Transcription of a human neurotropic virus promoter in glial cells: effect of YB-1 on expression of the JC virus late gene

We have isolated a partial recombinant cDNA clone from a HeLa expression library which encodes a protein capable of binding to the central region of the human neurotropic JC virus (JCV) enhancer/promoter, termed the B region. Sequence analysis revealed a complete homology of the partial cDNA clone to the N-terminal region, of a previously described DNA-binding protein, termed YB-1. Band shift analyses have indicated that the bacterially produced YB-1 interacts specifically with the double-stranded B oligonucleotide as well as the corresponding single-stranded DNA fragment representing the early promoter sequence. Further analysis indicated that the YB-1 protein binds specifically to the C/T-rich sequence of the B domain, which is located in close proximity to the TATA box within the virus enhancer/promoter. Results from cotransfection experiments demonstrated that the full-length (YB-1) but not the partial cDNA enhances expression of the JCV late (JCVL) promoter in glial cells. Cointroduction into glial cells of a recombinant expressing the YB-1 and JCVL deletion mutants indicated that removal of the C/T-rich sequence of the B domain reduces the level of activation of the virus promoter by YB-1. Further cotransfection experiments revealed that the virus transactivating protein T antigen appears to diminish the ability of YB-1 to activate JCVL gene expression. RNA studies indicated that YB-1 is expressed in several cell types and tissues. Examination of YB-1 RNA from mouse brain at various stages of development revealed high levels of YB-1 RNA at early stages of development and lower levels at all subsequent developmental stages.

[Changes in serum lipoprotein cholesterol in rabbit model of calcium bilirubinate cholangiolithiasis]

The lithogenic process of cholangiolithasis is still not understood clearly. In this study, several serum lipoprotein cholesterol, the bile BA level, etc. in the rabbit model of calcium bilirubinate cholangiolithiasis was examined. The main results included: (1) The concentrations of HDL-ch and HDL2-ch in the serum decreased in all the experimental groups (P < 0.01; P < 0.05), except HDL-ch in the BO 1W group (P > 0.05) compared with the control group. The concentrations of HDL2-ch in the BOI 1W and the BOI 6W groups were lower than those in the BO 1W and the BO 6W groups respectively (P < 0.05); the both concentrations of Fch and HDL3-ch in the BOI and the BO groups were much higher than those in the control group (P < 0.01). (2) The bile T-BA level was lower in the both BOI groups than that in the control group (P < 0.05). It began to decrease in the BO group during the first week, but it was not significant in statistical difference (P > 0.05). During the 6th week the level of the bile acid (BA) was much lower than that in the control group (P < 0.05). According to the above results, it may be concluded that in the formation of calcium bilirubinate gallstones, caused by the biliary obstruction and infection, there is a disorder in the lipoprotein metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of paraquat toxicity in suspensions of alveolar type II cells by paraquat-specific antibodies

1. The herbicide, paraquat, is accumulated by the energy-dependent polyamine uptake pathway of alveolar type II cells. There it undergoes redox cycling that results in an amplified production of toxic reactive oxygen species and depletion of NADPH and other reducing equivalents. These processes account for the lung being the major target organ for paraquat toxicity. 2. We postulated that paraquat-specific antibodies would inhibit the uptake of the herbicide by type II cells and prevent its toxicity. Accordingly, we examined the effects of paraquat-specific monoclonal antibodies and Fab fragments on the uptake, efflux and cytotoxicity of 50 microM paraquat in suspensions of alveolar type II cells isolated from the rat. 3. The uptake of paraquat was linear over 40 min. Over this time, the uptake rate was inhibited significantly (% inhibition, 73-89) by IgG (25 or 50 microM) or Fab fragments (50 or 100 microM). 4. The apparent efflux rate of paraquat, studied over 16 h, was increased significantly from 0.12 h-1 for the control cells in medium to 0.17 h-1 by paraquat-specific Fab fragments but was unaffected by the specific IgG. 5. Cytotoxicity was determined by measuring the release of 51Cr from the cells. The cytotoxicity of 50 microM paraquat was decreased significantly (percent decrease, 56-80%) in the presence of specific antibodies. 6. These studies in vitro suggest some potential for immunotherapy in selected cases of paraquat poisoning.

