Role of Phage Shock Protein in Recovery of Heat-injured Salmonella.

　Sublethally heat-injured cells of Salmonella in food can recover under favorable conditions, leading to foodborne illness. To elucidate the molecular mechanism of recovery from heat injury, the global changes in gene transcription of Salmonella Typhimurium were investigated in previous study. In this study, the functions of genes involved in phage shock response (viz., phage shock protein (psp) genes), the transcription levels of which were found in previous study to be increased during recovery from heat injury, were investigated in recovering cells. The increase in pspABCDEFG transcription levels during the recovery process was confirmed by qRT-PCR. To understand the role of psp genes in heat injury recovery, a pspA deletion mutant (ΔpspA) and a pspA-overexpressing strain (S. Typhimurium pBAD30/pspA (+) ) were constructed. ΔpspA showed slightly lower viable counts and membrane potential than those of the wild-type strain during recovery. On the other hand, there was no significant difference in the viable counts between S. Typhimurium pBAD30/pspA (+) and the control strains S. Typhimurium pBAD30/pspA (-) and S. Typhimurium pBAD30 (+) during recovery. It would seem that a lack of PspA protein alone somewhat affects the recovery of S. Typhimurium from heat injury, but overexpression of PspA alone is not sufficient to overcome this effect.

Relationship between the Carotid Plaque T1 Relaxation Time and the Plaque-to-Muscle Signal Intensity Ratio on Black-Blood Magnetic Resonance Imaging Scans.

BACKGROUND: Black-blood magnetic resonance imaging (BB-MRI) is useful for the characterization and assessment of carotid artery plaques. The plaque-to-muscle signal intensity (SI) ratio (plaque/muscle ratio [PMR]) is used widely to evaluate plaques. However, the correlation between the PMR and the T1 relaxation time needs to be determined. We measured the T1 relaxation time of carotid plaques using T1 mapping and compared the results with the PMR on BB-MRI scans. METHODS: Between April 2014 and July 2015, 20 patients with carotid artery stenosis were treated by carotid artery stenting. All patients underwent preoperative magnetic resonance plaque imaging. The ratio of the plaque SI to the sternocleidomastoid muscle was calculated on T1-weighted BB-MRI scans. T1 mapping was performed in the region where the vessel was narrowest using the inversion recovery technique. The T1 relaxation time was recorded to determine whether there was a correlation with the PMR. RESULTS: The plaque T1 value was 577.3 ± 143.2 milliseconds; the PMR value obtained on BB-MRI scans was 1.23 ± .27. There was a statistically significant decrease in the T1 value as the PMR increased (P < .0001). CONCLUSIONS: As the T1 relaxation time was well correlated with the PMR on BB-MRI scans, the evaluation of vulnerable plaques using the PMR was reliable and convenient.

Changes in transcription during recovery from heat injury in Salmonella typhimurium and effects of BCAA on recovery.

Mechanisms of recovery from heat injury in Salmonella typhimurium were elucidated. Recovery of the heat-injured S. typhimurium cells in TSB resulted in full recovery after 3 h of incubation at 37°C. The DNA microarray analysis of 30- and 60-min recovering cells resulted in an increase in transcription of 89 and 141 genes, respectively. Among them, 15 genes, with known function, seemed to be somewhat involved in recovery. They encoded proteins involved in branched-chain amino acid (BCAA) transport (livJ, livH), cell envelope integrity (ddg), heat-shock response (cpxP, rrmJ), phage shock protein (pspA), ribosome modulation factor (rmf), virulence (sseB) transcriptional regulation (rpoE, rpoH, rseA, rseB, rseC) and ArcB signal transduction (sixA) and cytoplasmic membrane protein (fxsA). Among them, the effects of BCAA supplementation on recovery from heat injury were studied to confirm the importance of the BCAA transport liv genes during recovery. It was found that supplementation of TSB with 0.1% BCAA resulted in an enhanced recovery of injured cells in comparison to those recovered in TSB without BCAA. Supplementation of BCAA at 0.1% resulted in a cell count increase 4.4-fold greater than that of the control after 1 h incubation. It seems that BCAA promoted the recovery by promoting protein synthesis either directly through their use in translation or indirectly through stimulation of protein synthesis by activation of the Lrp protein.

