A tRNA-like structure is present in 10Sa RNA, a small stable RNA from Escherichia coli

We have determined that 10Sa RNA (one of the small stable RNAs found in Escherichia coli) has an interesting structural feature: the 5' end and the 3' end of 10Sa RNA can be arranged in a structure that is equivalent to a half-molecule (acceptor stem and TFC stem-loop) of alanine tRNA of E. coli. Primer-extension analysis of 10Sa RNA extracted from a bacterial mutant with temperature-sensitive RNase P function revealed that the precursor to 10Sa RNA (pre-10Sa RNA) is folded into a pre-tRNA-like structure in vivo such that it can be cleaved by RNase P to generate the 5' end of the mature 10Sa RNA. The purified 10Sa RNA can be charged with alanine in vitro. Disruption of the gene encoding 10Sa RNA (ssrA) caused a reduction in the rate of cell growth, which was especially apparent at 45 degrees C, and a reduction in motility on semisolid agar. These phenotypic characteristics of the deletion strain (delta ssrA) allowed us to investigate the effects of some mutations in 10Sa RNA in vivo, although the exact function of 10Sa RNA still remains unclear. When the G.U pair (G3.U357) in 10Sa RNA, which may be equivalent to the determinant G.U pair of alanine tRNA, was changed to a G.A or G.C pair, the ability to complement the phenotypic mutations of the delta ssrA strain was lost. Furthermore, this inability to complement the mutant phenotypes that was caused by the substitution of the determinant bases by a G.A pair could be overcome by the introduction of a gene encoding alanyl-tRNA synthetase (alaS) on a multicopy plasmid. The evidence suggests that the proposed structural features of 10Sa RNA are indeed manifested in vivo.

Primary and higher order structures of nematode (Ascaris suum) mitochondrial tRNAs lacking either the T or D stem

By fractionation using polyacrylamide gel electrophoresis and/or a preparative hybrid selection method employing solid-phase DNA probes, we prepared and characterized mitochondrial tRNAs from the body wall muscle of Ascaris suum, all of which are thought to lack either the T stem or the D stem from their gene sequences (Okimoto, R., and Wolstenholme, D. R. (1990) EMBO J. 10, 3405-3411). Some of the partially purified tRNAs were appreciably aminoacylated with an extract of A. suum mitochondria. The three species sequenced had CCA sequence at their 3'-ends, and tRNA(Met) had 5-formylcytidine at the anticodon first position, a new modified nucleoside found at the same position of bovine mitochondrial tRNA(Met) (Moriya, J., Yokogawa, T., Wakita, K., Ueda, T., Nishikawa, K., Crain, P. F., Hashizume, T., Pomerantz, S. C., McCloskey, J. A., Kawai, G., Hayashi, N., Yokoyama, S., and Watanabe, K. (1994) Biochemistry 33, 2234-2239). Enzymatic probing of these tRNAs supported the secondary structural model proposed by Okimoto and Wolstenholme in the reference cited above. Chemical probing of tRNA(Phe) demonstrated the existence of tertiary interactions between the (T arm-variable loop)-replacement loop and the D arm. The results suggest that these tertiary interactions enable the bizarre tRNAs of nematode mitochondria to maintain an L-shape-like structure in order to function in the nematode mitochondrial translation system.

[Nonpeptide angiotensin II-receptor antagonists]

The renin-angiotensin system (RAS) is known to play a very important role in cardiovascular diseases. The present state of the research on orally active nonpeptide angiotensin II (A II)-receptor antagonists and their pharmacological characterization will be reviewed. In the late 1970s, the first nonpeptide A II-receptor antagonists were discovered among some derivatives of imidazoleacetic acid, and this was followed by the development of losartan in 1989. TCV-116, synthesized in our laboratories, is a prodrug that is converted in vivo to the active form CV-11974. TCV-116 and CV-11974 were demonstrated to be effective antagonists for many A II-induced cardiovascular actions and are effective antihypertensive agents in several animal models of hypertension. TCV-116 also demonstrated secondary benefits in treating congestive heart failure (CHF), preventing stroke, delaying the progression of renal disease and preventing the intimal thickening of vascular injury in animal models. Clinical studies confirmed the efficacy of TCV-116 in the treatment of essential hypertension. The utility of A II antagonist may extend beyond that of hypertension and CHF, as suggested by the potential usefulness of ACE inhibitors in the treatment or prevention of many other cardiovascular diseases. The A II antagonists will help to determine the role of the RAS in the physiologic regulation and in the pathophysiology of various cardiovascular diseases.

