Variant Type of Posterior Reversible Encephalopathy Syndrome Associated with Deep Brain Hemorrhage: Case Report and Review of the Literature.

BACKGROUND: Various radiologic patterns of posterior reversible encephalopathy syndrome (PRES) have been reported. Among them, PRES involving brainstem, thalamus, or deep white matter and lacking parieto-occipital edema is rare. Although PRES in general has a benign course, PRES-related intracranial hemorrhage has been associated with a poor prognosis. We report a case of variant type of PRES associated with deep brain hemorrhage and discuss the characteristics of PRES-related intracranial hemorrhage via a literature review. CASE DESCRIPTION: A woman aged 41 years with a history of untreated hypertension presented to our hospital complaining of severe headache and with an elevated blood pressure of 237/142 mmHg. Computed tomography revealed a hemorrhage in the left thalamus and basal ganglia. Magnetic resonance imaging revealed remarkable hyperintensity in the left cerebellum, pons, bilateral temporal lobes, bilateral basal ganglia, and bilateral cerebral white matter on fluid-attenuated inversion recovery imaging, which represented vasogenic edema. The parieto-occipital regions were unremarkable. Given this clinical presentation, PRES associated with deep brain hemorrhage was suspected. The patient received strict blood pressure control treatment, which resulted in gradual symptom improvement. Magnetic resonance images obtained 1 month after admission demonstrated an almost complete resolution of the edema. CONCLUSIONS: Although hemorrhage in the thalamus, basal ganglia, or brainstem is uncommon in patients with PRES, it may occur in patients with variant type of PRES involving these lesions. It is important to recognize the presence of variant patterns of clinical features and radiologic findings of PRES to allow for early identification and appropriate treatment.

[Two cases of anterior cerebral artery aneurysm associated with accessory anterior cerebral artery: review of the literature and points of diagnosis].

The accessory anterior cerebral artery (AccACA) is an anomalous vessel arising from the anterior communicating artery. Although AccACA is not particularly rare, aneurysms arising from the AccACA is extremely rare. Here, we report two cases of unruptured AccACA aneurysms. Patient 1 was a 58-year-old woman with an unruptured distal AccACA aneurysm. Magnetic resonance imaging and three-dimensional computed tomography angiography(3D-CTA)demonstrated a left middle cerebral artery aneurysm that was subsequently clipped successfully by direct surgery. No aneurysm was detected in the distal anterior cerebral artery(ACA)due to the narrow imaging range at that time. Postoperatively, an aneurysm of the distal ACA was incidentally identified on 3D-CTA. This AccACA aneurysm was also clipped by direct surgery about 5 months later, and the patient was discharged without any neurological deficits. Patient 2 was a 46-year-old woman with an aneurysm at the proximal portion of the AccACA. Since the aneurysm was small and patient was asymptomatic, the observation-approach was selected. In introducing these cases, we discuss AccACA aneurysms and the process of diagnosis. Aneurysm can arise over the entire length of the ACA, from the anterior communicating artery to the peripheral portion, particularly the supracallosal portion, so observation and imaging of the peripheral region is important in cases where an AccACA is present.

Coil embolization for a ruptured posterior cerebral artery aneurysm with vertebrobasilar dolichoectasia.

A 74-year-old man suffered sudden loss of consciousness at home. Computed tomography revealed severe subarachnoid hemorrhage and an unusual posterior cerebral artery (PCA) aneurysm with vertebrobasilar dolichoectasia (VBD). The aneurysm was located in the right hypothalamus. VBD associated with a distal lesion makes endovascular treatment difficult because of the elongation and tortuosity of the access route. However, endovascular coil embolization was successful for the present ruptured PCA aneurysm with VBD.

[Coil embolization of a ruptured posterior cerebral artery aneurysm via the internal carotid artery and a posterior communicating artery: a case report].

