Rat RT6.2 and mouse Rt6 locus 1 are NAD+: arginine ADP ribosyltransferases with auto-ADP ribosylation activity

RT6 is a glycosylphosphatidylinositol-linked protein found on the surface of mature rat T lymphocytes. Cells that express RT6 have an immunoregulatory function and modulate the expression of autoimmune diabetes mellitus in the BioBreeding rat. A homologue of the rat RT6 gene, designated Rt6, has been identified in the mouse, but expression of mouse Rt6 protein has not been documented. Rat RT6 is known to be a nicotinamide adenine dinucleotide (NAD+) glycohydrolase. We now report that rat RT6.2 and recombinant mouse Rt6 locus 1 proteins possess auto-ADP ribosylation activity. In addition, mouse Rt6 but not rat RT6, catalyzes the ADP ribosylation of exogenous acceptors such as histones. The ADP-ribosyl-protein bonds in auto-ADP-ribosylated rat RT6.2, auto-ADP-ribosylated mouse Rt6, and ADP-ribosylhistone synthesized by Rt6 were stable to HgCl2 and HCl, but labile to NH2OH, consistent with ADP ribosylarginine linkages. To determine if these enzymatic activities could affect the function of rat T cells, the effect of substrate availability on lymphocyte proliferation was examined. An inverse correlation was observed between NAD+ concentration in the medium and the ability of rat T cells to respond to anti-CD3, ConA, and PMA plus ionomycin. The data suggest that lymphocyte surface ADP ribosyltransferases could be involved in signaling and immunoregulatory processes.

Rat RT6.2 and mouse Rt6 locus 1 are NAD+: arginine ADP ribosyltransferases with auto-ADP ribosylation activity

RT6 is a glycosylphosphatidylinositol-linked protein found on the surface of mature rat T lymphocytes. Cells that express RT6 have an immunoregulatory function and modulate the expression of autoimmune diabetes mellitus in the BioBreeding rat. A homologue of the rat RT6 gene, designated Rt6, has been identified in the mouse, but expression of mouse Rt6 protein has not been documented. Rat RT6 is known to be a nicotinamide adenine dinucleotide (NAD+) glycohydrolase. We now report that rat RT6.2 and recombinant mouse Rt6 locus 1 proteins possess auto-ADP ribosylation activity. In addition, mouse Rt6 but not rat RT6, catalyzes the ADP ribosylation of exogenous acceptors such as histones. The ADP-ribosyl-protein bonds in auto-ADP-ribosylated rat RT6.2, auto-ADP-ribosylated mouse Rt6, and ADP-ribosylhistone synthesized by Rt6 were stable to HgCl2 and HCl, but labile to NH2OH, consistent with ADP ribosylarginine linkages. To determine if these enzymatic activities could affect the function of rat T cells, the effect of substrate availability on lymphocyte proliferation was examined. An inverse correlation was observed between NAD+ concentration in the medium and the ability of rat T cells to respond to anti-CD3, ConA, and PMA plus ionomycin. The data suggest that lymphocyte surface ADP ribosyltransferases could be involved in signaling and immunoregulatory processes.

Estrogen-related receptor, hERR1, modulates estrogen receptor-mediated response of human lactoferrin gene promoter

We have shown previously that estrogen-stimulated transcription from the human lactoferrin gene in RL95-2 endometrium carcinoma cells is mediated through an imperfect estrogen response element (ERE) at the 5 -flanking region of the gene. Upstream from the ERE, a DNA sequence (-418 to -378, FP1) was selectively protected from DNase I digestion by nuclear extracts from endometrial and mammary gland cell lines. In this report, using the electrophoresis mobility shift assay, site-directed mutagenesis, and DNA methylation interference analyses, we show that three different nuclear proteins bind to the FP1 region (C1, C2, and C3 sites). The nuclear receptor, COUP-TF, binds to the C2 site. Mutations in the C1 binding region abolish C1 complex formation and reduce estrogen-dependent transcription from the lactoferrin ERE. When the imperfect ERE of the lactoferrin gene is converted to a perfect palindromic structure, the enhancing effect of the C1 binding element for estrogen responsiveness was abolished. We isolated a complementary DNA (cDNA) clone from an RL95-2 expression library that encodes the C1 site-binding protein. The encoded polypeptide maintains 99% amino acid identity with the previously described orphan nuclear receptor hERR1. A 2.2-kilobase mRNA was detected in RL95-2 cells by the newly isolated cDNA but not by the first 180 base pair of the published hERR1 sequence. By Western analysis, a major 42-kDa protein is detected in the RL95-2 nuclear extract with antibody generated against GST-hERR1 fusion protein. Finally, we show that the hERR1 interacts with the human estrogen receptor through protein-protein contacts.

