A method for measuring the attachment strength of the cestode Hymenolepis diminuta to the rat intestine.

A unique adaptation of many internal parasites of mammals is their ability to stay in the intestine for extended periods of time and resist the normal peristaltic movements and forces that push and expel material. To better understand parasite adhesion behaviour and replicate their attachment method in medical devices, an experiment was designed and performed using the rat tapeworm, Hymenolepis diminuta. The experiment employed a tensile test machine and a digital scale and was designed to calculate the attachment strength of the scolex to the mucosa through the change of the value of the digital scale during the tensile test. The attachment force of H. diminuta is 0.021 ± 0.011 g. This method could be applied in studies of parasite biomechanics and the results may help medical device researchers to better mimic the unique functional morphology of this species of parasite.

Biodegradable airway stents in infants - Potential life-threatening pitfalls.

OBJECTIVE: The solution of severe tracheobronchial obstructions in early childhood means a great challenge. Biodegradable stents were intended to be a minimally invasive temporary solution which may decrease the number of interventions and limit the possible complications of stenting procedures. However, our first experiences have brought out a new, - especially in childhood - potentially life-threatening complication of this concept. METHODS: Five SX-ELLA biodegradable polydioxanone stents was applied in three patients because of severe tracheobronchial obstruction: congenital tracheomalacia (7 day-old), acquired tracheomalacia (10 month-old), and congenital trachea-bronchomalacia (10 month-old). RESULTS: The breathing of all children improved right after the procedure. We observed degradation of the stent from the 5th postoperative week which resulted in large intraluminar fragments causing significant airway obstruction: one patient died of severe pneumonia, the other baby required urgent bronchoscopy to remove the obstructing 'foreign body' from the trachea. In the third case repeated stent placements successfully maintained the tracheal lumen. CONCLUSIONS: Polydioxanone stents may offer an alternative to metallic or silastic stents for collapse or external compression of the trachea in children; however, large decaying fragments mean a potential risk especially in the small size pediatric airway. The fragmentation of the stent, which generally starts in the 4-6 postoperative weeks, may create large sharp pieces. These may be anchored to the mucosa and covered by crust leading to obstruction. As repeated interventions are required, we do not consider the application of biodegradable stents unambiguously advantageous.

Comparison of Nutrient and Metal Loadings with the Application of Swine Manure Slurries and Their Liquid Separates to Soils.

The accumulation of phosphorus (P) and metals is a serious concern with the continuous application of manure to agricultural soils. Solid-liquid separation of swine slurry is a promising approach to reduce P and metal loadings through application of separated liquid (SL) as a nutrient source. However, little information is available on nutrient and metal loadings with the application of SL compared with unseparated raw manure (RM). We analyzed element concentrations and calculated nutrient and metal loadings for RM and their respective SL applications, considering an application rate of 100 kg total nitrogen (N) ha. Samples of SL were obtained through three separation techniques: (i) centrifugation without a flocculant, (ii) centrifugation with a flocculant, and (iii) rotary press with a flocculant. Irrespective of separation technique, calculated P loadings with the application of SL were only 50 to 70% of that of RM at equivalent rates of total N yet exceeded crop removal rate. In contrast, calculated K and Na loadings with SL application were significantly greater than with RM, indicating a possible build-up of K and Na in soil. Calculated Ca and Mg loadings were significantly greater with RM than with SL. Loadings of Al, As, Ba, Cd, Cr, Fe, Mn, Ni, Pb, Sn, Se, Ti, and V were low, whereas Cu and Zn loadings were above crop removal rates for RM and SL. For solid-liquid separation to provide a lasting solution to the problem of P and metal accumulation, the SL must be supplemented with commercial N fertilizer to meet crop N demand.

Toward gene therapy for growth hormone deficiency via salivary gland expression of growth hormone.

