Anatomical Substrates of Rapid Eye Movement Sleep Rebound in a Rodent Model of Post-sevoflurane Sleep Disruption

BACKGROUND

Previous research suggests that sevoflurane anesthesia may prevent the brain from accessing rapid eye movement (REM) sleep. If true, then patterns of neural activity observed in REM-on and REM-off neuronal populations during recovery from sevoflurane should resemble those seen after REM sleep deprivation. In this study, the authors hypothesized that, relative to controls, animals exposed to sevoflurane present with a distinct expression pattern of c-Fos, a marker of neuronal activation, in a cluster of nuclei classically associated with REM sleep, and that such expression in sevoflurane-exposed and REM sleep-deprived animals is largely similar.

METHODS

Adult rats and Targeted Recombination in Active Populations mice were implanted with electroencephalographic electrodes for sleep-wake recording and randomized to sevoflurane, REM deprivation, or control conditions. Conventional c-Fos immunohistochemistry and genetically tagged c-Fos labeling were used to quantify activated neurons in a group of REM-associated nuclei in the midbrain and basal forebrain.

RESULTS

REM sleep duration increased during recovery from sevoflurane anesthesia relative to controls (157.0 ± 24.8 min vs. 124.2 ± 27.8 min; P = 0.003) and temporally correlated with increased c-Fos expression in the sublaterodorsal nucleus, a region active during REM sleep (176.0 ± 36.6 cells vs. 58.8 ± 8.7; P = 0.014), and decreased c-Fos expression in the ventrolateral periaqueductal gray, a region that is inactive during REM sleep (34.8 ± 5.3 cells vs. 136.2 ± 19.6; P = 0.001). Fos changes similar to those seen in sevoflurane-exposed mice were observed in REM-deprived animals relative to controls (sublaterodorsal nucleus: 85.0 ± 15.5 cells vs. 23.0 ± 1.2, P = 0.004; ventrolateral periaqueductal gray: 652.8 ± 71.7 cells vs. 889.3 ± 66.8, P = 0.042).

CONCLUSIONS

In rodents recovering from sevoflurane, REM-on and REM-off neuronal activity maps closely resemble those of REM sleep-deprived animals. These findings provide new evidence in support of the idea that sevoflurane does not substitute for endogenous REM sleep.

EDITOR’S PERSPECTIVE

Diverse processing of pharmacological and natural rewards by the central amygdala

The central amygdala (CeA) with its medial (CeM) and lateral (CeL) nuclei is the brain hub for processing stimuli with emotional context. CeL nucleus gives a strong inhibitory input to the CeM, and this local circuitry assigns values (positive or negative) to incoming stimuli, guiding appropriate behavior (approach or avoid). However, the particular involvement of CeA in processing such emotionally relevant information and adaptations of the CeA circuitry are not yet well understood. In this study, we examined synaptic plasticity in the CeA after exposure to two types of rewards, pharmacological (cocaine) and natural (sugar). We found that both rewards engage CeM, where they generate silent synapses resulting in the strengthening of the network. However, only cocaine triggers plasticity in the CeL, which leads to the weakening of its excitatory inputs. Finally, chemogenetic inhibition of CeM attenuates animal preference for sugar, while activation delays cocaine-induced increase in locomotor activity.

Whole-brain tracking of cocaine and sugar rewards processing

Natural rewards, such as food, and sex are appetitive stimuli available for animals in their natural environment. Similarly, addictive rewards such as drugs of abuse possess strong, positive valence, but their action relies on their pharmacological properties. Nevertheless, it is believed that both of these kinds of rewards activate similar brain circuitry. The present study aimed to discover which parts of the brain process the experience of natural and addictive rewards. To holistically address this question, we used a single-cell whole-brain imaging approach to find patterns of activation for acute and prolonged sucrose and cocaine exposure. We analyzed almost 400 brain structures and created a brain-wide map of specific, c-Fos-positive neurons engaged by these rewards. Acute but not prolonged sucrose exposure triggered a massive c-Fos expression throughout the brain. Cocaine exposure on the other hand potentiated c-Fos expression with prolonged use, engaging more structures than sucrose treatment. The functional connectivity analysis unraveled an increase in brain modularity after the initial exposure to both types of rewards. This modularity was increased after repeated cocaine, but not sucrose, intake. To check whether discrepancies between the processing of both types of rewards can be found on a cellular level, we further studied the nucleus accumbens, one of the most strongly activated brain structures by both sucrose and cocaine experience. We found a high overlap between natural and addictive rewards on the level of c-Fos expression. Electrophysiological measurements of cellular correlates of synaptic plasticity revealed that natural and addictive rewards alike induce the accumulation of silent synapses. These results strengthen the hypothesis that in the nucleus accumbens drugs of abuse cause maladaptive neuronal plasticity in the circuitry that typically processes natural rewards.

