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Biomedical subjects

C R Wang

Publications and source records attributed to C R Wang.

At least 73 records · Page 4Linked to original sources
PubMed1998

Expression of CTLA-4 molecule in peripheral blood T lymphocytes from patients with systemic lupus erythematosus.

CTLA-4 is a cell surface molecule expressed on activated T cells that is suggested to deliver a negative signal for T cell activation. Since CTLA-4 might be a negative regulator of autoimmune diseases, we investigated its expression on T cells from 20 patients with systemic lupus erythematosus (SLE) by flow cytometric analysis and RT-PCR. We found that although CTLA-4 mRNA was readily detected in all patients and controls, only a very minor subset of T cells expressed detectable surface CTLA-4 molecules in both groups. But patients with SLE had significantly increased percentages of CTLA-4-positive T cells compared with normal controls, implying at least that there was no apparent defective expression of CTLA-4 molecule in human lupus. The kinetics of CTLA-4 expression on T cells stimulated in vitro with PMA plus ionomycin were similar in normal controls and patients with SLE. The expression of CTLA-4 molecules after stimulation increased gradually and peaked at 72 hr. However, the induction of CTLA-4 expression on patients' T cells appeared to be weaker than that of normal individuals. Whether this reflects impaired downregulation by CTLA-4 molecules in SLE patients needs to be clarified further.

Abatacept↗
PubMed1998

Bone healing of tibial lengthening is enhanced by hyperbaric oxygen therapy: a study of bone mineral density and torsional strength on rabbits.

We investigated the effect of intermittent hyperbaric oxygen (HBO) therapy on the bone healing of tibial lengthening in rabbits. Twelve male rabbits were divided into two groups of six animals each. The first group went through 2.5 atmospheres absolute of hyperbaric oxygenation for 2 hours daily, and the second group did not go through hyperbaric oxygenation. Each animal's right tibia was lengthened 5 mm using an uniplanar lengthening device. Bone mineral density (BMD) study was performed for all of the animals at 1 day before operation and at 3, 4, 5, and 6 weeks after operation. All of the animals were killed at 6 weeks postoperatively for biomechanical testing. Using the preoperative BMD as an internal control, we found that the BMD of the HBO group was increased significantly compared with the non HBO group. The mean %BMD at 3, 4, 5, and 6 weeks were 69.5%, 80.1%, 87.8%, and 96.9%, respectively, in HBO group, whereas the mean %BMD were 51.6%, 67.7%, 70.5%, and 79.2%, respectively, in non-HBO group (two tailed t test, p < 0.01, p < 0.01, p < 0.01, and p < 0.01 at 3, 4, 5, and 6 weeks, respectively). Using the contralateral nonoperated tibia as an internal control, we found that torsional strength of lengthened tibia of the HBO group was increased significantly compared with the non-HBO group. The mean percent of maximal torque was 88.6% in HBO group at 6 weeks, whereas the mean percent of maximal torque was 76.0% in non-HBO group (two-tailed t test, p < 0.01). The results of this study suggest that the bone healing of tibial lengthening is enhanced by intermittent hyperbaric oxygen therapy.

Absorptiometry, Photon↗
PubMed1998

Hemoptysis in children.

BACKGROUND: Hemoptysis is rare in children, yet is one of the most frightening manifestations of cardiopulmonary disease. A wide spectrum of diseases has been reported to cause hemoptysis in children, but the search for a specific cause can be tedious and unrewarding. Early diagnosis and interventions of hemoptysis are extremely important for the successful management of this potentially lethal process in children. METHODS: From July 1994 to June 1996, 15 pediatric patients ranging from 1 month to 15 years of age were admitted to the Pulmonology division for the investigation of hemoptysis. We retrospectively reviewed the clinical records and diagnostic evaluations of these patients. RESULTS: Six (40%) of the patients investigated were infectious in origin, only one patient had tuberculous infection. Three patients had a traumatic cause and 2 patients had foreign bodies in the airway. Two cases had no obvious contributing cause of hemoptysis despite extensive investigations. One patient had hematemesis because bleeding from esophageal ulcerations was misinterpreted as hemoptysis. One patient had varicosed tracheal and bronchial collaterals causing massive hemoptysis due to portal vein obstruction and hypertension. CONCLUSION: Pulmonary infection was the leading cause of hemoptysis in the 15 children we studied, but Mycobacterium tuberculosis is an uncommon causative agent. Bronchoscopy is an extremely useful tool for the diagnosis and localization of hemoptysis. Hematemesis may be misinterpreted as hemoptysis, particularly when an accurate history is not possible in children, therefore, bleeding from the upper aerodigestive tract should be studied meticulously and excluded adequately using endoscopy.

