Cyanide Formation in Freezer Stored Foods: Freezing of a Glycine and Nitrite Mixture

Freezing is not always the best way to keep foods safely. Some reactions are known to be accelerated in ice. Furthermore, some other reactions that are not observed in solution are also promoted in ice. We found that the formation of nitrosamines through the reaction of an amine with a nitrite is accelerated in ice. Surprisingly, cyanide is formed through the reaction of glycine with nitrite in ice but not in solution. Amines are present in many kinds of foods. Nitrite is present in vegetables and is used as a food coloring agent and to inhibit the reproduction of Clostridium botulinum. The maximum amount of cyanide formed reaches a dangerous level, and the intake of this formed cyanide in a few tens of cubic centimeters causes some people to get headaches. These facts suggest that hazardous compounds could be generated in frozen processed foods. We report here the formation of cyanide and its possible formation pathway in ice. Finally, we propose a way to prevent cyanide formation in food under frozen conditions.

Acceleration and Reaction Mechanism of the N-Nitrosation Reaction of Dimethylamine with Nitrite in Ice

Some reactions (e.g., oxidation of nitrite, denitrification of ammonium) are accelerated in freeze-concentrated solution (FCS) compared to those in aqueous solution. Ice is highly intolerant to impurities, and the ice excludes those that would accelerate reactions. Here we show the acceleration of the N-nitrosation reaction of dimethylamine (DMA) with nitrite to produce N-nitrosodimethylamine (NDMA) in FCS. NDMA is a carcinogenic compound, and this reaction is potentially accelerated in frozen fish/meat. The eaction rate of the N-nitrosation reaction becomes fastest at specific pH. This means that it is a third-order reaction. Theoretical pH values of the peak in the third-order reaction are higher than the experimental one. Freeze-concentration of acidic solution causes pH decrement; however, the freeze-concentration alone could not explain the difference of pH values. The theoretical value was obtained under the assumption that no solute took part in ice. However, solutes are incorporated in ice with a small distribution coefficient of solutes into ice. This small incorporation enhanced the decrement of pH values. Using the distribution coefficient of chloride and sodium ion and assuming those of nitrite and DMA to explain the enhancement, we succeeded in estimating the distribution coefficients of nitrite: 2 × 10^-3 and DMA: 3 × 10^-2.

Alu-Alu fusion sequences identified at junction sites of copy number amplified regions in cancer cell lines

Alu elements are short, ∼300-bp stretches of DNA and are the most abundant repetitive elements in the human genome. A large number of chromosomal rearrangements mediated by Alu-Alu recombination have been reported in germline cells, but only a few in somatic cells. Cancer development is frequently accompanied by various chromosomal rearrangements including gene amplification. To explore an involvement of Alu-Alu fusion in gene amplification events, we determined 20 junction site sequences of 5 highly amplified regions in 4 cancer cell lines. The amplified regions exhibited a common copy number profile: a stair-like increase with multiple segments, which is implicated in the breakage-fusion-bridge (BFB) cycle-mediated amplification. All of the sequences determined were characterized as head-to-head or tail-to-tail fusion of sequences separated by 1-5 kb in the genome sequence. Of these, 4 junction site sequences were identified as Alu-Alu fusions between inverted, paired Alu elements with relatively long overlapping sequences of 17, 21, 22, and 24 bp. Together with genome mapping data of Alu elements, these findings suggest that when breakages occur at or near inverted, paired Alu elements in the process of BFB cycle-mediated amplification, sequence homology of Alu elements is frequently used to repair the broken ends.

Chemotherapy-related hypersensitivity reaction in Japanese patients with gynecologic malignancy

PURPOSE OF INVESTIGATION

Chemotherapy-related hypersensitivity reaction seems to be problematic in the safe management of chemotherapy. In this study we investigated chemotherapy-related hypersensitivity reaction in patients with gynecologic malignancy.

METHODS

Between January 2009 and December 2010, we examined hypersensitivity reaction (> or = grade2) using the Common Terminology Criteria for Adverse Events (CTCAE) v.4.0. We analyzed the incidence, clinical features, management, and outcome.

RESULTS

We administered over 1,057 infusions (24 regimens) to 205 patients. We found a total of four hypersensitivity reactions (> or = grade 2) cases (carboplatin: 2; nedaplatin: 1; docetaxel: 1). Signs and symptoms were varied. In two cases, the same regimen was rechallenged by using anti-allergic drugs. The docetaxel case was successful. The carboplatin case was not successful.

CONCLUSION

Chemotherapy-related hypersensitivity reaction (> or = grade2) does not occur frequently. In the case of platinum, especially, carboplatin, re-administering after hypersensitivity reaction should be done carefully though platinum is a key drug in patients with gynecologic malignancies.

Coamplification of multiple regions of chromosome 2, including MYCN, in a single patchwork amplicon in cancer cell lines

Coamplification of multiple segments of chromosome 2, including an MYCN-bearing segment, was examined in 2 cancer cell lines, NCI-H69 (lung cancer) and IMR-32 (neuroblastoma). High-resolution array-CGH analysis revealed 13 and 6 highly amplified segments located at different sites in chromosome 2 in NCI-H69 and IMR-32, respectively. FISH analysis demonstrated that these segments were co-localized in double minutes in NCI-H69 and in homogeneously staining regions in IMR-32. Connectivity of the segments was determined by a PCR assay using designed primer sets. It was found that all the segments were connected to each other irrespective of their order and orientation against the genome sequence, and a single chain-like cluster was configured in both cell lines. Such patchwork structures of the amplicons suggest the possibility that massive genomic rearrangements, explained by the single catastrophic event model, are involved in the formation of the amplicons, enabling the coamplification of different chromosomal regions including the MYCN locus. The model comprises massive fragmentation of chromosomes and random rejoining of the fragments.

