Highlights • Ischaemic brain injury drives profound changes in the gut microbiota. • The effects of brain injury on the gut microbiota include changes in goblet cells and noradrenaline. • Traumatic ...brain injury (TBI) also changes the gut microbiota.
Abstract
The discovery in recent years by gravity wave detectors of dozens of merging binary black holes with masses much greater than one solar mass, when taken with the known population of black ...holes raises the possibility that it may not be possible to explain their all their origins and growth by credible accretion mechanisms. This paper offers an alternative perspective; that black holes can increase their mass by a quantum process linked to the acceleration of distant matter. Also, the idea that dark matter is predominantly composed of black holes in strongly supported. A testable equation
M
/
M
= 2
H
for the fractional rate of production of dark matter inside a large region of space with radius
r
and mass
M
(
r
), where
H
is the Hubble Constant, is presented. A mechanism to produce early supermassive black holes is proposed.
The green and golden bell frog (Litoria aurea) was once a common Australian Hylid. Today, many populations are small and fragmented as a result of dramatic declines in distribution and abundance. We ...undertook a large‐scale assessment of genetic structure and diversity in L. aurea using four species‐specific microsatellite markers. Twenty‐one locations were sampled from throughout the species range covering 1000 km of the east coast of Australia. Levels of allelic diversity and heterozygosity were high (uncorrected mean alleles/locus and HE were 4.8–8.8 and 0.43–0.8, respectively) compared to other amphibian species and significant differences among sampled sites were recorded. Despite recent population declines, no sites displayed a genetic signature indicative of a population bottleneck. Significant genetic structuring (overall FST 0.172) was detected throughout the species range, but was relatively low compared to previous amphibian studies employing microsatellites. In addition we found that some areas sampled within continuous habitat showed evidence of weak genetic structuring (data subset FST 0.034). We conclude that maintaining areas of continuous habitat is critical to the conservation of the species and argue that population recovery and/or persistence in all areas sampled is possible if appropriate protection and management are afforded.
Muscle twitch threshold has been used to determine optimal stimulus intensity for somatosensory evoked potentials but neuromuscular blockade precludes the use of muscle twitch during surgery. ...Accordingly, nerve action potential (NAP) amplitude was investigated as a surrogate to muscle twitch.
The ulnar and tibial nerves were stimulated at the wrist and ankle, respectively, in 27 patients undergoing spine and brain surgery. After neuromuscular blockade was gone, the stimulus intensity for just maximal NAP amplitude recorded from Erb's point and the popliteal fossa was compared with the stimulus intensity for hypothenar and plantar foot muscle twitch threshold (times two), respectively (Wilcoxon matched pairs test).
There was no significant difference between stimulus intensity for just maximal Erb's point and popliteal fossa NAP amplitude when compared with stimulus intensity for hypothenar and plantar foot twitch threshold (times two), respectively. Eight patients required more than twitch intensity (times two) to obtain maximum NAP.
The NAP amplitude may be used to determine optimal somatosensory evoked potential stimulus intensity when muscle twitch is not visible. This method should improve the success of intraoperative somatosensory evoked potential monitoring and decrease erroneous interpretation.
To determine the relationship between intraoperative flash visual evoked potential (FVEP) monitoring and visual function.
Intraoperative FVEPs were recorded from electrodes placed in the scalp ...overlying the visual cortex (Oz) after flashing red light stimulation delivered by Cadwell LED stimulating goggles in 89 patients. Restrictive filtering (typically 10-100 Hz), optimal reject window settings, mastoid reference site, total intravenous anesthetic (TIVA), and stable retinal stimulation (ensured by concomitant electroretinogram ERG recording) were used to enhance FVEP reproducibility.
The relationship between FVEP amplitude change and visual outcome was determined from 179 eyes. One eye had a permanent intraoperative FVEP loss despite stable ERG, and this eye had new, severe postoperative visual dysfunction. Seven eyes had transient significant FVEP change (>50% amplitude decrease that recovered by the end of surgery), but only one of those had a decrease in postoperative visual acuity. FVEP changes in all eight eyes (one permanent FVEP loss plus seven transient FVEP changes) were related to surgical manipulation. In each case the surgeon was promptly informed of the FVEP deterioration and took remedial action. The other eyes did not have FVEP changes, and none of those eyes had new postoperative visual deficits.
Our FVEP findings relate to visual outcome with a sensitivity and specificity of 1.0. New methods for rapidly acquiring reproducible FVEP waveforms allowed for timely reporting of significant FVEP change resulting in prompt surgical action. This may have accounted for the low postoperative visual deficit rate (1%) in this series.
To relate early somatosensory evoked potential grades from comatose traumatic brain injury patients to neuropsychological and functional outcome 1 yr later; to determine the day (within the first ...week after traumatic brain injury) that somatosensory evoked potential grade best correlates with outcome; to determine whether somatosensory evoked potential grade improvement in the first week after traumatic brain injury is associated with improved outcome.
Prospective cohort study.
Critical care unit at a university hospital.
Median nerve somatosensory evoked potentials were obtained from 81 comatose patients with traumatic brain injury. Somatosensory evoked potential grades were calculated from results obtained on days 1, 3, and 7 after traumatic brain injury. Glasgow Outcome Scale, Barthel Index, Rivermead Head Injury Follow-up Questionnaire, General Health Questionnaire, Stroop Color-Word Test, Paced Auditory Serial Addition Task, and Symbol-Digit Modalities Test scores were obtained 1 yr after injury.
