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Biomedical subjects

W Luo

Publications and source records attributed to W Luo.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Surgical treatment of primary mediastinal tumor: a report of 90 cases].

In the past 22 years 90 cases of pathologically confirmed primary mediastinal tumors (PMT) were surgically treated. Of these 90 cases, there were 38 thymomas (42.3%), 19 teratoblastomas (21.2%), 9 neurofibromas (10.0%) and 24 others (26.5%). Radical excision was performed in 70 (77.8%), palliative excision in 6 (6.7%), exploratory thoracotomy in 12 (13.3%). Postoperative death occurred in 2 (2.2%). No relapse was reported in patients who had received radical excision during the follow-up period of 3 months to 13 years. Besides careful history taking and physical examination, X-ray examinations of the chest, particularly CT scan were valuable in the diagnosis and differential diagnosis of PMT. Difficulties in diagnosis were due to unusual pathological changes and clinical manifestations. Due precautionary measures should be taken to avoid injury to the heart, major blood vessels and the spinal cord. Cord injury was the consequence of direct operative trauma, compression due to intraspinal hemorrhage, and/or operative interruption of blood supply.

Adolescent↗
PubMed1996

The role of human leukocyte antigen in susceptibility and clinical manifestations of sarcoidosis.

OBJECTIVE: To investigate the correlation of human leukocyte antigen (HLA) with susceptibility and clinical manifestations of sarcoidosis. MATERIAL AND METHODS: Fifty-five patients with sarcoidosis and one hundred and six normal subjects were investigated. Genomic DNAs were purified using the proteinase K-phenol extraction method. DNA samples were amplified by the polymerase chain reaction (PCR) procedure using the DRB1 group specific primer pairs. RESULTS: The gene frequency of HLA-DR5 increased significantly in patients with sarcoidosis (P < 0.01), and HLA-DR7 decreased (P < 0.05). Gene frequencies of HLA-DR9 and HLA-DR5 increased remarkably in male patients and in patients with stage I and stage IIa, respectively (both P < 0.05). CONCLUSIONS: It is suggested that HLA-DR gene might contribute to the susceptibility as well as various clinical manifestations of sarcoidosis.

Adult↗
PubMed1996

Steroid-resistant asthma immunologic characteristics.

OBJECTIVE: To investigate whether persistent T lymphocyte activation is a feature of steroid-resistant (SR) asthma and to study the inhibitory effects of dexamethasone and other immuno-inhibiting agents on PHA-induced proliferation of peripheral blood T lymphocytes from SR and steroid-sensitive (SS) asthmatics. MATERIAL AND METHODS: 15 SR and 15 SS asthmatics were studied. Serum levels of soluble interleukin-2 receptor (sIL-2R) were measured before and after prednisone therapy by an enzyme-linked immunosorbent assay. PHA-driven proliferative assay was performed to evaluate inhibition of T lymphocyte proliferation. RESULTS: Serum levels of sIL-2R were elevated in both patients with SR and SS asthma as compared with normal controls (P < 0.001). After a 7-day course of prednisone (20 mg/day), serum levels of sIL-2R decreased significantly in SS asthmatics (P < 0.001) but not in SR asthmatics (P > 0.1). Proliferation of T lymphocytes from the sensitive but not the resistant asthmatics was significantly (P < 0.002) inhibited by dexamethasone (10 mol/L), reflecting a shift of the dose-response curve. In contrast, oxymatrine and thymus-derived immunosuppressors inhibited proliferation of T lymphocytes to a similar degree between SR and SS asthmatics. CONCLUSIONS: The results suggest that persistent T lymphocyte activation due to a relative insensitivity of the cells to glucocorticoids is a feature of SR asthma. Immuno-inhibiting agents other than glucocorticoids may be of therapeutic benefit in patients with SR asthma.

Adult↗
PubMed1996

Relaxant effects of vasoactive intestinal peptide on pulmonary artery in chronically hypoxic rats.