Physical map of a 2 Mb chromosome of the intestinal protozoan parasite Giardia duodenalis

The protozoan parasite, Giardia duodenalis, is regarded as the most primitive eukaryote. The two apparently identical nuclei presumably carry the same chromosomes but the number of different chromosomes in the organism is unknown. A genome map of G. duodenalis is required to resolve this issue and mapping studies were initiated using chromosome 5. This chromosome was estimated to be approximately 2 Mb when Giardia chromosomes were separated by contour-clamped homogeneous electric field gel electrophoresis. A plasmid library of chromosome 5-specific DNA sequences was constructed from gel-extracted chromosome 5 and selected probes were used as markers to identify NotI DNA segments derived from chromosome 5. Fifty-nine unique copy markers were used to identify thirteen NotI segments which ranged in size from 47 kb to 400 kb. The sum of the NotI segments was 1.78 Mb which indicated that most, if not all, of the chromosome was accounted for and that chromosome band 5 of the cloned line WB-1B, used in this study comprised only one chromosome type. The NotI segments were ordered on the map by comparison of hybridization patterns of the markers with partial NotI cleavages of whole chromosomes. Chromosome rearrangements occur readily in Giardia, and in two drug-resistant lines selected for resistance to different drugs, partial conservative duplications of chromosome 5 were observed in addition to the original, full length chromosome 5. Both duplications retained the central region of chromosome 5 but were deleted at different termini resulting in one duplication of 1.5 Mb and the other of 1.3 Mb.(ABSTRACT TRUNCATED AT 250 WORDS)

Separation and identification of proteins obtained from Agkistrodon acutus snake venom by capillary zone electrophoresis and laser desorption/ionization mass monitoring

Fractions of seven protein principles with fibrinolytic or thrombin-like activities obtained from Agkistrodon acutus snake venom purified by two steps of normal pressure chromatography were separated further by capillary zone electrophoresis (CZE). Mass determination for these fractions were achieved by performing laser desorption/ionization mass monitoring (LDIM). The comparative study between CZE and LDIM on the separation of these fractions was made.

Retinoblastoma protein expression is frequently altered in chronic lymphocytic leukemia

The detection of abnormalities at the retinoblastoma (RB) locus by cytogenetics, Southern blot, and fluorescence in situ hybridization studies suggests that the RB gene has a role in chronic lymphocytic leukemia (CLL). To further study this role, we determined the level of RB protein present in the mononuclear cell fraction derived from peripheral blood or bone marrow samples from 74 patients with CLL, by Western blotting. Compared to similarly prepared samples from the peripheral blood of normal individuals, the level of RB in CLL cells was less than normal in 42% of patients, equal to normal in 22% of patients, and in excess of normal in 36% of patients. Regardless of whether the source of the sample was blood or marrow or if the patients were untreated or previously treated, similar rates of low, normal, and elevated RB levels were observed. RB protein in the CLL patient samples was never phosphorylated. RB levels showed no correlation with the lymphocyte doubling time or with proliferating cell nuclear antigen levels. Low RB levels could arise from genetic alterations of the RB gene or altered regulation of expression. To determine which was occurring, we stimulated the cells from 27 CLL patients in culture with either phytohemagglutinin or pokeweed mitogen in an attempt to induce RB expression and phosphorylation. Among patients with low levels of RB, expression was induced in 46% (6 of 13), and phosphorylation of RB was seen in 31% (4 of 13). Increased expression of phosphorylated RB was induced in 80% (4 of 5) of patients with normal levels of RB and in 78% (7 of 9) of patients with high levels of RB. This study demonstrates that absent RB expression occurs commonly in patients with CLL. Intrinsic abnormalities of the RB gene may be present in those patients with low levels of RB that could not be stimulated by mitogens, while regulatory abnormalities located in trans to the RB gene may occur in the other half. Given the importance that RB levels play in other cancers, the prognostic implication of low RB levels should be studied in CLL.

