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Biomedical subjects

C Z Lu

Publications and source records attributed to C Z Lu.

36 records · Page 2Linked to original sources
PubMed1993

Interferon gamma- and interleukin-4-secreting cells in multiple sclerosis.

Interleukin 4 (IL-4)- and interferon gamma (IFN gamma)-secreting peripheral blood cells were enumerated by immunospot assay in 13 multiple sclerosis (MS) patients during exacerbations, in 24 patients with progressive multiple sclerosis (CPMS), and in 20 controls. Cells that spontaneously secreted IFN gamma were significantly higher in MS patients experiencing an attack (P < 0.001) than in controls or in CPMS (P < 0.04). IL-4-secreting cell numbers were elevated significantly and to a comparable extent in both MS groups compared to controls. Our finding of increased numbers of IFN gamma-secreting cells is in keeping with prior work showing increased IFN gamma levels in the circulation prior to and during MS attacks and increased release of IFN gamma to the supernatant in bulk cultured blood cells from MS patients. What role an increase in IL-4-secreting cells might play in MS is unclear, but it could relate to immune system regulation. Following in vitro exposure to MBP, IFN gamma-secreting cell number rose above levels observed in the absence of stimulation in controls and in both MS groups with the rise in acutely exacerbating MS patients being significantly greater than in controls. Our results provide further evidence for reactivity to MBP in MS, the significance of which in terms of pathogenesis remains clouded.

Acute Disease↗
PubMed1992

Myasthenia gravis: T and B cell reactivities to the beta-bungarotoxin binding protein presynaptic membrane receptor.

Antibodies against acetylcholine receptor (AChR) can be detected in most patients with myasthenia gravis (MG) and are considered to be involved in the immunopathogenesis of this disease. AChR are isolated from crude receptor preparations by binding to alpha-bungarotoxin (alpha-BuTx). Patients with MG have also antibodies against a second protein tentatively named presynaptic membrane receptor (PsmR), which has been isolated from crude receptor utilizing beta-bungarotoxin (beta-BuTx). PsmR could represent another antigen besides AChR relevant for the development of MG. We have now evaluated the T cell reactivity to PsmR in MG and controls by analysing the frequencies of cells which in response to PsmR in short-term cultures secreted interferon-gamma (IFN-gamma). The B cell response to PsmR was analysed in parallel by counting cells secreting anti-PsmR antibodies. Most patients with MG had PsmR reactive T cell in blood with a median number of about 1 per 44,000 mononuclear cells. Cells secreting anti-PsmR antibodies belonging to the IgG and IgA isotypes, less frequently of the IgM isotype were detected in most MG patients. A positive correlation was found between T cells reactive with PsmR and anti-PsmR IgG antibody secreting cells. PsmR reactive T and B cells were also detected in control patients, but at much lower numbers. Our results indicate that MG is accompanied by T as well as B cell responses to PsmR, in addition to the previously recognized responses to AChR. It remains to be shown whether these PsmR reactivities are of pathogenetic importance in MG.

Adult↗
PubMed1992

A preliminary observation on auto-cholinergic synapse dysfunction in patients with different types of epilepsy.

Serum anti-acetylcholine receptor antibodies (A AchR Ab) and anti-synaptic premembrane antibodies (A PrM Ab) were measured in 21 patients with absence epilepsy, 21 cases with benign childhood epilepsy with centro-temporal spikes (BCECTs) and 13 cases with atypical epilepsy. Respectively, in five (23.8%), eleven (51.2%) and eight (66.7%) of the above mentioned groups of patients both A AchR Ab and A PrM Ab were found.

Adolescent↗
PubMed1992

The formation and crystal structure of dihydronitidine and discussion of anticancer mechanism of nitidine cation.

The paper reports the formation and crystal structure of dihydronitidine, expounds the reasons and conditions of easily formed oxynitidine, and discusses anticancer mechanism of nitidine (cation). The crystallographic parameters of dihydronitidine are: space group P(2)1/n, a = 12.54(1), b = 9.148(5), c = 14.748(8) A, beta = 92.12(6)degrees, Z = 4. 4108 independent reflections were collected within the range of 3 degrees < or = 2 theta < or = 54 degrees, of which 2137 intensity data with I > or = 3 sigma (I) were used in the structural determination. The crystal structure has been refined by full matrix least-square method to a final R of 0.050.

