Web survey-based selection of controls for epidemiological analyses of a multi-prefectural outbreak of enterohaemorrhagic Escherichia coli O157 in Japan associated with consumption of self-grilled beef hanging tender

An outbreak of enterohaemorrhagic Escherichia coli O157 occurred in multiple prefectures of Japan in November 2009. We conducted two case-control studies with trace-back and trace-forward investigations to determine the source. The case definition was met by 21 individuals; 14 (66.7%) were hospitalised, but no haemolytic uraemic syndrome, acute encephalopathy or deaths occurred. Median age was 23 (range 12-48) years and 14 cases were male (66.7%). No significant associations with food were found in a case-control study by local public health centres, but our matched case-control study using Internet surveys found that beef hanging tender (or hanger steak), derived from the diaphragm of the cattle, was significantly associated with illness (odds ratio = 15.77; 95% confidence interval, 2.00-124.11). Pulsed-field gel electrophoresis analysis of isolates from patients and the suspected food showed five different patterns: two in faecal and food samples, and another three in patient faecal samples only, although there were epidemiological links to the meat consumed at the restaurants. Trace-back investigation implicated a common food processing company from outside Japan. Examination of the logistics of the meat processing company suggested that contamination did not occur in Japan. We concluded that the source of the outbreak was imported hanging tender. This investigation revealed that Internet surveys could be useful for outbreak investigations.

Graft-Versus-Host Disease Following Liver Transplantation: Development of a High-Incidence Rat Model and a Selective Prevention Method

Graft-versus-host disease (GvHD) following liver transplantation (LT) is a rare but serious complication with no presently available animal model and no preventive measures. To develop a rat model of GvHD after LT (LT-GvHD), we preconditioned hosts with sublethal irradiation plus reduction of natural killer (NK) cells with anti-CD8α mAb treatment, which invariably resulted in acute LT-GvHD. Compared with those in the peripheral counterpart, graft CD4⁺ CD25^- passenger T cells showed lower alloreactivities in mixed leukocyte culture. Immunohistology revealed that donor CD4⁺ T cells migrated and formed clusters with host dendritic cells in secondary lymphoid organs, with early expansion and subsequent accumulation in target organs. For selectively preventing GvHD, donor livers were perfused ex vivo with organ preservation media containing anti-TCRαβ mAb. T cell-depleted livers almost completely suppressed clinical GvHD such that host rats survived for >100 days. Our results showed that passenger T cells could develop typical LT-GvHD if resistant cells such as host radiosensitive cells and host radioresistant NK cells were suppressed. Selective ex vivo T cell depletion prevented LT-GvHD without affecting host immunity or graft function. This method might be applicable to clinical LT in prediagnosed high-risk donor-recipient combinations and for analyzing immunoregulatory mechanisms of the liver.

A cross-sectional study to quantify the prevalence of avian influenza viruses in poultry at intervention and non-intervention live bird markets in central Vietnam, 2014

In Vietnam, live bird markets are found in most populated centres, providing the means by which fresh poultry can be purchased by consumers for immediate consumption. Live bird markets are aggregation points for large numbers of poultry, and therefore, it is common for a range of avian influenza viruses to be mixed within live bird markets as a result of different poultry types and species being brought together from different geographical locations. We conducted a cross-sectional study in seven live bird markets in four districts of Thua Thien Hue Province in August and December, 2014. The aims of this study were to (i) document the prevalence of avian influenza in live bird markets (as measured by virus isolation); and (ii) quantify individual bird-, seller- and market-level characteristics that rendered poultry more likely to be positive for avian influenza virus at the time of sale. A questionnaire soliciting details of knowledge, attitude and avian influenza practices was administered to poultry sellers in study markets. At the same time, swabs and faecal samples were collected from individual poultry and submitted for isolation of avian influenza virus. The final data set comprised samples from 1,629 birds from 83 sellers in the seven live bird markets. A total of 113 birds were positive for virus isolation; a prevalence of 6.9 (95% CI 5.8-8.3) avian influenza virus-positive birds per 100 birds submitted for sale. After adjusting for clustering at the market and individual seller levels, none of the explanatory variables solicited in the questionnaire were significantly associated with avian influenza virus isolation positivity. The proportions of variance at the individual market, seller and individual bird levels were 6%, 48% and 46%, respectively. We conclude that the emphasis of avian influenza control efforts in Vietnam should be at the individual seller level as opposed to the market level.

Endoscopic evaluation of food bolus formation and its relationship with the number of chewing cycles

It is known that solid food is transported to the pharynx actively in parallel to it being crushed by chewing and mixed with saliva in the oral cavity. Therefore, food bolus formation should be considered to take place from the oral cavity to the pharynx. In previous studies, the chewed food was evaluated after the food had been removed from the oral cavity. However, it has been pointed out that spitting food out of the oral cavity interferes with natural food bolus formation. Therefore, we observed food boluses immediately before swallowing using an endoscope to establish a method to evaluate the food bolus-forming function, and simultaneously performed endoscopic evaluation of food bolus formation and its relationship with the number of chewing cycles. The subject was inserted the endoscope nasally and instructed to eat two coloured samples of boiled rice simultaneously in two ingestion conditions ('as usual' and 'chewing well'). The condition of the food bolus was graded into three categories for each item of grinding, mixing and aggregation and scored 2, 1 and 0. The score of aggregation was high under both ingestion conditions. The scores of grinding and mixing tended to be higher in subjects with a high number of chewing cycles, and the score of aggregation was high regardless of the number of chewing cycles. It was suggested that food has to be aggregated, even though the number of chewing cycles is low and the food is not ground or mixed for a food bolus to reach the swallowing threshold.

