Search PubMed⌕ Search

Biomedical subjects

T Chiba

Publications and source records attributed to T Chiba.

At least 307 records · Page 17Linked to original sources
PubMed1997

Prognosis and clinical features of intractable epilepsy: a prospective study.

Of the epileptic patients who were treated for > or = 5 years until the end of 1990 and had more than four seizures in 1990, 63 patients had been treated without interruption until the end of 1995. We analyzed their clinical courses from 1990 to 1995 prospectively. More than half the subjects were diagnosed with temporal lobe epilepsy. Twenty cases had presumed etiology, and 32 had neuropsychiatric complications. Of the subjects whose seizures were not controlled with conventional antiepileptic drugs (AED), 11 cases demonstrated significant improvement when new AED; that is, lamotrigine, vigabatrin, clobazam, topiramate, tiagabine or CGP33101 were added. However, 10 patients did not respond to new AED. Presumed etiology, neuropsychiatric complications, multiple epileptic foci in EEG and abnormalities on head CT or MRI were characteristics of the patients whose seizures were resistant to new AED.

Adult↗
PubMed1997

Bilateral chromophobe cell renal carcinoma in tuberous sclerosis complex.

We report on a patient with tuberous sclerosis complex and polycystic kidney disease who developed bilateral chromophobe cell renal carcinoma. We discuss the tuberous sclerosis complex, associated bilateral renal cell carcinoma, polycystic kidney disease and chromophobe cell renal carcinoma; a recently established subtype with a rather favorable prognosis. In a patient with tuberous sclerosis complex and multiple space-occupying lesions, a diagnosis of angiomyolipoma should be considered first but bilateral and/or multifocal renal cell carcinoma is a likely diagnosis.

Adult↗
PubMed1997

Helicobacter pylori independent chronological change in gastric acid secretion in the Japanese.

BACKGROUND: Gastric acid secretion in Japanese subjects decreases with aging. One of the possible causative mechanisms of this attenuated acid secretion is speculated to be a Helicobacter pylori induced chronic gastritis. The infection rate of this microorganism has decreased recently in Japan. AIMS: To investigate whether gastric acid secretion has altered over the past 20 years, and if so, what the influence of H pylori infection might be in the Japanese population. SUBJECTS AND METHODS: Gastric acid secretion, serum gastrin and pepsinogen I and II concentrations, and H pylori infection were determined in 110 Japanese subjects in both the 1970s and 1990s. RESULTS: Basal acid output as well as maximal acid output have greatly increased over the past 20 years, not only in individuals with H pylori infection but also in those without infection. Furthermore, subjects with H pylori infection tended to show decreased gastric acid secretion in comparison with those without infection, particularly in geriatric subjects. There was a positive correlation between gastric acid secretion and serum pepsinogen I concentrations. CONCLUSIONS: In Japan, both basal and stimulated gastric acid secretion have increased over the past 20 years; some unknown factors other than the decrease in H pylori infection may play an important role in this phenomenon.

Adult↗
PubMed1997

Cellular localization of mRNAs for prostaglandin E receptor subtypes in mouse gastrointestinal tract.

Regional and cellular distribution of mRNAs for prostaglandin E (PGE) receptor subtypes was investigated in the mouse gastrointestinal tract by in situ hybridization. Strong signals for EP1 transcripts were detected in cells of the muscularis mucosae layer, especially in the body of the stomach. Intense signals for EP3 transcripts were detected in neurons of the myenteric ganglia throughout the tract. Moderate EP3 mRNA expression was also observed in fundic gland epithelial cells, except for surface mucous cells in the stomach. Expression of EP4 mRNA was moderate in surface epithelial cells of the corpus and in glands from the surface to the base of the antrum. Strong EP4 signals were observed in the epithelium in the duodenum, jejunum, and ileum. In the ileum, signals were only observed in the upper part of the villi. However, no or weak signals for EP2 transcripts were detected. These findings suggest that PGE2 modulates various gastric or intestinal functions via at least three different PGE receptors.

Animals↗
PubMed1997

Production and activation of hepatocyte growth factor during the healing of rat gastric ulcers.

The hepatocyte growth factor has been reported to be a potent mitogen of various epithelial cells, including gastric mucosal cells. Therefore, production and activation of hepatocyte growth factor in the gastric wall were investigated to speculate on the possible role of this factor in the healing of gastric ulcer in rats. Indomethacin-induced gastric mucosal lesions and acetic acid induced ulcers were employed as models of acute gastric lesions and chronic ulcer, respectively. Immunoblot and Northern blot analyses indicate that experimentally induced gastric mucosal lesions stimulate not only the production of hepatocyte growth factor, but also the conversion to its active form. This conversion was accompanied by increased gene expression of hepatocyte growth factor activator in the stomach. In rats with acute mucosal lesions, hepatocyte growth factor activator mRNA was most abundant 6 h after induction of mucosal lesions. On the other hand, hepatocyte growth factor and hepatocyte growth factor activator mRNA levels were elevated until 15 days after the induction of chronic ulcers. In summary, it has been clarified that not only production, but also activation of hepatocyte growth factor is stimulated during gastric ulcer healing.

