Effect of chitosan implantation on activation of canine macrophages and polymorphonuclear cells after surgical stress

The effect of cotton type chitosan implantation under the skin on the immunological response mediated by macrophages and whole blood was evaluated by chemiluminescence (CL) in dogs. The number of white blood cells was significantly decreased until 120 hr after operation in the control group (p < 0.05), while chitosan implantation increased the number of white blood cells, particularly neutrophils, from 24 to 96 hr after implantation (p < 0.05). The CL response of whole blood in the control group seemed to be reduced at 48 and 96 hr after operation (p < 0.05), but in the chitosan groups it maintained higher activity until 120 hr after implantation (p < 0.05). The macrophage activity measured by CL assay in the control group was markedly decreased from 24 to 120 hr after operation, and that for the 5 mg/kg chitosan group was also decreased at 24 and 48 hr after implantation (p < 0.05), although high activity was observed from 72 to 120 hr after implantation (p < 0.05). Neither 5 mg/kg nor 10 mg/kg chitosan groups showed any reduction in CL response of macrophages after operation, and the 20 mg/kg chitosan group retained high CL response of macrophages until 120 hr after operation (p < 0.05). These findings suggest that chitosan may be an efficacious and useful immunopotentiator for preventation of immunosuppression after surgery.

Epithelioid sarcoma with an 18q aberration

Epithelioid sarcoma is a peculiar soft-tissue neoplasm of uncertain origin, which is characterized by an epithelioid morphology of tumor cells coexpressing epithelial (keratin) and nonepithelial (vimentin) antigens. We herein report a new cytogenetic abnormality with der(22)t(18;22)(q11;p11.2) in a case of epithelioid sarcoma that occurred in the elbow of a 75-year-old man. Histologically, the tumor demonstrated a multinodular proliferation of epithelioid cells, with positive immunostaining for keratin, epithelial membrane antigen (EMA), and vimentin. Cultured tumor cells obtained from fresh surgical materials were frozen in plastic ampules and stocked in a liquid nitrogen freezer. Six years after surgery, the cells were recovered from the freezer and utilized for both morphologic and cytogenetic analyses. These cultured cells both before and after the freezing exhibited essentially the same epithelioid morphology and immunophenotypes as those of the original tumor. A chromosome analysis, together with fluorescence in situ hybridization (FISH), demonstrated a 61-67 modal population, and a characteristic clonal abnormality with der(22)t(18;22)(q11;p11.2). Other clonal abnormalities included numerical (-3, -4, +7, -13, -14, -16, -18, +20, -22) and structural (8p+, 9p+, 12p+, i(21q)) aberrations. Some variant clones also demonstrated i(18q). Since the breakpoint at 18q11 is similar to that reported in synovial sarcoma, this finding may support the presence of a histogenetic relationship between epithelioid sarcoma and synovial sarcoma. Our study thus indicates that the storage of frozen cells is useful for both morphologic and cytogenetic analyses of soft tissue tumors.

An imprinted gene p57KIP2 is mutated in Beckwith-Wiedemann syndrome

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin/Cdk complexes, and is a negative regulator of cell proliferation. The gene encoding p57KIP2 is located at 11p15.5 (ref. 2), a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome, a cancer-predisposing syndrome, making it a tumour-suppressor candidate. Several types of childhood tumours including Wilms' tumour, adrenocortical carcinoma and rhabdomyosarcoma exhibit a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting is involved. Genetic analysis of the Beckwith-Wiedemann syndrome indicated maternal carriers, as well as suggesting a role of genomic imprinting. Previously, we and others demonstrated that p57KIP2 is imprinted and that only the maternal allele is expressed in both mice and humans. Here we describe p57KIP2 mutations in patients with Beckwith-Wiedemann syndrome. Among nine patients we examined, two were heterozygous for different mutations in this gene-a missense mutation in the Cdk inhibitory domain resulting in loss of most of the protein, and a frameshift resulting in disruption of the QT domain. The missense mutation was transmitted from the patient's carrier mother, indicating that the expressed maternal allele was mutant and that the repressed paternal allele was normal. Consequently, little or no active p57KIP2 should exist and this probably causes the overgrowth in this BWS patient.