Longitudinal distortions and transversal fluctuations of an actin filament sliding on Myosin molecules

An actin filament sliding on myosin moleculesdemonstrates both longitudinal distortions and transversal fluctuationswith the linear dimension far exceeding the diameter of an actinmonomer. Local swaying of a single actin filament was identified byreading speckled fluorescent markers attached on the filament. Theaccuracy of reading each speckled marker was about 10.4 nm (r.m.s.).Longitudinal distortions of an actin filament at a low ATP concentrationof 20 μM were as much as 0.5 μm for the average filament lengthof 5.4 μm. The magnitude of transversal fluctuations was as much as60 nm, that was independent of the filament length. Both longitudinaldistortions and transversal fluctuations are suggested to play a pivotalrole for facilitating a smooth sliding movement of an actin filament.

A phase I pharmacokinetic (PK) study of MBP-426, a novel liposome encapsulated oxaliplatin

2535

Background: MBP-426 is a novel liposome encapsulated oxaliplatin (L-OHP) formulation bound to human transferrin, developed to improve the safety and efficacy of L -OHP through the prolongation of circulation time and by targeting transferrin receptors on tumor cells. In vitro, MBP-426 is effective against various human cancer cell lines. This study assessed the toxicity and safety of intravenously (IV) administered MBP-426, including defining the maximally tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics (PKs). Methods: Patients (pts) with advanced/ metastatic solid tumors refractory to conventional therapy received MBP-426 as 2–4 hrs IV infusion every 3 weeks in cohorts of 3 to 6 pts. Enrollment required age > 18 yrs, ECOG Performance Status 0–2 and adequate organ functions. Tumor response was assessed by RECIST. Plasma was sampled for PK. Results: 39 pts were dosed, median age 59 (range 27–79), 25 (64%) male. The common tumor types were colorectal 23 (60%), pancreas 3 (8%), and neuroendocrine 3 (8%). Most pts were heavily pretreated with chemotherapy or chemoradiation. 77% pts had received oxaliplatin or cisplatin. Eleven dose levels ranging from 6 to 400 mg/m2 were evaluated. At 400 mg/m2, 2/3 pts had DLT as grade 4 thrombocytopenia and prolonged thrombocytopenia (1 pt each). The recommended phase II dose is 226 mg/m2 where 1/6 pts had grade 4 thrombocytopenia. Grade 3–4 toxicities included fatigue (3 pts), hypercholesterolemia (3 pts), anemia (2 pts) and constipation (1 pt). Common grade 1–2 toxicities were nausea and/or vomiting (59%), fatigue (43%), infusion reaction (15%), thrombocytopenia (15%), anemia (13%) and peripheral neuropathy (13%). 15 pts had stable disease after 2 cycles. 3 pts with colon carcinoma refractory to conventional oxaliplatin had stable disease for 4, 5 and 6 cycles respectively, one of them had 25% decrease in target lesions. PKs of MBP-426 were dose-proportional. Main PK parameters at 226 mg/m2 were AUC 2141+419 μg.hr/ml, and t½ 89+92 hr, comparing favorably with intact L-OHP. Conclusions: MBP-426 has a favorable safety profile with thrombocytopenia as main DLT. The PK target concentration of L-OHP was exceeded at higher doses. Based on PK and toxicity profiles, the recommended dose is 226 mg/m2.

[Table: see text]

Ectopic synaptogenesis during retinal degeneration in the royal college of surgeons rat

Rod photoreceptor-specific mutations cause ectopic synapses to form between cone photoreceptor terminals and rod bipolar cell dendrites in degenerating retinas of rhodopsin transgenic (P347L) pigs and retinal degeneration mice. Since the mutations occur in rod photoreceptor-specific genes in these two models, it is not known if ectopic synaptogenesis occurs specifically due to some rod photoreceptor cell-autonomous properties of a mutation or as a general consequence of photoreceptor degeneration. In the Royal College of Surgeons (RCS) rat, a mutation in the receptor tyrosine kinase gene, Mertk, causes failure of the retinal pigment epithelial (RPE) cells to phagocytose shed photoreceptor outer segments; subsequently, both rod and cone photoreceptors die. The non-phagocytic phenotype of the RCS rat is RPE cell-autonomous and the photoreceptors degenerate secondarily. Here we show that in 35-day-old RCS rats, where a majority of rod and cone photoreceptors remained, rod bipolar cell dendrites had abnormal (flat-contact type) synaptic contacts with rod and cone terminals. Demonstration of ectopic synapses in the RCS rat suggested that ectopic synaptogenesis could occur as a result of photoreceptor degeneration, even when the rods and cones were developmentally normal. This further supported the hypothesis that ectopic synaptogenesis may be a common step in the disease progression of different forms of retinal degeneration that include photoreceptor death as a feature, such as retinitis pigmentosa.

Charge ordering and spin frustration in AlV2-x CrxO4

The relationship between charge and spin degrees of freedom in a geometrically frustrated system, AlV2-xCrxO4 spinel, is investigated. Upon Cr doping, the charge-ordered phase of AlV2O4 is rapidly suppressed and a charge-disordered phase grows up instead. It is found that the magnetic ground state is a spin-glass state dominated by geometrical frustration for both phases, but larger spin entropy remains down to low temperatures in the charge-ordered phase, possibly owing to its two-dimensional character.

Wine stimulates gastric acid secretion in isolated rabbit gastric glands via two different pathways

BACKGROUND & AIMS

Alcoholic beverages such as beer and wine are well known to potently stimulate gastric acid secretion, most probably through an increase in circulating gastrin level. The present study examined whether or not wine stimulates gastric acid secretion by a direct effect on parietal cells, enterochromaffin-like (ECL) cells or both.

