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Biomedical subjects

S Nakazawa

Publications and source records attributed to S Nakazawa.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Electrophysiologic evaluation of passive and active attentions--II. Developmental changes of somatosensory event-related potentials in different attentive paradigms].

By somatosensory event-related potentials (SERP) we have previously demonstrated in adults that an enhanced positivity of P 250 is statistically significant at the frontal region during the active attentive state. We have also evaluated developmental changes of P 250 during different attentive states: passive and active. In this study, 30 healthy children (5-16 years of age) and six healthy adults (23-41 years) were required to perform the following four paradigms: passive attentive, active attentive, control, and oddball. SERP were recorded at Fz, Cz and Pz. In the passive attentive paradigm, P250 amplitude at Fz, Cz and Pz remained constant irrespective of age. With regard to the topography of the amplitude, however, P 250 was distributed dominantly at Pz in Group 1 (5-6 years of age) and Group 2 (7-11 years), contrary to the dominance at Cz in both Group 3 (12-16 years) and adults. In the active attentive paradigm, on the other hand, the P 250 amplitude at Fz reached its minimum at about 10 years and then increased until the adulthood. With respect to the topography of the amplitude, P 250 was distributed dominantly at Pz in Groups 1 and 2, at Cz in Group 3, and at Fz and Cz in adults. These results suggest that the topographic changes in the active attentive paradigm are dependent upon the developing abilities to expect the next stimulus and to maintain awareness.

Adolescent↗
PubMed1998

[Traumatic aortic regurgitation: report of two surgical cases].

Two successful surgical cases with aortic regurgitation due to blunt trauma are reported. Case 1: A 48-year-old female was transferred to our hospital after a traffic accident. She was intubated and mechanically ventilated. Twelve days later, echocardiography demonstrated massive aortic regurgitation. The next day, aortic valve replacement was performed using a 21 mm SJM mechanical valve. The central part of the non-coronary cusp was torn and perforated 15 mm long. She is in good condition three years after surgery. Case 2: A 57-year-old male was transferred to the nearest hospital because he was involved in a snowslide accident. A month after the injury, catheterization showed massive aortic regurgitation and pulmonary hypertension. An aortotomy revealed that the intima around the right coronary ostium was completely torn. A perforation with a diameter of 3 mm was also observed on the right coronary cusp. After coronary cusps were excised, interrupted mattress sutures buttressed with pledgets were passed through the aortic wall at the distal level of the intimal laceration and then to the aortic annulus. A 25 mm SJM prosthetic valve was seated at the aortic ring. As the right coronary ostium was included in the plicated aortic wall, aortocoronary bypass was constructed using the great saphenous vein. He is doing well 14 months after surgery. Aortic regurgitation due to blunt trauma is rare and difficult to diagnose. Sometimes cardiac failure progresses rapidly. Therefore, urgent surgery is recommended as soon as the diagnosis is confirmed.

Aortic Aneurysm↗
PubMed1998

[Diagnosis of the wall-thickened lesions of the gallbladder with dynamic MRI].

We studied 32 patients with the thickened lesions of the wall of the gallbladder by using dynamic MRI. We tried the differential diagnosis of gallbladder lesions according to the time intensity curve (TIC) and enhanced pattern. TIC of carcinoma was elevated more seeply from plain to arterial phase than the inflammatory diseases. The Inflammatory diseases were keeping three-layer structures of the wall of the gallbladder, but gallbladder carcinoma destroys the wall-structure. We could diagnose as direct liver invasion of the carcinoma clearly. We could exactly diagnose adenomyomatosis in dynamic MRI by small low intensity spots within the wall of the gallbladder. In the patients with gall stones, the wall of the gallbladder were more clearly observed in dynamic MRI compared with US and EUS.

Carcinoma, Adenosquamous↗
PubMed1998

[Application of ultrasound method for hemorrhagic digestive disease].

Ultrasonography for the digestive diseases are consisted of abdominal ultrasonography (US), endoscopic ultrasonography (EUS) and color Doppler endoscopic ultrasonography (CDEUS). These play a supplementary role in comparison with the roentgenography and endoscopy. The information of the ultrasonography is different from these examinations. By US the collateral shunts of esophago-gastric varices are observed. EUS is useful for diagnosis of the properties of esophago-gastric varices and judgement of effects of treatment for these varices, gastric ulcer and vessels in ulcer base and hemorrhagic bowel diseases. CDEUS can show blood streams of esophago-gastric varices and hemorrhagic ulcer.

