A positive role for histone acetylation in transcription factor access to nucleosomal DNA

Acetylation of the N-terminal tails of the core histones directly facilitates the recognition by TFIIIA of the 5S RNA gene within model chromatin templates. This effect is independent of a reduction in the extent of histone-DNA interactions or a change in DNA helical repeat; it is also independent of whether a histone tetramer or octamer inhibits TFIIIA binding. Removal of the N-terminal tails from the core histones also facilitates the association of TFIIIA with nucleosomal templates. We suggest that the histone tails have a major role in restricting transcription factor access to DNA and that their acetylation releases this restriction by directing dissociation of the tails from DNA and/or inducing a change in DNA configuration on the histone core to allow transcription factor binding. Acetylation of core histones might be expected to exert a major influence on the accessibility of chromatin to regulatory molecules.

The dissected aorta: part III. Anatomy and radiologic diagnosis of branch-vessel compromise

PURPOSE

To determine the anatomic, hemodynamic, and radiologic characteristics of branch-vessel compromise in patients with aortic dissection.

MATERIALS AND METHODS

Sixty-two patients with aortic dissection were evaluated with aortography (n = 62), intravascular ultrasound (US) (n = 35), and manometry (n = 56). Branch-vessel compromise with ischemia was suspected in 40 of these patients. Radiologic and manometric findings were correlated with clinical findings of ischemia. Femoral artery pulse strength was correlated with access from the respective femoral artery to the true and false lumina of the dissected aorta.

RESULTS

Twenty-six of 40 patients suspected of having ischemia had angiographic evidence of branch-vessel compromise, and intravascular US helped identify two types of branch-vessel compromise in them: static (dissection intersected and narrowed the vessel origin) and dynamic (dissection spared the vessel origin, but the dissection flap appeared to compress the true lumen at or above the origin and covered the origin). False-lumen pressure in classic dissections exceeded (n = 16) or equaled (n = 30) true-lumen pressure. Branch vessels that arose exclusively from the false lumen were well perfused. Findings of a dissection flap oriented concave toward the false lumen were 91% sensitive and 72% specific for a true-lumen pressure deficit.

CONCLUSION

Intravascular US and manometric findings clarify the mechanisms of branch-vessel compromise after aortic dissection and provide a rational guide for percutaneous treatment.

Vascular endothelial growth factor governs endothelial nitric-oxide synthase expression via a KDR/Flk-1 receptor and a protein kinase C signaling pathway

The mechanism by which vascular endothelial growth factor (VEGF) regulates endothelial nitric-oxide synthase (eNOS) expression is presently unclear. Here we report that VEGF treatment of bovine adrenal cortex endothelial cells resulted in a 5-fold increase in both eNOS protein and activity. Endothelial NOS expression was maximal following 2 days of constant VEGF exposure (500 pM) and declined to base-line levels by day 5. The elevated eNOS protein level was sustained over the time course if VEGF was co-incubated with L-N(G)-nitroarginine methyl ester, a competitive eNOS inhibitor. Addition of S-nitroso-N-acetylpenicillamine, a nitric oxide donor, prevented VEGF-induced eNOS up-regulation. These data suggest that nitric oxide participates in a negative feedback mechanism regulating eNOS expression. Various approaches were used to investigate the role of the two high affinity VEGF receptors in eNOS up-regulation. A KDR receptor-selective mutant increased eNOS expression, whereas an Flt-1 receptor-selective mutant did not. Furthermore, VEGF treatment increased eNOS expression in a KDR but not in an Flt-1 receptor-transfected porcine aorta endothelial cell line. SU1498, a selective inhibitor of the KDR receptor tyrosine kinase, blocked eNOS up-regulation, thus providing further evidence that the KDR receptor signals for eNOS up-regulation. Finally, treatment of adrenal cortex endothelial cells with VEGF or phorbol ester resulted in protein kinase C activation and elevated eNOS expression, whereas inhibition of protein kinase C with isoform-specific inhibitors abolished VEGF-induced eNOS up-regulation. Taken together, these data demonstrate that VEGF increases eNOS expression via activation of the KDR receptor tyrosine kinase and a downstream protein kinase C signaling pathway.

