Treatment of biofilm infections on implants with low-frequency ultrasound and antibiotics

Medical implants are sometimes colonized by biofilm-forming bacteria, which are very difficult to treat effectively. The combination of gentamicin and ultrasonic exposure for 24 hours was previously shown to reduce the viability of Escherichia coli biofilms in vivo. This article shows that such treatment for 48 hours reduced viable E coli bacteria to nearly undetectable levels. However, when Pseudomonas aeruginosa biofilms were implanted and treated for 24 and 48 hours, no significant ultrasonic-enhanced reduction of viable bacteria was observed. The difference in response of these 2 organisms is attributed to greater impermeability and stability of the outer membrane of P aeruginosa.

Pathoscope: species identification and strain attribution with unassembled sequencing data

Emerging next-generation sequencing technologies have revolutionized the collection of genomic data for applications in bioforensics, biosurveillance, and for use in clinical settings. However, to make the most of these new data, new methodology needs to be developed that can accommodate large volumes of genetic data in a computationally efficient manner. We present a statistical framework to analyze raw next-generation sequence reads from purified or mixed environmental or targeted infected tissue samples for rapid species identification and strain attribution against a robust database of known biological agents. Our method, Pathoscope, capitalizes on a Bayesian statistical framework that accommodates information on sequence quality, mapping quality, and provides posterior probabilities of matches to a known database of target genomes. Importantly, our approach also incorporates the possibility that multiple species can be present in the sample and considers cases when the sample species/strain is not in the reference database. Furthermore, our approach can accurately discriminate between very closely related strains of the same species with very little coverage of the genome and without the need for multiple alignment steps, extensive homology searches, or genome assembly--which are time-consuming and labor-intensive steps. We demonstrate the utility of our approach on genomic data from purified and in silico "environmental" samples from known bacterial agents impacting human health for accuracy assessment and comparison with other approaches.

Pulsed ultrasound enhances the killing of Escherichia coli biofilms by aminoglycoside antibiotics in vivo

Escherichia coli biofilms on two polyethylene disks were implanted subcutaneously into rabbits receiving systemic gentamicin. Ultrasound was applied for 24 h to one disk. Both disks were removed, and viable bacteria were counted. Pulsed ultrasound significantly reduced bacterial viability below that of nontreated biofilms without damage to the skin.

Ultrasonic enhancement of antibiotic action on Escherichia coli biofilms: an in vivo model

Biofilm infections are a common complication of prosthetic devices in humans. Previous in vitro research has determined that low-frequency ultrasound combined with aminoglycoside antibiotics is an effective method of killing biofilms. We report the development of an in vivo model to determine if ultrasound enhances antibiotic action. Two 24-h-old Escherichia coli (ATCC 10798) biofilms grown on polyethylene disks were implanted subcutaneously on the backs of New Zealand White female rabbits, one on each side of the spine. Low-frequency (28.48-kHz) and low-power-density (100- and 300-mW/cm2) continuous ultrasound treatment was applied for 24 h with and without systemic administration of gentamicin. The disks were then removed, and the number of viable bacteria on each disk was determined. At the low ultrasonic power used in this study, exposure to ultrasound only (no gentamicin) caused no significant difference in bacterial viability. In the presence of antibiotic, there was a significant reduction due to 300-mW/cm2 ultrasound (P = 0.0485) but no significant reduction due to 100-mW/cm2 ultrasound. Tissue damage to the skin was noted at the 300-mW/cm2 treatment level. Further development of this technique has promise in treatment of clinical implant infections.

Effects of alfalfa silage chop length and supplementary long hay on chewing and milk production of dairy cows

Twelve lactating, multiparous Holstein cows were used to evaluate the effects of silage chop length and proportion of long hay in low and adequate forage fiber diets on chewing activities and productivity of cows fed barley-based concentrates. Diets were designed with two forage:concentrate ratios (low forage fiber, 35:65; adequate forage fiber, 65:35), combined with two theoretical chop lengths of alfalfa silage (fine, 5 mm; coarse, 10 mm), and three proportions of long-stemmed alfalfa hay (0, 10, and 20% of DMI). Increasing the chop length of silage in low forage fiber diets did not affect DMI but increased FCM; in adequate forage fiber diets, it decreased DMI and FCM. Addition of hay to silage diets increased DMI, but not FCM yield. Increasing silage chop length in diets formulated below the recommended minimal amount of NDF from forage promoted rumination and increased milk production while maintaining milk fat content and DMI. Addition of a small amount of hay to low forage fiber diets was less effective than increased particle length of silage. In adequate forage fiber diets, finely chopped silage can be used effectively.

