TGF-beta1 up-regulates paxillin protein expression in malignant astrocytoma cells: requirement for a fibronectin substrate

Cytokines can influence the interactions between members of the integrin cell adhesion receptor family and the extracellular matrix thereby potentially affecting cell function and promoting cell adhesion, growth and migration of malignant astrocytoma tumor cells. As malignant astrocytoma cells synthesize TGF-beta1 in vivo, we analysed the effects of TGF-beta1 on signaling events associated with integrin receptor ligation, focusing on the effects on paxillin, a phosphorylated adaptor protein, that acts as a scaffold for signaling molecules recruited to focal adhesions. TGF-beta1-stimulation of primary astrocytes and serum-starved U-251MG malignant astrocytoma cells attached to fibronectin induced a substantial increase in the levels of paxillin protein (fivefold increase at 2.0 ng/ml) in a dose- and time-dependent manner compared to the levels observed on plating onto fibronectin in the absence of stimulation. In the astrocytoma cells, this resulted in an increase in the pool of tyrosine-phosphorylated paxillin, although it did not appear to alter the extent of phosphorylation of the paxillin molecules. In contrast, in primary astrocytes the protein levels were upregulated in the absence of a parallel increase in phosphorylation. The TGF-beta1-stimulated increase in paxillin levels required ligation of the fibronectin receptor, as it was not induced when the cells were plated onto vitronectin, collagen or laminin. The increase in the pool of paxillin on TGF-beta1 stimulation of the fibronectin-plated astrocytoma cells was associated with an increase in translation, but was not associated with an increase in the steady-state levels of paxillin mRNA. Stimulation with TGF-beta1 on a fibronectin substrate increased subsequent attachment and spreading of U-251MG cells onto fibronectin and, to a lesser extent, vitronectin, but not collagen. Our results indicate that physiologic levels of TGF-beta1 stimulate the expression of paxillin protein at the level of translation through a process that requires engagement of the fibronectin receptor, and promotes attachment and spreading of malignant astrocytoma cells on fibronectin.

[Two pediatric cases of malignant hyperthermia caused by sevoflurane]

We experienced two cases of malignant hyperthermia (MH) triggered by sevoflurane. Case 1 was a six-year-old girl, 15.8 kg, undergoing strabismus repair. She had flat back, elevated diaphragm and high arched palate. Anesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Her trachea was intubated without the use of muscle relaxant. Thirty minutes after the induction of anesthesia, ETco2 was over 60 mmHg despite hyperventilation. Muscle rigidity of legs and the rise in temperature were noted. MH was diagnosed and dantrolene i.v. was administered. Her maximum esophageal temperature was 40.2 degrees C. ETco2 and temperature returned to baseline values after dantrolene administration. Creatine phosphokinase (CK) level was 252 U.l-1 preoperatively, and 1690 U.l-1 next day. Case 2 was a year-and-9-month-old boy undergoing accessory ear resection. Anesthesia was induced with sevoflurane and nitrous oxide in oxygen. His trachea was intubated with an aid of vecuronium. Forty minutes after administration of sevoflurane his temperature rose to 38.6 degrees C with heart rate 191 bpm and Spo2 93%, and muscle rigidity of legs. MH was diagnosed and dantrolene was administered. His highest temperature was 39.3 degrees C and was reduced promptly after dantrolene. Postoperatively he was noted to have downslanting palpebral fissures, micrognathia, low set ears, and a single crease of the fifth finger and diagnosed as King syndrome which is reported to have association with MH. Both patients had no history of anesthesia nor abnormal family history. Both of them were rescued with dantrolene and recovered without sequelae.