Functional diversification of the two C-class MADS box genes OSMADS3 and OSMADS58 in Oryza sativa

The C-class MADS box gene AGAMOUS (AG) plays crucial roles in Arabidopsis thaliana development by regulating the organ identity of stamens and carpels, the repression of A-class genes, and floral meristem determinacy. To examine the conservation and diversification of C-class gene function in monocots, we analyzed two C-class genes in rice (Oryza sativa), OSMADS3 and OSMADS58, which may have arisen by gene duplication before divergence of rice and maize (Zea mays). A knockout line of OSMADS3, in which the gene is disrupted by T-DNA insertion, shows homeotic transformation of stamens into lodicules and ectopic development of lodicules in the second whorl near the palea where lodicules do not form in the wild type but carpels develop almost normally. By contrast, RNA-silenced lines of OSMADS58 develop astonishing flowers that reiterate a set of floral organs, including lodicules, stamens, and carpel-like organs, suggesting that determinacy of the floral meristem is severely affected. These results suggest that the two C-class genes have been partially subfunctionalized during rice evolution (i.e., the functions regulated by AG have been partially partitioned into two paralogous genes, OSMADS3 and OSMADS58, which were produced by a recent gene duplication event in plant evolution).

Development of a novel, Ins(1,4,5)P3-specific binding assay. Its use to determine the intracellular concentration of Ins(1,4,5)P3 in unstimulated and vasopressin-stimulated rat hepatocytes

The binding of [3H]Ins(1,4,5)P3 to bovine adrenocortical microsomes has been shown to be rapid, reversible and saturable. The microsomal preparation contained a single population of high affinity sites (KD = 6.82+/-2.3 nM, Bmax = 370+/-38 fmol/mg protein). The binding site was shown to exhibit positional specificity with respect to inositol trisphosphate binding, i.e. Ins(2,4,5)P3 was able to compete with [3H]Ins(1,4,5)P3 whereas Ins(1,3,4)P3 was not. Ins(1,3,4,5)P4 showed a similar affinity for the receptor as Ins(2,4,5)P3 whereas the other inositol phosphates tested, ATP, GTP and 2,3-DPG, were poor competitors. [3H]Ins(1,4,5)P3-binding was independent of free Ca2+ concentrations. The adrenocortical microsomal preparation has been incorporated into an assay which has been used to determine the basal and vasopressin-stimulated content of neutralised acid extracts of rat hepatocytes. Intracellular concentrations of Ins(1,4,5)P3 were calculated to be 0.22+/-0.15 microM basal and 2.53+/-1.8 microM at peak stimulation. This assay provides a simple, specific and quantitative method for the measurement of Ins(1,4,5)P3 concentrations in the picomolar range.

The dissected aorta: percutaneous treatment of ischemic complications--principles and results

PURPOSE

Describe the principles and results of percutaneous treatment of ischemic complications of aortic dissection.

MATERIALS AND METHODS

Twenty-four patients with aortic dissection complicated by ischemic compromise of the liver or bowel (n = 15), kidney (n = 18), or lower extremity (n = 13) were evaluated by means of aortography, intravascular ultrasound, and manometry, and were treated percutaneously. Visceral arteries were classified as obstructed or nonobstructed. Obstruction was classified as static, in which the dissecting hematoma extended into and narrowed the lumen of a branch artery, or dynamic, in which the dissection flap prolapsed into the vessel origin or narrowed the true lumen (TL) above it. Treatment consisted of vascular stents alone (n = 4), or balloon fenestration (n = 20) without (n = 8) or with (n = 12) vascular stents.

RESULTS

Obstruction was present in 77 arteries and was static in 12 arteries, dynamic in 45 arteries, static and dynamic in 17 arteries, and indeterminate in three arteries. Percutaneous treatment did not alter false lumen (FL) pressure, but reduced the peak systolic interluminal pressure gradient from 28 mm Hg to 2 mm Hg and restored flow in 71 of 77 arteries (92%). Six patients died within 30 days (25% operative mortality), none as a result of the procedure. Two additional patients died in follow-up from complications of an expanding FL. Technical complications in two patients due to altered hemodynamics after initial intervention were recognized and corrected percutaneously during the same procedure.

CONCLUSIONS

Percutaneous fenestration and endovascular stent deployment are indicated to restore blood flow to arteries compromised by aortic dissection. The prognosis of patients is related to the ischemic injury sustained prior to the percutaneous interventional procedure and, in patients with acute type I dissection who have not undergone surgery, to the preoperative stability of the FL.

