MTG8 proto-oncoprotein interacts with the regulatory subunit of type II cyclic AMP-dependent protein kinase in lymphocytes

AML1-MTG8 chimeric oncogene is generated in acute myelogenous leukemia with t(8;21), and seems to be responsible for the pathogenesis of the disease. However, the role of MTG8 is ambiguous. Here we found that MTG8 interacted with the regulatory subunit of type II cyclic AMP-dependent protein kinase (PKA RIIalpha). The binding site of MTG8 was NHR3 domain, and that of RIIalpha was the N-terminus for interacting with PKA anchoring proteins (AKAPs). NHR3 contains a putative alpha-amphipathic helix which is characteristic in binding of AKAPs with RII. Indirect immunofluorescence microscopy showed that MTG8 and RIIalpha were overlapped at the centrosome-Golgi area in lymphocytes. These findings suggest that MTG8 may function as an AKAP at the centrosome-Golgi area in lymphocytes.

Syndrome of microcephaly, Dandy-Walker malformation, and Wilms tumor caused by mosaic variegated aneuploidy with premature centromere division (PCD): report of a new case and review of the literature

We report a male infant with multiple congenital anomalies and mosaic variegated aneuploidy; a rare cytogenetic abnormality characterized by mosaicism for several different aneuploidies involving many different chromosomes. He had prenatal-onset growth retardation, microcephaly, dysmorphic face, seizures, hypotonia, feeding difficulty, and developmental delay. In addition, he developed bilateral Wilms tumors. Neuroradiological examination revealed Dandy-Walker malformation and hypoplasia of the cerebral hemisphere and pons. Cytogenetic analysis revealed various multiple numerical aneuploidies in blood lymphocytes, fibroblasts, and bone marrow cells, together with premature centromere division (PCD). Peripheral blood chromosome analysis from his parents also showed PCD, but no aneuploid cells. The clinical phenotype and multiple aneuploidies of the patient may be a consequence of the homozygous PCD trait inherited from his parents. Comparison with previously reported cases of multiple aneuploidy suggests that mosaic variegated aneuploidy with PCD may be a clinically recognizable syndrome with major phenotypes being mental retardation, microcephaly, structural brain anomalies (including Dandy-Walker malformation), and possible cancer predisposition.

Correlation of telomerase activity with development and progression of adult T-cell leukemia

Telomerase is an enzyme that adds hexameric TTAGGG nucleotide repeats to the ends of vertebrate chromosomal DNAs (i.e. telomeres) to compensate for losses that occur with each round of DNA replication. Telomerase activity, demonstrable in most human tumors, enables them to maintain telomere stability. Peripheral blood mononuclear cells were sampled from 57 patients seropositive for human T-lymphotropic virus type I (HTLV-I), including 24 asymptomatic viral carriers, ten smoldering type, five chronic type, and 18 acute type adult T-cell leukemia (ATL). Telomerase activity was determined in samples using a modified telomeric repeat amplification protocol. We semiquantitatively determined telomerase activity by serial dilution of each sample. All of 23 samples from acute and chronic type ATL patients were positive, seven of ten (70%) smoldering type patients and seven of 24 (29.2%) asymptomatic viral carriers were positive. Disease progression from asymptomatic viral carrier to acute type correlated with telomerase activity. Two samples from chronic type ATL patients with relatively high telomerase activity progressed to the acute type within 1 month. Serum lactate dehydrogenase level also correlated with telomerase activity. These results indicate that reactivation of telomerase activity is a key event in development and progression of ATL, and telomerase could be a useful marker for predicting the course of disease. Accordingly, ATL could be a good candidate disease for trials of telomerase inhibitors, as novel anticancer drugs.

Local VEGF administration enhances healing of colonic anastomoses in a rabbit model

BACKGROUND/AIMS

Many studies report the role of vascular endothelial growth factor (VEGF) in wound healing, but few describe local VEGF administration to the digestive tract. Leakage from colonic anastomoses, including those due to ischemia, represents a major complication causing increased mortality and morbidity. Angiogenesis is crucial to anastomotic healing and restoration of blood supply, and VEGF is a potent angiogenic factor showing improved healing in various models of reconstruction and anastomosis. Here, we examine the effects of local VEGF-A(165) administration on postoperative rabbit colon anastomosis.

