Search PubMed⌕ Search

Biomedical subjects

T Kusaka

Publications and source records attributed to T Kusaka.

At least 19 recordsLinked to original sources
PubMed2001

Functional imaging of the brain in sedated newborn infants using near infrared topography during passive knee movement.

Near infrared topography was used for functional imaging of the sensorimotor cortex of newborn infants during passive knee movement under sedated sleep. Contralateral knee movement caused a marked increase in oxyhemoglobin and total hemoglobin from the baseline values at almost all locations in the primary sensorimotor area of all neonates and a decrease in local deoxyhemoglobin in six of seven neonates. During ipsilateral knee movement, oxyhemoglobin and total hemoglobin showed slighter changes at a few locations, equal to 30% (mean) and 29% (mean) of the changes that occurred with contralateral stimulation, respectively. The mean times corresponding to maximal changes were 11.9 s for oxyhemoglobin and 19.1 s for deoxyhemoglobin, demonstrating that oxyhemoglobin has a much faster response than does deoxyhemoglobin.

Brain Mapping↗
PubMed2001

Estimation of regional cerebral blood flow distribution in infants by near-infrared topography using indocyanine green.

Near-infrared topography with indocyanine green was used to measure regional cerebral blood flow (rCBF) in the temporal lobes of infants. The mean rCBF in infants without neural abnormality was 14.5 +/- 3.1 ml/100 g/min, and the rCBFs in the fronto-temporal, temporal, and occipito-temporal regions were 15.1 +/- 3.9, 15.4 +/- 3.3, and 14.6 +/- 3.3 ml/100 g/min, respectively. Moreover, in one asphyxiated infant with infarction and one infant with subdural and intracerebellar hemorrhage, it was demonstrated that the area of defective blood flow could be detected as well as it can by SPECT. This technique makes it possible to estimate rCBF distribution in infants at the bedside. Thus, in the future, evaluation of various neonatal illnesses should be feasible.

Asphyxia Neonatorum↗
PubMed2001

Genetic analysis of a local recurrent tumor after colonic polypectomy.

After polypectomy, the cut end of the polyp is usually examined by light microscopy to assess the risk of recurrent cancer. Here, we report a recurrent tumor that appeared in the colon 6 years after polypectomy, although cancer cells were not observed in hematoxylin and eosin-stained sections of the cut end of the primary polyp. Retrospectively, the primary polyp and the recurrent tumor were analyzed for mutations of the p53 gene. We detected p53 mutations in the primary polyp, even in the cut end of the polyp. The same set of two p53 mutations was detected in the recurrent tumor. These observations indicate a common origin of the primary tumor and the recurrent tumor. We conclude that it is important to analyze p53 mutations in colonic polyps, especially when the cut end of the polyp is difficult to evaluate histologically, in order to predict recurrence.

Adenocarcinoma↗
PubMed2001

Differences in transcutaneous bilirubin readings in Japanese term infants according to feeding method.

BACKGROUND: Controversy has existed for many years over whether infant feeding methods are related to serum bilirubin concentrations during the first few days of life. Differences in initial jaundice patterns according to the feeding method until 72 h after birth have not been elucidated hitherto. The difference may become clear in Japanese neonates because jaundice shows a much higher peak bilirubin concentration and a later peak in Japanese neonates than in Caucasian neonates. METHODS: In the present study, we investigated variations in the transcutaneous bilirubin reading (TcB) obtained within 72 h after birth among 177 breast-fed and 494 formula-fed healthy Japanese term neonates. RESULTS: There was no difference between TcB in formula-fed and breast-fed infants until the first 30 h, after which time the rate of increase in TcB was lower in formula-fed infants. Among breast-fed neonates, a good linear regression between time after birth and TcB was maintained. Similarly, weight losses in breast-fed infants at 24-48 h and 48-72 h after birth were greater than those in formula-fed infants. CONCLUSIONS: The jaundice pattern in Japanese neonates from 30 to 72 h after birth according to the feeding method was different from that in Caucasian neonates.