Structural model of the ATP-binding domain of the F1-beta subunit based on analogy to the RecA protein

In contrast to the previous topological model of the ATP binding domain of the F1-ATPase beta subunit based on analogies to those of ras p21 and adenylate kinase, a more consistent model can be constructed with the known structure of the recA protein as a reference. The secondary structure of the F1-ATPase beta subunit predicted from the primary structure agrees well with that of the recA protein. The topology includes a repetitive beta alpha c beta alpha beta alpha beta alpha beta structure where all beta strands are parallel and surround the central alpha c helix above which bound ATP is located. Several residues thought to be located at catalytic site as reported in genetic and chemical labeling work can be consistently positioned in this model.

Sequencing and characterization of the kinesin-related genes katB and katC of Arabidopsis thaliana

Complementary DNAs of two kinesin-related genes, katB and katC, were isolated from Arabidopsis thaliana and sequenced. The carboxyl-terminal regions of the polypeptides encoded by these genes, especially the presumptive ATP-binding and microtubule-binding domains, share significant sequence homology with the mechanochemical motor domain of the kinesin heavy chain. The predicted secondary structures of KatB and KatC proteins include a large globular domain in the carboxyl-terminal region and a small globular domain in the amino-terminal region that are separated by a long alpha-helical coiled-coil with heptad repeats. A truncated KatC polypeptide (KatC(207-754)), which includes the carboxyl-terminal region of KatC, was expressed in Escherichia coli and was shown to possess microtubule-stimulated ATPase activity and to bind to microtubules in an ATP-sensitive manner, both of which are characteristics of kinesin and kinesin-like proteins.

Assessment of testicular biopsy after cessation of maintenance chemotherapy in childhood acute lymphoblastic leukemia: a report from the Children's Cancer and Leukemia Study Group

Among 484 male patients with acute lymphoblastic leukemia (ALL) registered into the protocols CCLSG 811, 841 and 874, from 1981 through 1990, 246 patients completed their protocols and were in continuous complete remission (CCR) for more than 3 years. One hundred and seven patients received bilateral testicular biopsies at the time of cessation of maintenance chemotherapy. Eight patients (7.5%) were found to have occult testicular leukemia (TL). Three of them did not receive any additional therapy and all suffered subsequent relapses; one bone marrow relapse and two testicular relapses. The other 3 patients received testicular radiation combined with an additional 2 years of chemotherapy, resulting in CCR for more than 6 years 10 months, 7 years 6 months, and 8 years 6 months. One with chemotherapy alone and another with radiation alone showed subsequent relapse. Overt TL after negative initial biopsy was developed in 3 (3.0%) of the 99 patients. All of them received testicular radiation with chemotherapy, resulting again in CCR for more than 1 year 0 months and 5 years 3 months; one patient showed relapse in testes and bone marrow after 3 years 8 months of CCR. These studies suggested that occult TL has an adverse prognostic significance unless retrieval chemotherapy is given and that performance of testicular biopsy at completion of maintenance chemotherapy is not contributory to prolongation of disease-free survival for males with ALL because the treatment employing testicular radiation plus retrieval chemotherapy for both occult TL and isolated overt TL after off-therapy is similarly very effective.

Basic fibroblast growth factor and steroid receptors in the aging hippocampus of the brown Norway rat: immunocytochemical analysis in combination with stereology

The effect of aging on the hippocampal formation of the male Brown Norway rat was studied by immunohistochemistry and measurements of the immunoreactive hippocampal cells using stereological techniques. The total estimated number of glucocorticoid receptor (GR) immunoreactive neurons of the CA1-CA2 area did not differ in the 3- and the 36-month-old rat. However, the intensity of the GR immunoreactivity was decreased in the aged animals. A gradual decrease of the immunoreactivity for the mineralocorticoid receptor was also observed in the CA1-CA2 area. In the stratum oriens and the stratum radiatum of the CA1-CA2 area the immunoreactivity for basic fibroblast growth factor (bFGF) present in the glia was found to be reduced [20,000 +/- 2100 (n = 6)] in the 36-month-old rat vs the 3-month-old rat [28,500 +/- 4500 (n = 4) (*P = 0.05)]. However, there was no difference in the number of glial fibrillary acidic protein immunoreactive cells of this area in these two age groups. The present findings give evidence that in the Brown Norway rat there is no loss of the neuronal population containing glucocorticoid receptors of the CA1-CA2 area during aging but suggest that aging is characterized by deficits of glially derived growth factors, such as bFGF.