Epidermal growth factor stimulates the cell growth of the PA-1 teratocarcinoma cell line in an autocrine/paracrine fashion

In order to investigate the biological significance of epidermal growth factor (EGF) in the cell function of teratocarcinoma cells, we examined the production, binding and cell proliferative effect of EGF in PA-1 human ovarian teratocarcinoma cell line. The immunoreactivity of EGF in PA-1 cell-conditioned medium was detected by human EGF radioimmunoassay, and prepro-EGF mRNA was demonstrated in PA-1 cells by Northern blot analysis. An [125I]EGF binding study showed the presence of EGF receptor with very high binding affinity and relatively low numbers of binding sites in PA-1 cells. Furthermore, the growth of PA-1 cells was stimulated by EGF and inhibited by anti-EGF monoclonal antibody. These results suggest strongly that EGF plays an important role in controlling the growth of teratocarcinoma cells as an autocrine/paracrine growth factor.

[Cerebral digital tomosynthetic angiography for planning stereotactic biopsy of brain tumor]

We used cerebral digital tomosynthetic angiography for planning the probe trajectory of stereotactic biopsy of brain tumors in four patients. The probe trajectory was basically planned by MRI examinations. However, cerebral digital tomosynthetic angiography demonstrated detailed three-dimensional vascular anatomy around the brain tumors, and therefore was very helpful in revising the planned trajectory when there was a fairly large vessel likely to cross with it.

Digital angiotomosynthesis for preoperative evaluation of cerebral arteriovenous malformations and giant aneurysms

PURPOSE

To evaluate the clinical utility of the digital angiotomosynthesis technique for giving additional information regarding critical anatomy of cerebrovascular lesions before surgical intervention.

METHOD

Seven arteriovenous malformations and three giant aneurysms were examined with digital angiotomosynthesis; these images were compared with conventional angiograms.

RESULTS

1) Detailed recognition of three-dimensional vascular structures of the arteriovenous malformation and giant aneurysm was facilitated by the cine mode of digital angiograms and angiotomograms. 2) Reconstructed angiotomograms could show clear separation of overlapping vessels and demonstrate fine vasculature. 3) Fine feeders, which were difficult to trace on the conventional angiogram, were more easily recognized in all cases of arteriovenous malformation. 4) Small arteries passing in close proximity to the arteriovenous malformation nidus were identifiable. 5) Fine arterial branches, being obscured by big shadows of giant aneurysms on the conventional angiograms, were well identified. 6) The anatomic relationship of bone structures to the giant aneurysm was clearly shown.

CONCLUSIONS

Digital angiotomosynthesis is helpful for recognizing the three-dimensional and detailed vascular anatomy of arteriovenous malformations and giant aneurysms and provides neurosurgeons with useful information for preoperative evaluation.

[Hematological analysis of leukemic diseases using an automated hematology analyzer]