None.
Somatosensory evoked potential grade on days 1, 3, and 7 related significantly with Glasgow Outcome Scale and Barthel scores (day 3 better than day 1) but did not relate with Rivermead Head Injury Follow-up Questionnaire or General Health Questionnaire scores. Day 3 and day 7 somatosensory evoked potential grades related significantly with Stroop scores. Day 3 somatosensory evoked potential grades related significantly with Symbol-Digit Modalities Test scores. Patients with bilaterally present but abnormal somatosensory evoked potentials, whose somatosensory evoked potential grade improved between days 1 and 3, had marginally better functional outcome than those without somatosensory evoked potential grade improvement.
Day 3 somatosensory evoked potential grade related to information-processing speed, working memory, and the ability to attend to tasks 1 yr after traumatic brain injury. Day 3 somatosensory evoked potential grade had the strongest relationship with functional outcome. Somatosensory evoked potential grades were not related to emotional well-being.
A 3.5-year-old child with hypertrophic obstructive cardiomyopathy and recurrent syncope underwent surgical left-ventricular outflow tract myectomy and implantation of a single-chamber automatic ...cardioverter defibrillator. A single-coil active fixation lead was introduced via a purse-string suture in the right atrial appendage and the lead tip positioned and fixed in the right-ventricular apex under direct visualization via a small right atriotomy incision. Described configuration may be considered in small children undergoing intracardiac surgery at the time of defibrillator implantation.
Transcranial magnetic stimulation (TCMS) causes leg muscle contractions, but the neural structures in the brain that are activated by TCMS and their relationship to these leg muscle responses are not ...clearly understood. To elucidate this, we concomitantly recorded leg muscle responses and thoracic spinal cord-evoked potentials (SCEPs) after TCMS for the first time in 10 awake, neurologically intact human subjects. In this report we provide evidence of direct and indirect activation of corticospinal neurons after TCMS. In three subjects, SCEP threshold (T) stimulus intensities recruited both the D wave (direct activation of corticospinal neurons) and the first I wave (I1, indirect activation of corticospinal neurons). In one subject, the D, I1, and I2 waves were recruited simultaneously, and in another subject, the I1 and I2 waves were recruited simultaneously. In the remaining five subjects, only the I1 wave was recruited first. More waves were recruited as the stimulus intensity increased. The presence of D and I waves in all subjects at low stimulus intensities verified that TCMS directly and indirectly activated corticospinal neurons supplying the lower extremities. Leg muscle responses were usually contingent on the SCEP containing at least four waves (D, I1, I2, and I3).
The koala, Phascolarctos cinereus, is a geographically widespread species endemic to Australia, with three currently recognized subspecies: P.c. adustus, P.c. cinereus, and P.c. victor. Intraspecific ...variation in the mitochondrial DNA (mtDNA) control region was examined in over 200 animals from 16 representative populations throughout the species’ range. Eighteen different haplotypes were defined in the ≈ 860 bp mtDNA control region, as determined by heteroduplex analysis/temperature gradient gel electrophoresis (HDA/TGGE). Any single population typically possessed only one or two haplotypes yielding an average within‐population haplotypic diversity of 0.180 ± 0.003, and nucleotide diversity of 0.16%. Overall, mtDNA control region sequence diversity between populations averaged 0.67%, and ranged from 0% to 1.56%. Nucleotide divergence between populations averaged 0.51%, and ranged from 0% to 1.53%. Neighbour‐joining methods revealed limited phylogenetic distinction between geographically distant populations of koalas, and tentative support for a single evolutionarily significant unit (ESU). This is consistent with previous suggestions that the morphological differences formalized by subspecific taxonomy may be interpreted as clinal variation. Significant differentiation in mtDNA‐haplotype frequencies between localities suggested that little gene flow currently exists among populations. When combined with microsatellite analysis, which has revealed substantial differentiation among koala populations, we conclude that the appropriate short‐term management unit (MU) for koalas is the local population.
The amplitude of the cortically generated somatosensory evoked potential (SSEP) is used to predict outcome in comatose patients. The relationship between epileptiform discharges and SSEP amplitude ...has not been elucidated in those patients.
Bilateral median nerve SSEP and electroencephalograph (EEG) studies were performed in a comatose patient (patient 1) 1 day after cardiac surgery and repeated 4 days later. He had tranexamic acid administered before and during surgery. Another comatose patient (patient 2) had the same studies performed 1 day after sustaining 10 minutes of pulseless electrical cardiac activity.
Both comatose patients had epileptiform discharges (on EEG) that were coincident with giant cortically generated SSEPs. In patient 1, the EEG and SSEP studies repeated 5 days postoperatively showed no epileptiform discharges, and the cortically generated SSEP amplitude was decreased (normalized) compared with that obtained one day postoperatively. He emerged from coma and had a good recovery. Patient 2 died shortly after EEG and SSEP testing.
Epileptiform discharges were associated with giant cortically generated median nerve SSEP amplitude (tranexamic acid was implicated in patient 1 and anoxic brain injury in patient 2). Accordingly, those who use the amplitude of cortically generated SSEPs for predicting outcome in comatose patients should consider the presence of epileptiform discharges (detected by EEG) as a potential confounding factor.
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