Interleukin-12 prevents diaphragm muscle deterioration in a septic animal model

The effects of an intravenous injection of Interleukin-12 (IL-12) after endotoxin administration and without endotoxin administration on diaphragm muscle were studied using Wistar rats. Three treatment groups, namely a control (Saline+endotoxin) group, an IL-12+endotoxin group and an IL-12 only group were studied. E. coli endotoxin (30 mg/kg) was injected intraperitoneally 5 min after Saline or IL-12 (0.25 microg) injection. In the control group, the force-frequency curves, twitch tension (TT) and slope during contraction time (TT/CT) were significantly lower at 4 h than those at 0 h due to endotoxin (P<0.001, P<0.01 and P<0.01, respectively), and NO production was increased at 4 h as shown by NADPH diaphorase staining. In the IL-12+endotoxin group, the decrement of the force-frequency curves, TT and TT/CT induced by endotoxin at 4 h were significantly prevented compared with those of the control group (P<0.001, P<0.05 and P<0.05, respectively), and NO production was blocked at 4 h. In the IL-12 only group, the force-frequency curves were decreased in the range of high frequency and IL-12 resulted in NO production. Furthermore, the positive muscle fibers detected by NADPH diaphorase staining were classified as type I and IIa muscle fibers by ATPase staining in the control and IL-12 only groups. It is concluded that IL-12 prevents the deterioration of diaphragm muscle contraction induced by endotoxin by reducing NO production in type I and IIa muscle fibers. These results suggest that IL-12 and endotoxin may interfere with each other.     

PDMP,a ceramide analogue,acts as an inhibitor of mTORC1 by inducing its translocation from lysosome to endoplasmic reticulum

Mammalian or mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth, metabolism, and cell differentiation. Recent studies have revealed that the recruitment of mTORC1 to lysosomes is essential for its activation. The ceramide analogue 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), a well known glycosphingolipid synthesis inhibitor, also affects the structures and functions of various organelles, including lysosomes and endoplasmic reticulum (ER). We investigated whether PDMP regulates the mTORC1 activity through its effects on organellar behavior. PDMP induced the translocation of mTORC1 from late endosomes/lysosomes, leading to the dissociation of mTORC1 from its activator Rheb in MC3T3-E1 cells. Surprisingly, we found mTORC1 translocation to the ER upon PDMP treatment. This effect of PDMP was independent of its action as the inhibitor, since two stereoisomers of PDMP, with and without the inhibitor activity, showed essentially the same effect. We confirmed that PDMP inhibits the mTORC1 activity based on the decrease in the phosphorylation of ribosomal S6 kinase, a downstream target of mTORC1, and the increase in LC3 puncta, reflecting autophagosome formation. Furthermore, PDMP inhibited the mTORC1-dependent osteoblastic cell proliferation and differentiation of MC3T3-E1 cells. Accordingly, the present results reveal a novel mechanism of PDMP, which inhibits the mTORC1 activity by inducing the translocation of mTOR from lysosomes to the ER.     

An attempt to restore suitable conditions for demersal fishes and crustaceans in the Port of Sakai-Semboku, north Osaka Bay, Japan

Hypoxia and/or anoxia developed in the summer of 1995 and 1996 in the lower water layer in the Port of Sakai-Semboku, north Osaka Bay, causing an increase in sulfide content and a decrease in the redox potential of the bottom sediment. As a result, the number of benthic animal species was reduced and in the innermost part of the port no benthic animals were found. A jet stream pump system was installed at the Dejima Fishing Port, the innermost part of the Port of Sakai-Semboku to improve the oxygen conditions in the bottom waters. This led to an increase in percentage saturation of oxygen (ca. 10% increase) of the lower seawater layer along with an increase in richness and abundance of benthic fishes and crustaceans in the summer. These findings indicate that dissolved oxygen is a crucial environmental factor in the functioning of the port as a habitat for various benthic animals in north Osaka Bay. Based on the results of field surveys, the possibility of restoration of the benthic fauna by using a jet stream pump system is also discussed.     

