Saccharomyces boulardii for the treatment of Clostridium difficile-associated colitis

S. boulardii has been investigated in Europe and the US, and preliminary reports indicate that it is safe and effective in conjunction with vancomycin or metronidazole for the treatment of CDC, predominantly in patients who develop recurrence. S. boulardii in combination with vancomycin or metronidazole has not been shown to be more effective than either of these agents alone for treatment of a first episode of CDC. In addition, S. boulardii has not been studied in immunocompromised patients who may be at risk for developing fungemia. Ultimately, large-scale clinical studies are necessary to determine whether S. boulardii should be routinely used to treat patients with recurrent CDC. S. boulardii is currently undergoing Phase III clinical trials for CDC treatment in the US. Clinicians interested in information regarding participation in current studies may contact Biocodex Inc., in Seattle, Washington.     

Regulation of hepatic glutaminase in the streptozotocin-induced diabetic rat

The liver of diabetic animals removes increased quantities of glutamine. We therefore examined factors that affect hepatic glutaminase activity in hepatocytes and mitochondria. Glutamine use, through glutaminase, was measured in isolated rat hepatocytes by monitoring the production of 14CO2 from [1-(14)C]glutamine. Hepatocytes from streptozotocin-induced diabetic rats use glutamine more rapidly than do hepatocytes from normal or insulin-maintained diabetic rats. Glutamine use in all of these hepatocytes was stimulated by glucagon and epinephrine. Glutaminase activity, assayed in broken mitochondrial membranes, was increased approximately 2.5-fold in diabetic rats. The sensitivity of glutaminase, measured in intact liver mitochondria, to phosphate was markedly left-shifted in mitochondria from diabetic rats compared with those from controls. In fact, glutaminase was increased 10-fold at 2.5 mmol/l phosphate compared with controls. This increased sensitivity of glutaminase to physiological concentrations of phosphate is characteristic of its hormonal activation. Therefore, activation of glutaminase plays a major role in diabetes and is as important as increases in its total enzyme amount in determining the increased glutamine uptake in diabetes.     

Targeted gene delivery by tropism-modified adenoviral vectors

The utility of adenoviral vectors for gene therapy is currently limited due, in part, to the widespread distribution of the cellular receptor for the adenovirus fiber that precludes the targeting of specific cell types. In order to develop a targeted adenovirus, it is therefore necessary both to ablate endogenous viral tropism and to introduce novel tropism. We hypothesized that these two goals could be achieved by employing a neutralizing anti-fiber antibody, or antibody fragment, chemically conjugated to a cell-specific ligand. To test this concept, we chose to target the folate receptor, which is overexpressed on the surface of a variety of malignant cells. Therefore, we conjugated folate to the neutralizing Fab fragment of an anti-fiber monoclonal antibody. This Fab-folate conjugate was complexed with an adenoviral vector carrying the luciferase reporter gene and was shown to redirect adenoviral infection of target cells via the folate receptor at a high efficiency. Furthermore, when complexed with an adenoviral vector carrying the gene for herpes simplex virus thymidine kinase, the Fab-folate conjugate mediated the specific killing of cells that overexpress the folate receptor. This work thus represents the first demonstration of the retargeting of a recombinant adenoviral vector via a non-adenoviral cellular receptor.     

The in vitro antioxidant activity of trilinolein and other lipid-related natural substances as measured by enhanced chemiluminescence

There is abundant evidence for the premise that oxygen-derived free radicals (OFR) mediate ischemia/reperfusion injury to the myocardium. OFR scavengers such as superoxide dismutase can effectively reduce damage through lipid peroxidation during ischemia/reperfusion. Enhanced chemiluminescence, which has been used to measure OFR, was used to measure the antioxidant activity of fatty acids (palmitic and linoleic acid) and triglycerides (triolein, tristearin) and natural plant antioxidants (magnolol, catechin, trilinolein). Trilinolein, which has recently been isolated from natural products, as well as the well-known water soluble analogue of vitamin E-Trolox, were used as control. During pretreatment with chemicals, at concentrations of 10(-9) to 10(-7) M, enhanced chemiluminescence of linoleic acid (C 18:2) showed a dose-responsive reduction of OFR with a maximal mean reduction of -31.9% when compared to baseline. A saturated fatty acid such as palmitic acid (C 16:0) showed only relatively weak antioxidant activity at concentrations of 10(-7) to 10(-6) M with a maximum reduction of OFR of- 15.2% only. control chemicals such as trilinolein and Trolox showed significant antioxidant activity. At concentrations between 10(-10) and 10(-6) M and trilinolein has the most potent antioxidant activity with a maximal mean reduction of OFR of -48.0%, whereas Trolox showed only -39.2%. As for the natural plant antioxidants, only catechin showed potent antioxidant activity (-40%). Polyunsaturated triglycerides such as triolein (oleic acid, C 18:1) also possess significant OFR scavenging effect (-31.9%) whilst saturated triglycerides such as tristearin (stearic acid, C 18:0) had only relatively weak antioxidant activity (-15.2%). Generally, the antioxidant activity of unsaturated compounds is stronger than saturated compounds; double-bond existence may partially explain this phenomenon.     

