Pharmacokinetic study of BSH and BPA in simultaneous use for BNCT

In order to improve the effectiveness of boron neutron capture therapy (BNCT) for malignant gliomas, we examined the optimization of the administration of boron compounds in brain tumor animal model. We analyzed the concentration of boron atoms in intracranial C6 glioma -bearing rats using inductively coupled plasma atomic emission spectrometry. Each tumor-bearing rat received one of two different amounts of sodium borocaptate (BSH) and/or 500 mg/kg of boronophenylalanine (BPA) via intraperitoneal injection. We compared the boron concentrations of the tumor, the contralateral normal brain and the blood in rats of 3 different treatment groups (BSH alone, BPA alone and a combination of both BSH and BPA). Our results show that the tumor boron concentration increased much more than 30 microg/g by the coadministration of both compounds. Additionally, the blood boron concentration remained below 30 microg/g and the boron concentration in the normal brain was low (mean 4.7+/-1.1 microg/g). Even in comparison with the administration of BPA alone, coadministration of BPA and BSH shows an improved tumor/normal brain ratio of boron concentrations.

Long-term outcome after primary stenting versus balloon angioplasty for acute myocardial infarction

The objective of the present prospective multicenter case-control study was to investigate the long-term clinical outcome (5 years) of primary stenting compared to primary percutaneous transluminal coronary angioplasty (PTCA) without stenting (POBA) in patients with acute myocardial infarction at 7 cardiovascular centers in Hokkaido, Japan. Forty-one patients with acute myocardial infarction treated with successful primary stenting (stent group: case) and paired with 41 matched control subjects with acute myocardial infarction treated by successful primary PTCA without stenting (POBA group: control) were analyzed. After 1 year, the stent group had a lower incidence of the combined clinical endpoint (death, rehospitalization due to congestive heart failure, nonfatal myocardial infarction, repeat angioplasty, CABG, or cerebrovascular events) compared to the POBA group (17.1% versus 39.0%, P = 0.049). After 5 years, the incidences of congestive heart failure and cardiac death were the same in both groups. However, compared to the POBA group, the stent group had a lower combined clinical endpoint (34.1% versus 61.0%, P = 0.027). The Kaplan-Meier event-free survival curves of the stent group showed a significantly lower occurrence of clinical events compared to the POBA group (P = 0.0116). Multiple logistic regression analysis of clinical events identified age > or = 69 years (P = 0.0092, odds ratio = 4.179) and stenting (P = 0.0158, odds ratio = 0.279) as explanatory factors. Compared with POBA, primary stenting for acute myocardial infarction results in a better long-term clinical outcome.

Genomic data assimilation for estimating hybrid functional Petri net from time-course gene expression data

We propose an automatic construction method of the hybrid functional Petri net as a simulation model of biological pathways. The problems we consider are how we choose the values of parameters and how we set the network structure. Usually, we tune these unknown factors empirically so that the simulation results are consistent with biological knowledge. Obviously, this approach has the limitation in the size of network of interest. To extend the capability of the simulation model, we propose the use of data assimilation approach that was originally established in the field of geophysical simulation science. We provide genomic data assimilation framework that establishes a link between our simulation model and observed data like microarray gene expression data by using a nonlinear state space model. A key idea of our genomic data assimilation is that the unknown parameters in simulation model are converted as the parameter of the state space model and the estimates are obtained as the maximum a posteriori estimators. In the parameter estimation process, the simulation model is used to generate the system model in the state space model. Such a formulation enables us to handle both the model construction and the parameter tuning within a framework of the Bayesian statistical inferences. In particular, the Bayesian approach provides us a way of controlling overfitting during the parameter estimations that is essential for constructing a reliable biological pathway. We demonstrate the effectiveness of our approach using synthetic data. As a result, parameter estimation using genomic data assimilation works very well and the network structure is suitably selected.

A combined pathway to simulate CDK-dependent phosphorylation and ARF-dependent stabilization for p53 transcriptional activity

The protein p53 is phosphorylated by a member of protein kinases such as CDK7, and stabilized by the protein ARF. The phosphorylation and stabilization of p53 is believed to enhance its transcriptional activity and act simultaneously. Biological pathways composed of experts knowledge obtained from the literature are including these activation mechanisms. However, the map of biological pathways does not reflect the combination effect of phosphorylation and stabilization. We have conducted some simulations of biological pathways with hybrid functional Petri net (HFPN) after careful reading of papers. In this paper, we constructed the HFPN based biological pathway of CDK-dependent phosphorylation pathway and combine with ARF-dependent pathway described previously, to observe the effect of the phosphorylation on the stabilization with simulation-based validation.

Simulation-based validation of the p53 transcriptional activity with hybrid functional petri net

MDM2 and p19ARF are essential proteins in cancer pathways forming a complex with protein p53 to control the transcriptional activity of protein p53. It is confirmed that protein p53 loses its transcriptional activity by forming the functional dimer with protein MDM2. However, it is still unclear that protein p53 keeps its transcriptional activity when it forms the trimer with proteins MDM2 and p19ARF. We have observed mutual behaviors among genes p53, MDM2, p19ARF and their products on a computational model with hybrid functional Petri net (HFPN) which is constructed based on information described in the literature. The simulation results suggested that protein p53 should have the transcriptional activity in the forms of the trimer of proteins p53, MDM2, and p19ARE This paper also discusses the advantages of HFPN based modeling method in terms of pathway description for simulations.

A statistical framework for genome-wide discovery of biomarker splice variations with GeneChip Human Exon 1.0 ST Arrays

Alternative splicing is an important regulatory mechanism that generates multiple mRNA transcripts which are transcribed into functionally diverse proteins. According to the current studies, aberrant transcripts due to splicing mutations are known to cause for 15% of genetic diseases. Therefore understanding regulatory mechanism of alternative splicing is essential for identifying potential biomarkers for several types of human diseases. Most recently, advent of GeneChip Human Exon 1.0 ST Array enables us to measure genome-wide expression profiles of over one million exons. With this new microarray platform, analysis of functional gene expressions could be extended to detect not only differentially expressed genes, but also a set of specific-splicing events that are differentially observed between one or more experimental conditions, e.g. tumor or normal control cells. In this study, we address the statistical problems to identify differentially observed splicing variations from exon expression profiles. The proposed method is organized according to the following process: (1) Data preprocessing for removing systematic biases from the probe intensities. (2) Whole transcript analysis with the analysis of variance (ANOVA) to identify a set of loci that cause the alternative splicing-related to a certain disease. We test the proposed statistical approach on exon expression profiles of colorectal carcinoma. The applicability is verified and discussed in relation to the existing biological knowledge. This paper intends to highlight the potential role of statistical analysis of all exon microarray data. Our work is an important first step toward development of more advanced statistical technology. Supplementary information and materials are available from http://bonsai.ims.u-tokyo.ac.jp/~yoshidar/IBSB2006_ExonArray.htm.