Antineoplastic Agents, Phytogenic↗
PubMed1991

Anti-presynaptic membrane receptor antibodies in myasthenia gravis.

Myasthenia gravis (MG) is considered as an autoimmune disease of neuromuscular junction resulting from antibodies directed to acetylcholine receptors (AChR). We describe the use of beta-bungarotoxin (beta-BuTx) and alpha-bungarotoxin (alpha-BuTx) to capture their corresponding proteins from preparation of crude human muscle receptor. beta-BuTx binds to presynaptic membrane receptor (PsmR) of the whole receptor fraction, while alpha-BuTx binds to AchR. The captured proteins were used as antigen in ELISA to detect antibodies to PsmR and to AchR in sera from 82 Chinese patients with MG and in controls. In MG, antibodies to PsmR only were detected in 13%, to AchR only in 11% and both to PsmR and AchR in 54%. Only 3 of 50 patients with other neurological diseases and none of 50 healthy subjects had these antibodies. Specificity tests for antibodies showed that the detection systems which we used are specific and confident. No correlation was found between antibody levels and clinical status. The significance of the PsmR antibodies in the pathogenesis of MG is unknown. We suggest that myasthenia gravis is not only due to damage of the postsynaptic membrane, but of presynaptic structures as well.

Adult↗
PubMed1991

Immunological specificity and cross-reactivity of anti-acetylcholine receptor and anti-presynaptic membrane receptor antibodies in myasthenia gravis.

Antibodies against acetylcholine receptor (AChR), a protein that binds to alpha-bungarotoxin (alpha-BuTx), are characteristic for myasthenia gravis (MG) and are considered to be of importance in the pathogenesis of the disease. Antibodies against a beta-BuTx binding protein, presynaptic membrane receptor (PsmR), have also been reported in most MG patients. We have analysed the specificity and cross-reactivity of antibodies to bovine AChR and PsmR in sera from 11 patients with MG. More than 90% of antibodies to PsmR were adsorbed specifically by PsmR conjugated affinity chromatography. Similarly, more than 90% of anti-AChR antibodies were absorbed by AChR conjugated affinity chromatography. Specificities of antibodies from affinity chromatography were also confirmed by ELISA and agarose isoelectric focusing. However, the antibodies to PsmR and AChR from MG patients' sera showed about 45-55% cross-reactivity, and there was a high correlation between serum levels of both antibodies. The demonstration of anti-PsmR antibodies could be important in documenting presynaptic damage and understanding the pathogenetic process in MG.

Autoantibodies↗
PubMed1991

[Determination of pressure gradient across patent ductus arteriosus with simultaneous continuous wave Doppler and catheterization methods and non-invasive estimation of pulmonary artery pressure].

To evaluate the accuracy of Doppler technique for measuring the pressure gradient (delta P) across patent ductus arteriosus (PDA) with a simplified Bernoulli equation (delta P = 4 V2) and estimating the pulmonary artery pressure (PAP) by subtracting delta P from brachial arterial pressure (BAP) measured with cuff sphygmomanometry, Doppler echocardiography and catheterization (both left and right) were performed simultaneously in 20 patients with PDA. For the values of systolic peak delta P (SPPG), mean delta P (MPG) and end-diastolic delta P (EDPG) determined by both Doppler and catheter, the correlation was excellent (r = 0.99, 0.99, 0.99). Doppler determined SPPG also correlated well with catheter determined peak to peak delta P (P-PPG) (r = 0.97). Comparison between Doppler-derived and catheter measured systolic PAP (SPAP), mean PAP (MPAP) and diastolic PAP (DPAP) also showed high correlation (r = 0.95, 0.98, 0.97). This study demonstrates that Doppler echocardiography is valuable for measurement of delta P across PDA and non-invasive estimation of PAP in patients with PDA.

Adolescent↗
PubMed1990

Early diagnosis of tuberculous meningitis by detection of anti-BCG secreting cells in cerebrospinal fluid.

