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Biomedical subjects

H Yamaga

Publications and source records attributed to H Yamaga.

At least 19 recordsLinked to original sources
PubMed2005

Endovascular treatment of unruptured cerebral aneurysms.

76 consecutive patients with 78 unruptured cerebral aneurysms underwent endovascular therapy from July 1999 to May 2004 in our institute. For the wide-necked aneurysms, the remodeling technique, double microcatheter technique, or stent-assisted coil embolization was used, while a parent artery occlusion or covered stent was applied for the giant or fusiform aneurysms. Immediate angiographical results demonstrated 33 complete occlusions, 26 neck remnants, and 14 dome fillings. Four cases were treated with parent occlusion or stenting only, and one case was not treated with embolization but with clipping due to the rupture of the aneurysm during coil embolization. Immediate angiographic findings demonstrated that in aneurysms between 5 to 10 mm, the rate of complete occlusion was 48%, that of neck remnants 33%, and that of dome fillings 27%. In aneurysms between 11 to 25 mm, the rate of complete occlusion was 14%, that of neck remnants 28%, and that of dome fillings was 58%. In the angiographic follow-up results, all aneurysms smaller than 5 mm showed complete occlusion. In aneurysms between 5 to 10 mm, 74% of the aneurysms showed complete occlusion, and 21% showed neck remnants, and 5% showed dome filling. In aneurysms between 10 to 24 mm, 25% showed complete occlusion, while 75% showed dome filling. The overall mortality rate was 0% and the morbidity rate was 3.7% (2 major strokes, 1 minor stroke) at 30-days after embolization. In the clinical follow-up study, one case of a large basilar tip aneurysm caused a fatal rupture 28 months after the initial embolization. Endovascular therapy was performed on the unruptured aneurysms and was found to be an acceptable treatment, except for durability in cases of large aneurysms.

Adult↗
PubMed2003

The mitochondrial acetoacetyl-CoA thiolase (T2) deficiency in Japanese patients: urinary organic acid and blood acylcarnitine profiles under stable conditions have subtle abnormalities in T2-deficient patients with some residual T2 activity.

Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inborn error of metabolism affecting isoleucine and ketone bodies in the catabolic process. Mutation analysis and expression analysis of mutant cDNAs have facilitated the division of T2-deficient patients into two groups: those with null mutations in either allele (group 1) and those with mutation(s) retaining some residual T2 activity in at least one of two mutant alleles (group II). Among 5 Japanese T2-deficient patients, GK01 belonged to group I and the other patients (GK19, GK19B, GK30 and GK31) to group II. As we have suggested previously, the severity of ketoacidotic episodes in the group II patients was similar to that in the group I patient. However, the urinary organic acid and blood spot acylcarnitine profiles under stable conditions differed between the two groups. The group I patient had typical profiles for the T2 deficiency. In contrast, in all four patients in group II, tiglylglycine was not or was only faintly detected and the 2-methyl-3-hydroxybutyrate levels were less than the cutoff value. Their tiglylcarnitine levels were within the normal range and 2-methyl-3-hydroxy-, butyrylcarnitine was detected just around the cutoff value in our newborn screening pilot test. Hence, these analyses under stable conditions are not reliable for diagnosing the T2 deficiency in the group II patients. The T2 deficiency (group II) can be misdiagnosed as normal if these analyses are performed under nonepisodic conditions and possibly during the newborn screening for inborn errors of metabolism.

Acetoacetates↗
PubMed2002

Transcortical mixed aphasia due to cerebral infarction in left inferior frontal lobe and temporo-parietal lobe.

