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Biomedical subjects

K Kobayashi

Publications and source records attributed to K Kobayashi.

At least 145 records · Page 8Linked to original sources
PubMed2003

Adhesion and releasing of Poliovirus to activated sludge of wastewater purifying plants.

Pathogenic enteric viruses are released from infected persons through domestic wastewater to the environment. From that point of view, the knowledge of the viral behavior in wastewater purifying process is important: it is, however, still poorly understood. In this study, we reported the adhesion of Poliovirus to activated sludge samples taken from wastewater purifying plants by using a model system. More than 10(6) particles adhered to one gram (wet) of activated sludge, and the adhered viral particles maintained infectivity for longer period of time and showed higher thermo-resistant than the free viral particles. The adhered viral particles were released by increase of salt concentration or alkaline pH buffer as infectious particles. The data suggest that pathogenic viruses could be enriched and maintain the infectivity in the activated sludge, and released to environments under certain conditions.

Adsorption↗
PubMed2003

Reconstruction of the medial patellofemoral ligament for the treatment of habitual or recurrent dislocation of the patella in children.

We investigated the clinical outcome of a reconstructive procedure of the medial patellofemoral ligament for the treatment of habitual or recurrent dislocation of the patella in four children (6 knees), with a minimum follow-up of four years. The technique involves transfer of the tendon of semitendinosus to the patella using the posterior one-third of the femoral insertion of the medial collateral ligament as a pulley. There was no recurrence of dislocation after surgery. The mean Kujala score at follow-up was 96.3 points. Radiological assessment showed that the congruence angle, the tilt angle and the lateral shift radio were restored to normal. The lateral and medial stress shift ratios and the Insall-Salvati ratio remained abnormal. We conclude that this technique can be recommended for the treatment of habitual or recurrent patellar dislocation in children, although hypermobility and patella alta are not fully corrected.

Child↗
PubMed2003

Clinical measurement of force systems upon activation of transpalatal arch in the treatment of unilateral crossbite.

OBJECTIVES: in this study, forces and moments acting on the molars were theoretically determined by means of small-deflection analysis when an asymmetric third-order activation of the TPA was carried out. MATERIALS AND METHODS: the transpalatal arch (TPA) is used to correct unilateral crossbites through the application of buccal root torque to the anchorage molar and lingual root torque to the contralateral molar in crossbite, combined with expansion. Unfortunately, the complex force systems created at the molars upon activation of the TPA cannot be easily estimated. RESULTS: our computations revealed that the vertical forces developed on the molars when both ends of the TPA are inserted into the lingual sheaths (two-couple system) is four-times greater than those when only one end is tied to the lingual sheath as a single-point contact (one-couple system). CONCLUSIONS: we propose a method of clinical estimation of the force system in a two-couple system by directly measuring the vertical force produced by the one-couple system.

Algorithms↗
PubMed2003

Interindividual variation in the ratio between plasma morphine and its metabolites in cancer patients.

In 25 cancer patients treated with slow-release oral morphine and in 10 cancer patients treated with continuous infusion of morphine, plasma steady-state concentrations of morphine (M), morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) were determined by high-performance liquid chromatography. Blood samples were withdrawn at 0, 2 and 6 h after oral administration in patients treated with slow-release oral morphine and once or twice a day in patients treated with continuous infusion of morphine. In four cancer patients treated with continuous infusion of morphine, in order to analyze chronopharmacokinetic variability, the M-3-G/M ratio was observed at 12:00 h and 24:00 h. No significant changes were observed in M-3-G/M ratios and M-6-G ratios at 0, 2, and 6 h after oral administration of morphine. The M-3-G/M ratio (38.6 +/- 25.7) in the oral morphine group was significantly higher than that (15.3 +/- 12.9) in the continuous infusion group (p < 0.01). There was an approximately 10-fold interindividual variation in the M-3-G/M ratio both in the continuous infusion group and in the oral morphine group. These results suggest that the activity of UDP glucuronosyltransferase 2B7 in the intestinal metabolism of morphine may play an active part in a large interindividual variation in the ratio of metabolites to morphine. Further studies are needed to clarify this hypothesis.

