Role of actin in the cAMP-dependent activation of sodium/glucose cotransporter in renal epithelial cells

We examined whether actin filaments are involved in the cAMP-dependent activation of a high affinity sodium/glucose cotransporter (SGLT1) using epithelial expression systems. The expression of enhanced green fluorescent protein-tagged SGLT1 (EGFP-SGLT1) in Madin-Darby canine kidney (MDCK) cells was revealed by Western blotting and confocal laser microscopy. 8-Br-cAMP, a membrane permeable cAMP analog, enhanced [¹⁴C]-α-methyl glucopyranoside ([¹⁴C]-AMG) uptake. Both basal and 8-Br-cAMP-elicited [¹⁴C]-AMG uptakes were inhibited by N-(2{[3-(4-bromophenyl)-2-propenyl]-amino}-ethyl)-5-isoquinolinesulfonamide (H-89), a protein kinase A inhibitor, and cytochalasin D, an actin filament formation inhibitor. Furthermore, cytochalasin D inhibited the distribution of EGFP-SGLT1 at the apical surface. These results suggest that the EGFP-SGLT1 protein is functionally expressed in the apical membrane of MDCK cells, and is up-regulated by a cAMP-dependent pathway requiring intact actin filaments.     

Targeting Interleukin-6: All the Way to Treat Autoimmune and Inflammatory Diseases

Interleukin (IL)-6, a cytokine featuring redundancy and pleiotropic activity, contributes to host defense against acute environmental stress, while dysregulated persistent IL-6 production has been demonstrated to play a pathological role in various autoimmune and chronic inflammatory diseases. Targeting IL-6 is thus a rational approach to the treatment of these diseases. Indeed, clinical trials of tocilizumab, a humanized anti-IL-6 receptor antibody have verified its efficacy and tolerable safety for patients with rheumatoid arthritis, Castleman''s disease and systemic juvenile idiopathic arthritis, resulting in approval of this innovative biologic for treatment of these diseases. Moreover, a considerable number of case reports and pilot studies of off-label use of tocilizumab point to the beneficial effects of tocilizumab for a variety of other phenotypically different autoimmune and chronic inflammatory diseases. Elucidation of the source of IL-6 and of mechanisms through which IL-6 production is dysregulated can thus be expected to lead to clarification of the pathogenesis of various diseases.     

Effects of delayed mating on preimplantation embryos in spontaneously ovulated mice

The effects of delayed mating on mouse preimplantation embryos (78 ± 1 hours) were studied by setting up different mating periods in relation to the estimated time of spontaneous ovulation. Copulation occurred even in the late morning and early afternoon after the night of spontaneous ovulation. However, females mated in the early afternoon had no viable embryos at the time of laparotomy. Although embryonic development was not affected in the groups mated 6 or 10 hours after estimated ovulation, the percentage of degenerated embryos was increased in these groups. These results suggest that prolonged intervals between the estimated time of ovulation and mating have some deleterious effects on preimplantation embryos.     

Hyperthermic treatment of chromomycosis with disposable chemical pocket warmers

A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan.     

Nesting behavior of the semi-aquatic spider wasp,Anoplius eous,which transports its prey on the surface film of water (Hymenoptera,Pompilidae)

Anoplius eous Yasumatsu (Hymenoptera, Pompilidae) exhibits some outstanding nesting behavior. Females excavate a unicellular or multicellular nest in wet ground, or dig a single-celled nest in rotten wood, or build clustered mud cells in narrow spaces between walls of such substances as wood or vinyl sheets. The latter nest-type has been unknown within the subfamily Pompilinae. Females prepare a nest-cell before hunting, and construct it further after hunting, leaving the prey near the nest (behavior-formula: IVPTIOC). They transport their prey backward on the ground, grasping it in their mandibles by any part of the legs, and forward on the surface film of water or on the ground, grasping it by the middle part of the 1st or 2nd legs. Their only prey is the adult female semi-aquatic spider,Pardosa pseudoannulata (Lycosidae). These nesting and provisioning behavior patterns are compared with those of other pompilids. The position of the present species in the behavioral evolution of the Pompilidae is suggested.     