METHODS

Two colotomies per animal were made in the sinistral colon on opposite sides of the mesentery. Randomly assigned VEGF (10 microg/0.1 ml) or saline (0.1 ml) was injected into the muscularis propria on both sides of each colonic anastomosis before closing the access laparotomy using single-layer sutures. On postoperative days 3, 4 and 7, the bursting pressure of partially healed anastomoses was measured. On postoperative day 4, anastomotic tissues were examined for the following: hydroxyproline; histopathologically for inflammatory infiltrate and tissue organization and immunohistochemically for capillary proliferation and density; vessel density of midzone collaterals around anastomoses by microangiography.

RESULTS

Compared to saline, VEGF administration significantly improved bursting pressure (p = 0.014, paired t test) and increased hydroxyproline (p = 0.027, paired t test) on postoperative day 4. Inflammatory cell infiltration and fibroblast proliferation were prominent, and submucosal capillary vascular counts were significantly higher for VEGF.

CONCLUSIONS

Administration of VEGF to colonic anastomosis accelerates wound healing and strengthens the anastomosis by increased angiogenesis.

Two unrelated cases of single maxillary central incisor with 7q terminal deletion

Two unrelated cases of single maxillary central incisor (SM-CI) with 7q terminal deletion of the same breakpoint at 7q36.1 were described. They had mental retardation, microcephaly, hypotelorism, short stature, and normal levels of plasma growth hormone. One case had bilateral caudal ectopic kidneys, double renal pelves, and dilated ureters. The other had bilateral hydroureteronephrosis. The present cases suggest that 7q terminal deletion is one of the causes of SMCI.

Ruvalcaba syndrome: autosomal dominant inheritance

A kinship is described in which nine individuals in four generations were affected with the Ruvalcaba syndrome including postnatal growth retardation, an oval face with a high forehead, antimongoloid slant of palpebral fissures, small beaked nose with hypoplastic nasal alae, small downturned mouth with thin vermilion borders, pointed chin, and short fingers and toes. Less frequently seen were osteochondritis of the lumbar vertebral bodies, cone-shaped epiphyses of the phalanges, and narrow diaphyses of the metacarpals and metatarsals. None of the affected individuals was mentally retarded. The propositus, a 3-year-old boy, and his mother were typically affected, while his 8-month-old sister, the 55-year-old maternal grandfather, and his 46-year-old younger sister had several of these manifestations. Information on the remaining four affected relatives was incomplete. The syndrome was transmitted in a dominant fashion with variable expressivity. There were two instances of male-to-male transmission. This effectively ruled out X-linked inheritance. The transmission of the syndrome in three other reported pedigrees was also compatible with autosomal dominant inheritance with variable expressivity and incomplete penetrance.

Two Japanese cases with microcephalic primordial dwarfism: classical Seckel syndrome and osteodysplastic primordial dwarfism type II

A male infant with "classical" Seckel syndrome and a girl with osteodysplastic primordial dwarfism type II are described. The boy with classical Seckel syndrome had severe brain dysplasia, a finding hitherto unreported in patients with this syndrome. The patient with osteodysplastic dwarfism type II had skeletal abnormalities including lumbar scoliosis, a small and high pelvis, metaphyseal flaring of the distal radii and ulnae, V-shaped metaphyseal flaring of the distal femorae, and short metacarpals and phalanges. The mother of this girl was short, microcephalic, and had disproportionately short forearms and legs. In view of this, dominant inheritance of the disease was suggested.

Amelioration of microvascular myocardial ischemia by gene transfer of vascular endothelial growth factor in rabbits

OBJECTIVES

Restoration of coronary blood flow by angiogenesis may offer a new approach to intractable ischemic heart disease. In the present study, we investigated the angiogenic effects of gene transfer of vascular endothelial growth factor 165 on microvascular myocardial ischemia.

METHODS

A rabbit model of microvascular myocardial ischemia was created by plugging coronary microvessels with microspheres (15 microm in diameter, 2.8 x 10(5)/kg, n = 29). Gene transfer was performed by semi-selective intracoronary injection of recombinant adenovirus expressing vascular endothelial growth factor 165 forty minutes after microsphere injection (n = 9).