Successful steroid pulse therapy for brain lesion caused by Shiga toxin 2 in rabbits.

Betamethasone sodium phosphate (BSP) is usually used as a steroid therapy for human brain edema. High doses of BSP (36mg/kg) twice a day for two days statistically reduced the mortality rate and improved the survival period of Stx2 (1.4mug/kg; 1.6LD(50))-toxemic rabbits. We made evaluations on three kinds of magnetic resonance images (MRI) including T1-weighted, T2-weighted, and enhanced MRI using gadopentetate dimeglumine (Gd-DTPA) to detect brain lesion induced by an intravenous injection of Stx2 in rabbits. Enhanced T1-weighted MRI was the most sensitive tool to find leakage of Gd-DTPA suggesting impairment of the blood brain barrier caused by Stx2. Enhanced MRI revealed that BSP treatment inhibited the leakage of Gd-DTPA, as directly evidenced by the protective effect of BSP against brain edema induced by intravenous injection of Stx2. Interleukin 1beta was not induced after Stx2 treatment in brain primary mixed cell culture.

[Case report of traumatic hemorrhage from the anterior choroidal artery].

Traumatic hemorrhage from the anterior choroidal artery is very rare. A 74-year-old male was admitted to our hospital immediately after a traffic accident. CT on admission showed right intracerebral hematomas in the posterior limb of the internal capsule and the upper part of the right cerebral peduncle. Neurological examination revealed that the patient had left hemiparesis and transient mute, pseudobulbar sign and peduncular hallucination. The absence of hypertensive asymptomatic microbleeds in other basal ganglia supported the verdict of traumatic injury of the anterior choroidal artery. The tear mechanism of the anterior choroidal artery might have been caused by an impact to the parietal region directed toward the tentorium.

[Isolated trigeminal sensory neuropathy due to pontine infarction of the root entry zone--report of two cases].

Secondary trigeminal neuralgia and isolated trigeminal neuropathy due to ischemic lesion of the pons are very rare. We report 2 patients with pontine infarct transecting the central trigeminal pathways resulting in trigeminal neuropathy and/or neuralgia. Case 1: A 48-year-old female presented with lancinating pain and paresthesia and hypesthesia in the right V2 and V3 distributions. Magnetic resonance imaging (MRI) of the brain demonstrated a wedge-shaped infarct at the root entry zone (REZ) of the right trigeminal nerve in the pons. Case 2: A 66-year-old female presented with paresthesia and hypesthesia in the right V1, V2 and V3 distributions. MRI demonstrated a small wedge-shaped infarct at REZ. This infarction of the REZ may have led to produce the isolated trigeminal neuralgia and trigeminal neuropathy.

[Rapid disappearance of acute epidural hematoma by percutaneous aspiration of subperiosteal hematoma--case report].

We present the case of an 8-year-old boy who was injured in a bicycle accident and was admitted with a right frontal skull fracture, an acute epidural hematoma, a right frontal laceration, and a subperiosteal hematoma on admission. After the frontal cutaneous suture, the subperiosteal hematoma was aspirated by the percutaneous needle. Two hours later, a CT scan revealed that the epidural hematoma was disappeared. It is speculated that the subperiosteal and epidural hematoma communicated via the skull fracture thus necessitating the evacuation of the epidural hematoma by subperiosteal aspiration.

[Conjugate deviation in ischemia of medial medullary oblongata--report of three cases].

