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Gene localization and expression of thienamycin cyclase gene in Streptomyces lividans TK24.

Transformants of S. lividans TK24 were obtained by transforming a recombinant plasmid p6BC12 harboring the thienamycin cyclase gene into it. An antibacterial substance could be detected by the conversion of fermentation broth of the Y3 block mutant and the purified Y3 mutant intermediate with a cell-free extract of S. lividans TK24 transformant. Paper chromatographic analysis showed that the conversion product of Y3 fermentation broth with cell-free extract of S. lividans TK24 was thienamycin and an unstable antibacterial substance was a product of Y3 intermediate with cell-free extract of the transformants. This result indicated that the thienamycin cyclase gene was expressed in S. lividans TK24 and complemented the deficiency in the Y3 block mutant. Restriction analysis of p6BC12 was carried out and the restriction map was constructed. The thienamycin cyclase gene was localized on a 0.9 kb PstI-HinCII fragment from a bioconversion result. The 1.0 kb IPNS homologous DNA fragment in plasmid p6BC12 was excluded from the cyclase activity.

Genes, Bacterial↗

Analysis of the rationale for, and consequences of, nonprofit and for-profit ownership conversions.

OBJECTIVES: To examine percursors to private hospitals conversion, both from nonprofit status to for-profit status and from for-profit to nonprofit status, as well as the effect of hospital conversions on hospital profitability, efficiency, staffing, and the probability of closure. DATA SOURCES: The Health Care Financing Administration's Medicare Cost Reports and the American Hospital Association's Annual Survey of Hospitals. STUDY DESIGN: Bivariate and multivariate analyses comparing conversion hospitals to nonconversion hospitals over time were conducted. DATA EXTRACTION METHODS: The study sample consisted of all private acute care hospital conversions that occurred from 1989 through 1992. PRINCIPAL FINDINGS: Hospitals that converted had significantly lower profit margins prior to converting than did nonconversion hospitals. This was particularly true for nonprofit to for-profit conversions. After converting, both nonprofit and for-profit hospitals significantly improved their profitability. Nonprofit to for-profit hospital conversions were associated with a decrease in the ratio of staff to patients. No association was found between for-profit to nonprofit conversion and staff-to-patient ratios. The difference seems partially attributed to the fact that nonprofit hospitals that converted had higher staff ratios than the industry average. For-profit to nonprofit hospital conversions were associated with an increase in the ratio of registered nurses to patients and administrators to patients, despite the fact that nonprofit and for-profit hospitals did not differ in these ratios. CONCLUSIONS: The improvement in financial performance following hospital conversions may be a benefit to the community that policymakers want to consider when regulating hospital conversions.

Acute Disease↗

Mechanism and kinetics of low-temperature thermochemical conversion process for sewage sludge.

The low-temperature thermo-chemical conversion process for sewage sludge is a prospective technology, through which the energy in the sludge can be recovered. With the help of elementary analysis of sewage sludge and its conversion products, thermal gravimetric analysis (TGA) of the sludge and GC/MS analysis of the derived oil, a study was carried out on element transfer, characteristic conversion temperature and conversion reaction mechanism of the process. The following results are obtained: 1) the predominant conversion reactions are distillation of aliphatic compounds, splitting of protein peptide bonds and group transfer; and 2) the main components involved in the conversion are aliphatic compounds and protein, with the lower reaction temperature for the former, the higher for the latter and the highest for saccharides. Based on the mechanism analyses, the simplified reaction model of the thermo-chemical conversion process for sewage sludge consists of two serial competitive reactions (producing volatile matter and char respectively). The estimated Arrhennius kinetic parameters of the reaction model based on TGA testing resultsare A1 = 4.15 x 10(6) 1/s, n1 = 2, E1 = 98 kJ/mol; A2 = 1.42 x 10(5) 1/s, n2 = 2, E2 = 85 kJ/mol; A3 = 1.01 x 10(12) 1/s, n3 = 4, E3 = 190 kJ/mol; A4 = 1.33 x 10(9) 1/s, n4 = 4, E4 = 146 kJ/mol.

