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Biomedical subjects

M Kita

Publications and source records attributed to M Kita.

At least 109 records · Page 6Linked to original sources
PubMed1995

Messenger RNA expression of heat shock proteins (HSPs) during ocular development.

The heat shock proteins (HSPs) are believed to act as molecular chaperones which appear to play some roles in regulation of normal protein folding and also in preventing damage to protein structures under various conditions of environmental stress. We examined the expression of the major HSP families, HSP60, 70 and 90 families and small HSP32, at the mRNA level in ocular development. Expression of HSP32, HSP60, HSP70, HSP84, HSP86 and heat shock cognate protein (HSC)70 mRNAs was examined by in situ hybridization. HSC70, HSP84, HSP86 and HSP60 mRNAs were expressed strongly in all ocular tissues during early stages 3 to 5, corresponding to embryonic day (E)11.5 to E14.5. At stages 6 to 7 (E15.5 to E18.5), the expression of these four mRNA species was decreased markedly in most ocular tissue, while in the retina strong HSC70 and HSP86 mRNA expression was still detected. HSP32 and HSP70 mRNAs were not detected at any stage. These results suggest that the expression of HSPs is developmentally regulated through ocular organogenesis, and the proteins may play some important roles in ocular development.

Animals↗
PubMed1995

Enhancement of growth of rabbit corneal endothelial cells by PDGF.

The effect of platelet-derived growth factor (PDGF) on the growth of rabbit corneal endothelial cells and the expression of PDGF receptor mRNA in these cells were examined in the present study. When rabbit corneal endothelial cells were cultured in the presence of natural PDGF, recombinant PDGF-BB, and PDGF-AA for 1, 3, and 5 days, natural PDGF and recombinant PDGF-BB enhanced the growth of the endothelial cells, but PDGF-AA did not. This growth promotion was suppressed by anti-PDGF antibody. PDGF enhanced also the incorporation of 3H-thymidine into the cells. When PDGF was combined with epidermal growth factor (EGF), the additive effect was recognized. The expression of the PDGF receptor mRNA was found in the endothelial cells by the polymerase chain reaction (PCR) method. It was concluded from these results that PDGF enhanced the growth of the corneal endothelial cells and that the PDGF receptor mRNA was expressed in these cells. These results suggest that PDGF may regulate corneal endothelial cell growth.

Animals↗
PubMed1994

Radiotherapy for superficial esophageal cancer.

PURPOSE: The results of definitive radiotherapy for superficial esophageal cancer is presented. METHODS AND MATERIALS: Twenty-one patients with superficial squamous cell carcinoma of the esophagus were treated by definitive radiotherapy with megavoltage x-rays in Tokyo Women's Medical College from 1975 to December 1990. Eight patients refused surgery and 13 patients were considered to be unsuitable for surgery due to advanced age or morbid conditions such as severe pulmonary dysfunction, myocardial infarction, liver cirrhosis, and other cancer. Radiotherapy was performed using 1.8-2.2 Gy fraction dose, 5 times a week and with a total dose of 50-76 Gy/5-7 weeks (median; 70 Gy). Three patients received intraluminal radiotherapy in addition. Combined chemotherapy was performed in four cases, and three cases received it before radiotherapy and one case after radiotherapy. RESULTS: Overall survival rate was 40.8%, and the cause-specific 5-year survival rate was 61.7%. The 5-year survival rate of the group with morbid conditions was 17.5%, but that of the group without morbid conditions was 60.6%. Seven patients developed recurrence (primary site: 3, lymph nodes: 3, lung: 1) and one patient revealed multicentric cancer of the hypopharynx with wide submucosal spread of the esophagus at 28 months after radiotherapy. No patient developed severe side effect due to radiotherapy. CONCLUSION: Definitive radiotherapy with or without chemotherapy can be applied as an alternative therapy to surgery for superficial esophageal cancer, even for the operable patients under good general condition.

Aged↗
PubMed1994

Prevalence of serum and salivary antibodies to HTLV-1 in Sjögren's syndrome.

