Clinical and molecular studies in 15 females with ring X chromosomes: implications for r(X) formation and mental development

We report clinical and molecular findings in 15 Japanese mosaic females with r(X) chromosomes, 45,X/46,X,r(X), confirmed by fluorescence in situ hybridization (FISH) analysis for DXZ1 and whole X chromosome painting. Cases 1-3, 5-7, and 11-13 had mental retardation (MR), the remaining cases being free from MR. FISH analysis showed that XIST was absent from the r(X) chromosomes in cases 1-4 and was present on the r(X) chromosomes in cases 5-15. X-inactivation analysis for the methylation status of the AR gene indicated that, of eight cases with XIST-positive r(X) chromosomes in more than 10% (23%-62%) of lymphocytes (cases 5-12), cases 5-10 had selective X-inactivation, whereas cases 11 and 12 had active X disomy. Microsatellite analysis for multiple loci on the pericentromeric region revealed that, of 11 cases with r(X) chromosomes in more than 10% (13%-62%) of lymphocytes (cases 1, 2, and 4-12), cases 1, 2, and 5-10 had heterozygous alleles for at least one locus, whereas cases 4, 11, and 12 had single alleles for all the loci examined. The results suggest that the r(X) and normal X chromosomes could be of biparental or uniparental origin, and that mental status in females with r(X) chromosomes is determined by multiple factors, including the presence or absence of XIST on the r(X) chromosomes and the size and frequency of active r(X) chromosomes, in addition to co-incidental genetic and environmental factors.

Three novel PHEX gene mutations in Japanese patients with X-linked hypophosphatemic rickets

X-linked hypophosphatemic rickets (XLH) is an X-linked dominant disorder characterized by renal phosphate wasting, abnormal vitamin D metabolism, and defects of bone mineralization. The phosphate-regulating gene on the X-chromosome (PHEX) that is defective in XLH has been cloned, and its location identified at Xp22.1. It has been recognized to be homologous to certain endopeptidases. So far, a variety of PHEX mutations have been identified mainly in European and North American patients with XLH. To analyze the molecular basis of four unrelated Japanese families with XLH, we determined the nucleotide sequence of the PHEX gene of affected members. We detected a new nonsense mutation (R198X) in exon 5, a new 3 nucleotides insertion mutation in exon 12 and a new missense mutation (L160R) in exon 5 as well as a previously reported nonsense mutation in exon 8 (R291X). These results suggest that: 1) PHEX gene mutations are responsible for XLH in Japanese patients, and 2) PHEX gene mutations are heterogeneous in the Japanese population similarly to other ethnic populations.

[A case of MPO ANCA associated glomerulonephritis with interstitial pneumonitis complicated with lung tuberculosis and pericarditis]

The main target organs of myeloperoxidase (MPO) antineutrophil cytoplasmic antibodies (ANCA)-related disease are the kidney and lung. This report describes a 71-year-old man with rapidly progressive glomerulonephritis (RPGN) and interstitial pneumonitis associated with MPO ANCA. The patient was admitted to our hospital because of bloody sputum, low grade fever and appetite loss on October, 1998. He was diagnosed as having interstitial pneumonitis from the findings of chest X-ray and CT examinations. Moderate proteinuria and hematuria, renal dysfunction(serum creatinine: 5.6 mg/dl, BUN: 58.0 mg/dl) and positivity for MPO ANCA were noted. He was negative for anti-glomerular antibody and PR3-ANCA. Renal biopsy was performed and revealed crescentic glomerulonephritis without deposition of immunoglobulins. Therefore, the diagnosis of pauci immune type RPGN was made. Pulse therapy with methylprednisolone(1.0 g/day x 3 days) following oral administration of prednisolone (60 mg/day) found marked improvement of renal function maintenance and interstitial pneumonitis, respectively. However, he died because of lung tuberculosis and acute tuberculous pericarditis during treatment with prednisolone. In this case, MPO ANCA might have been directly associated with both RPGN and interstitial pneumonitis. Furthermore, chronic lung disease, such as interstitial pneumonitis, is important as a preceding disease of RPGN. MPO ANCA-related disease is more frequent in aged persons, therefore particular attention should be paid during their treatment with an immunosuppressant.

