[Maxillofacial injury: clinical analysis of 284 cases]

Maxillofacial injury is common in war or in the routine life. Always accompanying trauma of other sites of the body, it has its own characters and leads to serious outcome. This article made a clinical analysis of 284 cases of maxillofacial injury from following aspects: onset of wounded, characters and chief complications of maxillofacial soft and hard tissues injury and foreign bodies left in place. The authors also discussed their experiences at emergency management.

Investigations of peptide hydration using NMR and molecular dynamics simulations: A study of effects of water on the conformation and dynamics of antamanide

The influence of water binding on the conformational dynamics of the cyclic decapeptide antamanide dissolved in the model lipophilic environment chloroform is investigated by NMR relaxation measurements. The water-peptide complex has a lifetime of 35 μs at 250 K, which is longer than typical lifetimes of water-peptide complexes reported in aqueous solution. In addition, there is a rapid intracomplex mobility that probably involves librational motions of the bound water or water molecules hopping between different binding sites. Water binding restricts the flexibility of antamanide. The experimental findings are compared with GROMOS molecular dynamics simulations of antamanide with up to eight bound water molecules. Within the simulation time of 600 ps, no water molecule leaves the complex. Additionally, the simulations show a reduced flexibility for the complex in comparison with uncomplexed antamanide. Thus, there is a qualitative agreement between the experimental NMR results and the computer simulations.

Studies on prophylactic effect of artesunate on schistosomiasis japonica

OBJECTIVE

To examine the prophylactic effect of artesunate on schistosomiasis japonica by killing schistosomula.

METHODS

Mice, rabbits and dogs after infection with cercariae of schistosoma japonicum (S. japonicum) were treated with artesunate on the 7th day at a dose of 300 mg/kg, 20-40 mg/kg and 30 mg/kg respectively once a week for 4-6 weeks. A double-blind test was used. A total of 864 persons in highly endemic areas for schistosomiasis were administered either artesunate at a dose of 6 mg/kg once a week for 8 weeks or identical placebo with the same dose-schedule during transmission season for S. japonicum. Four weeks after the last dosing, fecal examinations for S. japonicum eggs and miracidia were carried out to evaluate the prophylactic effect.

RESULTS

Worm reduction rates in mice, rabbits and dogs were 77.50-90.66%, 99.53% and 97.10% respectively. All of the 467 residents in 2 trials were free from eggs or miracidia upon stool examinations whereas in the control groups with placebo, 15 out of 218 (6.9%) and 26 out of 179 (14.5%) were stool eggs and/or miracidia positive in the first and second trial, respectively. Side effects were mild. No significant changes in routine blood and urine tests, electrocardiogram, hepatic and renal functions were observed after artesunate administration.

CONCLUSIONS

Animal experiments and field trials have demonstrated good efficacy of artesunate on killing schistosomula with little side effects. Thus, the drug is suggested to be used on the population in endemic areas for prevention of schistosomiasis.

[Water soluble contents of Chinese drug beimu, the bulbs of Fritillaria plants]

Based on platelet aggregation induced by platelet activating factor (PAF), the active fraction with inhibiting effect was screened from four species of Chinese drung Beimu, the bulbs of Fritillaria przewalskii, F. ussurienis, F. anhuiensis and F. thunbergii. According to the experimental results, the active water soluble fraction of F. ussuriensis was further studied. Two nucleosides, thymidine and adenosine were isolated. Platelet aggregation assay shows that adenosine is the chief aggregation inhibitor with 1% = 42 at 5 microns. It is suggested that nucleosides may be the other type of active constituent besides alkaloids in the Fritillaria plants.

Molecular cloning and characterization of the human xanthine dehydrogenase gene (XDH)

Xanthine dehydrogenase (XDH, EC 1.1.1.204) is a rate-limiting enzyme in the oxidative metabolism of purines and is thought to play a key role in a variety of pathophysiologic processes including ischemiasolidusreperfusion injury, viral pneumonia, and renal failure. We herein report the isolation and characterization of the human XDH gene. The gene is composed of 36 exons and 35 introns and spans at least 60 kb. The exon sizes range from 53 to 279 bp, and the intron sizes range from 0.2 to over 8 kb. Using primer extension and RNase protection analyses, two transcriptional initiation sites were identified 59 and 82 nucleotides upstream of the ATG start codon. One Goldberg-Hogness box (ATTTAT)-like sequence was found 24 bp upstream from the second transcriptional initiation site, and two inverted CCAAT sequences were found 19 and 42 bp upstream from the second transcriptional initiation sites. A relative GC-enriched region was found between -55 and -121. Approximately 2 kb of the 5'-flanking region was sequenced, and a variety of putative regulatory elements were identified including CsolidusEBP binding sites, IL-6 and NF-kappaB sites, and potential TNF-RE, IFN-gamma-RE, and IL-1-RE sites.