The object of this study is to investigate the effect of VIP on pulmonary artery of chronically hypoxic rats. It was shown that chronic hypoxia depressed significantly pulmonary artery relaxation induced by VIP as compared with those of control (P < 0.001). The vascular relaxation of both groups was correlated with concentration of VIP. In addition, the relaxant effect of VIP on pulmonary arteries in rats was endothelium-independent, and was not prevented by indomethacin or nordihydroguaiaretic acid, but was abolished completely by methylene blue. These results suggest that the lower relaxation of pulmonary artery in rats might not be due to the endothelial injury caused by chronic hypoxia, and chronic hypoxia may inhibit directly the soluble guanylate cyclase in vascular smooth muscle cells involved in synthesis of cGMP and thus reduced the sensitivity and reactivity of pulmonary artery to VIP.

Animals↗
PubMed1996

Detection of Borrelia burgdorferi DNA in granulomatous tissues from patients with sarcoidosis using polymerase chain reaction in situ technique.

To investigate the correlation between sarcoidosis and Borrelia burgdorferi (Bb) infection, flagella DNA of Bb were detected in 23 granulomatous tissue specimens from patients with confirmed sarcoidosis using polymerase chain reaction in situ technique (in situ PCR) and the antibodies to Bb were examined in 55 serum samples obtained from the patients by indirect immunoflurescence assays. Our data presented that: (1) None of granulomatous tissues was found to have Bb DNA in 23 tissue samples. (2) Thirty of 55 (54.6%) patients with sarcoidosis were found antibodies to Bb positive, in contrast, six of 60 (10%) normal subjects had antibodies against Bb, the positive rate was remarkably higher in patient group than that in healthy group (P < 0.005). The results suggest that Bb might not be the causative agent of sarcoidosis, the elevated titres of serum antibodies against Bb in patients with sarcoidosis is a nonspecific response.

Antibodies, Bacterial↗
PubMed1996

[Synthesis and distribution of endothelin in rats with pulmonary hypertension induced by chronic hypoxia].

OBJECTIVE: To study the synthesis and distribution of endothelin (ET) in the rat model of pulmonary hypertension (PH). METHOD: By chronic hypobaric hypoxia (10%-10.5% O2, 4-18 d), a stable rat model of PH was established. The plasma ET level in the rat was measured by radioimmunoassay and the ET-like immunoreactivity in the rat's lung tissue was observed morphologically by immunohistochemical staining. RESULTS: The concentrations of plasma ET were significantly higher in the hypoxic rat model than in control animals (P < 0.01), but there were no significant differences in different time groups of the hypoxic rats (P > 0.05). ET's synthesis was mostly localized within pulmonary vascular vessels sharply contrasted with normal rats in which there were little or no ET staining. CONCLUSION: The results suggested that hypoxia might be the main reason for promoting ET's synthesis and release.

Animals↗
PubMed1996

[Effects of L-arginine on acute hypoxic pulmonary hypertension and production of endothelin-1 in vivo and in cultured endothelial cells].

This study is aimed to investigate the effects of L-arginine, a precursor of the formation of nitric oxide, on acute hypoxic pulmonary hypertension in vivo and on production of endothelin-1 both in vivo and in cultured endothelial cells. In mechanically ventilated anesthetized dogs (n = 7), L-arginine (0.5 g/kg) reduced the mean pulmonary arterial pressure and femoral arterial pressure during hypoxic ventilation and its action lasted for about 30 minutes. Meanwhile, plasma endothelin-1 in the pulmonary and femoral artery had no remarkable change. In cultured endothelial cells from umbilical veins, different concentrations of L-arginine had no influence on endothelin-1 level of culture medium in 4 or 24 hours after the addition of L-arginine. These results indicate that L arginine can decrease the pulmonary arterial pressure during acute hypoxia, which may be associated with the increase of nitric oxide production.

Animals↗
PubMed1996

[Plasma endothelin-1 and pulmonary hemodynamics at pre-or post exercise in chronic obstructive pulmonary disease].

