Biomedical subjects

Masayuki Sasaki

Publications and source records attributed to Masayuki Sasaki.

At least 19 recordsLinked to original sources

PubMed2007

[A case of Möbius syndrome presenting with symptoms of severe infantile form of congenital muscular disorder].

Möbius syndrome is a rare disorder characterized by congenital bilateral facial nerve palsy. Abducent palsy or other cranial nerve palsy, facial malformations, limb malformations, and skeletal malformations are common features associated with this syndrome. We report a 9-month-old infant in whom congenital muscular disorder was previously suspected because of facial muscle involvement (mask-like face), respiratory and swallowing disturbances, and hypotonia since birth. After an improvement in the respiratory infection, she showed slightly exaggerated deep tendon reflexes and an improvement in muscle tone. The occurrence of combined facial nerve palsy, glossopharyngeal nerve palsy, vagus nerve palsy, and hypoglossal nerve palsy strongly suggested that she had Möbius syndrome. Finally, the absence of the roots of bilateral facial nerves on an MRI confirmed that the disorder was Möbius syndrome. We propose that a thin slice MRI should be obtained to observe the cranial nerves around the brain stem if patients show symptoms of congenital myopathy or congenital myotonic dystrophy as well as facial nerve and other cranial nerve paralyses.

Brain Stem↗

PubMed2006

Poly(ADP-ribose) (PAR) polymer is a death signal.

Excessive activation of the nuclear enzyme, poly(ADP-ribose) polymerase-1 (PARP-1) plays a prominent role in various of models of cellular injury. Here, we identify poly(ADP-ribose) (PAR) polymer, a product of PARP-1 activity, as a previously uncharacterized cell death signal. PAR polymer is directly toxic to neurons, and degradation of PAR polymer by poly(ADP-ribose) glycohydrolase (PARG) or phosphodiesterase 1 prevents PAR polymer-induced cell death. PARP-1-dependent, NMDA excitotoxicity of cortical neurons is reduced by neutralizing antibodies to PAR and by overexpression of PARG. Neuronal cultures with reduced levels of PARG are more sensitive to NMDA excitotoxicity than WT cultures. Transgenic mice overexpressing PARG have significantly reduced infarct volumes after focal ischemia. Conversely, mice with reduced levels of PARG have significantly increased infarct volumes after focal ischemia compared with WT littermate controls. These results reveal PAR polymer as a signaling molecule that induces cell death and suggests that interference with PAR polymer signaling may offer innovative therapeutic approaches for the treatment of cellular injury.

Animals↗

PubMed2006

Familial reducing body myopathy.

Reducing body myopathy (RBM) is a rare pathologically defined myopathy characterized by the presence of inclusion bodies which are abnormally stained by menadione-nitroblue-tetrazolium. The clinical symptoms vary widely as to the age of onset, disease progression and severity. Among the many reported patients, there have been only three families with this disorder, showing a manifold of clinicopathological features in each family. We report a fourth family with RBM affecting a boy and his mother. The proband (boy) began to have difficulty putting on his trousers at age 10years and difficulty arising from a chair at 11years. His spine was rigid. His mother, on the other hand, noticed foot-drop at the age 29, but the clinical course was rapidly progressive, and she was wheelchair-bound at 34years. Both patients had generalized muscle weakness and atrophy and with mild CK elevation. Muscle pathology was characterized by the presence of atrophic fibers with reducing bodies in some areas. As these patients demonstrate, clinical symptoms in RBM are very variable, even within the same family. There are no specific clinical characteristics distinctive to RBM, thus further studies are necessary to characterize this disorder both clinically and pathologically.

Adult↗

PubMed2006

Different SPECT findings before and after Capgras' syndrome in interictal psychosis.

We herein report a case of Capgras' syndrome observed in interictal psychosis in which the single-photon emission computed tomography (SPECT) findings before and after the appearance of the psychotic symptoms differed. SPECT with 99mTc-hexamethyl propyleneamine oxine (HMPAO) revealed worsening of hypoperfusion in the entire right hemisphere after onset of the psychotic symptoms. The enhanced hypoperfusion demonstrated by SPECT in the present case seems to indicate a right interhemispheric disconnection resulting in the occurrence of Capgras' syndrome.

Adult↗

PubMed2006

Basal ganglia lesions in a patient with 3-hydroxyisobutyric aciduria.

