Fas Ligand-dependent and -independent mechanisms of toxicity induced by T cell lymphomas in lymphoid organs and in the liver

In the current study, we investigated the effect of growth of FasL⁺ tumors in vivo on the functions of peripheral lymphoid organs and the liver. Injection of FasL⁺ LSA tumor cells into syngeneic C57BL/6 wild-type mice but not C57BL/6 lpr/lpr (Fas-deficient) mice caused apoptosis in splenocytes. Spleen cells expressing CD3, CD4, CD8, CD19, Mac-3, and CD44 were all susceptible to tumor-induced apoptosis. Also, activated T cells were more sensitive to apoptosis induced by LSA tumor cell lysate when compared to naïve T cells. In contrast, anti-Fas Abs (Jo2) induced apoptosis in only activated but not naïve T cells. When the LSA tumor-bearing mice were injected with a superantigen (SEA), these mice showed a significant decrease in the expansion of SEA-reactive Vβ3⁺ and Vβ11⁺ T cells. When injected into syngeneic mice, the FasL⁺ LSA tumor cells caused hepatotoxicity, as indicated by an increase in serum aspartate aminotransferase (AST) levels. Interestingly, Fas-deficient C57BL/6 lpr/lpr mice also showed significant AST levels in the serum following LSA tumor growth. Moreover, hepatocytes isolated from C57BL/6 wild-type and C57BL/6 lpr/lpr mice were equally susceptible to apoptosis induced by LSA tumor cell lysate in vitro. Using cDNA array, LSA tumor cells were found to express several cytokine genes including IL-2, IL-7, IL-11, IL-13, IL-16, lymphotoxin β, and tumor necrosis factor β. Together, these data suggested that, in mice bearing FasL⁺ LSA tumor, the immunotoxicity is FasL-based, whereas the hepatotoxicity, at least in part, may be FasL-independent.     

Effect of gossypol in association with chromium protoporphyrin on heme metabolic enzymes

Gossypol prevents the liberation of oxygen from oxyhemoglobin and exerts a hemolytic effect on erythrocytes. In excessive dosages of gossypol, an extreme burden is placed upon the respiratory and circulatory organs owing to the reduced oxygen carrying capacity of blood. Chromium protoporphyrin (CrPP) has been shown to either competitively suppress or to significantly ameliorate a variety of naturally occurring or experimentally induced forms of jaundice in animals and man. In this communication, a novel tissue dependent response to gossypol (50 micromol/kg bw) and gossypol in association with CrPP (50 micromol/kg bw) is described. Our results revealed that gossypol stimulated the hepatic, splenic, and renal delta-aminolevulinic acid synthase (ALA-S) activity, the heme biosynthetic enzyme, and simultaneous administration of CrPP and gossypol synergized the gossypol-mediated increase of ALA-S activity. Gossypol was found to be a potent stimulator of heme oxygenase (HMOX) activity in rat liver and kidney to varying degrees. This tissue response contrasted with that of the spleen, where gossypol decreased the activity of the enzyme. In consonance with the increased hepatic and renal HMOX activity, a marked increase was observed in total serum bilirubin concentration in gossypol treated rats. When rats were given CrPP simultaneously with gossypol, the gossypol mediated increase in hepatic and renal HMOX activity was effectively blocked. Furthermore, the increase in enzymatic activity was accomplished by a decline in the total microsomal protein content on gossypol administration. These findings emphasize the toxic effect of gossypol in eliciting increased heme degradation by stimulating HMOX activity in the liver and the kidney and the potential usefulness of CrPP in experimental and perhaps clinical conditions in which hyperbilirubinemia occurs.     

Adenosine deaminase in cord blood as an immunoenzyme marker in low birth weight neonates

Adenosine Deaminase (ADA) levels were estimated in cord blood of 30 neonates born with birth weight less than or equal to 2.5 kg and 30 neonates born with birth weight greater than 2.5 kg. The mean ADA levels in low birth weight (LBW) group was found to be 6.94 U/L and in normal birth weight group the mean ADA levels were 14.37 U/L which was statistically significant. Therefore ADA may be useful in assessing CMI status in low birth weight infants.     

