Biomedical subjects

N Handa

Publications and source records attributed to N Handa.

At least 55 records · Page 3Linked to original sources

PubMed1997

[The clinical efficacy of imipenem/cilastatin sodium in orthopedic infections and drug levels in the bone tissue].

We evaluated the clinical efficacy of imipenem/cilastatin sodium (IPM/CS--a carbapenem antibiotic) against orthopedic infections, and the drug levels of the bone tissues were determined. The clinical efficacies for 6 patients in the infection group were good in 3 cases, and fair in the other 3; giving an efficacy rate of 50%. Bacteriologically, 8 strains were isolated from patients with the infection and an eradication rate of 87.5% was obtained upon the treatment. In 39 patients that were given the drug prophylactically, no postoperative infections occurred. Mean IPM levels in the bone and the bone marrow at 1 hour after administration in 5 patients of the prophylactic group were 17.3 micrograms/ml and 5.9 micrograms/g, respectively. The ratio of concentrations the bone to those in the bone marrow was 34.6%. The results of this study suggest that IMP/CS reaches to the bone tissue providing sufficient concentrations and that the drug is efficacious for the prophylaxis and the treatment of orthopedic infections.

Adolescent↗

PubMed1996

Effect of transcranial Doppler intensity on successful recording in Japanese patients.

The major limitation of transcranial Doppler sonography (TCD) is the failure to obtain data for all patients. The purpose of this study was to determine in detail the effect of increasing ultrasonic acoustic intensity on the rate of successful recording of intracranial blood velocity signals. The study was performed in 239 Japanese patients using a 2-MHz range-gated, pulsed-wave TCD. The middle cerebral artery flow signals were recorded at 76, 152, 228, 304, 380, 456 and 532 mW/cm2 and the results analyzed by age, gender and intensity. The rate of successful recording showed significant increase with the ultrasonic intensity in both genders (45.7% at 76 mW/cm2 vs. 81.1% at 532 mW/cm2 in males and 29.5% vs. 60.7% in females). However, recording was only successful in 54% of aged (50-89 gamma) female patients at the highest ultrasonic intensity used. It should be possible to significantly increase TCD usefulness in an aging Japanese population by further increasing TCD acoustic intensity within safety limitation.

Adult↗

PubMed1996

[Non-specific neurological complaints and silent cerebral infarction].

To clarify the relationship between non-specific neurological complaints and silent cerebral infarction (SCI), we studied 82 patients (56 +/- 8 years old; mean +/- SD) who presented with at least one complaint (headache, dizziness, forgetfulness) and 76 normal volunteers with no complaints (55 +/- 7 years old). All subjects were evaluated with a questionnaire for complaints and with 0.5 T magnetic resonance imaging of the brain for the presence of SCI. Several risk factors for stroke were also studied. SCI was significantly more common in the patients (18%) than in the normal subjects (7%, p < 0.05). SCI was more common in subjects with dizziness (40%) and in those with headache (18%) than in those with no complaints (p < 0.01, p < 0.05, respectively). Dizziness and forgetfulness were closely associated with SCI (p < 0.05). Two risk factors for stroke, age and hypertension, correlated with SCI. These results clearly show that non-specific neurological complaints are closely related to SCI.

Aged↗

PubMed1996

[A case of predominant right thalamic infarction with severe verbal memory disturbance].

We encountered a 45-year-old right-handed man who had suffered a predominant right thalamic infarction and complained of memory loss. Performance on the Miyake Test (recall of ten pairs of related and unrelated words), the Rey Osterrieth Complex Figures, the Benton Test of Visual Retention and the Wechsler Memory Scale-R disclosed a severe verbal memory disturbance associated with a little, if any, visual memory disturbance. An MRI study revealed bilateral lesions limited to the thalamus involving most of the right anterior nucleus (AN), mediodorsal nucleus (MD), ventrolateral nucleus (VL), and centromedial nucleus (CM), as well as a small part of the left MD, and CM. HM-PAO-SPECT scans showed areas of decreased cerebral blood flow not only in the right thalamus but in the medial and basilar region of the right temporal lobe. It is noteworthy that our patient had a predominant right thalamic lesion and exhibited a severe verbal memory disturbance rather than visual memory disturbance. This suggests that the right hemisphere is dominant for verbal memory function in this patient.

Cerebral Infarction↗

PubMed1995

Restriction-modification systems as genomic parasites in competition for specific sequences.

