Kihachiro Abe

Ca2+ channel properties in smooth muscle cells of the urinary bladder from pig and human

Ca(2+) channel properties of pig and human bladder smooth muscle were investigated utilizing standard whole-cell patch clamp techniques. Both the amplitude obtained and the current density of Ca(2+) channel current evoked by step depolarization were larger in human than in pig myocytes. The inward currents were sensitive to an L-type Ca(2+) channel antagonist, nifedipine, the effects of which were not significantly different between species. In both species, prior application of ATP (0.1 mM) had no effect on activation of this voltage-sensitive channel current, while a muscarinic receptor agonist, carbachol (0.1 mM), significantly attenuated the amplitude of this current. Furthermore, inclusion of GDP-beta-S or Heparin in the pipette abolished or had no effect on the suppression of Ca(2+) current by carbachol, respectively. These results forward the pig as a good model for the human in detrusor Ca(2+) channel properties, especially with regard to neural modulation, although voltage-sensitive Ca(2+) channels seem to make greater contribution in human bladder physiology.

The inhibitory effect of alendronate, a nitrogen‐containing bisphosphonate on the PI3K–Akt–NFκB pathway in osteosarcoma cells

Bisphosphonates are inhibitors of tumor cell growth as well as of bone resorption by inducing cell apoptosis. However, little is known regarding the mechanisms by which the drug induces cell apoptosis. The aim of the present study was to determine the effect of alendronate, one of the nitrogen‐containing bisphosphonates on the phoshoinositide 3‐kinase (PI3K)–Akt–NFκB pathway, the major cell survival pathway. The PI3K–Akt–NFκB pathway was activated in the osteosarcoma cell line MG‐63 treated with tumor necrosis factor‐α or insulin. Saos‐2 was also used in some experiments. This was assessed by the production of phosphatidylinositol 3,4,5‐trisphosphate (PtdIns(3,4,5)P3), increased PI3K activity, phosphorylation of Akt at serine 473 and threonine 308, increase in activity of the inhibitor of nuclear factor κB (IκB) kinase (IKK) and finally phosphorylation of IκB and its subsequent degradation. Pretreatment with alendronate at 100 μM for 24 h prior to the stimulation with tumor necrosis factor‐α or insulin partially inhibited the IκB phosphorylation and degradation. These events were more clearly observed in the presence of inhibitors of proteasomes, which are responsible for the degradation of IκB. The drug also partially inhibited the activity of IKK, but almost fully inhibited the phosphorylation of Akt and the production of PtdIns(3,4,5)P3. The inhibitory effect of alendronate on IκB phosphorylation and degradation was not attenuated by the exogenous addition of geranylgeraniol to replenish the cytosolic isoprenyl lipid substrate. The present findings demonstrate that alendronate inhibited the PI3K–Akt–NFκB cell survival pathway at the point of PI3K activation, thus indicating the presence of new targets of alendronate.

Cyclic GMP-dependent but G-kinase-independent inhibition of Ca2+-dependent Cl- currents by NO donors in cat tracheal smooth muscle.