Asian People↗
PubMed2001

Cerebral metabolism and regional cerebral blood flow during moderate systemic cooling in newborn piglets.

BACKGROUND: Clinical trials of hypothermic therapy in asphyxiated infants have started recently. However, clinical studies have been delayed by the difficulty in selecting infants with a bad neurological prognosis and by the concern regarding adverse effects of hypothermia. The purpose of this study is to examine the effects of systemic cooling on cerebral metabolism (CMR) and the regional cerebral blood flow (rCBF) in newborn piglets. METHODS: The rCBF in the seven parts of the brain were measured with colored microspheres. The blood samples for the measurement of cerebral oxygen consumption (CMRO2) and cerebral glucose consumption (CMRglc) was collected from the umbilical artery and the superior sagittal sinus. RESULTS: Reductions of cerebral cortex temperature to 32 degrees C decreased blood flow in all brain regions. In particular, blood flow in the brainstem decreased more significantly than in any other region. The total cerebral blood flow (CBF), CMRO2 and CMRglc, respectively, decreased to 32.3+/-3.9 mL/100 g per min, 2.8+/-1.0 mLO2/100 g per min and 22+/-12 mmol/100 g per min at 32 degrees C (41, 53 and 46% of the initial value). The CBF decreased in parallel with CMRO2 and CMRglc down to 35 degrees C, but CBF decreased to a greater extent than CMRO2 and CMRglc at below 35 degrees C. CONCLUSIONS: The indication of hypothermic therapy and the degree of cooling have to be performed very carefully. Systemic cooling is especially dangerous for the total asphyxiated infants who might have damage to the brainstem because the blood flow in the brainstem has significantly decreased during hypothermia.

Animals↗
PubMed2001

Time of closure of ductus venosus in term and preterm neonates.

AIM: To investigate the relation between gestational age, birth weight, and antenatal corticosteroid administration and the time of ductus venosus closure. METHODS: Ninety eight neonates of 30-41 weeks gestational age were studied by daily ultrasonography until ductus venosus closure. RESULTS: In neonates of 30-33 weeks gestational age, the ductus venosus closed at 6.0 (2.4)days (mean (SD)); in those of 34-36 weeks gestational age, it closed at 6.1 (2.8) days; and in those of 37-41 weeks gestational age, it closed at 4.2 (2.1) days. The effect of antenatal administration of corticosteroids on the time of closure was also investigated in neonates of 30-34 weeks gestational age. Closure occurred by 5.5 (2.4) days in the group given corticosteroids compared with 7.5 (2.1) days in the remainder. CONCLUSIONS: The ductus venosus closed sooner after birth in neonates of greater gestational age or higher birth weight. Antenatal corticosteroid administration had a significant effect in promoting closure.

Birth Weight↗
PubMed2001

Alcohol consumption and frontal lobe shrinkage: study of 1432 non-alcoholic subjects.

OBJECTIVES: To evaluate the influences of chronic alcohol consumption on brain volume among social drinkers, as it is well known that alcohol misusers have a high risk of brain shrinkage. METHODS: Frontal lobe volumes on MRI were compared with the current alcohol habits of consecutive 1432 non-alcoholic subjects. RESULTS: After adjusting for other variables, age was found to be the most powerful promoting factor for the shrinkage with a odds ratio of 2.8 (95% confidence interval (95% CI) 1.23-3.06) for each 10 years of age. Regarding alcohol habit, 667 of the subjects were abstainers, and 157, 362, and 246 of the subjects were light (average 88.2 g ethanol/week), moderate (181.2 g/week), and heavy (418.1 g/week) drinkers, respectively. Moderate alcohol consumption did not increase the incidence of frontal lobe shrinkage (odds ratio 0.98; 95% CI 0.73-1.33), whereas heavy drinkers were at a higher risk compared with abstainers (1.80; 1.32-2.46). The contributory rate of alcohol consumption for frontal lobe shrinkage was 11.3%. CONCLUSION: The brain tends to shrink physiologically with age. Heavy alcohol consumption seems to exaggerate this shrinkage in social drinkers. Moderate alcohol consumption does not seem to affect brain volume.