Seven members of the (1→3)-β-glucanase gene family in barley (Hordeum vulgare) are clustered on the long arm of chromosome 3 (3HL)

Members of the (1→3)-β-glucan glucanohydrolase (EC 3.2.1.39) gene family have been mapped on the barley genome using three doubled haploid populations and seven wheat-barley addition lines. Specific probes or polymerase chain reaction (PCR) primers were generated for the seven barley (1→3)-β-glucanase genes for which cDNA or genomic clones are currently available. The seven genes are all located on the long arm of chromosome 3 (3HL), and genes encoding isoenzymes GI, GII, GIII, GIV, GV and GVII (ABG2) are clustered in a region less than 20 cM in length. The region is flanked by the RFLP marker MWG2099 on the proximal side and the Barley Yellow Mosaic Virus (BYMV) resistance gene ym4 at the distal end. The gene encoding isoenzyme GVI lies approximately 50 cM outside this cluster, towards the centromere. With the exception of the gene encoding isoenzyme GIV, all of the (1→3)-β-glucanase genes are represented by single copies on the barley genome. The probe for the isoenzyme GIV gene hybridized with four DNA bands during Southern blot analysis, only one of which could be incorporated into the consensus linkage map.

Characterization of a lactate oxidase from a strain of gram negative bacterium from soil

A lactate oxidase was purified about 36-fold from a newly screened strain KY6 of gram negative bacterium from soil to yield a homogeneous protein. The native enzyme had a molecular mass of 204 kDa measured by Sephadex G-200 and that of subunit on the SDS-PAGE was found to be 45 kDa. The enzyme was optimally active at pH 7.7 and showed stability at pH range of 5.7 to 9.5 for 24 h at 4 degrees C. The optimum temperature was 70 degrees C and the enzyme activity was stable for 10 min up to 45 degrees C. The half-life of the enzyme activity was about 10 min at 55 degrees C. The best substrate of the enzyme was D-lactate and Km value for D-lactate was 0.14 mM. The Km value for DL-lactate was 0.20 mM. Substrate inhibition of the enzyme was observed at higher concentrations than 20 mM of DL-lactate and 10 mM of D-lactate.

Stress-induced hemodynamic and hemostatic changes in patients with systemic hypertension: effect of verapamil

Stress-induced hemodynamic and hemostatic responses may acutely trigger atherosclerotic plaque disruption and thrombosis leading to myocardial infarction. This study was designed to evaluate the responses to three stressors and to determine if once-daily sustained release verapamil (Verelan) modified these responses. We studied 13 patients with mild to moderate hypertension in a randomized, double-blind, placebo-controlled crossover trial. After 4 weeks of therapy, patients were evaluated following assumption of the upright posture, mental stress, and cold pressor test. During placebo, the stressors produced an increase in systolic pressure (144 +/- 2 to 167 +/- 3 mmHg, p < 0.001), heart rate (70 +/- 2 to 77 +/- 2 beats/ min, p < 0.001), and platelet aggregability to adenosine diphosphate (threshold concentration fell from 2.8 +/- 0.4 to 1.9 +/- 0.1 microM, p = 0.05) and epinephrine (3.4 +/- 0.9 to 1.6 +/- 0.6 microM, p < 0.001). Verapamil lowered systolic pressure at baseline (144 +/- 2 to 134 +/- 2 mmHg, p < 0.001), and after stress (167 +/- 3 to 154 +/- 3 mmHg, p < 0.001), but did not alter the absolute increase with stress. During verapamil, platelet reactivity did not increase with stress, and the post-stress response to epinephrine was reduced (higher threshold concentration) compared with placebo (3.9 +/- 1.3 vs. 1.5 +/- 0.3 microM, p = 0.05). Verapamil also reduced the response to collagen (increased lag time) at baseline and after stress (111 +/- 9 vs. 91 +/- 3 s, p < 0.01). We conclude that verapamil blunted potentially harmful stress-induced hemodynamic and hemostatic changes. Further studies are required to determine whether these effects translate into a lower incidence of acute cardiovascular events.

Modelling for waste water treatment by Rhodopseudomonas palustris Y6 immobilized on fibre in a columnar bioreactor

A kinetic model of continuous treatment of waste water by Rhodopseudomonas palustris Y6 immobilized on soft fibre in a columnar bioreaction system was established. Good agreement was found between the model prediction and the experimental data from continuous operation [initial chemical oxygen demand (COD) concentration = 29.700 g/l] of the system. The optimum operational conditions for the maximum COD reduction capacity were investigated from the model prediction and the experimental data. The waste water treatment process may significantly increase the waste reduction capacity because a large amount of active biomass for COD reduction is immobilized in the system, resulting in operation stability. The results presented here provide a useful basis for further scaling up and efficient operation of waste water treatment processes.

