Duration and Placement of Sleep in a "Disentrained" Environment

Sleep/wake cycles of 9 young adults were electrographically recorded during 60 hrs of enforced bedrest. During this period subjects were required to lie quietly, with no time cues and minimal exogenous stimulation. Sleep and wakefulness patterns were clearly modified under these conditions. There was an alternation of waking periods with an average length of 2.7 hrs and sleep episodes with a mean duration of 2.99 hrs. Eighty percent of both sleep and waking periods were less than 4 hrs duration. The circadian pattern of sleep period duration persisted in disentrainment, but temporal organization of sleep episodes was substantially disrupted; sleep episodes occurred throughout the 24-hr day. The results suggest the presence of two distinct components of the human sleep system–one, sleep duration, is controlled by an endogenous circadian oscillatory system; another, sleep placement, is controlled primarily by behavioral controls, in the form of social and occupational pressures, and self-imposed behavioral alternatives to sleep.     

Skin Conductance Response Conditioning with High CS Intensities: Additional Evidence with New Controls

In an effort to determine whether or not conditioning is possible when CS intensity is at least as high as US intensity, nine groups of human subjects were employed in a skin conductance conditioning study. White noise CS and US intensities of 95- and 115-dB were varied orthogonally in the experimental groups, while control groups were incorporated to control for overall signal frequency and differences in habituation rates attributable to differences in intertrial interval. By conventional contrasts first interval response (FIR) conditioning was observed, but when controls for differential habituation rates were incorporated in the contrasts there was no evidence of FIR conditioning. Second interval response (SIR) conditioning was obtained, but it was manifest as an anticipatory response to the higher of two US intensities rather than in conventional conditioning vs control group comparisons. It was also shown that high CS intensities induce suppression of SIR levels, with greater suppression associated with the higher intensity. Several conclusions were made: 1) in a simple trace conditioning paradigm with skin conductance responding as the measure, it is not clear that what we have typically called a conditioning effect is separable from an habituation effect; 2) conditioning is possible even when CS intensity is as high as or higher than US intensity; and 3) the use of time sample measurement in the absence of signals provides a useful baseline for determining overall increases and decreases in SIR level.     

Spatial Modeling and Analysis of Heat-Related Morbidity in Maricopa County,Arizona

The objective of the present study was to examine the effects of a confluence of demographic, socioeconomic, housing, and environmental factors that systematically contribute to heat-related morbidity in Maricopa County, Arizona, from theoretical, empirical, and spatial perspectives. The present study utilized ordinary least squares (OLS) regression and multiscale geographically weighted regression (MGWR) to analyze health data, U.S. census data, and remotely sensed data. The results suggested that the MGWR model showed a significant improvement in goodness of fit over the OLS regression model, which implies that spatial heterogeneity is an essential factor that influences the relationship between these factors. Populations of people aged 65+, Hispanic people, disabled people, people who do not own vehicles, and housing occupancy rate have much stronger local effects than other variables. These findings can be used to inform and educate local residents, communities, stakeholders, city managers, and urban planners in their ongoing and extensive efforts to mitigate the negative impacts of extreme heat on human health in Maricopa County.     

Abordajes en cirugía tiroidea

Thyroidectomy is the most frequent procedure in endocrine surgery. The conventional approach through a collar incision, as described by Kocher in XIX^th century, has become the “gold standard”. It is continuously evolving in spite of, many years ago, it showed to be safe and efficient with quality standards difficult to beat.Endoscopic and robotic surgery have developed “new approaches” to thyroid in order to improve the cosmetic results, looking even for invisible scars.We have done a thoughtful review of most of them trying to understand their benefits and drawbacks.Currently none of these “new approaches” have been shown to be better than conventional open thyroidectomy beyond offering a better cosmetic result. Besides, only a small percentage of patients can benefit of them. However, most of these approaches will remain if they treat the diseased thyroid and also improve the quality of life of our patients.     

Remote medulla ablongata ventral acute subarachnoid hemorrhage following cervical spinal surgery: A case report

IntroductionThe incidence of remote intracranial hemorrhage (RICH) in patients during spinal surgery is rare and the detailed mechanism remains unclear.Presentation of caseA 55-year-old man had undergone cervical discectomy and fusion at C5–6 and C6–7 due to herniated disc and secondary spinal canal stenosis. He had severe headache 20 h postoperatively and his drain output increased from 100 to 350 mL in the second 10 h after surgery. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed and he was diagnosed with acute subarachnoid hemorrhage in the ventral medulla oblongata. The drainage tube was quickly removed. Infusion of hypertonic saline was used to reduce intracranial pressure and nimodipine prevented vasospasm around the brainstem. The patient made a gradual, satisfactory recovery with conservative treatment.DiscussionThe most likely pathomechanism leading to RICH is venous bleeding due to rapid leak of a large amount of cerebral spinal fluid (CSF) after spinal surgery. If the patient has a headache or neurological complaints after spinal surgery, immediate imaging is recommended to confirm the diagnosis. Treatment depends on the amount and location of intracranial hemorrhage.ConclusionRICH is a serious but rare complication of spinal surgery and cerebellar hemorrhage is the most common. The most important pathomechanism leading to RICH after spinal surgery is venous bleeding due to rapid leak of a large amount of CSF. Timely CT is necessary to exclude RICH. Treatment of RICH depends on the size of the intracranial hematoma and the patient’s symptoms.     

