SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
This paper presents a family-therapy technique--time-extended family interviewing--in which the therapist extends the traditional one-hour interview to three to seven hours, by plan, at a particular point in the life of a case and for a particular purpose. Extended sessions promote movement in a case for a variety of reasons. Furthermore, the use of such sessions highlights the dimension of time as an important element of good casework practice.
An extended-spectrum beta-lactamase, the gene for which is located on plasmid pMS350 in Pseudomonas aeruginosa strains, hydrolyzes carbapenems and other extended-spectrum beta-lactam antibiotics. We cloned the pMS350 beta-lactamase gene in an Escherichia coli K-12 strain using the vector plasmid pHSG398, and subcloned it into pMS360, a plasmid with a wide host-range. This resulted in the formation of the recombinant plasmid, pMS363, containing a 4.1-kb DNA insert that includes the extended-spectrum beta-lactamase gene. Plasmid pMS363 was introduced into the P. aeruginosa PAO strain or into six species of Enterobacteriaceae, and the specific activities of the beta-lactamase and MICs of various beta-lactam antibiotics were estimated. The cloned gene was capable of expression in these strains and caused resistance to carbapenem, penem and other beta-lactam antibiotics, with the exception of aztreonam.
A clinical isolate of Pseudomonas aeruginosa, JES, was resistant to extended-spectrum cephalosporins with a marked synergistic effect with clavulanic acid on a routine antibiogram. Preliminary PCR analysis revealed the presence of blaVEB-1, an integron-located gene encoding an extended-spectrum beta-lactamase previously identified in Escherichia coli MG-1. Using class 1 integron primers and blaVEB-1 intragenic primers, the insert region of the blaVEB-1 containing integron along with some flanking sequence from P. aeruginosa JES was amplified and subsequently sequenced. In50 contains within its variable region, in addition to qacE delta 1 and sull genes commonly found in class 1 integrons, two gene cassettes, veb1 and aadB. In50 is peculiar since its attI1 site is interrupted by two novel insertion sequences, IS1999 and IS2000. P. aeruginosa JES and Escherichia coli MG-1 strains were isolated from patients previously hospitalized in south east Asian countries. The finding of blaVEB-1 in these strains and on different integrons underlines the interspecies spread of this integron-located extended-spectrum beta-lactamase gene.
This study evaluated the effects of additional and extended acid etching on microtensile bond strength ( micro TBS) of two adhesive systems to sound (SD) and caries-affected dentine (CAD). Flat surfaces of CAD surrounded by SD of 36 extracted carious third molars were assigned to four treatments (i): self-etching adhesive system (Clearfil SE Bond) applied to dentine surfaces following manufacturer's instructions (MI); (ii) after additional etching for 15 s (35% phosphoric acid, PA); (iii) total-etch one-bottle adhesive (Single Bond) applied to dentine surfaces following MI; or (iv), after etching for 45 s with PA. Composite 'blocks' were built on bonded surfaces and restored teeth were vertically sectioned to obtain bonded slices of 0.7 mm thick. Slices were trimmed to create hourglass-shaped specimens (cross-sectional area of 1 mm(2)), which were tested under tension in a universal testing machine. Additional CAD and SD samples were prepared for scanning electron microscopy observations. Additional and extended etching significantly increased micro TBS to CAD; however, micro TBS of both adhesives to CAD were significantly lower than to SD. Additional and extended etching can improve bonding to CAD; however, adhesives applied on SD showed the best results for bonding.
