Increased brachial-ankle pulse wave velocity is independently associated with white matter hyperintensities.

BACKGROUND: White matter hyperintensities (WMHs) are a risk factor for stroke. Their etiology is considered to be cerebral microvascular abnormality. However, the association between WMHs and arteriosclerosis is not yet clear. The aim of this hospital-based cohort study was to identify the arteriosclerotic characteristics associated with WMHs. METHODS: We cross-sectionally included 240 consecutive patients with no history of stroke. We measured the brachial-ankle pulse wave velocity (baPWV), ankle brachial pressure index, and intima-media thickness of the common carotid artery, and we performed magnetic resonance brain imaging. WMHs were defined as periventricular hyperintensity (Fazekas grade ≥3) and/or separate deep white matter hyperintense signals (Fazekas grade ≥2). We determined the prevalence of WMHs, silent brain infarction (SBI), hypertension, hypercholesterolemia, diabetes mellitus, ischemic heart disease, and smoking. We compared 2 groups of patients, defined by the presence or absence of WMHs, using multiple logistic regression analyses. RESULTS: In multivariable analysis, SBI (OR 3.38; 95% CI 1.52-7.72), hypertension (OR 2.23; 95% CI 1.03-5.15), female sex (OR 1.95; 95% CI 1.03-3.76), baPWV (OR 1.12; 95% CI 1.02-1.23), and age (OR 1.09; 95% CI 1.04-1.14) were independently associated with WMHs. CONCLUSIONS: An increased baPWV is associated with WMHs. Management of increased baPWV may help to prevent the progression of WMHs and stroke.

Clinical features of a first-ever lacunar infarction in Japanese patients: poor outcome in females.

Lacunar infarction (LI) remains an important stroke subtype in Japan. The aim of this study was to investigate the characteristics of outcome determinants in LI. This study was a single center observational study and included 163 consecutive patients (108 male, 55 female; mean age 69 years). The National Institutes of Health Stroke Scale (NIHSS) score on admission and the modified Rankin scale (mRS) score at discharge were used to evaluate stroke severity. We determined the location of the infarct, the grade of white matter hyperintensity (WMH), and the prevalence of silent brain infarcts, hypertension, hypercholesterolemia, diabetes mellitus, ischemic heart disease, and smoking. We compared 2 groups, good outcome (mRS score 0-2) and poor outcome (mRS score 3-5), using multiple logistic regression analysis. We found significant differences between the 2 groups according to female sex (P = .04), WMH (P = .04), and NIHSS score (P < .001). After multivariate analysis, female sex (odds ratio [OR] = 3.4, 95% confidence interval [CI] = 1.1-11.4; P = .03), and NIHSS score (OR = 2.3, 95% CI = 1.7-3.3; P < .001) were independently associated with poor outcome. Elderly onset, poor outcome, and hypercholesterolemia were more common in female patients, whereas smoking was more prevalent in males. Our data indicate that sex differences exist in Japanese LI patients with regard to risk factors and outcome. The treatment of risk factors based on sex differences is important to the management of LI.

Congenital semilunar valvulogenesis defect in mice deficient in phospholipase C epsilon.

Phospholipase Cepsilon is a novel class of phosphoinositide-specific phospholipase C, identified as a downstream effector of Ras and Rap small GTPases. We report here the first genetic analysis of its physiological function with mice whose phospholipase Cepsilon is catalytically inactivated by gene targeting. The hearts of mice homozygous for the targeted allele develop congenital malformations of both the aortic and pulmonary valves, which cause a moderate to severe degree of regurgitation with mild stenosis and result in ventricular dilation. The malformation involves marked thickening of the valve leaflets, which seems to be caused by a defect in valve remodeling at the late stages of semilunar valvulogenesis. This phenotype has a remarkable resemblance to that of mice carrying an attenuated epidermal growth factor receptor or deficient in heparin-binding epidermal growth factor-like growth factor. Smad1/5/8, which is implicated in proliferation of the valve cells downstream of bone morphogenetic protein, shows aberrant activation at the margin of the developing semilunar valve tissues in embryos deficient in phospholipase Cepsilon. These results suggest a crucial role of phospholipase Cepsilon downstream of the epidermal growth factor receptor in controlling semilunar valvulogenesis through inhibition of bone morphogenetic protein signaling.

[Adult case of acute encephalopathy associated with bilateral thalamic lesions and peripheral neuropathy].