Owing to recent technical developments in automated hematology analyzers, identification of 5-part differential counts in white blood cells and also of abnormal leukocytes has become possible. Blood specimens from 200 patients with leukemic hematologic conditions were processed through a Coulter STKS which gives a favorable white cell differential count utilizing the following parameters: volumetric impedance (V), electric conductivity/cell volume (C), and a monochromatic laser beam which provides collectively white cell scatterplot (S). To analyze the presented figures of a pathologic scatterplot (SP) on the visual display unit, the standard scale derived from 220 normal SP patterns which was composed of four kinds of cell SP scales (neutrophil: N, monocyte: Mo, eosinophil: Eo, lymphocyte: Ly) was applied. Leukemic SP figures were variable depending upon both the type of FAB classification and their therapeutic processes. SP forms of M0-blasts were semi-round and located in the central area surrounded by N-, Mo-, and Ly-SP scale. Blast SP of M1 and M2 was shown as a developing process to the SP field containing immature myeloid cells extending from the central area. It was reasonable that immature neutrophilic SP expression was obtained in M3 and Ph1 positive CML. However, the SP of M3v and Ph1 negative CML showed myelomonocytic features as CMMoL does. Typical myelomonocytic SP patterns were obtained in M4 patients. SP figures of MDS were characterized by deformability, dislocation and another abnormality, and these changes, especially in lymphocytes are very useful for diagnosis of MDS. Therefore, the FAB subtype of AML including MDS and CML could be distinguished from each other on the basis of SP pattern. In lymphoproliferative disorders, limited conductivity in ALL-SP was characteristic, while irregular and deformed SP was peculiar in leukemic malignant lymphoma. It would be a valuable process to analyze the SP pattern obtained from an automated hematology analyzer for identification of leukemic diseases.

Ontogenesis and distribution of epidermal growth factor immunoreactivity and binding activity in the mouse fetal and neonatal tissues

Epidermal growth factor (EGF) immunoreactivity, EGF binding activity, and their ontogenic changes were investigated in placenta, amnion, and various organs of mouse fetus and neonate. EGF immunoreactivity was detected in all organs examined such as fetal and neonatal liver, brain, lung, intestine, placenta, and amnion. The fetal tissues having relatively higher EGF content were amnion, liver, and intestine. The tissue distribution of EGF immunoreactivity in the fetus did not differ from that in neonate. As for its ontogenesis, EGF immunoreactivity was almost constant during fetal development in liver, brain, and placenta, whereas it gradually increased in intestine. Scatchard plot analysis of EGF receptor, which was also demonstrated in all organs studied, revealed that EGF receptor in these tissues showed curvi-linear profile and its affinity was very high. Unlike EGF immunoreactivity, EGF binding activity showed tissue distributional difference between fetus and neonate except skin; EGF binding activity was relatively high in heart, kidney, lung, and intestine in the fetus, whereas it was high in liver, kidney, heart, and lung in the neonate. As for its ontogenesis, EGF receptor increased in liver as gestation proceeded, while it decreased in intestine. These results suggest that the biological importance of EGF in fetal development may be variable among fetal organs despite the ubiquitous existence of EGF and its receptor in many fetal tissues.

[Pathophysiology and diagnosis of malignant neoplastic disorders of the hematopoietic system]

The Pathophysiological analysis of hematopoietic tumors has advanced markedly owing to the progress in the fields of histomorphology, biochemistry, hematopoietic stem cells including cytokines, cell surface markers, cytogenetics, and molecular biology. This progress has led to the establishment of many new disease concepts and has almost completely changed the recognition of hematopoietic tumors. These basic studies have also supported the development of effective therapy of hematopoietic tumors. Of course, this progress has been reflected in the techniques and knowledge in routine laboratory evaluation.

Immobilized DPP and other proteins modify OCP formation

Osteonectin, gamma-carboxyglutamic acid-containing (Gla) protein, and dentin phosphoprotein were covalently attached to sepharose beads and inoculated in solutions at two different degrees of supersaturation with respect to both octacalcium phosphate (OCP) and hydroxyapatite. In both solutions, the inhibitory activity towards de novo formation of calcium phosphate that these proteins display when freely dissolved in solution was completely eliminated when they were immobilized on the sepharose at concentrations of up to 5 micrograms/mg wet beads. In the solution that was more highly supersaturated with respect to OCP, the immobilized dentin phosphoprotein, moreover, was found to induce de novo formation of OCP in proportion to the concentration of the protein immobilized. For example, at 10 micrograms/ml of the immobilized dentin phosphoprotein, the induction period was reduced more than 50%. However, in the solution considerably less supersaturated with respect to OCP, none of the immobilized proteins were capable of inducing OCP or apatite deposition. These findings suggest that the immobilized dentin phosphoprotein could work as a nucleating substrate for the OCP phase in solutions where calcium and phosphate concentrations are sufficiently higher than equilibrium saturation levels for the OCP phase.

