Subjective perceptions that affect the continued employment of persons with mental disabilities in Japan: A mixed-methods study

BACKGROUND

Among people with mental disabilities in Japan, 50.7% have left employment within a year despite the provision of employment support. Their subjective perceptions are likely relevant, as many causes for leaving employment are personal. However, thus far, employment continuity assessment has been based on objective indicators, while subjective evaluation remains underdeveloped.

OBJECTIVE

We conducted a mixed-methods study to identify the subjective characteristics that impact the ability of persons with mental disabilities to continue working while receiving employment support.

METHODS

In total, 41 participants with mental disabilities in continuous employment were included in the study, and data were collected using a demographic and employment status questionnaire and the Worker's Role Interview. Further, to clarify the constructs related to subjective perceptions of work continuity, the step for coding and theorization (SCAT) method was utilized.

RESULTS

The results revealed five overarching superordinate concepts and 12 subordinate concepts of subjective perceptions regarding maintaining the current work and the future for participants who continue to work. These perceptions may be related to the participants' experience and the time course of work continuity. Subjective perceptions of difficulty levels were found to be the most and the least difficult for a reasonable accommodation without specific rules and awareness of the effects of work concepts, respectively.

CONCLUSION

This research could facilitate the development of an employment support system based on people with mental disabilities' subjective needs, thus contributing to their continued employment.

2-Deoxy-d-glucose induces deglycosylation of proinflammatory cytokine receptors and strongly reduces immunological responses in mouse models of inflammation

Anti‐proinflammatory cytokine therapies against interleukin (IL)‐6, tumor necrosis factor (TNF)‐α, and IL‐1 are major advancements in treating inflammatory diseases, especially rheumatoid arthritis. Such therapies are mainly performed by injection of antibodies against cytokines or cytokine receptors. We initially found that the glycolytic inhibitor 2‐deoxy‐d‐glucose (2‐DG), a simple monosaccharide, attenuated cellular responses to IL‐6 by inhibiting N‐linked glycosylation of the IL‐6 receptor gp130. Aglycoforms of gp130 did not bind to IL‐6 or activate downstream intracellular signals that included Janus kinases. 2‐DG completely inhibited dextran sodium sulfate‐induced colitis, a mouse model for inflammatory bowel disease, and alleviated laminarin‐induced arthritis in the SKG mouse, an experimental model for human rheumatoid arthritis. These diseases have been shown to be partially dependent on IL‐6. We also found that 2‐DG inhibited signals for other proinflammatory cytokines such as TNF‐α, IL‐1β, and interferon ‐γ, and accordingly, prevented death by another inflammatory disease, lipopolysaccharide (LPS) shock. Furthermore, 2‐DG prevented LPS shock, a model for a cytokine storm, and LPS‐induced pulmonary inflammation, a model for acute respiratory distress syndrome of coronavirus disease 2019 (COVID‐19). These results suggest that targeted therapies that inhibit cytokine receptor glycosylation are effective for treatment of various inflammatory diseases.

Virus-infection in cochlear supporting cells induces audiosensory receptor hair cell death by TRAIL-induced necroptosis

Although sensorineural hearing loss (SHL) is relatively common, its cause has not been identified in most cases. Previous studies have suggested that viral infection is a major cause of SHL, especially sudden SHL, but the system that protects against pathogens in the inner ear, which is isolated by the blood-labyrinthine barrier, remains poorly understood. We recently showed that, as audiosensory receptor cells, cochlear hair cells (HCs) are protected by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker's organ) cells (GERCs) against viral infections. Here, we found that virus-infected SCs and GERCs induce HC death via production of the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Notably, the HCs expressed the TRAIL death receptors (DR) DR4 and DR5, and virus-induced HC death was suppressed by TRAIL-neutralizing antibodies. TRAIL-induced HC death was not caused by apoptosis, and was inhibited by necroptosis inhibitors. Moreover, corticosteroids, the only effective drug for SHL, inhibited the virus-induced transformation of SCs and GERCs into macrophage-like cells and HC death, while macrophage depletion also inhibited virus-induced HC death. These results reveal a novel mechanism underlying virus-induced HC death in the cochlear sensory epithelium and suggest a possible target for preventing virus-induced SHL.

Nonpharmacological Treatment for Supporting Social Participation of Adults with Depression

BACKGROUND

Social withdrawal is predominantly seen among adults with depression. However, a dearth of reviews exists that explore nonpharmacological treatments, especially occupational therapy (OT) interventions and their effect in promoting social participation. The aim of this research was to review what intervention programs are conducted to support the social participation of adults with depression and their effectiveness.

METHOD

A systematic review was performed wherein relevant articles were searched in PubMed, CINAHL, Wiley Online Library, PsycINFO, and OTseeker databases and AJOT, BJOT, SJOT, and OTMH journals. Only English articles published from January 2010 to December 2018, which tackled intervention for adults aged 20-60 years with depression, were considered. Ten out of 918 studies met the screening criteria.

RESULT

Among the ten studies, the effective intervention programs were categorized as either occupation-based intervention (OBI) or cognitive behavioral therapy-based intervention (CBT-BI). These programs sought the following outcomes: behavioral change in social participation (n = 4), reduction of depression or depressive symptoms (n = 13), life satisfaction (n = 4), and quality of life (QoL) (n = 1). Studies showed moderate (n = 3) to strong (n = 7) level of certainty, whereas they also revealed high to unclear (n = 3) and low (n = 7) risk of bias.

CONCLUSION

Both OBI such as animal-assisted therapy and CBT-BI such as behavioral change program and health education have a strong level of certainty and low risk of bias in promoting social participation by supporting positive behavioral change and reducing depressive symptoms. Furthermore, the sport and exercise program of OBI was popular in encouraging participation and engagement with other people. Other programs were suggested for combined interventions to support social participation, life satisfaction, and QoL.

Cochlear supporting cells function as macrophage-like cells and protect audiosensory receptor hair cells from pathogens

To protect the audiosensory organ from tissue damage from the immune system, the inner ear is separated from the circulating immune system by the blood-labyrinth barrier, which was previously considered an immune-privileged site. Recent studies have shown that macrophages are distributed in the cochlea, especially in the spiral ligament, spiral ganglion, and stria vascularis; however, the direct pathogen defence mechanism used by audiosensory receptor hair cells (HCs) has remained obscure. Here, we show that HCs are protected from pathogens by surrounding accessory supporting cells (SCs) and greater epithelial ridge (GER or Kölliker’s organ) cells (GERCs). In isolated murine cochlear sensory epithelium, we established Theiler’s murine encephalomyelitis virus, which infected the SCs and GERCs, but very few HCs. The virus-infected SCs produced interferon (IFN)-α/β, and the viruses efficiently infected the HCs in the IFN-α/β receptor-null sensory epithelium. Interestingly, the virus-infected SCs and GERCs expressed macrophage marker proteins and were eliminated from the cell layer by cell detachment. Moreover, lipopolysaccharide induced phagocytosis of the SCs without cell detachment, and the SCs phagocytosed the bacteria. These results reveal that SCs function as macrophage-like cells, protect adjacent HCs from pathogens, and provide a novel anti-infection inner ear immune system.