METHODS

Gastric mucosa was isolated from female Japanese white rabbits and gland specimens were prepared by the collagenase digestion method. Acid secretion was assessed by gland accumulation of [14C] aminopyrine. The effects of red wine, ethanol, non-alcoholic wine and drugs were determined by incubating gastric glands with aminopyrine. Radioactivity in solubilized glands was determined by a liquid scintillation counting.

RESULTS

Neither wine nor ethanol (diluted 1 : 10(2) to 1 : 10(4)) had any effect on gastric acid secretion, whereas non-alcoholic wine stimulated acid secretion in a dose-dependent manner. All substances, however, significantly stimulated gastric acid secretion in IBMX (phosphodiesterase inhibitor)-pretreated glands. S-0509 (a CCK-2 receptor antagonist) and atropine had no effect on acid secretion stimulated by wine, ethanol or non-alcoholic wine in IBMX-pretreated glands. Famotidine and omeprazole significantly inhibited the acid secretion resulting from all of the above stimulants. BAPTA (an intracellular Ca2+ chelator) inhibited acid secretion stimulated with wine or ethanol in a dose-dependent manner, but did not inhibit secretion stimulated by non-alcoholic wine.

CONCLUSIONS

Wine was found to stimulate gastric acid secretion in gastric glands via two pathways, by an ethanol-induced increase in the concentration of intracellular Ca2+ in parietal cells, and by histamine release from ECL cells potentially induced by constituents present in wine.

Kupffer cell-mediated recruitment of rat dendritic cells to the liver: roles of N-acetylgalactosamine-specific sugar receptors

BACKGROUND & AIMS

Tissue recruitment of dendritic cells (DCs) is essential for antigen presentation. This study aimed to examine cellular and molecular mechanisms for DC recruitment to the liver.

METHODS

Purified rat DCs were injected into circulation and their traffics were analyzed in normal and Kupffer cell-depleted rats by intravital confocal microscopy and immunohistology. Affinities of DCs to sinusoidal cells were examined by a cell-binding assay. DC precursor recruitment was induced by particulate injection.

RESULTS

Both DC precursors and DCs at the antigen-transporting stage could be recruited to the liver, and their majority initially showed a selective binding to Kupffer cells. In the Kupffer cell-depleted rats, DCs could neither be recruited to the liver nor adhere to sinusoidal walls. Pretreatment with varied monosaccharides showed that sugar residues consisting of N-acetylgalactosamine were necessary for this binding. The binding was calcium-dependent, implying the C-type lectin involvement. Furthermore, DCs could endocytose N-acetylgalactosamine polymers in a receptor-specific manner.

CONCLUSIONS

The DC-Kupffer cell binding through N-acetylgalactosamine-specific C-type lectin-like receptors is crucial for DC recruitment to the liver. Rat DCs at least partly possess receptors for endocytosis of galactosylated antigens. These DC receptors as well as Kupffer cell lectins are presumably responsible for this binding.

Role of Deltex-1 as a transcriptional regulator downstream of the Notch receptor

Intercellular signaling through the cell-surface receptor Notch plays important roles in a variety of developmental processes as well as in pathogenesis of some human cancers and genetic disorders. However, the mechanisms by which Notch signals are transduced into cells still remain elusive. Here we investigated the signaling mechanisms for Notch in the cell fate control of neural progenitor cells. We show that Deltex-1 (DTX1), a mammalian homolog of Drosophila Deltex, mediates a Notch signal to block differentiation of neural progenitor cells. We found that a significant fraction of DTX1 proteins were localized in the nucleus and physically interacted with the transcriptional coactivator p300. Through its binding to p300, DTX1 inhibited transcriptional activation by the neural-specific helix-loop-helix-type transcription factor MASH1, and this mechanism is likely responsible for the differentiation inhibition of neural progenitor cells. Our results further suggest that DTX1 regulates transcription independently of the previously characterized Notch signaling pathway involving RBP-J and HES1/HES5. Thus, DTX1 serves as an important signaling component downstream of Notch that regulates transcription in the nucleus.

[11C]Raclopride binding was reduced in vivo by sigma(1) receptor ligand SA4503 in the mouse brain, while [11C]SA4503 binding was not by raclopride

[11C]Raclopride is widely used as a representative dopamine D(2)-like receptor ligand in positron emission tomography (PET) studies, and [11C]1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride ([11C]SA4503) is a recently developed selective ligand for mapping sigma(1) receptors in the brain. The striatal uptake of [11C]raclopride in mice was reduced by co-injection of an excess amount of SA4503, in spite of the fact that raclopride had no effect on the brain uptake of [11C]SA4503 as shown in a previous study. The blocking effect of SA4503 on the striatal uptake of [11C]raclopride was dose-dependent, but disappeared by 1 h or 6 h after intraperitoneal injection of SA4503. The brain uptake of [11C]SA4503 was not affected by a dopamine transporter inhibitor GBR 12909, nor was [11C]beta-CIT-FP inhibited by SA4503. The IC(50) values of raclopride for sigma(1) and sigma(2) receptor subtypes measured in vitro were 11800 nM and 4950 nM, respectively, suggesting that the affinity was too low for [11C]raclopride to bind in vivo to sigma receptors. On the other hand, the IC(50) value of SA4503 for dopamine D(2) receptors was 470 nM, that is approximate 1/25 of the affinity of raclopride for the dopamine D(2) receptors. Therefore, possible explanations for the partial blocking effects of SA4503 on the striatal uptake of [11C]raclopride are: (1) an excess amount of SA4503 may reduce the [11C]raclopride uptake due to its low affinity for dopamine D(2) receptors, or (2) SA4503 may enhance endogenous dopamine release, which results in the competitive inhibition of the [11C]raclopride uptake. These findings support that both [11C]raclopride and [11C]SA4503 are selective in vivo ligands for dopamine D(2)-like receptors and sigma(1) receptors, respectively, in spite of the partial blocking effect of SA4503 on the striatal uptake of [11C]raclopride.

