The Introduction of Human Heme Oxygenase-1 and Soluble Tumor Necrosis Factor-α Receptor Type I With Human IgG1 Fc in Porcine Islets Prolongs Islet Xenograft Survival in Humanized Mice

Apoptosis during engraftment and inflammation induce poor islet xenograft survival. We aimed to determine whether overexpression of human heme oxygenase-1 (HO-1) or soluble tumor necrosis factor-α receptor type I with human IgG1 Fc (sTNF-αR-Fc) in porcine islets could improve islet xenograft survival. Adult porcine islets were transduced with adenovirus containing human HO-1, sTNF-αR-Fc, sTNF-αR-Fc/HO-1 or green fluorescent protein (control). Humanized mice were generated by injecting human cord blood-derived CD34(+) stem cells into NOD-scid-IL-2Rγ(null) mice. Both HO-1 and sTNF-αR-Fc reduced islet apoptosis under in vitro hypoxia or cytokine stimuli and suppressed RANTES induction without compromising insulin secretion. Introduction of either gene into islets prolonged islet xenograft survival in pig-to-humanized mice transplantation. The sTNF-αR-Fc/HO-1 group showed the best glucose tolerance. Target genes were successfully expressed in islet xenografts. Perigraft infiltration of macrophages and T cells was suppressed with decreased expression of RANTES, tumor necrosis factor-α and IL-6 in treatment groups; however, frequency of pig-specific interferon-γ-producing T cells was not decreased, and humoral response was not significant in any group. Early apoptosis of islet cells was suppressed in the treatment groups. In conclusion, overexpression of HO-1 or sTNF-αR-Fc in porcine islets improved islet xenograft survival by suppressing both apoptosis and inflammation. HO-1 or sTNF-αR-Fc transgenic pigs have potential for islet xenotransplantation.

Three-body nonmesonic weak decay of the (Lambda)12C hypernucleus

We have measured the branching ratio of the three-body process in the nonmesonic weak decay of Lambda12C to be 0.29+/-0.13. This result was obtained by reproducing the nucleon and the nucleon pair yields introducing a measured final state interaction. At the same time, we have determined the absolute decay widths, Gamma(n) and Gamma(p), along with Gamma2N, whose relative ratio has been a long-standing puzzle. Including the three-body process, we have successfully reproduced the nucleon energy distribution, the coincidence two-nucleon angular correlation, and the momentum sum distribution simultaneously.

Exclusive measurement of the nonmesonic weak decay of the lambda(5)He hypernucleus

We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay of lambda(5)He formed via the 6Li(pi+, K+) reaction. The energies of the two nucleons and the pair number distributions in the opening angle between them were measured. In both np and nn pairs, we observed a clean back-to-back correlation coming from the two-body weak reactions of lambda p --> np and lambda n --> nn, respectively. The ratio of the nucleon pair numbers was N(nn)/N(np) = 0.45 +/- 0.11(stat) +/- 0.03(syst) in the kinematic region of cos theta(NN) < -0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of gamma(lambda p --> np)/gamma(lambda n --> nn). The ratio is consistent with recent theoretical calculations based on the heavy meson and/or direct-quark exchange picture.

Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.

In situ photoemission study of the room temperature ferromagnet ZnGeP2:Mn

The chemical states of the ZnGeP(2):Mn interface which shows ferromagnetism above room temperature have been studied by photoemission spectroscopy. Mn deposition on the ZnGeP2 substrate heated to 400 degrees C induced Mn substitution for Zn and then the formation of metallic Mn-Ge-P compounds. Depth profile studies have shown that Mn 3d electrons changed their character from itinerant to localized along the depth, and in the deep region, dilute divalent Mn species (<5% Mn) was observed with a coexisting metallic Fermi edge of non-Mn 3d character. The possibility of hole doping through Mn substitution for Ge and/or Zn vacancy is discussed.

