Breakpoint clusters of the PML gene in acute promyelocytic leukemia: primary structure of the reciprocal products of the PML-RARA gene in a patient with t(15;17)

DNA studies of the translocation t(15;17) in acute promyelocytic leukemia (APL) have shown that the retinoic acid receptor alpha (RARA) gene on chromosome 17 is juxtaposed to the promyelocytic leukemia (PML) gene on chromosome 15. The PML breakpoints have been mapped to 3 clusters: bcr1, bcr2, and bcr3. We have examined the PML breakpoint distribution in a series of 33 Chinese patients with APL. Twenty-two patients fell within bcr1, 2 within bcr2, and 9 within bcr3. The primary structure of the reciprocal chromosome translocation joints of one patient and that of their normal counterparts have been determined and compared to those of 2 previously reported cases. These studies revealed possible topoisomerase II cleavage sites close to the breakpoints and suggested implications of DNA attachment sites to nuclear matrix. We propose that these features are relevant to the process of illegitimate recombination generating the translocation.

Human plasma alpha 2-macroglobulin promotes in vitro oxidative stress cracking of Pellethane 2363-80A: in vivo and in vitro correlations

It is hypothesized in this study that the phenomenon of environmental stress cracking (ESC) in polyetherurethane is caused by a synergistic action of biological components in the body fluids, oxidative agents, and stress. An in vitro system is designed to mimic the in vivo system; human plasma contains certain biological components that can act as a stress cracking promoter, while H2O2 (Co) solution provides an oxidative reaction comparable to that observed in the respiratory burst of adherent macrophages and foreign-body giant cells. It is demonstrated that the phenomenon of in vivo stress cracking in Pellethane 2363-80A is duplicated by an in vitro system that involves a pretreatment of prestressed specimens with human plasma at 37 degrees C for 7 days followed by oxidation in 10% hydrogen peroxide with 0.10M cobalt chloride at 50 degrees C for 10 days. The pretreatment with plasma has a synergistic effect with the oxidation by H2O2 (Co) treatment to produce ESC. A plasma component responsible for promoting stress cracking in Pellethane polyurethane is identified to be alpha 2-macroglobulin (alpha 2M).

Protoplast culture and female plant regeneration in the dioecious plant Melandrium album

Conditions for protoplast isolation and culture in the dioecious species Melandrium album (Silene alba) are described and differences between female and male plants subjected to in vitro culture identified. Plant regeneration was achieved in the case of female plants only. Selection for high regeneration capacity lines was initiated aiming at creating responsive experimental material for further studies. The regeneration behaviour in this dioecious plant is discussed in the context of hormonal models on sex determination.

Sodium lactobionate sucrose solution for canine liver and kidney preservation

With 24-hour preservation of canine liver, SLS solution showed inferior animal survival to UW solution. The lactobionate, raffinose, glutathione, and hydroxyethyl starch in UW solution have been shown to be important for liver preservation. However, our results suggest that sucrose should not be substituted for raffinose for the preservation of livers. In contrast to the liver, SLS solution performed the same or even better than UW solution for kidney preservation. The substitution of sucrose for raffinose, along with the addition of CPZ has either no effect or a slightly positive effect on kidney preservation. In conclusion, SLS solution may be a suitable solution for preserving canine kidneys, but is not suitable for liver preservation. These findings suggest that future development of preservation solutions should be focused on the needs of specific organs and not toward a generic, all encompassing preservation solution.

Element-Specific Magnetic Microscopy with Circularly Polarized X-rays

Circularly polarized soft x-rays have been used with an imaging photoelectron microscope to record images of magnetic domains at a spatial resolution of 1 micrometer. The magnetic contrast, which can be remarkably large, arises from the fact that the x-ray absorption cross section at inner-shell absorption edges of aligned magnetic atoms depends on the relative orientation of the photon spin and the local magnetization direction. The technique is element-specific, and, because of the long mean free paths of the x-rays and secondary electrons, it can record images of buried magnetic layers.