Metabolic changes in human CD36 deficiency displayed by glucose loading

Previous in vitro studies have shown that CD36 participates in cellular fatty acid (FA) uptake. In vivo evidence for a physiologic role of CD36 in this process is poor and mostly obtained in animals. To examine the metabolic role of human CD36, we performed a glucose loading test for normals (n = 16) and subjects with CD36 deficiency, both Type I (n = 5) and Type II (n = 16). After 30 min, FA levels had fallen by 60.1% in normals but by only 31.7% in Type II deficiency (P <0.01 vs. normals) and 16.5% in Type I deficiency which remained significantly higher than the other two groups out to 2 h. Further, changes in triglyceride and glucose metabolism were observed in the both types of CD36 deficiency. Impaired fast FA clearance by muscle and consequently increased hepatic FA uptake seem to underlie these changes. We conclude that human CD36 deficiency causes systemic metabolic changes.

Efficacy of the novel selective platelet-derived growth factor receptor antagonist CT52923 on cellular proliferation, migration, and suppression of neointima following vascular injury

Exaggerated or inappropriate signaling by the platelet-derived growth factor receptor (PDGFR) tyrosine kinase has been implicated in a wide variety of diseases. Thus, a series of piperazinyl quinazoline compounds were identified as potent antagonists of the PDGFR by screening chemical libraries. An optimized analog, CT52923, was shown to be an ATP-competitive inhibitor that exhibited remarkable specificity when tested against other kinases, including all members of the closely related PDGFR family. The PDGFRs and stem cell factor receptor were inhibited with an IC(50) of 100 to 200 nM, while 45- to >200-fold higher concentrations of CT52923 were required to inhibit fms-like tyrosine kinase-3 and colony-stimulating factor-1 receptor, respectively. Other receptor tyrosine kinases, cytoplasmic tyrosine kinases, serine/threonine kinases, or members of the mitogen-activated protein kinase pathway were not significantly inhibited at 100- to 1000-fold higher concentrations. In addition, this compound also demonstrated specificity for inhibition of cellular responses. Platelet-derived growth factor-induced smooth muscle cell migration or fibroblast proliferation was found to be blocked by CT52923 with an IC(50) of 64 and 280 nM, respectively, whereas 50- to 100-fold higher concentrations were required to inhibit these responses when induced with fibroblast growth factor. To investigate the effect of CT52923 on PDGFR signaling, in vivo studies demonstrated that CT52923 could significantly inhibit neointima formation following carotid artery injury by oral administration in the rat. Therefore, PDGFR antagonism by CT52923 could be a viable strategy for the prevention of clinical restenosis or the treatment of other human diseases involving PDGFR signaling.

Neurosteroids stimulate G protein-coupled sigma receptors in mouse brain synaptic membrane

Dehydroepiandrosterone, its sulfate (DHEAS) and pregnenolone sulfate, representative neurosteroids as well as (+)-pentazocine concentration-dependently stimulated the [35S]GTPgammaS binding in synaptic membranes of mouse prefrontal cortex. These stimulations were blocked by NE-100, a sigma-receptor antagonist, and by progesterone, another type of neurosteroid. The DHEAS-induced stimulation was blocked by the pertussis toxin (PTX)-treatment, and completely recovered by reconstitution of PTX-treated membranes with recombinant G(i1), but not with G(oA). DHEAS also stimulated the [35S]GTPgammaS binding in the coronal sections of mouse brain in NE-100- or progesterone-reversible manner. These findings suggest that some neurosteroids may act on metabotropic sigma receptors, and this study may be the first to show the coupling of neurosteroid binding site and G(i).

Cell motility and thermodynamic fluctuations tailoring quantum mechanics for biology

Cell motility underlying muscle contraction is an instance of thermodynamics tailoring quantum mechanics for biology. Thermodynamics is intrinsically multi-agential in admitting energy consumers in the form of energy-deficient thermodynamic fluctuations. The onset of sliding movement of an actin filament on myosin molecules in the presence of ATP molecules to be hydrolyzed demonstrates that thermodynamic fluctuations transform their nature so as to accommodate themselves to energy transduction subject to the first law of thermodynamics. The transition from transversal to longitudinal fluctuations of an actin filament with the increase of ATP concentration coincides with the change in the nature of energy consumers acting upon thermal energy in the light of the first law, eventually embodying a uniform sliding movement of an actin filament.

Human CC chemokine liver-expressed chemokine/CCL16 is a functional ligand for CCR1, CCR2 and CCR5, and constitutively expressed by hepatocytes

Liver-expressed chemokine (LEC)/CCL16 is a human CC chemokine selectively expressed in the liver. Here, we investigated its receptor usage by calcium mobilization and chemotactic assays using mouse L1.2 pre-B cell lines stably expressing a panel of 12 human chemokine receptors. At relatively high concentrations, LEC induced calcium mobilization and chemotaxis via CCR1 and CCR2. LEC also induced calcium mobilization, but marginal chemotaxis via CCR5. Consistently, LEC was found to bind to CCR1, CCR2 and CCR5 with relatively low affinities. The binding of LEC to CCR8 was much less significant. In spite of its binding to CCR5, LEC was unable to inhibit infection of an R5-type HIV-1 to activated human peripheral blood mononuclear cells even at high concentrations. In human liver sections, hepatocytes were strongly stained by anti-LEC antibody. HepG2, a human hepatocarcinoma cell line, was found to constitutively express LEC. LEC was also present in the plasma samples from healthy adult donors at relatively high concentrations (0.3--4 nM). Taken together, LEC is a new low-affinity functional ligand for CCR1, CCR2 and CCR5, and is constitutively expressed by liver parenchymal cells. The presence of LEC in normal plasma at relatively high concentrations may modulate inflammatory responses.

