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Biological efficacy of L-lysine preparations containing biomass compared to L-lysine-HCl.

In two growth experiments on broilers of 6 to 27 days of age, the biological efficacy of three L-lysine preparations containing biomass was evaluated in comparison to L-lysine.HCl. L-lysine from the different sources was added in graded levels to a basal diet deficient in lysine, but adequate in all other nutrients. From multi-exponential regression analysis of weight gain and feed conversion responses, biological efficacy of the three L-lysine preparations containing biomass was estimated to be 97%, 103%, and 113%, respectively. None of these estimates was significantly different from 100%. Thus, it is concluded that the efficacy of the L-lysine preparations to deliver lysine is equivalent to L-lysine.HCl.

Animal Feed↗

Systemic and fetal-maternal nitric oxide synthesis in normal pregnancy and pre-eclampsia.

OBJECTIVE: To investigate systemic and fetal-placental nitric oxide synthesis by biochemical and molecular biology means in normal human pregnancy and pre-eclampsia. DESIGN AND PARTICIPANTS: Three groups of women were studied: healthy pregnant women (n = 8), pregnant women with pre-eclampsia (n = 8), and age-matched nonpregnant controls (n = 8). Pre-eclamptic patients were treated with nifedipine (30-60 mg/day) for severe hypertension. Systemic nitric oxide synthesis was assessed in normal pregnant women at weeks 18-21, 29-32 and 38-39 and in pre-eclamptic women on admission to the hospital (29-32 weeks, 30 on average), before the morning nifedipine administration. Nonpregnant women were studied twice at four-week intervals as controls. The pattern of nitric oxide biosynthesis in fetal-placental circulation was studied in normal and pre-eclamptic women at the delivery. SETTING: Mario Negri Institute for Pharmacological Research, Bergamo, and the Division of Obstetrics and Gynaecology of the University of Brescia. MAIN OUTCOME MEASURES: Plasma cGMP levels and platelet nitric oxide synthesis, assessed by measuring the conversion of [3H]L-arginine to [3H]L-citrulline as well as intracellular cGMP, were evaluated. Constitutive nitric oxide synthase (EC-NOS) gene expression by Northern blot analysis and nitric oxide release by the conversion of [3H]L-arginine to [3H]L-citrulline were assessed in umbilical vein endothelial cells (HUVEC) and in placenta. Inducible nitric oxide synthase activity was also evaluated in HUVEC exposed to tumour necrosis factor alpha (TNF alpha) and in placenta homogenates incubated in calcium free medium. RESULTS: Plasma cGMP was higher in both normal pregnant and pre-eclamptic women than in nonpregnant controls. In normal pregnancy cGMP rose as early as 18-21 weeks and remained elevated throughout pregnancy. [3H]L-citrulline production and intracellular cGMP were comparable in platelets from all women. EC-NOS gene expression and nitric oxide synthesis were identical in HUVEC and placenta from normal pregnant and pre-eclamptic women. CONCLUSIONS: Systemic levels of CGMP, the nitric oxide second messenger, are increased in normal pregnancy. Excessive nitric oxide production does not derive from platelets. Pre-eclampsia is not associated with changes in fetal-placental nitric oxide synthesis.

Adult↗

Degree of conversion of composites measured by DTA and FTIR.

OBJECTIVE: Differential thermal analysis (DTA) using a split fiber optic light source has been reported to be a convenient method of measuring the degree of conversion (DC) of light-activated composites. The purpose of this study was to compare the results by DTA and Fourier transformation infrared spectroscopy (FTIR), and evaluate the usefulness of the DTA method. METHODS: Experimental 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane-based composites containing SiO2 filler and various amounts of triethyleneglycol dimethacrylate (TEGDMA) were prepared, and the DC of each composite was determined by DTA or FTIR with 60s irradiation. The DC of three proprietary composites containing hybrid filler or prepolymerized resin filler were also measured by both methods with 20 or 60s irradiation. The results were analyzed by ANOVA and Fisher's protected least significant difference test. RESULTS: By both DTA and FTIR, the DC of experimental composites increased as the proportion of TEGDMA increased, although DTA showed 3-10% greater values (p<0.05) than FTIR. For proprietary composites that contain hybrid filler, the values by DTA were not significantly different from those by FTIR at 20s exposure. Longer irradiation time resulted in greater DC (p<0.05) for both methods, and DTA showed 5-7% greater values than FTIR. However, the DC of the composite containing prepolymerized resin filler was 30% less by FTIR than by DTA, possibly due to the influence of unpolymerized species in the filler. SIGNIFICANCE: The DC values determined by DTA and FTIR showed good agreement for most materials including model composites. In addition, DTA may be more useful than FTIR to measure the DC of composites containing prepolymerized resin filler.