Conservation of Natural Resources↗

Human hypertension caused by mutations in the 11 beta-hydroxysteroid dehydrogenase gene: a molecular analysis of apparent mineralocorticoid excess.

CONVERSION OF CORTISOL TO CORTISONE: 11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD) is a microsomal enzyme complex which, in humans, catalyses the interconversion between biologically active cortisol and inactive cortisone. This prereceptor signalling mechanism is essential for maintaining the aldosterone selectivity of the intrinsically non-specific mineralocorticoid receptor and for modulating glucocorticoid access to the glucocorticoid receptor. Apparent mineralocorticoid excess (AME) is a syndrome of severe low-renin mineralocorticoid hypertension associated with marked hypokalaemia which arises from a congenital deficiency of 11 beta-HSD. In AME patients, therefore, it is cortisol and not aldosterone which behaves as a potent mineralocorticoid. ISOFORMS OF 11 BETA-HSD: Two isoforms of human 11 beta-HSD have now been characterized and cloned. The type 1 isoform (11 beta-HSD1) is a low-affinity reduced nicotinamide adenine dinucleotide phosphate (NADP) dependent dehydrogenase-oxoreductase which is expressed in predominantly glucocorticoid target tissues and the encoding sequence of which is normal in patients with AME. In contrast, the type 2 isoform (11 beta-HSD2) is a high-affinity NADP-dependent unidirectional dehydrogenase which is expressed in placenta and mineralocorticoid target tissues such as renal collecting ducts and distal colonic epithelia. Exon- and intron-specific polymerase chain reaction amplification of the 11 beta-HSD2 gene from genomic DNA from members of a consanguinous kindred with AME consistently revealed a single missense mutation (C1228T) in two affected sibs and twin stillbirths. This mutation in codon 374 of exon 5 of the 11 beta-HSD2 gene creates an inframe premature stop (TGA) and, as such, results in a truncated 11 beta-HSD2 protein lacking the carboxyl-terminal proline-rich 32 amino acids. In keeping with an autosomal recessive mode of inheritance, both parents were phenotypically and biochemically normal but were heterozygous for this mutation. Unique to this kindred were expression analyses of the native mutant 11 beta-HSD2 enzyme in the stillbirth-affected placenta, which was almost completely devoid of NADP-dependent 11 beta-dehydrogenase activity. Immunohistochemical and Western blot analyses revealed the absence of 11 beta-HSD2 protein using antisera raised against synthetic peptide sequences corresponding either to the carboxyl terminus or other domains of the enzyme. MISSENSE MUTATION: In this kindred with AME, congenital deficiency of 11 beta-HSD activity is due to a single missense mutation in exon 5 of the 11 beta-HSD2 gene. Simultaneous studies by two other groups have similarly revealed no gross deletions or rearrangements of the 11 beta-HSD2 gene, but have described a number of single point mutations and oligonucleotide deletions in exons 3, 4 and 5, and adjacent to a splice site in intron 3. Recombinant expression analysis of site-directed mutant 11 beta-HSD2 complementary DNA constructs suggests a correlation between the predicted severity of these mutations and the biochemical and clinical phenotype. AME AS A CAUSE OF HYPERTENSION: The mutations in the 11 beta-HSD2 gene, together with those currently being sought by us for other kindreds with AME, establishes AME as a monogenic cause of human hypertension and will provide insight into the structure-function relationships of this important enzyme.

11-beta-Hydroxysteroid Dehydrogenases↗

Absorbed-dose beam quality conversion factors for cylindrical chambers in high energy photon beams.

