Biomedical subjects
Publications and source records attributed to X Wen.
Atmospheric argon microwave-induced plasma (Ar-MIP) sustained by a surfatron was obtained. Emission spectra and characteristics of argon metastable (1Sj) were studied with an optical multichannel analyer (OMA-3, 1460) under different experimental condition. Excitation mechanism of the plasma was discussed.
Simple optical multichannel analyzer (OMA) system which is formed by ordinary one dimension CCD camera, spectrograph and microcomputer was introduced in this paper. Spectrochemical analysis feasible of this OMA system was studied. The applied software programed, by us can realize wavelength calibration, spectral line identification and give out automatically the results of qualitative and semidefinite quantity analysis.
We measured venous blood concentrations of lidocaine in 15 patients undergoing lower abdominal or extremity surgery after epidural injection of lidocaine. Patients were divided into either an infusion group (Group I, n = 6) or a bolus injection group (Group II, n = 9). We administered 15 ml of 2% lidocaine into the epidural space at 1 mL/min in Group I and at 1 mL/3 in Group II. Venous blood was drawn at 3, 6, 9, 12, 15, 18, 21, 30, 60, and 90 min after injection for measurement of plasma lidocaine concentrations. The peak plasma concentration (Cmax) of lidocaine in Group I was significantly less than that in Group II (P < 0.0005). We conclude that slow epidural infusion can produce a lower Cmax of lidocaine compared with that of a bolus administration and thereby decrease the potential for systemic toxicity of the local anesthetic.
By means of electrochemical and quantitative histomorphometric methods, the corrosion resistance and tissue biocompatibility of Ti50Ni50 and Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) were investigated. It is discovered that the repassivation potential of Ti50Ni50-xCux (x = 2, 4, 6, 8) alloys is about 200 mV higher than that of Ti50Ni50 alloy. Namely, the addition of Cu raises the repassivation potential of TiNi shape memory alloys and improves their corrosion resistance. Pitting potentials of Ti50Ni50 and Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) alloys increase with solution pH value, but the repassivation potentials keep constant. The adding of Cu has no obvious influence on pitting potential (Epit) of TiNi alloys, meanwhile, the corrosion potential and corrosion rate of Ti50Ni50-xCux (x = 1, 2, 4, 6, 8) alloys are irrelevant to its Cu content and the values are almost the same as those of TiNi alloys. The connective tissue layer covering the plates is statistically significantly thicker for Ti50Ni42Cu8 plates (p < 0.05) than that of Ti50Ni50, Ti50Ni48Cu2, Ti50Ni44Cu6 plates after one month. The numbers of connective tissue cells, polynucleated cells, macrophages and round cells are higher for Ti50Ni42Cu8 plates than those of the other three types of plates, but no statistically significant differences are detected. There are no significant differences on tissue reaction parameters after two and three months among four alloys. After one, two and three months implantation, no corrosion is observed on the plates surfaces. A preliminary conclusion can be drawn that Ti50Ni50-xCux (x = 2, 6, 8) shape memory alloys have good biocompatibility.
As for bio-effect of microrough surface of metallic biomaterials, seven aspects are reviewed in this article: i.e., the relationship between microrough surface (MRS) and corrosion resistance, ion release rate; the relationship between MRS and inflammation; the relationship between MRS and epithelium cells, fibroblast cells; the relationship between MRS and soft tissue; the relationship between MRS and bone; the relationship between MRS and blood tissue; the relationship between MRS and microorganism, contamination, decontamination. To sum up, MRS has its advantages in biocompatibility.
In this paper, four aspects of microrough surface of metallic biomaterials are reviewed: the preparation of microrough surface, the technology of surface roughness measurement, the parameters of roughness and the microrough surface bio-effect.