Improvement of tracheal autograft survival with transplantation into the greater omentum

BACKGROUND

Reconstruction of tracheal defects with tracheal grafts is not practicable clinically because the problem of tracheal graft revascularization has not been solved successfully. We conducted experiments to investigate efficacy of implanting tracheal graft into the greater omentum for revascularization and possibility of adopting staged transplantation procedure for repair of tracheal defect.

METHODS

Twenty-four mongrel dogs were randomly and equally divided into groups I and II. Six-ring cervical tracheal segments were harvested as autografts. The grafts were wrapped with the omentum and placed into the peritoneal cavity in group I, and reimplanted with omentopexy in group II. Four grafts were examined macroscopically, microscopically, and 35S-autoradiographically on postoperative days 3, 7, and 14, respectively.

RESULTS

Epithelium loss was evident in the mucosas of the grafts except the 4 from group I. Percentages of viable chondrocytes assessed with 35S-autoradiography were significantly higher in tracheal grafts from group I than group II. All tracheal grafts with their own omental pedicles could be brought to any portions of the trachea.

CONCLUSIONS

We conclude that prior implantation of tracheal graft in the omentum is beneficial for preservation of its structure, and reconstruction of a tracheal defect with a tracheal graft implanted first into the omentum is feasible.

[Synthesis of substituted benzeneseleninic acid and its antineoplastic activity]

In view of the negative relationship between selenium and cancer, we designed and synthesized eleven substituted benzeneselenic acids (IVa-k) The antineoplastic activity of the title compounds was evaluated via the tests of inhibition of acetylcholinesterase, HL-60 and K562 in vitro, and Ehrlich carcinoma in mice. The result showed that the compounds IVa and IVb had distinct antineoplastic activity. The life span increase rate of IVb on mice bearing Ehrlich carcinoma was 20.30% (20mg/kg), which was higher than the increase rate of sodium selenite (10.65%, 0.5mg/kg).

Identification of Acan125 as a myosin-I-binding protein present with myosin-I on cellular organelles of Acanthamoeba

We have discovered the first protein to bind to a non-filamentous myosin, aside from actin. This protein, Acan125, is a 125-kDa protein from Acanthamoeba that associates with the SH3 domain of Acanthamoeba myosin-IC and not the SH3 domain of human fodrin. Antibodies raised against Acan125 recognize a single protein of 125 kDa from a whole cell lysate of Acanthamoeba; antibodies to myosin-I (M1.7 and M1.8) do not recognize Acan125 on the same blot. Double labeling of Acanthamoeba show Acan125 and myosin-I to be present on the same intracellular organelle, most likely amoebastomes. Immunoprecipitation with either anti-myosin-I or anti-Acan125 antibodies coprecipitates both Acan125 and myosin-I from a lysate of Acanthamoeba, demonstrating that Acan125 interacts with native myosin-I.

Study of aging of silicone rubber biomaterials with NMR

Multinuclear nuclear magnetic resonance (NMR) spectroscopy (29Si, 13C, 1H) is used to characterize the aging process of silicone rubber-based biomaterials in a rat model. 1H NMR relaxation measurements (spin-lattice, T1, and spin-spin, T2, relaxation times) were performed to better understand the molecular dynamics of polysiloxane chains in implants. After 1 year of implantation in animals, changes in the 1H T2 relaxation times and the NMR spectra were observed in polydimethylsiloxane, Silastic sheets and chin implants, while these measurements remain unchanged in finger joints. Very small amounts of fat were detected in all types of silicone rubber implants at the end of the implantation period. This work shows that free silicone migrates from the implants to adjacent tissues and distant sites, such as spleen or liver, and is chemically modified.

cDNA sequence and gene locus of the human retinal phosphoinositide-specific phospholipase-C beta 4 (PLCB4)

Defects in the Drosophila norpA (no receptor potential A) gene encoding a phosphoinositide-specific phospholipase C (PLC) block invertebrate phototransduction and lead to retinal degeneration. The mammalian homolog, PLCB4, is expressed in rat brain, bovine cerebellum, and the bovine retina in several splice variants. To determine a possible role of PLCB4 gene defects in human disease, we isolated several overlapping cDNA clones from a human retina library. The composite cDNA sequence predicts a human PLC beta 4 polypeptide of 1022 amino acid residues (MW 117,000). This PLC beta 4 variant lacks a 165-amino-acid N-terminal domain characteristic for the rat brain isoforms, but has a distinct putative exon 1 unique for human and bovine retina isoforms. A PLC beta 4 monospecific antibody detected a major (130 kDa) and a minor (160 kDa) isoform in retina homogenates. Somatic cell hybrids and deletion panels were used to localize the PCLB4 gene to the short arm of chromosome 20. The gene was further sublocalized to 20p12 by fluorescence in situ hybridization.

