We sought to compare a 2-day quadruple therapy with a 14-day triple therapy in the treatment of H... more We sought to compare a 2-day quadruple therapy with a 14-day triple therapy in the treatment of Helicobacter pylori infection. Eighty-one consecutive patients with an endoscopically diagnosed peptic ulcer and demonstrated infection by H. pylori were included in the study. Patients were randomized to receive omeprazole 40 mg b.i.d., amoxicillin 2.5 g once daily, metronidazole 500 mg t.i.d., and bismuth subcitrate 360 mg t.i.d. for 2 days, followed by omeprazole 20 mg once daily for 6 additional days (Group 1) or a 14-day course of omeprazole 20 mg b.i.d., amoxicillin 1 g t.i.d., and metronidazole 500 mg t.i.d. (Group 2). Eradication was evaluated by antral biopsy and rapid urease test at 2 months after therapy and by C13-urea breath test after a year. Two patients were lost to follow-up at 2 months. Intention-to-treat analysis showed that H. pylori infection was cured in 29 of 42 patients (69%; 95% CI: 53-82%) in Group 1 versus 36 of 39 (92%; 95% CI: 78-98%) of patients in Group 2 (p = 0.009). Per-protocol analysis showed a cure rate of 71% (95% CI: 55-84%) (29/41 patients) and 95% (95% CI: 81-99%) (36/38 patients), respectively (p = 0.007). Fifty-five of 65 cured patients returned 1 year after treatment (26 in Group 1, 29 in Group 2). All but one in Group 2 remained cured. There were no significant differences in compliance (88% in Group 1 versus 92% in Group 2) or in the presence of side effects (27%; 95% CI: 15-43% versus 41%; 95% CI: 26-58%; ns). Two-day quadruple therapy is significantly less effective than 2-wk triple treatment.
European Journal of Gastroenterology & Hepatology, 2000
To test the usefulness of a twice-a-day, simplified quadruple therapy to cure Helicobacter pylori... more To test the usefulness of a twice-a-day, simplified quadruple therapy to cure Helicobacter pylori infection. Helicobacter pylori-positive ulcer patients were treated with omeprazole 20 mg twice a day (b.d.), amoxicillin 1 g b.d., tinidazole 500 mg b.d. and bismuth subcitrate 240 mg b.d. for 7 days in an experimental, noncomparative pilot study. The gastroenterology unit of a county hospital. Forty-four consecutive patients with peptic ulcer disease and H. pylori infection. Cure was tested by either endoscopy or breath test after 2 months, and by urea breath test 6 months after therapy. One patient was lost to follow-up. Of the remaining 43, 37 were cured at the first control, giving an intention-to-treat cure rate of 84.1% (95% CI 69-93%) and a per protocol cure rate of 86% (95% CI 71-94%). Thirty-three cured patients agreed to return for a six-month breath test. All but one were cured (long-term per protocol cure rate 82.1%; 95% CI 66-92%). This particular quadruple therapy is well tolerated and easy to comply with. However, cure rates did not reach 90%.
Neurotrophins and their receptors, the trk receptor tyrosine kinases (trks) and p75NTR, are diffe... more Neurotrophins and their receptors, the trk receptor tyrosine kinases (trks) and p75NTR, are differentially expressed among the cell types that make up synapses. It is important to determine the precise location of these molecules involved in neurotransmission. Here we use immunostaining and Western blotting to study the localization and expression of neurotrophin brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) and the receptors tropomyosin-related kinase b (trkB) and p75NTR at the adult neuromuscular junction. Our confocal immunofluorescence results on the whole mounts of the mouse Levator auris longus muscle and on semithin cross-sections showed that BDNF, NT-4, trkB, and p75NTR were localized on the three cells in the neuromuscular synapse (motor axons, post-synaptic muscle and Schwann cells).
