Multiplex PCR protocol for the diagnosis of staphylococcal infection.

We report the development of a multiplex PCR protocol for the diagnosis of staphylococcal infection. The protocol was designed to (i) detect any staphylococcal species to the exclusion of other bacterial pathogens (based on primers corresponding to Staphylococcus-specific regions of the 16S rRNA genes), (ii) distinguish between S. aureus and the coagulase-negative staphylococci (CNS) (based on amplification of the S. aureus-specific clfA gene), and (iii) provide an indication of the likelihood that the staphylococci present in the specimen are resistant to oxacillin (based on amplification of the mecA gene). The expected fragments were amplified from each of 60 staphylococcal isolates (13 oxacillin-resistant S. aureus isolates, 23 oxacillin-sensitive S. aureus isolates, 17 oxacillin-resistant CNS, and 7 oxacillin-sensitive CNS). No amplification products were observed with template DNA from nonstaphylococcal species, and the efficiency of amplification of staphylococcal targets was not adversely affected by the presence of DNA from other bacterial species in the same sample. The utility of the protocol for the analysis of clinical samples was verified by analysis of aliquots taken directly from BacT/Alert blood culture bottles. Of 77 blood cultures tested, only 7 yielded results inconsistent with those of conventional methods of diagnosis and susceptibility testing. Of those, one was identified as a CNS species by PCR and S. aureus by conventional methods. We also identified two isolates that were mecA positive but were oxacillin sensitive according to conventional methods. The other four samples failed to yield any amplification product even with a control set of primers corresponding to a conserved region of the eubacterial rRNA genes.

Sleep estimation from wrist movement quantified by different actigraphic modalities.

Progress in transducer design and empirical characterization of wrist movement has led to diverse wrist activity monitors, each with its unique features and modality of operation. This study compared sleep--wake estimates from nocturnal wrist activity quantified by different motion-quantifying algorithms. Healthy young adults wore an Actillume and a Mini Motionlogger on the same wrist while nocturnal polysomnography data were recorded simultaneously in the laboratory. Activity data were analyzed with ACTION3 using scoring algorithms independently calibrated for each measurement modality. Overall, each modality yielded accurate and reliable sleep estimates relative to polysomnographic estimates (agreement rates: 91.4--96.5%, correlations for sleep duration: 0.79--0.94). Estimates derived from Actillume modalities were comparable to those of Mini Motionloggers, suggesting that the transducers of these two devices performed comparably for monitoring sleep and wakefulness. Wrist movement quantified by the Mini Motionlogger proportional-integrating mode yielded the best accuracy for detection of sleep--wake states.

Periodic leg movements during sleep and sleep disturbances in elders.

BACKGROUND: Periodic limb movements in sleep (PLMS) are an increasingly pervasive disturbance for aging adults. The aims of this experiment were: (a) to describe the index of periodic limb movements in sleep (myoclonus index [MI] in elderly subjects with complaints of poor sleep or depression (N = 22; 68 +/- 5.5 SD years); and (b) to correlate MI with sleep history, depression scores, and objective and subjective indices of sleep. METHOD: Sleep and leg movements were assessed for 5 consecutive nights. Between-subjects, nonparametric correlations were examined between mean MI and sleep history, depression scores, and objective and subjective sleep characteristics. Associations among within-subject night-to-night variabilities of MI, objective, and subjective variables were examined with repeated measures ANCOVA, entering MI as a covariate. RESULTS: A remarkably high level of MI was found (median 25.8 events per hour; 86% of subjects > 5). Nevertheless, no associations were found between MI and sleep disturbance measures. CONCLUSION: These results extend previous reports that PLMS are remarkably persuasive in elderly volunteers and support other reports questioning whether there is a distinct PLMS syndrome.

Prevalence of sleep-disordered breathing in ages 40-64 years: a population-based survey.

Previous research has offered widely varying prevalence estimates for sleep apnea in the population, leaving uncertain which breathing patterns are abnormal. To explore the distribution of sleep apnea in the population and its co-morbidities, random telephone dialing was used between 1990 and 1994 to recruit subjects for a prevalence survey of sleep-disordered breathing in San Diego adults. Events from which blood oxygen desaturations > or = 4% resulted were monitored with home recording instruments, usually for three consecutive nights. Among 190 women ages 40-64 years, a median of 4.3 desaturation events per hour of sleep were observed. A higher median of 6.7 events per hour was observed among 165 men. Frequencies were much higher among members of minority groups, leading to a standard estimate that 16.3% of U.S. Hispanics and racial minorities have > or = 20 events/hour as compared to 4.9% of non-Hispanic Whites ages 40-64. Obesity indicated by body-mass index was the most important demographic predictor of sleep-disordered breathing, followed by age, male gender, and ethnicity. Quality of well-being was not significantly impaired in subjects with more respiratory events; however, there was some increase in blood pressure and wake-within-sleep associated with sleep-disordered breathing. This survey indicates that sleep-disordered breathing is more common, especially among minorities, than had been previously believed, but less co-morbidity may be associated.

Seasonal variation in human illumination exposure at two different latitudes.