Short arm of chromosome 1 aberration recurrently found in pigmented villonodular synovitis

Pigmented villonodular synovitis (PVNS) is a relatively uncommon benign lesion that is characterized by diffuse synovial proliferation, mainly occurring in knee joints. Cytogenetic reports about this lesion are few and they describe the presence of numerical and structural chromosome aberrations. We obtained PVNS tissue from the left knee joint of a 53-year-old female, and performed cytogenetic analysis. Fluorescence in situ hybridization (FISH) was also performed by using the formalin fixed, paraffin embedded PVNS tissue. Two seemingly unrelated clones were found: the first clone had structural abnormalities of chromosome 1, 3, and 18, and the second one had trisomy 7 as a sole numerical abnormality. FISH using a chromosome 7 specific alpha-satellite DNA probe revealed that interphase nuclei possessed two or three signals. We describe the clonal aberrations found in a case of PVNS. The deleted lesion of the chromosome 1 (1p10-1p31.3) includes the locus of coagulation factor III gene (1p22-p21), and the coagulation factor V (1q21-q25) locus includes another breakpoint that is 1q25. In addition, recurrent structural abnormalities at the short arm of chromosome 1 have been reported. These facts might play some role in the hemorrhagic tendency and histogenesis of these lesions.

[Long-term patency after the Blalock-Taussig operation--comparison between classic and modified shunts]

There is still a need for Blalock-Taussig shunt (BTS) in some situations involving complex heart diseases. This study demonstrates the long-term patency after shunt procedure in classic and modified BTS of different calibers using cineangiographic evaluation. Between January 1980 and December 1994, 150 patients 236 BTS including classic BTS (cBTS) in 62, modified in 174 procedures (GS: Golaski microknit graft in 112, EPTFE: expanded polytetrafluoroethylene graft in 62). Cineangiographic Evaluation for graft patency and freedom from stenosis (less than 50% in diameter) was performed a mean interval of 35 months after BTS. The five-year patency of cBTS was significantly superior to that of mBTS (EPTFE, p < 0.001). There was a significant superiority of three-year actuarial freedom from graft stenosis in cBTS compared to that after mBTS with GS (p < 0.01) and in mBTS with EPTFE compared to mBTS with GS (p < 0.05). In cases receiving small caliber grafts (4 mm or less), cBTS showed significantly better patency after five years compared to mBTS with GS (p < 0.05) and showed significant advantages in three-year actuarial freedom from graft stenosis compared to that after mBTS (p < 0.05). This study demonstrated the superior patency and freedom from stenosis after cBTS compared to that after mBTS, especially in cases receiving GS grafts. MBTS with GS graft and with small caliber EPTFE grafts could not be expected to maintain freedom from stenosis for three years.

Cationic liposomes enhance retrovirus-mediated multinucleated cell formation and retroviral transduction

A retroviral vector carrying herpes simplex virus thymidine kinase (HSV-TK) gene was introduced into psi 2 packaging cells (psi 2tkn) and XC tumor cells (XCtkn). psi 2tkn, XCtkn and XC cells co-cultured with TK-carrying cells were killed by ganciclovir (GCV) treatment. The growth of XC cells transplanted into nude mice was also suppressed by intratumoral injection of psi 2tkn or XCtkn cells and subsequent GCV administration. In addition, the XC cells cultured with either psi 2tkn cells or cell-free retrovirus suspension formed giant multinucleated cells. The multinucleated cell formation was specific to the combination of XC cells and the retrovirus produced by the psi 2tkn cells. Cationic liposomes enhanced the retrovirus-induced multinucleated cell formation and retroviral transduction. The correlation between the two actions of liposomes suggests that liposomes which enhance multinucleated cell formation are potent enhancers of retroviral transduction.

