Reduction of concentrated nitrate by using in situ synthesized zero-valent copper.

Although zero-valent iron represents a promising approach for reduction of nitrate (NO(3)(-)) in water, its application in concentrated nitrate is limited by surface passivation. In this study, an alternative approach using in situ synthesized zero-valent copper (Cu(0)) produced by borohydride (NaBH(4)) was investigated. Complete reduction was observed within 55 min by reacting 677 mg-N/L of NO(3)(-) with CuO (0.312 g/L) and NaBH(4) (4.16 g/L) at 60 °C. The pseudo-first-order rate constant was 0.059 min(-1), and it increased threefold when the CuO dose was increased to 1.24 g/L. Increasing the NaBH(4) dose produced less nitrite (NO(2)(-)) throughout the experiments, indicating that it is the primary agent for reducing NO(2)(-). The initial pH exerted a significant effect on the reaction rate, and NO(3)(-) was rapidly reduced when the initial pH was less than 4. Based on the research findings, possible reaction pathways for NO(3)(-) reduction by Cu(0) are proposed in this work.

AdeRS combination codes differentiate the response to efflux pump inhibitors in tigecycline-resistant isolates of extensively drug-resistant Acinetobacter baumannii.

Tigecycline (TGC)-resistant extensively drug-resistant Acinetobacter baumannii (XDRAB) is an increasing threat in regard to nosocomial infections. The resistance-nodulation-cell division (RND) efflux pump has played an important role in TGC resistance. In this study, total 81 TGC-resistant XDRAB isolates were analyzed for their responses to the efflux pump inhibitor 1-(1-naphthylmethyl)-piperazine (NMP). We found that NMP could reduce by 4-fold or greater than 4-fold the minimum inhibitory concentration (MIC) of TGC in 45 isolates (55.6 %). After typing with pulsed-field gel electrophoresis (PFGE), group A appeared to be the major cluster with good synergistic response to NMP. Transcripts of the AdeABC efflux pump gene were consistently more correlated with TGC resistance than transcripts of the AdeFGJ or AdeIJK efflux pump genes in these isolates. Of the 81 isolates, the amino acid sequences of AdeR and AdeS were further classified and combined into 31 different codes. Although the dissemination of TGC-resistant XDRAB isolates was genetically diverse in our hospital, their responses to NMP conversion were still strain-dependent. We found that AdeRS combination codes were better than PFGE typing in separating groups of isolates with different sensitivity to NMP conversion.

MiR-638 serves as a tumor suppressor by targeting HOXA9 in glioma.

OBJECTIVE: MiR-638 is constantly downregulated and serves as a tumor suppressor in various cancers. Its role in gliomas remains unclear. This study is designed to investigate the clinical significance and the pathogenic role of miR-638 in human gliomas. PATIENTS AND METHODS: Quantitative Real-time PCR was performed to analyze the expression of miR-638 in the tumor and adjacent tissues of 24 glioma patients. The association between the expression of miR-638 and clinical features were examined. Survival of patients was studied by Kaplan-Meier curves. The impact of miR-638 on cell growth and apoptosis was determined by CCK-8 assay, colony formation assay, cell cycle analysis and Annexin V-FITC-PI apoptosis assay. The effect of miR-638 on HOXA9 was determined by luciferase assay and Western blot. The effect of miR-638 and HOXA9 on expression of oncogenes, Cyclin D1 and C-MYC was determined by Western blot. RESULTS: MiR-638 expression was constantly downregulated in glioma tumor tissue, which is negatively correlated with the WHO grade. MiR-638 expression was associated with clinical features such as tumor size, KPS score and WHO grade. Patients with low miR-638 had a worse overall survival than those with high expression. Experimentally, miR-638 directly targeted HOXA9 to suppress its expression, leading to attenuations of cell proliferation, colony formation and cell cycle progression and enhanced basal apoptosis level. MiR-638/HOXA9 axis also suppressed the expression of Wnt/beta-catenin-regulated oncogenes, Cyclin D1 and C-MYC. CONCLUSIONS: MiR-638 is a constantly downregulated microRNA in gliomas and is associated with its prognosis. MiR-638 regulates cellular malignancy of gliomas through targeting HOXA9. Thus, miR-638/HOXA9 signaling axis may have therapeutic potential in gliomas.