Isolation and characterization of dental epithelial cells derived from amelogenesis imperfecta rat

OBJECTIVE

Disruption of the third zinc finger domain of specificity protein 6 (SP6) presents an enamel-specific defect in a rat model of amelogenesis imperfecta (AMI rats). To understand the molecular basis of amelogenesis imperfecta caused by the Sp6 mutation, we established and characterized AMI-derived rat dental epithelial (ARE) cells.

MATERIALS AND METHODS

ARE cell clones were isolated from the mandibular incisors of AMI rats, and amelogenesis-related gene expression was analyzed by reverse transcription polymerase chain reaction (RT-PCR). Localization of wild-type SP6 (SP6WT) and mutant-type SP6 (SP6AMI) was analyzed by immunocytochemistry. SP6 transcriptional activity was monitored by rho-associated protein kinase 1 (Rock1) promoter activity with its specific binding to the promoter region in dental (G5 and ARE) and non-dental (COS-7) epithelial cells.

RESULTS

Isolated ARE cells were varied in morphology and gene expression. Both SP6WT and SP6AMI were mainly detected in nuclei. The promoter analysis revealed that SP6WT and SP6AMI enhanced Rock1 promoter activity in G5 cells but that enhancement by SP6AMI was weaker, whereas no enhancement was observed in the ARE and COS-7 cells, even though SP6WT and SP6AMI bound to the promoter in all instances.

CONCLUSION

ARE cell clones can provide a useful in vitro model to study the mechanism of SP6-mediated amelogenesis imperfecta.

Complementary synaptic distribution of enzymes responsible for synthesis and inactivation of the endocannabinoid 2-arachidonoylglycerol in the human hippocampus

Clinical and experimental evidence demonstrates that endocannabinoids play either beneficial or adverse roles in many neurological and psychiatric disorders. Their medical significance may be best explained by the emerging concept that endocannabinoids are essential modulators of synaptic transmission throughout the central nervous system. However, the precise molecular architecture of the endocannabinoid signaling machinery in the human brain remains elusive. To address this issue, we investigated the synaptic distribution of metabolic enzymes for the most abundant endocannabinoid molecule, 2-arachidonoylglycerol (2-AG), in the postmortem human hippocampus. Immunostaining for diacylglycerol lipase-α (DGL-α), the main synthesizing enzyme of 2-AG, resulted in a laminar pattern corresponding to the termination zones of glutamatergic pathways. The highest density of DGL-α-immunostaining was observed in strata radiatum and oriens of the cornu ammonis and in the inner third of stratum moleculare of the dentate gyrus. At higher magnification, DGL-α-immunopositive puncta were distributed throughout the neuropil outlining the immunonegative main dendrites of pyramidal and granule cells. Electron microscopic analysis revealed that this pattern was due to the accumulation of DGL-α in dendritic spine heads. Similar DGL-α-immunostaining pattern was also found in hippocampi of wild-type, but not of DGL-α knockout mice. Using two independent antibodies developed against monoacylglycerol lipase (MGL), the predominant enzyme inactivating 2-AG, immunostaining also revealed a laminar and punctate staining pattern. However, as observed previously in rodent hippocampus, MGL was enriched in axon terminals instead of postsynaptic structures at the ultrastructural level. Taken together, these findings demonstrate the post- and presynaptic segregation of primary enzymes responsible for synthesis and elimination of 2-AG, respectively, in the human hippocampus. Thus, molecular architecture of the endocannabinoid signaling machinery supports retrograde regulation of synaptic activity, and its similar blueprint in rodents and humans further indicates that 2-AG's physiological role as a negative feed-back signal is an evolutionarily conserved feature of excitatory synapses.

Alteration of adipokines during peripheral blood stem cell mobilization induced by granulocyte colony-stimulating factor

Adipokines, soluble mediators produced by adipocytes, have been shown to play a role in various physiological and pathological conditions. We investigated the involvement of adipokines in granulocyte colony-stimulating factor (G-CSF)-induced mobilization of hematopoietic stem cells in 21 healthy donors. We found that serum visfatin and resistin levels, but not leptin and adiponectin levels, were significantly elevated by G-CSF treatment. G-CSF treatment activated signaling proteins like extracellular signal-regulated kinase and stimulated secretion of visfatin from 3T3-L1 adipocytes. These findings suggest that some adipokines may play a role in G-CSF-induced mobilization of stem cells from the bone marrow into systemic circulation.

The anti-apoptotic role of the unfolded protein response in Bcr-Abl-positive leukemia cells

To define the role of the unfolded protein response (UPR) in leukemogenesis, we investigated UPR activation in the cells expressing the representative oncogene Bcr-Abl (B-A). The expression of UPR-related proteins and mRNAs, namely, X-box-binding protein (XBP1) and glucose-regulated protein 78 (GRP78) was increased in B-A. UPR inhibition using inositol-requiring enzyme 1alpha (IRE1alpha) or activating transcription factor 6 (ATF6) dominant-negative mutants diminished the ability of Bcr-Abl to protect the cells from etoposide- and imatinib-induced apoptosis. We also noted that the expression of UPR-related genes in primary leukemia cells from Philadelphia chromosome (Ph)-positive cells was higher than that in the control by quantitative RT-PCR assay. Thus, our results suggested that UPR is a downstream target of Bcr-Abl and plays an anti-apoptotic role in Ph-positive leukemia cells.

Structure of electrolyte solutions sorbed in carbon nanospaces, studied by the replica RISM theory

The replica RISM theory is used to investigate the structure of electrolyte solutions confined in carbonized polyvinylidene chloride (PVDC) nanoporous material, compared to bulk electrolyte solution. Comparisons are made between the models of electrolyte solution sorbed in the carbonized PVDC material and a single carbon nanosphere in bulk electrolyte solution. Particular attention is paid to the chemical potential balance between the species of the sorbed electrolyte solution and the bulk solution in contact with the nanoporous material. As a result of the strong hydrophobicity of the carbonized PVDC material in the absence of activating chemical groups, the densities of water and ions sorbed in the material are remarkably low compared to those in the ambient bulk solution. The interaction between water molecules and cations becomes strong in nanospaces. It turns out that, in carbon nanopores, a cation adsorbed at the carbon surface is fully surrounded by the hydration shell of water molecules which separates the cation and the surface. Distinctively, an anion is adsorbed in direct contact with the carbon surface, which squeezes a part of its hydration shell out. The tendency increases toward smaller cations, which are characterized as "positive hydration" ions. In the bulk, cations are not hydrated so strongly and behave similarly to anions. The results suggest that the specific capacitance of an electric double-layer supercapacitor with nanoporous electrodes is intimately related to the solvation structure of electrolyte solution sorbed in nanopores, which is affected by the microscopic structure of the nanoporous electrode.