Turner syndrome and Xp deletions: clinical and molecular studies in 47 patients

Although clinical features of Turner syndrome have primarily been explained by the dosage effects of SHOX (short stature homeobox-containing gene) and the putative lymphogenic gene together with chromosomal effects leading to nonspecific features, several matters remain to be determined, including modifying factors for the effects of SHOX haploinsufficiency, chromosomal location of the lymphogenic gene, and genetic factors for miscellaneous features such as multiple pigmented nevi. To clarify such unresolved issues, we examined clinical findings in 47 patients with molecularly defined Xp deletion chromosomes accompanied by the breakpoints on Xp21-22 (group 1; n = 19), those accompanied by the breakpoints on Xp11 (group 2; n = 16), i(Xq) or idic(X)(p11) chromosomes (group 3; n = 8), and interstitial Xp deletion chromosomes (group 4; n = 4). The deletion size of each patient was determined by fluorescence in situ hybridization and microsatellite analyses for 38 Xp loci including SHOX, which was deleted in groups 1-3 and preserved in group 4. The mean GH-untreated adult height was -2.2 SD in group 1 and -2.7 SD in group 2 (GH-untreated adult heights were scanty in group 3). The prevalence of spontaneous breast development in patients aged 12.8 yr or more (mean +/- 2 SD for B2 stage) was 11 of 11 in group 1, 7 of 12 in group 2, and 1 of 7 in group 3. The prevalence of wrist abnormality suggestive of Madelung deformity was 8 of 18 in group 1 and 2 of 23 in groups 2 and 3, and 9 of 18 in patients with spontaneous puberty and 1 of 23 in those without spontaneous puberty. The prevalence of short neck was 1 of 19 in group 1 and 7 of 24 in groups 2 and 3. Soft tissue and visceral anomalies were absent in group 1 preserving the region proximal to Duchenne muscular dystrophy and were often present in groups 2 and 3 missing the region distal to monoamine oxidase A (MAOA). Multiple pigmented nevi were observed in groups 1-3, with the prevalence of 0 of 7 in patients less than 10 yr of age and 15 of 36 in those 10 yr or older regardless of the presence or absence of spontaneous puberty. Turner phenotype was absent in group 4, including a fetus aborted at 21 wk gestation who preserved the region distal to MAOA. The results provide further support for the idea that clinical features in X chromosome aberrations are primarily explained by haploinsufficiency of SHOX and the lymphogenic gene and by the extent of chromosome imbalance in mitotic cells and pairing failure in meiotic cells. Furthermore, it is suggested that 1) expressivity of SHOX haploinsufficiency in the limb and faciocervical regions is primarily influenced by gonadal function status and the presence or absence of the lymphogenic gene, respectively; 2) the lymphogenic gene for soft tissue and visceral stigmata is located between Duchenne muscular dystrophy and MAOA; and 3) multiple pigmented nevi may primarily be ascribed to cooperation between a hitherto unknown genetic factor and an age-dependent factor other than gonadal E.

Synthetic studies toward gambierol. Convergent synthesis of the octacyclic polyether core

[structure: see text]. A convergent synthetic route to the octacyclic polyether core of gambierol, a marine polycyclic ether toxin, has been developed. The synthesis involves construction of two fragments representing the ABC and EFGH ring systems followed by their coupling via a B-alkyl Suzuki reaction.

Regulation of Ras and Rho small G proteins by SHP-2

BACKGROUND

Hepatocyte growth factor/scatter factor (HGF/SF) induces cell scattering through the tyrosine kinase-type HGF/SF receptor, c-Met. We have previously shown that SHP-2, a protein tyrosine phosphatase, positively regulates the HGF/SF-induced cell scattering through modulating the activity of Rho to form stress fibres and focal adhesions. To further investigate the role of SHP-2 in HGF/SF-induced cell scattering, we have now examined the effect of a dominant active mutant of SHP-2 (SHP-2-DA).

RESULTS

Expression of SHP-2-DA markedly increased the formation of lamellipodia with ruffles, while it decreased the accumulation of E-cadherin and beta-catenin at cell-cell adhesion sites in MDCK cells. In addition, expression of SHP-2-DA markedly enhanced cell scattering of MDCK cells in response to HGF/SF. Expression of SHP-2-DA induced the activation of MAP kinase without HGF/SF stimulation, whereas an inhibitor of MEK partly reversed the SHP-2-DA-induced morphological phenotypes. Furthermore, expression of either a dominant-active mutant of Rho or Vav2 also reversed the SHP-2-DA-induced morphological phenotypes.

CONCLUSION

These results indicate that SHP-2 plays a crucial role in the HGF/SF-induced cell scattering through the regulation of two distinct small G proteins, Ras and Rho.