Use of automated riboprinter and pulsed-field gel electrophoresis for epidemiological studies of invasive Haemophilus influenzae in Taiwan.

A total of 87 invasive isolates of Haemophilus influenzae isolated throughout Taiwan from 1994 to 1998 was collected; 57 were from children <14 years old. In all, 60.9% of isolates were resistant to ampicillin and produced beta-lactamase. Ribotyping revealed six different profiles in 55 isolates of type b, nine profiles in 10 isolates of non-type b and 12 profiles in 22 isolates of non-typable H. influenzae. Among isolates from 35 cases of meningitis, 30 (86%) were in ribogroups 1, 2 and 3 with >90% genetic similarity. Compared with all the other ribogroups, ribogroups 1, 2 and 3, which encompassed all H. influenzae type b, were significantly more prevalent as a cause of meningitis in children <14 years old. Further subtyping of the predominant ribogroup by pulsed-field gel electrophoresis (PFGE) identified differences of 0-6 bands among these isolates of ribogroup 1, which indicated distant relatedness. Automated ribotyping was found to be a useful method and was less time-consuming for molecular epidemiology studies of H. influenzae. PFGE is suggested as an addition to ribotyping to improve discrimination if H. influenzae type b is involved. Differentiating ribogroups between type b and non-type b H. influenzae by genotyping may help to understand the molecular characteristics of outbreaks, endemicity and value of vaccination. According to the results of ribotyping and PFGE, it seems possible that spread of invasive H. influenzae type b had occurred and ribotyping confirmed that there was no clonal spread of non-type b H. influenzae in Taiwan.

Database of repetitive elements in complete genomes and data mining using transcription factor binding sites.

Approximately 43% of the human genome is occupied by repetitive elements. Even more, around 51% of the rice genome is occupied by repetitive elements. The analysis presented here indicates that repetitive elements in complete genomes may have been very important in the evolutionary genomics. In this study, a database, called the Repeat Sequence Database, is first designed and implemented to store complete and comprehensive repetitive sequences. See http://rsdb.csie.ncu.edu.tw for more information. The database contains direct, inverted and palindromic repetitive sequences, and each repetitive sequence has a variable length ranging from seven to many hundred nucleotides. The repetitive sequences in the database are explored using a mathematical algorithm to mine rules on how combinations of individual binding sites are distributed among repetitive sequences in the database. Combinations of transcription factor binding sites in the repetitive sequences are obtained and then data mining techniques are applied to mine association rules from these combinations. The discovered associations are further pruned to remove insignificant associations and obtain a set of associations. The mined association rules facilitate efforts to identify gene classes regulated by similar mechanisms and accurately predict regulatory elements. Experiments are performed on several genomes including C. elegans, human chromosome 22, and yeast.

The aging effects on the EMG and mechanical responses of the human wrist flexor stretch reflexes.

The purpose of this study is to investigate the effects of aging on the human stretch reflexes. The EMG and torque responses of the stretch reflex of the wrist flexors were evoked by ramp-and-hold mechanical perturbations. The stretch reflexes were recorded at seven test conditions with different stretch velocity and muscle preload. The test results from young and older healthy adult subjects were compared. In average, the absolute amplitude of the short-latency (20-40 ms) EMG (recorded from flexor carpi radialis) reflex response was significantly lower in the older group. If the data were normalized and expressed in percentage of the maximal voluntary EMG activity, however, this group difference was not significant. There was no change in the reflex gain of the short-latency reflex with aging. For the long-latency (50-90 ms) EMG reflex response, both the normalized amplitude and the reflex gain were significantly enhanced with aging, probably through supraspinal mechanisms. There was no significant difference in the threshold velocity for the evoked EMG reflexive activities between age groups. There were also no changes in the reflexive wrist flexion torque with aging. These results suggested that the number of motor units recruited during the stretch reflex activity declined with aging although the percentage of motor units recruited was not affected by aging. It is concluded that the central regulating mechanisms of the spinal motoneuron excitability are not compromised by aging. The automatic gain compensation phenomenon is also preserved with aging.

