Mutations in the WUSCHEL gene of Arabidopsis thaliana result in the development of shoots without juvenile leaves

The vegetative growth of Arabidopsis thaliana can be divided into two phases. The transition from the juvenile (early) phase to the adult (later) phase is associated with changes in several morphological features of leaves, such as the shape of leaf blades, the number of trichomes and patterns of venation. In a screening of mutants with altered morphological identities of leaves, we found one which we named juvenile leafless and misshapen shoot apical meristem (jam). The mutation represented a new allele of the WUSCHEL (WUS) gene, and, in its presence, plants produced no juvenile leaves. Analysis of the morphology of mutant plants revealed that all the rosette leaves had characteristics of adult leaves. The formation of the first rosette leaf in the wus(jam) mutant was markedly delayed, and occurred at the almost same time as formation of the third or fourth leaf in wild-type plants. In the wild-type, these leaves correspond to the first adult leaves. Analysis by RT-PCR showed that transcripts of WUS accumulated in shoot apices and roots, but not in cotyledons and leaves. The present results suggest that the WUS gene controls the morphological traits of rosette leaves either directly or indirectly. In view of the predicted function of the WUS gene, namely maintenance of stem cells within the shoot apical meristem, we suggest that the lack of juvenile leaves in the mutant might have been caused by interruption of leaf initiation during the juvenile phase or by halting of an entire process of formation of juvenile leaves.

Preparation of CM-chitin microspheres by complexation with iron(III) in w/o emulsion and their biodisposition characteristics in mice

6-O-Carboxymethylchitin (CM-chitin) was partially deacetylated by alkaline treatment, and the 30% deacetylated product was named CM-DA30 and used for the preparation of microspheres. An aqueous solution of CM-DA30 was added to hexane containing 1% (w/w) sorbitan sesquioleate and emulsified by stirring and sonication, and iron(III) chloride was added. The formed microspheres (CM-MS) were washed with methanol and lyophilized after addition of polyethylene glycol. The mean particle diameter was less than a few microm, and longer sonication time tended to decrease the mean particle size. Sixty min of sonication enabled the production of CM-MS consisting of only the particles with a diameter of less than several microm. Iron(III) content and recovery of CM-DA30 were not markedly affected by the sonication time. CM-MS was spherical as was observed by scanning electron microscopy. Fluorescein moieties-containing microspheres (CM-MS-FTC) were prepared in the same manner but using fluorescein-isothiocyanate-labeled CM-DA30 (FTC-CM-DA30) instead of CM-DA30. After i.v. injection of CM-MS-FTC, its body distribution and urinary excretion of FTC-CM-DA30 were examined. CM-MS-FTC was located to some extent in the lung for an initial short time (= 1 h), soon cleared from the lung, and was retained for long in the liver and spleen. CM-MS-FTC was quickly eliminated from the blood circulation, and 60% of the dose was excreted into urine at 3 h after injection. From 3 h after injection, the urinary excretion rate markedly decreased, and the total excreted amount was 66% of the dose at 12 h after injection, which was not significantly different from that at 3 h after injection. The present preparation technique permits producing small microspheres of CM-chitin as a drug carrier possibly useful for the liver targeting.

Evaluation of N-succinyl-chitosan as a systemic long-circulating polymer

The water-soluble, low toxic and less biodegradable chitosan derivative N-succinyl-chitosan (Suc-chitosan) was investigated for body distribution and urinary excretion on a long-time scale (24-72 h after i.v. injection) using a fluorescein-labeling technique. Fluorescein isothiocyanate (FITC)-labeled Suc-chitosan (Suc-chitosan-FTC) was characterized for molecular weight, succinylation degree and FTC content. Systemic retention and tissue distribution of Suc-chitosan-FTC were examined after i.v. administration to normal and Sarcoma 180 tumor-bearing mice. Suc-chitosan-FTC was sustained at a high level in the circulation over 72 h; that is, the plasma half-life in normal mice was 100.3 h and that in tumor-bearing mice was 43.0 h, which was longer than those of other long-circulating macromolecules reported to date. As to the tissues except blood circulation, Suc-chitosan-FTC was distributed very little in tissues other than the tumor. Although the total amount of Suc-chitosan-FTC residing in tested tissues decreased gradually, urinary excretion did not increase from 24 h after injection. These observations suggested that Suc-chitosan-FTC may be eliminated by mechanisms other than in the urine or moved to tissues other than those tested. The ratio of tumor accumulation reached a plateau at 48 h after injection, and the accumulation level, approximately 10%, was similar to those observed for other reported long-circulating macromolecules.

