On the possible use of a new boron compound, hydroxysalicylhydroxamato boron(III), and ultrasound in the treatment of female mice bearing the Ehrlich ascites carcinoma cells

The inhibitory effects of a new boron compound, hydroxy salicylhydroxamato boron (III) (SHB) and ultrasound of frequency 25 KHz (US) on the growth of ascites tumor in female Swiss mice were studied by monitoring the survival and the tumor growth in the treated tumor bearing mice and also the transplantability and the DNA synthesis in the treated tumor (Ehrlich ascites carcinoma) cells. While SHB alone produced a highly significant antitumor activity, US alone produced a small but significant effect. The combination of SHB and US produced significantly greater antitumor activity than SHB alone. The mechanisms of SHB and US actionary are discussed.

Long-term ethanol exposure alters the sialylation index of plasma apolipoprotein J (Apo J) in rats

We have previously shown that chronic ethanol treatment impairs the glycosylation of proteins in the rat liver. Changes in the microheterogeneity of transferrin, a N-sialoprotein under chronic alcohol consumption are well established. Apolipoprotein J, another N-glycoprotein, is a normal component of plasma high-density lipoproteins in the rat and human. Apo J is also highly sialylated and, thus, may be vulnerable to the deleterious actions of ethanol. Therefore, to understand the specific nature of alterations of Apo J sialylation as a consequence of chronic ethanol treatment, we have determined: (1) the sialylation index of Apo J (moles sialic acid per mole Apo J protein) in rats administered ethanol for 4, 6, and 8 weeks and a gradual withdrawal and a follow-up abstinence for 1, 2, and 4 weeks; and (2) enzymatic activities of hepatic sialyltransferase and plasma sialidase during the same periods of alcohol treatment and abstinence in rats. Although no significant differences in the Apo J sialylation index between rats of the control and ethanol groups were found at the 4th week of alcohol treatment, a highly significant loss of 24% (p < 0.001) and 44% (p < 0.001) was found after 6 and 8 weeks, respectively, of alcohol feeding of these animals. Furthermore, a significant recovery of 38% (p < 0.001), 78% (p < 0.001), 84% (p < 0.001) and 96% (p < 0.001) in the sialylation index of Apo J were found, respectively, during withdrawal and 1, 2, and 4 weeks of subsequent alcohol abstinence in these animals. These changes in the sialic acid content of Apo J were accompanied by a similar pattern of changes in the enzyme activities of hepatic sialyltransferase and plasma sialidase in animals undergoing chronic ethanol treatment, withdrawal, and abstinence periods. The analysis of the sialylation index of Apo J seems to be a simple and feasible method to use to evaluate the extent of ethanol exposure.

Divergent effects of dithiocarbamates on AP-1-containing and AP-1-less NFAT sites

Changes in the redox status of cells affect NF-kappaB and activator protein (AP)-1 nuclear expression and activity. In particular, antioxidants decrease NF-kappaB and increase AP-1 transcriptional activity, thereby regulating gene expression. In T cells, low concentrations of antioxidants enhance IL-2 and inhibit IL-4 expression. Since NFAT binding sites play an essential role in regulating IL-2 and IL-4 gene transcription, we studied the effects of dithiocarbamates, using the pyrrolidine derivative of dithiocarbamate (PDTC), on the activity of the distinct AP-1-containing IL-2 NFAT and AP-1-less IL-4 NFAT enhancers elements. Consistent with the presence of AP-1 proteins within the IL-2 NFAT complex, PDTC strongly enhanced phorbol 12-myristate 13-acetate/phytohemagglutinin-induced NFAT binding to the IL-2 NFAT enhancer and transcriptional activity of a reporter plasmid driven by this NFAT enhancer. In contrast, the activity of the IL-4 NFp enhancer, which does not bind AP-1, was abolished by PDTC treatment. In the Jurkat T cell line treated with PDTC, co-expression of the Ca2+/calmodulin-dependent phosphatase, calcineurin, completely restored the IL-4 NFp enhancer activity. Our data indicate that calcineurin-mediated NFAT activity is a target for antioxidants and provides new insights into the molecular mechanisms controlling differential cytokine gene expression.