Elevation of serum high-mobility group box 1 protein during granulocyte colony-stimulating factor-induced peripheral blood stem cell mobilisation

High mobility group box 1 (HMGB1) is a non-histone protein involved in maintaining the architecture of chromatin. HMGB1 also acts extracellularly as a cytokine, in processes such as inflammation, cell migration and stem cell recruitment. The involvement of HMGB1 in granulocyte colony-stimulating factor (G-CSF)-induced mobilisation of haematopoietic stem cells was investigated in 21 healthy donors. G-CSF treatment significantly elevated serum HMGB1 levels, which increased from 1.16 +/- 0.86 ng/ml, before treatment, to 31.1 +/- 5.99 ng/ml, after treatment. These findings suggest HMGB1 may play a role during the mobilisation of stem cells from the bone marrow into the systemic circulation.

Visualization of inositol 1,4,5-trisphosphate receptor type III with green fluorescent protein in living cells

Inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular Ca2+ channel that releases Ca2+ into the cytosol and its subcellular distribution is believed to have significant effects on Ca2+ signalling. We constructed a plasmid vector containing full-length rat type 3 IP3R linked to GFP (GFP-IP3R) for expression in mammalian cells. Western blot analyses revealed that the expressed fusion protein contained both GFP and full-length type 3 IP3R. Fluorescence confocal microscopy showed that the fluorescence of GFP-IP3R3 was distributed to reticular network structures, even after cell permeabilization with saponin. We further visualized intracellular membranes with DiOC6, a vital fluorescent marker for intracellular membranes, and provide evidence that the distribution of GFP-IP3R3 overlaps with the distribution of the endoplasmic reticulum. Our results indicate that GFP-IP3R3 can be used to visualize IP3R in living cells, and pave the way for subsequent mutational and functional studies.

Possible mechanisms regulating ATP- and thimerosal-induced Ca(2+) oscillations in the HSY salivary duct cell line

The ATP-induced oscillatory changes in cytosolic Ca(2+) concentration ([Ca(2+)](i)) were analysed in HSY cells, a salivary ductal cell line from human parotid, using a fluorescence ratio imaging system. At concentrations higher than 1 microM, ATP caused sinusoidal [Ca(2+)](i) oscillations due to the periodic release and reuptake of Ca(2+) by intracellular Ca(2+) stores. The phorbol ester 4beta-phorbol 12,13-dibutyrate (PDBu) changed the [Ca(2+)](i) oscillations to a single spike. The inhibitory effect of PDBu on the [Ca(2+)](i) signals was reversed by protein kinase C (PKC) inhibitors such as staurosporine and chelerythrine chloride. However, preincubation of the cells with the PKC inhibitors did not affect the pattern of the ATP-induced [Ca(2+)](i) oscillations. The desensitization of the [Ca(2+)](i) response observed during prolonged stimulation with ATP was also not prevented by the PKC inhibitors. Incubation of HSY cells with the sulphydryl reagent thimerosal, which enhances the sensitivity of inositol 1,4,5-trisphosphate (IP(3)) receptors, caused repetitive Ca(2+) release from intracellular Ca(2+) stores resulting in baseline spikes of [Ca(2+)](i). The thimerosal-induced [Ca(2+)](i) oscillations did not change in the presence of PDBu and the phospholipase C inhibitor U73122. Thus, we could not provide evidence that negative feedback by PKC plays a central role in the regulation of ATP-induced [Ca(2+)](i) oscillations. These results suggest that the [Ca(2+)](i) oscillations, at least the baseline spikes, in HSY cells can be generated without stimulating the formation of IP(3).

[The occurrence of Churg-Strauss syndrome in two patients with remitted asthma]

We report two patients with Churg-Strauss syndrome (CSS) which occurred on the remission stage of bronchial asthma. Case 1 of a 64-year-old woman suffered from asthma in June, 1997, and got relief with treatment. In February, 1998, dysesthesia, pain and severe muscle weakness occurred in the extremities and erythematous rashes appeared on the extremities and back. She was transferred to our hospital on March 3. Peripheral blood eosinophilia was observed and a diagnosis of CSS was made. Eosinophilic tissue infiltration and vasculitis was found in the skin biopsy specimen. She was treated with prednisolone (60 mg/day) with moderate improvement. But the dysesthesia in the extremities, bilateral foot drop and the weakness of the left hand grasping power continued. Case 2 of a 62-year-old woman suffered from asthma in 1995, which improved by treatment. In March 1998, dysesthesia and pain in the lower extremities occurred and progressed. Erythematous rashes appeared on the feet and she was admitted to our hospital in May. Peripheral blood eosinophilia and eosinophilic tissue infiltration in the skin biopsy specimen were observed and a diagnosis of CSS was made. The treatment with prednisolone (60 mg/day) improved the pain but the dysesthesia continued. It is important to know the occurrence of CSS on the remission stage of bronchial asthma.

Clinical pathway for impalpable or small lung lesions treated with coil marking and thoracoscopy

OBJECTIVES

Advances in computed tomography are detecting increasingly impalpable or small pulmonary lesions. We propose a clinical pathway for managing such lesions.

METHODS

We conducted a retrospective study in a community teaching hospital to describe the hospital schedules of 18 patients having 19 lesions 10 mm or less and ground glass attenuation. Under computed tomography, a coil (Complex Helical Fibered Platinum Coil-18) was placed at the proximal side of the lesion. Using thoracoscopy and radiographic fluorography, we conducted partial lung resection targeting the coil the next day, adding lobectomy, if required.

RESULTS

Final diagnosis included primary and metastatic lung cancer (n = 14), atypical adenomatous hyperplasia (n = 1), and benignancy (n = 4). Patients were admitted 2* days before surgery (*Numbers are medians). On postoperative day 3, chest tubes were removed. Epidural analgesia was continued for 5 days. On postoperative day 7, patients were discharged. Their admission charge was a total of yen 979,610.

CONCLUSIONS

The hospital course above may be applied to the clinical pathway for managing impalpable or small lung lesions.

Characterization of the ca2 + response mediated by activation of beta-adrenoceptors in rat submandibular ducts

The Ca2+ signaling mediated by activation of beta-adrenoceptors was studied in a purified preparation of ducts from rat submandibular glands. At concentrations above 1 nM, isoproterenol (ISO) caused a small but significant increase in cytosolic Ca2+ concentration ([Ca2+]i). The ISO-induced increase in [Ca2+]i was completely inhibited by the beta-adrenoceptor antagonist propranolol but not by the alpha-adrenoceptor antagonist phentolamine. Forskolin was able to mimic the Ca2+ response to ISO. These results suggest that the ISO-induced increase in [Ca2+]i in rat submandibular ducts is mediated by an accumulation of cAMP resulting from activation of beta-adrenoceptors. In the absence of extracellular Ca2+, ISO or forskolin caused a transient increase in [Ca2+]i, indicating Ca2+ mobilization from intracellular Ca2+ stores. Further, stimulation with ISO failed to mobilize Ca2+ after the depletion of intracellular Ca2+ stores by phenylephrine or carbachol, suggesting that the cAMP-mediated increase in [Ca2+]i is due to a Ca2+ release from inositol trisphosphate (IP3)-sensitive Ca2+ stores. As ISO did not stimulate a detectable production of IP3, the cAMP-mediated Ca2+ mobilization may be evoked by a mechanism different from activation of phosphoinositide hydrolysis.

