Delayed inhibition of c-Jun N-terminal kinase worsens outcomes after focal cerebral ischemia

The stress-activated protein kinase c-Jun N-terminal kinase (JNK) is a central regulator in neuronal death cascades. In animal models of cerebral ischemia, acute inhibition of JNK reduces infarction and improves outcomes. Recently however, emerging data suggest that many neuronal death mediators may have biphasic properties-deleterious in the acute stage but potentially beneficial in the delayed stage. Here, we hypothesized that JNK may also have biphasic actions, so some caution may be required in the development of JNK inhibitors for stroke. Sprague Dawley rats underwent 90 min transient occlusions of the middle cerebral artery. Acute treatment (10 min poststroke) with the JNK inhibitor SP600125 reduced infarction volumes. In contrast, delayed treatment (7 d poststroke) worsened infarction volumes and neurological outcomes. Immunostaining of peri-infarct cortex showed that JNK inhibition suppressed surrogate markers of neurovascular remodeling, including matrix metalloproteinase-9 in GFAP-positive astrocytes and microvascular density. Consistent with these in vivo data, SP600125 significantly suppressed in vitro angiogenesis in rat brain endothelial cultures. Our data provide initial proof-of-concept that the neuronal death target JNK may also participate in endogenous processes of neurovascular remodeling and recovery after cerebral ischemia.     

Criteria for the diagnosis of idiopathic pleuroparenchymal fibroelastosis: A proposal

BackgroundPhysicians have few opportunities to perform surgical lung biopsy (SLB) to diagnose idiopathic pleuroparenchymal fibroelastosis (IPPFE). Therefore, diagnostic criteria for IPPFE that do not require SLB must be established. Herein, we propose diagnostic criteria for IPPFE with and without SLB.Methods and resultsThe diagnostic criteria for IPPFE with SLB are histological, based on computed tomography (CT) lesions compatible with PPFE, predominantly in the upper lobes. The three diagnostic criteria for IPPFE without SLB are as follows: (1) radiologically possible IPPFE (a radiological criterion confirming CT lesions in both lung apexes, regardless of the lower lobe lesions); (2) radiologically probable IPPFE (also a radiological criterion, but mandatory to confirm chest radiograph findings of bilateral upward shift of the hilar structures and/or CT findings of volume loss of the upper lobes); (3) radiologically and physiologically probable IPPFE. Our data from 41 patients with IPPFE and 97 with idiopathic pulmonary fibrosis (IPF) showed that the percentage of the predicted values of the ratio of residual volume to total lung capacity (RV/TLC %pred.) ≥115% and body mass index (BMI) ≤20 kg/m² plus RV/TLC %pred. ≥80% performed well for discriminating IPPFE from IPF. These parameters were thus added to criterion (3).ConclusionsWe have proposed diagnostic criteria for IPPFE in patients with and without SLB. Both imaging criteria and physiological criteria using RV/TLC and BMI successfully discriminate IPPFE from chronic IIPs when SLB cannot be performed.     

Three-dimensional quantitation of regional cerebral blood flow in mice using a high-resolution pinhole SPECT system and 123I-iodoamphetamine

Introduction

This study is intended to evaluate the feasibility of using a high-resolution pinhole SPECT system and iodine-123-N-isopropyl-4-iodoamphetamine (¹²³I-IMP) for three-dimensional (3D) absolute quantitation of regional cerebral blood flow (rCBF) in mice.

Methods

The pinhole SPECT system consists of a rotating stage and a pinhole collimator attached to a clinical gamma camera. The collimator's focal length is 251 mm. Phantom studies were performed to evaluate sensitivity and full-width half-maximum (FWHM) spatial resolution. The aperture-to-object distance was 15 mm. Six mice were studied. Cerebral infarctions were induced by ligating and disconnecting the distal portion of the left middle cerebral artery. Ex vivo SPECT studies were performed using harvested brains and skulls. The CBF volumetric image was computed using the standardized input function.

Results

Excellent spatial resolution of 0.9-mm FWHM and uniform sensitivity throughout the 3D volume were demonstrated in the phantom experiments. The CBF images showed a defect in the infarcted areas and a reduction of CBF values in the infarcted region as compared with the control region.