Genetic analysis of the signal-sensing region of the histidine protein kinase VirA of Agrobacterium tumefaciens

The membrane-bound sensor protein kinase VirA of Agrobacterium tumefaciens detects plant phenolic substances, which induce expression of vir genes that are essential for the formation of the crown gall tumor. VirA also responds to specific monosaccharides, which enhance vir expression. These sugars are sensed by the periplasmic domain of VirA that includes the region homologous to the chemoreceptor Trg, and the phenolics are thought to be detected by a part of the cytoplasmic linker domain, while the second transmembrane domain (TM2) is reported to be nonessential. To define regions of VirA that are essential for signal sensing, we introduced base-substitution and deletion mutations into coding regions that are conserved among the respective domains of VirA proteins from various Agrobacterium strains, and examined the effects of these mutations on vir induction and tumorigenicity. The results show that the Trg-homologous region in the periplasmic domain is not essential for the enhancement of vir gene expression by sugars. Most mutations in the TM2 domain also failed to influence enhancement by sugars and reduced the level of vir induction, but a mutation in the TM2 region adjacent to the cytoplasmic linker abolished induction of the vir genes. In the linker domain, sites essential for vir induction by phenolics were scattered over the entire region. We propose that a topological feature formed by the linker domain and at least part of the TM2 may be crucial for activation of a membrane-anchored VirA protein. Complementation analysis with two different VirA mutants suggested that intermolecular phosphorylation between VirA molecules occurs in vivo, and that two intact periplasmic regions in a VirA dimer are required for the enhancement of vir induction by sugars.

Frequency and pattern of transposition of the maize transposable element Ds in transgenic rice plants

Two kinds of T-DNA constructs, I-RS/dAc-I-RS and Hm(R)Ds, carrying a non-autonomous transposable element of Ac of maize were introduced into rice plants by Agrobacterium-mediated gene transfer. Six transgenic rice plants identified as containing a single copy of the element were crossed with two transgenic rice plants carrying a gene for Ac transposase under the control of the cauliflower mosaic virus 35S promoter. In F2 progenies, excision of the element was detected by PCR analysis and re-integration of the element was investigated by Southern blot analysis. The frequency of the excision of the element was found to vary from 0 to 70% depending on the crossing combination. The frequency of the number of individual transposition events out of the total number of F2 plants with germinal excision was 44% in one crossing combination and 38% in the other. In the most efficient case, 10 plants with independent transposition were obtained out of the 49 F2 plants tested. Linkage analysis of the empty donor site and the transposed Ds-insertion site in F3 plants demonstrated that one of five Ds-insertion sites was not linked to the empty donor site. The transgenic rice obtained in this study can be used for functional genomics of rice.

Pharmacokinetics of prolonged-release CPT-11-loaded microspheres in rats

CPT-11-containing microspheres composed of poly-D,L-lactic acid or poly (D,L-lactic acid-co-glycolic acid) copolymers were prepared by an oil-in-water evaporation method. The size and shape of the microspheres were examined, and the drug release rates were analyzed from the in vitro release profiles. CPT-11 aqueous solution was intravenously or intraperitoneally injected at 10 mg/kg, and microspheres were intraperitoneally administered at 50 mg eq CPT-11/kg in rats. The microspheres had an average diameter of around 10 microm and their shape was spherical. All the microspheres contained CPT-11 in a lactone form, and their drug contents and release profiles were basically similar to those of previous microspheres. After i.v. injection of CPT-11 solution, the CPT-11 plasma concentration decreased quickly, SN-38 decreased slowly at a much lower level, and SN-38 glucuronide (SN-38G) declined very slowly at a higher level than SN-38. The plasma concentration of CPT-11 reached a maximum at 30 min after i.p. administration of CPT-11 solution. The area under the plasma concentration-time curve (AUC) of CPT-11 after i.p. administration was somewhat lower compared with that after i.v. administration, but the plasma concentration-time profiles of SN-38 and SN-38G were nearly identical between i.v. and i.p. administration. An i.p. administration of the microspheres resulted in gradually increasing or almost constant CPT-11 levels. The levels of SN-38 were also stable during the observation period (4 days) except for the slowest releasing microsphere in which SN-38 was not detected after 24 h following administration. Intraperitoneal administration of any of the microspheres resulted in stable and similar levels of SN-38G after 24 h following administration. When judging from apparent simple pharmacokinetic analysis, an inconsistency was found between the in vitro drug release and the plasma level to a fair extent, but overall the in vivo drug release rate from microspheres was considered parallel to the in vitro one. The microspheres showing a faster release of CPT-11 exhibited higher plasma levels of CPT-11 and SN-38, explaining the previous results that efficacy was better when the in vitro release rate was higher. That the SN-38 level could be attained to a certain extent even at the range of modest or low plasma concentration of CPT-11 in each administration may be related to the non-linear metabolic conversion from CPT-11 to SN-38.