Evidence that type I, II, and III inositol 1,4,5-trisphosphate receptors can occur as integral plasma membrane proteins

A number of previous reports have suggested that inositol 1,4, 5-trisphosphate receptors (IP(3)Rs) are present in the plasma membranes of cells. We confirm this directly in the present study by demonstrating that a significant proportion of the IP(3)Rs found in A431 cells, Jurkat cells, and rat parotid acini can be biotinylated by the extracellular application of sulfo-N-hydroxysuccinimide-biotin to intact cells. This labeling cannot be accounted for by the reaction of sulfo-N-hydroxysuccinimide-biotin with intracellular IP(3)Rs since calnexin and the SERCA2 ATPase, both integral membrane proteins of the endoplasmic reticulum, are not labeled under the same experimental conditions. Individual IP(3)R subtypes were detected using subtype-specific antibodies. A431 cells expressed only the type-3 IP(3)R, and 23% of this protein was in the biotinylated (plasma membrane) fraction. Jurkat cells and rat parotid cells expressed all three IP(3)R subtypes. Contrary to earlier results suggesting that only the type-3 IP(3)R might localize to the plasma membrane, we found that significant amounts (5-14%) of all three subtypes could be identified in the biotinylated fractions of Jurkat and rat parotid cells. Our results suggest a role for IP(3)Rs in plasma membrane as well as intracellular membrane function.

Hemopneumothorax and hemoperitoneum in a case with large cell carcinoma of the lung

Hemopneumothorax and hemoperitoneum coincide rarely in nontraumatic cases. Here, a 70-year-old male presented a left axillary lymph node and was diagnosed as having metastatic squamous cell carcinoma. Under the same diagnosis, another lesion developed in the right femur and was resected. One year later, computed tomography detected another tumor in the left adrenal gland. Shortly afterwards, left pneumothorax developed and a chest operation revealed hemopneumothorax due to a ruptured cavitary form of large cell carcinoma. The serum showed a human chorionic gonadotropin-beta level of 1,100 ng/ml. At three-months later, he died of hemoperitoneum. The autopsy demonstrated hepatic metastases and a ruptured adrenal metastasis; microscopy showed marked trophoblastic and squamous cell changes in these organs. This patient was unique in that the rupture of the pulmonary and the adrenal lesions caused clinical manifestation.

Constituents in watercress: inhibitors of histamine release from RBL-2H3 cells induced by antigen stimulation

Histamine release inhibitors in watercress (Nasturtium officinale) were isolated using a monitoring system with antigen-stimulated RBL-2H3 cells. Of the 15 compounds isolated, flavonols and megastigmanes significantly inhibited histamine release. Two flavonols, 3-O-sophorosides of rhamnetin and rhamnazin, were new compounds. To investigate the inhibitory mechanism, the effects of rhamnetin, rhamnetin 3-O-sophoroside and an isolated megastigmane glucoside on the increase in the intracellular free calcium concentration were examined at a concentration providing 60% inhibition of histamine release. The results suggest that these compounds did not affect the calcium influx at that concentration. The structure-activity relationships of the megastigmanes on histamine release were also investigated.

5-hydroxytryptamine induces transient Ca2+ influx through Ni2+-insensitive Ca2+ channels in rat vascular smooth muscle cells

The effects of Ni2+, a non-selective cation channel inhibitor, on 5-hydroxytryptamine (5-HT)- and angiotensin II (Ang II)-induced intracellular Ca2+ dynamics in rat aortic smooth muscle cells were investigated. Ni2+ (1 mM) significantly inhibited the transient increase in intracellular Ca2+ concentration ([Ca2+]i) induced by Ang II (100 nM) in aortic smooth muscle cells, as measured using fura-2. However, Ni2+ did not suppress the transient increase in Ca2+ influx induced by 5-HT (10 microM), while significantly suppressed the sustained increase. Ca2+ influx evoked by high KCl (80 mM), thapsigargin (TG) (1 microM) or depletion of intracellular Ca2+ store was almost completely suppressed by Ni2+. Ni2+ had no effect on 5-HT-induced inositol triphosphate production and Ca2+ release from the intracellular store(s). These results suggest that 5-HT, but not Ang II, induces transient Ca2+ influx through Ni2+-insensitive Ca2+ channels, which are distinguishable from the voltage-dependent or store-operated Ca2+ channels.

Epiphrenic diverticulum composed of airway components attributed to a bronchopulmonary-foregut malformation: report of a case

Bronchopulmonary-foregut malformation (BPFM), defined originally as pulmonary sequestration with or without communication to the esophagus, has been acknowledged to include congenital foregut diverticula. We present herein the case of a 43-year-old woman with a 9-year history of dysphagia, in whom a barium meal examination demonstrated a 2.5-cm epiphrenic diverticulum and several fistulae. A laparotomy was performed and the lower esophagus without communication to the lung was pulled down and resected, followed by an esophagogastrostomy carried out with fundopexy. Since her operation, the patient has been free of symptoms. Histologically, the diverticulum was observed to be lined by stratified squamous cells, but its shape was formed by mural cartilage, smooth muscle cells, and three ciliated-cell cysts. The dysphagia was considered to have been derived from the kinked esophagus created by the rigid diverticulum, being the possible developmental arrest of a supernumerary lung bud. These findings indicate that this case may involve BPFM in the broad sense. Although several cases of bronchogenic cysts located beneath or across the diaphragm have been reported as a subgroup of BPFM, congenital epiphrenic diverticula has rarely been described.

Isoproterenol potentiates alpha-adrenergic and muscarinic receptor-mediated Ca2+ response in rat parotid cells

The effects of the cAMP pathway on the Ca2+ response elicited by phospholipase C-coupled receptor stimulations were studied in rat parotid cells. Although 1 microM isoproterenol (Iso) itself had no effect on the cytosolic Ca2+ concentration, the pretreatment with Iso potentiated Ca2+ responses evoked by phenylephrine. The potentiating effect of Iso was attributed to a shifting of the concentration-response curves of phenylephrine to the left and an increase in the maximal response. Half-maximal potentiation occurred at 3 nM Iso. Iso also potentiated the Ca2+ response elicited by carbachol. The potentiating effect of Iso was mimicked by forskolin (10 microM) and dibutyryl adenosine 3',5'-cyclic monophosphate (2 mM) and was blocked by 10 microM H-89. Iso potentiated the phenylephrine-induced Ca2+ response in the absence of extracellular Ca2+, but Iso did not increase the inositol trisphosphate (IP3) production induced by phenylephrine. These results suggest that the potentiation of the Ca2+ response can be attributed to a sensitization of IP3 receptors by cAMP-dependent protein kinase.

