In vivo antibacterial efficacy of ultrasound after hand and rotary instrumentation in human mandibular molars

The purpose of this prospective, randomized, single-blind study was to compare the in vivo antibacterial efficacy of a hand/rotary technique versus a hand/rotary/ultrasound technique in mesial root canals of necrotic mandibular molars. The hand/rotary group consisted of 16 mesial roots prepared with a hand/rotary technique. The hand/rotary/ultrasound group consisted of 15 mesial roots prepared similarly, followed by 1 minute of ultrasonic irrigation per canal with an ultrasonic needle in a MiniEndo unit and 15 mL/canal of 6.0% sodium hypochlorite. Canals were sampled before and after instrumentation and after 1 minute of ultrasonic irrigation. Samples were incubated anaerobically on reduced blood agar for 7 days at 37 degrees C, and colony-forming units (CFUs) were counted. The addition of 1 minute of ultrasonic irrigation resulted in significant (p = .0006) reduction in CFU count and positive cultures (p = .0047). Logistic regression analysis indicated the addition of ultrasonic irrigation was 7 times more likely to yield a negative culture.     

Using evidence to enhance the recovery of patients undergoing colorectal surgery: part 2

This is the second part of a three-part series describing how an enhanced recovery clinical pathway uses a multidisciplinary team to reduce postoperative stress and complications, improve recovery, and decrease hospital length of stay without affecting patient safety for patients undergoing colorectal surgery. Last month, patient education and discharge planning were discussed. This part discusses multimodal analgesia and standardized postoperative nausea and vomiting prophylaxis. Next month, fluids, diet, tubes and drains, and early mobilization will be discussed.     

Reverberation negatively impacts musical sound quality for cochlear implant users

Abstract

Objective

Satisfactory musical sound quality remains a challenge for many cochlear implant (CI) users. In particular, questionnaires completed by CI users suggest that reverberation due to room acoustics can negatively impact their music listening experience. The objective of this study was to more specifically characterize of the effect of reverberation on musical sound quality in CI users, normal hearing (NH) non-musicians, and NH musicians using a previously designed assessment method, called Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor (CI-MUSHRA).

Methods

In this method, listeners were randomly presented with an anechoic musical segment and five-versions of this segment in which increasing amounts of reverberation were artificially added. Participants listened to the six reverberation versions and provided sound quality ratings between 0 (very poor) and 100 (excellent).

Results

Results demonstrated that on average CI users and NH non-musicians preferred the sound quality of anechoic versions to more reverberant versions. In comparison, NH musicians could be delineated into those who preferred the sound quality of anechoic pieces and those who preferred pieces with some reverberation.

Discussion/Conclusion

This is the first study, to our knowledge, to objectively compare the effects of reverberation on musical sound quality ratings in CI users. These results suggest that musical sound quality for CI users can be improved by non-reverberant listening conditions and musical stimuli in which reverberation is removed.     

Inhibin A is an endocrine stimulator of bone mass and strength

Gonadal function plays a major role in bone homeostasis. It is widely held that the skeletal consequences of hypogonadism are solely due to a loss of sex steroids; however, increases in bone turnover begin during perimenopause before decreases in serum estradiol levels. These data and our demonstration that inhibins acutely regulate bone cell differentiation in vitro led us to test whether inhibin A (InhA) regulates bone mass in vivo. Using a transgenic model of inducible human InhA expression, InhA increased total body bone mineral density, increased bone volume, and improved biomechanical properties at the proximal tibia in intact mice and also prevented the loss of BMD and bone volume and strength associated with gonadectomy at both the spine and proximal tibia. In addition, InhA increased mineral apposition rate, double-labeled surface, and serum osteocalcin levels in vivo and osteoblastogenesis ex vivo without affecting osteoclast number or activity. Together these results demonstrate novel stimulatory effects of InhA on the skeleton in vivo. These studies provide in vivo evidence demonstrating that gonadal factors other than sex steroids play an important role in regulating bone mass and strength and, combined with our previous clinical data, suggest that gonadal InhA may be a component of the normal endocrine repertoire that regulates bone quality in both the axial and appendicular skeleton.     

Early detection and prediction of cardiotoxicity in chemotherapy-treated patients