Homologous up-regulation of KDR/Flk-1 receptor expression by vascular endothelial growth factor in vitro

We investigated the possibility that vascular endothelial growth factor (VEGF) treatment could regulate KDR/Flk-1 receptor expression in endothelial cells. Bovine adrenal cortex endothelial cells were incubated with 200 pM rhVEGF165 for 0-7 days. Western blot analysis showed a 3-5-fold increase in total KDR protein following 4-day VEGF treatment. Scatchard analysis revealed that VEGF induced a 2-3-fold increase in high affinity receptor number (5.0 x 10(4)/cell versus 2. 4 x 10(4)/cell) without significantly affecting receptor binding affinity (Kd 76 pM versus 72 pM). Quantitative polymerase chain reaction analysis demonstrated a 3-fold increase in KDR mRNA levels following VEGF exposure. VEGF-induced KDR expression primarily occurred at the transcriptional level as demonstrated by a luciferase reporter assay system. Receptor selective mutants with wild-type KDR binding and decreased Flt-1 binding also induced KDR up-regulation; in contrast, mutants with decreased KDR binding and wild-type Flt-1 binding did not, suggesting that KDR receptor signaling mediated the increase in KDR expression. Inhibition of tyrosine kinase, Src tyrosine kinase, protein kinase C, and mitogen-activated protein kinase activities all blocked VEGF-induced KDR up-regulation. Finally, co-incubation of nitric-oxide synthase inhibitors with VEGF had no significant effect on KDR expression, but 100 microM sodium nitroprusside, a NO donor, significantly inhibited VEGF-induced KDR up-regulation, indicating that NO negatively regulates KDR expression. In conclusion, our data demonstrate that VEGF binding to the KDR receptor tyrosine kinase results in an increase in KDR receptor gene transcription and protein expression. Thus, KDR up-regulation induced by VEGF may represent an important positive feedback mechanism for VEGF action in tumor and ischemia-induced angiogenesis.

Combined transcatheter arterial chemoembolization and local radiotherapy of unresectable hepatocellular carcinoma

PURPOSE

The best prognosis in hepatocellular carcinoma (HCC) can be achieved with surgical resection; however, the number of resected cases are limited due to advanced lesions or associated liver disease. The purpose of this study was to investigate the efficacy and toxicity of a prospective trial of combined transcatheter arterial chemoembolization (TACE) and local radiotherapy (RT) in unresectable HCC.

METHODS AND MATERIALS

Patients with histologically proven unresectable HCC due to either advanced lesions or associated cirrhosis were eligible. From March 1992 to August 1994, 30 patients were entered into this study. TACE was performed with Lipiodol (5 ml) and doxorubicin (Adriamycin ; 50 mg), followed by gelatin sponge particle (Gelfoam) embolization. Local RT was started within 7-10 days following TACE. Mean tumor dose was 44.0+/-9.3 Gy in daily 1.8 Gy fractions. Response was assessed by computerized tomography (CT) scan 4-6 weeks following completion of the treatment and then at 1-3-month intervals. Survival was calculated from the start of TACE using the Kaplan-Meier method.

RESULTS

An objective response was observed in 19 patients, giving a response rate of 63.3%. Distant metastasis occurred in 10 patients, with 8 in the lung only and 2 in both lung and bone. Survival rates at 1, 2, and 3 years were 67%, 33.3%, and 22.2%, respectively. Median survival was 17 months. There were 6 patients surviving more than 3 years. Toxicity included transient elevation of liver function tests in all patients, fever in 20, thrombocytopenia in 4, and nausea and vomiting in 1. There was no treatment-related death.

CONCLUSION

Combined TACE and local RT is feasible and tolerable. It gives a 63.3% response rate with median survival of 17 months. We feel that this regimen would be a new promising modality in unresectable HCC. Further study is required to compare the therapeutic efficacy of this regimen to TACE alone.

Initiation of mitochondrial DNA replication by transcription and R-loop processing

The mitochondrial genome of eukaryotic cells is maintained by a mechanism distinct from that employed in the nucleus. Mitochondrial DNA replication at the leading-strand origin is coupled to transcription through the formation of an RNA-DNA hybrid known as an R-loop. In vivo and in vitro evidence has implicated an RNA processing enzyme, RNase MRP, in primer maturation. In our investigation of mammalian RNase MRP, we have analyzed its specific endoribonuclease activity on model R-loops. We demonstrate here that human RNase MRP cleaves this distinctly configured substrate at virtually all of the major DNA replication sites previously mapped in vivo. We further show that the processed RNA products remain stably base-paired to the template DNA strand and are functional for initiating DNA synthesis on a closed circular plasmid. Thus, in vitro initiation of leading-strand mtDNA synthesis requires only the actions of RNA polymerase and RNase MRP for the generation of replication primers.

Diagnostic accuracy of mini-mental status examination and revised hasegawa dementia scale for Alzheimer's disease

To compare the diagnostic accuracies of the Revised Hasegawa Dementia Scale (HDS-R) and Mini-Mental Status Examination (MMSE) for Alzheimer's diseases (AD), we administered them simultaneously to 82 AD patients and 82 age- and sex-matched nondemented control subjects. The area under the receiver operator curve (AUC) for AD of the HDS-R (AUC(HDS-R)) and MMSE (AUC(MMSE)) were bigger than 0.90 indicating that both tests are useful for detecting AD. However, AUC(HDS-R) (0.952) was significantly larger than that of the AUC(MMSE )(0.902) regardless of the educational level of the subjects, indicating that the HDS-R is more accurate than MMSE in diagnosing AD. Moreover, the superiority of the HDS-R (AUC(HDS-R) = 0.894) to the MMSE (AUC(MMSE) = 0.704) remained significant in mild AD patients alone, who are the focus of screening. In conclusion, the HDS-R is better than the MMSE as a screening instrument for AD.

