Characterization of a toxin-deficient Clostridium perfringens strain, KZ1340

Clostridium perfringens KZ1340, previously classified as Clostridium plagarum, is an isolate from Antarctic soil, and was identified as an alpha-, theta-, and kappa-toxin non-producing variant. On Southern hybridization, the variant was found to be defective in the pfoA (theta-toxin) gene, but the plc (alpha-toxin) and colA (kappa-toxin) genes were present on the same EcoRI fragment as in the standard strain, NCTC8237. Northern analysis revealed that mature plc mRNA was transcribed in KZ1340 though less efficiently than in NCTC8237, while no mature colA mRNA was present in KZ1340. After transformation of the pfoA and plc genes into the KZ1340 via shuttle vector, pJIR418, the pfoA gene was successfully expressed but the plc gene was not efficiently expressed, suggesting that in KZ1340 there is negative regulation of plc gene expression. Toxin-deficient C. perfringens KZ1340 might be a suitable host for expression analysis of the pfoA gene and other clostridial virulence genes, if expressed efficiently, because it produces a small amount of extracellular toxins.

Tris(2,2'-bipyridyl)ruthenium(II)-mediated photoinduced electron transfer of engineered cytochrome P450 1A2

In this study, it is shown that an electron from photoreduced tris(2,2'-bipyridyl)Ru2+ ion reaches the haem iron of engineered wild-type cytochrome P450 1A2 (P450 1A2) with an electron transfer rate of 6.04 x 10(-3) min(-1). The electron transfer rate, 4.05 x 10(-2) min(-1), of a His163Glu mutant, which has a redox potential 40 mV lower than that of the wild type, is more than sixfold faster than that of the wild type. The photoinduced electron transfer rates of the present system are strongly influenced by detergents, cholic acid and Emulgen 913. We discuss the intermolecular and intramolecular electron transfer mechanism of the P450 1A2 system based on the kinetic data.

Selective increase of V beta 2+ T cells in the small intestinal mucosa in Kawasaki disease

The current study tested the hypothesis that the gastrointestinal tract could be one of the primary sites of entry for etiologic agents in Kawasaki disease (KD). In an attempt to elucidate the pathogenic role of certain superantigenic agents in KD, T cell receptor V beta expression by T cells in the small intestinal mucosa of KD patients was investigated using MAb on frozen tissue sections. Twelve Japanese patients with KD and eight controls were enrolled in the study. The numbers of cells stained by an immunofluorescence from each study group were counted and analyzed statistically by the t test. The occurrence of V beta 2+ T cells was found to be selectively increased in the small intestinal mucosa of patients in the acute phase of KD compared with controls (p < 0.01). In our previous study, five kinds of streptococci and two kinds of staphylococci, not detected in control patients, were isolated from the lumen of the jejunum of KD patients. These data suggest that the increased occurrence of V beta 2+ T cells in the jejunal mucosa of KD patients may be caused by exotoxins acting as superantigens produced by bacteria colonizing the small intestinal mucosa of these patients.

Tissue-specific response of the human platelet-activating factor receptor gene to retinoic acid and thyroid hormone by alternative promoter usage

We have studied the effects of retinoic acid (RA) and thyroid hormone (3,3',5-triiodothyronine; T3) on platelet-activating factor receptor (PAFR) gene expression in intact rats and the ability of two human PAFR gene promoters (PAFR promoters 1 and 2) to generate two transcripts (PAFR transcripts 1 and 2). Northern blotting showed that RA and T3 regulated PAFR gene expression only in rat tissues that express PAFR transcript 2. Functional analysis of the human PAFR promoter 2 revealed that responsiveness to RA and T3 was conferred through a 24-bp element [PAFR-hormone response element (HRE) located from -67 to -44 bp of the transcription start site, whereas PAFR promoter 1 did not respond to these hormones. The PAFR-HRE is composed of three direct repeated TGACCT-like hexamer motifs with 2-and 4-bp spaces, and the two upstream and two downstream motifs were identified as response elements for RA and T3. Thus, the PAF-PAFR pathway is regulated by the PAFR level altered by a tissue-specific response to RA and T3 through the PAFR-HRE of the PAFR promoter 2.