Increase in detectable opportunistic bacteria in the oral cavity of orthodontic patients

OBJECTIVES

This study was performed to detect the opportunistic bacteria and fungi from the oral cavities of orthodontic patients and examine the ability of the organisms to adhere to saliva-coated metallic brackets.

METHODS

Opportunistic bacteria and fungi were isolated from 58 patients (orthodontic group: 42; non-orthodontic group: 16) using culture methods and were identified based on their biochemical and enzymatic profiles. Seven opportunistic and four streptococcal strains were tested for their ability to adhere to saliva-coated metallic brackets.

RESULTS

More opportunistic bacteria and fungi were detected in the orthodontic group than in the non-orthodontic group (P < 0.05). Opportunistic bacteria adhered to saliva-coated metallic brackets to the same degree as oral streptococci.

CONCLUSIONS

The isolation frequencies of opportunistic bacteria and fungi increase during orthodontic treatment, suggesting the importance of paying special attention to oral hygiene in orthodontic patients to prevent periodontal disease and the aggravation of systemic disease in immunocompromised conditions.

Enhancing oral moisture using an extract of Capparis masaikai Levl

The purpose of this study was to examine the effect of a Capparis masaikai Levl. extract on enhancing oral moisture. Solutions of Capparis masaikai extract, citric acid, sodium chloride, and sucrose were dropped on the tongue dorsum of 20 healthy subjects aged 23-34 years. After swallowing each solution, the oral moisture was measured for 60 min using a saliva wetness tester and a moisture checker. The subjects recorded the degree of taste using a visual analog scale to examine the stimulating effect of each solution on salivation. The Capparis masaikai extract had a long-lasting moistening effect on both the tongue dorsum and buccal mucosa for up to 60 min. The weakly bittersweet taste of the extract was perceived stronger than the other taste elements. The results suggest that the Capparis masaikai extract is useful for enhancing oral moisture.

Lafutidine can improve the quality of gastric ulcer healing in humans: a randomized, controlled, multicenter trial

Improving the quality of ulcer healing (QOUH) is one of the valid methods of prevention of relapse of gastric ulcers. We investigated the effect of lafutidine on the QOUH of gastric ulcer compared with famotidine in a randomized, multi-centre controlled trial. Consecutive 80 patients with a gastric ulcer were randomly assigned to receive twice daily either lafutidine (10 mg) or famotidine (20 mg) for 12 weeks. Esophagogastroduodenoscopy was performed to examine the ulcer healing rate and rate of flat type ulcer scars using dye-contrast. The gastric ulcer healing rate was 92.1% in the lafutidine group (35/38) and 94.7% in the famotidine group (36/38). The rate of flat-type ulcer scars was significantly higher in the lafutidine group (68.4%, 26/38) than in the famotidine group (42.1%, 16/38) (P = 0.021). In conclusion, the present study demonstrated that lafutidine, as compared to famotidine, yields a significantly superior QOUH in patients with gastric ulcers in the clinical setting.

[Malignant solitary fibrous tumor of the pleura; report of a case]

A 68-year-old female was admitted to our hospital for further examination of abnormal shadow on chest X-ray. Needle biopsy could not establish pathological diagnosis. Three years later, chest computed tomography (CT) revealed the tumor was enlarged. We suspected it was a malignant tumor, and resected by video-assisted thoracoscopy. The tumor occurred from the right middle lobe, and intraoperative diagnosis was malignant tumor. We added middle lobectomy. Histological examination revealed that tumor was malignant solitary fibrous tumor.

Famotidine vs. omeprazole: a prospective randomized multicentre trial to determine efficacy in non-erosive gastro-oesophageal reflux disease

BACKGROUND

Several studies in Western countries showed that proton-pump inhibitors are superior to histamine2-receptor antagonists or placebo in the treatment of non-erosive gastro-oesophageal reflux disease. The efficacy of acid-suppressive drugs for non-erosive gastro-oesophageal reflux disease in Japan, in which the prevalence of Helicobacter pylori infection is higher compared with Western countries, is unknown.

AIM

To compare the efficacy of famotidine and omeprazole in Japanese patients with non-erosive gastro-oesophageal reflux disease by a prospective randomized multicentre trial.

METHODS

A total of 98 patients received either famotidine 20 mg b.d. (n = 48) or omeprazole once daily (n = 50). Frequency of gastro-oesophageal reflux disease symptoms and health-related quality of life were evaluated at baseline and after 4 weeks of treatment. Complete relief was defined as no gastro-oesophageal reflux disease symptoms during the 7-day interval in week 4.

RESULTS

Complete relief was achieved in 23 (48%) of patients receiving famotidine and 28 (56%) of patients treated with omeprazole. In the famotidine group, complete relief rate in H. pylori-negative patients was significantly lower than H. pylori-positive patients (35% vs. 64%). Both famotidine and omeprazole improved most scales of health-related quality of life. Omeprazole significantly improved reflux score irrespective of H. pylori infection while famotidine significantly improved reflux score in H. pylori-positive patients but not in H. pylori-negative patients.

CONCLUSIONS

Omeprazole is more effective than famotidine for the control of gastro-oesophageal reflux disease symptoms in H. pylori-negative patients, while similar efficacy is observed in H. pylori-positive patients with non-erosive gastro-oesophageal reflux disease.