Iodide organification defects resulting from cosegregation of mutated and null thyroid peroxidase alleles

This report describes an intriguing combination of the thyroid peroxidase (TPO) alleles resulting in an iodide organification defect. Sequence analysis of the patient's TPO gene showed the presence of T-deletion in exon 14 of the TPO gene (T2512del). From the sequencing pattern, this new mutation of the TPO gene was thought to be homozygous. mRNA transfection studies in which mutated mRNA was transfected to CHO-K(1) cells by electroporation showed that the cells transfected with mutated mRNA expressed smaller TPO molecules than those of cells transfected with wild-type mRNA and that they had TPO activity. However, the smaller TPO molecules could not translocate onto the cell surface. To investigate T2512del in the parents, their genomic DNAs were sequenced. Results showed that the mother had T2512del but the father did not. However, when seven polymorphic positions reported earlier were analyzed, the mother showed two kinds of nucleotides at four positions but the patient and father showed only one nucleotide at all seven positions. We suspected a deletion of the TPO gene (2p25) in one of two second chromosomes, and analyzed the patient's chromosomes by FISH using TPO cDNA and N-myc genomic DNA as probes. N-myc genomic DNA exhibited two signals and TPO cDNA only one signal, although the G-band showed no morphological abnormalities. T2512-deleted and 2p25-deleted null alleles cosegregated from her parents, resulting in iodide organification defect in the patient.

Evidence as a HIV-1 self-defense vaccine of cyclic chimeric dodecapeptide warped from undecapeptidyl arch of extracellular loop 2 in both CCR5 and CXCR4

Novel conformation-specific antibodies were raised against a cyclic chimeric dodecapeptidyl multiple antigen peptide (cCD-MAP) constructed with a spacer-armed Gly-Asp dipeptide and two pentapeptides (S(169)-Q(170)-K(171)-E(172)-G(173) of CCR5 and E(179)-A(180)-D(181)-D(182)-R(183) of CXCR4) which are components of the undecapeptidyl arch (UPA: from R(168) to C(178) in CCR5, from N(176) to C(186) in CXCR4) of extracellular loop 2 (ECL2) in chemokine receptors (CCR5 and CXCR4). Of the antibodies raised, one monoclonal antibody, CPMAb-I (IgMkappa), reacted with cCD-MAP, but not with the linear chimeric dodecapeptide-MAP. The antibody reacted with the cells separately expressing CCR5 or CXCR4, but not with those not expressing the coreceptors. Moreover, the antibody markedly suppressed infection by X4, R5, or R5X4 virus in a dose-dependent manner in a new phenotypic assay for drug susceptibility of HIV-1 using CCR5-expressing Hela/CD4(+) cell clone 1-10 (MAGIC-5). Moreover, CPMAb-I interfered with LAV-1(BRU) infection (m.o.i. = 0.01) of Molt4#8 cells cocultured with CPMAb-I-producing hybridoma in the transwell, and significantly interfered with neither chemotaxis nor calcium influx induced with stromal cell-derived factor 1 alpha (SDF-1alpha). Thus, the antibody raised against the cCD-MAP provides powerful protection or defense against HIV-1 infection. We therefore propose the cCD-MAP or its derivative immunogen as a novel candidate for an HIV-1 coreceptor-based self-defense vaccine.

Hic-5-reduced cell spreading on fibronectin: competitive effects between paxillin and Hic-5 through interaction with focal adhesion kinase

Hic-5 is a paxillin homologue that is localized to focal adhesion complexes. Hic-5 and paxillin share structural homology and interacting factors such as focal adhesion kinase (FAK), Pyk2/CAKbeta/RAFTK, and PTP-PEST. Here, we showed that Hic-5 inhibits integrin-mediated cell spreading on fibronectin in a competitive manner with paxillin in NIH 3T3 cells. The overexpression of Hic-5 sequestered FAK from paxillin, reduced tyrosine phosphorylation of paxillin and FAK, and prevented paxillin-Crk complex formation. In addition, Hic-5-mediated inhibition of spreading was not observed in mouse embryo fibroblasts (MEFs) derived from FAK(-/-) mice. The activity of c-Src following fibronectin stimulation was decreased by about 30% in Hic-5-expressing cells, and the effect of Hic-5 was restored by the overexpression of FAK and the constitutively active forms of Rho-family GTPases, Rac1 V12 and Cdc42 V12, but not RhoA V14. These observations suggested that Hic-5 inhibits cell spreading through competition with paxillin for FAK and subsequent prevention of downstream signal transduction. Moreover, expression of antisense Hic-5 increased spreading in primary MEFs. These results suggested that the counterbalance of paxillin and Hic-5 expression may be a novel mechanism regulating integrin-mediated signal transduction.

