A new ceramide with a novel branched-chain fatty acid isolated from the epiphytic dinoflagellate coolia monotis

From the dinoflagellate Coolia monotis, a new ceramide (1) bearing a 2-hydroxy-15-methyl-3-octadecenoyl moiety was isolated as a cellular constituent. The structure, including the partial absolute configuration, was elucidated as 1 on the basis of the 2D NMR of 1, and chiral HPLC and CD examinations with benzoyl derivatives of its degradation products. To our knowledge, this is the first example, from natural sources, of a C18 fatty acid with a methyl group substituted at a C15 carbon.

In vivo regulation of cyclin A/Cdc2 and cyclin B/Cdc2 through meiotic and early cleavage cycles in starfish

In starfish, fertilization occurs naturally at late meiosis I. In the absence of fertilization, however, oocytes complete meiosis I and II, resulting in mature eggs arrested at the pronucleus stage, which are still fertilizable. In this study, we isolated cDNAs of starfish cyclin A and Cdc2, and monitored extensively the cell cycle dynamics of cyclin A and cyclin B levels and their associated Cdc2 kinase activity, Tyr phosphorylation of Cdc2, and Cdc25 phosphorylation states throughout meiotic and early embryonic cleavage cycles in vivo. In meiosis I, cyclin A was undetectable and cyclin B/Cdc2 alone exhibited histone H1 kinase activity, while thereafter both cyclin A/Cdc2 and cyclin B/Cdc2 kinase activity oscillated along with the cell cycle. Cyclin B-, but not cyclin A-, associated Cdc2 was subjected to regulation via Tyr phosphorylation, and phosphorylation states of Cdc25 correlated with cyclin B/Cdc2 kinase activity with some exceptions. Between meiosis I and II and at the pronucleus stage, cyclin A and B levels remained low, Cdc2 Tyr phosphorylation was undetectable, and Cdc25 remained phosphorylated depending on MAP kinase activity, showing a good correlation between these two stages. Upon fertilization of mature eggs, Cdc2 Tyr phosphorylation reappeared and Cdc25 was dephosphorylated. In the first cleavage cycle, under conditions which prevented Cdc25 activity, cyclin A/Cdc2 was activated with a normal time course and then cyclin B/Cdc2 was activated with a significant delay, resulting in the delayed completion of M-phase. Thus, in contrast to meiosis I, both cyclin A and cyclin B appear to be involved in the embryonic cleavage cycles. We propose that regulation of cyclin A/Cdc2 and cyclin B/Cdc2 is characteristic of meiotic and early cleavage cycles.

T cell receptor-mediated tyrosine phosphorylation of Cas-L, a 105-kDa Crk-associated substrate-related protein, and its association of Crk and C3G

Cas-L (pp105), a Crk-associated substrate (p130(Cas))-related protein, was first identified as a 105-kDa protein that is tyrosine-phosphorylated following beta1 integrin cross-linking in T cells. Cas-L contains possible multiple binding sites for the Src homology (SH) 2 domains of various signaling molecules, and appears to be involved in signal transduction through phosphorylated tyrosine-mediated protein-protein interaction. Since Cas-L is preferentially expressed in lymphocytes, it is conceivable that Cas-L plays an important role in lymphocyte-specific signals. Here, we show the involvement of Cas-L in the T cell receptor (TCR)/CD3 signaling pathway. Cas-L is transiently phosphorylated following CD3 cross-linking, and tyrosine-phosphorylated Cas-L binds to Crk and C3G. Furthermore, a Cas-L mutant that lacks the SH3 domain, the binding site for focal adhesion kinase (FAK), is also tyrosine-phosphorylated upon CD3 cross-linking, but not upon beta1 integrin crosslinking, suggesting that FAK is not involved in CD3-dependent Cas-L phosphorylation. Taken together, the present study indicates a novel signaling pathway mediated by tyrosine-phosphorylated Cas-L upon the TCR/CD3 stimulation.