Administration, Oral↗
PubMed2002

A nonspectroscopic method to determine the photolytic decomposition pathways of 3-chloro-3-alkyldiazirine: carbene, diazo and rearrangement in excited state.

C(60) acts as a mechanistic probe for the formation of carbene, diazo compound, and for the rearranged product via the excited state in the photolysis of 3-chloro-3-isopropyldiazirine and 3-chloro-3-chloromethyldiazirine. The carbene adds to C(60) to form methanofullerene, whereas the diazo compound adds to C(60) to form fulleroid. The olefin product arises as a result of the rearrangement in the excited state.

Journal Article↗
PubMed2002

Acute gliclazide administration enhances glucose and ketone body utilization in the perfused hind limb of normal and streptozotocin-diabetic rats.

Sulfonylureas are the most commonly used oral hypoglycemic agents. Their hypoglycemic actions are produced not only by stimulating insulin secretion but also by extrapancreatic mechanisms. Some groups have already demonstrated the extrapancreatic actions of sulfonylureas on carbohydrate metabolism in the liver, fat and muscle. In this study, we showed in an in situ perfused hind limb preparation of STZ-diabetic rats that gliclazide has an acute effect on ketone body and glucose utilization.

Animals↗
PubMed2002

Expression of cdc25A and cdc25B proteins in thyroid neoplasms.

Cdc25B and cdc25A phosphates are prominent stimulators of cell cycle progression and recent studies have also suggested their oncogenic roles. To elucidate the role of these proteins in thyroid neoplasms, we immunohistochemically investigated their expression, and neither protein was expressed in normal follicular cells. Cdc25B was frequently overexpressed in follicular adenoma and minimally invasive follicular carcinoma, but the incidence was significantly lower in widely invasive follicular carcinoma. Furthermore, the cdc25B expression level significantly decreased with the dedifferentiation of thyroid carcinoma. Cdc25A overexpression was observed in high incidences in all types of thyroid neoplasms. These results suggest that cdc25B and cdc25A play oncogenic roles in thyroid follicules and that cdc25B works predominantly in the early phase of the progression of thyroid carcinoma, whereas cdc25A plays a fundamental role in the development of thyroid neoplasms.

Adenoma↗
PubMed2002

Superconductivity and magnetic fluctuations in Cd(2))Re(2)O(7) via Cd nuclear magnetic resonance and re nuclear quadrupole resonance.

We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K.

Journal Article↗
PubMed2002

Caveolin-1 overexpression is an early event in the progression of papillary carcinoma of the thyroid.

Caveolin-1 is a major structural component of caveolae, which are plasma membrane microdomains implicated in the regulation of intracellular signalling pathways. Previous in vitro and in vivo studies on the function of caveolin-1 in carcinoma showed controversial results, indicating that the physiological role of caveolin-1 varies according to the origin of carcinoma. In this study, we investigated caveolin-1 expression in thyroid neoplasms by means of immunohistochemistry using a rabbit polyclonal antibody against caveolin-1. Normal follicular cells did not express caveolin-1. In papillary carcinoma, caveolin-1 expression was observed in high incidence, and especially in microcancer (less than 1.0 cm in diameter), caveolin-1 was positive in all cases except one. In undifferentiated (anaplastic) carcinoma, its incidence was significantly reduced. On the other hand, all cases of follicular carcinoma and adenoma were classified as negative for caveolin-1. These results suggest that caveolin-1 may play a role predominantly in the early phase of papillary carcinoma, whereas it has little influence on follicular tumours.

Adenoma↗
PubMed2002

Mutation in the caveolin-3 gene causes a peculiar form of distal myopathy.

The authors describe a patient with sporadic distal myopathy associated with reduced caveolin-3 in muscle fibers in which the muscle atrophy was restricted to the small muscles of the hands and feet. Gene analysis disclosed a heterozygous 80 G-->A substitution in the caveolin-3 gene that was identical to that of reported cases of elevated serum creatine kinase. This patient further demonstrated possible clinical heterogeneity of myopathies with mutations in the caveolin-3 gene.