A nonproteolytic function of the proteasome is required for the dissociation of Cdc2 and cyclin B at the end of M phase

Inactivation of cyclin B-Cdc2 kinase at the exit from M phase depends on the specific proteolysis of the cyclin B subunit, whereas the Cdc2 subunit remains present at nearly constant levels throughout the cell cycle. It is unknown how Cdc2 escapes degradation when cyclin B is destroyed. In Xenopus egg extracts that reproduce the exit from M phase in vitro, we have found that dissociation of the cyclin B-Cdc2 complex occurred under conditions where cyclin B was tethered to the 26S proteasome but not yet degraded. The dephosphorylation of Thr 161 on Cdc2 was unlikely to be necessary for the dissociation of the two subunits. However, the dissociation was dependent on the presence of a functional destruction box in cyclin B. Cyclin B ubiquitination was also, by itself, not sufficient for separation of Cdc2 and cyclin B. The 26S proteasome, but not the 20S proteasome, was capable of dissociating the two subunits. These results indicate that the cyclin B and Cdc2 subunits are separated by the proteasome through a mechanism that precedes proteolysis of cyclin B and is independent of proteolysis. As a result, cyclin B levels decrease on exit from M phase but Cdc2 levels remain constant.

18O-Labelling pattern of okadaic acid from H218O in dinoflagellate Prorocentrum lima elucidated by tandem mass spectrometry

Okadaic acid is a metabolite of the unicellular algae dinoflagellate. Its biosynthesis has attracted considerable attention since the skeletal structure was shown to be synthesized via an unprecedented route. However, its relevant intermediates or enzymes are unknown. In the course of our previous investigations on the oxygen source of okadaic acid by tandem mass spectrometry (CID MS/MS), we determined the level of 18O incorporation for each oxygen site from 18O2 and [18O2]acetate. In the present study, we examined H218O-labelling patterns of okadaic acid from dinoflagellates in comparison with salinomycin from actinomycetes and has provided intriguing information regarding biosynthesis. Unexpectedly, oxygen atoms originating from acetate were not labelled from H218O; this can not be accounted for by the usual metabolic route where acetyl-CoA is biosynthesized via pyruvate. Similar experiments for salinomycin revealed that all of its oxygen atoms derived from acetate or propionate were labelled by H218O. Another interesting feature is that two oxygen sites were derived from both O2 and H2O while the others were labelled only from O2. These results imply that an oxidation mechanism other than those in actinomycetes polyethers may be involved in the biosynthesis of okadaic acid.

[Cesarean section in a pregnant patient with placenta percreta involving the urinary bladder]

Placenta percreta involving adjacent structures is serious complication of pregnancy with a high mortality rate. A 32-year-old woman, gravida 4, para 3, who had previously undergone a cesarean section, was admitted to our hospital at 31 weeks' gestation for placenta previa. At 33 weeks' gestation, the diagnosis of placenta percreta with involvement of the urinary bladder was made by ultrasonography and magnetic resonance imaging. At 34 weeks' gestation, an elective cesarean section was scheduled. Anesthesia was maintained with sevoflurane in oxygen before delivery, and with nitrous oxide in oxygen, fentanyl and midazolam after delivery. During the operation, attempts to remove the placenta resulted in massive hemorrhage. Blood loss for the procedure was 13,800 g. Because of the extreme hemorrhage, we encountered hemorrhagic shock and postoperative complications despite the preoperative preparation. In case of placenta percreta, it is essential to prepare adequate volume of blood for transfusion at the start of surgery and secure large bore intravenous lines. A rapid transfusion device may be recommended. Regarding the anesthetic management, general anesthesia is preferable in consideration of the risk of hemorrhagic shock and the length of operation time. Furthermore, we need team approach and preoperative management to prevent the uncontrolled hemorrhage in such a severe case.

Immunohistochemical and chemical changes of beta-citryl-L-glutamate in the differentiation of bovine lens epithelial cells into lens fiber cells

Beta-citryl-L-glutamate (beta-CG) concentration was determined by HPLC during the differentiation of bovine lens epithelial cells into lens fiber cells in culture. beta-CG increased from 1 to 4 weeks of culture and then decreased slightly, while alpha-crystallin, a marker of lens cell differentiation, increased rapidly 4 weeks after the culture and continued to increase gradually until week 11. In addition, the localization of beta-CG was immunohistochemically examined using anti-beta-CG antibody. Cells around lentoid bodies were stained with anti-beta-CG antibody, whereas cells in the bodies were stained strongly with anti-gamma-crystallin antibody. These findings suggest that beta-CG accumulated immediately before the differentiation of the bovine lens epithelial cells into lens fiber cells and may play a role in regulating the differentiation of lens cells.

