Induction of cyclooxygenase-2 is responsible for interleukin-1 beta-dependent prostaglandin E2 synthesis by human lung fibroblasts

Because interleukin-1 beta (IL-1 beta) increases the synthesis of prostaglandin E2 (PGE2) in human lung fibroblasts, the effect of IL-1 beta on the expression of two isozymes of cyclooxygenase (cyclooxygenase-1 and -2) in human embryonic lung fibroblasts (IMR-90) was investigated in terms of three parameters (PGE2 release, cyclooxygenase activity, and mRNA). When the cells were incubated with IL-1 beta, both the PGE2 release to the culture medium and the cyclooxygenase activity in the cell lysate increased in a dose- and time-dependent manner, and both were inhibited by NS-398 (a cyclooxygenase-2-specific inhibitor). Dexamethasone and interleukin-4 (IL-4) inhibited the IL-1 beta-induced PGE2 synthesis; the former inhibited the IL-1 beta-induced cyclooxygenase activity whereas the latter failed. As analyzed by Northern blot, cyclooxygenase-1 mRNAs (3.0 Kb and 5.0 Kb) were detected with resting cells and did not increase by the addition of IL-1 beta. In contrast, the cyclooxygenase-2 mRNA (4.4 Kb) was undetectable with resting cells, but was increased dramatically up to 4 to 8 h by the addition of IL-1 beta. Dexamethasone inhibited the IL-1 beta-induced mRNA expression of cyclooxygenase-2 whereas IL-4 failed. These results indicate that IL-1 beta induces cyclooxygenase-2 rather than cyclooxygenase-1 in IMR-90 cells and this induction is responsible for the augmentation of PGE2 production stimulated with IL-1 beta. However, the inhibition of the IL-1 beta-induced PGE2 synthesis by IL-4 was not mediated by the down-regulation of cyclooxygenase-2.

Inositol 1,4,5-trisphosphate 3-kinase activity in FRTL-5 cells: regulation of the enzyme activity by TSH

Inositol 1,4,5-trisphosphate (InsP3) 3-kinase phosphorylates the Ca(2+)-mobilizing second messenger InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). InsP3 5-phosphatase dephosphorylates InsP3 to inositol 1,4-bisphosphate (InsP2). We compared the effects of TSH added to a culture of FRTL-5 thyroid cells on the activity of InsP3 5-phosphatase and InsP3 3-kinase. InsP3 3-kinase activity was decreased at a physiological concentration of TSH. Inhibition of this activity started after 3 h of incubation with TSH and was maximal after 24 h. In contrast, InsP3 5-phosphatase activity was not affected by TSH under the same conditions. The inhibitory effect of TSH on InsP3 3-kinase was characterized as follows: a) inhibition of activity was mimicked by both dibutyryl cyclic AMP and forskolin; b) activity obtained by mixing lysates of TSH-stimulated and non-stimulated cells was the sum of each activity measured separately; c) inhibition persisted after a crude lysate of TSH-stimulated cells had been subjected to SDS/polyacrylamide gel electrophoresis and the extraction of InsP3 3-kinase activity. The data suggest that TSH reduced the activity of InsP3 3-kinase in FRTL-5 cells either by a phosphorylation/dephosphorylation mechanism, or by affecting expression of the enzyme.

A variant form of cyclin-dependent kinase 2 (Cdk2) in a malignantly transformed rat thyroid (FRTL-Tc) cell line

Cyclin-dependent kinase 2 (Cdk2) controls the transition from the G1 to the S phase in the mammalian cell cycle. We found by immunoblotting that anti-Cdk2 antibodies recognize three Cdk2 proteins (of 33, 34 and 39 kDa) in FRTL-5 and FRTL-Tc cells (malignantly transformed FRTL cells). Although 33 kDa protein is a phosphorylated form of 34 kDa protein previously reported, the nature of 39 kDa protein is unknown. In order to determine the nature of this protein, we screened a FRTL-5 cDNA library. Two cDNA clones of the rat homologue (rat Cdk2-alpha and -beta) of human Cdk2 were isolated. The open reading frame of rat Cdk2-alpha cDNA encoded a protein with 428 amino acids and has a high degree of conservation with human Cdk2. The calculated molecular weight of Cdk2-alpha protein is 33892 Da. The rat Cdk2-beta cDNA was identical to Cdk2-alpha cDNA except that it had extra 144 bp; this coincided with insertion of 48 amino acids into Cdk2-alpha protein between Met 196 and Val 197. The calculated molecular weight of Cdk2-beta protein is 39087 Da. Northern blot analysis indicated that the sizes of rat Cdk2-alpha and -beta mRNAs are approximately 2.5 kb and 3.0 kb, respectively. Partial proteolytic mapping showed that Cdk2-beta gene product is 39 kDa Cdk2 in the immunoblotting. We also found that Cdk2-beta protein binds to cyclin A and suc1 proteins. During G1-S phase in FRTL-Tc cells, Cdk2-alpha protein level is constant, but is gradually phosphorylated. In contrast, the level of Cdk2-beta protein increases through the S phase and decreases at the early G2 phase. These results suggest that a variant form of Cdk2 protein might be required for entry into the S phase of the cell cycle in FRTL-Tc cells.

