bluuebunny/crossref_metadata_2025 huggingface dataset:
Swedish engineering employers: The search for industrial peace in the absence of centralised collective bargaining
Authors: Sheldon Peter , Thornthwaite Louise
Published: April 2004

The Swedish engineering employers’ association recently shifted away from the dramatic decentralisation of bargaining it had pioneered. Behind this shift were employer desires for better guarantees of industrial peace. The authors conclude by stressing the importance of the relationships between employer strategy, historical contingency and debates on bargaining structure.
A New Form of Chinese Human Resource Management? Personnel and Labour‐Management Relations in Chinese Township and Village Enterprises: A Case‐Study Approach
Authors: Ding Daniel Z. , Lan Ge , Warner Malcolm
Published: April 2004

Township and Village Enterprises (TVEs) in China have in the last decade played an increasingly important role in the Chinese economy, employing over 120 million workers. This article examines their human resources, personnel and labour‐management relations, based on in‐depth case studies of a selected number of TVEs located in southern China, reflecting the influence of diversification, local labour‐market conditions and marketisation.
Cyclic AMP phosphodiesterase activity in human gingival carcinoma
Authors: Spoto Giuseppe , Fioroni Massimiliano , Rubini Corrado , Di Nicola Maurizio , Di Pietrantonio Francesco , Di Matteo Elisabetta , Piattelli Adriano
Published: April 2004

Background:  The phosphodiesterases (PDEs) are responsible for the hydrolysis of the second messengers, cyclic AMP (cAMP) and cyclic GMP (cGMP), to their corresponding monophosphates with a fundamental role in the transduction of the intracellular signals. At least 11 different enzymatic isoforms have been identified, which are listed according to their specificity or affinity for the substratum, identity of the amino acid sequence, cofactor, and inhibitor sensitivity. Variations in PDE activity have been found in different pathologies, and they have also been correlated to different pathological e/o physiological mechanisms, such as cellular differentiation, apoptosis, and tumor invasivity.

Objectives:  In this study, we have evaluated cAMP PDE activity in patients with carcinoma of the gingiva, with the purpose of correlating differences in its development and progression. The same enzymatic activity has been used to evaluate differences between patients with lymph node involvement (group N+), and patients without lymph node involvement (N−).

Materials and Methods:  The analysis of PDE activity and the cAMP assay was performed by reverse‐phase HPLC on samples of fresh or frozen gingival tissues. Analysis of cAMP was confirmed with the enzyme‐linked immunoabsorption assay (EIA).

Results and Conclusions:  The differences between control and N– groups (P = 0.0433), and between control and N+ groups (P = 0.0156) were statistically significant. PDE3A was also evaluated immunohistochemically in lymph‐node negative and lymph‐node positive cases. The differences between the two groups were statistically significant (P = 0.0397).
Characterization of lymphoid infiltrates in chronic obstructive sialadenitis associated with sialolithiasis
Authors: Teymoortash Afshin , Tiemann Markus , Schrader Carsten , Werner Jochen A.
Published: April 2004

Background:  Chronic obstructive sialadenitis is characterized by acinar atrophy, lymphocytic infiltrates and progressive fibrosis. The immunological mechanisms involved in the pathogenesis of this disease are, for the most part, unknown. The aim of the present study was to characterize the lymphocytic infiltrates in chronic obstructive sialadenitis associated with sialolithiasis.

Methods:  Paraffin‐embedded tissue samples from 23 affected submandibular glands were immunostained for T‐cells (CD3, CD4, CD8), cytotoxic T‐cells (granzyme B), B‐cells (CD20), plasma cells (CD38) and macrophages (Ki‐M1P).

Results:  CD4‐positive subsets were the predominant cells, and they were located mainly periductally. Isolated intraepithelial CD8‐positive cytotoxic T‐cells associated with ductal epithelial cell destruction were observed in all cases. B lymphocytes were restricted to lymphoid follicles located periductally and around intralobular ducts. In early stages of the disease, a large number of CD38‐positive plasma cells were distributed diffusely in the periacinar area. With progression of the disease, conspicuous clusters of plasma cells were located especially between atrophic acini adjacent to fibrotic tissue. An intimate relation between the lymphocytic infiltrates and the ductal epithelium, the target of the inflammatory process, was observed.

Conclusion:  The composition and distribution of inflammatory cells suggest that intraepithelial infectious agents may be the cause of the inflammatory reaction and the progressive fibrosis in this disease.
Adenoid cystic carcinoma associated with salivary duct cyst in the sublingual gland
Authors: Ogawa Yuzo , Kishino Mitsunobu , Nakazawa Mitsuhiro , Iwai Soichi , Ohta Yoshiyuki , Ishida Takeshi , Yura Yoshiaki , Ijuhin Naokuni
Published: April 2004

We described an extremely rare case of adenoid cystic carcinoma associated with salivary duct cyst in the sublingual gland of a 40‐year‐old Japanese woman. The tumor was growing from the cyst wall and almost occluded the cyst lumen. The epithelium lining the cyst lumen contained both keratin 19‐positive cells and α‐smooth muscle actin‐positive cells, indicating the cyst being derived from the acinus/intercalated duct of the sublingual gland. Therefore, our case has presented for the first time a direct evidence that adenoid cystic carcinoma arises from acinus/intercalated duct.
Friction melanosis: a clinical, histologic, and ultrastructural study in Jordanian patients
Authors: Al‐Aboosi Mustafa , Abalkhail Ali , Kasim Omer , Al‐Khatib Aymen , Qarqaz Firas , Todd David , Al‐Khidour Munir , Obeidate Fawaz
Published: April 2004

Background  Friction melanosis (FM) is an acquired pigmentary disorder mainly affecting young people. The primary skin regions affected are located over the osseous prominences, especially the clavicular zone and upper back. Our purpose in this study was to report the clinical spectrum, histologic findings, and ultrastructural features of FM in Jordanian patients.