K252a inhibits the phosphorylation of pRb without changing the levels of G1 cyclins and Cdk2 protein in human hepatoma cells

A protein kinase inhibitor K252a suppressed the growth of HuH7 hepatoma cells and the hyperphosphorylation of retinoblastoma protein (pRb) at late G1 phase of cell cycle. However, K252a treatment did not alter the levels of cyclin D1, cyclin E, cyclin A and Cdk2 protein bound to cyclin E or cyclin A. Therefore, the K252a inhibition of pRb phosphorylation is considered to be brought about probably by inhibiting the action of Cdk-cyclin complex rather than by changing its cellular level. These results also suggest that K252a is a useful tool for investigating the mechanism of phosphorylation of pRb mediated by Cdk-cyclin.

Activation mediated by RP105 but not CD40 makes normal B cells susceptible to anti-IgM-induced apoptosis: a role for Fc receptor coligation

Signals through the B cell antigen receptor lead to a variety of cellular events such as activation, anergy, and apoptosis. B cells select these outcomes to establish and maintain self-tolerance, and to mount adequate antibody responses. However, it is not fully understood how one and the same signal causes such different consequences. In the present study, we have studied the effect of activation signals on the outcome of responses to antigen receptor ligation. Two distinct growth-promoting signals were used to activate B cells. Ligation of either RP105, a newly discovered B cell surface molecule, or the CD40 molecule, drove B cells to proliferate. Resultant blastic cells were then exposed to anti-immunoglobulin M (IgM). Blast cells that had been stimulated with anti-RP105 ceased growing and underwent apoptosis after cross-linking of surface IgM. Coligation of the Fc gamma receptor IIB with surface IgM augmented, rather than aborted, this response. In contrast to RP105-activated B cells, blast cells that had been activated by CD40 ligation were unaltered by anti-IgM. On the other hand, CD40-activated B cells became extremely susceptible to Fas-mediated apoptosis, whereas RP105-activated B cells were much less sensitive. Anti-IgM-induced apoptosis in RP105 blasts was independent of Fas, because it was demonstrable with Fas-deficient MRL-lpr/lpr mice. These results demonstrate that the nature of an initial activation signal has a great influence on the fate of activated B cells after (re)engagement of the antigen receptor. RP105, as well as CD40, may be important in this life/death decision.

Activation of mitogen-activated protein kinases via CD40 is distinct from that stimulated by surface IgM on B cells

CD40 plays critical roles in B cell proliferation and differentiation in response to T cell-dependent antigenic stimulation. It has been suggested that CD40-mediated biological activities are transduced by a CD40 receptor-associated factor, CRAF1 and probably by protein tyrosine kinase Lyn and its substrates, phospholipase C gamma (PLC gamma) and phosphatidylinositol-3 kinase (PI-3 kinase). Here, we describe the novel finding that a mitogen-activated protein kinase (MAPK) extracellular signal-regulated protein kinase (ERK) cascade is involved in CD40 signaling in mouse B cells. Analysis of ERK activities in the B cell lymphoma cell line WEHI 231, which shows an increase in DNA synthesis or arrest of the cell cycle by cross-linking of CD40 or surface IgM (sIgM) cross-linking, respectively, indicated that one of the ERK isoforms, ERK2, was preferentially and rapidly activated after CD40 cross-linking. The CD40-mediated ERK2 activation was comparable to that after sIgM stimulation, although the activity was reduced toward the basal level within several minutes after stimulation. In contrast, ERK1 and ERK2 were activated to a similar extent by sIgM cross-linking, and the activities remained stable for at least 10 min. Furthermore, similar features of differential activation of ERK isoforms were observed in normal resting B cells in CD40 and sIgM signaling. These results suggest divergent regulatory pathways for ERK1 and ERK2 activation, and they support the notion that CD40 signaling may utilize a limited set of elements in the ERK cascade. Co-stimulation of WEHI 231 cells with anti-CD40 mAb rescues the cells from anti-IgM-mediated apoptosis, whereas this co-stimulation resulted in activation of ERK isoforms comparable to that in sIgM stimulation, without a synergistic effect. This result indicates the dominance of ERK activation in sIgM signaling over that of CD40, and it suggests that ERK activation may not be linked to the biological effect that CD40 stimulation in this cell line.