Phototoxicity of lumidoxycycline

Doxycycline (DOTC) is a photosensitizing drug whose mechanism of phototoxicity is complicated by the large variety of stable photoproducts formed. To assess the role of a DOTC photoproduct, lumidoxycycline (LuDOTC), in the photosensitization mechanism of DOTC, MGH-U1 human bladder carcinoma cells were treated in vitro with either DOTC or LuDOTC, and irradiated with the 351-nm emission of an argon-ion laser. Both DOTC and LuDOTC were phototoxic and caused radiant-exposure-dependent inhibition of cellular incorporation of tritiated thymidine. On an absorbed-photon basis, DOTC was about five times as phototoxic as LuDOTC. Cellular uptake of DOTC was about five times as great as that of LuDOTC. Epifluorescence microscopy showed localization of LuDOTC predominantly within cellular membranes, particularly of mitochondria, as well as a low level of LuDOTC fluorescence diffusely within the cytoplasm. Epifluorescence microscopy of cells labeled with the mitochondrial probe, rhodamine 123, showed mitochondrial fragmentation and altered mitochondrial membrane integrity after LuDOTC photosensitization; these effects depended on radiant exposure and were partially reversible by 24 h after irradiation. For both DOTC and LuDOTC, phototoxicity was increased by irradiation in the presence of deuterium oxide and decreased in the presence of sodium azide, effects consistent with an important mechanistic role for singlet oxygen, O2(1 delta g), in the injury. In solution, LuDOTC and DOTC had similar quantum yields for generation of O2(1 delta g) as measured by time-resolved spectroscopy and by O2(1 delta g) trapping. LuDOTC was photostable in solution, but DOTC underwent significant photodegradation. These data demonstrate that DOTC photo-products such as LuDOTC have significant photobiologic activity and may play an important role in the phototoxicity mechanism of DOTC.

Polyclonal amanitin-specific antibodies: production and cytoprotective properties in vitro

The amanitins found in several mushroom species are responsible for many deaths every year. Based on its successful application to cardiac glycoside overdose, immunotherapy could be applicable to amanitin toxicity. Therefore, we produced polyclonal amanitin antibodies by immunizing rabbits with a novel conjugate of alpha-amanitin. Purified antibodies had an average association constant for alpha-amanitin of 1.3 x 10(9) M-1. A partially protective effect of the antibodies against amanitin toxicity in vitro in Chang cells was evident at a molar ratio of antibody binding sites to alpha-amanitin of 4:1. Together with reported studies in vivo, these investigations indicate the potential of immunotherapy for amanitin poisoning.

High performance liquid chromatographic determination of individual bile acids in serum for automatic diagnosis of various liver and biliary diseases

A reversed phase high performance liquid chromatographic method for the high sensitivity determination of individual bile acids in serum using a C18 column with a ternary solvent system combined with fluorometric techniques using immobilized enzymes is described. A computer-assisted diagnosis system using pattern recognition was developed to assist the clinical diagnosis of various liver and biliary diseases. A total consistency rate of 95% can be reached using this system.

Free-solution capillary electrophoretic separation of small hydrophilic peptides

Small hydrophilic peptides differing in only one glycine amino acid group have been successfully separated by free-solution capillary electrophoresis (FSCE) using phosphate buffer at acid pH. The effects of column temperature and operating current on the migration times of these small peptides have been investigated. The results from FSCE have been compared with those from reversed phase high performance liquid chromatography.