We present a case of transcortical mixed aphasia caused by a cerebral embolism. A 77-year-old right-handed man was admitted to our hospital with speech disturbance and a right hemianopia. His spontaneous speech was remarkably reduced, and object naming, word fluency, comprehension, reading and writing were all severely disturbed. However, repetition of phonemes and sentences and reading aloud were fully preserved. Although magnetic resonance imaging (MRI) showed cerebral infarcts in the left frontal and parieto-occipital lobe which included the inferior frontal gyrus and angular gyrus, single photon emission CT revealed a wider area of low perfusion over the entire left hemisphere except for part of the left perisylvian language areas. The amytal (Wada) test, which was performed via the left internal carotid artery, revealed that the left hemisphere was dominant for language. Hence, it appears that transcortical mixed aphasia may be caused by the isolation of perisylvian speech areas, even if there is a lesion in the inferior frontal gyrus, due to disconnection from surrounding areas.

Aged↗
PubMed2002

Silent cerebral infarction and cognitive function in middle-aged neurologically healthy subjects.

We sought to clarify whether apparently silent cerebral infarcts and periventricular hyperintensities are associated with depressed cognitive function in middle-aged subjects. Subjects were 84 middle-aged neurologically normal adults who wished to undergo a screening examination of the brain. We performed magnetic resonance imaging (MRI) of the brain and neuropsychologic tests in all subjects. Silent cerebral infarcts and periventricular hyperintensities, respectively, were detected in 21 and 14 of 84 subjects. Mini-mental state (MMS) and Raven's colored progressive matrices (RCPM) scores were significantly lower in subjects with than without silent cerebral infarcts. By two-factor analysis of variance, MMS score was affected by silent cerebral infarcts or periventricular hyperintensities, with interactions between the two lesion types (P < 0.05). Silent cerebral infarcts may be an independent factor in the pathogenesis of intellectual dysfunction, but truly independent analysis is difficult because many subjects with silent cerebral infarcts also have periventricular hyperintensities.

Adult↗
PubMed2001

Memory impairment and spatial disorientation following a left retrosplenial lesion.

We treated a patient in whom a left retrosplenial lesion resulted in memory impairment and spatial disorientation. A 31 year old, right handed man was admitted to our hospital after the sudden onset of headache. He was alert, attentive and cooperative, and showed no motor or sensory deficits. Although intelligence was preserved, memory was obviously deficient. The patient proceeded in wrong directions after he left his hospital room and subsequently his home. Neuroimaging revealed a subcortical hematoma in the left cingulate isthmus, while single-photon emission computed tomography demonstrated decreased perfusion in the splenium and left parietal lobe.

Adult↗
PubMed2001

Transient crossed aphasia and persistent amnesia after right thalamic haemorrhage.

A 45-year-old right-handed woman suffered transient aphasia and persistent amnesia after a right thalamic haemorrhage. This patient appeared to have crossed aphasia, although it disappeared within 8 weeks. It is noteworthy that the patient had a unilateral right thalamic lesion but exhibited both verbal and non-verbal memory impairment. Computed tomography and magnetic resonance imaging revealed cerebral haemorrhage in the right thalamus involving the ventral anterior nucleus, medioventral nucleus, mamillothalamic tract, internal medullary lamina, and mediodorsal nucleus. An amytal test was performed and suggested that the right hemisphere was dominant for language functions and the left hemisphere was dominant for visuospatial functions. Single photon emission CT revealed a low perfusion area only in the right thalamus. These findings suggest that the right hemisphere might be dominant for both verbal and non-verbal memory function in this patient, although visuospatial function was lateralized in the left hemisphere.

Amnesia↗
PubMed2000

Treatment of restenosis after percutaneous transluminal angioplasty for internal carotid artery stenosis.

The efficacy of repeated percutaneous transluminal angioplasty (PTA) and carotid endarterectomy (CEA) was examined in patients with restenosis after PTA for carotid stenosis. After percutaneous transluminal angioplasty (PTA) for 63 cases of internal carotid stenoses 13 cases of restenosis appeared. They were treated by PTA or carotid endarterectomy. The treatment was chosen by the patient after explanation of each treatment. We initially treated seven patients by repeat PTA and six by carotid endarterectomy. The degree of stenosis improved from 82% to 30% on average after repeated PTA. However, one patient in the PTA group had restenosis, and carotid endarterectomy was then performed. The other cases also had restenosis and were treated by PTA. The six cases treated by carotid endarterectomy were successfully treated without difficulty. The success rate of PTA was 5/7 (71%) in the restenosis cases. Patients with a greater residual stenosis after initial PTA had significantly more frequent restenosis. Repeat PTA and CEA both appeared effective treatment for restenosis after initial PTA, although PTA had a restenosis rate similar to that of initial PTA.