Correlation of spasticity with hyperactive stretch reflexes and motor dysfunction in hemiplegia.

OBJECTIVES: To study the correlation between spasticity and motor dysfunction in the wrist-hand unit of adult hemiplegic patients, and to investigate the correlation between clinical spasticity and hyperactive stretch reflexes. STUDY DESIGN: A survey study with a sequential case series of subjects. SETTING: Neuromuscular Research Laboratory, School of Physical Therapy, Texas Woman's University, Houston, TX. SUBJECTS: Sequential sample recruited from local stroke support groups: 10 patients with chronic hemiplegia caused by cerebral vascular accident who had various degrees of spasticity in the wrist joint. OUTCOME MEASURES: Modified Ashworth Scale, amplitudes of stretch reflexes for wrist flexors, grip strength, active range of motion of the wrist joint, and Fugl-Meyer test. RESULTS: Strong reverse correlation was found between spasticity and grip strength, the Fugl-Meyer test scores, and the Box and Blocks test scores (p = .001 to .005). Results also indicated a strong and consistent correlation between spasticity and reflexive electromyographic activities of the stretch reflex recorded from active muscles (p = .005 and .007), but not between spasticity and torque response of the stretch reflex. CONCLUSIONS: The degree of wrist spasticity is associated with impaired hand function in hemiplegic patients, and hyperactive electromyographic response of the stretch reflex, recorded from active muscles, is a valid indicator of spasticity.

Toxicity of methylmercury: effects on different ages of rats.

LD50 of methylmercury chloride has been shown to be dependent on the ages of the rats. As the age increases, the LD50 decreases, i.e. the younger rats could tolerate higher doses of methylmercury than the older one. The LD50 were 39.6 +/- 2.3, 33.1 +/- 2.1, 30.3 +/- 1.0, 27.1 +/- 1.0, 24.7 +/- 1.5 and 23.9 +/- 1.1 mg Hg/kg for the 200 g, 300 g, 350 g, 400 g, 450 g and 500 g rates respectively. The elimination of mercury from blood showed little correspondence to age during the 30 days duration. The onset of neurological symptoms after receiving 25 mg Hg/kg of methylmercury chloride occurred between 8 to 15 days post dosing in the surviving rats. Rats unaffected during the latency period did not show neurological signs if their blood-mercury levels decreased to below 100 ppm. Young and old rats showed marked differences in the distribution of mercury in the blood. In the erythrocyte membrane, the eight week old rats retained a higher concentration of the toxic metal than did the 19.5 week old rats. Also, there was significant differences in the ratios of mercury content in the red blood cells to that of plasma; young rats showing 115:1 and for the old ones being 5:1. The permeability of erythrocyte membrane to mercury might play an important role in the age factors on the suceptibility of methylmercury intoxication.

Effect of stabilization temperature on the degradation of adriamycin in albumin microspheres.

The effect of stabilization temperature on the degradation of adriamycin HCl during the preparation of albumin microspheres was investigated. The degradation of adriamycin HCl by heating at various temperature with different time interval in dried adriamycin HCl powder, adriamycin HCl aqueous solution, wetted Adriablastina (adriamycin HCl with lactose) powder and Adriablastina aqueous solution was also studied. In the presence of water the degradation of adriamycin HCl was found; whereas, in the absence of water no degradation occurred. The degradation of adriamycin HCl in solution and wetted powder showed a zero order reaction. An increase in temperature increased degradation rate. The rate constant for adriamycin HCl degradation in Adriablastina solution obtained was in good agreement with that in adriamycin HCl solution. It was suggested that the presence of lactose had no interference in the degradation of adriamycin HCl. The zero-order reaction of degradation was attributed to the drug behaved like a suspension. The degradation of adriamycin HCl at various stabilization temperature during the preparation of microspheres had the same tendency as those of the adriamycin HCl solution and the wetted adriamycin HCl powder that were heated by the DSC instrument with the condition similar to the preparation of microspheres.