During a productive infection by herpes simplex virus type 1 (HSV-1), ICP4, the major regulatory protein encoded by the alpha4 gene, binds to its transcription initiation site and represses the accumulation of alpha4 RNA. Evidence suggests that the degree of repression by ICP4 is a function of the absolute distance of an ICP4 binding site 3' from a TATA box. However, repression of HSV-1 gene expression by ICP4 through binding sites located 5' of TATA boxes, as in the case of the alpha0 gene, has not been adequately addressed. To this end, recombinant alpha0 promoters with various arrays of ICP4 binding sites flanking the alpha0 TATA box were constructed and recombined into the HSV-1 genome. Our results demonstrate the following. (i) Destruction of the endogenous alphaO ICP4 binding site, located 5' of the TATA box, results in derepression of alpha0 protein and RNA accumulation in infected Vero cells. (ii) The degree of alpha0 derepression is equivalent to that reported for the alpha4 gene following destruction of the ICP4 binding site at the alpha4 mRNA cap site in HSV-1. (iii) Introduction of an ICP4 binding site at the alpha0 mRNA cap site represses the accumulation of alpha0 RNA greater than threefold relative to the wild type. (iv) Changes in the abundance of alpha0 protein and RNA in infected cells do not affect replication or growth of HSV-1 in tissue culture. Our findings are consistent with the conclusion that alpha0 transcription is repressed by ICP4. These results demonstrate that repression by ICP4 can occur through binding sites located 5' of virus gene TATA boxes in HSV-1. Thus, models addressing repression of HSV-1 gene expression by ICP4 should incorporate the role of binding sites located 5', as well as 3', of virus gene TATA boxes.
The mouse is a common model for transgenic manipulation, however, their small size has made hemodynamic study difficult. A noninvasive 10-MHz pulsed Doppler probe was used to measure aortic and mitral flow velocities in anesthetized, intact mice to study the effects of aging and hypethyroidism (induced by thyroxine) one systolic and diastolic cardiac function. In 10 hyperthyroid mice peak aortic velocity (PAV, an index of systolic function) was 34% higher than in 10 control mice (108 +/- 2 vs. 80 +/- 3 cm/s, P < 0.05). The ratio of early to late mitral filling velocity (E/A ratio, an index of diastolic function) was 47% higher (5.6 +/- 0.8 vs. 3.8 +/- 0.2, P < 0.05) in the hyperthyroid mice. In six old (30 mo) mice PAV was similar to eight young (4 mo) mice (73 +/- 3 vs. 75 +/- 3 cm/s), but the E/A ratio was 59% lower (1.8 +/- 0.3 vs. 4.4 +/- 0.4, P < 0.05). Despite a wide range of observed heart rates, the systolic and diastolic parameters of the groups were clearly separated. We conclude that cardiac systolic and diastolic function in mice, measured by pulsed Doppler ultrasound, are similar to larger species both in magnitude and in their response to hyperthyroidism and aging.
In this paper, four aspects of microrough surface of metallic biomaterials are reviewed: i.e., the preparation of microrough surface, the technology of surface roughness measurement, the parameters of roughness and the bio-effect of microrough surface. Microrough surfaces (roughness below 50 microns) are easily prepared and conveniently detected in practice. Microrough surfaces allow early better adhesion of mineral ions or atoms, biomolecules, and cells, form firmer fixation of bone or connective tissue, result in thinner tissue-reaction-layer with inflammatory cells decreased or absent, and prevent microorganism adhesion and plaque accumulation, when compared with the smooth surfaces.
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GABA (gamma-amino butyric acid), a fast-acting synaptic transmitter in the mature CNS, is synthesized from glutamate by GAD (glutamic acid decarboxylase). We have developed an ultrasensitive PCR technique to quantify the expression of GAD-related mRNAs during the development of the rat cervical spinal cord and have localized them using in situ hybridization. GAD65, GAD67, and an alternatively spliced variant of GAD67, EP10, were quantified each day from embryonic (E) day 11 through E21, and at postnatal days 0, 7, 14, and adult. GAD65 and GAD67 mRNAs were detected at E11 and increased exponentially over three orders of magnitude during embryonic development, then declined approximately threefold in the first-2 postnatal weeks. While the exponential growth phase coincided with the progressive appearance of GAD67 in situ signals in both the ventral and dorsal cord, the postnatal decline coincided with the virtual disappearance of expression in the ventral region. EP10 expression was prominent in the embryo, then declined markedly together with the mRNA encoding the neuroepithelial stem cell marker, nestin. The concerted appearance of GAD-related mRNAs paralleled transcripts encoding neuronal markers (light and heavy neurofilaments) and also closely correlated with the expression of GABA, mRNAs encoding GABAA receptor subunits, and depolarizing responses to GABA. We have used the results on GAD-related mRNA expressions to formulate a simple, minimal mathematical model that accounts for their kinetics in terms of positive and negative feedback loops.