Adolescent↗
PubMed1998

Liquid ventilation for treatment of meconium aspiration syndrome in a piglet model.

We tested the hypothesis that liquid ventilation (LV) with perfluorocarbon (PFC) can remove aspirated meconium and improve lung function in experimental meconium aspiration syndrome (MAS). PFC (FC-77) was used as the medium in LV. Sixteen piglets were divided into control and LV groups (8 animals/group). All animals received slurry meconium (20% in normal saline) via endotracheal instillation at baseline. Thirty minutes later, the LV group received 15 cycles of LV. Pulmonary mechanics, arterial blood gases, and hemodynamic values were recorded at baseline, and 30, 60, 120, 180, and 240 minutes after meconium instillation. Chest radiographs and lung sections were taken and scored at the end of the study. The percentage of meconium cleared by LV was calculated as the ratio of the dry weight of washings to that of meconium instilled, multiplied by 100. The procedure was tolerated well by the animals. LV cleared 25% +/- 7% of the instilled meconium. Tidal volume (9.5 +/- 2.0 vs 7.1 +/- 0.8 mL/kg, p = 0.012), respiratory system compliance (2.32 +/- 0.60 vs 1.60 +/- 0.24 mL/cmH2O, p = 0.01), PaO2 (65 +/- 7 torr vs 55 +/- 6 torr, p = 0.0067), and arterial to alveolar oxygen ratio (0.14 +/- 0.01 vs 0.12 +/- 0.01, p = 0.0077) were improved in the LV group at 60 minutes after meconium instillation compared with those of the control group. The scores of exudative debris (1.7 +/- 0.3 vs 2.1 +/- 0.2) and visible meconium (1.4 +/- 0.5 vs 2.1 +/- 0.5) were significantly lower in the LV group. In conclusion, short-term L.V with FC-77 can partially remove aspirated meconium from the lungs and improve pulmonary function transiently.

Animals↗
PubMed1997

Identification, expression, and crystallization of the protease-resistant conserved domain of synapsin I.

A 35-37-kDa protease-resistant domain of synapsin Ia/ Ib, apparently produced by low levels of endogenous proteases in vapor diffusion droplets, slowly formed crystals diffracting X-rays to approximately 10 A resolution. The fragment mainly consisted of the highly conserved C domain common to the synapsin I/II family plus short N- and C-terminal flanking segments. Two constructs (SynA and SynB) of synthetic gene fragments coding for the C domain of synapsin with or without C-terminal flanking sequence were expressed in Escherichia coli as fusion proteins attached to the soluble protein glutathione-S-transferase. The fusion proteins were purified by affinity chromatography. Subsequent in situ cleavage with TEV protease resulted in the release of highly pure synapsin fragments, which were further purified by ion exchange chromatography. SynA and SynB formed crystals within three days, which diffracted to better than 3 A using a conventional X-ray source and to about 2 A using a synchrotron X-ray source. SynA crystals have the symmetry of the trigonal space groups P3(1)21 or P3(2)21 and the unit cell dimensions a = b = 77.4 A, c = 188.5 A, alpha = beta = 90 degrees, gamma = 120 degrees. SynB crystals have the symmetry of the orthorhombic space group C222(1) with the unit cell dimension a = 104.6 A, b = 113.3 A, and c = 273.8 A.

Crystallography, X-Ray↗
PubMed1997

Measurement of synovial tumor necrosis factor-alpha in diagnosing emergency patients with bacterial arthritis.