Animals↗
PubMed1997

Antiatherogenic effects of a novel lipoprotein lipase-enhancing agent in cholesterol-fed New Zealand white rabbits.

Following our report that administration of 4-diethoxyphosphorylmethyl-N-(4-bromo-2-cyanophenyl) benzamide (NO-1886) to rats elevated postheparin lipoprotein lipase (LPL) activity through an increase in the enzyme mass, we now investigate antiatherogenic effects of NO-1886 in cholesterol-fed New Zealand White rabbits. For 20 weeks, four groups of male rabbits received regular rabbit chow (the normal control), 0.25% cholesterol-containing chow (the control), and cholesterol chow supplemented with 0.5% and 1.0% NO-1886, respectively. Postheparin LPL activity at week 10 was raised by 30% in 0.5% of the NO-1886 group and 40% in 1.0% of the NO-1886 group compared with those in the control. The area under the curve of plasma cholesterol level was not different in three cholesterol-fed groups whereas the area under the curve of HDL cholesterol was approximately twofold greater in the two NO-1886 groups than in the control, and the area under the curve of plasma triglyceride was reduced to the level of the normal control. LPL activity was correlated with HDL cholesterol (r = .764, n = 18) and triglyceride (r = -.627, n = 18). Relative atheromatous area, aortic cholesterol, and triglyceride contents were reduced to approximately 25%, 60%, and 55%, respectively, of the control values by NO-1886 ingestion. Multiple regression analysis of LPL, HDL cholesterol, and triglyceride indicated that HDL cholesterol was the most powerful protector against aortic cholesterol accumulation, and triglyceride was the one to protect against the atheromatous area. We concluded that NO-1886 prevented the development of atherosclerosis through increasing LPL activity with a consequent increase in HDL cholesterol and a decrease in triglyceride without a significant influence of plasma cholesterol level.

Animals↗
PubMed1997

Cholesterol-mediated changes of neutral cholesterol esterase activity in macrophages. Mechanism for mobilization of cholesteryl esters in lipid droplets by HDL.

Cholesteryl esters (CE) in lipid droplets undergo a continual cycle of hydrolysis and reesterification by neutral cholesterol esterase (N-CEase) and acyl CoA:cholesterol acyltransferase (ACAT), respectively. The mechanism by which HDL mobilizes CE from lipid droplets in J774 A.1 cells was investigated, focusing on N-CEase activity. We asked whether HDL enhances the activity and, if so, what signals induce the change of the activity. An incubation of cells with HDL enhanced the decline of cholesteryl-[l-14C]-oleate in foam cells and increased N-CEase activity in the supernatant of cell homogenate in a concentration-dependent manner, whereas incubation with LDL decreased the activity. In addition, N-CEase activity was fivefold higher when cells were cultured in 10% lipoprotein-deficient serum (LPDS) medium (2 micrograms cholesterol/mL) than when cultured in 10% fetal calf serum medium (31 micrograms cholesterol/mL), suggesting that changes in N-CEase activity are mediated by cholesterol. An addition of cholesterol (0 to 30 micrograms/mL) in LPDS medium markedly inhibited N-CEase activity with a concomitant increase in cellular cholesterol concentration. This inhibitory effect of cholesterol was also observed in mouse peritoneal macrophages. In vitro addition of cholesterol did not affect N-CEase activity. Treatment of cells with HMG-CoA reductase inhibitors enhanced N-CEase activity, whereas ACAT inhibitor decreased the activity. Northern blot analysis of N-CEase mRNA showed that the expression was not altered by the presence of cholesterol in LPDS medium. These results suggest that cholesterol downregulates N-CEase activity, probably through cholesterol-dependent appearance of some factors.

Animals↗
PubMed1997

Ototoxic effect of erythromycin on cochlear potentials in the guinea pig.