The der(21)t(12;21) chromosome is always formed in a 12;21 translocation associated with childhood acute lymphoblastic leukaemia

We studied 116 patients (93 children and 23 adults) with acute lymphoblastic leukaemia (ALL) using fluorescence in situ hybridization (FISH) with the yeast artificial chromosome (YAC) clone, 964c10, which includes the recently described ETS-like gene, TEL, on 12p13. FISH revealed that nine of the patients had a t(12;21), which had not been previously detected. The nine patients were all children, seven boys and two girls, aged 1-10 years (median 3 years), had an early B immunophenotype, and achieved complete remission, although two of them experienced haematological relapse. In addition to the t(12;21), FISH also revealed that three of the nine had a del(12p) in the other homolog of chromosome 12 or in the der(12) chromosome itself, and that two others had 12p translocations in the other chromosome 12 homolog. Although chromosomal rearrangements associated with the t(12;21) were heterogenous and complex, fusion of the sequences from chromosomes 12 and 21 on the der(21)t(12;21) chromosomes was consistent, suggesting that the TEL-AML1 gene fusion on the der(21) chromosome may be critical in leukaemogenesis and that FISH or reverse transcriptase-polymerase chain reaction (RT-PCR) targeted to the chimaeric sequences on the der(21) will be most useful in detecting the t(12;21) or following a patient with the t(12;21), which is one of the most frequent chromosomal rearrangements in both Caucasian and Asian childhood ALL.

Role of strong anchor residues in the effective binding of 10-mer and 11-mer peptides to HLA-A*2402 molecules

The binding capacity of one-hundred-and-seventy-two 8-mer to 11-mer peptides carrying HLA-A24 anchor residues to HLA-A*2402 molecules was analyzed by using a HLA class I stabilization assay. Most (76. 2%) of these peptides bound to HLA-A*2402 molecules. These results confirmed previous findings that Tyr and Phe at P2 as well as Phe, Trp, Ile, and Leu at the C-terminus were main anchor residues for HLA-A*2402. Tyr at P2 was a stronger anchor residue than Phe, while bulky aromatic hydrophobic residues Phe and Trp at the C-terminus are stronger anchors than aliphatic hydrophobic residues Ile and Leu. These results were also supported by an analysis using a panel of mutated 9-mer peptides at P2 and P9. Taken together, these results suggest that HLA-A*2402 molecules have deep B- and F-pockets because they favor peptides carrying bulky aromatic hydrophobic residues at P2 and the C-terminus. The affinity of 8-mer peptides was significantly lower than that of 9-mer to 11-mer peptides, while there was no difference in affinity between 9-mer, 10-mer, and 11-mer peptides. The affinity of peptides carrying bulky aromatic hydrophobic residues at the C-terminus was higher than that of peptides carrying aliphatic hydrophobic residues in each of the 8-mer to 11-mer peptides, though the greatest difference in affinity was observed in 11-mer peptides. The strong interaction of side chains of these anchor residues with the corresponding pockets may permit the effective binding of 10-mer and 11-mer peptides to HLA-A*2402 molecules.