OBJECTIVES: Salivary glands are useful targets for gene therapeutics. After gene transfer into salivary glands, regulated secretory pathway proteins, such as human growth hormone, are secreted into saliva, whereas constitutive secretory pathway proteins, such as erythropoietin, are secreted into the bloodstream. Secretion of human growth hormone (hGH) into the saliva is not therapeutically useful. In this study, we attempted to redirect the secretion of transgenic hGH from the saliva to the serum by site-directed mutagenesis. MATERIALS AND METHODS: We tested hGH mutants first in vitro with AtT20 cells, a model endocrine cell line that exhibits polarized secretion of regulated secretory pathway proteins. Selected mutants were further studied in vivo using adenoviral-mediated gene transfer to rat submandibular glands. RESULTS: We identified two mutants with differences in secretion behavior compared to wild-type hGH. One mutant, ΔN1-6 , was detected in the serum of transduced rats, demonstrating that expression of this mutant in the salivary gland resulted in its secretion through the constitutive secretory pathway. CONCLUSION: This study demonstrates that mutagenesis of therapeutic proteins normally destined for the regulated secretory pathway may result in their secretion via the constitutive secretory pathway into the circulation for potential therapeutic benefit.

Immunomodulatory and potential therapeutic role of mesenchymal stem cells in periodontitis.

Periodontitis is a chronic inflammatory disease leading to alveolar bone destruction, and eventually tooth loss. In genetically or environmentally predisposed individuals periodontopathogenic bacteria trigger an inflammatory immune response where activated macrophages secrete inflammatory cytokines and T helper 17 cells produce interleukin-17, receptor activator of nuclear factor kappa B ligand (RANKL) and tumor necrosis factor-α. Inflammation and the production of RANKL, the key cytokine responsible for osteoclast activation, cause excessive activation of osteoclasts. This results in a decoupling between bone formation and resorption, leading to bone loss. As conventional treatment does not target the inflammatory response and osteoclast activation, its effectiveness is limited. Novel treatments are thus required if we are to cure this disease. Mesenchymal stem cells (MSCs), including those of dental origin, are potent immunomodulators and are known to be suitable for tissue regeneration. MSCs can inhibit the immune response by suppressing T cells, inducing regulatory T cells and converting dendritic cells and macrophages into a regulatory phenotype. Additionally, genetic modulation may enhance the therapeutic potential of MSCs. In the present review the authors describe the potential use of MSCs, either unmodified or engineered for therapeutic purposes in periodontitis, with special emphasis on MSCs from dental pulp and periodontal ligament. The paper envisions that multiple targeting of this inflammatory disease by modulating the immune response, promoting bone regeneration and inhibiting bone resorption might yield significantly improved treatment outcomes when combined with conventional treatment modalities.

Lisis de adherencias epidurales (Parte 2). Técnica intervencionista / No disponible

La técnica lisis de adherencias epidurales se basa en la introducción de catéteres a través de agujas especiales con una técnica determinada para permitir colocar soluciones en lugares de difícil acceso, con el objeto de resolver cuadros crónicos de fibrosis o inflamación. Las soluciones como hialuronidasa y solución fisiológica hipertónica principalmente permiten provocar la lisis de las adherencias resultantes de la patología. Se desarrollan en esta publicación las distintas alternativas para aplicar correctamente la técnica en los distintos niveles de la columna vertebral. La técnica ha evolucionado desde la inyección a través de agujas de Tuhoy convencionales de soluciones con alguna propiedad neurolítica hasta las modernas agujas y catéteres con mapeo que permiten posicionar a distancia la solución deseada cerca de la raíz y/o el foramen indicados. Las dolencias y consultas médicas afectan más frecuentemente el segmento sacrolumbar pero las distintas entidades nosológicas, que derivan en tratamientos clínicos y quirúrgicos, pueden provocar dolor en el canal raquídeo, discos, estructuras vegetativas o en las raíces en cualquier segmento de la columna. Muchas de estas patologías especialmente después de tratamientos quirúrgicos provocan cuadros inflamatorios y adherencias epidurales, que evolucionan frecuentemente a cuadros de dolor crónico. Toda la fisiopatología e indicación de la presente técnica se desarrolla en la Parte 1 de esta publicación. En esta publicación describimos las técnicas para realizar las técnicas de lisis de adherencias a todos los niveles de la columna vertebral. Se explica minuciosamente la técnica caudal, lumbar, torácica y cervical, las soluciones que se administran, que catéteres en cada caso, la técnicas kinesiológicas de frotado neural y el mapeo epidural. Todas las técnicas explicadas son acompañadas al final de la publicación por una “Galería de Imágenes”. Se indica, el uso adecuado de las imágenes, las diferencias de volumen en cada caso, diagramas y posturas kinésicas recomendadas. Asimismo en cada caso se dan los tips para evitar las posibles complicaciones (AU)

