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Biomedical subjects

T Ichikawa

Publications and source records attributed to T Ichikawa.

At least 181 records · Page 10Linked to original sources
PubMed1998

Immunohistochemical changes of the transcription regulatory factors in rat striatum after methamphetamine administration.

We have found evidence for cyclic adenosine monophosphate (cAMP) response element (CRE) in the 5'-upstream region of the human 14.3.3 eta chain gene during studies on isolation and structure of animal brain 14.3.3 cDNA and the human 14.3.3 eta chain gene. cAMP response element-binding protein (CREB) and phosphorylated CREB (pCREB) may bind to this CRE. Since it was considered that these CREBs may play an important role in molecular mechanisms in the brain of animals treated with methamphetamine, we examined the express of CREB and pCREB in rat brain after acute and chronic methamphetamine administrations using antibodies against CREB and pCREB. We observed findings for change in the expression of these factors. Our findings should be discussed in relation to the data of other authors.

Animals↗
PubMed1998

The inhibitory effect of vitamin E on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis in mice based on the regulation of polyamine metabolism.

The present study was carried out in order to estimate a usefulness of vitamin E against 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in mice. Feeding high doses of vitamin E suppressed the NNK-induced elevation of the activity of ornithine decarboxylase, a key enzyme of polyamine biosynthesis, in the lungs of mice at 4 weeks after injection. In contrast, the vitamin elevated the NNK-induced decrease of the activity of spermidine/spermine N1-acetyltransferase, a key enzyme of polyamine biodegradation. In conjugation with these events, the NNK-increased level of proliferating nuclear cell antigen as a marker of cell proliferation was suppressed by vitamin E treatment. Also, the supply of high doses of vitamin E suppressed NNK-induced lung tumorigenesis in mice. These results suggest that vitamin E inhibits the development of lung tumors in mice treated with NNK, partly due to the regulation of polyamine metabolism.

Animals↗
PubMed1998

Activity patterns of neurosecretory cells releasing pheromonotropic neuropeptides in the moth Bombyx mori.

Short- and long-term firing patterns of neurosecretory cells releasing pheromonotropic neuropeptides in the silkworm moth Bombyx mori were examined. The cells showed three types of rhythmic changes in firing activity. Bursting activities with an interval of several seconds were synchronized with rhythmic abdominal motions for calling behavior. A slow fluctuation in firing activity over a period of several minutes depended on cyclic alternations of the flow of hemolymph. The electrical activity displayed a diel rhythm that related to light/dark cycles of the environment and sex pheromone titers in the pheromone gland. In addition to a transient inhibition of firing caused by a tactile or light stimulus, a long-term permanent inhibition was induced by mating with a fertile male. Thus, the insect neurosecretory system is highly coordinated with physiology and behavior in Bombyx mori and is influenced by external stimuli.

Animals↗
PubMed1998

Frequent deletion and 5' CpG island methylation of the p16 gene in primary malignant lymphoma of the brain.

A total of 10 primary malignant lymphomas of the brain were examined for deletion, mutation, and 5' CpG island methylation of the p16 gene, which is a candidate tumor suppressor gene with CDK-inhibitory function. In Southern blot analysis, p16 gene deletion was suggested in nine cases, homozygously (five cases) or hemizygously (four cases). In the remaining one case, p16 gene deletion was not suggested. Although single-strand conformation polymorphism and nucleotide analyses suggested no mutations of the p16 gene in these cases, methylation analyses revealed 5' CpG island methylation in three cases, of which two were those with presumed hemizygous deletion and one was that without deletion in Southern blot analysis. Thus, p16 gene abnormality was detected in all 10 of the brain lymphomas examined, and in 8 of them, actual p16 gene inactivation was suggested by their homozygous deletion (5 cases) or 5' CpG island methylation (3 cases). These findings suggest that p16 gene abnormality and inactivation are closely related to carcinogenesis in primary malignant lymphoma of the brain. The p15 gene, another candidate tumor suppressor gene located in the vicinity of the p16 gene, to which it shows structural and functional similarity, was also presumed to be deleted similarly in most cases. Its methylation was seen in one case, the case without the methylated p16 gene.

Brain Neoplasms↗
PubMed1998

Organization of choline acetyltransferase-containing structures in the cranial nerve motor nuclei and spinal cord of the monkey.