Metabotropic neurosteroid/sigma-receptor involved in stimulation of nociceptor endings of mice

In peripheral nociceptive flexor test, SA4503, (+)-pentazocine, and (+)-3-(hydroxyphenyl)-N-(1-propyl)piperidine, representative sigma-receptor agonists, elicited dose-dependent flexor responses. These responses were blocked by sigma-receptor antagonists NE-100 or BD1063, but not by pretreatments with antisense oligodeoxynucleotide for sigma1 binding protein. The sigma-agonists' nociception is attributed to the substance P (SP) release from nociceptor endings through activations of Galpha(i1) and phospholipase C (PLC). On the other hand, attomolar doses of neurosteroids such as dehydroepiandrosterone sulfate (DHEAS) and pregnenolone sulfate caused similar nociception, and they were blocked by progesterone (PROG). However, DHEAS nociception was not affected by pertussis toxin, but was completely inhibited by a PLC inhibitor or thapsigargin. Although the nociception by lower doses of DHEAS was abolished by diphenhydramine (DPH), H1 antagonist, there were dose-dependent responses by high doses of DHEAS in the presence of DPH. The responses by DHEAS in the presence of DPH were blocked by NE-100, and those by (+)-pentazocine were blocked by PROG. All these findings suggest that two novel types of neurosteroid receptors exist, neuronal NS1/sigma-type, which mediates activation of Galpha(i1) by neurosteroids and sigma-agonists, followed by SP release from nociceptor endings; and NS2 type, which mediates histamine release from mast cells by very low doses of neurosteroids.

Crystal structure of Bacillus subtilis isocitrate dehydrogenase at 1.55 A. Insights into the nature of substrate specificity exhibited by Escherichia coli isocitrate dehydrogenase kinase/phosphatase

Isocitrate dehydrogenase from Bacillus subtilis (BsIDH) is a member of a family of metal-dependent decarboxylating dehydrogenases. Its crystal structure was solved to 1.55 A and detailed comparisons with the homologue from Escherichia coli (EcIDH), the founding member of this family, were made. Although the two IDHs are structurally similar, there are three notable differences between them. First, a mostly nonpolar beta-strand and two connecting loops in the small domain of EcIDH are replaced by two polar alpha-helices in BsIDH. Because of a 13-residue insert in this region of BsIDH, these helices protrude over the active site cleft of the opposing monomer. Second, a coil leading into this cleft, the so-called "phosphorylation" loop, is bent inward in the B. subtilis enzyme, narrowing the entrance to the active site from about 12 to 4 A. Third, although BsIDH is a homodimer, the two unique crystallographic subunits of BsIDH are not structurally identical. The two monomers appear to differ by a domain shift of the large domain relative to the small domain/clasp region, reminiscent of what has been observed in the open/closed conformations of EcIDH. In Escherichia coli, IDH is regulated by reversible phosphorylation by the bifunctional enzyme IDH kinase/phosphatase (IDH-K/P). The site of phosphorylation is Ser(113), which lies deep within the active site crevice. Structural differences between EcIDH and BsIDH may explain disparities in their abilities to act as substrates for IDH-K/P.

The internalist enterprise on constructing cell motility in a bottom-up manner

Quantum coherence in the biological realm is constructed internally in a bottom-up manner. In particular, an actin filament sliding on myosin molecules in the presence of ATP to be hydrolyzed as a functional unit of muscle contraction exhibits magnetization as a marker of quantum coherence. The uniqueness of quantum coherence in biology is found in precipitating synchronous time in interaction from the interacting energy quanta, each of which has carried with itself synchronous time unique to the quantum in isolation. It exhibits a marked contrast to quantum coherence met in low temperature physics, in the latter of which no transformation of the nature of synchronous time is entertained.

A human protein with sequence similarity to Drosophila mastermind coordinates the nuclear form of notch and a CSL protein to build a transcriptional activator complex on target promoters

Mastermind (Mam) has been implicated as an important positive regulator of the Notch signaling pathway by genetic studies using Drosophila melanogaster. Here we describe a biochemical mechanism of action of Mam within the Notch signaling pathway. Expression of a human sequence related to Drosophila Mam (hMam-1) in mammalian cells augments induction of Hairy Enhancer of split (HES) promoters by Notch signaling. hMam-1 stabilizes and participates in the DNA binding complex of the intracellular domain of human Notch1 and a CSL protein. Truncated versions of hMam-1 that can maintain an association with the complex behave in a dominant negative fashion and depress transactivation. Furthermore, Drosophila Mam forms a similar complex with the intracellular domain of Drosophila Notch and Drosophila CSL protein during activation of Enhancer of split, the Drosophila counterpart of HES. These results indicate that Mam is an essential component of the transcriptional apparatus of Notch signaling.