Signet ring cell adenoma of the thyroid with mucin predominance

A 22-year-old male presented with a 1-year history of a right anterior neck mass. He did not have gastrointestinal cancer. Laboratory examination revealed an elevated serum thyroglobulin level of 120 ng/mL. The neck lesion showed poor uptake on 99mTc scan, but enhanced uptake on 201T1 scan. The patient underwent a hemithyroidectomy; the cut surface of the 7 x 3.5 cm lesion was solid and tanned orange. Postoperatively the serum thyroglobulin level decreased to 26 ng/mL. Microscopy of the tumor showed signet ring cells and microfollides, both of which were positive for mucicarmin and alcian Blue. A small percentage of the follicles were positive for thyroglobulin and periodic acid-Schiff. Our literature search detected 18 patients with signet ring cell lesions positive for thyroglobulin, but none had characteristics similar to ours showing predominance of mucin and poor staining for thyroglobulin.

Interaction of Gli2 with CREB protein on DNA elements in the long terminal repeat of human T-cell leukemia virus type 1 is responsible for transcriptional activation by tax protein

The long terminal repeat (LTR) of human T-cell leukemia virus type 1 (HTLV-1) has two distinct DNA elements, one copy of TRE2S and three copies of a 21-bp sequence that respond to the viral trans-activator protein, Tax. Either multiple copies of the 21-bp sequence or a combination of one copy each of TRE2S and 21-bp sequence is required for efficient trans activation by Tax. In the trans activation of multiple copies of 21-bp sequence, CREB/ATF protein plays an essential role in forming a complex with Tax. To understand the role of TRE2S in trans activation of one copy of 21-bp sequence, we examined protein binding to the DNA elements by DNA affinity precipitation assay including Gli2 protein binding to TRE2S and CREB protein binding to 21-bp sequence. Binding of CREB to a DNA probe containing both elements, TRE2S-21bp probe, was dependent on Gli2 protein under restricted conditions and was enhanced in a dose-dependent fashion by the binding of Gli2 protein to the same probe. Mutation in either element abolished the efficient binding of CREB. A glutathione S-transferase fusion protein of a fragment of Gli2 was able to bind to CREB. Therefore, Gli2-CREB interaction on the DNA probe is proposed to stabilize CREB binding to DNA. Tax can bind to CREB protein on the DNA; therefore, stabilization of DNA binding of CREB results in more recruitment of Tax onto DNA. Conversely, Tax increased the DNA binding of CREB, although it had almost no effect on the binding of Gli2. These results suggest that Gli2 binds to the DNA element and interacts with CREB, resulting in more recruitment of Tax, which in turn stabilizes DNA binding of CREB. Similar cooperation of the protein binding to TRE2S-21bp probe was also observed in nuclear extract of an HTLV-1-infected T-cell line. Consistent with the Gli2-CREB interaction on the DNA elements, Tax-mediated trans activation was dependent on the size of the spacer between TRE2S and 21-bp sequence. The effective sizes of the spacer suggest that TRE2S in the LTR would cooperate with the second and third copies of the 21-bp sequence and contribute to trans activation of the viral gene transcription.

[Inhibitory effect of green tea infusion of hepatotoxicity]

We first showed a drinking of green tea infusion can inhibit chemically induced possible hepatic tissue damages in animal experiments, although it has been shown that oral administration of green tea extract can inhibit some organ toxicities. In this review, our data are summarized and a possibility of the effectiveness in humans is discussed. Male rats or mice in the series of experiments were given 2% green tea infusion as a drinking water 1 or 2 weeks before the chemical treatment and until the termination. In the study of rats, green tea effectively inhibited the hepatotoxicity induced by a single intraperitoneal injection or by repeated gavage administration of 2-nitropropane, and a single intraperitoneal injection of galactosamine. However, any possible effects were not observed when green tea was given, on the hepatotoxicity by a single or repeated gavage administration of carbon tetrachloride. In the study of mice, green tea inhibited the hepatotoxicity induced by administration of pentachlorophenol in diet. In conclusion, 2% green tea infusion can prevent the hepatotoxicity by at least some chemicals in experimental animals. It is inferred that the amount of green tea taken by animals in this experiment might be equivalent to the daily intake in Japanese general population, by calculation based on the content of epigallocatechin gallate, a major component of green tea, and the species differences between experimental animals and humans, suggesting the preventive effectiveness in humans.

Protective effects of green tea on hepatotoxicity, oxidative DNA damage and cell proliferation in the rat liver induced by repeated oral administration of 2-nitropropane

To evaluate the benefit of green tea in mitigating hazards caused by repeated exposure of 2-nitropropane (2NP), we examined the effects of the tea on toxic indices, oxidative DNA damage and cell proliferation in the liver of 2NP-treated rats. Male Fischer 344 rats were administered, by gastric intubation, a total of six doses of 60 mg/kg 2NP(L), or alternatively two doses of 90 mg/kg and then four doses of 120 mg/kg 2NP(H) during 2 weeks. Green tea infusion was given to the rats as drinking water 1 week before the 2NP treatments and throughout the experiment. Significant elevation of hepatotoxic indices was evident in the 2NP(H)-treated group, such as an increase of serum glutamic-oxaloacetic transaminase (GOT) activity and of hepatic lipid peroxidation, together with a decrease in hepatic glycogen and serum triglyceride, and degenerative changes in the hepatocytes. A dose-related increase was observed in oxidative DNA damage and cell proliferation in the liver. Green tea effectively inhibited all of above changes induced by 2NP treatment, suggesting that tea intake may be effective for preventing the hepatic injuries after chronic exposure to 2NP.

Activation of beta-adrenoceptors does not cause any change in cytosolic Ca2+ distribution in rat parotid acinar cells

The effects of the beta-adrenoceptor agonist isoproterenol on the distribution of cytosolic Ca2+ concentrations were studied with digital imaging microscopy in fura-2-loaded rat parotid acinar cells. At concentrations < 10 microM, isoproterenol did not cause any measurable change in cytosolic Ca2+ concentration ([Ca2+]i). Monitoring of [Ca2+]i in selected areas of the acinar cells failed to show that stimulation with isoproterenol causes a localized rise in [Ca2+]i at the apical region close to the lumen. As the maximum response of amylase exocytosis is observed at 0.1 or 1 microM isoproterenol [Tanimura, A., Matsumoto, Y., Tojyo, Y., 1990. Evidence that isoproterenol-induced Ca2+-mobilization in rat parotid acinar cells is not mediated by activation of beta-adrenoceptors. Biochim. Biophys. Acta, 1055, pp. 273-277], the data obtained here indicate that the isoproterenol-induced amylase exocytosis is not accompanied by Ca2+ mobilization. The high concentration (100 microM) of isoproterenol caused a small but significant increase in [Ca2+]i, particularly in the apical region. This response was completely attenuated by the alpha-adrenoceptor antagonist phentolamine, but not by the beta-adrenoceptor antagonist propranolol, indicating that the isoproterenol-induced increase in [Ca2+]i resulted from an activation of alpha-adrenoceptors. Further, the effect of cyclic AMP on Ca2+ release from intracellular Ca2+ stores was studied in saponin-permeabilized acinar cells using the lipophilic Ca2+ indicator Calcium Green C18. Cyclic AMP had no effect on the Ca2+ release, while the same acinar cells responded strongly to inositol 1,4,5-trisphosphate. This result does not support the hypothesis that cyclic AMP directly stimulates Ca2+ mobilization in rat parotid acinar cells.

