No abstract available.
Cytosol* ; Muscle, Smooth, Vascular*

Using BHK cells with stable expression of cardiac Na+/Ca2+ exchanger (BHK-NCX1), reverse mode (i.e. Ca2+ influx mode) of NCX1 current was recorded by whole-cell patch clamp. Repeated stimulation of reverse NCX1 produced a cytosolic Ca2+-dependent long-term inactivation of the exchanger activity. The degrees of inactivation correlated with NCX1 densities of the cells and were attenuated by reduced Ca2+ influx via the reverse exchanger. The inactivation of NCX1 was attenuated by (i) inhibition of Ca2+ influx with reduced extracellular Ca2+, (ii) treatment with NCX1 blocker (Ni2+), and (iii) increase of cytoplasmic Ca2+ buffer (EGTA). In BHK-NCX1 cells transiently expressing TRPV1 channels, Ca2+ influx elicited by capsaicin produced a marked inactivation of NCX1. We suggest that cytoplasmic Ca2+ has a dual effect on NCX1 activities, and that allosteric Ca2+ activation of NCX1 can be opposed by the Ca2+-dependent long-term inactivation in intact cells.
Calcium ; Capsaicin ; Cytoplasm ; Cytosol

No abstract available.
Breast Neoplasms* ; Breast* ; Cytosol* ; Humans* ; Receptors, Steroid*

Hypocrellin A has gained much attention in recent years due to its light-induced antitumor, antifungal and antiviral activities. Here we report that hypocrellin A exerts immunomodulatory effects on MHC-restricted presentation of antigen. Hypocrellin A inhibited class II-MHC restricted presentation of exogenous antigen, but not class I MHC-restricted presentation of exogenous antigen, in dendritic cells. Hypocrellin A also inhibited the cytosolic pathway of endogenous antigen presentation. However, hypocrellin A did not inhibit the expression of class I and class II MHC molecules on dendritic cells (DCs), the phagocytic activity of DCs, or the H-2K(b)-restricted presentation of a synthetic peptide, SIINFEKL. These results show that hypocrellin A differentially modulates the MHC-restricted antigen presentation pathways.
Antigen Presentation ; Cytosol ; Dendritic Cells ; Perylene ; Quinones

BACKGROUND: UVB is responsible for most of the carcinogenic effects of sun exposure. OBJECTIVE: Aim of this study was to investigate the regulation and intracellular redistribution of p53 protein after UVB irradiation. METHODS: Cultured normal human melanocytes and G361 melanoma cells were used for west-ern blotting and confocal microscopic examination for determining expression and distribution of p53. RESULTS: UVB irradiation increased p53 expression in cultured normal human melanocytes and G361 malignant melanoma cells according to increasing doses of UVB. Furthermore, p53 moved from cytosol to nucleus after UVB irradiation. CONCLUSIONS: UVB irradiation induced overexpression and redistribution of p53 in cultured normal human melanocytes and G361 malignant melanoma cells.
Cytosol ; Humans ; Melanocytes* ; Melanoma* ; Solar System

No abstract available.
Acne Vulgaris* ; Cytosol* ; Humans ; Propionibacterium acnes* ; Propionibacterium*

BACKGROUND: Reconstructed human epidermal culture skin models have been developed for cosmetic and pharmaceutical research. OBJECTIVE: This study evaluated the total and carboxyl esterase activities (i.e., K(m) and V(max), respectively) and localization in two reconstructed human epidermal culture skin models (LabCyte EPI-MODEL [Japan Tissue Engineering] and EpiDerm [MatTek/Kurabo]). The usefulness of the reconstruction cultured epidermis was also verified by comparison with human and rat epidermis. METHODS: Homogenized epidermal samples were fractioned by centrifugation. p-nitrophenyl acetate and 4-methylumbelliferyl acetate were used as substrates of total esterase and carboxyl esterase, respectively. RESULTS: Total and carboxyl esterase activities were present in the reconstructed human epidermal culture skin models and were localized in the cytosol. Moreover, the activities and localization were the same as those in human and rat epidermis. CONCLUSION: LabCyte EPI-MODEL and EpiDerm are potentially useful for esterase activity prediction in human epidermis.
Animals ; Centrifugation ; Cytosol ; Epidermis ; Humans ; Rats ; Skin*

