A nearby long gamma-ray burst from a merger of compact objects.

Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive stars1, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars2. A third class of events with hybrid high-energy properties was identified3, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions4-6, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented7,8. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 1042 erg per second) kilonova possibly formed in the ejecta of a compact object merger.

Altered Rheological Properties of Saliva with Aging in Mouse Sublingual Gland.

Mucin in saliva plays a critical role in the hydration and lubrication of the oral mucosa by retaining water molecules, and its impaired function may be associated with hyposalivation-independent xerostomia. Age-dependent effects on salivary gland function and rheological properties of secreted saliva are not fully understood as aging is a complex and multifactorial process. We aimed to evaluate age-related changes in the rheological properties of saliva and elucidate the underlying mechanism. We performed ex vivo submandibular gland (SMG) and sublingual gland (SLG) perfusion experiments to collect saliva from isolated glands of young (12 wk old) and aged (27 mo old) female C57BL/6J mice and investigate the rheological properties by determining the spinnbarkeit (viscoelasticity). While fluid secretion was comparable in SMG and SLG of both mice, spinnbarkeit showed a significant decrease in SLG saliva of aged mice than that of young mice. There were no significant differences in GalNAc concentration between young and aged SLG saliva. Liquid chromatography/tandem mass spectrometry analysis of SLG saliva revealed that (Hex)1 (HexNAc)1 (NeuAc)1 at m/z 793.31 was the most abundant O-glycan structure in SLG saliva commonly detected in both mice. Lectin staining of salivary gland tissue showed that SLG stained strongly with Maackia amurensis lectin II (MAL II) while Sambucus nigra agglutinin (SNA) stained little, if any, SLG. The messenger RNA expression of St3gal1 that encodes an α-2,3 sialic acid sialyltransferase SIAT4-A showed a decrease in SLG of aged mice, confirmed by a Western blot analysis. Lectin blot analysis in SLG saliva revealed that the relative signal intensity detected by MAL II was significantly lower in aged SLG. Our results suggest that spinnbarkeit decreases in SLG of aging mice due to downregulation of sialic acid linked to α-2,3 sialic acid sialyltransferase expression.

Printable PICN Composite Mechanically Compatible with Human Teeth.

Polymer-infiltrated ceramic network (PICN) composites are mechanically compatible with human enamel, and are therefore promising dental restorative materials. Fabrication technology for PICN composites used in tooth restorative material has been established through computer-aided design/computer-aided manufacturing (CAD/CAM) milling, however, to date, has not been successfully developed using 3-dimensional (3D) printing. This study aimed to develop a 3D-printable PICN composite as a restorative material. The PICN composite was fabricated using a specific method based on 3D printing. A 3D-printable precursor slurry containing a high concentration of silica nanoparticles was produced and 3D-printed using stereolithography (SLA). The 3D-printed object was sintered to obtain a nano-porous object, and subsequently infiltrated and polymerized with resin monomer. Three different fabrication condition combinations were used to produce the 3D-printed PICN composites, which were characterized based on microstructure, mechanical properties, inorganic content, physicochemical properties, and overall shrinkage. The 3D-printed PICN composites were also compared to 2 commercially available CAD/CAM composite blocks, namely a PICN composite and a dispersed-filler composite. The 3D-printed PICN composites exhibited a nano-sized dual-network structure comprising a silica skeleton with infiltrated resin. The 3D-printed PICN composite exhibited a similar Vickers hardness to enamel, and a similar elastic modulus to dentin. The 3D-printed PICN composite exhibited comparable flexural strength (>100 MPa) to the CAD/CAM block, and acceptable water sorption and solubility for practical use. Further, the 3D-printed model-crown underwent isotropic shrinkage during sintering without fatal deformation. Overall, the potential of this 3D-printable PICN composite as a restorative material with similar mechanical properties to human teeth was successfully demonstrated.

Endothelin-1 Elicits TRP-Mediated Pain in an Acid-Induced Oral Ulcer Model.