Three-dimensional color power Doppler imaging in the assessment of uteroplacental neovascularization in placenta previa increta/percreta

A case of placenta previa increta/percreta was diagnosed at 18 weeks' gestation with the 3-dimensional color power Doppler imaging technique. Unusually extensive uteroplacental vascular network architecture was seen on the 3-dimensional angiohistogram. After appropriate counseling, the patient chose to terminate the pregnancy. A hysterectomy was performed with prophylactic preoperative embolization of internal iliac arteries at 21 weeks' gestation, and histopathologic examination revealed placenta previa increta/percreta. This new 3-dimensional angiohistogram technique allowed us to visualize all 3 orthogonal planes of the angioarchitectural information. It appears to be a useful complementary tool and is likely to play a more defining and clarifying role in assessing the quantification of abnormal uteroplacental neovascularization for patients with placenta previa increta/percreta.

The roles of PDZ-containing proteins in PLC-beta-mediated signaling

Mammalian phospholipase C-beta isozymes are activated by a heterotrimeric GTP-binding protein linked to various cell surface receptors. Recent reports suggest that PDZ domain proteins play a significant role of PDZ-containing proteins in the regulation of mammalian PLC-beta isozymes. PDZ-containing proteins mediate the clustering of receptors and signaling molecules and thereby regulate agonist-induced signal transduction in polarized cells such as neuronal and epithelial cells. NORPA, a Drosophila PLC-beta, is known to be a component of a signaling complex that includes TRP and rhodopsin through interaction with INAD, a PDZ-containing protein. Mammalian PLC-beta1 and -beta2 isoforms interact with a PDZ-containing protein NHERF which is coupled to Trp4, a Ca(2+) channel. In addition, PLC-beta3 specifically interacts with E3KARP, another protein closely related to NHERF, through its C-terminal PDZ-binding motif. E3KARP up-regulates the PLC-beta3 activation coupled to muscarinic receptor. In this review, the role of signaling complexes mediated by PDZ-containing proteins in the regulation of PLC-beta isoforms will be discussed.

Molecular interactions between poly(ADP-ribose) polymerase (PARP I) and topoisomerase I (Topo I): identification of topology of binding

The molecular interactions of poly(ADP-ribose) polymerase I (PARP I) and topoisomerase I (Topo I) have been determined by the analysis of physical binding of the two proteins and some of their polypeptide components and by the effect of PARP I on the enzymatic catalysis of Topo I. Direct association of Topo I and PARP I as well as the binding of two Topo I polypeptides to PARP I are demonstrated. The effect of PARP I on the 'global' Topo I reaction (scission and religation), and the activation of Topo I by the 36 kDa polypeptide of PARP I and catalytic modifications by poly(ADP-ribosyl)ation are also shown. The covalent binding of Topo I to circular DNA is activated by PARP I similar to the degree of activation of the 'global' Topo I reaction, whereas the religation of DNA is unaffected by PARP I. The geometry of PARP I-Topo I interaction compared to automodified PARP I was reconstructed from direct binding assays between glutathione S-transferase fusion polypeptides of Topo I and PARP I demonstrating highly selective binding, which was correlated with amino acid sequences and with the 'C clamp' model derived from X-ray crystallography.

An anti-apoptotic protein human survivin is a direct inhibitor of caspase-3 and -7

Survivin, an apoptosis inhibitor/cell-cycle regulator, is critically required for suppression of apoptosis and ensuring normal cell division in the G2/M phase of the cell cycle. It is highly expressed in a cell cycle-regulated manner and localizes together with caspase-3 on microtubules within centrosomes. Whether survivin is a physiologically relevant caspase inhibitor has been unclear due to the difficulties with obtaining correctly folded survivin and finding the right conditions for inhibition assay. In this study, recombinant, active human survivin was expressed in Escherichia coli and purified to homogeneity. The protein, existing as a homodimer in solution, binds caspase-3 and -7 tightly with dissociation constants of 20.9 and 11.5 nM, respectively, when evaluated by surface plasmon resonance spectroscopy. Consistently, survivin potently inhibits the cleavage of a physiological substrate poly(ADP-ribose) polymerase and an artificial tetrapeptide by caspase-3 and -7 in vitro with apparent inhibition constants of 36.0 and 16.5 nM, respectively. The data suggest that sequestering caspase-3 and -7 in inhibited states on microtubules is at least one mechanism of survivin in the suppression of default apoptosis in the G2/M phase. The localization of survivin on microtubules, which is essential for its function, should increase the protective activity at the action site.