This technique consists in the use of catheters and special needles to introduce solutions into difficult access sites in order to treat fibrosis or chronic inflammation conditions. Solutions such as hyaluronidase and hypertonic saline solution can be used for the lysis of adhesions caused by the pathology. This paper refers to different alternatives to correctly apply the technique at different spine levels. The technique has evolved from the conventional Tuhoy solution needles with some neurolitic properties to modern mapping needles and catheters that permit to position the desired solution at a distance, close to the desired root and/or foramen. The most frequently affected area is the sacrolumbar segment, but different nosological entities that require clinical or surgical treatments may cause pain in the spinal canal, discs, vegetative structures or roots in any spinal segment. Many of these pathologies, most particularly after surgical treatments, cause inflammatory conditions and epidural adhesions that frequently lead to chronic pain. The pathophysiology and indication of this technique is developed in Part 1 of this publication. This paper describes the techniques to perform lysis of adhesions at all spine levels. A thorough description is made of the caudal, lumbar, thoracic and cervical technique, the solutions administered, the catheters that are used in each case and physical therapy techniques for neural and epidural mapping. All techniques described are illustrated by an “Image gallery” for each procedure. The appropriate use of images is indicated with volume differences in each case. Tips for preventing complications are given (AU)

Lisis de adherencias epidurales (Parte 1). Fisiopatología y clínica / No disponible

Según estudios epidemiológicos toda la población tiene altas probabilidades de sufrir dolor lumbar en algún momento de su vida. Este cuadro suele ser reconocido como lumbalgia o lumbociática. En su forma clínica más común se observa mejoría rápida y solo presentan síntomas persistentes 5-10% de los casos (1). En la década de 1990 en EEUU, el sector salud registró costes estimados en miles de millones de dólares destinados al tratamiento del dolor lumbar, y teniendo en cuenta la tendencia a la búsqueda de una mayor expectativa de vida de la población, solo se puede esperar que los costes aumenten (2,3). El tratamiento comienza generalmente con medidas conservadoras, tales como medicación oral y terapia física, y puede incluir múltiples opciones intervencionistas invasivas para controlar el dolor. En ciertas ocasiones es necesario recurrir a cirugía para los pacientes que tienen déficit neurológico progresivo o para aquellos que están refractarios a otras terapéuticas. A veces el médico se encuentra frente a un dilema, después de una primera cirugía, con respecto a si se debería repetir la cirugía o intentar otra técnica alternativa. Este es el principal problema en el cual la liberación epidural de adherencias puede permitir "evitar cirugías". Se ha demostrado que esta técnica libera los nervios y disminuye la formación de cicatrices, lleva los anestésicos locales y los corticoides a sitios específicos y reduce el edema al usar hialuronidasa y solución salina hipertónica (15,16). La liberación epidural de adherencias ha demostrado eficacia para provocar reducción del dolor y de los síntomas neurológicos sin incurrir en los altos costes y el ocasionalmente largo periodo de recuperación que implica la repetición de la cirugía. En muchos casos previene la necesidad de una primera intervención quirúrgica (6,10). La liberación epidural de las adherencias ha sido calificada con un alto nivel de evidencia, que se correlaciona con un nivel de evidencia 1B o 1C para el síndrome post-cirugía lumbar, según las últimas guías basadas en la evidencia publicadas por la Asociación Americana de Médicos Intervencionistas especialistas en el Tratamiento del Dolor. Esto significa que la terapéutica se basa en estudios observacionales y en series de casos junto a ensayos randomizados y controlados. También según esta publicación se ha recomendado que esta terapéutica pueda aplicarse como primera indicación en muchas circunstancias en pacientes con dolor refractario (6-10). La técnica goza de un reconocimiento creciente en EE.UU. y en muchos otros países. Actualmente se le han asignado códigos conocidos como CPT (códigos de terminología de procedimiento) a los dos tipos de liberación de adherencias en EE.UU., CPT 62263 para tres inyecciones en el curso de 2-3 días, en general para pacientes hospitalizados, y CPT 62264 para las series de una sola inyección en el modelo de centro quirúrgico, que puede repetirse de 3 a 3,5 veces en un periodo de 12 meses. Pero lo mismo ocurre en España, Italia o Corea del Sur, entre otros. En la presente revisión se revisará la epidemiología, fisiopatología y las indicaciones hasta la preparación del paciente (AU)

