[The effect of glycoside Tripterygium wilfordii Hook F on the immune regulatory function of T lymphocyte]

Previously, we treated successfully patients with systemic lupus erythromatosus (SLE) with glycoside Tripterygium Wilfordii Hook F, a Chinese medicinal herb. To evaluate the pharmacological mechanism of this herb, we studied its effects on the activation and proliferation facets of human T lymphocyte in vitro. The results revealed that this drug can markedly suppress the activation and proliferation facets of T lymphocytes.

Isolation and fractionation of retroviral tRNAs

Previous studies concerning the analysis of retroviral tRNA populations involved intracellular metabolic labeling of RNA, followed by the isolation of viral RNA and lengthy sucrose gradient centrifugation for the separation of tRNAs found in various viral compartments. A more rapid, convenient, and safer method for achieving similar aims is described. Isolated total viral RNA is end-labeled in vitro, and tRNA subgroups are fractionated using commercial Nucleobond AX-20 mini columns. 2-D PAGE analysis of mouse mammary tumor virus tRNA fractionated in this way yields gel patterns similar to those obtained with previously described methods.

Variable tRNA content in HIV-1IIIB

Low molecular weight RNA in HIV-1 is found in three size classes resembling 7S RNA, 5S RNA, and tRNA. The 2-dimensional polyacrylamide gel electrophoresis (2D PAGE) patterns of tRNA found in HIV-1 have been determined in virus produced in five different cell types: H9, UHC1 (a U937-derived clone), UHC8 (an RT(-) derivative of U937), HeLa, and COS. The presence of the putative primer tRNA for reverse transcriptase, tRNA(Lys,3), has also been determined either by hybridization with a tRNA(Lys,3)-specific DNA probe or by a comparison of the electrophoretic mobility of viral tRNA species with purified human tRNA(Lys,3). Our results indicate the following: 1) The number of tRNA species found in infectious HIV-1IIIB produced in different cell types varies, according to cell type, from greater than 20 to 4, indicating that only 4 or less tRNA species are required for the viral infectious life cycle. 2) There are 1-3 tRNA species tightly associated to the viral genomic RNA, depending upon the cell type producing the virus. 3) The putative primer tRNA, tRNA(Lys,3), is detected with the tRNA(Lys,3)-specific hybridization probe in the tRNA of HIV-1 produced in H9 cells, and the tightly associated tRNA species in this virus has the same electrophoretic mobility in 1-D PAGE as purified tRNA(Lys,3). On the other hand, we cannot detect tRNA(Lys,3) in the tRNA of HIV-1 produced in HeLa cells, and the tightly associated tRNA found in this virus does not migrate with the same electrophoretic mobility as tRNA(Lys,3).

[Detection of anti-dsDNA-F(AB')2 antibody and evaluation of its clinical significance]

Purified anti-dsDNA antibody was obtained from the serum of patients with systemic lupus erythematosus by affinity-column chromatography. Anti-dsDNA-F(ab')2 fragment (idiotype) was prepared from digested anti-dsDNA antibody with pepsin. We have developed a sensitive and specific method for detection anti-dsDNA-F(ab')2 antibody. Our result revealed that low titer of anti-dsDNA was observed in patients with active stage of systemic lupus erythematosus.

Transient elevation of the intracranial pressure increases the infarct size and perifocal edema after subsequent middle cerebral artery occlusion in the rat

