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Biomedical subjects

H Hotta

Publications and source records attributed to H Hotta.

At least 127 records · Page 7Linked to original sources
PubMed1991

Activation and suppression of a cryptic promoter in the intron of the human melanoma-associated ME491 antigen gene.

A deletion mutant of the human melanoma-associated ME491 antigen gene starting at the first intron (lambda R31) differentially mediates the antigen expression depending on the cell type. Cryptic promoter activity residing in a 270-base-pair (bp) fragment of the first intron was examined by primer extension analysis and recombinant chloramphenicol acetyltransferase (CAT) assay. The cryptic promoter, further localized within a 153-bp fragment (fr153BN), exerted its effect in Ltk- and H-ras-transformed NIH3T3 (3T3-Hras) but not in parental NIH3T3 cells. The results suggested that the cryptic promoter was associated with a novel ras-responsive positive regulatory element, since fr153BN did not contain an AP-1-binding sequence motif, known as the ras-responsive enhancer element. The cryptic promoter activity of fr153BN was suppressed by an upstream 121-bp fragment (fr121SB) which contained a consensus sequence motif for binding of a repressor protein, GC factor, and regions showing sequence similarity with putative cis-acting repressor elements found in the vimentin gene. The degree of the suppression was greater in 3T3-Hras than in Ltk- cells. These positive and negative regulatory elements may be differentially involved in the regulation of ME491 antigen expression depending on the cell type.

3T3 Cells↗
PubMed1991

Age-related changes in rates of basal secretion of immunoreactive vasoactive intestinal polypeptide and dopamine into pituitary stalk blood from the hypothalamus in anesthetized male rats.

Age-related changes in prolactin (PRL) in systemic blood plasma, and in secretions of hypothalamic vasoactive intestinal polypeptide (VIP), an important candidate for PRL-releasing factor, and dopamine, a PRL-inhibiting factor, into the pituitary stalk blood were investigated. The experiments were performed on male urethane-chloralose-anesthetized Wistar rats of three different ages, i.e., (1) adult rats 5-8 months old, (2) middle-aged rats 12-15 months old, and (3) aged rats 24-26 months old. The concentration of immunoreactive PRL (iPRL) in systemic blood plasma of the aged rats was significantly higher than that of the adult rats (p less than 0.01). The secretion rate of hypothalamic immunoreactive VIP (iVIP) into the pituitary stalk blood was unchanged during aging, while that of dopamine was markedly increased in the aged rats in comparison with the value in both adult and middle-aged rats (p less than 0.01). These results indicate that the basal secretion of hypothalamic VIP is well maintained, while that of hypothalamic dopamine is augmented in aged rats with hyperprolactinemia. It can be assumed that the increase in the pituitary PRL secretion is a primary event during aging in rats, and that a high circulating level of PRL may facilitate the hypothalamic dopamine secretion through the activation of a negative feedback system of the hormone.

Aging↗
PubMed1991

Changes in basal secretion rates of thyroxine and 3,3',5-triiodothyronine from the thyroid gland during aging of the rat.

The present experiments were carried out to examine age-related changes in the basal secretion rates of both thyroxine (T4) and 3,3',5-triiodothyronine (T3) from the thyroid gland. The experiments were performed on male Wistar rats of three different ages, i.e., (1) adult rats of 6-8 months old, (2) middle-aged rats of 25-26 months old, and (3) aged rats of 28-30 months old. The rats were anesthetized with 1.0% halothane. The thyroid venous blood as well as systemic arterial blood was collected and secretion rates of both immunoreactive T4 (iT4) and T3 (iT3) from the thyroid gland were calculated from the differences in concentrations of iT4 and iT3 in these two blood plasmas, and from the flow rate of thyroid venous blood plasma. The secretion rates of thyroid iT4 in the three different age groups were as follows: 483 +/- 68 pg/min (mean +/- S.E.) in the adult rats, 598 +/- 104 pg/min in the middle-aged rats, and 491 +/- 150 pg/min in the aged rats. There were no significant differences among the secretion rates of thyroid iT4 in these rats. The secretion rates of thyroid iT3 in the groups were as follows: 36.2 +/- 7.5 pg/min in the adult rats, 58.9 +/- 13.9 pg/min in the middle-aged rats, and 61.3 +/- 7.6 pg/min in the aged rats. The secretion rates of thyroid iT3 in both middle-aged and aged rats were approximately 1.6-1.7 times as high as the value in adult rats (p less than 0.05). These results indicate that the thyroid secretion of iT4 is well maintained, while that of iT3 increases during aging.