Chances are relatively high that each of us will experience low back pain at some point in our lives. The usual course is rapid improvement with 5-10% developing persistent symptoms (1). In the 1990’s, the estimated cost of low back pain to the health industry was in the billions of dollars, and with a larger proportion of our population now reported to be older, this number can only be expected to increase (2,3). Treatment typically begins with conservative measures such as medication and physical therapy and may even include minimally and highly invasive pain management interventions. Surgery is sometimes required in patients who have progressive neurological deficits or those who have other therapies. A quandary sometimes arises, following a primary surgery, as to whether repeat surgery should be attempted or another alternative technique should be tried. This is the exact problem that the epidural adhesiolysis procedure was has a significant surgery sparing role that can help. It was shown to free up nerves and to break down scar formation, deliver site-specific corticosteroids and local anesthetics, and reduce edema with the use of hyaluronidase and hypertonic saline. Epidural adhesiolysis has afforded patients a reduction in pain and neurological symptoms without the expense and occasional long recovery period associated with repeat surgery, and often prevents the need for surgical intervention. This is the reason that Epidural Adhesiolysis was given an evidence rating of strong correlating to a 1B or 1C evidence level for Post-Lumbar Surgery Syndrome in the most recent American Society of Interventional Pain Physicians evidence-based guidelines. This suggests that the therapy is supported by observational studies and case series along with randomized-control trials. Recommendation was also made that this therapy could apply to most patients in most circumstances without reservations. Additionally CPT codes have been assigned to the two different kinds of adhesiolysis, CPT 62263 for the three times injections over 2-3 days, usually done as in patient hospital setting and CPT 62264 for the one time injection series surgery-center model that may need to be repeated 3 to 3.5 times in a 12 months period time. In this review we talk about from the patophisiology and epidemiology to indications and patient preparation (AU)

Differentiation potential of stem cells from human dental origin - promise for tissue engineering.

Recent studies have revealed the existence of stem cells in various human tissues including dental structures. We aimed to establish primary cell cultures from human dental pulp and periodontal ligament, to identify multipotential adult stem cells in these cultures, and to study the differentiation capacity of these cells to osteogenic and to neuronal fates. Dental pulp and the periodontal ligament were isolated from extracted human wisdom teeth. The extracellular matrix was enzymatically degraded to obtain isolated cells for culturing. Both dental pulp and periodontal ligament derived cultures showed high proliferative capacity and contained a cell population expressing the STRO-1 mesenchymal stem cell marker. Osteogenic induction by pharmacological stimulation resulted in mineralized differentiation as shown by Alizarin red staining in both cultures. When already described standard neurodifferentiation protocols were used, cultures exhibited only transient neurodifferentiation followed by either redifferentiation into a fibroblast-like phenotype or massive cell death. Our new three-step neurodifferentiation protocol consisting of (1) epigenetic reprogramming, then (2) simultaneous PKC/PKA activation, followed by (3) incubation in a neurotrophic medium resulted in robust neurodifferentiation in both pulp and periodontal ligament cultures shown by cell morphology, immunocytochemistry and real time PCR for vimentin and neuron-specific enolase. In conclusion, we report the isolation, culture and characterization of stem cell containing cultures from both human dental pulp and periodontal ligament. Furthermore, our data clearly show that both cultures differentiate into mineralized cells or to a neuronal fate in response to appropriate pharmacological stimuli. Therefore, these cells have high potential to serve as resources for tissue engineering not only for dental or bone reconstruction, but also for neuroregenerative treatments.

