Room temperature quantum cascade lasers with 22% wall plug efficiency in continuous-wave operation

We report the demonstration of quantum cascade lasers (QCLs) with improved efficiency emitting at a wavelength of 4.9 µm in pulsed and continuous-wave (CW) operation. Based on an established design and guided by simulation, the number of QCL-emitting stages is increased in order to realize a 29.3% wall plug efficiency (WPE) in pulsed operation at room temperature. With proper fabrication and packaging, a 5-mm-long, 8-µm-wide QCL with a buried ridge waveguide is capable of 22% CW WPE and 5.6 W CW output power at room temperature. This corresponds to an extremely high optical density at the output facet of ∼35 MW/cm², without any damage.

[Preliminary investigation of gender assignment in 46,XY disorders of sex development with severe male undermasculinisation]

Objective: To explore the feasibility of gender assignment in 46,XY disorders of sex development (DSD) with severe undermasculinisation mainly based on molecular diagnosis. Methods: A retrospective study of 45 patients of 46, XY DSD with severe undermasculinisation were admitted between November 2015 and October 2018 at Children's Hospital, Zhejiang University School of Medicine. The initial social gender were all female, of whom the external genital manifestations were Prader 0 to 2; the degree of masculinity was scored using external masculinisation score (EMS); the position and development of the gonads were examined by ultrasound, cystoscopy and laparoscopy, also including assessing the development of the Wolffian tube and the Müllerian tube. The level and ratio of testosterone to dihydrotestosterone before and after hCG stimulation were evaluated for the function of Leydig cell and 5α-reductase-2. Gender role scales and sandbox games were used to assess gender role behavior. Genital sensitivity to androgen stimulation was assessed; A panel including 163 genes related to gender development were determined by second-generation sequencing in all 45 patients. Finally, a multidisciplinary team (MDT) makes a gender assignment after a comprehensive analysis mainly based on the molecular etiological diagnosis. Results: Thirty-nine out of 45 patients (87%) had an identifiable genetic etiology, and the remaining 6 (13%) were negative for genetic testing. Forty-five patients had EMS less than or equal to 3 points. Sexual psychological assessment was performed in 39 patients, with male dominance in 24 (62%) and female dominance in 15 (38%). The gender assignment was 23 cases (51%) for male and 19 cases (42%) for female, and 3 cases (7%) were not completely determined. Conclusions: Molecular diagnosis provides a strong basis for appropriate gender assignment of 46, XY DSD children with severe undermasculinisation. Based on molecular diagnosis, each DSD should be analyzed by professional MDT to analyze the clinical symptoms/signs, gonadal development, gonad tumor risk, external genital morphology, sexual psychological assessment, potential fertility opportunities, parental views, Social and cultural factors, etc. make appropriate gender assignment.

Serum total bilirubin levels are negatively correlated with metabolic syndrome in aged Chinese women: a community-based study

We evaluated serum total bilirubin levels as a predictor for metabolic syndrome (MetS) and investigated the relationship between serum total bilirubin levels and MetS prevalence. This cross-sectional study included 1728 participants over 65 years of age from Eastern China. Anthropometric data, lifestyle information, and previous medical history were collected. We then measured serum levels of fasting blood-glucose, total cholesterol, triglycerides, and total bilirubin, as well as alanine aminotransferase activity. The prevalence of MetS and each of its individual component were calculated per quartile of total bilirubin level. Logistic regression was used to assess the correlation between serum total bilirubin levels and MetS. Total bilirubin level in the women who did not have MetS was significantly higher than in those who had MetS (P<0.001). Serum total bilirubin quartiles were linearly and negatively correlated with MetS prevalence and hypertriglyceridemia (HTG) in females (P<0.005). Logistic regression showed that serum total bilirubin was an independent predictor of MetS for females (OR: 0.910, 95%CI: 0.863-0.960; P=0.001). The present study suggests that physiological levels of serum total bilirubin might be an independent risk factor for aged Chinese women, and the prevalence of MetS and HTG are negatively correlated to serum total bilirubin levels.

Platelet-to-lymphocyte ratio acts as an independent risk factor for patients with hepatitis B virus-related hepatocellular carcinoma who received transarterial chemoembolization

OBJECTIVE

Hepatocellular carcinoma (HCC) is a common cause of tumor-related deaths worldwide. Previous studies have shown that increased systemic inflammation and platelet-to-lymphocyte ratio (PLR) are associated with poor prognosis of various cancers. The objective of the present study was to investigate the effects of pretreatment PLR on survival in patients with hepatitis B virus (HBV)-related HCC who underwent repeated transarterial chemoembolization (TACE).

PATIENTS AND METHODS

A total of 122 patients with HBV-related HCC who underwent TACE from two centers in the central China were analyzed retrospectively and were separated into two groups based on the median value of neutrophil-to-lymphocyte ratio (NLR; low: < 2.61 or high: ≥ 2.61) and PLR (low: < 96.13 or high: ≥ 96.13).