Functional assessment of tibial-nerve recovery in the cat using gait analysis: preliminary study.

The purpose of this study was to investigate gait-pattern changes after complete tibial nerve lesion in the cat, and to observe whether nerve repair could reverse some of the changes. In six cats, a 5-cm segment of the tibial nerve was transected. The nerve gap was then repaired with nerve autograft in three animals and was unrepaired in three as controls. The walking patterns of the cats were videotaped, and the hip, knee, ankle, and metatarsophalangeal joint angles were measured at the beginnings of the F, E1, E2, and E3 phases of the step cycle. Two weeks after surgery, abnormal gait patterns were observed, and four gait parameters (E3.Hip, E3.Ankle, E3.M-P, and F.Ankle) were found to be statistically significantly different from normal. Six months after surgery, the nerve-graft group had gait-parameter values approaching normal, while the control group showed no measurable improvement. Correspondingly, electrophysiologic testing revealed considerable nerve regeneration in the nerve-graft group but not in the control group. It was concluded that these gait parameters can be used as valid functional indices to evaluate the degree of tibial nerve recovery in the cat model.

Ankle stance angle: a functional index for the evaluation of sciatic nerve recovery after complete transection.

This study attempted to develop a motor functional index, ankle stance angle (ASA), to assess rat sciatic nerve regeneration subsequent to autografting. ASA, 50 degrees in normal rats, is the ankle joint angle at the mid-stance phase of the gait cycle. In a nerve graft group, a 1-cm segment of the right sciatic nerve was transected and then repaired with nerve autograft. In an ungrafted group, the nerve gap was left unrepaired. ASA measured 4 months after surgery was statistically significantly larger in the nerve graft group (36 degrees) than in the ungrafted group (22 degrees). The results suggest that ASA is more sensitive than sciatic function index in detecting functional recovery after a complete sciatic nerve lesion. ASA also showed a significant correlation with the passive range of ankle joint motion and gastrocnemius muscle weight. The study concluded that ASA is a reliable index for assessment of regeneration of rat sciatic nerve after a complete lesion. The intra-rater reliability (r = 0.97 and 0.90) and inter-rater reliability (r = 0.85) tests performed support the conclusions.

Detection of 20-hydroxyeicosatetraenoic acid in rat urine.

20-Hydroxyeicosatetraenoic acid (20-HETE), an arachidonate metabolite of the cytochrome P450 omega hydroxylase, was detected in rat urine by gas chromatography-mass spectrometric techniques. The concentration of 20-HETE in urine from 7-week-old hypertensive and normotensive rats was 2.1 and 1.3 nM, respectively. This is the first demonstration of 20-HETE urinary excretion and thus calls attention to the possibility that 20-HETE participates in the regulation of renal function via its effect on vascular tone and ion transport processes.

Do the reticulocyte maturation fractions and bone marrow reticulocyte count further help the classification of anemias?