Analysis of spatial and temporal characteristics of Ca2+ release in permeabilized parotid cells

Ca2+ waves and oscillations have been observed during stimuli that generate inositol 1,4,5-trisphosphate (IP3) in several exocrine cells, including rat parotid acinar cells. Although a model has been proposed to explain the mechanism of the Ca2+ wave, there exists no direct evidence to prove the model's validity. Analysis with a permeabilized cell system provides direct information about the properties of Ca2+ stores and Ca2+ release channels. We summarize here the experimental techniques that may be used to elucidate the spatial and temporal regulation of Ca2+ in a single permeabilized cell. The future applications of these methods and the possible mechanisms of the Ca2+ wave are also discussed.

Polarized Ca2+ release in saponin-permeabilized parotid acinar cells evoked by flash photolysis of 'caged' inositol 1,4,5-trisphosphate

In exocrine acinar cells, agonist stimulation results in a polarized Ca2+ signal, termed the 'Ca2+ wave', that propagates from the apical pole towards the basolateral region. We attempted to detect the inositol 1,4,5-trisphosphate (InsP3)-induced Ca2+ wave in saponin-permeabilized rat parotid acinar cells using a digital imaging system. The permeabilized acinar cells were labelled with the membrane-bound Ca2+ indicator Calcium Green C18 to detect changes in Ca2+ concentration adjacent to the membrane of intracellular organelles. Application of InsP3 was made by the photolysis of InsP3 P4(5)-1-(2-nitrophenyl)ethyl ester (caged InsP3) to expose simultaneously all regions of the permeabilized acinar cells to InsP3. The increase in fluorescence ratio following the photolysis of 0.5 microM caged InsP3 started at the apical region of the acinar cells within 0.1 s and spread towards the basolateral region, indicating that Ca2+ release from intracellular Ca2+ stores was initially evoked at the apical region. Pretreatment with thapsigargin, an inhibitor of endoplasmic reticulum Ca2+ pumps, failed to prevent the InsP3-induced Ca2+ wave, suggesting that the generation of the Ca2+ wave is not attributed to the polarized distribution of the Ca2+ pumps. The photolysis of a high concentration (10 microM) of caged InsP3 caused a homogeneous increase in the fluorescence ratio throughout the cells, indicating that all regions of intracellular Ca2+ stores similarly responded to the high concentration of InsP3. The present study is the first demonstration of the InsP3-induced Ca2+ wave in permeabilized exocrine acinar cells. The result provides fresh evidence that the apical region contains elements of intracellular Ca2+ stores particularly sensitive to InsP3 and that the Ca2+ wave results from a polarized distribution of InsP3-sensitive Ca2+ stores.

Pneumothorax due to hemangiopericytoma metastasis from the thigh

A 25-year-old female had malignant hemangiopericytoma of the right thigh resected. Three years later, right pneumothorax developed, necessitating a thoracotomy. A 3-cm bulla was discovered on the lower right pulmonary lobe and was subsequently resected. Microscopy showed tumor cells which were positive for actin, but negative for epithelial membrane antigen, vimentin, and factor VIII-related antigen--features compatible with those of the thigh. The patient has been free of the disease for five years. Pertinent literature reveals similar cases with hemangioendothelioma but offers few reports on pneumothorax caused by metastatic hemangiopericytoma.

Imaging of quantal calcium release in the inositol 1,4,5-trisphosphate-sensitive organelles of permeabilized HSY cells

The spatial characteristics of inositol 1,4,5-trisphosphate (IP3)-induced quantal Ca2+ release were examined by imaging Ca2+ concentrations within Ca2+ stores ([Ca2+]L) in permeabilized HSY cells. The image of mag-fura-2 fluorescent ratio with dual excitation (344 nm/360 nm) demonstrated that a sequential application of different concentrations of IP3 (0.1, 0.3, 10 microM) resulted in a stepwise decrease in the ratio at all regions of the cytoplasm. This change in the ratio suggests that the stepwise decrease in [Ca2+]L is associated with the quantal Ca2+ release. To monitor the change in [Ca2+]L within a single organelle, IP3-dependent changes in the mag-fura-red fluorescence of permeabilized cells were studied by confocal microscopy. Applications of increasing concentrations of IP3 caused a stepwise increase in fluorescence within ER-like reticulum structures of the cytoplasm. This finding suggests that the [Ca2+]L in a single Ca2+ store was not depleted by submaximal concentrations of IP3, and supports the steady-state model of quantal Ca2+ release.

Digital imaging of intracellular Ca2+ signaling in rat parotid acinar cells

Utilizing digital imaging microscopy, the receptor-mediated changes in cytosolic Ca2+ concentration ([Ca2+]i) were studied in fura-2-loaded rat parotid acinar cells. The increase in [Ca2+]i induced by carbachol was initiated in the apical pole of the acinar cells and then spread as a Ca2+ wave toward the basolateral region. A similar polarization of Ca2+ signal was observed when the acinar cells were stimulated with substance P or phenylephrine. As the microsomal Ca2+-ATPase inhibitor thapsigargin did not produce a Ca2+ wave, activation of phosphoinositide hydrolysis is probably essential to trigger the Ca2+ wave. Stimulation with 1 microM isoproterenol, a concentration which causes the maximum release of amylase, had no effect on [Ca2+]i. Extracellular ATP (0.5 mM) induced a homogeneous increase in [Ca2+]i throughout the cells in the presence of extracellular Ca2+ but did not change [Ca2+]i in the absence of extracellular Ca2+, indicating that the ATP-induced rise in [Ca2+]i, is due to Ca2+ entry.

Cloning of novel isoforms of the human Gli2 oncogene and their activities to enhance tax-dependent transcription of the human T-cell leukemia virus type 1 genome

The expression of human T-cell leukemia virus type 1 (HTLV-1) is activated by interaction of a viral transactivator protein, Tax, and cellular transcription factor, CREB (cyclic AMP response element binding protein), which bind to a 21-bp enhancer in the long terminal repeats (LTR). THP (Tax-helping protein) was previously determined to enhance the transactivation by Tax protein. Here we report novel forms of the human homolog of a member of the Gli oncogene family, Gli2 (also termed Gli2/THP), an extended form of a zinc finger protein, THP, which was described previously. Four possible isoforms (hGli2 alpha, beta, gamma, and delta) are formed by combinations of two independent alternative splicings, and all the isoforms could bind to a DNA motif, TRE2S, in the LTR. The longer isoforms, alpha and beta, were abundantly expressed in various cell lines including HTLV-1-infected T-cell lines. Fusion proteins of the hGli2 isoforms with the DNA-binding domain of Gal4 activated transcription when the reporter contained a Gal4-binding site and one copy of the 21-bp sequence, to which CREB binds. This activation was observed only in the presence of Tax. The 21-bp sequence in the reporter was also essential for the activation. These results suggest that simultaneous binding of hGli2 and CREB to the respective sites in the reporter seems to be critical for Tax protein to activate transcription. Consequently, it is probable that the LTR can be regulated by two independent signals through hGli2 and CREB, since the LTR contains the 21-bp and TRE2S sequences in the vicinity.