An anti-apoptotic protein human survivin is a direct inhibitor of caspase-3 and -7

Survivin, an apoptosis inhibitor/cell-cycle regulator, is critically required for suppression of apoptosis and ensuring normal cell division in the G2/M phase of the cell cycle. It is highly expressed in a cell cycle-regulated manner and localizes together with caspase-3 on microtubules within centrosomes. Whether survivin is a physiologically relevant caspase inhibitor has been unclear due to the difficulties with obtaining correctly folded survivin and finding the right conditions for inhibition assay. In this study, recombinant, active human survivin was expressed in Escherichia coli and purified to homogeneity. The protein, existing as a homodimer in solution, binds caspase-3 and -7 tightly with dissociation constants of 20.9 and 11.5 nM, respectively, when evaluated by surface plasmon resonance spectroscopy. Consistently, survivin potently inhibits the cleavage of a physiological substrate poly(ADP-ribose) polymerase and an artificial tetrapeptide by caspase-3 and -7 in vitro with apparent inhibition constants of 36.0 and 16.5 nM, respectively. The data suggest that sequestering caspase-3 and -7 in inhibited states on microtubules is at least one mechanism of survivin in the suppression of default apoptosis in the G2/M phase. The localization of survivin on microtubules, which is essential for its function, should increase the protective activity at the action site.

Direct interaction of SOS1 Ras exchange protein with the SH3 domain of phospholipase C-gamma1

A recent report that microinjection of the SH3 domain of PLC-gamma1 could induce DNA synthesis raised the functional importance of the SH3 domain of PLC-gamma1 in mitogenic signaling. In this report, we provide evidence that SOS1, a p21Ras-specific guanine nucleotide exchange factor, directly binds to the SH3 domain of PLC-gamma1, and that the SH3 domain of PLC-gamma1 is involved in SOS1-mediated p21Ras activation. SOS1 was coprecipitated with the GST-fused SH3 domain of PLC-gamma1 in vitro. The interaction between SOS1 and the PLC-gamma1 SH3 domain is mediated by direct physical interaction. The carboxyl-terminal proline-rich domain of SOS1 is involved in the interaction with the PLC-gamma1 SH3 domain. Moreover, PLC-gamma1 could be co-immunoprecipitated with SOS1 antibody in cell lysates. From transient expression studies, we could demonstrate that the SH3 domain of PLC-gamma1 is necessary for the association with SOS1 in vivo. Intriguingly, overexpression of the SH3 domain of PLC-gamma1, lipase-inactive PLC-gamma1, or wild-type PLC-gamma1 elevated p21Ras activity and ERK activity when compared with vector transfected cells. The PLC-gamma1 mutant lacking the SH3 domain could not activate p21Ras. p21Ras activities in cell lines overexpressing either PLC-gamma1 or the SH2-SH2-SH3 domain of PLC-gamma1 were elevated about 2-fold compared to vector transfected cells. This study is the first to demonstrate that the PLC-gamma1 SH3 domain enhances p21Ras activity, and that the SH3 domain of PLC-gamma1 may be involved in the SOS1-mediated signaling pathway.

Regulation of phospholipase C-beta 3 activity by Na+/H+ exchanger regulatory factor 2

Among the phospholipase C that catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate, four mammalian phospholipase C-beta (PLC-beta) isotypes (isotypes 1-4) are activated through G protein-coupled receptors (GPCRs). Although the regulation of the PLC-betas by GPCRs and heterotrimeric G proteins has been extensively studied, little is known about the molecular determinants that regulate their activity. The PLC-beta isozymes carry a putative PSD-95/Dlg/ZO-1 (PDZ) binding motif (X(S/T)X(V/L)COOH) at their carboxyl terminus, which is implicated in specific interactions with anchor proteins. Using the yeast two-hybrid system, we identified Na(+)/H(+) exchanger regulatory factor 2 (NHERF2) as a protein that interacted with a C-terminal heptapeptide of PLC-beta3. Immunoprecipitation studies revealed that NHERF2 interacts specifically with PLC-beta3, but not with other PLC-beta isotypes. Furthermore, PLC-beta3 interacted with NHERF2 rather than with other PDZ-containing proteins. This interaction required the COOH-terminal NTQL sequence of PLC-beta3 and the second PDZ domain of NHERF2. Interestingly, NHERF2 potentiated the PLC-beta activation by carbachol in COS7 and HeLa cells, while mutant NHERF2, lacking the second PDZ domain, had no such effect. Taken together, the data suggest that NHERF2 may act as a modulator underlying the process of PLC-beta3-mediated signaling.