RESULTS

Patients with low pretreatment PLR and NLR had a higher rate of overall survival compared with patients with a high PLR and NLR (log-rank test). Univariate analyses indicated that a high PLR was a significant risk factor for poor survival (p = 0.022), and multivariate analyses further showed that a high PLR was an independent factor that predicted worse survival (p = 0.001).

CONCLUSIONS

We suggest that a high pretreatment PLR is a useful prognosticator for poor survival in patients with HBV-related HCC undergoing TACE.

EBV-miR-BART7-3p promotes the EMT and metastasis of nasopharyngeal carcinoma cells by suppressing the tumor suppressor PTEN

The epithelial-mesenchymal transition (EMT) is crucial to cancer progression and metastasis. Although multiple cellular miRNAs have been identified to regulate the EMT and metastasis in cancers, the role of viral miRNAs in cancer progression remains largely unknown. Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignancy typically characterized by its early metastasis. In the present study, we have discovered the involvement of a viral miRNA, EBV-miR-BART7-3p, in the EMT and metastasis of NPC cells. Initially, we observed that EBV-miR-BART7-3p was highly expressed in NPC and positively correlated with lymph node metastasis and clinical stage of NPC. Subsequently, we demonstrated that EBV-miR-BART7-3p enhanced cell migration/invasion in vitro, cancer metastasis in vivo, and particularly the EMT characterized by loss of epithelial markers and gain of mesenchymal features in NPC cells. Furthermore, mechanistic studies disclosed that EBV-miR-BART7-3p targeted a major human tumor suppressor PTEN, modulating PI3K/Akt/GSK-3β signaling and eventually leading to the high expression and nuclear accumulation of Snail and β-catenin, which favor EMT. Knockdown of PTEN could phenocopy the effect of EBV-miR-BART7-3p, whereas re-expression of PTEN resulted in a phenotypic reversion. Moreover, these findings were supported by an observation of an EBV-positive cell model in which silencing of endogenous EBV-miR-BART7-3p partially attenuated cell migration/invasion and altered EMT protein expression pattern via reverting PI3K/Akt, Snail and β-catenin expression. Thus, this study suggests a novel mechanism by which EBV-miR-BART7-3p modulates the EMT and metastasis of NPC cells, and a clinical implication of EBV-miR-BART7-3p as a potential biomarker or therapeutic target.

Characterization of new microsatellites selected from EST resources of Chinese mitten crab, Eriocheir sinensis

Sixteen new microsatellites were, identified by screening 7533 expressed sequence tags of Chinese mitten crab, Eriocheir sinensis from GenBank data we published. They were polymorphic with the PIC value ranged from 0.349 to 0.957, the number of alleles ranged from 22 to 48, and the observed and expected heterozygosities ranged from 0.375 to 1.000 and 0.366 to 0.983, respectively. Five loci could be applicable to genetic diversity and population structure of E. sinensis.

IMM-H004, a novel coumarin derivative compound, protects against amyloid beta-induced neurotoxicity through a mitochondrial-dependent pathway

We have investigated the effect of IMM-H004 (7-hydroxy-5-methoxy-4-methyl-3-(4-methylpiperazin-1-yl)-2H-chromen-2-one), a coumarin derivative, on the amyloid beta (Aβ)-induced neurotoxicity in primary culture cortical neurons and pheochromocytoma (PC12) cells. Our results showed that treatment with IMM-H004 markedly reduced the number of apoptotic cells after exposure to Aβ25-35 or Aβ1-42, determined by MTT, TUNEL staining and Flow cytometry. Further study indicated that IMM-H004 significantly inhibited Aβ-induced cytotoxicity and apoptosis by reversing Aβ-induced mitochondrial dysfunction, including MMP (mitochondrial membrane potential) decrease, reactive oxygen species production, and mitochondrial release of cytochrome c. IMM-H004 can regulate the interaction between Bax and Bcl-2, decreased levels of p53 and active caspase-3 protein induced by Aβ25-35. Furthermore, IMM-H004 also reduced translocation of AIF (apoptosis-inducing factor) induced by Aβ25-35. These results demonstrated that IMM-H004 was capable of protecting neuronal cells from Aβ-induced degeneration through a mitochondrial-dependent apoptotic pathway. The results of this study lend further credence to the notion that IMM-H004 is a 'multipotent therapeutic agrent' that reduces toxic levels of brain Aβ, and holds the potential to protect neuronal mitochondrial function in Alzheimer's disease.

Predominant etiology of adnexal torsion and ovarian outcome after detorsion in premenarchal girls

BACKGROUND/PURPOSE

Consensus has not been reached regarding the treatment of ovarian torsion in premenarchal girls. If viable adnexa can be salvaged, the future reproductive potential of the girl is maximized. The authors determined the predominant etiology, evaluated the restoration of ovarian function and anatomic structure postoperatively in premenarchal girls with adnexal torsion, and discuss the most appropriate treatment.

METHODS

Sixty-six premenarchal girls with twisted adnexa underwent salpingoophorectomy (27 cases), or detorsion and adnexal conservation surgery (39 cases), according to the extent of adnexal damage found intraoperatively. These patients' data were collected and analyzed. The typical presentation, predominant etiology, surgical outcome, and restoration of ovarian function postoperatively were investigated.

