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Biomedical subjects

R Epstein

Publications and source records attributed to R Epstein.

162 records · Page 9Linked to original sources
PubMedDate not supplied

Do heated humidifiers and heat and moisture exchangers prevent temperature drop during lower abdominal surgery?

STUDY OBJECTIVE: To compare the effects of using a heated humidifier (HH), a heat and moisture exchanger (HME), or no warming device in maintaining body temperature during surgical procedures of 1 to 4 hours' duration. DESIGN: A randomized, controlled study. SETTING: Operating room, Thomas Jefferson University Hospital, Philadelphia, PA. PATIENTS: 51 ASA physical status I, II, and III patients, age 16 to 69 years, scheduled for a variety of lower abdominal procedures under general endotracheal anesthesia anticipated to last 1 to 4 hours. INTERVENTIONS: We randomly assigned patients to receiving an HH, an HME, or no warming device during the procedure. We then measured the patient's sublingual temperature every 5 minutes prior to induction, every 15 minutes intraoperatively, and every 15 minutes postoperatively until he or she was discharged from the postanesthesia care unit, (PACU). We also measured the esophageal temperature every 15 minutes intraoperatively. MEASUREMENTS AND MAIN RESULTS: Sublingual temperature or esophageal temperature probes placed at the site of maximal heart tones indicated that the patients' temperatures dropped significantly from baseline values in all three groups during the first 60 minutes of surgery, then remained constant during the next 120 minutes of surgery. Patients who had no warming device shivered and felt cold significantly more often than patients in the HH group but not more often than patients in the HME group. There was no difference in shivering between the HH and HME groups. The patients who received an HH tended to have a higher temperature (a mean of 0.5 degrees C) throughout the study, but this did not reach statistical significance. CONCLUSIONS: Results indicate that these warming devices provide little benefit in preventing a temperature drop during procedures of 1 to 4 hours' duration, although patients with an HH tended to have a higher temperature than those with an HME or no device.

Abdomen↗
PubMedDate not supplied

'Insight' in the pigeon: antecedents and determinants of an intelligent performance.

In 1917 Wolfgang Köhler reported some rather extraordinary instances of problem solving by a number of chimpanzees, and his observations have been the subject of controversy ever since. The period of quiescence that sometimes preceded the solution, its sudden onset, and its smooth, continuous emergence were proffered as evidence that (1) contrary to suggestions of learning theorists of the day, problem solving was not necessarily a trial-and-error process, and (2) constructs such as 'insight' were necessary for an adequate account. Here, in an attempt to shed further light on these issues, we have replicated with pigeons a classic problem with that Köhler confronted his chimpanzees. Pigeons that had acquired relevant skills solved the problem in a remarkably chimpanzee-like (and, perforce, human-like) fashion. The possible contributions of different experiences were determined by varying the training histories of different birds. We offer a tentative moment-to-moment account of a successful performance.

Animals↗
PubMedDate not supplied

Brain potentials from dyslexic children recorded during short-term memory tasks.

Event Related Potentials (ERPs) from thirty children (9-13 years old); fourteen of whom were dyslexic and sixteen normal-reading controls, were recorded during the performance of a memory scanning task. Visually presented stimuli consisted of either digits (lexical) or unfamiliar (non-lexical) characters. The subjects had to indicate whether a probe stimulus was a member of a preceding memorized set, or not. The memorized sets included 1, 2 or 3 items. Performance accuracies were significantly lower and reaction times longer in the dyslexic group. The significant Group x Lexicality interaction demonstrated P3 amplitudes which were smaller to lexical compared to non-lexical stimuli in dyslexics compared to skilled readers. Brain activity in response to the probes was more prominent over the right scalp in dyslexics, in contrast to controls that had left side prominence. The results suggest that dyslexic children relate to the physical features of stimuli as opposed to skilled readers, who rely more on the linguistic features of the stimuli. We suggest that remembering visually presented items in dyslexics involves different cognitive strategies and brain structures compared to skilled readers.

Adolescent↗
PubMedDate not supplied

Effect of time interval between ejaculations on semen parameters.