The mechanism of hearing loss due to the administration of intravenous erythromycin was investigated in the albino guinea pig, and it was found for the first time that this drug causes cochlear dysfunction. The endocochlear potential (EP) and the cochlear microphonics (CM) recorded at the first cochlear turn transiently decreased when erythromycin was administered intravenously at dosages of 100 and 150 mg/kg. The averaged maximum decrease in EP was 16 mV (n = 5) and 33 mV (n = 5) for 100 and 150 mg/kg, respectively. The maximum decrease in the CM was about 25% when the EP reached its lowest value with the injection of 150 mg/kg. A complete recovery of the EP and CM ensured within 20 minutes after each erythromycin dose. The perilymphatic perfusion of 3 mmol/L of erythromycin decreased the EP and CM; however, in contrast to the intravenous administration, the decrease of the CM was nearly complete and both the EP and CM were irreversible. Hearing loss due to intravenously administered erythromycin could likely be attributle to the transient dysfunction of the stria vascularis, although concomitant dysfunction of the central auditory pathway cannot be excluded.

Animals↗
PubMed1997

Assessment of nutritional status of postoperative patients with biliary atresia.

Some patients of biliary atresia (BA) suffer from chronic hepatic dysfunction and/or persistent jaundice. The adverse effects of chronic liver disease on nutrition and growth should be considered on BA patients. We studied 45 BA patients ranging in age from 0.5 to 38 years and divided them into 2 groups. Group A contains the patients whose total bilirubin > or = 2 mg/100 ml, and Group B contains the patients whose total bilirubin < 2 mg/100 ml. We measured height, weight, triceps skin fold (TSF), midarm circumference (MAC) and midarm muscle area (MAMA). Visceral protein kinetics was evaluated on the basis of serum albumin and prealbumin levels. Caloric and protein intake was calculated by collecting intake data for 3 days. The results of this study were; 1) The mean TSF in Group A (47th percentile) was not significantly different from that in Group B (53th percentile). 2) The mean MAMA was significantly lower (p < 0.01) in Group A (16.4th percentile) than in Group B (36.7th percentile) 3) The prealbumin level was significantly lower (p < 0.001) in Group A (mean 9.9 mg/100 ml) than in Group B (mean 18.8 mg/100 ml). The authors conclude that the evaluation of MAMA and prealbumin were very useful to characterize the low metabolic status of protein in the damaged liver. And repeated nutritional assessment was necessary to evaluate liver function and provide adequate nutrition in BA patients.

Adolescent↗
PubMed1997

A functioning black adenoma of the adrenal gland.

A 53-year-old female had clinical and laboratory findings suggestive of Cushing's syndrome. In contrast to the Cushing's syndrome caused by cortical adenoma, a high level of urinary 17-ketosteroids (17-KS) was also noted. Imaging studies revealed a right adrenal tumor. Right adrenectomy was performed; the surgical specimen revealed a black adenoma consisting of compact cells with numerous pigments which seemed to be lipofuscin in nature. The present case indicates that black adenoma as well as adrenocortical carcinoma should be suspected, when patients with Cushing's syndrome show an increased level of urinary 17-KS excretion.

17-Ketosteroids↗
PubMed1997

Distribution and origin of nitric oxide synthase-containing nerve fibers in human nasal mucosa.

Human nasal mucosa was investigated by nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry. NADPH-diaphorase-positive fibers were distributed around blood vessels and seromucous glands, but none was seen in the respiratory epithelium. The pterygopalatine ganglion was then studied to determine the origin of these fibers, and many neurons were found to be labeled. These labeled neurons (86.2%) consisted of small (14.7%), medium-sized (18.4%) and large cells (53.1%). These results suggest that nitrinergic nerve fibers may originate from the pterygopalatine ganglion and that nitric oxide may play some role in the nervous control of the human nasal mucosa.

Humans↗
PubMed1997

Sonographic detection of tumor blood flow using a new contrast agent in woodchuck hepatomas.

The aim of this study was to assess the ability of perfluoropropane-filled albumin microspheres to visualize tumor blood flow in woodchuck hepatomas. Ten tumors in five woodchucks with hepatomas were imaged before and after intravenous injection (dosages of 0.01 ml/kg to 2.0 ml/kg) of an agent using color Doppler sonography and gray scale ultrasonography. Both enhanced imaging modalities demonstrated blood flow around and within all tumors. Enhanced gray scale ultrasonography demonstrated sonographic "tumor blush" in seven tumors (70%). In conclusion, tumor blood flow in woodchucks was visualized more clearly using the agent on both color Doppler and gray scale ultrasonography.

Albumins↗
PubMed1997

[Regional difference in the etiology of liver cirrhosis in Iwate].