PURPOSE: Usefulness of mouse liver S9 fraction was evaluated for the measurement of the metabolites in the in vitro metabolism study of 18F-labeled radiotracers. MATERIALS AND METHODS: Mouse liver S9 fraction was isolated at an early step in the course of microsome preparation. The in vitro metabolism studies were carried out by incubating a mixture containing the radiotracer, S9 fraction and NADPH at 37 degrees C, and an aliquot of the mixture was analyzed at the indicated time points by radio-TLC. Metabolic defluorination was further confirmed by the incubation with calcium phosphate, a bone mimic. RESULTS: The radiotracer [18F]1 underwent metabolic defluorination within 15 min, which was consistent with the results of the in vivo method and the in vitro method using microsome. Radiotracer [18F]2 was metabolized to three metabolites including 4-[18F]fluorobenzoic acid within 60 min. It is likely that the one of these metabolites at the origin of radio-TLC was identical with the one that obtained from the in vivo and in vitro (microsome) method. Compared with the in vitro method using microsome, the method using S9 fraction gave a similar pattern of the metabolites but with a different ratio, which can be explained by the presence of cytosol in the S9 fraction. CONCLUSION: These results suggest that the findings of the in vitro metabolism studies using S9 fraction can reflect the in vivo metabolism of novel radiotracers in the liver. Moreover, this method can be used as a tool to determine metabolic defluorination along with calcium phosphate absorption method.
Absorption ; Animals ; Calcium ; Cytosol ; Liver* ; Metabolism* ; Mice* ; Microsomes ; NADP

Carnitine is essential for the transfer of long-chain fatty acids from the cytosol into mitochondria for subsequent beta-oxidation. A lack of carnitine results in impaired energy production from long-chain fatty acids, especially during periods of fasting or stress. Primary carnitine deficiency (PCD) is an autosomal recessive disorder of mitochondrial beta-oxidation resulting from defective carnitine transport and is one of the rare treatable etiologies of metabolic cardiomyopathies. Patients affected with the disease may present with acute metabolic decompensation during infancy or with severe cardiomyopathy in childhood. Early recognition of the disease and treatment with L-carnitine may be life-saving. In this review article, the pathophysiology, clinical presentation, diagnosis, treatment and prognosis of PCD are discussed, with a focus on cardiac involvements.
Cardiomyopathies* ; Carnitine* ; Cytosol ; Diagnosis ; Fasting ; Fatty Acids ; Humans ; Mitochondria ; Prognosis

It has been demonstrated that an unidentified cytosolic factor (s) reduces K (ACh) channel function. Therefore, this study attempted to elucidate the cytosolic factor. Fresh cytosol isolated from normal heart (FC) depressed the K (ACh) channel activity, but cytosol isolated from the ischemic hearts (IC) did not modulate the channel function. Electrophorectic analysis revealed that a protein of ~80 kDa was markedly reduced or even lost in IC. By using peptide sequencing analysis and Western blot, this 80 kDa protein was identified as transferrin (receptor-mediated Fe3+ transporter, 76 kDa). Direct application of transferrin (100 nM) to the cytoplasmic side of inside-out patches decreased the open probability (Po, 12.7+/-6.4%, n=4) without change in mean open time (tau o, 98.5+/-1.3%, n=4). However, the equimolar apotransferrin, which is free of Fe3+, had no effect on the channel activity (N*Po, 129.1+/-13.5%, n=3). Directly applied Fe3+ (100 nM) showed results similar to those of transferrin (N*Po: 21.1+/-3.9%, n=5). However Fe2+ failed to reduce the channel function (N*Po, 106.3+/-26.8%, n=5). Interestingly, trivalent cation La (3+) inhibited N*Po of the channel (6.1+/-3.0%, n=3). Taken together, these results suggest that Fe3+ bound to transferrin can modulate the KACh channel function by its electrical property as a polyvalent cation.
Animals ; Blotting, Western ; Cytoplasm ; Cytosol ; Heart ; Muscle Cells* ; Rats* ; Transferrin*