Dorsal internal carotid artery aneurysms with special reference to angiographic presentation and surgical management

Aneurysms arising from the dorsal wall of the internal carotid artery are rare. The authors surgically treated twenty dorsal internal carotid artery aneurysms. Pre-operative angiographic findings were reviewed and classified into three types. Eleven aneurysms projecting superiorly on the lateral angiogram were found to be adherent to the base of the frontal lobe by the pterional approach. Five aneurysms which had been superimposed with the internal carotid artery on the lateral angiogram were found adhered to the medial surface of the temporal lobe. Four aneurysms not seen on the angiogram had no adhesion. Two aneurysms, which had not been seen on the initial angiograms, were visualized on the angiograms taken during the period of vasospasm. This type of aneurysms can be the source of a subarachnoid haemorrhage of unknown origin and requires repeated examinations. Premature rupture occurred intra-operatively in five cases and postoperative bleeding was encountered in two. Clipping technique is discussed from the viewpoint of preventing intra- and postoperative rupture.

Development of a high-resolution digital tomosynthesis system and its clinical application

Conventional tomography has been criticized for its low contrast caused by scattered radiation and tomographic blur. The authors developed a digital tomosynthesis system as a substitute for conventional tomography. With the image processor in the system, two types of postprocessing can be performed to improve the quality of synthesized tomograms. One-dimensional spatial frequency filtering effectively reduces linear tomographic blur and enhances image information when an appropriate filter is used. Correction of structure mottle helps enhance the image clarity. The system allows reconstruction of tomograms at any desired depth and performance of tomosynthetic angiography and dual-energy subtraction. The system solves some of the problems associated with plain tomography and dual-energy subtraction and provides diagnostic clinical images.

Effect of media conditioned by concanavalin A activated spleen cells on pancreatic islet cells

The effect of media conditioned by concanavalin A-activated spleen cells (C-sup) on insulin release and its islet cell cytotoxicity were studied. In a functional study, C-sup significantly inhibited both basal insulin release and glucose-stimulated insulin release. Morphologically, C-sup had a destructive effect on isolated islets after 72 h incubation. Islet cell cytotoxicity was shown by lactate dehydrogenase (LDH) release assay after 5 days incubation with C-sup in a dose-dependent manner. These results suggest that acceleration of the onset of diabetes in young diabetes prone (DP) Bio-Breeding/Worcester (BB/W) rats following the injection of C-sup may depend on the suppressive and cytotoxic effects of C-sup on pancreatic islet cells.

Dietary treatment ameliorates overt diabetes and decreased insulin secretion to glucose, induced by overeating in impaired glucose tolerant mice

Overt diabetes (NIDDM) was induced by overeating in neonatally streptozocin (60 mg/kg.BW) treated impaired glucose tolerant mice. We imposed a food restriction and a high fiber diet to evaluate the effects of dietary treatment in this NIDDM model mouse. Furthermore, insulin secretion after the dietary treatment was studied using the perfused pancreas technique. One group of IGT mice (SZ) was maintained on ordinary mouse chow during 6 to 14 weeks of age. The others received a cookie and chocolate mashed diet (C.C. diet) to induce overt diabetes during 6 to 10 weeks of age. Thereafter, the mice with induced overt diabetes were divided according to their diet treatment. The C.C. diet was continued in one group (SZC) for 4 weeks, and the others were divided into a food restriction group (SZR: 4 g/mouse/day of ordinary mouse chow, for 4 weeks) and a high fiber diet group (SZF: 20% W/W of cellulose in ordinary mouse chow, for 8 weeks). The mean caloric intake/mouse/day in SZC, SZR and SZF were 140, 80 and 98% of that in SZ, respectively. Amelioration of hyperglycemia and impaired glucose tolerance was noted in SZR and SZF. A better glycemic control was obtained in SZF with keeping a normal growth rate. On the pancreas perfusion, the insulin secretion to 30 mM glucose was improved in SZR and SZF. Furthermore, the incremental first phase peak insulin release to 30 mM glucose in SZF was significantly greater than that in SZC (SZF, 10.5 +/- 1.0 vs. SZC, 4.5 +/- 1.9 microU/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Overt diabetes induced by overeating in neonatally STZ-treated impaired glucose tolerant mice: long-term follow up study