Retinoic acids reduce matrilysin (matrix metalloproteinase 7) and inhibit tumor cell invasion in human colon cancer

All-trans retinoic acid (ATRA), 9-cis retinoic acid and 13-cis retinoic acid are naturally occurring retinoids used in the prevention and therapy of various preneoplastic and neoplastic diseases. It was previously reported that matrilysin, one of the matrix metalloproteinases (MMP-7), plays a critical role in the invasion and metastasis of gastrointestinal cancers. Moreover, it has been shown that ATRA downregulates matrilysin expression and prevents in vitro invasion by colon cancer cells. In this study, three retinoids were used, both in Matrigel invasion assays and in subcutaneous xenografts in mice, to evaluate the effects of retinoids on invasion by colon cancer cell lines (CHC-Y1, DLD-1, HT-29, BM314, CaR-1 and WiDr). All three retinoic acids tested reduced matrilysin expression and suppressed the invasiveness of colon cancer cell lines in vitro. Retinoic acids also reduced tumor invasion in mice without influencing tumor growth. Matrilysin expression in these tumors was clearly reduced. These data support the use of retinoic acids as useful reagents to manage patients with colorectal carcinoma.

Trafficking of host- and donor-derived dendritic cells in rat cardiac transplantation: allosensitization in the spleen and hepatic nodes

BACKGROUND

Kinetics and role of host and donor dendritic cells (DCs) in transplantation immunity are still ill-defined. Using a rat cardiac transplantation model, we studied DC trafficking and sites for allosensitization.

METHODS

Host and donor DCs were defined as host- or donor-type class II major histocompatibility complex antigen single-positive cells by double-immunostaining. Proliferative response of both donor and host cells were also analyzed.

RESULTS

Host DCs were recruited to the graft soon after transplantation. These cells represented definitive precursors because of high labeling index by a continuous bromodeoxyuridine infusion, their small round shape, and their putative bone marrow origin. Donor interstitial DCs showed a significant self-replicating capability. Both recruited host DCs in a regraft experiment and donor DCs preferentially performed blood-borne migration to the T-cell area of host spleen. Furthermore, they also migrated to the T-cell area of hepatic lymph nodes after executing the sinusoids-lymph translocation as a novel pathway for these DCs. Selectively at their migration sites, a strong T-cell proliferative response occurred, which preceded that in the graft tissues. Removal of spleen and hepatic lymph nodes significantly prolonged the mean graft survival time.

CONCLUSION

We conclude that allogeneic heart transplantation induces the recruitment of host DC precursors to the graft tissues and the blood-borne migration of both recruited host and donor DCs to the host spleen and hepatic nodes where effector cells are predominantly sensitized.

Evaluation of the retinal nerve fiber layer thickness in eyes with idiopathic macular holes

PURPOSE

To compare the retinal nerve fiber layer thickness in eyes with idiopathic macular holes and age-matched normal controls using scanning laser polarimeter.

METHODS

The retinal nerve fiber layer thickness was measured in 40 eyes of 40 consecutive patients with idiopathic macular hole (stage 1, 10 eyes; stage 2, eight eyes; stage 3, 15 eyes; stage 4, seven eyes) and 40 eyes of 40 age-matched normal controls with a scanning laser polarimeter. The retinal nerve fiber layer thickness within a 10-pixel-wide ellipse located concentrically with the disk and located 1.5-disk diameters from the center of the disk was measured. The mean overall retinal nerve fiber layer thickness of the peripapillary retina, four 90-degree quadrants, and 16 equal sectors of every 22.5 degrees was calculated for both groups. The retinal nerve fiber layer thickness in the two groups was statistically compared.

RESULTS

The mean retinal nerve fiber layer thickness measurement for the overall peripapillary retina and for three of the four 90-degree quadrants was not significantly different between the two groups. However, the temporal 90-degree quadrant was significantly thinner in the macular hole group (47.2 versus 54.6 microm, P =.026). For the 16 sectors of 22.5 degrees, the lower three sectors of the four sectors in the temporal quadrant were thinner in the macular hole group (P <.05).

CONCLUSIONS

The retinal nerve fiber layer thickness of the papillomacular area is thinner in eyes with idiopathic macular hole than that in normal eyes. The progressive thinning of the retinal nerve fiber layer thickness as the stage of the macular hole advances may suggest that surgery should be done at the earliest stage.

Individual differences in urinary cotinine levels in Japanese smokers: relation to genetic polymorphism of drug-metabolizing enzymes

Urinary cotinine, one of the main metabolites of nicotine, has been widely used as a biomarker for assessment of direct or passive exposure to cigarette smoke. However, there is wide variation of the cotinine level among smokers who smoke the same number of cigarettes. To use urinary cotinine as a proper exposure-biomarker for cigarette smoke, interindividual variations of cotinine formation must be considered. Therefore, we studied the effects of genetic polymorphisms in drug metabolic enzymes on urinary cotinine levels among 190 male Japanese smokers (ages 19-66 years; mean, 40.6 years). Genetic polymorphisms in cytochrome P-450s (CYP1A1, CYP2A6, CYP2E1), and aldehyde dehydrogenase 2 (ALDH2) were determined by analyzing DNA isolated from peripheral blood. Cotinine in morning spot urine was analyzed by high-performance liquid chromatography. Lifestyle, i.e., smoking, alcohol consumption, and intake of coffee or tea, was examined using a questionnaire. The number of cigarettes smoked and CYP2A6 polymorphism were significantly associated with the urinary cotinine level. Especially, the urinary cotinine levels was drastically lower in CYP2A6-deleted homozygous (CYP2A6*4/*4) subjects than in CYP2A6*1 allele-positive subjects. The polymorphism in the CYP2E1 5'-flanking region was related to the urinary cotinine level in intermediate smokers (who smoke 11-20 cigarettes/day; P < 0.01). Polymorphisms in CYP1A1 or ALDH2, and consumption of alcohol, coffee, or tea were not associated with the urinary cotinine level.