Mitochondrial presequences can induce aggregation of unfolded proteins

We have studied the interactions between various synthetic peptides and two model unfolded proteins, reduced alpha-lactalbumin and reduced and carboxymethylated alpha-lactalbumin. We found that mitochondrial presequences could induce aggregation of the unfolded alpha-lactalbumins but not of the native alpha-lactalbumin. The presequence-induced aggregation of unfolded alpha-lactalbumin was dependent on electrostatic interactions and on the amphiphilicity of the presequences. Since positive charge and amphiphilicity are necessary for the targeting function of mitochondrial presequences, presequence-induced aggregation may be responsible for the instability of mitochondrial precursor proteins and may need to be inhibited by binding factors in the cytosol.

Diagnostic usefulness of chest computed radiography--film versus cathode-ray tube images

Seventy-one plain chest images obtained by computed radiography (CR) with an imaging plate were interpreted on film and two kinds of cathode-ray tube (CRT) monitors installed separately at two facilities (1,024 x 1,536 pixels, 8 bits, and 1,024 x 1,280 pixels, 10 bits) by 20 radiologists and four chest internists. The clinical categories of these 71 cases included pulmonary nodules and interstitial abnormalities. Image reading sessions were held over a total of 4 days, ie, 2 days and then another 2 days, 3 weeks later. Twenty-four observers formed four groups with six members each. Two groups read either films or CRT images at one of the two facilities. In the second experiment, 26 of 71 images were compressed at 10:1, 19 of 71 were compressed at 20:1, and 26 were not compressed. Analyses of the areas under the receiver-operating characteristic curves showed no significant differences in detection of pulmonary abnormalities between film and CRT. In detecting interstitial pulmonary abnormalities, film was more sensitive than CRT monitor. There were no significant differences in observers' performances between the two different kinds of CRT workstation. Subjective evaluation of image quality showed that images irreversibly compressed to the ratios of 10:1 and 20:1 were inferior to original images. Although further considerations are needed with regard to spatial resolution requirements, image processing, and image compression, the utilization of CR CRT image as a substitute for CR film image will be possible.

Pharyngoesophageal reconstruction with a tensor fasciae latae free flap

This report describes our experience with the use of a tensor fasciae latae flap in total reconstructions of the hypopharynx and cervical esophagus. This flap is durable, reliable, and easy to elevate. Moreover, it is possible to obtain a tight two-layer closure of the circumferential suture lines by means of the vascularized fascia. We think this flap will be one of the methods of choice in reconstructions of the hypopharynx and cervical esophagus.

Inactivation of blasticidin S by Bacillus cereus. V. Purification and characterization of blasticidin S-deaminase mediated by a plasmid from blasticidin S resistant Bacillus cereus K55-S1

Blasticidin S (BS) deaminase (BSR) from a BS-resistant strain, Bacillus cereus K55-S1, was purified to homogeneity. Molecular weights determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by gel filtration on HPLC are about 15500 and 35000, respectively, indicating the enzyme is a homodimer. The amino acid composition and N-terminal sequence of BSR are the same as those deduced from the nucleotide sequence of the BS-resistant gene, bsr. The optimum temperature and pH for enzyme activity are 60-65 degrees C and near 10.0, respectively. The activity of BSR is inhibited by Cu2+, Hg2+, and p-chloromercuric benzoate (PCMB). Inhibition by PCMB or HgCl2 is reversible by the addition of SH reagents. The enzyme catalyzes the deamination of BS and its derivatives, but not cytosine nucleosides.