Oral ulcer is the most common oral disease and leads to pain during meals and speaking, reducing the quality of life of patients. Recent evidence using animal models suggests that oral ulcers induce cyclooxygenase-dependent spontaneous pain and cyclooxygenase-independent mechanical allodynia. Endothelin-1 is upregulated in oral mucosal inflammation, although it has not been shown to induce pain in oral ulcers. In the present study, we investigated the involvement of endothelin-1 signaling with oral ulcer-induced pain using our proprietary assay system in conscious rats. Endothelin-1 was significantly upregulated in oral ulcers experimentally induced by topical acetic acid treatment, while endothelin-1 production was suppressed by antibacterial pretreatment. Spontaneous nociceptive behavior in oral ulcer model rats was inhibited by swab applications of BQ-788 (ETB receptor antagonist), ONO-8711 (prostanoid receptor EP1 antagonist), and HC-030031 (TRPA1 antagonist). Prostaglandin E2 production in the ulcers was suppressed by BQ-788. Mechanical allodynia in the model was inhibited not only by BQ-788 and HC-030031 but also by BQ-123 (ETA receptor antagonist), SB-366791 (TRPV1 antagonist), and RN-1734 (TRPV4 antagonist). In naive rats, submucosal injection of endothelin-1 caused mechanical allodynia that was sensitive to HC-030031 and SB-366791 but not to RN-1734. These results suggest that endothelin-1 production following oral bacterial invasion via ulcerative regions elicits TRPA1-mediated spontaneous pain. This pain likely occurs through an indirect route that involves ETB receptor-accelerated prostanoid production. Endothelin-1 elicits directly TRPA1- and TRPV1-mediated mechanical allodynia via both ETA and ETB receptors on nociceptive fibers. The TRPV4-mediated allodynia component seems to be independent of endothelin signaling. These findings highlight the potential of endothelin signaling blockers as effective analgesic approaches for oral ulcer patients.

Bone Aging by Advanced Glycation End Products: A Multiscale Mechanical Analysis.

The quality and quantity of mandibular bone are essential prerequisites for osseointegrated implants. Only the Hounsfield unit on preoperative computed tomography is currently used as a clinical index. Nevertheless, a considerable mismatch occurs between bone quality and the Hounsfield unit. Loss of bone toughness during aging has been accepted based on empirical evidence, but this concept is unlikely evidence based at the level of mechanical properties. Nonenzymatic bone matrix cross-links associated with advanced glycation end products predominate as a consequence of aging. Thus, loss of tissue integrity could diminish the bone toughening mechanism. Here, we demonstrate an impaired bone toughening mechanism caused by mimicking aging in rabbits on a methionine-rich diet, which enabled an enhanced nonenzymatically cross-linked bone matrix. A 3-point bending test revealed a greater reduction in femoral fracture resistance in rabbits on a methionine-rich diet, despite higher maximum and normalized breaking forces (287.3 N and 88.1%, respectively), than in rabbits on a normal diet (262.2 N and 79.7%, respectively). In situ nanoindentation on mandibular cortical bone obtained from rabbits on a methionine-rich diet did not enable strain rate-dependent stiffening and consequent large-dimensional recovery during rapid loading following constant displacement after a rapid-load indentation test as compared with those in rabbits on a normal diet. Such nanoscale structure-function relationships dictate resistance to cracking propagation at the material level and allow for the overall bone toughening mechanism to operate under large external stressors. The strain-dependent stiffening was likely associated with strain-energy transfer to the superior cross-linked bone matrix network of the normal diet, while the reduction in the enzymatically cross-linked matrix in bone samples from rabbits on a methionine-rich diet likely diminished the intrinsic bone toughening mechanism. The present study also provides a precise protocol for evaluating bone mechanical properties at the material level based on observations from a series of nanoindentation experiments.

Produção e comercialização do guaco (Mikania laevigata Schultz Bip. ex Baker) na região Sul do Estado do Paraná / Production and commercialization of guaco (Mikania laevigata Schultz Bip. ex Baker) in the south of Paraná State