Restriction-modification (RM) systems are believed to have evolved to protect cells from foreign DNA. However, this hypothesis may not be sufficient to explain the diversity and specificity in sequence recognition, as well as other properties, of these systems. We report that the EcoRI restriction endonuclease-modification methylase (rm) gene pair stabilizes plasmids that carry it and that this stabilization is blocked by an RM of the same sequence specificity (EcoRI or its isoschizomer, Rsr I) but not by an RM of a different specificity (PaeR7I) on another plasmid. The PaeR7I rm likewise stabilizes plasmids, unless an rm gene pair with identical sequence specificity is present. Our analysis supports the following model for stabilization and incompatibility: the descendants of cells that have lost an rm gene pair expose the recognition sites in their chromosomes to lethal attack by any remaining restriction enzymes unless modification by another RM system of the same specificity protects these sites. Competition for specific sequences among these selfish genes may have generated the great diversity and specificity in sequence recognition among RM systems. Such altruistic suicide strategies, similar to those found in virus-infected cells, may have allowed selfish RM systems to spread by effectively competing with other selfish genes.

Binding, Competitive↗

PubMed1995

Yolk sac tumor in a case of testicular feminization syndrome.

A 17 month old who had been diagnosed as having testicular feminization syndrome (noted during inguinal herniorrhaphy) was operated on because of an abdominal mass that had a high serum level of alpha-fetoprotein. Histologically, the lesion was a yolk sac tumor. The alpha-fetoprotein level normalized within 2 months of the surgery, through the administration of adjunctive chemotherapy containing cisplatinum. The patient is disease-free 4 years postoperatively. When performing inguinal herniorrhaphy in a girl, the surgeon should be prepared to deal with testicular feminization syndrome. If gonadal neoplasm is deniable at the time of diagnosis, careful follow-up examinations are needed until completion of the development of secondary sex characteristics.

Androgen-Insensitivity Syndrome↗

PubMed1995

Candidemia in non-neutropenic patients with an intravenous hyperalimentation catheter: good prognosis of Candida parapsilosis infection.

Positive blood cultures reported between 1986 and 1993 at the Tokyo Metropolitan Komagome Hospital were evaluated and all patients with an intravenous hyperalimentation catheter who developed candidemia, a total of 94 patients, were analyzed further, while patients with neutropenia were excluded. The primary diagnosis was malignancy in 87.2% of the cases, and Candida albicans and C. parapsilosis were the main organisms detected. A total of 17 patients died from candidemia. The patients who were positive for C. parapsilosis, however, all survived in spite of the fact that their main treatment was only removal of the catheter (20/32 cases), while eight of 25 patients who developed fungemia due to C. albicans died from the fungemia (p = 0.001). There were no significant differences in their risk factors. Because of the better outcome for the patients who developed candidemia due to C. parapsilosis, we might be able to consider less aggressive treatment for such patients.

Adult↗

PubMed1995

Functional and anatomic evaluation of carotid atherothrombosis. A combined study of indium 111 platelet scintigraphy and B-mode ultrasonography.

We examined the relation between in vivo thrombogenicity and the morphology of carotid lesions to clarify the role of platelet deposition in carotid atherothrombosis. We evaluated 60 subjects (120 carotid bifurcations) who had at least one established risk factor for atherosclerosis by using indium 111 platelet scintigraphy and high-resolution B-mode ultrasonography. We evaluated platelet accumulation in the carotid arterial wall by means of a dual-tracer method that used In 111-labeled platelets and technetium 99m-labeled human serum albumin. The tracer accumulation was assessed both visually and semiquantitatively by using the platelet accumulation index, ie, the ratio of radioactivity of the amount of In 111-labeled platelets deposited on the vascular wall to the amount of radioactivity in labeled platelets circulating in the blood pool. The morphology of the carotid lesions was analyzed with B-mode ultrasonography in terms of the presence of ulceration, the maximum percent stenosis, the echogenicity of plaque, and the plaque score, which indicates the severity of systemic atherosclerosis. Platelet accumulation increased with increase in plaque score (P < .01), and the magnitude of platelet accumulation was significantly greater in lesions with ulceration than in those without (P < .05). The platelet accumulation index in vessels with plaque showed a very weak but significant correlation with maximum percent stenosis (r = .28, P < .05) and a stronger correlation with the unilateral plaque score (r = .42, P < .0001). Analysis of the echogenicity of plaque showed that heterogeneous plaque had a high frequency of accumulating platelets. Platelet accumulation was related to the surface characteristics and severity of carotid lesions, especially in the presence of ulceration.