As breast cancer survival increases, cardiotoxicity associated with chemotherapeutic regimens such as anthracyclines and trastuzumab becomes a more significant issue. Assessment of the left ventricular (LV) ejection fraction fails to detect subtle alterations in LV function. The objective of this study was to evaluate whether more sensitive echocardiographic measurements and biomarkers could predict future cardiac dysfunction in chemotherapy-treated patients. Forty-three patients diagnosed with breast cancer who received anthracyclines and trastuzumab therapy underwent echocardiography and blood sampling at 3 time points (baseline and 3 and 6 months during the course of chemotherapy). The LV ejection fraction; peak systolic myocardial longitudinal, radial, and circumferential strain; echocardiographic markers of diastolic function; N-terminal pro-B-type natriuretic peptide; and high-sensitivity cardiac troponin I were measured. Nine patients (21%) developed cardiotoxicity (1 at 3 months and 8 at 6 months) as defined by the Cardiac Review and Evaluation Committee reviewing trastuzumab. A decrease in longitudinal strain from baseline to 3 months and detectable high-sensitivity cardiac troponin I at 3 months were independent predictors of the development of cardiotoxicity at 6 months. The LV ejection fraction, parameters of diastolic function, and N-terminal pro-B-type natriuretic peptide did not predict cardiotoxicity. In conclusion, cardiac troponin plasma concentrations and longitudinal strain predict the development of cardiotoxicity in patients treated with anthracyclines and trastuzumab. The 2 parameters may be useful to detect chemotherapy-treated patients who may benefit from alternative therapies, potentially decreasing the incidence of cardiotoxicity and its associated morbidity and mortality.     

Proofreading DNA: recognition of aberrant DNA termini by the Klenow fragment of DNA polymerase I.

Fluorescence depolarization decays were measured for 5-dimethylaminonaphthalene-1-sulfonyl (dansyl) probes attached internally to 17-mer.27-mer oligonucleotides bound to Klenow fragment of DNA polymerase I. The time-resolved motions of the dansyl probes were sensitive indicators of DNA-protein contacts, showing that the protein binds to DNA with two footprints, corresponding to primer termini at either the polymerase or 3'-5' exonuclease sites. We examined complexes of Klenow fragment with DNAs containing various base mismatches. Single mismatches at the primer terminus caused a 3- to 4-fold increase in the equilibrium partitioning of DNA into the exonuclease site; the largest effects were observed for purine-purine mismatches. Two or more consecutive G.G mismatches caused the DNA to bind exclusively at the exonuclease site, with a partitioning constant at least 250-fold greater than that of the corresponding matched DNA sequence. Internal single mismatches produced larger effects than the same mismatch at the primer terminus, with a delta delta G relative to the matched sequence of -1.1 to -1.3 kcal/mol for mismatches located 2, 3, or 4 bases from the primer terminus. Although part of the observed effects may be attributed to the increased melting capacity of the DNA, it appears that the polymerase site also promotes movement of DNA into the exonuclease site by rejecting aberrant primer termini. These effects suggest that the polymerase and exonuclease sites act together to recognize specific errors that distort the primer terminus, such as frameshifts, in addition to proofreading misincorporated bases.     

Effects of aging, message repetition, and note-taking on memory for health information

This study investigated whether repetition improves older adults' memory for health service appointment messages delivered by automated telephone systems. Whereas imposed repetition reduces age differences in memory (Morrow, Leirer, Carver, Tanke, & McNally, 1999), the present study examined the effect of optional repetition. Both older and younger participants in Experiment 1 chose to repeat messages. More repetition, higher cognitive ability (working memory and processing speed), and younger age were associated with better memory for appointment information. The effect of age was eliminated when cognitive ability, but not repetition, was controlled. Thus, older adults used optional repetition in automated systems, but this strategy did not eliminate age differences in memory. In Experiment 2, older as well as younger adults took accurate notes and also repeated messages. Both note-taking and message repetition improved memory for the messages but did not reduce age differences. These findings suggest that older as well as younger adults use presentation strategies in automated messaging systems. Older adults may not take full advantage of these strategies, perhaps because of age-related declines in self-initiated or metacognitive processes.     

Detection of Chronic Wasting Disease in the Lymph Nodes of Free-Ranging Cervids by Real-Time Quaking-Induced Conversion

Chronic wasting disease (CWD), a transmissible spongiform encephalopathy of deer, elk, and moose, is the only prion disease affecting free-ranging animals. Since the disease was first identified in northern Colorado and southern Wyoming in 1967, new epidemic foci of the disease have been identified in 20 additional states, as well as two Canadian provinces and the Republic of South Korea. Identification of CWD-affected animals currently requires postmortem analysis of brain or lymphoid tissues using immunohistochemistry (IHC) or an enzyme-linked immunosorbent assay (ELISA), with no practical way to evaluate potential strain types or to investigate the epidemiology of existing or novel foci of disease. Using a standardized real-time (RT)-quaking-induced conversion (QuIC) assay, a seeded amplification assay employing recombinant prion protein as a conversion substrate and thioflavin T (ThT) as an amyloid-binding fluorophore, we analyzed, in a blinded manner, 1,243 retropharyngeal lymph node samples from white-tailed deer, mule deer, and moose, collected in the field from areas with current or historic CWD endemicity. RT-QuIC results were then compared with those obtained by conventional IHC and ELISA, and amplification metrics using ThT and thioflavin S were examined in relation to the clinical history of the sampled deer. The results indicate that RT-QuIC is useful for both identifying CWD-infected animals and facilitating epidemiological studies in areas in which CWD is endemic or not endemic.