Platelet-activating factor receptor. Gene structure and tissue-specific regulation

The human platelet-activating factor receptor gene exists as a single copy on chromosome 1. Two 5'-noncoding exons (Exon 1 and 2) has distinct transcription initiation sites and promoters. These exons are alternatively spliced to a common splice acceptor site on exon 3 that contains a total coding regions. The transcript 1 is expressed ubiquitously with an emphasis of differentiated eosinophilic cell line (Eol-1), and leukocytes. On the other hand, the transcript 2 is expressed tissue-specifically. The latter is not expressed in leukocytes or brain. The transcript 1 has three tandem repeats of NF-kappa B, and SP-1 site, and responded to various inflammatory reagents including PAF itself, lipopolysaccharide, or phorbol ester. By northern blotting of tissue or cells with various nutritional or hormonal treatments, the PAF receptor messages are up-regulated. Estrogen increased the expression of the PAF receptor in human endometrial glandular cells, and vitamin A (retinoic acid) or thyroid hormone treatment up-regulates the PAF receptor expression only tissues with transcript 2 By various in vivo and in vitro transcriptional assays (CAT reporter assay, gel mobility shift assay), we identified estrogen responsible element, and hormone responsive element. The PAF receptor hormone responsive element is composed of three direct repeated TGACCT-like hexamer motifs with 2 and 4 bp spaces, and the two upstream and two downstream motifs were identified as response elements for RA and T.

[Complete remission of steroid-resistant minimal-change nephrotic syndrome by cyclosporin after additional low-density lipoprotein apheresis treatment]

Steroid-resistant nephrotic syndrome (SRNS) is still difficult to treat in spite of the introduction of various immunosuppressive drugs. In recent years, low-density lipoprotein apheresis (LDL-A) has been used to treat SRNS, mainly on focal glomerular sclerosis (FGS), and some cases have shown amelioration of the nephrotic syndrome. We describe here a case of steroid-resistant minimal-change nephrotic syndrome (MCNS), which was also unresponsive to cyclosporin A (CsA), but attained remission after the additional LDL-A treatment. A 20-year-old man with MCNS was treated with prednisolone at the dose of 40 mg/day for 6 weeks, but his nephrosis continued. The administration of CsA (2.5 mg/kg/day) induced remission temporarily for 2 months. However his nephrosis soon recurred, and persisted without improvement in spite of an increase in the CsA dose (4.5 mg/kg/day). After 6 LDL-A treatments given concomitantly with the administration of CsA (5 mg/kg/day), the urinary protein excretion remarkably reduced, and the patient remained free of the disease. Although the precise mechanism of hyperlipidemia on CsA is still unknown, it can be speculated that the rapid improvement of hyperlipidemia by LDL-A might strengthen the effect of CsA, presumably through the increased cellular uptake of CsA. LDL-A might be useful for ameliorating steroid-resistant MCNS, which also is unresponsive to immunosuppressive drugs, such as CsA.

Changes in head twitch response induced by a 5-hydroxytryptamine agonist in mice fed a low-protein diet

Long-term intake of a protein diet in infants causes the malnutrition syndrome known as kwashiorkor. Neurological symptoms in kwashiorkor have been reported occasionally. We studied the effects of malnutrition on murine behaviour by feeding growing mice a long-term low-protein diet. Three groups of 3-week-old male ddY mice were fed protein-controlled diets of 8,15 and 25% (control group) of total diet weight for 11 weeks immediately after weaning. The number of head twitches in 2 min were measured 2 min after injection of 10 mg/kg 5 -methoxy- N,N-dimethyltryptamine (5-MeODMT), a 5 -hydroxytryptamine (5 -HT) receptor agonist i.p. Organs were weighed after 10 weeks of feeding. Intracerebral monoamines and their metabolites were assayed using high performance liquid chromatography with electrochemical detection. Bodyweights of mice that were fed the 8% protein diet for 10 weeks were lower than in the other groups. The frequencies of the 5 -MeODMT-induced head twitch in mice that were fed the 8% low-protein diet for 4, 7 and 10 weeks were, respectively, 37.4, 21.4 and 45.2% those of the control group. The frequencies of head twitch also decreased in mice that were fed the 15% low-protein diet for 7 or 10 weeks. The locomotor activity of the mice was unchanged by the amount of protein in the diet. In assays of intracerebral monoamines, 5-HT and 5-HIAA in the whole brain and metabolic turnover of 5-HT increased significantly in mice that were fed the 8% low-protein diet for 11 weeks. Results suggest that head twitches in mice on long-term low-protein diets are suppressed due to the changes in the intracerebral serotonin system.