Cholinergic structures in the cranial nerve motor nuclei and ventral and lateral horns of the spinal cord of the monkey, Macaca fuscata, were investigated immunohistochemically with a monoclonal antibody against monkey choline acetyltransferase (ChAT). ChAT-immunoreactive perikarya and dendrites were present in the oculomotor, trochlear, abducent, trigeminal motor, facial and hypoglossal nuclei, nucleus of Edinger-Westphal, nucleus ambiguus, dorsal nucleus of the vagus, lamina IX of the cervical, thoracic and lumbar spinal cords, and intermediolateral nucleus of the thoracic spinal cord. The neuropil of the trigeminal motor, facial and hypoglossal nuclei, nucleus ambiguus and lamina IX of the cervical, thoracic and lumbar spinal cords contained many ChAT-positive bouton-like structures and they were seemingly in contact with perikarya and dendrites of motoneurons, suggesting that motoneurons in these nuclei are cholinoceptive as well as cholinergic. The oculomotor, trochlear and abducent nuclei, nucleus of Edinger-Westphal, dorsal nucleus of the vagus and intermediolateral nucleus of the thoracic spinal cord contained a small number of ChAT-immunoreactive bouton-like structures, but they did not contact with perikarya and dendrites of ChAT-positive neurons. These observations suggest that the organization of the motor nuclei is complex, at least regarding the cholinoceptivity.

Abducens Nerve↗
PubMed1998

Primary brain tumors in children under age 3 years.

During the period from 1966 to 1996 the authors analyzed the clinicopathological characteristics of 46 cases of histologically verified primary brain tumors with symptomatic onset during the first 3 years of life. The patient group included 27 males and 19 females. There were 14 patients during the first year, 13 during the second year, and 19 during the third year. Supratentorial tumors (60.9%) were more common than infratentorial tumors. Histologically, neuroepithelial tumors predominated. The incidence of ependymal tumors, particularly malignant ones, and of neuronal/mixed neuronal-glial tumors was higher than in previous reports. Congenital brain tumors, those occurring within 2 months after birth, or tumors of dysplastic origin comprised 42.9% of the tumors that developed within 1 year of birth. At the onset, macrocephaly, failure to thrive, and seizures were prominent symptoms or signs in the younger patients. Focal neurological deficits and increased intracranial pressure predominated in the older patients. All but one patient underwent surgical treatment, and 17 patients received adjuvant therapy after surgery. The prognosis was mainly related to the histology of the malignancy. The outcome of medulloblastomas was poor. The quality of life of surviving patients was relatively good, 77.8% having better performance status (PS) than the Eastern Cooperative Oncology Group PS 2.

Brain Neoplasms↗
PubMed1998

The inhibitory effect of vitamin E on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced DNA injury and the fixation of the DNA injury in mouse lungs.

In order to estimate the effect of vitamin E on DNA injury and K-ras point mutation at an early stage of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone(NNK)-induced lung tumorigenesis in mice, the present study was carried out. Presupplement with vitamin E about 15 times more than control for a week significantly inhibited NNK-induced O6-methylguanine formation in the lungs of mice at 4 and 168 h after the injection. At 30 days after the NNK injection. the activation of K-ras oncogene with a 12th codon GC-->AT transition was detected in 56% of lung samples tested by mutant-allele-specific amplification. Vitamin E supplement reduced the frequency of the mutation to 30%. These results suggest that vitamin E suppresses NNK-induced DNA injury and subsequent fixation of the injury during the initiation and post-initiation phases of the lung tumorigenesis in mice.

Animals↗
PubMed1998

A tobacco homologue of the Ri-plasmid orf13 gene causes cell proliferation in carrot root discs.

The tobacco genome contains genes, called cellular rol (c-rol) genes, that are very similar in sequence to genes present in the T-DNA of the Agrobacterium rhizogenes Ri-plasmid. We have cloned two homologues (torf13-1 and torf13-2) of the Ri-plasmid orf13 gene from Nicotiana tabacum L. cv. Havana 425. The clone torf13-1 has a 594-bp open reading frame (ORF) which is similar in sequence (77-82% for DNA and 67-77% for the deduced amino acid sequence) to orf13 genes of the agropine, mikimopine, and mannopine Ri-plasmids and the N. glauca homologue Ngorf13. Southern analyses showed that there are at least two torf13 genes derived from the N. tomentosiformis ancestor of tobacco, strongly suggesting that torf13 resulted from an ancient transfer between ancestors of modern A. rhizogenes and tobacco. Steady-state expression of torf13 mRNA is high in sepals, petals, shoot tips and in younger leaves, but considerably lower in stem tissues, lower leaves and roots. Treatment of cultured leaf discs for 5-20 days on medium containing auxin (10.7 microM alpha-naphthaleneacetic acid) and cytokinin (1.4 microM kinetin) resulted in a marked down-regulation of torf13 mRNA accumulation. Therefore, torf13 is transcriptionally active in normal tobacco tissues and the steady-state mRNA level is regulated. Inoculation of carrot-root discs with A. tumefaciens strains carrying the mannopine Ri-plasmid orf13 and torf13-1 regulated by the strong cauliflower mosaic virus 35S RNA promoter induced the formation of dense green callus on the disc surface. These findings indicate that at least one function of the orf13 ORF is conserved in the tobacco homologue, and provide direct evidence that a c-rol gene can influence cell proliferation.

