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PubMed1979

[Problems of rehabilitating patients who have undergone a mitral commissurotomy].

The article analyses the course of the rheumatic process in 241 patients who underwent mitral commissurotomy. Study was conducted at the same time of the volume of antirecurrence antirheumatic treatment applied before and after operation and its importance in the prevention of exacerbations of rheumatism in late postoperative periods. Analysis was made of the working capacity of 241 patients in follow-up periods of one to 20 years after operation and the individual tolerance to physical exertion was determined in 52 patients. It was found that the maximum number of individuals in occupation (62.3%) is encountered in the period from 5 to 11--12 years.

Follow-Up Studies↗
PubMed1999

Observations on labor epidural analgesia and operative delivery rates.

OBJECTIVE: Our purpose was to compare operative vaginal and abdominal delivery rates in a large population before and after on-demand labor epidural analgesia became available. STUDY DESIGN: We retrospectively compared patients who gave birth during a 20-month period immediately before the introduction of an on-demand labor epidural analgesia service with those who gave birth during a 20-month period after the epidural usage rate had reached a plateau at approximately 60%. Operative vaginal and cesarean delivery rates were stratified according to parity and history of prior cesarean delivery. RESULTS: A total of 4859 women gave birth during the study period when on-demand epidural analgesia was available, and 4778 women gave birth in the study period before the availability of on-demand epidural analgesia. Comparisons between the women with and those without on-demand availability of epidural analgesia demonstrated no statistically significant differences in the rate of spontaneous vaginal delivery (69.5% vs 68.3%), the overall cesarean delivery rate (19.0% vs 19.4%), the primary cesarean delivery rate (13.2% vs 13.4%), or the operative vaginal delivery rate (11.1% vs 11.9%) between the 2 periods. There were no statistically significant differences in mean gestational age at the time of delivery between the 2 groups, whereas there were statistically significant increases in the proportion of nulliparous women and in mean birth weight during the on-demand epidural period. Analysis after substratification of the study groups according to parity also revealed no statistically significant differences in the primary cesarean delivery rate or the proportion of women undergoing vaginal delivery. The sample size was adequate to exclude a 2% increase in the primary cesarean delivery rate between the 2 periods with 80% power. Subgroup analysis of the population of women who gave birth while epidural analgesia was available on request demonstrated that nulliparous parturient women who requested epidural analgesia were almost twice as likely to require operative vaginal or cesarean delivery as women who did not request epidural analgesia, a finding suggesting that women who request labor epidural analgesia have an inherent propensity toward operative delivery. CONCLUSION: The introduction of an on-demand labor epidural analgesia service does not increase the rate of cesarean delivery or operative vaginal delivery.

Adult↗
PubMed1993

Laboratory instrumentation and computing: comparison of six methods for the determination of the period of circadian rhythms.

Data sets with known periodicity were used to compare the accuracy and noise tolerance of six methods of circadian period analysis: Fourier analysis, autocorrelation, Enright's (chi-square) periodogram, linear regression of onsets, interonset averaging, and acrophase counting. All methods except acrophase counting accurately detected the period of rhythms with pure waveform (cosine and square wave), whereas Fourier analysis and Enright's periodogram were superior to the other methods in the analysis of more complex waveforms (which more closely resemble actual circadian rhythms). The sensitivity of all methods was reduced by the insertion of random noise into the original data sets, but the methods of autocorrelation and Enright's periodogram were more tolerant of low signal-to-noise ratios than the remaining methods. Although particular situations may require particular methods, the results suggest that Enright's periodogram is the best choice as a general method for the determination of the period of circadian rhythms.

Animals↗
PubMed1992

Advance shift of feeding circadian rhythm induced by obesity progression in Zucker rats.

To determine the relation between the circadian rhythm of ingestive behavior and the progression of obesity in Zucker rats, ingestion and ambulation were analyzed at four different developmental stages. The obese rats were disrupted gradually in nocturnal patterns of feeding, drinking, and ambulation with the progression of obesity, although the lean littermates maintained the patterns during whole test periods. Analysis of autocorrelogram revealed that circadian rhythms of those behaviors remained throughout the whole test periods. Least-squares spectrum ascertained the following. 1) The obese made advance shift of acrophases in feeding and drinking circadian cycles, but not in ambulation. 2) Amplitudes in those behavioral measures decreased with the progression of obesity. 3) Mesor in the obese feeding was not affected, although that in the lean feeding decreased. The findings indicate that disruption of the light-dark cycle in ingestion of the obese was not due to disappearance of circadian rhythm but to transformation by both decreased amplitude and advance shift of the circadian cycle.