Effect of chemical nutrients on aconitase activity during citric acid fermentation by a mutant strain of Aspergillus niger

An ethyleneimine and UV irradiated mutant strain Aspergillus niger AB 1801 was explored for its aconitase activity, citric acid production and cell growth during citric acid fermentation. 10% sucrose and 0.25% urea served as the best carbon and nitrogen sources, respectively. Fe2+ stimulated aconitase activity and Co2+ (upto 5 micrograms/mL) and Ni2+ (10 micrograms/mL) strongly depressed enzyme activity. Boric acid (0.5 mg/L) had very good stimulatory response towards citric acid production. Aconitase activity has been found to vary inversely with the citric acid production upto a certain limit after which the activity was absent in the mycelial extract. Cell growth varied with the production parameter.

Molecular genotoxicity profiles of apoptosis-inducing vanadocene complexes

Metallocene complexes containing vanadium induce apoptosis in human cancer cells by an as yet unknown mechanism and may therefore be useful as a new class of cytotoxic anticancer drugs. Ultrastructural studies showing the formation of metallocene-DNA complexes prompted the hypothesis that their mechanism of action may resemble the DNA damage induced by cisplatin. Molecular genotoxicity testing provides insights into the mechanisms of action of new chemotherapeutic agents. Therefore, we determined the effects of three cytotoxic vanadocene complexes, vanadocene dichloride, vanadocene dithiocyanate, and vanadocene dioxycyanate, on genomic stability using the yeast DEL recombination assay and transcriptional activation of genotoxic stress-specific promoters in human HepG2 cells using the CAT-Tox(L) assay. Cisplatin caused an 11-fold increase of recombination frequency in yeast and induced transcriptional activation of the DNA damage-associated promoters such as the minimum promoter containing p53 response elements and the GADD45 promoter in addition to activating the promoters for c-fos, heat shock protein 70, metallothionine IIa, and the minimum promoter containing nuclear factor kappa(kappa)B response elements. In contrast to cisplatin, vanadocene complexes did not increase the DEL recombination frequency in yeast nor did they activate any of the DNA damage-associated promoters in HepG2 cells. Vanadocene complexes triggered activation of the c-fos promoter without affecting the minimum promoter containing p53 response elements or the GADD45 promoter. These results indicate that the apoptotic signal of vanadocene complexes is not triggered by primary DNA damage and it does not require p53 induction, thereby disproving the hypothesis that it mechanistically resembles the cytotoxic action of cisplatin.

The pathobiology of osteoarthritis and the rationale for the use of pentosan polysulfate for its treatment

OBJECTIVES

Structure-modifying osteoarthritis (OA) drugs (SMOADs) may be defined as agents that reverse, retard, or stabilize the underlying pathology of OA, thereby providing symptomatic relief in the long-term. The objective of this review was to evaluate the literature on sodium pentosan polysulfate (NaPPS) and calcium pentosan polysulfate (CaPPS), with respect to the pathobiology of OA to ascertain whether these agents should be classified as SMOADs.

METHODS

Published studies on NaPPS and CaPPS were selected on the basis of their relevance to the known pathobiology of OA, which also was reviewed.