Resumo O Estado do Paraná destaca-se pela tradição no cultivo de plantas medicinais. O aumento em sua demanda através da busca de culturas alternativas e rentáveis e o estímulo a uma agricultura ecologicamente sustentável fomentou os agricultores a diversificarem a produção. A pesquisa de campo nos diferentes elos da cadeia produtiva do guaco permitiu construir seu fluxograma, caracterizar o sistema e fluxo de produção, os seus custos e receitas para analisar as Margens e Markups de comercialização. Os sistemas de coleta com enriquecimento e de cultivo apresentaram resultados diferenciados em relação ao seu custo de produção, onde o produtor/coletor alcança uma rentabilidade de 48,9 %, menor margem de comercialização entre todos os elos da cadeia, enquanto o produtor que cultiva o guaco como exploração obtém uma margem de comercialização de 346,4 %. As maiores margens de comercialização (1.733,3 %) estão nos elos fora da porteira das propriedades, percentual entre diferença de preço pago pelo consumidor e o preço recebido pelo produtor/coletor. Os produtores/coletores podem agregar mais renda em vários elos da cadeia produtiva através da organização dos produtores e a melhoria no processo produtivo, possibilitando a melhoria econômica e social nas propriedades familiares, reduzindo o impacto ambiental e garantindo a sustentabilidade dos sistemas de produção.

Abstract The State of Parana stands out for its tradition in the medicinal plants cultivation. The increase of the demand due to the search of alternative and profitable crops and the impulse to an environmentally sustainable agriculture encouraged farmers to diversify production. The field research about the different links of the guaco supply chain allowed the construction of its flowchart, the characterization of the production system and flow, as well as the knowledge of its costs and revenues in order to analyze the commercialization margins and markups. The collection systems with enrichment and the cultivation ones presented different results in relation to its production cost, with the producer/collector reaching a yield of 48.9%, the lowest commercialization margin among all links of the chain, while the farmer who cultivates guaco gets a commercialization margin of 346.4%. The largest commercialization margins (1,733.3%) are in the links outside the properties" gates, as the percentage difference between the price paid by the consumer and the one received by the producer/collector. Producers/collectors can add more income in several links of the supply chain through the producers" organization and by improvements in the production process, enabling the economic and social enhancement at the family farms, thus reducing the environmental impact and ensuring the sustainability of production systems.

Management of sleep-time masticatory muscle activity using stabilisation splints affects psychological stress.

To treat sleep bruxism (SB), symptomatic therapy using stabilisation splints (SS) is frequently used. However, their effects on psychological stress and sleep quality have not yet been examined fully. The objective of this study was to clarify the effects of SS use on psychological stress and sleep quality. The subjects (11 men, 12 women) were healthy volunteers. A crossover design was used. Sleep measurements were performed for three consecutive days or longer without (baseline) or with an SS or palatal splint (PS), and data for the final day were evaluated. We measured masseter muscle activity during sleep using portable electromyography to evaluate SB. Furthermore, to compare psychological stress before and after sleep, assessments were made based on STAI-JYZ and the measurement of salivary chromogranin A. To compare each parameter among the three groups (baseline, SS and PS), Friedman's and Dunn's tests were used. From the results of the baseline measurements, eight subjects were identified as high group and 15 as low group. Among the high group, a marked decrease in the number of bruxism events per hour and an increase in the difference in the total STAI Y-1 scores were observed in the SS group compared with those at baseline (P < 0·05). No significant difference was observed in sleep stages. SS use may be effective in reducing the number of SB events, while it may increase psychological stress levels, and SS use did not apparently influence sleep stages.

Distinct effects of cevimeline and pilocarpine on salivary mechanisms, cardiovascular response and thirst sensation in rats.

OBJECTIVE: Cevimeline and pilocarpine (muscarinic receptor agonists) are used as sialogogues in xerostomia treatment. It is important to know the different effects on their salivary mechanisms and the side effects. The aim of the present study was to clarify and compare the comprehensive effects of cevimeline to pilocarpine on salivary, cardiovascular and central mechanisms in rats. DESIGN: Under anaesthesia, whole saliva secretion, parotid blood flow and blood pressure were measured following intra-peritoneal administrations of the sialogogues. In digested parotid cells, intracellular Ca(2+) concentrations were measured after the sialogogue application. In the conscious condition, changes in angiotensin II-induced water intake were observed after cevimeline administration. In the subfornical organ, which is a thirst-related central nucleus, the effect of cevimeline on the neuronal activity was electrophysiologically investigated. RESULTS: Cevimeline at 80µmolkg(-1) showed slowly increasing and lasting salivation, a similar blood flow increment in the parotid gland and higher pressor response when compared to pilocarpine at 4µmolkg(-1). In parotid cells, cevimeline increased the intracellular Ca(2+) concentration in a similar manner to pilocarpine, but at a higher concentration than pilocarpine. Cevimeline inhibited angiotensin II-induced water intake and neuronal activity in the subfornical organ, which is in contrast to reported effects of pilocarpine. CONCLUSIONS: Cevimeline activates common salivary mechanism with pilocarpine but has a slower onset of activation, longer duration of salivation and an increased pressor response at higher doses. The anti-dipsogenic effect of cevimeline is due to the inhibitory neuronal effect on the thirst-related central nuclei.