A comparison of the use of tympanic, axillary, and rectal thermometers in infants

This study examined the relationship between three instruments used in measuring tympanic, axillary, and rectal temperatures in infants less than 1 year of age. Temperatures were measured by Oto-temp Pedi Q tympanic thermometers, Becton Dickinson axillary thermometer, and rectal thermometers. A convenience sample of 5 infants less than 90 day and 54 greater than 90 days with fever, as well as 34 infants less than 90 days and 27 infants greater than 90 days without fever were studied. Correlations of infants less than 90 days and greater 90 days of age, as well as differences between infant temperature with and without fevers as variables, were examined. Results indicated a strong statistical relationship between Oto-Temp Pedi Q, Becton Dickinson axillary temperatures, and rectal temperatures, but not strong enough to base critical clinical decisions. Age and presence or absence of fever significantly affected the relationships between thermometers.

The mycobactericidal efficacy of ortho-phthalaldehyde and the comparative resistances of Mycobacterium bovis, Mycobacterium terrae, and Mycobacterium chelonae

OBJECTIVES

To assess the mycobactericidal efficacy of an agent relatively new to disinfection, ortho-phthalaldehyde (OPA) and to compare the resistances of three Mycobacterium species. Mycobacterium bovis (strain BCG) was compared with Mycobacterium chelonae and Mycobacterium terrae to investigate the feasibility of using either of the latter two species in tuberculocidal testing. M. chelonae (a rapid grower) and M. terrae (an intermediate grower) both grow faster and are less virulent than M. bovis (a slow grower).

DESIGN

The quantitative suspension protocol specified by the Environmental Protection Agency (EPA), the Tuberculocidal Activity Test Method (EPA test), was used throughout this study. Standard suspensions of all three species were prepared in a similar manner. Two suspensions of M. bovis, created in different laboratories, were used. These were tested against two concentrations of alkaline glutaraldehyde to provide reference data. Two concentrations of OPA were evaluated against all mycobacterial test suspensions. Four replicates of each organism-disinfectant combination were performed.

RESULTS

Results were assessed by analysis of variance. M. terrae was significantly more resistant to 0.05% OPA than either M. bovis or M. chelonae. At 0.21% OPA, M. terrae was slightly more susceptible than one test suspension of M. bovis, but not significantly different from the other. M. chelonae was significantly less resistant than the other species at both OPA concentrations. At their respective minimum effective concentration, OPA achieved a 6-log10 reduction of M. bovis in nearly one sixth the time required by glutaraldehyde (5.5 minutes vs. 32 minutes).

CONCLUSIONS

These data, along with other recent studies, lend support to the idea that M. terrae may be a suitable test organism for use in the tuberculocidal efficacy testing of disinfectants. They also confirm the relatively rapid tuberculocidal activity of OPA.

Optimal neutral detergent fiber concentration of barley-based diets for lactating dairy cows

Twelve lactating, multiparous Holstein cows were used in two experiments, designed as 6 x 6 Latin squares with 28-d periods, to evaluate the effects of increasing the NDF concentration of diets consisting of barley-based concentrates and various forages. Diets were designed in a 3 x 2 factorial set with three concentrations of total dietary NDF (32, 36, and 40%) combined with two sources of forage. In Experiment 1, cows received alfalfa hay (45.1% NDF) or orchardgrass hay (54.0% NDF). In Experiment 2, cows received alfalfa hay (42.5% NDF) or corn silage (50.5% NDF). Cows ate more DM when fed alfalfa hay than when fed orchardgrass hay or corn silage. Intake of DM decreased as NDF concentration increased for alfalfa hay and corn silage diets, but a positive quadratic relationship between DMI and NDF occurred for orchardgrass hay. As dietary NDF increased, milk yield decreased, but fat percentage increased. Time spent ruminating was associated positively with concentration of NDF and was similar for diets formulated with various forages at the same dietary NDF concentration. Regardless of forage source, increasing dietary NDF concentration did not affect FCM yields because, as NDF intake increased, energy intake decreased. With consumer demand for low fat milk products, high yield of low fat milk is advantageous, and the minimal amount of fiber necessary in dairy cattle diets may be less than currently recommended. Further research is required to determine the long-term effects on health and longevity of low fiber diets fed to cows.

