Biomedical subjects

X Ma

Publications and source records attributed to X Ma.

At least 307 records · Page 17Linked to original sources

PubMed1996

[Fetal erythroblasts from maternal blood for prenatal genetic diagnosis].

OBJECTIVE: To study fetal erythroblasts (FE) from maternal peripheral blood for the diagnosis of fetal aneuploidies. METHODS: FE expressing the glycophorin A(GPA) were isolated from 13 pregnant women with male fetus (8-14 w) by fluorescence-activated cell sorting(FACS), FE were identified by oligonucleotide primed in situ labelling (PRINS) with Y centromeric satellite DNA primer. The concentration of pregnancy-associated plasma protein A (PAPP-A) was measured by enzyme-labelled immunosorbent assay (ELISA) in serum samples of 41 normal pregnant women (8-14 w). In 5 pregnant women suspicious of fetal Down's syndrome (10-13 w) the serum and FE were examined by PAPP-A, GPA/FACS and PRINS with 21 chromosome centrometric primer. RESULTS: Detection of flow sorted FE from 13 pregnant women by Y primer showed 14.5% of GPA positive signal. There was no difference in serum level of PAPP-A between 5 pregnant women and 41 normal controls, and all GPA positive cell nuclei of the 5 cases displayed two signals with 21 chromosome. CONCLUSION: Measurement of fetal erythroblasts from maternal blood for the diagnosis of genetic fetal aneuploidies is a promising non-invasive, rapid and reliable technique.

Adult↗

PubMed1996

[Substance P in synovial fluid in patients with temporomandibular joint dysfunction syndrome].

Radioimmunoassay technique was used to measure substance P levels in synovial fluid samples from thirty patients with temporomandibular joint dysfunction syndrome (TMJDS). Twenty-four samples (80%) were found to have substance P. Concentrations of substance P in the synovial fluid from patients with painful TMJDS were higher than those patients without pain (P < 0.05). The study supported the evidence for the secondary synovitis in painful TMJDS, and suggested that the nervous system play a role in the pathophysiology of TMJDS.

Adolescent↗

PubMed1996

[Clinical and radiographic study of Sjögren syndrome in children].

Eight cases of Sjögren syndrome in children were presented. Recurrent swelling of salivary glands was shown to be predominant findings in children with Sjögren syndrome. It was first reported that "lace-like" appearance of main duct was of great value in sialographic diagnosis of Sjögren syndrome in children. The differentiation between Sjögren syndrome and recurrent parotitis in children was discussed.

Adolescent↗

PubMed1996

[Expression of tissue-type plasminogen activator (t-PA) in smooth muscle cells of injured iliac arteries in rabbits].

To investigate the mechanism of atherogenesis and development of restenosis following angioplasty, the expression of t-PA in SMC at different intervals after the arterial injury was measured by morphological analysis, plasmin generation assay and in situ hybridization. t-PA activity of the iliac arteries was noticed to be significantly increased on the 4th day after injury, signalling the commencement of SMC migration from the media to intima, t-PA activity then decreased to approximately the normal level on the 7th day. Results from in situ hybridization also showed that the expression of t-PA mRNA in the intima and media increased significantly on the 4th day after the arterial injury, by the 7th day, t-PA mRNA was detected only in SMC located adjacent to the internal elastic lamina. These results suggest that t-PA might play an important role in SMC proliferation and migration following arterial injury.

Angioplasty, Balloon, Coronary↗

PubMed1996

Expression of tissue-type plasminogen activator in smooth muscle cells of injured iliac arteries in rabbits.

In this experiment, expression of tissue-type plasminogen activator (t-PA) in smooth muscle cells (SMCs) was measured at different intervals after the arterial injury. In the normal iliac arteries, only low levels of t-PA activity were estimated. t-PA activity in extracts of the iliac arteries increased significantly at the 4th day after the injury, equivalent to the process that SMCs migrated from the media to the intima, and the t-PA activity was then decreased approximately to the normal level at the 7th day. Coexistent to the above data, results from in situ hybridization showed that the expression of t-PA mRNA in the intima as well as media increased also significantly at the 4th day after the arterial injury, and at the 7th day, t-PA mRNA was detected only in those SMCs locating closely adjacent to the internal elastic lamina. These results suggest that t-PA might play an important role in SMC migration following endothelial injury, and antagonism of t-PA expression and/or activity within the vessel wall might be helpful in intervening the development of restenosis following angioplasty.