DNA amplification using phi29 DNA polymerase validates gene polymorphism analysis from buccal mucosa samples.

Venous blood is currently the most common source of DNA for gene polymorphism screening; however, blood sampling is invasive and difficult to perform in general dental treatment. Buccal mucosa samples provide an alternative source of DNA, but it is frequently difficult to effectively amplify the DNA owing to the small amounts of sample material obtained. This study was performed to establish a method for performing total genomic DNA amplification from buccal mucosa samples using phi29 DNA polymerase. Total genomic DNA was isolated from buccal mucosa samples obtained from healthy subjects and was amplified using phi29 DNA polymerase. To determine the suitability of the extracted DNA for genotyping, polymerase chain reaction and restriction fragment length polymorphism analyses were performed for the IL-1 gene polymorphism. Genotyping of the IL-1 polymorphism was successful using the amplified DNA from a buccal mucosa, but genotyping was unsuccessful using the unamplified control because of low DNA purity. The method of extracting DNA from a buccal mucosa is painless, simple, minimally invasive, and rapid. Genomic DNA from a buccal mucosa can be amplified by phi29 DNA polymerase in sufficient quantity and quality to conduct gene polymorphism analyses.

Diagnostic accuracy of cardiac metaiodobenzylguanidine scintigraphy in Parkinson disease.

BACKGROUND AND PURPOSE: To estimate the diagnostic accuracy of cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigram for detection of Parkinson disease. METHODS: A cross-sectional study with index test of MIBG scintigram and reference standard of U.K. Parkinson's Disease Brain Bank Criteria was performed in 403 patients. Ratio of cardiac-to-mediastinum MIBG accumulation was determined at 20 min (early H/M) and 4 h (late H/M). Area under the receiver-operator characteristic (ROC) curve, sensitivity and specificity in detecting Parkinson disease were analyzed. Accuracy was analyzed in a subgroup of patients with disease duration of 3 years or less. RESULTS: Area under the ROC curve was 0.89 using either early or late H/M as a diagnostic marker (95% CI 0.85-0.92 for early H/M and 0.86-0.93 for late H/M). Sensitivity and specificity were 81.3% (76.1-85.8%) and 85.0% (77.7-90.6%) for early H/M and 84.3% (79.3-88.4%) and 89.5% (83.01-94.1%) for late H/M. In the subgroup with duration of 3 years or less, the ROC curve area, sensitivity, and specificity were 0.86 (0.79-0.92), 76.0% (64.8-85.1%), and 83.9% (71.7-92.4%) for early H/M and 0.85 (0.78-0.92), 73.3% (61.9-82.9%), and 87.5% (75.9-94.8%) for late H/M. CONCLUSION: Although diagnostic accuracy of cardiac MIBG scintigram is high, it is limited because of insufficient sensitivity in patients with short duration.

Epithelial fibroblast growth factor receptor 1 regulates enamel formation.

The interaction between epithelial and mesenchymal tissues plays a critical role in the development of organs such as teeth, lungs, and hair. During tooth development, fibroblast growth factor (FGF) signaling is critical for regulating reciprocal epithelial and mesenchymal interactions. FGF signaling requires FGF ligands and their receptors (FGFRs). In this study, we investigated the role of epithelial FGF signaling in tooth development, using the Cre-loxp system to create tissue-specific inactivation of Fgfr1 in mice. In K14-Cre;Fgfr1(fl/fl) mice, the apical sides of enamel-secreting ameloblasts failed to adhere properly to each other, although ameloblast differentiation was unaffected at early stages. Prior to eruption, enamel structure was compromised in the K14-Cre;Fgfr1(fl/fl) mice and displayed severe enamel defects that mimic amelogenesis imperfecta (AI), with a rough, irregular enamel surface. These results suggest that there is a cell-autonomous requirement for FGF signaling in the dental epithelium during enamel formation. Loss of Fgfr1 affects ameloblast organization at the enamel-secretory stage and, hence, the formation of enamel.