Effects of ranitidine on quality of gastric ulcer healing compared with famotidine: a randomized, controlled, multicenter trial

Ranitidine has been found to have anti-inflammatory action as well as antisecretory action in experimental models. However, there are no reports in human gastric ulcer. The aim of this study was to investigate the effects of ranitidine compared with those of famotidine on the quality of gastric ulcer healing. We randomly assigned 69 consecutive patients with gastric ulcers to ranitidine (n = 34) or famotidine (n = 35) for 12 weeks, with endoscopic assessment of the quality of gastric ulcer healing and histological assessment of gastric mucosa 12 weeks after treatment started. Ulcer healing rates of over 95% were very similar in the two groups. The rates of ulcer scars with a flat pattern (good-quality healing) were significantly higher in the ranitidine group than in the famotidine group (per protocol, 63.0% and 34.5%, p = 0.033). The neutrophil infiltration score in the body mucosa treated with famotidine, but not ranitidine, significantly increased after treatment. In contrast, the mononuclear cell infiltration score in the antral mucosa treated with ranitidine, but not in that treated with famotidine, had significantly decreased. In conclusion, initial therapy with ranitidine significantly improved the quality of gastric ulcer healing and the histological scores of gastric mucosa compared with famotidine.

[Sentinel node biopsy for staging of small peripheral lung cancer]

Is it possible to choose between limited lymph node sampling and systematic lymphadenectomy from the distribution of sentinel lymph nodes in patients with small lung cancer less than 2 cm in diameter?

METHODS

Twenty-four patients with cN0M0 lung cancer less than 2 cm in diameter were enrolled. A radioisotope tracer (Tc-99 m tin colloid or phyphate) was injected in the vicinity of the tumor before surgery under computed tomography (CT) guidance. The radioactivity of each resected lymph node was measured separately with a hand-held gamma probe after complete tumor resection. Sentinel nodes were identified and the accuracy of sentinel node mapping was examined.

RESULTS

Successful radionuclide migration occurred in 20 of the 24 patients (83.3%). There were 21 N0 patients and 3 N-positive patients. There was no false-negative case, so the sensitivity and the specificity was 100%. The lobar lymph nodes were identified as sentinel nodes more frequently than other lymph nodes.

CONCLUSION

The sentinel node concept is valid in patients with small lung cancer less than 2 cm in diameter. We believe that, if sentinel nodes are identified, sentinel node mapping can allow the accurate intraoperative diagnosis of pathological N0 status in patients with small peripheral lung cancer.

Chromosomal assignments of mammalian genes with an acute inflammation-regulated expression in liver

A set of acute inflammation-regulated genes expressed in liver has been assigned to rat, mouse, and human chromosomes by detecting species-specific PCR amplicons in rat(x)mouse or mouse(x)hamster somatic cell hybrids or radiation hybrids or by in silico matches of corresponding rat cDNAs to various libraries of previously assigned rat, mouse, or human genes or expressed-sequence tags. This allowed us to assign 24, 22, and 21 inflammation-regulated genes to rat, mouse, and human chromosomes, respectively. From these assignments as well as those previously determined for a larger set of genes with an acute inflammation-regulated transcription in liver, we further investigated whether such genes are clustered onto given chromosomes. A cluster was found on rat Chromosome (Chr) 6q with a conserved synteny on mouse Chr 12 and human Chr 14q13-q32, and another cluster previously reported on human Chr 1q has been extended with five further genes. Our data suggest that during an acute inflammation, a higher-order regulation may control some liver-expressed genes that share a given chromosome area.

Molecular and phenotypic analysis of Attractin mutant mice

Mutations of the mouse Attractin (Atrn; formerly mahogany) gene were originally recognized because they suppress Agouti pigment type switching. More recently, effects independent of Agouti have been recognized: mice homozygous for the Atrn(mg-3J) allele are resistant to diet-induced obesity and also develop abnormal myelination and vacuolation in the central nervous system. To better understand the pathophysiology and relationship of these pleiotropic effects, we further characterized the molecular abnormalities responsible for two additional Atrn alleles, Atrn(mg) and Atrn(mg-L), and examined in parallel the phenotypes of homozygous and compound heterozygous animals. We find that the three alleles have similar effects on pigmentation and neurodegeneration, with a relative severity of Atrn(mg-3J) > Atrn(mg) > Atrn(mg-L), which also corresponds to the effects of the three alleles on levels of normal Atrn mRNA. Animals homozygous for Atrn(mg-3J) or Atrn(mg), but not Atrn(mg-L), show reduced body weight, reduced adiposity, and increased locomotor activity, all in the presence of normal food intake. These results confirm that the mechanism responsible for the neuropathological alteration is a loss--rather than gain--of function, indicate that abnormal body weight in Atrn mutant mice is caused by a central process leading to increased energy expenditure, and demonstrate that pigmentation is more sensitive to levels of Atrn mRNA than are nonpigmentary phenotypes.

Serological properties of Abiotrophia and Granulicatella species (nutritionally variant streptococci)

Serological variations were examined among 12 type or reference strains and 91 oral isolates of vitamin B6-dependent Abiotrophia and Granulicatella spp. Rabbits were immunized with whole cells of 12 selected strains and 10 typing antisera were obtained, which were unreactive with the Lancefield group A to G antigen preparations. The reactivity of the antisera and autoclaved cell surface antigen extracts was tested by double diffusion in agar gel and a capillary precipitin test. These typing antisera categorized all Abiotrophia defectiva strains, all except one Granulicatella elegans strain, three-quarters of the Granulicatella adiacens, and half of the Granulicatella paraadiacens into 8 serotypes and 2 subserotypes. The Granulicatella balaenopterae type strain was unserotypable. All A. defectiva strains were serotype I, some of which were divided into subserotype I-1 and/or I-5. The G. adiacens strains generally belonged to serotype II or III, and the G. paraadiacens strains to serotype IV, V or VI. All G. adiacens or G. paraadiacens serotype II strains were also subserotype I-5. The G. elegans strains were serotype VII or VIII. These Abiotrophia and Granulicatella serotypes were undetectable among 33 strains of the other 11 species including the bacteriolytic enzyme-producing but vitamin B6-independent strains of Streptococcus, Enterococcus, Dolosigranulum and Aerococcus. The proposed serotyping system for Abiotrophia and Granulicatella spp. would be helpful in the identification and classification of these unique coccal isolates in ecological and epidemiological studies.