AIM: To establish a method for cynomolgus monkey sperm cryopreservation in a chemically defined extender. METHODS: Semen samples were collected by electro-ejaculation from four sexually mature male cynomolgus monkeys. The spermatozoa were frozen in straws by liquid nitrogen vapor using egg-yolk-free Tes-Tris mTTE synthetic extender and glycerol as cryoprotectant. The effects of glycerol concentration (1 %, 3 %, 5 %, 10 % and 15 % [v/v]) and its equilibration time (10 min, 30 min, 60 min and 90 min) on post-thaw spermatozoa were examined by sperm motility and sperm head membrane integrity. RESULTS: The post-thaw motility and head membrane integrity of spermatozoa were significantly higher (P0.05) for 5 % glycerol (42.95 +/- 2.55 and 50.39+/- 2.42, respectively) than those of the other groups (1%: 19.19 +/- 3.22 and 24.84 +/- 3.64; 3%: 34.23 +/- 3.43 and 41.37 +/- 3.42; 10%:15.68 +/- 2.36 and 21.39 +/- 3.14; 15%: 7.47 +/- 1.44 and 12.90 +/- 2.18). The parameters for 30 min equilibration(42.95 +/- 2.55 and 50.39 +/- 2.42) were better (P0.05) than those of the other groups (10 min: 31.33 +/- 3.06 and 38.98 +/- 3.31; 60 min: 32.49 +/- 3.86 and 40.01 +/- 4.18; 90 min: 31.16 +/- 3.66 and 38.30 +/- 3.78). Five percent glycerol and 30 min equilibration yielded the highest post-thaw sperm motility and head membrane integrity. CONCLUSION: Cynomolgus monkey spermatozoa can be successfully cryopreserved in a chemically defined extender, which is related to the concentration and the equilibration time of glycerol.
Evolutionary theories suggest that the expression of extended longevity depends on the organism's ability to shift energy from reproduction to somatic maintenance. New data led us to reexamine our older data and integrate the two into a larger picture of the genetic and metabolic alterations required if the animal is to live long. Our Ra normal-lived control strain can express any one of three different extended longevity phenotypes, only one of which involves significant and proportional increases in both mean and maximum longevity and thus a delayed onset of senescence. This phenotype is dependent on the up-regulation of the antioxidant defense system (ADS) genes and enzymes. Animals that express this phenotype typically have a pattern of altered specific activities in metabolically important enzymes, suggesting they are necessary to support the NAD+/NADP+ reducing system required for the continued high ADS enzyme activities. Fecundity data suggests that the energy required for this higher level of somatic maintenance initially came from a reduced egg production. This was only transient, however, for the females significantly increased their fecundity in later generations while still maintaining their longevity. The energy required for this enhanced fecundity was probably obtained from an increased metabolic efficiency, for the mitochondria of the La long-lived strain are metabolically more efficient and have a lower leakage of reactive oxygen species (ROS) to the cytosol. Selection pressures that do not lead to these shifts in energy allocations result in extended longevity phenotypes characterized by increased early survival or increased late survival but not by a delayed onset of senescence.
OBJECTIVES: The study assessed the impact of intergenerational differences of opinion over child rearing on the mental health of Muslim mothers living in extended families. DESIGN: The study adopted a correlational design in an attempt to identify factors that accounted for mental health problems. METHODS: The child-rearing attitudes of mothers and grandmothers, mothers' mental health, levels of family acculturation and a range of other background and demographic information was collected from 54 extended families living in two Muslim communities in London using Urdu versions of standard questionnaires. RESULTS: Rates of depression and anxiety among the mothers in the study were high. Grandmothers had more traditional attitudes to child rearing than did mothers. Intergenerational discrepancy over child rearing was more marked in more acculturated families. Discrepancy was associated with higher levels of mothers' anxiety and depression. CONCLUSIONS: The unusually high levels of depression and anxiety displayed by Muslim mothers living in extended families can in part be accounted for by patterns of intergenerational discrepancy. These possibly reflect discordant world views within those families that have been assimilated into the dominant British culture.
A general methodology is provided for the absolute assay of radioisotopes decaying with coincident photons in an extended source. In the determination of the source activity, the method requires neither the detailed consideration of the geometric and self-attenuation processes taking place between the source component points nor a knowledge of the distribution of activity across the source. It derives from the concept of the "equivalent point source," that is a fictitious point source whose activity would equal that measured for the actual extended source. It has been developed for an arbitrary number of coincident photon types displaying an arbitrary degree of mutual correlation, and for arbitrary detection geometry. A unifying formalism is developed for both point and extended sources and for single and dual detecting systems. It is found that in all cases the various instrumental and spectroscopic uncertainties appear within a composite parameter (herein called F factor) that can be determined by standard calibration procedures; this factor is in turn only weakly dependent on its own component parameters. New expressions and relationships are obtained that provide a greater physical insight into coincidence-counting methods.