RESULTS

Microsphere injection reduced myocardial perfusion (78% +/- 9% of baseline tissue flow) and diminished myocardial contraction (61% +/- 12% of the baseline ejection fraction) and cardiac performance (elevated left ventricular end-diastolic pressure and decreased systemic flow) in the acute phase. At 17 +/- 3 days, gene transfer of vascular endothelial growth factor 165 had had the following effects: (1) promoted coronary angiogenesis as evidenced by myocardial flow above the baseline (121% +/- 24%), (2) increased vascular density revealed by synchrotron radiation microangiography and histologic analysis, (3) ameliorated the degree of myocardial ischemia as evidenced by myocardial lactate content and the extent of histologic necrosis, and (4) restored heart function as evidenced by increased ejection fraction (95% +/- 10%), reduced left ventricular end-diastolic pressure, and restored body weight.

CONCLUSIONS

In vivo vascular endothelial growth factor 165 gene transfer promoted angiogenesis and was an effective approach to treating microvascular myocardial ischemia.

Differential gene expression of human telomerase-associated protein hTERT and TEP1 in human hematopoietic cells

The maintenance of telomere length is crucial for the survival of cells. Recently, genes for proteins that consist of human telomerase have been cloned and the results have indicated a close relationship between telomerase activity and its gene expression. We studied the mRNA expression of the telomerase-associated genes, hTERT and TEP1, in hematopoietic cells in order to clarify the relation between them and telomerase activity using semiquantitative RT-PCR. In polymorphonuclear cells and monocytes isolated from peripheral blood, which had no detectable telomerase activity, no hTERT mRNA expression was seen. On the other hand, lymphocytes and CD34-positive cells both demonstrated hTERT mRNA expression. TEP1 mRNA was detected in all samples, showing no differential expression. We then assessed hTERT and TEP1 mRNA expression in CD34-positive cells cultured in vitro with growth factors. After 4 weeks of culture, all the cells showed myeloid differentiation and the telomerase activity was downregulated. hTERT mRNA was expressed in CD34-positive cells, but was downregulated in 4-week-cultured cells. TEP1 showed no apparent differential expression. We conclude that hTERT mRNA expression is downregulated in accordance with telomerase downregulation during the course of myeloid differentiation, which suggests that it plays a crucial role in the expression of enzyme activity, while TEP1 has a much smaller role to play, if any.

A case of rhabdomyosarcoma of the bladder with a (2;5) chromosomal translocation in peripheral lymphocytes

Chromosome analysis was performed on peripheral blood lymphocytes of a patient with rhabdomyosarcoma of the urinary bladder. It showed a reciprocal t(2;5) translocation with the breakpoints at 2q37.3 and 5q31.3. This is the first report of such an anomaly in the peripheral lymphocytes of a patient with rhabdomyosarcoma of the urinary bladder.

Successful treatment of echovirus meningoencephalitis in sex-linked agammaglobulinaemia by intrathecal and intravenous injection of high titre gammaglobulin

A 7-year-old boy with sex-linked agammaglobulinaemia developed meningoencephalitis caused by echovirus type 11. He had convulsions, right hemiplegia, cortical motor aphasia, left abducens nerve paralysis, left hypoglossal nerve paralysis, and later became unconscious. Treatment by intravenous injection of conventional gammaglobulin and intrathecal alpha-interferon brought no clinical improvement, but intrathecal administration together with intravenous injection of gammaglobulin containing a high titre of anti-echovirus type 11 antibody was associated with a dramatic improvement in his clinical symptoms. After subsequent periodical (once or twice a week) administration of specific gammaglobulin for 8 months, the echovirus in his cerebrospinal fluid was no longer detected. These findings suggest that intrathecal injection combined with intravenous injection of high titre anti-echovirus type 11 antibody was effective in treating this case of echovirus meningoencephalitis in sex-linked agammaglobulinaemia.

Giant hepatic granuloma caused by Bartonella henselae

We report a 10-year-old girl with a 3.0- by 3.5-cm giant hepatic granuloma caused by Bartonella henselae. Such a solitary and large granuloma associated with B. henselae infection has not been previously reported. We believe that B. henselae infection is a consideration in the differential diagnosis of a large hepatic mass.

Ticlopidine-Associated thrombotic thrombocytopenic purpura with an IgG-type inhibitor to von Willebrand factor-cleaving protease activity

A 41-year-old Japanese man complained of a left-sided visual disturbance. Imaging by magnetic resonance angiography revealed a narrowing of the left internal cervical artery. Thus, ticlopidine (Tc) administration was started at a daily dose of 300 mg. However, 2 weeks later, severe thrombocytopenia, fever, nausea, and psychiatric symptoms developed; Tc was therefore discontinued. Based on the diagnostic hallmark of 5 clinical signs, the patient's disease was diagnosed as thrombotic thrombocytopenic purpura (TTP). Daily plasmapheresis was performed for the first 4 days, and the patient's clinical signs gradually improved. Von Willebrand factor-cleaving protease (vWF-CPase) activity in his plasma was less than 3% of that of the control sample at diagnosis, but that value recovered steadily following plasmapheresis. In addition, immunoglobulin G purified from the patient plasma inhibited vWF-CPase activity in normal plasma with a specific activity of 0.8 Bethesda units/mg. No sign of TTP relapse has been noted following cessation of Tc. Thus, it was concluded that the patient developed TTP by producing an inhibitory autoantibody against vWF-CPase activity that was presumably triggered by Tc administration.