Medial medullary infarct (MMI) is a rare type of brain stem infarction. Its clinical picture was characterized by contralateral hemiparesis, deep sensory disturbance, and ipsilateral hypoglossal paresis, but conjugate deviation or nystagmus is uncommon as initial symptom. Case 1: A 73-year-old man developed vomiting and vertigo. Examination revealed right conjugate deviation and horizontal nystagmus beating toward the left side, and numbness on his right upper limb,but no hypoglossal nerve palsy. Cranial MRI demonstrated an infarction in the left paramedian region of the upper medulla and thrombus of the left vertebral artery. Case 2: A 74-year-old man suffered from dizziness and nausea. He showed left conjugate deviation and right-beating horizontal nystagmus without Horner syndrome or hypoglossal nerve palsy. MRI disclosed an infarction in the right upper medial medulla. MRA revealed the right dissecting vertebral artery. Case 3: A 71-year-old man developed vertigo when watching at TV. He showed transient left conjugate deviation and transient motor paresis on the left upper limb. MRI showed the thickened wall of the right vertebral artery but no abnormal ischemic lesion. Digital subtraction angiograms revealed the dissecting right vertebral artery. All ischemic events limited to the upper third of the medulla were caused by the vertebral artery lesions, and prognosis was good. The unilateral MMI lesion in the nucleus prepositus hypoglossi and/or the medullary reticular formation caused contralesional shift of the eyes and ipsilesional nystagmus. The upper MMI will be characterized by a triad of contralateral hemiparesis, deep sensory disturbance and abnormal ocular motor findings.

Magnetic resonance for evaluation of toxic encephalopathies: implications from animal experiments.

Examinations of brain of rats intoxicated with hexachlorophene or acrylamide with ultrahigh-field (4.7 T) proton magnetic resonance (MR) showed alterations consistent with clinical pictures in humans and morphological findings in experimental animals. On the other hand, conventional biochemical analyses have revealed that ethylene oxide, methyl bromide, and acrylamide inhibit creatine kinase (CK; an enzyme catalyzing the reaction: ATP+creatine<-->ADP+phosphocreatine) activities in the brain of animals. Thus, 31P MR combined with magnetization transfer may be utilized to monitor living humans (or animals) intoxicated with these chemicals by determining CK activities in the target organ.

Neuronal damage in hydrocephalus and its restoration by shunt insertion in experimental hydrocephalus: a study involving the neurofilament-immunostaining method.

OBJECT: The morphological and functional impairments of neurons and their connections caused by hydrocephalus, and their restoration by ventricular shunt placement were investigated in experimental hydrocephalus by the immunostaining of neurofilaments, which constitute the major component of the neuronal cytoskeleton. METHODS: Progressive hydrocephalus was induced in 15 young mongrel dogs 1 to 2 months of age, 3 to 4 weeks after cisternal injection of kaolin. The dogs were divided into three groups of five animals each, a "preshunt," "post-shunt," and "nonshunt" group, depending on whether the hydrocephalic animals underwent a procedure to insert a ventriculoperitoneal shunt. Neurofilament, glial fibrillary acid protein (GFAP), and synaptophysin immunostaining were performed using samples of brain tissue from each hydrocephalic group and a fourth "control" group (five animals). In the cortex, morphological deformation and heterogeneous neurofilament immunoreactivity of the apical dendrites became pronounced in accordance with the progression of hydrocephalus (from the preshunt to the nonshunt group), and these changes remained after shunt insertion (postshunt group). In the periventricular white matter, swollen and fragmented axons increased in number along with hydrocephalic progression and were incompletely repaired by ventricular shunt placement. The GFAP-positive astrocytes observed around repaired axons in the postshunt group were seen more prominently than in the untreated hydrocephalic groups. In the internal capsule, fairly good recovery from axonal damage caused by the hydrocephalic condition was achieved by insertion of a ventricular shunt, compared with that seen in the periventricular white matter. CONCLUSIONS: Cytoskeletal damage of neurons in hydrocephalus and its incomplete restoration by shunt placement were most significant in the periventricular white matter. This finding may account for the impaired cognitive function seen in children who have shunts and an apparently reconstituted cerebral mantle; therefore, neuronal protection in the early hydrocephalic state should be considered.

[Evaluation of the vocal tract during Japanese vowel production in myasthenia gravis using magnetic resonance imaging].

