Effect of nitrate and glucose addition on denitrification and nitric oxide reductase (cnorB) gene abundance and mRNA levels in Pseudomonas mandelii inoculated into anoxic soil.

The effect of glucose addition (0 and 500 µg C g(-1) soil) and nitrate (NO(3)) addition (0, 10, 50 and 500 µg NO(3)-N g(-1) soil) on nitric oxide reductase (cnorB) gene abundance and mRNA levels, and cumulative denitrification were quantified over 48 h in anoxic soils inoculated with Pseudomonas mandelii. Addition of glucose-C significantly increased cnorB(p) (P. mandelii and related species) mRNA levels and abundance compared with soil with no glucose added, averaged over time and NO(3) addition treatments. Without glucose addition, cnorB(p) mRNA levels were higher when 500 µg NO(3)-N g(-1) soil was added compared with other NO(3) additions. In treatments with glucose added, addition of 50 µg NO(3)-N g(-1) soil resulted in higher cnorB(p) mRNA levels than soil without NO(3) but was not different from the 10 and 500 µg NO(3)-N g(-1) treatments. cnorB(p) abundance in soils without glucose addition was significantly higher in soils with 500 µg NO(3)-N g(-1) soil compared to lower N-treated soils. Conversely, addition of 500 µg NO(3)-N g(-1) soil resulted in lower cnorB(p) abundance compared with soil without N-addition. Over 48 h, cumulative denitrification in soils with 500 µg glucose-C g(-1) soil, and 50 or 500 µg NO(3)-N g(-1) was higher than all other treatments. There was a positive correlation between cnorB(p) abundance and cumulative denitrification, but only in soils without glucose addition. Glucose-treated soils generally had higher cnorB(p) abundance and mRNA levels than soils without glucose added, however response of cnorB(p) abundance and mRNA levels to NO(3) supply depended on carbon availability.

The Development of Integration in Marsupial and Placental Limbs.

The morphological interdependence of traits, or their integration, is commonly thought to influence their evolution. As such, study of morphological integration and the factors responsible for its generation form an important branch of the field of morphological evolution. However, most research to date on post-cranial morphological integration has focused on adult patterns of integration. This study investigates patterns of correlation (i.e., morphological integration) among skeletal elements of the fore- and hind limbs of developing marsupial and placental mammals. The goals of this study are to establish how patterns of limb integration vary over development in marsupials and placentals, and identify factors that are likely responsible for their generation. Our results indicate that although the overall pattern of correlation among limb elements is consistent with adult integration throughout mammalian development, correlations vary at the level of the individual element and stage. As a result, the relative integration among fore- and hind limb elements varies dynamically between stages during development in both marsupial and placental mammals. Therefore, adult integration studies of the limbs may not be indicative of developmental integration. Results are also consistent with integration during early limb development being more heavily influenced by genetic and developmental factors, and later by function. Additionally, results are generally consistent with a constraint on marsupial forelimb evolution caused by the functional requirements of the crawl to the teat that operates by limiting morphological variation before and at the time of birth, and not after.

Autophagic dysfunction and autophagosome escape in the mdx mus musculus model of Duchenne muscular dystrophy.

AIM: Duchenne muscular dystrophy is caused by the absence of functional dystrophin protein and results in a host of secondary effects. Emerging evidence suggests that dystrophic pathology includes decreased pro-autophagic signalling and suppressed autophagic flux in skeletal muscle, but the relationship between autophagy and disease progression is unknown. The purpose of this investigation was to determine the extent to which basal autophagy changes with disease progression. We hypothesized that autophagy impairment would increase with advanced disease. METHODS: To test this hypothesis, 7-week-old and 17-month-old dystrophic diaphragms were compared to each other and age-matched controls. RESULTS: Changes in protein markers of autophagy indicate impaired autophagic stimulation through AMPK, however, robust pathway activation in dystrophic muscle, independent of disease severity. Relative protein abundance of p62, an inverse correlate of autophagic degradation, was dramatically elevated with disease regardless of age. Likewise, relative protein abundance of Lamp2, a lysosome marker, was decreased twofold at 17 months of age in dystrophic muscle and was confirmed, along with mislocalization, in histological samples, implicating lysosomal dysregulation in this process. In dystrophic muscle, autophagosome-sized p62-positive foci were observed in the extracellular space. Moreover, we found that autophagosomes were released from both healthy and dystrophic diaphragms into the extracellular environment, and the occurrence of autophagosome escape was more frequent in dystrophic muscle. CONCLUSION: These findings suggest autophagic dysfunction proceeds independent of disease progression and blunted degradation of autophagosomes is due in part to decreased lysosome abundance, and contributes to autophagosomal escape to the extracellular space.