TGF-beta 3 decreases type I collagen and scarring after labioplasty.

Cleft lip is a common congenital malformation, and labioplasty performed on infants to repair such defects often results in severe scar formation. Since TGF-beta 3 has been implicated in wound healing, we therefore hypothesized that TGF-beta 3 functions to reduce scarring after cleft lip repair. In this investigation, we demonstrated that exogenous TGF-beta 3 reduced scar formation in an incised and sutured mouse lip in vivo. During labioplasty, endogenous TGF-beta 3 expression was also elevated. In vitro experiments showed that exogenous TGF-beta 3 reduced type I collagen accumulation. Furthermore, TGF-beta 3 inhibited alpha-smooth-muscle actin expression, a marker for myofibroblasts. In tandem, TGF-beta 3 induced the expression and activity of MMP-9. Analysis of our data suggests that TGF-beta 3 is normally secreted following labioplastic wound healing. An elevated level of TGF-beta 3 reduces type I collagen deposition by restricting myofibroblast differentiation and thereby collagen synthesis, and by promoting collagen degradation by MMP-9. In combination, these events lead to TGF-beta 3-mediated reduced scar formation.

TGF-beta-3 promotes scarless repair of cleft lip in mouse fetuses.

TGF-beta3 mediates epithelial-mesenchymal transformation during normal fusion of lip and palate, but how TGF-beta3 functions during cleft lip repair remains unexplored. We hypothesize that TGF-beta3 promotes fetal cleft lip repair and fusion by increasing the availability of mesenchymal cells. In this investigation, we demonstrated that cleft lips in mouse fetuses were repaired by fetal surgery, producing scarless fusion. At the site of the operation, we first observed an infusion of platelets expressing TGF-beta3, followed by increased expression of cyclin D1 and tenascin-C, and coupled with increased mesenchymal cell proliferation. In an ex vivo serumless culture system, cleft lip explants fused in the presence of exogenous TGF-beta3. Cultured lips also showed up-regulation in cyclin D1 and tenascin-C expression. These findings suggest that microsurgical repair of cleft lip in the fetus that produced scarless fusion is mediated by TGF-beta3 regulation of mesenchymal cell proliferation and migration at the site of repair.

Plasma leptin levels and cardiac sympathetic function in patients with obstructive sleep apnoea-hypopnoea syndrome.

BACKGROUND: The control of body weight and cardiac sympathetic function in patients with obstructive sleep apnoea-hypopnoea syndrome (OSAHS) are important because both factors have significant effects on the mortality of these patients. It has recently been reported that OSAHS has a significant effect on the secretion of leptin, a hormone involved in the control of body weight and sympathetic nerve activity. In addition to the circadian rhythm of leptin secretion, the effects of one night of treatment with nasal continuous positive airway pressure (nCPAP) and the mechanism of the effects of nCPAP on nocturnal leptin secretion in patients with OSAHS has not yet been elucidated. METHODS: Blood samples were obtained at 21.00 hours, 00.00 hours, 03.00 hours, and 06.30 hours from 21 subjects with OSAHS (mean apnoea and hypopnoea index 52.4/h), with and without nCPAP treatment. Iodine-123 (I(123))-meta-iodobenzylguanidine (MIBG) imaging was used to evaluate myocardial sympathetic function before nCPAP treatment. RESULTS: Plasma leptin reached a peak level at 00:00 hours (p<0.01) in patients with OSAHS, both with and without nCPAP treatment. The first night of nCPAP treatment significantly decreased the plasma leptin levels at 03.00 hours (without nCPAP: mean (SE) 21.6 (4.7) ng/ml; with nCPAP: 19.3 (4.1) ng/ml, p<0.02) and at 06.30 hours (without nCPAP: 17.6 (3.8) ng/ml; with nCPAP: 15.2 (3.2) ng/ml, p<0.01). The magnitude of the decrease in leptin levels after nCPAP treatment was significantly correlated with cardiac sympathetic function measured before nCPAP treatment (p<0.03). CONCLUSIONS: Patients with OSAHS undergo nocturnal increases in leptin levels in spite of interruption of sleep due to apnoea and hypopnoea, a trend seen in normal subjects. Plasma leptin levels in patients with OSAHS decreased significantly after the first night of nCPAP treatment. Enhanced cardiac sympathetic function in these patients may contribute to the leptin levels before nCPAP treatment and vice versa.