Modulation of skeletal muscle sodium channels by human myotonin protein kinase

In myotonic muscular dystrophy, abnormal muscle Na currents underlie myotonic discharges. Since the myotonic muscular dystrophy gene encodes a product, human myotonin protein kinase, with structural similarity to protein kinases, we tested the idea that human myotonin protein kinase modulates skeletal muscle Na channels. Coexpression of human myotonin protein kinase with rat skeletal muscle Na channels in Xenopus oocytes reduced the amplitude of Na currents and accelerated current decay. The effect required the presence of a potential phosphorylation site in the inactivation mechanism of the channel. The mutation responsible for human disease, trinucleotide repeats in the 3' untranslated region, did not prevent the effect. The consequence of an abnormal amount of the kinase would be altered muscle cell excitability, consistent with the clinical finding of myotonia in myotonic dystrophy.

Association between increased estrogen status and increased fibrinolytic potential in the Framingham Offspring Study

BACKGROUND

Although extensive evidence indicates that estrogen is responsible for the markedly decreased cardiovascular risk of premenopausal women, the mechanism through which estrogen might exert its protective effect has not been adequately explained. Since thrombosis is now recognized to play an important role in the onset of cardiovascular disease, we investigated the relation between estrogen status and fibrinolytic potential, a determinant of thrombotic risk.

METHODS AND RESULTS

We determined levels of plasminogen activator inhibitor (PAI-1) antigen and tissue plasminogen activator (TPA) antigen in 1431 subjects from the Framingham Offspring Study. Fibrinolytic potential was compared between subjects with high estrogen status (premenopausal women and postmenopausal women receiving hormone replacement therapy) and low estrogen status (men and postmenopausal women not receiving hormone replacement therapy). In all comparisons, subjects with high estrogen status had greater fibrinolytic potential (lower PAI-1 levels) than subjects with low estrogen status. First, postmenopausal women receiving estrogen replacement therapy had lower levels of PAI-1 than those not receiving therapy (13.0 +/- 0.5 versus 19.5 +/- 1.0 ng/mL, P < .001). Second, premenopausal women had lower levels of PAI-1 than men of a similar age (14.8 +/- 0.6 versus 20.3 +/- 0.8 ng/mL, P < .001); this sex difference diminished when postmenopausal women not receiving hormone replacement therapy were compared with men of a similar age (19.6 +/- 0.7 versus 21.1 +/- 0.7 ng/mL, P = .089). Third, premenopausal women had markedly lower levels of PAI-1 antigen than postmenopausal women not receiving estrogen therapy (14.8 +/- 0.6 versus 19.5 +/- 1.0 ng/mL, P < .001). The between-group differences observed for TPA antigen were similar to those for PAI-1 antigen.

CONCLUSIONS

Each of these comparisons indicates that the cardioprotective effect of estrogen may be mediated, in part, by an increase in fibrinolytic potential. These findings might provide at least a partial explanation for the protection against cardiovascular disease experienced by premenopausal women, and the loss of that protection following menopause.

Assignment of human xanthine dehydrogenase gene to chromosome 2p22

Xanthine dehydrogenase (XDH, EC 1.1.1.204) oxidizes a variety of purines, pterins, and other heterogenic nitrogen compounds, serving as a rate-limiting enzyme in nucleic acid degradation. The genetic defect of XDH results in hereditary xanthinuria and other disorders in purine metabolism. Based on the cloning and sequencing results of human XDH cDNA in our laboratory, we studied the localization and sublocalization of the XDH gene. A Version 3.0 human-hamster somatic cell hybrid PCRable DNA panel and specific PCR primers derived from human XDH cDNA for amplification were used to assign the XDH gene to human chromosome 2. The fidelity of the PCR product was confirmed by nucleotide sequencing the PCR product. The assignment of the XDH gene to chromosome 2 at band p22 was established by fluorescence in situ hybridization on human metaphase chromosomes using a clone from a pWE 15 cosmid library containing the XDH gene. The results should be useful for further studies of the molecular basis for hereditary xanthinuria and other genetic disorders related to abnormal XDH activity.

Red sensitivity of dichromated cellulose triacetate as a holographic recording material

The red sensitivity of dichromated cellulose triacetate holographic recording material without any dye sensitization is reported. We suggest that the sensitivity is due to the absorption at 590 nm of the intermediate Cr(V) formed in the reducing process of chromium from Cr(VI) to Cr(III). In the experiment, the real-time transmission gratings are recorded with 632.8-nm irradiation from a He-Ne laser.

