[A Case of Refractory Intermittent Hematuria that Occurred during Paclitaxel/Ramucirumab Combination Therapy for Metastatic Gastric Cancer].

A 76-year-old male patient developed right hydronephrosis due to peritoneal and retroperitoneal dissemination after surgery for gastric cancer. A ureteral stent was inserted, and systemic chemotherapy was introduced for metastatic gastric cancer. Disease progression was observed, and paclitaxel/ramucirumab combination therapy was started as the second-line treatment. After seven courses, severe gross hematuria appeared intermittently, and refractory epistaxis was observed concurrently. No hemorrhagic lesion was found in the imaging test and urethrocystoscopy. The patient received conservative treatment, such as blood transfusion, and further examination was planned. However, hematuria and epistaxis resolved spontaneously during the course of treatment. From the clinical course, it was thought to be a hemorrhagic adverse event due to ramucirumab, and the patient's treatment was therefore changed to another drug. The patient recovered without recurrence of gross hematuria.

Suppressive effects of diltiazem and verapamil on delayed rectifier K(+)-channel currents in murine thymocytes.

BACKGROUND: Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and these channels play crucial roles in the lymphocyte activation and proliferation. Since diltiazem and verapamil, which are highly lipophilic Ca(2+) channel blockers (CCBs), exert relatively stronger immunomodulatory effects than the other types of CCBs, they would affect the Kv1.3-channel currents in lymphocytes. METHODS: Employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of these drugs on the channel currents and the membrane capacitance. RESULTS: Both diltiazem and verapamil significantly suppressed the peak and the pulse-end currents of the channels, although the effects of verapamil were more marked than those of diltiazem. Both drugs significantly lowered the membrane capacitance, indicating the interactions between the drugs and the plasma membranes. CONCLUSIONS: This study demonstrated for the first time that CCBs, such as diltiazem and verapamil, exert inhibitory effects on Kv1.3-channels expressed in lymphocytes. The effects of these drugs may be associated with the mechanisms of immunomodulation by which they decrease the production of inflammatory cytokines.

Olopatadine inhibits exocytosis in rat peritoneal mast cells by counteracting membrane surface deformation.

BACKGROUND/AIMS: Besides its anti-allergic properties as a histamine receptor antagonist, olopatadine stabilizes mast cells by inhibiting the release of chemokines. Since olopatadine bears amphiphilic features and is preferentially partitioned into the lipid bilayers of the plasma membrane, it would induce some morphological changes in mast cells and thus affect the process of exocytosis. METHODS: Employing the standard patch-clamp whole-cell recording technique, we examined the effects of olopatadine and other anti-allergic drugs on the membrane capacitance (Cm) in rat peritoneal mast cells during exocytosis. Using confocal imaging of a water-soluble fluorescent dye, lucifer yellow, we also examined their effects on the deformation of the plasma membrane. RESULTS: Low concentrations of olopatadine (1 or 10 µM) did not significantly affect the GTP-γ-S-induced increase in the Cm. However, 100 µM and 1 mM olopatadine almost totally suppressed the increase in the Cm. Additionally, these doses completely washed out the trapping of the dye on the cell surface, indicating that olopatadine counteracted the membrane surface deformation induced by exocytosis. As shown by electron microscopy, olopatadine generated inward membrane bending in mast cells. CONCLUSION: This study provides electrophysiological evidence for the first time that olopatadine dose-dependently inhibits the process of exocytosis in rat peritoneal mast cells. Such mast cell stabilizing properties of olopatadine may be attributed to its counteracting effects on the plasma membrane deformation in degranulating mast cells.

[A Case of Muscle Invasive Bladder Cancer in a Patient with Systemic Lupus Erythematosus].

Systemic lupus erythematosus (SLE) is an autoimmune disease with various symptoms. We present a case of muscle invasive bladder cancer with lymph node swelling caused by SLE. A 60-year-old man was referred to our hospital with high fever and pollakisuria, micro hematuria, proteinuria. We detecteda papillary tumor located behind the left ureteral orifice. Magnetic resonance imaging showed invasion of the tumor to the fat around the bladder. Computed tomography (CT) showed the swelling of left common iliac lymph node and bilateral inguinal lymph nodes. According to cystoscopy, imaging examination and transurethral resection of bladder tumor, we diagnosed it as a bladder cancer (cT3aN3M1). In addition, a close inspection of proteinuria was performed, and SLE was diagnosed. We started steroid therapy under the influence of neutropenia and thrombopenia caused by SLE. The swelling of lymph nodes disappeared on the CT three months later. After the therapy with gemcitabine andcisplatin, radical cystectomy and cutaneous ureterostomy were performed. Pathological examination showed invasive urothelial carcinoma and no lymph node metastasis. He now shows no evidence of disease 18 months after the operation.