Effects of chair vibration on indoor annoyance ratings of sonic booms

The effects of perceptible whole-body vibrations on annoyance ratings of sonic booms and other impulsive environmental sounds experienced indoors were studied. Fifteen pairs of test subjects made annoyance ratings while seated in a living room environment. There were two chairs, one isolated from floor vibrations and the other not isolated, and every test subject rated all signals in both chairs. Halfway through each test session, subjects changed seats. Subjects who sat in the isolated chair first gave lower mean annoyance ratings in both halves of the test than subjects who sat in the non-isolated chair first. Annoyance predictions from models using both sound and vibration measures were closer to average annoyance ratings than predictions from a model using sound measures alone. Reformulation of the annoyance model revealed that the presence of perceptible vibration is equivalent to increasing acoustic metric Perceived Level by 4.8 dB when calculated on exterior signals and by 5.6 dB when calculated on interior signals.

Aberrant effects of altrenogest and exposure to exogenous gonadotropins on follicular cysts appearance in gilts

Research was conducted to determine the effect of altrenogest and exposure to exogenous gonadotropins on ovarian function in prepubertal and mature gilts. Crossbred, presumably sexually mature gilts (n = 51), were fed with altrenogest for 18 consecutive days and the day after the last feeding with altrenogest, gilts were treated with eCG and 72 hours later challenged with hCG. Animals were slaughtered on Days 10 to 13 of their gonadotropins synchronized estrous cycle. Ovaries were examined for the number of CL, number of follicular cysts, and presence of corpora albicantia. Gilts were divided into two groups: those possessing corpora albicantia (group A-mature; n = 36) and those without corpora albicantia (Group W-prepubertal; n = 15) on their ovaries. In addition, each group was divided into two subgroups depending on the presence of follicular cysts (AC and WC) or their absence (AO and WO). There was no difference between the number of CL in group A and group W. Presence of corpora albicantia determined percentage of gilts possessing follicular cysts (13.9% group A vs. 66.7% group W). Gilts without follicular cysts (AO plus WO; n = 36) had higher number of CL (P < 0.01) than gilts bearing cysts (AC plus WC; n = 15). Comparison AO-AC did not show significant difference (P = 0.075) between CL number in mature cyst-free and cysts bearing gilts. A prepubertal gilts not bearing follicular cysts (WO) had higher (P < 0.02) number of CL than gilts bearing cysts. A significant negative correlation between the number of CL and number of follicular cysts was found (r = -0.664; P = 0.007). There were no differences in blood plasma progesterone and estradiol concentration between cyst-free and cyst-bearing gilts. These results indicate: (1) a higher follicular cysts appearance in prepubertal than mature gilts challenged with altrenogest and exposed to exogenous gonadotropins and (2) a negative effect of follicular cysts on the number of CL (ovulations) in prepubertal gilts.

A microfluidic opto-caloric switch for sorting of particles by using 3D-hydrodynamic focusing based on SLE fabrication capabilities

In a miniaturised flow switch fluid flows are controlled by reducing the local viscosity via absorption of laser radiation. Through this, the local flow rates are increased to switch the outlet port of a fluid flow carrying the analyte. The microfluidic chip is fabricated using Selective Laser-Induced Etching (SLE). SLE allows novel 3D-hydrodynamic focusing, realising circular shaped channel cross-sections and adapting interaction volume geometries to the profile of the laser radiation for optimised absorption. The performance of the switch is validated experimentally with a dyed analyte and video image processing. The ability to sort particles like cells is demonstrated at 8 Hz using polystyrene beads having a diameter of 8 μm.

Karyotype and nuclear DNA content of hexa-, octo-, and duodecaploid lines of Bromus subgen. Ceratochloa

The subgenus Ceratochloa of the genus Bromus includes a number of closely related allopolyploid forms or species that present a difficult taxonomic problem. The present work combines data concerning chromosome length, heterochromatin distribution and nuclear genome size of different 6x, 8x and 12x accessions in this subgenus. Special attention is paid to the karyotype structure and genomic constitution of duodecaploid plants recently found in South America. Hexaploid lineages possess six almost indistinguishable genomes and a nuclear DNA content between 12.72 pg and 15.10 pg (mean 1Cx value = 2.32 pg), whereas octoploid lineages contain the same six genomes (AABBCC) plus two that are characterized by longer chromosomes and a greater DNA content (1Cx = 4.47 pg). Two duodecaploid accessions found in South America resemble each other and apparently differ from the North American duodecaploid B. arizonicus as regards chromosome size and nuclear DNA content (40.00 and 40.50 pg vs. 27.59 pg). These observations suggest that the South American duodecaploids represent a separate evolutionary lineage of the B. subgenus Ceratochloa, unrecognized heretofore.

Comparing subjective and digital image analysis HER2/neu expression scores with conventional and modified FISH scores in breast cancer

BACKGROUND

HER2/neu expression and fluorescence in situ hybridisation (FISH) amplification have therapeutic significance.

