Transfer of human serum IgG to nonobese diabetic Igmu null mice reveals a role for autoantibodies in the loss of secretory function of exocrine tissues in Sj?gren's syndrome

The NOD (nonobese diabetic) mouse has been studied as an animal model for autoimmune insulin-dependent diabetes and Sj?gren's syndrome. NOD.Igmu null mice, which lack functional B lymphocytes, develop progressive histopathologic lesions of the submandibular and lachrymal glands similar to NOD mice, but in the absence of autoimmune insulitis and diabetes. Despite the focal appearance of T cells in salivary and lachrymal tissues, NOD.Igmu null mice fail to lose secretory function as determined by stimulation of the muscarinic/cholinergic receptor by the agonist pilocarpine, suggesting a role for B cell autoantibodies in mediating exocrine dryness. Infusion of purified serum IgG or F(ab')2 fragments from parental NOD mice or human primary Sj?gren's syndrome patients, but not serum IgG from healthy controls, alters stimulated saliva production, an observation consistent with antibody binding to neural receptors. Furthermore, human patient IgG fractions competitively inhibited the binding of the muscarinic receptor agonist, [3H]quinuclidinyl benzilate, to salivary gland membranes. This autoantibody activity is lost after preadsorption with intact salivary cells. These findings indicate that autoantibodies play an important part in the functional impairment of secretory processes seen in connection with the autoimmune exocrinopathy of Sj?gren's syndrome.     

Brainstem application of melanocortin receptor ligands produces long-lasting effects on feeding and body weight

Recent evidence suggests that the central melanocortin (MC) system is a prominent contributor to food intake and body weight control. MC receptor (MC-R) populations in the arcuate and paraventricular nuclei are considered probable sites of action mediating the orexigenic effects of systemically or intracerebroventricularly administered ligands. Yet, the highest MC4-R density in the brain is found in the dorsal motor nucleus of the vagus nerve, situated subjacent to the commissural nucleus of the solitary tract, a site of pro-opiomelanocortin mRNA expression. We evaluated the contribution of the caudal brainstem MC system by (1) performing respective dose-response analyses for an MC-R agonist (MTII) and antagonist (SHU9119) delivered to the fourth ventricle, (2) comparing, in the same rats, the fourth intracerebroventricular dose-response profiles to those obtained with lateral intracerebroventricular delivery, and (3) delivering an effective dose of MTII or SHU9119 to rats before a 24 hr period of food deprivation. Fourth intracerebroventricular agonist treatment yielded a dose-dependent reduction of short-term (2 and 4 hr) and longer-term (24 hr) food intake and body weight. Fourth intracerebroventricular antagonist treatment produced the opposite pattern of results: dose-related increases in food intake and corresponding increases in body weight change for the 24-96 hr observation period. Comparable dose-response functions for food intake and body weight were observed when these compounds were delivered to the lateral ventricle. Results from deprived rats (no effect of MTII or SHU9119 on weight loss) support the impression derived from the dose-response analyses that the body weight change that follows MC treatments is secondary to their respective effects on food intake. Results support the relevance of the brainstem MC-R complement to the control of feeding.     

Imaging of incidentally discovered adrenal masses

Fucosyltransferases (FTs) and various glycosidases that are involved in the biosynthesis or degradation of SSEA-1 (Le(x)) antigens and their precursors in the CNS are developmentally regulated. In forebrain and cerebellum with lactosamine (LacNAc) as acceptor the FT activity was maximal at P15-P22, but with the glycolipid substrate paragloboside (nLc4) the maximal activity in cerebellum was obtained at P10-P15. The FT activity, with these substrates, was insensitive to N-ethylmaleimide (NEM) and the glycolipid product had an alpha1,3 linkage (Fuc to GlcNAc) suggesting similarities of the investigated enzyme to the cloned human and rat FT IV. However, the observation of different patterns of FT activity in isoelectrofocused fractions (pH 3.5-10) with different types of acceptors, and the differential expression of Le(x) containing glycolipids and glycoproteins during development strongly suggest the presence of more than one type of FT during development. Data on developmental expression of the hydrolytic enzymes, alpha-L-fucosidase, beta-D-galactosidase and alpha-D-galactosidase, which can potentially hydrolyse SSEA-1 or its precursors, support the notion that SSEA-1 expression is the result of a dynamic balance between the activity of transferases and hydrolases.     

Promyelocytic blast crisis of chronic myelogenous leukaemia with translocations (9;22) and (15;17)

The murine monoclonal antibody A7 (MAb A7) is reactive against most human gastric cancer cell lines. Using a nude mouse peritoneal dissemination model of human gastric cancer, we investigated targeted chemotherapy using a conjugate of neocarzinostatin (NCS) with MAb A7 (A7-NCS). After demonstrating cytotoxicity of the complex against the human gastric cancer cell line MKN45 in vitro, we intraperitoneally injected A7-NCS, NCS or saline into nude mice bearing peritoneally disseminated human gastric cancer. A7-NCS inhibited peritoneal dissemination significantly more effectively than NCS. MAb A7 may prove to be an effective carrier for antineoplastic drugs in patients with peritoneal dissemination of gastric cancer.     