Conclusions

This study demonstrated the feasibility of the 3D quantitation of rCBF in mice using a high-resolution pinhole SPECT system and ¹²³I-IMP.     

Atrial fibrillation is a major risk factor for stroke, especially in women: the Jichi Medical School cohort study

Background

Only a few population-based cohort studies have investigated the impact of atrial fibrillation (AF) on stroke in Japan.

Methods

A total of 10 929 participants (4147 men and 6782 women) were included in this population-based prospective cohort study. Baseline data, including electrocardiograms (ECGs) to ascertain AF status, were obtained from April 1992 through July 1995 in 12 areas in Japan. Cox proportional hazards models were used to analyze the association of AF with stroke.

Results

A total of 54 participants had AF (0.49%). The mean follow-up period was 10.7 years, during which 405 strokes were identified; 12 of these occurred in participants with AF. The crude incidence of stroke in participants with and without AF was 14.9 and 4.5 per 1000 person-years in men, respectively, and 39.3 and 2.7 per 1000 person-years in women. After adjusting for geographical area, sex, age, smoking status, drinking status, obesity, hypertension, dyslipidemia, and diabetes mellitus, the hazard ratios (95% confidence interval) of AF in all participants and in male and female participants were 4.11 (2.28–7.41), 2.12 (0.77–5.84), and 10.6 (5.01–22.4), respectively. The population attributable fraction (PAF) of stroke caused by AF was 2.2%; the PAFs were 1.0% and 3.6% in men and women, respectively.

Conclusions

The present Japanese population-based prospective cohort study showed that AF is a major risk factor for stroke, especially in women.Key words: atrial fibrillation, stroke, women, cohort study     

Validity of predictive equations for basal metabolic rate in Japanese adults

Many predictive equations for basal metabolic rate (BMR) based on anthropometric measurements, age, and sex have been developed, mainly for healthy Caucasians. However, it has been reported that many of these equations, used widely, overestimate BMR not only for Asians, but also for Caucasians. The present study examined the accuracy of several predictive equations for BMR in Japanese subjects. In 365 healthy Japanese male and female subjects, aged 18 to 79 y, BMR was measured in the post-absorptive state using a mask and Douglas bag. Six predictive equations were examined. Total error was used as an index of the accuracy of each equation's prediction. Predicted BMR values by Dietary Reference Intakes for Japanese (Japan-DRI), Adjusted Dietary Reference Intakes for Japanese (Adjusted-DRI), and Ganpule equations were not significantly different from the measured BMR in either sex. On the other hand, Harris-Benedict, Schofield, and Food and Agriculture Organization of the United Nations/World Health Organization/United Nations University equations were significantly higher than the measured BMR in both sexes. The prediction error by Japan-DRI, Adjusted-DRI, and Harris-Benedict equations was significantly correlated with body weight in both sexes. Total error using the Ganpule equation was low in both males and females (125 and 99 kcal/d, respectively). In addition, total error using the Adjusted-DRI equation was low in females (95 kcal/d). Thus, the Ganpule equation was the most accurate in predicting BMR in our healthy Japanese subjects, because the difference between the predicted and measured BMR was relatively small, and body weight had no effect on the prediction error.     

Vitamin E-deficiency did not exacerbate partial skin reactions in mice locally irradiated with X-rays

We previously showed that free radicals and oxidative stress are involved in radiation-induced skin reactions. Since vitamin E (VE) is a particularly important lipophilic antioxidant, VE-deficient mice were used to examine its effects on radiation-induced skin damage. The VE content of the skin was reduced to one fourth of levels of normal mice. Neither the time of onset nor the extent of the reactions quantified with a scoring system differed between normal and VE-deficient mice after local X-irradiation (50 Gy). Similarly, there was no difference in the levels of the ascorbyl radical between the groups, although they were higher in irradiated skin than non-irradiated skin. X-irradiation increased the amount of Bax protein in the skin of normal mice both in the latent and acute inflammatory stages, time- and dose-dependently. The increase was associated with an increase in cytochrome c in the cytosolic fraction, indicating that apoptosis was also promoted by the irradiation. The increase in Bax protein correlated well with the thickness of the skin. Although a deficiency in VE should lower resistance to free radicals in the mitochondrial membrane and thus enhance radiation-induced Bax expression and apoptosis, it actually attenuated the increase in Bax protein caused by irradiation.