Local radiotherapy for unresectable hepatocellular carcinoma patients who failed with transcatheter arterial chemoembolization

PURPOSE

The purpose of this study was to investigate the efficacy of local radiotherapy (RT) as a salvage treatment for unresectable hepatocellular carcinoma (HCC) patients who failed with transcatheter arterial chemoembolization (TACE).

METHODS AND MATERIALS

Patients with unresectable HCC who had been treated with and eventually failed with TACE were eligible. The judgment of TACE failure was based on incomplete tumor filling of lipiodol-adriamycin mixture on either angiography or computed tomography (CT) scan. From January 1993 to December 1997, 27 patients were entered into this study. They had UICC Stage III (17) or IVA (10) disease, with a mean tumor size of 7.2 +/- 2.9 cm. Local RT was done, with a mean tumor dose of 51.8 +/- 7.9 Gy, in daily 1.8-Gy fractions using a 10- or 6-MV linear accelerator. Survival was calculated from both the diagnosis and the start of RT using the Kaplan-Meier method.

RESULTS

An objective response was observed in 16 of 24 patients (66.7%) including 1 CR. Intrahepatic metastasis was noted outside the RT field in 10 patients (37.0%). Extrahepatic distant metastasis occurred in 4 patients. Survival rates at 1, 2, and 3 years were 85. 2%, 58.1%, and 33.2%, respectively, from the diagnosis and 55.9%, 35. 7%, and 21.4%, respectively, from the start of RT. The median survivals were 26 months from the diagnosis and 14 months from the start of RT. Acute toxicity involved alteration in liver function test (13 patients) and thrombocytopenia (2 patients). Subacute and chronic toxicity involved gastroduodenal ulcer (3 patients) and duodenitis (2 patients). There was no treatment-related death.

CONCLUSION

In unresectable HCC patients who failed with TACE, local RT induced a substantial tumor response of 66.7%, with a 3-year survival rate of 21.4% and a median survival time of 14 months. Toxicity was significant but manageable. Although we do not know if there is survival benefit through this treatment, local RT in these patients seems to be valuable as a salvage for TACE-failed HCC.

Mobilization of endothelial progenitor cells in fracture healing and distraction osteogenesis

INTRODUCTION

Fracture healing and distraction osteogenesis (DO) are unique postnatal bone formation processes, and neovascularization is critically required for successful bone regeneration. We investigated endothelial progenitor cell (EPC) mobilization during bone regeneration, and the possible contribution of EPCs to increased vascularization and new bone formation, especially in DO.

METHODS

Mouse tibia fracture and rat tibia DO models were used in this study. The proportion of EPCs among the peripheral and splenic mononuclear cells (MNCs) was determined by examining the endothelial lineage staining characteristics and EPC cell surface markers. Messenger RNA expression of molecules related to EPC mobilization and homing at the fracture site were analyzed by ribonuclease protection assay and reverse-transcription polymerase chain reaction. In the rat tibia DO model, we measured blood flow during DO, and determined the distribution of ex vivo-expanded and intravenously-infused EPCs.

RESULTS

The proportion of EPCs among the peripheral and splenic MNCs increased after fracture, peaked on post-fracture day 3, and returned to basal levels during the healing period. Messenger RNA expression of EPC mobilizing cytokines such as vascular endothelial growth factor (VEGF), stem cell factor, monocyte chemoattractant protein-1, and stromal cell-derived factor-1, were upregulated at the fracture callus. The plasma VEGF levels peaked prior to the increase in the EPC proportion. Adhesion molecules involved in EPC homing were expressed at the fracture callus. In the DO model, the temporal pattern of the increase in the EPC proportion was similar to that in the fracture healing model, but the EPC proportion increased again during the distraction and consolidation phases. The distraction gap was relatively ischemic during the distraction phase and blood flow increased profusely later in the consolidation phase. The number of EPCs homing to the bone regeneration site in the DO model correlated with the number of transplanted EPCs in a dose-dependent manner.

CONCLUSIONS

These findings suggest that signals from the bone regeneration site mobilize EPCs from the bone marrow into the peripheral circulation. Increased EPC mobilization and homing may contribute to neovascularization and thus to new bone formation in fracture healing and DO.