We use immunocytochemistry to show that neurotrophin-4 (NT-4) and its receptor proteins (p75(NTR)... more We use immunocytochemistry to show that neurotrophin-4 (NT-4) and its receptor proteins (p75(NTR) and tropomyosin-related tyrosine kinase B) are present in neonatal neuromuscular junctions (NMJ) colocalized with several synaptic markers. NT-4 incubation (1h, in the range 2-12 nM) does not change the size of the endplate potential between P6 and P45. However, extended exposure (3h) to a relatively low dose of NT-4 (2 nM) potentiates ACh release (approx. 70%) in adult but not in neonatal muscles. The present results suggest that the developmental mechanism of axonal competition and neonatal elimination of redundant synapses cannot be modulated by added NT-4. However, this neurotrophin was able to modulate synaptic transmission locally in the adult NMJ.
In this study, we used a monoclonal IgM antibody from a patient with a pure motor chronic demyeli... more In this study, we used a monoclonal IgM antibody from a patient with a pure motor chronic demyelinating polyneuropathy, which binds specifically to the complex gangliosides GM2, GalNAc-GD1a, and GalNAc-GM1b, which appear to have a common epitope of -[GalNAcβ1-4Gal(3-2αNeuAc)β1]. This was done for the following reasons: (1) to localize these gangliosides in specific cellular components of the neuromuscular junction (NMJ), and (2) to describe the anti–ganglioside antibody–induced structural and functional changes in the NMJs to gain insight into the role of gangliosides in the synaptic function. Using immunofluorescence techniques, we found that these gangliosides are located only in the presynaptic component of the motor end-plates, both in nerve terminals and in Schwann cells. After 2 weeks of continued passive transfer of the IgM monoclonal antibody over the mouse levator auris longus muscle, electromyography showed an axonal or NMJ disorder. Morphology showed important nerve terminal growth and retraction changes. Using intracellular recording electrophysiology, we found neurotransmitter release alterations, including quantal content reduction and an immature expression of voltage-dependent calcium channels similar to what occurred during NMJ development and regeneration. These changes were complement independent. The results showed that these gangliosides were involved in the reciprocal Schwann cell–nerve terminal interactions, including structural stability and neurotransmission. Ann Neurol 2005;57:396–407
Confocal immunohistochemistry shows that neurotrophin-3 (NT-3) and its receptor tropomyosin-relat... more Confocal immunohistochemistry shows that neurotrophin-3 (NT-3) and its receptor tropomyosin-related tyrosin kinase C (trkC) are present in both neonatal (P6) and adult (P45) mouse motor nerve terminals in neuromuscular junctions (NMJ) colocalized with several synaptic proteins. NT-3 incubation (1-3h, in the range 10-200ng/ml) does not change the size of the evoked and spontaneous endplate potentials at P45. However, NT-3 (1h, 100ng/ml) strongly potentiates evoked ACh release from the weak (70%) and the strong (50%) axonal inputs on dually innervated postnatal endplates (P6) but not in the most developed postnatal singly innervated synapses at P6. The present results indicate that NT-3 has a role in the developmental mechanism that eliminates redundant synapses though it cannot modulate synaptic transmission locally as the NMJ matures.
Individual skeletal muscle fibers in most new-born rodents are innervated at a single endplate by... more Individual skeletal muscle fibers in most new-born rodents are innervated at a single endplate by several motor axons. During the first postnatal weeks, the polyneuronal innervation decreases in a process of synaptic elimination. Previous studies showed that the naturally occurring serine-protease thrombin mediates the activity-dependent synapse reduction at the neuromuscular junction (NMJ) in vitro and that thrombin-receptor activation may modulate nerve terminal consolidation through a protein kinase mechanism. To test whether these mechanisms may be operating in vivo, we applied external thrombin and its inhibitor hirudin, and several substances affecting the G protein-protein kinase C system (GP-PKC) directly over the external surface of the neonatal rat Levator auris longus muscle. Muscles were processed for immunocytochemistry to simultaneously detect acetylcholine receptors (AChRs) and axons for counting the percentage of polyinnervated NMJ. We found that exogenous thrombin accelerated synapse loss and hirudin blocked axonal removal. Phorbol-12-myristate-13-acetate, a potent PKC activator, had a similar effect as thrombin, whereas the PKC inhibitors, calphostin C and staurosporine, prevented axonal removal. Pertussis toxin, an effective blocker of GP function, blocked synapse elimination. These findings suggest that the normal synapse elimination in the neonatal rat muscle may be modulated, at least in part, by the pertussis-sensitive G-protein and PKC activity and that thrombin could play a role in the postnatal synaptic maturation in vivo.