Arteriosclerosis↗

PubMed1995

Ischemic stroke events and carotid atherosclerosis. Results of the Osaka Follow-up Study for Ultrasonographic Assessment of Carotid Atherosclerosis (the OSACA Study).

BACKGROUND AND PURPOSE: To clarify the clinical significance of carotid atherosclerosis for ischemic stroke events, a follow-up study was performed in Japanese patients. METHODS: Two hundred fourteen patients were registered from nine hospitals in the Osaka community. All patients were checked for a prior history of stroke, and the risk factors for stroke and atherosclerosis were evaluated. Carotid atherosclerosis was assessed by 7.5-MHz duplex ultrasonography. We studied the relationship between the ischemic stroke event rate and the severity and appearance of the carotid atherosclerosis. We also studied the relationship between stroke events and various risk factors. RESULTS: The average duration of follow-up was 16 months. Ten patients suffered new ischemic stroke episodes during this follow-up period. At the initial ultrasonographic study, 16 patients had high-grade stenosis and 21 had ulcerated plaque. Proportional hazard regression analysis showed that grade of stenosis and plaque ulceration were positively related to the event rate. Patients with ulcerated plaque had a sevenfold higher hazard ratio for stroke in comparison to those without (P < .01). The ipsilateral stroke recurrence rate was 11 times higher in patients with ulcerated high-grade stenotic carotid lesions. CONCLUSIONS: The present findings demonstrate that the severity of carotid atherosclerosis as evaluated by ultrasonography is a useful indicator of the risk of ischemic stroke in symptomatic patients.

Aged↗

PubMed1995

Perfusion imaging of the brain by B-mode ultrasonography. An experimental study in rabbits.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the ultrasonic imaging of normal rabbit brain by using echocontrast enhancer to identify the brain tissue perfusion. METHODS: A solution of SH/TA-508 (containing microbubbles of mean size 2 to 4 microns; n = 4) was used for contrast enhancement of rabbit brain tissue and was administered through the left internal carotid artery. Contrast enhancement in the ipsilateral parietal area was examined by placing a 7.5-MHz transducer on the dura after a craniectomy. Throughout the experiment, we measured parameters including arterial blood pressure, arterial blood gases, and serum glucose and hematocrit levels. We investigated whether the administration of an echocontrast enhancer would be safe for the brain tissue (n = 4). RESULTS: After injection of 100 mg/mL SH/TA-508, contrast enhancement was clearly observed within approximately 1 second in the left hemisphere (especially in the left cerebral cortex) in all animals and disappeared within 3 seconds after the end of injection. All physiological parameters remained within the normal range throughout the experiment. No focal abnormalities were observed on hematoxylin-eosin staining of the brain tissue. CONCLUSIONS: Contrast enhancement was observed in the ipsilateral hemisphere with the administration of SH/TA-508. Contrast enhancement on B-mode brain imaging would be useful for real-time identification of brain tissue perfusion and should become a promising method for bedside clinical assessment of brain tissue perfusion.

Animals↗

PubMed1995

Super-early iodine-123-iodoamphetamine SPECT imaging of human primary motor cortex.

UNLABELLED: This study was designed to visualize the motor function area related to finger movements in normal human brain using super-early (first 640 sec of acquisition) [123l]iodoamphetamine ([123I]IMP) SPECT. METHODS: Seven healthy male volunteers performed paired, isolated baseline and task sessions. The task was a right thumb-to-fingers opposition task, which was loaded for the initial 11 min of the session. A high-performance, four-head SPECT camera was used. At each session, administration of 222 MBq [123I]IMP was followed by 16 serial 160-sec dynamic SPECT acquisitions. To obtain matched brain anatomical images, MRI was also performed using the same slice formation as in the SPECT study. After image reconstruction, ROIs were set on bilateral sensorimotor hand areas (SMHA), the supplementary motor area (SMA), the frontal, temporal and occipital lobes and the cerebellar hemispheres. The percent increase of ROI activity (%INC) in the task session compared with that in the baseline session was calculated in each ROI after normalization to the global brain radioactivity. RESULTS: There was significant activation of the left SMHA by the task, the amplitude of which was maximal in the initial phase of dynamic images (the super-early phase). This area was located in the left peri-central area identified on the analogous slice in the MR image. The left SMHA showed gradual and statistically significant decrease of %INC during the three phases. CONCLUSION: Super-early [123I]IMP may be used to identify the primary motor cortex and to evaluate its function in some pathological conditions.

