No abstract available.
Humans* ; Metalloproteases ; Prostate* ; Prostatic Neoplasms

Medial vestibular nucleus (MVN) neurons are found to have spontaneous electrical activity in the absence of any detectable synaptic input. To investigate the contributions of intrinsic mechanisms to the spontaneous activity of type B MVN neurons, we examined the effects of various channel blockers on spontaneous firing by means of patch clamp recordings. Coronal slice (400 micrometer) of the vestibular nucleus region was sequentially treated with pronase 0.2 mg/ml and thermolysin 0.2 mg/ml, then single neurons were mechanically dissociated. MVN neurons recorded in neonatal rat were shown to have either a single deep afterhyperpolarization (AHP; type A cells), or an early fast and a delayed slow AHP (type B cells). In 300 nM TTX, spontaneous firing was blocked in type B cells tested. In 8 of 11 cells, underlying fluctuation or oscillations in membrane potential was not remained, and hyperpolarization did not produce rebound low-threshold calcium spikes. Although type B MVN neurons possessed hyperpolarization activated cation current (Ih), cesium had no effect on firing rates. The spike AHP is calcium dependent. When Ca2+ influx was blocked in external Ca2+ free solution, repetitive firing was abolished and the cell rested at depolarized membrane potentials. Application of apamin (300 nM) caused a profound reduction in the amplitude of the AHP and produced rhythmic burst firing. These findings suggest that the spontaneous activity of type B MVN neurons is regulated by interactions between the membrane depolarization mainly due to a persistent sodium conductances and hyperpolarization due to the calcium-activated potassium conductances.
Animals ; Apamin ; B-Lymphocytes ; Calcium ; Calcium Signaling ; Cesium ; Fires* ; Membrane Potentials ; Membranes ; Neurons* ; Potassium ; Pronase ; Rats ; Sodium ; Thermolysin ; Vestibular Nuclei*

pronase 0.2mg/ml and thermolysin 0.2mg/ml, then single neurons were mechanically dissociated.Voltage-dependent sodium currents showed that the half-maximum activation potential was -41.8 +/- 1.8mV and half-maximum inactivation potential was -62.4 +/- 3.0mV.And the currents were blocked totally by application of 100nM tetrodotoxin.In a Ca2+ free solution,low-threshold transient (IA )and high-threshold sustained (IK )currents were recorded.The half-maximum activation and inactivation potential of IK were 2.5 +/- 1.9mV and -37.1 +/- 2.3mV,respectively.IA was activated and inactivated more rapidly than IK. The half-maximum acti-vation and inactivation potential were -21.6 +/- 6.3mV and -84.5 +/- 5.0mV,respectively. When a 4-aminopy-ridine of 5mM was applied, IA was almost totally blocked. These results reveal that MDH neurons express a variety of voltage-dependent ionic currents with distinct physiological and pharmacological properties,and they play an essential role in the transmission and modulation of sensation, especially pain, from trigeminal region.]]>
Animals ; Horns ; Myelin Sheath ; Neurons ; Patch-Clamp Techniques ; Potassium ; Pronase ; Rats ; Sensation ; Sodium ; Thermolysin ; Trigeminal Nucleus, Spinal

Intimal hyperplasia is a feature of the normal adaptive response of vessels to hemodynamic stresses, as well as being a characteristic of vessel injuries that are healing. Intimal hyperplasia in the region of endarterectomy, balloon angioplasty and vascular bypass graft anastomosis is a major cause of the long-term failure of vascular reconstruction. The underlying causes of intimal hyperplasia are proliferation and migration of vascular smooth muscle cells, and this is all provoked by injury, inflammation and mechanical stretch. This review discusses both the final common pathways that lead to smooth muscle cell migration and proliferation and their patho-physiological triggers. In this review, we have critically evaluated and summarized the literature to understand and interlink the numerous established and emerging factors that play key roles in the development of intimal hyperplasia.
Angioplasty, Balloon ; Endarterectomy ; Glycosaminoglycans ; Hemodynamics ; Hyperplasia ; Inflammation ; Metalloproteases ; Muscle, Smooth, Vascular ; Myocytes, Smooth Muscle ; Transplants