Adolescent↗
PubMed2002

Cimetidine increases survival of colorectal cancer patients with high levels of sialyl Lewis-X and sialyl Lewis-A epitope expression on tumour cells.

Cimetidine has been shown to have beneficial effects in colorectal cancer patients. In this study, a total of 64 colorectal cancer patients who received curative operation were examined for the effects of cimetidine treatment on survival and recurrence. The cimetidine group was given 800 mg day(-1) of cimetidine orally together with 200 mg day(-1) of 5-fluorouracil, while the control group received 5-fluorouracil alone. The treatment was initiated 2 weeks after the operation and terminated after 1 year. Robust beneficial effects of cimetidine were noted: the 10-year survival rate of the cimetidine group was 84.6% whereas that of control group was 49.8% (P<0.0001). According to our previous observations that cimetidine blocked the expression of E-selectin on vascular endothelium and inhibited the adhesion of cancer cells to the endothelium, we have further stratified the patients according to the expression levels of sialyl Lewis antigens X (sL(x)) and A (sL(a)). We found that cimetidine treatment was particularly effective in patients whose tumour had higher sL(x) and sL(a) antigen levels. For example, the 10-year cumulative survival rate of the cimetidine group with higher CSLEX staining, recognizing sL(x), of tumours was 95.5%, whereas that of control group was 35.1% (P=0.0001). In contrast, in the group of patients with no or low levels CSLEX staining, cimetidine did not show significant beneficial effect (the 10-year survival rate of the cimetidine group was 70.0% and that of control group was 85.7% (P=n.s.)). These results clearly indicate that cimetidine treatment dramatically improved survival in colorectal cancer patients with tumour cells expressing high levels of sL(x) and sL(a).

Administration, Oral↗
PubMed2002

Contrast-enhanced MR angiography (enhanced 3-D fast gradient echo) for diagnosis of cerebral aneurysms.

We evaluated contrast-enhanced MRA (enhanced 3-D fast gradient echo, EFGRE3D, with spectral IR) for the identification of unruptured cerebral aneurysms. We examined 22 aneurysms from 15 patients. In its ability to identify aneurysms, contrast-enhanced MRA was superior to 3-D-time of flight (3D-TOF) MRA in 4 instances, equal in 17, and inferior in 1. Contrast-enhanced MRA demonstrated thrombus formation more clearly and accurately than did 3D-TOF MRA. Contrast-enhanced MRA was performed in less than 1 min, and was found to be a useful method for the identification of intracranial aneurysms.

Aged↗
PubMed2002

Effects of rolipram on in vivo dopamine receptor binding.

In order to clarify whether changes in brain concentrations of the second messenger cyclic AMP (cAMP) affect in vivo receptor binding in the brain, the effects of rolipram, a selective inhibitor of phosphodiesterase type 4 (PDE(4)), on dopamine receptor binding in the mouse brain were studied. Rolipram significantly decreased in vivo (3)H-SCH 23390 (dopamine D(1) selective radioligand) binding in the mouse striatum in a dose-dependent manner. In vivo saturation experiments together with the kinetic analysis of (3)H-SCH 23390 binding revealed that the apparent association rate constant (k(on)) for (3)H-SCH 23390 binding rather than the maximum number of binding sites available (B(max)) was decreased by rolipram. (3)H-N-methylspiperone (NMSP, dopamine D(2) selective radioligand) binding in the mouse striatum was also decreased by rolipram whereas no significant changes in (3)H-raclopride (dopamine D(2) selective radioligand) binding were observed. As (3)H-raclopride binding has been reported to be much more sensitive than (3)H-NMSP binding to competition by endogenous dopamine, the decreases in (3)H-SCH 23390 and (3)H-NMSP binding cannot be attributed to competitive inhibition by endogenous dopamine. These results indicate that changes in second messenger cAMP concentrations may affect the apparent bimolecular association rate constant (k(on)) of dopamine receptor binding in intact brain. This may be mediated by changes in the receptor micro-environment and altered actual free ligand concentration surrounding the receptors.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

Endocrine-disrupting effects of styrene oligomers that migrated from polystyrene containers into food.