Preferential Recurrence of a Sarcomatous Component of a Gliosarcoma after Boron Neutron Capture Therapy: Case Report

Gliosarcoma, a rare pathological entity composed of 2-8% malignant gliomas, is characterized by a biphasic tissue pattern with alternating areas displaying glial and mesenchymal differentiation. Here we report the preferential recurrence of a sarcomatous component in gliosarcoma after boron neutron capture therapy (BNCT), while a gliomatous component disappeared as a result of the treatment. A 56-year-old woman with a left frontal tumor was introduced to our clinic. After stereotactic biopsy, craniotomy was applied and 90% of the mass was resected. The histological diagnosis was glioblastoma with small amounts of sarcomatous component, that is, gliosarcoma. BNCT was applied 30 days after craniotomy. Two weeks after BNCT, almost all of the contrast-enhanced mass had disappeared on magnetic resonance images; however, a half year later, the mass recurred just below the original site and extended posteriorly. Irrespective of repetitive salvage surgeries, the patient died of the recurrent tumor. At autopsy, tumor cells of the frontal lobe were absent. A well-circumscribed mass of the parietal and occipital lobes was composed of sarcomatous material, with very little glial fibrillary acid protein-positive glial material. We found in this patient the preferential recurrence of the sarcomatous component of a gliosarcoma after potent radiotherapeutics in the form of BNCT.

Doppler-Free Two-Photon Excitation Spectroscopy and the Zeeman Effects. Perturbations in the and Bands of the S1 ← S0 Transition of C6D6

Doppler-free two-photon excitation spectra and the Zeeman effects for the 1 band of the S1 1B2u <-- S0 1A1g transition in gaseous benzene-d6 were measured. Although the spectral lines were strongly perturbed, almost all of the lines near the band origin could be assigned. From a deperturbation analysis, the perturbation near the band origin was identified as originating from an anharmonic resonance interaction. Perturbation centered at K = 28-29 in the 14(0)1 band was analyzed, and it was identified as originating from a perpendicular Coriolis interaction. The symmetry and the assignment of the perturbing state proposed by Schubert et al. (Schubert, U.; Riedle, E.; Neusser, H. J. J. Chem. Phys. 1989, 90, 5994.) were confirmed. No perturbation originating from an interaction with a triplet state was observed in both bands. From the Zeeman spectra and the analysis, it is demonstrated that rotationally resolved levels are not mixed with a triplet state. The intersystem mixing is not likely to occur at levels of low excess energy in the S1 state of an isolated benzene. Nonradiative decay of an isolated benzene in the low vibronic levels of the S1 state will occur through the internal mixing followed by the rotational and vibrational relaxation in the S0 state.

Acute Hemodynamic Benefits of Bi-Atrial Atrioventricular Sequential Pacing With the Optimal Atrioventricular Delay

OBJECTIVES

We evaluate the acute effects on hemodynamics of bi-atrial (BiA) pacing with the optimal atrioventricular (AV) delays, in comparison with high right atrial (HRA) pacing and coronary sinus (CS) pacing.

BACKGROUND

Bi-atrial pacing has been suggested as one of the alternative therapy for preventing the recurrence of atrial fibrillation (AF). There are, however, few reports on the hemodynamic effects of BiA pacing, and the results that exist are controversial.

METHODS

Twenty patients were paced from HRA, left lateral site of CS, and both sites with the optimal AV delays at 80 and 100 beats/min, in random order. After 5-min pacing, maximal P-wave duration in a 12-lead electrocardiogram, cardiac output (CO), pulmonary capillary wedge pressure (PCWP), and the transmitral flow pattern by transthoracic echocardiography were measured.

RESULTS

Compared with HRA and CS pacing, BiA pacing delivered the shortest P-wave duration (HRA: 130 +/- 14 ms, CS: 132 +/- 19 ms, and BiA: 94 +/- 8 ms, respectively, p < 0.001) and the most improvement in CO and PCWP (HRA: 3.63 +/- 0.67 l/min and 9.2 +/- 4.3 mm Hg, CS: 3.71 +/- 0.70 l/min and 8.8 +/- 3.4 mmHg, and BiA: 3.88 +/- 0.63 l/min and 8.0 +/- 3.1 mmHg, respectively, p < 0.01). Bi-atrial pacing also significantly increased the mitral flow time velocity integral and peak A-wave velocity by transthoracic echocardiography, compared with HRA and CS pacing (HRA: 7.6 +/- 1.4 cm and 68.8 +/- 12.2 cm/s, CS: 7.8 +/- 1.4 cm and 70.5 +/- 14.5 cm/s, and BiA: 8.2 +/- 1.2 cm and 76.3 +/- 14.2 cm/s, respectively, p < 0.01). Bi-atrial pacing most significantly decreased the intervals between the atrial pacing spike and the peak of A-wave (HRA: 180 +/- 28 ms, CS: 165 +/- 21 ms, and BiA: 157 +/- 19 ms, respectively, p < 0.01). These improvements in hemodynamics significantly correlated with interatrial conduction delay.

CONCLUSIONS

Bi-atrial pacing made the most significant improvements of hemodynamics. These benefits may be due to the improvements in interatrial conduction delay and atrial dyssynchrony.

Acute improvement of atrial mechanical stunning after electrical cardioversion of persistent atrial fibrillation: comparison between biatrial and single atrial pacing

OBJECTIVE

To evaluate the acute effects of atrial pacing at different pacing sites on mechanical stunning after cardioversion of atrial fibrillation (AF).

SETTING

Tertiary referral centre.

PATIENTS

20 patients with persistent AF were studied.

INTERVENTIONS

Spontaneous echo contrast (SEC), left atrial appendage emptying velocity (LAAEV), and left atrial appendage emptying fraction (LAAEF) were assessed by transoesophageal echocardiography (TOE) during AF, after conversion to sinus rhythm, and during atrial pacing from the right atrial appendage, left lateral atrium, and both atria simultaneously. Transmitral inflow velocity of the atrial wave (TMIF-A) by TOE and the maximum P wave duration in 12 lead ECG were also measured during sinus rhythm and atrial pacing.

MAIN OUTCOME MEASURES

Comparison of atrial mechanical function and P wave duration in 12 lead ECG during atrial pacing from different sites after cardioversion of AF.

RESULTS

Compared with sinus rhythm, atrial pacing at 80 beats/min increased LAAEV from mean (SD) 14.6 (10.1) to 33.4 (19.8) cm/s (p = 0.001), LAAEF from 13.8 (8.5) to 32.1 (11.2)% (p < 0.001), and TMIF-A from 24.6 (11.9) to 45.6 (21.0) cm/s (p < 0.001) and reduced SEC grade from 2.6 (1.0) to 1.6 (0.9) (p < 0.001). These effects had a positive force-frequency relation. Biatrial pacing produced the shortest P wave duration and resulted in the most significant improvement in atrial function (LAAEV, 33.2 (19.3) v 53.7 (23.9) cm/s, p = 0.0001; LAAEF, 31.9 (11.1) v 46.2 (12.6)%, p < 0.0001; TMIF-A, 37.7 (18.3) v 54.1 (21.2) cm/s, p < 0.001; SEC grade, 1.4 (1.1) v 0.8 (0.9), p = 0.001, right atrial appendage versus biatrial pacing).

