Biomedical subjects
Publications and source records attributed to F Yoshii.
We report a patient with herpes simplex virus type 1 encephalitis (HSE) who showed abnormal magnetic resonance imaging (MRI) signals in the basal ganglia. The lesions were asymmetric and became apparent with relapse of the neurological symptoms, but they completely disappeared, concomitantly with improvement of the illness.
We report a case of 30-year-old man with generalized seizure, who had received phenytoin (PHT) for more than 6 years, but developed decrease in sperm count and motility. After PHT had been discontinued and valproate (VPA) had been administered for 3 months, his sperm activity became normalized. The decrease in sperm motility was the most important cause of his infertility. Sperm motility has been reported to be inversely correlated with the ratio of the concentrations of antiepileptic drugs in the plasma and semen. In our case, the ratio was 0.21 for PHT and 0.08 for VPA. We wish to emphasize the importance of measuring the concentration of antiepileptic drugs in the semen of infertile young males if they are on anticonvulsants.
We report a patient with medial medullary infarction who showed deep sensory impairment as his prominent neurological manifestation. A 54-year-old man with a history of hypertension was admitted to our hospital with numbness of the bilateral upper and lower extremities, followed by dysarthria and right hemiparesis. Physical examination revealed no abnormalities except for high blood pressure. He hiccuped continuously. On neurological examination, he exhibited dysarthria, mild dysphagia and right hemiparesis without facial or lingual paresis. Sensitivity to light touch and pinprick was normal, but sensitivity to vibration and joint position was severely decreased in the bilateral upper and lower extremities, predominantly in the lower extremities and on the right side in the upper extremities. He had been treated with antiedema agents and thromboxane synthetase inhibitor. His hiccups stopped within two weeks, and his right hemiparesis gradually improved within one month. However, his deep sensory impairments remained prominent. Blood examinations disclosed positive lupus anticoagulant. MRI showed bilateral infarction at the medial portion of the upper medulla oblongata, extending to both pyramids, especially on the left. Somatosensory evoked potentials (SEP) after median nerve stimulation showed P14 and the later components with prolonged latency. No SEP were recorded after posterior tibial nerve stimulation. The latency of P14 was well correlated with the severity of deep sensory impairments in the upper extremities. Neurological manifestations of our patient are not typical of medial medullary infarction, and are informative about the functional anatomy of the deep sensory tract in the medulla oblongata. We discuss the relation of the intractable hiccups to the bilateral medial medullary lesions, and emphasize the importance of lupus anticoagulant as one of the risk factors in brainstem infarction.
Explore the source record for details and available documents.
Quantitative relationship between chemical structure and oral bioavailability of 188 non-congeneric organic medicinals were studied to construct an expert system for predicting pharmacokinetic properties of organic chemicals. The compounds studied were classified into three groups: non-aromatics, aromatics, and heteroaromatics. Their oral bioavailability data observed in human adults were allotted into three ratings, and the relationships with chemical structure were analyzed using fuzzy adaptive least-squares. Quantitative relationship models formulated for the three structure groups gave significant information about factors influencing bioavailability, and were statistically reliable in both recognition and leave-one-out prediction despite the diversity and complexity of the structures of the compounds investigated.
The correlation of chemical structures with the volume of distribution of 373 miscellaneous medicinals was studied to construct an expert system for predicting the pharmacokinetic properties of organic chemicals. The compounds studied were classified into three groups; non-aromatics, aromatics, and heteroaromatics. Their total body volumes of distribution observed in human adults were allotted into three ratings, and the relationships with chemical structure were analyzed using the fuzzy adaptive least-squares method recently developed in our laboratory. Quantitative relationship models formulated for the three structure groups gave significant information about factors influencing the volume of distribution, and were statistically reliable both in recognition and leave-one-out prediction despite the diversity and complexity of the structures of the compounds investigated.
Twenty subjects with mildly to moderately severe Alzheimer disease (AD) and 14 normal elderly control subjects were studied using [18F]fluorodeoxyglucose and positron emission tomography (PET) to investigate regional cerebral glucose metabolism during both a resting state and a behavioral activation state, utilizing a reading memory task (RMT). The RMT produced significant global metabolic activation of 15 +/- 15% in normal subjects and 11 +/- 13% in AD subjects. The occipital regions were preferentially activated, but all regions in both groups were also significantly activated. The RMT did not allow a better discrimination of AD patients from normal controls on the basis of regional metabolic deficits. Regions in the AD group that were individually classified as hypometabolic during rest also exhibited metabolic activation. The apparent viability of hypometabolic regions in AD patients challenges current hypotheses regarding the cause of abnormal metabolism in AD.