HMG-CoA reductase inhibitors pravastatin, lovastatin and simvastatin suppress delayed rectifier K(+)-channel currents in murine thymocytes.

BACKGROUND: Since lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) that trigger lymphocyte activation, statins, which exert immunosuppressive effects, would affect the channel currents. METHODS: Employing the patch-clamp technique in murine thymocytes, we examined the effects of statins on Kv1.3-channel currents and the membrane capacitance (Cm). RESULTS: Pravastatin significantly suppressed the pulse-end currents of the channels. Lovastatin and simvastatin also suppressed the peak currents, significantly decreasing the Cm. CONCLUSIONS: This study demonstrated for the first time that statins inhibit thymocyte Kv1.3-channels. The slow inactivation patterns induced by lovastatin and simvastatin may be associated with their accumulation in the plasma membranes.

Aspirin-induced microscopic surface changes stimulate thrombopoiesis in rat megakaryocytes.

During the process of thrombopoiesis, invaginations of the plasma membrane occur in megakaryocytes. Since acetylsalicylic acid (aspirin), the most commonly used anti-inflammatory and antiplatelet drug, interacts with the lipid bilayers of the plasma membranes, this drug would affect the process of thrombopoiesis. In the present study, employing a standard patch-clamp whole-cell recording technique, we examined the effects of aspirin on delayed rectifier K(+)-channel (Kv1.3) currents and the membrane capacitance in megakaryocytes. Using confocal imaging of di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS) staining, we also monitored the membrane invaginations in megakaryocytes. Aspirin suppressed both the peak and the pulse-end currents with a significant increase in the membrane capacitance. Massive di-8-ANEPPS staining after treatment with aspirin demonstrated the impaired membrane micro-architecture of megakaryocytes. This study demonstrated for the first time that aspirin induces microscopic surface changes in megakaryocytes. Such surface changes were thought to stimulate thrombopoiesis in megakaryocytes as detected by the increase in the membrane invaginations.

[Burned-out testicular tumor diagnosed triggered by paraneoplastic neurological syndrome: a case report].

We report a case of burned-out testicular tumor. A 41-year-old man was referred to our department with swelling of iliac lymph nodes detected by computed tomography screening for cerebellar atrophy. Lymph node biopsy revealed metastasis of seminoma. Ultrasound examination showed an irregular hypoechoic area in his left testis. We diagnosed paraneoplastic neurological syndrome secondary to burned-out testicular tumor. So, we underwent left orchiectomy and chemotherapy. He remains free from disease recurrence 15 months after treatment.

Amphipath-induced plasma membrane curvature controls microparticle formation from adipocytes: novel therapeutic implications for metabolic disorders.

Microparticles produced from the membrane surface of adipocytes promote lipid biosynthesis and angiogenesis in adipose tissues. Thus, they are deeply associated with the onset of metabolic disorders. Despite our understanding of their roles in physiological or pathological responses, we know little about the mechanism by which microparticles are produced from adipocytes. Based on our previous studies using rat megakaryocytes or mast cells during exocytosis, we proposed that membrane curvature induced by amphiphilic reagents, such as chlorpromazine or salicylate, facilitate or inhibit the formation of microparticles. Since the plasma membranes in adipocytes share many common biophysiological features with those in megakaryocytes or mast cells during exocytosis, the same stimulatory or inhibitory mechanism of microparticle formation would exist in adipocytes. Therefore, we hypothesize here that amphiphilic reagents would also change the membrane curvature in adipocytes, and that such changes would facilitate or inhibit the microparticle formation from adipocytes. Our hypothesis is unique because it sheds light for the first time on the physiological mechanism by which microparticles are produced in adipocytes. It is also important because the idea could have novel therapeutic implications for metabolic disorders that are triggered by increases in the microparticle formation.

[Case of primary malignant lymphoma of the bladder].

We report a case of primary malignant lymphoma of the bladder. An 87-year-old female visited our hospital for incidental bladder tumor. Cystoscopic examination demonstrated a non-papillary tumor over 10 mm in diameter. We performed transurethral resection of the bladder tumor. Histological examination showed malignant lymphoma, diffuse large B cell type. After further examination, it was diagnosed as primary malignant lymphoma of the bladder, stage IA E(Ann Arbor classification). We performed six courses of R-CHOP regimen (rituximab, cyclophosphamide, vincristine, doxorubicin, predonisolone). We did not find any local or distant recurrences after eight months' follow up.