Aortic and arterial aneurysms in behçet disease: management with stent-grafts--initial experience

PURPOSE

To assess the application of stent-grafts in the management of aortic and arterial aneurysms in patients with Behçet disease.

MATERIALS AND METHODS

Nine aneurysms in seven patients were managed with various types of stent-grafts. Diagnoses were based on clinical findings. The aortic aneurysms (n = 3) were thoracic (n = 1), suprarenal (n = 1), or infrarenal (n = 1). The arterial aneurysms (n = 6) were in the right and left subclavian (n = 2), right common carotid (n = 2), right brachiocephalic (n = 1), or left common iliac arteries (n = 1). A tandem connection of Gianturco stent covered with polytetrafluorethylene was placed in three aneurysms, and a balloon-expandable stent was placed in six.

RESULTS

The stent-graft was successfully placed in all patients. Immediate follow-up angiography revealed complete exclusion of the aneurysm in all cases. Follow-up computed tomography performed 3 days to 2 weeks later revealed complete exclusion and thrombosis of the aneurysm and patency of the stent-graft in six patients. In one patient, total occlusion of the artery with a stent occurred due to flow disturbance caused by double lesions. During follow-up (range, 6-59 months; mean, 28 months), the aneurysm resolved and completely regressed in four patients. A recurrent aneurysm at the distal margin of previously inserted stent-graft was successfully managed with an additional stent-graft.

CONCLUSION

The findings in this initial experience suggest that stent-graft insertion may be a safe and effective alternative to surgical treatment of aortic and arterial aneurysms in patients with Behçet disease.

Regional pattern of white matter microstructural changes in normal aging, MCI, and AD

OBJECTIVE

To cross-sectionally compare the regional white matter fractional anisotropy (FA) of cognitively normal (CN) older individuals and patients with mild cognitive impairment (MCI) and Alzheimer disease (AD), separately focusing on the normal-appearing white matter (NAWM) and white matter hyperintensities (WMH), and to test the independent effects of presumed degenerative and vascular process on FA differences.

METHODS

Forty-seven patients with AD, 73 patients with MCI, and 95 CN subjects received diffusion tensor imaging and vascular risk evaluation. To properly control normal regional variability of FA, we divided cerebral white matter into 4 strata as measured from a series of young healthy individuals (H1 = highest; H2 = intermediate high; H3 = intermediate low; H4 = lowest anisotropy stratum).

RESULTS

For overall cerebral white matter, patients with AD had significantly lower FA than CN individuals or patients with MCI in the regions with higher baseline anisotropy (H1, H2, and H3), corresponding to long corticocortical association fibers, but not in H4, which mostly includes heterogeneously oriented fibers. Vascular risk showed significant independent effects on FA in all strata except H1, which corresponds to the genu and splenium of the corpus callosum. Similar results were found within NAWM. FA in WMH was significantly lower than NAWM across all strata but was not associated with diagnosis or vascular risk.

CONCLUSIONS

Both vascular and Alzheimer disease degenerative process contribute to microstructural injury of cerebral white matter across the spectrum of cognitive ability and have different region-specific injury patterns.

Isoflavonoid compounds extracted from Pueraria lobata suppress alcohol preference in a pharmacogenetic rat model of alcoholism

The extract from an edible vine, Pueraria lobata, has long been used in China to lessen alcohol intoxication. We have previously shown that daidzin, one of the major components from this plant extract, is efficacious in lowering blood alcohol levels and shortens sleep time induced by alcohol ingestion. This study was conducted to test the antidipsotropic effect of daidzin and two other major isoflavonoids, daidzein and puerarin, from Pueraria lobata administered by the oral route. An alcohol-preferring rat model, the selectively-bred P line of rats, was used for the study. All three isoflavonoid compounds were effective in suppressing voluntary alcohol consumption by the P rats. When given orally to P rats at a dose of 100 mg/kg/day, daidzein, daidzin, and puerarin decreased ethanol intake by 75%, 50%, and 40%, respectively. The decrease in alcohol consumption was accompanied by an increase in water intake, so that the total fluid volume consumed daily remained unchanged. The effects of these isoflavonoid compounds on alcohol and water intake were reversible. Suppression of alcohol consumption was evident after 1 day of administration and became maximal after 2 days. Similarly, alcohol preference returned to baseline levels 2 days after discontinuation of the isoflavonoids. Rats receiving the herbal extracts ate the same amounts of food as control animals, and they gained weight normally during the experiments. When administered orally, none of these compounds affected the activities of liver alcohol dehydrogenase and aldehyde dehydrogenase. Therefore, the reversal of alcohol preference produced by these compounds may be mediated via the CNS. Data demonstrate that isoflavonoid compounds extracted from Pueraria lobata is effective in suppressing the appetite for alcohol when taken orally, raising the possibility that other constituents of edible plants may exert similar and more potent actions.