A 43-year-old woman had noticed muscular weakness in her arms for four years before her admission. Muscle weakness and atrophy were prominent in the bilateral deltoid muscles, but muscular strength was almost unimpaired in the bilateral forearms and intrinsic muscles. There was no sign of sensory impairment except vibratory sensation. EMG revealed neuropathic NMU. X-P of the cervical spine showed enlargement of the spinal canal diameter, and MRI of the spinal cord revealed a large syrinx. On the basis of metrizamide CT and cranial MRI, a diagnosis of syringomyelia with Chiari malformation (type I) was made. Despite the presence of a large syrinx extending from C 1 to Th 11, the only detectable neurological sign was proximal weakness of the upper extremities simulating myopathy.
The effect of behavioral activation on cerebral and cerebellar glucose metabolism was studied in normal subjects when performing either a verbal memory task or a tactile somatosensory task. Each subject was also studied in a resting state control condition, either 1 h earlier or later than the activation task. Compared to the resting state, both tasks produced asymmetrical metabolic activation, which was opposite in direction within the cerebral and cerebellar hemispheres. In both tasks, the difference of activation of CMRglc in the right and left hemispheres in the cerebellum was negatively correlated with that in the sensory-motor region. This apparently coupled metabolic activation of one cerebellum and areas within the opposite cerebral hemisphere represents the inverse of the crossed cerebellar diaschisis phenomenon commonly observed when a vascular lesion affects one cerebral hemisphere and hypometabolism occurs in the opposite cerebellum. Because these correlations were selective and concordant with known anatomical connections, and were found in two different tasks, they suggest strong functional connections between these specific brain regions.
Positron-emission tomography (PET) was used to study regional cerebral metabolic activity during oral reading in right-handed adult males with, and without a childhood and family history of developmental dyslexia. Significant group differences in normalized regional metabolic values were revealed in prefrontal cortex and in the lingual (inferior) region of the occipital lobe. Lingual values were bilaterally higher for dyslexic than normal readers. In contrast to the asymmetry observed in prefrontal and lingual regions in nondyslexic subjects during reading, the dyslexic pattern was more symmetric. These results demonstrate that individuals who suffered from familial developmental dyslexia as children, activate different brain regions during reading as adults, as compared to individuals without such childhood history.
A 63-year-old man with clinical features of typical ataxic hemiparesis is reported. CT scan and magnetic resonance imaging showed a small infarction in the contralateral semioval center near the parietal cortex. Of note is the previously unreported site of the lesion relative to this syndrome. The neuroanatomical basis for the ataxic hemiparesis syndrome is discussed.
Neuroradiological findings of a patient with paretic neurosyphilis are described. A 50-year-old male patient showed personality changes, severe dementia and some neurological deficits. Serological analysis of serum and cerebrospinal fluid demonstrated the presence of antibodies to Treponema pallidum. Computed tomography showed diffuse cerebral cortical atrophy and ventricular dilatation, and magnetic resonance (MR) imaging revealed some small abnormal signals in the white matter. Single photon emission tomography using [123I] N-isopropyl-p-iodoamphetamine (IMP-SPECT) indicated decreased activities, most markedly in the right frontal and bitemporal cortices. Although the neuroradiological findings were nonspecific, the MR imaging and IMP-SPECT findings were interesting because they have not been described previously to our knowledge.
Fifteen male homosexual subjects (mean age 31.6 +/- 7.2 yr) who were asymptomatic, but HIV-1 seropositive (HIV+) were compared to 15 male age-matched HIV-1 seronegative (HIV-) subjects using resting PET/FDG studies and MR scans. Mean cerebral metabolic rates for glucose (mg/100 g/min) in the HIV+ and HIV- subjects were 7.7 +/- 1.7 and 7.0 +/- 2.1, (p = 0.44), respectively. An index of regional metabolic asymmetry for the whole brain was 5.8% +/- 3.2% in the HIV+ and 2.7% +/- 2.3% in the HIV- (p = 0.002), and the difference was most prominent in the prefrontal area. Significant asymmetries were found in 10/15 HIV+ subjects, primarily in prefrontal (7/15) and premotor (4/15) regions. MRI scans showed no abnormalities on clinical or quantitative evaluation in HIV+ subjects. Upon follow-up of HIV+ subjects over 18-40 mo, seven became symptomatic, of which two died. There was no relationship between the presence of PET scan abnormalities and earlier onset of symptomatic disease.
The widths of the anterior white matter bundle (AWM) and the interhemispheric (AWM-TER) and intrahemispheric (AWM-TRA) bundles at the level of the foramen of Monro on horizontal inversion recovery MRI scans were measured in 17 patients with dementia of Alzheimer type (DAT), 16 patients with multi-infarct dementia (MID) and 47 age-matched normal subjects (NOR). The area of the corpus callosum (CC) on midsagittal spin-echo MRI scans was also measured in 12 DAT, 11 MID and 36 NOR. The Mini-mental score in patients with DAT was 20.8 +/- 5.9, which was not significantly different from that of 22.9 +/- 5.4 in patients with MID. The width of AWM was not significantly decreased in either DAT or MID compared with NOR. However, the width of AWM-TER in DAT and MID showed a significant decrease from that in NOR. The width of AWM-TRA was decreased significantly only in DAT. Compared with NOR, the area of the CC in DAT and MID was decreased by 7.0% (p less than 0.05) and 6.5%, respectively. The white matter bundle has an important role in the connectivity of the brain. Although loss of white matter occurs in both DAT and MID, the change appears more diffuse in DAT than MID.
