We measured quantitative cortical mantle cerebral blood flow (CBF) by stable xenon computed tomography (CT) within the first 12 h after severe traumatic brain injury (TBI) to determine whether ...neurologic outcome can be predicted by CBF stratification early after injury. Stable xenon CT was used for quantitative measurement of CBF (mL/100 g/min) in 22 cortical mantle regions stratified as follows: low (0-8), intermediate (9-30), normal (31-70), and hyperemic (>70) in 120 patients suffering severe (Glasgow Coma Scale GCS score ≤8) TBI. For each of these CBF strata, percentages of total cortical mantle volume were calculated. Outcomes were assessed by Glasgow Outcome Scale (GOS) score at discharge (DC), and 1, 3, and 6 months after discharge. Quantitative cortical mantle CBF differentiated GOS 1 and GOS 2 (dead or vegetative state) from GOS 3-5 (severely disabled to good recovery; p<0.001). Receiver operating characteristic (ROC) curve analysis for percent total normal plus hyperemic flow volume (TNHV) predicting GOS 3-5 outcome at 6 months for CBF measured <6 and <12 h after injury showed ROC area under the curve (AUC) cut-scores of 0.92 and 0.77, respectively. In multivariate analysis, percent TNHV is an independent predictor of GOS 3-5, with an odds ratio of 1.460 per 10 percentage point increase, as is initial GCS score (OR=1.090). The binary version of the Marshall CT score was an independent predictor of 6-month outcome, whereas age was not. These results suggest that quantitative cerebral cortical CBF measured within the first 6 and 12 h after TBI predicts 6-month outcome, which may be useful in guiding patient care and identifying patients for randomized clinical trials. A larger multicenter randomized clinical trial is indicated.
The relationship between arterial and venous blood flow in moderate-to-severe traumatic brain injury (TBI) is poorly understood.
was to compare differences in perfusion computed tomography ...(PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe TBI as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow.
Moderate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (severe TBI after the surgery). Arterial and venous CBF were measured by PCT in both the internal carotid arteries (CBFica) and the confluence of upper sagittal, transverse, and straight sinuses (CBFcs).
In group I, CBFica on the left and right sides were significantly correlated with each other (p < 0.0001) and with CBFcs (p = 0.048). In group II, CBFica on the left and right sides were also correlated (P < 0.0000001) but not with CBFcs. Intracranial pressure reactivity (PRx) and CBFcs were correlated (p = 0.00014). In group III, CBFica on the side of the removed hematoma was not significantly different from the opposite CBFica (P = 0.680) and was not correlated with CBFcs.
The increasing severity of TBI is accompanied by a rising uncoupling between the arterial and venous CBF in the supratentorial vessels suggesting a shifting of cerebral venous outflow.
•The increasing traumatic brain injury severity is accompanied by a rising uncoupling between the arterial and venous cerebral blood flow.
Clear micelle gel dosimeter with nanoclay Hayashi, K; Nemoto, M; Takanashi, T ...
Journal of physics. Conference series,
08/2019, Letnik:
1305, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We built a clear micelle gel dosimeter with nanoclay. Jordan et al. reported that Laponite RD clay nanoparticles when added to radiochromic leucomalachite green micelle gels eliminate diffusion and ...increase the dose sensitivity by roughly ten folds. However, owing to the cloudiness of the sample, there was a problem in reading the optical computed tomography (CT). In this study, we constructed a nanoclay-added micelle gel dosimeter by changing the type of gelatin. As a result, in addition to yielding a clear gel and making the optical CT readable, diffusion and temporal stability were improved more than the gel without using nanoclay, and the dosimeter showed the same level of sensitivity and diffusion as the one based on Laponite-added micelle gel reported by Jordan et al.
Equal-channel angular pressing (ECAP) was attempted at room temperature to refine grain sizes of six different commercial Al alloys, 1100, 2024, 3004, 5083, 6061 and 7075. Transmission electron ...microscopy revealed that submicrometer grain sizes are attained in these alloys. Tensile tests at room temperature showed that the strength increases with an increase in the number of pressings but the elongation to failure remains little changed following a large decrease after the first pressing. Static annealing experiments demonstrated that the extensive grain growth occurs above ∼200°C in 1100, 3004, 5083 and 6061 but the submicrometer-grained structures are stable in 2024 and 7075 even at 300°C. It was confirmed that the Hall–Petch relationship holds for the ECA-pressed alloys. The effect of sample size was further examined and the applied load was measured during ECAP for the possibility of scaling-up the process.
To manage patients with high intracranial pressure (ICP), clinicians need to know the critical cerebral perfusion pressure (CPP) required to maintain cerebral blood flow (CBF). Historically, the ...critical CPP obtained by decreasing mean arterial pressure (MAP) to lower CPP was 60 mm Hg, which fell to 30 mm Hg when CPP was reduced by increasing ICP. We examined whether this decrease in critical CPP was due to a pathological shift from capillary (CAP) to high-velocity microvessel flow or thoroughfare channel (TFC) shunt flow. Cortical microvessel red blood cell velocity and NADH fluorescence were measured by in vivo two-photon laser scanning microscopy in rats at CPP of 70, 50, and 30 mm Hg by increasing ICP or decreasing MAP. Water content was measured by wet/dry weight, and cortical perfusion by laser Doppler flux. Reduction of CPP by raising ICP increased TFC shunt flow from 30.4±2.3% to 51.2±5.2% (mean±SEM, p<0.001), NADH increased by 20.3±6.8% and 58.1±8.2% (p<0.01), and brain water content from 72.9±0.47% to 77.8±2.42% (p<0.01). Decreasing CPP by MAP decreased TFC shunt flow with a smaller rise in NADH and no edema. Doppler flux decreased less with increasing ICP than decreasing MAP. The decrease seen in the critical CPP with increased ICP is likely due to a redistribution of microvascular flow from capillary to microvascular shunt flow or TFC shunt flow, resulting in a pathologically elevated CBF associated with tissue hypoxia and brain edema, characteristic of non-nutritive shunt flow.