Asialoglycoprotein receptors on rat dendritic cells: possible roles for binding with Kupffer cells and ingesting virus particles

Rat dendritic cells selectively bind to Kupffer cells in vitro. The present study aimed to reveal adhesion molecules on dendritic cells and their roles in the host defense system. The in situ binding assay to examine the effects of pretreatment of dendritic cells with various kinds of monosaccharides suggested that N-acetylgalactosamine was necessary for the binding of dendritic cells to Kupffer cells. This binding was also attenuated when dendritic cells were injected into an ex vivo liver perfusion circuit together with N-acetyl-galactosamine. It was further shown that the majority of rat lymph dendritic cells and some interdigitating dendritic cells in the lymph nodes possessed asialoglycoprotein receptors specific for N-acetylgalactosamine/galactose as detected by immunostaining. Lymph dendritic cells could ingest virus particles in vitro, even though these cells showed no phagocytic activity for latex particles. The results indicate that rat dendritic cells possess asialoglycoprotein receptors which are probably utilized to recognize Kupffer cells for their recruitment to the liver and possibly to recognize virus particles prior to phagocytosis.

In vivo roles of donor and host dendritic cells in allogeneic immune response: cluster formation with host proliferating T cells

Possible roles of dendritic cells (DCs) in allogeneic immune responses in host lymphoid tissues were characterized in situ by using rat DC transfer and cardiac transplantation models. When allogeneic DCs were intravenously injected, these cells selectively migrated to the T-cell area of hepatic lymph nodes, with peak accumulation at 18 h after injection. Donor DCs and proliferating host T cells formed clusters (rosettes) in which the T-cell proliferative response started. The donor DCs were CD80(+) CD86(+) and, ultrastructurally, were in intimate contact with lymphoblasts within the rosettes. As a novel finding, some of the migrated donor DCs were quickly phagocytosed by putative host interdigitating DCS: By 48 h, the remaining donor DCs had disintegrated within the rosettes. Host interdigitating DCs also formed rosettes throughout the T-cell area, and their kinetics correlated well with that of the T-cell proliferation. In the cardiac allograft model, a few donor DCs selectively migrated to the host spleen and hepatic nodes. Rosette formation by donor and host DCs, phagocytosis of donor DCs, and the T-cell proliferative response occurred in much the same fashion as they did in the first experiment. We conclude that the donor rosettes at the early stage represent the sites of direct allosensitization and those at the late stage represent donor-DC killing. Host rosettes are the sites of T-cell proliferation. In this structure, phagocytosed donor-DC-derived antigens are presumably indirectly presented.

Comparative study of retinal nerve fiber layer loss in normal-tension glaucoma and chronic open-angle glaucoma

PURPOSE

To clarify whether loss of the retinal nerve fiber layer in normal-tension glaucoma (NTG) differs from that in chronic open-angle glaucoma (COAG).

METHODS

Using a scanning laser polarimeter, retinal nerve fiber layer thickness (RNFLT) was measured in 21 patients with NTG, 21 patients with COAG and 21 normal controls. The three groups were matched for age, and the NTG and COAG groups were matched for visual field loss.

RESULTS

The mean RNFLT was significantly less in the NTG than in the control group and less in the COAG than in the controls and NTG group. Although the correlations between the parameters of RNFLT and homotopic visual field measurements were significant in COAG, none of the correlations were significant in NTG.

CONCLUSIONS

The present results suggest that loss of the retinal nerve fiber layer in NTG differs from that in COAG.

Detection of myocardial viability using rest-redistribution thallium-201 imaging in a stress 99Tcm-tetrofosmin/rest thallium-201 dual-isotope protocol

This study investigated the utility of optional thallium-201 (201Tl) imaging for detecting myocardial viability in the stress 99Tcm-tetrofosmin/rest 201Tl dual-isotope protocol. Seventy-nine patients with old myocardial infarction and 25 patients with acute myocardial infarction underwent acquisition of three consecutive 201Tl images (early, intermediate and delayed) using the dual-isotope protocol. A polar map was created and defect scores (extent and severity) were determined by comparison with normal control data. Fluorodeoxyglucose positron emission tomography was also performed in 16 patients with old myocardial infarction. In patients with old infarction, the severity score decreased significantly from the early to the intermediate images, and decreased further on the delayed images. In patients with acute infarction, the score increased from the early to the intermediate images, but not on the delayed images. Regional uptake on the delayed images showed a better correlation with the fluorodeoxyglucose images than that on the early images. Redistribution on the delayed images was exclusively observed in the myocardial segments with less uptake than that estimated by fluorodeoxyglucose. In conclusion, addition of delayed 201Tl imaging to the dual-isotope protocol could improve the sensitivity for detecting myocardial viability.

Murine homologs of deltex define a novel gene family involved in vertebrate Notch signaling and neurogenesis