CONCLUSIONS

Atrial pacing at increased rates can improve atrial mechanical function after cardioversion of persistent AF. Biatrial pacing may be the most effective technique to reverse atrial mechanical stunning.

Automatic drawing of biological networks using cross cost and subcomponent data

Automatic graph drawing function for biopathways is indispensable for biopathway databases and softwares. This paper proposes a new grid-based algorithm for biopathway layout that considers (a) edge-edge crossing, (b) node-edge crossing, (c) distance measures between nodes, as its costs, and (d) subcellular localization information from Gene Ontology, as its constraints. For this algorithm, we newly define cost functions, devise an efficient method for computing the costs (a)-(c) by employing a matrix representing the difference between two layouts, and take a steepest descent method for searching locally optimal solutions and multi-step layout method for finding better solutions. We implemented this algorithm on Cell Illustrator which is a biopathway modeling and simulation software. The algorithm is applied to a signal transduction pathway of apoptosis induced by fas ligand. We compare our layout with that of the grid-based algorithm by Li and Kurata (Bioinformatics 21 (9):2036-2042, 2005). The result shows that our algorithm reduces edge-edge crossings and node-edge crossings, and solves the ''isolated island problem'', that is, despite the intension, some groups of nodes are apart from other nodes in the layout. As a result, the biological understandability of the layout is fairly improved.

In vivo and in vitro Patch-clamp Recording Analysis of the Process of Sensory Transmission in the Spinal Cord and Sensory Cortex

Following the integration and modification of the sensory inputs in the spinal cord, the information is transmitted to the primary sensory cortex where the integrated information is further processed and perceived. Processing of the sensory information in the spinal cord has been intensively investigated. However, the mechanisms of how the inputs are processed in the cortex are still unclear. To know the correlation of the sensory processing in the dorsal horn and cortex, in vivo and in vitro patch-clamp recordings were made from rat dorsal horn and sensory cortex. Although dorsal horn neurons showed spontaneous and evoked EPSCs by noxious and non-noxious stimuli, most somatosensory neurons located at 100 to 1000 microm from the surface of the cortex exhibited an oscillatory activity and received synaptic inputs from non-noxious but not noxious receptors. These observations suggest that the synaptic responses in cortical neurons are processed in a more complex manner; and this may be due to the reciprocal synaptic connection between thalamus and cortex.

[Traumatic internal carotid artery dissection due to compression by a helmet strap]

It is well known that wearing a helmet can reduce the risk of head injury in a traffic accident. We report a case of traumatic cervical internal carotid artery dissection due to compression by the strap of a helmet after a motorcycle accident. A 21 year-old man fell off his motorcycle and his head was struck at the right parietal region. His helmet prevented head injury, but the helmet strap which was fixed around his neck compressed his cervical internal carotid artery. He lost consciousness and developed left hemiparesis two hours after being admitted to an emergency department. Cerebral angiography revealed dissection of he right cervical internal carotid artery. This lesion was treated successfully by stent placement two months after the accident. The cause of carotid dissection was thought to be compression of his neck by the helmet strap. If the strap of a helmet is fixed around the neck, it can cause carotid artery injury during an accident, so it can be concluded that the strap of a helmet should be fixed firmly at the chin.

Biopathways representation and simulation on hybrid functional Petri net

The following two matters should be resolved in order for biosimulation tools to be accepted by users in biology/medicine: (1) remove issues which are irrelevant to biological importance, and (2) allow users to represent biopathways intuitively and understand/manage easily the details of representation and simulation mechanism. From these criteria, we firstly define a novel notion of Petri net called Hybrid Functional Petri Net (HFPN). Then, we introduce a software tool, Genomic Object Net, for representing and simulating biopathways, which we have developed by employing the architecture of HFPN. In order to show the usefulness of Genomic Object Net for representing and simulating biopathways, we show two HFPN representations of gene regulation mechanisms of Drosophila melanogaster (fruit fly) circadian rhythm and apoptosis induced by Fas ligand. The simulation results of these biopathways are also correlated with biological observations. The software is available to academic users from http://www.GenomicObject.Net/.

Application of in vivo patch-clamp technique to pharmacological analysis of synaptic transmission in the CNS

Slice preparations as well as acutely dissociated and cultured neurons from various regions in the CNS have been widely used to analyze pharmacological properties of synaptic responses and receptors expressed at the pre- and post-synaptic sites. However, the essential properties are not obviously different from neuron to neuron. These characteristics of neurons in the CNS make it difficult to elucidate their functional significances. It is, therefore, preferable that the pharmacological analysis should be made from identified neurons by stimulation of identified inputs. The in vivo patch-clamp recording technique allows us to clarify the synaptic responses evoked by the various known natural stimuli applied to the skin or other parts and makes it possible to interpret with more certainty the behavioral changes by synaptic plasticity observed at the single cell level. Although the in vivo technique has obvious advantages in analysis of physiological responses, this method is, however, confined so far to neurons located at the near surface of the CNS for pharmacological analysis, because of the diffusion problem of the chemical to deeper neurons. Thus, combinatorial studies with dissociated or cultured neurons or with slice preparations are clearly required for further understanding of pharmacological properties of neurons in the CNS.

Prognostic value of fatty acid imaging in patients with angina pectoris without prior myocardial infarction: comparison with stress thallium imaging

A fatty acid analogue, 123I-labelled beta-methyl iodophenyl pentadecanoic acid (BMIPP), has been used to identify ischaemic and metabolically impaired myocardium. However, the prognostic value of BMIPP imaging, particularly in relation to stress myocardial perfusion imaging, remains unclear. Data from 167 consecutive patients with angina pectoris but without prior myocardial infarction (MI) who had undergone both BMIPP and stress 201Tl (sTL) imaging were analysed. Tracer uptake was graded using a 13-segment, 4-point scoring model. Patients were followed up for 48 months with primary end points (cardiac death, non-fatal MI) as hard cardiac events and with secondary end points (late revascularisation, recurrent angina and heart failure) as soft events. For overall cardiac events (5 hard and 29 soft events), Kaplan-Meier analysis revealed significantly lower event rates in subgroups with normal BMIPP uptake, a summed difference score of sTL (SDS) of <3 or absence of diabetes mellitus when compared to each counterpart. Multivariate Cox's analysis revealed reduced BMIPP uptake, SDS > or =3, diabetes and reduced ejection fraction to be significant predictors. Negative predictive values of normal BMIPP and SDS <3 for all events were 91% and 84%, respectively. No hard event occurred in 66 patients with normal BMIPP uptake, whereas two patients with SDS <3 but impaired BMIPP uptake had hard events. In conclusion, normal BMIPP imaging is an excellent prognostic sign, independently of stress myocardial perfusion imaging, in patients with angina pectoris without prior MI.

Acute haemodynamic benefits of biatrial atrioventricular sequential pacing: comparison with single atrial atrioventricular sequential pacing

OBJECTIVE

To evaluate the acute effects on haemodynamic variables of biatrial pacing in comparison with high right atrial (HRA) pacing and left lateral atrial pacing.