Vectorial bicarbonate transport by Par-C10 salivary cells.

Salivary glands produce a HCO(3)(-)-rich fluid that is important for the neutral milieu in the upper gastrointestinal tract. The molecular mechanism of this secretion is poorly understood. Par-C10, an immortalized rat parotid acinar line, has been shown to secrete Cl(-)- in response to Ca(2+-)-mobilizing stimuli. Our aim was to assess the capacity of polarized monolayers of Par-C10 cells to transport and secrete HCO(3)(-)-. Transepithelial electrolyte movement was evaluated by short-circuit current measurements. Intracellular pH (pH(i)) was measured by microfluorometry in cells loaded with BCECF. Monolayers of Par-C10 cells, grown on Transwell membranes, developed high transepithelial resistance and exhibited vectorial anion secretion which was activated by both ATP and forskolin. The currents were partially inhibited by bumetanide and by withdrawal of HCO(3)(-) indicating the dependence of ion movements on NKCC and on HCO(3)(-) ions, respectively. In HCO(3)(-)-free solutions the recovery of pH(i) from acid loading was abolished by EIPA. In the presence of HCO(3)(-) there was a strong EIPA-insensitive recovery from acid loading which was inhibited by H(2)DIDS. ATP and forskolin stimulated HCO(3)(-) efflux from the cells. Furthermore, HCl(-) withdrawal experiments showed the presence of DNDS-sensitive basolateral anion exchange. In conclusion Par-C10 cells achieve transepithelial transport that is sensitive to both intracellular Ca(2+)- and cAMP-dependent stimulation. We identified Na(+)/H(+) exchange, Na(+)-HCO(3)(-) cotransport and anion exchange at the basolateral side of the cells as being involved in intracellular pH regulation and vectorial HCO(3)(-) secretion. This cell line offers a good model for further studies to understand the molecular mechanisms of salivary HCO(3)(-) secretion.

Human submandibular gland (HSG) cell line as a model for studying salivary gland Ca2+ signalling mechanisms.

The human submandibular gland cell line (HSG) has been used as a model for studying the molecular mechanisms of salivary cells. The aim of this study was to investigate some aspects of salivary Ca2+ signalling. We focused on the presence and function of specific molecular markers of salivary cells to see whether this cell line retained normal salivary characteristics, despite the neoplastic changes. We detected the M3 acetylcholine receptor and intracellular salivary amylase mRNA with RT-PCR. Carbachol treatment caused a rapid, transient elevation of [Ca2+]i, showing that the cholinergic receptors are functional in HSG cells. Protein kinase C activation by phorbol-esther PMA, prior to carbachol treatment, inhibited the normal Ca2+ signalling pathway in HSG cells. Using selective antagonists, we also identified the dominant muscarinic receptor subtype M3 on HSG cells. We also observed that functional extracellular purinergic receptors were present on HSG cells and coupled to intracellular Ca2+ signalling. Our results suggested that the coupling mechanisms of these receptors remained relatively intact despite the neoplastic transformation. This enables us to use this cell line to model the role of muscarinic and purinergic control of salivary gland function, cell proliferation and differentiation.

Radiofrequency procedures.

Radiofrequency is a minimally invasive, target-selective technique that has been in clinical use for more than 25 years and has demonstrated success at reducing pain in several chronic pain conditions, including trigeminal neuralgia, chronic low back pain, postherpetic neuralgia, and complex regional pain syndrome. However, the success of radiofrequency in chronic pain has not been adequately reproduced in good-quality, randomized controlled trials, and its use in the management of neuropathic pain is under some debate. In addition, conventional radiofrequency occasionally leads to worsening and even new onset of neuropathic pain. Nevertheless, clinical experience suggests that radiofrequency may be a useful tool in the overall management of refractory neuropathic pain. Pulsed radiofrequency in particular is a minimally destructive procedure that may offer new opportunities and a broader perspective for therapy with radiofrequency.

Autonomic nerves terminating on microvessels in the pineal organs of various submammalian vertebrates.