Audit of the management of patients admitted with community acquired pneumonia.

Community acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide. There is evidence that guidelines do guide and standardise management, but with less measurable effect on outcome. We prospectively audited the management of CAP in patients admitted to a Dublin hospital during the winter of 2003/04. The main objective was to evaluate the quality of care for CAP using the BTS guidelines as a standard of management. 164 patients were admitted with CAP during the defined period. Guidelines for assessment of disease severity at presentation were followed in only 56 (34.1%) cases. Appropriate antibiotic therapy was instituted within 8 hours of presentation in 123 (75.0%) cases. The rate of use of a severity assessment score to stratify patients with CAP based on recognized guidelines is low in our hospital. Despite this, the overall mortality rate of 8.5% is comparable with previous results.

Analysis of the albino-locus region of the mouse. I. Origin and viability.

Numerous specific-locus experiments designed to test the mutagenic effect of external radiation have yielded, in over 3,600,000 animals observed, altogether 119 presumed mutations involving the c locus. Of these, 55 were viable and albino (cav), 13 were viable and of various intermediate pigment types (cxv), four were subvital (cas and cxs), seven were neonatally lethal albinos (cal), 28 prenatally lethal albinos (cal); 12 died untested. All of the prenatally lethal and at least one of the neonatally lethal c-locus mutations (cal classes) are probably deficiencies that we have analyzed extensively in other experiments. Since absence of the locus mimics albino in phenotype, the intermediates (cxv and cxs groups) probably resulted from intragenic changes. The class of viable albino mutants (cav) might include, in addition to intragenic changes, some extremely small deficiencies. --The effects on viability of c-locus lethals (cal's) in heterozygous condition are not drastic enough to be perceived in stocks of mixed genetic background except in the case of the two longest known deficiencies and a few others. --Analysis of the relation between radiation treatment and type of c-locus mutants obtained shows that the relative frequency of viable mutations, for each germ-cell type, is greater for low-LET than for neutron irradiation; however, the difference for any individual cell type is not significant. The majority (66.7%) of mutations derived from X- or gamma-ray irradiated spermatogonia are viable, and the proportion of "intermediates" among these viables is similar to that among presumed spontaneous c-locus mutations. No significant dose-rate effect on the proportion of lethals could be demonstrated within the set of mutants induced by low-LET irradiation of spermatogonia. Although sets from other germ-cell stages are too small for statistical tests, the results for oocytes are similar, as far as they go. Furthermore, most of the c-locus mutations induced in spermatogonia, even by high-dose-rate X-ray or gamma irradiation, are of a type most likely to result from single-tract events (62% cxv, cxs, and cav; plus 16% presumed deficiencies not involving the closest marker). These results support the view that most of the reduction in mutation frequency at low dose rates is not due to a change in relative proportion of two-track and one-track ionizing events.

Specific-locus experiments show that female mice exposed near the time of birth to low-LET ionizing radiation exhibit both a low mutational response and a dose-rate effect.

Female mice were exposed to 300 R of 73-93 R/min X-radiation either as fetuses at 18.5 d post conception (p.c.) or within 9 h after birth. Combining the similar results from these two groups yielded a specific-locus mutation frequency of 9.4 X 10(-8) mutation/locus/R, which is statistically significantly higher than the historical-control mutation frequency, but much lower than the rate obtained by irradiating mature and maturing oocytes in adults. Other females, exposed at 18.5 days p.c. to 300 R of 0.79 R/min gamma-radiation, yielded a mutation frequency that was statistically significantly lower than the frequency at high dose rates. The low-dose-rate group also had markedly higher fertility. It appears that the dose-rate effect for mutations induced near the time of birth may be more pronounced than that reported for mature and maturing oocytes of adults. A hypothesis sometimes advanced to explain low mutation frequencies recovered from cell populations that experience considerable radiation-induced cell killing is that there is selection against mutant cells. The reason for the relatively low mutational response following acute irradiation in our experiments is unknown; however, the finding of a dose-rate effect in these oocytes in the presence of only minor radiation-induced cell killing (as judged from fertility) makes it seem unlikely that selection was responsible for the low mutational response following acute exposure. Had selection been an important factor, the mutation frequency should have increased when oocyte killing was markedly reduced.