PATIENTS AND DESIGN

23 patients were paced from the HRA site, the lateral site of the coronary sinus (CS), and both sites on two fixed atrioventricular delays (100 and 150 ms) during atrioventricular sequential pacing at 80 and 100 beats/min in random order.

MAIN OUTCOME MEASURES

After five minute pacing, the maximum P wave duration on a 12 lead ECG, cardiac output, pulmonary capillary wedge pressure, and the transmitral flow pattern by transthoracic echocardiography were measured.

RESULTS

Biatrial pacing delivered the shortest P wave duration (133 (25) ms, 133 (27) ms, and 96 (15) ms during HRA, CS, and biatrial pacing, respectively; p < 0.001), and the most improvement in cardiac output and pulmonary capillary wedge pressure (3.71 (0.93) l/min and 15 (7) mm Hg, 3.79 (0.97) l/min, and 14 (6) mm Hg, and 4.09 (1.01) l/min and 13(6) mm Hg during HRA, CS, and biatrial pacing, respectively; p < 0.01). Biatrial pacing most significantly decreased the intervals between the atrial pacing spike and the peak and end of the atrial filling wave (186 (16) ms and 250 (22) ms, 172 (19) ms and 242 (24) ms, and 153 (15) ms and 227 (23) ms during HRA, CS, and biatrial pacing, respectively; p < 0.001). It also significantly increased the mitral flow time velocity integral and peak atrial filling wave velocity (7.5 (3.4) cm and 63.8 (17.6) cm/s, 7.8 (3.0) cm and 62.4 (16.6) cm/s, and 8.3 (3.4) cm and 67.8 (19.3) cm/s during HRA, CS, and biatrial pacing, respectively; p < 0.05). The improvements in haemodynamic variables were especially remarkable in patients who had a longer interatrial conduction delay.

CONCLUSIONS

Biatrial pacing yielded the most significant improvements in haemodynamic variables. These haemodynamic benefits may play a part in reducing intra-atrial pressure and preventing atrial fibrillation.

Sub-Doppler rotationally resolved spectroscopy of lower vibronic bands of benzene with Zeeman effects

Sub-Doppler high-resolution excitation spectra and the Zeeman effects of the 6(0)(1), 1(0)(1)6(0)(1), and 1(0)(2)6(0)(1) bands of the S1(1)B2u<--S(0)(1)A1g transition of benzene were measured by crossing laser beam perpendicular to a collimated molecular beam. 1593 rotational lines of the 1(0) (1)6(0) (1) band and 928 lines of the 1(0)(2)6(0)(1) band were assigned, and the molecular constants of the excited states were determined. Energy shifts were observed for the S1(1)B2u(v1=1,v6=1,J,Kl=-11) levels, and those were identified as originating from a perpendicular Coriolis interaction. Many energy shifts were observed for the S1(1)B2u(v1=2,v6=1,J,Kl) levels. The Zeeman splitting of a given J level was observed to increase with K and reach the maximum at K=J, which demonstrates that the magnetic moment lies perpendicular to the molecular plane. The Zeeman splittings of the K=J levels were observed to increase linearly with J. From the analysis, the magnetic moment is shown to be originating mostly from mixing of the S1(1)B2u and S2(1)B1u states by the J-L coupling (electronic Coriolis interaction). The number of perturbations was observed to increase as the excess energy increases, and all the perturbing levels were found to be a singlet state from the Zeeman spectra.

Thymic Carcinoma Presenting as Cranial Metastasis with Intradural and Extracranial Extension: Case Report

OBJECTIVE AND IMPORTANCE

Thymic carcinoma is an uncommon malignant tumor that is different from thymoma. Cranial and brain metastases from this tumor are extremely rare. We report a thymic carcinoma with cranial metastasis and discuss the behavior of this tumor.

CLINICAL PRESENTATION

A 50-year-old man presented with headache and a palpable scalp tumor. Computed tomographic scans and magnetic resonance images revealed an osteolytic tumor with intradural and extracranial extension in the right occipital bone.

INTERVENTION

After gross total resection and histological diagnosis, further investigation revealed a primary thymic tumor in the anterior upper mediastinum and liver metastases. The patient received multiple-cycle chemotherapy (cisplatin and gemcitabine) for primary and metastatic lesions.

CONCLUSION

Thymic carcinoma has a poor prognosis because of a high degree of malignancy, early metastasis, and delayed diagnosis. Thus, treatment of a patient with this tumor calls for prompt diagnosis, surgical treatment, and optimal adjuvant therapy.

A versatile petri net based architecture for modeling and simulation of complex biological processes

The research on modeling and simulation of complex biological systems is getting more important in Systems Biology. In this respect, we have developed Hybrid Function Petri net (HFPN) that was newly developed from existing Petri net because of their intuitive graphical representation and their capabilities for mathematical analyses. However, in the process of modeling metabolic, gene regulatory or signal transduction pathways with the architecture, we have realized three extensions of HFPN, (i) an entity should be extended to contain more than one value, (ii) an entity should be extended to handle other primitive types, e.g. boolean, string, (iii) an entity should be extended to handle more advanced type called object that consists of variables and methods, are necessary for modeling biological systems with Petri net based architecture. To deal with it, we define a new enhanced Petri net called hybrid functional Petri net with extension (HFPNe). To demonstrate the effectiveness of the enhancements, we model and simulate with HFPNe four biological processes that are diffcult to represent with the previous architecture HFPN.

Constructing biological pathway models with hybrid functional Petri nets

In many research projects on modeling and analyzing biological pathways, the Petri net has been recognized as a promising method for representing biological pathways. From the pioneering works by Reddy et al., 1993, and Hofestädt, 1994, that model metabolic pathways by traditional Petri net, several enhanced Petri nets such as colored Petri net, stochastic Petri net, and hybrid Petri net have been used for modeling biological phenomena. Recently, Matsuno et al., 2003b, introduced the hybrid functional Petri net (HFPN) in order to give a more intuitive and natural modeling method for biological pathways than these existing Petri nets. Although the paper demonstrates the effectiveness of HFPN with two examples of gene regulation mechanism for circadian rhythms and apoptosis signaling pathway, there has been no detailed explanation about the method of HFPN construction for these examples. The purpose of this paper is to describe method to construct biological pathways with the HFPN step-by-step. The method is demonstrated by the well-known glycolytic pathway controlled by the lac operon gene regulatory mechanism.