A 76-year-old woman developed fever and consciousness disturbance. The next day, she became delirious and was brought to our hospital. On arrival, she was unconscious and showed hypopnea and hypotension. She was immediately intubated and placed on a respirator. CSF protein was 65.8 mg/dl with 1 cell/microl, and no oligoclonal bands were present. An electroencephalogram showed diffuse theta background activity without epileptic discharges. A nerve conduction study showed damaged motor and sensory peripheral nerve functions in the upper and lower limbs. The neurological findings showed no improvement after methylprednisolone pulse therapy and administration of intravenous immunoglobulin. Magnetic resonance imaging of the brain, including diffusion-weighted images showed bilateral symmetric lesions in the thalamus, globus pallidus and pontine tegmentum. These radiologic findings are not typically, but are similar to those of acute necrotizing encephalopathy (ANE) of childhood as proposed by Mizuguchi et al. After 10 months, brain MRI showed bilateral brain atrophy and a reduction of the abnormal thalamic lesions. There are very few reports of adult cases of ANE, in which, pathologically, local breakdown of the blood-brain-barrier causes acute edema and necrosis involving both gray and white matter. ANE is thought a proinflammatory cytokine-related disease. In our case, the concentrations of some cytokines (IL-6, IL-10) were elevated in serum and cerebrospinal fluid, which might suggest a relationship with them and local breakdown of the blood-brain-barrier in the thalamus.

Differential roles of Ras and Rap1 in growth factor-dependent activation of phospholipase C epsilon.

Phospholipase C epsilon is a phosphoinositide-specific phospholipase C that selectively associates with Ras and Rap small GTPases as a target. Here we explored the molecular basis of the Rap1- as well as Ras-mediated regulation of phospholipase C epsilon upon platelet-derived growth factor stimulation by using a receptor mutant deficient in its ability to phosphorylate and activate phospholipase C gamma. Following platelet-derived growth factor treatment, this receptor induces persistent activation of ectopically expressed PLC epsilon through activation of Ras and Rap1. The rapid and initial phase of the activation is mediated by Ras, whereas Rap1 is responsible for the prolonged activation. We further demonstrate that the CDC25 homology domain, which exhibits guanine nucleotide exchange factor activity toward Rap1, but not Ras, is critical for the prolonged activation of phospholipase C epsilon. Platelet-derived growth factor prevented the hematopoietic BaF3 cells containing the mutant receptor from undergoing apoptosis, and enabled these cells to proliferate, only when phospholipase C epsilon was expressed. Therefore, the phospholipase C signal is suggested to be critical for survival and growth of BaF3 cells.

[A case of slowly progressive unilateral spastic hemiparasis, hand clumsiness, limb ataxia and constructional apraxia].

A 65-year-old woman was seen in our clinic because of a 4-year history of slowly progressive left hand clumsiness and left limping. Neurologically, she had left-side spastic hemiparasis including her tongue, hand clumsiness, limb ataxia, constructional apraxia, and memory impairment. Dementia, parkinsonism and lower motor neuron sign were not confirmed. MRI study showed diffuse cerebral atrophy and shrinkage of the right cerebral peduncle and pontine base. SPECT (99mTc-ECD) study revealed hypoperfusion of the right fronto-parietal cortex. This is a rare case presented with slowly progressive left-side spastic hemiparasis, mimicking Mills' syndrome. In addition this case had other cortical signs, such as ipsilateral hand clumsiness, limb ataxia, constructional apraxia. Neuroimaging study suspects that the right front-parietal cortex is the primary lesion. Etiologically atypical motor neuron disease with adjacent cortical involvement is suspected rather than corticobasal degeneration with severe unilateral pyramidal tract degeneration.

Late-onset CMT2 associated with a novel missense mutation in the cytoplasmic domain of the MPZ gene.

Phenotypic variations have been reported in Charcot-Marie-Tooth disease type 2 (CMT2) including age-at-onset, disease progression and severity. Sporadic cases with CMT2 have also been demonstrated by genetic test. We here report a patient with late-onset CMT2 without family history, who developed gait disturbance at the age of 68. Sequence analysis revealed a novel heterozygous Arg198Gly mutation in the cytoplasmic domain of the major peripheral myelin protein zero (MPZ). The mutation is located in the protein kinase C (PKC) alpha substrate motif (RSTK) of MPZ, presumably leading to the loss of PKC-mediated phosphorylation in adhesion. Routine genetic test for CMT is not recommended for every patient with late-onset peripheral neuropathy without known causes, however, the genetic test may be taken into consideration if the patient shows a clinical phenotype similar to that of CMT, and the possibility of a de novo mutation cannot be excluded.

Re-evaluation of clinical features and risk factors of acute ischemic stroke in Japanese longevity society.

Age is an important factor correlated with stroke prevalence and independently influences stroke outcome especially in Japanese longevity society. To re-evaluate the characteristics of acute ischemic stroke in the old-old, analyses of clinical data on 426 patients registered at a Japanese tertiary emergency hospital were performed under appropriate statistical methods. Clinical features, stroke subtypes, current-known risk factors for stroke, time from onset to arrival, the National Institute of Health Stroke scale (NIHSS) score on admission, length of hospital stay, modified Rankin Scale (mRS) at discharge were compared between two stratified groups by age-at-onset (≧75 and < 75 years old). Significant differences were demonstrated in categories of sex, NIHSS score, length of hospital stay and m-RS. Current-known risk factors for stroke except atrial fibrillation were not prominent in the elderly group. Our study revealed that clinical phenotype and outcome in stroke patients would have been modified and re-evaluation of risk factors is necessary for prevention of ischemic stroke in Japanese longevity society.