Characterization of mice antisera elicited with a ciguatoxin tetracyclic synthetic ring fragment (JKLM) conjugated to carrier proteins

As a good alternative to the lack of pure ciguatoxin (CTX), conjugates of JKLM ring fragment, a carboxylic derivative of the right-hand tetracyclic terminus portion of CTX-1B (the most potent CTX) with two carrier proteins have been synthesized. Two procedures using different amount of hapten were evaluated: (i) a bulk technique (3-5 mg) via the N-hydroxysuccinimide ester of the carboxylic fragment in the presence of a water-soluble carbodiimide according to the standard method in aqueous buffer, or (ii) a micro-scale technique (300 microg) via the mixed anhydride method performed in a reversed micellar medium. In both cases, bovine serum albumin and ovalbumin were respectively used for immunization of BALB/c mice and antibody screening by a solid phase enzyme-linked immunosorbent assay (ELISA). Using the conjugates obtained through the micro-scale procedure, a long-term immunization schedule appeared to be more efficient to specifically trigger the mice immune system. These antisera titers determined in an end-point titration standard ELISA format were found around 1/128,000 as compared to 1/16,000 obtained in the short-term protocol (immunogen prepared via the bulk procedure). In competitive inhibition ELISA experiments, both types of antisera did not significantly cross-react with a brevetoxin congener (PbTx-3), okadaic acid (OA), monensin or other polyether compounds, but only sera from the short-term protocol did show high cross-reactivity to CTX-1B (133%). With sera from the long-term protocol, a lower detection limit for JKLM (1.23 x 10(-9) M) was achieved by implementation of a biotin-avidin amplification system rather than by miniaturization of the assay in Terasaki plates. This study confirms the feasibility of the immunological approach for CTXs assay in fish tissues, but also emphasizes the importance of (i) the choice of the hapten to construct a relevant well-defined immunogen, (ii) the immunization schedule to obtain hapten-specific Abs still exhibiting high cross-reactivity to CTXs.

Nectin-3, a new member of immunoglobulin-like cell adhesion molecules that shows homophilic and heterophilic cell-cell adhesion activities

We have isolated a novel cell-cell adhesion system localized at cadherin-based adherens junctions (AJs). This system consists of at least nectin, a Ca(2+)-independent immunoglobulin-like adhesion molecule, and afadin, an actin filament-binding protein, that connects nectin to the actin cytoskeleton. Nectin constitutes a family consisting of two members, nectin-1 and -2. We have isolated here a third member of the nectin family and named it nectin-3. Nectin-3 has three splicing variants, nectin-3alpha (biggest), -3beta (middle), and -3gamma (smallest). Like nectin-1 and -2, nectin-3alpha consists of three extracellular immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic region with the C-terminal consensus motif for binding to the PDZ domain. Nectin-3alpha formed a cis-homo-dimer and showed Ca(2+)-independent trans-homo-interaction to cause homophilic cell-cell adhesion. Nectin-3alpha furthermore showed trans-hetero-interaction with nectin-1 or -2 but did not form a cis-hetero-dimer with nectin-1 or -2. Nectin-1 did not show trans-hetero-interaction with nectin-2. The affinity of trans-hetero-interaction of nectin-3alpha with nectin-1 or -2 was higher than that of trans-homo-interaction of nectin-1, -2, or -3alpha. Nectin-2 and -3 were ubiquitously expressed, whereas nectin-1 was abundantly expressed in brain. Nectin-3alpha was colocalized with nectin-2 at cadherin-based AJs and interacted with afadin. These results indicate that the nectin family consists of at least three members, nectin-1, -2, and -3, all of which show homophilic and heterophilic cell-cell adhesion activities and are localized at cadherin-based AJs.

Del(X)(p21.1) in a mother and two daughters: genotype-phenotype correlation of Turner features

We report a mother and two daughters with partial Xp monosomy. Clinical assessment for Turner phenotype revealed that the three females manifested low-normal to mild short stature (-1.6 to approximately -2.3 SD) and variable degrees of skeletal features, such as cubitus valgus, short 4th matacarpals, and Madelung deformity, but no soft tissue or visceral anomalies or gonadal dysfunction. Cytogenetic studies for lymphocytes showed that the karyotype was 45,X[3]/46,X,del(X)(p21.1)[27] in the mother and non-mosaic 46,X,del(X)(p21.1) in the two daughters. Fluorescence in situ hybridization and microsatellite analyses for 19 loci/regions on the X chromosome demonstrated that the del(Xp) chromosome was missing SHOX and had the breakpoint between DMD and CYBB. The results are consistent with the recently proposed notion that haploinsufficiency of SHOX results in not only short stature, but also Turner skeletal features in association with maturational effects of gonadal estrogens. The lack of soft tissue or visceral anomalies suggests the presence of the putative lymphogenic gene on the del(Xp) chromosome; the preservation of ovarian function appears to be compatible with meiotic pairing failure being relatively mild.