Analysis of Variance↗

Identification of the Sin3-binding site in Ume6 defines a two-step process for conversion of Ume6 from a transcriptional repressor to an activator in yeast.

The DNA-binding protein Ume6 is required for both repression and activation of meiosis-specific genes, through interaction with the Sin3 corepressor and Rpd3 histone deacetylase and the meiotic activator Ime1. Here we show that fusion of a heterologous activation domain to Ume6 is unable to convert it into a constitutive activator of early meiotic gene transcription, indicating that an additional function is needed to overcome repression at these promoters. Mutations in UME6 allowing the fusion to activate lie in a predicted amphipathic alpha helix and specifically disrupt interaction with Sin3 but not with Teal, an activator of Ty transcription also found to interact with Ume6 in a two-hybrid screen. The mutations cause a loss of repression by Ume6 and precisely identify the Ume6 Sin3-binding domain, which we show interacts with the paired amphipathic helix 2 region of Sin3. Analysis of these mutants indicates that conversion of Ume6 to an activator involves two genetically distinct steps that act to relieve Sin3-mediated repression and provide an activation domain to Ume6. The mutants further demonstrate that premature expression and lack of subsequent rerepression of Ume6-Sin3-regulated genes are not deleterious to meiotic progression and suggest that the essential role of Sin3 in meiosis is independent of Ume6. The model for Ume6 function arising from these studies indicates that Ume6 is similar in many respects to metazoan regulators that utilize Sin3, such as the Myc-Mad-Max system and nuclear hormone receptors, and provides new insights into the control of transcriptional repression and activation by the Ume6-URS1 regulatory complex in yeast.

Amino Acid Sequence↗

Mucoid-to-nonmucoid conversion in alginate-producing Pseudomonas aeruginosa often results from spontaneous mutations in algT, encoding a putative alternate sigma factor, and shows evidence for autoregulation.

The mucoid phenotype is common among strains of Pseudomonas aeruginosa that cause chronic pulmonary infections in patients with cystic fibrosis and is due to overproduction of an exopolysaccharide called alginate. However, the mucoid phenotype is unstable in vitro, especially when the cells are incubated under low oxygen tension. Spontaneous conversion to the nonmucoid form is typically due to mutations (previously called algS) that are closely linked to the alginate regulatory gene algT, located at 68 min on the chromosome. Our sequence analysis of algT showed that its 22-kDa gene product shares homology with several alternate sigma factors in bacteria, suggesting that AlgT (also known as AlgU) interacts directly with RNA polymerase core to activate the promoters of alginate genes. AlgT showed striking sequence similarity (79%) to sigma E of Escherichia coli, an alternate sigma factor involved in high-temperature gene expression. Our analysis of the molecular basis for spontaneous conversion from mucoid to nonmucoid, in the cystic fibrosis isolate FRD, revealed that nonmucoid conversion was often due to one of two distinct missense mutations in algT that occurred at codons 18 and 29. RNase protection assays showed that spontaneous nonmucoid strains with the algT18 and algT29 alleles have a four- to fivefold reduction in the accumulation of algT transcripts compared with the wild-type mucoid strain. Likewise, a plasmid-borne algT-cat transcriptional fusion was about 3-fold less active in the algT18 and algT29 backgrounds compared with the mucoid wild-type strain, and it was 20-fold less active in an algT::Tn501 background. These data indicate that algT is autoregulated. The spontaneous algT missense alleles also caused about fivefold-reduced expression of the adjacent negative regulator, algN (also known as mucB). Transcripts of algN were essentially absent in the algT::Tn501 strain. Thus, algT regulates the algTN cluster, and the two genes may be cotranscribed. A primer extension analysis showed that algT transcription starts 54 bp upstream of the start of translation. Although the algT promoter showed little similarity to promoters recognized by the vegetative sigma factor, it was similar to the algR promoter. This finding suggests that AlgT may function as a sigma factor to activate its own promoter and those of other alginate genes. The primer extension analysis also showed that algT transcripts were readily detectable in the typical nonmucoid strain PAO1, which was in contrast to a weak signal seen in the algT18 mutant of FRD. A plasmid-borne algT gene in PAO1 resulted in both the mucoid phenotype and high levels of algT transcripts, further supporting the hypothesis that AlgT controls its own gene expression and expression of genes of the alginate regulon.