Methods  Thirteen patients with FM (10 women and three men) were studied. The patients were seen at Princess Basma Teaching Hospital in north Jordan between 1999 and 2001.

Results  Eleven patients presented with asymptomatic, diffuse, brownish patches and two presented with mottled patches on the skin over the trunk bones and limbs. All had a history of rubbing their skin repeatedly with scrub pads (loofah) or bathroom towels. Ten of the 13 cases were studied histologically. Skin biopsies from four patients were examined ultrastructurally. Both histologic and electron microscopic examination of the biopsies from our patients showed a marked increase in melanin and melanin incontinence, with a lack of amyloid in the upper dermis.

Conclusions  FM is infrequently seen in north Jordan. We believe that repeated frictional trauma from clothing or scrub pads against the skin overlying the bony protuberances is fundamental in its pathogenesis. Other factors, such as scrub pads made of rough material (loofah), dark skin type, and individual variability, may also play a role in the pathogenesis. We advise patients not to use rough scrub pads during bathing, to avoid rubbing the skin overlying the bony prominences, to avoid rubbing vigorously, and to use a soft cotton pad instead.
Cutaneous sporotrichosis in Bangalore, southern India
Authors: Mohan Nagamani , Jayaseelan Elizabeth , Abraham Anil , Rajendran Srangipani C. , Stephen John , Sharief Shameen , Macaden Ragini
Published: April 2004

Background  Sporotrichosis is a granulomatous infection caused by Sporothrix schenkii. Although world‐wide in distribution, only four cases have been reported from southern India to date.

Methods  The medical records of all cases seen at the Department of Dermatology at St John's Medical College Hospital, Bangalore, over the last 15 years were reviewed.

Results  A total of seven cases of sporotrichosis were seen in this 15‐year period.

Conclusion  Sporotrichosis is considered to occur only sporadically in southern India. Our findings suggest that this may be a result of reporting bias.
Satellite repigmentation after punch grafting
Authors: Agarwal Uma Shankar
Published: April 2004

Punch grafting is an established treatment modality for management of localized, nonprogressive vitiligo resistant to conventional therapies.1 In our set up, punch grafting is routinely carried out in focal vitiligo, segmental vitiligo and even in few cases of generalized vitiligo, especially when it is a serious cosmetic problem.2 However, the procedure is adopted only when the disease is stable for a sufficient period. All patients are routinely kept on psoralen tablets and ultraviolet light exposure from sunlight (PUVA sol therapy) after 2–3 weeks of punch grafting. Interestingly, follow up of such patients revealed conspicuous repigmentation in surrounding ungrafted patches in four of the patients (out of 55 follow‐up cases). Herein, this phenomenon has been aptly termed satellite repigmentation (SR). To the best of our knowledge, no other report documenting SR after punch grafting exists in the medical literature. We report the observations of these four patients.
Comparative study of the efficacy of combined cryotherapy and intralesional meglumine antimoniate (Glucantime®) vs. cryotherapy and intralesional meglumine antimoniate (Glucantime®) alone for the treatment of cutaneous leishmaniasis
Authors: Asilian A. , Sadeghinia A. , Faghihi G. , Momeni A.
Published: April 2004

Background  Cutaneous leishmaniasis (CL) is a parasitic disease caused by Leishmania species. There is a need for more effective and less time‐consuming therapeutic methods for this condition.

Aim  To evaluate the efficacy of combined cryotherapy and intralesional meglumine antimoniate (MA) (Glucantime®, Specia, Paris, France) for the treatment of CL.

Methods  Patients were divided into three groups: Group 1, 100 patients with 149 lesions were treated with cryotherapy plus intralesional MA; Group 2, 200 patients with 230 lesions were treated with cryotherapy; Group 3, 100 patients with 160 lesions were treated with intralesional MA. These groups were followed for 6 months after the end of treatment.

Results  The results showed complete cure in 90.9% of cases in Group 1, 57.15% of cases in Group 2, and 55.63% of cases in Group 3. The difference between Group 1 and the other groups was statistically significant (P < 0.05).