Because of the high morbidity and mortality in patients with bacterial arthritis, rapidly and correctly diagnosing this critical condition is a challenge to emergency clinicians. Synovial fluid samples were obtained from 75 patients with arthritis disorders who presented to an emergency service, and levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) were measured. Twenty patients with culture-proven bacterial arthritis had higher levels of synovial TNF-alpha than patients with osteoarthritis or with inflammatory arthritis, including gouty arthritis, rheumatoid arthritis, reactive arthritis, and lupus arthritis. There was a good sensitivity for synovial TNF-alpha level in diagnosing patients with bacterial arthritis. Nearly 100% of patients with bacterial arthritis had elevated synovial TNF-alpha levels. However, synovial IL-1 beta and IL-6 levels failed to discriminate bacterial arthritis from other inflammatory arthritis. Measurement of synovial TNF-alpha level may be useful as a diagnostic aid in emergency patients with bacterial arthritis disorders.

Adult↗
PubMed1997

Impaired NK1+ T cell development and early IL-4 production in CD1-deficient mice.

The MHC class lb molecule, CD1, has been conserved throughout mammalian evolution. To assess the function of CD1 in lymphocyte development, we generated mice with targeted disruption of the CD1.1 and CD1.2 genes. CD1-deficient mice have normal numbers of CD4+ and CD8+ T cells but marked reduction in NK1.1-bearing T cells, particularly those with a canonical gene rearrangement of V alpha14-J alpha281. CD1-deficient mice are unable to generate a rapid IL-4 response following systemic T cell activation but can generate effective antigen-specific Th2 responses. Thus, CD1 is required for the development of a specialized subset of T lymphocytes with a monomorphic antigen receptor. The rapid effector cytokine secretion of these T cells suggests that CD1 educates adaptive immune cells to subserve functions of innate immunity.

Animals↗
PubMed1997

H2-M3, a full-service class Ib histocompatibility antigen.

H2-M3 is an MHC class Ib molecule of the mouse with a unique preference for N-formylated peptides, which may come from the N-termini of endogenous, mitochondrial proteins or foreign, bacterial proteins. The crystal structure of M3 revealed a hydrophobic peptide-binding groove with an occluded A pocket and the peptide shifted one residue relative to class Ia structures. The formyl group is held by a novel hydrogen bonding network, involving His9 on the bottom of the groove, and the side chain of the P1 methionine is lodged in the B pocket. M3 is a full-service histocompatibility (H) antigen, i.e. self-M3 can present endogenous peptides as minor H antigens and foreign, bacterial antigens in a defensive immune response to infection; and foreign M3 complexed with endogenous self-peptides.

Amino Acid Sequence↗
PubMed1997

CD69 to CD3 ratio of peripheral blood mononuclear cells as a marker to monitor systemic lupus erythematosus disease activity.

CD69 is an early T cell activation marker. In order to investigate whether the disease activity of systemic lupus erythematosus (SLE) is correlated with T cell hyperactivity as well as B cell hyperactivity, we measured the CD69 to CD3 ratio (CD69/CD3) of peripheral blood mononuclear cells (PBMCs) from 42 SLE patients and 18 healthy controls. To assess B cell activation, we measured the levels of anti-dsDNA, complement C3 and C4. Disease activity was assessed with the SLE disease activity index (SLEDAI) score. The mean value (+/- standard deviation) of CD69/CD3 for SLE patients (3.34 +/- 0.486) and healthy controls (0.92 +/- 0.015) were significantly different (P < 0.05). CD69/CD3, anti-dsDNA, C3 and C4 were all significantly correlated with SLEDAI (r = 0.50, 0.51, -0.68, -0.31, respectively, P < 0.05). CD69/CD3 could explain 25.4% of the variance in SLEDAI, and 6.7% of the variance that was independent of anti-dsDNA, C3 and C4. In patients with SLEDAI scores which were discordant with anti-dsDNA, C3 and C4 values, CD69/ CD3 still showed high correlation with SLEDAI. We conclude that CD69/CD3, which detects T cell activation is correlated with SLEDAI scores. Thus, T cell activation contributes part of the disease activity independent of B cell activity. This marker can complement in the estimation of disease activity when levels of anti-dsDNA, C3 and C4 fail to show good correlation.