[A successful perioperative anticoagulation therapy and monitoring of a patient with hereditary plasminogen abnormality undergoing aortic valve replacement]

During perioperative period, plasminogen abnormality can result in unusual or unexplained clotting that occurs spontaneously or after minor trauma. However, there has been no report on perioperative anticoagulation therapy and monitoring in patients with hereditary plasminogen abnormality undergoing cardiac surgery. We performed a successful perioperative anticoagulation therapy and monitoring of a patient with hereditary plasminogen abnormality undergoing cardiac surgery. A 48-year-old male patient with severe aortic valve stenosis, who had had no episode of thrombosis, was scheduled for aortic valve replacement Preoperative laboratory screenings detected his abnormal plasminogen activity (7.6% normal), and he was diagnosed as hereditary plasminogen abnormality. Anesthetic course was uneventful until the initiation of cardiopulmonary bypass (CPB). During CPB, heparin level was monitored every 30 minutes by Hepcon/HMS (Medtronic Hemotec, Parker, CO). No thrombus was observed in the CPB circuit. Plasminogen activity, fibrin degradation products (FDP) and D-dimer were not elevated during perioperative period. Protamine dosage was determined by protamine titration method, and protamine was administrated after the termination of CPB. No major bleeding was observed after protamine administration. When the patient was admitted to ICU, anticoagulation therapy was started immediately. During perioperative period, no episode suggesting thrombosis was observed. In conclusion, we consider that this successful anticoagulation therapy and monitoring during CPB has been achieved by use of Hepcon/HMS.

[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.

Clinical characteristics of children with hypoparathyroidism due to 22q11.2 microdeletion

The phenotypes of chromosomal 22q11.2 microdeletion are quite variable among individuals and hypoparathyroidism (HP) constitutes a definite portion of the clinical spectrum. For the correct diagnosis and pertinent follow up of the HP children due to del22q11.2, we tried to delineate the clinical characteristics of such patients. By employing fluorescence in situ hybridization (FISH) to all the patients diagnosed as HP in our clinic, ten possessed the 22q11.2 microdeletion. Among them, the incidence of cardiac defect (5/10), recurrent infection (1/10) and cleft palate (1/10) was modest. Additionally, seven of them had been diagnosed as HP during the infantile period, when their facial abnormality and intellectual problem had not become evident. Notably, two patients were complicated by Graves disease, while the association of idiopathic thrombocytopenic purpura was also observed in two girls.

CONCLUSION

HP due to del22q11.2 may be misdiagnosed as idiopathic, especially in an infant who lacks apparent complications like cardiac anomaly. They should be closely followed up for auto-immune complications.

[A case of male dysgenetic pseudohermaphroditism detected by the rapid growth of phallus]

A case of male dysgenetic pseudohermaphroditism detected by the rapid growth of phallus is reported. A 10-year-old girl with rapid growth of a phallus during the past 6 months was referred to our clinic. Physical examination revealed a normally located urethral meatus and introitus with a 1.5 cm x 4 cm phallus. Radiographic studies revealed a vagina, uterus and fallopian tube-like structures. Karyotype was a mosaicism with 46, XY (71.5%), 45, X (26%), and others (2.5%). Bilateral gonads were dysgenetic testicular tissue with gonadoblastoma. Focal dysgerminoma was developed on the left side. Bilateral gonadectomy and feminizing phalloplasty were performed.

Correlation of the epitopes defined by anti-CD26 mAbs and CD26 function

To clarify the different anti-CD26 mAbs corresponding different functions of CD26, the correlation of the epitopes defined by anti-CD26 mAbs and the functions of CD26 have been studied. Using truncated, human-rat CD26 swap mutants and cross-blocking studies, 13 anti-CD26 mAbs were divided into 5 separate groups. These 5 epitopes were localized between the 1-247th, 248-358th, 359-449th (closer to the 359th amino acid), 450-577th and 359 653th amino acid regions. MAbs against two of these five epitopes, the 248-358th and 359-449th amino acid regions, were associated with inducing modulation of CD26 and T-cell costimulation through the CD3 pathway. Furthermore, mAbs against one of these epitopes, the 359-449th amino acid region, appeared to encompass the ADA binding domain. Analysing the avidity of each mAb to the CD26 molecule using DPPIV enzymatic activity as an indicator, we found that the function of CD26 had little correlation with the avidity of anti-CD26 mAbs, suggesting that distinct epitopes defined by anti-CD26 mAbs appeared to be associated with different functions of CD26. These results will be very useful in the further definition of the functional domains of CD26.

