A murine platelet-activating factor receptor gene: cloning, chromosomal localization and up-regulation of expression by lipopolysaccharide in peritoneal resident macrophages

A murine gene encoding a platelet-activating factor receptor (PAFR) was cloned. The gene was mapped to a region of the D2.2 band of chromosome 4 both by fluorescence in situ hybridization and by molecular linkage analysis. Northern blot analysis showed a high expression of the PAFR message in peritoneal macrophages. When C3H/HeN macrophages were treated with bacterial lipopolysaccharide (LPS) or synthetic lipid A, the PAFR gene expression was induced. Bacterial LPS, but not lipid A, induced the level of PAFR mRNA in LPS unresponsive C3H/HeJ macrophages. These induction patterns were parallel to those of tumor necrosis factor-alpha mRNA. Thus the PAFR in macrophages is important in LPS-induced pathologies.

[Abnormal head drooping in facioscapulohumeral muscular dystrophy]

Diagnosis of facioscapulohumeral muscular dystrophy (FSHD) is based on its characteristic pattern of muscle wasting. Initial symptom is usually shoulder girdle and upper arm muscle wasting resulting in difficulty in arm-lifting. Patients are aware of progressive change of facial appearance caused by characteristic facial muscle weakness. Affection of other muscles is usually realized much later, but, there is a considerable variation in pattern and severity between individuals even in the same family so that several clinical subtypes such as jump form or scapuloperoneal syndrome have been proposed. Here we described three patients with FSHD showing conspicuous head-drooping caused by severe wasting of posterior neck muscles. These patients realized abnormal neck posture much earlier than appearance of obvious gait disability, while they show other characteristic FSHD features. Familial occurrence is observed in two cases, other affected members from both families do not show abnormal head drooping. Therefore we regarded this sign as another example of clinical heterogeneity of this genetic disorder.

Absence of a mutation of the p21/WAF1 gene in human lung and pancreatic cancers

The expression of a negative regulator of the cell cycle, p21WAF1 protein, is trans-activated by wild-type p53, but not by the mutant protein. Therefore, mutations of the p53 and WAF1 genes may be complementary. We examined DNAs from 70 human primary lung (63 of NSCLC and 7 of SCLC) and 24 pancreatic cancers (19 primary cancers and 5 cell lines) for mutations of the WAF1 gene. No mutations were detected in any samples examined, regardless of the mutational state of the p53 gene. The results suggested that aberrations of the coding sequence of the WAF1 gene are not associated with carcinogenesis in lung and pancreatic cancers.

Relationship between the acid-induced cough response and airway responsiveness and obstruction in children with asthma

BACKGROUND

In children with asthma little is known about the direct effect of the bronchoconstrictor and bronchodilator response on the cough threshold, or the relationship between bronchial responsiveness and the cough threshold. A study was undertaken to determine the effect of histamine-induced bronchoconstriction and salbutamol-induced bronchodilatation on the cough threshold in response to inhaled acetic acid, and to examine the relationship between the acetic acid cough threshold and bronchial hyperresponsiveness to histamine in children with asthma.

METHODS

Nineteen children with asthma (16 boys) of mean (SE) age 10.6 (0.6) years were enrolled in the study. On day 1 each underwent a histamine inhalation challenge to determine the provocative concentration causing a fall in forced expiratory volume in one second (FEV1) of more than 20% (PC20) as an index of individual bronchial hyperresponsiveness. On day 2 the acetic acid cough threshold was determined before and just after the inhalation of the PC20 concentration of histamine, and then salbutamol (1 mg/m2) was inhaled to relieve the bronchoconstriction. Ten of the 19 patients (eight boys) of mean age 12.2 (0.7) years also tried acetic acid inhalation challenge just after salbutamol inhalation.

RESULTS

There was no relationship between the bronchial responsiveness to histamine and acetic acid cough threshold in these patients. The acetic acid cough threshold after histamine inhalation was similar to that before histamine, although FEV1 decreased after histamine. In the 10 patients who also tried acetic acid inhalation challenge after salbutamol the cough threshold did not change.

CONCLUSIONS

These findings suggest that acid-induced cough sensitivity and bronchomotor tone are independently regulated in children with asthma.

Non-viral sequences at the 5' termini of mRNAs derived from virus-sense and virus-complementary sequences of the ambisense RNA segments of rice stripe tenuivirus

The three small segments of the four RNAs of the rice stripe tenuivirus (RSV) genome have an ambisense coding strategy. The mRNA transcripts corresponding to open reading frames for the non-structural protein (NS4) and nucleocapsid protein (N), which are encoded on virus-sense (v) RNA 4 and virus-complementary sense (vc) RNA 3, respectively, were recovered from polysomes of RSV-infected wheat leaves, and their 5' termini were analysed. The mRNAs derived from both v and vc sequences contained from 10 to 23 non-viral bases at their 5' termini. Results of nucleotide sequence similarity analyses indicated that these non-viral heterogeneous sequences may be derived from host cellular mRNAs. Taken together, these results suggest that the viral mRNA transcription of either v or vc sequences of ambisense segments of RSV is primed by non-viral oligonucleotides in vivo.

Superoxide anion reduces the ability of myeloperoxidase to damage lipids

The aim of this study was to determine whether lipids are damaged by myeloperoxidase (MP) not only with hydrogen peroxide (H2O2), but also with a H2O2-generating system. Using the hypoxanthine-xanthine oxidase-Cu,Zn-superoxide dismutase (HX-XO-SOD) system as an effective H2O2-generating system, we observed a reduction in the ability of MP to produce peroxylipids in the HX-XO-SOD-MP system, compared with the H2O2-MP system. We also noted that MP inhibited the production of monoepoxide by the H2O2-cytochrome c (Cyt c) system. These results suggest that MP plays a role as an absorber of active oxygen species and prevents phagocytes from self-destruction.

cDNA cloning, expression, and mutagenesis study of leukotriene B4 12-hydroxydehydrogenase

Leukotriene B4 12-hydroxydehydrogenase catalyzes the conversion of leukotriene B4 into its biologically less active metabolite, 12-oxo-leukotriene B4. This is an initial and key step of metabolic inactivation of leukotriene B4 in various tissues other than leukocytes. Here we report the cDNA cloning for porcine and human enzymes from kidney cDNA libraries. A full-length cDNA of the porcine enzyme contains an open reading frame consisting of 987 base pairs, corresponding to 329 amino acids. The human enzyme showed a 97.1% homology with the porcine enzyme. Northern blotting of human tissues revealed its high expression in the kidney, liver, and intestine but not in leukocytes. The porcine enzyme was expressed as a glutathione S-transferase fusion protein in Escherichia coli, which exhibited similar characteristics with the native enzyme. Because the enzymes have a homology, in part, with NAD(P)(+)-dependent alcohol dehydrogenases, a site-directed mutagenesis study was carried out. We found that three glycines at 152, 155, and 166 have crucial roles in the enzyme activity, possibly by producing an NADP+ binding pocket.

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.