How frequent are hepatitis B virus markers in adult patients with glomerular diseases in a low endemic country? A French study from Paris and Saint-Brieuc

In order to appreciate the frequency of hepatitis B virus (HBV) infection in patients with glomerular diseases in France, a low endemic country, we reviewed the series of patients biopsied in the years 1983-1989 in 2 departments of nephrology differing by the characteristics of the population. In Saint-Brieuc, where the population is almost exclusively Caucasian, with nearly no immigrant, HBsAg was not detected in any of the 86 patients. In Paris, a large number of patients come from highly or intermediately endemic regions. HBsAg was detected in 3 of 209 patients, 2 of the 75 patients with membranous nephropathy and 1 of the 32 patients with minimal-change nephrotic syndrome. These patients came from Africa and Asia. Therefore, in low endemic countries, the role of HBV infection in the etiology of glomerulonephritis is minimal. But, because of the late severity of the disease, screening remains essential in patients belonging to the high-risk groups.

Competition between paraquat and putrescine for uptake by suspensions of rat alveolar type II cells

Paraquat and the structurally similar polyamines, such as putrescine and spermidine, are accumulated actively and selectively by the alveolar type II cells via the polyamine uptake system. We report the uptake kinetics of paraquat and putrescine and their mutual inhibition in freshly isolated rat type II cell suspensions. The uptake of paraquat by type II cells exhibited saturation kinetics and could be inhibited in a concentration-dependent manner by putrescine. By applying enzyme kinetic analysis to our experimental data it was demonstrated that the uptake of paraquat or putrescine is inhibited in a partially competitive manner by the respective inhibitor. Thus, we postulate that the polyamine uptake pathway in type II cells for paraquat and putrescine has two separate sites, one for each substrate, and that binding of one leads to a conformational change in the other.

The retention behaviour of conjugated bile acids in reversed phase high performance liquid chromatography

The retention behaviour of conjugated bile acids has been studied in a reversed phase high performance liquid chromatographic (RP-HPLC) system by using the mixture of methanol and aqueous phosphate buffer as the mobile phase. The retentions of the conjugates in RP-HPLC have been found to be mainly controlled by the glycine and taurine groups. The selectivity between five different glycine and taurine conjugated bile acids is a constant in RP-HPLC. This selectivity has been used for peak identification in the practical separation of conjugated bile acids.

Induction of the major integral membrane protein of mouse liver peroxisomes by peroxisome proliferators

Peroxisome proliferators are known to increase the volume of the peroxisomal compartment in rodent liver. We have examined the induction of the major integral membrane protein of mouse liver peroxisomes (PMP68) by a number of these agents, and compared this with their effect on the peroxisomal bifunctional protein (PBP), an enzyme of the beta-oxidation pathway which is located in the peroxisome matrix. Dietary clofibrate, di-2-(ethylhexyl)phthalate and Wy-14,643, three structurally unrelated proliferators, all increased the mRNA and protein content of PMP68 approx. 2-fold, whereas PBP was induced 8-13-fold. The kinetics and sequence of induction of PMP68 and PBP following a single dose of Wy-14,643 were compared and shown to be similar, and the effects were reversible. Another proliferator, BM 15766, caused maximal induction of PMP68 but only a low induction of PBP; further PBP induction was achieved by the administration of BM 15766 in combination with Wy-14,643. Similarly, BM 15766 and Wy-14,643 increased transcription of the PMP68 gene in vitro, whereas PBP gene transcription was increased by Wy-14,643 but not by BM 15766. Thus peroxisome proliferators enhance the expression of the genes for both the membrane protein PMP68 and the matrix protein PBP, but the regulation of this expression appears to be mediated by different mechanisms.

