Effects of dietary restriction on age-related immune dysfunction in the senescence accelerated mouse (SAM)

The effects of age and dietary restriction on immune response were investigated using an animal model of accelerated senescence (senescence accelerated mouse, SAM). The experimental groups consisted of control (ad libitum fed) and restricted groups (fed 60% of energy intake of the controls). Spleen weight and total number of splenic cells were significantly lower in the food-restricted group at 8 mo of age. Percentages of T (Thy-1.1+) and B (surface Ig+) cells in the splenic cells were not significantly different between the two groups. The number of direct hemolytic plaque-forming cells per 10(6) spleen cells 4 d following immunization with sheep red blood cells and dinitrophenyl-Ficoll was significantly greater in the 8-mo-old mice in the food-restricted group than in the control group. In the latter group, antibody responses Progressively decreased with age. Mitogen responses to concanavalin A and lipopolysaccharide were maintained in the food-restricted group but were depressed in the control group at 8 mo. In addition, though autoantibody to single-stranded DNA increased in the control group with advancing age, there was a steady decrease in the food-restricted group until 8 mo. Serum immunoglobulin (IgA and IgM) concentrations were significantly lower in the food-restricted group than in controls at 8 mo of age. Therefore, our results suggest that when senescence accelerated mice are subjected to food restriction, there may be a modulatory effect on the immune dysfunction associated with advancing age.     

Quantitative determination of N-glycolylneuraminic acid expression in human cancerous tissues and avian lymphoma cell lines as a tumor-associated sialic acid by gas chromatography-mass spectrometry

N-Glycolylneuraminic acid (NeuGc) is distributed in most animals except humans and chickens. However, human and chicken cancerous tissues often synthesize this heterophilic sialic acid as a tumor-associated Hanganutziu-Deicher antigen [M. Naiki and H. Higashi, Adv. Exp. Med. Biol., 152: 445-456, 1982; H. Higashi et al., Cancer Res., 45: 3796-3802, 1985]. In this paper, NeuGc in human cancerous tissues and chicken Marek's disease lymphoma cell lines was determined quantitatively with gas chromatography-mass spectrometry analysis using mass fragmentography. The detectable limit of NeuGc was 40 pg (0.12 pmol) in each injection using 5 ng of trideuteriomethyl ester trideuteriomethyl glycoside of the sialic acid as an internal standard sample when a pair of ions at m/e 386 and 389 was chosen for ion monitoring. NeuGc was detected in ganglioside-rich fractions of various human cancerous tissues from 5 of 8 patients examined but was not detected in glycosphingolipids of normal human tissues. The contents of NeuGc in these cancerous tissues ranged from 0.02 to 0.5% of the total sialic acid content. NeuGc was also detected in freeze-dried samples of 5 different cell lines from chicken Marek's disease lymphomas but was not detected in a cell line from chicken lymphoid leukosis lymphoma and normal chicken skeletal muscle tissue. The contents of NeuGc in the positive cell lines ranged from 0.03 to 0.11% of the total sialic acid content. These results indicate that NeuGc can be synthesized in both humans and chickens in some cancers.     

The inclusion of an omental flap in pancreatoduodenectomy

A technique for reducing the morbidity and mortality of pancreatoduodenectomy by using an omental flap to protect the anastomoses and splanchnic vessels exposed during dissection is described herein.     

Metabolism of senile amyloid precursor and amyloidogenesis. Age-related acceleration of apolipoprotein A-II clearance in the senescence accelerated mouse.

Serum clearance kinetics of murine senile amyloid-related high-density lipoprotein (HDL) apoprotein A-II (apo A-II) was examined in the senescence-accelerated mouse, prone (SAM-P/1) and resistant (SAM-R/1), with 125I-HDL purified from both strains. In SAM-R/1, with 125I-HDL purified from both strains. In SAM-R/1, the serum half-life of apo A-II was not altered with increasing age and was practically identical to that of apo A-I. In 2-month old SAM-P/1, the serum half-life of both apo A-I and apo A-II was generally the same as observed in SAM-R/1. However, at age 6 and 12 months, in SAM-P/1, the serum half-life of apo A-II decreased significantly and was less than that of apo A-I. These age-related changes in apo A-II clearance kinetics were observed regardless of the HDL donor. The authors also examined the tissue distribution of injected apo A-II, using 125I-apo A-II reconstituted HDL, and found that several organs trapped more 125I radioactivity in old SAM-P/1 than in young mice. This evidence strongly suggests that age-related changes in the metabolic environment of apo A-II might affect senile amyloidogenesis in SAM-P/1.     