Direct evidence for increased hydroxyl radicals originating from superoxide in the failing myocardium

Experimental and clinical studies have suggested an increased production of reactive oxygen species (ROS) in the failing myocardium. The present study aimed to obtain direct evidence for increased ROS and to determine the contribution of superoxide anion (*O(2)(-)), H(2)O(2), and hydroxy radical (*OH) in failing myocardial tissue. Heart failure was produced in adult mongrel dogs by rapid ventricular pacing at 240 bpm for 4 weeks. To assess the production of ROS directly, freeze-clamped myocardial tissue homogenates were reacted with the nitroxide radical, 4-hydroxy-2,2,6, 6,-tetramethyl-piperidine-N-oxyl, and its spin signals were detected by electron spin resonance spectroscopy. The rate of electron spin resonance signal decay, proportional to *OH level, was significantly increased in heart failure, which was inhibited by the addition of dimethylthiourea (*OH scavenger) into the reaction mixture. Increased *OH in the failing heart was abolished to the same extent in the presence of desferrioxamine (iron chelator), catalase (H(2)O(2) scavenger), and 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron; LaMotte) (*O(2)(-) scavenger), indicating that *OH originated from H(2)O(2) and *O(2)(-). Further, *O(2)(-) produced in normal myocardium in the presence of antimycin A (mitochondrial complex III inhibitor) could reproduce the increase of H(2)O(2) and *OH seen in the failing tissue. There was a significant positive relation between myocardial ROS level and left ventricular contractile dysfunction. In conclusion, in the failing myocardium, *OH was produced as a reactive product of *O(2)(-) and H(2)O(2), which might play an important role in left ventricular failure.

Bioavailability of amprolium in fasting and nonfasting chickens after intravenous and oral administration

The bioavailability of amprolium (APL) was measured after intravenous (i.v.) and oral (p.o.) administration to chickens. Twelve healthy chickens weighing 1.28-1.41 kg received a dose of 13 mg APL/kg intravenously, and 13 or 26 mg APL/kg orally in both a fasted and a nonfasted condition in a Latin square design. Plasma samples were taken from the subwing vein for determination of APL concentration by HPLC method. The data following intravenous and oral administration were best fitted by 2-compartment and 1-compartment models, respectively, using weighted nonlinear least squares regression. The half-life beta t(1/2)beta, volume of distribution (Vd) and total body clearance (Cl) after intravenous administration were 0.21 h, 0.12 L/kg and 1.32 L/h.kg, respectively. The elimination half-life (t(1/2) Kel) after oral administration was 0.292-0.654 h which is 1.5-3.2 times longer than after intravenous administration, suggesting the presence of a 'flip-flop' phenomenon in chickens. The maximum plasma concentration (Cmax) of 13 mg/kg APL administered orally to chickens during fasting was significantly (about four times) higher than that during nonfasting (P < 0.05). Bioavailability during nonfasting was from 2.3 to 2.6%, and 6.4% during fasting.