We have used intracellular recording to investigate the existence of a functional link between mu... more We have used intracellular recording to investigate the existence of a functional link between muscarinic presynaptic acetylcholine (ACh) autoreceptors, the intracellular serine-threonine kinases-mediated transduction pathways and transmitter release in the motor nerve terminals of adult rats. We found the following. (1) Transmitter release was reduced by the M1 muscarinic acetylcholine receptor (mAChR) blocker pirenzepine and enhanced by the M2 blocker methoctramine. The unselective mAChR blocker atropine increased ACh release, which suggests the unmasking of another parallel release-potentiating mechanism. There are therefore two opposite, though finely balanced, M1–M2 mAChR-operated mechanisms that tonically modulate transmitter release. (2) Both M1 and M2 mechanisms were altered when protein kinase C (PKC), protein kinase A (PKA) or the P/Q-type calcium channel were blocked. (3) Both PKC and PKA potentiated release when they were specifically stimulated [with phorbol 12-myristate 13-actetate (PMA) and Sp-8-Br cAMPs, respectively], and both needed the P/Q channel. (4) In normal conditions PKC seemed not to be directly involved in transmitter release (the PKC blocker calphostin C did not reduce release), whereas PKA was coupled to potentiate release (the PKA blocker H-89 reduced release). However, when an imbalance of the M1–M2 mAChRs function was experimentally produced with selective blockers, an inversion of the kinase function occurred and PKC could then stimulate transmitter release, whereas PKA was uncoupled. (5) The muscarinic function may be explained by the existence of an M1-mediated increased PKC activity-dependent potentiation of release and an M2-mediated PKA decreased activity-dependent release reduction.These findings show that there is a precise interrelation pattern of the mAChRs, PKC and PKA in the control of the neurotransmitter release.
We sought to compare a 2-day quadruple therapy with a 14-day triple therapy in the treatment of H... more We sought to compare a 2-day quadruple therapy with a 14-day triple therapy in the treatment of Helicobacter pylori infection. Eighty-one consecutive patients with an endoscopically diagnosed peptic ulcer and demonstrated infection by H. pylori were included in the study. Patients were randomized to receive omeprazole 40 mg b.i.d., amoxicillin 2.5 g once daily, metronidazole 500 mg t.i.d., and bismuth subcitrate 360 mg t.i.d. for 2 days, followed by omeprazole 20 mg once daily for 6 additional days (Group 1) or a 14-day course of omeprazole 20 mg b.i.d., amoxicillin 1 g t.i.d., and metronidazole 500 mg t.i.d. (Group 2). Eradication was evaluated by antral biopsy and rapid urease test at 2 months after therapy and by C13-urea breath test after a year. Two patients were lost to follow-up at 2 months. Intention-to-treat analysis showed that H. pylori infection was cured in 29 of 42 patients (69%; 95% CI: 53-82%) in Group 1 versus 36 of 39 (92%; 95% CI: 78-98%) of patients in Group 2 (p = 0.009). Per-protocol analysis showed a cure rate of 71% (95% CI: 55-84%) (29/41 patients) and 95% (95% CI: 81-99%) (36/38 patients), respectively (p = 0.007). Fifty-five of 65 cured patients returned 1 year after treatment (26 in Group 1, 29 in Group 2). All but one in Group 2 remained cured. There were no significant differences in compliance (88% in Group 1 versus 92% in Group 2) or in the presence of side effects (27%; 95% CI: 15-43% versus 41%; 95% CI: 26-58%; ns). Two-day quadruple therapy is significantly less effective than 2-wk triple treatment.