Attenuation properties of lead composite aprons

Traditionally, the absorption properties of protective aprons used in diagnostic radiology have been specified in units of lead equivalent thickness. This is appropriate and accurate when lead is the only high-atomic-numbered component in the apron. In an attempt to manufacture light-weight protective apparel, however, some manufacturers have included other elements with k absorption edges in the energy range of interest, to provide equivalent absorption properties with less weight. With these other high-atomic-numbered elements added, the lead equivalence of the apparel becomes a function of the photon energy. This must be recognized and specified by the supplier, because lead apparel is used in environments other than diagnostic radiology, where the shielding benefits may be substantially less than expected when specifications are based on the diagnostic x-ray energy range.

Temperature sensitivity of aberrant RNA splicing with a mutation in the G+5 position of intron 37 of the gene for type III procollagen from a patient with Ehlers-Danlos syndrome type IV

A single-base mutation in intron 37 of the gene for type III procollagen (COL3A1) was found in a proband with the type IV variant of Ehlers-Danlos syndrome. Probe-protection experiments with S1 nuclease and RNA from fibroblasts incubated at 37 degrees C demonstrated that about 35% of the total mRNA or about 70% of the mRNA from mutated allele was spliced by exon skipping. The effects of the mutation were temperature-sensitive in that the amount of RNA from the mutated allele that was spliced by exon skipping was 87.1 +/- 7.7% at 31 degrees C, 70.1 +/- 6.5% at 37 degrees C, and 85.4 +/- 11.1% at 42 degrees C. The effects of temperature on aberrant RNA splicing were, therefore, the reverse of those reported for four previous mutants in collagen genes. The increase in abnormal RNA splicing when the temperature was raised from 31 degrees to 37 degrees C seen with previously reported mutants suggested that RNA-RNA hybridization of U1snRNA to the 5'-splice site in the substrate may be limiting in the processing of transcripts from the mutated alleles, since RNA-RNA hybridizations become less favorable at higher temperatures. The decrease in abnormal RNA splicing seen here when the temperature was raised from 31 degrees to 37 degrees C suggested that protein-RNA or protein-protein binding steps become rate limiting with the G+5 mutation in intron 37 of the COL3A1 gene.

Increased endogenous N-nitrosamine and nitrate formation by induction of nitric oxide synthase in rats with acute hepatic injury caused by Propionibacterium acnes and lipopolysaccharide administration

In rats treated i.v. with heat-killed Propionibacterium acnes (100 mg/kg body wt), followed 5 days later by an i.v. dose of Escherichia coli lipopolysaccharide (LPS, 1 mg/kg body wt), acute hepatic cell necrosis was accompanied by significant induction of nitric oxide (NO) synthase activity in the liver. Endogenous nitrosation of thiazolidine 4-carboxylic acid (TCA, 50 mumol/rat) administered by three different routes (i.v., i.p. and p.o.) 5 h after LPS injection to the P. acnes-treated rats was assessed by analysing its nitrosated product (NTCA) excreted in 24 h urine. The amounts of NTCA formed in vivo after i.v., i.p. and p.o. administration of TCA were 4.07 +/- 1.00, 5.79 +/- 2.15 and 58.3 +/- 20.7 nmol/rat (n = 5-10) respectively, which were about 5-, 10- and 8-fold greater than those excreted by rats which had not been treated with P.acnes and LPS but received TCA by the same route. Nitrate concentration in plasma and NO synthase activity in the liver started to increase within 2.5 h after LPS injection, reached a maximum at 7.5 h and remained at high levels for several further hours. Levels of nitrite and nitrate in gastric contents were also increased significantly after LPS administration. The co-administration of N omega-nitro-L-arginine (an inhibitor of NO synthase) and LPS resulted in a marked reduction of urinary levels of nitrate and NTCA, indicating that nitrosation is mediated by NO synthase. These results together suggest that induction of NO synthase by infection with bacteria, parasite and viruses could result in increased endogenous nitrosation not only in the infected tissues but also in the stomach, where nitrosamines would be formed more rapidly under acidic conditions.