RESULTS

Both NaPPS and CaPPS exhibit a wide range of pharmacological activities. Of significance was the ability of these agents to support chondrocyte anabolic activities and attenuate catabolic events responsible for loss of components of the cartilage extracellular matrix in OA joints. Although some of the anti-catabolic activities may be mediated through direct enzyme inhibition, NaPPS and CaPPS also have been shown to enter chondrocytes and bind to promoter proteins and alter gene expression of matrix metalloproteinases and possibly other mediators. In rat models of arthritis, NaPPS and CaPPS reduced joint swelling and inflammatory mediator levels in pouch fluids. Moreover, synoviocyte biosynthesis of high-molecular-weight hyaluronan, which is diminished in OA, was normalized when these cells were incubated with NaPPS and CaPPS or after intraarticular injection of NaPPS into arthritic joints. In rabbit, canine, and ovine models of OA, NaPPS and CaPPS preserved cartilage integrity, proteoglycan synthesis, and reduced matrix metalloproteinase activity. NaPPS and CaPPS stimulated the release of tissue plasminogen activator (t-PA), superoxide dismutase, and lipases from vascular endothelium while concomitantly decreasing plasma levels of the endogenous plasminogen activator inhibitor PAI-1. The net thrombolytic and lipolytic effects exhibited by NaPPS and CaPPS may serve to improve blood flow through subchondral capillaries of OA joints and improve bone cell nutrition. In geriatric OA dogs, NaPPS and CaPPS reduced symptoms, as well as normalized their thrombolytic status, threshold for platelet activation, and plasma triglyceride levels. These hematologic parameters were shown to be abnormal in OA animals before drug treatment. Similar outcomes were observed in OA patients when CaPPS or NaPPS were given orally or parenterally in both open and double-blind trials.

CONCLUSIONS

The data presented in this review support the contention that NaPPS and CaPPS should be classified as SMOADs. However, additional long-term clinical studies employing methods of assessing joint structural changes will be needed to confirm this view.

A new boron compound (guanidine biboric acid adduct) as an antitumour agent against Ehrlich ascites carcinoma in mice

The inhibitory effects of a new boron compound of guanidine biboric acid adduct (GB) and guanidium chloride (L1) on the growth of ascites tumour in female Swiss mice were studied by monitoring the survival, tumour weight, tumour cell count, transplantability of Ehrlich ascites cells, precursor incorporation and the haematological parameters of the treated mice. 5-Fluorouracil, a known anticancer drug, was used as a positive control. The most important parameter was the survival time, which increased significantly when tumour-bearing mice were treated with the boron compound. Haematological parameters of the treated animals showed minimum toxic effects when boron was coupled with guanidine.

Offspring of normal and diabetic rats fed saturated fat in pregnancy demonstrate vascular dysfunction

BACKGROUND

Disturbances of the in utero environment may "program" for disease in later life. In this study, we determined whether dietary fat supplementation and/or diabetes in pregnancy can adversely affect vascular function in the offspring.

METHODS AND RESULTS

Female Sprague-Dawley rats were fed a breeding diet or a diet high in saturated fat (30% wt/wt) for 10 days before mating, throughout pregnancy, and postpartum. Endothelium-dependent relaxation to acetylcholine was blunted in isolated femoral arteries of 15-day-old weanling pups from dams fed the 30%-fat diet. Endothelial dysfunction and enhanced constrictor responses to norepinephrine were also observed in an additional study of 60-day-old offspring of dams fed 20% saturated fat. Rats with streptozotocin-induced diabetes were also fed saturated fat during pregnancy. Femoral arteries from their 15-day-old offspring showed impairment of endothelium-dependent dilation and enhanced constrictor responses to norepinephrine and the thromboxane mimetic U46619 compared with young offspring of high-fat-fed normal dams. The 30%-fat diet was also deleterious to vascular function in the maternal diabetic animals when assessed in mesenteric arteries 16 days postpartum.

CONCLUSIONS

A high-fat diet in pregnancy led to vascular dysfunction in rat weanlings and young adult offspring. Vascular function further deteriorated in weanlings if the maternal rat was diabetic.