European Journal of Gastroenterology & Hepatology, 2000
To test the usefulness of a twice-a-day, simplified quadruple therapy to cure Helicobacter pylori... more To test the usefulness of a twice-a-day, simplified quadruple therapy to cure Helicobacter pylori infection. Helicobacter pylori-positive ulcer patients were treated with omeprazole 20 mg twice a day (b.d.), amoxicillin 1 g b.d., tinidazole 500 mg b.d. and bismuth subcitrate 240 mg b.d. for 7 days in an experimental, noncomparative pilot study. The gastroenterology unit of a county hospital. Forty-four consecutive patients with peptic ulcer disease and H. pylori infection. Cure was tested by either endoscopy or breath test after 2 months, and by urea breath test 6 months after therapy. One patient was lost to follow-up. Of the remaining 43, 37 were cured at the first control, giving an intention-to-treat cure rate of 84.1% (95% CI 69-93%) and a per protocol cure rate of 86% (95% CI 71-94%). Thirty-three cured patients agreed to return for a six-month breath test. All but one were cured (long-term per protocol cure rate 82.1%; 95% CI 66-92%). This particular quadruple therapy is well tolerated and easy to comply with. However, cure rates did not reach 90%.
Neurotrophins and their receptors, the trk receptor tyrosine kinases (trks) and p75NTR, are diffe... more Neurotrophins and their receptors, the trk receptor tyrosine kinases (trks) and p75NTR, are differentially expressed among the cell types that make up synapses. It is important to determine the precise location of these molecules involved in neurotransmission. Here we use immunostaining and Western blotting to study the localization and expression of neurotrophin brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) and the receptors tropomyosin-related kinase b (trkB) and p75NTR at the adult neuromuscular junction. Our confocal immunofluorescence results on the whole mounts of the mouse Levator auris longus muscle and on semithin cross-sections showed that BDNF, NT-4, trkB, and p75NTR were localized on the three cells in the neuromuscular synapse (motor axons, post-synaptic muscle and Schwann cells).
We use immunocytochemistry to show that neurotrophin-4 (NT-4) and its receptor proteins (p75(NTR)... more We use immunocytochemistry to show that neurotrophin-4 (NT-4) and its receptor proteins (p75(NTR) and tropomyosin-related tyrosine kinase B) are present in neonatal neuromuscular junctions (NMJ) colocalized with several synaptic markers. NT-4 incubation (1h, in the range 2-12 nM) does not change the size of the endplate potential between P6 and P45. However, extended exposure (3h) to a relatively low dose of NT-4 (2 nM) potentiates ACh release (approx. 70%) in adult but not in neonatal muscles. The present results suggest that the developmental mechanism of axonal competition and neonatal elimination of redundant synapses cannot be modulated by added NT-4. However, this neurotrophin was able to modulate synaptic transmission locally in the adult NMJ.
In this study, we used a monoclonal IgM antibody from a patient with a pure motor chronic demyeli... more In this study, we used a monoclonal IgM antibody from a patient with a pure motor chronic demyelinating polyneuropathy, which binds specifically to the complex gangliosides GM2, GalNAc-GD1a, and GalNAc-GM1b, which appear to have a common epitope of -[GalNAcβ1-4Gal(3-2αNeuAc)β1]. This was done for the following reasons: (1) to localize these gangliosides in specific cellular components of the neuromuscular junction (NMJ), and (2) to describe the anti–ganglioside antibody–induced structural and functional changes in the NMJs to gain insight into the role of gangliosides in the synaptic function. Using immunofluorescence techniques, we found that these gangliosides are located only in the presynaptic component of the motor end-plates, both in nerve terminals and in Schwann cells. After 2 weeks of continued passive transfer of the IgM monoclonal antibody over the mouse levator auris longus muscle, electromyography showed an axonal or NMJ disorder. Morphology showed important nerve terminal growth and retraction changes. Using intracellular recording electrophysiology, we found neurotransmitter release alterations, including quantal content reduction and an immature expression of voltage-dependent calcium channels similar to what occurred during NMJ development and regeneration. These changes were complement independent. The results showed that these gangliosides were involved in the reciprocal Schwann cell–nerve terminal interactions, including structural stability and neurotransmission. Ann Neurol 2005;57:396–407
Confocal immunohistochemistry shows that neurotrophin-3 (NT-3) and its receptor tropomyosin-relat... more Confocal immunohistochemistry shows that neurotrophin-3 (NT-3) and its receptor tropomyosin-related tyrosin kinase C (trkC) are present in both neonatal (P6) and adult (P45) mouse motor nerve terminals in neuromuscular junctions (NMJ) colocalized with several synaptic proteins. NT-3 incubation (1-3h, in the range 10-200ng/ml) does not change the size of the evoked and spontaneous endplate potentials at P45. However, NT-3 (1h, 100ng/ml) strongly potentiates evoked ACh release from the weak (70%) and the strong (50%) axonal inputs on dually innervated postnatal endplates (P6) but not in the most developed postnatal singly innervated synapses at P6. The present results indicate that NT-3 has a role in the developmental mechanism that eliminates redundant synapses though it cannot modulate synaptic transmission locally as the NMJ matures.