Depth dose characteristics of 24-MV beams from a medical linear accelerator at various SSDs have been measured. The dose buildup, percent depth dose (PDD), and output were measured using ionization chambers and a diode detector under full scatter. Surface dose ranged from 8% to 51% depending upon the collimator setting at 100-cm SSD. It decreased by 10%-15% as distance was increased to 200 cm, but remained unchanged beyond this distance. The dmax migrated rapidly toward the surface with increasing field size at 100-cm SSD. At extended SSD, the dmax occurred at greater depths and shifted a little toward the shallow depths with increasing field size. Large field PDDs measured at extended SSD agreed well with those predicted from 100-cm data. The output followed the 1/(distance)2 relationship quite well. The extended SSD beam data are clinically useful when treating hemibody or performing total body irradiation (TBI) procedures.
A uniform dose to the target site is required with a knowledge of delivered dose, central axis depth dose, and beam flatness for successful electron treatment at an extended source to surface distance (SSD). The central axis depth dose is shown to be nearly independent of moderate changes in the treatment distance. The delivered dose at a point could be calculated with the concept of virtual source position and an inverse square correction. In an extended SSD treatment, underdosage of the lateral tissue may occur due to reduced beam flatness. To study the changes in beam characteristics, the depth dose and beam flatness were measured at different SSDs for clinically used field sizes [(3 x 3)-(15 x 15) cm2] and beam energies ranging from 6 to 20 MeV. Our results indicate that the changes in depth dose are minimal except in the buildup region for most energies. In general, the surface dose is decreased (< or = 10%) as the SSD is increased moderately. Beam flatness was measured in terms of target coverage factor (TCF) defined as the ratio of the width of a specified isodose line to the geometrical field width. It was observed that the loss in beam flatness is significant for smaller fields, higher isodose lines, and lower energies. Variations in SSD have a minimal effect on the relative changes in beam flatness for field sizes greater than 8 x 8 cm2. The lateral loss of beam uniformity could be estimated by various parameters, such as the full width at half maximum, the homogeneity index, the uniformity index, and the TCF; however, TCF is a simpler parameter to use clinically. The beam characteristics (depth dose and TCF) at extended treatment distances are presented for electron beams.
This study investigated two sources of variance in the ability to discriminate auditory profiles: individual differences and extended training. The goals of the study were (1) to determine the range and origins of individual differences in profile analysis and (2) to determine whether those who initially had poor sensitivity to changes in spectral shape could eventually acquire finer sensitivity. Profile stimuli had 11 components with equal-log spacing from 200-2200 Hz. Thresholds ranged from - 1 to -25 dB (signal level relative to the context level) across 46 listeners. The correlation between spectral-shape discrimination thresholds after 2000 trials and pure-tone intensity-discrimination thresholds was 0.36. The range of individual differences for pure-tone intensity discrimination and spectral-shape discrimination was about the same. Two groups of listeners were given extended practice on the profile task, one group that showed low thresholds after an initial 2000 trials of practice and another that showed much higher initial thresholds. All listeners improved during the course of the first 2000 trials of training. Most of the poor listeners continued to improve during 9000 trials of training. Individual differences in the listeners' sensitivity to changes in spectral shape still existed after the extended practice.
Acoustic performance of a concentric circular Helmholtz resonator with an extended neck is investigated theoretically, numerically, and experimentally. The effect of length and shape of, and the perforations on the neck extension is examined on the resonance frequency and the transmission loss. A two-dimensional analytical method is developed for an extended neck with constant cross-sectional area, while a three-dimensional boundary element method is applied for the variable area and perforated extension. Lumped and one-dimensional approaches are also included to illustrate the effect of the higher order modes. For a piston-driven model, predicted resonance frequencies using lumped, one-dimensional, and two-dimensional analytical methods are compared with those from multidimensional boundary element method. Analytical and computational transmission loss predictions for pipe-mounted model are compared to the experimental data obtained from an impedance tube setup. It is shown that the resonance frequency may be controlled by the length, shape, and perforation porosity of the extended neck without changing the cavity volume.