Inhibition of maitotoxin-induced Ca2+ influx in rat glioma C6 cells by brevetoxins and synthetic fragments of maitotoxin

45Ca2+ influx in rat glioma C6 cells induced by 0.3 nM maitotoxin (MTX) was markedly inhibited by brevetoxin A (PbTx1) and brevetoxin B (PbTx2), with EC50 values of 16 and 13 microM, respectively. This inhibition was observed immediately after addition of MTX when monitored with fura-2, which suggests that PbTx2 directly blocks the action of MTX. This blockade by PbTx2 was not affected by tetrodotoxin, which excludes the involvement of voltage-sensitive sodium channels. The depolarizing effects of these brevetoxins were also not a likely cause of this inhibition, because melittin, a channel-forming peptide, did not significantly block MTX-induced 45Ca2+ influx. Instead, this inhibition was thought to be mediated by blockade of an MTX-binding site by the brevetoxins, based on the fact that these toxins, particularly PbTx2, closely mimic the partial structure of MTX. Synthetic fragments of MTX corresponding to the hydrophilic EF-GH rings (200 microM) and LM-NO rings (500 microM) of MTX significantly reduced MTX-elicited Ca2+ influx. The observation that the effects of MTX were inhibited by structural mimics of both its hydrophobic and hydrophilic portions implies that both portions of the MTX molecule recognize its target.

Determination of adenosine deaminase binding domain on CD26 and its immunoregulatory effect on T cell activation

CD26, a 110-kDa cell surface glycoprotein, exhibits dipeptidyl peptidase IV enzyme activity and plays an important role in T cell costimulation. In the present study, we examined both the exact adenosine deaminase (ADA) binding domain on CD26 and the functional consequences of mutated CD26 transfectants that were deficient for cell surface ADA. Using CD26 deletion, human-rat swap, and point mutations, we found that the residues of L340, V341, A342, and R343 on the CD26 molecule were essential amino acids for ADA binding. When these amino acids were mutated and transfected into Jurkat cells, the resultant CD26 transfectants expressed only CD26, not ADA, on the cell surface. The amount of IL-2 produced by wild-type and mutated CD26 transfectants was almost the same following stimulation with anti-CD3 plus PMA. However, the mutated CD26 transfectants were much more sensitive to the inhibitory effect of adenosine on IL-2 production than were the wild CD26 transfectants. These data suggest that ADA on the cell surface does not directly involve T cell activation. Conversely, CD26 alone does not result in modulating the inhibitory effect of adenosine. Only the ADA bound to CD26 on the cell surface was functional and could counteract the inhibitory effect of elevated extracellular adenosine.

Determination of adenosine deaminase binding domain on CD26 and its immunoregulatory effect on T cell activation

CD26, a 110-kDa cell surface glycoprotein, exhibits dipeptidyl peptidase IV enzyme activity and plays an important role in T cell costimulation. In the present study, we examined both the exact adenosine deaminase (ADA) binding domain on CD26 and the functional consequences of mutated CD26 transfectants that were deficient for cell surface ADA. Using CD26 deletion, human-rat swap, and point mutations, we found that the residues of L340, V341, A342, and R343 on the CD26 molecule were essential amino acids for ADA binding. When these amino acids were mutated and transfected into Jurkat cells, the resultant CD26 transfectants expressed only CD26, not ADA, on the cell surface. The amount of IL-2 produced by wild-type and mutated CD26 transfectants was almost the same following stimulation with anti-CD3 plus PMA. However, the mutated CD26 transfectants were much more sensitive to the inhibitory effect of adenosine on IL-2 production than were the wild CD26 transfectants. These data suggest that ADA on the cell surface does not directly involve T cell activation. Conversely, CD26 alone does not result in modulating the inhibitory effect of adenosine. Only the ADA bound to CD26 on the cell surface was functional and could counteract the inhibitory effect of elevated extracellular adenosine.