Animals↗
PubMed1979

Nocturnal vs diurnal cardiac arrhythmias in patients with chronic obstructive pulmonary disease.

Continuous electrocardiograms were recorded from ten patients with chronic obstructive pulmonary disease. During 24 hours of recording, the patients breathed air; and for 24 hours, they breathed oxygen at 2 L/min by nasal cannula. Oxygenation, as monitored by ear oximetric studies and by periodic analysis of arterial blood, showed frequent nocturnal desaturation. Nine patients demonstrated arrhythmias during the monitoring period, and the frequency of premature ventricular contractions was significantly greater at night. Therapy with supplemental oxygen dramatically reduced the frequency of premature ventricular contractions in four patients, but the reduction in frequency of arrhythmias in the total group did not reach statistical significance. These results show that cardiac arrhythmias occur commonly at night during sleep in patients with chronic obstructive pulmonary disease. The data suggest that arterial desaturation may be responsible for some of these arrhythmias.

Aged↗
PubMed2002

[Simulation of N2O emissions in agroecosystems].

A numerical model for simulating N2O emissions in agroecosystem was established. Validation of the model with the observed data showed that the model simulated the process of N2O emissions in fields fairly well. The numerical analysis showed that the N2O emissions were interrelated well with average temperature during rice growth periods. Analysis of N2O emissions and meteorological factors by using power spectrum found that the change of N2O emissions had 7-9 year cycles. Sensitivity test showed that the N2O emission increased with temperature enhancement.

Air Pollution↗
PubMed1989

[The effect of sufentanil in high doses on hemodynamics and electroencephalography activity in coronary patients].

Sufentanil, a synthetic opioid that is 5-10 times as potent as fentanyl, has been suggested by some authors to prevent hypertensive responses to noxious stimuli in patients undergoing coronary artery bypass surgery much better than fentanyl, while in other studies it has failed to maintain cardiovascular stability during surgical stimulation. This study was designed to investigate the cardiovascular and electroencephalographic effects of high-dose sufentanil/O2/pancuronium anesthesia in patients undergoing coronary artery bypass surgery. METHODS. Two different doses of sufentanil were administered to two groups including a total of 20 male patients. Patients in group 1 (n = 10) received 10 micrograms.kg-1 sufentanil as an induction dose plus 0.15 microgram.kg-1.min-1 as a continuous infusion, while 10 micrograms.kg-1 plus 0.3 microgram.kg-1.min-1 were administered to the patients in group 2 (n = 10). Hemodynamic measurements were performed with the patients awake (I), 15 min following the induction of anesthesia with sufentanil and pancuronium at rest (II), and during sternotomy and sternal spreading (III). Patients were ventilated with oxygen in air (FiO2 = 0.5). Cerebral electrical activity was recorded by periodic analysis of the EEG, and plasma concentrations of sufentanil were measured throughout the entire study period. RESULTS AND DISCUSSION. The dosage scheme used in this study, which consisted of a sufentanil bolus followed by a continuous infusion, prevented plasma concentrations of sufentanil from declining in both groups during the entire study period. Following induction there was a significant decrease in systolic arterial pressure by 12% in group 1 and 20% in group 2 accompanied by a reduction in cardiac index by 25% and 21%, respectively, and in stroke volume index by 19% in group 1 and 24% in group 2, while systemic vascular resistance increased by 27% and 10%, respectively. Sternotomy led to a rise in systolic arterial pressure that did not exceed the awake values in both groups, while diastolic and mean arterial pressures (MAP) increased by 17% and 14% and by 15%, respectively, due to further increases in systemic vascular resistance by 57% and 41% above the control values. Cardiac and stroke volume indexes stayed significantly lower than the awake values, whereas heart rate remained essentially unchanged during the course of the study. There were no statistically significant differences between the groups during all measurements. In the EEG, sufentanil anesthesia was characterized by a decrease in the number of higher frequency waves and an increase in lower frequency (delta) waves, which did not change during sternotomy in 17 of the 20 patients.

Adult↗
PubMed2000

Structural analysis of DNA sequence: evidence for lateral gene transfer in Thermotoga maritima.