The objective of this study was to mimic in a simple experiment the two major brain insults sustained by the patient with a subarachnoid hemorrhage, that is, the ictus and the subsequent delayed reduction of focal cerebral blood flow caused by vasospasm without the interference of subarachnoid blood, to test the hypothesis that ictal events not related to the presence of blood in the subarachnoid space per se may be important for the development of ischemic deficits and cerebral infarction when vasospasm develops. Groups of rats were subjected to a sudden transient elevation of the intracranial pressure to a level causing a brief period of complete global ischemia by infusion of mock cerebrospinal fluid into the cisterna magna (this manipulation was designed to allow survival of the animal and recovery of consciousness). Two and one-half hours later, a focal ischemic insult was induced by occlusion of the middle cerebral artery. Rats subjected to middle cerebral artery occlusion alone and sham operation served as controls. The infarct size was used as the end point and was calculated on brain slices stained with 2,3,5-triphenyltetrazolium chloride. The study demonstrates that a brief sudden elevation in intracranial pressure, in itself consistent with survival and recovery, increased the vulnerability of the brain to a subsequent focal ischemic insult. Thus the combination of insults resulted in significantly (P less than 0.05) larger infarcts than did middle cerebral artery occlusion alone. Further, this combination of insults resulted in a disproportionate enlargement of the affected hemisphere, which could not be explained by the increased infarct size alone.

[Study on anti-histone fraction antibodies in patients with rheumatic diseases]

By using Western blot method, we studied the antihistone fraction antibodies in sera of patients with rheumatic diseases. After analysed with SDS-PAGE, the histone could be separated into H1, H3, H2B, H2A and H4 fractions. The positive rate of anti-histone fraction antibodies was highest (82.1%) in systemic lupus erythematosus (SLE) patients, especially in active stage. In 28 SLE patients, the positive rates of anti-H2B, -H1, -H3, -H2A and -H4 were 78.6%, 60.7%, 50.0%, 35.7% and 7.1% respectively. The results revealed that the determination of anti-histone fraction antibodies was beneficial to the diagnosis of SLE.

High-level expression of staphylococcal nuclease R gene in Escherichia coli

Staphylococcal nuclease R, an analogue of nuclease A, was overproduced under the transcriptional control of the bacteriophage lambda PRPL promoters regulated by temperature sensitive repressors. The expression level reached 200-300 mg l-1 and showed little host dependence in different strains. The investigations of the recombinant nuclease R have revealed that the amino terminal formyl methionine residue of the nuclease is precisely processed, the protein consists of 155 amino acid residues. The experiment shows that the pBV221-DH5 alpha is a quite suitable vector-host system for high-level expression and precise processing of heterologous genes in Escherichia coli. The comparative studies between the codons used in the staphylococcal nuclease R gene and the optimal codon usage in E. coli indicate that high level expression of heterologous genes in E. coli may not always require a high degree of codon usage bias.

[The changes in renin-angiotensin-aldosterone system in acute myocardial infarction and the effects of converting enzyme inhibitor-captopril]

A serial measurements of plasma renin activity (PRA), serum angiotensin converting enzyme activity (ACE), concentrations of plasma angiotensin II (AII) and plasma aldosterone (Ald) in 38 consecutive patients with acute myocardial infarction (AMI) or suspected AMI showed that PRA, AII and Ald levels increased in patients with AMI, especially within first week after onset, and were significantly higher in those cases with severe complications. ACE kept in normal range in all subjects. After small dose captopril therapy, ACE and Ald decreased significantly, PRA and AII increased in 6 patients with AMI. Small dose captopril could cause remarkable blood pressure reduction, but no effect on heart rate. The results suggested that renin-angiotensin-aldosterone system was activated during AMI, especially in cases with severe complications. Captopril could inhibit this system partially.

The 1958 and 1987 ARA revised criteria for rheumatoid arthritis in Chinese patients. A comparative study

The American Rheumatism Association (ARA) 1958 and 1987 criteria for the classification of rheumatoid arthritis (RA) were applied to 111 consecutive RA patients and 54 patients with non-RA connective tissue diseases from three hospitals of tertiary level in Beijing. Comparison of the two criteria showed that the specificity was the same, being 88% for both, whereas the sensitivity varied from 94% of the 1958 criteria to 91% of the 1987 criteria. Factors affecting the sensitivity were morning stiffness for more than one hour and increase of number of swollen joints from one to three in the 1987 revised criteria.