Recent working groups of the AAPM [Almond et al., Med. Phys. 26, 1847 (1999)] and the IAEA (Andreo et al., Draft V.7 of "An International Code of Practice for Dosimetry based on Standards of Absorbed Dose to Water," IAEA, 2000) have described guidelines to base reference dosimetry of high energy photon beams on absorbed dose to water standards. In these protocols use is made of the absorbed-dose beam quality conversion factor, kQ which scales an absorbed-dose calibration factor at the reference quality 60Co to a quality Q, and which is calculated based on state-of-the-art ion chamber theory and data. In this paper we present the measurement and analysis of beam quality conversion factors kQ for cylindrical chambers in high-energy photon beams. At least three chambers of six different types were calibrated against the Canadian primary standard for absorbed dose based on a sealed water calorimeter at 60Co [TPR10(20)=0.572, %dd(10)x=58.4], 10 MV [TPR10(20)=0.682, %dd(10)x=69.6), 20 MV (TPR10(20)=0.758, %dd(10)x= 80.5] and 30 MV [TPR10(20) = 0.794, %dd(10)x= 88.4]. The uncertainty on the calorimetric determination of kQ for a single chamber is typically 0.36% and the overall 1sigma uncertainty on a set of chambers of the same type is typically 0.45%. The maximum deviation between a measured kQ and the TG-51 protocol value is 0.8%. The overall rms deviation between measurement and the TG-51 values, based on 20 chambers at the three energies, is 0.41%. When the effect of a 1 mm PMMA waterproofing sleeve is taken into account in the calculations, the maximum deviation is 1.1% and the overall rms deviation between measurement and calculation 0.48%. When the beam is specified using TPR10(20), and measurements are compared with kQ values calculated using the version of TG-21 with corrected formalism and data, differences are up to 1.6% when no sleeve corrections are taken into account. For the NE2571 and the NE2611A chamber types, for which the most literature data are available, using %dd(10)x, all published data show a spread of 0.4% and 0.6%, respectively, over the entire measurement range, compared to spreads of up to 1.1% for both chambers when the kQ values are expressed as a function of TPR10(20). For the PR06-C chamber no clear preference of beam quality specifier could be identified. When comparing the differences of our kQ measurements and calculations with an analysis in terms of air-kerma protocols with the same underlying calculations but expressed in terms of a compound conversion factor CQ, we observe that a system making use of absorbed-dose calibrations and calculated kQ values, is more accurate than a system based on air-kerma calibrations in combination with calculated CQ (rms deviation of 0.48% versus 0.67%, respectively).

Air↗

Application of 13C-NMR spectroscopy to in vitro analysis of enzyme kinetics.

The conversion of D,L-alpha-13C-histidine to similarly labeled alpha-13C histamine by bacterial and mammalian histidine decarboxylase was studied by 13C-NMR spectroscopy and GLC-mass spectrometry. The results obtained with the partially purified bacterial enzyme were in essentially perfect agreement with results obtained simultaneously with a standard radioisotopic method using carboxyl-labeled-14C-L-histidine. For a crude tissue preparation of the mammalian enzyme, the radioisotopic method indicated an activity three times that based on 13C-NMR measurement of alpha-13C-histamine. The difference in results was accountable in terms of additional 13C-NMR signals attributable to products other than histamine due in part to enzymatic degradation of the latter.

Animals↗

A test of conversational and testimonial messages versus didactic presentations of nutrition information.

OBJECTIVE: Conversational and testimonial approaches to presenting messages relevant to fruit and vegetable consumption were compared with a traditional didactic message. DESIGN: A Greco-Latin square, within-subjects experimental design was employed with 3 formats and 3 topics. SETTING: Community centers. PARTICIPANTS: Thirty-one ethnically diverse adults. INTERVENTION: Presented conversational, testimonial, and didactic nutrition messages. VARIABLES MEASURED: Believability, clarity, and perceived usefulness of messages presented; identification with sources in message; and self-efficacy with respect to produce consumption. ANALYSIS: Analysis of variance. RESULTS: Conversational formats were perceived as more believable than the control newsletter article. No differences were found with respect to clarity, usefulness, or self-efficacy. Identification with characters did significantly interact with message format in predicting the message assessment variables. However, the conversation and testimonial versions did not increase identification with persons in the message over the didactic presentation. CONCLUSIONS AND IMPLICATIONS: Audience response to narrative messages is contingent upon identification with persons portrayed in the message. The results underscore the need for careful pretesting of involvement with the story and identification with persons portrayed to maximize the effectiveness of narrative messages in health interventions.