The recently published complete DNA sequence of the bacterium Thermotoga maritima provides evidence, based on protein sequence conservation, for lateral gene transfer between Archaea and Bacteria. We introduce a new method of periodicity analysis of DNA sequences, based on structural parameters, which brings independent evidence for the lateral gene transfer in the genome of T.maritima. The structural analysis relates the Archaea-like DNA sequences to the genome of Pyrococcus horikoshii. Analysis of 24 complete genomic DNA sequences shows different periodicity patterns for organisms of different origin. The typical genomic periodicity for Bacteria is 11 bp whilst it is 10 bp for Archaea. Eukaryotes have more complex spectra but the dominant period in the yeast Saccharomyces cerevisiae is 10.2 bp. These periodicities are most likely reflective of differences in chromatin structure.

Chromatin↗
PubMed1991

Electroencephalographic sleep in the healthy "old old": a comparison with the "young old" in visually scored and automated measures.

This report extends the normative study of sleep into healthy 80-year-olds and compares them with healthy 70- and 60-year-olds. We observed stability of sleep efficiency and rapid eye movement sleep across three decades of late life, but a slight decline of slow-wave sleep in the 80-year-olds (decreased total delta wave counts). Women showed better preservation of slow-wave sleep than men. Automated EEG period analysis of this phenomenon demonstrated higher rates of delta wave production in the first NREM sleep period of women compared to that of men, a finding associated with longer REM sleep latencies in women. Unexpectedly, 80-year-old women showed decay in sleep maintenance, while 80-year-old men demonstrated stability of sleep maintenance, relative to their respective 60- and 70-year-old counterparts. Implications for the understanding of sleep and its regulation in health and aging are discussed.

Aged↗
PubMed2001

Effect of storage temperature on endogenous GHB levels in urine.

Because gamma-hydroxybutyrate (GHB) is an endogenous substance present in the body and is rapidly eliminated after ingestion, toxicologists investigating drug-facilitated sexual assault cases are often asked to differentiate between endogenous and exogenous levels of GHB in urine samples. This study was designed to determine the effects of storage temperature on endogenous GHB levels in urine. Specifically, it was designed to ascertain whether endogenous levels can be elevated to a range considered indicative of GHB ingestion. Urine specimens from two subjects that had not been administered exogenous GHB were collected during a 24h period and individually pooled. The pooled specimens were separated into standard sample cups and divided into three storage groups: room temperature ( approximately 25 degrees C), refrigerated (5 degrees C), and frozen (-10 degrees C). Additionally, some specimens were put through numerous freeze/thaw cycles to mimic situations that may occur if multiple laboratories analyze the same specimen. Periodic analysis of the samples revealed increases in the levels of endogenous GHB over a 6-month period. The greatest increase (up to 404%) was observed in the samples maintained at room temperature. The refrigerated specimens showed increases of 140-208%, while the frozen specimens showed smaller changes (88-116%). The specimens subjected to multiple freeze/thaw cycles mirrored specimens that had been thawed only once. None of the stored urine specimens demonstrated increases in GHB concentrations that would be consistent with exogenous GHB ingestion.

Bias↗
PubMed1999

Determination of residues of the plant growth regulator chlormequat in pears by ion-exchange high performance liquid chromatography-electrospray mass spectrometry.

We report a method which we have used routinely for the determination of chlormequat residues in pears. After extraction with methanol, determination was performed, without clean-up, by ion-exchange HPLC using an SCX column eluted with aqueous ammonium formate-methanol, and HPLC-MS with an electrospray interface. MS and MS-MS were employed concurrently, using selected ion monitoring and selected reaction monitoring, respectively, of the 35Cl and 37Cl isotopes of the chlormequat cation and the CID transitions of each of these precursors to the common product ion at m/z 58. The method was suitable for determinations at concentrations of chlormequat cation of 0.04 mg kg-1. Concentrations determined using the four signals were in good agreement (mean RSD 3%). The mean recovery of chlormequat cation at 0.16 mg kg-1, measured using the m/z 122-->58 signal, was 86% (RSD 7%) under repeatability conditions and 88% (RSD 15%) in routine application of the method over a 3 month period. Analysis of an in-house reference sample of pears, similarly analysed over the 3 month period, gave an RSD of 10% with a mean of 0.14 mg kg-1. Mean recovery at 0.016 mg kg-1, under repeatability conditions on two occasions, was 101% (RSD 6%) and 56% (RSD 12%).

Chlormequat↗
PubMed2004

Effect of danofloxacin and tilmicosin on body temperatures of beef calves with pneumonia experimentally induced by inoculation with Mannheimia haemolytica.