Conclusions  Combined cryotherapy and intralesional MA is more effective than either cryotherapy or intralesional MA alone for the treatment of CL.
Motor neuron disease group accompanied by inclusions of unidentified protein signaled by ubiquitin
Authors: Ikeda Kenji , Tsuchiya Kuniaki
Published: April 2004

Peculiar tau‐negative, ubiquitin‐positive inclusions appear in dementia with ALS (ALS‐D), the majority of lobar atrophy (Pick's disease) without Pick body and a small portion of ALS. Another common neuropathological lesion in these diseases is the motor neuron involvement with the degenerative processes. The lower motor neuron is predominantly involved in ALS and ALS‐D while the upper motor neuron is predominantly involved, but in varying degrees in a considerable number of patients with lobar atrophy that lack Pick bodies. There are, however, some points that have yet to be elucidated. The boundary between these diseases is not always clear and a significant number of cases are considered to be the transitional form. Lobar atrophy without Pick body seems to be a heterogeneous disease group. The nature of ubiquitin inclusions also needs to be clarified. Nevertheless, we postulate that these diseases are grouped with the concept of motor neuron disease‐inclusion dementia.
Angiotensin II type 1 receptor mRNA and its protein expression in human pancreatic cancer cell lines
Authors: Jiang Hua , Li Zhao Shen , Xu Guo Ming , Tu Zhen Xing , Gong Yan Fang
Published: April 2004

OBJECTIVE:  The incidence of pancreatic cancer is increasing in China, and in many patients the surrounding lymphatics have already been invaded and there is blood‐borne metastasis at the time of diagnosis. Additionally, pancreatic cancer is largely refractory to conventional therapies. Therefore, to improve its prognosis, it is important to resolve the problem of its growth. Angiotensin II type 1 receptor (AT1) stimulates the growth and angiogenesis of pancreatic cancer and a selective AT1 antagonist could inhibit these effects. The present study aimed to investigate the expression of AT1 in pancreatic cancer cell lines to provide the theoretical basis for its treatment.

METHODS:  The pancreatic cancer cell lines were SW1990, PaTu8988s and PANC‐1. RT‐PCR was used to detect the AT1 mRNA expression, and ABC immunocytochemical staining and SDS‐PAGE were used to detect the expression of AT1 protein.

RESULTS:  Both AT1 mRNA and protein were expressed in all three cell lines. The AT1 protein was found on the cell membrane and in the cytoplasm of these cells. The AT1 protein (44 × 103) was also demonstrated by SDS‐PAGE.

CONCLUSION:  The results suggest that AT1 plays an important role in the growth of pancreatic cancer and its inhibition may be a therapeutic strategy.
Increased activity of the intestinal mucosal mast cells in rats with multiple organ failure
Authors: Tang Cheng Wei , Lan Cheng , Liu Rui
Published: April 2004

OBJECTIVE:  This study was undertaken to evaluate the changes in the activity of the intestinal mucosal mast cells (IMMC) in multiple organ failure (MOF).

METHODS:  A rat model of MOF was induced by intraperitoneal injection of zymosan. Both the functional alterations and the pathological morphology of essential organs, such as small intestine, liver, kidney and the lungs, were evaluated. The concentrations of histamine and tumor necrosis factor α (TNF‐α) in plasma and small intestinal tissue were detected by fluorimetric assay and enzyme‐linked immunosorbent assay, respectively. The ultrastructural changes of the IMMC from the MOF rats were evaluated by transmission electron microscopy.

RESULTS:  Zymosan induced obvious inflammatory morphology and functional impairment in the essential organs of the rats that were indicative of the characteristic changes in MOF. There was a significantly decreased concentration of histamine in the intestinal tissue of the MOF rats when compared with the normal controls (8.67 ± 1.16 vs 11.63 ± 1.97 ng/g protein, P < 0.01), whereas the plasma histamine concentration showed no significant changes. The concentration of TNF‐α was elevated significantly in both the intestinal tissue and plasma of MOF rats. Furthermore, both the increased number and level of degranulation of the IMMC in the gut tissue was marked in MOF rats.

CONCLUSION:  The results suggest that the histamine and TNF‐α released from activated IMMC play an important role in the development of MOF.
The Knowledge Worker, the Manager‐academic and the Contemporary UK University: New and Old Forms of Public Management?
Authors: Deem Rosemary
Published: April 2004

This paper explores how far the expectations of and the practices and technologies used by academics in management roles in UK higher education at the end of the twentieth and beginning of the twenty‐first centuries appear to differ from those used in the 1960s, 1970s and 1980s. The system of higher education in the UK is explained and then concepts of new managerialism and academic knowledge work are discussed. Next the changing policy context of UK higher education since the 1960s is examined. The paper then uses illustrations of perceptions of contemporary changes to changing expectations about the roles of academics in management roles in UK universities from a recent UK Economic and Social Research Council funded project on ‘New Managerialism and the Management of UK Universities’. Finally, using research and insider accounts of university management and governance from the 1960s onwards, the paper examines the extent to which so‐called new forms of management of higher education may have predated the 1990s. It is suggested that whilst some elements of the management of universities remain intact (role titles, leadership of academics, oversight of teaching and research) from the 1960s and 1970s, radical policy changes from the 1980s onwards have meant that major shifts in what was expected of academics in management roles began in the early to mid‐1980s.
Measuring Operations: An Analysis of US Private Colleges and Universities’ Financial Statements
Authors: Fischer Mary , Gordon Teresa P. , Greenlee Janet , Keating Elizabeth K.
Published: April 2004

As events in the business sector have highlighted, companies can play by the rules and yet produce misleading financial statements. This study examines non‐governmental organizations that provide a substantial portion of higher education in the United States. We seek to determine whether private colleges and universities take advantage of the discretion available to them under accounting and auditing standards to present an operating measure in their statement of activities. We find that nearly 60% of schools report an operating measure but the items included or excluded from operations vary widely.
Corporatization of National Universities in Japan: Revolution for Governance or Rhetoric for Downsizing?
Authors: Yamamoto Kiyoshi
Published: April 2004