Metabolic activation of the right and left somatosensory cortices (SSC) in response to an active sensorimotor task (palpation and sorting of mah jongg tiles) was studied in 16 right-handed normal volunteers using positron emission tomography (PET) and a double-injection [18F]fluorodeoxyglucose strategy. In 8 subjects with right-hand stimulation, cerebral metabolic rate for glucose (CMRglc) in the contralateral SSC increased by 16.7 +/- 5.1% (mean +/- S.D.); the increase in the ipsilateral SSC was 4.8 +/- 3.2%. In contrast, in the 8 subjects with left-hand stimulation, the contralateral increase was 12.0 +/- 2.9% and the ipsilateral increase was 5.9 +/- 1.5%. Thus, contralateral SSC activation was significantly higher with stimulation of the right hand, while the ipsilateral/contralateral symmetry of activation was greater when the left hand was stimulated.
Thirty-one patients with probable Alzheimer's disease and 11 patients with memory disorders, attributable to multiple cerebral infarctions, were studied using 18-F-fluorodeoxyglucose-positron emission tomography scans. Asymmetry in cerebral glucose metabolism within these diagnostic groups was assessed by comparison with the metabolic rates obtained in age-equivalent healthy control subjects. A significantly greater number of individuals in both patient groups exhibited predominant left rather than right hemisphere hypometabolism. In addition, for patients with Alzheimer's disease, the degree of asymmetry was not related to either the severity or duration of dementia. These findings could be explained by greater susceptibility of the left hemisphere to degenerative or ischemic brain disease, by a specific sampling effect, or most likely, by greater metabolic deficits resulting from left rather than right hemisphere impairment.
The width of the anterior whole white matter bundle (AWM), interhemispheric (AWM-TER), and intrahemispheric (AWM-TRA) components at the level of the foramen of Monro on horizontal inversion recovery (IR) magnetic resonance (MR) scans were measured in 32 healthy males. The mean age of subjects were 54.4 +/- 18.8, ranged 25 to 83 years old. MR scans were performed using a 0.5 Tesla superconductive magnet, with inversion time of 400 msec, repetition time of 2.1 sec and echo time of 35 msec. The slice thickness was 10mm. Horizontal maximum internal skull diameter (HISD) at the same level was also measured and normalized values of AWM, AWM-TER, AWM-TRA were calculated by dividing the width of AWM, AWM-TER, AWM-TRA by the width of HISD. When absolute values of each AWM width were compared between right and left sides, there were no differences in AWM and AWM-TER. However, AWM-TRA of the right side was significantly wider than that of the left side (t = 4.28, p less than 0.001). The width of AWM was not correlated with age, but the width of AWM-TER showed a significant decline in the left (r = -0.36, p = 0.04) and non-significant trend to decline in the right side (r = -0.33, p = 0.07). The width of AWM-TRA of the left side was tended to decrease with age. Normalized values of AWM, AWM-TER, AWM-TRA showed a similar results as that of the absolute values. The measurement of the white matter bundle width provide some insights into the connectivity of the brain.(ABSTRACT TRUNCATED AT 250 WORDS)
The area of the corpus callosum (CC) on midsagittal spin-echo sequence magnetic resonance (MR) scans was measured in 64 normal subjects and 12 patients with Alzheimer's disease (AD). The normal subjects consisted of 32 males and 32 females, aged 25 to 83 years old. There was no significant age difference between males and females. Fifty-five out of 64 subjects were right-handed (RH) and 9 were left-handed or ambidextrous (NRH). Among patients with AD, 5 were males and 7 were females, aged 53 to 79 years old. Diagnosis of AD was performed mainly based on clinical history, magnetic resonance image (MRI) and positron emission tomographic findings. The outline of the CC on midsagittal MR film was traced and the total callosal sectional area (CCT) as well as the anterior half (CCA), posterior half (CCP) and posterior 5th or splenium (CCS) area measurements were performed using a planimeter. In either normal males or females, the CCA showed a significant negative correlation with age, but the CCP and the CCS did not correlate with age. Total CC (CCT) area was 691.2 +/- 91.0 sq. mm for the whole group and no difference was found between males and females. When the CC area was normalized with respect to the midsagittal area of the supratentorial portion of the brain (MSB), females were found to have a larger CC than males. No portion of the CC area was significantly different between RH and NRH subjects in absolute or normalized measures.(ABSTRACT TRUNCATED AT 250 WORDS)