Actions of noradrenaline on substantia gelatinosa neurones in the rat spinal cord revealed by in vivo patch recording

To elucidate the mechanisms of antinociception mediated by the descending noradrenergic pathway in the spinal cord, the effects of noradrenaline (NA) on noxious synaptic responses of substantia gelatinosa (SG) neurones, and postsynaptic actions of NA were investigated in rats using an in vivo whole-cell patch-clamp technique. Under urethane anaesthesia, the rat was fixed in a stereotaxic apparatus after the lumbar spinal cord was exposed. In the current-clamp mode, pinch stimuli applied to the ipsilateral hindlimb elicited a barrage of EPSPs, some of which initiated an action potential. Perfusion with NA onto the surface of the spinal cord hyperpolarized the membrane (5.0-9.5 mV) and suppressed the action potentials. In the voltage-clamp mode (V(H), -70 mV), the application of NA produced an outward current that was blocked by Cs(+) and GDP-beta-S added to the pipette solution and reduced the amplitude of EPSCs evoked by noxious stimuli. Under the blockade of postsynaptic actions of NA, a reduction of the evoked and spontaneous EPSCs of SG neurones was still observed, thus suggesting both pre- and postsynaptic actions of NA. The NA-induced outward currents showed a clear dose dependency (EC(50), 20 microM), and the reversal potential was -88 mV. The outward current was mimicked by an alpha(2)-adrenoceptor agonist, clonidine, and suppressed by an alpha(2)-adrenoceptor antagonist, yohimbine, but not by alpha(1)- and beta-antagonists. These findings suggest that NA acts on presynaptic sites to reduce noxious stimuli-induced EPSCs, and on postsynaptic SG neurones to induce an outward current by G-protein-mediated activation of K(+) channels through alpha(2)-adrenoceptors, thereby producing an antinociceptive effect.

Real time quantification of low temperature radiofrequency ablation lesion size using phased array intracardiac echocardiography in the canine model: comparison of two dimensional images with pathological lesion characteristics

OBJECTIVE

To evaluate the feasibility of quantifying low temperature radiofrequency catheter ablation (RFCA) lesions using a phased array intracardiac echocardiography (ICE) catheter--with better tissue penetration and in a deflectable device-in the canine model.

INTERVENTION

Low temperature radiofrequency (RF) energy (50-60 degrees C at up to 40 W) was delivered to the left ventricle in 11 beagles for 60 seconds, using an 8 French catheter with a deflectable tip and a 4 mm distal electrode.

MAIN OUTCOME MEASURES

Comparison of the width and depth of RFCA lesions measured by ICE with pathological findings.

RESULTS

33 RF energies were delivered in 11 dogs. 31 lesions (94%) were confirmed at necropsy. 27 of 31 ablation lesions (87%) were detected by ICE. The mean (SD) width and depth of the ICE detected lesions were 10.4 (2.6) mm and 5.7 (1.9) mm, respectively. Pathological findings showed that RFCA lesions consisted of inner and outer layers. Macroscopically, the mean (SD) width and depth of the inner layers were 7.6 (2.3) mm and 3.6 (1.2) mm and those for the whole layers were 10.0 (2.8) mm and 5.3 (1.5) mm, respectively. Microscopically, the inner and outer layers corresponded to necrotic and oedematous areas, respectively. The ICE detected lesion size had better correlation with the pathological measurements of the whole layers in width (r = 0.911) and in depth (r = 0.756).

CONCLUSION

The real time evaluation of RFCA lesion size using the phased array ICE is feasible, even with a low temperature RF application. However, ICE slightly overestimates RFCA lesion size compared with pathological necrotic lesion size.

An unusual case of primary effusion lymphoma in a HIV-negative patient not pathogenetically associated with HHV8

The development of an unusual case of primary pleural effusion in a 90-year-old human immunodeficiency virus (HIV)-negative Japanese woman with no identifiable tumor mass has been described. Pleural effusion specimens contained large diffuse lymphoma cells, with the phenotype and genotype of a B-cell lineage (positive for CD20, CD79a and clonal rearrangement of Ig heavy chain) and the c-myc gene rearrangement, but were negative for T-cell markers (CD45RO and CD3). The patient was negative for human herpes virus 8 (HHV8), Epstein-Barr virus (EBV) and hepatitis C virus (HCV), as well as human T-cell lymphotropic virus type-1 (HTLV-1). The patient died of respiratory failure 5 months after the diagnosis of primary effusion lymphoma (PEL), and an autopsy was performed. Autopsy findings revealed no evidence of tumor mass or bone marrow involvement of lymphoma cells. This case has been considered as a PEL in a HIV-, HHV8-, EBV- and HCV-negative patient. Although cytomorphology of lymphoma cells was classified as large-cell lymphoma in this case, it is interesting that the present case may represent an unusual subset of Burkitt-like disease because of clear B-cell phenotype and c-myc gene rearrangement.

Genomic Object Net: I. A platform for modelling and simulating biopathways

Genomic Object Net (GON) 1.0 is a software package for creating models and simulations of biopathways. Its core architecture employs the notion of a hybrid functional Petri net with extension (HFPNe). HFPNe can seamlessly handle discrete and continuous objects and events while keeping the model components themselves simple. With the feature and graphical model editor, biopathways can be modelled intuitively and simulated on GON. The subsequent output of the simulation results can be evaluated in customised views on GON Visualizer by writing an XML file. Additionally, GON provides a tool to transform biopathway models in KEGG and BioCyc to the GON XML files for modelling and simulation. The tool avoids a lot of tedious work by users, enabling them to focus on the biological model.

Genomic Object Net: II. Modelling biopathways by hybrid functional Petri net with extension

This paper demonstrates how to create an HFPNe (hybrid functional Petri net with extension) model, using the lac operon gene regulatory mechanism and glycolytic pathway as an example. Using this example, readers can then model other biopathways of interest. Simulations of the HFPNe model were performed using the software package Genomic Object Net.

Acetazolamide vasoreactivity evaluated by transcranial harmonic perfusion imaging: relationship with transcranial Doppler sonography and dynamic CT

To establish the reliability and clinical significance of transcranial ultrasonic harmonic perfusion imaging (HPI), we evaluated HPI's relationships with transcranial Doppler (TCD) and with dynamic CT (DCT), during acetazolamide (ACZ) vasoreactivity tests.

METHODS

The subjects were 12 neurological patients. Time-averaged maximum velocity (TAVMX) in the middle (MCA) and posterior cerebral arteries was measured by TCD. Time-intensity (-density) curves of HPI (DCT) after bolus intravenous contrast injections were created in 3 regions of interest (ROI) on the axial plane involving the temporal lobe, basal ganglia, and thalamus on both sides. Assessments of vasoreactivity were based on comparisons conducted before and after ACZ administration in terms of: a) relative changes (%delta) of the TCD TAVMX, b) HPI contrast area enlargement, c) %delta of calculated cerebral blood volume and flow of the HPI and DCT.

RESULTS

1) TCD vasoreactivity decrease in the left MCA tended to correlate with lower frequency of HPI contrast area enlargement on the left side. 2) HPI and DCT vasoreactivity tended to be disturbed in the same side ROIs.

CONCLUSIONS

Transcranial HPI achieves repeatable non-invasive bedside evaluation of cerebrovascular reserve capacity through qualitative and quantitative measurements of brain tissue perfusion, and will have clinical value in pathophysiological follow-up and therapeutic effectiveness determination of neurointensive care patients.

Diagnostic implications of modified treadmill and head-up tilt tests in exercise-related syncope: comparative studies with situational and/or vasovagal syncope

BACKGROUND

The precise pathophysiological basis of exercise-related vasodepressor syncope is not well understood.

PURPOSE

The diagnostic values of head-up tilt and modified treadmill tests with abrupt termination were tested in patients with exercise-related syncope and compared with those of patients with situational or vasovagal syncope.