Flagellin/TLR5 signaling potentiates airway serous secretion from swine tracheal submucosal glands.

Airway serous secretion is essential for the maintenance of mucociliary transport in airway mucosa, which is responsible for the upregulation of mucosal immunity. Although there are many articles concerning the importance of Toll-like receptors (TLRs) in airway immune systems, the direct relationship between TLRs and airway serous secretion has not been well investigated. Here, we focused on whether TLR5 ligand flagellin, which is one of the components of Pseudomonas aeruginosa, is involved in the upregulation of airway serous secretion. Freshly isolated swine tracheal submucosal gland cells were prepared, and the standard patch-clamp technique was applied for measurements of the whole cell ionic responses of these cells. Flagellin showed potentiating effects on these oscillatory currents induced by physiologically relevant low doses of acetylcholine (ACh) in a dose-dependent manner. These potentiating effects were TLR5 dependent but TLR4 independent. Both nitric oxide (NO) synthase inhibitors and cGMP-dependent protein kinase (cGK) inhibitors abolished these flagellin-induced potentiating effects. Furthermore, TLR5 was abundantly expressed on tracheal submucosal glands. Flagellin/TLR5 signaling further accelerated the intracellular NO synthesis induced by ACh. These findings suggest that TLR5 takes part in the airway mucosal defense systems as a unique endogenous potentiator of airway serous secretions and that NO/cGMP/cGK signaling is involved in this rapid potentiation by TLR5 signaling.

Decreased expression of a novel prostaglandin transporter, OAT-PG, facilitates renocortical PGE2 accumulation during rat pregnancy.

BACKGROUND: Prostaglandin (PG)-specific organic anion transporter (OAT-PG) is a recently identified renal transporter involved in the local clearance of prostaglandin E2 (PGE2). Since the renal biosynthesis of PGE2 is not increased during pregnancy, this transporter expression would affect the gestational changes in the renal PGE2 content. METHODS: Kidneys from rats at different gestational stages were used to examine gestational changes in the renocortical PGE2 concentration. The renal expression of OAT-PG and the enzymes for PGE2 synthesis was also examined sequentially, together with the gestational changes in renal renin production. RESULTS: The renocortical PGE2 concentration was significantly increased during midterm to late pregnancy, with a maximum increase of 47.6 ± 11.5% from the virgin value. Although the expression of the enzymes, such as cyclooxygenases and PG synthases, was not increased, that of OAT-PG was significantly decreased throughout pregnancy, inversely correlating with changes in the renocortical PGE2 concentration. Renal renin production was significantly increased during pregnancy. CONCLUSION: This study demonstrated for the first time that the tissue PGE2 concentration was increased in pregnant rat kidneys, which may be associated with the gestational rise in glomerular filtration rate. The decreased expression of OAT-PG was thought to be responsible for the increased tissue PGE2 content.

Amphipaths differentially modulate membrane surface deformation in rat peritoneal mast cells during exocytosis.

BACKGROUND/AIMS: Salicylate and chlorpromazine exert differential effects on the chemokine release from mast cells. Since these drugs are amphiphilic and preferentially partitioned into the lipid bilayers of the plasma membranes, they would induce some morphological changes in mast cells and thus affect the process of exocytosis. METHODS: Employing the standard patch-clamp whole-cell recording technique, we examined the effects of salicylate and chlorpromazine on the membrane capacitance (Cm) during exocytosis in rat peritoneal mast cells. Using confocal imaging of a water-soluble fluorescent dye, lucifer yellow, we also examined their effects on plasma membrane deformation of the cells. RESULTS: Salicylate dramatically accelerated the GTP-γ-S-induced increase in the Cm immediately after its application, whereas chlorpromazine significantly suppressed the increase. Treatment with salicylate increased the trapping of the dye on the cell surface, while treatment with chlorpromazine completely washed it out, indicating that both drugs induced membrane surface deformation in mast cells. CONCLUSION: This study demonstrated for the first time that membrane amphipaths, such as salicylate and chlorpromazine, may oppositely modulate the process of exocytosis in mast cells, as detected by the changes in the Cm. The plasma membrane deformation induced by the drugs was thought to be responsible for their differential effects.

Differential effects of clarithromycin and azithromycin on delayed rectifier K(+)-channel currents in murine thymocytes.