The suggested abstinence period prior to performing a semen analysis has been 2-5 days. If one allows too long of an interval between ejaculates, motility will decrease significantly. This study was designed to evaluate whether any of the semen parameters change with increasing intervals of time between ejaculates and, if so, what parameters are involved. A derived calculation total-live sperm count (product of count/milliliter x volume x percent motility) was significantly lower at 3 days than at 7-, 10-, and 14-day intervals. Sperm count and motility showed a significant decrease at 14 days as compared to 7 days but not to 3 days. There were no significant differences between motility, the hypoosmotic swelling test, velocity, linearity, motile density, or morphology (with strict criteria). The ideal abstinence interval is between 7 and 10 days not 2-3 days, and motility does not appear to significantly decrease with a long interval between ejaculates.

Analysis of Variance↗
PubMedDate not supplied

Late luteal phase progestogen-dependent endometrial protein levels in women with in-phase biopsies--can low levels predict a subfertile group?

A group of infertile women who had luteal phase defects (LPD), but in whom follicular maturation was deemed normal, were treated with progesterone until the endometrial biopsy was corrected. At the time the corrected biopsy was obtained, serum was taken and the progestogen-dependent endometrial protein (PEP) concentration was determined. Serum PEP concentration in patients who successfully conceived was 102.5 +/- 62.6% units/mL, while PEP concentrations in patients who failed to conceive were 57.9 +/- 34.4% (P = .003). In patients whose PEP value was more than two standard deviations below the corresponding mean control PEP, pregnancy was achieved in 6/17 (35.3%). The conception rate was significantly greater (25/35, 71.4%) in patients with values higher than this. Thus, the PEP concentration in serum may identify a group of patients with persistent LPD despite apparent normalization of the morphology of late secretory phase endometrium, which might explain some cases of cryptic, unexplained infertility.

Biopsy↗
PubMedDate not supplied

Sleep-wake cycle in shift workers on a "clockwise" and "counter-clockwise" rotation system.

The present study investigated the effects of a 5-day rotating work schedule in the advance, or "counter-clockwise", vs. delay, or "clockwise" direction, on subjective and objective measures of sleep-wake cycles. Twenty-two workers (mean age 27.5 +/- 4.6 years) were studied in the counter-clockwise direction, and 11 workers (mean age 29.83 +/- 5.93) were studied in the clockwise direction. Each worker was studied for a complete rotation cycle (20 days). Sleep-wake cycles were measured by wrist-worn actigraphs in 1-min bins. The clockwise direction was associated with significantly earlier sleep times during the night shift, and with a better synchronization of workers' sleep-wake cycles during night and evening shifts. The present results provide support to the claim that rotating shiftworkers can better adapt to clockwise than counter-clockwise rotations.

Adaptation, Physiological↗
PubMedDate not supplied

17-Hydroxyprogesterone level as a marker for corpus luteum function in aborters versus nonaborters.

Weekly serum levels of 17-hydroxyprogesterone (17-OHP) levels and serum progesterone (P) levels were measured in 378 pregnant women. Normal levels of 17-OHP were established in women taking ovulation-inducing drugs (OVID) versus those conceiving on normal cycles. Weekly levels of 17-OHP were measured in women who aborted and were compared with the established norms. The levels of 17-OHP in aborters were lower than in normals for their specific category established in nonaborters. These results suggest that a failing corpus luteum may contribute to some abortions. Careful attention to 17-OHP levels dropping below normal during the first trimester may alert the clinician to the need to increase progesterone exogenously and possibly prevent an abortion.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Confirmation of leucogentian violet in chicken fat by gas chromatography/mass spectrometry.

A gas chromatographic/mass spectrometric (GC/MS) procedure for confirming the identity of leucogentian violet (LGV) in chicken fat was developed for regulatory application. The unused portion of the extract remaining from a determinative procedure was back-extracted into an organic phase, concentrated, and analyzed by GC/MS. Confirmation of the identity of LGV was based on matching the retention times and relative abundances of 6 ions in the extract to corresponding values obtained for the LGV standard. The procedure was validated by replicate analyses of negative control, fortified control, and residue-incurred chicken fat. The presence of LGV was confirmed by the GC/MS procedure in all samples found to contain LGV by prior liquid chromatographic analyses. There were no interferences in the control samples.

Adipose Tissue↗