RESULTS

Of all torsive ovaries, histopathology verified that 2 (3.0%) cases were malignant, 8 (12.1%) cases were normal, and 56 (84.9%) cases were benign. After operation and menarche, ultrasound showed that the involved ovaries were of normal size with normal follicular development in 33 of the 35 (94.3%) patients who received detorsion and adnexal conservation surgery. In the remaining two (5.7%) of the 35 detorsion patients, the affected ovaries were atrophied (small sized) and there was no ultrasound evidence of follicular development.

CONCLUSIONS

Premenarchal girls with adnexal torsion more commonly had a benign ovarian tumor or no underlying abnormality as an etiology; ovarian malignancy was rare. In the management of these cases, detorsion and adnexal conservation surgery should be considered in cases with adnexa appearing to be ischemic or hemorrhagic infarction.

Long-wavelength emission InAs quantum dots grown on InGaAs metamorphic buffers

In this work, InAs quantum dots (QDs) grown on a linear graded InGaAs metamorphic buffer layer by molecular beam epitaxy have been investigated. The growth of the metamorphic buffer layers was carefully optimized, yielding a smooth surface with a minimum root mean square of roughness of less than 0.98 nm as measured by atomic force microscopy (AFM). InAs QDs were then grown on the buffer layers, and their emission wavelength at room-temperature is 1.49 microm as measured by photoluminescence (PL). The effects of post-growth rapid thermal annealing (RTA) on the optical properties of the InAs QDs were investigated. After the RTA, the PL peak of the QDs was blue-shifted and the full width at half maximum decreased.

Iterative active deformational methodology for tumor delineation: Evaluation across radiation treatment stage and volume

PURPOSE

To introduce, implement, and assess an iterative modification to the active deformational image segmentation method as applied to cervical cancer tumors.

MATERIALS AND METHODS

A comparison by Jaccard similarity (JS) between this active deformational method and manual segmentation was performed on tumors of various sizes across preradiation, 3 weeks postradiation, and 6 weeks postradiation using a General Linear Mixed Model across 121 studies from 52 patients with Stage IIB-IV cervical cancers.

RESULTS

The deformable segmentation method produced promising levels of agreement including JS factors of 0.71+/-0.11 in the preradiation studies. The analysis illustrated a rate of improvement in JS with increasing tumor volume that differed between the preradiation and 6 weeks postradiation stage (P=0.0474). In the large preradiated tumors each additional cm3 of volume was associated with an increase or improvement in JS of 0.0008 (95% confidence interval [CI]: 0.0003, 0.0014). In the smaller postradiation tumors, each additional cm3 of volume was associated with a more robust improvement in JS of 0.0046 (95% CI: 0.0009, 0.0082).

CONCLUSION

Agreement was strongly affected by tumor volume, and its performance was most impacted across volume in the later stages of radiation therapy. The deformation-based segmentation method appears to demonstrate utility for delineating cervical cancer tumors, particularly in the earliest stages of radiation treatment, where agreement is greatest.

Angle-dependent light emission from aligned multiwalled carbon nanotubes under CO(2) laser irradiation

This paper reports the light emission from aligned multiwalled carbon nanotubes (MWNTs) under continuous wave CO(2) laser (λ = 10.6 µm) irradiation. Results indicate that the light emission is dependent on the angle θ between the laser incident direction and the nanotube axis. The relative intensity of the light emission at certain wavelengths shows a Lorentzian feature when θ varies from 0° to 90°. The Lorentzian fitting curve displays a distinct tendency between shorter (λ<600 nm) and longer wavelength (λ>700 nm). A minimum intensity was observed at θ(m) close to 67° under shorter wavelength, whereas a maximum intensity was shown at θ(m) of about 60° at longer wavelength. These results show the anisotropic property of aligned MWNTs.

Pressure-induced transition in magnetoresistance of single-walled carbon nanotubes

We applied hydrostatic pressure (up to 10 GPa) to single-walled carbon nanotube bundles at low temperature (down to 2 K) to measure their magnetoresistance (MR) in a field up to 12 T. We found a pressure-induced transition in MR from positive to negative in the high-field regime. The onset of the transition occurs at approximately 1.5 GPa, which correlates closely with the tube shape transitions. The characteristics of the high-pressure MR are consistent with a model of pressure-induced two-dimensional weak localization.

Characterization of microsatellite loci in fulvous fruit bat Rousettus leschenaulti

Rousettus leschenaulti is an abundant species in many countries of South‐East Asia, including south China. We isolated seven microsatellite loci in R. leschenaulti from genomic DNA enriched for CA repeats with the enriched library method. A total of 56 samples from a population in the Guangxi Province of China were tested with these microsatellite markers. The polymorphism ranged from seven to 16 alleles, and the observed heterozygosity was 84–94%. It is the first time microsatellite markers were characterized from R. leschenaulti, and these markers can be an important tool for analysing population structure and genotypic diversity.