Identification of novel human GH-1 gene polymorphisms that are associated with growth hormone secretion and height

Height, which is partially determined by GH secretion, is genetically influenced. The purpose of this study was to identify polymorphisms in the GH-1 gene, which are associated with altered GH production. The subjects included prepubertal short children with GH insufficiency without gross pituitary abnormalities (n = 43), short children with normal GH secretion (n = 46), and normal adults (n = 294). A polymorphism in intron 4 (P-1, A or T at base 1663) was identified. Two additional polymorphic sites (P-2, T or G at base 218, and P-3, G or T at base 439) in the promoter region of the GH-1 gene were also identified and matched with the P-1 polymorphism (A or T, respectively) in more than 90% of the subjects. P-1, P-2, and P-3 were considered to be associated with GH production, and the results of P-2 are explained as a representative in this abstract. For example, the allele frequency of T at P-2 in prepubertal short children with GH insufficiency without gross pituitary abnormalities (58.1%) was significantly different from that in short children with normal GH secretion and normal adults (37.0% and 43.5%, respectively; P < 0.001). Furthermore, significant differences were observed in maximal GH peaks in provocative tests (11.1 vs. 18.2 ng/mL, P = 0.006), insulin-like growth factor I SD scores (SDS) (-2.4 vs. -0.8, P < 0.0001), and height (Ht) SDS (-3.7 vs. -3.0, P = 0/001) in children with the T/T or G/G genotypes at P-2, respectively. In the entire study group, significant differences in insulin-like growth factor SDS (T/T, -0.9; G/G, -0.2; P = 0.0009) and Ht SDS (T/T, -1.0; G/G, -0.4; P = 0.022) were observed between the T/T and G/G genotypes at P-2. These data indicate that GH secretion is partially determined by polymorphisms in the GH-1 gene, which explain some of the variations in GH secretion and Ht.

Enhanced cytotoxic effect of Ara-C by low intensity ultrasound to HL-60 cells

A clonogenic assay was tested in order to determine the effects of low intensity ultrasound on HL-60 cells in the presence of cytosine arabinoside (Ara-C). HL-60 cells were exposed to ultrasound at an intensity of 0.3 W/cm2 (48 kHz). Cells were then cultured for 8 days and the number of colonies was statistically analyzed (ANOVA). Ultrasound exposure alone for 120 s resulted in no significant decrease of colonies compared to non-treated cells (P0 = 0.1426). Significant differences (P0 < 0.005) were obtained between ultrasound treated and untreated cells in the presence of various concentrations of Ara-C (2 x 10(-9), 1 x 10(-8), 2 x 10(-8), 5 x 10(-8), 1 x 10(-7) M). Morphological evaluation of ultrasound irradiated cells with scanning electron microscopy showed minor disruption of cell surface and disappearance of microvilli. These observations suggests that low intensity ultrasound altered the cell membrane thus resulting in change in Ara-C uptake into HL-60 cells.

Potent effects of novel anti-platelet aggregatory cilostamide analogues on recombinant cyclic nucleotide phosphodiesterase isozyme activity