OBJECTIVE: To examine effects of danofloxacin and tilmicosin on continuously recorded body temperature in beef calves with pneumonia experimentally induced by inoculation of Mannheimia haemolytica. ANIMALS: 41 Angus-cross heifers (body weight, 160 to 220 kg) without a recent history of respiratory tract disease or antimicrobial treatment, all from a single ranch. PROCEDURE: Radiotransmitters were implanted intravaginally in each calf. Pneumonia was induced intrabronchially by use of logarithmic-phase cultures of M. haemolytica. At 21 hours after inoculation, calves were treated with saline (0.9% NaCl) solution, danofloxacin, or tilmicosin. Body temperature was monitored from 66 hours before inoculation until 72 hours after treatment. Area under the curve (AUC) of the temperature-time plot and mean temperature were calculated for 3-hour intervals and compared among treatment groups. RESULTS: The AUCs for 3-hour intervals did not differ significantly among treatment groups for any of the time periods. Analysis of the mean temperature for 3-hour intervals revealed significantly higher temperatures at most time periods for saline-treated calves, compared with temperatures for antimicrobial-treated calves; however, we did not detect significant differences between the danofloxacin- and tilmicosin-treated calves. The circadian rhythm of temperatures before exposure was detected again approximately 48 hours after bacterial inoculation. CONCLUSIONS AND CLINICAL RELEVANCE: Danofloxacin and tilmicosin did not differ in their effect on mean body temperature for 3-hour intervals but significantly decreased body temperature, compared with body temperature in saline-treated calves. Normal daily variation in body temperature must be considered in the face of respiratory tract disease during clinical evaluation of feedlot cattle.

Animals↗
PubMed1998

Power spectral analysis of heart period variability of preceding sinus rhythm before initiation of paroxysmal atrial fibrillation.

Time domain analysis of heart period variability in patients without structural heart disease demonstrated increased parasympathetic modulation before paroxysmal atrial fibrillation (AF) occurring predominantly at night. However, diurnal differences in autonomic activity preceding AF episodes in a diverse patient population have not been assessed. Accordingly, we performed spectral analysis of heart period variability on Holter recordings during sinus rhythm preceding AF in 29 patients, 17 with night and 12 with day episodes. Samples taken 5, 10, and 20 minutes before AF onset were compared. Normalized high-frequency (HF) spectral power change was greater when comparing the interval 10 to 5 minutes with 20 to 10 minutes preceding AF in 26 of 29 patients (0.09 +/- 0.07 vs 0.03 +/- 0.02; p < 0.0001). HF spectral power increased before 3 of 12 AF episodes during the day compared with 15 of 17 AF episodes during the night (p = 0.001). Nocturnal AF episodes were preceded by increased HF spectral power in the 5- versus the 20-minute sample expressed as natural logarithm-transformed values (5.6 +/- 4.8 vs 4.2 +/- 4.0; p < 0.005) and normalized values (0.19 +/- 0.09 vs 0.10 +/- 0.07; p < 0.02), a decrease in low-frequency/HF ratio (1.05 +/- 0.61 vs 2.21 +/- 1.75; p < 0.05) and heart rate (60 +/- 13 vs 71 +/- 13 beats/min; p = 0.06). Structural heart disease was more common with daytime than nocturnal AF episodes (58% vs 18%, p < 0.05). In conclusion, HF spectral power change was increased preceding most AF episodes. However, diurnal differences were demonstrated. Contrary to daytime AF, increased parasympathetic activity preceded predominantly nocturnal AF, mostly in younger patients with structurally normal hearts.

Aged↗
PubMed2003

Effect of S6 tail mutations on charge movement in Shaker potassium channels.

The cytoplasmic ends of the four S6 transmembrane segments of voltage-gated potassium channels converge in a bundle crossing that acts as the activation gate that opens in response to a depolarization. To explore whether the cytoplasmic extension of the S6 segment (the S6 tail) plays a role in coupling voltage sensor and activation gate movements, we examined the effect of cysteine substitution from residues N482 to T489 on the kinetics and voltage-dependence of S4 charge movement and on the kinetics of deactivation of ionic current. Among these mutants, F484C has the steepest voltage-dependent charge movement, the largest Q-V shift, and the fastest OFF gating currents. Further study of the residue at position 484, using mutagenesis and modification of F484C by cysteine reagents, suggests that aromaticity at this position is essential to maintain normal coupling. We used periodicity analysis to appraise the possibility that the S6 tail has an alpha-helical structure. Although we obtained an alpha-periodicity index of 2.41 for gating current parameters, a new randomization test produced an indecisive conclusion about the secondary structure of this region. Taken together, our results suggest that the tail end of S6 plays an important role in coupling between activation gating and charge movement.