Metal transport in cells: cadmium uptake by rat hepatocytes and renal cortical epithelial cells

The toxic metals appear to use the transport pathways that exist for biologically essential metals. In this regard interactions between the toxic and essential metals are possible. This report summarizes recent findings on the transport of cadmium in rat hepatocytes and renal cortical epithelial cells in the presence or absence of certain essential metals. The transport of cadmium in hepatocytes does not require energy and, therefore, is not an active process. It occurs primarily (80%) by temperature-sensitive processes, i.e., ion channels and carriers, that involve interaction with sulfhydryl groups. These processes apparently exist for the transport of essential metals like copper, zinc and calcium. The remaining 20% of the cadmium in hepatocytes is transported via a temperature-insensitive process, possibly by diffusion. In comparison with the hepatocytes, a smaller fraction (30%) of the cadmium transport through the basolateral membrane and none from the apical membrane of the renal cortical epithelial cells is temperature-sensitive. Total accumulation through the basolateral membrane is about twice that through the apical membrane. A majority of the cadmium transport in the renal cells is by diffusion. As in hepatocytes, copper, zinc and mercury antagonize cadmium transport through the apical membranes of the renal cells. The relative antagonism by copper is the same (25%); however, the antagonism by zinc (16%) and mercury (10%) is 4- to 6-fold lower than in hepatocytes. It appears that the relative contribution of various transport pathways available for cadmium uptake is different in each cell type and apparently depends on the morphological and functional differences between the cell membranes.

Differential effects of bright light and social cues on reentrainment of human circadian rhythms

Reentrainment of human circadian rhythm to an 8-h advanced schedule of sleep and social contacts was assessed under two different conditions: with and without bright light (4,000-6,000 lx). Subjects spent 15 days without knowing the natural day-night alternation. On the fourth day, the social schedule was phase-advanced by 8 h. In one experiment, a bright light pulse of 3-h duration was given in every subjective morning, and in the other no light pulse was applied. Plasma melatonin and rectal temperature rhythms were measured. Seven of nine subjects showed an orthodromic phase shift, the rate of which was significantly larger with bright light pulses than without them. The maximum phase-advance shift by three consecutive light pulses was observed when the first pulse was applied approximately 4 h after the onset of melatonin rise. By contrast, the maximum phase shift of a similar extent was detected at 1 h after the onset of melatonin rise, when ordinary room light (300-500 lx) at the time corresponding to bright light was regarded as a dim light pulse. It is concluded that bright light accelerates the reentrainment of human circadian rhythm, and bright light and social schedule have differential effects on the reentrainment.

Identification of yeast MAS17 encoding the functional counterpart of the mitochondrial receptor complex protein MOM22 of Neurospora crassa

MOM22 of Neurospora crassa was suggested to be required for the transfer of mitochondrial precursor proteins from the receptors to the protein translocation machinery. We isolated a yeast mutant the viability of which depended on the expression of the introduced N. crassa MOM22 gene. The mutant cells showed defects in protein import into mitochondria when the cells were depleted of MOM22. By screening for suppressor genes for the mutant, we could identify the yeast gene MAS17 encoding the functional counterpart of MOM22. The MAS17 gene was found to be essential for the viability of yeast cells.

A novel approach to mode of action of cationic biocides: morphological effect on antibacterial activity

A new concept for the mode of action of cationic biocides is proposed in which the antibacterial activity of cationic disinfectants is ascribed essentially to molecular organizations of cations within aggregates, i.e. the activity is determined by the size of aggregates and number of active molecules comprising the aggregate. On the basis of the new concept, the morphological effect of disinfectants in aqueous solution on the antibacterial activity is discussed for low molecular weight phosphonium salts with single and double long alkyl chains (carbon number 14). The proposed new concept can be applied to all phenomena reported previously in antibacterial activity of cationic biocides and this concept is very important from the viewpoint of molecular design of more active cationic biocides.

Keloid formation after surgery for release of polysyndactyly of the feet in a child

Keloid formation on the hands and the feet is very rare but should always be anticipated as a possible complication after surgery. Failure to recognise the potential for keloid may result in a severe deformity that is functionally and cosmetically undesirable. We report severe keloid formation after simple release of polysyndactyly of the feet of a 2-year-old child.

Acanthamoeba sp. from the Philippines: electron microscopy studies on naturally occurring bacterial symbionts

The isolation of two plasmid-like circular DNAs, measuring 52 and 42 kbp, from an Acanthamoeba sp. from the Philippines has led to the demonstration of a bacterial endosymbiont occurring in this free-living amoeba. The 52-kbp band hybridized with a short sequence of cytochrome b gene and was identified as the mitochondrial DNA, whereas the 42-kbp band was identified as plasmid DNA of the bacterial symbionts on the basis of electron microscopy. The endosymbionts are gram-negative, rod-shaped bacteria measuring approximately 1.3 x 0.43 microns and numbering about eight to ten cells per section. They are randomly distributed in both cysts and trophozoites and are surrounded neither by a phagolysosomal membrane nor by a clear or electron-translucent region. The endosymbiont membrane appears to have a close association with ribosomes, which are seen to be more concentrated within the vicinity of the symbionts than elsewhere within the cytoplasm. Attempts to grow the symbionts and the amoebae separately have failed.