Angioplasty, Balloon↗

PubMed1996

[Magnetic resonance imaging of the TMJ disc in asymptomatic volunteers].

To determine whether disc displacement of temporomandibular joint exists in asymptomatic subjects in China, we examined fifty temporomandibular joints (TMJs) of 39 asymptomatic volunteers by magnetic resonance imaging (MRI). All subjects had no history of TMJ pain, joint noise, deviation, and opening limitation, Oblique sagittal and coronal MR images were obtained by scanning perpendicular and paralell to the longitudinal axis of the condyle respectively. MR imaging depicted anterior, medial and rotational disc displacement in 32% of the asymptomatic joints. Disc displacement in asymptomatic subjects may be a predisposing factor of TMJ dysfunction.

Adolescent↗

PubMed1996

[An electromyographic study of the exposed lateral pterygoid muscle in monkey].

The purpose of the present study is to observe the electromyogram (EGM) manifestations of the lateral pterygoid muscle (LPM) in monkey during mouth opening and closing movements. The lateral pterygoid muscle of five healthy monkeys (macaques) was exposed by operation under general anesthsia and the electropolar needles were placed into the superior and inferior head of LPM respectively. The EMG manifestations of the superior and inferior head of LPM were recorded by O.T.E. Biomedica EMG Recorder during the natural condition and the movements of opening and closing mouth after complete recovery from anesthesia. It has been found that the two heads acted synergistically only in opening movement and no activity was noted in closing movement. This finding disagrees with the previous viewpoint that the function of the superior and inferior head of LPM is independent.

Animals↗

PubMed1996

[Radiographic findings in osteoarthrosis of temporomandibular joint in relation to its pathologic changes].

We analysed the results of the central standard lateral tomographic findings and the macroscopic/microscopic observations on the middle portion of the autopsy materials of 84 temporomandibular joints. It was not suitable to differentiate remodeling and osteoarthrosis of the temporomandibular joint only by whether the surface articular zone of the articular cartilage is intact or not. The early changes of osteoarthrosis could occur in the interface of the bone-cartilage except occuring in the articular zone, even though the surface articular zone was intact. Therefore, we suggest that the definition of osteoarthrosis should be wider. Histopathologic observations proved that the definte radiographic signs, such as sclerosis, erosion, pseudocyst, osteophyte and so on showed on the lateral tomographs were credible signs in the diagnosis of osteoarthrosis.

Aged↗

PubMed1995

Stimulatory and inhibitory effects of interleukin (IL)-4 and IL-13 on the production of cytokines by human peripheral blood mononuclear cells: priming for IL-12 and tumor necrosis factor alpha production.

The production of cytokines in monocytes/macrophages is regulated by several different cytokines that have activating or inhibitory effects. Interleukin (IL)-10, IL-4, IL-13, and transforming growth factor (TGF)-beta are usually considered to be the most important macrophage-deactivating factors, with inhibitory effects on cytokine production. Unlike IL-10 and TGF-beta, which appear to act as downmodulators of many phagocytic cell functions, the mode of action of IL-4 and IL-13 is more complex. Addition of IL-4 and IL-13 to peripheral blood mononuclear cell (PBMC) cultures inhibited production of IL-12, tumor necrosis factor (TNF)-alpha, IL-10, and IL-1 beta induced by lipopolysaccharide (LPS) or Staphylococcus aureus added simultaneously with the cytokines. However, pretreatment of PBMC with IL-4 or IL-13 for > or = 20 h enhanced the production of IL-12 and TNF-alpha in response to LPS or S. aureus several fold in these cells; this IL-4-induced priming for the two cytokines was inhibited by anti-IL-4 neutralizing antibodies. IL-4 priming also enhanced the accumulation of IL-12 and TNF-alpha mRNA induced by LPS and S. aureus. The enhanced accumulation of transcripts for the IL-12 p35 and p40 chains by IL-4 priming was reflected in enhanced secretion of both the IL-12 free p40 chain and the p70 heterodimer. These results suggest an unexpected complexity in the regulatory role of IL-4 and IL-13 in immune responses.