The gammatone filter was imported from auditory physiology to provide a time-domain version of the roex auditory filter and enable the development of a realistic auditory filterbank for models of auditory perception [Patterson et al., J. Acoust. Soc. Am. 98, 1890-1894 (1995)]. The gammachirp auditory filter was developed to extend the domain of the gammatone auditory filter and simulate the changes in filter shape that occur with changes in stimulus level. Initially, the gammachirp filter was limited to center frequencies in the 2.0-kHz region where there were sufficient "notched-noise" masking data to define its parameters accurately. Recently, however, the range of the masking data has been extended in two massive studies. This paper reports how a compressive version of the gammachirp auditory filter was fitted to these new data sets to define the filter parameters over the extended frequency range. The results show that the shape of the filter can be specified for the entire domain of the data using just six constants (center frequencies from 0.25 to 6.0 kHz and levels from 30 to 80 dB SPL). The compressive, gammachirp auditory filter also has the advantage of being consistent with physiological studies of cochlear filtering insofar as the compression of the filter is mainly limited to the passband and the form of the chirp in the impulse response is largely independent of level.
Genetic and environmental interventions that extend life span are a current focus in research on the biology of aging. Most of this work has focused on differences among genotypes and species. A recent study on fruit flies shows that life span extension because of dietary restriction can be highly sex-specific. Here we review the literature on sex-specific effects of 56 genetic and 41 environmental interventions that extend life span in Drosophila melanogaster. We found that only one-sixth of the experiments provided statistical tests of differences in response between males and females, suggesting that sex-specific effects have been largely ignored. When measured, the life span extension was female-biased in 8 of 16 cases, male-biased in 5 of 16 cases, and not significantly different in only 3 of 16 cases. We discuss possible explanations for the sex-specific differences and suggest various ways in which we might test these hypotheses. We argue that understanding sex differences in the response to life span-extending manipulations should lead to new insights about the basic mechanisms that underlie the biology of aging in both sexes.
Seven extended-spectrum beta-lactamases related to TEM and four enzymes derived from SHV-1 were transferred to a common Escherichia coli host so that the activity of a variety of beta-lactams could be tested in a uniform genetic environment. For most derivatives, penicillinase activity was 10% or less than that of strains making TEM-1, TEM-2, or SHV-1 beta-lactamase, suggesting that reduced catalytic efficiency accompanied the broader substrate spectrum. Despite this deficit, resistance to aztreonam, carumonam, cefdinir, cefepime, cefixime, cefmenoxime, cefotaxime, cefotiam, cefpirome, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefuroxime, and E1040 was enhanced. For strains producing TEM-type enzymes, however, MICs of carumonam, cefepime, cefmenoxime, cefotiam, cefpirome, and ceftibuten were 8 micrograms/ml or less. Susceptibilities of cefmetazole, cefotetan, cefoxitin, flomoxef, imipenem, meropenem, moxalactam, temocillin, FCE 22101, and Sch 34343 were unaffected. FCE 22101, imipenem, meropenem, and Sch 34343 were inhibitory for all strains at 1 microgram/ml or less. In E. coli an OmpF- porin mutation in combination with an extended-spectrum beta-lactamase enhanced resistance to many of these agents, but generally by only fourfold. Hyperproduction of chromosomal AmpC beta-lactamase increased resistance to 7-alpha-methoxy beta-lactams but not that to temocillin. When tested at 8 micrograms/ml, clavulanate was more potent than sulbactam or tazobactam in overcoming resistance to ampicillin, while cefoperazone-sulbactam was more active than ticarcillin-clavulanate or piperacillin-tazobactam, especially against TEM-type extended-spectrum beta-lactamases.
A clinical isolate of Pseudomonas aeruginosa RNL-1 showed resistance to extended-spectrum cephalosporins which was inhibited by clavulanic acid. Although this strain contained three plasmids ca. 80, 20, and 4 kb long, the resistance could not be transferred by mating-out assays with P. aeruginosa or Escherichia coli. Cloning of a 2.1-kb Sau3A fragment from P. aeruginosa RNL-1 into plasmid pACYC184 produced pPZ1, a recombinant plasmid that encodes a beta-lactamase. This beta-lactamase (PER-1) had a relative molecular mass of 29 kDa and a pI of 5.4 and was biosynthesized by P. aeruginosa RNL-1 along with a likely cephalosporinase with a pI of 8.7. PER-1 showed a broad substrate profile by hydrolyzing benzylpenicillin, amoxicillin, ticarcillin cephalothin, cefoperazone, cefuroxime, HR 221, ceftriaxone, ceftazidime, and (moderately) aztreonam but not oxacillin, imipenem, or cephamycins. Vmax values for extended-spectrum cephalosporins were uncommonly high, and the affinity of the enzyme for most compounds was relatively low (i.e., high Km). PER-1 activity was inhibited by clavulanic acid, sulbactam, imipenem, and cephamycins but not by EDTA. A 1.1-kb SnaBI fragment from pPZ1 failed to hybridize with plasmids that encode TEM-, SHV-, OXA-, or CARB/PSE-type beta-lactamase or with the ampC gene of P. aeruginosa. However, the same probe appeared to hybridize with chromosomal but not plasmid DNA from P. aeruginosa RNL-1. This study reports the properties of a novel extended-spectrum beta-lactamase in P. aeruginosa which may not be derived by point mutations from previously known enzymes of this species.