Translocation t(X;21)(q13.3; p11.1) in a girl with Menkes disease

A girl with a 46,X,t(X;21) (q13.3;p11.1) karyotype presented with skin redundancy, especially in the neck, prominent occiput and micrognathia, and later developed hypotonia, hypopigmentation, sparse scalp hair, and profound mental retardation characteristic of Menkes disease. Her serum copper (14 microg/dl) and ceruloplasmin (9 mg/dl) levels were extremely low. Fluorescent in situ hybridization analysis with a 100-kb P1-derived artificial chromosome probe containing the Menkes disease gene demonstrated three twin-signals, one on the normal X chromosome and one each on derivative chromosomes X and 21, indicating that the Xq13.3 breakpoint was located within the gene. Replication pattern analysis showed that the normal X chromosome was late replicating, whereas the derivative X chromosome was selectively early replicating. These results indicated that Menkes disease in our patient resulted from a de novo translocation that disrupts the disease gene.

Establishment of a human glioma cell line bearing a homogeneously staining chromosomal region and releasing alpha- and beta-type transforming growth factors

A human glioma cell line (YKG1), which was positively identified for glial fibrillary acidic (GFA) and S-100 proteins, was established from a surgical specimen of a patient with glioblastoma. Chromosome analysis of the cells revealed a homogeneously staining region (HSR) on a marker chromosome. The assay for transforming growth factors (TGFs) in the conditioned medium of the cell line revealed that it contained high levels of alpha- and beta-type TGFs, which might regulate the growth of glioblastoma and influence on the peritumoral tissues.

Occlusion of the semicircular canal using argon laser

The effects of argon laser on the bony semicircular canals were studied in the guinea pig. After intraperitoneal administration of Nembutal, the bulla was opened in order to approach the lateral and posterior canals. The anterior canal was approached through the posterior fossa. The argon laser was applied through a probe which was connected to a device from HGM Medical Laser Systems. One of the three semicircular canals was irradiated one to several times by argon laser (1.0-1.5 W x 0.5 sec). Histopathologic examination of the temporal bones revealed that the semicircular duct shrank immediately after irradiation. The laser produced a charred area in the bony canal wall. The semicircular canals gradually became fibrotic and ossified and completely occluded within several weeks. Heat produced in the bony canal may be responsible for the morphologic changes. On delayed observation, the cochlea of the canal-irradiated animals showed no morphologic changes. Auditory brain stem responses were normal. Caloric stimulation using 5 ml/5 sec of ice water revealed no response in the lateral canal-irradiated animals.

[The development of language and problems in 30 mild, moderate, and moderately severe hearing-impaired children]

Some mild, moderate, and moderately severe-hearing impaired children have poor language and educational problems despite comparatively good hearing. We studied 30 mild, moderate, and moderately severe hearing-impaired children cared for at Showa University and Jiseikai Hospitals. Their ages ranged from 3 to 14 years and average hearing from 35.0 dB HL to 68.8 dB HL. Our findings were as follows: (1) The average age of suspected hearing problem onset was 2 years 10 months. On the average, delayed diagnosis was made at 4 years 2 months and children were fitted with hearing aids at 5 years 3 months. (2) Over 25% them wore hearing aids infrequently. (3) Language delay was observed in 14 of 24 children examined using the WISC-III test. Many wore hearing aids infrequently and exhibited inadequate oral communication in Japanese due, for example, to deaf parents or children educated overseas. (4) According to a questionnaire, many mothers usually talked to the children aware of their hearing condition. But almost mothers of children with delayed development could not teach children if they couldn't hear, and only repeated same words for children's clarification, e.g., "Pardon?". It is important to detect hearing impairment in children as early as possible. Guidance by specialists and communication training are very important, especially for children who are mild, moderate, and moderately severe hearing-impaired.