Exposure to the BPA-Substitute Bisphenol S Causes Unique Alterations of Germline Function

Concerns about the safety of Bisphenol A, a chemical found in plastics, receipts, food packaging and more, have led to its replacement with substitutes now found in a multitude of consumer products. However, several popular BPA-free alternatives, such as Bisphenol S, share a high degree of structural similarity with BPA, suggesting that these substitutes may disrupt similar developmental and reproductive pathways. We compared the effects of BPA and BPS on germline and reproductive functions using the genetic model system Caenorhabditis elegans. We found that, similarly to BPA, BPS caused severe reproductive defects including germline apoptosis and embryonic lethality. However, meiotic recombination, targeted gene expression, whole transcriptome and ontology analyses as well as ToxCast data mining all indicate that these effects are partly achieved via mechanisms distinct from BPAs. These findings therefore raise new concerns about the safety of BPA alternatives and the risk associated with human exposure to mixtures.

Characterization of the affinities of insulin-like growth factor (IGF)-binding proteins 1-4 for IGF-I, IGF-II, IGF-I/insulin hybrid, and IGF-I analogs

Insulin-like growth factor (IGF)-binding proteins (BPs) bind IGF-I and IGF-II with high affinity and modify the activity of IGF peptides in a complex manner. We have characterized the affinities of IGFBP-1-4 for IGF-I and -II by employing 1) purified IGFBP preparations, 2) both [125I]IGF-I and [125I]IGF-II as radioligands, and 3) multiple IGF analogs designed to have altered affinities for IGFBPs. To this end, human (h) IGFBP-1, hIGFBP-2, and rat (r) IGFBP-4 have been purified to homogeneity from human amniotic fluid, human prostate epithelial cell culture, and B104 rat neuroblastoma cells; for human IGFBP-3, the glycosylated recombinant form (rec-hIGFBP-3), produced in Chinese hamster ovary cells, was employed. The IC50 values of IGF-I for hIGFBP-1, hIGFBP-2, rec-hIGFBP-3, rIGFBP-4, and human serum IGFBPs were 0.05 +/- 0.01, 5.0 +/- 0.01, 0.25 +/- 0.20, 0.6 +/- 0.4, and 0.1 +/- 0.01 ng/ml, respectively. While hIGFBP-1 and rIGFBP-4 had virtually equivalent affinities for IGF-I and IGF-II, hIGFBP-2 and rec-hIGFBP-3 demonstrated 2- to 5-fold higher affinities for IGF-II than for IGF-I. Studies with [Gln3,Ala4,Tyr15,Leu16]IGF-I and Des-(1-3)-IGF-I indicate that specific residues in the first 16 amino acids of the B domain of IGF-I appear to be critical for binding to all of the IGFBPs tested, but not to IGF receptors. However, severe modifications in the B domain disrupt binding affinity, not only for IGFBPs, but also for receptors (IGF-I/insulin hybrid and B-chain mutant). Interestingly, modifications in the A domain of IGF-I, which is believed to contain residues critical for binding to IGF-I and insulin receptors, show differential effects on binding affinity to BPs. [Thr49,Ser50,Ile51]IGF-I, which has normal affinity for the type I IGF receptor, shows at least a 500-fold decreased affinity for hIGFBP-1 and recombinant hIGFBP-3, in contrast to 50- to 100-fold reduced affinity for hIGFBP-2 and rIGFBP-4, and 5- to 10-fold reduced affinity for purified human serum IGFBP-3. More significantly, [1-27,Gly4,38-70]IGF-I shows a 30-fold decreased affinity for the type I IGF receptor and 10- and 2.5-fold reduced affinities for hIGFBP-1 and rec-hIGFBP-3, respectively, but no reduction in affinity for hIGFBP-2 or rIGFBP-4.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of the insulin-like growth factors (IGFs) and the IGF-binding proteins (IGFBPs) in human gastric cancer cells