[Studies on the T4+2H4+ cell of peripheral blood lymphocyte in systemic lupus erythematosus]

The cell surface phenotype of peripheral blood lymphocytes in patients with systemic lupus erythematosus (SLE) was studied with the anti-T4+, T8+ and T4+2H4+ monoclonal antibodies by flow cytometry. 13 patients with active SLE had a markedly low percentage of T4+2H4+ cells but had normal percentage of T8+ cells. Our results reveal that the influence of T cell to B cell is not only because of the quantity of T cells, also because of the function of T cells. The abnormality of T4+2H4+ cells may be important in the pathogenesis of SLE.

Guanine nucleotide-binding regulatory proteins in retinal pigment epithelial cells

The expression of GTP-binding regulatory proteins (G proteins) in retinal pigment epithelial (RPE) cells was analyzed by RNA blot hybridization and cDNA amplification. Both adult and fetal human RPE cells contain mRNA for multiple G protein alpha subunits (G alpha) including Gs alpha, Gi-1 alpha, Gi-2 alpha, Gi-3 alpha, and Gz alpha (or Gx alpha), where Gs and Gi are proteins that stimulate or inhibit adenylyl cyclase, respectively, and Gz is a protein that may mediate pertussis toxin-insensitive events. Other G alpha-related mRNA transcripts were detected in fetal RPE cells by low-stringency hybridization to Gi-2 alpha and Gs alpha protein-coding cDNA probes. The diversity of G proteins in RPE cells was further studied by cDNA amplification with reverse transcriptase and the polymerase chain reaction. This approach revealed that, besides the above mentioned members of the G alpha gene family, at least two other G alpha subunits are expressed in RPE cells. Human retinal cDNA clones that encode one of the additional G alpha subunits were isolated and characterized. The results indicate that this G alpha subunit belongs to a separate subfamily of G proteins that may be insensitive to inhibition by pertussis toxin.

[Antineuronal antibodies and neuropsychiatric systemic lupus erythematosus]

Determination of antineuronal antibodies was carried out by a solid phase radioimmunoassay, in which the neuronal cells SK-N-SH were cultured as the target antigens, the positive rate in sera and CSF of neuropsychiatric SLE patients being 85% and 77.8% respectively, all with quite high level of antibodies. Although 66.7% sera of SLE patients without CNS involvement were also positive for the antibodies, yet the antibody levels of them were distinctly lower, and only 3 of them showed weak positive reactions in their CSF. It was shown that 90% of neuropsychiatric SLE patients with diffuse CNS manifestations had increased antineuronal antibodies, compared with only 20% in cases with local CNS involvements. The antibody levels both in sera and CSF decreased remarkably following the patients' recovery from the neuropsychiatric attack. It is concluded that the antineuronal antibodies might play a role in the pathogenesis of neuropsychiatric lupus and the determination of them in CSF might be useful in the diagnosis and differential diagnosis of neuropsychiatric lupus.

[Development and preliminary characterization of monoclonal antibodies to 987P adhesin antigen of E. coli]

A panel of 11 monoclonal antibodies (MAbs) to 987P adhesin antigen of E. coli were developed and partially characterized. They only reacted with E. coli strains bearing 987P adhesin but neither with other E. coli (K88+, K99+ and F41+) strains nor other species in family of Enterobacteriaceae in IF or ELISA. The amount of 987P+ bacteria which could be detected by the HRPO-conjugated MAb EPN3 was as small as 2 X 10(3) cells/ml, and the detected rate of fecal or intestinal samples from piglets with artificially induced diarrhoea by IF and/or ELISA was 4/4 and 6/6, respectively. The adhesion of 987P+ E. coli to porcine intestinal epithelial cells could be inhibited by seven of these MAbs in vitro. The binding pattern of MAb EPN2 with 987P fimbriae as shown in immunogold stain under electron microscope was periodic and discrete distribution along the length of each of the fimbriae. ELISA and IF blocking test suggested that there were at least 3 kinds of determinants on 987P adhesion. These MAbs were not only useful in identification of 987P fimbriae of enterotoxigenic E. coli, but also in the studies of its molecular structure and biological function.