Aged↗
PubMed2000

Haemorrhagic complication following percutaneous transluminal angioplasty for carotid stenosis.

We report 2 cases with haemorrhagic complications following percutaneous transluminal angioplasty (PTA) for carotid stenosis. Computed tomography (CT) scanning of these cases demonstrated diffuse subarachnoid haemorrhage in 1 case, and intracerebral haemorrhage in the other case on the next day after PTA. In the latter case, we measured cerebral blood flow velocity and mean transit time with transcranial doppler (TCD) and dynamic CT scan, which demonstrated remarkable increases in the blood flow velocity and peak height, respectively. From these results, postoperative hyperperfusion was suggested to have caused haemorrhagic complications.

Aged↗
PubMed1999

Transcortical sensory aphasia due to a left frontal subcortical haemorrhage.

A case of transcortical sensory aphasia caused by a cerebral haemorrhage in the left frontal lobe is presented. A 72-year-old right-handed woman was admitted to the hospital, with a history of acute onset of speech disturbance and headache. On initial assessment, her spontaneous speech was fluent. She had no difficulty initiating speech, articulated normally, and did not exhibit logorrhea. Her ability to repeat phonemes and short sentences (5-6 words) was fully preserved, however she had severe difficulty with visual recognition of words, and with aural comprehension at the word level, although she was able to read words aloud. Computed tomography and magnetic resonance imaging showed cerebral haemorrhage in the left frontal lobe, involving the superior and middle frontal gyrus. Single photon emission CT revealed a wider area of low perfusion over the entire left frontal lobe, including the superior, middle and inferior frontal gyrus. The aphasia symptoms, mainly poor comprehension, disappeared quickly several weeks after the event. This may have been due to a reduction in the size of the haematoma and a resolution of the oedema around the haematoma. Clinically, the transcortical sensory aphasia in this case was indistinguishable from that caused by damage to the posterior language areas. Further case reports of transcortical sensory aphasia associated with frontal lobe lesions would help to confirm whether a relatively rapid recovery is characteristic in cases such as this.

Aged↗
PubMed1999

[Construct validity of a new computer-assisted cognitive assessment battery in normal adults].

A computer-assisted battery for neuropsychological tests (CNT) has been designed to screen adults for cognitive impairment. The aim of this study was to gather evidence for the construct validity of CNT and also investigate the relationship between CNT and conventional neuropsychological tests. Subjects were 45 healthy adults (21 men and 24 women), who ranged in age from 20 to 70 years (mean = 33.5, SD = 1.9) with no history of substance abuse, or of psychotic or neurological disorders. The CNT in our study consists of six subtests designed to assess various components of driving, such as digit span, visual scanning, visual and verbal memory, complex reaction time, and vigilance. Mini-mental state test, Kana-hiroi test, word fluency, the auditory-verbal learning test and Raven's colored progressive matrices were also performed as conventional neuropsychological tests. Results showed there were high correlations between each CNT subtests and conventional neuropsychological tests. A factor analysis (with varimax rotation) identified 4 factors with eigen values greater than 1, which accounted for over 70% of the variance. CNT was able to estimate each factor related to cognitive function such as learning and memory, attention, judgment, and visual scanning selectively. CNT may thus be a useful tool for detection of cognitive impairment, although this test has important limitations. Broader applications of these tests will require extensive population-based validation.

Adult↗
PubMed1999

[Dural arteriovenous fistula at the cranio-cervical junction presenting transient ischemic attack: a case report].