Insulin-like growth factor (IGF)-I and -II are potent mitogens and postulated to exert autocrine, and paracrine effects on growth regulation in human gastric cancer. Their mitogenic effects are tightly regulated by the IGF binding proteins (IGFBPs). In this study, we evaluated the mRNA expression of IGF-I, IGF-II and the IGFBPs in a panel of human gastric cancer cell lines, and normal and tumour tissue specimens from patients with gastric cancer by reverse transcriptase-polymerase chain reaction (RT-PCR) and competitive PCR. Conditioned media (CM) of the gastric cancer cell lines were studied for the secretion of the IGFBPs by western ligand blot (WLB) and western immunoblot (WIB). IGF-I and IGF-II were expressed in all of the gastric cancer cell lines, and the normal and tumour tissue specimens. Overexpression of the IGFs, in particular, IGF-II, was observed in the tumour tissues. The expression pattern of IGFBPs was heterogeneous among the gastric cancer cell lines. IGFBP-2 was expressed in all of the gastric cancer cell lines, whereas IGFBP-1 was not detected in any cell lines. IGFBP-4 was expressed in the most of cell lines. IGFBP-3, IGFBP-5 and IGFBP-6 were expressed in approximately 50% of cell lines. In addition, exogenous IGF-I and IGF-II stimulated the proliferation of gastric cancer cells, suggesting the existence of a functional IGF system in gastric cancer. Taken together, our data-suggest that the IGF-IGFBP system may play an important role in the initiation, progression and metastasis of gastric cancer. Further studies are needed to understand the exact role of IGFs and IGFBPs in gastric neoplasia.

Mechanical properties, phase stability, and biocompatibility of (Y, Nb)-TZP/Al(2)O(3) composite abutments for dental implant

ZrO(2)/Al(2)O(3) composites were prepared by mixing a tetragonal ZrO(2), stabilized by 5.31 mol% Y(2)O(3) and 4.45 mol% Nb(2)O(5), and various amounts of Al(2)O(3). Influence of the amount of Al(2)O(3) on strength and toughness and tetragonal phase stability in the composites under autoclave conditions was investigated. In addition, in vitro and in vivo biocompatibility of the composites was examined. The composite, prepared with addition of 20 vol% Al(2)O(3), exhibited the highest strength of 700 MPa and toughness of 8.1 MPa. m(1/2) and showed no hydrothermal degradation while aging in an autoclave. The biocompatibility of the composite exhibited no cytotoxicity and no significant adverse soft-tissue response for up to 3 months implant period in guinea pigs.

Radiological response predicts survival following transarterial chemoembolisation in patients with unresectable hepatocellular carcinoma

BACKGROUND

It remains unclear whether initial compact lipiodol uptake after transarterial chemoembolisation (TACE) is associated with improved survival in patients with hepatocellular carcinoma (HCC).

AIM

To reveal the clinical relevance of compact lipiodolisation after TACE.

METHODS

We studied 490 patients with unresectable HCC who had first been treated with TACE. Compact lipiodolisation was defined as the absence of an arterial enhancing lesion, reflecting complete lipiodol uptake, as assessed by dynamic computed tomography (CT) 1 month after treatment. The rate of initial compact lipiodolisation was analysed according to multiplicity and size of tumour, and survival of patients who achieved compact lipiodolisation was compared to that of patients who did not.

RESULTS

Of the 490 patients, 409 (83.5%) were in Child-Pugh class A and 81 (16.5%) in class B. The rate of initial compact lipiodolisation in single HCCs was higher than that in multinodular HCCs (33.7% vs. 14.6%, P < 0.001). Among single HCCs, the rate of compact lipiodolisation in tumours ≤5, 5-10 and >10 cm was 46.6%, 13.6%, and 0% respectively. The 1-, 3- and 5-year survival rates of patients with compact uptake were 92.7%, 70.7% and 52.4% compared to 60.8%, 28.0% and 16.9% in patients with noncompact lipiodolisation. Multivariate analysis revealed that Child-Pugh class, alpha-fetoprotein level, tumour node metastasis stage, portal vein thrombosis and initial compact lipiodolisation were independent predictors of survival.

CONCLUSIONS

Initial compact lipiodol uptake after transarterial chemoembolisation is associated with improved survival in patients with unresectable hepatocellular carcinoma. Accordingly, initial complete lipiodolisation should be considered a relevant therapeutic target.

The dissected aorta: part I. Early anatomic changes in an in vitro model

PURPOSE

To define early anatomic changes in the aorta in an in vitro hydrostatic model of acute aortic dissection.

MATERIALS AND METHODS

Aortic dissections were created in explanted aortas. A small portion of the dissection flap was resected to allow free communication between the true and false lumina. The aortas were suspended in a saline bath and distended by means of a saline fluid column. By using intravascular ultrasonography, the arc lengths of the outer walls of the true and false lumina and of the dissection flap were measured at increasing hydrostatic pressures and at increasing fractions of dissected wall circumference.

RESULTS

The dissected aorta immediately became ectatic. At a given fraction of wall circumference involved in dissection, total aortic cross-sectional area increased with increased hydrostatic pressure. At a given hydrostatic pressure, this area increased with increased fraction of wall circumference dissected. Most of the increase was due to dilatation of the false lumen. There were minimal changes in true-lumen size. Dissection flap length, after initial contraction at the time of dissection, changed minimally with increasing pressure.

