Tokutaro Tanaka

The collagen-binding protein of Streptococcus mutans is involved in haemorrhagic stroke

Although several risk factors for stroke have been identified, one-third remain unexplained. Here we show that infection with Streptococcus mutans expressing collagen-binding protein (CBP) is a potential risk factor for haemorrhagic stroke. Infection with serotype k S. mutans, but not a standard strain, aggravates cerebral haemorrhage in mice. Serotype k S. mutans accumulates in the damaged, but not the contralateral hemisphere, indicating an interaction of bacteria with injured blood vessels. The most important factor for high-virulence is expression of CBP, which is a common property of most serotype k strains. The detection frequency of CBP-expressing S. mutans in haemorrhagic stroke patients is significantly higher than in control subjects. Strains isolated from haemorrhagic stroke patients aggravate haemorrhage in a mouse model, indicating that they are haemorrhagic stroke-associated. Administration of recombinant CBP causes aggravation of haemorrhage. Our data suggest that CBP of S. mutans is directly involved in haemorrhagic stroke.

Oral Cnm - positive Streptococcus Mutans Expressing Collagen Binding Activity is a Risk Factor for Cerebral Microbleeds and Cognitive Impairment

Cerebral microbleeds (CMBs) are an important risk factor for stroke and dementia. We have shown that the collagen binding surface Cnm protein expressed on cnm-positive Streptococcus mutans is involved in the development of CMBs. However, whether the collagen binding activity of cnm-positive S. mutans is related to the nature of the CMBs or to cognitive impairment is unclear. Two-hundred seventy nine community residents (70.0 years) were examined for the presence or absence of cnm-positive S. mutans in the saliva by PCR and collagen binding activity, CMBs, and cognitive function were evaluated. Cnm-positive S. mutans was detected more often among subjects with CMBs (pu2009<u20090.01) than those without. The risk of CMBs was significantly higher (odds ratiou2009=u200914.3) in the group with S. mutans expressing collagen binding activity, as compared to the group without that finding. Deep CMBs were more frequent (67%) and cognitive function was lower among subjects with cnm-positive S. mutans expressing collagen binding activity. This work supports the role of oral health in stroke and dementia and proposes a molecular mechanism for the interaction.

Endoscopic Removal of Neonatal Acute Epidural Hematoma via Strip-Bending Osteoplastic Craniotomy. Technical Note

We present a rare case of an acute epidural hematoma extending through a skull fracture into a cephalohematoma in a neonate. The epidural hematoma was caused by a fall after delivery. The neonate remained neurologically asymptomatic. A computed tomography scan 12 days after delivery showed the large-volume epidural hematoma with midline shift. We performed a strip-bending osteoplastic craniotomy and removed the epidural hematoma and external cephalohematoma under neuroendoscopic control. This is the first reported case of an acute epidural hematoma in a neonate treated successfully neuroendoscopically via a strip-bending craniotomy.

A Potential New Risk Factor for Stroke: Streptococcus Mutans With Collagen-Binding Protein

BACKGROUNDnAmong human oral bacteria, particular kinds of Streptococcus mutans (SM) known as dental caries pathogens contain a collagen-binding protein, Cnm, and show platelet aggregation inhibition and matrix metalloproteinase-9 activation. We have previously reported that these strains may be a risk factor for intracerebral hemorrhage. As a major sample-providing hospital, we report the clinical details, including intracranial aneurysms and ischemic stroke.nnnMETHODSnAfter the study received approval from the Ethical Committee, 429 samples of whole saliva were obtained from patients who were admitted to or visited our hospital between February 16, 2010, and February 28, 2011. The study cohort comprised 48 patients with cardioembolic stroke (CES), 151 with non-CES infarct, 54 with intracerebral hemorrhage (ICH), 43 with ruptured intracranial aneurysm (RIA), and 97 with unruptured intracranial aneurysm (UIA). Cultured SM was identified as Cnm-positive when the corresponding gene was positive. The results were compared with those from 79 healthy volunteers. Relationships between Cnm-positive SM and known risk factors, including hypertension, diabetes, hyperlipidemia, smoking, and alcohol consumption, were analyzed.nnnRESULTSnA statistically significant high Cnm-positive rate was observed in patients with CES, non-CES infarct, ICH, and RIA (Pxa0= 0.002, 0.039, 0.013, and 0.009, respectively). There were no relationships between Cnm-positive SM and known risk factors.nnnCONCLUSIONSnSpecific types of oral SM can be a risk factor for cardioembolic infarct, intracerebral hemorrhage, and intracranial aneurysm rupture. Further study is needed.

An Unusual Case of Lhermitte-Duclos Disease Manifesting with Intratumoral Hemorrhage

BACKGROUNDnLhermitte-Duclos disease (LDD) is a rare neurologic disease that causes a hamartomatous lesion in the cerebellum. LDD is usually associated with mass lesion effects, but with appropriate surgical treatment, the clinical course is usually benign. We report a rare case of a patient with LDD with contrast enhancement on magnetic resonance imaging (MRI) who died as a result of intratumoral hemorrhage.nnnCASE DESCRIPTIONnLDD was diagnosed in a 59-year-old woman after a routine MRI. She did not present with any symptoms initially or after follow-up MRI suggested minor hemorrhage in the tumor. Eleven months after her first visit to our department, she suddenly lost consciousness, and computed tomography revealed massive intratumoral hemorrhage. Surgical decompression was done, but she died 17 days after surgery. Histopathologic findings were consistent with LDD.nnnCONCLUSIONSnHemorrhagic events can occur with LDD, even though the growth of the lesion is slow. Long-term close follow-up of patients with LDD is needed, especially patients in whom MRI shows atypical enhancement. To avoid possible hemorrhagic events, surgical treatment should be considered even if only subtle changes are seen on neuroimaging.

Setting pressure can change the size and shape of MRI artifacts caused by adjustable shunt valves: a study of the 4 newest models

OBJECTIVEAdjustable shunt valves that have been developed for the management of hydrocephalus all rely on intrinsically magnetic components, and artifacts with these valves on MRI are thus inevitable. The authors have previously reported that the shapes of shunt artifacts differ under different valve pressures with the proGAV 2.0 valve. In the present study the authors compared the size and shape of artifacts at different pressure settings with 4 new-model shunt valves.METHODSThe authors attached 4 new models of MRI-resistant shunt valve to the temporal scalp of a healthy volunteer: the proGAV 2.0; Codman Certas Plus; Polaris; and Strata MR. They set 3 different scales of pressures for each valve, depending on magnet orientation to the body axis. Artifacts were evaluated and compared among all valves on a 3.0-T GE scanner and 2 valves were also evaluated on a Philips scanner and a Siemens scanner. In-plane artifact sizes were evaluated as the maximum distance of the artifact from the expected scalp.RESULTSThe sizes and shapes of artifacts changed depending on valve pressure for all valves on the 3 different MRI scanners. Artifacts were less prominent on spin echo sequences than on gradient echo sequences. For diffusion-weighted imaging and time-of-flight MR angiography, the authors matched image numbers within the same sequence and compared appearances of artifacts. For all valves, the number of images affected by artifacts and the image number showing the largest artifact differed among valve settings.CONCLUSIONSArtifacts of all adjustable shunt valves showed gross changes corresponding to pressure setting. Not only the maximum distance of artifacts but also the shape changed significantly. The authors suggest that changing pressure settings offers one of the easiest ways to minimize artifacts on MRI.