BACKGROUND: One of the most important steps in neoplastic progression is represented by invasion of surrounding normal tissues by neoplastic cells. Enzymes such as the metalloproteinases(MMPs) are thought to be involved in the process of destruction of basement membranes and stromal invasion by tumor cells. OBJECTIVE: We investigated the expression patterns of MMP-2 and MMP-9 in acquired and congenital melanocytic nevi, and malignant melanoma by immunohistochemical technique. METHOD: Formalin-fixed and paraffin-embedded tissues from 4 junctional nevi, 4 compound nevi, 5 intradermal nevi, 6 congenital melanocytic nevi, and 6 malignant melanomas were immunolabelled with monoclonal antibodies directed against MMP-2 and MMP-9. RESULT: The benign melanocytic nevi showed negative or low expression for MMP-2 and MMP-9 with the exception of positive staining in involuting neuroid intradermal nevus, and the expression of MMP-9 was detected in 3 cases of congenital melanocytic nevi. The malignant melanoma exhibited high expression of MMP-2 with variable intensity of reactivity in different areas of the tumors and MMP-9 was found to be focally expressed by the tumor cells in intraepidermal and dermoepidermal junction. These findings suggest that the expression of MMP-2 and MMP-9 may be related to tumorigenesis of melanocytic tumors and MMP-9 may be involved in the early stage of tumor progression.
Antibodies, Monoclonal ; Basement Membrane ; Carcinogenesis ; Melanoma* ; Metalloproteases* ; Nevus ; Nevus, Intradermal ; Nevus, Pigmented*

Genipin, an aglycone derived from geniposide found in Gardenia jasminoides, is known to be an excellent natural cross-linker, strong apoptosis inducer, and antiviral agent. Although evidence suggests antiviral activity of genipin in several in vitro viral infection systems, there have been few literatures which review antitumor effects of genipin in a variety of in vitro/in vivo models of cancers yet. In this review, we present some of the latest findings in the studies of genipin focusing on antitumor effects and its mechanisms. In brief, genipin inhibits mitochondrial uncoupling protein 2 to increase accumulation of reactive oxygen species, leading to ROS/c-Jun N-terminal kinase-dependent apoptosis of cancer cells. Genipin also increase tissue inhibitors of metalloproteases (MMP), resulting to decrease activities of MMP-2 which plays a key role in metastasis of cancers. Genipin has shown a biphasic effects on cell death and survival in cancer cells as many other plant-derived phytochemicals do. Finally we discuss the potential of genipin as a promosing novel antitumor agent which could be applicable to chemotherapy and/or chemoprevention for cancers.
Apoptosis ; Cell Death ; Chemoprevention ; Drug Therapy ; Gardenia ; In Vitro Techniques ; Metalloproteases ; Neoplasm Metastasis ; Phytochemicals ; Reactive Oxygen Species

Proteomics is a fast-growing discipline that aims at systematic identification, quantification of proteins and their post-translational modifications in cells. Mass spectrometry-based shotgun proteomics technology is currently one of the mainstream methods for proteomics research. With this method, proteins need to be digested to peptides by site-specific proteases before they can be detected with mass spectrometry. Therefore, site-specific proteases played key roles in this process and so far, a variety of specific proteases have been developed and used in proteomics study. Particularly, the identification, characterization and development of proteases that cleave at the N-termini of corresponding amino acid residues, which are just mirrors to those of typical C-termini proteases, provide novel tools for proteomics analysis. In this review, we summarized the proprieties of LysargiNase, a most recently identified mirror trypsin, and its applications in proteomics research to promote its more widespread usage.
Mass Spectrometry ; Metalloproteases ; chemistry ; metabolism ; Protein Processing, Post-Translational ; Proteomics ; Trypsin ; chemistry