Alginates↗

Procedures to increase social interaction among adolescents with autism: a multiple baseline analysis.

Isolate behavior, impaired social relationships and lack of conversational skills are behaviors which characterize persons described as autistic. These deficits interfere with their effective integration into school and social environments. This study of three subjects investigates the use of imagery procedures, specifically, covert reinforcement, to increase peer verbal initiations in adolescents who are labeled "autistic" and concomitantly looks at the demand characteristics of therapist "request". A multiple baseline analysis was used to assess the effects of individual training sessions on peer verbal initiations. The results demonstrate that verbal initiations can be changed in socially deficient adolescents labeled "autistic".

Adolescent↗

A medical imaging and visualization toolkit in Java.

Medical imaging research and clinical applications usually require combination and integration of various techniques ranging from image processing and analysis to realistic visualization to user-friendly interaction. Researchers with different backgrounds coming from diverse areas have been using numerous types of hardware, software, and environments to obtain their results. We also observe that students often build their tools from scratch resulting in redundant work. A generic and flexible medical imaging and visualization toolkit would be helpful in medical research and educational institutes to reduce redundant development work and hence increase research efficiency. This paper presents our experience in developing a Medical Imaging and Visualization Toolkit (BIL-kit) that is a set of comprehensive libraries as well as a number of interactive tools. The BIL-kit covers a wide range of fundamental functions from image conversion and transformation, image segmentation, and analysis to geometric model generation and manipulation, all the way up to 3D visualization and interactive simulation. The toolkit design and implementation emphasize the reusability and flexibility. BIL-kit is implemented in the Java language so that it works in hybrid and dynamic research and educational environments. This also allows the toolkit to extend its usage for the development of Web-based applications. Several BIL-kit-based tools and applications are presented including image converter, image processor, general anatomy model simulator, vascular modeling environment, and volume viewer. BIL-kit is a suitable platform for researchers and students to develop visualization and simulation prototypes, and it can also be used for the development of clinical applications.

Algorithms↗

Predictors of success in the conversion of new-onset atrial fibrillation using oral propafenone.

We have investigated the relationship of clinical variables to successful cardioversion of atrial fibrillation (AF) to sinus rhythm using an oral loading dose of propafenone. Fifty consecutive patients with recent onset (< 72 hours) atrial fibrillation of various aetiologies were included in the study cohort. All patients were given the study medication while in the emergency department and then monitored for 8 hours. All patients converting to sinus rhythm (39 out of 50, 78%) were discharged and re-evaluated at 24 hours and 30 days. We investigated the effect of clinical factors such as age, sex, presence of hypertension (HT), chronic obstructive lung disease (COPD), diabetes mellitus (DM), mitral stenosis (MS), congestive heart failure (CHF), coronary artery disease (CAD) and the duration of atrial fibrillation on conversion to sinus rhythm. Of these factors, univariate and multivariate analysis showed that only the duration of atrial fibrillation was a significant predictor of conversion (p = 0.002). Our results suggest that most patients with new-onset AF can be converted successfully to sinus rhythm with a low incidence of adverse reactions using oral propafenone in the emergency department.

Acute Disease↗

[Conversion laparatomies during cholecystectomies under laparoscopy. Apropos of 285 consecutive cholecystectomies].