As in a number of other countries, Japanese higher education institutions have faced pressure to reduce costs and respond to ‘market pressures’. This has included proposals by the national government to introduce competition, ‘agencify’ or corporatize universities and give management autonomy for universities in a hope that this will improve efficiency. The proposals however, are considered not a linear development but a radical change, because they go beyond an organizational reform as agencification that has been already adopted into some public services in 2001. Consequently, this paper analyses why this new policy change has suddenly happened and examines whether the new framework will be able to improve performance through enhancing autonomy. Investigating the process, we show that the corporatization of national universities has been progressed as the rhetoric for enhancing university autonomy and excellence, while the reality has shifted into a public sector reform as downsizing under the fiscal stress and the government control on performance might be much stronger.
A Mathematical Analysis for the Cardiovascular Control Adaptations in Chronic Renal Failure
Authors: Lerma Claudia , Minzoni Antonmaria , Infante Oscar , José Marco V.
Published: April 2004

Abstract:  A model of baroreflex control of blood pressure (BP) is proposed in terms of a delay differential equation and this is used to predict the adaptation of short‐term cardiovascular control in chronic renal failure (CRF) patients. Cardiac pump dynamics are explored by means of plots of blood flow vs. mean BP. The parameters of the model were determined from available data and from a sensitivity analysis. The model predicts stable and unstable equilibria close to the steady BP. It is shown that the unstable equilibrium point generates a quasiperiodic solution with two main harmonics for healthy subjects. We also show that the parameters for CRF patients predict solutions whose spectra exhibit a small high frequency component. This is due to the coalescence of the equilibrium points. The heart rate variability (HRV) time series and power spectra from healthy volunteers and CRF patients were compared with the model predictions. As an adequate measure of the sympathovagal balance we use the LF/HF index obtained from the power spectrum. The model allows the interpretation of the variability of the LF/HF index in terms of a specific set of cardiovascular parameters which are known to change from healthy to CRF patients. Comparisons of the changes in the LF/HF index predicted by the model are in agreement with actual observations for both the healthy and the CRF patients. These results show that the cardiac pump has a more restricted response in CRF patients. The model quantifies the cardiovascular adaptations to the CRF condition in terms of increased peripheral resistance and baroreflex delay and decreased arterial compliance, cardiac period, and stroke volume.
Arresting Dialysis‐Related Amyloidosis: A Prospective Multicenter Controlled Trial of Direct Hemoperfusion with a β2‐Microglobulin Adsorption Column
Authors: Gejyo Fumitake , Kawaguchi Yoshindo , Hara Shigeko , Nakazawa Ryoichi , Azuma Nakanobu , Ogawa Hiroshi , Koda Yutaka , Suzuki Masashi , Kaneda Hiroshi , Kishimoto Hidefumi , Oda Mizue , Ei Kyoko , Miyazaki Ryoichi , Maruyama Hiroki , Arakawa Masaaki , Hara Mitsuru
Published: April 2004

Abstract:  We investigated the clinical efficacy of direct hemoperfusion with a β2‐microglobulin (β2‐m) adsorption column for the treatment of patients with dialysis‐related amyloidosis. A 2‐year prospective controlled study was performed to compare the effects of passaging blood through a (β2‐m) adsorption column (Lixelle) before it is passaged through the dialysis polysulfone membrane on the severity of amyloidosis in these individuals. Patients (n = 22) whose blood went through the Lixelle column prior to dialysis had a higher β2‐m removal rate compared to an equal number of controls, and they showed earlier improvement in their symptoms which included impaired daily  activities,  joint  stiffness,  and  pain.  The  appearance of additional bone cysts was prevented in pre‐adsorbed patients but not in the controls. Thus, the Lixelle column is useful in preventing the progression of dialysis‐related amyloidosis and in ameliorating or arresting the progression of the  symptoms  of  this  disorder.
Assessment of Diastolic Function in Endomyocardial Fibrosis: Value of Flow Propagation Velocity
Authors: Salemi Vera M.C. , Picard Michael H. , Mady Charles
Published: April 2004

Abstract:  Endomyocardial fibrosis is manifested mainly by diastolic heart failure. However, diastolic function has not been well characterized in this disease. The aim of this study was to characterize left ventricular (LV) diastolic function in endomyocardial fibrosis (EMF) by echocardiography. Eighteen patients with LV EMF and 18 healthy subjects were studied. Cardiac volumes and ejection fraction were assessed by Simpson's method. Pulsed‐wave Doppler was used to obtain mitral and pulmonary venous flow velocities and grade diastolic function. Pulsed‐wave tissue Doppler imaging velocities along the septal side of mitral annulus, flow propagation velocity (Vp) of the early diastolic mitral inflow, and myocardial performance index were obtained. According to this grading method, four patients with normal diastolic function, five with impaired relaxation, five with pseudonormal, and four with a restrictive pattern were found. A positive correlation of these diastolic function grades and NYHA functional class was found (r = 0.66, P = 0.003). By “stepwise” logistic regression the best index that discriminated EMF patients from controls was Vp. The probability of occurrence of EMF = exp(7.9288 − 0.1366 Vp)/1 + exp(7.9288 − 0.1366 Vp). A wide range of diastolic function grades is found in patients with EMF and these correlated with functional class. Delayed myocardium relaxation, as reflected by altered Vp, was a frequent finding, making Vp the most useful index to discriminate  EMF  patients.
Numerical Simulation of Electroporation in Spherical Cells
Authors: Ramos Airton , Suzuki Daniela Ota Hisayasu , Marques Jefferson Luiz Brum
Published: April 2004

