Masaru Honda

Adrenomedullin Improves the Blood–Brain Barrier Function Through the Expression of Claudin-5

Summary1. Aims: Brain vascular endothelial cells secret Adrenomedullin (AM) has multifunctional biological properties. AM affects cerebral blood flow and blood–brain barrier (BBB) function. We studied the role of AM on the permeability and tight junction proteins of brain microvascular endothelial cells (BMEC).2. Methods: BMEC were isolated from rats and a BBB in vitro model was generated. The barrier functions were studied by measuring the transendothelial electrical resistance (TEER) and the permeability of sodium fluorescein and Evans’ blue albumin. The expressions of tight junction proteins were analyzed using immunocytochemistry and immunoblotting.3. Results: AM increased TEER of BMEC monolayer dose-dependently. Immunocytochemistry revealed that AM enhanced the claudin-5 expression at a cell–cell contact site in a dose-dependent manner. Immunoblotting also showed an overexpression of claudin-5 in AM exposure.4.Conclusions: AM therefore inhibits the paracellular transport in a BBB in vitro model through claudin-5 overexpression.

High-resolution magnetic resonance imaging for detection of carotid plaques.

OBJECTIVE: We report our experience using high-resolution magnetic resonance imaging (MRI) to identify carotid plaques and also discuss these MRI findings while comparing them with carotid endarterectomy specimens. METHODS: Eighteen carotid plaques from 17 different patients were observed using plaque MRI. The patients included 14 men and 3 women, aged 53 to 75 years (mean, 68.6 yr). Eight patients experienced a stroke and four patients experienced transient ischemic attack. The remaining five patients did not experience any neurological symptoms. Two-dimensional time-of-flight (TOF) MR angiography; T1-weighted imaging; fat-suppressed, cardiac gated, black-blood proton density imaging; and T2-weighted imaging were obtained with a 1.5-T MRI. RESULTS: Symptomatic plaques showed either vast or partially dotted high signals for each contrast. The high signal intensity on time-of-flight and T2-weighted imaging predicted the instability of the plaques (100% sensitivity and specificity). In particular, time-of-flight imaging predicted intraplaque hemorrhaging with 100% sensitivity and 80% specificity. MRI revealed that three of four asymptomatic lesions were unstable plaques. CONCLUSION: High-resolution MRI was able to detect various signal patterns related to the plaque components, and it was thus considered to be very useful for evaluating plaque instability. The application of plaque MRI therefore may positively affect the decision-making process when selecting optimal therapeutic strategies to treat with carotid plaques.

Congenital cavernous angioma of the temporal bone: case report

BACKGROUND Congenital cavernous angioma is a very rare tumor that occurs in young adolescents. We describe a rare case of congenital cavernous angioma of the temporal bone in a neonate. Ultrasonography (US) and dynamic magnetic resonance imaging (MRI) were helpful in its diagnosis. CASE DESCRIPTION US and MRI of the fetus in the 32nd week of gestation revealed a large extra-axial tumor with intra- and extracranial extension. After the birth, US and dynamic MRI studies were performed in addition to conventional CT and MRI. These findings were compatible with cavernous angioma. The mass was totally removed on the fourth day of life and was found at surgery to originate from the skull. Histopathological diagnosis was cavernous angioma. The usefulness of US and dynamic MRI are also discussed. CONCLUSION US and dynamic MRI are useful, less invasive techniques for diagnosing this rare type of tumor. They provide useful information to differentiate calvarial mass lesions in neonates.

Massive intratumoral hemorrhage of ependymoma of the fourth ventricle.

IntroductionEpendymomas of the fourth ventricle usually show slowly progressive neurological deterioration and acute onset resulting from major intratumoral bleeding is very rare.Case reportA 16-month-old girl, previously in good health, showed gradual gait disturbance and appetite loss. She was transferred to our hospital because of a large enhanced tumor of the fourth ventricle with mild hydrocephalus. She suddenly lost consciousness on the next day. A computed tomography showed massive intratumoral hemorrhage and acute hydrocephalus. Emergency tumor removal was performed. Histopathological diagnosis was ependymoma.Discussion We speculated the mechanism of intratumoral hemorrhage in posterior fossa ependymomas.

Intracranial internal carotid artery stenosis with vulnerable plaques successfully treated by stenting under cerebral protection.

Percutaneous transluminal angioplasty with stenting (PTA/stenting) for intracranial atherosclerotic stenoses is usually performed without any protection devices. We report a unique case of atherothrombotic stenosis with the vulnerable plaque in the cavernous portion of the internal carotid artery (ICA), which was successfully treated by PTA/stenting under cerebral protection with the flow reversal system. A 68-year-old woman presented repetitive transient ischemic attacks in the right ICA territory. Cerebral angiography revealed 80% stenosis in the cavernous portion of the right ICA. High-resolution magnetic resonance imaging (HR-MRI) demonstrated lipid-rich plaques at this lesion. PTA/stenting was performed with a proximal protection device under flow reversal. A filter device captured much amount of atherothrombotic debris with lipid-rich macrophages and leukocytes, which was consistent with HR-MRI findings. Some selected cases of intracranial atherothrombotic ICA stenoses may need endovascular treatment with cerebral protection system. HR-MRI is useful to evaluate plaque characteristics even in the cavernous portion of the ICA.