We have determined the nucleotide sequence (EMBL accession number, Z 21957) of the cloned chromosomal PER-1 extended-spectrum beta-lactamase gene from a Pseudomonas aeruginosa RNL-1 clinical isolate, blaPER-1 corresponds to a 924-bp open reading frame which encodes a polypeptide of 308 amino acids. This open reading frame is preceded by a -10 and a -35 region consistent with a putative P. aeruginosa promoter. Primer extension analysis of the PER-1 mRNA start revealed that this promoter was active in P. aeruginosa but not in Escherichia coli, in which PER-1 expression was driven by vector promoter sequences. N-terminal sequencing identified the PER-1 26-amino-acid leader peptide and enabled us to calculate the molecular mass (30.8 kDa) of the PER-1 mature form. Analysis of the percent GC content of blaPER-1 and of its 5' upstream sequences, as well as the codon usage for blaPER-1, indicated that blaPER-1 may have been inserted into P. aeruginosa genomic DNA from a nonpseudomonad bacterium. The PER-1 gene showed very low homology with other beta-lactamase genes at the DNA level. By using computer methods, assessment of the extent of identity between PER-1 and 10 beta-lactamase amino acid sequences indicated that PER-1 is a class A beta-lactamase. PER-1 shares around 27% amino acid identity with the sequenced extended-spectrum beta-lactamases of the TEM-SHV series and MEN-1 from Enterobacteriaceae species. The use of parsimony methods showed that PER-1 is not more closely related to gram-negative than to gram-positive bacterial class A beta-lactamases. Surprisingly, among class A beta-lactamases, PER-1 was most closely related to the recently reported CFXA from Bacteroides vulgatus, with which it shared 40% amino acid identity. This work indicates that non-Enterobacteriaceae species such as P. aeruginosa may possess class A extended-spectrum beta-lactamase genes possibly resulting from intergeneric DNA transfer.
In vitro synergy between extended-spectrum cephalosporins and either clavulanic acid or cefoxitin was found for Chryseobacterium meningosepticum isolates during a double-disk assay on an agar plate. An extended-spectrum beta-lactamase (ESBL) gene from a C. meningosepticum clinical isolate was cloned and expressed in Escherichia coli DH10B. Its protein conferred resistance to most beta-lactams including extended-spectrum cephalosporins but not to cephamycins or to imipenem. Its activity was strongly inhibited by clavulanic acid, sulbactam, and tazobactam, as well as by cephamycins and imipenem. Sequence analysis of the cloned DNA fragment revealed an open reading frame (ORF) of 891 bp with a G+C content of 33.9%, which lies close to the expected range of G+C contents of members of the Chryseobacterium genus. The ORF encoded a precursor protein of 297 amino acids, giving a mature protein with a molecular mass of 31 kDa and a pI value of 9.2 in E. coli. This gene was very likely chromosomally located. Amino acid sequence comparison showed that this beta-lactamase, named CME-2 (C. meningosepticum ESBL), is a novel ESBL of the Ambler class A group (Bush functional group 2be), being weakly related to other class A beta-lactamases. It shares only 39 and 35% identities with the ESBLs VEB-1 from E. coli MG-1 and CBL-A from Bacteroides uniformis, respectively. The distribution of bla(CME-2) among unrelated C. meningosepticum species isolates showed that bla(CME-2)-like genes were found in the C. meningosepticum strains studied but were absent from strains of other C. meningosepticum-related species. Each C. meningosepticum strain produced at least two beta-lactamases, with one of them being a noninducible serine ESBL with variable pIs ranging from 7.0 to 8.5.