PATIENTS AND METHODS

Diagnostic accuracies of head-up tilt and modified treadmill exercise tests were examined in 44 patients with unexplained syncope (26 men, 18 women, aged 46 19 years) and in 20 control subjects. Results for 18 patients with syncope during exercise (short-distance dash [n=7], jogging [n=3], going up stairs [n=6], swimming [n=1] or cycling [n=1]), defined as exercise-related syncope, were compared with those for 26 patients with exercise-unrelated syncope (including situational [n=7] and vasovagal [n=14] syncope).

RESULTS

No differences were found between the clinical backgrounds of subjects with and those without exercise-related syncope. Head-up tilt testing had good diagnostic sensitivities, specificities and accuracies in both exercise-related and exercise-unrelated groups (84% versus 77%, 84% versus 85%, 84% versus 80%, respectively). The corresponding values of modified treadmill tests in the two groups were 78% versus 19% (P<0.05), 95% versus 95% and 86% versus 52% (P<0.05), respectively. The results of exercise tests were of limited diagnostic value for exercise-unrelated syncope. Beta-blockade had good short term efficacy in subjects with exercise-related syncope (nine of 15, 60%) as well as in subjects with exercise-unrelated syncope (seven of 10, 70%).

CONCLUSIONS

Modified treadmill exercise testing is thought to be useful for diagnosing exercise-related syncope.

XML documentation of biopathways and their simulations in Genomic Object Net

Genomic Object Net is a software tool for modeling and simulating biopathways which employs the notion of hybrid functional net as its basic architechture. This paper shows how to integrate this basic architecture with XML documents for biopathway representations, simulations, and visualizations for creating a tailor-made simulation environment.

Presynaptic inhibition of GABAergic miniature currents by metabotropic glutamate receptor in the rat CNS

The modulation of spontaneous miniature GABAergic inhibitory postsynaptic currents (mIPSC) by the metabotropic glutamate receptors was investigated in the mechanically dissociated rat nucleus basalis of Meynert neurons using the conventional whole-cell patch recording configuration. An application of (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (tACPD) reversibly reduced the frequency of mIPSC without affecting the current amplitude distribution. The application of K+ channel blockers such as 4-aminopyridine, Cs+, Ba2+ or tetraethylammonium increased the mIPSC frequency, but failed to inhibit the tACPD action on mIPSC. Although the removal of Ca2+ from the extracellular solution reduced the mIPSC frequency, the inhibitory effect of tACPD on mIPSC was unaltered. These results suggested that neither voltage-dependent K+ or Ca2+ channels are involved in the inhibitory effect of tACPD on mIPSC frequency. Forskolin, an activator of adenylate cyclase, facilitated the mIPSC frequency in a concentration-dependent manner and inhibited the tACPD-induced suppression of mIPSC frequency. 8-Br-cAMP, a membrane permeable analog of cAMP, also prevented the inhibitory action of tACPD. However, Sp-cAMP, an activator of protein kinase A, could not prevent the inhibitory action of tACPD. L-CCG-I and (2R,4R)-APDC, group II mGluR agonists, mimicked the tACPD action on mIPSC frequency, but L-AP4, a group III mGluR agonist, had no such effect. MCCG, a group II mGluR antagonist, fully blocked the tACPD action. It was concluded that the activation of group II mGluR on the GABAergic presynaptic nerve terminals projecting to the rat nucleus basalis of Meynert neurons therefore inhibits the GABA release by reducing the activity of the cAMP-dependent pathway.

Na(+)/Ca(2+) exchanger in GABAergic presynaptic boutons of rat central neurons

Rat Meynert neurons were acutely isolated using a dissociation technique that maintains functional GABAergic presynaptic boutons. Miniature inhibitory postsynaptic currents (mIPSCs) were recorded under voltage-clamp conditions using whole cell patch-clamp recordings. Using the frequency of mIPSCs as a measure of presynaptic terminal excitability, the existence of a Na(+)/Ca(2+) exchanger (NCX) in these GABAergic nerve terminals was clearly demonstrated. Both the frequency and the amplitude of mIPSCs were unaffected by replacement of extracellular Na(2+). However, in this Na(+)-free external solution, ouabain could now induce a transient increase of mIPSCs frequency, which was not inhibited by adding Cd(2+) or cyclopiazonic acid but was inhibited by removing external Ca(2+). This indicates that this transient potentiation was dependent on external Ca(2+), but that this Ca(2+) influx was not via voltage-dependent Ca(2+) channels. KB-R7943, an inhibitor of NCX, at a concentration of 3 x 10(-6) M, reduced this transient increase of mIPSCs frequency without affecting mIPSCs amplitude and the response to exogenous GABA. These results demonstrate the existence of NCX in these GABAergic nerve terminals. In zero external Na(+), ouabain causes an accumulation of intraterminal Na(+) and a resultant influx of Ca(2+) through the reversed mode operation of NCX. However, under more physiological conditions, NCX may also operate in a forward mode and serve to maintain low intracellular [Ca(2+)] in nerve terminals.

An electrophysiological study of muscarinic and nicotinic receptors of rat paratracheal ganglion neurons and their inhibition by Z-338

1. To study the mechanisms involved in the action of Z-338, a newly synthesized gastroprokinetic agent, experiments were performed with the paratracheal ganglion cells acutely dissociated from 2-week-old Wistar rats. The effects of Z-338 on both nicotinic and muscarinic responses of the ganglion cells were studied by nystatin perforated patch recording configuration under the current- and voltage-clamp conditions. 2. Acetylcholine (ACh) or nicotine, and muscarine or oxotremorine-M (OX-M) induced membrane depolarization with rapid and slow time courses respectively, followed by repetitive generation of action potentials in the ganglion cell. Corresponding to the membrane depolarization induced by cholinergic agents, ACh induced biphasic inward currents with rapid and slow time courses under the voltage-clamp condition. Nicotine and muscarine or OX-M evoked inward currents with rapid and slow time courses, respectively. The rapid and slow inward currents were accompanied by increase and decrease in the membrane conductance, respectively. In addition, OX-M dose-dependently suppressed the M-type K(+) current evoked in response to hyperpolarizing voltage-steps from V(H) of -25 mV to -50 mV, indicating that the activation of muscarinic acetylcholine receptors inhibits M-type K(+) current, thus inducing inward current in the ganglion cell. 3. Z-338 competitively suppressed the inward currents induced by OX-M through M(1) ACh receptor, and uncompetitively suppressed the currents induced by nicotine. 4. The inhibitory actions of Z-338 on the membrane depolarization and corresponding inward currents mediated by M(1)-muscarinic and neuronal nicotinic ACh receptors in the isolated ganglion cells were discussed in relation to the inhibitory actions on autoreceptors in the parasympathetic nerve terminals, which would explain the gastroprokinetic actions of Z-338.