The Effects of Repeated Administrations on Self-Report and Parent-Report Scales

The use of repeated measures to track the out-come of psychosocial interventions is becoming common practice in most organizations. One threat with this methodology is the retest artifact. This artifact is defined by a systematic change in scores for individuals who repeatedly complete an outcome instrument yet do not receive an) formal treatment. The retest artifact can call into question the validity of change associated with school-based treatment programs when this change is based upon repeated testing using outcome instruments. This study directly assessed the retest effect for both a youth and an adult psychosocial outcome measure. The frequency of retest administrations was systematically varied (weekly, biweekly, monthly, pre/post testing) over a 9-week period using a youth parent-report and an adult self-report Outcome Questionnaire. Results indicate a statistically significant improvement in functioning at the time of the second administration regardless of the lapse in time for the adult measure and a steady improvement in functioning for the parent-report youth measure. Implications of this finding for evaluating psychosocial interventions are discussed.

Distribution of doxorubicin in rats undergoing ultrasonic drug delivery

Ultrasound (US) increases efficacy of drugs delivered from micelles, but the pharmacokinetics have not been studied previously. In this study, US was used to deliver doxorubicin (Dox) sequestered in micelles in an in vivo rat model with bilateral leg tumors. One of two frequencies with identical mechanical index and intensity was delivered for 15 min to one tumor immediately after systemic injection of micellar Dox. Pharmacokinetics in myocardium, liver, skeletal muscle, and tumors were measured for 1 week. When applied in combination with micellar Dox, the ultrasoincated tumor had higher Dox concentrations at 30 min, compared to bilateral noninsonated controls. Initially, concentrations were highest in heart and liver, but within 24 h they decreased significantly. From 24 h to 7 days, concentrations remained highest in tumors, regardless of whether they received US or not. Comparison of insonated and noninsonated tumors showed 50% more Dox in the insonated tumor at 30 min posttreatment. Four weekly treatment produced additional Dox accumulation in the myocardium but not in liver, skeletal leg muscle, or tumors compared to single treatment. Controls showed that neither US nor the empty carrier impacted tumor growth. This study shows that US causes more release of drug at the targeted tumor.

Characterizing rumination patterns of dairy cows using spectral analysis

Spectral analysis techniques were used to characterize the cyclical variation in rumination behavior of cows. Four Holstein cows were fed twice daily a diet of 60% high-moisture shelled corn-based concentrate, 15% first-cut alfalfa-grass hay and 25% second-cut alfalfa silage. The number of minutes that each cow spent ruminating was determined for 15-min intervals during six consecutive days. Rumination data then were characterized using Fourier harmonic analysis to decompose the total sum of squares into 288 orthogonal components due to different rumination wavelengths. Rumination patterns for all cows consisted mainly of wavelengths that were harmonics of a 24-h cycle, indicating a circadian pattern of rumination. Differences in rumination patterns between cows occurred mainly at wavelengths of less than 2 h. Rumination patterns of two of the four cows were more complex, and consisted of high-frequency, non-24-h harmonic wavelengths in addition to the circadian pattern. Spectral analysis can be used to identify the component cycles of rumination patterns of individual animals, which can then be used to determine the effects of dietary or other manipulations on rumination behavior.

Role of frequency and mechanical index in ultrasonic-enhanced chemotherapy in rats

PURPOSE

The therapeutic effect of ultrasound and micellar-encapsulated doxorubicin was studied in vivo using a tumor-bearing rat model with emphasis on how tumor growth rate is affected by ultrasonic parameters such as frequency and intensity.