Resuscitation from fulminant myocarditis associated with refractory ventricular fibrillation

Resuscitation was possible in a case of fulminant myocarditis with refractory ventricular fibrillation (Vf) using a percutaneous cardiopulmonary support system (PCPS). A 46-year old Japanese man suddenly experienced cardiopulmonary dysfunction shortly after the onset of flu symptoms, was promptly diagnosed as having fulminant myocarditis and PCPS was immediately initiated. On the second day in the hospital, refractory Vf occurred, which lasted for approximately 2h despite repeated efforts to terminate it. Finally, a large dose of steroids was administered. From the third day of hospitalization and onwards, the Vf disappeared totally. The patient completely recovered from such a serious state in 6 months. During the following 3 years, he has had no clinical symptoms of worsening. As in this case demonstrates, most myocarditis is curable and invasive measures are very helpful in rescuing patients from the fulminant type with refractory Vf.

Structure and function of a novel coliphage-associated sialidase

A coliphage named 63D, isolated previously, associated sialidase as a component of phage particles. In order to localize the enzyme in phage particles, phages were partially destroyed by sonication, and the disrupted particles were size fractionated using a sucrose density gradient. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, enzyme assay and electron micrography of the fractions revealed the enzyme to be composed of four identical subunits with a molecular mass of 90 kDa, and the subunits were cross-linked by disulfide bonds. Electron micrographic observation indicated that six enzyme molecules were localized in a phage tail plate as a hexagonal array.

Mucoadhesive suppositories of ramosetron hydrochloride utilizing Carbopol

Suppositories are the preferable dosage form for patients at home or experiencing nausea. Serotonin (5-HT(3))-receptor antagonists are used to treat vomiting in intravenous or oral administration but not suppository form. Ramosetron hydrochloride (RAM) is a new 5-HT(3) antagonist which effectively inhibits vomiting, and we prepared RAM suppositories using Witepsol((R)) H-15 (H-15) containing Carbopol((R)) 934P (CP). The viscosity of suppository base and RAM release properties from suppositories were examined. Plasma RAM concentrations after administration of suppositories to rabbits were estimated and irritation of rectal tissues were observed. Antiemetic effects of suppositories were studied using ferrets. The base viscosity increased with addition of CP. Suppositories containing CP exhibited better absorption in rabbits compared to H-15 suppositories, correlated with release behavior. Suppositories containing 2% CP had 2.5 times larger AUC(0-24 h) than H-15 suppositories, and the MRT was prolonged by 5.8 h compared with i.v. administration. 10% CP suppositories administered to rabbits for 5 days did not irritate the tissues. Antiemetic studies indicated that 2% CP suppository of RAM might have the same effect as i.v. administration. These results suggest that RAM suppositories containing CP are safe and useful in once-a-day dosage form for treatment of chemotherapy-induced nausea.

Molecular cloning and characterization of a novel bacteriophage-associated sialidase

Bacteriophage 63D, previously isolated from sewage, is associated with alpha-2,8-linked polysialic acid degrading activity. We cloned a DNA fragment containing the sialidase gene from a 63D phage genomic library and the enzyme was functionally expressed in Escherichia coli. Determination of the nucleotide sequence of the fragment revealed that it contained one open reading frame (ORF) coding for a 108-kDa polypeptide consisting of 984 amino acid residues. The fragment had promoter sequences similar to the E. coli consensus promoters for sigma70. The deduced amino acid sequence of the central region of the ORF showed homology to those of phages K1F (51.6% identity) and PK1E (51.7% identity) endosialidases. Two Asp-box motifs that are widely found in sialidases were conserved. Purification of the soluble enzyme from lysed culture broth of infected E. coli yielded a 90-kDa protein upon SDS polyacrylamide gel electrophoresis, suggesting that the primary translational product is processed to the mature 90-kDa protein. The molecular mass of the enzyme was determined as 360 kDa by gel filtration, indicating that the native enzyme was probably a tetramer of identical 90-kDa subunits.

The MAP kinase cascade that includes MAPKKK-related protein kinase NPK1 controls a mitotic proces in plant cells

The tobacco NPK1 cDNA was the first-isolated plant cDNA for a homolog of mitogen-activated protein kinase kinase kinases (MAPKKKs). The kinase domain of the NPK1 protein can replace the functions of MAPKKKs in yeasts, while the amino acid sequence of the kinase-unrelated region does not have any homology to those of MAPKKKs from other organisms. Transcription of the NPK1 gene takes place in meristematic tissues or immature organs in a tobacco plant. During a tobacco cell cycle, transcriptional and translational products of NPK1 are present from S to M phase and decrease after the M phase. Expression of the NACK1 gene, which is predicted to encode a novel kinesin-like microtubule-based motor protein capable of activating NPK1, is specific to M phase, suggesting that activation of NPK1 occurs in M phase. Characterization of cDNAs for a MAPKK and a MAPK which can act downstream of NPK1 makes a proposition that the MAP kinase pathway involving NPK1 regulates a mitotic process associated with microtubules.