Duodenal Ulcer↗
PubMed1998

[Diagnosis of depth of invasion of gallbladder carcinoma with endosonography].

We reported on the usefulness of endosonography (EUS) in the diagnosis of the depth of invasion of gallbladder carcinoma. We performed EUS on 69 patients with gallbladder carcinoma: the degree of tumor extension in 17 was m (tumor invading the mucosa), in 5 pm (tumor invading the muscular layer), in 21 ss (tumor invading the subserosa), 14 in se (tumor invading the serosa), and 12 si (tumor extending to adjacent organs). The detection rate of tumors with EUS was 91.3% (63 of 69). All 6 (100%) patients with pedunculated lesions (Ip type) were correctly diagnosed with EUS. Eighteen of 21 patients (85.7%) with broad-based elevated tumors (Is type), and 5 of 7 (71.4%) with flat-elevated lesions (IIa type) were also diagnosed correctly. EUS is a useful modality for the diagnosis of gallbladder carcinoma. In particular, EUS diagnosis of the depth of invasion is reliable in Ip-type lesions. It is recommended that patients with Ip-type lesions undergo laparoscopic cholecystectomy, but in patients with Is-or IIa-type lesions conventional cholecystectomy with lymph node resection should be performed.

Adult↗
PubMed1997

A domain for G protein coupling in carboxyl-terminal tail of rat angiotensin II receptor type 1A.

To delineate domains essential for Gq protein coupling in the C-terminal region (C-tail) of rat angiotensin II (Ang II) receptor type 1A (AT1A), we modified the putative cytosolic regions of the receptor by truncation or alanine substitution and determined resultant changes in the guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) effect on Ang II binding and inositol trisphosphate production by the agonist. Independently, we studied the effect of synthetic C-tail peptides (P-5) and its alanine substitution analogs on [35S]GTPgammaS binding to Gq. Effects of GTPgammaS on Ang II binding (shift to a low affinity form) and inositol trisphosphate production in the deletional mutant receptor 1-317 AT1A was similar to wild type AT1A, whereas in shorter C-terminal deletion mutants 1-309, 1-311, 1-312, 1-313 AT1A, and substitutional mutants Y312A, F313A, and L314A these activities were markedly reduced. The binding of [35S]GTPgammaS to Gq was promoted by the synthetic C-terminal peptide P-5 but not when mutated at Tyr312, Phe313, or Leu314. Results indicate that Tyr312, Phe313, and Leu314 in cytosolic carboxyl-terminal region of rat AT1A are essential for coupling and activation of Gq.

Amino Acid Sequence↗
PubMed1997

DNA damage-associated dysregulation of the cell cycle and apoptosis control in cells with germ-line p53 mutation.

Lymphoblastoid cell lines (LCLs) with heterozygous p53 mutations at residues 286A, 133R, 282W, 132E, and 213ter were established from five independent Li-Fraumeni syndrome families. When cell cycle regulation in response to gamma-irradiation was studied, these LCLs showed an abnormal G1 checkpoint associated with defective inhibition of cyclin E/cyclin-dependent kinase 2 activity in all cases except for 282W LCL, which showed a normal G1 checkpoint. On the other hand, the control of S-phase-G2 as determined by cyclin A/cyclin-dependent kinase 2 activity was defective in all these LCLs. The mitotic checkpoint was also defective in the two LCLs analyzed as either competent or incompetent for G1 arrest. When radiation-induced apoptosis, which requires wild-type p53 function under optimal conditions, was studied, all of these LCLs showed significant failure compared to normal LCLs. These findings indicate that although p53-dependent transactivation and G1-S-phase cell cycle control are variably dysregulated, the induction of apoptosis and control of the cell cycle at S-phase-G2 and the mitotic checkpoint in response to DNA-damaging agents are consistently dysregulated in heterozygous mutant LCLs. This suggests that these dysfunctions underlie, at least in part, the susceptibility of Li-Fraumeni syndrome families to cancer. Furthermore, the approach presented is a potentially useful method for studying individual carriers of different germ-line p53 mutations and different biological features.