Pathogenesis of abdominal aortic aneurysms: possible role of differential production of proteoglycans by smooth muscle cells

PURPOSE

In vivo and in vitro observations strongly suggest that marked differences exist in the phenotype, growth, and matrix-producing capabilities of distinct smooth muscle cell subpopulations. An earlier study from our laboratory showed differences in matrix metalloproteinase expression patterns in cultures of medial smooth muscle cells from tissue affected by abdominal aortic aneurysm (AAA) or atherosclerotic occlusive disease and from normal arterial tissue. In this study we were interested in ascertaining whether smooth muscle cells from the same sample groups also synthesized different proteoglycan profiles that correlated with vascular disease.

METHODS

Proteoglycans from smooth muscle cell monolayer cultures from tissue affected by AAA or atherosclerotic occlusive disease and from normal arterial tissue were examined by means of immunoblotting and affinity-blotting composite agarose polyacrylamide gel electrophoresis (CAPAGE) and sodium dodecyl sulphate PAGE. Enzyme-linked immunosorbent assay (ELISA) was used to quantitate perlecan levels in smooth muscle cell monolayer media samples.

RESULTS

Versican, perlecan, and biglycan levels were significantly elevated in AAA smooth muscle cell cultures. Two populations of smooth muscle cell versican were identified by means of CAPAGE-immunoblotting and by means of a novel affinity-blotting technique with biotinylated hyaluronan. A small keratan sulfate-substituted proteoglycan was present in similar levels in all smooth muscle cell cultures. This proteoglycan had a free core protein of about 55 kd after keratanase digestion and had a relatively high charge-to-mass ratio, as was evident from its electrophoretic mobility in CAPAGE; this proteoglycan was tentatively identified as keratocan. Immunoblotting with monoclonal antibodies 3-G-10 (anti-delta heparan sulfate, heparan sulfate stubs generated by heparitinase treatment) and 10-E-4 (anti-native heparan sulfate chains) helped identify several smooth muscle cell heparan sulfate-substituted proteoglycans. Elevated levels of intact and processed perlecan core protein were identified in AAA cultures by means of immunoblotting with a monoclonal antibody to perlecan core protein (A76). ELISA measurements confirmed that perlecan levels were significantly higher in AAA smooth muscle cell cultures compared with the normal arterial tissue and tissue affected by atherosclerotic occlusive disease.

CONCLUSIONS

Because heparan sulfate proteoglycans can bind growth factors, their elevated synthesis by AAA smooth muscle cells in combination with an increased expression of matrix metalloproteinases may at least partly explain the differential proliferative capacity of the AAA smooth muscle cells examined and may govern the pattern of abnormal cellular proliferation and matrix protein synthesis observed in the pathogenesis of vascular disease.

Structural and biological characterization of a novel spermicidal vanadium(IV) complex: bis(pi-cyclopentadienyl)-N,N-diethyl dithiocarbamato vanadium(IV) tetrafluoro borate, [VCp2(DeDtc)](BF4)

In a systematic search for vanadocene complexes with sperm immobilizing activity as a new class of contraceptive agents, we identified V(eta 5-C5H5)2((C2H5)2 NCS2)(BF4) (=[VCp2(DeDtc)](BF4)) as the most potent and stable spermicidal compound. Here we report the detailed biologic and physicochemical characterization of this lead spermicidal compound by computer-assisted sperm analysis, electron paramagnetic resonance spectroscopy, electrochemistry, and X-ray crystallography. [VCp2(DeDtc)](BF4) crystallized in the monoclinic space group P2(1)/c, with unit cell dimensions a = 7.0877(4) A, b = 22.2881(14) A, c = 11.8021(7) A, beta = 94.107(1) degree, V = 1859.6(2) A3. The final structure of [VCp2(DeDtc)](BF4) had an R factor of 0.0581 for 3191 independent reflections. The two sulfur atoms of the dithiocarbamate and centroids of the cyclopentadienyl rings in this vanadocene complex with unique contraceptive potential occupy four tetrahedral--like coordination sites about the central metal atom.