Solution Radioactivated by Hadron Radiation Can Increase Sister Chromatid Exchanges

When energetic particles irradiate matter, it becomes activated by nuclear reactions. Radioactivation induced cellular effects are not clearly understood, but it could be a part of bystander effects. This investigation is aimed at understanding the biological effects from radioactivation in solution induced by hadron radiation. Water or phosphate buffered saline was activated by being exposed to hadron radiation including protons, carbon- and iron-ions. 1 mL of radioactivated solution was transferred to flasks with Chinese hamster ovary (CHO) cells cultured in 5 mL of complete media. The induction of sister chromatid exchanges (SCE) was used to observe any increase in DNA damage responses. The energy spectrum and the half-lives of the radioactivation were analyzed by NaI scintillation detector in order to identify generated radionuclides. In the radioactivated solution, 511 keV gamma-rays were observed, and their half-lives were approximately 2 min, 10 min, and 20 min. They respectively correspond to the beta+ decay of ¹⁵O, ¹³N, and ¹¹C. The SCE frequencies in CHO cells increased depending on the amount of radioactivation in the solution. These were suppressed with a 2-hour delayed solution transfer or pretreatment with dimethyl sulfoxide (DMSO). Our results suggest that the SCE induction by radioactivated solution was mediated by free radicals produced by the annihilated gamma-rays. Since the SCE induction and DMSO modulation are also reported in radiation-induced bystander effects, our results imply that radioactivation of the solution may have some contribution to the bystander effects from hadron radiation. Further investigations are required to assess if radioactivation effects would attribute an additional level of cancer risk of the hadron radiation therapy itself.     

In vitro immune response to the 2,4,6-trinitrophenyl determinant in aged C57BL/6J mice:changes in the humoral immune response to, avidity for the TNP determinant and responsiveness to LPS effect with aging.

An in vitro anti-TNP response of the spleen cells from aged C57BL/6J mice showed approximately 4-fold less PFC than did that from young adult mice. Anti-theta serum-treated young spleen cells gave an anti-TNP response that was definitely greater than the response of the anti-theta serum-treated aged spleen cells in the presence of the exogenous activated thymus cells as helper cells. These results suggest that the deficits in B cells may be partly responsible for the imparied anti-TNP response of the aged spleen cells. To examine further the capacity of stem cells in the bone marrow to generate B cells responsible for anti-TNP response in the spleen, we injected i.v. 1.5 to 2.0 times 10(7) bone marrow cells from young or aged mice into lethally irradiated syngeneic recipients that had previously been thymectomized. Four to 6 weeks later, 10(7) spleen cells from the two groups of these recipient mice were immunized with TNP-SRBC in the presence of the exogenous activated thymus cells and assayed for anti-TNP PFC. The response of the aged marrow-derived B cells was approximately one-half of that of the young marrow-derived B cells.The avidity for TNP determinant of the antibodies produced by the PFC was determined by the plaque-inhibition technique. The avidity of the antibodies produced by the aged mice was approximately 33 times lower than that by the young mice. Anti-TNP response of the young spleen cells were markedly enhanced by the addition of LPS to the cultures, whereas no or little enhancement of the response was induced in the aged spleen cells even in the presence of high concentration of LPS. In contrast, DNA synthesis of both the young and aged spleen cells was comparably stimulated by 1 mug/ml and 10 mug/ml of LPS, however, it was rather less in the aged spleen cells at a concentration of 100 mug/ml. Mechanisms responsible for the changes in avidity and responsiveness to LPS with aging are discussed.     

Changes in Volatile C6-Aldehydes Emitted from and Accumulated in Tea Leaves

C₆-Aldehydes emitted from intact tea leaves were analyzed quantitatively.Emission of the aldehydes increased temporarily in mid-May whenenzymatic activities involved in aldehyde formation from lipidsbegan to increase. Levels of C₆-aldehydes in tea leaves alsoincreased temporarily. However, the accumulated C₆-aldehydesdid not always correspond to emitted ones. (Received December 1, 1991; Accepted March 18, 1992)     

Ca2+ is Required by Clubroot Resistant Turnip Cells for Transient Increases in PAL Activity that Follow Inoculation with Plasmodiophora brassicae

Phenylalanine ammonia‐lyase (PAL, EC 4.3.1.5) activity in clubroot disease‐resistant turnip calli was transiently increased by 20 h after the inoculation with Plasmodiophora brassicae spores. The magnitude of the increase in PAL activity was four to six times higher than constitutive PAL activity. There was no transient increase in PAL activity in susceptible calli. Preincubation of calli in Ca²⁺‐free medium or the removal of Ca²⁺ from cell surfaces by ethylene glycol bis(2‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid‐chelation, completely inhibited induced PAL activity. The influx of exogenous Ca²⁺ into cells appears necessary for this pathogen induced PAL activity. Verapamil and the calmodulin inhibitor W7 almost completely inhibited induced PAL activity at 1 and 0.1 mm , respectively. Neomycin, ruthenium red and (1‐(6‐[(17β‐3‐Methoxyestra‐1,3,5‐(10)‐trien‐17‐yl)amino]hexyl)‐1H‐pyrrole‐2,5‐dione) did not inhibit induced PAL activity. Thus, verapamil and N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulphonamide hydrochloride‐sensitive Ca²⁺‐mediated signalling process appear necessary for P. brassicae induced PAL activity. As the protein synthesis inhibitor cycloheximide (CHX) blocked the induced increasing PAL activity, de novo synthesis of PAL appears to be required for turnip cell defence reactions against P. brassicae.