Synthesis and properties of molecularly uniform oligourethanes with chain-folding units in the center

The study of a series of molecularly uniform poly(N-alkylurethanes) with a systematically varied and tailored chain architecture has shown that the packing and superstructure can be controlled by the primary structure of the urethane chain and reversibly altered by the sample treatment, respectively. Depending on the conformation or the stereogeometry of the constitutive unit built in the middle of the otherwise symmetrical oligourethane, chain-extended and/or chain-folded crystallization of the urethane chain can occur. The packing order, i. e., adjacent recentry chain-folding or chain-extended crystallization, and the thermal properties of the oligourethanes are related to the chemical structure of the central constitutive unit.     

Spontaneous reanastomosis between lymphatic vessels following syngeneic transplantation of the small intestine in the rat

Abstract Spontaneous lymphvascular reanastomosis (SLR) following small bowel transplantation in rats is of clinical relevance for the resorption of long chain fatty acids. Detailed morphological and molecular data concerning the process of lymphvascular reanastomosis are not available in the literature. In this study SLR was investigated using microradiology and scanning electron microscopy. Between the 8^th and 21^st postoperative days following transplantation SLR does not occur between the intestinal trunk of the transplant and the thoracic duct of the recipient. Instead, an indirect connection was observed between the inserted advential lymphatic vessels of the mesenteric artery and lymphatic vessels of the aorta or ductus deferens, which are connected with the thoracic duct.     

Application of Scanning Acoustic Microscopy for Assessing Stress Distribution in Atherosclerotic Plaque

Scanning acoustic microscopy (SAM) was equipped to assess the acoustic properties of normal and atherosclerotic coronary arteries. The SAM image in the atherosclerotic lesion clearly demonstrated that the sound speed was higher than that in the normal intima, and that the variation of elasticity was found within the fibrous cap of the plaque. Young's elastic modulus of each region was calculated and the finite element analysis was applied to derive the stress distribution in these arterial walls. In a case of normal coronary artery, the stress was dominant in the intima and the distribution was rather homogeneous and in a case of atherosclerosis, high stress was concentrated to the relatively soft lesion in the fibrous cap overlying lipid pool. SAM provides information on the physical properties, which cannot be obtained by the optical microscope. The results would help in understanding the pathological features of atherosclerosis. © 2001 Biomedical Engineering Society. PAC01: 8764-t, 8763Df, 8719Xx, 8719Rr     

Neuropsychological functions,sleep, and mental health in adults with Klinefelter syndrome

A few studies have examined neuropsychological functions, sleep, and mental health combined in Klinefelter syndrome (KS; 47,XXY). We investigated neuropsychological functions with standard tests, sleep with actigraphy, and self‐reported mental health in 30 men with KS (Mean age = 36.7 years) compared to 21 controls (Mean age = 36.8 years). Men with KS scored significantly lower on mental speed, attention span, working memory, inhibition, and set‐shifting tests, as well as overall IQ (mean effect size difference Cohen's d = 0.79). Men with KS had significantly longer night wakes, with no differences in other sleep variables (mean d = 0.34). Men with KS reported poorer mental health than controls (mean d = 1.16). Regression analyses showed neuropsychological functions explained variance in some sleep domains for men with KS but not for controls. Neuropsychological functions explained variance in some mental health domains for controls. For men with KS, however, verbal IQ was the only significant predictor of mental health. Altogether, men with KS display problems in neuropsychological functions and mental health but do not appear different from controls on most sleep parameters. Our findings indicate that relations between neuropsychological functions, sleep, and mental health differ between men with KS and controls.     

New recombinants within the MHC (B-complex) of the chicken

In a search for genetic recombinations within the major histocompatibility complex (MHC) of the chicken, the B-complex, the offspring from matings between heterozygous B15/B21 and B4/B6 animals were analysed by red cell agglutination. Among the progeny, 8,912 informative typings were performed. Four recombinants were found, all separating the B-complex loci B-F and B-G (B-F codes for Class I antigens, B-G codes for an antigen of which there is no known homologue in mammals). B-L (Class II antigen) always followed B-F. Stimulation in graft versus host reactions and in mixed lymphocyte cultures followed B-F/B-L. The mapping distance between the two loci B-F and B-G is in the range of 0.04 centimorgan. The lack of recombinants separating individual B-F loci in this study and in the studies of others might indicate that chicken MHC is less complex than those of mammalian species, but alternative explanations are also possible. So far no serologically defined recombinant separating Class I (B-F) and Class II (B-L) loci has been found.     

Expression and synthesis of fibroblast growth factor-9 in human gammadelta T-lymphocytes. Response to isopentenyl pyrophosphate and TGF-beta1/IL-15

Gammadelta T-lymphocytes are believed to play a role in maintaining the normal configuration of epithelial tissue. As little is known about the factors mediating this function, we addressed the question of whether gammadelta T-lymphocytes produce fibroblast growth factor (FGF)-9 as well as two other growth factors associated with epithelial tissue reconstitution. Blood gammadelta T cells isolated from healthy donors were grown in the presence of isopentenyl pyrophosphate (IPP) or transforming growth factor-beta1 (TGF-beta1)/interleukin-15 (IL-15) for 24 h and were assessed for the expression and synthesis of FGF-9, keratinocyte growth factor (KGF), and epidermal growth factor (EGF). Resting human gammadelta T cells constitutively expressed KGF and FGF-9 mRNA but no EGF mRNA. In the presence of IPP, FGF-9 mRNA expression significantly increased in a dose-dependent manner, expression of KGF remained unaltered, and EGF mRNA could not be detected. In contrast to IPP, stimulation of the cells with TGF-beta1/IL-15 did not alter FGF-9 expression. Moreover, stimulation with anti-CD3 does not induce FGF-9 expression but triggers a high signal of interferon-gamma mRNA. Western blot analysis of gammadelta T cell lysates, prepared 4 days following stimulation with IPP, showed an increase of FGF-9 protein as compared with control cells. In conclusion, the results demonstrate for the first time that human blood and bronchoalveolar lavage gammadelta T-lymphocytes are capable of expressing FGF-9. The data also provide novel evidence that immunoregulatory cells can synthesize FGF-9.     

Fas and Fas-ligand are expressed in the uteroplacental unit of first-trimester pregnancy

PROBLEM: Fas and Fas-ligand (FasL) are thought to provide a strategy for reducing graft rejection in immunologically 'privileged' tissues by controlling injurious lymphocyte reactions. As the uteroplacental unit is often defined as an immune-privileged site, we investigated the expression of Fas and FasL in this tissue in the first trimester of pregnancy. METHOD OF STUDY: Western blotting, immunohistochemistry, and double immunofluorescence were used for this examination. RESULTS: Western blotting with purified first-trimester trophoblast cells revealed one specific band for FasL. The presence of FasL on different trophoblast populations could be confirmed by immunohistochemistry and double immunofluorescence. In the villous part of the placenta, FasL is mostly located on cytotrophoblast cells with no access to maternal blood flow, whereas in trophoblast-invaded uterine tissue, interstitial trophoblast cells, which are in close contact with maternal leukocytes, revealed a strong signal for FasL, but no staining for Fas on these cells. However, Fas was found on CD45+ maternal leukocytes. CONCLUSION: Based on our experimental findings, we speculate that the abundant presence of FasL on trophoblast cells within the maternal decidua may play an important role in the maintenance of immune privilege in the pregnant uterus by endowing fetal trophoblast cells with a defense mechanism against activated maternal leukocytes, whereas in the villous part of the placenta, the Fas FasL system seems to be involved in the regulation of placental growth.