Retrospective analysis of a consecutive series of 285 cholecystectomies carried out by laparoscopy showed that 47 patients (17.5%) required conversion laparotomy. In 55% of these cases the conversion was due to difficulty in dissecting the gallbladder or cystic duct. Peri-operative cholangiography should be performed routinely, not only to verify the vacuity of the common bile duct (13% of the conversions) but, more particularly, to ensure the integrity of the principal biliary pathway during the dissection (8.5% of the conversions). Cholecystectomy under celioscopy is a proven and safe technique, on the condition that all stages of classical surgery can be carried out under good conditions.

Adolescent↗

Analysis of biofluids for gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) by headspace GC-FID and GC-MS.

The past few years have seen a dramatic increase in the abuse of gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) in the United States. The abuse stems primarily from their euphoric and sedative properties, but these substances are also misused by bodybuilders as steroid alternatives. Recently there has been an alarming increase in the use of GHB and GBL in crimes of drug-facilitated sexual assault. A rapid and sensitive procedure was developed for the analysis of biofluids containing GHB and GBL. Two separate aliquots of a biological specimen were spiked with an alpha-methylene-gamma-butyrolactone internal standard solution. One of the aliquots was treated with concentrated sulfuric acid for cyclization of GHB to GBL and the other remained untreated. Both aliquots were extracted with methylene chloride and concentrated. Extracts were screened using automated headspace gas chromatography-flame-ionization detection (GC-FID). Qualitative findings were quantitated and confirmed in a manner similar to the GC-FID procedure with some modifications. A calibrated solution of GHB-d6 (or GBL-d6, when warranted) was added to the aliquots at a concentration approximating the level determined by the GC-FID screen. The extraction was as described with conversion of GHB to GBL, but analysis was by full-scan gas chromatography-mass spectrometry (El). Quantitation was performed by comparison of the area of the molecular ion of the parent drug (m/z 86) to that of the calibrated deuterated analogue (m/z 92). This analytical procedure allows for the rapid detection of GHB and GBL in biofluids. Its sensitivity has proven useful for the toxicological investigation of cases of drug-facilitated sexual assault.

4-Butyrolactone↗

Oestrogen control of the sexual dimorphism in the Harderian gland of Xenopus laevis.

Xenopus laevis shows a sexual dimorphism of the electrophoretic pattern of Harderian gland (HG) proteins. The male pattern displays three protein fractions whose molecular sizes are approx. 205, 180 and 78 kDa, respectively, and which are absent in the female pattern. Conversely, the female pattern displays two protein fractions of approx. 190 and 76 kDa, respectively. This sexual dimorphism led us to hypothesize a sex steroid control of the HG. Administration of 17beta-oestradiol to male Xenopus converts the male protein pattern into the female one, while the administration of testosterone to the female has no effect. In this respect neither Northern analysis nor the RNase-protection assay performed using a 213 bp encoding for the androgen-binding domain reveals the presence of an androgen receptor mRNA in Xenopus HG. Conversely, Northern analysis has shown an oestrogen receptor mRNA whose size is approx. 6.5 kb and the RNase-protection assay performed by using a 197 bp encoding for the oestrogen-binding domain has also displayed the presence of an oestrogen receptor mRNA in the female HG but not in the male one. In addition, the oestrogen administration to male Xenopus induces the appearance of an oestrogen receptor mRNA. Androgen administration to female toad is ineffective. Taken together, all these findings suggest that in Xenopus laevis oestrogens are involved into the HG physiology. The appearance of an oestrogen receptor mRNA in the oestradiol treated males supports the hypothesis of the occurrence of autoinduction of oestrogen receptor mRNA expression in the HG.

Animals↗

Anesthetic-dependent pial arteriolar response to ethanol.