Mild hypothermia renders potent neuroprotection against acute brain injury. Recent reports show that adenosine 5'-monophosphate (AMP) plays a role in thermoregulation and induces hypothermia in mice. ...Therefore, this study sought to determine whether AMP induces hypothermia in rats and to study its collective effects on cerebral ischemia induced by 2-h middle cerebral artery occlusion. An intraperitoneal injection of AMP induced hypothermia dose-dependently. At the dose of 4 mmol/kg, AMP induced promising mild hypothermia for 2.5 h. Unexpectedly, the AMP-induced hypothermia failed to reduce infarct volume after brain ischemia; instead, it exaggerated the ischemic damage, indicated by an increased infarct volume, as well as increased incidences of hemorrhagic transformation, seizure, and animal death. Physiologic parameter monitoring revealed that AMP causes profound hypotension, leading to cerebral hypoperfusion. Furthermore, AMP administration resulted in severe hyperglycemia, metabolic acidosis, and hypocalcemia. In addition, western blots showed early dephosphorylation and degradation of AMP-activated kinase in the ischemic cortex in AMP-treated rats. Taken together, our findings suggest that AMP induces hypothermia in rats, probably by limiting cellular access to glucose. However, the potential neuroprotection of AMP-mediated hypothermia against ischemia was overwhelmed by the detrimental effects of hypotension and hyperglycemia, thus making AMP an unlikely agent for inducing hypothermia to protect the brain against ischemic injury.
OBJECTIVES: To examine the combined association of obesity and low muscle strength with mobility limitation in older adults. DESIGN, SETTING AND PARTICIPANTS: This two-year follow-up longitudinal ...study included pooled data from 283 older community-dwelling Japanese women without mobility limitations who were 65 to 87 years of age (mean age 72.2 ± 5.0 years). MEASUREMENTS: Muscle strength was measured by hand-grip strength (HGS). The participants were categorized by HGS (high muscle strength: HGS ≥19.6 kg, low muscle strength: HGS <9.6 kg) and body mass index (BMI) (obese: BMI ≥25 kg/m², normal weight: BMI <25 kg/m²). The main outcome was mobility limitation, assessed by a self-reported questionnaire (difficulty walking one-half mile or climbing 10 steps without resting). Multivariate logistic regression analysis was performed to determine the combined effect of HGS and BMI on mobility limitation, adjusting for age, exercise habits, medications, and knee pain. RESULTS: During the follow-up period, 82 of 283 participants (29.0%) developed mobility limitation. The adjusted odds ratios (95% confidence interval) for the incidence of mobility limitation were 1.53 (0.86- 2.73) and 2.05 (1.08-3.91) in the obese and low muscle strength groups, respectively. Obesity combined with low muscle strength exhibited a significant and strong association with mobility limitation (odds ratio: 3.88, 1.08-13.91) compared with participants with normal weight and high muscle strength. CONCLUSION: Among community-dwelling older Japanese women, obesity alone was not associated with the incidence of mobility limitation, but when combined with low muscle weakness, the risk of developing mobility limitation was 3.9-fold greater than for the reference group.
N-acetyl proline-glycine-proline（ac-PGP）is a matrix-derived chemoattractant,or matrikine,produced by the degradation of collagen.Ac-PGP was first identified in studies of alkali eye injury in ...rabbits（Pfister et al.,1995）.
Objectives: To determine whether oral capsaicin troche supplementation with every meal upregulates the impairment of upper respiratory protective reflexes such as the swallowing reflex and the cough ...reflex.
Design: Randomized, controlled study with recruitment through nursing homes.
Setting: Sendai, Japan, from September 2002 through December 2003.
Participants: Sixty‐four participants in nursing homes with a mean age±standard deviation of 81.9±1.0 with stable physical status.
Intervention: Participants were randomly assigned to the program for the supplementation of capsaicin trochisci or placebo trochisci before every meal for 4 weeks.
Measurements: Assessment of individual latency time of the swallowing reflex (LTSR) and cough reflex sensitivity.
Results: Before the commencement of this study, there were no significant baseline differences in multiple parameters between the intervention group and control group. LTSR in participants in the intervention group was significantly shorter than in the control group (P<.05). The odds ratio (OR) of the shortening of the LTSR of more than 1 minute in the intervention group was 3.4 (95% confidence interval (CI)=1.1−10.4), compared with the control group (P=.03). In particular, daily capsaicin supplementation significantly increased the ratio of LTSR reduction at 4 weeks after the study to baseline LTSR in the high‐risk group (baseline LTSR >6.0 seconds) compared with the low‐risk group (baseline LTSR <3.0 seconds) and the intermediate group (3.0 seconds <baseline LTSR <6.0 seconds) (P<.005). Seventeen (52.1%) participants in the intervention group and seven (21.9%) in the control group showed improvement in cough reflex sensitivity (OR=4.1, 95% CI=1.4−12.2; P<.01).
Conclusion: Daily capsaicin supplementation resulted in a significant improvement in upper protective respiratory reflexes, particularly in older people with a high risk for aspiration.
PDF