CONTEXT: Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since macrolide antibiotics, such as clarithromycin and azithromycin, exert immunomodulatory effects, they would affect the Kv1.3-channel currents in lymphocytes. OBJECTIVE: This study determined the physiological involvement in the mechanisms of immunomodulation by these antibiotics. MATERIALS AND METHODS: Employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of 30 and 100 µM clarithromycin and azithromycin on the Kv1.3-channel currents and the membrane capacitance. RESULTS: Clarithromycin significantly suppressed the peak currents (30 µM, 178 ± 5.6 to 111 ± 2.0 pA/pF; 100 µM, 277 ± 4.4 to 89.6 ± 10 pA/pF) and the pulse-end currents (30 µM, 47.5 ± 2.2% to 15.5 ± 3.3%; 100 µM, 48.5 ± 1.4% to 15.8 ± 1.0%) of thymocyte Kv1.3-channels without significant effects on the membrane capacitance. In contrast, azithromycin did not affect the channel currents. However, it significantly decreased the membrane capacitance (30 µM, 4.68 ± 0.14 to 3.74 ± 0.13 pF; 100 µM, 4.47 ± 0.06 to 3.37 ± 0.08 pF), indicating its accumulation in the plasma membrane. DISCUSSION AND CONCLUSION: This study demonstrated for the first time that clarithromycin exerts inhibitory effects on thymocyte Kv1.3-channel currents, while azithromycin decreases the membrane capacitance without affecting the channel currents. These differences in the effects of the macrolide antibiotics may reflect differences in the mechanisms of immunomodulation by which they control the production of cytokines.

Benidipine persistently inhibits delayed rectifier K(+)-channel currents in murine thymocytes.

Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since 1,4-dihydropyridine (DHP) Ca(2+) channel blockers (CCBs), which are highly lipophilic, exert relatively stronger immunomodulatory effects than the other types of CCBs, they would affect the Kv1.3-channel currents in lymphocytes. In the present study, employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of benidipine, one of the most lipophilic DHPs, on the channel currents and the membrane capacitance and compared them with those of nifedipine. Both drugs significantly suppressed the peak and the pulse-end currents of the channels with significant decreases in the membrane capacitance. However, the effects of benidipine were more marked than those of nifedipine and were irreversible after the drug withdrawal. This study demonstrated for the first time that DHP CCBs, such as nifedipine and benidipine, exert inhibitory effects on thymocyte Kv1.3-channel currents. The persistent effect of benidipine was thought to be associated with its sustained accumulation in the plasma membranes as detected by the long-lasting decrease in the membrane capacitance.

Overexpression of Delayed Rectifier K(+) Channels Promotes In situ Proliferation of Leukocytes in Rat Kidneys with Advanced Chronic Renal Failure.

Leukocytes, such as lymphocytes and macrophages, predominantly express delayed rectifier K(+) channels (Kv1.3), and the channels play crucial roles in the activation and proliferation of the cells. Since lymphocytes are activated in patients with end-stage renal disease (ESRD), the channels expressed in those cells would contribute to the progression of renal fibrosis in advanced-stage chronic renal failure (CRF). In the present study, using a rat model with advanced CRF that underwent 5/6 nephrectomy followed by a 14-week recovery period, we examined the histopathological features of the kidneys and the leukocyte expression of Kv1.3-channels and cell cycle markers. Age-matched sham-operated rats were used as controls. In the cortical interstitium of advanced CRF rat kidneys, leukocytes proliferated in situ and overexpressed Kv1.3 channel protein in their cytoplasm. Treatment with margatoxin, a selective Kv1.3-channel inhibitor, significantly suppressed the number of leukocytes and the progression of renal fibrosis with a significant decrease in the cortical cell cycle marker expression. This study demonstrated for the first time that the number of leukocytes was dramatically increased in rat kidneys with advanced CRF. The overexpression of Kv1.3 channels in the leukocytes was thought to contribute to the progression of renal fibrosis by stimulating cell cycling and promoting cellular proliferation.

Inner mitochondrial maxi-K⁺ channels in neonatal renal tubular cells: novel therapeutic targets to control apoptosis.

In developing kidneys, the total cell population is partly regulated by apoptosis. Despite our understanding of the molecular involvement in the regulatory pathway of apoptosis, we know little about the physiological involvement. Cardiomyocytes express large conductance voltage- and Ca(2+)-activated K(+) (maxi-K(+)) channels in their inner mitochondrial membranes. Triggering the mitochondrial K(+) influx necessary to inhibit apoptosis, the channels play cytoprotective roles during ischemic injury. Since proximal tubular cells in neonatal kidneys are physiologically under hypoxic stress, and since the channel activity is stimulated by hypoxia, those cells would share the same regulatory mechanism of apoptosis with ischemic cardiomyocytes. Therefore, we hypothesize here that the proximal tubular cells in neonatal kidneys would also express the maxi-K(+) channels in their inner mitochondrial membranes, and that the channels would play regulatory roles in apoptosis. Our hypothesis is unique because it sheds light for the first time on a physiological mechanism that involves the mitochondrial membranes in developing kidneys. It is also important because the idea could have novel therapeutic implications for kidney diseases that are associated with apoptosis.