A nitrocellulose immunospot assay to enumerate cells secreting anti-BCG antibodies was evaluated in the diagnosis of tuberculous meningitis. Among 25 Chinese patients with this disease diagnosed on clinical and cerebrospinal fluid (CSF) criteria, 24 had anti-BCG IgG antibody secreting cells in CSF, at a median value of 56 per 10(4) CSF cells. Among 6 patients examined within one week, 5 had antibody secreting cells in CSF, and all 19 patients examined 2-8 weeks after onset had such cells in CSF. Blood examined from 5 patients contained anti-BCG IgG or IgM antibody secreting cells, but usually at much lower numbers than in corresponding CSF, indicating that the specific antibody response is largely confined to CSF. Anti-BCG antibodies measured in parallel by ELISA were slightly raised in CSF in only 1 of the 6 patients examined within a week, whereas a good correspondence was seen between numbers of antibody secreting cells and antibody concentrations from the second week onwards. Detection of anti-BCG IgG antibody secreting cells has higher sensitivity and specificity than ELISA measurement of anti-BCG IgG antibodies, and represents a new, useful method for the early diagnosis of tuberculous meningitis.

Adolescent↗
PubMed1990

[Estimation of systolic pulmonary artery pressure with continuous wave Doppler pressure gradient method: a simultaneous Doppler and catheter correlative study].

To estimate more precisely the systolic pulmonary artery pressure (PASP), continuous wave Doppler pressure gradient method and catheter measurement were performed simultaneously in 85 patients. There were 30 patients with tricuspid regurgitation (TR), 35 with ventricular septal defect (VSD), and 20 with patent ductus arterosus (PDA). For maximal transtricuspid pressure gradient (TRPG) determined by continuous wave Doppler and catheter determined PASP in TR group, the correlation coefficient (r) was as high as 0.99. For Doppler determined PASP (subtracting pressure gradient across PDA from systemic arterial pressure measured by cuff sphygmomanometer) and catheter determined PASP in PDA group, r was 0.95. Doppler determined PASP in VSD group (subtracting pressure gradient across VSD from systemic arterial pressure) also correlated well with catheter determined PASP (r = 0.97). This study demonstrates that continuous wave Doppler pressure gradient method can accurately estimate PASP in patients with TR, PDA, and VSD.

Adolescent↗
PubMed1989

Bone marrow cells in patients with multiple sclerosis.

Bone marrow cells from patients with multiple sclerosis (MS) were studied regarding proliferative capacity with and without mitogenic stimulation, immunohistochemical characterization of cellular phenotypes with monoclonal antibodies and morphology and compared to bone marrow cells from healthy individuals undergoing elective orthopaedic surgery. MS patients' bone marrow mononuclear cells (BM-MNC) showed higher spontaneous proliferation both in comparison with BM-MNC from controls and peripheral blood mononuclear cells (PBL) from MS patients. Phytohaemagglutinin (PHA) response was higher in MS BM-MNC than BM-MNC from controls. MS patients' BM-MNC proliferated more on interleukin-2 (IL-2) stimulation than their corresponding PBL. There was no significant difference in proliferative response of PBL between MS patients and controls. Higher levels of undifferentiated or activated cells, as measured by OKT10, were found in peripheral blood of patients with MS. Seven of 11 MS patients showed morphological signs of activation in their bone marrow. The results indicate a role for immune reactions in bone marrow in the pathogenesis of multiple sclerosis, a disease with symptoms and signs strictly confined to the central nervous system.

Adult↗
PubMed1989

Retrovirus in multiple sclerosis.

Presence of cytopathic effect and enzyme reverse transcriptase in cultures of peripheral blood mononuclear cells is described in 2 of 15 patients with multiple sclerosis and none of healthy controls. These findings might indicate: the presence of a new human retrovirus in these individuals, despite the low detection rate, and the shortcomings inherent in methodology used for detection of known human retroviruses in the study of new groups of diseases, such as those with possible autoimmune background.

Adult↗
PubMed1984

Association of HLA-DR4 with myasthenia gravis in the Chinese.

Since 1973 a number of studies have been conducted on the association of HLA with myasthenia gravis (MG). (Safwenberg et al. 1973, Fritze et al. 1973, Naeim et al. 1978, Bodmer & Bodmer 1978, Behan 1980). Most of these studies involved Caucasians. In this paper we report on a study carried out in Chinese patients with M.G.

Adult↗