Determining incidence of extended spectrum β-lactamase producing Enterobacteriaceae, vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus in 38 centres from 17 countries: the PEARLS study 2001–2002

The PEARLS study prospectively monitored selected nosocomial pathogens from 38 centres in 13 European, three Middle Eastern countries and South Africa during 2001-2002. Extended spectrum beta-lactamase (ESBL) production rates among Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp. were 5.4% (142/2609), 18.2% (401/2,206) and 8.8% (204/2,328), respectively, for all study sites. The overall ESBL production rate for the combined Enterobacteriaceae was 10.5% (747/7,143), highest in Egypt, 38.5%, and Greece, 27.4%, and lowest in The Netherlands, 2.0%, and Germany, 2.6%. IEF, PCR and DNA sequencing determined 10.7% false positives among Enterobacter spp. when using NCCLS guidelines to screen for ESBL production. The prevalence of nosocomial methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium was 32.4% (294/908) and 8.7% (83/949), respectively. PEARLS provides baseline data against which prospective changes in resistant determinants and outcomes can be measured in this ongoing study.

Major form of NUP98/HOXC11 fusion in adult AML with t(11;12)(p15;q13) translocation exhibits aberrant trans-regulatory activity

Three adult patients with de novo acute myeloid leukemia of distinct subtypes harboring t(11;12)(p15;q13) have been investigated to characterize the genes involved in that translocation. Through molecular cytogenetics, a chromosome break was detected at the 3' part of nucleoporin 98 (NUP98) gene at 11p15. Using rapid amplification of cDNA end, we identified the partner gene at 12q13, HOXC11. Molecular analysis showed that exon 12 of NUP98 was fused in-frame to exon 2 of HOXC11 in all three cases with t(11;12)(p15;q13). Therefore, this type of fusion may represent the major form of the NUP98-HOXC11 chimera so far reported. Moreover, two out of three cases had a confirmed deletion of the 3' part of NUP98 gene and more telomeric region of 11p harboring a group of tumor-suppressor genes. Interestingly, the NUP98-HOXC11 protein when assayed in a GAL4 reporter system, showed an aberrant trans-regulatory activity as compared to the wild-type HOXC11 in both COS-7 and HL-60 cells. Therefore, NUP98-HOXC11 may contribute to the leukemogenesis by interfering with the cellular mechanism of transcriptional regulation.

Direct synthesis of long single-walled carbon nanotube strands

In the processes that are used to produce single-walled nanotubes (electric arc, laser ablation, and chemical vapor deposition), the typical lengths of tangled nanotube bundles reach several tens of micrometers. We report that long nanotube strands, up to several centimeters in length, consisting of aligned single-walled nanotubes can be synthesized by the catalytic pyrolysis of n-hexane with an enhanced vertical floating technique. The long strands of nanotubes assemble continuously from arrays of nanotubes, which are intrinsically long.

Superior mesenteric arteriovenous fistula associated with portal obstruction

Superior mesenteric arteriovenous fistula is rarely encountered. Unrecognized in early stage, it can cause hazardous sequelae of portal hypertension. Herein we report a rare case of portal obstruction associated with an aneurysmal dilatation of the superior mesenteric vein, which was caused by a superior mesenteric arteriovenous fistula. The patient was a 74-year-old woman admitted for continuous hemetemesis, presenting with a palpable abdominal mass. The computed tomogram revealed a 6.5 cm superior mesenteric venous aneurysm and thrombotic portal venous obstruction. On account of impending shock, an emergent portal venous thrombectomy and portocaval shunt was carried out. Superior mesenteric arterial angiography performed 4 months later confirmed the diagnosis. Being without symptoms, the patient was clinically followed and remained in stable condition for 3 and a half years. The clinical presentation of a mesenteric arteriovenous fistula varies, with occasional gastrointestinal tract hemorrhage. When complicated with portal obstruction, the condition can be disastrous. We believe that creation of a porto-systemic shunt with resection of the arterio-venous fistula is the proper treatment. This patient is now under close observation.

Molecular cloning and characterization of a novel mammalian endo-apyrase (LALP1)

Here we describe the cloning, localization, and characterization of a novel mammalian endo-apyrase (LALP1) in human and mouse. The predicted human LALP1 gene encodes a 604-amino acid protein, whereas the mouse Lalp1 gene encodes a 606-amino acid protein. The human and mouse genes have 88% amino acid sequence identity. These genes share considerable homologies with hLALP70, a recently discovered mammalian lysosomal endo-apyrase. The human LALP1 gene resides on chromosome 10q23-q24 and contains 12 exons and 11 introns covering a genomic region of approximately 46 kilobase pairs. The subcellular localization and enzymatic activity of LALP1 indicated that LALP1 is indeed an endo-apyrase with substrate preference for nucleoside triphosphates UTP, GTP, and CTP.