KP-10, a novel protein kinase C substrate in intact mouse epidermal cells, is phosphorylated by novel protein kinase C eta and/or zeta

Recently this group found an endogenous substrate protein for Ca(2+)-independent novel protein kinase C (nPKC), i.e. KP-10 (pI 4.7/25,500 M(r)), in primary cultured mouse epidermal cells [Nishikawa, K. et al. (1992) Cell. Signal. 4, 757-776]. In the present study, the nPKC isozymes which phosphorylate KP-10 in these cells were determined. Western blot analysis revealed that PKC alpha, eta and zeta were present in epidermal cell 105,000 g supernatants and that the content of PKC zeta was much higher than those of PKC alpha and eta. Neither PKC beta, delta nor epsilon was detected in the 105,000 g supernatants. Phosphatidylserine and phorbol 12-myristate 13-acetate (PMA)-dependent KP-10 phosphorylating activity was immunoprecipitated by anti-PKC eta and zeta antibodies, but not by antiPKC alpha antibody. These results suggest that PKC eta and/or zeta phosphorylate KP-10 and play pivotal roles in intracellular signal pathways in intact epidermal cells.

[Quantitative flow-cytometric analysis of CD34-positive stem cells in peripheral blood stem cell harvests]

The percentage of CD34-positive cells (the CD34-positive rate) in peripheral blood stem cell harvests (PBSCH) was determined using two color flow cytometric methods, i.e., representation in a histogram (the histogram method) and the two-dimensional side scatter-fluorescence representation (the SSC-FL method). For all samples examined, the CD34-positive rate obtained using the histogram method was higher than that obtained using the SSC-FL method. This finding was probably due to the fact that some monocytes non-specifically reacted with anti-CD34 monoclonal antibody, and the histogram method could not distinguish these non-specifically stained cells from CD34-positive precursor cells. On the other hand, the SSC-FL method seemed to yield a more accurate measurement of the percentage of CD34-positive cells in PBSCH samples. Based on this finding, it is recommended that the histogram method, which is currently used at most commercial laboratories, be reviewed in favor of the SSC-FL method when the CD34-positive cell rate of PBSCH is to be determined.

A study of CD45RO, CD45RA and CD29 antigen expression on human decidual T cells in an early stage of pregnancy

The decidua is the place where the fertilized egg is implanted and where the immunocompetent cells of the mother come into direct contact with genetically disparate cells of the conceptus. Although the T cells in the decidua are exposed to fetal antigens, the fetus is not rejected by maternal immunocompetent cells. In the present study, we examined surface markers to determine whether the T cells in the human decidua are naive T cells without or memory T cells with a history of antigen stimulation. Although few T cells were present in the decidua, as compared to the peripheral blood, CD45RO+, CD29+ and CD45RA- CD4+ T cells as well as CD45RO+, CD29+ and CD45RA- CD8+ T cells, which are considered to be memory T cells, were in the majority, with only small numbers of CD45RO-, CD29- and CD45RA+ CD4+ and CD8+ cells, which are naive T cells, present. Also, the decidual mononuclear cells secreted IL-2 and IL-4. Since IL-4 is secreted only by memory T cells, it is suggested that in the decidua memory T cells increase in number and secrete cytokines, thereby in some way influencing the phenomenon of fertility.

Effect of CTLA-4 chimeric protein on rat autoimmune anti-glomerular basement membrane glomerulonephritis

The interaction of the T cell receptor with the antigen/major histocompatibility class II complex is insufficient to induce optimal T cell activation. Co-stimulatory signals, including those provided by CD28/CTLA-4 on T cells and B7 molecules (B7-1, -2, and -3) on antigen-presenting cells, are also required. CD28-B7 interactions can be blocked by a soluble human CTLA-4 chimeric protein (CTLA4Ig). We tested the effect of administration of CTLA4Ig on experimental anti-glomerular basement membrane (GBM) autoimmune glomerulonephritis in Wistar-Kyoto rats induced by immunization with bovine GBM. The disease is characterized by development of antibody to the alpha 3 chain of type IV collagen (Goodpasture's antigen), deposition of rat IgG in GBM, infiltration of the kidney by T cells and macrophages, severe crescent formation and renal failure leading to death in 5-6 weeks. Animals injected with human CTLA4Ig from day 0 to day 14 or to day 35 had reduced disease severity. Beneficial effects were observed even when injections were begun after the onset of glomerulonephritis on day 14. However, the rats developed antibody to the human CTLA4Ig, associated with reduction in levels of circulating CTLA4Ig. The results provide evidence for CD28/CTLA-4 signaling in rat autoimmune glomerulonephritis, and suggest that more effective inhibition of B7-dependent T cell activation, such as might be achieved with homologous CTLA4Ig, could be useful in the treatment of autoimmune diseases.