Detection of rice panicle blast with multispectral radiometer and the potential of using airborne multispectral scanners

ABSTRACT Rice reflectance was measured to determine the spectral regions most sensitive to panicle blast infection. Reflectance increased in the 430- to 530-, 580- to 680-, and 1,480- to 2,000-nm regions at the dough stage both in the laboratory and the field as the percentage of diseased spikelets increased. The wavebands of the greatest sensitivity were in the visible region, located near 485 and 675 nm. After the yellow-ripe growth stage, near-infrared rather than visible reflectance responded to panicle blast infections. Ratios of rice reflectance were evaluated as indicators of panicle blast. R470/R570 (reflectance at 470 nm divided by reflectance at 570 nm), R520/R675, and R570/R675 decreased significantly as the incidence of panicle blast increased at the dough stage. At the yellow-ripe stage, R550/R970 and R725/R900 were used to estimate panicle blast severity as measured in terms of the percentage of diseased spikelets. According to the simulation that uses ground-based sensor data, airborne multispectral scanners may be effective in detecting the occurrence of panicle blast using a band combination of 530- to 570- and 650- to 700-nm regions at the dough stage.

Pho85 kinase, a yeast cyclin-dependent kinase, regulates the expression of UGP1 encoding UDP-glucose pyrophosphorylase

The PHO85 gene is a negative regulator of the PHO system in the yeast Saccharomyces cerevisiae and encodes a protein kinase (Pho85) highly homologous to the Cdc28 kinase (Cdc28). Ten cyclin-like proteins are known to interact with Pho85, and combination with different cyclins is believed to be responsible for distinct Pho85 functions, including phosphate metabolism, carbon source utilization and cell cycle regulation. However, only a limited number of substrates of Pho85 kinase, including Pho4, Gsy2 and Sicl, have so far been identified. To search for more targets of Pho85 and to clarify the genetic control mechanisms by Pho85 kinase in these cellular functions, we carried out a genome-wide analysis of the effect of a pho85Delta mutation on gene expression. We found that expression of various genes involved in carbon metabolism are affected by the mutation and that among them, UGP1 promoter activity was increased in the absence of Pho85 kinase. This increase in the promoter activity was not observed in a pho4Delta mutant or with a mutant UGP1 promoter that is devoid of putative Pho4 and Bas2 binding sites, suggesting that UGP1 expression is modulated by Pho85 through Pho4. We also found that expression of several Pho85-cyclin genes were altered by the carbon source, the growth phase and Pho85 kinase itself.

Attractin/mahogany/zitter plays a critical role in myelination of the central nervous system

The rat zitter (zi) mutation induces hypomyelination and vacuolation in the central nervous system (CNS), which result in early-onset tremor and progressive flaccid paresis. By positional cloning, we found a marked decrease in Attractin (Atrn) mRNA in the brain of the zi/zi rat and identified zi as an 8-bp deletion at a splice donor site of Atrn. Atrn has been known to play multiple roles in regulating physiological processes that are involved in monocyte-T cell interaction, agouti-related hair pigmentation, and control of energy homeostasis. Rat Atrn gene encoded two isoforms, a secreted and a membrane form, as a result of alternative splicing. The zi mutation at the Atrn locus darkened coat color when introduced into agouti rats, as also described in mahogany (mg) mice, carrying the homozygous mutation at the Atrn locus. Transgenic rescue experiments showed that the membrane-type Atrn complemented both neurological alteration and abnormal pigmentation in zi/zi rats, but that the secreted-type Atrn complemented neither mutant phenotype. Furthermore, we discovered that mg mice exhibited hypomyelination and vacuolation in the CNS associated with body tremor. We conclude from these results that the membrane Atrn has a critical role in normal myelination in the CNS and would provide insights into the physiology of myelination as well as the etiology of myelin diseases.

Biological leaching of heavy metals from anaerobically digested sewage sludge using indigenous sulfur-oxidizing bacteria and sulfur waste in a closed system

The utilization of indigenous sulfur-oxidizing bacteria and sulfur waste was investigated in order to remove heavy metals from anaerobically digested sewage sludge economically. Indigenous sulfur-oxidizing bacteria existing in anaerobically digested sewage sludge were activated by adding elemental sulfur to the sludge and then the bacteria were isolated. It was found that indigenous sulfur-oxidizing bacteria could utilize sulfur waste generated by desulfurization of digestion gas as a substrate. Then, biological leaching of heavy metals from anaerobically digested sewage sludge was carried out using indigenous sulfur-oxidizing bacteria and sulfur waste. By adding sulfur waste to sewage sludge, sulfuric acid was produced by the bacteria and the sludge pH decreased. Heavy metals in sewage sludge were effectively removed owing to the decrease of pH. The optimum amount of sulfur waste added to decrease the pH sufficiently was 5g/L when the sludge concentration was 2%. It was presented that the biological leaching of heavy metals from sewage sludge can be carried out in a closed system, where all required materials are obtained in a sewage treatment plant.