Heterologous expression of cDNAs encoding barley (Hordeum vulgare) (1-->3)-beta-glucanase isoenzyme GV

Two cDNAs have been isolated from libraries generated from poly(A)+RNA of young barley roots and leaves, using a cDNA encoding barley (1-->3)-beta-glucanase isoenzyme GII as a probe. Nucleotide sequence analyses and ribonuclease protection assays show that the two cDNAs differ only in the length of their 3'-untranslated regions; the corresponding mRNAs are likely to originate from a single gene by tissue-specific processing at separate polyadenylation sites. When the coding region of the cDNA is expressed in E. coli, the resultant protein catalyses the hydrolysis of (1-->3)-beta-glucan with an action pattern characteristic of a (1-->3)-beta-glucan endohydrolase (EC 3.2.1.39). The enzyme has been designated isoenzyme GV of the barley (1-->3)-beta-glucanase family).

Na-independent Cl(-)-HCO3- exchange mediates recovery of pHi from alkalosis in guinea pig ventricular myocytes

The pH-sensitive fluorescent indicator, carboxy-seminaphthorhodafluor 1 (SNARF 1) was used to assess the contribution of forward Na-independent Cl(-)-HCO3- exchange (1 external Cl- exchanged for 1 internal HCO3-) to intracellular pH (pHi) recovery from alkalosis in adult ventricular myocytes (guinea pig). Intracellular alkalosis was elicited by external application of the weak base, trimethylamine. In the absence of CO2-HCO3- (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered solution) the initial rate of pHi recovery from alkalosis (pHi = 7.25-7.75) was slow and independent of pHi, yielding an apparent net HCO3- efflux of 0.36 +/- 0.11 mM/min. In CO2-HCO3(-)-buffered solution, the initial rate of pHi recovery and net HCO3- efflux were much faster and markedly increased by raising pHi. At pHi approximately 7.25, net HCO3- efflux was approximately 2 mM/min and rose to 9 mM/min at pHi approximately 7.6. 4,4'-Diisothiocyanostilbene-2,2'-disulfonic acid (0.4 mM) decreased net HCO3- efflux by 78.1 +/- 8.9% in CO2-HCO3(-)-buffered solution. Reduction in extracellular Cl- concentration from 135 to 20 mM markedly slowed the rate of pHi recovery from alkalosis and reduced net HCO3- efflux. pHi recovery from alkalosis was unaffected by removal of external sodium or exposure to 1 mM amiloride. These results indicate that forward Na-independent Cl(-)-HCO3- exchange mediates pHi recovery from alkalosis in guinea pig ventricular myocytes.

[Immunohistochemical study on fibrin in brain traumas]

The fibrin formation in brain traumas was studied by immunohistochemical method. Eleven cases of brain trauma were examined. The fibrin was demonstrated not only in the areas of brain contusion and the neuronal cytoplasm of hypothalamus, thalamus, brainstem, and cerebellum, but also on the membrane of endothelial cells and red blood cells within some capillaries. The fibrin was also found around capillaries and the areas far from the brain trauma. It was suggested that injuries to the brain occurred not only in the local areas of the brain subjected to the violence, but also in the areas far from the local injury. It meant that the brain injuries were not local, but diffuse. The fibrin observed in the neuronal cytoplasm, and on the membrane of endothelial cells and red blood cells within some capillaries was a sign of ante mortem brain traumas. The combined HE staining and immunohistochemical staining of the fibrin is useful in the demonstration of simple brainstem traumas.

[Synthesis of terephthalic acid derivatives and their activity on human promyelocytic leukaemia cells HL-60]

There were 13 derivatives of terephthalic acid were synthesized, in which 9 compounds were not found in literature. The 9 compounds were evaluated for their differentiation-inducing activities on human promyelocytic leukaemia cells HL-60. Compounds N1 and N4 possessed potential activity. Their percentage of differentiating effect was 55% (5 x 10(-6) mol/L), but it was less than that of retinoic acid (79%, 10(-7) mol/L).

Molecular cloning, tissue expression of human xanthine dehydrogenase

Xanthine dehydrogenase (XDH, EC 1.1.1.204) is a molybdenum iron-sulphur flavin hydroxylase which oxidizes a variety of purines, pterins and other heterogenic nitrogen compounds, serving as a rate-limiting enzyme in nucleic acid degradation. In this work, we have isolated and sequenced cDNA clones of human liver XDH. The obtained cDNA covers 4577 bases of human liver XDH mRNA with a 63 bp 5'-end untranslated region and a 515 bp 3'-end untranslated region. A termination codon TGA and a polyadenylation signal AATAAA were identified. An open reading frame encodes 1333 amino acid residues. The assignment of the N-terminal was confirmed by directly sequencing that region of purified human milk XDH. Northern blot analysis shows that the human XDH gene is widely expressed in human tissues.