Role of insulin resistance associated with compensatory hyperinsulinemia in ischemic stroke

BACKGROUND AND PURPOSE

Although insulin resistance and hyperinsulinemia play a crucial role in the pathogenesis of atherosclerosis, little is known about their roles in ischemic stroke. The purpose of this study was to clarify whether insulin resistance and hyperinsulinemia are causative factors in the pathogenesis of ischemic stroke.

METHODS

Thirty-four consecutive patients with ischemic stroke, who were normotensive, nondiabetic, and not obese, were classified into three groups--atherothrombotic infarction (n = 16), lacunar infarction (n = 10), and cardioembolic infarction (n = 8)--based on clinical findings, brain imaging, and cerebral angiography. Both oral glucose tolerance tests and lipid analyses were performed. Insulin sensitivity was determined by the steady state plasma glucose method with the use of octreotide acetate. Data were compared with those of healthy control subjects (n = 15).

RESULTS

Steady state plasma glucose levels were significantly higher in the atherothrombotic infarction group compared with control subjects and the other two stroke groups, indicating the presence of insulin resistance in patients with atherothrombotic infarction. In the atherothrombotic infarction group, the 2-hour insulin area (area under the plasma insulin concentration curve) during a 75-g oral glucose tolerance test was significantly increased and dyslipidemic changes (increased triglyceride and apolipoprotein B, decreased high-density lipoprotein) were observed, whereas these changes were not found in the lacunar infarction and cardioembolic stroke groups.

CONCLUSIONS

Insulin resistance in association with compensatory hyperinsulinemia and dyslipidemia may be an important pathogenetic factor underlying the development of atherothrombotic infarction.

Immunoreactive analogues of erythrocyte ankyrin in human epidermal keratinocytes

Using immunoblot and immunofluorescence analysis, we demonstrated the presence and localization of an immunoreactive form of erythrocyte ankyrin in human epidermal keratinocytes. Immunoblot analysis revealed that both human epidermis and cultured epidermal keratinocytes contained ankyrin-like proteins of molecular mass 210 kDa that crossreacted with antihuman erythrocyte ankyrin antibodies. Immunofluorescence microscopy revealed that the plasma membrane of epidermal keratinocytes was stained. Eccrine sweat gland cells and ductal cells were also stained. These results indicate that in human epidermal keratinocytes, eccrine sweat gland cells and ductal cells, an ankyrin-like protein is present as one of the membrane proteins. The present findings and our recent previous studies showing the presence of a spectrin-like protein (fodrin) and 4.1-like proteins in these cells enable us to suggest that a membrane skeletal protein lattice may exist in these cells.

PAF-induced MAPK activation is inhibited by wortmannin in neutrophils and macrophages

In the present study we examined the mechanism by which PAF activates MAPK in native cells such as guinea-pig neutrophils and P388D1 macrophage-like cells. We found that PAF activates MAPK through two distinct pathways. One calcium-dependent pathway that likely involves cPKC, and another calcium-independent but wortmannin-sensitive pathway. Using molecular biological methods we are presently examining whether hetrodimeric (p85/p110) type PI 3-kinase is the actual target of wortmannin involved in PAF mediated activation of MAPK.

The beta-prism: a new folding motif

A new protein fold with internal symmetry has been observed in two proteins: vitelline membrane outer layer protein I (VMO-I) and delta-endotoxin. Despite lacking any discernible sequence similarity, both proteins have similar three-dimensional structures as well as a carbohydrate-binding site in the top region of the common fold.

[Pryce type I intralobar pulmonary sequestration]

A 53-year-old woman had a abnormal shadow in the left lower lung field on a chest radiograph, and occasional bloody sputum. CT scans and an MRI showed an abnormal vessel shadow between the aorta and the heart. An aortogram showed an abnormal artery originating from the descending aorta and entering the left lower lobe, and a pulmonary angiogram revealed no blood supply to the left basal segments. Pryce type I pulmonary sequestration was diagnosed. The patient underwent surgery, and the abnormal artery, 13 mm in diameter, was found to be connected from the descending aorta to the left lower lobe. The abnormal artery was dissected, and the left lower lobe was removed. The postoperative course was uneventful. We collected data on 24 cases of Pryce type I pulmonary sequestration reported in Japan. Such cases are comparatively rare and males are affected more often than females. The patient in the present case was the oldest woman to have undergone surgery for this condition in Japan. In patients who underwent surgery the greatest diameter of the abnormal artery was 18 mm.