The inhibitory potential of novel anti-platelet aggregatory cilostamide analogues on phosphodiesterase (PDE) isozyme activities was investigated with recombinant PDE isozymes expressed in a baculovirus/ Sf9 expression system. The recombinant enzymes (PDE1-PDE5 and PDE7) showed Km values and sensitivities to selective inhibitors similar to those reported previously for native enzymes purified from tissues. The cyclooctylurea derivative OPC-33540 (6-[3-[3-cyclooctyl-3-[(1R*,2R*)-2-hydroxycyclohexyl]ureido]-propoxy]-2(1H)-quinolinone) inhibited recombinant PDE3A (IC50 = 0.32 nM) more potently and selectively than the classical PDE3 inhibitors cilostamide, cilostazol, milrinone, and amrinone. The cyclopropylurea derivative OPC-33509 [(-)-6-[3-[3-cyclopropyl-3-[(1R,2R)-2-hydroxycyclohexyl]ureido]-propoxy]-2(1H)-quinolinone] was less potent (IC50 = 0.10 microM) than OPC-33540, demonstrating that the cyclooctyl moiety was important for a potent inhibitory effect. In platelets, OPC-33540 potentiated cyclic AMP accumulation concentration-dependently in both the absence and the presence of 3 nM prostaglandin E1 (PGE1) (doubling concentrations: 32.5 and 6.2 nM, respectively). OPC-33540 inhibited thrombin-induced platelet aggregation potently (Ic50 = 27.8 nM). The anti-platelet aggregation effect also was stimulated in the presence of 3 nM PGE1 (IC50 = 6.0 nM). There was a good correlation between the IC50 values of PDE3 inhibitors in this study for recombinant PDE3A activity and their IC50 values for thrombin-induced platelet aggregation (r = 0.998). These data demonstrated that OPC-33540 is a highly selective and potent PDE3 inhibitor and a useful probe for identification of the intracellular functions of PDE3.

Interaction of nectin with afadin is necessary for its clustering at cell-cell contact sites but not for its cis dimerization or trans interaction

We have recently found a novel functional unit of cell-cell adhesion at cadherin-based adherens junctions, consisting of at least nectin, a homophilic cell adhesion molecule, and afadin, an actin filament-binding protein, which connects nectin to the actin cytoskeleton. Here we studied a mechanism of cell-cell adhesion of the nectin-afadin system by use of a cadherin-deficient L cell line stably expressing the intact form of mouse nectin-2alpha, a truncated form of nectin-2alpha incapable of interacting with afadin (nectin-2alpha-DeltaC), or a point-mutated form of nectin-2alpha capable of interacting with afadin and a cadherin-expressing EL cell line, which transiently expressed the point-mutated form of nectin-2alpha. We found that the interaction of nectin-2alpha with afadin was necessary for their clustering at cell-cell contact sites. However, nectin-2alpha-DeltaC showed cis dimerization and trans interaction, both of which did not require the interaction of nectin-2alpha with afadin. We have previously shown in EL cells that the interaction of nectin-1 with afadin is necessary for its recruitment to adherens junctions. We found that the trans interaction of nectin-2alpha was furthermore necessary for this recruitment. On the basis of these observations, we propose a model for the mechanism of cell-cell adhesion of nectin and roles of afadin in this mechanism.

Genetic analysis of Japanese patients with persistent hyperinsulinemic hypoglycemia of infancy: nucleotide-binding fold-2 mutation impairs cooperative binding of adenine nucleotides to sulfonylurea receptor 1

To elucidate the genetic etiology of persistent hyperinsulinemic hypoglycemia of infancy (PHHI) in the Japanese population, we conducted a polymerase chain reaction-single-strand conformation polymorphism analysis of the sulfonylurea receptor 1 (SUR1) and Kir6.2 genes in 17 Japanese PHHI patients, including a pair of siblings from a consanguineous family. We also analyzed the glutamate dehydrogenase gene for the exons encoding an allosteric regulatory domain of the enzyme. In the SUR1 gene, we identified one frameshift (I446fsdelT) and two missense (R1420C, R1436Q) mutations. None of these mutations were found in control Japanese subjects. Siblings homozygous for the R1420C mutation had a mild form, whereas two patients heterozygous for the I446fsdelT and R1436Q mutations, respectively, exhibited a severe form of PHHI. Functional consequences of these mutations on K(ATP) function were evaluated using 86Rb+ efflux studies in COS-7 cells. SUR1-446fsdelT and SUR1-1436Q did not form a functional K(ATP). Western blot analysis after transient expression in COS-7 cells revealed the expression of SUR1-1436Q protein to be markedly reduced, suggesting SUR1-1436Q to be unstable in these cells. K(ATP)(SUR1-1420C) showed reduced responses to metabolic inhibition by oligomycin and 2-deoxyglucose. K(ATP) channels are under complex regulation by intracellular ATP and ADP. ATP both inhibits and activates these channels. The inhibition is probably mediated through direct ATP interaction with a pore-forming subunit Kir6.2, whereas the activation is likely to be through a regulatory subunit SUR1. There is a cooperative regulation of ATP and ADP binding to SUR1, and this cooperativity may be involved in regulating the K(ATP) channel. In SUR1-1420C, high-affinity binding of ATP to the nucleotide-binding fold (NBF)-1 was indistinguishable from that of wild-type SUR1. However, stabilization of ATP binding to NBF-1 by MgATP or MgADP was impaired, suggesting that this defect may account for impaired K(ATP)(SUR1-1420C) function. This is the first direct biochemical evidence that the cooperativity of nucleotide binding to SUR1 is impaired in a SUR1 mutant causing PHHI. No mutations were identified in the Kir6.2 and glutamate dehydrogenase genes. The genetic etiology of PHHI appears to be heterogeneous. SUR1 mutations may account for no more than 20% of PHHI cases in Japanese patients. Mutations of Kir6.2 and glutamate dehydrogenase genes are likely to be even less common.