BACKGROUND: Reticulocyte count plays a major role in anemic evaluation. The conventional method done by the manual supravital staining cannot subclassify the group of less than 2% of corrected reticulocyte count. The newly-developed flow cytometer provides different maturation fractions by measuring its fluorescent intensity. The reticulocytes are believed to shift to the circulation from the bone marrow earlier in more severe anemia. Therefore, the purpose of this study is to evaluate the role of reticulocyte maturation fractions and bone marrow reticulocyte in anemia classification. METHODS: By using a fully automated counter, the roles of the reticulocyte with maturation and their shifting from bone marrow were evaluated in anemias. Different groups of subjects (243 in total) including aplastic, nutritional, and infiltrative anemias and anemia due to excess destruction and blood loss were studied. Each subject had bone marrow examination for morphologic diagnosis and reticulocyte evaluation. RESULTS: Both the absolute count and the maturation fractions of reticulocytes showed significant difference among marrow infiltration, aplastic anemia, and hemolytic anemia. Both the absolute reticulocyte count and less mature fractions were lowest in aplastic group. The marrow reticulocyte counts and shift ratio to circulating blood added little benefit in the classification of anemias. CONCLUSIONS: The automated reticulocyte count with maturation fractions helps classify anemias, particularly for those with low reticulocyte count by the manual method.

High-level expression of ampC beta-lactamase due to insertion of nucleotides between -10 and -35 promoter sequences in Escherichia coli clinical isolates: cases not responsive to extended-spectrum-cephalosporin treatment.

Two Escherichia coli isolates were recovered from the blood of two cancer patients and were demonstrated to produce high levels of the AmpC beta-lactamase with isoelectric points of >9.0. The hypertranscription of ampC RNA was observed by Northern blot hybridization in both isolates. One isolate (isolate EC44) had a point mutation (G-->A at position -28) and insertion of thymidine between positions -20 and -19 of the ampC promoter gene (GenBank accession no. AE000487). The single nucleotide insertion of T between positions -19 and -20 created an optimal distance (17 bp) in the Pribnow box for ampC hyperproduction. The other isolate (isolate EC38) had two point mutations (G-->A at position -28 and C-->T at position +58) and a 2-base (GT) insertion between positions -14 and -15. Although the insertion of GT between positions -14 and -15 may create a new promoter next to the original promoter, cloning of the ampC region with truncated nucleotides of the original -35 region of EC38 failed to verify the hypothesis that a new promoter would be created by such a nucleotide insertion. Instead, multiple start sites for ampC transcription at -1, +1, +2, and +3 were observed in an S1 nuclease protection assay. These results suggest that the RNA polymerase is flexible in the selection of a start site in ampC hypertranscription. In conclusion, nucleotide insertions between the -35 and -10 ampC promoter sequences was the mechanism for the hyperproduction of AmpC beta-lactamase and resistance to oxyimino-cephalosporins. The failure of the two patients to respond to treatment with oxyimino-cephalosporins highlights the important role of such a resistance mechanism in the clinical setting.

Serum IgE, skin and radioallergosorbent tests for house dust and mites in asthmatic children.

Thirty asthmatic children were given an intradermal skin test, total IgE measurements and the radioallergosorbent test (RAST) against house dust and house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae). Results of the intradermal skin test and RAST were highly positive with overall agreement in 95.6%. The correlation coefficient between the total IgE and the RAST to house dust was 0.35 (p less than 0.05). There was no significant difference between the total IgE and the RAST to D. pteronyssinus and D. farinae (p greater than 0.05). The highly significant correlation coefficient between house dust and house dust mites (D. farinae, p less than 0.0001; D. pteronyssinus, p less than 0.00001) was determined by RAST. House dust has been found to be the most important allergen in children in Taiwan. The role of mites as a possible allergen in house dust also showed a highly significant correlation in our study.

Induction of megakaryocytic differentiation in a newly established human leukemic cell line by 12-o-tetradecanoylphorbol-13-acetate.