Aging↗
PubMed1991

[Persistent primitive proatlantal intersegmental artery (PPPIA) presenting with cerebral infarction].

A case of persistent primitive proatlantal intersegmental artery (PPPIA) is reported. A 65-year-old male with treated hypertension was admitted to our clinic complaining of dysarthria and hemiparesis of sudden onset two days after the ictus. CT revealed spotty low-density lesions in the left corona radiata and bilateral thalami with bilateral watershed infarction. MRI findings were also compatible with cerebral infarction. Left common carotid angiography demonstrated a large anastomosis between the external carotid artery and the vertebral artery at the proatlantal region. Neither of the vertebral arteries were visualized on digital subtraction aortography. All the blood circulation of the vertebro-basilar system was through this anastomotic artery (PPPIA). A flow study revealed hypoperfusion in the territory of the left middle cerebral artery on 133Xe SPECT. Bone window CT of cervical vertebrae revealed hypoplasia of the left transverse foramen in C2, C3, C4, C5, C6 vertebrae. This case is very suggestive of an anaplasia or hypoplasia of the vertebral arteries. The etiology of his left frontal infarction seemed to be a blood-stealing phenomenon of long standing, from the anterior to the posterior circulation through the PPPIA.

Aged↗
PubMed1990

In vitro properties of human melanoma cells metastatic in nude mice.

We have developed a human melanoma metastasis model in nude mice. In this model, a human variant cell line (451-LU) was obtained that spontaneously metastasized in nude mice. This variant cell line was selected from the lung of a nude mouse after several in vivo passages of human melanoma WM164 cells previously isolated from a melanoma metastasis of a patient. The WM164 cells were not competent for metastasis in nude mice prior to this selection. We compared the phenotypes of the parental nonmetastatic cell line and the metastatic variant with respect to growth at clonal seeding densities in protein-free medium (growth factor independence), in vitro invasion through reconstructed basement membranes, secretion of proteolytic enzymes, expression of tumor-associated antigens, and chromosomal abnormalities. Metastatic 451-LU cells showed significantly increased growth factor independence when grown at clonal seeding densities as compared to the parental cells. In in vitro chemoinvasion assays, metastatic 451-LU cells were significantly more invasive than the parental cells. The metastatic variant secreted collagenase and tissue type plasminogen activator at levels 10- and 3-fold higher than the parental WM164 cells, respectively. Polyclonal antibodies to tissue type plasminogen activator significantly inhibited invasion through reconstructed basement membranes. In metastatic 451-LU cells, expression of nerve growth factor receptor was elevated, both at the protein and transcriptional level. Metastatic cells were aneuploid with a mode of 97 chromosomes, whereas the parental nonmetastatic cells had a mode of 52 chromosomes. Our studies suggest that metastatic melanoma cell variants selected in vivo show increased independence of exogenous growth factors when grown at clonal cell densities, enhanced invasiveness in vitro, greater secretion of proteolytic enzymes, and increased chromosome mode as compared to the nonmetastatic parental cells. The data further suggest that melanoma cells isolated from metastatic lesions and maintained in vitro have an unstable invasive phenotype but that metastatic variant cells can readily be selected.

Animals↗
PubMed1990

Responses of hypogastric nerve afferent fibers to uterine distension in estrous or metestrous rats.

The response of afferent fibers in the distal end of the cut hypogastric nerve to distension of the uterus to various pressure levels was investigated in anesthetized virgin female rats on two different days of the estrous cycle (estrus or metestrus). Whereas relatively intense levels of uterine distension produced an increase in afferent activity in a pressure-dependent manner in both stages of the estrous cycle, the minimal pressure necessary to activate the fibers was significantly less on the day of estrus. These results suggest that hypogastric nerve afferent fibers are more likely to respond to potentially damaging uterine stimuli during the time when such responsiveness would be most important for reproductive success.

Action Potentials↗
PubMed1990

Protection of mice against Sendai virus pneumonia by non-neutralizing anti-F monoclonal antibodies.