Adolescent↗
PubMed1997

Increased plasma cholesteryl ester transfer activity in obese children.

To determine whether enhanced activity of cholesteryl ester transfer protein (CETP) contributes to the development of atherogenic lipoprotein profiles in obese children, plasma CETP activity was assayed according to a micro-method, by co-incubating lipoprotein-deficient samples with exogenous donor and acceptor lipoproteins. The study subjects were 31 obese children (14 males and 17 females). Serum levels of triglycerides, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), TC:high-density lipoprotein (HDL)-C, LDL-C:HDL-C, apolipoprotein (apo) B, and apo B:apo Al were increased in obese children. Thus they appeared to exhibit an atherogenic lipoprotein profile, with a relative decrease in cholesterol carried by HDL compared with the cholesterol in the other lipoprotein fractions. The mean fasting plasma insulin level was also increased. CETP activity was significantly higher in the obese children than in nonobese control children, and was correlated with LDL-C, TC:HDL-C, LDL-C:HDL-C, and apo B:apo Al. These results suggest that an increase in plasma CETP activity results in atherogenic change in lipoprotein metabolism in obese children. The increase in CETP may be due to the adiposity or insulin resistance. Alternatively, dyslipidemia per se, physical inactivity or excessive fat intake, that are commonly found in obese children, may contribute to the increase in CETP activity.

Adolescent↗
PubMed1997

New age-adjusted measure of body fat distribution in children and adolescents: standardization of waist-hip ratio using multivariate analysis.

OBJECTIVE: To explore a new anthropometric index of body fat distribution adjusted for ages ranging from 6-15 y in both boys and girls. DESIGN: Sex, age, and 11 anthropometric variables were subjected to principal component analysis. Based on these results, we developed a new anthropometric index, namely an age-adjusted measure of body-fat distribution. This index was evaluated statistically for suitability of use in epidemiological surveys. SUBJECTS: Japanese children, including obese and nonobese subjects, in one elementary and one junior high school in Yamanashi Prefecture, Japan: 508 boys and 549 girls whos ages ranged from 6 y 1 mon-15 y. MEASUREMENTS: Measurements included the height (Ht), body weight, circumference of the waist, hip and thigh. Body mass index, the ratios of the waist, hip or thigh to the Ht, waist-hip ratio (WHR) and waist-thigh ration were calculated. RESULTS: The first principal component (PC 1) accounted for 49.8% of the total variation, and was interpreted as an indicator of the general size on an individual. PC 2 accounted for 25.9%, and was interpreted as a shape measure that indicates body fat distribution. Calculation of WHR/Ht, a parameter that represented PC 2 adjusted by PC 1, gave an highly robust linear regression equation for age by gender. The residuals from the regression line for WHR/Ht deviated from normal distribution only in the boys, whereas the mean residual was nearly zero and distribution of the residuals was similar in three age subgroups by gender, supporting the use of the common standard deviation score in all age groups as an indicator of body fat distribution. CONCLUSION: The common standard deviation score of WHR/Ht can serve as an epidemiological index of body fat distribution adjusted for ages between 6 and 15 y.

Adipose Tissue↗
PubMed1997

Three-dimensional intraductal ultrasonography: preliminary results of a new technique for the diagnosis of diseases of the pancreatobiliary system.

BACKGROUND AND STUDY AIMS: Intraductal ultrasonography (IDUS) is a useful method for the diagnosis of pancreatobiliary diseases, but the images obtained using the presently available ultrasonic probes are limited by their two-dimensional nature and are sometimes difficult to interpret. The possible application of three-dimensional intraductal ultrasonography (3 D-IDUS) to facilitate the diagnosis of pancreatobiliary disease was therefore studied using a newly developed system. PATIENTS AND METHODS: 3 D-IDUS of the biliary system was performed on 26 patients with benign (n = 100) or malignant pancreatobiliary diseases (n = 16), via percutaneous transhepatic or peroral approaches. Three-dimensional diagnoses were made using both radial and linear images generated on the monitor of this system along with a comparison with conventional IDUS (2 D-IDUS) findings. RESULTS: The courses of vessels surrounding the bile duct could be easily imaged in all cases, and accurate assessment of tumor extension and the relationship with surrounding organs could be achieved for all the malignancies. In four of six cases of bile duct cancers the whole outline of the tumor could be visualized so that the tumor volumes could be measured. CONCLUSIONS: These preliminary results of 3 D-IDUS in the pancreatobiliary system, the first to be reported in the English literature, indicate that this new system has clear advantages over the 2 D-IDUS approach for diagnostic purposes. Further technical improvements can be expected which will ensure a clinical role for 3 D-IDUS.