Adult↗
PubMed1997

MRI-guided stereotatic aspiration for the treatment of deep-seated tentorial empyema: a case report.

Tentorial empyema is a rare intracranial infection. In the past, most authors treated the subdural empyema by craniotomy, craniectomy or burr hole drainage. In the case presented, magnetic resonance imaging (MRI)-guided stereotatic aspiration was used to treat deep-seated extensive tentorial empyema successfully, via a simple burr hole to avoid any brain resection and retraction. This operation method is relative simple and effective for treating deep-seated intracranial empyema, significantly reduces the risk of injury to the lateral temporal lobe cortex or transection of optic radiations. On the other hand, it must be emphasized that contrast-enhanced MRI scan may offer a more sensitive and better diagnostic procedure than contrast enhanced computed tomography (CT) scan.

Adult↗
PubMed1996

The study of circulating CD5 positive B lymphocytes in Chinese patients with rheumatoid arthritis.

Circulating CD5+ B lymphocytes were studied in 39 Chinese patients with rheumatoid arthritis (RA). Blood cells were stained with anti-CD5 and anti-CD19 monoclonal antibodies and were analyzed by flow cytometry. The results showed that there was no elevation of CD5+ B cells in RA patients when compared with 41 healthy control subjects. The circulating levels of CD5+ B cell correlated neither with serum titers of rheumatoid factor (RF) nor with disease activities in these patients. The CD5+ B cell levels remained relatively constant after a serial follow-up for 12 months. The similar pattern of epitope density of CD5 antigens also existed in the same patients. Although most studies in Caucasians revealed increased levels of CD5+ B cells in RA patients, measurements of this marker were not useful for the evaluation of disease activities in Chinese patients. Levels of CD5+ B cells may reflect more individual genetic background and may play a minor role in the flare-up of activities in Chinese patients with RA.

Adult↗
PubMed1996

Concomitant fracture of the coracoid and acromion after direct shoulder trauma.

Fractures of the acromial process or coracoid process of the scapula are rare. We present a combined fracture of the coracoid and acromion after direct trauma to the shoulder. An anteroposterior radiography with the central x-ray beam angled 25 degrees cephalad or an axillary lateral radiograph may be needed to detect these fractures.

Acromion↗
PubMed1996

Elevated levels of anticardiolipin antibodies and epilepsy in lupus patients.

To examine the association between anticardiolipin (aCL) antibodies and epilepsy, we investigated the serum titers of aCL antibodies in a total 252 systemic lupus erythematosus (SLE) patients recruited in a prospective study. Twenty-one cases with epilepsy which were not attributable to any causes other than SLE were identified after being followed-up for five years. The clinical manifestations were recorded and blood samples were tested for the presence of aCL antibodies (IgG, IgM and IgA isotypes). Among 21 patients with epilepsy, 12 (57.1%), 2 (9.5%) and 2 (9.5%), respectively, had elevated baseline serum levels of IgG, IgM and IgA aCL antibodies. There was a dose-response relationship between risk of seizure and the baseline serum level of aCL antibodies (P < 0.01). The odds ratio of developing seizure were 3.7 for those who had a high level of aCL antibodies compared with those without a detectable level of aCL antibodies as the referent. Our results indicate that epilepsy as a primary neuropsychiatric event among lupus patients is associated with a high titer of aCL antibodies.

Adolescent↗
PubMed1995

Nonclassical binding of formylated peptide in crystal structure of the MHC class Ib molecule H2-M3.

H2-M3 is a class Ib MHC molecule of the mouse with a 10(4)-fold preference for binding N-formylated peptides. To elucidate the basis of this unusual specificity, we expressed and crystallized a soluble form of M3 with a formylated nonamer peptide, fMYFINILTL, and determined the structure by X-ray crystallography. M3, refined at 2.1 A resolution, resembles class la MHC molecules in its overall structure, but differs in the peptide-binding groove. The A pocket, which usually accommodates the free N-terminus of a bound peptide, is closed, and the peptide is shifted one residue, such that the P1 side chain is lodged in the B pocket. The formyl group is coordinated by His-9 and a bound water on the floor of the groove.

Amino Acid Sequence↗