Characterization of the yeast Cdc7p/Dbf4p complex purified from insect cells. Its protein kinase activity is regulated by Rad53p

The yeast Saccharomyces cerevisiae Cdc7p/Dbf4p protein kinase complex was purified to near homogeneity from insect cells. The complex efficiently phosphorylated yeast Mcm2p and less efficiently the remaining Mcm proteins or other replication proteins. Significantly, when pretreated with alkaline phosphatase, Mcm2p became completely inactive as a substrate, suggesting that it must be phosphorylated by other protein kinase(s) to be a substrate for the Cdc7p/Dbf4p complex. Mutant Cdc7p/Dbf4p complexes containing either Cdc7-1p or Dbf4-1 approximately 5p were also partially purified from insect cells and characterized in vitro. Furthermore, the autonomously replicating sequence binding activity of various dbf4 mutants was also analyzed. These studies suggest that the autonomously replicating sequence-binding and Cdc7p protein kinase activation domains of Dbf4p collaborate to form an active Cdc7p/Dbf4p complex and function during S phase in S. cerevisiae. It is shown that Rad53p phosphorylates the Cdc7p/Dbf4p complex in vitro and that this phosphorylation greatly inhibits the kinase activity of Cdc7p/Dbf4p. This result suggests that Rad53p controls the initiation of chromosomal DNA replication by regulating the protein kinase activity associated with the Cdc7p/Dbf4p complex.

Up-regulation of genes encoding glycosylphosphatidylinositol (GPI)-attached proteins in response to cell wall damage caused by disruption of FKS1 in Saccharomyces cerevisiae

FKS1 and FKS2 encode alternative catalytic subunits of the glucan synthases that are responsible for synthesis of beta-1,3-glucan in the Saccharomyces cerevisiae cell wall. Disruption of FKS1 reduces the glucan content of the cell wall, increases chitin content and activates the expression of CWP1, which encodes a glycosylphosphatidylinositol (GPI)-dependent cell wall protein. These cellular responses have been regarded as compensating for cell wall damage in order to maintain cell wall integrity. Here, we report the identification, by genome-wide screening, of 22 genes that are transcriptionally up-regulated in fks1delta cells. Among them, five genes were found to encode GPI-attached proteins, three of which are covalently associated with the cell wall. Deletion and replacement analysis of the promoter regions identified Rlm1-binding sequences as being responsible for the up-regulation following disruption of FKS1. Using the rlm1delta tetOp-FKS1 strain, in which the expression of FKS1 can be repressed by doxycycline, we examined the requirement for Rlm1 for the transcriptional up-regulation of these five genes. Three of the five genes were not up-regulated by doxycycline, indicating that Rlm1 mediates their up-regulation when FKS1 is inactivated. The remaining two genes were up-regulated by doxycycline, suggesting that a transcription factor other than Rlm1 is involved in their response to disruption of FKS1.

Chromosomal mapping of genes for epilepsy in NER: a rat strain with tonic-clonic seizures

PURPOSE

NER is a mutant rat strain that exhibits spontaneous tonic-clonic convulsions accompanied by epileptic discharges on ictal EEG and serves as a model for generalized tonic-clonic seizures in humans. Our previous experiments have suggested that a major autosomal recessive gene and several minor genes regulate the inheritance of tonic-clonic seizures in NER. The purpose of this study was to confirm the mode of inheritance and to locate the causative genes for epilepsy in NER on the rat genetic map.

METHODS

We developed F1 hybrid (F1) and reciprocal back-cross progenies of NER with a seizure-resistant strain, F344, and evaluated their seizure susceptibility under tossing-stimulated and nonstimulated conditions. Backcross animals were genotyped using simple sequence length polymorphism markers for polymerase chain reactions. Linkage between seizure susceptibility and marker loci was analyzed by chi2 statistic tests and by the computer programs MAPMAKER/EXP and MAPMAKER/QTL.

RESULTS

Under tossing-stimulating conditions, tonic-clonic seizures were provoked in 90% of NER and 66% of (F1 x NER) backcross animals, but no seizures occurred in the F344, F1, or (F1 x F344) backcross animals. Routine monitoring of nonstimulated animals revealed spontaneous tonic-clonic convulsions in 100% of NER and 64.2% of (F1 x NER) backcross animals, but no seizures in F344 or F1. Gender effect on seizure susceptibility was negligible in (F1 x NER) backcross in both conditions. Preliminary genome-wide scanning and subsequent precise location of the causative genes revealed seizure susceptibility loci, designated Ner1 and Ner2, on rat chromosomes 1 and 3, respectively.

CONCLUSIONS

Ner1 is a locus that controls the inheritance of spontaneous tonic-clonic seizures in an autosomal recessive mode, whereas Ner2 affects the occurrence of tossing-induced seizures. Orthologous genes in the vicinity of these loci may be related to epileptogenesis in other species, including humans.

Accumulation of N-acetyl-L-aspartate in the brain of the tremor rat, a mutant exhibiting absence-like seizure and spongiform degeneration in the central nervous system

The tremor rat is a mutant that exhibits absence-like seizure and spongiform degeneration in the CNS. By positional cloning, a genomic deletion was found within the critical region in which the aspartoacylase gene is located. Accordingly, no aspartoacylase expression was detected in any of the tissues examined, and abnormal accumulation of N-acetyl-L-aspartate (NAA) was shown in the mutant brain, in correlation with the severity of the vacuole formation. Therefore, the tremor rat may be regarded as a suitable animal model of human Canavan disease, characterized by spongy leukodystrophy that is caused by aspartoacylase deficiency. Interestingly, direct injection of NAA into normal rat cerebroventricle induced 4- to 10-Hz polyspikes or spikewave-like complexes in cortical and hippocampal EEG, concomitantly with behavior characterized by sudden immobility and staring. These results suggested that accumulated NAA in the CNS would induce neuroexcitation and neurodegeneration directly or indirectly.