Small aortic annulus: a functional definition

BACKGROUND & OBJECTIVE

Small aortic annulus is conventionally associated with poor outcome after aortic valve replacement (AVR). Contrarily, several patients have excellent follow-up results after AVR with 19, 20 or 21 size Medtronic Hall (MH) or Sorin Carbocast (SC) prostheses. This disparity prompted a relook at the semantics of a small aortic annulus.

METHODS

Available survivors of isolated AVR with #19, #20 or #21 prostheses - 13 with 19 SC or 20 MH valves (Group A) and 29 with 21 SC or MH valves (Group B) were studied. Disparity between actually implanted prostheses versus predicted prosthetic size (tissue annulus diameter) was analysed according to nomograms of Rowlatt et al, NIH Plehn, Kishimoto formula and Sievers composite criteria. Preoperative and follow-up echocardiographic assessments were used for hemodynamic and prosthetic function indices.

RESULTS

Both groups were similar in age, height, weight, BSA, BMI, mean NYHA class, CTR, preoperative peak gradient (PG) (92. 0 +/- 29.55 vs 102.88 +/- 33.65), mean gradient (MG) (56.8 +/- 24.6 vs 61.55 +/- 16.56), LVEDD (50.75 +/- 10.92 vs 56.0 +/- 13.5), LVESD (34.37 +/- 13.32 vs 38.52 +/- 13.85) and LVEF (67.5 +/- 12.5 vs 63.9 +/- 14.3). By developmental indices of Rowlatt et al. and NIH, no valve annulus could be designated as narrow. By Sievers composite nomogram all implanted valves were undersized by echocardiographic parameters, in normal range by angiographic criteria and oversized by anatomic autopsy data. Implanted valves in both groups were bigger than Plehn-predicted size (18.16 +/- 1.48 in GrA, 19.46 +/- 1. 10 in GrB). Valve size indices (VSI) (GrA 16.16 +/- 2.85 GrB 14.24 +/- 1.64) and geometric orifice area indices (VAI: valve area index) (GrA 1.50 +/- 0.28 vs 1.41 +/- 0.19) and postoperative rest PG (GrA 47.2 +/- 18.6 GrB 33.8 +/- 9.9) and MG (GrA 27.2 +/- 12.9 vs 19.0 +/- 9.9) were acceptable. LVEDD and LVESD regressed in both groups. LV mass indices regressed from 218.56 +/- 100.85 to 128.17 +/- 27.7 in GrA and 238.94 +/- 102.5 to 134.22 +/- 34.72 in GrB. Performance indices of implanted valves and postoperative aortic valve resistances were correlative.

CONCLUSIONS

The size of the implanted prostheses per se does not denote narrowness. Patient-prosthesis mismatch may be considered if predicted prosthesis has VSI <12 mm/m2, VAI <1.31 cm2/m2 or prosthesis orifice diameter <19 mm which may indicate annular enlargement.

Long-term ethanol consumption selectively impairs ganglioside pathway in rat brain