Comparison of the biological activity of synthetic N-acylated asparagine or serine linked monosaccharide lipid A analogs

The mitogenicity, lethal toxicity, induction of tumor necrosis factor (TNF), production of nitric oxide (NO) and antitumor activity against Meth A fibrosarcoma by chemically synthesized N-acylated asparagine-linked (A-701, A-702 and A-703) or N-acylated serine-linked (A-607) nonphosphorylated acylglucosamine and 4-0-phosphorylated acylglucosamine (A-103) derived lipid A analogs were determined. compound A-607 (with tetradecanoyl and (R)-3-tetradecanoyloxytetradecanoyl at the C-2 and C-3 positions) induced a significant incorporation of 3H-thymidine into splenocytes of C3H/He mice at concentrations ranging from 3.13 to 50 microM, but the mitogenic activity of A-701 (2-N-acetylglucosamine), A-702 (tetradecanoyl at the C-2), and A-703 (with (R)-tetradecanoyloxytetradecanoyl and tetradecanoyl at the C-2 and C-3) was very weak. The lethality of A-703 and A-103 (with (R)-3-tetradecanoyloxytetradecanoyl at the C-2 and C-3) was weaker than that of A-607 at doses of 300 and 750 nmol/kg in C57BL/6 mice loaded with D-galactosamine. Peritoneal macrophages, stimulated with A-701-A-703, caused production of TNF which induce L929 cell lysis in vitro, and A-703 showed a high production of TNF. The compounds, except for A-607, exhibited little NO production by macrophages, but did induce the NO production in the presence of interferon gamma. Induction of TNF and NO inducible activity by A-703 was lower than that of A-607. A-703, A-607 and A-103 showed antitumor activity against Meth A fibrosarcoma in BALB/c mice. When A-703 or A-103 with muramyl dipeptide was administered, A-703 failed to show combined effects, but A-103 did. We concluded from these findings that the biological potency of asparagine compounds appears to be placed between serine- and amino-free compounds.

Dietary casein phosphopeptides prevent bone loss in aged ovariectomized rats

The effect of dietary Ca-bound casein phosphopeptides (CaCPP) on the bones of aged ovariectomized (OVX) rats was studied as a model for post-menopausal bone loss. Three groups of ovariectomized rats were fed a control diet or one of two experimental diets, and one group of sham-operated rats (SHAM) was fed the control diet. The experimental diets contained 0.5% Ca and 0.4% P. In one diet, CaCPP was the sole source of calcium and provided 62.5% of dietary phosphorus (CaCPP diet). In the other, Ca-free CPP provided 100% of dietary phosphorus (Ca-free CPP diet). In the control diet, CaCO3 and KH2PO4 were used. During a 17-wk feeding period, there was little change in femoral bone mineral densities (BMD) of ovariectomized rats fed CaCPP and Ca-free CPP, or in the SHAM rats fed the control diet, whereas the bone mineral densities in the control ovariectomized rats decreased with time. Some of the segmental bone mineral densities of the excised femurs from the rats fed CaCPP were significantly higher than those from the control ovariectomized rats, but the values of the Ca-free CPP group were similar to those of the control ovariectomized rats. In the Ca-free CPP group, the discrepancy in bone mineral densities obtained between in vivo results and excised specimens might have been the result of a loss in bone mass due to their significant loss in body weight. There were no significant differences in serum inorganic phosphorus, alkaline phosphatase activity, osteocalcin or 1 alpha-25-dihydroxycholecalciferol concentrations among the ovariectomized groups. In the CaCPP and Ca-free CPP groups, urinary phosphorus excretion decreased and urinary calcium excretion increased significantly with time. The inhibitory effect on bone loss in aged ovariectomized rats could be due to the effects of dietary CaCPP on phosphorus and calcium metabolism.