Animals↗

PubMed1995

Interleukin-12 production by human polymorphonuclear leukocytes.

Human polymorphonuclear leukocytes (PMN) stimulated by lipopolysaccharide (LPS) produce interleukin-12 (IL-12). Both the free IL-12 p40 chain and minute amounts of the biologically active IL-12 p70 heterodimers are produced by PMN. Interferon-gamma (IFN-gamma) enhanced the LPS-induced secretion of both the free IL-12 p40 chain and the p70 heterodimer by approximately fivefold. As observed for other IL-12-producing cell types, the ratio of free p40 chain to p70 heterodimer secreted by LPS-stimulated PMN was approximately 20:1. LPS induced a 100-fold increase of IL-12 p40 mRNA, but had minimal effect on p35 mRNA accumulation. IFN-gamma enhanced the LPS-induced accumulation of p40 mRNA and directly induced a several-fold increase in the accumulation of p35 mRNA. Therefore, the combined effect of LPS and IFN-gamma induced sufficient expression of both p40 and p35 to attain production of the biologically active p70 heterodimer at physiologically relevant concentrations. The ratio between p40 and p35 mRNA abundance in PMN stimulated with both LPS and IFN-gamma was approximately 200:1, explaining the secretion of the free p40 chain in much higher concentrations than the p70 heterodimer. IL-10, an inhibitor of the production of various cytokines in PMN, also suppressed IL-12 mRNA accumulation and secretion by PMN. Because of the important immunoregulatory function of IL-12, in particular induction of IFN-gamma production and facilitation of T helper cell type 1 response, the ability of PMN to produce IL-12 suggests that neutrophils may play an active role in the regulatory interaction between innate resistance and adaptive immunity.

Blotting, Northern↗

PubMed1995

Tumor necrosis factor in synovial fluid of patients with temporomandibular disorders.

PURPOSE: To assess tumor necrosis factor (TNF) activity in synovial fluid from patients with temporomandibular disorders. PATIENTS AND METHODS: Tumor necrosis factor (TNF) activity in synovial fluid from 27 patients with temporomandibular disorders (TMDs) was studied using the MTT tetrazolium WEHI 164 clone 13 cell cytotoxicity assay. RESULTS: No detectable TNF levels were found in five patients with a masticatory muscle disorder, but elevated TNF levels were found in 5 of 11 patients with TMJ disc displacement, and in 9 of 11 patients with degenerative joint disease. CONCLUSION: The findings of biologically active TNF in the synovial fluid of these patients suggests that it may play a role in the pathogenesis of certain temporomandibular disorders.

Adolescent↗

PubMed1995

Magnetic resonance imaging verification of a multi-compartment perfusion model for a chromatography gel phantom.

A model of MRI signal intensity was developed for chromatography column phantoms containing Sephadex gels, which were used to simulate tissue perfusion and the exchange of protons between extravascular and intravascular tissue compartments. Computer simulations of two-compartment and three-compartment models were compared in experiments that used two chromatography columns. One column contained a Sephadex G-25 gel that had a smaller pore size and a slower rate of exchange between extrabead and intrabead compartments than did a second column, which contained a G-50 gel with a larger pore size. In both columns the beads were of approximately the same size to simulate the same ratio of intrabead volume to extrabead volume. Slice-selective spin-echo experiments were performed with the columns oriented parallel to each other in a 1.5 T imager and parallel to the magnetic field, with water flowing through each column perpendicular to the slice at mean flow velocities ranging between 0 and 0.66 mm/s. The results of the experiments agreed with computer simulations, which showed that the MRI signal intensity in the perfused columns is a function of the rate of exchange between extrabead and intrabead compartments. The exchange process modifies the transit time of protons passing through an excited region. The simulations also showed that both two-compartment and three-compartment models could be used to fit the experimental data. Experiments with chromatography gel columns are a preliminary investigation into the potential of using MRI to measure the exchange between extravascular and intravascular compartments of endogenous protons during blood perfusion of biological tissue.