Relationship between doppler-derived left ventricular diastolic function and exercise capacity in patients with myocardial infarction

Doppler echocardiographic indices of left ventricular (LV) diastolic function are widely used to evaluate the cardiac function of patients with cardiac disease. However, there have been few reports about the relationship between Doppler indices and exercise capacity and so 44 patients with myocardial infarction were investigated by cardiopulmonary exercise testing and 2-D and Doppler echocardiography. Diastolic performance was assessed using Doppler transmitral flow velocity and pulmonary venous flow velocity. The ratio of peak E wave velocity and peak A wave velocity (E/A) correlated with peak oxygen consumption (peak Vo2) (R=0.72), and there was a negative correlation between the deceleration time of E velocity (Dct) and peak Vo2 or anaerobic threshold (AT) (R=-0.65, -0.62, respectively). The ratio of peak S wave velocity and peak D wave velocity (S/D) negatively correlated with peak Vo2 (R=-0.58). Left ventricular ejection fraction did not correlate to exercise capacity. These results suggest that the Doppler echocardiographic indices of LV diastolic function correlate with exercise capacity in patients with mild cardiac dysfunction.

Congenital absence of the portal vein and role of liver transplantation in children

BACKGROUND/PURPOSE

Congenital absence of the portal vein (CAPV) is a subtype of congenital portosystemic shunt, which can cause a broad spectrum of clinical manifestations. The authors report on 4 patients with CAPV including a boy with CAPV-associated encephalopathy, which was resolved effectively by liver transplantation (LT).

METHODS

The case records of 4 pediatric patients with CAPV who were referred to the author's institution between 1984 and 1999 were reviewed.

RESULTS

The patients (3 boys and 1 girl) ranged in age at diagnosis from 0.8 to 14 years. Two patients had growth retardation or disturbed consciousness, and the other 2 had no specific manifestations. Not only high serum levels of bile acids, ammonia, and transaminases but also low plasma levels of branched-chain amino acids were common laboratory findings. The absent portal vein was replaced by a large portosystemic shunt, which connected the splanchnic vein to the inferior vena cava or the left renal vein. Two patients survived without any symptoms, but 1 with growth retardation died of hepatic failure. The other with encephalopathy did not respond to medical therapy and underwent LT, which resolved symptoms and metabolic disorders effectively.

CONCLUSIONS

Patients with CAPV do not always have a good prognosis. They should be followed up with careful observation of their symptoms, hepatic function, and metabolic abnormalities. LT might be indicated for patients with symptomatic CAPV unresponsive to medical therapy.

Cooperation of Cdc42 small G protein-activating and actin filament-binding activities of frabin in microspike formation

Frabin is a GDP/GTP exchange protein for Cdc42 with actin filament (F-actin)-binding activity. Cdc42 is a small GTP-binding protein that forms filopodia-like microspikes in a variety of cells. Expression of frabin indeed forms microspikes through at least activation of Cdc42 in MDCK cells and fibroblasts such as COS7, L, and NIH3T3 cells. However, the role of the F-actin-binding activity of frabin in the microspike formation remains unknown. We have examined here this role of frabin by expressing various frabin mutants, which have lost Cdc42-activating or F-actin-binding activity, with or without a dominant active mutant of Cdc42 in MDCK and COS7 cells. We show here that for the microspike formation, either of the Cdc42-activating and F- actin-binding activities of frabin alone is not sufficient and both the activities are necessary and that both the activities play a cooperative role in the microspike formation. The present results, together with the earlier finding that Cdc42 reorganizes the actin cytoskeleton at least through the N-WASP-Arp2/3 complex, suggest that frabin directly and indirectly reorganizes the actin cytoskeleton through its F-actin-binding and Cdc42-activating activities, respectively, in a cooperative manner, eventually leading to microspike formation.