Coiled coil region of streptokinase gamma-domain is essential for plasminogen activation

The specific functions of the amino acid residues in the streptokinase (SK) gamma-domain were analyzed by studying the interactions of human plasminogen (HPlg) and SK mutants prepared by charge-to-alanine mutagenesis. SK with mutations of groups of amino acids outside the coiled coil region of SK gamma-domain, SK(K278A,K279A,E281A,K282A), and SK(D360A,R363A) had similar HPlg activator activities as wild-type SK. However, significant changes of the functions of SK with mutations within the coiled coil region were observed. Both SK(D322A,R324A,D325A) and SK(R330A,D331A,K332A,K334A) had decreased amounts of complex formation with microplasminogen and failed to activate HPlg. SK(D328A,R330A) had a 21-fold reduced catalytic efficiency for HPlg activation. The studies of SK with single amino acid mutation to Ala demonstrate that Arg(324), Asp(325), Lys(332), and Lys(334) play important roles in the formation of a HPlg.SK complex. On the other hand, amino acid residues Asp(322), Asp(328), and Arg(330) of SK are involved in the virgin enzyme induction. Potential contact between Lys(332) of SK and Glu(623) of human microplasmin and strong interactions between Asp(328) and Lys(330), Asp(331) and Lys(334), and Asp(322) and Lys(334) of SK are noticed. These interactions are important in maintaining a coiled coil conformation. Therefore, we conclude that the coiled coil region of SK gamma-domain, SK(Leu(314)-Ala(342)), plays very important roles in HPlg activation by participating in virgin enzyme induction and stabilizing the activator complex.

Terephthalaldehyde bis(thiosemicarbazone) bis(dimethylformamide) solvate

The thiosemicarbazone molecule in C(10)H(12)N(6)S(2).2C(3)H(7)NO has -1 symmetry. The thiosemicarbazone moiety and the benzene ring are essentially coplanar, with mean and maximum deviations of 0.03 and 0. 11 A, respectively. The dimethylformamide molecules bridge the thiosemicarbazone moieties, forming two-dimensional sheets through N-H.O hydrogen bonds.

Measurement of wave chaotic eigenfunctions in the time-reversal symmetry-breaking crossover regime

We present experimental results on eigenfunctions of a wave chaotic system in the continuous crossover regime between time-reversal symmetric and time-reversal symmetry-broken states. The statistical properties of the eigenfunctions of a two-dimensional microwave resonator are analyzed as a function of an experimentally determined time-reversal symmetry-breaking parameter. We test four theories of one-point eigenfunction statistics and introduce a new theory relating the one-point and two-point statistical properties in the crossover regime. We also find a universal correlation between the one-point and two-point statistical parameters for the crossover eigenfunctions.

Preparation of a novel streptokinase mutant with improved stability

The novel mutant streptokinase, SK-K59E, can activate human plasminogen as efficiently as the purified commercially available streptokinase. Several peptide bonds including Lys59-Ser60 in native streptokinase were hydrolyzed in reaction with plasmin and peptides of small molecular masses were generated. The plasminogen activator activity of native streptokinase in reaction with human plasmin declined to 25% of the original activity in a 120-min incubation. On the other hand, the NH2-terminal peptide of SK-K59E remained intact in reaction with plasmin and the activator activity of streptokinase decreased to 75% of the original activity in 120 min. The major degraded peptide fragments of native streptokinase in reaction with plasmin had molecular masses of 36 and 30 kDa. However, two major peptide fragments of 42 and 34 kDa were observed in the reaction of SK-K59E with human plasmin. The 42 kDa peptide fragment, which contained NH2-terminal of streptokinase, could activate human plasminogen as efficiently as the native streptokinase. SK-K59E can induce greater degree of caseinolysis and fibrinolysis than the native streptokinase. In conclusion, the results demonstrate that the prevention of cleavage at Lys59 of streptokinase prolongs the half-life of streptokinase in complex with plasmin and that the NH2-terminal of streptokinase (Ile1-Lys59) plays an important role in maintaining its stability.

Plasminogen activation by streptokinase via a unique mechanism

The mechanism of human plasminogen (HPlg) activation by streptokinase (SK)-type activator was investigated with recombinant truncated SK peptides. An enzyme-substrate intermediate of HPlg.SK. HPlg ternary complex was demonstrated by a sandwich-binding experiment. Formation of the ternary complex was saturable, HPlg-specific, and inhibited by 6-aminocaproic acid. Three interaction sites between SK and HPlg were demonstrated. SK-(220-414) bound to HPlg with two binding sites: one to the micro-HPlg region, the catalytic domain of HPlg, and one to the kringle 1-5 region, with Kd values of 1.50 x 10(-7) and 2.44 x 10(-6) M, respectively. SK-(16-251) bound to a single site on the kringle 1-5 region of HPlg with a Kd of 4.09 x 10(-7) M. SK-(220-414) and SK-(16-251) competed for binding on the same or nearby location on the human kringle 1-5 domain. Combination of SK-(220-414) and SK-(16-251), but not either peptide alone, could effectively activate HPlg. In addition, SK-(16-251) dose-dependently enhanced the activation of HPlg by SK-(16-414), while the HPlg activation by SK-(16-414) was inhibited by SK-(220-414). We conclude that the HPlg that binds to the COOH-terminal domains of SK functions as an enzyme to catalyze the conversion of substrate HPlg that binds to the NH2-terminal domain of SK to human plasmin.