A posterior cerebral artery aneurysm is a rare condition. Various surgical approaches have to be considered for operating on these aneurysms because the position of the aneurysm and the surrounding structures restrict the operative field and render the operation difficult. Recently, endovascular treatments for posterior cerebral artery aneurysms have been reported to provide a good outcome. We present a case of a ruptured posterior cerebral artery aneurysm treated with coil embolization. We adopted endovascular treatment because a large vein of Labbé was expected to restrict the operative field. The internal carotid artery and a fetal-type posterior communicating artery (PCoA) were chosen as the access route because of P1 hypoplasty, and a coaxial guiding system was used because of the tortuous access route. The aneurysm was suitably embolized using Guglielmi detachable coils (GDCs). In a case of posterior cerebral artery aneurysm, we report the usefulness of endovascular treatment performed through the internal carotid artery and a fetal-type PCoA.

Enhanced contractile response of the basilar artery to platelet-derived growth factor in subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The level of platelet-derived growth factor (PDGF) in cerebrospinal fluid is elevated in subarachnoid hemorrhage (SAH). Therefore, the contractile effect of PDGF on the basilar artery was examined in SAH. METHODS: A rabbit double-hemorrhage SAH model was used. In the medial layers of the control basilar artery, PDGF had no effect on contraction up to 1 nmol/L, whereas 3 nmol/L PDGF induced slight contraction. In SAH, PDGF induced an enhanced contraction with an increase in [Ca(2+)](i) at 1 nmol/L and higher concentrations. The levels of [Ca(2+)](i) and tension induced by 1 nmol/L PDGF in SAH were 17% and 20%, respectively, of those obtained with 118 mmol/L K(+) depolarization. The PDGF-induced elevation of [Ca(2+)](i) and contraction seen in SAH were abolished in the absence of extracellular Ca(2+). In alpha-toxin-permeabilized strips of SAH animals, PDGF induced no further development of tension during contraction induced by 300 nmol/L Ca(2+), suggesting no direct effect on myofilament Ca(2+) sensitivity. Genistein at 10 micromol/L completely inhibited the tension induced by 1 nmol/L PDGF. The level of myosin light-chain phosphorylation was significantly increased by 1 nmol/L PDGF. CONCLUSIONS: These results show that the contractile response to PDGF of the basilar artery was enhanced in SAH. The PDGF-induced contraction depended mostly on tyrosine phosphorylation and Ca(2+)-dependent myosin light-chain phosphorylation. The enhancement of the responsiveness to PDGF may therefore contribute to the development of cerebral vasospasm after SAH.

Basic and translational research on proteinase-activated receptors: the role of thrombin receptor in cerebral vasospasm in subarachnoid hemorrhage.

Cerebral vasospasm is one of the major complications of subarachnoid hemorrhage (SAH). The prevention and treatment of cerebral vasospasm thus plays a critical role in the management of SAH patients. However, the mechanism of cerebral vasospasm still remains elusive, while effective therapeutic strategies also remain to be established. The role of thrombin and its receptor proteinase-activated receptor 1 (PAR(1)) in cerebral vasospasm was investigated using a rabbit double hemorrhage SAH model. The expression of PAR(1) was up-regulated and the contractile response to thrombin was markedly enhanced in the basilar artery of SAH models. The intrathecal administration of a PAR(1) antagonist prevented the up-regulation of PAR(1) and the enhancement of the contractile responses to thrombin in SAH. These observations thus suggest that PAR(1) may play a pivotal role in post-hemorrhagic cerebral vasospasm in SAH. Following SAH, thrombin activates PAR(1), thereby up-regulating the expression of PAR(1), which culminates in the increased contractile response to thrombin in the basilar artery. PAR(1) antagonists are thus anticipated to be a novel therapeutic strategy for cerebral vasospasm. However, further studies are needed before establishing the clinical usefulness of PAR(1) antagonists.