[Synthesis of p-substituted benzoylaminobenzoic acid (methyl esters) and its differentiation induction in activities of human promyelocytic leukemia cells HL-60]

Sixteen p-substituted benzoylaminobenzoic acids and their methyl esters were synthesized, of which nine were not found in literature. All of the topic compounds were evaluated for their differentiation induction in activities of human promyelotic leukemia cells HL-60. Compounds III1, III2, III4, and III5 possessed potential activities. The differentiation rate, of III4 and III5 was 70% respectively. But it was less than that of retinoic acid (97%).

Generation of reovirus core-like particles in cells infected with hybrid vaccinia viruses that express genome segments L1, L2, L3, and S2

When mouse L fibroblasts are infected with various combinations of recombinant vaccinia viruses possessing thymidine kinase (TK) genes with inserted reovirus genes that encode core components, particles are formed that closely resemble reovirus cores. In cells infected with vaccinia viruses that express reovirus proteins lambda 1 and sigma 2, particles are formed that are very similar to reovirus core shells; if, in addition, the cells are also infected with vaccinia virus that expresses protein lambda 2, particles are formed that also possess the characteristic icosahedrally located projections/spikes that are present on reovirus cores. If, in either case, the cells are also infected with vaccinia virus that expresses the reovirus RNA polymerase, protein lambda 3, the resultant particles are morphologically identical with those formed in its absence, but also contain protein lambda 3.

urbs1, a gene regulating siderophore biosynthesis in Ustilago maydis, encodes a protein similar to the erythroid transcription factor GATA-1

Ustilago maydis secretes ferrichrome-type siderophores, ferric-ion-binding compounds, in response to iron starvation. TA2701, a non-enterobactin-producing, non-ferrichrome-utilizing mutant of Salmonella typhimurium LT-2, was employed as a biological indicator in a novel screening method to isolate three N-methyl-N'-nitro-N-nitrosoguanidine-induced U. maydis mutants defective in the regulation of ferrichrome-type siderophore biosynthesis. These mutants displayed a constitutive phenotype; they produced siderophores in the presence of iron concentrations that would typically repress siderophore synthesis in wild-type strains. A 4.8-kb fragment of U. maydis genomic DNA capable of restoring normal regulation of siderophore biosynthesis in the constitutive mutants was identified. This segment of DNA contains an intronless open reading frame that specifies a protein of 950 amino acids containing two finger motifs similar to those found in the erythroid transcription factor GATA-1. Disruption of this open reading frame in a wild-type strain gave rise to cells that produced siderophores constitutively. Genetic studies indicated that the disruption mutation was allelic to the chemically induced mutations, confirming that the structural gene for a regulator rather than a suppressor gene had been cloned. Northern (RNA) analysis of the gene revealed a 4.2-kb transcript that is expressed constitutively at low levels in wild-type cells. The data support the hypothesis that this gene, which we designate urbs1 (Ustilago regulator of biosynthesis of siderophores), acts directly or indirectly to repress biosynthesis of siderophores in U. maydis.

Conformational backbone dynamics of the cyclic decapeptide antamanide. Application of a new multiconformational search algorithm based on NMR data

A general procedure for the analysis of biomolecular structures by NMR in the presence of rapid conformational dynamics has been applied to the study of the cyclic decapeptide antamanide. Two-dimensional experiments, relaxation measurements in the rotating frame, and homo- and heteronuclear coupling constant determinations have been used to characterize the dynamic properties of the molecule, in combination with a novel search algorithm for investigating multiconformational equilibria. Direct evidence for the presence of a conformational exchange process with an activation energy of approximately 20 kJ mol-1 and an exchange lifetime of approximately 25 microseconds at 320 K has been obtained from rotating frame relaxation measurements. This evidence is combined with the information derived from the multiconformational search algorithm MEDUSA to propose sets of structures that coexist in a dynamic exchange equilibrium.

Increased lipoprotein (a) as an independent risk factor for cardiovascular and cerebrovascular diseases

We quantified serum lipoprotein(a) [Lp(a)] in 1266 healthy persons and established the reference value of Lp(a) in groups of age and sex. The Lp(a) in myocardial infarction (MI) survivors, stroke and primary hypertension patients were determined in comparison with that of age-matched normal controls. Moreover, cholesterol, triglyceride, HDL-cholesterol, apo Al and apo B were measured. The Lp(a) concentrations were not correlated with other lipids in normal controls and patients. Our results suggest that increased Lp(a) is an independent risk factor for MI and stroke patients. The total detective rate of abnormal lipids in MI and stroke patients was as high as 50% and 53.8% (Lp(a) excluded) as well as 65.7% and 64.9% (Lp(a) included) respectively.