The SH2-SH2-SH3 domain of phospholipase C-gamma1 directly binds to translational elongation factor-1alpha

Phospholipase C-gamma1 (PLC-gamma1) is a lipase that hydrolyzes PIP2 to generate two second messengers, IP3 and DAG. By using the yeast two-hybrid system, we identified the translational elongation factor-1alpha (EF-1alpha) as a binding protein of PLC-gamma1 from the human B-lymphocyte library. Direct interaction between EF-1alpha and PLC-gamma1 was confirmed by the in vitro binding experiment using purified PLC-gamma1. Furthermore, from the in vitro binding experiment, we could demonstrate that the carboxyl terminal region of EF-1alpha is involved in the interaction with PLC-gamma1, and that both SH2 and SH3 domains of PLC-gamma1 are required for the interaction with EF-1alpha. In vivo interaction between EF-1alpha and PLC-gamma1 was confirmed by the immunoprecipitation experiment using anti-EF-1alpha antibody. The interaction between EF-1alpha and PLC-gamma1 was enhanced by EGF-treatment. Taken together, we suggest that EF-1alpha might play a role in PLC-gamma1-mediated signal transduction.

Characterization of the Shank family of synaptic proteins. Multiple genes, alternative splicing, and differential expression in brain and development

Shank1, Shank2, and Shank3 constitute a family of proteins that may function as molecular scaffolds in the postsynaptic density (PSD). Shank directly interacts with GKAP and Homer, thus potentially bridging the N-methyl-D-aspartate receptor-PSD-95-GKAP complex and the mGluR-Homer complex in synapses (Naisbitt, S., Kim, E., Tu, J. C. , Xiao, B., Sala, S., Valtschanoff, J., Weinberg, R. J., Worley, P. F., and Sheng, M. (1999) Neuron 23, 569-582; Tu, J. C., Xiao, B., Naisbitt, S., Yuan, J. P., Petralia, R. S., Brakeman, P., Doan, A., Aakalu, V. K., Lanahan, A. A., Sheng, M., and Worley, P. F. (1999) Neuron 23, 583-592). Shank contains multiple domains for protein-protein interaction including ankyrin repeats, an SH3 domain, a PSD-95/Dlg/ZO-1 domain, a sterile alpha motif domain, and a proline-rich region. By characterizing Shank cDNA clones and RT-PCR products, we found that there are four sites for alternative splicing in Shank1 and another four sites in Shank2, some of which result in deletion of specific domains of the Shank protein. In addition, the expression of the splice variants is differentially regulated in different regions of rat brain during development. Immunoblot analysis of Shank proteins in rat brain using five different Shank antibodies reveals marked heterogeneity in size (120-240 kDa) and differential spatiotemporal expression. Shank1 immunoreactivity is concentrated at excitatory synaptic sites in adult brain, and the punctate staining of Shank1 is seen in developing rat brains as early as postnatal day 7. These results suggest that alternative splicing in the Shank family may be a mechanism that regulates the molecular structure of Shank and the spectrum of Shank-interacting proteins in the PSDs of adult and developing brain.

Dynamic helical biphasic CT emerges as a potential tool for the diagnosis of proximal arterioportal shunting

BACKGROUND/AIMS

This article reports our preliminary observation regarding the diagnostic ability of dynamic helical biphasic computed tomography (CT) for proximal arterioportal shunting in hepatoma patients as compared with that of conventional angiography.

