Isolated rat hepatocytes were pulse-labelled with [35S]methionine at 37 degrees C and subsequently incubated (chased) for different periods of time at different temperatures (37-16 degrees C). The time courses for the secretion of [35S]methionine-labelled albumin and haptoglobin were determined by quantitative immunoprecipitation of the detergent-solubilized cells and of the chase media. Both proteins appeared in the chase medium only after a lag period, the length of which increased markedly with decreasing chase temperature: from about 10 and 20 min at 37 degrees C to about 60 and 120 min at 20 degrees C for albumin and haptoglobin respectively. The rates at which the proteins were externalized after the lag period were also strongly affected by temperature, the half-time for secretion being 20 min at 37 degrees C and 200 min at 20 degrees C for albumin; at 16 degrees C no secretion could be detected after incubation for 270 min. Analysis by subcellular fractionation showed that part of the lag occurred in the endoplasmic reticulum and that the rate of transfer to the Golgi complex was very temperature-dependent. The maximum amount of the two pulse-labelled proteins in Golgi fractions prepared from cells after different times of chase decreased with decreasing incubation temperatures, indicating that the transport from the Golgi complex to the cell surface was less affected by low temperatures than was the transport from the endoplasmic reticulum to the Golgi complex.

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WHAT THIS PAPER ADDS Masseter muscle area (MA) can be measured reliably from pre-operative computed tomography angiography and is a significant predictor of long-term mortality after carotid endarterectomy, independent of other risk factors, anthropometric measures, and dental status. To understand its potential in risk stratification and longterm mortality, the results need to be validated in independent cohorts and studies powered to stratify for different indication categories. Objective/Background: Sarcopenia is a predictor of mortality in elderly patients. Masseter area (MA) reflects sarcopenia in trauma patients. It was hypothesised that MA and Masseter density (MD) could be evaluated reliably from pre-operative computed tomography angiography (CTA) scans and that they predict postoperative survival in carotid endarterectomy (CEA) patients. Methods: This was an observational registry study. Patients (n ¼ 242) were operated on for asymptomatic stenosis (n ¼ 32; 13.2%), amaurosis fugax (n ¼ 41; 16.9%), transient ischaemic attack (n ¼ 85; 35.1%), or ischaemic stroke (n ¼ 84; 34.7%). Internal carotid artery stenoses were graded angiographically. Intraclass correlation coefficient (ICC) was used to analyse measurement reliability by three independent observers. Cox regression analysis was used to study the effect of MA and MD on survival (hazard ratio [HR]). Results: Median patient age was 71.0 years (interquartile range [IQR] 13.0) and follow up time was 68.5 months (range 3e163 months); at the end of follow up (1 October 2017), 104 (43.0%) patients had died according to the National Population Register. The average MA (MAavg, the mean of left and right MA [median 394.0 mm 2 ; IQR 110.1 mm 2 ]) and MD (MDavg, the mean of left and right MD [median 53.5 HU; IQR 16.5 HU]) could be measured with excellent reliability (ICC > 0.865, p < .001 for all). In multivariable analyses only body surface area (BSA) (p < .001) and dental status were associated with MAavg (p ¼ .021). Increased MAavg predicted lower mortality (HR 0.76, 95% confidence interval [CI] 0.61e0.96; p ¼ .023) independent of age (HR 1.05, 95% CI 1.02e1.07; p ¼ 0.001), female sex, body mass index, renal insufficiency, ipsilateral stenosis, indication category, and presence of teeth. MDavg was not associated with mortality. After further adjustment, BSA (the most significant determinant of MAavg) did not alter the association between MAavg and mortality (0.75, 95% CI 0.58e0.97; p ¼ .031). Conclusion: Average MA but not MD measured from the pre-operative CTA scan provides a reliable estimate of post-operative long-term survival in CEA patients independent of other risk factors, anthropometric measurements, and dental status.

BackgroundBrain atrophy is associated with an inferior functional outcome in patients undergoing mechanical thrombectomy (MT) for acute ischemic stroke. We hypothesized that brain atrophy determined from pre-interventional non-contrast-enhanced CT scans would also be linked to increased mortality in this cohort.MethodsA total of 204 patients treated with MT for acute occlusions of the internal carotid artery (ICA) or the M1 segment of the middle cerebral artery (M1) at Tampere University Hospital, Finland between 2013 and 2017 were retrospectively studied. Brain atrophy index (BAI), masseter muscle surface area and density, chronic ischemic lesions, and white matter lesions were evaluated from pre-interventional CT studies. Logistic regression was applied in analyzing the association of BAI with 3-month mortality.ResultsMedian age at baseline was 69.9 years (IQR 15.6) and mortality at 3 months was 13.2% (n=27). BAI, measured with excellent reproducibility (intraclass correlation coefficient ≥0.894, p<0.001), was significantly associated with age (r=0.54), white matter lesions (r=0.43), dental status (r=−0.31), masseter area (r=−0.24), masseter density (r=−0.28), and chronic ischemic lesions (r=0.24) (p≤0.001 for all). In univariable analysis, BAI demonstrated a strong association with mortality (OR 2.02, 95% CI 1.34 to 3.05, per 1 SD increase), and none of the other factors associated with mortality remained as significant when included in the same multivariable model. The results remained similar when extending the follow-up up to 2.5 years.ConclusionsBrain atrophy predicts 3-month mortality after MT of the ICA or the M1 independent of age, masseter sarcopenia, chronic ischemic lesions, or white matter lesions.

BackgroundMasseter area (MA), a surrogate for sarcopenia, appears to be useful when estimating postoperative survival, but there is lack of consensus regarding the potential predictive value of sarcopenia in acute ischemic stroke (AIS) patients. We hypothesized that MA and density (MD) evaluated from pre-interventional CT angiography scans predict postinterventional survival in patients undergoing mechanical thrombectomy (MT).Materials and methods312 patients treated with MT for acute occlusions of the internal carotid artery (ICA) or the M1 segment of the middle cerebral artery (M1-MCA) between 2013 and 2018. Median follow-up was 27.4 months (range 0–70.4). Binary logistic (alive at 3 months, OR <1) and Cox regression analyses were used to study the effect of MA and MD averages (MAavg and MDavg) on survival.ResultsIn Kaplan–Meier analysis, there was a significant inverse relationship with both MDavg and MAavg and mortality (MDavg P<0.001, MAavg P=0.002). Long-term mortality was 19.6% (n=61) and 3-month mortality 12.2% (n=38). In multivariable logistic regression analysis at 3 months, per 1-SD increase MDavg (OR 0.61, 95% CI 0.41 to 0.92, P=0.018:) and MAavg (OR 0.57, 95% CI 0.35 to 0.91, P=0.019) were the independent predictors associated with lower mortality. In Cox regression analysis, MDavg and MAavg were not associated with long-term survival.ConclusionsIn acute ischemic stroke patients, MDavg and MAavg are independent predictors of 3-month survival after MT of the ICA or M1-MCA. A 1-SD increase in MDavg and MAavg was associated with a 39%–43% decrease in the probability of death during the first 3 months after MT.