The relationship of VEGF and PGE2 expression to extracellular matrix remodelling of the tenosynovium in the carpal tunnel syndrome

Tenosynovial thickening within the confined space of the carpal tunnel is thought to be the cause of the carpal tunnel syndrome (CTS). However, little is known about the pathological mechanism of tenosynovial thickening. In this study, the role of prostaglandin E(2) (PGE(2)) and vascular endothelial growth factor (VEGF) (two representative molecules that can induce oedema by increasing vascular permeability) was analysed in CTS by using immunohistochemistry and enzyme-linked immunosorptive assay (ELISA). Expression of these molecules was compared with the patients' clinical histories and a temporary increase in production of these molecules was found in cells within the vessels and synovial lining during the intermediate phase of the syndrome when the histology of the tenosynovium changes from oedematous to fibrotic. Statistical analysis clearly demonstrated that there is a close correlation between the expression of PGE(2) and VEGF. Furthermore, immunohistochemical analysis with anti-proliferating cell nuclear antigen (PCNA) revealed that the area with distinct VEGF expression closely matched the area where endothelial cells, vascular smooth muscle cells, and synovial lining cells proliferate. In contrast, despite marked alteration in the extracellular matrix (ECM) component of the tenosynovium, the fibroblasts responsible for most ECM framework production do not proliferate during any phase of CTS. Histological analysis demonstrated that angiogenesis takes place only during the intermediate phase. Since clusters of capillaries and arterioles are often surrounded by type III collagen-rich, disorganized, degenerate connective tissue, which contains fewer fibroblasts than normal, angiogenesis appears to take place as a part of a regenerative reaction that results in fibrosis. These findings strongly indicate that both PGE(2) and VEGF are expressed in the tenosynovium in CTS during the intermediate phase and induce the histological changes seen in the tenosynovium.     

Forced expression of terminal deoxynucleotidyl transferase in fetal thymus resulted in a decrease in gammadelta T cells and random dissemination of Vgamma3Vdelta1 T cells in skin of newborn but not adult mice

The repertoire of lymphocyte receptor genes encoded in a germline is further diversified by a number of processes, including the template-independent addition of nucleotides (N regions) by means of terminal deoxynucleotidyl transferase (TdT). Normally, mouse gammadelta T cells in the early fetal thymus, whose T-cell receptor (TCR) genes lack N regions and are encoded by Vgamma3-Jgamma1 and Vdelta1-Ddelta2-Jdelta2 with canonical junctions (invariant Vgamma3Vdelta1), are thought to be the precursors of dendritic epidermal T cells (DETC). We generated mutant mice whose endogenous TdT promoter was replaced with the lck promoter through homologous recombination. These mutant mice expressed TdT in fetal thymus, had abundant N regions and infrequent canonical junctions in gamma and delta rearrangements, and showed a decreased number of gammadelta T cells. Various Vgamma3Vdelta1 T cells, most of which had N regions in their TCR genes, were found to disseminate in the skin of newborn mutant mice, whereas normal numbers of DETCs with the invariant Vgamma3Vdelta1 rearrangement were observed in adult mutants. These data demonstrate that the regulation of TdT expression during fetal development is important for the generation of gammadelta T cells, and that Vgamma3Vdelta1 T cells, which have various junctional sequences in their TCR genes, randomly disseminate in skin, but invariant Vgamma3Vdelta1 T cells have a great advantage for proliferation in skin.     

Inhibition of abnormal T cell development and autoimmunity in gld mice by transgenic T cell receptor beta chain.

Mice homozygous for the gld (generalized lymphoproliferative disease) mutation developed systemic autoimmune disease and severe lymphadenopathy due to an age-related accumulation in the peripheral lymphoid organs of polyclonal T cells bearing a unique phenotype (CD4-CD8-TCR alpha beta+B220+). These T cells overexpress T cell receptor (TcR) alpha beta chain RNA, proto-oncogenes c-myb and fyn, and proliferate poorly in response to TcR-mediated stimulation. The origin of these T cells is poorly understood. To study the influence of a functionally rearranged TcR beta chain on the T cell developmental abnormality of the gld mutation and autoimmunity, we have backcrossed TcR V beta 8.1-transgenic mice to C3H-gld/gld to homozygosity (transgenic gld mice). In transgenic gld mice, lymphadenopathy was markedly inhibited and the accumulation of CD4-CD8- T cells did not occur, although the remaining T cells overexpressed c-myb and proliferated poorly in response to TcR occupancy. These features indicate that the pattern of proto-oncogene expression and abnormal function persist in phenotypically normal T cells in transgenic gld mice, and that these characteristics can be dissociated from the accumulation of CD4-CD8- T cells. The hypergammaglobulinemia and anti-double-stranded DNA (anti-dsDNA) antibody production was partially improved in transgenic gld mice, supporting the critical role of T cells in abnormal B cell activation described in autoimmunity-prone mice. To investigate further the mechanisms underlying the inhibition of CD4-CD8- T cell accumulation in transgenic gld mice, the fetal ontogeny of T cells in transgenic mice was compared with that of non-transgenic mice. In transgenic thymus, development of TcR alpha beta+ cells was accelerated as detected by earlier expression of CD4, CD8 and TcR in fetal thymus. In contrast, the number of TcR gamma delta+ cells was reduced. We suggest that altered T cell development in transgenic mice directly or indirectly inhibits the accumulation of abnormal T cells in gld mice.     