Adult↗
PubMed1997

A case of recessive X-linked ichthyosis: scale-specific abnormalities of lipid composition may explain the pathogenesis of the skin manifestation.

We analyzed the lipid content of the scales, red blood cells, and plasma from a recessive X-linked icthyosis patient. The patient's scales accumulated cholesterol sulfate, had decreased levels of free sterols, sterol esters and sphingolipids, and lacked phospholipids. Although the accumulation of cholesterol sulfate was found in the patient's red blood cells and plasma as well as in the scales, other lipid composition abnormalities were specific for scales. Such scale-specific abnormal lipid composition may explain the pathogenesis of generalized hyperkeratosis and abnormal scaling of the disease.

Adult↗
PubMed1997

Ictal EEG and single photon emission computed tomography in a patient with cortical dysplasia presenting with atonic seizures.

PURPOSE: Ictal studies of atonic seizures in children with epilepsy are rare. To clarify the neurophysiologic mechanism of such seizures, we describe a cluster of atonic seizures in a 6-year-old girl with cortical dysplasia. METHODS: Ictal activity was recorded as slow-wave bursts beginning over the right frontocentral regions, where the cortical dysplasia was detected by magnetic resonance imaging (MRI), and propagating to the left hemisphere. RESULTS: The polygraphic recording demonstrated that the atonia indicated by the sudden interruption of electromyogram (EMG) discharges corresponded to the bilaterally synchronous spike-and-wave complexes. An ictal single photon emission computed tomography (SPECT) study with 99mTc hexamethyl propylene amine oxime ([99mTc]HMPAO) simultaneously performed during EEG recording showed marked bilateral mesial frontal and right frontoparietal hyperperfusion. CONCLUSIONS: Our findings suggest that the neurophysiological mechanism of the atonic seizures may be produced by a strong inhibition in the bilateral motor cortexes. Ictal SPECT is valuable in demonstrating the pathophysiology of both atonic seizures and secondary bilaterally synchronous spike-and-wave complexes in the EEG.

Cerebral Cortex↗
PubMed1997

[Isolation of verotoxin-producing Escherichia coli from cattle and characterization of the isolated strains].

Attempts to isolate Verotoxin-producing Escherichia coli (VTEC) from 53 dead baby cattle were made during a period from January 1989 to July 1991. From 6 cattle of 5 farms, VTECs were isolated. Further examination of cattle from 2 farms with dead baby cattle and from 1 farm with an outbreak of diarrhea among baby cattle, from 8 of 26 cattle with diarrhea and from 9 of 58 healthy cattle, VTECs were isolated. Several serotypes which caused food poisoning in Japan as well as in the US and Europe were included in the isolated strains. VTECs were also isolated from several cattle imported from the US suggesting that these VTECs were from outside the country together with the imported cattle.

Animals↗
PubMed1997

[A lateral fluid percussion model for the experimental severe brain injury and a morphological study in the rats].