Cell Membrane Permeability↗
PubMed2001

Ether: stability in preserved blood samples and a case of ether-assisted suicide.

Ethyl ether was detected in the blood of a deceased individual who had inhaled it from a mask while hanging himself. This case led to an investigation into the stability of ether in stored blood samples as described herein. Ether was spiked, at three concentrations, into batches of porcine blood. The blood was apportioned into grey-stoppered collection tubes and stored refrigerated until analysis. The concentration of ether in the blood was assessed at intervals over a two-month period. Analysis was performed by headspace gas chromatography. This study has shown, for a concentration range of 0.1 to 5.0 mg/mL, ether is stable in preserved, refrigerated blood for at least two months.

Administration, Inhalation↗
PubMed1997

Hawthorne effect: shortening of fluoroscopy times during radiation measurement studies.

Screening times were recorded before (n = 92, 13 radiologists) and after (n = 75, 6 radiologists) commencing a protocol with dose-area product (DAP) measurements and filling of structured questionnaires. Fluoroscopy times were significantly (p = 0.0001) longer before starting these measurements (median 4.3, mean 5.2 min) than during them (median 3.2, mean 3.6 min), which indicates a Hawthorne effect. Fluoroscopy times did not increase during the DAP measurement period up to 21 barium enemas and a study period of up to 45 days per radiologist. Previous fluoroscopic radiation measurements based on action during an analysis period may be biased towards too short fluoroscopy times and too low doses. Radiation measurement, even if not scientifically indicated, seems a practical way of reducing doses.

Barium Sulfate↗
PubMed1990

A double-blind study of the effectiveness of a high-efficiency particulate air (HEPA) filter in the treatment of patients with perennial allergic rhinitis and asthma.

This study was designed to assess the effectiveness of a high-efficiency particulate air (HEPA) filter in alleviating allergic respiratory symptoms. Thirty-two patients were studied who had symptomatic perennial rhinitis and/or asthma during the fall and winter months and had a positive skin test with house dust or house dust--mite extract. An ENVIRACAIRE room air cleaner was placed in the bedroom for 8 weeks. In a random manner, the active filter was used for 4 weeks and a blank filter for 4 weeks. There was an average 70% reduction in the particulate matter greater than or equal to 0.3 micron with the HEPA filter. In a double-blind design, results were assessed by analysis of the patients' symptom/medication scores and subjective evaluation. For the total study, there was no difference in the total symptom/medication scores or individual symptom scores during the placebo and active-filter periods. Analysis of the last 2 weeks of each filter period in which respiratory infection was absent demonstrated definite differences in total and individual symptoms, suggesting active-filter benefit. Patients' subjective responses also suggested benefit from the filter. The overall impression is that the HEPA filter can reduce allergic respiratory symptoms.

Adolescent↗
PubMed1997

Methadone maintenance and drug-related crime.

Using data from an evaluation of methadone maintenance treatment, this study investigated factors associated with continued involvement in crime during treatment, and in particular whether there appeared to be differences in effectiveness of treatment between different methadone clinics. The methodology was an observational study, in which 304 patients attending three low-intervention, private methadone clinics in Sydney were interviewed on three occasions over a twelve month period. Outcome measures were self-reported criminal activity and police department records of convictions. By self-report, crime dropped promptly and substantially on entry to treatment, to a level of acquisitive crime about one-eighth that reported during the last addiction period. Analysis of official records indicated that rates of acquisitive convictions were significantly lower in the in-treatment period compared to prior to entry to treatment, corroborating the changes suggested by self-report. Persisting involvement in crime in treatment was predicted by two factors: the cost of persisting use of illicit drugs, particularly cannabis, and ASPD symptom count. Treatment factors also were independently predictive of continued involvement in crime. By both self-report and official records, and adjusting for subject factors, treatment at one clinic was associated with greater involvement in crime. This clinic operated in a chaotic and poorly organized way. It is concluded that crime during methadone treatment is substantially lower than during street addiction, although the extent of reduction depends on the quality of treatment being delivered.

Adult↗