Amino Acid Sequence↗
PubMed1998

A combination of preductal aortic coarctation and type B dissection: report of a case.

We present herein the case of a 39-year-old man found to have significant coarctation of the preductal aorta combined with a type B dissection, associated with Marfan's syndrome. This extremely rare pathological combination could be defined preoperatively only by a three-dimensional computed tomography scan. By means of selective cerebral perfusion, the coarctation was resected, and the total aortic arch was replaced with a Dacron graft.

Adult↗
PubMed1998

Lafutidine-induced stimulation of mucin biosynthesis mediated by nitric oxide is limited to the surface mucous cells of rat gastric oxyntic mucosa.

Although the new histamine H2 receptor antagonist, lafutidine (FRG-8813), N-[4-[4-(piperidinylmethyl)pyridyl-2-oxy]-(Z)-2-butenyl]-2-(fur furylsulfinyl)acetamide accelerates mucin metabolism of rat gastric mucosa, the physiological mechanisms by which this drug stimulates the biosynthesis remain unclear. In this paper, we report the effect of lafutidine on mucin biosynthesis in distinct sites and layers of rat gastric mucosa, including the possible participation of nitric oxide (NO). Lafutidine enhanced [3H]glucosamine incorporation into the mucin in the full thickness corpus mucosa, but not in the antrum. This stimulation on mucin biosynthesis disappeared by the removal treatment of surface mucosal cells. The lafutidine-induced increase of [3H]-labeled mucin in the corpus was completely blocked by either NG-nitro-L-arginine (10[-5] M) or 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazolne-1-oxyl-3-oxide (10[-5] M). The inhibitory action of NG-nitro-L-arginine was totally reversed by L-arginine (5 x 10[-3] M). These results suggest that the lafutidine-induced stimulation of mucin biosynthesis mediated by NO is limited to the surface mucous cells of rat gastric oxyntic mucosa.

Acetamides↗
PubMed1998

Serum and antral gastrin levels in fed and fasted rats: relation to aging.

The effect of short fasting for up to 24 h on serum and antral gastrin concentrations and G cell ultrastructure has been examined in the young rat compared with the middle-aged rat. The serum gastrin levels at 24-h fasting were markedly reduced in both young and middle-aged rats. There was also a significant decrease in antral gastrin concentrations after 24 h of fasting in the middle-aged rats. By contrast, the antral gastrin concentrations in the young rats increased progressively and significantly with fasting for up to 24 h. These responses were associated with a significant increase in the content of secretory granules of G cell, which was at its greatest by 24 h. The antral gastrin level in the 48-h fasting rats was markedly reduced to a level below that for the prestarvation group. By 48 h of starvation, the amount of secretory granules in G cell was significantly reduced (P < 0.05) compared with the 24-h fasting group. These results indicate that the effects of fasting on the antral gastrin levels in young rats differ from those of the middle-aged and that starvation for up to 24 h caused a significant increase in the antral gastrin content in the young rats' stomach.

Aging↗
PubMed1998

Moesin and CD44 expression in cutaneous melanocytic tumours.

The ERM (ezrin, radixin and moesin) family members, located just beneath the plasma membranes, are thought to be involved in the association of action filaments with the plasma membrane. One of the family members, moesin, is reported to bind to CD44. Splice variants of CD44 are thought to be associated with tumour progression or differentiation. Our aim was to investigate immunohistochemically the expression of moesin together with CD44 on paraffin tissue sections of a series of melanocytic tumours. The material included 12 ordinary melanocytic naevi, six Spitz naevi, eight dysplastic naevi, six blue naevi, seven malignant melanomas in situ, 15 primary malignant melanomas, five metastatic melanomas to the skin and five lymph node metastases. In the normal skin and the melanocytic tumours the expression of moesin was largely similar to that of CD44 standard. Strong moesin staining was observed in benign melanocytic lesions and melanomas in situ. However, the expression was decreased in advanced malignant melanomas. The moesin labelling in melanoma cells was downregulated with the depth of dermal invasion. The immunoreactivity was also diminished in the skin metastases and the lymph node metastases of melanoma. These results suggest that in melanocytic tumours, the alternation in the expression of moesin may be involved in the progression of malignancy.