Correlates of HIV risk-taking behaviors among African-American college students: the effect of HIV knowledge, motivation, and behavioral skills.

This study identifies theoretically based predictors of condom use in a sample of 253 sexually active African-American college students recruited from two historically African-American colleges. The Information-Motivation-Behavioral (IMB) skills model of AIDS-preventive behavior was employed to delineate the roles of HIV/AIDS knowledge, experiences with and attitudes toward condom use, peer influences, perceived vulnerability, monogamy, and behavioral skills. A predictive structural equation model revealed significant predictors of more condom use including: male gender, more sexual HIV knowledge, positive experiences and attitudes about condom use, nonmonogamy, and greater behavioral skills. Results imply that attention to behavioral skills for negotiating safer sex and training in the proper use of condoms are key elements in reducing high risk behaviors. Increasing the specific knowledge level of college students regarding the subtleties of sexual transmission of HIV is important and should be addressed. Heightening students' awareness of the limited protection of serial monogamy, and the need to address gender-specific training regarding required behavior change to reduce transmission of HIV should be an additional goal of college health professionals.

Parents as partners: including mothers and fathers in the treatment of children who stutter.

Parents are frequently included in our intervention methods with children who stutter. However, if we examine the research and clinical literature, we find that we do not distinguish between the roles of mothers and fathers in our diagnosis and intervention procedures. Evidence that mothers and fathers may differ in their interactions with children, in general, and children who stutter, in particular, will be presented. Implications of these findings for our clinical practices will be discussed. By doing so, a case will be made for including both mothers and fathers as partners in the treatment of children who stutter.

Pharmacokinetics of midazolam after intravenous administration to horses.

REASONS FOR PERFORMING THE STUDY: Midazolam is used to control seizures in horses and to enhance muscle relaxation, but its pharmacokinetics are unknown. OBJECTIVE: To determine the pharmacokinetics and sedative effects of midazolam in horses. STUDY DESIGN: Blinded, randomised, crossover design. METHODS: Midazolam was administered i.v. at either 0.05 or 0.1 mg/kg bwt to 6 horses on 2 occasions at least 7 days apart using a crossover design. Blood samples were collected before and at predetermined times through 24 h after administration. Serum midazolam concentrations were determined by a liquid chromatography tandem-mass spectrometry method. Heart and respiratory rates and indices of sedation, ataxia, and sensitivity to stimuli were recorded before and at predetermined times after midazolam administration. RESULTS: Pharmacokinetic analysis was performed on samples from 5 horses in each group. Median total clearance was 10.6 ml/min/kg (range 6.1-15.2 ml/min/kg) and 10.4 ml/min/kg (range 8.4-17.6 ml/min/kg), and median volume of distribution at steady state was 2094 ml/kg (range 2076-2413 ml/kg) and 2822 ml/kg (range 2270-7064 ml/kg) after the 0.05 mg/kg and 0.1 mg/kg bwt doses, respectively. Median distribution half-life was 24 min (range 6-42 min) and 39 min (range 33.6-72 min) and median terminal half-life was 216 min (range 120-248 min) and 408 min (range 192-924 min) after the 0.05 mg/kg and 0.1 mg/kg bwt doses, respectively. Cardiorespiratory parameters and sedation scores did not change. Midazolam caused agitation, postural sway, weakness, and one horse became recumbent after the 0.1 mg/kg bwt dose. CONCLUSIONS: Midazolam produces ataxia and postural sway of short duration after i.v. administration to horses. Sedation was not evident after midazolam administration. Drug redistribution is likely the primary mechanism for the termination of effect. POTENTIAL RELEVANCE: Midazolam produces muscle relaxation but not sedation in adult horses.

Interferometric ether-drift experiment nullified by resynchronization of observer's clocks.

In the Marinov coupled rotating-mirror-interferometer experiment [Czech. J. Phys. B 24, 965 (1974)], a comoving observer must synchronize his clocks after an acceleration. As a result of the resynchronization, the mirrors, according to the observer, reach their fiducial points at different times. The observer interprets this as a twist in theapparatus; when this is corrected by adjusting a mirror, a null result follows.

Speech rates and turn-taking behaviors of children who stutter and their fathers.