Abstract:  This article presents a numerical study of the electroporation process of spherical cells suspended in an electrolyte solution, using the equivalent circuit method (ECM) for field calculation proposed by Ramos et al. A model for the electric conductance of the cell membrane derived from the analytical and experimental results obtained by Glaser et al. for planar lipidic membranes was applied. The influence of the cell concentration and membrane properties (described in the model) on the membrane current, membrane potential, and dependence of the electrolyte conductivity on the applied electric field was studied. These results clarify the electric events connected with the pore opening process and allow the planning of experimental approaches to study reversible membrane  rupture  in  real  cells.
Comparison of Cryopreserved Homografts and Decellularized Porcine Heterografts Implanted in Sheep
Authors: Costa Francisco Diniz Affonso da , Dohmen Pascal Maria , Lopes Sergio Veiga , Lacerda Guilherme , Pohl Felipe , Vilani Ricardo , Brenner Affonso da Costa Marise , Vieira Eduardo Discher , Yoschi S. , Konertz Wolfgang , Costa Iseu Affonso da
Published: April 2004

Abstract:  This study evaluated cryopreserved homografts (Group 1) and porcine heterografts decellularized with deoxicholic acid (Group 2), implanted in the right ventricular outflow tract of juvenile sheep. Two groups with four animals in each were used and all animals survived with good outcome. Animals were sacrificed 90 or more days after surgery (90–150 days). On the third and fifth postoperative months they were submitted to echocardiographic examination with normal function and appearance observed for both groups. Explants were evaluated through histological analysis, atomic spectrophotometry and radiological examination. Calcium content was higher in the cusps of cryopreserved homografts, despite an otherwise similar macroscopic appearance between grafts of both groups. Decellularized heterografts were progressively  repopulated  by  autologous  cells  suggesting some regenerative ability and longer durability than conventional homografts.
The human enteric nervous system
Authors: Schemann M. , Neunlist M.
Published: April 2004

Decades of work in animal models have demonstrated that the enteric nervous system (ENS) plays a key role in controlling gut functions. Recent advances made it possible to extend such studies to the ENS of man in health and even in disease. Such studies have already provided new insights into the pathophysiology of inflammatory and possibly functional bowel diseases. Studies on human ENS revealed both important similarities and differences between the ENS of man and of experimental animals. Here we summarize the current state of knowledge of the electrophysiology and neurochemistry of the human ENS, including relevant reflex mediated functions in the human gut. Additionally, we review disease associated changes in human ENS properties. Finally, we highlight some research areas that hold special promise in advancing our understanding of the human ENS.
Sensory mechanisms: transmitters, modulators and reflexes
Authors: Raybould H. E. , Cooke H. J. , Christofi F. L.
Published: April 2004

The enteric nervous system in combination with inputs from parasympathetic and sympathetic nerves regulate the contractile, secretory and vasomotor activity of the gastrointestinal track via neural reflexes. Sensory elements which may be present in specialized neurones, enteroendocrine cells or mast cells detect changes in force, chemical composition or even foreign antigens. Sensory elements signal the enteric nervous system to correct these changes by altering contractile activity, secretion and blood flow. Advances have been made in understanding the sensory mechanisms that are involved in 5‐hydroxytryptamine (5‐HT) release from enterochromaffin cells (EC) or a model for EC cells. These advances relate to roles for ATP and its metabolites ADP and adenosine in mechanotransduction and a role for a sodium glucose cotransporter, a SGLT‐like protein, in chemotransduction.
Pharmacology and function of nicotinic acetylcholine and P2X receptors in the enteric nervous system
Authors: Galligan J. J. , North R. A.
Published: April 2004

There are many cell surface receptors expressed by neurones in the enteric nervous system (ENS). Ligand‐gated ion channels are an important class of receptors expressed by enteric neurones. This review will focus on nicotinic acetylcholine receptors (nAChRs) and P2X receptors for ATP, as these receptors contribute to fast synaptic transmission in identified pathways in the ENS. There are multiple subunit proteins that compose nAChRs and P2X receptors in the nervous system. Functional and pharmacological studies indicate that the predominant class of nAChR mediating fast synaptic transmission in enteric neurones is composed of α3 and β4 subunits. P2X receptors mediating fast synaptic excitation are predominately P2X2 homomeric receptors.
Carbon monoxide is an endogenous hyperpolarizing factor in the gastrointestinal tract
Authors: Szurszewski J. H. , Farrugia G.
Published: April 2004

In all mammalian species examined to date, there is a 10 mV or more gradient in resting membrane potential across the wall of the gastric antrum, small intestine and colon, and an even larger gradient along the long axis of the stomach. These voltage gradients, which may be considered biological rheostats, are central to the ability of circular smooth muscle to vary the strength of contraction from weak to propulsive and occluding. In this short review, we consider recent data that support the hypothesis that carbon monoxide generated in interstitial cells of Cajal is a hyperpolarizing factor for circular smooth muscle and the root of the essential voltage gradients.
Delayed shrinkage triggered by the Na+–K+ pump in terbutaline‐stimulated rat alveolar type II cells
Authors: Hosoi Keita , Min Kyong‐Yob , Iwagaki Akitaka , Murao Hitoshi , Hanafusa Toshiaki , Shimamoto Chikao , Katsu Ken‐ichi , Kato Masumi , Fujiwara Shoko , Nakahari* Takashi
Published: April 2004