We report a 65-year-old Japanese female whose primary symptom of myasthenia gravis was related to rhinolalia aperta. The vocal tract during vowel production was evaluated using two-dimensional fast advanced spin echo (2D-FASE) MR images on supine and prone position. Before treatment, MRI on prone position demonstrated anterior shift of the palatine uvula and the tongue during Japanese "a", "u" and "o" production following the gravity, the former suggested the paresis of the sphenosalpingostaphylinus and elevator veli palatini muscle and the latter the paresis of the styloglossal and hypoglossal muscles. After treatment of steroid pulse and immune absorption, 2D-FASE images on prone position revealed the normalized configuration of the tongue and the soft palate during the Japanese five-vowel production. Kinetic MRI may be useful for evaluation of dynamics of the tongue and the soft palate.

[Delayed epidural bleeding caused by traumatic pseudoaneurysm of the middle meningeal artery: case report].

A 16-year-old man who presented with delayed bleeding of epidural hematoma is reported. Computed tomography (CT) on admission demonstrated a small amount of right epidural hematoma and a small fracture of the right lateral orbital wall. He was treated conservatively. Repeated CT scans and magnetic resonance (MR) imaging revealed no growth in the epidural hematoma, but demonstrated flow void sign at the medial side of the hematoma on MR images. After 8 days, CT scan presented the regrowth of the hematoma, so we planned the removal of hematoma. Epidural hematoma due to the rupture of a traumatic pseudoaneurysm of the middle meningeal artery is rare. Especially, since traumatic lesions were diagnosed by CT, it was unusual to be able to diagnose the pseudoaneurysm of middle meningeal artery preoperatively. The cases of epidural hematoma treated conservatively should be followed up by MR imaging and MR angiography using the fat suppression technique.

[Case report of Rosai-Dorfman disease mimicking pachymeningitis].

Rosai-Dorfman disease (RDD) is a rare idiopathic histioproliferative disease affecting the lymph nodes. Extranodal sites may be involved and occasionally represent the initial or sole manifestation of the disease. Central nervous system manifestations especially are exceedingly rare. We reported a case of isolated, intracranial, dural-based RDD. A 69-year-old male, admitted with a second generalized convulsion, was examined by high-resolution MR images that revealed a thickened, stratified dura in the left frontal region with associated cortical edema. The patient underwent craniotomy with subtotal resection of the lesion. Microscopically, with the cytoplasmic staining against S-100 protein the lesion was shown to consist of proliferative histiocytes exhibiting emperipolesis. The histopathological diagnosis was compatible with RDD. The diagnosis of RDD mimicking pachymeningitis is presented, and the previous reported cases of intracranial RDD are reviewed.

Preoperative evaluation of trigeminal neuralgia due to epidermoid tumor using a three dimensional fast advanced spin echo--case report.

We report preoperative virtual images reconstructed from three-dimensional fast advanced spin echo (3D-FASE)and evaluate the cause of a trigeminal neuralgia due to an epidermoid tumor. A 60-year-old man had a 3-year-history of atypical trigeminal neuralgia in the left V2 region accompanied by a hypesthesia in the cheek. Neuroimaging demonstrated an epidermoid tumor in the left cerebello-pontine cistern. As the preoperative virtual images reconstructed from 3D-FASE images indicated that the superior cerebellar artery compressed the trigeminal nerve at the root entry zone, we carried out total removal of the tumor and microvascular decompression of the trigeminal nerve. It was possible to visualize the fine structures around the trigeminal nerve, because an epidermoid tumor shows a high intensity mass on 3D-FASE images. The simulated 3D images were useful in deciding upon the additional microvascular decompression surgery for trigeminal neuralgia after total removal of the epidermoid tumor.

[Rapid improvement of callosal edema by thiamine administration in Marchiafava-Bignami disease: a case report].

Marchiafava-Bignami disease (MBD) associated with chronic alcoholism is a fatal disorder characterized by demyelination of the corpus callosum. A 62-year-old Japanese man, a heavy drinker for his last over 10 years, was admitted to our hospital because of acute onset of speech disturbance. The first MR images showed abnormal signal intensity of the corpus callosum, which was a typical finding of MBD, but no signal abnormality on diffusion-weighted images. At three days after large doses of thiamine administration, MR studies revealed the disappearance of callosal high signal intensity. His symptom gradually improved, the pathogenesis and therapy of MBD were discussed.