alpha-catenin-independent recruitment of ZO-1 to nectin-based cell-cell adhesion sites through afadin

ZO-1 is an actin filament (F-actin)-binding protein that localizes to tight junctions and connects claudin to the actin cytoskeleton in epithelial cells. In nonepithelial cells that have no tight junctions, ZO-1 localizes to adherens junctions (AJs) and may connect cadherin to the actin cytoskeleton indirectly through beta- and alpha-catenins as one of many F-actin-binding proteins. Nectin is an immunoglobulin-like adhesion molecule that localizes to AJs and is associated with the actin cytoskeleton through afadin, an F-actin-binding protein. Ponsin is an afadin- and vinculin-binding protein that also localizes to AJs. The nectin-afadin complex has a potency to recruit the E-cadherin-beta-catenin complex through alpha-catenin in a manner independent of ponsin. By the use of cadherin-deficient L cell lines stably expressing various components of the cadherin-catenin and nectin-afadin systems, and alpha-catenin-deficient F9 cell lines, we examined here whether nectin recruits ZO-1 to nectin-based cell-cell adhesion sites. Nectin showed a potency to recruit not only alpha-catenin but also ZO-1 to nectin-based cell-cell adhesion sites. This recruitment of ZO-1 was dependent on afadin but independent of alpha-catenin and ponsin. These results indicate that ZO-1 localizes to cadherin-based AJs through interactions not only with alpha-catenin but also with the nectin-afadin system.

Development of growth hormone and adrenocorticotropic hormone deficiencies in patients with prenatal or perinatal-onset hypothalamic hypopituitarism having invisible or thin pituitary stalk on magnetic resonance imaging

A gradual loss of anterior pituitary hormones is suspected in patients treated with irradiation due to brain tumors. Development of growth hormone deficiency (GHD) with age has been documented in patients with idiopathic GHD. A gradual loss of adrenocorticotropic hormone (ACTH) secretion has been also shown in a patient with severe GHD and an invisible pituitary stalk on magnetic resonance imaging (MRI). The purpose of this longitudinal and cross-sectional study was to evaluate the gradual loss of growth hormone (GH) and ACTH in a homogeneous group of patients with hypopituitarism. Twenty-eight patients (23 males, 5 females) from four hospitals were diagnosed as having prenatal or perinatal-onset hypothalamic hypopituitarism. They had an abnormal pituitary stalk on MRI (invisible in 18 patients, thin in 10 patients) without any other organic disease of the brain. Each patient had GHD upon initial evaluation. Height (n=20) was analyzed as standard deviation score (SDS). Longitudinal (n=8) and cross-sectional (n=28) GH secretion capacity was evaluated by GH peaks, in response to insulin tolerance test (ITT) and growth hormone releasing factor test (GRF test). Longitudinal (n=10) and cross-sectional (n=28) ACTH secretion capacity was evaluated by cortisol peaks in response to ITT. Height SDS decreased each year in all the untreated patients after birth. GH peaks decreased gradually with age. Longitudinal data showed decreased GH peaks with age in seven out of eight patients using ITT and in all four patients using GRF tests. Cortisol peaks also decreased gradually together with signs and symptoms for adrenal deficiency such as general fatigue. Cortisol peaks of less than 414 nmol/L (15 microg/dl) in response to ITT were seen in 24% of the tests before age 10 and 56% before age 25. In conclusion, GHD and ACTH deficiency developed gradually in patients with prenatal or perinatal-onset hypothalamic hypopituitarism who had invisible or thin pituitary stalks examined by MRI.