Characterization of action potential-triggered [Ca2+]i transients in single smooth muscle cells of guinea-pig ileum

1. To characterize increases in cytosolic free Ca²⁺ concentration ([Ca²⁺]_i) associated with discharge of action potentials, membrane potential and [Ca²⁺]_i were simultaneously recorded from single smooth muscle cells of guinea-pig ileum by use of a combination of nystatin-perforated patch clamp and fura-2 fluorimetry techniques.
2. A single action potential in response to a depolarizing current pulse elicited a transient rise in [Ca²⁺]_i. When the duration of the current pulse was prolonged, action potentials were repeatedly discharged during the early period of the pulse duration with a progressive decrease in overshoot potential, upstroke rate and repolarization rate. However, such action potentials could each trigger [Ca²⁺]_i transients with an almost constant amplitude.
3. Nicardipine (1 μM) and La³⁺ (10 μM), blockers of voltage-dependent Ca²⁺ channels (VDCCs), abolished both the action potential discharge and the [Ca²⁺]_i transient.
4. Charybdotoxin (ChTX, 300 nM) and tetraethylammonium (TEA, 2 mM), blockers of large conductance Ca²⁺-activated K⁺ channels, decreased the rate of repolarization of action potentials but increased the amplitude of [Ca²⁺]_i transients.
5. Thapsigargin (1 μM), an inhibitor of SR Ca²⁺-ATPase, slowed the falling phase and somewhat increased the amplitude, of action potential-triggered [Ca²⁺]_i transients without affecting action potentials. In addition, in voltage-clamped cells, the drug had little effect on the voltage step-evoked Ca²⁺ current but exerted a similar effect on its concomitant rise in [Ca²⁺]_i to that on the action potential-triggered [Ca²⁺]_i transient.
6. Similar action potential-triggered [Ca²⁺]_i transients were induced by brief exposures to high-K⁺ solution. They were not decreased, but rather increased, after depletion of intracellular Ca²⁺ stores by a combination of ryanodine (30 μM) and caffeine (10 mM) through an open-lock of Ca²⁺-induced Ca²⁺ release (CICR)-related channels.
7. The results show that action potentials, discharged repeatedly during the early period of a long membrane depolarization, undergo a progressive change in configuration but can each trigger a constant rise in [Ca²⁺]_i. Intracellular Ca²⁺ stores have a role, especially in accelerating the falling phase of the action potential-triggered [Ca²⁺]_i transients by replenishing cytosolic Ca²⁺. No evidence was provided for the involvement of CICR in the action potential-triggered [Ca²⁺]_i transient.

     

Keyhole method for high-speed human cardiac cine MR imaging.

Although electrocardiographic (ECG)-gated magnetic resonance (MR) imaging is widely used for cardiac imaging, it has several disadvantages, such as long imaging time, respiratory artifacts, and motion artifacts induced by arrhythmia. An MR image can be acquired within about 0.3 seconds by using a fast gradient-echo imaging method. When this method is continuously applied, only two to three images can be obtained during a single cardiac cycle. The goal of this study is to obtain cine MR images in a single cardiac cycle using fast gradient-echo imaging combined with the "keyhole" method. The optimal conditions for the keyhole method for cardiac cine imaging were obtained by computer simulation based on a simplified cardiac model. When the read-out direction was set parallel to the cardiac short axis, left ventricular motion was almost correctly reproduced by the keyhole method with acquisition time reduced to one-fourth. J. Magn. Reson. Imaging 1999;10:778-783.     