Sporadic amyotrophic lateral sclerosis with multiple system degeneration: a report of an autopsy case without respirator administration

This report concerns an autopsy case of amyotrophic lateral sclerosis (ALS) with unusual clinical and neuropathological findings. The patient was a Japanese man without hereditary burden who was 49 years old at the time of death. His clinical manifestation included dysarthria at age 48, followed by dysphagia, atrophy and fasciculation of the tongue, muscle weakness in the four extremities, tremor, rigidity, increased deep tendon reflexes in the upper and lower extremities, and incoordination of the four extremities. He died of respiratory failure 12 months after the disease onset. No respirator administration was performed throughout the clinical course. The neuropathological examination revealed not only degeneration of upper and lower motor neuron systems, including the presence of Bunina bodies and ubiquitin-immunoreactive neuronal inclusions in the lower motor neurons, but also prominent degeneration of the substantia nigra and dentate nucleus with slight neuronal loss in the locus ceruleus and pontine nucleus. To our knowledge, this is the first reported case of sporadic ALS without dementia and respirator support, showing degeneration of the substantia nigra and dentate nucleus. This report may contribute to the resolution of the question concerning the neuropathological heterogeneity of sporadic ALS with respiratory support.

The fusion of three primary incisors: report of case

The occurrence of a fusion of three primary incisors is rare. A two-year-old Japanese girl was brought to the pediatric dental outpatient clinic, Tokyo Dental College, to receive a caries-prevention treatment. The fused tooth consisted of the maxillary primary central incisors and right maxillary lateral incisor. Primary left lateral incisor erupted normally and the other primary teeth were erupted. The radicular pulp chambers were fused into one for three fourths of the length from the apex, and only one root. The hair and skin of the patient appeared normal and no systemic abnormality or congenital disease was noted in the medical history of the patient and her family. The occurrence of a three-tooth fusion, and no supernumerary tooth was confirmed.

Enantiomeric purity determination of acetyl-L-carnitine by reversed-phase high-performance liquid chromatography using chiral derivatization

An indirect HPLC enantioseparation method for the determination of acetyl-D-carnitine (D-AC) in acetyl-L-carnitine (L-AC) was developed. L-AC was derivatized with a chiral amino compound which has a chromophore for UV detection. Six chiral amino compounds were examined as chiral derivatization reagents. Among them, enantiomers of acetylcarnitine derivatized with L-alanine-beta-naphthylamide (L-Ala-beta-NA) were successfully separated on an ODS column within 10 min with Rs = 1.94 and alpha = 1.10. Quantitation was achieved through UV detection at 254 nm. The derivatization reaction of L-AC with L-Ala-beta-NA was completed in less than 10 min at room temperature (ca. 20 degrees C). Validation data such as linearity, detection limit, and precision are also presented. The detection limit of D-AC in L-AC in this method was below 0.05% (visual evaluation). This method was found to be applicable as a practical quality control method for the enantiomeric purity determination of L-AC.

Molecular characterization of type-specific capsular polysaccharide biosynthesis genes of Streptococcus agalactiae type Ia