Prevention of the hypercontractile response to thrombin by proteinase-activated receptor-1 antagonist in subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Cerebral vasospasm is one of the major complications of subarachnoid hemorrhage (SAH). Its pathogenesis still remains elusive, and effective therapeutic strategies are yet to be established. We investigated the role of proteinase-activated receptor-1 (PAR1) in the hypercontractile state in SAH. METHODS: Rabbit double hemorrhage model was used as a model of SAH. The contractile response to thrombin and the PAR1 expression were evaluated in the isolated rings of basilar artery. RESULTS: Thrombin exhibited only a minor contractile effect in the control, whereas it induced augmented contractions in SAH. The expression of PAR1 was upregulated in SAH. Intracisternal injection of PAR1 antagonist E5555 prevented the enhancement of the contractile responses to thrombin in SAH. The maximal prevention was obtained with 2 microg/kg weight/injection. The contractile responses to K(+) depolarization or endothelin-1 remained unaffected. The upregulation of PAR1 was also prevented by E5555 (2 microg/kg weight/injection) to a level similar to that seen in the control. Ex vivo treatment with E5555 (1 micromol/L) inhibited the contraction induced by thrombin, whereas it had little effect on the contraction induced by K(+) depolarization or endothelin-1, in the basilar artery of SAH. E5555 also inhibited the [Ca(2+)](i) elevation induced by thrombin, but not trypsin, in cultured smooth muscle cells. CONCLUSIONS: PAR1 plays a critical role in upregulating PAR1 itself, thereby enhancing the contractile response to thrombin in SAH. PAR1 could thus be a therapeutic target. However, the usefulness of PAR1 antagonist remains to be investigated in vivo.

Purely cystic form of choroid plexus papilloma with acute hydrocephalus in an infant. Case report.

Infants with acute hydrocephalus often present with nonspecific neurological signs, and cystic choroid plexus papilloma (CPP) is a very rare cause of acute obstructive hydrocephalus. The authors present the case of a 1-year-old girl who became irritable, started vomiting, and became comatose within a day. Magnetic resonance (MR) imaging revealed a cystic lesion in the third ventricle as well as hydrocephalus. Although the aqueduct appeared to be patent, phase-contrast MR imaging showed no pulsatile flow of cerebrospinal fluid in the ventricles. An emergent endoscopic third ventriculostomy was performed. Endoscopic examination revealed a highly mobile cyst attached by a pedicle to the choroid plexus adjacent to the Monro foramen in the lateral ventricle. The cyst was totally excised during the endoscopic procedure and was subsequently diagnosed as a CPP on the basis of histopathological findings. Purely cystic CPP is a very rare pathological entity; however, when it does occur, it can cause obstructive hydrocephalus which, without rapid diagnosis and surgical intervention, could lead to sudden death.

Electrophysiological correlates of associative visual agnosia lesioned in the ventral pathway.

Visual agnosia has been well studied by anatomical, neuropsychological and neuroimaging studies. However, functional changes in the brain have been rarely assessed by electrophysiological methods. We carried out electrophysiological examinations on a 23-year-old man with associative visual agnosia, prosopagnosia and cerebral achromatopsia to evaluate the higher brain dysfunctions of visual recognition. Electrophysiological methods consisted of achromatic, chromatic and category-specific visual evoked potentials (CS-VEPs), and event-related potentials (ERPs) with color and motion discrimination tasks. Brain magnetic resonance imaging revealed large white matter lesions in the bilateral temporo-occipital lobes involving the lingual and fusiform gyri (V4) and inferior longitudinal fasciculi due to multiple sclerosis. Examinations including CS-VEPs demonstrated dysfunctions of face and object perception while sparing semantic word perception after primary visual cortex (V1) in the ventral pathway. ERPs showed abnormal color perception in the ventral pathway with normal motion perception in the dorsal pathway. These electrophysiological findings were consistent with lesions in the ventral pathway that were detected by clinical and neuroimaging findings. Therefore, CS-VEPs and ERPs with color and motion discrimination tasks are useful methods for assessing the functional changes of visual recognition such as visual agnosia.