CONCLUSION

Anatomic changes in the dissected aorta depend on hydrostatic pressure and on the percentage of aortic wall involved in the dissection.

Osteoporotic Fracture: 2015 Position Statement of the Korean Society for Bone and Mineral Research

Osteoporotic fractures are one of the most common causes of disability and a major contributor to medical care costs worldwide. Prior osteoporotic fracture at any site is one of the strongest risk factors for a new fracture, which occurs very soon after the first fracture. Bone mineral density (BMD) scan, a conventional diagnostic tool for osteoporosis, has clear limitations in diagnosing osteoporotic fractures and identifying the risk of subsequent fractures. Therefore, early and accurate diagnosis of osteoporotic fractures using the clinical definition which is applicable practically and independent of BMD, is essential for preventing subsequent fractures and reducing the socioeconomic burden of these fractures. Fractures caused by low-level trauma equivalent to a fall from a standing height or less at major (hip, spine, distal radius, and proximal humerus) or minor (pelvis, sacrum, ribs, distal femur and humerus, and ankle) sites in adults over age 50, should be first regarded as osteoporotic. In addition, if osteoporotic fractures are strongly suspected on history and physical examination even though there are no positive findings on conventional X-rays, more advanced imaging techniques such as computed tomography, bone scan, and magnetic resonance imaging are necessary as soon as possible.

Elective endovascular treatment of descending thoracic aortic aneurysms and chronic dissections with stent-grafts

PURPOSE

To report our experience of endovascular stent-graft placement in patients with descending thoracic aortic dissections and aneurysms and to evaluate the feasibility, safety, and clinical outcomes of the treatment.

MATERIALS AND METHODS

Stent-grafts were placed in the descending thoracic aortas of 23 patients with saccular aneurysms (n = 11) and Stanford type B chronic aortic dissections of the descending thoracic and abdominal aorta (n = 12). All stent-grafts were individually constructed of self-expandable stainless steel stents covered with polytetrafluoroethylene. Vascular access was achieved through the femoral artery in all patients. Clinical status of each patient was monitored and postoperative CT was performed within 1 month of the procedure and at 3-12-month intervals after the procedures.

RESULTS

Successful exclusion of the primary entry tears of dissections and the inlets of saccular aneurysms was achieved in all but two patients with aortic dissection. The overall technical success rate was 91.3% (dissection: 10 of 12 = 83%; aneurysm: 11 of 11 = 100%). All patients in whom technical success was achieved showed complete thrombosis and significant decrease in diameter of the thoracic false lumen (preoperative: 5.3 cm +/- 0.9; postoperative: 4.3 cm +/- 0.9; P = .004) or aneurysm sac (preoperative: 5.3 cm +/- 1.7; postoperative: 2.8 cm +/- 2.5; P = .001). In addition, five patients demonstrated complete resolution of the dissected thoracic false lumen (n = 2) and aneurysm sac (n = 3). However, in all patients with aortic dissection, the abdominal aorta was not significantly changed in size (P = .302) and shape and their false lumen flows remained persistent. Immediate postoperative complications were detected in 12 patients (52%); 10 had fever, leukocytosis, and elevation of C-reactive protein, another had wound infection, and another had transient abdominal pain. Three patients died 2, 3, and 12 months after the procedure: one from septic shock, another from underlying mediastinitis, and the other from an unexplained cause. The remaining 20 patients were well after the procedure (1-9 days; mean, 3 days), without any stent-graft-related complications or discomfort (follow up period: 10-65 mo; mean: 25.1 mo +/- 15.6). The cumulative survival rate after the stent graft was 100% at 30 days and 91% at 12 months.

CONCLUSIONS

For treatment of aortic dissection and saccular aneurysm of the descending thoracic aorta, endovascular stent-graft repair may be a technically feasible and effective treatment modality.

RNase mitochondrial RNA processing correctly cleaves a novel R loop at the mitochondrial DNA leading-strand origin of replication

The precursor primer RNA for mammalian mitochondrial DNA leading-strand replication remains as a persistent R loop formed during transcription through the mitochondrial DNA control region. We have examined model R loops, which exist in a novel and physiologically accurate preprimer conformation, as potential substrates for mammalian RNase mitochondrial RNA processing (MRP). Mouse RNase MRP accurately cleaves an R loop containing the mouse mitochondrial DNA origin. The multiple cleavage sites on the R-loop substrate match the priming sites observed in vivo, suggesting that RNase MRP alone is capable of generating virtually all of the leading-strand replication primers.