AIMS

To compare subjective HER2/neu expression scores with digital image analysis (DIA) and conventional and modified FISH scores in breast cancer.

METHODS

Sixty HercepTest-immunostained breast carcinomas, prospectively scored as consensus 2+ and 3+ (DAKO protocol) by two observers, were analysed with DIA, and conventional (Vysis) and modified FISH scoring protocols.

RESULTS

With consensus scoring, 23 (38%) of the 60 cases were 2+ and 37 (62%) were 3+. Agreement with DIA scores was 100%. With conventional FISH scoring, 4 of the 3+ cases did not show amplification, but all of those negative cases had high HER2/neu copy numbers. With the modified FISH scoring protocol, all HercepTest immunohistochemical 3+ cases were amplified. Of the 2+ cases, 3 were amplified with the modified FISH protocol and 4 with the conventional FISH protocol.

CONCLUSIONS

Modified FISH scores were better correlated with HercepTest 3+ consensus and DIA scores than were conventional FISH scores. HER2/neu DIA scoring is a cost-effective supplementary tool in surgical pathology.

Lattice Monte Carlo simulations of three-dimensional charged polymer chains

The configurational properties of strongly charged polyelectrolytes accompanied by neutralizing counterions in dilute solutions are simulated using the cooperative motion algorithm on the face-centered-cubic lattice. The full Coulomb potential and the excluded volume condition between different ions/beads are taken into account and the reduced temperature T* is considered the main, variable parameter. The calculations that have been carried out for solutions of both single and several chains indicate a few regions of their behavior: (1) for T*--> infinity, it corresponds to that of neutral, self-avoiding polymers under good solvent conditions; (2) for T* approximately 1, due to the electrostatic interactions being effectively stronger, the chains are more outstretched compared to their size at other temperatures; (3) for T* well below one, the counterion condensation becomes more and more dominant, which gradually leads to strongly collapsed chains; and (4) at the lowest temperatures the chains and counterions assume low-energy configurations in the form of neutral, compact aggregates.

Lattice Monte Carlo simulations of three-dimensional charged polymer chains. II. Added salt

The configurational properties of strongly charged polyelectrolytes accompanied by counterions and salt ions in dilute solutions are simulated using the cooperative motion algorithm on the face-centered-cubic lattice. The calculations indicate that both positive and negative ions condense on the chains at sufficiently low temperatures and their amount depends on the concentration of added salt. As the temperature decreases from high to low, the chains undergo conformational changes from neutral-like, self-avoiding polymers by more outstretched forms to compact globules. The observed extension of the chains at intermediate temperatures is also affected by the amount of salt. Furthermore, configurations with the lowest energies recorded at the lowest temperatures are aggregates of single or more entangled chains and ions of both types.

Effect of a standard exercise protocol on shoulder pain in long-term wheelchair users

PURPOSE

To analyze the effectiveness of a 6-month exercise protocol on shoulder pain experienced by wheelchair users during functional activities.

SUBJECTS

Forty-two wheelchair users, 35 males and seven females: average age of 35 years and an average duration of wheelchair use of 14 years.

METHODS

Subjects were randomly assigned to treatment (n=21) and control (n=21) groups. The treatment group received instruction in five shoulder exercises which they performed daily for 6 months. The exercise protocol included two exercises for stretching anterior shoulder musculature and three exercises for strengthening posterior shoulder musculature.

OUTCOME MEASURES

All subjects completed a self-report questionnaire and the Wheelchair Users Shoulder Pain Index (WUSPI) initially and at bimonthly intervals during the 6-month intervention.

RESULTS

Seventy-five per cent of the subjects reported a history of shoulder pain since beginning wheelchair use. The average initial performance-corrected (PC-WUSPI) score of the 42 subjects was 17.7 (+/-21.3) with a range of 0-103.2 points. Over 83% of the subjects (35 of 42) completed the 6-month study. Subjects in the treatment group decreased their PC-WUSPI score by an average of 39.9%, compared to decreases of only 2.5% in the control group.

CONCLUSIONS

These findings supported the effectiveness of this exercise protocol in decreasing the intensity of shoulder pain which interferes with functional activity in wheelchair users.

Primary small cell (oat cell) carcinoma of the larynx associated with an IgD multiple myeloma

Primary small cell (oat cell) carcinoma of the larynx is a rare condition. We report a case of primary oat cell carcinoma of the subglottic larynx associated with a synchronous IgD multiple myeloma (an unreported association). An increased incidence of carcinoma associated with plasma cell disorders has been reported, and the theories of this association are discussed. In a review of the reported cases, the most successful management of oat cell carcinoma of the larynx appears to incorporate a combination of radiotherapy and chemotherapy. Our case was treated with a combination of protocols used for oat cell carcinoma of the larynx and multiple myeloma. At 24 months after diagnosis, the patient is free of oat cell carcinoma, and the multiple myeloma is under control.