Anesthetic agents are often administered in the presence of ethyl alcohol, both in research and in the clinical setting. The authors tested the hypothesis that anesthetic agents may affect cerebrovascular responses to ethanol. A closed cranial window preparation in the rat was used to compare the response of pial arterioles to topically applied ethanol (0.01% to 1% vol/vol) in the presence of alpha-chloralose/urethane (50 and 600 mg/kg, respectively) or halothane (0.5% to 1%) anesthesia. Heart rate, mean arterial blood pressure, and blood gas levels were maintained stable and within the physiological range throughout each experiment. Ethanol induced significant vasoconstriction in alpha-chloralose/urethane-anesthetized animals (multivariate analysis of variance (MANOVA), p = 0.039); conversely, ethanol induced significant vasodilation of the pial arterioles in halothane-anesthetized animals (MANOVA, p = 0.017). These responses were significantly different from one another (MANOVA, p = 0.001). Thus, the choice of anesthetic agent alters the cerebrovascular response to ethanol, and care should be taken to ascertain the influence of anesthesia in both research and clinical settings.

Anesthetics↗

Dexamethasone accelerates catabolism of leukotriene C4 in bronchial epithelial cells.

Leukotriene (LT)C4, a potent chemical mediator in bronchial asthma, is metabolised to the less active LTE4 via LTD4 in two consecutive reactions catalysed by enzymes of the glutamyl transpeptidase and dipeptidase families. The activities of these catabolic enzymes may be influenced by glucocorticosteroids. This study was conducted to examine whether this inactivation of LTC4 is affected by dexamethasone (DEX) in transformed human bronchial epithelial cells and normal human bronchial epithelial cells. After incubation with DEX for 0-5 days, cells were resuspended in the presence of exogenous LTC4, and conversion of LTC4 to LTE4 was measured using high-performance liquid chromatography. Gamma-glutamyl transpeptidase (GGT) and GGT-related enzyme (GGTRE) messenger ribonucleic acid (mRNA) expression were examined using reverse transcriptase-polymerase chain reaction analysis, and GGT activity by enzyme assay. Conversion to LTE4 was accelerated by DEX pretreatment. GGTRE but not GGT mRNA expression was enhanced after incubation with DEX. The results indicate that dexamethasone transcriptionally upregulates the activity of gamma-glutamyl transpeptidase-related enzyme in human bronchial epithelial cells, which accelerates inactivation of leukotriene C4 via conversion to leukotriene E4. This is a novel mechanism of glucocorticosteroids in human bronchial epithelial cells.

Analysis of Variance↗

Fourier transform infrared spectroscopy of the solution-mediated conversion of amorphous calcium phosphate to hydroxyapatite: new correlations between X-ray diffraction and infrared data.

Fourier Transform infrared spectroscopic analysis of maturing, poorly crystalline hydroxyapatite (HA) formed from the conversion of amorphous calcium phosphate (ACP) at constant pH or variable pH show only subtle changes in the v1, v3 phosphate absorption region (900 cm-1-1200 cm-1). This region is of interest because it can be detected by analysis of mineralized tissue sections using FT-IR microscopy. To evaluate the subtle spectral changes occurring during the maturation, second derivatives of the spectra were calculated. HA formed at constant pH showed little or no variation in the second derivative peak positions with bands occurring at 960 cm-1, 985 cm-1, 1030 cm-1, 1055 cm-1, 1075 cm-1, 1096 cm-1, 1116 cm-1, and 1145 cm-1. These bands can be assigned to molecular vibrations of the phosphate (PO4(3-)) moiety in an apatitic/stoichiometric environment of HA. In contrast, during the early stages of maturation of the HA formed at variable pH, second derivative peak positions occurring at 958 cm-1, 985 cm-1, 1020 cm-1, 1038 cm-1, 1112 cm-1, and 1127 cm-1 shifted in position with maturation, indicating that the environment of the phosphate species is changing as the crystals mature. Peaks at 1020 cm-1, 1038 cm-1, 1112 cm-1, and 1127 cm-1 were attributable to nonstoichiometry and/or the presence of acid phosphate-containing species. This concept was supported by the lower Ca:P molar ratios measured by chemical analysis of the synthetic material made at variable pH. Using the second derivative peak positions as initial input parameters, the v1, v3 phosphate region of the synthetic HAs prepared at constant pH were curve fit. X-ray diffraction patterns of these same materials were also curve fit to calculate the changes in crystallinty (size/perfection) in the c-axis 002 reflection as well as the 102, 210, 211, 112, 300, 202, and 301 planes. Linear regression analysis showed that the changes in the percent area of the underlying bands at 982 cm-1, 999 cm-1, 1030 cm-1, 1075 cm-1, 1096 cm-1, 1116 cm-1, and 1145 cm-1 were correlated with changes in crystallinity in one or more of the reflection planes. It is suggested that a combination of second-derivative and curve-fitting analysis of the v1, v3 phosphate contour allows the most reproducible evaluation of these spectra.