In earlier works we have found that in the mammalian pineal organ, a part of autonomic nerves--generally thought to mediate light information from the retina--form vasomotor endings on smooth muscle cells of vessels. We supposed that they serve the vascular support for circadian and circannual periodic changes in the metabolic activity of the pineal tissue. In the present work, we investigated whether peripheral nerves present in the photoreceptive pineal organs of submammalians form similar terminals on microvessels. In the cyclostome, fish, amphibian, reptile and bird species investigated, autonomic nerves accompany vessels entering the arachnoidal capsule and interfollicular meningeal septa of the pineal organ. The autonomic nerves do not enter the pineal tissue proper but remain in the perivasal meningeal septa isolated by basal lamina. They are composed of unmyelinated and myelinated fibers and form terminals around arterioles, veins and capillaries. The terminals contain synaptic and granular vesicles. Comparing various vertebrates, more perivasal terminals were found in reptiles and birds than in the cyclostome, fish and amphibian pineal organs. Earlier, autonomic nerves of the pineal organs were predominantly investigated in connection with the innervation of pineal tissue. The perivasal terminals found in various submammalians show that a part of the pineal autonomic fibers are vasomotoric in nature, but the vasosensor function of some fibers cannot be excluded. We suppose that the vasomotor regulation of the pineal microvessels in the photosensory submamalian pineal--like in mammals--may serve the vascular support for circadian and circannual periodic changes in the metabolic activity of the pineal tissue. The higher number of perivasal terminals in reptiles and birds may correspond to the higher metabolic activity of the tissues in more differentiated species.

Laboratory characterization of phosphorus in fresh and oven-dried organic amendments.

This study was performed to determine the forms of P and to examine the influence of oven-drying on P forms in different organic amendments. Samples of biosolids, beef and dairy cattle manures, and hog manures from sow and nursery barns were used in this study. Both fresh and oven-dried amendments were analyzed for inorganic (Pi), organic (Po), and total phosphorus using a modified Hedley fractionation technique. Water extracted about 10% of total biosolids P and 30 to 40% of total hog and cattle manure P. The amount of P extracted by NaHCO3 ranged from 21 to 32% of total P in all organic amendments except in the dairy cattle manure with 45% of total P. The labile P fraction (sum of H2O- and NaHCO3-extractable P) was 24% of biosolids P, 60% of hog manure P, and 70% of dairy cattle manure P. The residual P was about 10% in biosolids and cattle manures and 5 to 8% in hog manures. Oven-drying caused a transformation in forms of P in the organic amendments. In hog manures, H2O-extractable Po was transformed to Pi, while in the dairy manure NaHCO3-extractable P was converted to H2O-extractable Pi with oven-drying. Therefore, caution should be exercised in using oven-drying for studies that evaluate forms of P in organic amendments. Overall, these results indicate that biosolids P may be less susceptible to loss by water when added to agricultural land.

Distribution of aquaporin water channels AQP1 and AQP5 in the ductal system of the human pancreas.

BACKGROUND: The exocrine pancreas secretes large volumes of isotonic fluid, most of which originates from the ductal system. The role of aquaporin (AQP) water channels in this process is unknown. METHODS: Expression and localisation of known AQP isoforms was examined in normal human pancreas, pancreatic adenocarcinoma, and pancreatic cell lines of ductal origin (Capan-1, Capan-2, and HPAF) using reverse transcriptase-polymerase chain reaction and immunohistochemistry. RESULTS: Messenger RNAs for AQP1, -3, -4, -5, and -8 were detected in normal pancreas and in pancreatic adenocarcinoma. The cell lines expressed AQP3, -4, and -5 but lacked AQP1 and AQP8. Immunohistochemistry of normal pancreas revealed that AQP1 is strongly expressed in centroacinar cells and in both the apical and basolateral domains of intercalated and intralobular duct epithelia. AQP1 expression declined with distance along the small interlobular ducts and was not detectable in larger interlobular ducts. AQP3 and AQP4 were not detectable by immunohistochemistry. AQP5 was observed at the apical membrane of intercalated duct cells and also in duct associated mucoid glands. AQP8 was confined to the apical pole of acinar cells. Both AQP1 and AQP5 were colocalised with cystic fibrosis transmembrane conductance regulator (CFTR) at the apical membrane of intercalated duct cells. CONCLUSIONS: AQP1 and AQP5 are strongly expressed in the intercalated ducts of the human pancreas. Their distribution correlates closely with that of CFTR, a marker of ductal electrolyte secretion. This suggests that fluid secretion is concentrated in the terminal branches of the ductal tree and that both AQP1 and AQP5 may play a significant role.