The relative ethylumbelliferone dealkylase activity characterizing the effect of different inducers on the hydroxylase system in the liver musomes of female mice

d,l-Camphor was detected as a new inducer of hydroxylase in the liver musomes of female mice. After a 2-day inhalation of d,l-camphor, cyt. P-450 and the ethylumbelliferone dealkylase were increased by 250 per cent and the NADPH-cyt. P-450 reductase by 350 per cent. The product [NADPH-cyt. P-450 reductase activity × cyt. P450 concentration] was shown to be a suitable reference parameter for the ethylumbelliferone dealkylase activity in the liver musomes during the treatment with four different inducers. The relative dealkylase activity Q was much decreased during inhalation of cyclohexane or d,l-camphor.

$\text{Q =}\text{mU ethylumbelliferone dealkylase}\text{mU NADPH-cty. P-450 reductase × nmoles cty. P-450/mg protein}$

Obviously these two inducers preferably enhanced cyt. P-450 species with a low dealkylase activity. The Q-values were reproducible. Q was increased by 100 per cent during induction of a MC-sensitive mouse strain with 3-methylcholanthrene, but it was only moderately decreased by induction with phenobarbital. Corresponding to this, methylcholanthrene is known to selectively induce a cyt. P-448 with high dealkylase activity whereas phenobarbital is known to change the hydroxylase specificity in the liver musomes not very much.     

Remote memory in epilepsy

PURPOSE: There is now a considerable amount of research relating to memory functioning in epilepsy. The majority of studies have focused on the retention of new information, and few reports have measured memory for past events. This study aims to redress this and measure the efficiency of remote memory in epilepsy. METHODS: A remote memory questionnaire was prepared and administered to three groups of patients with epilepsy and a control group without epilepsy. The questionnaire assessed knowledge of public events that occurred between 1980 and 1991, inclusive. The epilepsy groups comprised 33 patients with temporal lobe epilepsy (TLE), 33 with extratemporal epilepsy (ExTE), and 10 with primary generalized epilepsy (PGE). Thirty control subjects were tested. RESULTS: Patients with TLE performed significantly less well on the questionnaire than all other groups (p = 0.001), but no effect of laterality was recorded; patients with extratemporal or primary generalised epilepsy did not differ from controls. Performance on the questionnaire was not determined by verbal IQ, educational achievement, social class, or drug treatment, but was related to the number of generalised convulsions that had occurred since 1980. The strongest neuropsychological predictors of performance on this questionnaire were measures of verbal memory. CONCLUSIONS: The study demonstrated weak memory for past events in patients with TLE, thereby providing evidence of a broader memory disturbance in this group than has been previously highlighted. A test of remote memory, such as the one designed for this study, is easy to administer and provides clinically important information not available from conventional neuropsychological tests.     

遥控推注机器臂辅助下椎体成形术对避免术者放射线暴露的临床评价

目的：引入一种新型的可远程操作的骨水泥推注机器臂,初步评价在其辅助下的椎体成形术治疗脊柱转移瘤的临床应用价值。方法对2012年7至2013年6月,我科收治的20例脊柱转移瘤患者的30个病变椎体行椎体成形术,其中手动组10例（16个椎体）,行传统椎体成形术;机器臂推注（RCIM）组10例（14个椎体）,在可遥控操作的骨水泥推注机器臂辅助下完成。RCIM组整个骨水泥推注过程中,通过术中X线透视全程监控,术者远离手术野,在屏蔽保护下完成遥控操作,从而免受放射线照射。手术前后采用视觉模拟评分（visualanaloguescale,VAS）评价所有患者疼痛程度,同时利用放射线测量仪测量患者和术者放射线暴露剂量。结果手动组术前、术后VAS评分分别为8.3±1.0和4.6±0.9,改善明显,差异有统计学意义（P＝0.000）;RCIM组术前、术后VAS评分分别为7.6±1.1和4.1±0.8,改善明显,差异有统计学意义（P＝0.000）。术前、术后VAS评分,组间差异无统计学意义（P＞0.05）。手动组和RCIM组患者放射线暴露剂量分别为（32.4±12.1）uSv和（35.1±11.7）uSv,差异无统计学意义（P＞0.05）;而两组术者在术中的放射线暴露剂量分别为（28.9±15.2）uSv和（0.29±0.014）uSv,手动组放射线暴露量显著高于RCIM组,差异有统计学意义（P＜0.05）。结论与传统椎体成形术的操作不同,机器臂辅助下的椎体成形术使术者在进行骨水泥推注时,完全免受放射线的伤害;与此同时,通过术中X线透视全程监控,理论上亦相对增加了骨水泥推注过程的安全性。