METHODOLOGY

Three hundred and sixty patients with clinically-suspected liver lesions received both dynamic helical biphasic CT scan and conventional angiography of the liver. The criteria for diagnosis of proximal arterioportal (AP) shunting in dynamic helical biphasic CT included early and strong enhancement of main portal vein or its major branches approaching the density of the aorta, or enhancement of the portal vein earlier than opacification of the splenic vein and superior mesenteric vein in the arterial phase. The angiographic diagnosis of proximal AP shunting was made if there was early opacification of the main portal vein or its major branches in the arterial phase. Peripheral subsegmental small AP shunting was excluded from our study. The existence and extent of AP shunting were compared in these two imaging modalities.

RESULTS

Dynamic helical biphasic CT scan demonstrated proximal AP shunting in 23 patients. All of these patients harbored hepatoma. Conventional angiography showed proximal AP shunting in 20 patients, which were all positive on dynamic helical CT. Dynamic helical biphasic CT demonstrated the presence of proximal AP shunting in 3 more patients than conventional angiography did. The extent of AP shunting was well correlated between these two imaging modalities in 17 patients.

CONCLUSIONS

From our preliminary experience, the diagnostic accuracy of dynamic helical biphasic CT for proximal AP shunting in patients with hepatoma seemed to be comparable to, or even surpassed that of conventional angiography. It seems that faint AP shunting in patients with large hepatoma might be missed by conventional angiography.

Pictorial review: Radiological diagnosis of duodenal abnormalities

This article depicts the radiological findings of many common gastrointestinal entities. Specifically, examples of disease processes that affect the stomach, gall bladder, small intestine, pancreas and colon are shown. In most cases there is correlation between ultrasound, computed tomography (CT) and fluoroscopic imaging. The major emphasis of the article, however, is to demonstrate classic barium imaging of a large number of gastrointestinal disease processes.

Radiologic and pathologic correlation of adenomyomatosis of the gallbladder

BACKGROUND

To demonstrate the radiologic-pathologic correlation of adenomyomatosis of gallbladder (GBA) and emphasize the role of high-resolution real-time ultrasound (RTUS) in the diagnosis of GBA.

METHODS

Ten (four male and six female, mean age = 49 years) patients with proven GBA (three diffuse, three segmental, and four fundal) diagnosed by histopathology or confirmed by oral cholecystography (OCG) were reviewed. Radiologic studies included OCG (n = 8), RTUS (n = 8), and computed tomography (CT; n = 4). Six patients subsequently underwent cholecystectomy.

RESULTS

Histopathologic correlation between pathologic specimens and OCG, RTUS, and CT was possible in six patients. The diagnostic criteria with ultrasound included numerous tiny intramural cysts containing echogenic foci with reverberation artifacts and associated segmental or diffuse gallbladder wall thickening. OCG with fatty meal demonstrated intramural diverticula. Localized fundal GBA was better visualized on RTUS and CT scan than on OCG.

CONCLUSION

Accurate diagnosis of GBA may be made by either OCG or high-resolution RTUS preoperatively. CT scan may used as an alternative method to help make the diagnosis in equivocal cases.

Normal and variant anatomy of hepatic arteries: angiographic experience

BACKGROUND

Anatomic variation of hepatic arteries is reported to occur in 25-50% of the general population. Knowledge of the existing variations is important in planning and conducting surgical or radiologic procedures in the upper abdomen, such as liver transplantation and transarterial chemo-embolization (TACE).

METHODS

Based on data from 321 patients undergoing upper abdominal arteriography, hepatic artery anatomy was analyzed and classified into three groups (single, double and multiple hepatic arteries at hepatic hilum) according to Suzuki's classification. Each group was subdivided into three types (celiac, mesenteric and mixed types) according to the origin of the hepatic arteries. The variations within each type were recorded.

RESULTS

Two hundred and sixty one patients (68.%) had single hepatic arteries. One hundred and five patients (27.6%) had double hepatic arteries and only fifteen patients had multiple hepatic arteries. All of these variants, including twenty subtypes, were identified.

CONCLUSIONS

This study, based on Suzuki's classification, provides basic data for the anatomic variations of hepatic arteries for the Chinese population in Taiwan.