Synthesis of pavoninin-1, a shark repellent substance, and its structural analogues toward mechanistic studies on their membrane perturbation

Pavoninin-1 (1), which was isolated from a defense secretion of the sole Pardachirus spp. as an ichthyotoxic and a shark repellent principle, and its structural analogue 2 were synthesized, where glycosylation using an 2-azidoglycosyl sulfoxide (10) afforded the corresponding beta-glycoside exclusively in high yield. Introduction of the alpha,beta-unsaturated ketone system in the ring A of 1 was achieved by phenylselenenylation of dihydropavoninin-1 (3) and subsequent oxidative elimination without protection of the hydroxyl groups in the sugar portion. The mode of action of these glycosides was evaluated for their perturbation on phosphatidylcholine liposomal membrane, using the fluorescent dye leakage method. The results revealed that membrane affinity does not parallel membrane perturbation but rather compensates it, and the spatial arrangement of hydrophobic and hydrophilic regions within a molecule is likely to reflect on the difference in potency of action among them.

Altered tyrosine phosphorylation via the very late antigen (VLA)/beta1 integrin stimulation is associated with impaired T-cell signaling through VLA-4 after allogeneic bone marrow transplantation

Our previous study showed that the cross-linking of very late antigen (VLA)/beta1 with anti-CD29 monoclonal antibody (MoAb), or interactions with extracellular matrix (ECM) proteins through VLA/beta1, failed to induce T-cell costimulation via the CD3/T cell receptor (TCR) pathway for over 1 year after allogeneic bone marrow transplantation (allo-BMT), although normal CD29 and CD3 expression was observed after 3 months following allo-BMT. Molecular analysis revealed altered tyrosine phosphorylation of cellular proteins by the solid-phase cross-linking of VLA/beta1 molecules in T cells from patients after allo-BMT. In T cells from early allo-BMT patients (<4 months), various sizes of highly tyrosine phosphorylated proteins were observed as high background even without the stimulation through VLA/beta1 integrin. The high tyrosine phosphorylation pattern gradually disappeared and it was finally returned to normal tyrosine phosphorylation patterns by 2 years after BMT. Interestingly, poor expression of focal adhesion kinase (pp125FAK), a VLA/beta1-mediated signaling molecule, was observed within 1 year after BMT. These results suggest that these molecular defects appear to be implicated in the impaired VLA/beta1-mediated signaling in T cells from patients after allo-BMT, and it could explain, in part, the persistent immunoincompetent state after allo-BMT at least 1 year.

Tyrosine phosphorylation of Crk-associated substrates by focal adhesion kinase. A putative mechanism for the integrin-mediated tyrosine phosphorylation of Crk-associated substrates

Integrin-ligand binding induces the tyrosine phosphorylation of various proteins including focal adhesion kinase (pp125(FAK)) and Crk-associated substrate (Cas). FAK is activated and autophosphorylated by the ligation of integrins, although the substrate of FAK has not been revealed. We show here that p130(Cas) and Cas-L are FAK substrates. FAK directly phosphorylates Cas proteins primarily at the YDYVHL sequence that is conserved among all Cas proteins. Furthermore, the phosphorylated YDYVHL sequence is a binding site for Src family protein-tyrosine kinases, and the recruited Src family kinase phosphorylates the other tyrosine residues within Cas. The Cas-L YDYVHL sequence is phosphorylated upon integrin-ligand binding, and this integrin-mediated tyrosine phosphorylation is inhibited by the cotransfection of the FAK COOH-terminal domain that does not contain a kinase domain. These findings strongly suggest that FAK initiates integrin-mediated tyrosine phosphorylation of Cas proteins; then, Src family tyrosine kinases, which are recruited to phosphorylated Cas and FAK, further phosphorylate Cas proteins.