Adult↗
PubMed2001

Characterization of specific [3H]nociceptin binding in rat brain and spinal cord.

The present study was undertaken to characterize simultaneously [3H]nociceptin binding to opioid receptor-like 1 (ORL1) receptors in the rat brain and spinal cord. Specific binding of [3H]nociceptin to crude membranes from the rat brain and spinal cord at 25 degrees C was saturable, reversible and of high affinity, and it also exhibited a pharmacological specificity involving the ORL1 receptor. The Kd and Bmax values for [3H]nociceptin in the spinal cord were significantly lower than those in the brain. At 4 degrees C, there was a significant increase in the dissociation constant (Kd) for [3H]nociceptin in the brain and spinal cord with little change in the maximal number of binding sites (Bmax) compared with that at 25 degrees C. Nociceptin and its analogue, [Phe1 psi(CH2-NH)-Gly2]nociceptin(1-13)NH2 were found to be potent inhibitors of [3H]nociceptin binding to crude membranes from the brain and spinal cord, while opioid ligands such as naloxone-benzoylhydrazone, naltrindole and nor-binaltorphimine, exhibited an inhibitory effect only at high concentrations. The Ki values for nociceptin, its analogue and opioid ligands in the spinal cord were significantly lower than those in the brain. There were regional variations in the specific [3H]nociceptin binding to crude membranes from the rat brain: a relatively high density of [3H]nociceptin binding in the cerebral cortex, hippocampus, thalamus and midbrain, moderately dense binding in the corpus striatum and pons/medulla oblongata, and the lowest density of binding in the cerebellum. In conclusion, the present study has shown that [3H]nociceptin binds selectively to ORL1 receptors in the rat brain and spinal cord.

Animals↗
PubMed2001

Relationships between serum (ZZ)-bilirubin, its subfractions and biliverdin concentrations in infants at 1-month check-ups.

In 150 infants, including those with breast milk jaundice, who were brought to our hospital for their 1-month check-ups, the serum concentrations of (ZZ)-bilirubin, its subfractions and biliverdin were measured by high-performance liquid chromatography and the relationships among them investigated. (ZZ)-Bilirubin was found to have the highest serum concentration, followed by (ZE)-bilirubin, accounting for 14.0 (geometric mean) % of (ZZ)-bilirubin. Biliverdin had a serum concentration of 0.95% of (ZZ)-bilirubin. There was only a small amount of total (di- and mono-) glucuronosyl bilirubin, 0.42% of (ZZ)-bilirubin. (ZE)-Bilirubin, (EZ)-bilirubin, (EZ)-cyclobilirubin. biliverdin, diglucuronosyl bilirubin and monoglucuronosyl bilirubin (C-8 and C-12) showed positive logarithmic correlations with (ZZ)-bilirubin (R2=0.16 or above, P<0.05). (ZE)-Bilirubin showed a significant positive logarithmic correlation with (ZZ)-bilirubin (R2=0.863, P<0.0001). Furthermore, (EZ)-cyclobilirubin, the most important photoisomer in phototherapy for neonatal hyperbilirubinaemia, was detected in very small amounts in approximately half of the neonates (84 of 150) when they were in conditions of only weak ambient light. The relationship between total glucuronosyl bilirubin and (ZZ)-bilirubin concentrations fitted a model of saturation kinetics of bilirubin UDP-glucuronosyltransferase.

Bilirubin↗
PubMed2000

Analysis of K-ras codon 12 mutations and p53 overexpression in colorectal nodule-aggregating tumors.