The type-specific capsular polysaccharide (CP) of a group B streptococcus, Streptococcus agalactiae type Ia, is a high-molecular-weight polymer consisting of the pentasaccharide repeating unit 4)-[alpha-D-NeupNAc-(2-->3)-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1- ->3 )]-beta-D-Galp-(1-->4)-beta-D-Glcp-(1. Here, cloning, sequencing, and transcription of the type Ia-specific capsular polysaccharide synthesis (cps) genes and functional analysis of these gene products are described. A 26-kb DNA fragment containing 18 complete open reading frames (ORFs) was cloned. These ORFs were designated cpsIaA to cpsIaL, neu (neuraminic acid synthesis gene) A to D, orf1 and ung (uracil DNA glycosylase). The cps gene products of S. agalactiae type Ia were homologous to proteins involved in CP synthesis of S. agalactiae type III and S. pneumoniae serotype 14. Unlike the cps gene cluster of S. pneumoniae serotype 14, transcription of this operon may start from cpsIaA, cpsIaE, and orf1 because putative promoter sequences were found in front of these genes. Northern hybridization, reverse transcription-PCR, and primer extension analyses supported this hypothesis. DNA sequence analysis showed that there were two transcriptional terminators in the 3' end of this operon (downstream of orf1 and ung). The functions of CpsIaE, CpsIaG, CpsIaI, and CpsIaJ were examined by glycosyltransferase assay by using the gene products expressed in Escherichia coli JM109 harboring plasmids containing various S. agalactiae type Ia cps gene fragments. Enzyme assays suggested that the gene products of cpsIaE, cpsIaG, cpsIaI, and cpsIaJ are putative glucosyltransferase, beta-1, 4-galactosyltransferase, beta-1,3-N-acetylglucosaminyltransferase, and beta-1,4-galactosyltransferase, respectively.

Preparation and evaluation of double-phased mucoadhesive suppositories of lidocaine utilizing Carbopol and white beeswax

In an attempt to restrict drug absorption from suppositories to only the lower rectum, mucoadhesive lidocaine (LID) suppositories were prepared using Witepsol H-15 as a base, and Carbopol 934P (CP) and white beeswax (WAX) as additives. CP has a mucoadhesive property and WAX gives the suppositories stiffness. The suppositories containing 10% CP and 20% WAX stayed in the lower recta of rats for at least 2 h. Double-phased suppositories consisting of a front layer containing 10% CP and 20% WAX and a terminal layer containing LID and various amounts of CP were prepared. In vitro release profiles of LID from double-phased suppositories were similar to conventional single-phased suppositories containing CP alone. Values of AUC(0-6 h) and MRT of LID after administration of double-phased suppositories to rabbits were larger than those for single-phased suppositories with or without CP. On the other hand, the initial plasma metabolites concentrations after administration of double-phased suppositories were significantly lower and tended to exhibit delayed T(max) compared to single-phased suppositories. These results suggest that the double-phased mucoadhesive suppositories suppress initial metabolism of LID, and may be useful for improving bioavailabilities of drugs, like LID, which accept first-pass effect considerably.

Early axonal and glial pathology in fetal sheep brains with leukomalacia induced by repeated umbilical cord occlusion

We conducted a chronic preparation experiment involving near term fetal sheep to evaluate the contribution of umbilical cord occlusion to fetal brain injury. In experimental groups (n = 11), complete cord occlusion for 3 min followed by 5 min release, repeated 5 times were performed at 3 days after initial surgery. Instrumental cases without cord occlusion (n = 3) and uninstrumental twins (n = 6) were also examined as controls. Multiple necrotic foci predominantly in the periventricular white matter were found in the fetal brains examined at 1-3 days after cord occlusion. To estimate the contribution of early axonal and glial reaction to brain injury the following immunohistochemical study was performed. In the lesions, coagulation necrosis, axonal swelling and microglial activation were demonstrated with amyloid precursor protein or ionized calcium binding adapter molecule 1 immunohistochemistry. The induction of tumor necrosis factor alpha and inducible nitric oxide synthase were also detected immunohistochemically in the microglia at 1 and 3 days after cord occlusion. In contrast, the reaction of glial fibrillary acidic protein positive astrocytes was faint at 1 day after occlusion, but the induction of cyclooxygenase-2 was observed. These findings suggest the glial reaction of cytokines and free radicals induced by fetal hypoxia may contribute to the occurrence of brain injury.

Effects of ammonia solution on the gastric mucosa in cirrhotic rats and therapeutic effects of geranylgeranylacetone

BACKGROUND

We designed an animal model in order to clarify whether Helicobacter pylori infection causes the gastric mucosal lesion frequently seen in cirrhotic patients.