Post-transcriptional control of cell type-specific gene expression in bundle sheath and mesophyll chloroplasts of Amaranthus hypochondriacus

Plants that utilize the highly efficient C4 photosynthetic pathway possess two types of specialized leaf cells, the mesophyll and bundle sheath. In mature leaves of amaranth, a dicotyledonous C4 plant, ribulose 1,5-bisphosphate carboxylase (Rubisco) is localized specifically to the chloroplasts of bundle sheath cells, and is not present in the chloroplasts of mesophyll cells. The cell type-specific expression of the chloroplast-encoded Rubisco large subunit (rbcL) gene, and other representative chloroplastic genes, was investigated by using separated bundle sheath and mesophyll chloroplasts prepared from mature amaranth leaves. One-dimensional SDS-polyacrylamide gel electrophoresis revealed several differences in the polypeptide compositions of the two chloroplast types. Western analysis demonstrated that, as in the intact leaves, the Rubisco LSU polypeptide was present only in chloroplast preparations from bundle sheath cells. Pyruvate orthophosphate dikinase (PPdK), a nuclear-encoded chloroplastic enzyme, was found only in the mesophyll chloroplast preparations. rbcL mRNA was present only in the bundle sheath chloroplast preparations, whereas transcripts for the chloroplast-encoded psbA, psaA-B, and rpl2 genes were present in both chloroplast types. Although the rbcL message accumulated only in bundle sheath chloroplasts, run-on transcription analysis indicated that the rbcL gene was transcribed in both bundle sheath and mesophyll chloroplast preparations. Therefore, differential rbcL gene expression in the isolated C4 chloroplasts is regulated, at least in part, at the post-transcriptional level. Possibly this control is mediated by differential processing or stabilization of the rbcL transcript.

[Determination of glycyrrhizin in glycyrrhiza and it's preparations by ion-pair HPLC]

Glycyrrhizin is the main component of glycyrrhiza. In this article an Ion-pair high performance liquid chromatography (HPLC) method is described for the determination of glycyrrhizin in two kinds of glycyrrhiza from different origins and twelve kinds of Chinese traditional patent medicine containing glycyrrhiza. A reversed phase system was used, including an ODS column with water and methanol (36:64) as the mobile phase which contained 5mmol/L tetra-n-butyl ammonium hydroxide and was adjusted to pH 6.0 by phosphoric acid. The column temperature was 35 degrees C; the detection was performed at 254 nm. Under this condition glycyrrhizin could be separated from other components. The limit of detection was 13ng, and the average recovery was 99.85%. During the experiments, we studied the concentration of counter-ion, the mixing ratio of methanol to water, the pH of the mobile phase and column temperature and their effect on the capacity factor of compound and resolution. We also studied the method of pre-treatment for the samples. The determination method is simple and accurate.

Evolution and differential expression of the (1-->3)-beta-glucan endohydrolase-encoding gene family in barley, Hordeum vulgare

The (1-->3)-beta-D-glucan glucanohydrolases [(1-->3)-GGH; EC 3.2.1.39] of barley (Hordeum vulgare L., cv Clipper) are encoded by a small gene family. Amino acid sequences deduced from cDNA and genomic clones for six members of the family exhibit overall positional identities ranging from 44% to 78%. Specific DNA and oligodeoxyribonucleotide (oligo) probes have been used to demonstrate that the (1-->3)-GGH-encoding genes are differentially transcribed in young roots, young leaves and the aleurone of germinated grain. The high degree of sequence homology, coupled with characteristic patterns of codon usage and insertion of a single intron at a highly conserved position in the signal peptide region, indicate that the genes have shared a common evolutionary history. Similar structural features in genes encoding barley (1-->3,1-->4)-beta-glucan 4-glucanohydrolases [(1-->3,1-->4)-GGH; EC 3.2.1.73] further indicate that the (1-->3)-GGHs and (1-->3,1-->4)-GGHs are derived from a single 'super' gene family, in which genes encoding enzymes with related yet quite distinct substrate specificities have evolved, with an associated specialization of function. The (1-->3,1-->4)-GGHs mediate in plant cell wall metabolism through their ability to hydrolyse the (1-->3,1-->4)-beta-glucans that are the major constituents in barley walls, while the (1-->3)-GGHs, which are unable to degrade the plant (1-->3,1-->4)-beta-glucans, can hydrolyse the (1-->3)- and (1-->3,1-->6)-beta-glucans of fungal cell walls.