Adult↗

PubMed1995

[Ultrasonic assessment of cerebrovascular disease].

The aim of this paper of the symposium of the 36th Scientific Meeting of Japanese Society of Neurology is to clarify the general status of ultrasonic assessment in the imaging modality of cerebrovascular disease (CVD). Although there are many ultrasonic techniques, we want to address the carotid ultrasonography and transcranial ultrasonography. Cervical carotid atherosclerosis is known to be a major cause of brain infarction and Duplex ultrasonography is the best imaging tool. This method made it possible to visualize the living human arterial wall and to visualize the intraplaque characters. This was most advantage among several modalities. Few and really disadvantages of this method are examiner dependent results and narrow visual window. On the basis of these ultrasonic data, many investigations of nature of stroke have been performed. Transcranial ultrasonography have been accepted as a new method for non-invasive intracranial vascular imaging. There are the transcranial Doppler, transcranial tomography and the transcranial color flow imaging. Using these transcranial methods, we can evaluate the intracranial lesions. Transcranial color flow imaging made it possible to obtain real images of major arteries of circle of Willis. In conclusion, ultrasonic modality is a useful tool for assessing the risk of cerebrovascular disease or atherosclerosis, especially in chronic situations.

Aorta↗

PubMed1994

A new method for detecting beta 1,4-galactosyltransferase activity in sera of cancer patients.

A new method for assaying the activity of the enzyme that catalyzes the formation of a cancer-associated glycolipid, paragloboside (nLc4Cer), from lactotriaosylceramide (Lc3Cer) and UDP-galactose has been developed that is based on a time-resolved fluoroimmunoassay (TRFIA) with a Europium (Eu)-chelate-labeled antibody. The substrate, Lc3Cer, immobilized on a microtiter plate, was incubated with UDP-galactose, MnCl2, Triton CF-54, and the enzyme. The content of the incubation product, nLc4Cer, was determined by the TRFIA with anti-nLc4Cer monoclonal antibody H-11 as the first antibody and Eu-labeled anti-mouse IgM antibody as the second one. The lower limit of detection of nLc4Cer was estimated to be 0.2 pmol. This method was used to detect the galactosyltransferase activity in sera from patients with colorectal cancer or benign colorectal adenomas and from healthy subjects of a reference sample group. The reference interval was 0-0.25 pmol/25 microliters serum/2 h. Activity was significantly greater in patients with colorectal cancer than in those with colorectal benign adenoma (P < 0.05) and the subjects of the reference sample group (P < 0.01).

Adenoma↗

PubMed1994

An ischemic opening of the blood-brain barrier may deteriorate brain stem auditory evoked potentials following transient hindbrain ischemia in gerbils.

To clarify the effect of vasogenic brain edema on the brainstem, the relationships between waveform changes in brainstem auditory evoked potentials (BAEP) and blood-brain barrier (BBB) disturbance following transient hindbrain ischemia were investigated. Hindbrain ischemia was induced in gerbils by bilateral occlusion of the vertebral arteries. The animals were divided into three groups subjected to 0, 5, and 30 min of bilateral vertebral occlusion (BVO-0',-5', and -30' groups; n = 4 in each group). Two hours after recirculation, Evans blue (EB) solution was injected into the saphenous vein. The brains were removed after 30 min of circulation, and all areas stained macroscopically by EB were noted and recorded. During hindbrain ischemia, BAEP disappeared within 3 min. In the BVO-5' group, BAEP reappeared and returned to normal within 10 min after reperfusion, whereas in the BVO-30' group, BAEP never returned to normal and finally disappeared within 30 min after reperfusion. In the BVO-5' group, no EB staining was visible. On the other hand, in the BVO-30' group, EB staining was seen in the medial part of the tegmentum in the midbrain in two animals, and around the vestibular nucleus in the lateral parts of the pons in three. These results demonstrate the close relationship between the reversibility of ischemia-induced changes in BAEP and BBB disturbance in the brainstem.

Animals↗

PubMed1994

A new gerbil model of hindbrain ischemia by extracranial occlusion of the bilateral vertebral arteries.