Genomic reorganization between two sibling yeast species, Saccharomyces bayanus and Saccharomyces cerevisiae

Genomic comparison of two sibling yeast species, Saccharomyces bayanus and Saccharomyces cerevisiae, was performed by Southern blot analysis with various S. cerevisiae gene probes following electrophoretic karyotyping. Fifteen genes on chromosome IV of S. cerevisiae were examined and classified into two groups. Gene probes of CEN4 and TRP1, as well as six other genes located on the left arm of the chromosome hybridized to a 1100-kb chromosome of S. bayanus that is smaller than chromosome IV of S. cerevisiae. On the other hand, probes of seven genes located on the right arm of chromosome IV hybridized to a 1350-kb chromosome that is homeologous to chromosome IV, judging from its size. Two genes located on the left arm of chromosome II hybridized to the 1350-kb chromosome, while four genes on the right arm hybridized to the 1100-kb chromosome. These pieces of evidence indicate that chromosomes II and IV of S. cerevisiae are rearranged into 1350-kb and 1100-kb chromosomes in S. bayanus. Furthermore, it is suggested that chromosome XV is rearranged into two chromosomes (800 and 850 kb in size) in S. bayanus. The translocation points of chromosomes II and IV were delimited using S. cerevisiae prime clone membranes. The results indicated that the translocation points are located close to the FUR4 locus on chromosome II and close to the RAD57 locus on chromosome IV.

Genomic imprinting of human p57KIP2 and its reduced expression in Wilms' tumors

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin complexes, and is a negative regulator of cell proliferation. The gene encoding human p57KIP2 is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome (BWS), a cancer syndrome, making it a tumor suppressor candidate. Several types of childhood tumors including Wilms' tumor, adrenocortical carcinoma and rhabdomyosarcoma display a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting plays an important part. Genetic analysis of the familial BWS has indicated maternal carriers and suggested a role in genomic imprinting. Previously, we demonstrated that p57KIP2 is imprinted in the mouse. Here we describe the genomic imprinting of human p57KIP2 and the reduction of its expression in Wilms' tumors. High resolution mapping locates p57KIP2 in the region responsible for both tumor suppressivity and BWS.

Suppressed expression of phenobarbital-inducible hepatic cytochrome P-450s in Eisai-hyperbilirubinuria rats (EHBR/Eis)

The differential induction of hepatic cytochrome P-450 (P450) was studied in Eisai-hyperbilirubinuria rats (EHBR/Eis). This rat is a mutant that has as high a concentration of bilirubin in the urine as in the plasma. A single administration of trans-stilbene oxide (TSO, 2 mmol/kg), a phenobarbital (PB)-type P450 inducer, did not increase total P450, the CYP2B1/2 or the CYP2C6 in EHBR/Eis liver. TSO was able to induce delta-aminolevulinic acid synthetase and heme oxygenase, rate-limiting enzymes in heme biosynthesis and degradation, respectively, in both EHBR/Eis and Sprague-Dawley rat (SDR), the strain from which EHBR/Eis is derived. TSO also produced similar effects on glutathione depletion and on the activities of other drug-metabolizing enzymes in both strains. A 23-fold increase in CYP2B1/2 mRNA in the SDR liver was observed 24 hr after TSO treatment. In the EHBR/Eis strain, however, TSO increased CYP2B1/2 mRNA only 2-fold. In addition, repeated injection of TSO failed to induce P450 isozymes, CYP2B1/2, CYP2C6 or CYP3A2 in EHBR/Eis. On the other hand, there was essentially no difference in the induced levels of CYP1A1/2 apoprotein and mRNA between twins of SDR and EHBR/Eis livers treated with 3-methylcholanthrene or 1-benzylimidazole. The increased levels of both CYP2B1/2 apoprotein and mRNA from EHBR/Eis liver treated with TSO and 1-benzylimidazole were much smaller (2.5- and 5-fold increases, respectively) than from the SDR liver (17.5- and 15-fold increases, respectively). Although PB expressed CYP2B1/2 apoprotein and mRNA to a similar extent in both homozygous and heterozygous EHBR/Eis livers, CYP3A2 and CYP2C6 were less responsive to PB in homozygous EHBR/Eis. Repeated treatment with TSO induced these isozymes in heterozygote but not in homozygote. These findings suggest that the suppressed expression of PB-inducible P450 isozyme genes in the EHBR/Eis liver may be a general phenomenon associated with PB-type inducers. Therefore, EHBR/Eis may be experimentally useful for studying the mechanism of P450 induction by PB and PB-type inducers.