Terbutaline (10 μm) induced a triphasic volume change in alveolar type II (AT‐II) cells: an initial shrinkage (initial phase) followed by cell swelling (second phase) and a gradual shrinkage (third phase). The present study demonstrated that the initial and the third phases are evoked by the activation of K+ and Cl− channels and the second phase is evoked by the activation of Na+ and Cl− channels. Ouabain blocked the third phase, although it did not block the initial and second phases. This suggests that the third phase is triggered by the Na+–K+ pump. Tetraethylammonium (TEA, a K+ channel blocker) decreased the volume of AT‐II cells and enhanced the terbutaline‐stimulated third phase, although quinidine, another K+ channel blocker, increased the volume of AT‐II cells. The TEA‐induced cell shrinkage was inhibited by ouabain, suggesting that TEA increases Na+–K+ pump activity. Ba2+, 2,3‐diaminopyridine and a high [K+]o (30 mm) similarly decreased the volume of AT‐II cells. These findings suggest that depolarization induced by TEA increases Na+–K+ pump activity, which increases [K+]i. This [K+]i increase, in turn, hyperpolarizes membrane potential. Valinomycin (a K+ ionophore), which induces hyperpolarization, decreased the volume of AT‐II cells and enhanced the third phase in these cells. In conclusion, in terbutaline‐stimulated AT‐II cells, an increase in Na+–K+ pump activity hyperpolarizes the membrane potential and triggers the third phase by switching net ion transport from NaCl entry to KCl release.
Vulnerability to ventricular arrhthmias and heterogeneity of action potential duration in normal rats
Authors: Stilli Donatella , Berni Roberta , Bocchi Leonardo , Zaniboni Massimiliano , Cacciani Francesca , Sgoifo Andrea , Musso Ezio
Published: April 2004

In normal rats, we analysed the arrhythmogenic role of intrinsic action potential duration (APD) heterogeneity. In each animal, ventricular arrhythmic events (VAEs) occurring spontaneously and during the exposure to an acute social challenge were telemetrically recorded. Action potentials were recorded from isolated left ventricular myocytes, at a pacing rate of 5 Hz (patch clamp: current‐clamp mode). APDs were measured at −20 mV, −30 mV, −40 mV, −50 mV and −60 mV. The difference between the shortest and the longest APD was also computed, as an index of individual APD heterogeneity. Animals predisposed to stress‐induced arrhythmias showed higher values of APD and APD heterogeneity as compared with the remaining rats. We concluded that, in the normal heart, a large intrinsic APD heterogeneity resulting from specific electrophysiological properties of ventricular myocytes is not in itself arrhythmogenic, but can predispose towards arrhythmia development under certain conditions, such as autonomic activation.
The effects of insulin on mesenteric blood flow in anaesthetized pigs
Authors: Grossini E. , Battaglia A. , Bona G. , Mary D. A. S. G. , Molinari C. , Vacca G.
Published: April 2004

Infusion of insulin in anaesthetized pigs has been shown to cause an increase in renal blood flow and a decrease in coronary blood flow, which were the net result of a vasoconstriction involving sympathetic α‐adrenoceptor‐mediated mechanisms and of a local vasodilatation involving the endothelial release of nitric oxide. In the present study, the effect of insulin on superior mesenteric blood flow was examined in pentobarbitone‐anaesthetized pigs at constant heart rate, aortic blood pressure, left ventricular contractility and blood levels of glucose and potassium. In 10 pigs, infusion of 0.004 IU kg −1 min−1 of insulin increased mesenteric flow. In five of these pigs, intravenous phentolamine enhanced the increase in mesenteric flow elicited by insulin, a response which was abolished by the subsequent injection of Nω‐nitro‐l‐arginine methyl ester (l‐NAME) into the mesenteric artery. In the remaining five pigs, infusion of insulin after intramesenteric injection of l‐NAME caused a decrease in mesenteric flow. This response was abolished by the subsequent intravenous administration of phentolamine. The present study showed that infusion of insulin in anaesthetized pigs primarily caused a mesenteric vasodilatation, which was the net result of two opposite effects, namely a predominant vasodilatation mediated by the endothelial release of nitric oxide and a sympathetic vasoconstrictor mechanism mediated by α‐adrenoceptors.
Effects of intracellular stores and extracellular Ca2+ on Ca2+‐activated K+ currents in mature mouse inner hair cells
Authors: Marcotti Walter , Johnson Stuart L. , Kros Corné J.
Published: April 2004