Re-evaluation of the probabilities for productive arrangements on the kappa and lambda loci

V-J arrangements at Ig light chain (IgL) genes occur in resting small pre-B cells. In the absence of cell division, the probability of production kappa and lambda rearrangements is proportional to the output of kappa+ B and lambda+ B cells in bone marrow. The kinetics and probability of productive kappa or lambda rearrangements was assessed in three groups of mice carrying two (wild-type), one or no intact Igkappa gene, and the following conclusion are drawn. Kappa and lambda rearrangements occur independently at different kinetics, and rearrangements are initiated at a time when kappa rearrangements are stopping. The probability of productive kappa and lambda rearrangements per chromosome is calculated to be approximately 60 and approximately 20% respectively. Thus, a kappa gene can attempt rearrangements up to three times per chromosome during B cell development. These findings explain that the observed ratio of kappa+ B/lambda+ B cell production in wild-type mice is 95/5.

Enhanced expression of platelet-activating factor receptor on human eosinophils by interleukin-3, interleukin-5 and granulocyte-macrophage colony-stimulating factor

The effects of interleukin-3 (IL-3), IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) on the surface expression of platelet-activating factor (PAF) receptor on eosinophils was examined using a PAF receptor binding assay. Specific binding of [3H]WEB 2086, a specific ligand for PAF receptor, to peripheral blood eosinophils obtained from healthy individuals was significantly increased when the cells were cultured with IL-3, IL-5, or GM-CSF for 12 h, compared with untreated cells. The PAF-induced increase in intracellular calcium ion concentration in eosinophils was markedly augmented by exposure to IL-5 for 12 h. These results suggest that these cytokines modulate the responsiveness of eosinophils to PAF through enhancement of PAF receptor expression on the cell surface.

Proliferation and teratogenicity of Aino virus in chick embryos

Aino virus (AIV; JaNAr 28 strain) 10(3) TCID50/0.2 ml was inoculated in the yolk sac of 8-day-old chick embryos. Recovery and titration of the virus from various organs including the central nervous system (CNS) and skeletal muscle were performed at 2, 4, 7, 10 and 13 days after inoculation (PI). AIV was systematically disseminated and proliferated even 2 days PI. The titers of the recovered virus from the CNS and from skeletal muscle was the highest at 4 days PI and declined with time, whereas hydranencephaly, arthrogryposis and cerebellar hypoplasia developed at 7 days PI and gradually progressed until 13 days PI.

[A case of superior vena cava syndrome treated with combination radiation and CRE (CBDCA and VP-16) therapy]

Carboplatin and etoposide were reported to be excellent radiation sensitizers. We encountered a patient with SVC syndrome due to lung cancer who was successfully treated by combination carboplatin, etoposide and hyperfractionation radiotherapy. A 72-year-old man was admitted to our hospital because of remarkable face edema. Computed tomography revealed a huge lung tumor and compressed SVC due to tumor growth. Acute tumor regression was essential for this case. We performed combination chemotherapy and radiation. The regime consisted of CBDCA 300 mg (day 1 1 hr drip infusion) and etoposide 50 mg/day for 21 days by oral administration. Two daily fractionations of 1.4 Gy were delivered 5 days-a-week, with a 4 h interval between fractions (total dose 49.8 Gy). Complete response of huge tumor was attained in this case. The major side effect associated with the therapy was myelosuppression. The patient's quality of life has been remarkably improved with this therapy.

Up-regulation of the intracellular Ca2+ signaling and mRNA expression of platelet-activating factor receptor by estradiol in human uterine endometrial cells

Platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine), a potent chemical mediator in inflammation, plays a role in reproduction. Using primary culture of human uterine endometrial cells, we investigated the effect of sex steroid hormones on the PAF-induced signal and its receptor mRNA expression. After a 24 hr treatment with estradiol, PAF increased the intracellular calcium ion ([Ca2+]i) in the glandular cells, but not in the stromal cells. This response was not observed in the non-treated cells, and was blocked by a PAF antagonist, WEB2086. Two types of mRNA (transcript 1 and transcript 2) occurred for PAF receptor by alternative splicing, which are under control of two distinct promoters. Using RT-PCR analysis, it was shown that both transcripts existed in endometrial cells and that estradiol alone or a combination of estradiol and progesterone induced the accumulation of transcript 2, the promoter of which responded to estrogen in our previous studies. The regulation of PAF receptor by sex steroid hormones in human uterine endometrial cells suggests that PAF is involved in the physiological process of reproduction.