Functional MR to localize sustained visual attention activation in patients with attention deficit hyperactivity disorder: a pilot study

PURPOSE

To evaluate brain control activation in patients with attention deficit hyperactivity disorder (ADHD) and to provide an initial comparison between activated regions in ADHD subjects and those previously localized in an unaffected population.

METHODS

Ten patients with ADHD underwent imaging with a functional blood oxygen level-dependent MR technique during sustained visual vigilance. Pixel activation was inspected visually and statistical group analysis was performed.

RESULTS

Activation was seen over the bilateral middle frontal gyri, the superior parietal lobules, and the inferior parietal lobules. The predominant activity occurred in the right middle frontal gyrus. Application of an additional statistical constraint revealed significant activity in the right inferior and left superior parietal lobules.

CONCLUSION

ADHD patients effectively tolerated the necessary MR imaging constraints despite their difficulty with confinement and immobility. Single-section functional MR imaging revealed activation in brain regions known to be involved in the maintenance of the attention in healthy subjects responding to auditory, tactile, or visual stimulation; additional areas of activity that were identified may represent true abnormal regions in the affected population or artifacts.

Isolation of six low molecular weight heat shock proteins and partial characterization of heat shock protein 29 from mung bean hypocotyl

Heat shock protein (HSP29) together with five other low-M(r) HSPs have been isolated from mung bean hypocotyls by preparative continuous elution SDS-PAGE. Autoradiography and immunochemical analysis of 2D electrophoretograms of the radiolabelled HSP29 revealed that it consists of seven isotypes, two of which are constitutive while the other five are heat-inducible. The pI values of the seven isotypes range from 4.6 to 6.6. A monoclonal antibody raised against the HSP29 isolate reacted with six of the seven isotypes. When HSP29 was subjected to partial proteolysis by V8 Staphylococcus aureus protease (EC 3.4.21.19), two fragments of 12 and 17 kDa were identified, neither of which was recognized by the antibody.

Inadequacy of motion correction algorithms in functional MRI: role of susceptibility-induced artifacts

Functional MR (fMR) has been useful in providing insight into the localization and detection of neural cortical activity. However, patient head motion is inevitable over the course of most fMR experiments. Although methods to align the control and activation fMR images may correct for some of this motional error, they will be incomplete in correcting for those that depend on spatial orientation. MR signal amplitude of structures that lie along air-tissue interfaces, for example, are sensitive to susceptibility errors introduced by their reorientation with respect to the main magnetic field. This analysis, using phantoms, cadaver brain, and volunteers, has shown that this reorientation between control and activation images can create regions of "false activation" that increase in area with rotation. Anatomic regions that are expected to be most affected by these susceptibility-induced magnetic field homogeneity variations are those adjacent to bone or air, such as the mesial and inferior temporal lobes and the inferior and anterior frontal lobes. Interpretation of "activation" in these areas on fMR studies must be performed with careful consideration of this important source of error.

Application of keyhole imaging to interventional MRI: a simulation study to predict sequence requirements

A wide variety of techniques have been proposed recently to improve the temporal resolution of MRI. These include echo-planar imaging methods, wavelet encoding, singular value decomposition encoding, and k-space sharing methods known as "keyhole" imaging. In this work, we use a simulation study to investigate the phase-encoding ordering and data-sharing methods required for the application of keyhole imaging to interventional MRI (I-MRI). The advantages of keyhole imaging over other methods are its simplicity and the use of conventional phase encoding and Fourier transform reconstruction found on virtually all modern MR imagers. Our analysis has predicted that conventional keyhole methods that repeatedly acquire only the center portion of k space, and those that sequentially progress from the center of k space outward, will not meet the combination of temporal and spatial resolution required for tip localization during I-MRI needle insertion. Instead, acquisitions that acquire both high and low k-space data, in ranked order, should provide acceptable tip position and needle width accuracy in both temporal and spatial domains for use in I-MRI.

A simulation study to assess SVD encoding for interventional MRI: effect of object rotation and needle insertion

Singular value decomposition (SVD) encoding offers great promise to provide high spatial and temporal resolution required for interventional MRI (I-MRI) (1). This study investigates its efficacy when (a) objects are rotated and (b) a small device (ie, a needle) is moved within anatomic structures. It was found that SVD-encoded MRI is biased toward the reference from which encoding vectors are derived, thus providing a potential limitation under conditions in which the object has undergone significant global change. Reference images with partial device insertion may be needed to accurately resolve the device or track the object motion. Theoretically, the differences between the reference and the object being imaged suggest that SVD encoding is suboptimal (in a minimum mean squared error sense). Other encoding/reconstruction algorithms may come closer to achieving the desired advantages in spatial and temporal fidelity.