OBJECTIVE: Oxytocin antagonists maybe useful in inhibiting the uterine contractions of preterm labor. One such compound is TT-235. The purpose of this study was to compare the resistance of TT-235 and oxytocin to enzymatic degradation by oxytocinase in pregnant human. METHODS: Blood samples from pregnant women not in labor were incubated in vitro with known amounts of oxytocin and TT-235. Samples were collected at 0, 15, 30, 45 and 60 minute intervals for oxytocin analysis and at 0, 10, 60 and 360 minutes for TT-235 analysis. Oxytocin was analyzed by radioimmunoassay after extraction while TT-235 was analyzed by radioreceptor assay. RESULTS: In human blood, oxytocin was readily metabolized with greater than 83% disappearance over the 60 minute incubation period. In contrast, TT-235 was stable up to 360 minutes of incubation. CONCLUSION: This study suggests that: (1) blood from pregnant human does contain oxytocinase at least in vitro; and (2) TT-235 was resistant to enzymatic degradation by human blood, implying that this oxytocin antagonist may have prolonged activity in vivo in humans.
Cystinyl Aminopeptidase ; Female ; Humans ; Metabolism* ; Obstetric Labor, Premature ; Oxytocin* ; Plasma* ; Pregnancy ; Pregnant Women* ; Radioimmunoassay ; Radioligand Assay ; Uterine Contraction ; Uterus

BACKGROUND AND OBJECTIVES: Medial vestibular nucleus (MVN) neurons are second-order afferent neurons that are involved in the reflex control of the head and eyes. Results from several studies utilizing the intracellular microelectrode recording techniques suggest the presence of several ionic conductances contributes to the regulation of the MVN neuron excitability in rats. In this study, the types and characteristics of voltage-dependent potassium currents were investigated in acutely isolated MVN neurons of postnatal rats. Material and Methods: Electrophysiological recordings were performed by means of the whole cell patch clamp techniques. Coronal slice (400 nm) of the vestibular nucleus region was sequentially treated with pronase 0.2 mg/ml and thermolysin 0.2 mg/ml, then single neurons were mechanically dissociated RESULTS: In a Ca2+ -free solution, low-threshold transient (IA) and high-threshold sustained (IK) currents were recorded. IK was activated (gamma=4.0-12.4 ms at 10 mV) and inactivated (gamma=180-720 ms at 10 mV) more slowly than IA. The half-maximum activation and inactivation potential were -3.1+/-3.4 mV and -38.8+/-3.6 mV, respectively. IA was activated rapidly (gamma=1.0-2.3 ms at 10 mV) and inactivated in 10-60 ms. The half-maximum activation and inactivation potentials were -22.3+/-4.5 mV and -58.4+/-3.8 mV, respectively. When a 4-aminopyridine of 10 mM was applied, IA was almost totally blocked. In a solution with 2 mM Ca2+, calcium dependent potassium currents were identified by application of a Ca2+ free solution and consisted of a transient and a sustained components. Exposure to 0.3 nM apamin induced a reversible reduction of a sustained components. CONCLUSION: These results suggest that MVN neurons express a variety of voltage-dependent potassium currents which are responsible for proper membrane excitability and firing of MVN neurons.
4-Aminopyridine ; Animals ; Apamin ; Calcium ; Fires ; Head ; Membranes ; Microelectrodes ; Neurons* ; Neurons, Afferent ; Patch-Clamp Techniques ; Potassium* ; Pronase ; Rats* ; Reflex ; Thermolysin ; Vestibular Nuclei*

This study was designed to investigate the effects an 8-Br-cGMP on the neuronal activity of rat vestibular nuclear cells. Sprague-Dawley rats aged 14 to 16 days were decapitated under ether anesthesia. After treatment with pronase and thermolysin, the dissociated vestibular nuclear cells were transferred into a chamber on an inverted microscope. Spontaneous action potentials and potassium currents were recorded by standard patch-clamp techniques under current and voltage-clamp modes. Twelve vestibular nuclear cells revealed excitatory responses to 1-5 microM of 8-Br-cGMP, and 3 neurons did not respond to 8-Br-cGMP. Whole potassium currents of vestibular nuclear cells were decreased by 8-Br-cGMP (n=12). After calcium-dependent potassium currents were blocked by tetraethylammonium, the potassium currents were not decreased by 8-Br-cGMP. These experimental results suggest that 8-Br-cGMP changes the neuronal activity of vestibular nuclear cells by blocking the calcium-dependent potassium currents that underlie the afterhyperpolarization.
Action Potentials ; Aged ; Anesthesia ; Animals ; Ether, Ethyl ; Humans ; Neurons ; Nucleotides, Cyclic ; Patch-Clamp Techniques ; Potassium ; Pronase ; Rats ; Rats, Sprague-Dawley ; Tetraethylammonium ; Thermolysin