Melanoma chondroitin sulphate proteoglycan regulates cell spreading through Cdc42, Ack-1 and p130cas

Melanoma chondroitin sulphate proteoglycan (MCSP) is a cell-surface antigen that has been implicated in the growth and invasion of melanoma tumours. Although this antigen is expressed early in melanoma progression, its biological function is unknown. MCSP can stimulate the integrin-alpha4 beta1-mediated adhesion and spreading of melanoma cells. Here we show that stimulated MCSP recruits tyrosine-phosphorylated p130 cas, an adaptor protein important in tumour cell motility and invasion. MCSP stimulation also results in a pronounced activation and recruitment of the Rho-family GTPase Cdc42. MCSP-induced spreading of melanoma cells is dependent upon active Cdc42, a Cdc42-associated tyrosine kinase (Ack-1) and tyrosine phosphorylation of p130cas. Furthermore, vectors inhibiting Ack-1 or Cdc42 expression and/or function abrogate MCSP-induced tyrosine phosphorylation and recruitment of p130cas. Our findings indicate that MCSP may modify tumour growth or invasion by a unique signal-transduction pathway that links Cdc42 activation to downstream tyrosine phosphorylation and subsequent cytoskeletal reorganization.

Maitotoxin-induced calcium influx in erythrocyte ghosts and rat glioma C6 cells, and blockade by gangliosides and other membrane lipids

Maitotoxin (MTX) at 0.3 nM elicited a 10-20-fold increase in the level of Ca(2+) influx in rat glioma C6 cells. At higher doses (3-30 nM), MTX induced marked Ca(2+) influx in human erythrocyte ghosts when monitored with the fluorescent dye Fura-2. Although the ghosts were not as susceptible to MTX as intact erythrocytes or other cell lines, Fura-2 experiments under various conditions suggested that the MTX-induced entry of ions into the ghosts was mediated by a mechanism similar to that reported for cells or tissues. These ghosts are the simplest system known to be sensitive to MTX and thus may be suitable for research on the direct action of MTX. Gangliosides GM1 and GM3, glycosphingolipids which have a sialic acid residue, strongly inhibited MTX-induced Ca(2+) influx in C6 cells, while the inhibitory action by asialo-GM1, which lacks a sialic acid residue, was somewhat weaker. Their inhibitory potencies were in the following order: GM1 (IC(50) approximately 2 microM) > GM3 (IC(50) approximately 5 microM) > asialo-GM1 (IC(50) approximately 20 microM). GM1 (3 microM) completely blocked MTX (30 nM)-induced Ca(2+) influx in human erythrocyte ghosts. When C6 cells were pretreated with tunicamycin, an antibiotic which inhibits N-linked glycosylation, or concanavalin A, a lectin which exhibits a high affinity for cell-surface oligosaccharides, MTX-induced Ca(2+) influx was significantly potentiated. This suggests that removal of oligosaccharides from the cell surface by tunicamycin or capping of sugar chains on plasma membranes by concanavalin A can potentiate the action of MTX.

[Application of ultrasound energy as a new drug delivery system]

Ultrasound is frequently used in medicine for diagnostic purposes. Recently, there have been numerous reports on application of ultrasound energy for controlling drug release or targeting. This new concept of therapeutic ultrasound combined with drugs has induced excitement in various areas. Ultrasound energy can enhance effects of thrombolytic agents as urokinase. Ultrasound emitting catheters are currently being developed for cardiovascular diseases. Device with ultrasound transducers implanted in transdermal drug patches are also being evaluated for possible delivery of insulin through the skin. Chemical activation of drugs by ultrasound energy for treatment of cancers is another new field recently termed as "Sonodynamic Therapy". Various examples of application of ultrasound for drug delivery systems are discussed.