A small molecule CXCR4 inhibitor that blocks T cell line-tropic HIV-1 infection

Several members of the chemokine receptor family have been shown to function in association with CD4 to permit human immunodeficiency virus type 1 (HIV-1) entry and infection. The CXC chemokine receptor CXCR4/fusin is a receptor for pre-B cell growth stimulating factor (PBSF)/stromal cell-derived factor 1 (SDF-1) and serves as a coreceptor for the entry of T cell line-tropic HIV-1 strains. Thus, the development of CXCR4 antagonists or agonists may be useful in the treatment of HIV-1 infection. T22 ([Tyr5,12,Lys7]-polyphemusin II) is a synthesized peptide that consists of 18 amino acid residues and an analogue of polyphemusin II isolated from the hemocyte debris of American horseshoe crabs (Limulus polyphemus). T22 was found to specifically inhibit the ability of T cell line-tropic HIV-1 to induce cell fusion and infect the cell lines transfected with CXCR4 and CD4 or peripheral blood mononuclear cells. In addition, T22 inhibited Ca2+ mobilization induced by pre-B cell growth stimulating factor (PBSF)/SDF-1 stimulation through CXCR4. Thus, T22 is a small molecule CXCR4 inhibitor that blocks T cell line-tropic HIV-1 entry into target cells.

Follow-up study of children with precocious puberty treated with cyproterone acetate. Ad hoc Committee for CPA

A total of 1840 children and adolescents treated with cyproterone acetate (CPA) to block gonadal function, as a treatment for precocious puberty, short stature and other disorders, were registered to survey for the risk of developing hepatic tumors. Patients responding to follow-up numbered 1552 (85%). The cumulative dose and duration of CPA therapy for boys and girls were 110.4g and 2.6 years, and 122.9 g and 2.8 years, respectively. Among the 1552 patients, five hepatoma cases were found. Four underwent successful surgery and remain alive and well to date. Two of the 5 cases had been given more than 500g, the other 3 more than 1000 g, of CPA. Three had also been given androgens before CPA administration. Although further follow-up is necessary to monitor for the development of adenoma and hepatoma, the risk of developing these tumors among patients to whom limited doses of CPA were administered appears to be negligible.

Prototype therapeutic ultrasound emitting catheter for accelerating thrombolysis

The aim of this study was to evaluate the performance of a new therapeutic ultrasound device for accelerating thrombolysis by urokinase. Artificial thrombi were produced in vitro by Chandler's loop method. Urokinase (240 IU) was added to the artificial thrombi (n = 5) before exposure to ultrasound with the new catheter-delivered device. Ultrasound (1.3 MHz) was applied with an intensity of 0.3 W/cm2 for 60 s. The degree of fibrinolysis was obtained by measurement of thrombus weight and calculated as percentages. Fibrinolysis was compared between control thrombus groups (n = 5) treated with urokinase alone or with ultrasound alone (analysis of variance, P < 0.05). Ultrasound plus urokinase (33.1 +/- 6.1% [mean +/- standard deviation]) was significantly different urokinase alone (12.3 +/- 2.4%) after 15 min of incubation. Ultrasound alone resulted in no fibrinolysis (0.9 +/- 2.5%). Ultrasound energy from the catheter-based device was sufficient to induce acceleration of fibrinolysis with urokinase.

Clinical trials of GH treatment in patients with Turner's syndrome in Japan--a consideration of final height. The Committee for the Treatment of Turner's Syndrome

Clinical trials of human GH (hGH) therapy in Turner's syndrome were started in 1986. Between 1986 and 1990. 362 patients were enrolled; 115 were treated for more than 6 years. The age at the start of treatment ranged from 5 to 18 years (mean 10 years). Fifty-one patients received hGH at a weekly dosage of 0.5 IU/kg and 64 received 1.0 IU/kg by daily s.c. injection. Both treatment groups showed a statistically significant growth increase during the initial 4 years of treatment. The rate of increase in height was significantly greater for the initial 2 years with the high dose than with the low dose. The increases in height over 6 years of treatment (expressed by S.D. score for chronological age) were 1.48 +/- 0.8 with 0.5 IU/kg per week and 1.80 +/- 1.0 with 1.0 IU/kg per week. To date, 260 patients have stopped GH therapy. In 32% of them, the height attained was above the -2 S.D. value for normal girls. In 27%, the growth rate was not sufficient when they stopped treatment. The mean final height (growth rate < or = 1.0 cm/year) of patients treated for more than 6 years was 142.2 +/- 6.5 cm (n = 15) with 0.5 IU/kg per week, and 144.3 +/- 3.9 cm (n = 15) with 1.0 IU/kg per week. The adult height was improved by GH treatment, although final height did not differ statistically between the two dose regimens. No remarkable adverse events occurred during the treatment. These results indicate that hGH treatment improves the final height in patients with Turner's syndrome.