OBJECTIVE: To investigate whether plasma endothelin-1 (ET-1) affects the pathologic physiologic process of pulmonary hypertension (PH) secondary to chronic obstructive pulmonary disease (COPD). METHODS: Forty-six patients with COPD who underwent right float-assisted cardiac cather examination and a supine ergometer exercise test were classified into 3 groups, that is, group A with PH, group B with latent PH and group C without PH. RESULTS: (1) There was a marked higher ET-1 level in femoral arterial plasma than in pulmonary arterial plasma from group A at pre-or post-exercise or group B at post-exercise. (2) Plasma ET-1 levels of A and B groups post-exercise are higher that that in group B post-exercise than that in group C. (3) ET-1 level is also higher in group B post-exercise than that in group C. (4) There was significant correlation between the ET-1 level and mPAP, PVR, PaO2 of group A at pre- and post-exercise or group B at post-exercise. CONCLUSION: These finding suggest a role for ET-1 in regulating pulmonary circulation of PH secondary to COPD).

Aged↗
PubMed1996

[Detection of Borrelia burgdorferi DNA in granulomatous tissues from patients with sarcoidosis using polymerase chain reaction in situ technique].

OBJECTIVE: To investigate the correlation between sarcoidosis and Borrelia burgdorferi (Bb) infection. METHODS: Flagella DNA of Bb were detected in 23 tissue speciments from patients with confirmed sarcoidosis using polymerase chain reaction in situ technique (in situ PCR) and the antibodies to Bb were examined in 55 serum samples obtained from the patients by indirect immunoflurescence assays. RESULTS: (1) None of granulomatous tissues was found to have Bb DNA in 23 tissue samples. (2) 30 of 55 (54.6%) patients with sarcoidosis were found antibodies to Bb positive, in contrast, six of 60 (10%) normal subjects had antibodies against Bb, the positive rate was remarkably higher in patient group than that in healty group (P < 0.005). CONCLUSIONS: Bb might not be the causative agent of sarcoidosis, the elevated titres of serum antibodies against Bb in patients with sarcoidosis is a nonspecific response.

Borrelia burgdorferi Group↗
PubMed1995

Structure and function of C-CAM1: effects of the cytoplasmic domain on cell aggregation.

C-CAMs are epithelial cell-adhesion molecules of the immunoglobulin supergene family with sequences highly homologous to carcinoembryonic antigen (CEA). C-CAMs and their human homologues, biliary glycoproteins, are unique among the CEA-family proteins in that they have cytoplasmic domains. Furthermore, alternative splicing generates C-CAM isoforms with different cytoplasmic domains, suggesting that the cytoplasmic domains of C-CAM may play important roles in regulating the function or functions of C-CAM. By using both sense and antisense approaches, we have shown that C-CAM1 is a tumour suppressor in prostate carcinogenesis. This observation raises the possibility that the cytoplasmic domain of C-CAM1 may be involved in signal transduction or interaction with cytoskeletal elements to elicit the tumour suppressor function. The cytoplasmic domain of C-CAM1 contains several potential phosphorylation sites, including putative consensus sequences for cyclic AMP-dependent kinase and tyrosine kinase. One of the potential tyrosine phosphorylation sites is located within the antigen-receptor homology (ARH) domain. The ARH domain of the membrane-bound IgM molecule is necessary for signal transduction in B-cells. These structural features suggest that the cytoplasmic domain of C-CAM1 may be important for signal transduction. To test this possibility, we generated several site-directed C-CAM1 mutants and tested their ability to support adhesion and their abilities to be phosphorylated in vivo. Results from these studies revealed that Tyr-488 is phosphorylated in vivo. However, replacing this tyrosine with phenylalanine did not significantly compromise its adhesion function. Similarly, Ser and Thr residues are phosphorylated in vivo, but deletion of the potential cyclic AMP-dependent kinase site did not significantly reduce the adhesion function. These results suggest that the kinase phosphorylation sites in the cytoplasmic domain of C-CAM1 are not required for the adhesion function. However, these phosphorylation sites are probably involved in the regulation of C-CAM-mediated signal transduction. Thus, there are probably distinct structural requirements for the adhesion and the signal transduction functions of C-CAM. Incidentally, a C-CAM1 deletion mutant containing a 10-amino-acid cytoplasmic domain was able to support adhesion activity. This is in contrast to our previous finding that a C-CAM isoform, C-CAM3, with a 6-amino-acid cytoplasmic domain could not support cell adhesion. This result indicates that the extra four amino acids, which are absent in C-CAM3 and contain a potential Ser/Thr phosphorylation site, are important for the adhesion function.