Nine monoclonal antibodies (MAbs) directed to F protein of Sendai virus were obtained and characterized for their protective ability against Sendai virus infection in mice. None of the MAbs showed hemagglutination-inhibition (HI), hemolysis-inhibition (HLI), or neutralization (NT) activities in vitro when assayed by standard methods. Some of the MAbs, however, showed complement-requiring NT (C-NT) and complement-requiring hemolysis (C-HL) activities when assayed in the presence of complement. Passive immunization experiments revealed that the MAbs with higher C-NT and C-HL activities showed protective activity against Sendai virus pneumonia in mice, and that some MAbs with IgG1 isotype having neither C-NT nor C-HL activity also showed the protective activity. Digestion of the MAbs with pepsin which split immunoglobulin molecules into F(ab')2 and Fc fragments greatly suppressed the protective activity. These results suggest that not only complement-mediated immunological responses such as immune virolysis but also antibody-dependent cellular cytotoxicity (ADCC) and/or immune phagocytosis, in which complement system is not necessarily involved, play an important role in the protection of mice from Sendai virus infection.

Animals↗
PubMed1990

Functional properties of afferent fibers supplying reproductive and other pelvic organs in pelvic nerve of female rat.

1. Electrophysiological techniques were used to characterize responses of afferent fibers in pelvic nerve of adult, virgin female rats to mechanical or chemical stimulation of internal reproductive organs and to mechanical stimulation of other pelvic organs. 2. In an in vivo barbiturate-anesthetized preparation, pelvic nerve afferent fibers responded to a wide variety of mechanical stimulation applied to restricted regions of the vaginal canal, caudal uterus (body and cervix), bladder, ureter, colon, or anus. 3. Single-fiber mechanoreceptive fields were invariably confined to a single organ. Notably, responses could be evoked not only by gentle stimulation of the unit's receptive field directly on the organ itself, but also by stimulating the field indirectly with intense stimulation through the appropriate part of a contiguous organ. This innervation feature is consistent with the separability of pelvic organ functions under innocuous conditions but their confusion under noxious ones. 4. Receptive fields on the reproductive organs extended from the caudal edge of the vagina to the uterine body (including the cervix) but were most often located in the fornix (vaginocervical junction). Most units had no or low levels of spontaneous activity. Their responses to mechanical stimuli were usually slowly or moderately adapting and time-locked to the stimulus. 5. Fibers with vaginal receptive fields (including the fornix) responded best either to vaginal distension with a balloon or, more often, to a probe moving along the internal vaginal surface in a direction toward the cervix. They were observed most frequently during the proestrus stage of the rat's estrous cycle. These fibers, therefore, seem particularly suited for relaying information about stimuli that occur during mating. 6. Fibers with receptive fields on the uterine cervix and body responded best to static pressure and were observed less frequently than those with vaginal fields, regardless of estrous stage. They were, however, sensitized by hypoxia. In addition, irritation of the uterus increased the probability of observing them. These fibers, therefore, may exert their primary function during reproductive conditions different from those of virgin rats, such as parturition. 7. Response activity of most of the mechanoreceptive afferent fibers supplying reproductive organs increased as the stimulus intensity increased into the noxious range; i.e., into a range in which the stimulus momentarily produced ischemia at the stimulus site. In addition, in an in vitro preparation, pelvic nerve fibers responded in a dose-dependent manner to injections through the uterine artery of bradykinin (BRAD) as well as to other algesic chemicals, 5-hydroxytryptamine (5-HT) and KCl.(ABSTRACT TRUNCATED AT 400 WORDS)

Adnexa Uteri↗
PubMed1990

[A clinical study on the changes in interocclusal contact caused by attrition, especially on the closely occluding area of upper molar region].

Changes caused by attrition in interocclusal contact were investigated in 11 subjects with natural dentition showing no or only slight attrition and 6 subjects with natural dentition showing moderate attrition. Interocclusal spaces in the molar region in the maximally intercuspidated position of each subject were recorded in White Silicone impression material. Light-transmittance measurements of interocclusal records were made to determine differences in interocclusal spaces. Results 1. Mean values of the most closely occluding area in the upper molar region Tooth kind I B II B I M II M Slight-attrition group 0.6 0.9 3.2 2.5 (mm2) Moderate-attrition group 7.2 11.0 30.4 26.8 (mm2) 2. Mean values of ratios between most closely occluding areas and occlusal-surface projecting areas in the upper molar region Tooth kind I B II B I M II M Slight-attrition group 1.1 1.7 3.1 2.7 (%) Moderate-attrition group 13.1 21.0 28.4 27.5 (%) Conclusions 1. Differences in interocclusal spaces between the slight- and moderate-attrition groups were apparent only in the most closely occluding areas. 2. When load on supporting tissues is proportionate to the size of the closely occluding area, the supporting load probably increases as attrition progresses, although the ratio of increasing load changes little among different kinds of teeth.