Individual skeletal muscle fibers in most new-born rodents are innervated at a single endplate by... more Individual skeletal muscle fibers in most new-born rodents are innervated at a single endplate by several motor axons. During the first postnatal weeks, the polyneuronal innervation decreases in a process of synaptic elimination. Previous studies showed that the naturally occurring serine-protease thrombin mediates the activity-dependent synapse reduction at the neuromuscular junction (NMJ) in vitro and that thrombin-receptor activation may modulate nerve terminal consolidation through a protein kinase mechanism. To test whether these mechanisms may be operating in vivo, we applied external thrombin and its inhibitor hirudin, and several substances affecting the G protein-protein kinase C system (GP-PKC) directly over the external surface of the neonatal rat Levator auris longus muscle. Muscles were processed for immunocytochemistry to simultaneously detect acetylcholine receptors (AChRs) and axons for counting the percentage of polyinnervated NMJ. We found that exogenous thrombin accelerated synapse loss and hirudin blocked axonal removal. Phorbol-12-myristate-13-acetate, a potent PKC activator, had a similar effect as thrombin, whereas the PKC inhibitors, calphostin C and staurosporine, prevented axonal removal. Pertussis toxin, an effective blocker of GP function, blocked synapse elimination. These findings suggest that the normal synapse elimination in the neonatal rat muscle may be modulated, at least in part, by the pertussis-sensitive G-protein and PKC activity and that thrombin could play a role in the postnatal synaptic maturation in vivo.
We have used intracellular recording to investigate the existence of a functional link between mu... more We have used intracellular recording to investigate the existence of a functional link between muscarinic presynaptic acetylcholine (ACh) autoreceptors, the intracellular serine-threonine kinases-mediated transduction pathways and transmitter release in the motor nerve terminals of adult rats. We found the following. (1) Transmitter release was reduced by the M1 muscarinic acetylcholine receptor (mAChR) blocker pirenzepine and enhanced by the M2 blocker methoctramine. The unselective mAChR blocker atropine increased ACh release, which suggests the unmasking of another parallel release-potentiating mechanism. There are therefore two opposite, though finely balanced, M1–M2 mAChR-operated mechanisms that tonically modulate transmitter release. (2) Both M1 and M2 mechanisms were altered when protein kinase C (PKC), protein kinase A (PKA) or the P/Q-type calcium channel were blocked. (3) Both PKC and PKA potentiated release when they were specifically stimulated [with phorbol 12-myristate 13-actetate (PMA) and Sp-8-Br cAMPs, respectively], and both needed the P/Q channel. (4) In normal conditions PKC seemed not to be directly involved in transmitter release (the PKC blocker calphostin C did not reduce release), whereas PKA was coupled to potentiate release (the PKA blocker H-89 reduced release). However, when an imbalance of the M1–M2 mAChRs function was experimentally produced with selective blockers, an inversion of the kinase function occurred and PKC could then stimulate transmitter release, whereas PKA was uncoupled. (5) The muscarinic function may be explained by the existence of an M1-mediated increased PKC activity-dependent potentiation of release and an M2-mediated PKA decreased activity-dependent release reduction.These findings show that there is a precise interrelation pattern of the mAChRs, PKC and PKA in the control of the neurotransmitter release.
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