Gangliosides are sialo-glycosphingolipids that play important roles in the interaction of cells with their environment and are thus involved in the regulation of many cellular events. Sialic acid residues are important for the conformation of a glycomolecule, their structural stability and their functions. Although decreased brain ganglioside sialic acid has been previously reported as a result of chronic ethanol treatment in rats, no reports are available on the sialylation of specific gangliosides and/or the mechanism leading to depletion of their sialic acid residues. Therefore, in this investigation, we have examined the effects of chronic ethanol treatment on (1) incorporation of [4,5-3H]N-acetylmannosamine (ManNAc) into specific rat brain gangliosides, GD3, GD1a, GT1a, and GT1b; and (2) enzymatic activities of brain sialyltransferase and sialidase at specific subcellular levels. The experiments were done in male Wistar rats pair-fed with either ethanol or control liquid diets for a period of 8 weeks. The rats were intracerebroventricularly injected with labeled ManNAc (30 microCi/rat) and killed after 90 min. Radioactivity was determined in respective ganglioside bands separated on a thin layer chromatography system. Specific activities of sialyltransferase and sialidase were assessed using GM3 and GD3 as substrates, respectively. The results showed significant decreases of 57.7% (p < 0.001) and 68.9% (p < 0.001), respectively, in the labeled ManNAc incorporation into GD3 and GD1a fractions in rats of the ethanol group, compared with rats of the control group. No significant changes were noted in the incorporation of labeled ManNAc into GT1a or GT1b ganglioside fractions between the ethanol and control groups. Concomitantly, compared with control rats, a decrease of 18.9% (p < 0.05), 20.6% (p < 0.05), and 15.8% (p < 0.001) was found in the sialyltransferase activity, respectively, at the whole brain, and brain Golgi and synaptosomal levels. However, dramatic increases of 32.4% (p < 0.05), 105% (p < 0.001), and 150% (p < 0.001) in sialidase activity were found, respectively, at the whole brain and brain cytosol and synaptosomal fractions of rat treated chronically with ethanol. Thus, we conclude that the deleterious actions of ethanol on the sialylation of rat brain gangliosides is specific, and the reduced sialic acid label found in GD3 and GD1a in this study is mainly due to increased activity of brain sialidase. Furthermore, the study reaffirms our tenet that, regardless of whether it is the liver or the brain, glycosylation cascade is one of the main target of the deleterious attacks of ethanol.

Antitumor properties of boron complexes with hydroxy biguanide and salicyl hydroxamic acid against Ehrlich ascites carcinoma

A new derivative of hydroxamic acid, hydroxy biguanido hydrochloride monohydrate and its boron derivative, dihydroxy-oxybiguanido boron (III) hydrochloride monohydrate were synthesized. Another boron compound, hydroxo-salicyl-hydroxamato boron (III) was synthesized from known salicyl hydroxamic acid. Antitumor properties of all the compounds evaluated against Ehrlich ascites carcinoma in mice show enhanced survival time when boron is incorporated in the compounds. Hematological parameters, alkaline phosphatase in serum of the treated animals show minimum toxic effects after boron is coupled with their respective hydroxamic acids.

Spermicidal activity of chelated complexes of bis(cyclopentadienyl)vanadium(IV)

Transition metal complexes containing vanadium IV have been shown to modulate the cellular redox potential and catalyse the generation of reactive oxygen intermediates (ROI). Since sperm function is exquisitely susceptible to ROI, we examined the effects of stable chelate complexes of vanadocenes on human sperm motility. We synthesized seven structurally distinct chelate complexes of bis(cyclopentadienyl)vanadium(IV) with bidentate ligands [i.e. vanadocene acetylacetonato monotriflate (VDacac), vanadocene hexafluoro acetylacetonato monotriflate (VDHfacac), vanadocene N-phenyl benzohydroxamato monotriflate (VDPH), vanadocene acethydroxamato monotriflate (VDH), vanadocene catecholate (VDCAT), vanadocene bipyridino ditriflate (VDBPY), and vanadocene dithiocarbamate monotriflate (VDDTC)], and evaluated their spermicidal activity using computer-assisted sperm analysis (CASA; Hamilton-Thorne). All seven chelate complexes of vanadocene elicited potent spermicidal activity at micromolar concentrations (EC50 values: 3.9-106 microM) without affecting the sperm acrosome integrity. The catecholate and acetylacetonate complexes of vanadocene were the most active and the bipyridyl complex the least active with an order of efficacy VDCAT > VDacac > VDDTC > VDPH > VDH > VDHfacac > VDBPY. The spermicidal activity of chelate complexes of vanadocenes was rapid and irreversible since the treated spermatozoa underwent apoptosis, as determined by the flow cytometric analysis of mitochondrial membrane potential, surface annexin V binding assay, in-situ nick-end labelling of sperm nuclei, and confocal laser scanning microscopy. These results provide unprecedented evidence that chelate complexes of vanadocene with bidentate ligands have spermicidal and apoptosis inducing properties. These vanadocene complexes, especially VDacac, may be useful as contraceptive agents.