Characteristics of beta-adrenergic receptors in longitudinal muscle membranes of rat uterus: changes in kinetic properties of the receptor during gestation

Binding characteristics of beta-adrenergic receptors of longitudinal muscle membranes isolated from different stages of pregnant rat myometrium were investigated using [3H]dihydroalprenolol. Between Days 15 and 21 of gestation, the ratio of beta 1- and beta 2-adrenergic receptors of longitudinal membranes was constant. The membranes were found to be predominant in beta 2-adrenergic receptors. The concentration of longitudinal muscle beta-adrenergic receptors increased significantly during the last 7 days of gestation. Kinetic binding studies implied that the affinity of the membrane beta-adrenergic receptors decreased through a slight decrease in the association rate and a large increase in the dissociation rate with progression of pregnancy. A Scatchard plot indicated that longitudinal muscle in beta-adrenergic receptors on Days 15 and 18 constitute a single class of independent sites. By contrast, the dissociation kinetics, the convex downward curvature in a Scatchard plot and a Hill coefficient (h) of less than 1.00 of [3H] DHA binding to beta-receptors of muscle on Day 21 suggested the existence of negatively cooperative multiple binding sites for beta-adrenergic ligand. These results suggest that changes in the dynamics of uterus beta-adrenergic receptors play an important role in the onset of labor.

Embolization for ruptured superior mesenteric artery aneurysms

Superior mesenteric artery (SMA) aneurysms are very uncommon. They are difficult to detect until they rupture and cause hypovolaemic shock. We performed embolization in four cases of aneurysm of branches of the superior mesenteric artery, succeeding in three cases without the need for surgical treatment. In the first case, the aneurysm was excised because of migration of a microcoil into the left hepatic artery. It was not retrieved because sufficient blood flow to the liver was shown on angiography after migration and no ischaemic change of liver was detected on laparotomy. In the second case, the aneurysm arose from the anterior pancreaticoduodenal artery. In the third case, the patient had two SMA aneurysms; one had been resected at surgery, another was revealed on follow-up angiography and embolized with microcoils. The fourth patient had a jejunal artery aneurysm with extravasation; haemostasis was achieved by packing it. In all four cases, no major complications were observed in the clinical course after embolization. Microcoils were considered to be the desirable embolic material, in order to prevent post-therapeutic ischaemic change. Embolization should be the treatment of choice for SMA aneurysms, because it is less invasive and takes less time than surgical treatment.

Renal primitive neuroectodermal tumor: an immunohistochemical and cytogenetic analysis

The cytogenetic and morphologic characteristics of a case with a primitive neuroectodermal tumor (PNET) arising from the left kidney in a 22 year old man are presented. The patient was detected as having a left renal mass with a tumor embolus in the inferior vena cava and multiple pulmonary metastases. A radical nephrectomy with tumor embolectomy of the inferior vena cava, along with a resection of the pulmonary nodules were performed. Histologic examination revealed a dense proliferation of small round cells with many Homer-Wright type rosettes and perivascular pseudorosettes. Immunohistochemically, the tumor cells stained strongly positive for HBA71(p30/32MIC2), a surface glycoprotein specific to PNET and Ewing's sarcoma. In addition, the tumor cells expressed several neural markers (neuron specific enolase, neurofilament, synaptophysin, and Leu-7) and vimentin, while the epithelial, muscular, and lymphocytic markers were negative in the tumor cells. Cytogenetic analysis of cultured tumor cells showed a reciprocal translocation t(11;22)(q24;q12) that is considered to be specific to PNET and Ewing's sarcoma. In conclusion, this case suggested that a karyotyping analysis is a useful diagnostic tool for renal PNET, and it may therefore be utilized to help distinguish between difficult cases of small round cell tumors and Wilms' tumor of the kidney.