Notch signaling plays an important role in cell-fate specification in multicellular organisms by regulating cell-cell communication. The Drosophila deltex gene encodes a modulator of the Notch pathway that has been shown to interact physically with the Ankyrin repeats of Notch. We isolated four distinct cDNAs corresponding to mouse homologs of deltex - mouse Deltex1 (MDTX1), mouse Deltex2 (MDTX2), mouse Deltex2DeltaE (MDTX2DeltaE), and mouse Deltex3 (MDTX3). Deduced amino acid sequences of these four cDNAs showed a high degree of similarity to Drosophila Deltex and its human homolog, DTX1 throughout their lengths, even though they possess distinct structural features. MDTX proteins formed homotypic and heterotypic multimers. We found that these genes were expressed in the central, peripheral nervous system and in the thymus, overlapping with those of mouse Notch1. In mammalian tissue culture cells, overexpression of any of the four mouse deltex homologs suppressed the transcriptional activity of E47, a basic helix-loop-helix (bHLH) protein, in a manner similar to suppression by an activated form of human Notch1 or human DTX1. In addition, overexpression of MDTX2 and MDTX2DeltaE in C2C12 cells under differentiation-inducing conditions suppressed the expression of myogenin, one of the myogenic transcriptional factors; this was also similar to a previously reported activity of constitutively activated Notch. Furthermore, misexpression of any of the MDTX genes in Xenopus embryos resulted in an expansion of the region expressing the neural cell adhesion molecule (N-CAM) gene, a marker for the neuroepithelium. Collectively, our results suggest that these mouse deltex homologs are involved in vertebrate Notch signaling and regulation of neurogenesis.

In vivo migration of rat dendritic cells

Dendritic cells (DCs) comprise a dynamic cellular system with a continuous traffic throughout the body. DCs connect nonlymphoid and lymphoid tissues via the lymph and blood, and transport antigenic information from most parts of the body to the immune system (1). To understand the migratory behavior of DCs in vivo is very important, because in different immunological situations, this behavior could change easily and, in turn, greatly affect immune responses (2). Factors that determine the behavior of DCs, such as adhesion molecules, could potentially be the targets for manipulating and regulating immune responses. The study of DC migration, therefore, should provide useful information for understanding the role of DCs not only in local but also in systemic host-defense mechanisms (3). The aim of this chapter is to introduce several useful methods that help to examine DC migration in vivo.

Time-dependent nephrotoxicity associated with daily administration of cisplatin in mice

The chronopharmacokinetics and chronopharmacodynamics of cisplatin were studied in a mouse model to reveal the mechanisms of dosing time-dependent nephrotoxicity induced by daily administration. Chronotoxicity was tested by daily intraperitoneal injections of cisplatin (6mg kg(-1)) for 5 days at four time points (04:00, 10:00, 16:00 and 22:00h) in BALB/c mice (n = 6 in each group). After following the changes in body weight, serum concentrations of blood urea nitrogen (BUN) and creatinine obtained on day 6 were compared. The results showed diurnal variations in cisplatin toxicity, with the 04:00 and 16:00h time points the best and the worst, respectively. We then measured platinum concentrations in blood, liver and kidney and compared the results of the 04:00 and 16:00 h groups (n = 4 in each group). Kidney sensitivity to cisplatin alone, lipopolysaccharide (LPS) alone, cisplatin with LPS and saline (control) were also measured using a tissue culture system (a measurement system of interleukin-6 (IL-6) production) between the 04:00 and the 16:00 h groups (n = 4 in each group). These results showed no significant difference in platinum accumulation between the two groups. IL-6 production was higher in the 16:00 h group than in the 04:00 h group after saline injection alone (P < 0.05). Cisplatin treatment alone did not increase IL-6 production. However, IL-6 levels were markedly augmented by cisplatin with LPS. In conclusion, chrononephrotoxicity induced by daily cisplatin administration does not only depend on cisplatin accumulation, but might also depend on kidney sensitivity to diurnal variations in inflammatory reaction without direct cisplatin toxicity.

Effect of mental stress on left ventricular ejection fraction and its relationship to the severity of coronary artery disease

To evaluate the relationship between the mental stress-induced decrease in left ventricular ejection fraction (LVEF) and the severity of exercise-induced ischaemia, 20 patients with stable coronary artery disease (CAD) underwent radionuclide ventriculography during mental stress testing and stress myocardial perfusion single-photon emission tomography (SPET). We also examined whether changes in haemodynamic and neurohormonal parameters are related to changes in LVEF during mental stress. The LVEF decreased from 54.8% +/- 17.7% to 49.8% +/- 16.2% with mental stress (P < 0.0005). Ten of the 20 patients (50.0%) had a > or = 5% decrease in LVEF The remaining ten patients had no or a <5% decrease in LVEF There was a significant correlation between the change in LVEF during mental stress and the size of the reversible defect on stress myocardial perfusion SPET (r = -0.80, P < 0.0005), with close regional correspondence (75% identical). This correlation was less strong in the 12 patients with a total defect score at rest of <10 (r = -0.69, P = 0.014) than in the eight patients with a total defect score at rest of > or = 10 (r = -0.94, P = 0.001). The changes in blood pressure and heart rate were not significantly correlated with the change in LVEF, but the percent change in adrenaline concentration correlated with the change in LVEE It is suggested that mental stress impairs systolic function by inducing transient myocardial ischaemia. The effect of neurohormonal responses during mental stress on LV systolic function may also be important in patients with CAD.

Synthesizing oligomers from monomeric nucleotides in simulated hydrothermal environments

Dimers and trimers of adenosine monophosphate (AMP) were synthesized from AMP in environments simulating hot vents on the sea floor of the primitive Earth. The simulated environments were made in the flow reactor, in which an aqueous solution of reactants was circulated from the hot to the cold region repeatedly. The oligomerization proceeded most significantly when the hot reaction solution at about 110 degrees C was abruptly ejected into the cold environment maintained at about 0 degree C.

Hydrothermal circulation of seawater through hot vents and contribution of interface chemistry to prebiotic synthesis

Synthesizing oligopeptides from glycine and alanine in a flow reactor, which stimulates constant hydrothermal circulation of seawater through hot vents on the primitive Earth, demonstrated that an exponential growth of the products is possible. The initial rapid growth of the product is a consequence of using the products formed in one cycle as the starting materials for the cycle of synthesis.