[A case of brainstem encephalitis following multiple cranial neuropathy in a hepatocellular carcinoma patient--association with cytomegalovirus and varicella-zoster virus infection].

A 72-year-old male with liver cirrhosis and hepatocellular carcinoma experienced general fatigue. Four days later he was admitted to our hospital because of dizziness, dysbasia and left facial palsy (day 1). On day 6, a neurological examination revealed left trigeminal neuralgia, left medial longitudinal fasciculus (MLF) syndrome, skew deviation, hypacusia, tongue deviation and left limb ataxia. Magnetic resonance imaging of the brain including diffusion-weighted imaging showed previous lacunar infarctions at the left thalamus and pons. The immunological investigation for viral infection in his serum samples showed high titers of IgM antibody against cytomegalovirus (CMV). Cerebrospinal fluid (CSF) investigation revealed mononuclear pleocytosis, elevated protein levels and high titers of IgG antibody against the varicella-zoster virus (VZV). Anti-CMV antibody measurement and CMV-DNA detection by the polymerase chain reaction in CSF revealed that the central nervous system (CNS) was not infected by CMV. We diagnosed this case as brainstem encephalitis following multiple cranial neuropathy associated with CMV and VZV infections. The neurological symptoms gradually improved with aciclovir and prednisolone therapy. The titers of antibody for CMV in his serum samples normalized 4 months later after onset. Although there was no evidence of CMV infection in the CNS was obtained, parainfection or autoimmune mediated responses followed by viral infections might have led to brainstem encephalitis with multiple cranial nerve involvements in our patient.

Genes from Pseudomonas sp. strain BS involved in the conversion of L-2-amino-Delta(2)-thiazolin-4-carbonic acid to L-cysteine.

DL-2-amino-Delta(2)-thiazolin-4-carbonic acid (DL-ATC) is a substrate for cysteine synthesis in some bacteria, and this bioconversion has been utilized for cysteine production in industry. We cloned a DNA fragment containing the genes involved in the conversion of L-ATC to L-cysteine from Pseudomonas sp. strain BS. The introduction of this DNA fragment into Escherichia coli cells enabled them to convert L-ATC to cysteine via N-carbamyl-L-cysteine (L-NCC) as an intermediate. The smallest recombinant plasmid, designated pTK10, contained a 2.6-kb insert DNA fragment that has L-cysteine synthetic activity. The nucleotide sequence of the insert DNA revealed that two open reading frames (ORFs) encoding proteins with molecular masses of 19.5 and 44.7 kDa were involved in the L-cysteine synthesis from DL-ATC. These ORFs were designated atcB and atcC, respectively, and their gene products were identified by overproduction of proteins encoded in each ORF and by the maxicell method. The functions of these gene products were examined using extracts of E. coli cells carrying deletion derivatives of pTK10. The results indicate that atcB and atcC are involved in the conversion of L-ATC to L-NCC and the conversion of L-NCC to cysteine, respectively. atcB was first identified as a gene encoding an enzyme that catalyzes thiazolin ring opening. AtcC is highly homologous with L-N-carbamoylases. Since both enzymes can only catalyze the L-specific conversion from L-ATC to L-NCC or L-NCC to L-cysteine, it is thought that atcB and atcC encode L-ATC hydrolase and N-carbamyl-L-cysteine amidohydrolase, respectively.

Neuronal lineage-specific induction of phospholipase Cepsilon expression in the developing mouse brain.

Phospholipase C is a key enzyme of intracellular signal transduction in the central nervous system. We and others recently discovered a novel class of phospholipase C, phospholipase Cepsilon, which is regulated by Ras and Rap small GTPases. As a first step toward analysis of its function, we have examined the spatial and temporal expression patterns of phospholipase Cepsilon during mouse development by in situ hybridization and immunohistochemistry. Around embryonic day 10.5, abundant expression of phospholipase Cepsilon is observed specifically in the outermost layer of the neural tube. On embryonic day 12 and later, it is observed mainly in the marginal zone of developing brain and spinal cord as well as in other regions undergoing neuronal differentiation, such as the retina and olfactory epithelium. The phospholipase Cepsilon-expressing cells almost invariably express microtubule-associated protein 2, but hardly express nestin or glial fibrillary acidic protein, indicating that the expression of phospholipase Cepsilon is induced specifically in cells committed to the neuronal lineage. The expression of phospholipase Cepsilon persists in the terminally differentiated neurons and exhibits no regional specificity. Further, an in vitro culture system of neuroepithelial stem cells is employed to show that abundant expression of phospholipase Cepsilon occurs in parallel with the loss of nestin expression as well as with the induction of microtubule-associated protein 2 expression and neuronal morphology. Also, glial fibrillary acidic protein-positive glial lineage cells do not exhibit the high phospholipase Cepsilon expression. These results suggest that the induction of phospholipase Cepsilon expression may be a specific event associated with the commitment of the neural precursor cells to the neuronal lineage.