Characterization of native and recombinant bone sialoprotein: delineation of the mineral-binding and cell adhesion domains and structural analysis of the RGD domain

Bone sialoprotein is a small, sulfated, and phosphorylated integrin-binding glycoprotein apparently found only in tissues that eventually mineralize. Nondenatured bone sialoprotein (BSP) purified from rat osteosarcoma cell line (UMR 106-01 BSP) culture media is shown to have a hydroxyapatite Kd approximately 2.6 x 10(-9) M, perhaps the strongest affinity for this mineral of any of the matrix proteins. Both native BSP and a 47 kD fragment of UMR-BSP (Fragment 1 approximately 133A- approximately 265Y) are more potent inhibitors of seeded hydroxyapatite crystal growth than recombinant human BSP fragments lacking post-translational modifications. The recombinant proteins, however, do show reproducible inhibitory activity, suggesting that at least some of the strong mineral-binding properties are encoded directly within the protein sequence itself. BSP facilitates the adhesion of several cell types through its integrin binding (RGD) tripeptide sequence. Nuclear magnetic resonance (NMR) analysis of a 15N-enriched 59 amino acid recombinant domain containing the RGD tripeptide shows that the structure of this isolated domain is highly flexible with or without 5 mM calcium. Previous work has also shown that an endogenous fragment of UMR-BSP (Fragment 1) supports cell adhesion in the absence of the RGD sequence. In this report, non-RGD cell adhesion sites are localized within conserved amino- and carboxy-terminal tyrosine-rich domains of recombinant human BSP. Given the proximity of the latter non-RGD cell adhesion site to the RGD tripeptide, a model of BSP-receptor interactions is presented.     

Positive feedback and angiogenesis in tumor growth control

In vivo tumor growth data from experiments performed in our laboratory suggest that basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are angiogenic signals emerging from an up-regulated genetic message in the proliferating rim of a solid tumor in response to tumor-wide hypoxia. If these signals are generated in response to unfavorable environmental conditions, i.e. a decrease in oxygen tension, then the tumor may play an active role in manipulating its own environment. We have idealized this type of adaptive behavior in our mathematical model via a parameter which represents the carrying capacity of the host for the tumor. If that model parameter is held constant, then environmental control is limited to tumor shape and mitogenic signal processing. However, if we assume that the response of the local stroma to these signals is an increase in the host's ability to support an ever larger tumor, then our models describe a positive feedback control system. In this paper, we generalize our previous results to a model including a carrying capacity which depends on the size of the proliferating compartment in the tumor. Specific functional forms for the carrying capacity are discussed. Stability criteria of the system and steady state conditions for these candidate functions are analyzed. The dynamics needed to generate stable tumor growth, including countervailing negative feedback signals, are discussed in detail with respect to both their mathematical and biological properties.     

Malignant hepatic tumours associated with previous exposure to Thorotrast: four cases

This report concerns four patients in a district general hospital who died from malignant liver tumours associated with Thorotrast (thorium dioxide) deposits in the liver. Three were known to have had diagnostic angiographic studies performed 36 to 43 years previously using Thorotrast as the contrast agent. In the fourth case no previous relevant information could be obtained. There were two men and one woman with hepatocellular carcinoma and one woman with cholangiocarcinoma. In one of the hepatoma cases there was associated hypercalcaemia of malignancy. Reported latency intervals suggest that cases of Thorotrast-related hepatic malignancy may present up to the second decade of the twenty-first century.     