Adenosine Triphosphatases↗
PubMed1995

Inhibition of alpha-chymotrypsin with an enzyme-activated n-nitrosoamide: active-site labeling by the naphthylmethyl cation.

alpha-Chymotrypsin was irreversibly inhibited with an enzyme-activated N-nitrosamide inhibitor, N-nitroso-N-(1-naphthylmethyl)-N'-isobutyrylalanine; alkylation of the active-site residues by the naphthylmethyl cation produced in the enzymatic reaction occurred. The inhibited enzyme was reduced and aminoethylated and then subjected to tryptic and chymotryptic digestion. Separation of the digest by reversed-phase HPLC revealed one major new peak relative to that of a control run from the native enzyme. Subsequent amino acid analysis and sequencing along with fast atom bombardment-mass spectrometry measurements indicated that this new peak stemmed from an active-site peptide, Met-192-Leu-199, and that the naphthylmethyl label was attached to the side-chain oxygen of Ser-195. The general approach employed can be applied to labeling active sites of a variety of hydrolytic enzymes.

Alanine↗
PubMed1995

Premature suture closure and ectopic cranial bone in mice expressing Msx2 transgenes in the developing skull.

The coordinate growth of the brain and skull is achieved through a series of interactions between the developing brain, the growing bones of the skull, and the fibrous joints, or sutures, that unite the bones. These interactions couple the expansion of the brain to the growth of the bony plates at the sutures. Craniosynostosis, the premature fusion of the bones of the skull, is a common birth defect (1 in 3000 live births) that disrupts coordinate growth and often results in profoundly abnormal skull shape. Individuals affected with Boston-type craniosynostosis, an autosomal dominant disorder, bear a mutated copy of MSX2, a homeobox gene thought to function in tissue interactions. Here we show that expression of the mouse counterpart of this mutant gene in the developing skulls of transgenic mice causes craniosynostosis and ectopic cranial bone. These mice provide a transgenic model of craniosynostosis as well as a point of entry into the molecular mechanisms that coordinate the growth of the brain and skull.

Animals↗
PubMed1995

Tumor suppressive role of an androgen-regulated epithelial cell adhesion molecule (C-CAM) in prostate carcinoma cell revealed by sense and antisense approaches.

We recently demonstrated that C-CAM, an epithelial-cell adhesion molecule of the immunoglobulin supergene family, could be regulated by androgen and might act as a growth repressor during differentiation of the prostatic epithelium. To define the role of C-CAM in prostatic tumorigenesis, a tumorigenic human prostatic cancer cell line, PC-3, was transfected with an expression plasmid containing C-CAM1 (a C-CAM isoform). Transfected clones showed significantly lower growth rates, reduced anchorage-independent growth, and less tumorigenicity in vivo than control cells. Furthermore, transfection of an antisense vector into a nontumorigenic prostatic epithelial cell line, NbE, resulted in tumor formation in nude mice. Sublines derived from these NbE-induced tumors had lower levels of C-CAM than did control cells. These data suggest that C-CAM1 can function as a tumor suppressor in prostate tumorigenesis.

Adenosine Triphosphatases↗
PubMed1995

Comparison of concentration-time profiles of levobunolol and timolol in anterior and posterior ocular tissues of albino rabbits.