Evaluation of residual stress in rabbit skin and the relevant material constants

BACKGROUND: The finding of characteristic small intestinal mucosal abnormalities on histologic examination of a biopsy specimen remains the first requirement for the diagnosis of celiac disease. A reliable and noninvasive test would be ideal for the patient's convenience and for reducing health-care costs. The sensitivity and specificity of anti-gliadin antibodies (AGA-immunoglobulin [Ig] G, AGA-IgA) have been variable; anti-endomysium IgA (EmA-IgA) is more helpful. In an earlier study conducted at the authors' institution, celiac disease was present in 19 patients examined from 1992 to 1995. Anti-endomysium titers were higher than normal in all 19 patients (100%). Total villous atrophy was seen in 14 of 17 biopsy specimens (82%) and subtotal atrophy in 3 (18%). The purpose of the current study was to evaluate further the accuracy of EmA-IgA in diagnosing celiac disease. METHODS: One hundred seven patients were screened for celiac disease between March 1996 and July 1997. The level of EmA-IgA was measured in all patients, and AGA-IgG and AGA-IgA were measured in 104 patients. Forty-six patients underwent endoscopic biopsy of the small bowel, with measurement of disaccharidase enzymes in 45 patients. RESULTS: Five of 46 patients had celiac disease (three boys and two girls; mean age, 5.3 years; 2-9.5 years); one also had cystic fibrosis and another had insulin-dependent diabetes mellitus. All five had marked to complete villous atrophy with crypt hyperplasia and increased serum EmA-IgA (100% sensitivity). None of the remaining patients had increased EmA-IgA (100% specificity). Serum levels of AGA-IgG and AGA-IgA were increased in all four celiac disease patients (100% sensitivity), but they were also high in patients without celiac disease (38% and 92% specificity, respectively), which compromises their diagnostic value. None of the patients confirmed to have celiac disease had IgA deficiency. Abnormal disaccharidase enzyme activities were documented in all five celiac disease patients: severe generalized deficiency (n = 2), moderately severe generalized deficiency (n = 2), and alactasia with moderate deficiency of the alpha-glucosidases (n = 1). CONCLUSIONS: This study confirmed the reliability and accuracy of EmA-IgA in the diagnosis of celiac disease. Small bowel biopsy may be unnecessary in EmA-positive patients in whom celiac disease is suspected.     

Comparative pharmacodynamics of CYP2B induction by DDT, DDE, and DDD in male rat liver and cultured rat hepatocytes

In this study the pharmacodynamics were characterized of rat hepatic cytochrome P-450 2B (CYP2B) induction by the pesticide DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], which is bioretained, and DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane], which is metabolized further and therefore less prone to bioaccumulate. DDT, DDE, and DDD were each found to be pure phenobarbital-type cytochrome P-450 inducers in the male F344/NCr rat, causing induction of hepatic CYP2B and CYP3A, but not CYP1A. The ED50 values for CYP2B induction (benzyloxyresorufin O-dealkylation) by DDT, DDE, and DDD were, respectively, 103, 88, and > or = 620 ppm in diet (14 d of exposure). The efficacies (Emax values) for induction of benzyloxyresorufin O-dealkylation by DDT, DDE, and DDD were 24-, 22-, and > or = 1-fold, respectively, compared to control values. The potencies of the three congeners for CYP2B induction appeared also to be similar, with EC50 values (based on total serum DDT equivalents) of 1.5, 1.8, and > or = 0.51 microM, respectively. The EC50 values based on DDT equivalents in hepatic tissue were 15, 16, and > or = 5.9 micromol/kg liver tissue, respectively. In primary cultures of adult rat hepatocytes, DDT, DDE, and DDD each displayed ability to induce total cellular RNA coding for CYP2B (ED50 values of 0.98, 0.83, and > or = 2.7 microM, respectively). These results suggest that DDT, DDE, and DDD each possess a high degree of intrinsic CYP2B-inducing ability for rat liver, despite marked differences in bioretention among the congeners.     

The role of transforming growth factor-beta1, -beta2, and -beta3 in androgen-responsive growth of NRP-152 rat prostatic epithelial cells

Proacrosin, the zymogen form of the serine protease beta-acrosin, is thought to function as a secondary binding molecule between mammalian gametes during fertilization (Jansen et al., 1995: Int J Dev Biol 39, 501-510). The interaction involves strong ionic bonds between positively charged amino acids on proacrosin and negatively charged polysulphate groups on zona pellucida glycoproteins. In this investigation, we identified the basic residues on proacrosin that are important for this binding. Site-directed mutagenesis shows that two groups of amino acids comprising His47, Arg50, and Arg51 together with Arg250, Lys252, and Arg253 are crucial because their deletion or replacement severely reduces affinity for zona glycoproteins. Molecular models of proacrosin reveal that these residues are located along one face of the protein on two exposed surface loops that project over and around the catalytic site. These findings support the hypothesis that polysulphate binding sites on proacrosin are formed by a restricted number of basic amino acids on the surface of the protein, presenting a specific orientation that is complementary to negatively charged sulphate groups on zona glycoproteins. Identification and elucidation of the stereochemistry of these charged moieties will aid design of new kinds of nonsteroidal antifertility agents.