1 The effects of NO donors on Ca2+‐dependent Cl− currents (ICl(Ca)) were investigated in freshly isolated cat tracheal myocytes using the whole‐cell patch clamp technique. 2 With nystatin‐perforated whole‐cell recording, carbachol (CCh, ≥ 1 μm) induced a transient inward current (ICCh) with a reversal potential of about ‐20 mV. Activation of ICCh probably occurred through the M3 muscarinic receptor, since nanomolar concentrations of 4‐diphenylacetoxy‐N‐methylpiperidine methobromide (4‐DAMP) greatly inhibited this current, while 11‐(2‐(diethylamino)methyl)‐1‐piperidinylacetyl)‐5,11‐dihydro‐6H‐pyrido (2,3β) (1,4)benzodiazepine‐6‐one (AF‐DX 116) or pirenzepine at concentrations of up to 1 μm were almost ineffective. 3 Chloride channel/transporter blockers such as DIDS (100 μm), anthracene‐9‐carboxylic acid (9‐AC, 100 μm) and niflumic acid (100 μm) greatly inhibited ICCh, but cation channel blockers, such as nifedipine (10 μm), Zn2+ (500 μm) or Gd3+ (500 μm), were without effect. 4 Activation of ICCh was strongly attenuated by pretreatment with ryanodine (4 μm) plus caffeine (10 mM). Addition of neomycin (1 mM) into the bath or inclusion of heparin (3 mg ml−1) in the pipette abolished a substantial part of ICCh. These results suggest that ICCh is ICl(Ca), which is activated by inositol 1,4,5‐trisphosphate (IP3)‐mediated Ca2+ release. 5 The nitric oxide donor S‐nitroso‐N‐acetyl penicillamine (SNAP) reduced the amplitude of ICCh dose dependently (IC50, ≈10 μm). Similar inhibition was also exerted by other types of NO donor such as glyceryl trinitrate (GTN) and (±)‐E‐methyl‐2‐(E‐hydroxyimitol)‐5‐nitro‐6‐methoxy‐3‐hexeneamide (NO‐R). 6 SNAP‐induced ICCh inhibition was effectively antagonized by Methylene Blue (1‐100 nM), and mimicked by dibutyryl cGMP (db‐cGMP) (0.5‐1 mM), whereas two structurally distinct types of cGMP‐dependent (G)‐kinase inhibitor, N‐(2‐aminoethyl)‐5‐isoquinilinesulphonamide (H‐8, 2.5 μm) and KT5823 (1 μm), failed to counteract the inhibitory effects of SNAP or db‐cGMP. Another G‐kinase‐specific inhibitor Rp‐8‐(para‐chlorophenylthio)guanosine‐3′,5′‐cyclic monophosphorothioate (Rp‐8‐pCPT‐cGMPS; 1 μm) itself caused a marked reduction in ICCh. 7 SNAP (100 μm) or db‐cGMP (100 μm) exhibited no inhibitory actions, when caffeine (10 mM) or photolytically released IP3 were used instead of CCh to activate the inward current. 8 These results suggest that inhibition of ICCh by NO donors involves a cGMP‐dependent but G‐kinase‐independent mechanism, which may operate at a site(s) between the muscarinic (M3) and IP3 receptors.

Accumulation of human T lymphotropic virus type I-infected T cells in the salivary glands of patients with human T lymphotropic virus type I- associated Sjogren's syndrome

OBJECTIVE To clarify the involvement of human T lymphotropic virus type I (HTLV-I) in the pathogenesis of Sjogrens syndrome (SS). METHODS In HTLV-I-seropositive patients with SS, HTLV-I proviral DNA in the labial salivary glands (SG) was detected by polymerase chain reaction (PCR) amplification of the extracted cellular DNA, and the localization in the SG was examined by in situ PCR hybridization. RESULTS The cellular DNA extracted from the SG contained full HTLV-I proviral DNA, which was present in the nucleus of the infiltrating T cells, but not in either the SG epithelial cells or the acinar cells. Furthermore, the viral loads in the SG were approximately 8 times to 9 x 10(3) times higher than those in the peripheral blood mononuclear cells. CONCLUSION Accumulation of HTLV-I-infected T cells in the SG suggests that HTLV-I likely causes the self-reactive T cells to proliferate, which, as a result, induces SS.

Aplasia of the submandibular gland

Summary A 34-year-old Japanese male had pain radiating from his right mandibular body to the temporal region. Computerized tomography was undertaken to examine his cerebral status. It eventually revealed the absence of the right submandibular gland, although the left submandibular gland was present. The corresponding space was occupied by a lymph node. Furthermore, sialography showed the existence of Whartons duct only. The literature on this rare occurrence is reviewed and the significance to the patient discussed.

An iatrogenic foreign body (dental bur) in the maxillary antrum: a report of two cases.