Body Fluid Compartments↗

PubMed1995

Milk composition in women from five different regions of China: the great diversity of milk fatty acids.

Human milk samples were obtained from 146 lactating women living in five distinct geographic regions of the People's Republic of China. The regions were characterized as follows: pastoral, rural, urban 1, urban 2, and marine. Dietary information obtained on a subsample of women providing milk suggested distinct differences in the food availability in the five regions and the habitual diets of the lactating women studied. The milk concentration of docosahexaenoic acid (DHA) varied greatly (g/100 g total fatty acids): 0.44 +/- 0.29 (pastoral), 0.68 +/- 0.29 (rural), 0.88 +/- 0.34 (urban 1), 0.82 +/- 0.35 (urban 2), and 2.78 +/- 1.20 (marine region). Docosahexaenoic acid is critical for brain and retina development in the infant. Milk arachidonic acid (AA) ranged from 0.80 +/- 0.14 (rural) to 1.17 +/- 0.33 and 1.22 +/- 0.32 g/100 g fatty acids from the marine and pastoral regions. Arachidonic acid is associated with infant growth. The AA to DHA ratio (g/g) was highly variable also: 2.77 (pastoral), 1.18 (rural), 1.01 (urban 1), 1.23 (urban 2), and 0.42 (marine). The DHA concentration found in the milk of women from the marine region was twice as high as any reported previously, but was in a range similar to the amounts found in the milk of women fed fish oil. Seafood consumption by the women residing in the marine region is a likely contributor to the DHA concentration in their milk. These data illustrate the heterogeneity of the fatty acid composition of human milk and suggest a great influence of geography and the maternal diet on concentrations of DHA and AA in human milk.

Adult↗

PubMed1995

Interleukin-6 in synovial fluid and HLA-DR expression in synovium from patients with temporomandibular disorders.

Interleukin-6-dependent mouse hybridoma cell line KD83 was used to test the biologic activity of interleukin-6 in synovial fluid from 37 patients with temporomandibular disorders. The results showed that the interleukin-6 level was greater than 100 U/mL in 13 of 18 patients with degenerative joint disease and in five of 12 patients with temporomandibular disc displacement. However, the interleukin-6 level was less than 100 U/mL (range, 20 to 75 U/mL) in all patients with masticatory muscle disorder. It has been found that degenerative joint disease tends to have acute and chronic stages, and interleukin-6 activity was probably related to the acute stage in the patients. Histologic studies of the synovium from seven patients with degenerative joint disease showed a variable degree of hyperplasia of the synovial lining cells and chronic inflammation in five of eight specimens. Immunostaining studies clearly showed the presence of significantly more HLA-DR-expressing cells (human leukocyte antigen-D-related) in synovium. Although it is unlikely that immune responses play an important primary role in initiating synovial inflammation and cartilage destruction, immune reactions may be one important factor in the maintenance and severity of some patients with temporomandibular disorders.

Adolescent↗

PubMed1995

[Gallbladder contraction and microscopi observation of the gallbladder wall in gallstone patients].

On the basis of oral cholecystography (OCG), we selected gallstone patients for nontoperative intervention. Their gallbladder function was considered as normal when gallbladder contracted over 50%-75% after a fat meal at 1 hour. We collected 99 gallstone patients and 19 normal controls; gallbladder function was normal in 77 patients and poor in 22. After a fat meal gallbladder volumes were calculated by B ultrasonography. The results showed that both fasting and residual volume in patients with so-called normal contraction were significantly greater than that in the controls (P < 0.001), though the contraction rate was not different. The combination of gallbladder contraction rate measurement and residual volume calculation by ultrasonography was superior over traditional OCG.