Bullous eruption of systemic lupus erythematosus

A bullous eruption is now recognized as a specific complication of systemic lupus erythematosus (SLE). We described a 22-year-old woman with SLE whose vesiculobullous eruptions exacerbated with a flare of visceral manifestations of the disease and resolved when the systemic disease was controlled by oral prednisolone.

Relationship among coelacanths, lungfishes, and tetrapods: a phylogenetic analysis based on mitochondrial cytochrome oxidase I gene sequences

To clarify the relationship among coelacanths, lungfishes, and tetrapods, the amino acid sequences deduced from the nucleotide sequences of mitochondrial cytochrome oxidase subunit I (COI) genes were compared. The phylogenetic tree of these animals, including the coelacanth Latimeria chalumnae and the lungfish Lepidosiren paradoxa, was inferred by several methods. These analyses consistently indicate a coelacanth/lungfish clade, to which little attention has been paid by previous authors with the exception of some morphologists. Overall evidence of other mitochondrial genes reported previously and the results of this study equally support the coelacanth/lungfish and lungfish/tetrapod clades, ruling out the coelacanth/tetrapod clade.

Substrate specificity of tRNA (adenine-1-)-methyltransferase from Thermus thermophilus HB27

tRNA (adenine-1-)-methyltransferase was purified to homogeneity from an extreme thermophile, Thermus thermophilus HB27, by several steps of column chromatographies. The molecular weight of this enzyme was about 60,000 as analyzed by SDS polyacrylamide gel electrophoresis. Km for E. coli tRNA(2Glu) was 100 nM and that for the methyl group donor, S-adenosyl-L-methionine, was 7.8 microM. The substrate specificity of the enzyme was investigated by using T7 RNA polymerase transcripts and tRNA fragments obtained by partial digestion with RNases. The enzyme was able to transfer the methyl group to the 3'-half fragment of E. coli initiator tRNA, however, the extent of methylation was elevated by more than five times when the 5'-half fragment was added and annealed to the 3'-half. This indicates that the main recognition site of the enzyme is within the 3'-half region of tRNA molecule, while the tertiary interaction between the T-loop and the D-loop is very effective for the adequate methylation reaction.

Prediction of the structural similarity between spermidine/putrescine-binding protein and maltose-binding protein

A structural similarity between spermidine/putrescine-binding protein and maltose-binding protein has been predicted by a sequence-structure compatibility method. The sequence alignment obtained by this method revealed a consensus sequence motif located on the surface loop between the first alpha-helix and the second beta-strand, and the further analysis identified a similar motif in iron-binding protein. The conservation of this motif among certain bacterial periplasmic binding proteins suggests a common functional role for this region as well as an evolutionary relationship between them.

Quantitative assessment of image quality using niobium filtration for cephalometric radiography

The effect of added niobium filtration on image quality in cephalometric radiography was quantitatively evaluated using the Modulation Transfer Function (MTF). A conventional full-wave cephalometric X-ray generator (Quint Sectograph) and a constant potential, high frequency X-ray generator (Orthophos CD) were compared with respect to the effects on the MTF of the added filtration. There was a slight reduction in image quality with both machines when adding niobium filtration.

Effects of unusual polyamines on phenylalanyl-tRNA formation

The effects of novel polyamines on aminoacyl-tRNA formation catalyzed by Escherichia coli., Sulfolobus acidocaldarius, and Thermus thermophilus HB8 S-100 extracts were investigated. These effects were diverse and differed depending on the amino acid and the enzyme used. A quaternary polyamine, tetrakis(3-aminopropyl)ammonium, inhibited phenylalanyl-tRNA synthesis catalyzed by the T. thermophilus extract, but not inhibit the other aminoacyl-tRNA formations tested. The inhibition was observed in hybrid reactions where the thermophile tRNA or extract was replaced by its E. coli counterpart, although the quaternary amine did not inhibit Phe-tRNA formation by the E. coli homologous system. Spermine relieved the inhibition of the reaction of thermophile enzyme and tRNA, but not the inhibition of the hybrid reactions. These results suggest that the branched polyamine interacts with both the thermophile enzyme and tRNA(Phe).

Effects of amiloride derivatives on the thermosensitivity of an adriamycin-resistant strain of Ehrlich ascites tumor cells

We investigated the effects of amiloride and its derivative MH-12-43 on the thermosensitivity of adriamycin-resistant cells. Effects of hyperthermia at 42 degrees C were enhanced by 0.5 mM amiloride and 0.05 mM MH-12-43, which resulted in no decrease in survival rate by the treatment at 37 degrees C for 120 min. Therefore, the combination of hyperthermia and amiloride derivatives was effective in the adriamycin-resistant cells as well as wild type cells. Further, since the survival rates by the treatment with 0.05 mM MH-12-43 were markedly lower than those with 0.5 mM amiloride from hyperthermia at 42 degrees C, MH-12-43 might be more effective than amiloride.