Pro-apoptotic and anti-apoptotic molecules affecting pathways of signal transduction.

Selective inhibition of the "false" proliferative signals via targeting tyrosine kinases resulting in the induction of apoptosis by depletion of the "survival factors" is one of the most studied and widely accepted concepts of modern chemotherapy. We have synthesized a series of potent tyrosine kinase inhibitors and tested these compounds for apoptosis induction. Some of the tyrosine kinase inhibitors caused either apoptotic or cytoplasmic vacuolar cell death in various tumor cell cultures. The somatostatin analogue oligopeptide TT-232, which indirectly inhibits tyrosine kinases, exerted a dose-dependent apoptosis-inducing effect. The tumor growth-inhibitory effect of TT-232 and some tyrosine kinase inhibitors has also been proven by in vivo experiments, using human tumor xenografts. On the other hand, a dose-dependent pro- or anti-apoptotic activity of (-)-deprenyl has been shown in melanoma cell cultures, the lower doses inhibiting and the higher doses inducing apoptosis. Various metabolites of (-)-deprenyl are responsible for these actions. The effect of (-)-deprenyl is connected with depolarization of mitochondrial membranes. The kinase inhibitors act on the growth factor receptor signaling pathways (survival factor pathways) and initiate the caspase cascade. The key enzyme for the action of both pro-apoptotic and anti-apoptotic compounds is caspase 3.

Extracellular calcium sensing receptor in human pancreatic cells.

BACKGROUND AND AIMS: The extracellular calcium sensing receptor (CaR) plays a key role in the calcium homeostatic system and is therefore widely expressed in tissues involved in calcium metabolism. However, the CaR has also been identified in other tissues where its role is less clear. We have investigated the presence of the CaR in the human pancreas. METHODS: Messenger RNA for the CaR was detected by reverse transcription-polymerase chain reaction and the protein was localised by immunostaining. CaR function was assayed in Capan-1 cells by measuring intracellular calcium and [(3)H] thymidine incorporation. RESULTS: The receptor was highly expressed in human pancreatic ducts. It was also expressed in exocrine acinar cells, in islets of Langerhans, and in intrapancreatic nerves and blood vessels. The CaR was expressed in both normal and neoplastic human tissue samples but was detected in only one of five ductal adenocarcinoma cells lines examined. Experiments on the CaR expressing adenocarcinoma cell line Capan-1 showed that the CaR was functional and was linked to mobilisation of intracellular calcium. Stimulation of the CaR reduced Capan-1 cell proliferation. CONCLUSIONS: We propose that the CaR may play multiple functional roles in the human pancreas. In particular, the CaR on the duct luminal membrane may monitor and regulate the Ca(2+) concentration in pancreatic juice by triggering ductal electrolyte and fluid secretion. This could help to prevent precipitation of calcium salts in the duct lumen. The CaR may also help to regulate the proliferation of pancreatic ductal cells.

Technical aspects of radiofrequency.