3-hydroxyisobutyric aciduria (3HiB-uria) is a very rare organic aciduria that involves valine metabolism. We report the case of a 7-year-old boy with 3HiB-uria who has suffered more than 20 ketoacidotic episodes since the age of 15 months. In the most recent ketoacidotic episode, which was particularly severe, he developed mild dystonia and choreoathetosis. Magnetic resonance imaging (MRI) revealed bilateral swelling and signal abnormalities of the putamina and heads of the caudate nuclei. The abnormal movements showed a gradual improvement over several months, in correlation with neuroradiological findings. 3HiB-uria should be recognized as one of the group of branched chain organic acidemias that can produce lesions in the basal ganglia.

Basal Ganglia↗

PubMed2006

Peripheral 5-HT2A receptor antagonism attenuates primary thermal hyperalgesia and secondary mechanical allodynia after thermal injury in rats.

Inflammation or injury of peripheral tissue causes release of chemical mediators, including 5-hydroxytryptamine (5-HT), which is involved in the facilitation of nociceptive transmission and the induction of hyperalgesia. The present study examined the effect of a selective 5-HT2A receptor antagonist, sarpogrelate, on hyperalgesia and allodynia induced by thermal injury in rats. Mild thermal injury to the hindpaw produces thermal hyperalgesia in the injured area (primary thermal hyperalgesia) and mechanical allodynia in sites adjacent to the primary area (secondary mechanical allodynia). Mechanical allodynia was assessed by paw withdrawal thresholds using von Frey filaments, and thermal hyperalgesia was assessed by paw withdrawal latencies upon exposure to a radiant heat source. Intraperitoneal administration (30-100 mg/kg) or local injection (30-300 microg) of sarpogrelate 10 min prior to thermal injury attenuated secondary mechanical allodynia in a dose-dependent manner. Intraperitoneal administration (3-100 mg/kg) or local injection (30-300 microg) of sarpogrelate 10 min prior to thermal injury attenuated primary thermal hyperalgesia in a dose-dependent manner. Intraplantar injection of sarpogrelate (300 microg) to the contralateral hindpaw had no effect on primary thermal hyperalgesia or secondary mechanical allodynia in the ipsilateral paw. The tissue concentration of 5-HT was measured using microdialysis. Concentrations of 5-HT increased after thermal injury in both primary and secondary areas, and the increase was not attenuated by pretreatment with sarpogrelate (100 mg/kg, i.p.). These data suggest that 5-HT released in peripheral tissues after thermal injury sensitizes primary afferent neurons and produces mechanical allodynia and thermal hyperalgesia via peripheral 5-HT2A receptors.

Animals↗

PubMed2006

Pre-surgical identification of epileptogenic areas in temporal lobe epilepsy by 123I-iomazenil SPECT: a comparison with IMP SPECT and FDG PET.

OBJECTIVES: The aim of this study was to evaluate the usefulness of (123)I-iomazenil (IMZ) single photon emission computed tomography (SPECT) for the pre-surgical identification of epileptogenic areas in patients with temporal lobe epilepsy and to compare the results with those of (123)I-IMP SPECT and (18)Fluorodeoxyglucose positron emission tomography (FDG PET). METHODS: We examined seven patients with medically refractory temporal lobe epilepsy (five men and two women; mean age, 28 years) with no remarkable findings on magnetic resonance imaging. Before surgery, IMZ SPECT, IMP SPECT and FDG PET were all performed in the interictal state. Then, visual assessment and region-of-interest (ROI) analysis were performed on each image. Final definitions of the epileptogenic areas were made by electrocorticography and histopathology. RESULTS: By IMZ SPECT, a decreased IMZ uptake in the ipsilateral temporal lobe was found in all patients, while a similar decrease in the contralateral temporal lobe was also found in one patient. In comparison to IMP SPECT, the extent of the abnormal area on IMZ SPECT was equal to that on IMP SPECT in one patient while it was more restricted to the epileptogenic area in five patients. In comparison to FDG PET, the extent of the abnormal area on IMZ SPECT was equal to that on FDG PET in three patients while it was more restricted in the epileptogenic area in four patients. In ROI analysis, decreases of IMZ, IMP and FDG uptake were observed in the epileptogenic area, although they were not statistically significant. CONCLUSIONS: IMZ SPECT was considered to be useful for pre-surgical determination of the epileptogenic areas in temporal lobe epilepsy with no remarkable MRI findings, and it was also found to be superior to IMP SPECT and FDG PET for this purpose.

Adolescent↗

PubMed2006

[Pleural effusion associated with long-term dantrolene administration in three patients with severe motor and intellectual disabilities].