Adult↗

PubMed1995

Overexpression of human apolipoprotein A-I in transgenic rats and the hyperlipoproteinemia associated with experimental nephrosis.

Hyperlipoproteinemia contributes both to kidney disease progression and the development of atherosclerosis. Elevated high density lipoprotein cholesterol and apolipoprotein A-I (apoA-I) serum levels are independent factors protective against the atherosclerotic process. We examined the effects in a transgenic rat model of human apoA-I expression on the hyperlipoproteinemia and edema after puromycin aminonucleoside-induced nephrosis in three groups of animals: low line (TgR[hAI]low, human plasma apoA-I = 16.0 mg/dl); high line (TgR[hAI]high, 284 mg/dl); and non-transgenic litter mates (TgR[hAI]non). Nephrosis increased total plasma apoA-I levels 2-fold in TgR[hAI]non rats (75 vs. 162 mg/dl) and 4-fold in the TgR[hAI]low (97 vs. 458 mg/dl) and TgR[hAI]high rats (356 vs. 1,346 mg/dl). In both transgenic lines, this increase was due mainly to elevations of serum human apoA-I. The hepatic steady-state levels of rat apoA-I mRNA increased 5- to 7-fold in all three groups, while human apoA-I mRNA levels increased 21- and 65-fold in the low and high expressing groups, respectively, indicating a different degree of responsiveness of the rat and human genes. While nephrotic TgR[hAI]non and TgR[hAI]low rats showed severe hyperlipoproteinemia and edema, much lower levels of edema and of serum triglycerides, phospholipids, and cholesterol were seen in the TgR[hAI]high group. Urinary excretion of apoA-I, phospholipids, and cholesterol was significantly increased in the TgR[hAI]high group, indicating this as one possible mechanism for the relatively lower serum levels of these lipids. We conclude that the human apoA-I gene is responsive to nephrosis and that human apoA-I-transgenic rats with this syndrome provide an animal model for the study of human high density lipoprotein and apoA-I metabolism.

Animals↗

PubMed1995

[Repair of scalp defects with skull exposure].

The methods for repairing scalp defects and skull exposure are introduced. From 1980 to 1991, 9 cases of scalp defects and skull exposure from injury or tumor extirpation were treated with free omentum transfer with split skin graft, free flap or axial flap transfer. The surgical procedure was described in detail. For the whole defect of scalp with skull exposure the authors consider the free anterior-lateral femoral flap more appropriate and suggest that the free omentum flap be avoided as far as possible.

Adolescent↗

PubMed1995

[Evaluation of radiographic diagnosis on osteoarthrosis of the temporomandibular joint].

84 cadavers' temporomandibular joints were used to compare the results shown in standard lateral tomographs and Schuller's position films with gross views on the bone and cartilage changes. The results and conclusions were as follows: (1) The positive rates of the radiographic evidences were associated with the degrees of the macroscopic lesions. The more severe the macroscopic lesion, the higher the positive rate of radiographic evidence. (2) The sensitivity of radiographic examination was positively correlated with the extent of the macroscopic lesion. So, the negative predictive value was. However, the specificity and the positive predictive value of the radiographic examination were negatively correlated with macroscopic change index. It has been found that the more the extent of osteoarthrosis changes, the higher the sensitivity of radiographic examination; the higher the negative predictive values, the higher the positive rate of radiographic evidence, and the lower the underdiagnosis rate was. Meanwhile, the more the extent of bone pathological changes in the joint, the lower specificity of the radiographic examination, and the lower the positive predictive values and the misdiagnosis is increased. (3) The radiographic diagnostic value based on the standard latreal tomographs of TMJ, Schuller's position films or based on the both methods was not satisfied. Its underdiagnosis rate was higher. Therefore, we suggest that multiple-layers lateral tomography should be widely used in clinical practice.

Aged↗