Mechanism of hemolysis and erythrocyte transformation caused by lipogrammistin-A, a lipophilic and acylated cyclic polyamine from the skin secretion of soapfishes (Grammistidae)

The mechanism of hemolysis and erythrocyte transformation caused by lipogrammistin-A (LGA), a lipophilic and acylated cyclic polyamine from the skin secretion of soapfishes (Grammistidae), was investigated. The dependency of hemolysis on the erythrocyte concentration indicated that the amount of membrane-bound LGA required for 50% hemolysis is about 13% of the total phospholipids in erythrocytes on a molar basis. A synthetic analogue which lacked a long alkyl chain exhibited much less activity, suggesting that the alkyl chain is important for membrane-binding. In addition, microscopic observations showed that LGA elicited the invagination of erythrocytes at sublytic concentrations, which makes LGA one of the most potent agents with this transforming activity known to date. Its protonated secondary amino group is responsible for the unequal distribution of LGA in the inner leaflet of the lipid bilayer, which leads to invagination, since acetylation at the amino group markedly reduced the invagination activity. Furthermore, the size of LGA-induced lesions on erythrocyte membrane was estimated to be 7-29 A based on osmotic protection experiments, where the external addition of isotonic molecules in this size range gradually increased the effective dose of LGA. Based on these lines of evidence, the mode of LGA action on erythrocytes is deduced to be as follows. First, LGA molecules bind to erythrocyte membrane by lipophilicity. Second, the molecules accumulate in the inner leaflet of the lipid bilayer by interaction of their cationic ammonium groups with acidic residues of membrane lipid in the inner surface. This uneven distribution of LGA distorts the bilayer structure, and results in a change in cell shape and consequent small lesions. Third, small solutes permeate through the lesions, which induces an osmotic change across the membrane, which leads to colloid-osmotic rupture. This mode of action of LGA on erythrocytes accompanied by cell invagination is the first reported example for natural defense substances.

Pharmacokinetics and metabolic effects of high-dose growth hormone administration in healthy adult men

To evaluate pharmacokinetics of growth hormone (GH) and its effects on IGF-I, glucose, insulin, nonesterified fatty acid (NEFA) and triglyceride (TG), fifteen Japanese healthy adult male volunteers (20-27 years old) were studied. The subjects were divided into three groups, and received with a single s.c. injection of 0.075, 0.15 and 0.30 IU/kg of GH, respectively. The subjects assigned to receive 0.30 IU/kg were administered for additional 6 days. After a single administration of GH, Cmax and AUC of GH were increased in a dose-dependent manner. There was a significant positive correlation between the AUC and the T1/2 (r=0.516, P<0.05). Total body clearance was significantly greater in 0.075 IU/kg group than the other groups and showed a significant negative correlation with Cmax (r=-0.694, P<0.005) and AUC (r=-0.723, P<0.005). After a single administration of each dose, serum IGF-I concentrations were increased gradually. In the repeated administered group (0.30 IU/kg), IGF-I concentrations almost reached a plateau at a significantly high level four days after the start of administration and remained at a high level (786-405.4 ng/ml) until day 8. There was no significant difference in diurnal change of blood glucose and serum insulin after a single administration of GH among three groups. In the 0.3 U/kg group, there was no significant difference in diurnal change of blood glucose between day 1 and day 7, but serum insulin level was significantly higher in day 7 than in day 1 (P<0.01). Serum concentrations of NEFA were increased over time after administration in all subjects administered once or repeatedly. TG concentrations showed no changes after single administration of each dose level, but were significantly increased on day 7 in the subjects repeatedly treated with 0.30 IU/kg/day. This effect is speculated to be caused by high dose GH treatment. The above findings demonstrated that higher GH dose significantly influences on carbohydrate and lipid metabolism. It remains necessary to elucidate what kinds of effects of the long-lasting increased levels of insulin and triglyceride, even if reversible, would have on glucose and lipid metabolism.

[Anesthetic management for carotid and coronary artery surgery--concomitant versus two stage operation]

We reviewed the anesthetic management of 16 patients with concomitant severe coronary and carotid artery diseases. Eight patients underwent concomitant operations of coronary artery bypass graft and carotid endarterectomy, while the other 8 patients underwent two stage operation. Candidates for concomitant operations had unstable angina or serious coronary disease such as three vessel disease or severe stenosis of LMT. In comparison, most of patients undergoing two stage operation had symptomatic or occlusive carotid disease. In all cases, anesthesia was maintained with fentanyl and midazolam and the perfusion pressure during cardiopulmonary bypass was maintained above 70 mmHg. Some patients received thiopental or propofol for brain protection. The concomitant operations required much more transfusion and longer operation time than two stage operation. In addition, several cases of the concomitant operation needed intra-aortic balloon pumping or high dose of catecholamines. Indications for concomitant operation or two stage operation have to be determined through discussion among anesthesiologist, neurovascular as well as cardiovascular surgeons.