Ca2+‐activated K+ currents were studied in inner hair cells (IHCs) of mature mice. IK,f, the large‐conductance Ca2+‐activated K+ current (BK) characteristic of mature IHCs, had a fast activation time constant (0.4 ms at −25 mV at room temperature) and did not inactivate during 170 ms. Its amplitude, measured at −25 mV, and activation time constant were similar between IHCs in the apical and basal regions of the cochlea. IK,f was selectively blocked by 30 nm IbTx but was unaffected by superfusion of Ca2+‐free solution, nifedipine or Bay K 8644, excluding the direct involvement of voltage‐gated Ca2+ channels in IK,f activation. Increasing the intracellular concentration of the Ca2+ chelator BAPTA from 0.1 mm to 30 mm reduced the amplitude of IK,f at −25 mV and shifted its activation by 37 mV towards more depolarized potentials. A reduction in the size of IK,f and a depolarizing shift of its activation were also seen when either thapsigargin and caffeine or ryanodine were added intracellularly, suggesting that IK,f is modulated by voltage‐dependent release from intracellular Ca2+ stores. Mature IHCs had a small additional Ca2+‐activated K+ current (IK(Ca)), activated by Ca2+ flowing through L‐type Ca2+ channels. This current was still present during superfusion of either IbTx (60 nm) or apamin (300 nm) but was abolished in Cs+‐based intracellular solution or during superfusion of 5 mm TEA, suggesting the presence of an additional BK‐channel type. Current clamp experiments at body temperature show that IK,f, but not IK(Ca), is essential for fast voltage responses of mature IHCs.
Peripheral nerves in the rat exhibit localized heterogeneity of tensile properties during limb movement
Authors: Phillips J. B. , Smit X. , Zoysa N. De , Afoke A. , Brown R. A.
Published: April 2004

Peripheral nerves in the limbs stretch to accommodate changes in length during normal movement. The aim of this study was to determine how stretch is distributed along the nerve relative to local variations in mechanical properties. Deformation (strain) in joint and non‐joint regions of rat median and sciatic nerves was measured in situ during limb movement using optical image analysis. In each nerve the strain was significantly greater in the joint rather than the non‐joint regions (2‐fold in the median nerve, 5‐ to 10‐fold in the sciatic). In addition, this difference in strain was conserved in the median nerve ex vivo, demonstrating an in‐built longitudinal heterogeneity of mechanical properties. Tensile testing of isolated samples of joint and non‐joint regions of both nerves showed that joint regions were less stiff (more compliant) than their non‐joint counterparts with joint: non‐joint stiffness ratios of 0.5 ± 0.07 in the median nerve, and 0.8 ± 0.02 in the sciatic. However, no structural differences identified at the light microscope level in fascicular/non‐fascicular tissue architecture between these two nerve regions could explain the observed tensile heterogeneity. This identification of localized functional heterogeneity in tensile properties is particularly important in understanding normal dynamic nerve physiology, provides clues to why peripheral nerve repair outcomes are variable, and suggests potential novel therapeutic targets.
Endothelial Cells Stimulate Self-Renewal and Expand Neurogenesis of Neural Stem Cells
Authors: Shen Qin , Goderie Susan K. , Jin Li , Karanth Nithin , Sun Yu , Abramova Natalia , Vincent Peter , Pumiglia Kevin , Temple Sally
Published: April 2004

Neural stem cells are reported to lie in a vascular niche, but there is no direct evidence for a functional relationship between the stem cells and blood vessel component cells. We show that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production. Both embryonic and adult neural stem cells respond, allowing extensive production of both projection neuron and interneuron types in vitro. Endothelial coculture stimulates neuroepithelial cell contact, activating Notch and Hes 1 to promote self-renewal. These findings identify endothelial cells as a critical component of the neural stem cell niche.
Hydrocarbons in Hydrothermal Vent Fluids: The Role of Chromium-Bearing Catalysts
Authors: Foustoukos Dionysis I. , Seyfried William E.
Published: April 2004

Fischer-Tropsch type (FTT) synthesis has long been proposed to account for the existence of hydrocarbons in hydrothermal fluids. We show that iron- and chromium-bearing minerals catalyze the abiotic formation of hydrocarbons. In addition to production of methane (CH4aq), we report abiotic generation of ethane (C2H6aq) and propane (C3H8aq) by mineral-catalyzed hydrothermal reactions at 390°Cand 400 bars. Results suggest that the chromium component in ultramafic rocks could be an important factor for FTT synthesis during water-rock interaction in mid-ocean ridge hydrothermal systems. This in turn could help to support microbial communities now recognized in the subsurface at deep-sea vents.
The Structure of the First Coordination Shell in Liquid Water
Authors: Wernet Ph. , Nordlund D. , Bergmann U. , Cavalleri M. , Odelius M. , Ogasawara H. , Näslund L. Å. , Hirsch T. K. , Ojamäe L. , Glatzel P. , Pettersson L. G. M. , Nilsson A.
Published: April 2004

X-ray absorption spectroscopy and x-ray Raman scattering were used to probe the molecular arrangement in the first coordination shell of liquid water. The local structure is characterized by comparison with bulk and surface of ordinary hexagonal ice Ih and with calculated spectra. Most molecules in liquid water are in two hydrogen–bonded configurations with one strong donor and one strong acceptor hydrogen bond in contrast to the four hydrogen–bonded tetrahedral structure in ice. Upon heating from 25°C to 90°C, 5 to 10% of the molecules change from tetrahedral environments to two hydrogen–bonded configurations. Our findings are consistent with neutron and x-ray diffraction data, and combining the results sets a strong limit for possible local structure distributions in liquid water. Serious discrepancies with structures based on current molecular dynamics simulations are observed.
ON THE SECOND CRITICAL FIELD FOR A GINZBURG–LANDAU MODEL WITH FERROMAGNETIC INTERACTIONS
Authors: ALAMA STAN , BRONSARD LIA
Published: April 2004

