108 research outputs found
Spectrophotometric studies on the pH of frog skeletal muscle. PH change during and after contractile activity.
In Vivo Measurement of Cerebral Mitochondrial Metabolism Using Broadband Near Infrared Spectroscopy Following Neonatal Stroke
Neonatal stroke presents with features of encephalopathy and can result in significant morbidity and mortality. We investigated the cerebral metabolic and haemodynamic changes following neonatal stroke in a term infant at 24 h of life. Changes in oxidation state of cytochrome-c-oxidase (oxCCO) concentration were monitored along with changes in oxy- and deoxy- haemoglobin using a new broadband near-infrared spectroscopy (NIRS) system. Repeated transient changes in cerebral haemodynamics and metabolism were noted over a 3-h study period with decrease in oxyhaemoglobin (HbO2), deoxy haemoglobin (HHb) and oxCCO in both cerebral hemispheres without significant changes in systemic observations. A clear asymmetry was noted in the degree of change between the two cerebral hemispheres. Changes in cerebral oxygenation (measured as HbDiff=HbO2-HHb) and cerebral metabolism (measured as oxCCO) were highly coupled on the injured side of the brain
Differential diagnosis in spinal and bulbar muscular atrophy clinical and molecular aspects
Kennedy disease is caused by an enlarged trinucleotide repeat sequence within the androgen receptor gene. We report here seven male patients with a benign motor neuron syndrome highly analogous to Kennedy disease but with a normal trinucleotide repeat
A Model of Brain Circulation and Metabolism: NIRS Signal Changes during Physiological Challenges
We construct a model of brain circulation and energy metabolism. The model is
designed to explain experimental data and predict the response of the
circulation and metabolism to a variety of stimuli, in particular, changes in
arterial blood pressure, CO2 levels, O2 levels, and
functional activation. Significant model outputs are predictions about blood
flow, metabolic rate, and quantities measurable noninvasively using
near-infrared spectroscopy (NIRS), including cerebral blood volume and
oxygenation and the redox state of the CuA centre in cytochrome
c oxidase. These quantities are now frequently measured in
clinical settings; however the relationship between the measurements and the
underlying physiological events is in general complex. We anticipate that the
model will play an important role in helping to understand the NIRS signals, in
particular, the cytochrome signal, which has been hard to interpret. A range of
model simulations are presented, and model outputs are compared to published
data obtained from both in vivo and in vitro
settings. The comparisons are encouraging, showing that the model is able to
reproduce observed behaviour in response to various stimuli
Comparison of oxygenation kinetics measured by different placements of the NIRS probe during sustained isometric gripping
Quality control and assurance in functional near infrared spectroscopy (fNIRS) experimentation
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