Spermicidal activity of metallocene complexes containing vanadium(IV) in humans

We have used computer-assisted sperm analysis (CASA) to evaluate the spermicidal activity of 8 metallocene dihalides (vanadocene dichloride [VDC], titanocene dichloride [TDC], zirconocene dichloride [ZDC], molybdocene dichloride [MDC], hafnocene dichloride [HDC], vanadocene dibromide [VDB], bis[methylcyclopentadienyl] vanadium dichloride [VMDC], and vanadocene diiodide [VDI]); 5 vanadocene di-pseudohalides (vanadocene diazide [VDA], vanadocene dicyanide [VDCN], vanadocene dioxycyanate [VDOCN], vanadocene dithiocyanate [VDSCN], and vanadocene diselenocyanate [VDSeCN]); and 3 disubstituted derivatives (vanadocene ditriflate [VDT], vanadocene monochloro oxycyanate [VDCO], and vanadocene monochloro acetonitrilo tetrachloro ferrate [VDFe]). Whereas the metallocene complexes containing titanium, zirconium, molybdenum, and hafnodium were inactive, all 12 vanadocene complexes elicited potent spermicidal activity at nano-micromolar concentrations with an order of efficacy VDSeCN > VDSCN > VDB > VMDC > VDCN > VDA > VDC > VDOCN > VDI > VDT > VDFe > VDCO without disrupting the acrosomal membrane, as determined by high-resolution low-voltage scanning electron microscopy. The sperm-immobilizing activity of the vanadocene complexes was rapid and irreversible, since the treated sperm underwent apoptosis as determined by the flow cytometric annexin V binding assay, DNA nick end-labeling, and confocal laser scanning microscopy. These results provide unprecedented evidence that metallocene complexes containing vanadium(IV), especially VDSeCN, may be useful as contraceptive agents.

Proteinase activity & virulence of Entamoeba histolytica on passage through hamster liver

This study was undertaken to determine the enzymatic differences in the process of increasing the degree of virulence in E. histolytica successively passaged in hamster liver. Substrate gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of one axenic E. histolytica (strain HM1:IMSS) and five xenic isolates of the same strain of E. histolytica passaged five times through hamster liver. Trophozoites successively passaged in hamster liver showed in supernatants, major bands in the 56-97 kDa region whereas only the axenic strain produced additional band at 34 KDa. Inoculation of amoebic trophozoites into hamster led to progressive increase in proteinase activity of supernatants as well as increased virulence of amoebae; proteinase activity of amoebae showed an excellent correlation with their virulence. All the infected animals died when activity of proteinase was 0.152 mg of protein.

Deleterious actions of chronic ethanol treatment on the glycosylation of rat brain clusterin