Effects of TCV-309, a novel PAF antagonist, on circulatory shock and hematological abnormality induced by endotoxin in dogs

We investigated the effects of TCV-309, a novel platelet activating factor (PAF) antagonist, on circulatory dysfunction and hematological abnormalities in experimental canine endotoxin (ET) shock. ET caused biphasic hypotension with a decrease in cardiac output (CO), left ventricular systolic pressure (LVP) and its dp/dt(max). The first hypotensive phase occurred within 15 min, and the second phase between 90 and 180 min following the injection of ET. Pulmonary vascular resistance (PVR) abruptly increased at 15 min with a partial recovery, and was then sustained at twice the basal value throughout the experiment. TCV-309 attenuated the hypotension, the decrease in CO, LVP and its dp/dt(max), and the increase in PVR. TCV-309 had no significant effect on the increase in TPR. The decrease in plasma fibrinogen and the increase in hematocrit and plasma lactate were significantly attenuated by TCV-309. These data suggest that PAF may be a key mediator leading to shock in sepsis.

[Transurethral hyperthermic treatment in patients with benign prostatic hypertrophy]

Transurethral hyperthermic treatment was performed on 30 patients with benign prostatic hypertrophy (BPH). Two patients had a urethral catheter because of urinary retention. The prostate was heated transurethrally. The treatment consisted of 3-8 sessions of 60 min. each. To evaluate this treatment, the following parameters were determined before and 1-5 weeks after the last hyperthermia session; subjective symptoms score, and as objective data residual urine volume and uroflowmetry. The symptoms score improved in 25 (83%) patients. Of 2 patients with a catheter, the catheter could be removed from 1 patient. Although there was no change in prostatic volume, significant decreases in residual urine volume, and increases of maximum flow rate and mean flow rate were observed. No adverse reactions were seen. Judging from the above results, this treatment is considered to be useful for patients with BPH.

Efficient expression of E. coli dihydrofolate reductase gene by an in vitro translation system using phosphorothioate mRNA

Dihydrofolate reductase (DHFR) of Escherichia coli (E. coli) was synthesized in a cell-free translation system of E. coli directed by phosphorothioate-containing mRNA (thio-mRNA) which was polymerized by an in vitro transcription of the DHFR gene in the presence of SP diastereomers of ribonucleoside 5'-O-(1-thiotriphosphates). The molecular weights of the products thus obtained were identical to those with the unsubstituted mRNA. Furthermore, the thio-mRNA for DHFR showed higher translational activities than the corresponding unsubstituted mRNA. It is suggested that this effectiveness resulted from the higher stability of thio-mRNA in the cell-free translation system. Amongst the various types of thio-mRNAs, the single substitution of adenosine residues was most effective in translational activity. This higher translational activity of thio-mRNA compared with the unsubstituted mRNA was also demonstrated in a continuous flow cell-free system originally developed by Spirin et al. (1988). Therefore, introduction of sulfur atoms into phosphodiester bonds of mRNA appears to be a useful strategy for the stabilization of mRNA in large-scale protein production in vitro.

Discrimination of intracellular and extracellular proteins using amino acid composition and residue-pair frequencies

Sequences of intracellular and extracellular soluble proteins were analyzed statistically in terms of amino acid composition and residue-pair frequencies. Residue-pair frequencies were calculated for sequential separations from (n, n + 1) to (n, n + 5), and converted into scoring parameters. Then, for each test protein, the single-residue and residue-pair parameters were applied to calculate a total score. According to our definition, a protein which yields a positive score is indicative of an intracellular protein, whereas a negative score implies an extracellular one. The parameter set was derived from 894 sequences constituting different protein families in the PIR database, and assessed by application to a test of 379 proteins. The results showed that 88% of intracellular and 84% of extracellular proteins were correctly assigned. The discrimination power was improved by about 8% in comparison with the previous study, which used composition data alone. Segregation of intra/extracellular proteins is also observed by other criteria, such as structural class (intracellular proteins prefer alpha and alpha/beta types and extracellular proteins prefer beta and alpha + beta types). Segregation by sequence was found to be a more reliable procedure for distinguishing intra/extracellular proteins than methods using structural class. Possible causes for this segregation by sequence are discussed.