The potential effects of anti-glaucoma drugs, such as levobunolol and timolol, on blood flow in the posterior segment of the eye are of great interest in terms of changes in optic nerve head perfusion and prevention of visual field loss. These effects are related to the rate and extent of their absorption into the site of action. In this study, the concentrations of timolol and levobunolol in the aqueous humor, iris-ciliary body, vitreous humor, choroid-retina, and optic nerve were compared following instillation of a single drop of 0.5% ophthalmic solutions into albino rabbit eyes. Tissue drug and metabolite concentrations were measured by liquid chromatography-mass spectrometry. Dihydrobunolol (DHB) is an equipotent metabolite of levobunolol. In the anterior segment of the eye, levobunolol plus DHB concentrations were higher than timolol concentrations in aqueous humor and were comparable to those of timolol in iris-ciliary body. However, in the choroid-retina and optic nerve, timolol concentrations were greater than those of levobunolol plus DHB. Overall, the study demonstrates comparable concentrations of levobunolol and timolol in the anterior section of the eye. The low availability of levobunolol in the posterior segment as compared to timolol may be a key advantage for levobunolol in producing less adverse effect on blood flow in the choroid-retina and optic nerve.

Absorption↗
PubMed1995

[Reversal of acute hypoxic pulmonary hypertension with inhalation of nitric oxide].

The effect of inhalation of nitric oxide (NO) gas on acute hypoxic pulmonary hypertension was studied. Eighteen mongrel dogs were divided into two groups: hypoxic control group (FIO2 = 11%, n = 10) and NO inhalation group (FIO2 = 11%, NO inspiratory concentration = 44 ppm, n = 8). In the control group, the increase percent of mean pulmonary arterial pressure (mPAP) was 30.6% +/- 5.5%, 47.8% +/- 11.3%, 46.0% +/- 9.3%, 37.0% +/- 6.3% respectively at 5th, 15th, 30th and 60th minute after hypoxic ventilation. In the NO inhalation group, mPAP increment was 4.6% +/- 3.7%, 0.5% +/- 6.0%, 0.7% +/- 6.8%, 7.2% +/- 6.1%, respectively (all P < 0.01, compared with the control group). Inhaled nitric oxide also reduced the pulmonary vascular resistance significantly during hypoxic ventilation, but it had no remarkable effect on the systemic arterial pressure and vascular resistance. These results indicated that inhalation of nitric oxide gas may be used to treat acute hypoxic pulmonary hypertension.

Administration, Inhalation↗
PubMed1995

Borrelia burgdorferi DNA in biological samples from patients with sarcoidosis using the polymerase chain reaction technique.

Polymerase chain reaction (PCR) was used to detect the presence of Borrelia burgdoferi DNA in biological samples from patients with sarcoidosis. The target DNA sequence was of chromosomal origin. The amplified DNA sequence was analyzed by agarose gel electrophoresis, PAGE with silver staining, and the identity of amplified DNA was confirmed by restriction enzyme cleavage and DNA-DNA hybridization with a 32P-labelled probe. The assay was sensitive to fewer than two copies of B. burgdorferi genome, even in the presence of a 10(4)-fold excess of human eukaryotic DNA, and was also specific to different B. burgdorferi strains tested. Sera serologically positive to B. burgdorferi (n = 26), bronchoalveolar lavage fluid and supernatant of BALF (n = 26) and peripheral blood (n = 9) from sarcoidosis patients were tested. The positive rate was low (4/26, 2/26, and 0/9, respectively). It was considered that DNA from B. burgdorferi may be identified in a minority of patients with sarcoidosis, and it may play a pathogenetic role in such cases. More studies need to be done before advancing the hypothesis of an etiologic role of B. burgdorferi in sarcoidosis.

Base Sequence↗
PubMed1995

[Plasma endothelin 1 and its clinical evaluation in asthma].

Plasma endothelin 1 (ET1) was determined by radioimmunoassay in 28 cases of acute attack of asthma (attack group), 23 subjects of non-symptomatic asthma (remission group) and 20 normal volunteers (control group). The results showed that the plasma ET1 in attack group (13.4 +/- 5.2 fmol/ml) was much higher than that in both remission group (8.4 +/- 3.9 fmol/ml, P < 0.01) and control group (6.6 +/- 2.6 fmol/ml, P < 0.01). However, there was no significant difference between remission group and control group. The plasma ET1 level revealed notably negative correlation to PaO2 and FEV1% (r = -0.8257, r = -0.8157, P < 0.01). The results suggested that ET1 probably involved in pathophysiologic process of acute attack of bronchial asthma.

Adult↗