METHODS

This study employed ultrasound of two different frequencies (20, 476 kHz) and two pulse intensities, but identical mechanical indices and temporal average intensities. Ultrasound was applied weekly for 15 min to one of two bilateral leg tumors (DHD/K12/TRb colorectal epithelial cell line) in the rat model immediately after intravenous injection of micelle-encapsulated doxorubicin. This therapy was applied weekly for 6 weeks.

RESULTS

Results showed that tumors treated with drug and ultrasound displayed, on average, slower growth rates than non-insonated tumors (P = 0.0047). However, comparison between tumors that received 20 or 476-kHz ultrasound treatments showed no statistical difference (P = 0.9275) in tumor growth rate.

CONCLUSION

Application of ultrasound in combination with drug therapy was effective in reducing tumor growth rate, irrespective of which frequency was employed.

Combination therapy with folic acid and methionine in the prevention of retinoic acid-induced cleft palate in mice

BACKGROUND

During formation of the secondary palate, clefting may result when critical developmental events are altered. The purpose of this study was to reduce the incidence of retinoic acid (RA)-induced cleft palate (CP) in mice by the co-administration of folic acid (FA), methionine (ME) or a combination of both.

METHODS

Four groups of time-pregnant Swiss Webster mice were injected intraperitoneally with 50 mg/kg RA on gestational day (GD) 10. Likewise, 4.0 mg/kg FA and 187 mg/kg ME were administered on GD 8-11. The experiment included a control group (RA plus H2O) and three experimental groups, (RA plus therapeutic doses of FA, ME, or FA + ME). Necropsies were carried out on GD 18 and pups were analyzed for teratogenic effects.

RESULTS

Litters that received no therapy exhibited 100% CP with individual pups showing 76% susceptibility. Each therapy administered separately reduced the frequency of CP to approximately 6%, and the combination of FA and ME completely prevented the occurrence of RA-induced cleft palate (0%). A second experiment was conducted in which therapy levels were decreased by 25%. Litters that did not receive therapy experienced 100% clefting and individual pups exhibited CP at 86%. These therapies administered separately did not alter significantly the frequency of cleft palate. The combined doses of FA and ME, however, lowered significantly the frequency of cleft palate to 46%. Decreases in limb and tail defects with FA + ME therapy were also observed in both experiments.

CONCLUSIONS

Although FA and ME, at appropriate levels, can reduce individually the frequency of RA-induced cleft palate and other defects in mice, the results from the present study suggest that there is an additive interaction between the two therapeutic agents that can reduce further the teratogenic impact of RA. Further studies are needed to assess the mechanism of action of concomitant doses of FA and ME in the reduction of drug-induced birth defects.

Aerobic and resistance exercise sequence affects excess postexercise oxygen consumption

Excess postexercise oxygen consumption (EPOC) may describe the impact of previous exercise on energy metabolism. Ten males completed Resistance Only, Run Only, Resistance-Run, and Run-Resistance experimental conditions. Resistance exercise consisted of 7 lifts. Running consisted of 25 minutes of treadmill exercise. Vo(2) was determined during treadmill exercise and after each exercise treatment. Our findings indicated that treadmill exercise Vo(2) was significantly higher for Resistance-Run compared with Run-Resistance and Resistance Only at all time intervals. At 10 minutes postexercise, Vo(2) was greater for Resistance Only and Run-Resistance than for Resistance-Run. At 20 and 30 minutes, Vo(2) following Resistance Only was significantly greater than following Run Only. In conclusion, EPOC is greatest following Run-Resistance; however, treadmill exercise is more physiologically difficult following resistance exercise. Furthermore, the sequence of resistance and treadmill exercise influences EPOC, primarily because of the effects of resistance exercise rather than the exercise combination. We recommend performing aerobic exercise before resistance exercise when combining them into 1 exercise session.