Adult↗

Analysis of divergence of Alphitobius diaperinus satellite DNA--roles of recombination, replication slippage and gene conversion.

Satellite DNA is highly abundant in Alphitobius diaperinus (Tenebrionidae, Coleoptera), comprising 25% of the total genomic DNA. Sequence analysis reveals an average GC content of 50.8% and the presence of three different groups of satellite monomer variants, tH1, tH2 and tH3 with corresponding lengths of 123, 128 and 126 bp. Their mutual homologies range between 65 and 81%. Sequence comparison shows that the monomer variant tH2 has been formed by a recombination process between tH1 and tH3, which have a low average homology of only 65.15%. The longest stretch of 100% homology between the recombining units is 17 bp and is located 3' to the predicted recombination site. There is also an indication from sequence analysis that replication slippage and gene conversion play a part in the formation of satellite units and contribute to their divergence. The tH1, tH2 and tH3 monomer variants are organized in higher order repeating structures: a dimer, composed of tH1 and tH3, and a trimer containing tH1, tH2 and tH3 in series. The dimeric and trimeric repeat units furthermore create three higher order satellite subfamilies. Two of them contain either tandemly arranged dimers or trimers, while the third one is composed of both types of repeats, mutually interspersed.

Animals↗

Laparoscopic cholecystectomy in acute cholecystitis.

BACKGROUND: In the light of laparoscopic cholecystectomy increasingly applied to all forms of cholecystitis, this study aimed at evaluating the safety of laparoscopic cholecystectomy applied to all cases of acute cholecystitis, and at determining factors associated with the risk of conversion to open cholecystectomy. METHODS: The clinical, biochemical, radiologic, and operative data from 124 consecutive cases of acute cholecystitis were analyzed retrospectively to determine the complications and morbidity after operation. The data were analyzed further by univariate and multivariate analysis to identify factors associated with conversion. RESULTS: No major bile duct injury or mortality occurred. Bile leak from the stump of the cystic duct developed in four patients. These were managed successfully by endoscopic biliary stent placement. The mean duration of hospital stay was 3.8 days in the laparoscopic group and 8.2 days in the open group. Of the 124 patients (18.5%), 23 underwent conversion to open cholecystectomy. Univariate analysis identified the following factors as associated with conversion: common duct dilation greater than 7 mm observed on ultrasound, (p < 0.05), pericholecystic collection seen on ultrasound (p < 0.0001), emphysematous cholecystitis (p < 0.01), endoscopic retrograde cholangiopancreatographic evidence of Mirizzi syndrome (p < 0.05), and pericholecystic collection at operation (p < 0.0001). On multivariate analysis, only pericholecystic collection (p < 0.015) and gallbladder wall thickness greater than 5 mm (p < 0.013) were statistically significant. CONCLUSIONS: Laparoscopic cholecystectomy for acute cholecystitis can be applied safely to all comers, offering the advantage of a shortened hospital stay. Pericholecystic collection, as observed on ultrasound, is associated with a high risk of conversion to open cholecystectomy.

Acute Disease↗

Clinical determinants of sinus conversion by radiofrequency maze procedure for persistent atrial fibrillation in patients undergoing concomitant mitral valvular surgery.