This study has investigated the effect of a long period of overeating on the glycemic control and pancreatic beta-cell function in neonatally streptozocin treated impaired glucose tolerant mice. Neonatally streptozocin (60 mg/kg) treated male ICR mice with 150-200 mg/dl of fed blood glucose levels were divided into two groups at 6 weeks of age. One group was maintained on a cafeteria diet (SZC) and the other on ordinary mouse chow (SZ) until 30 weeks of age. Normal male ICR mice were divided into a cafeteria diet group (CC) and an ordinary chow group (Cont). SZC and CC consumed 134-124% of the caloric intake in SZ and Cont throughout the study. Marked elevation of the fed blood glucose level was observed and the glucose tolerance was progressively impaired in SZC. On pancreas perfusion at 30 weeks of age, insulin secretion to 30 mM glucose in SZC was significantly decreased compared with that in SZ. That in CC was slightly decreased compared with that in Cont. The pancreatic insulin concentration in SZC was significantly less than that in SZ. We conclude that chronic hyperglycemia, induced by the long period of overeating, accelerated the selective loss of beta-cell sensitivity to glucose. Even in normal mice that did not have marked hyperglycemia, insulin secretion to glucose was suppressed, probably by chronic stimulation of the beta-cell due to the long period of dietary excess.

[Two-dimensional and Doppler echocardiographic findings of a sudden death case due to multiple pulmonary thromboses]

This is a case report presenting interesting findings on two-dimensional and Doppler echocardiograms due to multiple pulmonary thromboses. A 67-year-old woman had a history of surgery for colon polyps in August, 1986. After surgery, she suffered from tachycardia and dyspnea, and was admitted to our hospital because of a loss of consciousness. Sinus tachycardia, complete right bundle branch block and T-wave inversion in leads III, aVF and V1-4 were observed on her electrocardiogram. Cardiomegaly was noted on her chest radiograph. On the third hospital day, echocardiography was performed. On two-dimensional echocardiography, marked right ventricular dilatation with hypokinesis of the wall, and a flattened interventricular septum were observed on the short-axis view, and M-mode echocardiograms showed disappearance of the E wave and delay of the opening of the tricuspid valve, resulting in a monophasic triangular pattern. Doppler echocardiography showed the tricuspid valve flow to be delayed, mainly observed during atrial systole. These findings indicate decreased right ventricular compliance. The patient died on the 6th hospital day, and multiple new and old thrombi were found in the pulmonary artery at autopsy.

Somatostatin suppresses plasma aldosterone concentration in a case of Bartter's syndrome

The study was conducted to examine the effect of somatostatin on activated renin-angiotensin-aldosterone system in a case of Bartter's syndrome. After 60 minutes of 500 micrograms of somatostatin infusion, the plasma aldosterone concentration was reduced from the basal level of 250 pg/ml to 140 pg/ml, whereas plasma renin activity remained at the basal level. This result suggests that somatostatin may specifically inhibit aldosterone secretion in Bartter's syndrome and the agent can be applied to a treatment of this syndrome.

[Right and left coronary arteries-right atrial fistulas diagnosed by Doppler echocardiography: a case report]

An interesting case of right and left coronary arteries-right atrial fistulas diagnosed by Doppler echocardiography was presented. A 59-year-old woman was referred for evaluation of her continuous murmur. A thrill was palpable at the left sternal border in the third intercostal space. The proximal portions of the dilated right and left coronary arteries and distal portions of the tortuous and converging fistulas of both coronary arteries were imaged by two-dimensional echocardiography. Bidirectional continuous turbulent Doppler signals were detected in the proximal portions of the dilated right and left coronary arteries, in the distal portions of the fistulas around the crux and in the right atrium. These findings facilitated our diagnosis of right and left coronary arteries-right atrial fistulas. The flow velocity at the ostium of the right coronary artery was highest and nearly the same as the flow velocity (about 2 m/s) obtained by continuous wave Doppler from the maximum point of the thrill. The maximum pressure difference was considered located at this portion. Selective coronary angiography confirmed the right coronary artery and left main trunk-left circumflex coronary artery to be large, elongated and tortuous. These fistulas were communicating with the right atrium. This case demonstrates the usefulness of Doppler echocardiography in the noninvasive diagnosis of coronary arteriovenous fistula.