Radiofrequency (RF) is an alternating electric field with an oscillating frequency of 500,000 Hz. If the resulting current flows through a percutaneously introduced electrode, heat will be produced around the electrode because the body tissue acts as a resistor. RF can, therefore, be used to ablate nervous tissue in the treatment of chronic pain. This method has gained acceptance for percutaneous cordotomy and for the treatment of trigeminal neuralgia. For spinal pain, the method had little success initially, but since the introduction of small diameter instrumentation, the results have markedly improved. he mechanism of action of RF has not been challenged until recently even though there was awareness that some observations were not consistent with the heat concept. The formation of heat is not the only occurrence during RF treatment, however. The tissue surrounding the electrode is also exposed to the RF electric field. This exposure has a biological effect as has been demonstrated both in cells in a cell culture and in the exposure to RF of dorsal root ganglia, resulting in transsynaptal induction of early gene expression in the dorsal horn. The mode of action of RF is, therefore, uncertain at the moment. The method of pulsed RF is based on the concept that the production of heat has been a by-product of RF treatment and that the clinical effect is due to exposure to the electric field. In pulsed RF, the generator output is interrupted to allow for the elimination of heat in the silent period. The early results have been encouraging, but the results of controlled, prospective studies are not yet available. Since there are now 2 almost diametrically opposed views on the mode of action of RF, it is difficult to give recommendations for treatment. The decision is easy for indications for which heat RF has traditionally been contraindicated such as the treatment of peripheral nerves and trigger points. When the application of heat carries a potential risk, for instance if the dorsal root ganglion is the target structure, the use of pulsed RF is also recommended. As for the medial branch the situation is controversial. Since there are controlled studies available showing the effect of heat lesions, it is recommended that the technique should not be changed until further studies have been completed. Finally, the equipment for RF treatment is described and safety issues are discussed.

Different affinity states of CCK(1) receptors on pancreatic acini and gastric smooth muscle in the rat.

It has recently been shown that--after chronic cholecystokinin (CCK) treatment--an adaptation of pancreatic secretory but not gastric motor function does occur. Recent studies indicate that the CCK(1)-receptor exists in two (i.e. high and low) affinity states, which could be distinguished by the CCK-analogue JMV-180. CCK occupancy of high and low affinity sites is thought to be related to the initiation of different intracellular events and consequent biological responses. Affinity states of CCK(1)-receptors on pancreas and gastrointestinal (GI) smooth muscle could be different and this can offer an explanation for the different effects of CCK on pancreatic and gastric growth. We therefore studied the affinity states of CCK(1)-receptors on isolated rat pancreatic acini and gastric smooth muscle preparations. When acini were incubated with increasing concentrations of CCK-8, a biphasic (i.e. stimulation followed by inhibition) effect on amylase release was observed. JMV-180 caused only stimulation of enzyme release and combined JMV-180 and CCK stimulation (at submaximal doses) resulted in an additive secretory response. CCK-8 induced contractions of pyloric, antral and fundic muscle in a concentration-dependent manner. The response was monophasic, reaching a plateau. JMV-180 had only a very weak effect on these preparations. On the contrary, it inhibited CCK-induced contractions in a competitive manner, the concentration-response curve to CCK being shifted to the right by the CCK analogue. Our data suggest that the affinity states of CCK(1)-receptors on rat pancreatic and gastric tissue are different. On pancreatic acini CCK(1)-receptors exist in both high- and low-affinity states whose occupation is followed by the sequence of intracellular events leading to growth. In contrast, occupation of low affinity receptors (the only ones present in the GI smooth muscle) does not lead to cell proliferation. This difference therefore explains the different adaptive response of the pancreas and the stomach to chronic CCK administration. Furthermore, different affinity states of CCK(1)-receptors may mediate different functions of the digestive tract.

Effects of putative galanin antagonists M35 and C7 on rat exocrine pancreas.

Galanin is a neuropeptide having a wide range of biological actions. Recently selective galanin receptor antagonists such as M35 [galanin(1-12)-Pro-bradykinin(2-9)-amide] and C7 [galanin(1-12)-Pro-spantide-amide] have been described. These antagonists have blocked the actions of galanin on flexor reflex, glucose-induced insulin secretion, and acetyicholine release from hippocampus. Our present aim was to investigate whether M35 and C7 can affect galanin-induced inhibition of pancreatic enzyme secretion in rats. Pancreatic enzyme secretion was studied in urethane-anesthetized rats supplied with jugular vein catheter and pancreatic cannula. Amylase secretion evoked by submaximal CCK-8 stimulation was inhibited dose-dependently by galanin in anesthetized rats. Surprisingly, neither M35 nor C7 was able to inhibit the responses of the exocrine pancreas to galanin. However, both putative galanin receptor antagonists behaved as agonists in our experimental models. Our data suggest that the effects of galanin on pancreatic enzyme secretion are not mediated by M35- or C7-sensitive galanin receptors. Therefore, these galanin receptors are different from those described in the central nervous system.