Two cases of foreign bodies of the antrum are reported. One was a turbine bur which presumably entered through an oro-antral fistula after a tooth extraction. The other was also a turbine bur where the mode of entry was not clear (lack of oro-antral fistula), but it presumably entered through the socket of the extracted tooth. The mucosa of the antrum appeared normal in spite of the lengthy presence of the foreign body

Dual Modulation of Airway Smooth Muscle Contraction by Th2 Cytokines via Matrix Metalloproteinase-1 Production

Altered contractility of airway smooth muscle (SM) is one of the main causes of allergic asthma, in which the predominance of Th2 over Th1 cytokines plays a central role. In the present study, we examine the effects of Th2 cytokines on airway SM contraction. Treatment with a low concentration of IL-4 (0.2 ng/ml) for 6 h augmented, whereas higher concentrations (2–20 ng/ml) inhibited, agonist-induced contractions of collagen gels containing bovine tracheal SM cells. Another Th2 cytokine (IL-13) showed an augmentation of gel contraction in the concentration range of 20–200 ng/ml. IL-4 and IL-13 increased mRNA expression and protein secretion of matrix metalloproteinase (MMP)-1, but these cytokines did not affect Ca2+-mobilizing properties and phosphorylation levels of myosin L chain in bovine tracheal SM cells. These changes were sensitive to wortmannin, an inhibitor of PI3K, but not to leflunomide, an inhibitor of STAT6. Scanning electron microscope observation revealed that collagen fibers twining around SM cells were completely dissolved in 20 ng/ml IL-4-treated gels and reorganized into basket-like structure in 20 ng/ml IL-13-treated gels. Exogenous application of high and low concentrations of MMP-1 also induced the inhibition and augmentation of gel contraction, respectively. Furthermore, nonselective MMP inhibitor galardin suppressed the effects of IL-4 and IL-13 on gel contraction, and MMP-1-targeted small-interfering RNA reversed the inhibitory effects of IL-4 on gel contraction to the augmentation. This indicates that Th2 cytokines modulate airway contraction without affecting cellular contractility but by secreting MMP-1 from the SM cells via PI3K activation and changing cell-to-matrix interactions.

Widespread radiopacity of jaw bones in familial adenomatosis coli

Abnormalities of jaw bones and teeth were evaluated in 37 patients with familial adenomatosis coli (FAC) by means of orthopantomography. Osteomatous radiopaque lesions were evident in 75.7 percent of FAC patients (focal type: 62.2% and wide spread type: 13.5%), odontomes in 29.7% peripheral osteomas in 13.5%, unerupted teeth in 16.2% and supernumerary unerupted teeth in 16.2%. Five of the 37 FAC patients had an unusual widespread type of radiopacity with other abnormalities. Combined abnormalities were most frequent in patients with this type in comparison with patients with the focal type. Osteomas and peripheral osteomas were revealed in this type with statistical significance. Biopsy performed in one patient revealed an osteoma. These results suggest that the multiple abnormalities seen in oral X-ray examination may predict the occult existence of familial adenomatosis coli and these widespread radiopaque lesions probably represent the most extensive manifestation of FAC.

Submandibular sialoadenitis due to a foreign body

A case of a painful swelling of a submandibular gland in a 62-year-old woman is reported. This eventually proved to be caused by a foreign body (fish bone) in the main intrasalivary duct of the gland.

Mechanisms of vancomycin-induced histamine release from rat peritoneal mast cells

The mechanisms of vancomycin (VCM)-induced histamine release were studied with rat peritoneal mast cells. VCM (>1×10−3M) released histamine from the isolated mast cells in a dose-dependent and noncytotoxic manner. In the absence of extracellular Ca2+, the histamine release was reduced markedly. When the intracellular Ca2+ was depleted, it was further decreased. The Fura-2-loaded single mast cells showed a biphasic increase in the intracellular Ca2+ concentration ([Ca2+]i) by VCM: the first transient and the second sustained components. In the absence of extracellular Ca2+, the transient component was unchanged, while the sustained component was eliminated completely. The IP3 content in the mast cells increased within 10 s after the application of VCM. These results suggest that VCM releases histamine from rat peritoneal mast cells via an IP3 production and increase in [Ca2+]i.