BACKGROUND AND AIMS: Morphologically, colorectal nodule-aggregating tumors are quite different from polypoid-type colorectal tumors that develop via the adenoma-carcinoma sequence. Although polypoid-type colorectal tumors are well known to have a high incidence of K-ras gene mutation and p53 overexpression, colorectal nodule-aggregating tumors have not been examined in terms of genetic changes and clinicopathological features. In the present study, therefore, we analysed the clinicopathological features, genetic changes in K-ras codon 12, and p53 overexpression in colorectal nodule-aggregating tumors. METHODS: A total of 18 colorectal nodule-aggregating tumors were surgically resected and then analysed clinicopathologically. Immunohistochemistry and polymerase chain reaction-single stranded conformational polymorphism were performed to analyse p53 abnormalities in the tumors. K-ras codon 12 mutations were screened out by the polymerase chain reaction-restriction fragment length polymorphism method and analysed by fluorescence direct sequencing. RESULTS: p53 overexpression was observed in six lesions (33%). p53-overexpressing cells were observed in parts of carcinoma or adenoma showing high-grade atypia. Four of the 10 (40%) samples had a p53 gene mutation. Nine of the 18 (50%) samples had a K-ras codon 12 point mutation. In eight cases (89%), the mutations of the K-ras codon 12 were of the same type: GGT (glycine) to GTT (valine). CONCLUSIONS: The colorectal nodule-aggregating tumor has distinctive characteristics showing a morphological phenotype of the superficial-type tumors and genotype of the polypoid tumors in terms of K-ras gene mutation and p53 overexpression.

Adenoma↗
PubMed2000

Changes in cerebral hemoglobin concentration and oxygen saturation immediately after birth in the human neonate using full-spectrum near infrared spectroscopy.

Using full-spectrum near infrared spectroscopy (fsNIRS), we measured changes in oxy- and deoxyhemoglobin (HbO2 and Hb), total hemoglobin (T-Hb) concentration, and hemoglobin oxygen saturation (SbO2) in the brain tissue of seven neonates immediately following birth. It was found that HbO2 rose rapidly within 2-3 min after birth. During the same time, there was a transient increase in T-Hb concentration, after which it decreased together with Hb. SbO2 increased rapidly after birth, from 18% at 1.5 min to about 55% at 5-6 min, followed by a gradual increase of about 10%. Oxygenation in the brain occurred much sooner in three subjects given oxygen for a short time immediately after birth than in those who did not receive oxygen. This preliminary study indicated that dynamic changes occur in cerebral circulation and oxygenation as part of the physiological changes taking place soon after birth.

Brain↗
PubMed2000

Effects of bilirubin and its photoisomers on direct bilirubin measurement using bilirubin oxidase.

We examined the reactivity of human serum albumin-bound bilirubin and its photoisomers as substrates for a direct bilirubin assay using bilirubin oxidase. The reduction of (EZ)-cyclobilirubin reached 100% 5 min after addition of the enzyme at any pH tested (3.5-7.4) in 0.1 mol/L phosphate buffer, whereas the reduction of (ZE)-bilirubin or (ZZ)-bilirubin reached 100% only below pH 4.5 or 5.5, respectively. (ZZ)-Bilirubin and its photoisomers did not react in citrate-lactate buffer at pH 3.7. The circular dichroism spectrum of (ZZ)-bilirubin in this buffer did not show a positive Cotton effect. These results indicate that a three-dimensional structure surrounding the reaction site of bilirubin is important for the reactivity with bilirubin oxidase.

Bilirubin↗
PubMed2000

[Histopathological diagnosis in reflux esophagitis].

We reviewed the histopathological features for the diagnosis of reflux esophagitis and gastroesophageal reflux disease(GERD) including carcinogenesis of the esophagus. Histologically, the presence of capillary dilatation, elongation of papillary, hyperplasia of basal layer, inflammatory cells-infiltration, balloon cells in the epithelium, and ulceration were evaluated in GERD cases. Although, histopathological changes were not clear in endoscopic-negative GERD cases, immunohistochemical examination with cell cycle protein(PCNA, p21, and p27) revealed the same abnormalities with GERD cases. In Japan, the majority cases of GERD are evaluated in grade according to Los Angeles system, therefore the prevalence of Barrett's esophagus and cancer is very low. We hypothesize that esophageal squamous cell carcinoma arising from GERD different from Barrett's cancer sequence, and clinicopathological long-term follow up will be required to assess the carcinogenesis including gene analysis.