Requirement for transglutaminase in progesterone-induced decidualization of human endometrial stromal cells

Differentiation of endometrial stromal cells (decidualization) is essential for embryo implantation and maintenance of pregnancy. By sequential complementary DNA subtractive hybridization, one of the messenger RNAs (mRNA) induced by progesterone in human endometrial stromal cells decidualized in vitro was identified as that of a tissue transglutaminase type II (TGase). TGase mRNA was induced within 6 h after the addition of progesterone to the culture, and the effect was dose dependent. Both the TGase inhibitor monodansylcadaverine and oligodeoxynucleotide complementary to the TGase mRNA inhibited the decidualization, as assessed by PRL production and morphological transformation. Expression of TGase mRNA in human decidua and endometria exposed to high levels of progesterone in vivo was demonstrated by Northern blotting and in situ hybridization. These data suggest that TGase is necessary for the decidualization of human endometrial stromal cells and that clarification of the mechanism of action of TGase will facilitate further insight into the diagnosis and treatment of infertility.

Infrequent mutations of the TP53 gene and no amplification of the MDM2 gene in hepatoblastomas

We have investigated the mutation of the TP53 gene in hepatoblastomas (HBLs) by using polymerase chain reaction-single strand conformation polymorphism and direct sequencing in 38 HBL tumor samples and in two HBL cell lines. We detected the TP53 gene mutation in an anaplastic hepatoblastoma cell line, but no aberration of the TP53 gene (exons 5-9) was found in tumor samples and in the other HBL cell line. The mutation of the cell line was a missense mutation from GAC (asparagine) to CAC (histidine) at codon 281, which was different from the G-to-T transversion of codon 249 that is frequently found in adult hepatocellular carcinomas (HCCs). In addition, we performed Southern blot analysis of the MDM2 gene, but we did not find MDM2 gene amplification in 19 cases tested. Our results suggest that, in contrast to the findings in HCCs in adults, TP53 gene aberrations are not involved in the development or progression of HBLs in children.

[Long QT syndrome]

Romano-Ward syndrome, one of familial long QT syndromes, is an inherited disorder that causes sudden death from cardiac arrhythmias, specifically torsade de pointes and ventricular fibrillation. By linkage analyses, three LQT loci were previously mapped: LQT1 on chromosome 11p15.5, LQT2 on 7q35-36, LQT3 on 3p21-24. It was recently brought to light that LQT2 and LQT3 were caused by mutations of the gene encoding cardiac ion channels. Mutations in HERG on chromosome 7q35-36, encoding potassium channels (Ikr), cause LQT2, and block of Ikr is a known mechanism for drug-induced prolongation of cardiac action potentials, which provides a mechanistic link between LQT2 and certain forms of acquired LQT. Mutations in SCN5A on chromosome 3p21, encoding the human heart voltage-gated sodium-channel alpha-subunit, cause LQT3. Mutant channels show a sustained inward sodium current during membrane depolarization, which explains prolongation of cardiac action potentials.