We consider a two-dimensional Ginzburg–Landau model for superconductors which exhibit ferromagnetic ordering in the superconducting phase, introduced by physicists to describe unconventional p-wave superconductors. In this model the magnetic field is directly coupled to a vector-valued order parameter in the energy functional. We show that one effect of spin coupling is to increase the second critical field Hc2, the value of the applied magnetic field at which superconductivity is lost in the bulk. Indeed, when the spin coupling is strong we show that the upper critical field is no longer present, confirming predictions in the physics literature. We treat the energy density as a measure, and show that the order parameter converges (as the Ginzburg–Landau parameter κ→∞) in an average sense to a constant determined by the average energy.
MULTIPLE HAMILTONIAN STRUCTURE OF BOGOYAVLENSKY–TODA LATTICES
Authors: DAMIANOU PANTELIS A.
Published: April 2004

This paper is mainly a review of the multi-Hamiltonian nature of Toda and generalized Toda lattices corresponding to the classical simple Lie groups but it includes also some new results. The areas investigated include master symmetries, recursion operators, higher Poisson brackets, invariants and group symmetries for the systems. In addition to the positive hierarchy we also consider the negative hierarchy which is crucial in establishing the bi-Hamiltonian structure for each particular simple Lie group. Finally, we include some results on point and Noether symmetries and an interesting connection with the exponents of simple Lie groups. The case of exceptional simple Lie groups is still an open problem.
SELF-ADJOINT OPERATORS AFFILIATED TO C*-ALGEBRAS
Authors: DAMAK MONDHER , GEORGESCU VLADIMIR
Published: April 2004

We discuss criteria for the affiliation of a self-adjoint operator to a C*-algebra. We consider in particular the case of graded C*-algebras and we give applications to Hamiltonians describing the motion of dispersive N-body systems and the wave propagation in pluristratified media.
A MOTIVATION-BASED PLANNING AND EXECUTION FRAMEWORK
Authors: CODDINGTON ALEXANDRA M. , LUCK MICHAEL
Published: April 2004

AI planning systems tend to be disembodied and are not situated within the environment for which plans are generated, thus losing information concerning the interaction between the system and its environment. This paper argues that such information may potentially be valuable in constraining plan formulation, and presents both an agent- and domain-independent architecture that extends the classical AI planning framework to take into account context, or the interaction between an autonomous situated planning agent and its environment. The paper describes how context constrains the goals an agent might generate, enables those goals to be prioritised, and constrains plan selection.
APPLYING CONNECTIONIST MODAL LOGICS TO DISTRIBUTED KNOWLEDGE REPRESENTATION PROBLEMS
Authors: d'AVILA GARCEZ ARTUR S. , LAMB LUÍS C. , BRODA KRYSIA , GABBAY DOV M.
Published: April 2004

Neural-Symbolic Systems concern the integration of the symbolic and connectionist paradigms of Artificial Intelligence. Distributed knowledge representation is traditionally seen under a symbolic perspective. In this paper, we show how neural networks can represent distributed symbolic knowledge, acting as multi-agent systems with learning capability (a key feature of neural networks). We apply the framework of Connectionist Modal Logics to well-known testbeds for distributed knowledge representation formalisms, namely the muddy children and the wise men puzzles. Finally, we sketch a full solution to these problems by extending our approach to deal with knowledge evolution over time.
KEYWORD EXTRACTION FROM A SINGLE DOCUMENT USING WORD CO-OCCURRENCE STATISTICAL INFORMATION
Authors: MATSUO Y. , ISHIZUKA M.
Published: April 2004

We present a new keyword extraction algorithm that applies to a single document without using a corpus. Frequent terms are extracted first, then a set of co-occurrences between each term and the frequent terms, i.e., occurrences in the same sentences, is generated. Co-occurrence distribution shows importance of a term in the document as follows. If the probability distribution of co-occurrence between term a and the frequent terms is biased to a particular subset of frequent terms, then term a is likely to be a keyword. The degree of bias of a distribution is measured by the χ2-measure. Our algorithm shows comparable performance to tfidf without using a corpus.
CASE DISPATCHING VERSUS CASE-BASE MERGING: WHEN MCBR MATTERS
Authors: LEAKE DAVID B. , SOORIAMURTHI RAJA
Published: April 2004

Multi-case-base reasoning (MCBR) extends case-based reasoning to draw on multiple case bases that may address somewhat different tasks. In MCBR, an agent selectively supplements its own case-base as needed, by dispatching problems to external case-bases and using cross-case-base adaptation to adjust their solutions for inter-case-base differences. MCBR has been advocated as a means to facilitate handling large case-bases when storage is limited, or to enable use of distributed case sources. However, this raises an important question: When storage is not an issue, and the cases from all external case sources could be merged into a single case-base, is there any reason for MCBR? This article answers that question with an experimental assessment of how MCBR affects the quality of solutions generated. It demonstrates that for a given local case-base and an external case-base for a task environment that is similar to, but different from, the local task environment, MCBR can improve accuracy compared to merging the case-bases into a single case-base. This improvement holds even if the cross-case-base adaptation method used by MCBR is also applied to the external cases before merging. The article hypothesizes an explanation of this behavior in terms of the ability of MCBR to exploit the tradeoffs between similarity of problems and similarity of solution contexts. It provides experimental evidence to support this hypothesis, and also demonstrates that MCBR is a useful framework for guiding case-base maintenance by selecting cases to add to a case-base.