A 58-year-old male was admitted to our hospital because of repeated transient ischemic attack of right hemiparesis and speech disturbance. A CT scan did not demonstrate any remarkable findings. No significant cerebral arterial stenosis or occlusion was found on angiography. However, dural arteriovenous fistula fed by the radiculo-meningeal artery was found at the cranio-cervical junction on left vertebral angiography. The shunt flow from the arteriovenous fistula drained into the superior petrosal sinus and sigmoid sinus in a retrograde fashion. On the angiographic findings when his transient ischemic attack (TIA) had disappeared, the venous drainage had returned to its normal fashion. Venous hypertension around the brain stem was supposed to have caused the transient ischemic attack in this case. We performed coagulation of the draining vein and fistula surgically. After surgery, the patient's TIA completely disappeared. We report the first case of dural arteriovenous fistula at the cranio-cervical junction presenting transient ischemic attack.

Aged↗
PubMed1998

[A case of agraphia due to cerebral infarction in the left parietal lobe].

A case of agraphia due to cerebral infarction in the left parietal lobe was reported. A 63-year-old right-handed man was admitted to our hospital with writing disturbance. His spontaneous speech was fluent, and object naming, word fluency, repetition, verbal comprehension, and reading were fully preserved. However, his writing was slow and required effort. He showed hesitation in spontaneous writing and dictation. His power to copy was better than his power to write spontaneously or to take dictation, but he had some difficulty in copying letters and complex figures. The patient showed abnormal sequences of strokes and completed his strokes by piecing out of several fragments. CT scan and MRI showed a cerebral infarction in the left parietal lobe which included the superior parietal lobule. The amytal (Wada) test, which was performed via the left internal carotid artery, revealed that the left hemisphere was dominant for language. The characteristics of his agraphia much more closely resembled "apractic agraphia", as reported by Alexander et al (1992), than spatial agraphia or pure agraphia. Agraphia in this patient might result partially from the loss or unavailability of the memory of motor patterns necessary for writing letters.

Agraphia↗
PubMed1997

A comparison of open and laparoscopic cholecystectomy for patients with cirrhosis.

To evaluate the benefits of performing laparoscopic cholecystectomy (LC) in patients with cirrhosis, data on 13 patients with liver cirrhosis who underwent cholecystectomy for gallstones between 1989 and 1995 were retrospectively collected from charts filed at Fukuoka City Hospital. These 13 patients were classified into two groups; one, comprised of 7 who underwent LC, and another, comprised of 6 who underwent open cholecystectomy (OC). No statistical differences were observed in the duration of surgery or the intraoperative blood loss between the two groups; however, the C-reactive protein (CRP) level in the serum was significantly higher in the OC group than in the LC group. LC was followed by a significantly earlier resumption of a normal diet (P < 0.05) and a shorter hospital stay (P < 0.05) in comparison to OC. All of the patients who underwent OC had an uneventful clinical course; however, one of the patients who underwent LC suffered from intractable ascites postoperatively. The difference in the cost of hospitalization between the two groups was not statistically significant. These findings suggest that the therapeutic significance of performing LC in patients with cirrhosis should be assessed after carefully evaluating all factors including mortality, morbidity, and cost-effectiveness. Thus, further controlled trials are necessary.

Aged↗
PubMed1997

Synthesis and biological properties of a new series of anti-MRSA beta-lactams; 2-(thiazol-2-ylthio)carbapenems.

A series of 1 beta-methylcarbapenems containing variously C-2 substituted thiazol-2-ylthio groups were synthesized, and their in vitro anti-MRSA activity was examined. Among them, 1 beta-methyl-2-(4-arylthiazol-2-ylthio)carbapenems exhibited superior anti-MRSA activity. Introduction of a cationic moiety in the C-2 side chain not only reduced the binding to HSA but also increased the stability against DHP-I, without affecting the anti-MRSA activity. It was also found that the distance between the cationic moiety and the carbapenem skeleton was related to the strength of HSA binding and the stability against DHP-I.

Anti-Bacterial Agents↗