The validity of the MMSE and SMQ as screening tests for dementia in the elderly general population-- a study of one rural community in Japan

OBJECTIVE: To compare the validity of the Mini Mental State Examination (MMSE) and the Short-Memory Questionnaire (SMQ) as screening tests to detect dementia in the elderly general population. SUBJECTS: Six hundred and sixty-two subjects and their informants from the elderly general population sample who had completed these tests. SETTING: One rural community survey in Japan. METHOD: We used receiver-operating characteristic analysis to compare the performance of the MMSE and the SMQ with the clinical diagnosis of dementia according to DSM-III-R. RESULTS: The areas under the receiver-operating characteristic curve of the MMSE and the SMQ were 0.980 (SE = 0.006) and 0.982 (SE = 0.008), respectively. This differed from chance to a highly significant degree for both the MMSE and the SMQ, but the difference between the two scales was not statistically significant. CONCLUSION: As screening tests to detect dementia in the elderly general population, the SMQ which is assessed by informants demonstrates a statistically significant discriminating ability as well as the MMSE.     

Modulation of platelet aggregation after percutaneous transluminal angioplasty of the iliac artery for atherosclerosis obliterans

BACKGROUND: Platelet aggregation is modulated by blood flow. We investigated whether platelet function is altered during percutaneous transluminal balloon angioplasty in patients with atherosclerosis obliterans. METHODS: Blood samples were obtained from the iliac artery in 9 lower limbs of 7 patients undergoing percutaneous balloon angioplasty of the iliac artery. An agonists-induced platelet aggregation test was performed with an aggregometer. Femoral blood flow was measured with a Doppler velocimeter before and after the procedure. RESULTS: Before dilatation, the maximum platelet aggregation rates (+/- SEM) induced by adenosine phosphate, epinephrine, and arachidonic acid were 54.7% +/- 5.8%, 64.8% +/- 4.3%, and 60.5% +/- 6.1%, respectively. After angioplasty, these values reduced to 36.7% +/- 4.1%, 36.1% +/- 8.6%, and 40.1% +/- 5.0%, respectively (P < .05). The pre-procedural ankle-brachial pressure index, mean flow rate, mean velocity, and shear stress variation were 0.63 +/- 0.1, 218.1 +/- 32.1 mL/min, 9.4 +/- 1.1 cm/sec, and 60.6 +/- 17.7 dyne/cm2, respectively. The mean velocity at the stenotic lesion was 215.1 +/- 83.9 cm/sec, which was significantly greater than those of the distal artery or after angioplasty (P < .01). Both ankle-brachial pressure index and shear stress variation increased after angioplasty to 0.99 +/- 0.07 (P < .05) and 139.8 +/- 17.0 (P < .05) dyne/cm2, but the mean flow rate and the mean velocity (198.3 +/- 24.5 mL/min and 8.8 +/- 1.2 cm/sec after angioplasty) did not change significantly. CONCLUSIONS: These results indicate that activated platelet function at a stenosed artery was decreased after angioplasty, possibly because of normalized blood flow with reduction of stenotic lesion.     

Characteristics of ropivacaine block of Na+ channels in rat dorsal root ganglion neurons

When used for epidural anesthesia, ropivacaine can produce a satisfactory sensory block with a minor motor block. We investigated its effect on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na(+) currents in rat dorsal root ganglion (DRG) neurons to elucidate the mechanisms underlying the above effects. Whole-cell patch-clamp recordings were made from enzymatically dissociated neurons from rat DRG. A TTX-S Na(+) current was recorded preferentially from large DRG neurons and a TTX-R Na(+) current preferentially from small ones. Ropivacaine shifted the activation curve for the TTX-R Na(+) channel in the depolarizing direction and the inactivation curve for both types of Na(+) channel in the hyperpolarizing direction. Ropivacaine blocked TTX-S and TTX-R Na(+) currents, but its half-maximum inhibitory concentration (IC(50)) was significantly lower for the latter current (116 +/- 35 vs 54 +/- 14 microM; P: < 0.01); similar IC(50) values were obtained with the (R)-isomer of ropivacaine. Ropivacaine produced a use-dependent block of both types of Na(+) channels. Ropivacaine preferentially blocks TTX-R Na(+) channels over TTX-S Na(+) channels. We conclude that because TTX-R Na(+) channels exist mainly in small DRG neurons (which are responsible for nociceptive sensation), such selective action of ropivacaine could underlie the differential block observed during epidural anesthesia with this drug. Implications: Whole-cell patch-clamp recordings of tetrodotoxin-sensitive and tetrodotoxin-resistant Na(+) currents in rat dorsal root ganglion neurons showed ropivacaine preferentially blocked tetrodotoxin-resistant Na(+) channels over tetrodotoxin-sensitive Na(+) channels. This could provide a desirable differential sensory blockade during epidural anesthesia using ropivacaine.