The authors measured ambient illumination exposure in healthy volunteers in San Diego, California (latitude 32 degrees 43' N, n = 30), and Rochester, Minnesota (latitude 44 degrees 1' N, n = 24), during each of the four quarters of the year, which were centered on the solstices and equinoxes. Subjects wore photosensors on their wrists and lapels (or foreheads while in bed) 24 h per day for an average of 5-6 days per quarter. The maximum of the two illumination readings was stored each minute. Annual average time spent per day in outdoor illumination (> or = 1000 lux) was significantly higher in San Diego than it was in Rochester (p < .04). Daily durations of illumination at or exceeding thresholds of 1, 10, 100, 1000, and 10,000 lux were highly seasonal in the sample as a whole (p < .01 at 1 lux, p < .0001 at other thresholds). Seasonal variation in outdoor illumination was far more pronounced in Rochester than it was in San Diego (interaction p < .001) but remained significant in San Diego (p < or = .03). Seasonal variation in indoor illumination was generally similar in the two cities. The median Rochester subject experienced illumination > or = 1000 lux for 2 h 23 min per day during summer and 23 min per day during winter. The corresponding times in San Diego were 2 h 10 min and 1 h 20 min. Neither age nor gender predicted illumination duration at any level. Both season and geographic location strongly influenced human illumination exposure, and behavior (choice of indoor vs. outdoor environment) was the most important mediating factor.

Low illumination experienced by San Diego adults: association with atypical depressive symptoms.

We explored the illumination exposure of middle-aged adults to determine normal values and to explore several correlates of daily light exposures. Subjects aged 40-64 years in San Diego, CA were recruited by random telephone dialing. Subjects completed a demographic interview and the Center for Epidemiologic Studies Depression self-rating scale (the CES-D) supplemented with eight questions related to seasonal affective disorders (SAD). Data were analyzed for 106 volunteers who wore a device that monitors illumination exposures and activity. The median subject was exposed to illumination > or = 1000 lux for only 4% of the time observed, that is, only about 58 min per day were spent in daylight. Subjects scoring higher on the atypical SAD mood symptoms spent less time in bright illumination rs = -0.266, p = 0.003. The CES-D depression score was similarly correlated with illumination but of borderline significance (rs = -0.150, p = 0.063). These results suggest the hypothesis that many Americans may be receiving insufficient light exposure to maintain optimal mood.

Periodic limb movements in sleep in community-dwelling elderly.

The prevalence of periodic limb movements in sleep (PLMS) in a randomly selected elderly sample is reported. In San Diego, 427 elderly volunteers aged 65 yr and over were recorded in their homes. Forty-five percent had a myoclonus index, MI greater than or equal to 5. Correlates of PLMS included dissatisfaction with sleep, sleeping alone and reported kicking at night. Although statistically significant, the strengths of the associations between interview variables and myoclonus indices were all small. No combination of demographic variables and symptoms allowed highly reliable prediction of PLMS.

Sleep-disordered breathing in community-dwelling elderly.

These are the final results of a survey of sleep-disordered breathing, which examined objective and subjective information from a large randomly selected elderly sample. We randomly selected 427 elderly people aged 65 yr and over in the city of San Diego, California. Twenty-four percent had an apnea index, AI, greater than or equal to 5 and 62% had a respiratory disturbance index, RDI, greater than or equal to 10. Correlates of sleep-disordered breathing included high relative weight and reports of snoring, breathing cessation at night, nocturnal wandering or confusion, daytime sleepiness and depression. Body mass index, falling asleep at inappropriate times, male gender, no alcohol within 2 hr of bedtime and napping were the best predictors of sleep-disordered breathing. Despite statistical significance, all of the associations between interview variables and apnea indices were small. No combination of demographic variables and symptoms allowed highly reliable prediction of AI or RDI.

Apnea revisited: a longitudinal follow-up.

Volunteers aged 65 years and over who were previously studied underwent follow-up interviews and sleep recordings several years later (mean follow-up, 4.6 years). Modest correlations between the initial and subsequent recordings were found for apnea index, hypopnea index, and respiratory disturbance index. Sleep apnea indices did not increase over time; however, individual subjects showed great variability in amount of apnea. Periodic leg movement indices, on the other hand, significantly increased. Subjective reports indicated a significant increase in the amount of time spent awake and a significant decrease in the amount of loud snoring.

Assessment of quadriceps/hamstring strength, knee ligament stability, functional and sports activity levels five years after anterior cruciate ligament reconstruction.

The purpose of this study was to examine individuals 5 years after ACL reconstruction and analyze changes involving strength, stability, function, and sports activities. Nineteen males and six females, mean age = 31.4 +/- 7.31 years, participated in this study. Fifteen subjects had received extraarticular and ten subjects had received intraarticular ACL reconstructions. Subjects completed a 100 point subjective functional activity questionnaire and a sports participation survey. Knee ligament stability was assessed during an objective knee examination. Isokinetic quadriceps and hamstring muscle strength were tested at 240 and 120 deg/sec using the Cybex II dynamometer. Anterolateral rotatory instability and positive Lachman were elicited on the operated leg for 80% of the subjects. No significant relationship was found between objective instability and the functional activity score. For the intraarticular group, a significant correlation (P less than 0.05) was found between increased quadriceps and hamstring strength on the operated leg and return to functional activities. Subjects' functional activity score was positively correlated (P less than 0.001) with their ability to participate in sports. Subjects participating in sports involving cutting and twisting motions were less successful in returning to their preinjury participation levels and reported more subjective complaints of pain, swelling, and/or instability. These results indicate that long-term progressive rehabilitation emphasizing increased quadriceps and hamstring strength to approximate the nonoperated leg may enhance successful return to functional and sports activities after ACL reconstruction.