Effect of 5-hydroxytryptamine on intracellular calcium dynamics in cultured rat vascular smooth muscle cells

The present study elucidated the precise mechanism of 5-hydroxytryptamine (5-HT)-induced increase of intracellular Ca2+ concentration ([Ca2+]i) in cultured vascular smooth muscle cells isolated from rat aortic media. [Ca2+]i was measured using fluorescent Ca2+ indicator, fura-2. 5-HT caused a dose-dependent increase in [Ca2+]i, which was completely inhibited by ketanserin. alpha-Methyl-5-HT had an equipotent effect to 5-HT. Diltiazem at 10 microM partially suppressed the 5-HT-induced increase in [Ca2+]i. 5-HT also augmented Mn2+ influx, when monitored by Mn2+ quenching of fura-2 fluorescence. When extracellular Ca2+ (1.3 mM) was removed, a decrease in resting level and a small, transient increase in [Ca2+]i were observed. 5-HT stimulation also induced an increase in the production of inositol triphosphate. 5-HT-induced increase in [Ca2+]i was significantly, but partially inhibited by staurosporin and H-7. Phorbol 12-myristate 13-acetate induced an increase in [Ca2+]i, which was abolished by removal of extracellular Ca2+. 5-HT-induced increase in [Ca2+]i was not affected by the pretreatment with pertussis toxin (PTX), and was not accompanied by a change in cyclic AMP content. These results suggest that, in cultured rat aortic smooth muscle cells, 5-HT increases [Ca2+]i via 5-HT2 receptor subtype by inducing influx of extracellular Ca2+ partially through L-type voltage-dependent Ca2+ channel, as well as by mobilizing Ca2+ from its intracellular stores. Activation of protein kinase C may be positively involved in the regulatory mechanism of Ca2+ influx, but PTX-sensitive G protein and cyclic AMP seem to be not involved.

Imaging of calcium release in inositol 1,4,5-trisphosphate-sensitive internal stores in permeabilized HSY cells using fluorescent indicators

We described methods for imaging the IP3-induced Ca2+ release in Ca2+ storage organelles. IP3-induced changes in Ca2+ concentrations within Ca2+ stores ([Ca2+]L) in permeabilized HSY cells were monitored using the low affinity Ca2+ indicators, mag-fura-2 and mag-fura-red. The ratio images of mag-fura-2 were used to estimate the [Ca2+]L in the store. The apparent [Ca2+]L was 300-1000 microM at the cell periphery, whereas the [Ca2+]L in the cytoplasm around the nucleus was 70-150 microM. The [Ca2+]L throughout the cytoplasm was reduced by the application of 10 microM IP3 to 30-70 microM, and could be largely recovered after removal of IP3. The structure of IP3-sensitive Ca2+ stores was investigated by confocal microscopy using mag-fura-red. An IP3-induced increase in fluorescence was observed in the ER-like network and reticulum structures of the cytoplasm, and also in the nuclear envelope, suggesting that these organelles serve as IP3-sensitive Ca2+ stores. An analogous localization of the network and tubular elements of the ER was also demonstrated by electron microscopy. These observations suggest that these fluorescence techniques are useful to study the correlation between the distribution and function of Ca2+ stores.

Imaging of intracellular Ca2+ waves induced by muscarinic receptor stimulation in rat parotid acinar cells

Changes in cytosolic Ca2+ concentration ([Ca2+]i) following muscarinic receptor stimulation were studied with digital imaging microscopy in small clusters of Fura-2 loaded rat parotid acinar cells. In the absence of extracellular Ca2+, the increase in [Ca2+]i evoked by a high concentration (10 microM) of carbachol (CCh) was initiated in the apical pole of the acinar cells about 0.4 s after stimulation and then rapidly spread as a Ca2+ wave toward the basolateral region. The [Ca2+]i reached the maximum high level throughout the cells 1-2 s after stimulation. As Ca2+ was eliminated from the extracellular medium, the Ca2+ wave was a result of Ca2+ release from intracellular stores. The magnitude and velocity of the Ca2+ wave decreased with decreasing concentration of CCh, and the increase in [Ca2+]i induced by low CCh concentrations (< or = 0.5 microM) was always larger in the apical region of acinar cells than in the basal region. The Ca2+ wave was also observed in isolated single acinar cells, indicating that the maintenance of acinar structure is not essential for the development of the Ca2+ wave. Thapsigargin (ThG), an inhibitor of the endoplasmic reticulum Ca2+ pump, caused a slow and homogeneous increase in [Ca2+]i throughout the cells. Addition of ThG after CCh, or addition of CCh after ThG, did not stimulate further increases in [Ca2+]i, suggesting that the inositol-1,4,5-trisphosphate (InsP3) and ThG-sensitive Ca2+ stores overlap in parotid acinar cells. The present study supports the hypothesis that formation of InsP3 is essential to trigger the Ca2+ wave and that the development of the Ca2+ wave may be attributed to regional differences in InsP3 sensitivity of Ca2+ stores. The agonist-induced Ca2+ wave is probably a general phenomenon in exocrine acinar cells.

Monitoring of Ca2+ release from intracellular stores in permeabilized rat parotid acinar cells using the fluorescent indicators Mag-fura-2 and calcium green C18

The operation of intracellular Ca2+ stores in saponin-permeabilized rat parotid acinar cells was studied by monitoring the Ca2+ concentration within organelles loaded with the low affinity Ca2+ indicator Mag-fura-2. Inositol 1, 4, 5-trisphosphate (InsP3) caused a decrease in the Mag-fura-2 ratio in a dose-dependent manner, and this effect was reversed by a removal of InsP3 or by an addition of the InsP3 receptor antagonist heparin. The changes in Mag-fura-2 ratio indicate the Ca2+ release from InsP3-sensitive Ca2+ stores and Ca2+ re-uptake into the stores in permeabilized acinar cells. The decrease in Mag-fura-2 ratio induced by InsP3 was observed at all regions of the acinar cells, suggesting that the InsP3-sensitive Ca2+ stores are located throughout the cells. The InsP3-induced Ca2+ release was also monitored using the membrane-bound Ca2+ indicator Calcium Green C18 which is sensitive to the changes in Ca2+ concentration immediately adjacent to the membrane of intracellular Ca2+ stores. InsP3 caused a large increase in the Calcium Green C18 fluorescence reflecting Ca2+ release from the stores. The Ca2+ pump inhibitor thapsigargin (ThG) itself had little or no effect on the Mag-fura-2 ratio or Calcium Green C18 fluorescence, but combined application of ThG with a low concentration of InsP3 evoked a significant decrease in the Mag-fura-2 ratio. This result supports the hypothesis that the ThG-induced Ca2+ release is due to InsP3-sensitive Ca2+ release which is mediated by the resting levels of InsP3. Further, none of cyclic ADP-ribose, caffeine or ryanodine changed the Mag-fura-2 ratio and Calcium Green C18 fluorescence, leading to the assumption that the ryanodine-sensitive Ca2+ stores are minor in rat parotid acinar cells.