Paralinguistic behaviors, including speech rates and turn-taking behaviors, of boys who stutter and boys who do not stutter and their fathers were investigated. Subjects were 11 boys who stutter (mean age = 5:1) and their fathers and 11 age-matched (+/- 3 months) nonstuttering boys (mean age = 5:1) and their fathers. Spontaneous conversational speech was obtained from each father and son during approximately 45 minutes of videotaped free play in a clinic setting. Measures of overall, articulatory, and dyadic speaking rates, interruptions, response time latencies, and disfluency characteristics were derived using the videotapes and computer-assisted analyses of the acoustic signal from each conversational sample. Two-factor repeated measures ANOVAs were performed on each of the paralinguistic variables for the 11 sets of age-matched father-son pairs. Fathers produced faster speaking rates, higher frequencies of interruptions and shorter response time latencies than sons. No significant differences were found in comparisons of the two groups of fathers or of the two groups of children for any of the paralinguistic behaviors. A significant positive correlation was found between the SSI scores of children who stutter and the dyadic speaking rates of these children and their fathers. Results partially extend those of Kelly and Conture (1992) for mothers and children, but some potentially important differences emerge between fathers' and mothers' (para)linguistic behaviors in interaction with their children.

Speaking rates, response time latencies, and interrupting behaviors of young stutterers, nonstutterers, and their mothers.

The purpose of this study was to investigate the speaking rates, interrupting behaviors, and response time latencies (RTL) produced by stuttering and nonstuttering children and their mothers, and the relationship these three paralinguistic behaviors have to children's speech disfluencies. Subjects were 13 boys who stutter (mean age = 4:0) and their mothers and 13 nonstuttering boys (mean age = 4:0) and their mothers. No significant differences were found between the two groups of children or between the two groups of mothers for any of the three paralinguistic behaviors with the exception that the mothers of nonstuttering children exhibited significantly (p < 0.01) faster rates of speech than either group of children. A strong positive correlation (r = .84) was found between stuttering children's scores on the Stuttering Severity Instrument (Riley, 1980) and the durations of the overlapping portions of their mothers' interruptions (i.e., their simultalk). Findings of this study are taken to support a facilitative demands-capacities model of conversational interaction in which mothers adjust the demands of their speaking models in response to their children's demonstrated capacities for fluent speech production.

Specific-locus mutation frequencies in mouse stem-cell spermatogonia at very low radiation dose rates.

Experiments were undertaken to augment the information on the lowest radiation dose rates feasible for scoring transmitted induced mutations detected by the specific-locus method in the mouse. This is the type of information most suitable for estimating genetic hazards of radiation in man. The results also aid in resolving conflicting possibilities about the relationship between mutation frequency and radiation dose rate at low dose rates. There was no statistically significant difference between mutation frequencies obtained in spermatogonia with 300 R (1 R = 2.6 x 10(-4) coulombs/kg) of gamma radiation at two different dose rates, 0.005 and 0.0007 R/min, or between either of these frequencies and data obtained earlier at dose rates of 0.8 R/min and below. This supports the view in an earlier publication by one of us (W.L.R.) that, at approximately 0.8 R/min and below, mutation frequency is independent of dose rate. Because this independence is now shown to extend over the more than 1000-fold range from 0.8 to 0.0007 R/min, it seems likely that it would hold at still lower dose rates, perhaps even to the much lower dose rates encountered in most human exposures.

Mutation frequencies in male mice and the estimation of genetic hazards of radiation in men.

Estimation of the genetic hazards of ionizing radiation in men is based largely on the frequency of transmitted specific-locus mutations induced in mouse spermatogonial stem cells at low radiation dose rates. The publication of new data on this subject has permitted a fresh review of all the information available. The data continue to show no discrepancy from the interpretation that, although mutation frequency decreases markedly as dose rate is decreased from 90 to 0.8 R/min (1 R = 2.6 x 10(-4) coulombs/kg) there seems to be no further change below 0.8 R/min over the range from that dose rate of 0.0007 R/min. Simple mathematical models are used to compute: (a) a maximum likelihood estimate of the induced mutation frequency at the low dose rates, and (b) a maximum likelihood estimate of the ratio of this to the mutation frequency at high dose rates in the range of 72 to 90 R/min. In the application of these results to the estimation of genetic hazards of radiation in man, the former value can be used to calculate a doubling dose--i.e, the dose of radiation that induces a mutation frequency equal to the spontaneous frequency. The doubling dose based on the low-dose-rate data compiled here is 110 R. The ratio of the mutation frequency at low dose rate to that at high dose rate is useful when it becomes necessary to extrapolate from experimental determinations, or from human data, at high dose rates to the expected risk at low dose rates. The ratio derived from the present analysis is 0.33.