Calcium Phosphates↗

Behavioral orientations and peer-contact patterns of relationally aggressive girls.

The present study was designed to assess the behavioral orientations and peer-contact patterns of relationally aggressive girls. Based on teachers' assessments of relational aggression, 16 preschool girls were assigned to either a relationally aggressive group or a nonaggressive group and then observed in a free play setting. Several aspects of their interactive behaviors, e.g., cooperative play and social conversation, and noninteractive behaviors, e.g., solitary play and transition, were observed. Analysis indicated the relationally aggressive group spent more time engaged in social conversation and transition and less time in cooperative play than did the nonaggressive group. Further, findings indicated that the relationally aggressive group spent more time with one particular peer than did the nonaggressive group.

Aggression↗

A combined finite element and modal decomposition method to study the interaction of Lamb modes with micro-defects.

This paper presents a combined finite element and modal decomposition method to study the interaction of Lamb waves with damaged area. The finite element mesh is used to describe the region around the defects. On the contrary to other hybrid models already developed, the interaction between Lamb waves and defects is computed in the temporal domain. Then, the modal decomposition method permits to determine the wave reflected and transmitted by the damaged area. Modal analysis allows also identifying the mode conversions induced by the defects. These numerical results agree with previous finite element results concerning the interaction of Lamb modes with a notch. Experiments, carried out with gauged defects on an aluminum plate, are also compared to numerical predictions to validate the simulation. Compared to classical techniques of simulation, this new method allows us to investigate the interaction of Lamb modes generated at high frequency-thickness product with micro-defects as corrosion pitting.

Computer Simulation↗

Parenthood as talked about in Swedish ante- and postnatal midwifery consultations. A qualitative study of 58 video-recorded consultations.

In order to explore the manner in which parenthood was discussed in midwifery consultations, 58 video-recorded consultations were analysed. A content analysis revealed a variety of topics concerning conversation on parenthood--topics of an intimate nature and discussions from a societal perspective. Parenthood was not of primary importance in visits, which were mostly directed by the midwives. A phenomenological hermeneutic analysis of the meaning of being a mother revealed a complex and difficult situation of being both needed and dependent. The meaning of being a father revealed a struggle between distancing from and closeness to the child. The mate relationship was indicated as important and under strain. The metaphor of the 'spiders web', where the mother is the spider with the child mostly on her back, the father entering the web on her terms, summarizes the understanding. The results from this study could provide a basis for reflection on the status of the topic of parenthood, on the meaning of being a mother and a father disclosed in the consultations, and ultimately on the organization of ante- and postnatal midwifery care.

Adult↗

Digital signal and image processing in echocardiography. The American Society of Echocardiography.

Digital signal and image processing techniques are acquiring an increasingly important role in the generation and analysis of cardiac images. This is particularly true of 2D echocardiography, in which image acquisition, manipulation, and storage within the echocardiograph, as well as quantitative analysis of echocardiographic data by means of "off-line" systems, depend upon digital techniques. The increasing role of computers in echocardiography makes it essential that echocardiographers and technologists understand the basic principles of digital techniques applied to echocardiographic instrumentation and data analysis. In this article, we have discussed digital techniques as applied to image generation (digital scan conversion, preprocessing, and postprocessing) as well as to the analysis of image data (computer-assisted border detection, 3D reconstruction, tissue characterization, and contrast echocardiography); a general introduction to off-line analysis systems was also given. Experience with other cardiac imaging methods indicates that digital techniques will likely play a dominant role in the future of echocardiographic imaging.

Echocardiography↗