Suppressive effects of nonsteroidal anti-inflammatory drugs diclofenac sodium, salicylate and indomethacin on delayed rectifier K+-channel currents in murine thymocytes.

Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and the channels play crucial roles in the lymphocyte activation and proliferation. Since nonsteroidal anti-inflammatory drugs (NSAIDs), the most commonly used analgesic and antipyretic drugs, exert immunomodulatory effects, they would affect the channel currents in lymphocytes. In the present study, employing the standard patch-clamp whole-cell recording technique, we examined the effects of diclofenac sodium, salicylate and indomethacin on the channel currents in murine thymocytes and the membrane capacitance. Diclofenac sodium and salicylate significantly suppressed the pulse-end currents of the channel. However, indomethacin suppressed both the peak and the pulse-end currents with a significant increase in the membrane capacitance. This study demonstrated for the first time that NSAIDs, such as diclofenac sodium, salicylate and indomethacin, exert inhibitory effects on thymocyte Kv1.3-channel currents. The slow inactivation pattern induced by indomethacin was thought to be associated with microscopic changes in the plasma membrane surface detected by the increase in the membrane capacitance.

Toll-like receptor 4 potentiates Ca2+-dependent secretion of electrolytes from swine tracheal glands.

Airway surface fluids are mainly secreted from submucosal glands, and play important roles in the defense of airways via the up-regulation of mucociliary transport, resulting in an exclusion of many microbes or foreign substances. Although there are many articles concerning the importance of Toll-like receptors (TLRs) in airway immune systems, whether TLRs directly cooperate with tracheal submucosal glands to increase secretion remains unknown. We investigated the effects of ligands of the three TLR subtypes (TLR2, TLR3, and TLR4) on the physiologic secretion of electrolytes by using a patch-clamp technique. Among these TLRs, only the TLR4 ligand, LPS, showed potentiating effects on acetylcholine (ACh)-induced ionic currents in a dose-dependent manner. These potentiating effects were completely abolished by pretreatment with a specific TLR4 antagonist or the anti-TLR4 antibody. LPS per se exerted no appreciable effect on baseline currents. Next, we demonstrated the abundant expression of TLR4 in submucosal gland acinar cells by using immunofluorescent staining and RT-PCR. Furthermore, we revealed that both nitric oxide synthase inhibitors and cyclic guanosine monophosphate (cGMP)-dependent protein kinase (cGK) inhibitors abolished the LPS-induced potentiating effects completely. Analyses of fluorescence intensities, using an intracellular nitric oxide (NO) indicator, demonstrated that LPS could further increase the ACh-induced synthesis of NO. These findings suggest that TLR4 takes part in airway mucosal defense systems as a unique exogenous potentiator of electrolyte-water secretion from submucosal gland acinar cells, and that NO/cGMP/cGK signaling is involved in this rapid TLR4 signaling pathway.

Compensatory thrombopoietin production from the liver and bone marrow stimulates thrombopoiesis of living rat megakaryocytes in chronic renal failure.

BACKGROUND/AIMS: Decreased thrombopoiesis has been ascribed a role in the pathogenesis of uremic bleeding in chronic renal failure (CRF). However, serum thrombopoietin (TPO) levels are usually elevated in CRF patients, suggesting increased thrombopoiesis. The aim of this study was to determine the thrombopoietic activity in CRF. METHODS: Male Sprague-Dawley rats that underwent 5/6 nephrectomy were used as the model of CRF. Age-matched sham-operated rats were used as controls. Single megakaryocytes were isolated from the rat bone marrow, and their size distribution was examined. Megakaryocyte membrane invaginations were monitored by confocal imaging of di-8-ANEPPS staining, and patch clamp whole-cell recordings of membrane capacitance. TPO gene expression was assessed in various tissues. RESULTS: Circulating platelet counts and the number of large megakaryocytes were increased in the bone marrow of CRF rats. Massive di-8-ANEPPS staining and increased membrane capacitance in large megakaryocytes demonstrated increased membrane invaginations. Unaffected Kv1.3-channel currents per cell surface area demonstrated unaltered channel densities. TPO transcription was decreased in the renal cortex but increased in the liver and bone marrow of CRF rats. CONCLUSION: Increased thrombopoiesis in CRF was thought to be a reactive mechanism to platelet dysfunction. Increased TPO production from the liver and bone marrow compensated for decreased production from damaged kidneys.