There is accumulating evidence that human T-lymphotropic virus-1 (HTLV-1) infection contributes to the development of various inflammatory disorders. To elucidate the relation between the infection and Sjögren's syndrome, seroepidemiological and virological studies were conducted on patients with this syndrome in Nagasaki Prefecture, Japan, an area heavily endemic for HTLV-1. The HTLV-1 seroprevalence rate among the patients with Sjögren's syndrome (17/74, 23%) was significantly higher than that among blood donors (916/27,284, 3%), whereas the difference between patients with systemic lupus erythematosus and blood donors was insignificant. Moreover, among Sjögren's syndrome patients the seroprevalence was high irrespective of age, unlike that among blood donors, which rose with age. Titres of serum antibodies in the HTLV-1 seropositive patients with Sjögren's syndrome were similar to those among patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and significantly higher than those among healthy carriers. IgM class antibodies were commonly detected in the serum of patients with Sjögren's syndrome. However, unlike that in HAM/TSP patients, the viral load in peripheral-blood mononuclear cells was not necessarily high in the seropositive Sjögren syndrome group. Salivary IgA antibodies to HTLV-1 were common among seropositive patients with Sjögren's syndrome (5/7), which might be due to increased viral activity in the salivary glands. These antibodies were barely detectable in HAM/TSP patients (prevalence 1/10) or in healthy carriers (0/11). The findings strongly suggest that HTLV-1 is involved in the pathogenesis of the disease in a subset of patients with Sjögren's syndrome in endemic areas.

Adolescent↗
PubMed1994

Paracrine role of keratinocyte growth factor in rabbit corneal epithelial cell growth.

Keratinocyte growth factor (KGF), a member of the fibroblast growth factor (FGF) family, is expressed in stromal fibroblasts and acts specifically on cells of epithelial origin as a paracrine mediator. In this study, we examined KGF and KGF receptor (KGF-R) mRNA expression in rabbit corneal epithelial cells and keratocytes, using a reverse transcription polymerase chain reaction (RT-PCR) method. We also examined the effects of KGF on the proliferation of rabbit corneal cells in vitro. mRNA from cultured rabbit skin fibroblasts, conjunctival fibroblasts, corneal epithelial cells and keratocytes was first reverse-transcribed, and then amplified by PCR using primers specific for KGF and KGF-R. KGF mRNA was expressed in skin fibroblasts, conjunctival fibroblasts and keratocytes, but not in corneal epithelial cells. In contrast, KGF receptor mRNA was expressed in corneal epithelial cells, but not in skin fibroblasts, conjunctival fibroblasts or keratocytes. The results of Southern hybridization experiments of PCR products also showed that KGF mRNA was expressed in skin fibroblasts, conjunctival fibroblasts and keratocytes, whereas KGF receptor mRNA was expressed in corneal epithelial cells. Nucleotide sequencing of the PCR products revealed that their sequences were identical to the expected nucleotide sequences. Using the methylene blue method, we found that KGF enhanced the growth of cultured rabbit corneal epithelial cells, but not keratocytes, at a concentration of 0.01 to 100 ng ml-1. Furthermore, KGF also augmented 3H-thymidine incorporation into the corneal epithelial cells. These results suggest that KGF is a paracrine mediator of the proliferation of corneal epithelial cells as well as of keratinocytes in the skin.

Animals↗
PubMed1994

ADHD-related behavior among non-referred children: parents' ratings of DSM-III-R symptoms.

To identify the prevalence of ADHD symptoms among non-referred children, parents' ratings based on DSM-III-R criteria for ADHD were obtained for 1022 metropolitan children of ages 4 to 12. The prevalence rates of fourteen behavior items were markedly lower for boys of ages 10-12 than of ages 7-9, and for girls of ages 7-9 than of ages 4-6. 41.5% of the 7.7% subjects meeting ADHD criteria had been identified by their teachers as having problems symptomatic of ADHD, and one third had been reported by their parents as having conduct problems and emotional difficulties. A factor analysis revealed three factors: inattention; hyperactivity; and excessive verbal activities.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

Herpes simplex virus-induced expression of 70 kDa heat shock protein (HSP70) requires early protein synthesis but not viral DNA replication.