[Specific modulation of vascular smooth muscle cell functions by docosahexaenoic acid]

There are increasing evidences that fish oil-enriched diets attenuate the progression of several types of human and experimental renal, intestinal and cardiovascular disorders including hypertension. Docosahexaenoic acid (DHA) may be one of the active biological component. We previously reported that dietary DHA suppressed the progression of hypertension in stroke-prone spontaneously hypertensive rats (SHRSP). The purpose of this study was to clarify the in vitro effect of DHA on vascular smooth muscle cell functions such as cell growth, hypertrophy, NO release, and intracellular Ca+2 dynamics which involves in the regulatory mechanisms of vascular tone. Addition of DHA to the culture medium of aortic smooth muscle cells isolated from SHRSP and normotensive Wistar Kyoto rats (WKY) had no significant effects on the cell growth, and cell hypertrophy induced by angiotensin II as measured by flow cytometer. DHA did not have a significant effect on interleukin-1 beta (10 ng/ml)-induced nitric oxide release from smooth muscle cells of SHRSP. However, the treatment of smooth muscle cells with DHA (30 microM) for 2 days significantly suppressed the increase in the intracellular Ca2+ concentration induced by 5-hydroxytryptamine, angiotensin II, depolarizing concentration of KCl, but not by thapsigargin. This suppression seems to be due to the suppression of Ca2+ influx, as determined by Mn2+ influx experiment. These results suggest that DHA specifically suppresses receptor-mediated Ca2+ influx in smooth muscle cells. This may be one of the mechanisms by which dietary DHA prevents the development of hypertension in SHRSP.

[New aspects of the mechanism of Ca2+ entry in non-excitable cells]

The capacitative Ca2+ entry has been accepted to play a crucial role in Ca2+ signaling in non-excitable cells, and the mechanisms linking the depletion of intracellular Ca2+ stores to the activation of Ca2+ entry are presently the subject of intensive investigation. There are two hypotheses to explain the molecular mechanism of capacitative Ca2+ entry. One is that a diffusible second messenger released from intracellular Ca2+ stores may activate a Ca2+ channel at the plasma membrane. Numerous molecules, including CIF, cGMP, arachidonic acid, and a small G-protein, are proposed as the candidates for the diffusible messenger. In addition, the capacitative Ca2+ entry has been suggested to be modulated by protein phosphorylation/dephosphorylation. Another hypothesis is termed the "conformational coupling model". This model suggests that information between the IP3 receptor and a plasma membrane Ca2+ channel may be transferred directly through conformational protein-protein interactions. The plasma membrane Ca2+ channel involved in the capacitative Ca2+ entry is still neither purified nor cloned, but recent studies suggest that the mammalian homologue of the Drosophila protein Trp may function as a capacitative Ca2+ entry channel.

A novel inhibitor of bacterial endotoxin derived from cinnamon bark

A substance that inhibits the activity of bacterial endotoxin (LPS) was found in cinnamon bark. The inhibitor, extracted from dry cinnamon bark with 67% ethanol/water, was purified by using Limulus gelation activity as an indicator of endotoxin activity. The inhibitor suppressed the activity of the LPS when it was mixed with the inhibitor prior to the assay. The reduction of the LPS activity depended on the concentration of both the inhibitor and LPS when mixed, and also on the incubation time. The inhibitor suppressed the activity of all LPS and lipid A preparations tested regardless of the origin of the bacteria. The inhibitor alone did not affect the Limulus system. These results indicate that the inhibition was caused by direct interaction of the inhibitor with the LPS molecule. Furthermore the inhibitor abrogated the pyrogenicity of the LPS. Although it is uncertain whether the inhibitor actually plays a role in the defense mechanism in cinnamon bark, this is the first report that an inhibitor of bacterial endotoxin exists in a plant.

Effects of extracellular ATP on cytosolic Ca2+ concentration and secretory responses in rat parotid acinar cells

At concentrations >50 microM, extracellular ATP dose-dependently increased cytosolic Ca2+ concentration ([Ca2+]i) via activation of P(2Z) purinoceptors in rat parotid acinar cells. This increase in [Ca2+]i is primarily due to entry of Ca2+ from the extracellular medium. Inositol trisphosphate formation and Ca2+ release from intracellular Ca2+ stores were slightly stimulated by ATP. These responses seem to result from the activation of a P2 purinoceptor subtype different from P(2Z) because the maximum responses were induced by much lower concentrations ( <0.25 mM) of ATP than those (> 1 mM) required to produce the maximum activation of Ca2+ entry. ATP did not stimulate amylase release, supporting the view that an increase in [Ca2+]i is not a sufficient stimulus. In addition, ATP evoked a marked K+ release in the presence and absence of extracellular Ca2+, while in carbachol-stimulated cells. only a transient release of K+ was observed in the absence of extracellular Ca2+. The ATP-induced K+ release may be mediated by a mechanism independent of the opening of the Ca(2+)-sensitive K+ channels.

Evidence that up-regulation of the parotid Na(+)-K(+)-2Cl- cotransporter by hypertonic shrinkage is not duplicated by isotonic shrinkage

The application of Ca2+ mobilizing secretagogues to rat parotid acini results in a significant decrease in cell volume (15-30%) due to isotonic salt loss. It is often assumed that the effects of such an isotonic volume decrease can be mimicked by anisotonic cell shrinkage. We demonstrate that the Na(+)-K(+)-2Cl- cotransporter in these cells is up-regulated by Ca2+ mobilizing secretagogues as well as by cell shrinkage in hypertonic media. However, we find that although the protein kinase inhibitors staurosporine (0.3 microM) and K252a (0.6 microM) significantly blunt the latter up-regulation, they are without effect on the former. These observations suggest that hypertonic and isotonic shrinkage do not result in the activation of the same intracellular signalling pathways, and indicate that anisotonic volume perturbations may not provide good experimental models of physiologic isotonic volume changes.

Inositol 1,4,5-trisphosphate-dependent oscillations of luminal [Ca2+] in permeabilized HSY cells

Oscillations in intracellular Ca2+ concentration ([Ca2+]i) are thought to play an important role in phosphoinositide-linked Ca2+ signaling events. We demonstrate corresponding inositol 1,4, 5-trisphosphate (IP3)-dependent oscillations of Ca2+ concentration within the lumen of the IP3-sensitive stores ([Ca2+]L) of saponin-permeabilized HSY cells by monitoring [Ca2+]L with the fluorescent Ca2+ indicator Mag-fura-2. The associated openings and closings of the IP3-sensitive Ca2+ release channel were detected via quenching of Mag-fura-2 fluorescence due to the entry of Mn2+, a Ca2+ surrogate, into the stores. Evidence for complimentary Ca2+ oscillations at the external surface of the stores was provided by the membrane-bound Ca2+ probe Calcium Green C18. The permeabilization of saponin-treated HSY cells to macromolecules was confirmed by demonstrating that permeabilized cells readily took up and lost (t1/2 approximately 46 s) a fluorescently tagged 70-kDa dextran. Our results impose a number of constraints on possible mechanisms for [Ca2+]i oscillations. In addition, they support recent proposals that [Ca2+]i oscillations arise directly from the (biphasic) effects of Ca2+ itself on IP3-sensitive Ca2+ channel activity.