Azidowarfarin photoaffinity probes of purified rat liver cytochrome P4501A1

Substrate specificity differences between various forms of cytochrome P450 (P450) are governed by substrate binding site amino acid residue differences. To determine the identities of these residues, four analogs of warfarin, a thoroughly investigated anticoagulant drug which is regio- and stereoselectively metabolized by many P450s, have been synthesized as photoaffinity probes. The probes 4'-, 6-, 7-, and 8-azidowarfarin were readily photolyzed in neutral solution by 254-nm light, with half-lives of less than 15 s. When the azidowarfarins were photolyzed in the presence of beta-naphthoflavone-inducible P4501A1 (2.5 microM) at -196 degrees C and the P450 was subsequently reconstituted for warfarin metabolism, 50% inactivation was achieved with 160 microM 4'-azidowarfarin, 64 microM 6-azidowarfarin, 127 microM 7-azidowarfarin, and 29 microM 8-azidowarfarin. This inactivation is irreversible. When these concentrations of the azidowarfarins were photolyzed prior to addition to P4501A1, less inhibition of P450 activity was detected and the inhibition was reversible. The CO-ferrous P450 spectrum of P4501A1 at 448 nm was diminished when photoactivated azidowarfarins bound to and inactivated the enzyme, with essentially no formation of P420 except in the case of 4'-azidowarfarin. The inactivation of P4501A1 by photoactivated 4'-azidowarfarin was prevented by 50% by 1.2 mM R-warfarin or 0.3 mM 4'-nitrowarfarin, consistent with the latter being a better P4501A1 substrate than R-warfarin. The photoinactivation of P4501A1 by each of the azidowarfarins was prevented to variable extents by R-warfarin or by 4'-, 6-, 7-, or 8-nitrowarfarin. Taken together these results demonstrate that all four azidowarfarins are potentially useful photoaffinity probes of the substrate binding site amino acid residues of P450s.

Worldwide perspective of hepatitis B-associated glomerulonephritis in the 80s

Chronic HBsAg carriers may develop glomerulonephritis (GN). Besides membranous GN (MGN), which seems a well established association, membranoproliferative GN (MPGN) or proliferative GN are also encountered in these patients. It is clear that the variations in the incidence of hepatitis B virus (HBV) GN may be real or related to a more or less vigorous search for HBV in the different nephrologic centers. However, the frequency of HBV GN in a country correlates with the underlying prevalence of HBV infection in the general population. Geographic patterns of HBV prevalence vary greatly from areas of low endemicity where less than 1% of adults are chronic carriers to areas of intermediate and high endemicity where between 2 and 15% of adults are chronic carriers. The most important factor affecting prevalence is age of HBV infection. The probability of becoming a chronic carrier is greater following infection during infancy and early childhood. The rarity of HBV GN in the U.S. and in western Europe probably reflects the rarity of HBV infection, especially in children. The frequency of HBV GN is high in Asian or Black children. It is possible to hope that, with the extensive immunization in countries of high endemicity, the frequency of HBV GN will diminish. In the U.S. and in Europe, patients with HBV GN frequently belong to high risk groups for HBV infection. In these countries, the increase in the percentage of HBV infection due to sexual transmission or linked with drug abuse may lead to an increase in the percentage of adult patients with HBV GN.

Light-chain composition of serum IgA1 and in vitro IgA1 production in IgA nephropathy

A predominant expression of IgA1 in mesangial deposits, serum, and bone marrow culture supernatants has been shown in IgA nephropathy (IgAN). Furthermore an excess of lambda light chains in both mesangial deposits and serum IgA has been observed. However, the origin of mesangial IgA remains controversial. In the present study, we have examined the IgA1 light chain type in IgAN. Total IgA1, IgA1 kappa and IgA1 lambda were measured by ELISA in serum and culture supernatants from spontaneous and pokeweed-mitogen (PWM)-stimulated peripheral blood mononuclear cells (PBMC). We observed an increase in IgA and IgA1 serum concentrations in IgA nephropathy patients, with a ratio of serum IgA1 to total serum IgA identical between patients and controls. The concentration of serum IgA kappa did not differ between patients and controls but patients had a significantly higher concentration of serum IgA lambda. The IgA1 kappa to IgA1 lambda ratio was 1.06 +/- 0.42 in IgAN patients versus 1.55 +/- 0.36 in controls (P less than 0.01). By contrast, the concentrations of IgA1 kappa and IgA1 lambda in PBMC culture supernatants, both spontaneous and PWM-stimulated, were identical in patients and controls. Therefore, there is a specific increase in IgA1 lambda in patients' sera. This contrasts with the normal IgA1 production by PBMC, which are derived from mucosal-associated lymphoid tissues. This suggests that IgA isotypic deregulation is confined to the bone marrow compartment and is not a generalised defect of the IgA system.