Function of streptokinase fragments in plasminogen activation

Several peptide fragments of streptokinase (SK) were prepared by incubating SK with immobilized human plasmin (hPlm) and purified by h.p.l.c. with a reverse-phase phenyl column. The N-terminal sequences, amino acid compositions and molecular masses of these peptide fragments were determined. The SK peptide fragment of 36 kDa consisting of Ser60-Lys387 (SK-p), was the only peptide fragment that could be tightly bound to immobilized hPlm. Another three large SK peptide fragments, SK-m, SK-n and SK-o, with molecular masses of 7 kDa, 18 kDa and 30 kDa, and consisting of Ile1-Lys59, Glu148-Lys333, Ser60-Lys333 respectively, were also obtained from the supernatant of the reaction mixture. The purified SK-p had high affinity with hPlm and could activate human plasminogen (hPlg) with a kPlg one-sixth that of the native SK. SK-o had low affinity with hPlm and could also activate hPlg, although the catalytic constant was less than 1% of the native SK. SK-n, as well as SK-m, which is the N-terminal 59 amino acid peptide of the native SK, had no activator activity. However, SK-m could enhance the activator activity of both SK-o and SK-p and increase their second-order rate constants by two- and six-fold respectively. It was concluded from these studies that (1) SK-o, the Ser60-Lys333 peptide of SK, was essential for minimal SK activator activity, (2) the C-terminal peptide of SK-p, Ala334-Lys387, was essential for high affinity with hPlm, and (3) the N-terminal 59-amino-acid peptide was important in maintaining the proper conformation of SK to have its full activator activity.

A review of the safety profile of cefixime

Data are reviewed for safety from worldwide clinical trials of 4000 patients and postmarketing studies of 38,000 patients treated with cefixime, a broad-spectrum, bactericidal, beta-lactam stable, third-generation cephalosporin. Adverse experiences were similar in adults and children in all groups, with the most frequent side effects being gastrointestinal in nature. The reported frequency of gastrointestinal adverse experiences was higher in patients in US clinical trials when compared with French, German, or Canadian clinical trials or Canadian or US postmarketing studies. The overall incidence of side effects ranged from 2.7% to 48.2%, and the incidence of gastrointestinal events reported in these studies ranged from 1.4% to 38.6%. Patients infrequently discontinued treatment due to adverse events. The design and methods of data collection in US clinical trials may have resulted in higher frequencies of adverse experiences being reported in US trials when compared with the experiences reported in postmarketing studies and in clinical trials conducted outside of the United States. This is because of the more rigorous methodology used to elicit patient reporting of adverse events in US clinical trials compared with the methodology in postmarketing studies and foreign clinical trials.

Interaction of immobilized human plasminogen and plasmin with streptokinase

The complex of immobilized human plasminogen (iHPlg) and streptokinase (SK) has a lower catalytic activity in hydrolysis of plasmin-specific substrate S-2251 with a kcat/Km of 0.005 microM-1 x s-1, compared to 0.031 microM-1 x s-1 of immobilized human plasmin (iHPlm) and 0.078 microM-1 x s-1 of HPlm. The SK in the complex could be removed by acid buffer solution, and the iHPlg will remain catalytically active. IHPlm.SK complex could activate bovine plasminogen (BPlg), whereas iHPlg.SK complex could not. IHPlg could be activated by interaction with a combination of SK and HPlg or urokinase. The activated iHPlg.SK complex had the ability to activate BPlg as iHPlm.SK. The reasonable explanation is that iHPlg was converted to iHPlm in reaction with the combination of HPlg and SK. However, iHPlg was converted to a virgin enzyme in reaction with SK alone and could not activate BPlg. A new modified mechanism for the interaction of HPlg or HPlm with SK was proposed.

The binding of plasminogen fragments to cultured human umbilical vein endothelial cells

Glu-plasminogen, kringle 1-5, kringle 1-3, and miniplasminogen exhibited strong binding to human umbilical vein endothelial cells (HUVEC). On the other hand, no significant binding was obtained with microplasminogen and kringle 4. Kringle 1-5 and miniplasminogen, which both contained kringle 5, specifically inhibited the binding of plasminogen to HUVEC while kringle 1-3 did not. The results implied plasminogen molecule contained at least two binding sites, with which it interacted HUVEC. The stronger binding site was located in kringle 5 and the weaker one was in kringle 1-3. Kringle 4 and the active site domain exhibited no significant binding to HUVEC. The interaction of plasminogen with HUVEC is mainly through binding site on kringle 5.

Kringle domains and plasmin denaturation

The rate of plasmin denaturation was in the order of Lys-plasmin greater than miniplasmin greater than microplasmin. Fibrinogen degradation products (FDP) dose dependently increased the denaturation rate of Lys-plasmin and mini-plasmin with a maximal rate constant at the FDP/plasmin ratio of about 0.5. The denaturation rate constant of microplasmin was not affected. FDP increased the rate of plasmin denaturation was in parallel with its effect on the interaction among kringle domains. Without FDP only trace amounts of plasminogen dimer could be detected by cross-linking with bis-(sulfo-succinimidyl)-suberate followed by SDS gel electrophoresis. In the low concentration of FDP significant amounts of oligomers of Glu-, mini-plasminogens, kringle 1-3 and kringle 1-5 were observed. High concentration of FDP, however, decreased plasminogen oligomer.