To assess regional differences in the etiology of liver cirrhosis in Iwate, we analyzed 324 patients with liver cirrhosis treated at various hospitals. The etiology was HCV 44.8%, HBV 11.1%, HBV + HCV 4.6%, alcohol 27.5% (including heavy drinkers 17.9%), PBC 1.5% and non-B non-C 10.5% in Iwate. The incidence of alcoholic cirrhosis was higher than that in other prefectures, while that of HCV was lower. Especially in the northern area of Iwate, the rate of alcoholic cirrhosis was very high (39.1%--including heavy drinkers 21.8%) while viral cirrhosis was relatively low. Although the alcohol consumption volume in Iwate was not very high, marked alcohol consumption, especially shochu, was observed in the northern area of Iwate. The volume and kind of alcohol consumed in each area differed, and the etiology of liver cirrhosis differed regionally in Iwate. Thus, we should consider these districts and levels of alcohol consumption when treating patients with liver cirrhosis.

Female↗
PubMed1996

CGRP-immunoreactive nerve fibers projecting to lumbar facet joints through the paravertebral sympathetic trunk in rats.

We previously reported that the L5-6 facet joint is innervated from DRGs from L1 to L5 and the paravertebral sympathetic ganglia from T12 to L6 in rats. In the present study, to determine the sensory pathway from L5-6 facet joint, we placed the fluorescent carbocyanine dye, DiI, in the L5-6 facet joint, and examined the paravertebral sympathetic trunks and ganglia bilaterally. We found some DiI-labeled nerve fibers exhibiting calcitonin gene-related peptide (CGRP)-immunoreactivity, and some DiI-labeled neurons surrounded by CGRP-immunoreactive varicose fibers in the ganglia. The results suggest that a sensory pathway from the L5-6 facet joint to L1 and/or L2 DRGs is present in the paravertebral sympathetic trunk, and that sensory nerve fibers may connect with sympathetic postganglionic neurons projecting to lumbar facet joints.

Adrenergic Fibers↗
PubMed1996

Microvascular organization of sympathetic ganglia, with special reference to small intensely-fluorescent cells.

The vascular organization of sympathetic ganglia has been reviewed in relation to type II small intensely-fluorescent (SIF) cells. These cells are considered to be secretory cells forming large clusters surrounded by fenestrated capillaries. Immunohistochemical studies have revealed the existence of many kinds of peptides, in addition to catecholamines, in type II SIF cells. These transmitters are thought to enter the bloodstream, perfuse the adjacent ganglionic tissue, and modify the synaptic transmission and activity of sympathetic ganglionic neurons. Several authors reported portal-like intraganglionic microcirculation through which type II SIF cells participate in modulation of the principal ganglionic neurons. One large intraganglionic portal sinus located between SIF cells and principal ganglionic neurons was also reported in the inferior mesenteric ganglion. However, some authors claimed that transmitters could be absorbed through numerous capillary anastomoses, without any portal system in the superior cervical ganglion. It is noticed that the number, size, and partition of SIF-cell clusters are variable in different ganglia and different animal species. It is important to interpret the functional and morphological correlates of intraganglionic microcirculation based on the species and location of ganglia.

Aging↗
PubMed1996

Intracellular localization of cyclin-dependent kinase 5 (CDK5) in mouse neuron: CDK5 is located in both nucleus and cytoplasm.

Cyclin-dependent kinase 5 (CDK5) is one of the cyclin-dependent kinases, and is expressed in mature neurons. CDK5 has been postulated to be a neurofilament or tau protein kinase, because it phosphorylates neurofilaments and tau protein (microtubule-associated protein tau) in vitro. It has been reported that CDK5 was immunohistochemically detected only in axons of neurons. We here report the immunohistochemical study of CDK5 using two distinct antibodies, one recognizing the N-terminal of CDK5 and the other the C-terminal. Immunoreactivity of CDK5 was found not only in axons, but also intensively in nuclei, though not in nucleoli, of neurons in the mouse central and peripheral nervous systems. The nuclear CDK5 possibly has a physiological function distinct from the neurofilament or tau protein kinase.

Animals↗
PubMed1996

The synaptic structure of PACAP immunoreactive axons in the intermediolateral nucleus of the rat.

Immuno-electronmicroscopic studies were performed to detect the presence and features of synaptic contacts between pituitary adenylate cyclase activating polypeptide immunoreactive (PACAP-ir) axons and cholera toxin B-horseradish peroxidase labeled preganglionic sympathetic neurons (PSNs) in the intermediolateral nucleus of the rat thoracic spinal cord. PACAP-ir axon varicosities, which contained small clear and large core synaptic vesicles, were found to form asymmetric type of synaptic contacts with dendrites and infrequently with somata of labeled preganglionic neurons. The present study provides ultrastructural evidence of PACAP-ir synaptic contacts with PSNs, raising the possibility that the peptide may function as a transmitter/modulator to these neurons.

Animals↗