Epileptic seizures induced by N-acetyl-L-aspartate in rats: in vivo and in vitro studies

Tremor rat (tm/tm), the parent strain of spontaneously epileptic rat (SER: zi/zi, tm/tm), exhibits absence-like seizures characterized by 5-7 Hz spike-wave-like complexes on cortical and hippocampal electroencephalograms (EEG) after 10 weeks of age, prior to development of convulsive seizures. Recently, this animal model has been demonstrated to display a genomic microdeletion within the critical region of tm, where aspartoacylase hydrolyzing N-acetyl-L aspartate (NAA) is located, besides showing the ability to accumulate NAA in the brain. Therefore, the present study was performed to determine the involvement of NAA in the induction of epileptic seizures. When NAA (4 micromol) was applied intracerebroventricularly (i.c.v.) to normal Wistar rats, 4-10 Hz polyspikes and/or spike-wave-like complexes followed by absence-like seizure before persistent 1-5 Hz waxing high-voltage after-discharges were observed on cortical and hippocampal EEG. At a higher dose (8 micromol), NAA induced convulsive seizures. The absence-like seizures with polyspikes and/or spike-wave-like complexes on the EEG were also observed with i.c.v. NAA in premature tremor rats without seizures. The NAA-induced seizures in normal rats were antagonized by i.c.v. glutamic acid diethyl ester, a non-selective glutamate receptor antagonist. In addition, NAA applied to the bath rapidly induced a long-lasting depolarization concomitantly with repetitive firings in hippocampal CA3 neurons of normal rat brain slice preparations. These findings suggest that NAA is involved in the induction of absence-like seizures and/or convulsion, probably via glutamate receptors.

An integrated rat genome map based on genetic and cytogenetic data

In this study we combined three major rat genome maps, by adding 66 markers to the Kyoto Laboratory Animal Science map (KLAS map), and constructed an integrated map. The resultant integrated map consists of 5,682 redundant markers, spanning a genetic length of 2,028 cM. Eighty genetic markers were anchored to the cytogenetic map, fixing all the genetic maps in the physically correct orientation. This map encapsulates the progress in rat mapping studies in past years and offers useful information for QTL analysis. The map figures are available at http:/(/)www.anim.med.kyoto-u.ac.jp/.

Endocardiac infectivity and binding to extracellular matrix proteins of oral Abiotrophia species

Microorganisms of the genus Abiotrophia, formerly known as nutritionally variant streptococci, are members of the oral flora and often isolated from patients with endocarditis, but pathogenicity of oral Abiotrophia species has not been examined yet. In this study, 17 strains isolated from healthy human oral cavities and 7 reference strains (all derived from patients with endocarditis) of Abiotrophia spp. were tested for their abilities to cause infections in damaged heart tissues in catheterized rats and to adhere to extracellular matrix proteins in vitro. The reference strains of A. defectiva and A. adiacens showed high infectivities in the rats. Four oral isolates of these two species showed similarly high infectivities and three had moderate infectivities. Most of 10 oral strains of A. para-adiacens and A. elegans were found to be generally less infective. The highly infective A. adiacens strains showed markedly high fibronectin-binding capacity, suggesting a possible relationship between the fibronectin-binding capacity and damaged heart tissue infectivity of the Abiotrophia species. A. defectiva strains which were also highly infective had moderate levels of binding to fibronectin and other extracellular matrix proteins. Most of A. para-adiacens and A. elegans strains showed low or negligible binding capacities to any extracellular matrix proteins tested.

Genetic mapping of the rat mutation creeping and evaluation of its positional candidate gene reelin

We have previously described a rat autosomal recessive mutation, creeping (cre), causing severe ataxia and disarrangement of neuronal cells in the central nervous system. The mutant strain has recently been successfully inbred, named Komeda Zucker creeping (KZC) rat. In the present study, we have performed a genetic analysis of the creeping mutation, and mapped it to rat Chromosome (Chr) 4. Comparative mapping, together with the similarity of the phenotype, suggested that the creeping mutation is homologous to the mouse reeler mutation. In fact, reelin expression was markedly reduced in the homozygous mutant (cre/cre) animals compared with the normal littermates. Thus, the KZC rat should become a useful biological model with a novel mutation in the reelin gene.

Mapping of four simple sequence repeat (SSR) markers on rat chromosome 4

We previously reported that several markers on rat chromosome (Chr) 4 cosegregated with the occurrence of cerebral stroke and brain edema in stroke-prone spontaneously hypertensive rats (SHRSP). To obtain insights into the positional candidate genes for stroke susceptibility in this region, we mapped four genes, Taurine transporter (Tau), tumor necrosis factor receptor (Tnfr), GABA transporter (Gat1) and glucose transporter-3 (Glut3) genes, using newly developed simple sequence repeat (SSR) markers on rat Chr 4. We isolated the SSRs for the genes either by screening a rat genomic library or by searching the GenBank database. By linkage analysis using two sets of backcrosses, Gat1 and Tnfr were mapped in the region associated with stroke, while Taut was located distant from the region. The Glut3 locus was also assigned to rat Chr 4 using a rat x mouse hybrid clone panel. These results indicated that the Tnfr, Gat1 and Glut3 genes were good positional candidates for the stroke susceptibility in SHRSP, suggesting that further evaluation of these genes by functional studies could prove useful.