Efficacy and tolerability of cefixime in otitis media. A multicentre study in over 25,000 children

A large scale multicentre clinical study was undertaken to assess the efficacy and tolerability of cefixime in the treatment of acute otitis media in children. A total of 25,863 evaluable children with acute otitis media received cefixime 8 mg/kg once daily for at least 10 days. At the end of treatment, 86% of patients were considered to be either cured or improved. These results are consistent with those achieved with cefixime in controlled clinical trials. Adverse effects were reported in 11.5% of patients, but were judged to be related to cefixime therapy in only 9.4% of patients. The results of this study demonstrate that cefixime is an effective and well tolerated treatment for acute otitis media in children.

Interaction of plasminogen and fibrin in plasminogen activation

Glu1-, Lys77-, miniplasminogens, kringle 1-3, kringle 1-5A, and kringle 1-5R were able to bind with fibrin, while microplasminogen and kringle 4 did not bind significantly. Kringle 1-5A, but not kringle 1-3, effectively inhibited the binding of Glu1-, Lys77-, and miniplasminogens with fibrin. Miniplasminogen also inhibited the binding of Glu1-plasminogen with fibrin. The binding of kringle 1-3 with fibrin was blocked by mini- or Glu1-plasminogen. It is therefore evident that there are two fibrin-binding domains in plasminogen and that the one in kringle 5 is of higher affinity than that in kringle 1-3. CNBr cleavage products of fibrinogen effectively enhanced the activation of Glu1-, Lys77-, or miniplasminogens, but not microplasminogen, by tissue-type plasminogen activator. Kringle 1-5, but not kringle 1-3, dose-dependently inhibited the enhancement by fibrinogen degradation products of Glu1-plasminogen activation by the activator. Lysine and epsilon-aminocaproic acid could inhibit the binding of plasminogens and plasminogen derivatives with fibrin and block the enhancement effect of fibrinogen degradation products on plasminogen activation. The data clearly illustrate that the binding of plasminogen with fibrin, mainly determined by kringle 5, is essential for effective activation by tissue-type plasminogen activator. However, the presence of kringle 1-4 in the plasminogen molecule is required for the full enhancing effect since the kcat/Km of miniplasminogen activation in the presence of fibrinogen degradation products was 8.2 microM-1 min-1 which is significantly less than 52.0 microM-1 min-1 of Glu1-plasminogen.

Activation of human and bovine plasminogens by the microplasmin and streptokinase complex

Human microplasmin is a catalytically active fragment of human plasmin. It consists of a 31-residue C-terminal peptide derived from the A chain bound through two disulfide bonds to the intact B chain of plasmin. It has similar amidolytic and proteolytic activities as the native human Lys-plasmin on a molar basis. Human microplasmin can form a complex with streptokinase, in a one to one stoichiometry, like the native human Lys-plasmin. The stoichiometric human microplasmin and streptokinase complex is an efficient activator of bovine plasminogen which can not be activated by streptokinase alone. The formation of human microplasmin.streptokinase complex was also directly demonstrated by a gel filtration column chromatography. Moreover, bovine plasminogen can not be activated by a mixture of bovine or porcine microplasmin and streptokinase. The equimolar complex of human microplasmin.streptokinase, human Lys-plasmin.streptokinase, or streptokinase alone has the same activator activity toward human Lys-plasminogen. The human microplasmin.streptokinase complex, however, has a significantly higher activator activity than human Lys-plasmin.streptokinase complex or streptokinase alone toward human Glu-plasminogen. The direct interaction between streptokinase and light chain domain of human plasmin is demonstrated in the complex formation. The difference in the activator activities of plasmins from various animal sources in complex with streptokinase therefore might be due to the difference in the compositions of light chains of plasmins.

Transcriptional regulation of the bovine CYP17 (P-450(17)alpha) gene. Identification of two cAMP regulatory regions lacking the consensus cAMP-responsive element (CRE)

Regions within the 5'-flanking sequence of the bovine CYP17 (P-450(17)alpha) gene which are required for cAMP-dependent regulation of transcription have been localized by transient transfection of chimeric reporter gene constructs into mouse adrenal tumor Y1 cells. Two sequences have been found which individually confer cAMP responsiveness to reporter genes; they are located at -243/-225 and -80/-40 base pairs (bp). Obvious sequence homology between these two regions is not apparent. Gel shift competition analysis indicates that nuclear protein(s) binding to the -243/-225-bp region can be competed for by the addition of a double-stranded oligonucleotide containing a consensus cAMP-responsive element (CRE) from the human chorionic gonadotropin alpha gene, whereas addition of this CRE does not abolish protein-DNA complexes formed with fragments containing the -80/-40-bp sequence. Gel shift and Southwestern analysis indicate that the -243/-225-bp region of the P-450(17)alpha gene and the CRE both bind a 47-kDa protein and that the CRE binds additional proteins (43 and 68 kDa) not apparently recognized by the -243/-225-bp sequence. Thus cAMP-dependent regulation of the bovine P-450(17)alpha gene appears to involve two independent cis-regulatory regions, neither of which contains a consensus CRE. Based on protein binding analysis, one of these regions (that including -80/-40 bp) is distinct from the consensus CRE while the other (that containing -243/-225 bp) may be related to the consensus CRE.