[Principal component analysis of body surface potential distribution and that clinical application]

The purpose of this study was to compress a huge amount of body surface potential data with principal component analysis. The first 6 principal components were extracted from data set obtained from both 25 normal subjects and 100 patients. The factor loading from the 1st to the 3rd principal component (PC) displayed dipolar distribution and that from the 4th to the 6th PC displayed multipolar distribution. In conclusion, the principal component analysis on body surface maps successfully condensed mapped data without significant loss of total variance and it was suggested that this method may be useful for detecting the presence of multipolar distribution.

[Detection of wall motion abnormality in old myocardial infarction with principal component analysis to body surface potential distribution]

The purpose of this study was to examine the correlation between body surface potential distribution and the extent of abnormally contracting segments (ACS) of the left ventricle in patients with old myocardial infarction (MI). Body surface potential distribution was quantitatively analyzed using principal component analysis. The first 6 principal components were extracted from data set obtained from both 25 normal subjects and 100 patients. The z scores were calculated at every 4 or 8 msec in another 81 patients with previous MI. In conclusion, the principal component analysis on body surface maps successfully condensed mapped data without significant loss of total variance and minute differences in the extent of ACS were sensitively detected on z scores of principal components.

Identification of the SecA protein homolog in pea chloroplasts and its possible involvement in thylakoidal protein transport

Recently, we identified the SecA and SecY proteins in the cyanobacterium Synechococcus PCC7942. Antibodies raised against cyanobacterial SecA specifically reacted with a 110-kDa protein of pea chloroplasts, suggesting the presence of SecA in higher plant chloroplasts. A part of the pea secA cDNA was polymerase chain reaction-amplified with degenerated oligonucleotide primers and with pea cDNA as a template. The deduced amino acid sequence shows 62% identity with cyanobacterial SecA and 52% identity with Escherichia coli SecA. Antibodies raised against the pea SecA fragment, which was expressed in E. coli cells from the obtained polymerase chain reaction-amplified cDNA, reacted with the 110-kDa chloroplast protein; the 110-kDa protein was mainly found in the stroma but partly in the thylakoid membrane. The anti-pea SecA IgG inhibited the in vitro import of the 33-kDa protein of the oxygen-evolving complex, but not of the 23-kDa protein of the oxygen-evolving complex, into thylakoids. These results suggest that SecA facilitates transport of a subset of thylakoid lumenal proteins including the 33-kDa protein into thylakoids. We propose that a bacterial-type Sec protein-dependent transport system operates for protein transport into thylakoids in higher plant chloroplasts.

Effects of anti-progesterone compound RU486 on ovulation in immature mice treated with PMSG/hCG

The effects of RU486, a competitive antagonist of progesterone, on ovulation were studied in PMSG/hCG-treated immature mice. PMSG/hCG was administered to 3-week-old female mice to induce ovulation. A dose of 0.5 mg of RU486 was administered 3 h before hCG injection, simultaneously with hCG injection, or 3, 4.5, 6, 7.5 or 9 h after hCG administration. The lowest number of ovulated eggs was observed in the group given RU486 6 h after hCG injection. Although the mean number of ovulated eggs was only 4.4 in this group, it was increased to 25.7 by supplementary administration of 2.0 mg of progesterone. It was demonstrated that RU486 had inhibitory effects on ovulation, and the inhibition could be prevented by supplementary administration of progesterone.

Desensitization and internalization of a thyrotrophin receptor lacking the cytoplasmic carboxy-terminal region

To understand the functional significance of the carboxy-terminal half of the intracellular region of the human TSH receptor (hTSHR), a mutant hTSHR lacking amino acids from the carboxy-terminal to His726 was constructed. Wild type hTSHR cDNA and truncated hTSHR cDNA were subcloned into a eukaryotic expression vector, pRc/CMV, and transfected into Chinese hamster ovary cells to obtain cell lines which stably expressed hTSHRs at high levels. This allowed us to observe highly efficient coupling of hTSHR and adenylyl cyclase as well as desensitization and internalization of hTSHR. Despite the differences in potential phosphorylation sites and internalization signals, dose-dependent stimulation of adenylyl cyclase by TSH, TSH-dependent desensitization and the rate of hTSHR internalization were similar for wild type and truncated hTSHRs. We conclude that the carboxy-terminal half of the intracellular region of hTSHR does not have a major functional role in TSH-dependent signal transduction.