The effect of [Met]enkephalin on the periaqueductal gray neurons of the rat: an in vitro study

Intracellular and extracellular recording techniques and in vitro preparation were used to examine the effect of [Met]enkephalin on the rat periaqueductal neurons. In the 20 cells that were recorded intracellularly, [Met]enkephalin caused an increase in the resting membrane conductance, hyperpolarization of the cell membrane, an increase in the firing threshold and a decrease in the spontaneous firing rate. This effect of [Met]enkephalin could be blocked by naloxone. The effect of [Met]enkephalin on 99 neurons was also examined using extracellular recording. In 59% of cells, pressure application of [Met]enkephalin caused a dose-dependent inhibition that could be blocked by naloxone; 15% of the cells were excited and the remaining neurons (26%) did not respond. Nineteen per cent of responsive cells were located in the dorsolateral subdivision; 41% in the ventrolateral and 13% in the dorsal regions. In 10 cells, perfusion with physiological saline solution/Mg did not alter the inhibitory effect of [Met]enkephalin. However, perfusion with physiological saline solution/Mg abolished the excitatory response to [Met]enkephalin in four cells. It is concluded that: (1) the major effect of [Met]enkephalin on periaqueductal gray cells is inhibition that occurs through a direct postsynaptic process. This inhibition is probably due to an increase in permeability to potassium; (2) a small population of periaqueductal gray cells are excited by [Met]enkephalin, probably through a presynaptic process.

A new colorimetric assay for purine nucleoside phosphorylase

A new colorimetric procedure for the determination of purine nucleoside phosphorylase (PNP, E.C. 2.4.2.1) activity is described. In this procedure, the hydrogen peroxide formed in the PNP-xanthine oxidase reaction is used to oxidize the chromogenic reagents--3,5-dichloro-2-hydroxybenzenesulfonic acid/4-aminophenazone using the enzyme peroxidase. The rate of enzyme reaction is followed at 520 nm. This procedure correlated well with the UV method (290 nm), with a correlation coefficient of 0.98 (P less than 0.005). Within-run and between-run precision (CV) were less than 2.8% and 3.7%, respectively. Here we also describe an optimized NAD-dependent method (340 nm) for PNP determination. The colorimetric method is superior to both the 340 nm and the UV methods in terms of both sensitivity and precision. The mean erythrocyte PNP activity for 17 healthy subjects was 11.88 U/mL packed cells for the NAD-dependent method and 13.22 U/mL packed cells for the colorimetric method.

Purine nucleoside phosphorylase in erythrocytes: determination of optimum reaction conditions

Reaction conditions for determining the activity of purine nucleoside phosphorylase (PNP; E.C. 2.4.2.1) were investigated. We examined the kinetic parameters for the enzymatic reaction with respect to the substrates inosine and phosphate. We confirmed the pH optimum, established the optimal concentration of xanthine oxidase and that of calcium and magnesium. The Km values for inosine and phosphate were found to be 60 uM and 667 uM, respectively. Optimum assay conditions for PNP activity were established. This optimized method has been compared with other procedures and found to be more sensitive and to yield significantly higher activities. The experimental variation of a manual procedure using these optimum reaction conditions was less than 4.5%. The mean erythrocyte PNP activity of 28 healthy subjects was estimated to be 9.71 U/mL packed cells at 25 degrees C and 18.60 U/mL packed cells at 37 degrees C.

[Inhibitory effect of pingyangmycin on human liver cancer and stomach cancer xenografts in nude mice]

Established human cancer cell lines derived from liver cancer (BEL-7402), nasopharyngeal cancer (CNE-2) and stomach cancer (MGC-803) were used in this study. These human cancer cells have been serially transplanted in nude mice. As determined by clonogenic assay, pingyangmycin (bleomycin A5) was highly cytotoxic to these three cell lines, of which the liver cancer cell line was more sensitive than the other two. At a tolerated dose level, pingyangmycin exhibited a remarkable growth inhibition on the growth of the liver cancer and stomach cancer xenografts, the inhibition rates being 70% and 85%, respectively. No pathologic changes were found in the organs of treated animals.