Cas-L is required for beta 1 integrin-mediated costimulation in human Tcells

Beta 1 integrins provide a costimulus for TCR/CD3-driven T cell activation and IL-2 production in human peripheral T cells. However, this beta 1 integrin-mediated costimulation is impaired in a human T lymphoblastic line, Jurkat. We studied the molecular basis of this impaired costimulation and found that Cas-L, a 105-kDa docking protein, is marginally expressed in Jurkat T cells, whereas Cas-L is well expressed in peripheral T cells. Cas-L is a binding protein and a substrate for focal adhesion kinase and is tyrosine phosphorylated by beta 1 integrin stimulation. We here show that the transfection of wild-type Cas-L in Jurkat T cells restores beta 1 integrin-mediated costimulation. However, Cas-L transfection had no effect on CD28-mediated costimulation, indicating that Cas-L is specifically involved in the beta 1 integrin-mediated signaling pathway. Furthermore, transfection of the Cas-L Delta SH3 mutant failed to restore beta 1 integrin-mediated costimulation in Jurkat cells. Cas-L Delta SH3 mutant lacks the binding site for focal adhesion kinase and is not tyrosine phosphorylated after beta 1 integrin stimulation. These findings strongly suggest that the tyrosine phosphorylation of Cas-L plays a key role in the signal transduction in the beta 1 integrin-mediated T cell costimulation.

Recent status in the occurrence of leukemia in growth hormone-treated patients in Japan. GH Treatment Study Committee of the Foundation for Growth Science, Japan

The Foundation for Growth Science in Japan has monitored the safety and efficacy of GH treatment in GH-deficient patients since 1975. Data were collected from more than 32,000 patients up to December 31, 1997. New leukemia was observed in 14 patients and myelodysplastic syndrome (MDS) in one patient. The types of leukemia were acute lymphocytic leukemia (n = 6; 40%), acute myelocytic leukemia or MDS (n = 7; 47%), and chronic myelocytic leukemia (n = 2; 13%). Leukemia developed in 9 patients during GH treatment and in 6 after the cessation of GH treatment. Six patients had known risk factors for leukemia, such as Fanconi's anemia and previous radiation or chemotherapy. Patient-years of GH therapy was defined as the time from the first dose of GH to the date of the last visit during GH therapy, and patient-years of risk was defined as the time from the first dose of GH to December 31, 1997. The incidence of leukemia of patient-years of GH therapy and patient-years of risk in GH-treated patients without risk factors was 3.0/100,000 and 3.9/100,000, respectively, a figure similar to the incidence in the general population aged 0-15 yr. We conclude that the incidence of leukemia in GH-treated patients without risk factors is not greater than that in the general population aged 0-15 yr, and a possible increased occurrence of leukemia with GH treatment appears to be limited to patients with risk factors.

A cell-autonomous requirement for CXCR4 in long-term lymphoid and myeloid reconstitution

Mice lacking the chemokine stromal cell-derived factor/pre-B cell growth stimulating factor or its primary physiological receptor CXCR4 revealed defects in B lymphopoiesis and bone marrow myelopoiesis during embryogenesis. We show here that adoptive transfer experiments reveal a deficiency in long-term lymphoid and myeloid repopulation in adult bone marrow by CXCR4-/- fetal liver cells, although stromal cell-derived factor/pre-B cell growth stimulating factor-/- fetal liver cells yield normal multilineage reconstitution. These findings indicate that CXCR4 is required cell autonomously for lymphoid and myeloid repopulation in bone marrow. In addition, CXCR4-/- fetal liver cells generated much more severely reduced numbers of B cells relative to other lineages in bone marrow. Furthermore, the repopulation of c-kit+ Sca-1(+) linlow/- cells by CXCR4-/- fetal liver cells was less affected compared with c-kit+ Sca-1(-) linlow/- cells. By previous studies, it has been shown that c-kit+ Sca-1(+) linlow/- cells are highly purified primitive hematopoietic progenitors and that c-kit+ Sca-1(-) linlow/- cells are more committed hematopoietic progenitors in mice. Thus, CXCR4 may play an essential role in generation and/or expansion of early hematopoietic progenitors within bone marrow.