The radiofrequency Maze procedure can effectively restore sinus rhythm in most patients with atrial fibrillation (AF) and mitral valve disease. AF after cardiac surgery is associated with increased morbidity and mortality. However, clinical determinants of long-term postoperative AF after the radiofrequency Maze procedure and concomitant mitral valve surgery are poorly defined. This study comprised 99 consecutive patients with persistent AF and mitral valve disease who underwent radiofrequency Maze procedures and concomitant mitral valvular operations. The predictive values of clinical variables for postoperative AF were examined. After a mean follow-up period of 46.1+/-24.6 months, 83 patients (83.8%) had sinus conversion after the Maze procedure, and 16 patients remained in persistent or paroxysmal AF. Multiple logistic regression analysis determined that predictors of sinus conversion were preoperative left atrial diameter (odds ratio [OR] 1.127 per 1-mm increment in left atrial diameter, 95% confidence interval [CI] 1.045 to 1.215, p<0.002) and the duration of AF (OR 1.022 per 1-month increment in duration of AF, 95% CI 1.009 to 1.035, p<0.001). Discriminant analysis showed that the sinus conversion rate was significantly lower in patients with preoperative left atrial diameters>56.8 mm (p<0.001) or AF duration>66 months (p<0.001) than in patients with preoperative left atrial diameters<56.8 mm or AF duration<66 months. In conclusion, the preoperative left atrial size and duration of AF are primary predictors of sinus conversion by the radiofrequency Maze procedure for patients with persistent AF and mitral valve disease.

Adult↗

Relationship between the oncogene activation profiles and the tumor suppressor gene inactivation profiles in 19 human neoplasias - a regression analysis study of the intercancer linkage with the world cancer incidence data.

This study represents an extension of our statistical studies of age-adjusted incidence rates (AAIRs) of 19 neoplasias from 47 population units of the world. We have invented 2 data manipulation methods (topological data conversion and sequential regression analysis method) to estimate separately the intensities of each oncogene activation and tumor suppressor gene inactivation of a given tumor (marker tumor) relative to a counterpart tumor (reference tumor) in terms of r seq value. This study prepared the r seq table of all permutations of tumor pairs for each of the 2 cancer genes and for each sex first, and then investigated the relation between the r seq profile of oncogene activation and that of tumor suppressor gene inactivation for each tumor. A profile containing 16 (male) or 17 (female) r seq data was prepared for each tumor pair, for each cancer gene, and for each sex. The extent of similarity between 2 r seq profiles was assessed by the 1st order regression analysis in terms of the correlation coefficient r value. Results obtained are given as follows: a) The proportions of both the tumor pairs with r seq values of less than -0.90 in the oncogene activation tables of two sexes and those with r seq values of more than +0.90 in the tumor suppressor gene inactivation tables of the two sexes were all more than 50%. A small number of tumor pairs in both the oncogene activation tables and the tumor suppressor gene inactivation tables have invaded deep into each the plus- and the minus-areas to constitute the very end of long tails of the r seq profiles. b) In spite of the above symmetry of data distribution between the 2 cancer-gene tables, individual cancer pairs very rarely gave 2 cancer-gene profiles that fit the definition of symmetry. Taken together, our data manipulation was a success in presenting an oncogene activation profile and a tumor suppressor gene inactivation profile separately. c) The similarity test was conducted with all combinations of tumor pair profiles for each cancer gene and for each sex. The frequency distributions of r values in the oncogene activation tables of both sexes looked normal with long tails to both the plus- and the minus-areas. In contrast, the corresponding frequency distributions of r in the tumor suppressor gene inactivation tables of both sexes were skewed towards the direction of +1.0. It was indicated that the morphological specificity of the oncogene activation profiles was much higher than that of the tumor suppressor gene inactivation profiles. d) Male versus female comparison in 2 neoplasias with sex discrimination of cancer risk revealed that the combination of the general depression of r seq values in the oncogene profile of dominant gender and the general elevation of r seq values in the oncogene profile of recessive gender was the common trait of female-dominant breast cancer and male-dominant laryngeal cancer. It is suggested that the predominance of oncogene activation impact over the tumor suppressor gene inactivation impact was implicated in the creation of sex discrimination of cancer risk. e) Application of a new test method (reciprocal regression analysis) to the r seq table data led to the conclusion that the 2 cancer genes are interfering with each other, and that the balance of power between the 2 cancer genes varies from one marker tumor to the other. f) The results obtained in this study together with the consistency of data interpretation is discussed in light of thermodynamics.

Female↗

Meiotic recombination and flanking marker exchange at the highly unstable human minisatellite CEB1 (D2S90).