Aconitine facilitates spontaneous transmitter release at rat ventromedial hypothalamic neurons

The effects of aconitine, an Aconitum alkaloid, on spontaneous inhibitory and excitatory postsynaptic currents (IPSCs and EPSCs respectively) were investigated in the mechanically dissociated rat ventromedial hypothalamic (VMH) neurons in which native presynaptic nerve terminals remained intact. Under current-clamp conditions, aconitine (3 x 10(-6) M) depolarized the neuron with generating the action potentials. The aconitine-induced depolarization was markedly suppressed in the presence of CNQX but it was facilitated in the presence of bicuculline, suggesting that release of excitatory and inhibitory neurotransmitters may be involved in the aconitine action in addition to its direct action on postsynaptic membrane. Under the voltage-clamp conditions, aconitine reversibly increased the frequency of spontaneous IPSC and EPSC frequency, but it did not alter their amplitude distribution. Tetrodotoxin (TTX, 3 x 10(-7) M) completely abolished the aconitine action on spontaneous IPSC frequency. Likewise removal of extracellular Na(+) completely suppressed the aconitine action. Both Ca(2+)-free external solution or addition of 10(-4) M Cd(2+) to normal solutions eliminated the facilitatory effect of aconitine on the IPSC frequency. Overall these results suggest that aconitine depolarizes the presynaptic membrane by activating voltage-dependent Na(+) channels. Increase of intraterminal Ca(2+) concentration via an activation of voltage-dependent Ca(2+) channels in turn enhances the spontaneous transmitter release from presynaptic nerve terminals. The presynaptic action of aconitine may play a crucial role for membrane excitability of rat VMH neurons.

Studies on the prevalence of complicated atrial arrhythmias, flutter, and fibrillation in patients with reciprocating supraventricular tachycardia before and after successful catheter ablation

Atrial flutter and AF are complications in approximately 30% of cases of paroxysmal supraventricular tachycardia (PSVT)-indicated catheter ablation, and it is of interest to determine if therapeutic modification for PSVT would eliminate combined atrial tachyarrhythmia like atrial flutter and AF. The aim of this study was to determine the incidence and the risk of atrial tachyarrhythmias after catheter ablation of PSVT. A total of 152 patients (age range 12-74, mean 41 +/- 17 years) with accessory pathway (n = 106) and/or dual atrioventricular nodal conduction (n = 46) were enrolled in a 2-year follow-up program after successful catheter ablation. Possible risks on clinical background (age, sex, PSVT duration, hemodynamic instability during attacks), premature atrial contraction (PACs) on Holter monitoring, echocardiographic left atrial size, and electrophysiological property (insertion site, conduction type, effective refractory period) were evaluated. Atrial flutter and AF were complications in 53 (35%) of the subjects, who were elderly and had a longer PSVT history with a larger left atrial dimension and frequent PACs; however, the electrophysiological properties were similar. After a 2-year follow-up period 36 (24%) of the patients still exhibited PAC runs, including 13 (9%) with atrial flutter and AF, each one of whom were complicated with nonlethal cerebral thromboembolism and congestive heart failure. Multiplelogistic-regression analysis revealed that advanced age (> or = 41 years, P = 0.0152) and frequent PACs (> or = 1% of total daily QRS counts, P = 0.0426) on Holter monitoring are the risk factors of PAC runs and/or atrial flutter and AF. In conclusion, successful ablation for PSVT is thought to be beneficial for preventing atrial flutter and AF. However, careful follow-up to monitor for the recurrence and atrial flutter and AF related complications, especially in patients of solitary atrial flutter and AF without reciprocating tachycardia and with frequent PAC.

Molecular typing and epidemiological study of Salmonella enterica serotype Typhimurium isolates from cattle by fluorescent amplified-fragment length polymorphism fingerprinting and pulsed-field gel electrophoresis

One hundred twenty Salmonella enterica serotype Typhimurium strains, including 103 isolates from cattle gathered between 1977 and 1999 in the prefecture located on the northern-most island of Japan, were analyzed by using fluorescent amplified-fragment length polymorphism (FAFLP) and pulsed-field gel electrophoresis (PFGE) to examine the genotypic basis of the epidemic. Among these strains, there were 17 FAFLP profiles that formed four distinct clusters (A, B, C, and D). Isolates that belonged to cluster A have become increasingly common since 1992 with the increase of bovine salmonellosis caused by serotype Typhimurium. PFGE resolved 25 banding patterns that formed three distinct clusters (I, II, and III). All the isolates that belonged to FAFLP cluster A, in which all the strains of definitive phage type 104 examined were included, were grouped into PFGE cluster I. Taken together, these results indicate that clonal exchange of serotype Typhimurium has taken place since 1992, and they show a remarkable degree of homogeneity at a molecular level among contemporary isolates from cattle in this region. Moreover, we have sequenced two kinds of FAFLP markers, 142-bp and 132-bp fragments, which were identified as a polymorphic marker of strains that belonged to clusters A and C, respectively. The sequence of the 142-bp fragment shows homology with a segment of P22 phage, and that of the 132-bp fragment shows homology with a segment of traG, which is an F plasmid conjugation gene. FAFLP is apparently as well suited for epidemiological typing of serotype Typhimurium as is PFGE, and FAFLP can provide a source of molecular markers useful for studies of genetic variation in natural populations of serotype Typhimurium.

[A case of arteriovenous malformation associated with venous malformation]

A case of arteriovenous malformation associated with venous malformation is reported. A 35-year-old male patient suffered intracerebral hemorrhage in the left occipital with acute subdural hematoma. Angiography showed an arteriovenous malformation fed by the left middle cerebral artery. The hematoma and nidus was operatively removed. He also had a venous malformation in the left temporal lobe. This rare case is reported with some discussion.

Impaired exercise-related myocardial uptake of technetium-99m-tetrofosmin in relation to coronary narrowing and diabetic state: assessment with quantitative single photon emission computed tomography

Despite the diagnostic efficacy of stress myocardial perfusion imaging, the correlation between the actual perfusion tracer activity and diseased state of a coronary artery has not been studied in detail. We estimated exercise-related perfusion augmentation in relation to disease states of a coronary artery in diabetic and non-diabetic patients by a newly developed quantitative technetium (Tc)-99m-tetrofosmin myocardial imaging technique. Tc-99m-tetrofosmin tomographic imaging with an exercise-rest protocol was performed in 26 stable coronary patients and in 8 age-matched controls. Percent increase (%IR) in myocardial count during symptom-limited submaximal exercise-stress was calculated in 16 non-infarcted polar map segments and in each coronary territory by a subtraction technique with corrections for physical decay and injected tracer doses, and the results were compared with those of angiographically quantified coronary diameter stenosis (%DS). Percent IR and peak heart rate during exercise showed a positive linear correlation both in coronary territories with significant stenosis (%DS > or = 75%) and in control or nonstenotic (%DS < 75%) territories. The regression line in stenotic regions was, however. significantly (p < 0.01) shifted downward compared to that in non-stenotic regions. Percent IR in stenotic regions showed a significant inverse correlation with %DS. Coronary stenosis of 75% or more was identified by a %IR cutoff value of 40% with 77% sensitivity, 70% specificity, and an accuracy of 72%. In coronary territories with a %DS of less than 75%, %IR in diabetic patients was significantly lower (46+/-15%) than that in nondiabetic patients (61+/-25%). Thus, blunted exercise-related augmentation of myocardial uptake of Tc-99m-tetrofosmin correlates with the severity of coronary narrowing and diabetic state.