Purification, characterization and gene structure of (1-->3)-beta-glucanase isoenzyme GIII from barley (Hordeum vulgare)

A new member of the barley (1-->3)-beta-glucan glucanohydrolase family of enzymes has been purified from extracts of germinated grain and young seedlings by fractional precipitation with ammonium sulphate, ion-exchange chromatography, chromatofocussing and gel-filtration chromatography. The enzyme, which has been designated (1-->3)-beta-glucanase isoenzyme GIII, is a basic protein with an apparent molecular mass of 32 000 Da. Oligosaccharide products released by the enzyme during hydrolysis of the (1-->3)-beta-glucan, laminarin, indicate that the enzyme is an endohydrolase. A 2349-bp fragment of barley genomic DNA has been isolated and identified as the gene encoding the (1-->3)-beta-glucanase isoenzyme GIII. The open reading frame encoding the isoenzyme is interrupted by a single intron of 180 bp that splits a codon in the putative signal-peptide region. Northern-blot analyses with gene-specific probes indicate that the (1-->3)-beta-glucanase isoenzyme GIII mRNA accumulates in developing leaves; no mRNA transcripts were detected in the aleurone or scutellum of germinated grain, or in mature vegetative tissues. Although plant (1-->3)-beta-glucanases are generally classified as 'pathogenesis-related' proteins, the physiological function of the barley (1-->3)-beta-glucanase isoenzyme GIII is unclear.

Association of Phosphatidylinositol 4-Kinase with the Plant Cytoskeleton

In eukaryotic cells, phosphatidylinositol 4-hydroxy kinase and phosphatidylinositol-4-phosphate 5-hydroxy kinase are responsible for the formation of the two second messenger precursors phosphatidylinositol-4-phosphate (Ptdlns(4)P) and phosphatidylinositol-4,5-bisphosphate (Ptdlns(4,5)P2). In plant cells, these kinases have been considered to be exclusively membrane associated, with the majority of activity residing in the inner leaflet of the plasmalemma. By sequentially extracting carrot protoplasts with the detergent Nonidet P-40 then more rigorously with Triton X-100, we were able to remove the activity of three separate plasma membrane marker enzymes and to demonstrate that a significant proportion of cellular Ptdlns 4-kinase is associated with the cytoskeleton. When only endogenous substrates were present, Nonidet P-40-permeabilized protoplasts and Nonidet P-40-extracted cytoskeletons displayed a pattern of lipid phosphorylation similar to that obtained with isolated plant membranes or permeabilized cells, whereas the Triton X-100-extracted cytoskeletons showed little or no activity. In contrast, when exogenous substrates were added, a major proportion of PtdlnsP formed was due to kinase activity associated with the cytoskeleton as well as nuclei. However, by subtracting the activity of isolated nuclei, it could be demonstrated that a significant proportion of the detergent-resistant Ptdlns kinase activity resides with the cytoskeletal fraction. These findings suggest that the pathways of polyphosphoinositide biosynthesis in plant cells should be reevaluated to take account of the cytoskeleton and that Ptdlns(4)P itself may play a unique role in modulation of plant cytoskeletal integrity and cellular signal transduction.

[Lipoprotein (alpha) as a risk factor for myocardial infarction]

Serum lipoprotein (alpha) [Lp(alpha)]was determined in 105 cases of myocardial infarction survivors (MIS). Lp(alpha) level in MIS was much more elevated as compared with that in healthy subjects and in a hypertension group. Lp(alpha) had no relation with apolipoprotein B and AI, cholesterol, triglyceride and high density lipoprotein cholesterol. It may be a significant and independent risk factor for coronary heart disease.

Delayed-focus pulses for magnetic resonance imaging: an evolutionary approach

An evolutionary algorithm has been used to design a family of shaped radiofrequency pulses giving uniform absorption-mode excitation across a predetermined frequency band. By allowing a free precession interval before signal acquisition, time is left for field gradients to be switched and for undesirable transients to decay.

[Synthesis of hexamethyl propylamine oxime and comparative study of its diastereoisomers]

This is a report on the synthesis of hexamethyl-propylene-amine oxime (HM-PAO), a new agent for regional cerebral blood flow (gamma CBF) imaging, the separation of its diastereoisomers (dl- and meso-HM-PAO), and a comparative study of three forms of Tc- 99m labelled HM-PAO (dl-, meso- and mixture-) in chromatography, mice biodistribution and rabbit imaging. The results showed that the Rf value of Tc-99m-dl-HM-PAO (0.8-1.0) on silica G thin layer chromatography with MEK as solvent was different from that of Tc-99m-meso-HM-PAO (0.6-0.8), and that the retention of dl- isomer in the brain was higher and more static than those of meso-and mixture HM-PAO but identical with Ceretec, a dl-HM-PAO kit manufactured by Amersham Inc., England. The primary clinical applications for gamma CBF SPECT imaging demonstrated a satisfactory result.

[Effect of radix Astragalus on the contents of collagen in the aorta and lung of old rats]

The result of experiments shows that the collagen contents in the aorta and lung of old rats are higher than in those of young rats, whereas the contents in the old rats given Radix Astragalus appear lower than those in the control group, close to those in young rats.