β3-Adrenoceptor agonists for the treatment of frequent urination and urinary incontinence: 2-[4-(2-{[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino}ethyl)phenoxy]-2-methylpropionic acid

In a search for novel analogues of β₃-adrenoceptor (AR) agonists relaxing the bladder for treatment of urinary dysfunction, 2-[4-(2-{[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino}ethyl)phenoxy]-2-methylpropionic acids (1a–e), into which a fibrate-like structure had been incorporated, were synthesised. Compound 1a was found to be a selective β₃-AR agonist in functional assays using the ferret detrusor (β₃-AR), rat uterus (β₂-AR), and rat atrium (β₁-AR); β₃: EC₅₀=7.8 nM, β₂: IC₅₀=7,300 nM, β₁: EC₂₀=23,000 nM. The introduction of a chlorine atom or methyl substituent at the ortho-position on the phenyl ring of 1a further improved β₃-AR selectivity. In an in vivo study, 1a lowered intrabladder pressure (ED₅₀=31 μg/kg) in rats, without increasing heart rate, in keeping with the in vitro results. Consequently, it is proposed that 1a and its analogues (1b–e), possess β₃-AR agonistic activity in the absence of undesirable β₁- or β₂-AR mediated actions, and may be useful for clinical treatment and pharmacological studies.     

The role of 15-lipoxygenase in disruption of the peroxisomal membrane and in programmed degradation of peroxisomes in normal rat liver.

Our earlier electron microscopic observations revealed that prolonged exposure of glutaraldehyde-fixed rat liver sections to buffer solutions induced focal membrane disruptions of peroxisomes with catalase diffusion as shown cytochemically. Recently, it was suggested that 15-lipoxygenase (15-LOX) might be involved in natural degradation of membrane-bound organelles in reticulocytes by integrating into and permeabilizing the organelle membranes, leading to the release of matrix proteins. We have now investigated the localization of 15-LOX and its role in degradation of peroxisomal membranes in rat liver. Aldehyde-fixed liver slices were incubated in a medium that conserved the 15-LOX activity, consisting of 50 mM HEPES-KOH buffer (pH 7.4), 5 mM mercaptoethanol, 1 mM MgCl(2), 15 mM NaN(3), and 0.2 M sucrose, in presence or absence of 0.5-0.05 mM propyl gallate or esculetin, two inhibitors of 15-LOX. The exposure of aldehyde-fixed liver sections to this medium induced focal disruptions of peroxisome membranes and catalase diffusion around some but not all peroxisomes. This was significantly reduced by both 15-LOX inhibitors, propyl gallate and esculetin, with the latter being more effective. Double immunofluorescent staining for 15-LOX and catalase revealed that 15-LOX was co-localized with catalase in some but not all peroxisomes in rat hepatocytes. By postembedding immunoelectron microscopy, gold labeling was localized on membranes of some peroxisomes. These observations suggest that 15-LOX is involved in degradation of peroxisomal membranes and might have a physiological role in programmed degradation and turnover of peroxisomes in hepatocytes. (J Histochem Cytochem 49:613-621, 2001)     

The morphological and histological characters of the male external genitalia of the house musk shrew, Suncus murinus

External genitalia are the reproductive organs necessary for efficient copulation and internal fertilization in various mammalian species. Their morphogeneses display significant morphological and developmental differences among species. The house musk shrew, Suncus murinus (hereafter described as suncus) is a species of the order Insectivora, which has been considered as primitive and one of the earliest eutheria phylogenetically. Comparative anatomical analyses of phylogenetically different mammals will contribute to the better understanding of morphological diversity of external genitalia. This study performed various anatomical and histological analyses concerning the organization of the external genitalia of male suncus. It was shown that the external genitalia of suncus possessed a muscular structure, which we proposed as musculus ischiocavernosus dorsalis of suncus. The musculus ischiocavernosus dorsalis is originated from the inner surface of the tuber ischiadicum and was allocated adjacent to the corpus cavernosum penis. In addition, a pair of alpha-smooth muscle actin positive muscles was located bilaterally to the urethra. This unique morphology of the external genitalia of suncus males may provide a unique model system to investigate genital morphogenesis.