Chronic unilateral pleural effusion developed in three patients with severe motor and intellectual disabilities. All patients received 5-15 years of dantrolene administration for their spasticity. The cause of pleural effusion was indistinct, despite close investigations for etiologies such as infection or tumor. The pleural fluid consisted of sterile exudate in all patients. One patient had eosinophilia in his pleural fluid, while peripheral blood eosinophilia was seen in the other two. The pleural biopsy and autopsy specimens revealed only non-specific inflammatory findings. After dantrolene therapy was discontinued, pleural effusion almost disappeared in two patients in the following several months, but the other died of multi-organ failure from another underlying disease. It is important to take chemical pleurisy into consideration when dealing with pleural effusion of unknown etiology. Moreover, respiratory side effect should be examined in patients treated with chronic dantrolene administration.

Adult↗

PubMed2006

[Case of 12-year-old boy with idiopathic recurrent neuralgic amyotrophy].

Here we report a 12-year-old boy with idiopathic neuralgic amyotrophy who had two episodes of shoulder pain followed by shoulder muscle atrophy and weakness at the age of 7 and 11 years, respectively. These symptoms were self-limited and disappeared within 9 months. During the second episode, electromyograph (EMG) revealed neurogenic changes in the deltoid muscle. Muscle imaging showed the right deltoid muscle atrophy with slightly high intensity areas on T1 and T2 weighted images in MRI. Muscle biopsy from the right deltoid muscle revealed neurogenic changes with denervating and reinnervating processes. Neuralgic amyotrophy is characterized by neuralgic pain followed by weakness and atrophy at a unilateral extremity and is usually self-limited. EMG and imaging studies showed focal neurogenic abnormalities, which were confirmed by muscle biopsy. Neuralgic amyotrophy usually occurs in young adults and it is very rare in children.

Brachial Plexus Neuritis↗

PubMed2006

[Two boys with non-progressive unilateral atrophy of the calf muscles].

We report here two boys who presented with atrophy of the right calf muscle. The onset was insidious and the symptom was found in infancy in case 2. They were followed for more than 5 years and no progression was seen. No sensory disturbances or autonomic nervous system symptoms were observed. Although needle electric myograph and muscle biopsy findings showed a neurogenic pattern, no cause was confirmed. Recently, a new disease concept of "benign monomelic amyotrophy of lower limb" was established and this could be applied to these patients. This disorder is rare and it is seen in young adults. It is characterized by non-progressive unilateral calf muscle atrophy. There is almost no possibility that this disorder is a variant of spinal muscular atrophy. When a patient presents with unilateral calf muscle atrophy, the treatable causes of the atrophy, including spinal cord disorders or peripheral nerve disorders, should be excluded first. If a confirmed cause cannot be found, then there should be a careful follow-up of the patient, even if the symptoms are stable.

Adolescent↗

PubMed2005

Fluctuating hearing loss, episodic headache, and stroke with platelet hyperaggregability: coexistence of auditory neuropathy and cochlear hearing loss.

We encountered a 10-year-old girl with fluctuating sensorineural hearing loss, episodic headache, and white matter stroke. Strenuous exercise, febrile illness, and general anesthesia all temporarily worsened hearing. Audiologic findings were asymmetric: left-sided retrocochlear dysfunction consistent with auditory neuropathy contrasted with cochlear hearing loss in the right ear. Platelets obtained during a headache-free period showed excessive responsiveness to collagen in vitro, while episodic elevations of thromboxane B(2) and thrombin-antithrombin III complex were noted in blood sampled during headache. Treatment of hyperaggregability of platelets with aspirin and antioxidant vitamins relieved headache, while adenosine triphosphate administration improved hearing thresholds. In this patient, hearing impairment and white matter strokes appeared to respectively related to impaired blood flow to the cochlea and white matter caused by platelet dysfunction triggered by physiologic stresses.

Adenosine Triphosphate↗

PubMed2005

Longitudinal MR findings in a patient with hemimegalencephaly associated with tuberous sclerosis.

A patient with an unusual association between tuberous sclerosis complex and hemimegalencephaly is reported. At 2 days of age, CT scan disclosed right hemimegalencephaly with periventricular faint calcification. At 1 month of age, magnetic resonance imaging showed right hemimegalencephaly with T1 and T2 shortening. The right frontal and parietal lobes were compatible with transmantle dysplasia. At 6 months of age, the right hemisphere had decreased in size. Atrophic changes continued to progress until 3 years of age. Periventricular calcification in the right hemisphere became marked with age. The patient developed frequent partial motor seizures from 6 weeks of age and infantile spasms from 5 months of age. Electroencephalogram revealed low amplitude of background activities in the right frontal area. The cause of this atrophic change in the hemimegalencephalic hemisphere, which could be a hamartomatous lesion, remains unknown.