X-ray scattering with momentum transfer in the plane of membrane. Application to gramicidin organization

We demonstrate a technique for measuring x-ray (or neutron) scattering with the momentum transfer confined in the plane of membrane, for the purpose of studying lateral organization of proteins and peptides in membrane. Unlike freeze-fracture electron microscopy or atomic force microscopy which requires the membrane to be frozen or fixed, in-plane x-ray scattering can be performed with the membrane maintained in the liquid crystalline state. As an example, the controversial question of whether gramicidin forms aggregates in membrane was investigated. We used dilauroylphosphatidylcholine (DLPC) bilayers containing gramicidin in the molar ratio of 10:1. Very clear scattering curves reflecting gramicidin channel-channel correlation were obtained, even for the sample containing no heavy atoms. Thallium ions bound to gramicidin channels merely increase the magnitude of the scattering curve. Analysis of the data shows that the channels were randomly distributed in the membrane, similar to a computer simulation of freely moving disks in a plane. We suggest that oriented proteins may provide substantial x-ray contrast against the lipid background without requiring heavy-atom labeling. This should open up many possible new experiments.

Detection of the major DNA adducts of benzo[j]fluoranthene in mouse skin: nonclassical dihydrodiol epoxides

Studies have demonstrated that the metabolic activation of benzo[j]fluoranthene (B[j]F) to a genotoxic agent proceeds through the formation of either the trans-4,5-dihydrodiol (B[j]F-4,5-diol) or the trans-9,10-dihydrodiol (B[j]F-9,10-diol) metabolite of B[j]F. Using 32P-postlabeling analysis, the profiles of DNA adducts formed in vivo in mouse skin from B[j]F-4,5-diol and B[j]F-9,10-diol were obtained to establish the contribution of each of these dihydrodiols to the formation of B[j]F-DNA adducts in vivo. B[j]F, B[j]F-4,5-diol and B[j]F-9,10-diol were applied to the shaved backs of mice (100 micrograms/mouse), and DNA adducts were isolated and separated using multidimensional TLC and reverse-phase HPLC. The greatest level of adducts was observed with B[j]F-4,5-diol, which resulted in the formation of 383 pmol of DNA adducts/mg of DNA. This level of DNA modification was more than 2 orders of magnitude greater than that observed with B[j]F or B[j]F-9,10-diol. The major adducts detected from the application of B[j]F-4,5-diol to mouse skin in vivo had chromatographic properties similar to those of the major adducts detected with B[j]F. In contrast, the major DNA adducts detected with B[j]F-9,10-diol had chromatographic properties distinctly different than the adducts formed from either B[j]F or B[j]F-4,5-diol. DNA adducts formed from the syn and anti isomers of the 4,5-dihydrodiol 6,6a-epoxide and the 9,10-dihydrodiol 11,12-epoxide of B[j]F were also evaluated. Each dihydrodiol epoxide derivative was reacted with calf thymus DNA in vitro and applied to mouse skin in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue-specific expression of heat shock proteins of the mouse in the absence of stress

The steady-state levels of four members of the heat shock proteins families (HSP84, HSC73, HSP71, and HSP25) were examined by immunoblot analysis of several different tissues of young and adult mice in the absence of stress. These hsps were detected in all tissues but their level was variable. The levels of HSC73 and HSP84 varied only slightly between different tissues in either young or adult mice, with the exception of skin where these hsps were found in reduced amounts. In contrasts, the stress-inducible member of the HSP70 family, HSP71, was found to be expressed in all tissues but in amounts which differed by as much as two orders of magnitude between tissues. In general, the levels of both HSP71 and HSP25 were found to be tissue dependent, with higher levels found in tissues such as stomach, intestine, colon and bladder, tissues which are exposed to toxic environmental or metabolic products, and which may concentrate these substances by water resorption and/or be exposed to them for longer periods. The levels of HSP71 and HSP25 were generally positively correlated both in young and adult mice although this correlation was not found in certain tissues such as kidney, testes, and bone. Tissues of young mice contained lower amounts of HSP25 and HSP71 than were found in the same tissues from adults. We conclude that hsps are expressed in all tissues of the mouse in the absence of stress and that some organs, particularly those exposed to potentially toxic metabolites, show a higher level of expression of HSP71 and HSP25.