Myocardial metabolism of 123I-BMIPP during low-flow ischaemia in an experimental model: comparison with myocardial blood flow and 18F-FDG.

Risk stratification of coronary artery disease may provide a basis for selection of treatment to prevent myocardial events and to assist functional recovery. Iodine-123 (rho-iodophenyl)-3-R,S-methylpentadecanoic acid (123I-BMIPP) is a radioiodinated fatty acid analogue for single-photon emission tomographic (SPET) imaging, and several reports have demonstrated that the abnormal uptake of 123I-BMIPP is associated with wall motion abnormality and severe coronary artery stenosis. Clarification of the contribution of fatty acids to myocardial metabolism would be highly valuable in recognising this critical condition. In this study, we investigated the myocardial uptake of 123I-BMIPP under low-flow ischaemia, and compared it with the uptake of fluorine-18 fluorodeoxyglucose (18F-FDG). Using open chest dogs, the flow of the left anterior descending coronary artery was controlled using a pneumatic occluder in order to maintain a 30%-40% reduction of Doppler flow. 123I-BMIPP and 18F-FDG were injected into the left atrium after 90 min of ischaemia (protocols 1 and 3). Canine hearts were excised after 120 min of ischaemia for the measurement of radioactivity. In protocol 2, 123I-BMIPP alone was injected and hearts were excised 8 min after the injection. A time-course biopsy study was also performed at the same time (protocol 3). Wall thickening was evaluated using a wall tracker module. The uptake of 18F-FDG increased significantly in the ischaemic region (232%+/-135% vs non-ischaemic, P<0.05 in protocol 1) even on mild reduction of myocardial blood flow (MBF). The increased uptake of 18F-FDG did not correlate well with the severity of MBF. On the other hand, 123I-BMIPP uptake decreased gradually (78.9%+/-23.6%, P<0.05 in protocol 1, and 85.9%+/-24.3% in protocol 2) in the ischaemic region, specifically in the endocardium (64.0%+/-28.9%, P<0.05 in protocol 1, and 75.1%+/-28.8%, P<0.05 in protocol 2), and correlated strongly with MBF (r=0.93 in protocol 1 and r=0.97 in protocol 2) as a logarithmic function. This indicated that the abnormal uptake of 123I-BMIPP was associated not only with wall motion abnormality but also with the severity of MBF. In the biopsy study (protocol 3), the radioactivity of either 123I-BMIPP or 18F-FDG correlated well with the MBF at the time of tracer injection and was similar to post-mortem analysis. It is concluded that 18F-FDG is a valid tool for identifying ischaemic myocardium even in its earliest stages. On the other hand, 123I-BMIPP might be used to detect moderately to severely ischaemic myocardium such as hibernation, suggesting the potential value of 123I-BMIPP in the risk stratification of patients with severe coronary artery disease who require revascularisation without delay.

The effects of buccolingual width and position of occlusal rest seats on load transmission to the abutments for tooth-supported removable partial dentures.

PURPOSE: The suitable buccolingual width and the location of occlusal rest seats for removable partial dentures have not been scientifically established. The aim of the present study was to use three-dimensional geometric analysis to evaluate the effects of buccolingual width and the location of occlusal rest seats on load transmission to the abutments for tooth-supported removable partial dentures. MATERIALS AND METHODS: A tooth-supported portion of a maxillary removable partial denture with two conventional circumferential cast clasps and an indirect retainer was analyzed. Occlusal loading of 100 N was applied to the buccal mesial cuspal incline 2.0 mm from the central fossa of the first molar or to the lingual mesial cuspal tip. Four combinations of position and width (wide, buccal shift, middle, and lingual shift) were simulated. RESULTS: For buccal loading, the wide rests and buccal-shift rests produced lower tensile forces at the indirect retainer. For lingual loading, the buccal-shift rests produced the lowest compressive force to the anterior abutment. CONCLUSION: Based on the tooth-supported removable partial dentures that were analyzed, buccal shifting of the rest seats seems to be advantageous for load transmission to the abutments.