The major 70 kDa heat shock protein (HSP70), which is scarcely expressed in unstressed rodent cells, was apparently induced by infection with herpes simplex virus (HSV). Infection with HSV types 1 and 2 elevated HSP70 mRNA levels within 4 hr post-infection. HSP70 synthesis and accumulation increased in HSV-infected cells. Irradiation of HSV with UV-light abolished the ability to induce HSP70 mRNA. Inhibitors of viral DNA synthesis did not affect the induction of HSP70 in infected cells. Protein synthesis within 2 hr after infection was necessary for HSP70 induction.

Animals↗
PubMed1994

Poly(vinyl alcohol) hydrogels as soft contact lens material.

A new type of soft contact lens was developed from the poly(vinyl alcohol) (PVA) hydrogel prepared by a low temperature crystallization technique using a water-dimethyl sulfoxide mixed solvent. The PVA contact lens materials had a water content of 78% and a tensile strength of 50 kg/cm2, five times as strong as that of commercial poly(2-hydroxyethyl methacrylate) soft contact lens. The amount of proteins adsorbed to the PVA soft hydrogel material was half to one thirtieth of that of conventional soft contact lenses. Histological and scanning electron microscopic observation of rabbit eyes which had worn the PVA soft contact lens for 12 weeks showed no difference in corneal epithelium and cell arrangement in the corneal epithelium from the non-wearing eyes.

Adsorption↗
PubMed1994

Changes of gonadotrophin surge inhibiting/attenuating factor activity in pig follicular fluid in relation to follicle size.

The activity of GnSI/AF was measured in pig follicular fluid (pFF) from 58 individual follicles of various sizes, by bioassay using rat pituitary cells, to investigate the relationship between gonadotrophin surge inhibiting/attenuating factor (GnSI/AF) activity and follicular development. In addition, the correlation between GnSI/AF and inhibin activities and the content of sex steroids (oestradiol, progesterone and testosterone) of follicles was examined. The activity of GnSI/AF in pFF varied significantly (0.155-1.69 U microliter-1) with size of the follicle. The activities (mean +/- SEM) were intermediate and constant in follicles with diameters from 3 to 5 mm (0.583 +/- 0.080 U microliter-1, n = 24), were higher and reached the highest value in follicles with diameters between 6 and 8 mm (0.863 +/- 0.068 U microliter-1, n = 21), and were lower, reaching the lowest value in follicles with diameters of 9 and 10 mm (0.401 +/- 0.089 U microliter-1, n = 13). In contrast, inhibin activity was almost constant during the development of follicles, although individual values varied from 0.9 to 2.5 U microliters-1. For follicles with diameters of 4-8 mm, inhibin activity was 1.754 +/- 0.042 U microliters-1 (n = 39); activity was higher in the smallest follicles with diameters of 3 mm (2.063 +/- 0.015 U microliters-1, n = 6) and was lower in follicles with diameter of 9 mm, reaching the lowest value in follicles with diameter of 10 mm (1.176 +/- 0.068 U microliters-1, n = 7); inhibin activity was not significantly correlated with GnSI/AF activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Preparation of highly purified porcine theca cells.

A novel method for purifying dispersed porcine theca cells, with less than 3% granulosa cell contamination, was developed by the repeated use of mechanical and enzymatic procedures. The steroidogenic criteria used for the identification and purity evaluation of both theca and granulosa cells were also improved. Purified theca and granulosa cells from medium-sized follicles displayed steroidogenic differences when they were cultured in the presence of 10% fetal bovine serum: (1) the theca cells synthesized oestradiol (239.1 +/- 35.1 pg ml-1 per 2.5 x 10(5) cells in 40 h), but the granulosa cells did not synthesize it unless aromatizable androgens were added; (2) theca cells synthesized androstenedione (73.2 +/- 14.4 ng ml-1 per 2.5 x 10(5) cells in 40 h), but granulosa cells did not; (3) FSH did not affect progesterone production in theca cells; (4) the theca cells secreted androstenedione for up to 48 h; and (5) FSH significantly stimulated progesterone production in granulosa cells during a culture for 40 h (P < 0.05), but not during culture for 12 h. The lack of response to FSH was used as a reliable, functional indicator of the purity of porcine theca cells. However, this criterion proved not to be useful for cells cultured for 12 h; porcine FSH had no effect on the progesterone production of theca cells co-cultured for this time with as many as 20% granulosa cells. However, after co-culturing for 40 h, this criterion resulted in the detection of only 3% granulosa cell contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstenedione↗
PubMed1994

[Interferon and diseases].