Atrophy↗

PubMed2005

PET evaluation of the relationship between D2 receptor binding and glucose metabolism in patients with parkinsonism.

OBJECTIVE: To clarify the relationship between D2 receptor binding and the cerebral metabolic rate for glucose (CMRGlu) in patients with parkinsonism, we simultaneously measured both of these factors, and then compared the results. METHODS: The subjects consisted of 24 patients: 9 with Parkinson's disease (PD), 3 with Juvenile Parkinson's disease (JPD), 9 with multiple system atrophy (MSA), and 3 with progressive supranuclear palsy (PSP). The striatal D2 receptor binding was measured by the C-11 raclopride transient equilibrium method. CMRGlu was investigated by the F-18 fluorodeoxyglucose autoradiographic method. RESULTS: The D2 receptor binding in both the caudate nucleus and putamen showed a positive correlation with the CMRGlu in the PD-JPD group, but the two parameters demonstrated no correlation in the MSA-PSP group. The left/right (L/R) ratio of D2 receptor binding in the putamen showed a positive correlation with that of CMRGlu in the MSA-PSP group, while the two demonsrated no correlation in the PD-JPD group. CONCLUSION: Our PET study showed striatal D2 receptor binding and the CMRGlu to be closely related in patients with parkinsonism, even though the results obtained using the L/R ratios tended to differ substantially from those obtained using absolute values. The reason for this difference is not clear, but this finding may reflect the pathophysiology of these disease entities.

Adult↗

PubMed2005

Comparison of 18FDG-PET with 99mTc-HMDP scintigraphy for the detection of bone metastases in patients with breast cancer.

OBJECTIVE: Bone is one of the most common sites of metastasis in breast cancer patients. Although bone scintigraphy is widely used to detect metastatic breast cancer, the usefulness of 18FDG-PET for detecting bone metastasis has not been clearly evaluated. The purpose of this study was to compare the diagnostic accuracy of 18FDG-PET with bone scintigraphy in detecting bone metastasis in breast cancer patients. METHODS: Forty-four women aged 35 to 81 years (mean, 56 years) with breast cancer were examined in this study. Both 18FDG-PET and bone scintigraphy were performed for each patient with 0-69 day intervals (mean, 11.5 days). The results of each image interpretation were compared retrospectively. Whole-body bones were classified into 9 anatomical regions. Metastases were confirmed at 45/187 regions in 14 patients by bone biopsy or clinical follow-up including other imaging techniques for a period of at least 6 months afterwards. RESULTS: On a region basis, the sensitivity, specificity, and accuracy of 18FDG-PET were 84%, 99% and 95%, respectively. Although these results were comparable to those of bone scintigraphy, the combination of 18FDG-PET and bone scintigraphy improved the sensitivity (98%) and accuracy (97%) of detection. False negative lesions of bone scintigraphy were mostly bone marrow metastases and those of 18FDG-PET were mostly osteoblastic metastases. 18FDG-PET was superior to bone scintigraphy in the detection of osteolytic lesions (92% vs. 73%), but inferior in the detection of osteoblastic lesions (74% vs. 95%). CONCLUSIONS: This study shows that 18FDG-PET tends to be superior to bone scintigraphy in the detection of osteolytic lesions, but inferior in the detection of osteoblastic lesions. 18FDG-PET should play a complementary role in detecting bone metastasis with bone scintigraphy.

Adult↗

PubMed2005

Extraosseous accumulation of (99m)Tc-HMDP to radiation nephropathy, mimicking recurrent neuroblastoma.

OBJECTIVE: The aim of this study is to clarify the period of extraosseous accumulation of (99m)Tc-hydroxymethylenediphosphonate (HMDP) to radiation nephropathy mimicking recurrent or remnant neuroblastoma in the pararenal region. METHODS: We reviewed five neuroblastoma and one ganglioneuroblastoma patients (2 boys and 4 girls aged 1-9 years) who underwent (99m)Tc-HMDP bone scintigraphies periodically before and after radiation therapy. RESULTS: Increased renal uptake coincident with the radiation port appeared in 5 of 6 patients from 0 to 3 months (mean 1.7 months), and persisted up to 7 months after the completion of radiotherapy. Renal uptake of (99m)Tc-HMDP was gradually decreased, and eventually became accumulation defects in 5 of 6 patients from 6 to 17 months (mean 8.9 months) after radiotherapy. CONCLUSION: When extraosseous accumulation is found after radiation therapy in neuroblastoma patients, radiation nephropathy would be a candidate in the differential diagnosis besides recurrent or remnant tumor.