Roles of cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1

Gab-1 is a multiple docking protein that is tyrosine phosphorylated by receptor tyrosine kinases such as c-Met, hepatocyte growth factor/scatter factor receptor, and epidermal growth factor receptor. We have now demonstrated that cell-cell adhesion also induces marked tyrosine phosphorylation of Gab-1 and that disruption of cell-cell adhesion results in its dephosphorylation. An anti-E-cadherin antibody decreased cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1, whereas the expression of E-cadherin specifically induced tyrosine phosphorylation of Gab-1. A relatively selective inhibitor of Src family kinases reduced cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1, whereas expression of a dominant-negative mutant of Csk increased it. Disruption of cell-cell adhesion, which reduced tyrosine phosphorylation of Gab-1, also reduced the activation of mitogen-activated protein kinase and Akt in response to cell-cell adhesion. These results indicate that E-cadherin-mediated cell-cell adhesion induces tyrosine phosphorylation by a Src family kinase of Gab-1, thereby regulating the activation of Ras/MAP kinase and phosphatidylinositol 3-kinase/Akt cascades.

Isolation, structure determination, and synthesis of neodysiherbaine A, a new excitatory amino acid from a marine sponge

[structure: see text] A new excitatory amino acid, neodysiherbaine A (2), was isolated as a minor constituent of the aqueous extract from the marine sponge Dysidea herbacea. The structure was deduced by spectroscopic methods and established unambiguously by the total synthesis. The present synthesis, including as a key step cross-coupling of the 6/5-bicyclic core with an amino acid residue, is useful in constructing its structural analogues.

The use of ultrasound for drug delivery

Ultrasound has been in use for the last three decades as a modality for diagnostic imaging in medicine. Recent studies have shown that nonthermal ultrasound energy could be applied for targeting or controlling drug release. This new concept of therapeutic ultrasound combined with drugs has induced interest in various medical fields. Enhanced effects of thrombolytic agents such as urokinase and TPA with acoustic energy have been demonstrated. Ultrasound transducer-tipped catheters are being developed for treatment of cardiovascular diseases. Other devices with ultrasound transducers implanted in transdermal drug patches are also being evaluated for possible delivery of insulin through the skin. Echo contrast microbubbles could also be used to carry and release genes to various tissues and lesions. Chemical activation of drugs by ultrasound energy for treatment of cancers is another new field recently termed "sonodynamic therapy." Various examples of ultrasound application are under investigation that could lead to revolutionary drug delivery systems of the future.

[Assessment of general movements at routine medical examination of one-month-old infants]

On routine medical examination of one-month-old infants, general movements (GMs) were video-recorded for about 5 minutes of 252 infants born at Kyoto City Hospital or other hospitals, including the infants discharged from the NICU. Their ages ranged from 39 postmenstrual to 8 post-term weeks. One of the experimenters assessed 181 infants among 252 available for assessment of their GMs twice at intervals of more than one month without being informed about their clinical histories. The subjects included 19 low-birthweight infants, and their average age was 3.5 post-term weeks. The assessment was carried out in comparison to the "gold standard" GMs depicted in a demonstration video produced by the GMs Trust. The Kappa value for intra-observer concordance was 0.85. Twenty (11.0%) out of the 181 infants were judged abnormal because of their poor repertoire of GMs in both the first and second assessment. Neither cramped synchronized GMs nor chaotic ones were observed. Meanwhile, 155 (85.6%) out of the 181 infants were found to be normal. The incidence of abnormal GMs was significantly higher among infants with history of asphyxia and/or respiratory distress than among low-risk infants. There of the experimenters independently assessed GMs of 50 infants among 181 which had been video-recorded between June and September 1998. The inter-observer concordance was higher among the low-birth weight infants than among full-term ones. In conclusion, qualitative assessment of GMs by an experienced observer at routine medical examination of one-month old infants is a useful method for the follow-up of high-risk infants.

Complex regulation of CDK2 and G1 arrest during neuronal differentiation of human prostatic cancer TSU-Prl cells by staurosporine

We are interested in the possibility of new prostate cancer therapy that would control tumor malignancy via the induction of terminal cell differentiation. We have previously reported that staurosporine induced remarkable inhibition of cell proliferation and neuronal differentiation in human prostatic cancer TSU-Pr1 cells. In the present study, we investigated the alteration of cyclin-dependent kinase (CDK) activities and cell cycle in differentiated TSU-Pr1 cells. Treatment of TSU-Pr1 cells with staurosporine resulted in G1 arrest and suppression of CDK2 activity. Protein levels of CDK2 were essentially unchanged during this time. p21 protein, however, rapidly increased for 6 hours after treatment with staurosporine. p27 protein also increased gradually for 12 to 72 hours after treatment. CDK2-bound p21 and CDK2-bound p27 also increased. These results suggest that an increase in p21 and p27 protein causes increased binding with CDK2 and inhibition of CDK2 activity. We propose that the complex regulation of CDK2 plays a key role in G1 arrest of TSU-Pr1 cells after treatment with staurosporine.