Studies on hemodynamic instability in paroxysmal supraventricular tachycardia: noninvasive evaluations by head-up tilt testing and power spectrum analysis on electrocardiographic RR variation

Hemodynamic instability is a crucial determinant of the best therapeutic option in paroxysmal supraventricular tachycardia (PSVT). However, it is still unclear if hemodynamic instability is tachycardia dependent or independent. We performed frequency-domain analysis of electrocardiographic RR variations during induced PSVT and head-up tilt tests after successful ablation to investigate the role of autonomic vasomotor function in hemodynamic instability during PSVT. Thirty-six patients with (syncope group, n = 18) and without (nonsyncope group, n = 18) syncope and/or presyncope during PSVT were enrolled in this study. Serial blood pressure, heart rate, and variations in heart rate during induced PSVT and head-up tilt tests were examined. Initial blood pressure fall and heart rate changes during induced PSVT were greater in the syncope group than in the nonsyncope group. A significant positive linear relationship was found between these two. Delayed blood pressure fall was observed in the syncope group, independent of heart rate changes. Syncope in PSVT could be predicted from the results of head-up tilt tests with 82% accuracy. Heart rate responses after isoproterenol infusion were significantly greater in the syncope group than in the nonsyncope group. The changes in low frequency to high frequency (LF:HF) values during induced PSVT and head-up tilt tests were significantly greater in the syncope group than in the nonsyncope group, and an exponential correlation was found between LF:HF changes in both tests. We conclude that PSVT rate and vasomotor reaction are related with hemodynamic instability during PSVT and head-up tilt testing is a useful method for determining if patients will have syncope during PSVT.

Hybrid Petri net representation of gene regulatory network

It is important to provide a representation method of gene regulatory networks which realizes the intuitions of biologists while keeping the universality in its computational ability. In this paper, we propose a method to exploit hybrid Petri net (HPN) for representing gene regulatory networks. The HPN is an extension of Petri nets which have been used to represent many kinds of systems including stochastic ones in the field of computer sciences and engineerings. Since the HPN has continuous and discrete elements, it can easily handle biological factors such as protein and mRNA concentrations. We demonstrate that, by using HPNs, it is possible to translate biological facts into HPNs in a natural manner. It should be also emphasized that a hierarchical approach is taken for our construction of the genetic switch mechanism of lambda phage which is realized by using HPNs. This hierarchical approach with HPNs makes easier the arrangement of the components in the gene regulatory network based on the biological facts and provides us a prospective view of the network. We also show some computational results of the protein dynamics of the lambda phage mechanism that is simulated and observed by implementing the HPN on a currently available tool.

Increased urinary excretion of macrophage-colony-stimulating factor (M-CSF) in patients with IgA nephropathy: tonsil stimulation enhances urinary M-CSF excretion

Upper respiratory tract infection including chronic tonsillitis is considered to be involved in the onset and/or the progression of IgA nephropathy. It is well known that deterioration of urinary findings occurs after episodes of upper respiratory tract infection in patients with IgA nephropathy. We previously showed that the expression of macrophage-colony-stimulating factor (M-CSF) is increased in the glomeruli of patients with IgA nephropathy and correlated with glomerular mesangial proliferation, suggesting that M-CSF plays an important role in the progression of IgA nephropathy. In the present study, we measured the serum and urinary concentrations of M-CSF in patients with IgA nephropathy associated with chronic tonsillitis. Furthermore, we evaluated the effects of the local provocation test of tonsils (mechanical tonsil stimulation) on the serum and urinary concentrations of M-CSF in the following three groups: (1) IgA nephropathy with severe mesangial proliferation, (2) IgA nephropathy with mild mesangial proliferation, and (3) patients with chronic tonsillitis without renal disease. The serum and urinary levels of M-CSF in the groups with severe and mild IgA nephropathy were significantly higher than those in the chronic tonsillitis group. The urinary M-CSF level but not the serum M-CSF level was positively correlated with the degrees of mesangial proliferation and glomerular M-CSF expression in the renal biopsy specimens. The urinary M-CSF concentration was significantly increased after tonsillitis stimulation in both mild and severe IgA nephropathy groups. Enhanced urinary excretion of M-CSF prolonged for 7 days after tonsil stimulation in the severe IgA nephropathy group; in contrast, the urinay M-CSF level was increased for only 2 days after tonsil stimulation in the mild IgA nephropathy group. The urinary M-CSF level was not changed in the chronic tonsillitis group after tonsil stimulation. The serum concentrations of M-CSF were not changed after tonsil stimulation in these three groups. Our present results suggest that tonsil stimulation contributes to the progression of IgA nephropathy via enhancement of glomerular production of M-CSF. The urinary excretion of M-CSF may be a useful predictor to evaluate the relevance of chronic tonsillitis to the disease and the indication of tonsillectomy in patients with IgA nephropathy.

Impaired myocardial accumulation of 15-(p-iodophenyl)-9-(R,S)-methylpentadecanoic acid in a patient with hypertrophic cardiomyopathy and exercise-induced ischemia due to vasospasm

We encountered a patient with hypertrophic cardiomyopathy complicated with exercise-induced myocardial ischemia. Exercise-stress 99mTc-tetrofosmin imaging demonstrated reversible ischemia in the lateral wall, whereas resting fatty acid imaging with a new beta-methyl branched fatty acid analogue, I-123-15-(p-iodophenyl)-9-(R,S)-methylpentadecanoic acid (123I-9-MPA), showed impaired uptake and accelerated washout kinetics in the inferoapical and posteroseptal walls but not in the ischemia-related region. These findings suggest that the metabolic derangement is closely related to cardiomyopathy per se rather than exercise-induced myocardial ischemia in this patient with hypertrophic cardiomyopathy and a spastic coronary lesion so that myocardial perfusion and 123I-9-MPA imagings may contribute to clarifying the etiological background of impaired myocardial fatty acid metabolism.

Genetic analysis of temperature-dependent transmission of mitochondrial DNA in Drosophila

In artificially induced mitochondrial DNA (mtDNA) heteroplasmy in Drosophila, the effects of chromosome substitution on temperature-dependent selection in mtDNA transmission were investigated. Using two strains of D. melanogaster, bw;e11 and y;bw;st, which showed a different temperature dependency in mtDNA transmission, chromosomes were substituted reciprocally, and mtDNA of D. mauritiana was introduced into each newly constructed strain. For each heteroplasmy, the transmission of mtDNA was examined at 25 degrees C and 19 degrees C. When either the second or the third chromosome of the y;bw;st strain was substituted with that of the bw;e11 strain, the temperature-dependent selection in mtDNA transmission was altered. The selection was not changed when either the second or the third chromosome of the bw;e11 strain was substituted with that of the y;bw;st strain, or even when both the second and the third chromosomes of the bw;e11 strain were substituted with those of the y;bw;st strain. These results suggest that the temperature-dependent selection in mtDNA transmission is co-operatively regulated by gene products that are encoded by the X, second and third chromosomes.