Dental Occlusion↗
PubMed1989

Transcriptional enhancement of the human gene encoding for a melanoma-associated antigen (ME491) in association with malignant transformation.

A cloned DNA fragment (lambda R31) containing the human gene for melanoma-associated ME491 antigen was transfected into mouse fibroblast cell lines and the antigen expression was studied. Our preliminary observation of higher expression of the antigen in more malignant Ltk- cells and weaker expression in less malignant NIH3T3 cells tempted us to investigate the antigen expression in Harvey(H)-ras-transformed NIH3T3 cells. It was observed that malignant transformation of the lambda R31-transfected NIH3T3 cells by H-ras oncogene enhanced the antigen expression to some extent. Northern blot analysis suggested that the enhancement occurred at the transcriptional level. Nucleotide sequence analysis of the 5'-regulatory region of the ME491 antigen gene in lambda R31 identified a number of consensus sequence motifs for binding of transcription factors such as Sp1, AP-2 and polyomavirus enhancer binding proteins 2 and 3. A consensus sequence motif for binding of AP-1, known as a ras-responsive element, was not found in that region. The significance and possible involvement of the transcription factors in the enhancement of ME491 antigen expression are discussed.

Animals↗
PubMed1989

[Optic nerve hemangioblastoma. Case report].

A solitary hemangioblastoma of the optic nerve was found in a 36-year-old male with a distinct family history of intracranial hemangioblastoma. The patient was admitted with complaints of visual loss and exophthalmos of the right eye. X-rays showed enlargement of the right optic canal. Right carotid angiography revealed a hypervascular tumor in the orbital apex, supplied by the ophthalmic artery. Computed tomography disclosed a pear-shaped, isodense mass with moderate contrast enhancement in the orbital apex. The right optic nerve was enlarged along its entire course and was involved with the apical mass. Surgery via the right frontal extradural approach disclosed a solid, vascular tumor involving the optic nerve at the apex of the orbit. Histological examination showed the tumor to be a characteristic hemangioblastoma. Over 90% of intracranial hemangioblastomas are located in the posterior fossa. Supratentorial hemangioblastomas, especially those arising in the optic nerve, are extremely rare. In addition, optic nerve hemangioblastomas are frequently familial and are associated with infratentorial hemangioblastomas, angiomatosis retinae, and cysts of the abdominal viscera.

Adult↗
PubMed1988

Molecular cloning and characterization of an antigen associated with early stages of melanoma tumor progression.

The melanoma-associated antigen ME491 is expressed strongly during the early stages of tumor progression. The ME491 gene was molecularly cloned by means of DNA-mediated gene transfer followed by screening a lambda genomic library with human repetitive Alu sequences as a probe. The cloned DNA, after transfection into mouse L-cells, generated a protein with characteristics that were indistinguishable in Western blot analysis from the ME491 antigen expressed by human melanoma cells. Repeat-free subfragments of the cloned DNA were used for further studies. By Northern blot analysis, the subfragments detected a single 1.2-kilobase mRNA in the transformants and various human melanoma cell lines. ME491 complementary DNA clones were then obtained by probing a melanoma complementary DNA library with the genomic subfragments. Nucleotide sequence analysis of the cloned complementary DNA indicated that the ME491 antigen consists of 237 amino acids (Mr 25,475) with four transmembrane regions and three putative N-glycosylation sites. No significant structural homology was observed with other proteins thus far reported. We observed that the amounts of mRNA varied greatly with different melanoma cell lines. Southern blot analysis revealed no amplification or rearrangement of the ME491 gene in the human melanoma cell lines tested, including both high and low expressors of this antigen. The ME491 gene has been mapped to chromosome region 12p12----12q13 by somatic cell hybrid analysis and more narrowly localized to 12q12----12q14 by in situ hybridization.

Amino Acid Sequence↗
PubMed1987

Changes of phospholipase A2 inhibitory activity in the K+-sensitive actin gelation factor during the differentiation of myeloid leukemia cells.