Enhanced external counterpulsation improved myocardial perfusion and coronary flow reserve in patients with chronic stable angina; evaluation by(13)N-ammonia positron emission tomography.

AIMS: The mechanism by which enhanced external counterpulsation therapy exerts its beneficial effects on chronic and symptomatic stable angina is largely unknown. To clarify the mechanism of action of enhanced external counterpulsation, we used(13)N-ammonia positron emission tomography to evaluate myocardial perfusion. METHODS AND RESULTS: This was not a randomized controlled study. Eleven patients (eight male, age: 61.6+/-9.7) with angina pectoris underwent enhanced external counterpulsation therapy for 35 1 h sessions. They underwent a treadmill exercise test and(13)N-ammonia positron emission tomography, both at rest and with dipyridamole, before and after enhanced external counterpulsation therapy. Neurohumoral factors and nitric oxide were also evaluated. Myocardial perfusion increased at rest after therapy (0.69+/-0.27 to 0.85+/-0.47 ml x min(-1) x g(-1), P<0.05). In ischaemic regions, particularly the anterior region, myocardial perfusion at rest and with dipyridamole and coronary flow reserve improved significantly after therapy (at rest: 0.71+/-0.26 to 0.86+/-0.31;P<0.05, with dipyridamole: 1.26+/-0.65 to 1.84+/-0.94;P<0.02, coronary flow reserve: 1.75+/-0.24 to 2.08+/-0.28;P<0.04). Exercise time was prolonged and the time to 1-mm ST depression improved markedly (P<0.01). After therapy, nitric oxide levels increased (P<0.02) and neurohumoral factors decreased. CONCLUSIONS: Enhanced external counterpulsation therapy improved myocardial perfusion at rest and with dipyridamole and was associated with an increased exercise tolerance with(13)N-ammonia positron emission tomography and increased nitric oxide levels. These results suggest that one of the enhanced external counterpulsation mechanisms is development and recruitment of collateral vessels.

Extremely high drug-reductase activity based on aldehyde oxidase in monkey liver.

Drug-reducing ability of monkey liver cytosol was examined in this study. Monkey liver cytosol exhibited significant reductase activities toward zonisamide, sulindac and imipramine N-oxide in the presence of 2-hydroxypyrimidine or benzaldehyde, an electron donor to aldehyde oxidase. These activities were abolished by inhibitors of aldehyde oxidase, such as menadione. These reductase activities in monkeys were extremely high compared to those in other animals. The zonisamide reductase activity of monkey liver cytosol was about 40-fold higher than that of the liver microsomes. It appears that the high levels of aldehyde oxidase exists in monkey liver, and zonisamide, sulindac and imipramine N-oxide are mainly reduced by this enzyme, not by cytochrome P450.

Effect of abutment tooth reinforcement techniques on the fracture resistance of removable partial denture master casts.

PURPOSE: The purpose of this study was to compare the mean loads required to fracture an isolated stone abutment tooth when various reinforcement techniques were used: (A) no reinforcement, (B) surface hardening, (C) impression trimming, (D) dowel placement, and (E) impression trimming plus dowel placement. MATERIALS AND METHODS: Die stone premolar specimens for each group (n = 4) were loaded perpendicular to the tooth long axis in 100-g increments 25 hours after pouring the impression. Mean load to failure was determined for each group. Data were evaluated with a one-way analysis of variance (alpha = 0.05) to determine differences among groups. Paired comparisons of factor level means were made with Tukey's q-test. RESULTS: The mean fracture load for Group E (7.6 kg) was significantly greater than Groups A (2.0 kg), B (2.1 kg), and C (3.4 kg). No significant difference was found between Groups D (6.0 kg) and E. CONCLUSIONS: Dowel reinforcement with impression trimming at the cervical portion of the abutment tooth resulted in significantly greater fracture resistance than the control, surface model hardener, or impression trimming alone. J Prosthodont 2001;10:22-25.