Amplifiable messenger RNA

RNA molecules were prepared that consisted of an mRNA encoding chloramphenicol acetyltransferase embedded within the sequence of midivariant RNA, which is a template for the RNA-directed RNA polymerase Q beta replicase. These recombinant RNAs were shown to be bifunctional: they are amplified exponentially by incubation with Q beta replicase, and the replicated RNA serves as template for the cell-free synthesis of enzymatically active chloramphenicol acetyltransferase. The availability of amplifiable mRNAs will enable relatively large amounts of protein to be synthesized in vitro.

Characterization and developmental expression of chick aortic lysyl oxidase

The complete primary structure of chick lysyl oxidase was determined by recombinant DNA techniques. The nucleotide sequence of contiguous chick lysyl oxidase cDNA clones contained an open reading frame of 1260 bases which encodes a predicted protein of 420 amino acid residues (48,150 Da). In comparison to the deduced primary structure of rat lysyl oxidase, the chick enzyme is larger in size and exhibits a strong conservation of sequence within the latter two thirds of the molecule (92% identity) and a high degree of divergence in the first 150 amino acid residues (60% identity allowing for several insertions in both sequences). The developmental steady-state levels of lysyl oxidase mRNA together with the mRNAs encoding two of the enzyme's substrates (tropoelastin and type I collagen) increased between 8 and 16 days of embryonic development. Although levels of lysyl oxidase mRNA increased during aortic embryogenesis, the specific activity of the enzyme remained fairly constant suggesting that lysyl oxidase activity increases in direct proportion to total protein synthesis and cell number. In situ hybridization showed that the spatial expressions of lysyl oxidase and tropoelastin transcripts differ suggesting that the enzyme and substrate genes are differentially regulated within the cells of the arterial wall.

Study of the effect of lithium on lymphokine-activated killer cell activity and its antitumor growth

The in vitro effect of lithium on lymphokine-activated killer cell (LAK) activity and its in vivo antitumor growth were observed. LAK activity was enhanced when LiCl was added during LAK cell induction, and this enhancement was observed both in human peripheral blood mononuclear cell and in mouse splenocytes used as LAK precursors. Cholera toxin, which can increase intracellular levels of cAMP, decreased LAK cell activity. However, lithium partially reversed this inhibitory effect, indicating that lithium increased LAK cell activity by decreasing cAMP levels. D-Sphingosine, an inhibitor of protein kinase C, and EGTA, a calcium chelator, both inhibited the LAK cell activity. However, their inhibitory effects could not be reversed by lithium because lithium was added in the culture in combination with one of these inhibitors during LAK cell induction. By using slot blot analysis, the effect of lithium on the expression of tumor necrosis factor-alpha mRNA of LAK cells was analyzed. Lithium increased the level of tumor necrosis factor-alpha mRNA when both lithium and interleukin 2 were added to induce LAK cells. The in vivo antitumor effect of lithium has also been studied. Using a mouse melanoma experimental model, the effect of lithium on tumor growth was also observed. Both lithium alone and interleukin 2/LAK had an antitumor effect, whereas the treatment of interleukin 2/LAK in combination with lithium had the strongest inhibitory effect on tumor growth, since this treatment resulted in reduction of tumor size and prolongation of survival in tumor-bearing mice. Therefore, it is hopeful that lithium can be used as a new immunomodulator for cancer immunotherapy and immune diseases.

Catabolite gene activator protein and integration host factor act in concert to regulate tdc operon expression in Escherichia coli

Anaerobic expression of the tdcABC operon of Escherichia coli requires cyclic AMP and the catabolite gene activator protein (CAP). Purified CAP binds to a 30-bp sequence in the tdc promoter between positions -55 and -26, and a mutant CAP site with base substitutions at positions -48, -47, and -45 failed to bind CAP and also drastically reduced the beta-galactosidase expression from a tdcB'-'lacZ fusion plasmid. Recently, we showed that efficient expression of the tdc operon also requires a functional integration host factor (IHF) and an IHF-binding site in the tdc promoter between positions -118 and -88. The levels of beta-galactosidase activity from the tdcB'-'lacZ fusion plasmids were also reduced in an IHF-deficient strain with the wild-type or mutant plasmid CAP sequence. In vitro footprinting experiments revealed that CAP and IHF occupy their specific binding sites on tdc DNA when they are present separately or together. These regulatory proteins also induced significant bending of the tdc promoter DNA. Our results suggest that CAP and IHF act in concert as positive transcription factors for tdc operon expression in vivo.