Clusterin is a N-glycosylated sialoglycoprotein present in rat brain cells. Clusterin, which elicits aggregation in a wide variety of cells, has been suggested to play an important role in synaptic remodeling through its cell adhesion property or lipid transport capacity in the brain. Sialic acid residues in clusterin may be responsible for its structural conformation, stability and functional ability. Maturation of clusterin is governed by the relative actions of sialyltransferases and sialidases that are present in brain microsomes, golgi bodies, cytosol and plasma membranes. We have earlier reported that chronic ethanol treatment in rats has a damaging effect on the hepatic glycosylation machinery. Others have reported increased hydrolysis of brain sialoconjugates in rats following chronic ethanol administration. Specificity of the effects of chronic ethanol treatment in the brain in relation to the glycosylation process, is still obscure. Therefore, in this investigation, we have studied the specific effects of chronic ethanol treatment on the glycosylation of rat brain clusterin and the causes that may lead to any possible defects in the glycosylation process. We have determined the effects of chronic ethanol treatment on (i) the incorporation of labeled leucine and N-acetylmannosamine into immunoprecipitable clusterin in whole brain homogenate, microsomes, golgi, cytosol, plasma membrane and synaptosomes, (ii) enzymatic activities of sialyltransferases in golgi and synaptosomes, and sialidase in brain cytosol and plasma membranes, and (iii) de novo synthetic rate of rat brain cytosolic sialidase. Our results showed that chronic ethanol treatment in rats resulted in (1) a decreased sialation index of brain clusterin by 47. 2% (p<0.001), 56.7% (p<0.05), 51.7% (p<0.05), 64.8% (p<0.001), and 54.5% (p<0.05), respectively, in whole brain homogenate, golgi, cytosol, plasma membranes, and synaptosomes; (2) a 46.1% (p<0.05) and 12.5% (p<0.05) decreased activities of brain sialyltransferases, respectively, in the golgi and the synaptosomal fractions; (3) a 70. 1% (p<0.05) and 42.6% (p<0.05) increased activities of sialidases, respectively, in the cytosol and plasma membrane fractions; and (4) a 22.2%-64.3% (p<0.001) increased incorporation of labeled leucine into brain cytosolic sialidase. Our findings have clearly established that long-term ethanol treatment in rats leads to a marked impairment in the glycosylation of rat brain clusterin as a result of altered activities of brain sialation and desialation enzymes. In particular, the specific increase noted in brain sialidase activity was due to concomitant increases in its synthetic rate. These defects in the glycosylation of brain clusterin may lead to changes in the molecular conformation of clusterin, and thus, may result in its structural instability and/or functional impairment.

Detection of aggregatable proteoglycan populations by affinity blotting using biotinylated hyaluronan

Proteoglycans (PGs) were extracted from a range of cartilaginous ovine connective tissues using 4 M GuHCl and separated by composite agarose polyacrylamide gel electrophoresis. Individual PG populations resolved by this electrophoretic system were identified in toluidine blue and Stains-All stained gel segments and also by conventional immunoblotting using a range of monoclonal antibodies to defined PG epitopes. These PG species were compared with aggregatable PG populations identified by affinity blotting using a biotinylated hyaluronan, and an avidin alkaline phosphatase/nitro blue tetrazolium 5-bromo-4-chloro indolyl phosphate detection system. Two major chondroitin sulfate- and keratan sulfate-substituted aggrecan populations were readily identified by affinity blotting in all of the connective tissue extracts. An additional slower migrating aggrecan species was also detected by affinity and immunoblotting in fetal disc extracts. This may represent an aggrecan species containing an intact carboxyl terminal G3 domain. Link protein was also detectable by affinity blotting; this was confirmed by immunoblotting using an anti-link protein monoclonal antibody (8-A-4). Fragments of aggrecan which contained a functional G1 domain were also detectable by affinity blotting. The biotinylated hyaluronan affinity blotting technique could detect as little as 100 ng (as hexuronic acid) of aggregatable PG. Affinity blotting therefore represents a useful new detection methodology which complements conventional immunoblotting protocols and yields information regarding the functional status of the G1 domain of individual PG populations.

Changes in expression of signal transduction proteins in T lymphocytes of patients with leprosy

Advanced stages of mycobacterial diseases such as leprosy and tuberculosis are characterized by a loss of T-cell function. The basis of this T-cell dysfunction is not well understood. The present report demonstrates major alterations in the expression of signal transduction molecules in T cells of leprosy patients. These alterations were most frequently observed in lepromatous leprosy (LL) patients. Of 29 LL patients, 69% had decreased T-cell receptor zeta-chain expression, 48% had decreased p56(lck) tyrosine kinase, and 63% had a loss of nuclear transcription factor NF-kappaB p65. An electrophoretic mobility shift assay with the gamma interferon core promoter region revealed a loss of the Th1 DNA-binding pattern in LL patients. In contrast, tuberculoid leprosy patients had only minor signal transduction alterations. These novel findings might improve our understanding of the T-cell dysfunction observed in leprosy and other infectious diseases and consequently might lead to better immunologic evaluation of patients.