Unequal crossover has long been suspected to play a role in the germline-specific instability of tandem-repeat DNA, but little information exists on the dynamics and processes of unequal exchange. We have therefore characterized new length alleles associated with flanking-marker exchange at the highly unstable human minisatellite CEB1, which mutates in the male germline by a complex process often resulting in the gene conversion-like transfer of repeats between alleles. DNA flanking CEB1 is rich in single-nucleotide polymorphisms (SNPs) and shows extensive haplotype diversity, consistent with elevated recombinational activity near the minisatellite. These SNPs were used to recover mutant CEB1 molecules associated with flanking-marker exchange, directly from sperm DNA. Mutants with both proximal and distal flanking-marker exchange were shown to contribute significantly to CEB1 turnover and suggest that the 5' end of the array is very active in meiotic unequal crossover. Coconversions involving the interallelic transfer of repeats plus immediate flanking DNA were also common, were also polarized at the 5' end of CEB1, and appeared to define a conversion gradient extending from the repeat array into adjacent DNA. Whereas many mutants associated with complete exchange resulted in simple recombinant-repeat arrays that show reciprocity, coconversions were highly gain-biased and were, on average, more complex, with allele rearrangements similar to those seen in the bulk of sperm mutants. This suggests distinct recombination-processing pathways producing, on the one hand, simple crossovers in CEB1 and, on the other hand, complex conversions that sometimes extend into flanking DNA.

Alleles↗

Infants' early ability to segment the conversational speech signal predicts later language development: a retrospective analysis.

Two studies examined relationships between infants' early speech processing performance and later language and cognitive outcomes. Study 1 found that performance on speech segmentation tasks before 12 months of age related to expressive vocabulary at 24 months. However, performance on other tasks was not related to 2-year vocabulary. Study 2 assessed linguistic and cognitive skills at 4-6 years of age for children who had participated in segmentation studies as infants. Children who had been able to segment words from fluent speech scored higher on language measures, but not general IQ, as preschoolers. Results suggest that speech segmentation ability is an important prerequisite for successful language development, and they offer potential for developing measures to detect language impairment at an earlier age.

Aptitude↗

Linguistic aspects of speech synthesis.

The conversion of text to speech is seen as an analysis of the input text to obtain a common underlying linguistic description, followed by a synthesis of the output speech waveform from this fundamental specification. Hence, the comprehensive linguistic structure serving as the substrate for an utterance must be discovered by analysis from the text. The pronunciation of individual words in unrestricted text is determined by morphological analysis or letter-to-sound conversion, followed by specification of the word-level stress contour. In addition, many text character strings, such as titles, numbers, and acronyms, are abbreviations for normal words, which must be derived. To further refine these pronunciations and to discover the prosodic structure of the utterance, word part of speech must be computed, followed by a phrase-level parsing. From this structure the prosodic structure of the utterance can be determined, which is needed in order to specify the durational framework and fundamental frequency contour of the utterance. In discourse contexts, several factors such as the specification of new and old information, contrast, and pronominal reference can be used to further modify the prosodic specification. When the prosodic correlates have been computed and the segmental sequence is assembled, a complete input suitable for speech synthesis has been determined. Lastly, multilingual systems utilizing rule frameworks are mentioned, and future directions are characterized.

Communication↗

A conversational program for hierarchic and non-hierarchic cluster analysis.

The theoretical basis and the features of some cluster analysis programs are described in this paper. These programs use as input data an N x M matrix. For the N' less than or equal to N set of individuals, the cross-correlation matrix, R = (rij), is then calculated. The dissimilarity matrix, D = (dhk), and the distribution histogram of the distances between each pair is worked out. Hierarchic and non-hierarchic clustering techniques are allowed. Using the non-hierarchic strategy, the non-overlapping clusters are then separated into different groups. The distances between these groups are calculated and statistical tests of significance are performed. In the hierarchic case, a dendrogram is drawn using an agglomerative algorithm. As an example the programs (written in FORTRAN, batch or TSS version) were used to classify human mitotic chromosomes.

Classification↗