Placement of a duodenal feeding tube via gastrostoma with fiberoptic bronchoscope

We report a case of esophageal disruption that required a duodenal feeding tube. Because of collapse of the gastric outlet secondary to severe emaciation, several attempts to place a tube into the duodenum via gastrostoma had ended in failure. We finally were able to accomplish it with the aid of a fiberoptic bronchoscope and a Swan-Ganz catheter. The procedure is described and discussed.

Turnover of soluble proteins in the wheat sieve tube

Although the enucleate conducting cells of the phloem are incapable of protein synthesis, phloem exudates characteristically contain low concentrations of soluble proteins. The role of these proteins and their movement into and out of the sieve tubes poses important questions for phloem physiology and for cell-to-cell protein movement via plasmodesmata. The occurrence of protein turnover in sieve tubes was investigated by [(35)S]methionine labeling and by the use of aphid stylets to sample the sieve tube contents at three points along a source-to-sink pathway (flag leaf to grains) in wheat plants (Triticum aestivum L.). Protein concentration and composition were similar at all sampling sites. The kinetics of (35)S-labeling of protein suggested a basically source-to-sink pattern of movement for many proteins. However, an appreciable amount of protein synthesis and, presumably, removal also occurred along the path. This movement appeared to be protein specific and not based on passive molecular sieving. The results have important implications for the transport capacities of plasmodesmata between sieve tubes and companion cells. The observations considerably expand the possible basis for ongoing sieve tube-companion cell interactions and, perhaps, interaction between sources and sinks.

[Research on sterilization of pathogens by high electrostatic voltage method]

An experimental research has been carried out on the sterilization of four kinds of pathogens by high electrostatic method along with an inquiry into the influence of voltage waveform and the treated time on sterilization. It is concluded that pathogens can be killed efficiently by corona discharge field.

The predominant calcimedins from Trypanosoma brucei comprise a family of flagellar EF-hand calcium-binding proteins

The cellular complement of calcimedins was identified in Trypanosoma brucei by Ca(2+)-dependent association with phenyl-Sepharose. Predominant calcimedins with molecular mass of 23-26 kDa and 44 kDa, along with minor calcimedins of 96, 120 and 230 kDa, were obtained. The trypanosome calcimedins were unrelated to vertebrate annexins, based upon antibody cross-reactivity and an inability to associate in a Ca(2+)-dependent way with phospholipid vesicles comprised of phosphatidylserine or phosphatidylethanolamine/phosphatidylcholine (1:1, w/w). Partial sequence analysis demonstrated that 44 kDa calcimedin (Tb-44) contained an EF-hand calcium-binding loop. Five CNBr/tryptic fragments exhibited a total of 93% similarity with Tb-17, a 23 kDa EF-hand protein in T. brucei. The trypanosome calcimedins appeared to comprise a family of proteins, based on sequence similarities and antibody cross-reactivity of affinity-purified anti-Tb44 with the 23-26 kDa cluster. No evidence was found for Tb-44 in the related species T. cruzi, Leishmania taraentolae or Crithidia fasciculata. Antibodies against Tb-44 were localized by immunofluorescence along the flagellum of T. brucei. Immunoblot analysis of flagella-enriched preparations demonstrated that Tb-44 and the 23-26 kDa cluster were present in this structure. We conclude that annexin family members are not among the predominant trypanosome proteins that associate with phenyl-Sepharose in a Ca(2+)-dependent way. Instead, the major trypanosome calcimedins comprise a family of flagellar EF-hand calcium-binding proteins.