Thioredoxin inhibits tumor necrosis factor- or interleukin-1-induced NF-kappaB activation at a level upstream of NF-kappaB-inducing kinase

Gene induction by tumor necrosis factor-alpha (TNFalpha) or interleukin-1beta (IL-1beta) is mediated in part by activation of the transcription factor nuclear factor kappaB (NF-kappaB), and requires signal adaptor molecules such as TNF receptor-associated factor (TRAFs). The latter interact with the NF-kappaB-inducing kinase (NIK), which is believed to be part of the IkappaB kinase complex. Although the precise mechanism is to be elucidated, it is well-known that antioxidant treatments inhibit the inflammatory cytokine-induced NF-kappaB activation. Thioredoxin (TRX) is a 12-kDa endogenous protein that regulates various cellular functions by modulating the redox state of proteins, overexpression of this molecule inhibits NF-kappaB activation. To elucidate the roles of TRX in the signal transduction of the cytokines, we investigated the effects of TRX on NF-kappaB activation induced by cytokine treatment or by overexpression of the signaling molecules. Our data show that TRX treatment inhibits NF-kappaB-dependent transcription at the level of downstream of TRAFs and upstream of NIK: TRX inhibited TRAF2-, TRAF5-, and TRAF6-induced NF-kappaB activation but does not inhibit NIK-, IKKalpha-, and MEKK-induced activation. In addition, we show that TRX inhibits NF-kappaB activation in a manner different from that for SAPK (stress activated protein kinase) inhibition.

Amino acid residues in the omega-minus region participate in cellular localization of yeast glycosylphosphatidylinositol-attached proteins

The final destination of glycosylphosphatidylinositol (GPI)-attached proteins in Saccharomyces cerevisiae is the plasma membrane or the cell wall. Two kinds of signals have been proposed for their cellular localization: (i) the specific amino acid residues V, I, or L at the site 4 or 5 amino acids upstream of the GPI attachment site (the omega site) and Y or N at the site 2 amino acids upstream of the omega site for cell wall localization and (ii) dibasic residues in the region upstream of the omega site (the omega-minus region) for plasma membrane localization. The relationships between these amino acid residues and efficiencies of cell wall incorporation were examined by constructing fusion reporter proteins from open reading frames encoding putative GPI-attached proteins. The levels of incorporation were high in the constructs containing the specific amino acid residues and quite low in those containing two basic amino acid residues in the omega-minus region. With constructs that contained neither specific residues nor two basic residues, levels of incorporation were moderate. These correlations clearly suggest that GPI-attached proteins have two different signals which act positively or negatively in cell wall incorporation for their cellular localization.

Alymphoplasia is caused by a point mutation in the mouse gene encoding Nf-kappa b-inducing kinase

The alymphoplasia (aly) mutation of mouse is autosomal recessive and characterized by the systemic absence of lymph nodes (LN) and Peyer's patches (PP) and disorganized splenic and thymic structures with immunodeficiency. Although recent reports have shown that the interaction between lymphotoxin (LT) and the LT beta-receptor (Ltbeta r, encoded by Ltbr) provides a critical signal for LN genesis in mice, the aly locus on chromosome 11 is distinct from those for LT and its receptor. We found that the aly allele carries a point mutation causing an amino acid substitution in the carboxy-terminal interaction domain of Nf-kappa b-inducing kinase (Nik, encoded by the gene Nik). Transgenic complementation with wild-type Nik restored the normal structures of LN, PP, spleen and thymus, and the normal immune response in aly/aly mice. In addition, the aly mutation in a kinase domain-truncated Nik abolished its dominant-negative effect on Nf-kappa b activation induced by an excess of Ltbeta r. Our observations agree with previous reports that Ltbeta r-deficient mice showed defects in LN genesis and that Nik is a common mediator of Nf-kappa b activation by the tumour necrosis factor (TNF) receptor family. Nik is able to interact with members of the TRAF family (Traf1, 2, 3, 5 and 6), suggesting it acts downstream of TRAF-associating receptor signalling pathways, including Tnfr, Cd40, Cd30 and Ltbeta r. The phenotypes of aly/aly mice are more severe than those of Ltbr-/- mice, however, indicating involvement of Nik in signal transduction mediated by other receptors.

Amino acid sequence requirement for efficient incorporation of glycosylphosphatidylinositol-associated proteins into the cell wall of Saccharomyces cerevisiae

During cell wall biogenesis in Saccharomyces cerevisiae, some glycosylphosphatidylinositol (GPI)-attached proteins are detached from GPI moieties and bound to beta-1,6-glucan of the cell wall. The amino acid sequence requirement for the incorporation of GPI-attached proteins into the cell wall was studied by using reporter fusion proteins. Only the short omega-minus region composed of five amino acids, which is located upstream of the omega site for GPI attachment, determined the cellular localization of the GPI-associated proteins. Within the omega-minus region, amino acid residues at the omega-4 or -5 and omega-2 sites were important for the cell wall incorporation. Yap3p, a well characterized GPI-anchored plasma membrane aspartic protease, was localized in the cell wall when the omega-minus region was mutated to sequences containing Val or Ile at the omega-4 or -5 site and Val or Tyr at the omega-2 site.

Alternate activity in the synergistic muscles during prolonged low-level contractions

The purpose of this study was to investigate the functional interrelationship between synergistic muscle activities during low-level fatiguing contractions. Six human subjects performed static and dynamic contractions at an ankle joint angle of 110 degrees plantar flexion and within the range of 90-110 degrees (anatomic position = 90 degrees) under constant load (10% maximal voluntary contraction) for 210 min. Surface electromyogram records from lateral gastrocnemius (LG), medial gastrocnemius (MG), and soleus (Sol) muscles showed high and silent activities alternately in the three muscles and a complementary and alternate activity between muscles in the time course. In the second half of all exercise times, the number of changes in activity increased significantly (P < 0.05) in each muscle. The ratios of active to silent periods of electromyogram activity were significantly higher (P < 0.05) in MG (4.5 +/- 2.2) and Sol (4.3 +/- 2.8) than in the LG (0.4 +/- 0.1), but no significant differences were observed between MG and Sol. These results suggest that the relative activation of synergistic motor pools are not constant during a low-level fatiguing task.