Selective intra-arterial calcium injection in the investigation of adult nesidioblastosis: a case report

A 69-year-old man with recurrent hypoglycaemia had inappropriately elevated plasma insulin level during a symptomatic hypoglycaemia, but had a negative prolonged fast. Computerized tomography (CT) of the abdomen revealed a nodular lesion over the body of pancreas, whereas pancreatic arteriography failed to show tumour blush. Hence, arterial stimulation (with calcium) and venous sampling (ASVS) was performed and a brisk response of plasma insulin level was found when calcium was injected both into the splenic and the superior mesenteric arteries. Since no tumour was found during the operation, the patient received subtotal distal pancreatectomy. Pathological examination of the resected tissue disclosed a typical finding of nesidioblastosis. We suggest that selective intra-arterial calcium injection with hepatic venous sampling for insulin gradients is useful for the diagnosis of adult nesidioblastosis.

Significance of isolated gastric varices among Chinese patients

BACKGROUND

Isolated gastric varices rarely occurs, and was considered as a hint of pancreatic disease rather than liver cirrhosis. Recently, the frequency of acute gastrointestinal bleeding secondary to isolated gastric varices tended to increase among cirrhotic patients. We therefore conducted this retrospective study to analyze its possible etiologies.

METHODS

Thirty-six cases of isolated gastric varices were found in an extensive review of the endoscopic records at our hospital from 1984 to 1993. Gastric varices developed after injection sclerotherapy of esophageal varices were excluded. Medical records were reviewed to determine their etiologies.

RESULTS

The underlying disorders of these 36 patients included liver cirrhosis in 26 patients (72.2%), pancreatic diseases in 7 patients (19.4%), myelofibrosis in 1 patient (2.7%), and unknown cause in 2 patients (5.5%). Among those with liver cirrhosis, portal hemodynamic study conducted in 5 patients to find all with a high level of portal venous pressure; angiography conducted in 5 patients also found all with gastric varices. Among those with pancreatic diseases, angiography and/or splenoportography was conducted in 5 patients to evidence all with gastric varices, splenic vein obstruction and splenomegaly.

CONCLUSIONS

Isolated gastric varices identified in endoscopy can first strongly suggests the presence of liver cirrhosis with portal hypertension. Pancreatic diseases complicating with splenic vein obstruction is the second possible underlying etiology.

Intraductal mucin-hypersecreting papillary adenocarcinoma of the pancreas: a case report

A 68-year-old male was admitted with jaundice and abdominal fullness. Abdominal ultrasonography and computed tomography (CT) scan showed a diffusely dilated main pancreatic duct (MPD) with microcystic lesions over the pancreatic head and dilatation of the biliary tract. Duodenoscopy revealed mucin secretion at the orifice of the papilla of Vater. Findings of endoscopic retrograde cholangiopancreatography (ERCP) were compatible with a mucinous tumor of pancreas invading the common bile duct. The patient was treated with a modified Whipple's operation. Pathological diagnosis was papillomatosis with papillary adenocarcinoma of the pancreas.

[Computed tomography for evaluation of hepatocellular carcinoma after treatment with transarterial chemoembolization]

Totally 135 series of computed tomography (CT) and angiographic examination were performed in 53 patients with proved hepatoma treated by TAE. CT examination was performed four to six weeks after TAE, and a comparative angiographic examination was performed within three weeks after CT examination. The pictures of CT scanning were read to determine 1). the grading of lipiodol retention inside the tumor, 2). the presence/absence of filling defect in the tumor margins coated by lipiodol, 3). the presence/absence of residual tumor tissue within or surrounding the main tumor, and 4). the presence/absence of developed satellite nodules. In comparison with angiographic findings, CT demonstrated 96.3% specificity and 58.2% sensitivity in the grading of lipiodol filling, and 96.3% specificity and 65.7% sensitivity in the tumor margins of lipiodol coating. However, it was difficult for CT to detect small nodules, especially those less than 1 cm in diameter. We find no statistically significant association between newly developed satellite nodules and grading of lipiodol retention inside the tumor or tumor margins of lipiodol coating. Therefore, when CT pictures reveal filling defect over the margins of the tumor coated by lipiodol or less-than-50% lipiodol filling inside the tumor, repeated angiography and further treatment with TAE are suggested.