Effect of central obesity on regulation of carbohydrate metabolism in obese patients with varying degrees of glucose tolerance

It has been proposed that central obesity, by virtue of the enhanced lipolytic activity of abdominal adipose tissue, leads to higher plasma FFA concentrations, which, in turn, decrease both hepatic removal of insulin and insulin-stimulated glucose uptake by peripheral tissues. In short, the predicted consequences of abdominal obesity are elevations in circulating FFA and insulin levels as well as insulin resistance. The goal of this study was to evaluate the relationships predicted by the overall hypothesis; this study was carried out in 31 obese females, defined as having normal glucose tolerance (n = 12), impaired glucose tolerance (n = 8), or noninsulin-dependent diabetes mellitus (n = 11). Abdominal obesity was estimated by determining the ratio of waist to hip girth, fasting and postprandial plasma FFA and insulin concentrations were measured at hourly intervals from 0800-1600 h, and insulin-stimulated glucose disposal was quantified by the euglycemic hyperinsulinemic clamp technique. The first step in the postulated sequence of events to be tested was that the greater the WHR, the higher the total integrated plasma FFA response. The correlation coefficient between these two variables was 0.29, indicating that the results did not support the prediction. Furthermore, we could not demonstrate any relationship between the magnitude of the plasma FFA and insulin responses (r = 0.20; P = NS). However, there was a modest inverse relationship between height of circulating plasma insulin concentration and a decrease in insulin-stimulated glucose uptake (r = -0.43; P less than 0.03) in the group as a whole. On the other hand, when the three groups were analyzed individually, a significant inverse relationship was only seen in the control group (r = -0.67), and a direct relationship was actually seen in patients with impaired glucose tolerance (r = 0.88). Furthermore, when the mean responses for the variables in each of the three groups were compared, it was apparent that the postulated relationships between abdominal obesity, plasma FFA concentration, and insulin secretion and action were not present. Thus, the data presented do not support the hypothesis that differences in the degree of central obesity play an important role in regulation of plasma concentrations of either FFA or insulin or in modulation of insulin-stimulated glucose uptake in the patients we studied.

[Effect of phospholipase A2 on pancreatic parenchymal necrosis in acute pancreatitis in rats]

The effect and mechanism of phospholipase A2 (PLA2) on pancreatic parenchymal necrosis in acute pancreatitis (AP) in rats were studied. Normal saline (NS), PLA2, phosphatidylcholine (PC), and PLA2 mixed PC were respectively injected into the biliopancreatic duct of the rat. The mixture of PLA2 and PC was found to result in necrotizing AP in the rat in 12 hours after injection of the reagent. The lysophosphatidylcholine (LPC) percentage in the amount of PC and LPC and the extent of pancreatic necrosis in this group increased much more significantly than those in other three groups (over about 4 and 15 times). There is evidently positive correlation (r = 0.9001, P less than 0.01) between LPC percentage and necrosis extent. The intraductal injection of PLA2, as well as NS or PC, failed to induce severe morphological changes in the pancreases. These results suggest that PC in bile is necessary in the pathogenesis of biliary pancreatitis and that LPC originated from bile PC by PLA2 may be the initiator in pancreatic parenchymal necrosis in AP.