarded. We developed a treatment-planning system on a computer workstation in which Powell's optimization method is realized. The optimization process starts with the initial parameters (the number of isocenters as well as corresponding 3D isocenters' coordinates, collimator sizes, and weight factors) roughly determined by the physician-physicist team. The objective function can be changed to consider protection of sensitive tissues. RESULTS: We use the plan parameters given by a well-trained physician-physicist team, or ones that the author give roughly as the initial parameters for the optimization procedure. Dosimetric results of optimization show a better high dose-volume conformation to the target volume compared to the doctor's plan. CONCLUSION: This method converges quickly and is not sensitive to the initial parameters. It achieves an excellent conformation of the estimated isodose curves with the contours of the target volume. If the initial parameters are varied, there will be a little difference in parameters' configuration, but the dosimetric results proved almost to be the same.

Algorithms↗
PubMed1997

Expression of different levels of enzymes from the Pichia stipitis XYL1 and XYL2 genes in Saccharomyces cerevisiae and its effects on product formation during xylose utilisation.

Saccharomyces cerevisiae was transformed with the Pichia stipitis CBS 6054 XYL1 and XYL2 genes encoding xylose reductase (XR) and xylitol dehydrogenase (XDH) respectively. The XYL1 and XYL2 genes were placed under the control of the alcohol dehydrogenase 1 (ADH1) and phosphoglycerate kinase (PGK1) promoters in the yeast vector YEp24. Different vector constructions were made resulting in different specific activities of XR and XDH. The XR:XDH ratio (ratio of specific enzyme activities) of the transformed S. cerevisiae strains varied from 17.5 to 0.06. In order to enhance xylose utilisation in the XYL1-, XYL2-containing S. cerevisiae strains, the native genes encoding transketolase and transaldolase were also overexpressed. A strain with an XR:XDH ratio of 17.5 formed 0.82 g xylitol/g consumed xylose, whereas a strain with an XR:XDH ratio of 5.0 formed 0.58 g xylitol/g xylose. The strain with an XR:XDH ratio of 0.06, on the other hand, formed no xylitol and less glycerol and acetic acid compared with strains with the higher XR:XDH ratios. In addition, the strain with an XR:XDH ratio of 0.06 produced more ethanol than the other strains.

Aldehyde Reductase↗
PubMed1997

Isolation and characterization of an Arabidopsis biotin carboxylase gene and its promoter.

In the plastids of most plants, acetyl-CoA carboxylase (ACCase; EC 6.4.1.2) is a multisubunit complex consisting of biotin carboxylase (BC), biotin-carboxyl carrier protien (BCCP), and carboxytransferase (alpha-CT, beta-CT) subunits. To better understand the regulation of this enzyme, we have isolated and sequenced a BC genomic clone from Arabidopsis and partially characterized its promoter. Fifteen introns were identified. The deduced amino acid sequence of the mature BC protein is highly conserved between Arabidopsis and tobacco (92.6% identity). BC expression was evaluated using northern blots and BC/GUS fusion constructs in transgenic Arabidopsis. GUS activity in the BC/GUS transgenics as well as transcript level of the native gene were both found to be higher in silique and flower than in root and leaf. Analysis of tobacco suspension cells transformed with truncated BC promoter/GUS gene fusions indicated the region from -140 to +147 contained necessary promoter elements which supported basal gene expression. A positive regulatory region was found to be located between -2100 and -140, whereas a negative element was possibly located in the first intron. In addition, several conserved regulatory elements were identified in the BC promoter. Surprisingly, although BC is a low-abundance protein, the expression of BC/GUS fusion constructs was similar to 35S/GUS constructs.

Amino Acid Sequence↗
PubMed1997

[Effects of spinal cord extract on neurite growth of GABAergic and dynergic neurons of spinal cord in vitro].

We use the crude extract from human fetal spinal cord to study the effect of endogenous substances of the spinal cord on neurite growth of E 12-15 mouse GABAergic and DNYergic neurons of the spinal cord in vitro. The results indicated that the crude extract had no effect on GABAergic neurons but had markedly neurite-promoting effect on DNYergic neurons when the protein concentration of the crude extract was 250 micrograms/ml. It suggests that there are endogenous substances in the crude extract of the human fetal spinal cord, which can promote neurite growth of spinal cord neurons and this effect is neuron type specific at particular embryonic age.

Animals↗
PubMed1997

[Changes in membrane potential of cultured mouse neuron during mitosis].

Primarily cultured dorsal root ganglion cells and olfactory bulb cells were dissected from 12 to 14-d-old fetal C57 BL/6 J mice. After the cells were cultured for about two weeks, the growing status of cells were observed and the membrane potentials(MP) were recorded. The results show that mean value of the MP in anaphase was -68 +/- 3.1 mV (SE, n = 3), same as in interphase: Beginning from telophase, the cell membrane in the equator contracted gradually to become a concave ditch, and the MP decreased obviously, the mean value was -23.3 +/- 3.3 mV (SE, n = 6). After this, MP recovered gradually, till it divided into two sister cells. MP which were recorded separately in two sister cells were similar. But usually MP did not recovered to their normal values immediately.

Animals↗