Adult↗
PubMed1998

In vitro adherence of Streptococcus constellatus to dense hydroxyapatite and titanium.

Bacterial adherence to dense hydroxyapatite (HA) and titanium (Ti) rods was examined in vitro using Streptococcus constellatus ATCC27832. Streptoccus constellatus is associated with dental abscess and was isolated from the peri-implantitis. The dense HA was etched with 5% hydrofluoric acid for 0, 10, 20, 30, 40, and 50 s Adherence to the untreated dense HA was twice as high as the adherence to the Ti. The adherence to saliva-treated Ti was 13% higher than that to untreated Ti. The adherence was increased by acid-treatment of the dense HA, following a sigmoid curve from 20 to 50 s of treatment time. The dense HA has the capacity to receive more bacterial adherence than Ti and furthermore, the etched dense HA becomes more adherent.

Abscess↗
PubMed1998

Mental health of visually and hearing impaired students from the viewpoint of the University Personality Inventory.

Tsukuba College of Technology is the first national university established as an institute of higher education for the visually and hearing impaired. We have been systematically conducting a University Personality Inventory (UPI) survey on our students since 1989 to understand their mental health. In this study, we compared the UPI scores of the new students of Tsukuba College of Technology in 1993 and 1994 with unimpaired students from the University of Tsukuba (control group), but found no significant difference in the UPI scores of the visually impaired and the control group. However, we noticed a significant difference in the average UPI scores between the hearing impaired and the control group. The visually impaired group were divided into four subgroups, UPI scores descended in order from degree 1 (total blindness), to degrees 2 and 3 (amblyopia), to degree 4 (visual acuity > or = 0.3). The UPI scores of the degree 4 subgroup were significantly lower than those of the control group. An investigation of the items for which the check rate was at least 50% showed that the visually impaired students had a variety of psychological problems, most of which seemed to concern depression or anxiety as did the normal control group. The number of affirmative responses increased with low visual acuity. The only one belonging to the 'lie' scale item was observed in the group of hearing impaired students. Thus, comparing these three groups from the viewpoint of mental health, we noticed the hearing impaired group was slightly different from the other two groups, but the visually impaired group was similar to the normal control group.

Adolescent↗
PubMed1998

Urodynamic changes after endoscopic correction of vesicoureteral reflux.

Massive bilateral vesicoureteral reflux (VUR) in a 7-year-old girl with spinal scoliosis was successfully treated by endoscopic correction. She was admitted due to a febrile urinary tract infection and urinary incontinence. A cystometrogram demonstrated normal detrusor function during storage. The endoscopic subureteric injection of polytetrafluoroethylene (Teflon) was performed, resulting in the disappearance of the VUR. A postoperative cystometrogram demonstrated overactive detrusor function during storage, necessitating anticholinergic medication. She has been free of febrile urinary tract infections and incontinence for 2 years postoperatively, although self-catheterization is necessary. In a case of neurogenic vesical dysfunction with massive reflux, endoscopic subureteric injection is not only a therapeutic tool, but also a useful diagnostic option for detecting occult detrusor overactivity during storage prior to open surgery.

Child↗
PubMed1998

Expression of moesin and its associated molecule CD44 in epithelial skin tumors.

Moesin, one of the ERM (ezrin; radixin; moesin) family members, is directly associated with the cytoplasmic domain of CD44, which is now thought to be related to the metastatic potential of tumor cells. Using immunohistochemistry we investigated the expression of moesin in normal epidermis and various kinds of epithelial skin tumors: squamous cell carcinoma, verrucous carcinoma, Bowen's disease, solar keratosis, keratoacanthoma, basal cell carcinoma, and extramammary Paget's disease. Normal skin showed positive epidermal staining for moesin with the exception of the stratum corneum. The expression of moesin varied with the type of skin tumor. In basal cell carcinoma, Bowen's disease, and extramammary Paget's disease, moesin expression was either faint or negative. In contrast to Bowen's disease, invasive squamous cell carcinoma showed more intense and heterogeneous staining of the cytoplasm and the cell membrane. Verrucous carcinoma was weakly positive, with a tendency for the moesin to be distributed in the cell membrane. The staining pattern of moesin varied among the different kinds of epithelial skin tumors, and its expression was generally similar to that of the standard form of CD44. These results suggest that moesin is closely inter-related with CD44 in epithelial skin cells as seen in other cellular systems, and that the variable pattern of moesin staining among the skin tumor cells could reflect expression disorders associated with the transformation.

Carcinoma↗