The phospholipase A2 inhibitory activity of a 38 kDa K+-sensitive actin gelation factor in a murine leukemia cell line (M1) was examined. A specific antibody against 38 kDa protein was found to cross-react with 37 kDa protein (lipocortin) in rat peritoneal exudates. Although the native 38 kDa protein from M1 cells did not block phospholipase A2 activity, pretreatment with alkaline phosphatase produced a form that did inhibit this enzyme. However, a purified 38 kDa protein from differentiated M1 cells blocked phospholipase A2 activity without pretreatment with alkaline phosphatase. Phospholipase A2 inhibitory activity of the 38 kDa protein was not altered by addition of actin. These findings suggest that the phospholipase A2 inhibitory of our 38 kDa protein was induced during differentiation. We also proposed that our 38 kDa protein has the same epitope as lipocortin.

Actins↗
PubMed1987

Interferon-beta gene regulation: tandemly repeated sequences of a synthetic 6 bp oligomer function as a virus-inducible enhancer.

Evidence is presented that virus-induced transcriptional activation of the human interferon-beta gene is mediated by repeated sequence units each consisting of 6 bp. The repeated units are present in the region between -65 and -109 relative to the cap site. We chemically synthesized the "consensus" DNA sequence units and tested their ability to confer virus inducibility on cognate and noncognate promoters. Most of such sequence units when tandemly repeated indeed mediate virus-induced activation of the promoter sequences. The most efficient sequence unit, AAGTGA, contributes incrementally in virus-induced activation of transcription and manifests properties of an inducible enhancer. Evidence is also provided that suggests that interaction of a positive regulatory factor(s) with this regulatory region.

Animals↗
PubMed1986

Degranulation and histamine release from murine mast cells sensitized with dengue virus-immune sera.

Mice were immunized with dengue type 2 virus (DEN 2) under a schedule favoring the production of IgE antibody. The antibody obtained could sensitize peritoneal resident mast cells both in vitro and in vivo so that the sensitized cells were degranulated and released histamine on challenge with the DEN 2 antigen. It was also demonstrated that the antibody was cytophilic and heat-labile. The above observations suggest that the present experimental system can be used to detect anti-DEN 2 IgE antibody in mice.

Animals↗
PubMed1986

Antibody-mediated enhancement of infection by dengue virus of the P815 murine mastocytoma cell line.

Dengue type 2 virus (DEN 2) could replicate only to a limited extent in a murine mastocytoma cell line, P815. The viral multiplication was enhanced 10- to 100-fold by mouse anti-DEN 2 antiserum or anti-DEN 2 type-specific monoclonal antibody diluted beyond their neutralizing titers. Cells incubated with virus-antibody mixtures changed morphologically, developing a mature mast cell-like appearance, 4-5 days after infection. The indirect fluorescent antibody technique showed that the enhancement of infection was caused by an increase in the number of DEN 2-infected cells. This is the first report that cells of mast cell lineage support dengue virus multiplication, and that virus production is enhanced in the presence of anti-dengue antibodies.

Animals↗
PubMed1985

Increased multiplication of dengue virus in mouse peritoneal macrophage cultures by treatment with extracts of Ascaris-Parascaris parasites.

Methylcellulose-elicited peritoneal macrophages from BALB/c mice were cultivated in vitro and inoculated with dengue virus (DV). At intervals thereafter portions of the culture fluids were taken and titrated for viral infectivity. Extracts from Ascaris suum and Parascaris equorum, either crude or Sephadex G-100 fractionated, were examined for effects on the multiplication of DV. The macrophage cultures treated with the above substances produced larger amounts of DV compared with untreated control cultures. The enhancing effect of the substances depended on doses added and duration of treatment and was suppressed by co-treatment with carrageenan, a specific macrophage-inhibiting agent, but was not related to the viability of cultured cells. In fluorescent antibody (FA) as well as infectious center assay experiments, it was shown that the DV-infected cells were found more frequently in treated cultures than in untreated control cultures. In the treated cultures phagocytosis by cultured cells was also of a higher magnitude than that in untreated cultures. In cocultures of macrophages and splenocytes from the same line of mice, no additive effect of splenocytes was noted. The limulus amebocyte lysate clotting enzyme reaction (Limulus test) indicated that involvement of bacterial lipopolysaccharides in the enhancement phenomena was negligible. The data so far obtained suggest that the enhancing effect was due to direct action of the parasitic extracts on macrophages. Four Sephadex G-100 fractions from the crude extracts showed similar activities; however, the effects of fractions I and III appeared to be comparatively strong. Significance of the findings in relation to the pathogenesis of DV infection was discussed.

Animals↗