Barrett Esophagus↗
PubMed2000

Prevention of lymphocyst formation following systematic lymphadenectomy.

BACKGROUND: The occurrence of pelvic lymphocysts is an important complication following systematic lymphadenectomy for gynecological malignancies. We employed a procedure to prevent vaginal shortening following radical hysterectomy and we examined whether this procedure could be effective in preventing pelvic lymphocyst formation. METHODS: We studied the incidence of lymphocysts in 190 patients with 84 cervical cancers, 74 endometrial cancers and 32 ovarian cancers, using computed tomographic examination at 3 and 6 months subsequent to the surgery. The surgery included radical hysterectomy and a procedure to prevent vaginal shortening (101), modified radical hysterectomy (79) and simple hysterectomy (7), with systematic lymphadenectomy. RESULTS: There was a significant difference in the incidence of pelvic lymphocysts between cervical cancer (4.8%) and ovarian cancer (18.8%). The postoperative incidence of lymphocyst formation in patients undergoing radical hysterectomy with the procedure to prevent vaginal shortening (5.9%) was significantly lower than in those who underwent modified radical hysterectomy (15.2%). CONCLUSION: Our procedure to prevent vaginal shortening could be effective in preventing not only the shortening of the vagina but also the occurrence of pelvic lymphocysts in patients undergoing radical hysterectomy with systematic lymphadenectomy for gynecological malignancies.

Adolescent↗
PubMed2000

Relationship between cyclooxygenase-2 expression and K-ras gene mutation in colorectal adenomas.

BACKGROUND AND AIMS: Cyclooxygenase (COX)-2 has a trophic effect on gastrointestinal epithelial cells and is associated with the progression of colorectal adenomas. Mutation of the K-ras gene is also associated with the progression of colorectal adenomas and has recently been suggested to play an important role in the induction of COX-2. In the present study, we investigated the relationship between COX-2 expression and K-ras mutation in colorectal adenomas. METHODS: Twenty-nine colorectal adenomas were obtained from specimens resected by the use of surgery or endoscopic mucosal resection and analyzed clinicopathologically. Immunohistochemistry was performed to analyze COX-2 expression in the adenoma specimens. The K-ras codon 12 mutations were detected by using the polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: An increase of COX-2-positive cells in adenoma was observed in 11 (37.9%) lesions, 10 (90.9%) of which had a K-ras gene mutation, suggesting a significant correlation between COX-2 expression and K-ras gene mutation in colorectal adenomas. Morphologically, COX-2-positive adenomas (13.8 +/- 2.6 mm) were significantly larger than COX-2-negative ones (5.8 +/- 0.9 mm). In addition, the increase of COX-2-positive cells in the lesion was observed more frequently in tubulovillous (63.6%) than in tubular (36.4%) adenoma. CONCLUSIONS: Cycloxygenase-2 expression in colorectal adenoma cells is strongly correlated with K-ras gene mutation, suggesting that COX-2 and mutated K-ras are connectively associated with the progression of colorectal adenoma.

Adenoma↗
PubMed1999

Isolation, identification and determination of a magenta subsidiary colour in food blue no. 1 (brilliant blue FCF).

A magenta subsidiary colour was isolated from commercial Food Blue No. 1 (B-1; Brilliant Blue FCF). The absorption maximum for this subsidiary colour at 580 nm is outside of the range of 614-628 nm found for other subsidiary colours and m,m-B-1. On the basis of MS and NMR analyses, the structure of the subsidiary colour was elucidated as the disodium salt of 2-[[4-[N-ethyl-N-(3-sulphophenylmethyl)amino]phenyl][4-oxo- 2,5-cyclohexadienylidene]methyl]benzenesulphonic acid. HPLC analyses revealed that 24 batches of commercial Food Blue No. 1 (three manufacturers) contain 0.1-0.8% (average: 0.5%) of the magenta subsidiary colour.

Benzenesulfonates↗