Mesial temporal lobe epilepsy: clinical features and seizure mechanism

To study the clinical features of mesial temporal lobe epilepsy, 24 cases were selected based on two criteria: (a) the origin of seizure was localized to the mesiotemporal region on phase 2 monitoring, and (b) a class 1 or 2 postoperative result was obtained after selective mesiotemporal resection. A history of febrile convulsion, particularly in the form of status epilepticus, seems to be a prognostic factor. As for presurgical evaluation, electroencephalography (EEG), magnetic resonance imaging (MRI), magnetoencephalography (MEG), and ictal single-photon emission-computed tomography (SPECT) are important tests. Recording of spontaneous seizures by means of intracranial electrodes is the most reliable for diagnosis. Ammon's horn sclerosis and mesial temporal sclerosis are the most frequent pathologic findings. The seizure mechanism was studied by means of depth EEG recordings and ictal SPECT. The hippocampal formation is more responsible than the amygdala for the origin of seizures. Preferential pathways for seizure spread may be the fornix and stria terminalis, amygdalofugal fibers, and uncinate fasciculus. The concept of mesial temporal lobe epilepsy is valid for selecting medically refractory but surgically remediable patients for surgical treatment.

[Cardiomyoplasty effectiveness: review of the mechanism]

The effectiveness of cardiomyoplasty on cardiac function is discussed, and the four mechanisms proposed to explain cardiomyoplasty effectiveness are reviewed. The first such mechanism, termed the squeezing effect, suggests that skeletal muscle wrapped around the heart squeezes the heart in the same way as cardiac massage, resulting in direct improvement in cardiac function. Hemodynamic improvement is rarely detectable, but significant subjective improvement is commonly seen clinically. The second mechanism, termed the sparing effect, suggests that even if cardiac performance remains unchanged after cardiomyoplasty, contraction of the wrapped lattisimus dorsi muscle causes an increase in the slope of the end-systolic pressure-volume relationship, and a reduction in left ventricular wall stress. Myocardial oxygen consumption is thereby reduced. The third mechanism, called the girdling effect, suggests that cardiomyoplasty may act like an elastic girdle around the heart to prevent enlargement of the failing heart. The fourth mechanism, called the collateral effect, suggests that, when applied to the ischemic heart, cardiomyoplasty increases collateral blood flow to the myocardium, thereby benefiting cardiac function. However, the existence of unknown mechanisms is suggested by two phenomena that cannot be explained by these four mechanisms alone. Cardiomyoplasty was introduced as a method of direct cardiac assistance. However, it now appears that the relatively passive role of cardiomyoplasty in oxygen consumption saving and ventricular enlargement prevention may be of great importance.

Synthesis of sulfated octadecyl ribo-oligosaccharides with potent anti-AIDS virus activity by ring-opening polymerization of a 1,4-anhydroribose derivative

The synthesis and anti-AIDS virus activity of sulfated octadecyl ribofuranans with medium-range molecular weights have been investigated. Selective ring-opening polymerization of 1,4-anhydro-2,3-di-O-benzyl-alpha-D-ribopyranose with 10-20 mol% of boron triflouride etherate as a catalyst in a large amount of dichloromethane gave 2,3-di-O-benzyl-(1-->5)-alpha-D-ribofuranan in good yield. The molecular weight of the benzylated ribofuranan was in the range of 9 x 10(3) to 10 x 10(3). Debenzylation of the polymer followed by acetylation gave peracetylated (1-->5)-alpha-D-ribofuranans. The peracetylated ribofuranans were treated with octadecyl alcohol and a stannic chloride catalyst to afford acetylated ribofuranans having octadecyl groups at the reducing terminal. The molecular weights of the resulting acetylated octadecyl ribofuranans were below 9 x 10(3). Sulfation of the deacetylated octadecyl ribofuranans by piperidine-N-sulfonic acid in dry Me2SO gave sulfated octadecyl ribofuranans with molecular weights of 3 x 10(3) to 9 x 10(3) and sulfur contents of 13.0-16.2%. The sulfated octadecyl ribofuranans had potent anti-AIDS virus activity, EC50 = 0.6-2.5 micrograms/mL (a standard curdlan sulfate showed EC50 = 0.43 micrograms/mL), and low anticoagulant activity, 4-17 units/mg (a standard dextran sulfate, 22.7 unit/mg). Structural analysis of the ribofuranans was performed by NMR at 400 and 600 MHz.