The endocrine-disrupting effects of styrene dimers (SD: NSD-01, -08 and -09) and styrene trimers (ST: NST -01, -03 and -12), which migrated from polystyrene (PS) containers into instant food, were investigated together with styrene monomer (SM) using in vitro and in vivo assays. In the estrogen (ER) and androgen receptor (AR) binding assay, SM, SD and ST showed no binding activity at concentration of 10(-10)-10(-5) mol/l. In order to evaluate the estrogenic activity in vivo, the uterotrophic assay was conducted. When prepubertal and ovariectomized adult rats were dosed with SM, SD and ST for 3 days by subcutaneous injection, these compounds did not induce significant increase in uterine weight. Additionally, to evaluate anti-androgen activity in vivo, the Hershberger assay for anti-androgenic activity in the presence of testosterone treatment was conducted. When castrated, testosterone-treated immature male rats were dosed SM, SD and ST for 7 days by oral gavage, these compounds did not induce a decrease in the seminal vesicle, ventral prostate and levator ani plus bulbocavernosus muscle weights. To evaluate the effects on hormones other than sex hormones, the thyroid hormone receptor (TR) binding assay and rat serum prolactin (PRL) was conducted. In the TR binding assay, SM, SD and ST showed no binding activity at a concentration of 10(-5) mol/l. When ovariectomized rats were dosed with SM, SD and ST for 3 days by sc injection, the results showed there was no change in rat serum PRL. From the above these results, we concluded that SM, SD and ST exhibit no apparent estrogenic, androgenic, anti-androgenic and thyroid activity.

Animals↗
PubMed2002

Widespread activation of the brainstem preceding the recruiting rhythm in human epilepsies.

The excitability change of the brainstem was investigated before and during the conspicuous epileptic discharge in six patients with generalized convulsive seizures. The discharge consisted of a short duration of recruiting rhythm, which was considered equivalent to the seizure discharge on electroencephalogram. The excitability of the brainstem was measured with the parameters (amplitude and area) of component waves (wave-III and -V) of brainstem auditory evoked potentials. The theoretical background of the analysis is that brainstem auditory evoked potentials are 'far-field' potentials, by which they convey the information on the activity change of the brainstem even during the paroxysmal discharge within the cortex. The excitability of both the ventral (parameters of wave-III) and the dorsal brainstem (parameters of wave-V) exhibited a synchronized change (activation-inactivation). They were enhanced from -2.4+/-0.4 s, reaching the maxima before the onset of the seizure discharge, and decayed corresponding to the emergence of the recruiting rhythm. The results suggest the possibility that the widespread (ventral and dorsal) and synchronized activation of the brainstem triggers the seizure discharge in human generalized epilepsy. During the widespread activation of the brainstem, both the thalamus and the cortex probably undergo a suppressed inhibitory state through the cholinergic activation, precipitating the seizure discharge.

Acoustic Stimulation↗
PubMed2002

Type II citrullinaemia (citrin deficiency) in a neonate with hypergalactosaemia detected by mass screening.

Type II citrullinaemia (CTLN2) is an adult- or late childhood-onset liver disease characterized by a liver-specific defect in argininosuccinate synthetase protein. The enzyme abnormality is caused by deficiency of the protein citrin, which is encoded by the SLC25A 13 gene. Until now, however, few cases with SLC25A13 mutations have been reported in children with liver disease. We describe an infant who presented with neonatal hepatitis in association with hypergalactosaemia detected by neonatal mass screening. DNA analysis of SLC25A13 revealed that the patient was homozygous for a IVS11+1G>A mutation. This case suggests that SLC25A13 mutant should be suspected in neonatal patients with hypergalactosaemia of unknown cause.

Citrullinemia↗