Bone Neoplasms↗

PubMed2005

Systemic ketamine inhibits hypersensitivity after surgery via descending inhibitory pathways in rats.

PURPOSE: Systemic ketamine suppresses several types of chronic pain. Although ketamine is used as a general anesthetic agent, the analgesic effect of systemic ketamine for early-stage postoperative pain is not clear. We investigated the efficacy and mechanism of systemic ketamine in a rat model of postoperative pain. METHODS: An incision was made in the plantar aspect of the left hind paw in male Wistar rats. Mechanical hypersensitivity was measured using calibrated von Frey filaments. The anti-hypersensitivity effect of systemic or intrathecal administration of ketamine was determined every hour after making the incision. We examined the effects of intrathecal pretreatment with yohimbine, an alpha2-adrenoceptor antagonist, and methysergide, a serotonergic receptor antagonist, on the anti-hypersensitivity effect of ketamine. We also examined the effect of systemic ketamine on the c-fos immunoreactivity in the spinal cord. RESULTS: Systemic administration of ketamine at doses from 3 to 30 mg.kg(-1) produced anti-hypersensitivity effects in a dose-dependent manner. Intrathecal administration of ketamine had no effect. There was no significant difference between effects of pre- and post-incisional administration. Intrathecal pretreatment with yohimbine (10 microg) or methysergide (15 microg) completely reversed the anti-hypersensitivity effects of systemic ketamine. Systemic ketamine reduced fos expression in laminae I-II in the dorsal horn of the lumbar spinal cord ipsilateral to the paw incision. CONCLUSIONS: The results suggest that systemic administration of ketamine perioperatively suppresses early-stage postoperative pain via monoaminergic descending inhibitory pathways.

Analgesics↗

PubMed2005

The involvement of nitric oxide in the enhanced expression of mu-opioid receptors during intestinal inflammation in mice.

Intestinal inflammation enhances the potency of mu-opioid receptor (MOR) agonists inhibiting gastrointestinal transit and increases the expression of MOR in mice intestine. The precise mechanisms implicated in the increased expression of MOR during intestinal inflammation are not known. The aim of the study is to evaluate if nitric oxide released during intestinal inflammation could modulate MOR gene expression and affect gastrointestinal transit. Intestinal inflammation was induced by the intragastric administration of croton oil. In CD-1 mice, with and without inflammation, we evaluated the anti-transit effects of morphine in animals treated with NOS inhibitors (L-NAME and L-NIL) and the intestinal levels of iNOS enzyme mRNA. The anti-transit effects of morphine and the expression of MOR mRNA in the gut of wild-type (WT) and iNOS-/- mice were also assessed. Gastrointestinal transit was measured with charcoal meal and mRNA levels determined by real-time PCR. In CD-1 mice, inflammation induced a 10-fold increase (P<0.0001) in iNOS mRNA levels in the gut. The absence of iNOS gene and treatment of CD-1 mice with L-NAME or L-NIL abolished the increased antitransit effects of morphine observed during inflammation. Moreover, although the basal levels of MOR mRNA were similar in WT and iNOS animals (-/-), intestinal inflammation only increased the MOR expression in the gut of WT (P<0.01) but not in iNOS-/- mice. The results suggest that nitric oxide derived from the increased expression of iNOS is implicated in the enhanced effects of morphine and in the upregulation of MOR gene transcription observed during intestinal inflammation.

Animals↗

PubMed2005

Clinical aspects of hemimegalencephaly by means of a nationwide survey.

We surveyed Japanese patients with hemimegalencephaly by means of a questionnaire. Clinical findings, including intellectual and motor function levels and epileptic symptoms, were investigated. All 44 patients (28 males and 16 females) with hemimegalencephaly were sporadic. Sixteen patients had underlying neurocutaneous syndromes. The number of patients with right-sided hemimegalencephaly (n = 29) was almost twice that of patients with left-sided hemimegalencephaly (n = 15). Forty-one patients had mental retardation and hemiparesis and 14 patients were bedridden. All patients had epileptic seizures, which first appeared within a month in 18 cases and within 6 months in 11 cases. In 42 patients, magnetic resonance imaging revealed both cortical and white-matter abnormalities in the affected hemisphere. Antiepileptic drugs were not very effective. Fifteen patients were surgically treated. Eleven patients underwent functional hemispherectomy, which resulted in fairly good seizure control and improved development. There is a correlation between the onset of epilepsy and the degree of clinical severity of motor deficit and intellectual level. Neither underlying disorders nor laterality of the affected side was related to the degree of clinical severity.

Adolescent↗