Using purified rabbit polyclonal antibodies to SEA, avidin-biotin system and capture ELISA technique, we observed the dynamic changes in the level of the circulating soluble egg antigen-antibody complex (SEAIC) in murine sera at various weeks post infection. Simultaneously, the diameter and area of liver egg granuloma were measured by using profile analytical technique. Serum SEAIC was first detected 4 weeks post infection (p.i.), reaching peak level at 6-7th week, and then gradually dropped, and maintained at moderately high level till the end of the observation (12 weeks p.i.). Schistosome eggs appeared in liver tissue at 4 weeks p.i. No egg granuloma could be found until 6 weeks p.i. The peak of the average diameter and area of liver egg granuloma was noted at 7 weeks p.i., then dropped gradually. Its dynamic changes were consistent with that of the serum SEAIC level. It is therefore suggested that the serum SEAIC level could be a reference index reflecting the extent of the pathological changes of the liver. Moreover, SEAIC might play an important role in the pathogenesis of schistosomiasis japonica.
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Two samples of births were used to examine the effect of son preference and population policy on sex ratios in Hebei and Shaanxi provinces of China. The results from all births to women aged 15-49 in the 1985 In-Depth Fertility Survey indicated a strong son preference but no clear policy impact on sex ratios at different birth orders. In a sample of selected births during 1975-84 to women aged 40 or under, the mixed influences of son preference and population policy were clearly reflected in the high and rising overall ratios at birth, and the increasing sex ratios with parity. Possible explanations for these findings are discussed.
The foreign body in the eye complicated with traumatic cataract is one of the common causes of blindness. The rate of blindness ranges from 20% to 48.9%. This paper analyses combined operation for 88 cases of foreign body in the eye with traumatic cataract. The visual acuity below 0.05 accounted for 85.2% of the cases before operation and reduced to 27.3% after operation. Postoperatively, the corrected visual acuities were from 0.06 to 1.5 in 73.3% of the cases and 0.6 to 1.5 in 22.7% respectively. The patients should be treated with combined operation earlier. The way of operation depends on the property and the location of foreign body and the situation of lens. Chinese-Western medicine treatment should be used postoperatively to control the tissue response. Combined operation can improve the effect, reduce the complication, the number of operation and decrease medical expenses.
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Respiration of fat body (Periplaneta americana) mitochondria is increased by pretreatment of the tissue with corpus cardiacum (CC) extract. The magnitude of the increase depends on the type of substrate supplied for oxidation. With 5 mM pyruvate the respiration increased 22%, decreasing to 0 with 1 mM pyruvate. In contrast, 50 microM and 0.2 mM palmitic acid supported an increase in CC-stimulated respiration of 14 and 44%, respectively. Unlike crude CC extract, the synthetic hyperglycemic peptides CCI and CCII failed to alter the respiratory activity of fat body mitochondria. In common with the action of CC extract pretreatment of the fat body in vitro with 10(-5) M cyclic AMP, 10(-5) M 8-bromo-cyclic AMP, or 10(-5) M forskolin increased mitochondrial respiration approximately 30%. Octopamine (10(-4) M) elicited a response similar to that obtained with CC extract. Neither 10(-5) M cyclic AMP nor 10(-5) M 8-bromo-cyclic AMP stimulated respiration when applied directly to the mitochondria. These results suggest that the factor in CC extract manifests its effect intracellularly through the activation of a cyclic AMP-dependent protein kinase. This interpretation is also based on the finding that diamide, an inhibitor of protein kinase, inhibits CC-dependent and cyclic AMP-dependent mitochondrial respiration. The physiological role of the CC factor responsible is not known.
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