Osteopathia striata, short stature, and characteristic facies: a previously unknown skeletal dysplasia

We report two sporadic cases of a hitherto undescribed skeletal dysplasia with short stature and characteristic facies. The present patients, a 6-year-old girl and a 15-year-old boy, were almost equally affected. Craniofacial anomalies included a sloping forehead, bitemporal bulging, sparse medial eyebrows, a prominent nasal bridge, hypertelorism, proptosis, a beaked nose, hypoplastic alae nasi and a pointed chin. Shallow orbits, short anterior cranial fossae and bitemporal bossing found on skull radiograph corresponded with the facial dysmorphism. Thickening of the dorsum sellae was another hallmark in the skull. Skeletal survey revealed mild osteopenia, interpediculate narrowing of the lumbar spine with short neural arches and, most important, osteopathia striata of the long tubular bones. There was no sclerosis of the craniofacial bones. The clinical and radiological findings in the present patients were overall inconsistent with those of previously known skeletal dysplasias and congenital malformation syndromes, which possess osteopathia striata as a cardinal feature.

CONCLUSION

The unique clinical and radiological constellation of our patients constitutes a hitherto unknown bone dysplasia.

T-stem cell leukemia/lymphoma with both myeloid lineage conversion and T-specific delta recombination

We evaluated retrospectively the clinical and biological characteristics of six patients with CD7+ early T-acute lymphoblastic leukemia and lymphoma (T-ALL/LBL) originating from prothymocyte stage I (pro-T I) or II cells. Patients exhibited mediastinal mass (five of six) and lymphoadenopathy (five of six) but without leukocytosis and circulating blast cells (six of six). All patients achieved a complete remission. All but one had a relapse with a transformation to the mixed type (triphenotype--three cases, biphenotype-two cases) including myeloid features in three patients. The altered phenotypes were myeloperoxidase (MPO)+ (three of five), CD13+ (four of five), CD33+ (three of five) and CD19+ (three of five). The difference for MPO-positivity were observed between the bone marrow (BM)- and lymph node (LN)-blast cells (three of three). On cytogenetic analysis, there is no common abnormality in these patients. Immunomolecular analysis revealed T-cell lineage specific delta gene rearrangements [D delta 2-J delta 1 (five of six) and V delta 1-J delta 1 (one of six)] in all cases. Furthermore, D delta 2-J delta 1 occurred even in the cases with the pro-T I phenotype. Rearrangements of TCR beta, gamma or immunoglobulin heavy chain genes occurred in three patients. The same rearranged band(s) appeared at both diagnosis and relapse, indicating the same originality of the pro-T leukemic cell clone (three of three). We suggest that this type of CD7+ early T-ALL/LBL was transformed from a pro-T I or II cell, such as T-stem cell leukemia/lymphoma, which is a subtype of CD7+ stem cell leukemia as defined by Kurtzberg et al. This study reveals that pro-T I and II cells might be capable of myeloid, T- and B-lymphoid differentiation, and T-cell lineage specific TCR delta recombination occurs.

MAP kinase links the fertilization signal transduction pathway to the G1/S-phase transition in starfish eggs

The mechanism by which fertilization initiates S-phase in the zygote is examined by manipulating the activity of MAP kinase in mature starfish eggs. These unfertilized eggs, which are arrested at G1-phase after the completion of meiosis, have high MAP kinase activity but undetectable cdc2 kinase activity. Either fertilization or inhibition of protein synthesis causes a decrease in MAP kinase activity, which is followed by DNA synthesis. Inactivation of MAP kinase with its specific phosphatase, CL100, initiates DNA synthesis in the absence of fertilization, while constitutive activation of MAP kinase with MEK represses the initiation of DNA synthesis following fertilization. Thus, in unfertilized mature starfish eggs, a capacity for DNA replication is already acquired, but entry into S-phase is negatively regulated by MAP kinase activity that is supported by a continuously synthesized protein(s) but not by cdc2 kinase. Upon fertilization, downregulation of MAP kinase activity is necessary and sufficient for triggering the G1/S-phase transition.