BACKGROUND: Biological studies on megakaryopoiesis have been hampered by the scarcity of megakaryocytes in normal bone marrow and difficulty in long term culture. Alternatively, leukemic cell lines with megakaryocytic differentiation potential may provide good models to counter these problems. METHODS: Leukemic cells from a patient with acute megakaryocytic leukemia were put into long-term culture and established into a cell line which was designated as VGH-MK1. The VGH-MK1 cells were challenged with differentiation agents and/or cytokines, and the differentiation of these cells was examined using morphological, immunocytochemical and surface-marker studies. RESULTS: Morphologically, VGH-MK1 cells had prominent nucleoli and basophilic cytoplasm with some protrusions, but large cells were occasionally seen. Under regular culture condition, the cells had a doubling time of 36-48 hours. The cloned cell line exhibited markers characteristic of megakaryoblasts after differentiation induction. Specifically, when stimulated with 12-o-tetradecanoylphorbol-13-acetate (TPA), cells became larger and had large or multinuclei. They were induced to express platelet glycoproteins GPIb (CD42b), GPIIb/IIIa (CD41), and GPIIIa (CD61) antigens, but not erythroid nor lymphoid markers. Platelet peroxidase (PPO) activity was also induced. Retinoic acid did not exhibit similar differentiation-inducing effects. In contrast, it counteracted the effects induced by TPA. CONCLUSIONS: An unique human leukemic cell line, VGH-MK1, has been established here. It could be induced to exhibit some characteristics of megakaryocytic lineage, and may be an useful model for the biological studies of megakaryopoiesis.

Expression of DNA topoisomerase II alpha and multidrug resistance p-glycoprotein in acute leukemia.

BACKGROUND: Drug resistance is a major cause of treatment failure in acute leukemia. Overexpression of multidrug resistance gene and decreased activity of topoisomerase II alpha are suggested as two important mechanisms for this resistance. METHODS: We used immunohistochemical method to determine the expressions of both topoisomerase II alpha (topo II alpha) and p-glycoprotein (gp-170) in bone marrow biopsy specimens from 68 cases of acute leukemia. Patients were divided into four groups: (1) leukemia cells with high score for topo II alpha and negative for gp-170; (2) leukemia cells with high score for topo II alpha and positive for gp-170; (3) leukemia cells with low score for topo II alpha and negative for gp-170; and (4) leukemia cells with low score for topo II alpha and positive for gp-170. The clinical responses were then followed as routine, and the clinical correlation was evaluated by analysis of variance and Pearson Chi-Square test. RESULTS: The measure of the single parameter (either topo II alpha or gp-170 alone) did not show a significant difference in the overall survival. However, the complete response rate was much higher in the first group patients whose bone marrow reading score was high in topo II alpha and negative for gp-170 expression. Survival duration increased with the increase in the complete response rate. CONCLUSIONS: Combined parameters of topo II alpha and gp-170 are more useful than any individual parameter for the prognosis of acute leukemia.

[The significance of mite antigens in Kawasaki disease].

House dust mites have been suspected as a causative agent in Kawasaki disease. To assess the role of mite in children with Kawasaki disease, we studied 20 cases of Kawasaki disease from September 1985 through May 1986. Their ages ranged from 2 months to 4 years with a mean of 2.1 years, we assessed intradermal skin test reactivity to mite antigens (Dermatophagoides pteronyssinus and Dermatophagoides farinae) and anti-mites specific IgE (RAST) levels in 20 Kawasaki disease patients, 10 children for control, and 30 asthmatic patients for comparison. Intradermal skin test reactivity to mite antigens was not significantly increased in the 20 Kawasaki disease patients than in pediatric controls (p greater than 0.05), there was a more significantly reactivity in asthmatic patients than in Kawasaki disease and pediatric control (p less than 0.001). There was a correlation between serum IgE and anti-D. pteronyssinus specific IgE (r = 0.65, p less than 0.001) or anti-D. farinae specific IgE (r = 0.73, p less than 0.001) in Kawasaki disease. The anti-mite specific IgE's expressed as RAST score or mean values were not more significantly raised in Kawasaki disease than in pediatric controls (p greater than 0.05), there was a more significantly raised in asthmatic patients than in Kawasaki disease patients and in pediatric control. Coronary artery involvement was not significantly related to anti-mite specific IgE's in Kawasaki disease (p greater than 0.05). According to this study, the role of house dust mites is undetermined to Kawasaki disease.