Young stutterers' nonspeech behaviors during stuttering.

The purpose of this study was to assess the nonspeech behaviors associated with young stutterers' stuttering and normally fluent children's comparable fluent utterances. Subjects were 28 boys and 2 girls who stutter (mean age = 54 months) and 28 boys and 2 girls who do not stutter (mean age = 54 months). Each child and his or her mother were audio-video recorded during a loosely structured, 30-min conversation. Sixty-six different nonspeech behaviors associated with 10 randomly selected stutterings per stutterer and 10 comparable fluent utterances per normally fluent child were assessed by means of frame-by-frame analysis of the audio-video recordings. Results indicate that (a) young stutterers produce significantly more nonspeech behaviors during stuttered words than do normally fluent children during comparable fluent words, (b) young stutters produce significantly more head turns left, blinks, and upper lip raising during stuttered words than do normally fluent children during comparable fluent words, and (c) talker group membership could be significantly determined on the basis of certain types of nonspeech behaviors despite considerable overlap in frequency and type of nonspeech behavior between the two talker groups. Findings suggest that children can be classified as stutterers on the basis of their nonspeech behaviors and that these behaviors may reflect a variety of cognitive, emotional, linguistic, and physical events associated with childhood stuttering.

Orofacial muscle activity of children who stutter: a preliminary study.

This study was a preliminary investigation of the relations between stuttering development and the maturation of speech motor processes. Electromyographic (EMG) activity was recorded from the orofacial muscles of children who stutter and their normally fluent peers during fluent and disfluent speech. Nine children who stutter (8 boys and 1 girl), ranging in age from 2:7 to 14:0, and 9 age- and sex-matched children who do not stutter were subjects. Pairs of surface EMG electrodes were placed on children's faces overlying the anterior belly of the digastric (ABD), levator labii superior (ULIP), and orbicularis oris inferior (LLIP) muscles. Twenty segments of stuttered (for the children who stutter) and perceptually fluent speech were extracted from children's conversational speech samples. Spectra of the amplitude envelopes of the EMG activity were computed. The 3 oldest children who stutter showed evidence of tremorlike oscillations of EMG activity in the 5 to 15 Hz range during stuttering in either ULIP, LLIP, or ABD muscles. The younger children who stutter and the children who do not stutter demonstrated primary spectral peaks in the 1 to 4 Hz range during stuttered and/or perceptually fluent speech. It is hypothesized that the emergence of tremorlike instabilities in the speech motor processes of children who stutter may coincide with aspects of their general neural maturation and with the development of stuttering.

Intermediates of the in vitro assembly and disassembly of southern bean mosaic virus.

Southern bean mosaic virus (SBMV) was swollen by treatment with EDTA at pH 7.5 and dissociated into RNA and protein in 1 M NaCl. Aliquots of this preparation were diluted with appropriate buffers to obtain samples in varying concentrations of NaCl, and components of these samples were sedimented through sucrose solutions and dissolved in 0.01 M Tris-HCI buffer, pH 7.5. The protein content and sedimentation properties of components in these preparations were determined. When the NaCl molarity in the treatment exceeded 0.6 M the preparations contained RNA with approximately six protein subunits per SBMV RNA molecule. The protein content of the preparations increased from 30 protein subunits per RNA molecule to 145 protein subunits per RNA molecule as the NaCl molarity used in the treatment was decreased from 0.5 to 0.1 M. The positions of sedimentation of components in these preparations in density gradient centrifugation were intermediate between those of RNA and EDTA-swollen virus. The sedimentation rate of these assembled components increased as the NaCl molarity used in the treatment was decreased. Similar components were assembled when preparations of RNA and protein dissociated from SBMV by dialysis in neutral buffers containing EDTA and 1 M NaCl were diluted to lower NaCl molarities. When SBMV was swollen by treatment with EDTA and dissociated in various concentrations of NaCl, the components formed were similar to those obtained by assembly in the same NaCl molarities. Preparations in the pH 7.5 buffer contained single components which sedimented at 56 S, 55 S, 54 S, 51 S, 46 S, 38 S, 33 S, and 24 S. With the exception of the 24 S component, components formed by disassembly in the same NaCl molarities and dissolved in pH 5.0 buffer sedimented faster.