Reversed-phase liquid chromatographic separation of enantiomers on polysaccharide type chiral stationary phases

The direct chiral separation by chiral stationary phases (CSPs) is one of the most important techniques to analyze enantiomeric purity as well as to get enantiomerically pure material quickly. Among various types of CSPs, polysaccharide type CSPs are well known by their versatility and durability. They are not only effective under normal-phase conditions, but also under reversed-phase conditions. In order to get a good separation under the reversed-phase conditions, it is the key to choose an appropriate mobile phase. For example, a simple mixture of water/acetonitrile or water/methanol are sufficient for a neutral analyte, while it is necessary to use an acidic solution instead of water for an acidic analyte and a solution of a chaotropic salt (or a basic solution) for a basic analyte, respectively. The paper also presents lists of more than 350 separation examples that include 22 validated methods for drug analyses from serum, plasma, or urine samples on polysaccharide type CSPs under reversed-phase conditions.

Compound heterozygous mutations in the gamma subunit gene of ENaC (1627delG and 1570-1G-->A) in one sporadic Japanese patient with a systemic form of pseudohypoaldosteronism type 1

The systemic form of pseudohypoaldosteronism type 1 (PHA1) is a rare autosomal recessive disorder with salt-wasting, hyperkalemia, metabolic acidosis, and multiorgan aldosterone unresponsiveness. Recently, this form of PHA1 was found to be caused by the loss-of-function mutations in the gene of each subunit (alpha, beta, and gamma) of the epithelial sodium channel (ENaC). To investigate the molecular basis of one sporadic Japanese patient with a systemic form of PHA1, we determined the nucleotide sequence of the genes of every subunit of ENaC of this patient. The patient was found to be a compound heterozygote for one base deletion in exon 12 (1627delG) in combination with 1570-1-->GA substitution at the 5' splice acceptor site of intron 11 in the gamma subunit gene of ENaC. The 1627delG mutation altered a reading frame, resulting in a premature stop codon in exon 12. Messenger RNA from the allele harboring the splice site mutation was not identified by RT-PCR. In conclusion, two novel mutations in the gamma subunit gene of ENaC caused systemic PHA1 in the sporadic Japanese patient. Identification of the molecular basis of PHA1 is helpful for early diagnosis and understanding the pathophysiology of the disease.

c-Mos forces the mitotic cell cycle to undergo meiosis II to produce haploid gametes

The meiotic cycle reduces ploidy through two consecutive M phases, meiosis I and meiosis II, without an intervening S phase. To maintain ploidy through successive generations, meiosis must be followed by mitosis after the recovery of diploidy by fertilization. However, the coordination from meiotic to mitotic cycle is still unclear. Mos, the c-mos protooncogene product, is a key regulator of meiosis in vertebrates. In contrast to the previous observation that Mos functions only in vertebrate oocytes that arrest at meiotic metaphase II, here we isolate the first invertebrate mos from starfish and show that Mos functions also in starfish oocytes that arrest after the completion of meiosis II but not at metaphase II. In the absence of Mos, meiosis I is followed directly by repeated embryonic mitotic cycles, and its reinstatement restores meiosis II and subsequent cell cycle arrest. These observations imply that after meiosis I, oocytes have a competence to progress through the embryonic mitotic cycle, but that Mos diverts the cell cycle to execute meiosis II and remains to restrain the return to the mitotic cycle. We propose that a role of Mos that is conserved in invertebrate and vertebrate oocytes is not to support metaphase II arrest but to prevent the meiotic/mitotic conversion after meiosis I until fertilization, directing meiosis II to ensure the reduction of ploidy.