A new gerbil model of hindbrain ischemia was induced by extracranial occlusion of the bilateral vertebral arteries just before their entry into the transverse foramen of the cervical vertebra. Carbon black studies, performed at 5 min after occlusion, revealed that the pons-medulla oblongata, and the cerebellum were quite ischemic in all animals. Cardiovascular changes in mean arterial blood pressure (MABP) and heart rate were recorded until 30 min after occlusion, and revealed that the typical cerebral ischemic response (i.e., abrupt increase in MABP, bradycardia, and apnea) was elicited in all animals (n = 10). Thirty minutes after occlusion, animals (n = 4) were decapitated and immersion-fixed. Brain sections were stained with hematoxylin-eosin (HE) and also immunostained for microtubule-associated protein 2 in order to evaluate ischemic neuronal damage from 30 min of ischemia. By HE staining, ischemic lesions were detected bilaterally in the oculomotor, the trigeminal motor, the lateral vestibular, and the cerebellar interpositus nucleus. In addition, immunostaining revealed ischemic lesions in several other hindbrain areas. In conclusion, we could successfully establish a new gerbil model of hindbrain ischemia. Carbon black perfusion and hemodynamic studies revealed that severe and reproducible hindbrain ischemia was produced. By histopathological examination, we could also clearly demonstrate symmetrical ischemic lesions in several hindbrain areas.

Animals↗

PubMed1994

Spontaneous non-traumatic rupture of the thoracic aorta.

Spontaneous non-traumatic rupture of the aorta is a very rare condition that requires immediate surgery. However, correct preoperative diagnosis is difficult or impossible to establish. We report a case of spontaneous aortic rupture which was successfully treated by emergency surgical exploration following a transesophageal echographic diagnosis of hemopericardium. This case, as well as other reports, suggests that hemopericardium along with symptoms which suggest aortic dissection or rupture (e.g., acute chest or back pain) should raise a strong suspicion of spontaneous aortic rupture even in the absence of intimal flap or aortic dilatation, and the emergency surgery may be life-saving.

Aorta, Thoracic↗

PubMed1994

Retrograde cerebral circulation for distal aortic arch surgery through a left thoracotomy.

We have devised a simple hypothermic retrograde cerebral circulation technique for protecting the brain during aortic arch surgery. The central venous pressure is simply elevated (15 to 18 mmHg) while the aortic arch is open and the descending aorta occluded, causing oxygen-saturated venous blood from the lower half of the body, which is undergoing deep hypothermic (15 degrees C to 18 degrees C) perfusion, to circulate in the brain in a retrograde fashion, supplying it with oxygen. Twenty-six cases of distal aortic arch aneurysm treated using this method, through a left thoracotomy with femoral vein cannulation, were evaluated. Retrograde cerebral circulation time was 59.6 +/- 13.1 minutes (40 to 93 min). Retrograde flow was 43.9 +/- 13.0 (25 to 62) mL/min. Significant oxygen and apparent lactate extraction were noted in the brain. Early death resulted in 3 of the first 14 cases (21.4%) from embolism, and in 1 of the other 12 cases (8.3%) from massive bleeding and multiple organ failure. Only one late death occurred. No death was attributed to the method itself. This method, with its simplified operative procedure using a lateral thoracotomy, supplied oxygen to the brain and protected it during interruption of the cerebral circulation. Careful management of the atherosclerotic aorta is needed.

Aged↗

PubMed1994

Effects of hemodialysis on cerebral circulation evaluated by transcranial Doppler ultrasonography.

BACKGROUND AND PURPOSE: The effects of hemodialysis on the cerebral circulation of humans and the correlation between changes in blood flow velocity in the basal cerebral arteries and those of several physiological variables influenced by hemodialysis have been inadequately studied. METHODS: Blood flow velocities were obtained from the middle cerebral artery and the basilar artery by transcranial Doppler ultrasonography in 27 patients receiving chronic maintenance hemodialysis immediately before and after the procedure. Changes in body weight, hematocrit, blood pressure, and arterial blood gases were recorded simultaneously. RESULTS: There was a significant reduction in mean flow velocity in the middle cerebral artery (P < .01) and the basilar artery (P < .01) after hemodialysis. We observed a significant negative correlation between the relative change in mean flow velocity and the loss of weight after hemodialysis, the amount of fluid removed, and the increase in hematocrit in the middle cerebral artery and the basilar artery. CONCLUSIONS: Hemodialysis and the associated physiological changes can significantly affect the cerebral circulation. Blood flow velocities in the middle cerebral artery and the basilar artery decrease significantly with hemodialysis. The loss of body weight, the amount of fluid removed, and the change in hematocrit significantly correlate with the change in mean flow velocity. The transcranial Doppler method can effectively monitor rapid changes in the cerebral circulation during potentially harmful procedures.

Adult↗