Few morphological studies have been reported on fluid-percussion experimental models using mechanically induced severe brain injury have been reported. This study was initiated to evaluate microscopic and immunohistochemical findings in severe brain injury models using rats. The experimental rats and the methods used were the same as described for a fluid-percussion model. Fluid-percussion models of traumatic brain injury were produce by rapidly injecting fluid volume into the epidural space of the temporal lobe. We used 5 rats which sustained various degrees of injury by high (7.0 atm), medium (5.6 atm) and low (3.5 atm) magnitudes of impact and sham control. The rats were sacrificed and perfused transcardially with buffer solution followed by 2.5% glutaraldehyde at intervals of 24 hours, 3 days, and 7 days, and there were normal and sham control groups. In this immunohistochemical study, monoclonal antibody to 70 kilodalton neurofilament subunit was used in a standard Avidin-Biotin Complex Kit (DAKO). Microscopic findings revealed subarachnoid hemorrhage, lateral IIIrd ventricular hemorrhage, and rarefaction and petechial hemorrhage of the local contusional lesion. In the medium level injury, there was a marked petechial hemorrhage in the corpus callosum and subependymal area. In the high level injury, there was marked edema in the white matter of the ipsi- and contralateral cerebral hemisphere, and multiple petechial hemorrhage in the brain stem and cerebellum. Microscopic findings in the corpus callosum, subependyma and brain stem in the vicinity of petechial hemorrhage revealed a large number of axonal swellings, but in these specimens only a few typical axonal retraction balls were seen with Bodian and immunohistochemical stains. In conclusion, this experimental model seems to simulate local and diffuse shearing injury, showing various morphological characteristics of diffuse axonal injury.

Animals↗
PubMed1997

Restoration of seminiferous tubular function after discontinuation of long-term gonadotropin-releasing hormone agonist administration in premature male rats.

We examined whether seminiferous tubular function develops normally after discontinuation of long-term gonadal suppression in premature male rats. Wistar male rats 4 weeks old were subjected to the injection of gonadotropin-releasing hormone (Gn-RH) agonist or normal saline solution as control for 12 weeks. The rats were sacrificed 0 and 6 weeks after discontinuation of the treatment. Histological examinations of the seminiferous tubules immediately after cessation of the Gn-RH agonist treatment demonstrated a stage-related change in specific germ cells. Seminiferous tubules of Gn-RH agonist-treated rats were narrow and irregular in shape, and contained significantly fewer spermatids and pachytene spermatocytes at stages VII to XIV than those in controls. A complete development of spermatogenesis was histologically observed 6 weeks after cessation of the treatment. Leydig cells became atrophic without any reduction in cell number immediately after the treatment, but Leydig cells grew rapidly and were similar in appearance to those in control rats 6 weeks after cessation of the treatment. Serum testosterone concentrations were noticeably suppressed immediately after cessation of the treatment (P < 0.01 vs. control) and reached a similar level to those of controls 6 weeks after the cessation. Testes weights were significantly lower in Gn-RH agonist-treated rats than in control rats and had not fully developed 6 weeks after cessation of the treatment (P < 0.01 vs. control). These results suggest that the testicular function develops normally after cessation of the long-term gonadal suppression in premature rats, although the increase in testicular weight may be slightly influenced.

Animals↗
PubMed1997

Role of IGF binding protein-1 in the dawn phenomenon and glycemic control in children and adolescents with IDDM.

OBJECTIVE: To clarify the involvement of IGF binding protein (IGFBP)-1 in the dawn rise in plasma glucose and in the overall glycemic control in patients with IDDM. RESEARCH DESIGN AND METHODS: Seventy patients with IDDM were divided into three groups according to pubertal development. Blood samples were obtained for measuring plasma glucose, IGFBP-1, and free insulin at 2200, 0500, and 0700 over a 2-day period. Levels of HbA1c, IGF-1, and IGFBP-3 were determined at 0700. Urinary growth hormone (GH) was collected overnight. To examine its frequency, the dawn phenomenon was defined on the basis of the following: 1) change in plasma glucose from 0500 to 0700, 2) plasma glucose level at 0700, and 3) no antecedent hypoglycemia. RESULTS: There was a statistically significant link between the dawn changes in plasma glucose and IGFBP-1 (r = 0.37, P < 0.01). The former was not related to the change in free insulin or to the overnight urinary GH level. In stepwise regression analyses, plasma glucose at 0700 = 0.03 IGFBP-1 (P < 0.01) + 0.525 HbA1c (P < 0.01) + 3.696 (R2 = 51%). Approximately half of the patients in each group exhibited the dawn phenomenon; 38% of patients with HbA1c < 8% also showed the dawn phenomenon. CONCLUSIONS: We have demonstrated a statistically significant link between the morning risk in IGFBP-1 and plasma glucose. The free fraction of IGF-1 modulated by acute changes in IGFBP-1 may play a direct role. The dawn phenomenon may occur regardless of pubertal stage or glycemic control in children and adolescents with IDDM.

Adolescent↗