Single radial immunodiffusion test for detecting antibodies against surface antigens of intracellular and extracellular vaccinia virus.

Antibodies to surface antigens of intracellular naked vaccinia virus (INV) and in limited studies extracellular enveloped virus (EEV) were determined by single radial immunodiffusion tests (SRDT) with immobilized virions in agarose gels. Antibodies to INV were demonstrable in rabbit hyperimmune sera (one to four visible zones), smallpox convalescent sera and sera from re-vaccinated individuals. A difference in specificity of antibodies reacting with INV and EEV was detectable by SRDT. The SRDT provides a simple, reproducible and specific test for detection of antibodies against vaccinia or variola virus, but the technique requires large quantities of virions.     

Molecular cloning and characterization of three beta-defensins from canine testes

Mammalian β-defensins are small cationic peptides possessing broad antimicrobial and physiological activities. Because dogs are particularly resilient to sexually transmitted diseases, it has been proposed that their antimicrobial peptide repertoire might provide insight into novel antimicrobial therapeutics and treatment regimens. To investigate this proposal, we cloned the full-length cDNA of three canine β-defensin isoforms (cBD-1, -2, and -3) from canine testicular tissues. Their predicted peptides share identical N-terminal 65-amino-acid residues, including the β-defensin consensus six-cysteine motif. The two longer isoforms, cBD-2 and -3, possess 4 and 34 additional amino acids, respectively, at the C terminus. To evaluate the antimicrobial activity of cBD, a 34-amino-acid peptide derived from the shared mature peptide region was synthesized. Canine β-defensin displayed broad antimicrobial activity against gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus; MICs of 6 and 100 μg/ml, respectively), gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Neisseria gonorrhoeae; MICs of 20 to 50, 20, and 50 μg/ml, respectively), and yeast (Candida albicans; MIC of 5 to 50 μg/ml) and lower activity against Ureaplasma urealyticum and U. canigenitalium (MIC of 200 μg/ml). Antimicrobial potency was significantly reduced at salt concentrations higher than 140 mM. All three canine β-defensins were highly expressed in testis. In situ hybridization indicated that cBD-1 was expressed primarily in Sertoli cells within the seminiferous tubules. In contrast, cBD-2 was located primarily within Leydig cells. The longest isoform, cBD-3, was detected in Sertoli cells and to a lesser extent in the interstitium. The tissue-specific expression and broad antimicrobial activity suggest that canine β-defensins play an important role in host defense and other physiological functions of the male reproductive system.     

Hydrophobically Modified Poly(acrylic acid) Using 3‐Pentadecylcyclohexylamine: Synthesis and Rheology

Summary: Hydrophobically modified poly(acrylic acid) was synthesized using 3‐pentadecylcyclohexylamine (3‐PDCA), which was in turn synthesized from 3‐pentadecylphenol, one of the components of cashew‐nut shell liquid (CNSL), a renewable resource material. ¹H NMR spectra confirmed the incorporation of 3‐PDCA onto PAA and a series of HMPs with three different molar concentrations, viz ? 3, 5 and 7 mol‐% of 3‐PDCA, were synthesized. An increase in viscosity with increasing hydrophobic content was observed by rheological measurements. The critical association concentrations were determined using an Ubbelohde viscometer and a controlled stress rheometer. The stability of HMPs towards temperature and shear was studied. Rheological measurements showed that there was a steady increase in viscosity with increase in hydrophobe content due to the formation of reversible networks. These polymers exhibited gel‐like behavior at low concentrations (≥2 wt.‐%) with an apparent yield stress (ca. 10 Pa) and showed shear thinning properties (non‐Newtonian). However, below a critical concentration, c [η], they showed Newtonian behavior.

η_sp of unmodified and modified PAA‐Na at various polymer concentrations.