Serotype variation in Streptococcus anginosus, S. constellatus and S. intermedius

Various serotypes reported in three serotyping systems for the 'Streptococcus milleri' group, i.e., Ottens I-IV, Osano I-IV and serotypes a-k, were compared with each other in a capillary precipitation test and by the double immunodiffusion test. Only two of the 19 serotypes, f and Ottens-III, were identical, and the other 17 serotypes were independent. Thus, 18 serotypes and another three candidates (a-, b- and g-cross-reactive) were found in the 'S. milleri' group. Of the 248 strains tested, 197 were serotypable, and 23 strains carried two type antigens. Generally, the Ottens I, II, III (serotype f), IV and Osano IV antigens, often together with the Lancefield group F antigen, were found in S. anginosus and S. constellatus. In addition, the serotype a, c, d, e and k antigens with the group A, C or G antigen were distributed in S. anginosus, the serotype b antigen in S. constellatus and the g, h, i, j, Osano I, II and III antigens in S. intermedius. Twenty-five of the untypable strains were Lancefield groupable (mostly F).

Screening for glycosylphosphatidylinositol (GPI)-dependent cell wall proteins in Saccharomyces cerevisiae

Open reading frames in the genome of Saccharomyces cerevisiae were screened for potential glycosylphosphatidylinositol (GPI)-attached proteins. The identification of putative GPI-attached proteins was based on three criteria: the presence of a GPI-attachment signal sequence, a signal sequence for secretion and a serine- or threonine-rich sequence. In all, 53 ORFs met these three criteria and 38 were further analyzed as follows. The sequence encoding the 40 C-terminal amino acids of each was fused with the structural gene for a reporter protein consisting of a secretion signal, alpha-galactosidase and a hemagglutinin (HA) epitope, and examined for the ability to become incorporated into the cell wall. On this basis, 14 of fusion proteins were classified as GPI-dependent cell wall proteins because cells expressing these fusion proteins: (i) had high levels of alpha-galactosidase activity on their surface; (ii) released significant amounts of the fusion proteins from the membrane on treatment with phosphatidylinositol-specific phospholipase C (PI-PLC); and (iii) released fusion proteins from the cell wall following treatment with laminarinase. Of the 14 identified putative GPI-dependent cell wall proteins, 12 had novel ORFs adjacent to their GPI-attachment signal sequence. Amino acid sequence alignment of the C-terminal sequences of the 12 ORFs, together with those of known cell wall proteins, reveals some sequence similarities among them.

Extension of conserved regions in the rat and mouse genomes by chromosomal assignments of 29 rat genes

We recently constructed a comparative genetic map of the rat, mouse and human genomes based on information obtained from several databases. In this study, we performed chromosomal assignments of 29 rat genes with somatic cell hybrid clones, in order to clarify and extend the conserved regions in the rat and mouse genomes. As a result, the conserved regions were extended by 89 cM. Together with our previous report, the length of the conserved regions in the rat and mouse spans 847 cM on the mouse linkage map, indicating that 53% of the mouse genome is covered by homologous regions in the rat. In addition, four conserved regions were newly revealed. The method described in this study appears to be simple and efficient for constructing a whole genome comparative map of the rat and mouse.

Correlation between genetic and cytogenetic maps of the rat

To correlate rat genetic linkage maps with cytogenetic maps, we localized 25 new cosmid-derived simple sequence length polymorphism (SSLP) markers and 14 existing genetic markers on cytogenetic bands of chromosomes, using fluorescence in situ hybridization (FISH). Next, a total of 58 anchor loci, consisting of the 39 new and 19 previously reported ones, were integrated into the genetic linkage maps. Since most of the new anchor loci were developed to be localized near the terminals of the genetic or cytogenetic maps for each chromosome, the orientation and coverage of the whole genetic linkage maps were determined or confirmed with respect to the cytogenetic maps. Thus, we provide here a new base for rat genetic maps.

A comparative genetic map of rat, mouse and human genomes

The increasing availability of molecular markers and the development of highly efficient gene mapping strategies for the mouse, rat and human genomes have generated vast quantities of information allowing for the progressive refinement of comparative maps. In this publication we report on an updated version of our rat/mouse/human comparative genetic map, based on the mouse map. Databases for mouse, rat and human gene mapping were used for the collection of homologs mapped in the species. The comparative map was constructed with a total of 1,235 mouse loci having known homologs in the rat and/or human: 16 having homologs only in the rat, 884 having only in the human and 335 both in the rat and human. The combined length of the segments conserved between the rat and mouse spans 758 cM on the mouse map. This indicates that about 47% of the mouse genome is now covered by known rat homologous regions. Five novel regions homologous for the rat and mouse were identified. This comparative genetic map should be useful for researchers working on genetic studies in the rat, mouse and human.

A non-MHC locus essential for autoimmune type I diabetes in the Komeda Diabetes-Prone rat

The Long-Evans Tokushima Lean (LETL) rat, characterized by rapid onset of insulin-dependent (type I) diabetes mellitus (IDDM), no sex difference in the incidence of IDDM, autoimmune destruction of pancreatic beta cells, and no significant T cell lymphopenia, is a desirable animal model for human IDDM. We have established a diabetes-prone substrain of the LETL rat, named Komeda Diabetes-Prone (KDP) rat, showing a 100% development of moderate to severe insulitis within 220 d of age. The cumulative frequency of IDDM was 70% at 120 d of age, and reached 82% within 220 d of age. Here, we performed the first genome-wide scan for non-MHC IDDM susceptibility genes in this strain. The analysis of three crosses has led to the revelation of a major IDDM susceptibility gene, termed Iddm/kdp1, on rat chromosome (Chr) 11. Homozygosity for the KDP allele at this locus is shown to be essential for the development of moderate to severe insulitis and the onset of IDDM. Comparative mapping suggests that the homologues of Iddm/ kdp1 are located on human Chr 3 and mouse Chr 16 and would therefore be different from previously reported IDDM susceptibility genes.