Effects of predation environment and food availability on somatic growth in the Livebearing Fish Brachyrhaphis rhabdophora (Pisces: Poeciliidae)

Variation in somatic growth rates is of great interest to biologists because of the relationship between growth and other fitness-determining traits, and it results from both genetic and environmentally induced variation (i.e. plasticity). Theoretical predictions suggest that mean somatic growth rates and the shape of the reaction norm for growth can be influenced by variation in predator-induced mortality rates. Few studies have focused on variation in reaction norms for growth in response to resource availability between high-predation and low-predation environments. We used juvenile Brachyrhaphis rhabdophora from high-predation and low-predation environments to test for variation in mean growth rates and for variation in reaction norms for growth at two levels of food availability in a common-environment experiment. To test for variation in growth rates in the field, we compared somatic growth rates in juveniles in high-predation and low-predation environments. In the common-environment experiment, mean growth rates did not differ between fish from differing predation environments, but the interaction between predation environment and food level took the form of a crossing reaction norm for both growth in length and mass. Fish from low-predation environments exhibited no significant difference in growth rate between high and low food treatments. In contrast, fish from high-predation environments exhibited variation in growth rates between high and low food treatments, with higher food availability resulting in higher growth rates. In the field, individuals in the high-predation environment grow at a faster rate than those in low-predation environments at the smallest sizes (comparable to sizes in the common-environment experiment). These data provide no evidence for evolved differences in mean growth rates between predation environments. However, fish from high-predation environments exhibited greater plasticity in growth rates in response to resource availability suggesting that predation environments may exhibit increased variation in food availability for prey fish and consequent selection for plasticity.

Cytotoxicity of Atriplex confertifolia

The search for cancer treatment continues to be a global effort. As part of this global effort, many natural products have been tested against cancer cell lines, mostly from tropically located plants. This study reports that extracts of Atriplex confertifolia (Torr. and Frem.) S. Watson (Chenopodiaceae), a native North American plant (also known as shadscale or saltbush), has significant bioactivity against human breast cancer cell lines MCF-7, MDA-MB 435, MDA-MB 231, and HeLa cells (cervical cancer cells). The bioactivity of A. confertifolia extracts on these cells lines was compared to an FDA-approved cancer drug (Onxol((R))) and an industry-standard leukocyte control cell line. Active portions of the extracts were found primarily in the polar fractions of the plant. A dose-response curve of the extracts displayed significant cell death similar to Onxol((R)). The plant extracts did not significantly inhibit the viability of the leukocyte cell line. In a timed study, over 90% of cell lines MDA-MB 435 and HeLa died after 24 hours. Cell death appears to result from apoptosis.

Costs of treating depression with individual versus family therapy

Depression is one of the most common concerns that bring clients to treatment. Although marriage and family therapy has been shown to be an effective treatment, little research exists regarding the cost-effectiveness of related services. In this study, we examined claims data for 164,667 individuals diagnosed with depression to determine (a) differences in the cost of treating depression according to type of therapy and license type, (b) differences in recidivism rates by age, gender, type of therapy, and type of mental health professional, and (c) differences in cost-effectiveness by therapy modality and type of professional. The results showed that services provided by marriage and family therapists resulted in the lowest recidivism rate, and family therapy services were the least expensive.

Developmental toxicity of carbon black oil in mice

BACKGROUND

Carbon black oil (CBO) is a refinery side-stream product used to produce asphalt and other commercial products. CBO contains several classes of hydrocarbons, several of which are known to exhibit systemic and gestational toxicities, making this mixture a candidate for causing reproductive toxicity.

METHODS

Swiss-Webster mice were administered CBO (300, 350, 400 mg/kg/day) via oral gavage in a dosage volume of 10 microl/g body weight on gestation days (GD) 6-15. Uterine contents were evaluated on GD 18.

RESULTS

Treatment with CBO at all dosage levels resulted in a high frequency of maternal clinical symptoms and a decrease in maternal weight gain. Decreased fetal viability was observed, manifested as a decrease in viable implants and, in a high percentage of treated dams, as early resorption of the entire litter. A significant reduction in fetal weight was also observed. However, neither structural malformations nor developmental delays in ossification were observed in any of the living offspring. To minimize maternal toxicity, the dosage range was lowered (100, 200, 300 mg/kg/day), and the concentration was adjusted such that the volume administered to each dam was decreased by 20%. In this trial, the only maternal effect observed was an increase in maternal liver weight at 200 and 300 mg/kg. The fetal lethality effects observed previously were reduced substantially. Nevertheless, the frequency of resorption among all treatment groups was higher statistically than in controls.

CONCLUSIONS

These data support the hypothesis that CBO is reproductively toxic in Swiss-Webster mice at oral doses of >/=100 mg/kg/day.