Endothelial dysfunction and altered bradykinin response due to oxidative stress induced by serum deprivation in the bovine cerebral artery.

Oxidative stress plays a critical role in the pathogenesis of vasospasm after a subarachnoid hemorrhage. We demonstrate that 24-h incubation of the isolated bovine middle cerebral arteries in the serum-free media at 37 degrees C converted the response to bradykinin from relaxation to contraction, in a manner sensitive to free radical scavengers. In the freshly prepared strips, bradykinin induced an endothelium-dependent relaxation, while having no direct effect on the smooth muscle. However, in the strips treated in serum-free media, bradykinin failed to induce endothelium-dependent relaxation, but did demonstrate a direct contractile effect on smooth muscle. The addition of superoxide dismutase and ascorbic acid or 5% serum during the 24-h incubation in the serum-free media prevented the loss of endothelium-dependent relaxation and the development of a contractile response to bradykinin. SB203580 (4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole), a p38 mitogen-activated protein kinase inhibitor, and genistein (4',5,7-Trihydroxyisoflavone), a tyrosine kinase inhibitor, also demonstrated a similar preventive effect. In conclusion, serum-deprivation induced endothelial dysfunction and the responsiveness of smooth muscle to bradykinin due to failure of eliminating oxidative stress. p38 mitogen-activated protein kinase and tyrosine kinase were suggested to play a critical role in this endothelial dysfunction.

Effect of active immunization of pony mares against recombinant porcine inhibin alpha subunit on ovarian follicular development and plasma steroids and gonadotropins.

Two pony mares were immunized against recombinant porcine inhibin alpha subunit three times with 39 day intervals. Clinical findings and endocrinological changes before immunization were taken as the control. The first significant rise in the anti-inhibin titre (P<0.05) in the circulation was found 27 days after the first injection. Maximum binding activity was reached by the 12th day after the second booster dose. The number of small, medium and large sized follicles had increased significantly compared to before immunization (11.75 +/- 4.30, 2.75 +/- 0.69 and 2.51 +/- 0.63 vs 6.50 +/- 1.43, 1.83 +/- 0.44 and 1.33 +/- 0.38, respectively), but the ovulation rate remained unchanged after immunization. The average plasma concentration of FSH and estradiol-17beta during the estrous cycle increased significantly (P<0.05) after immunization. These results suggest that immunization against inhibin is a useful tool to increase the number of ovarian follicles during the estrous cycle of pony mares. Moreover, the present study supported the concept that inhibin plays a major role in the control of follicular growth through its inhibitory effect on FSH secretion synergistically with steroid hormones.

Rho-kinase inhibitor inhibits both myosin phosphorylation-dependent and -independent enhancement of myofilament Ca2+ sensitivity in the bovine middle cerebral artery.

The role of Rho kinase in Ca2+ sensitization of the contractile apparatus in smooth muscle was investigated in the bovine middle cerebral artery. U46619, a thromboxane A2 analog, induced a greater sustained contraction with a smaller [Ca2+]i elevation than that seen with 118 mm K+. The level of myosin light chain (MLC) phosphorylation obtained in the initial phase of the contraction was higher than that seen with 118 mm K+; thereafter, it gradually declined to a comparable level in the late phase. During the steady state of the U46619-induced contraction, Y27632 (10 microM), a Rho-kinase inhibitor, partially inhibited [Ca2+]i, although it substantially inhibited tension and MLC phosphorylation. Wortmannin (10 microM), an MLC kinase inhibitor, had no significant effect on [Ca2+]i, but it completely inhibited MLC phosphorylation and partially inhibited tension. The wortmannin-resistant tension development was thus not associated with MLC phosphorylation, and this component was completely inhibited by Y27632. In conclusion, U46619 enhanced Ca2+ sensitivity in a manner both dependent and independent of MLC phosphorylation in the bovine middle cerebral artery. Both mechanisms of Ca2+ sensitization can be inhibited by the Rho-kinase inhibitor.