Possible role of hepatocyte growth factor in regeneration of human peritoneal mesothelial cells

Human peritoneal mesothelial cells (HPMCs) play an important role in peritoneal functions. During long term peritoneal dialysis, it has been reported that HPMCs are damaged by high glucose solution via the signal of transforming growth factor (TGF)-beta1 produced by HPMCs. In this study, we focused on the effect of hepatocyte growth factor (HGF), known as an anti-fibrotic and anti-TGF-beta1 agent, on HPMCs damaged by high glucose solution. HPMCs were isolated from specimens of the omentum from nonuremic patients after informed consent had been obtained. After confirming adhesion for 6 hours, 100 microL of DMEM with 0.5%FCS were added at different concentrations (D-glucose; 6, 30 mM) with or without HGF (10, 30, 100 ng/mL) for 48 hours. We examined the effects of a high concentration of glucose and then focused on following four critical points: 1) the production of HGF from HPMCs exposed to a high concentration of glucose, 2) the expression of c-Met on HPMCs, 3) the viability of those cells, and 4) matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinase-2 (TIMP-2). The following significant changes are described herein: high glucose solution and TGF-beta1 i) decreased HGF production from HPMCs and ii) up-regulated expression of c-Met on HPMCs, and addition of HGF iii) restored viability of HPMCs damaged by glucose, iv) suppressed TGF-beta1 production by HGF, and v) induced up-regulation of MMP-2 and decreased TIMP-2 production by HPMCs. Levels of HGF decreased by high concentrations of glucose in the peritoneal cavity may induce the loss of HPMCs and thereby result in peritoneal fibrosis. These results suggest that HGF is an effective agent in the regeneration of peritoneal membrane damaged by high glucose solution.     

Kinetic analysis of amyloid fibril polymerization in vitro

We investigated the polymerization kinetics of murine senile amyloid fibrils (fASSAM) in vitro. When sonicated murine senile amyloid fibrils was incubated with its constituent monomer protein, the extension of amyloid fibrils was observed in an electron microscopic analysis. Quantitative fluorometric analysis with thioflavine T (Naiki H, Higuchi K, Hosokawa M, Takeda T: Anal Biochem 177:244, 1989) revealed that (a) extension of amyloid fibrils occurred by a pseudo-first-order exponential increase in the fluorescence of thioflavine T; (b) the rate of extension was maximal around pH 7.5, and was inhibited with the increase in KCl or NaCl concentration in the reaction mixture; (c) the rate of polymerization was proportional to the product of the murine senile amyloid fibrils number concentration and the constituent monomer protein concentration; (d) the net rate of extension was the sum of the rates of polymerization and depolymerization with the equilibrium association constant K of 5 x 10(7) M-1. These results show that amyloid fibril formation can apparently be explained by a first-order kinetic model: that is, extension of amyloid fibrils proceeds by consecutive association of precursor proteins onto the ends of existing fibrils.     

HBME‐1 and CD15 immunocytochemistry in the follicular variant of thyroid papillary carcinoma

Papillary carcinoma is the most common thyroid malignancy. As the cytological diagnosis of papillary carcinoma is not difficult in patients with the usual type of lesion, fine‐needle aspiration (FNA) cytology is an effective method for preoperative evaluation. However, this modality is often ineffective in identifying the follicular variant of papillary thyroid carcinoma (FVPTC) due to its similarity to other follicular lesions and the incompleteness of typical nuclear features. Therefore, we investigated the expression of immunocytochemical markers of papillary carcinoma in cytological specimens of FVPTC and evaluated their utilities. The immunoreactivity of HBME‐1 and CD15 was investigated using 50 imprint smear cytological specimens obtained from thyroid lesions, including 13 FVPTC. The sensitivity and specificity of HBME‐1 for FVPTC were 92% and 89%, respectively, while those of CD15 were 23% and 100%, respectively. In conclusion, HBME‐1 is a sensitive marker of papillary carcinoma, including both usual type and FVPTC, in cytological specimens. Therefore, using HBME‐1 immunocytochemistry in FNA cytology will lead to reduction of the incidence of false‐negative diagnoses of FVPTC. Although CD15 is apparently inferior in terms of sensitivity for FVPTC, its excellent specificity will support the definitive diagnosis of thyroid malignancies, including FVPTC, after screening with HBME‐1.     

Cytochrome P450 oxidoreductase gene mutations and Antley-Bixler syndrome with abnormal genitalia and/or impaired steroidogenesis: molecular and clinical studies in 10 patients

We report on molecular and clinical findings in 10 Japanese patients (four males and six females) from eight families (two pairs of siblings and six isolated cases) with Antley-Bixler syndrome accompanied by abnormal genitalia and/or impaired steroidogenesis. Direct sequencing was performed for all the 15 exons of cytochrome P450 oxidoreductase gene (POR), showing two missense mutations (R457H and Y578C), a 24-bp deletion mutation resulting in loss of nine amino acids and creation of one amino acid (L612_W620delinsR), a single bp insertion mutation leading to frameshift (I444fsX449), and a silent mutation (G5G). R457H has previously been shown to be a pathologic mutation, and computerized modeling analyses indicated that the 15A>G for G5G could disturb an exonic splicing enhancer motif, and the remaining three mutations should affect protein conformations. Six patients were compound heterozygotes, and three patients were R457H homozygotes; no mutation was identified on one allele of the remaining one patient. Clinical findings included various degrees of skeletal features, such as brachycephaly, radiohumeral synostosis, and digital joint contractures in patients of both sexes, normal-to-poor masculinization during fetal and pubertal periods in male patients, virilization during fetal life and poor pubertal development without worsening of virilization in female patients, and relatively large height gain and delayed bone age from the pubertal period in patients of both sexes, together with maternal virilization during pregnancy. Blood cholesterol was grossly normal, and endocrine studies revealed defective CYP17A1 and CYP21A2 activities. The results suggest that Antley-Bixler syndrome with abnormal genitalia and/or impaired steroidogenesis is caused by POR mutations, and that clinical features are variable and primarily explained by impaired activities of POR-dependent CYP51A1, CYP17A1, CYP21A2, and CYP19A1.