Clinical value of triple-energy window scatter correction in simultaneous dual-isotope single-photon emission tomography with 123I-BMIPP and 201Tl

To improve the image quality in simultaneous dual-isotope single-photon emission tomography (SPET) with iodine-123 labelled 15-(p-iodophenyl)-3-methylpentadecanoic acid (BMIPP) and thallium-201, we applied the triple-energy window method (TEW) for correction of the cross-talk and scatter artifact. Seventy-one patients with coronary artery disease were included. 201Tl cross-talk into the 123I acquisition window (group 1, n = 30) and 123I cross-talk into the 201Tl window (group 2, n = 41) were studied. In group 1, 123I images were first obtained (single-isotope images), followed by 201Tl injection and SPET acquisition using dual-isotope windows (dual-isotope images). In group 2, the order was reversed. The dual-isotope SPET images with and without TEW were compared with the single-isotope images. Qualitative evaluation was performed by scoring the segmental defect pattern. Detectability of the mismatched fatty acid metabolism on dual-isotope SPET was evaluated by receiver operating characteristic (ROC) curve analysis. Segmental defect pattern agreement between dual and corrected single images was significantly improved by TEW correction (P<0.01). The agreement was particularly improved in segments with absence of uptake. There was no significant difference between TEW-corrected dual-isotope SPET and corresponding single-isotope SPET with regard to either % defect count or background activity. Mismatched fatty acid metabolism depicted by dual-isotope SPET predicted abnormal wall motion more accurately with TEW than without TEW. With TEW, a practical method for scatter and cross-talk correction in clinical settings, simultaneous dual 123I-BMIPP/201Tl SPET is feasible for the assessment of myocardial perfusion/metabolism mismatch.     

Characterization of SCML1, a new gene in Xp22, with homology to developmental polycomb genes

BACKGROUND: Mixed hematopoietic chimerism induced with a nonmyeloablative conditioning regimen leads to donor-specific transplantation tolerance. Analyses of specific Vbeta-bearing T-cell families that recognize endogenous superantigens demonstrated that donor-specific tolerance is due mainly to an intrathymic deletional mechanism in these mixed chimeras. However, superantigens are not known to behave as classical transplantation antigens. We therefore used T-cell receptor (TCR) transgenic (Tg) recipients expressing a clonotypic TCR specific for an allogeneic major histocompatibility complex antigen to further assess deletional tolerance. METHODS: 2C TCR Tg mice (H2b), whose Tg TCR recognizes major histocompatibility complex class I Ld, were used as recipients of Ld+ bone marrow cells after conditioning with depleting anti-CD4 and CD8 monoclonal antibodies, 3 Gy whole-body irradiation, and 7 Gy thymic irradiation. Chimerism and deletion of CD8+ 2C recipient T cells was evaluated by flow cytometry and by immunohistochemical staining. Tolerance was tested with in vitro cell-mediated lympholysis assays and in vivo by grafting with donor skin. RESULTS: Intrathymic and peripheral deletion of 2C+ CD8-single-positive T cells was evident in mixed chimeras, and deletion correlated with the presence of donor-type cells with dendritic morphology in the thymus, and with chimerism in lymphohematopoietic tissues. Chimeras showed tolerance to the donor in cell-mediated lympholysis assays and specifically accepted donor skin grafts. CONCLUSIONS: Tolerance to transplantation antigens is achieved through intrathymic deletion of donor-reactive T cells in mixed chimeras prepared with a nonmyeloablative conditioning regimen and allogeneic bone marrow transplantation.     

Radiographic outcome of recent-onset rheumatoid arthritis: a 19-year study of radiographic progression

OBJECTIVE: To describe the longitudinal radiographic course of rheumatoid arthritis (RA), and to identify and quantitate predictors of radiographic progression. METHODS: This prospective, longitudinal study of radiographic progression and clinical predictors of RA involved 256 patients with RA who were seen within the first 2 years of disease (mean 0.77 years) and were followed up for up to 19 years. Participants underwent a total of 6,278 clinical assessments (mean 24.5) and 934 paired radiographs (mean 3.1, range 2-6). Clinical assessments at every visit included determination of the erythrocyte sedimentation rate (ESR), grip strength, pain scores, tender joint counts, and anxiety and depression measurements. Regression analyses utilized time-integrated predictors. RESULTS: Overall, radiographic progression rates, as measured by the summary Sharp scores, appeared constant over the course of RA. The strongest correlate of progression was the time-integrated ESR (rho=0.53). This association grew stronger with time. At 0-5 years, 5-10 years, 10-15 years, and 15-20 years, correlations were 0.40, 0.50, 0.65, and 0.74, respectively, and for the period 10-20 years, the correlation was 0.67. In multivariate models, the mean ESR, mean grip strength, rheumatoid factor positivity, and tender joint count were independent predictors of radiographic progression. CONCLUSION: Radiographic damage occurs at a constant rate in RA, and is not greater early in RA or reduced later in the course of the illness. Acute-phase reactants are, by far, the strongest determinants of progression.