Pattern modification of a neuronal network for individual-cell-based electrophysiological measurement using photothermal etching of an agarose architecture with a multielectrode array

A new type of individual-cell-based on-chip multielectrode array (MEA) cell-cultivation system with an agarose microchamber (AMC) array for topographical control of the network patterns of a living neuronal network has been developed. The advantages of this system are that it allows control of the cell positions and numbers for cultivation using AMCs, as well as easy and flexible control of the pattern of connections between the AMCs through photothermal etching where a portion of the agarose layer is melted with a 1480 nm infrared laser beam. With adequate laser power, narrow micrometer-order grooves (microchannels) can easily be fabricated that can be used to combine neighbouring AMCs to enable topographical control of the neural network pattern. Using this system, an individual-cell-based neural network pattern was formed of rat hippocampal cells within the AMC array without cells escaping from the electrode positions in the microchamber during an eight-day cultivation, and could record cell firing in response to 1.5 V, 500 kHz stimulation through an electrode. This demonstrated the potential of the on-chip AMCMEA cell cultivation system for long-term single-cell-based electrophysiological measurement of a neural network system.

Family study of common fragile sites

The frequency of folate-sensitive common fragile sites (1p31, 1q44, 3p14, 3q26.2, 6q26, 16q23, Xp22.3) was determined in 19 healthy individuals from four families. The individuals consisted of 12 males and 7 females from 1 to 59 years of age. The frequency showed intrafamilial variation, but we were unable to demonstrate that the frequency was inherited in a Mendelian codominant fashion. In eight subjects whose chromosome 3 homologues could be distinguished by Q-band polymorphism, breakages at 3p14 occurred with equal frequencies on the homologues. Our study suggests that common fragile sites are a part of normal chromosome structure, and the frequency of their expression largely depends on environmental factors.

Induction of MTG8-specific cytotoxic T-cell lines: MTG8 is probably a tumour antigen that is recognized by cytotoxic T cells in AML1-MTG8-fused gene-positive acute myelogenous leukaemia

Several reports have demonstrated the persistent detection of AML1-MTG8 fusion products, representing minimal residual disease (MRD), in patients with t(8;21) acute myelogenous leukaemia (AML) who are in long-term remission. It is probable that immune-mediated mechanisms that are able to suppress the expansion of MRD may result in the continuance of remission. It was previously shown that some t(8;21) AML patients had high anti-MTG8 antibody titres. MTG8 expression in normal adult tissues is limited to the brain or heart in which human leucocyte antigen (HLA) class I cell-surface antigens are either not or are only faintly detectable. We hypothesized that the overexpression of the MTG8 gene in t(8;21) AML cells could act as a possible tumour antigen, which might be able to induce the immune-mediated suppression of the expansion of MRD. We were able to induce HLA-A0201-restricted cytotoxic T-lymphocyte (CTL) lines against an MTG8 peptide (MTG8b amino acids 182-191) using monocyte-derived dendritic cells from a healthy donor. T-cell receptor (TCR)Valpha17, TCRVbeta14 and 15, and TCRJbeta2.1 and 2.3 are predominantly used in these CTL lines. Our data, which suggest that the MTG8 protein could be one of the tumour antigens recognized by CTLs, may be helpful in further investigations of TCR analysis in t(8;21) AML patients with HLA-A0201 who are in long-term remission.

Pachygyria, joint contractures, and facial abnormalities: a new lethal syndrome

Images

Transmyocardial revascularization aggravates myocardial ischemia around the channels in the immediate phase

We examined whether transmyocardial revascularization (TMR) relieves myocardial ischemia by increasing regional perfusion via the transmural channels in acute canine experiments. Regional blood flow during transient coronary ligation (2 min) was compared before and 30 min after TMR, and at the third transient ischemia the mid-left ventricle (LV) was cut and immediately frozen along the short axis for the analysis of NADH fluorescence in the regions around the TMR channels. In low-resolution analysis (2-4 g tissue or 2-3 cm(2) area), regional perfusion was not significantly altered after TMR, and NADH fluorescence was observed throughout the ischemic region without significant spatial variation. High-resolution analysis (2.8 mg, 1 mm x 1 mm) revealed that the flow after TMR was lower, and NADH fluorescence was higher in the regions close to the channels (1-2 mm) than in the regions 3-4 mm away from them. Creating TMR channels did not improve the regional perfusion and rather aggravated the local ischemia in the vicinity of the channels in the immediate phase.