METHODS

Ammonia (NH3) solution was given to rats with carbon tetrachloride-induced cirrhosis. The gastric mucosal hexosamine (Hx) content and histopathological findings in the cirrhotic rats were analysed and compared with those of the intact liver rats. Moreover, the usefulness of geranylgeranylacetone (GGA) was investigated in both rat groups. Both rat groups were subdivided according to the treatment as follows: a control group, an NH3 (0.02% solution) group, and an NH3 + GGA (400 mg/kg per day) group; and fed for 4 weeks.

RESULTS

The gastric mucosal Hx content of the control group of the cirrhotic rats (16.7 +/- 5.2 microg/mg) was significantly lower than that of the control group of the intact liver rats (26.6 +/- 4.5 microg/mg, P < 0.05). In the cirrhotic rats, the Hx content of both the NH3 (31.9 +/- 13.1 microg/mg) and the NH3 + GGA group (31.9 +/- 9.8 microg/mg) was significantly higher than the Hx content of the control group (P < 0.05). Microscopically, in the cirrhotic rats, while scattered mucosal erosions were recognized in three of five rats of the NH3 group, there were no erosions in any rats of the NH3 + GGA group.

CONCLUSIONS

These data suggest that the gastric mucosal defence mechanism is defective in liver cirrhosis and that NH3 enhances this defensive mechanism by acting as mild irritant; however, in some cirrhotics this results in gastric erosion due to excessive irritation. Geranylgeranylacetone protects the gastric mucosa against NH3 irritation in cirrhotics without enhancing the Hx content. Thus, H. pylori infection may be a possible cause of the gastric mucosal lesion in patients with liver cirrhosis. The mechanism of the therapeutic effect of GGA is not due to an enhancement of the gastric mucosal Hx content.

Visualization of the endometrium by intrauterine sonography

Thirty-five women with normal menstrual cycles underwent transvaginal and high-frequency (15- or 20-MHz) intrauterine sonographic examinations for the assessment of the endometrium. Five sonographic patterns of endometrium were recognized by both sonographic techniques, but the pattern visualized differed between techniques in 9 women (26%). The higher resolution of intrauterine sonography provided more detail of the endometrium. Our preliminary experience indicates that high-frequency intrauterine sonography enables more detailed visualization of changes in the endometrium during the menstrual cycle than does transvaginal sonography.

Regulatory interaction of PRL1 WD protein with Arabidopsis SNF1-like protein kinases

Mutation of the PRL1 gene, encoding a regulatory WD protein, results in glucose hypersensitivity and derepression of glucose-regulated genes in Arabidopsis. The yeast SNF1 protein kinase, a key regulator of glucose signaling, and Arabidopsis SNF1 homologs AKIN10 and AKIN11, which can complement the Deltasnf1 mutation, were found to interact with an N-terminal domain of the PRL1 protein in the two-hybrid system and in vitro. AKIN10 and AKIN11 suppress the yeast Deltasnf4 mutation and interact with the SNF4p-activating subunit of SNF1. PRL1 and SNF4 bind independently to adjacent C-terminal domains of AKIN10 and AKIN11, and these protein interactions are negatively regulated by glucose in yeast. AKIN10 and AKIN11, purified in fusion with glutathione S-transferase, undergo autophosphorylation and phosphorylate a peptide of sucrose phosphate synthase in vitro. The sucrose phosphate synthase-peptide kinase activity of AKIN complexes detected by immunoprecipitation is stimulated by sucrose in light-grown Arabidopsis plants. In comparison with wild type, the activation level of AKIN immunocomplexes is higher in the prl1 mutant, suggesting that PRL1 is a negative regulator of Arabidopsis SNF1 homologs. This conclusion is supported by the observation that PRL1 is an inhibitor of AKIN10 and AKIN11 in vitro.

The current status of dentistry, particularly pediatric dentistry, among the countries and territories of Asia

The number of dentists in Japan may be too high. The ratio of dentists/population, in China, Indonesia, Thailand, and Malaysia, is less than 1 dentist for every 10,000 people. From this data, it can be seen that there is a shortage of dentists in China, Indonesia, Thailand, and Malaysia. The shortage of pediatric dentists in these Asian countries is serious, particularly in the Philippines where the number of children with dental caries is increasing. There is an urgent need to increase the number of pediatric dentists in these countries. However, one problem is that dental schools in the Philippines and Singapore, do not have a department of pediatric dentistry.