Interferon (IFN) is part of the body's natural defense system. IFN production is a cellular response to the foreign constituents of microbes, tumors and antigens. The three types (alpha, beta and gamma) of IFN proteins differ both structurally and antigenically and have molecular weights ranging from 16,000-25,000 daltons. The IFN proteins induce antiviral, antimicrobial, antitumor, and immunomodulatory actions. We reviewed the recent studies on the relation between IFN and diseases concerning; 1) the IFN-alpha and -gamma producing capacity in patients with cancers, liver cirrhosis, diabetes mellitus and rheumatoid arthritis, 2) endogenous IFN in sera and exudates or extracts of local lesions obtained from patients with immunological diseases such as SLE, sarcoidosis, rheumatoid arthritis, Behçet's disease, and psoriasis, 3) deletion of IFN-alpha and -beta genes in human lymphoblastoid cells lines and leukemia, and 4) the expression of IFN and other cytokine (interleukins and TNF) mRNA in normal organs under physiological conditions. Although IFNs may play an important role in cancers and immunological diseases, it is necessary to consider the interactions between IFNs and other cytokines as IFN is one of the factors involved in the cytokine network in vivo.

Diabetes Mellitus↗
PubMed1994

[Expression of cytokines and interferon-related genes in the mouse embryo].

The expression of the cytokine and IFN-related genes was studied in mouse embryo using RT-PCR method capable of detecting low levels of mRNA. Total RNA was prepared from the days 7 embryos by acid guanidinium thiocyanate-phenol-chloroform (AGPC) method. cDNA was synthesized by M-MLV reverse transcriptase, and amplified using the specific oligonucleotide primers for IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, TNF-alpha, IFN-alpha, IFN-beta, IFN-gamma, IFN-alpha/beta receptor (IFN-alpha/beta R), IFN-gamma receptor (IFN-gamma R), interferon reguratory factor (IRF)-1, IRF-2 and 2'-5' oligoadenylate synthetase (2-5AS) by PCR method. Although the expressions of IL-1 beta, IL-4, IL-5, IL-6, TNF-alpha and IFN-gamma mRNA were detected in all the embryos tested, the expressions of IL-2, IL-3, IFN-alpha and IFN-beta mRNA were not detected at all. On the other hand, the expressions of IFN-related genes such as IFN-alpha/beta R, IFN-gamma R, IRF-1, IRF-2 and 2-5AS mRNA, were also detected. These results suggest that these cytokine may play an important role in early embryonic development.

Animals↗
PubMed1994

Expression of keratinocyte growth factor mRNA in ex vivo and in vitro specimens of human cornea and conjunctiva.

The expression of keratinocyte growth factor (KGF) messenger RNA (mRNA) was examined in both ex vivo and in vitro specimens of human skin, conjunctiva and cornea. Total cellular mRNA was extracted from human skin, conjunctiva, cornea, cultured skin fibroblasts, cultured conjunctival fibroblasts and cultured keratocytes. Oligo dT-primed complementary DNA (cDNA) was synthesized using each RNA sample as a template. Polymerase chain reaction (PCR) was used to amplify the DNA sequence of KGF using each cDNA sample as a template. PCR products were then digested with restriction enzymes in order to determine the KGF prototype. In all samples, PCR products of the expected size for KGF were detected. The resulting restriction pattern proved that these products were identical to KGF prototype I, ie, authentic KGF. In conclusion, human keratocytes and conjunctival fibroblasts express mRNA coding for KGF prototype I, ie, authentic KGF, in both ex vivo and in vitro specimens.

Adult↗
PubMed1994

[Expression of cytokine messenger RNA in human spleen].

The expression of the cytokine genes in human spleen was studied using reverse transcriptase-polymerase chain reaction (RT-PCR) method capable of detecting low levels of mRNA. Total RNA was prepared from human spleen by acid guanidinium thiocyanate-phenol-chloroform (AGPC) method. cDNA was synthesized by M-MLV RTase using oligo (dT)16 primer, and amplified using the oligonucleotide primers specific for IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, TNF-alpha, IFN-alpha, IFN-beta and IFN-gamma by PCR method. Although IL-1 beta, IL-4, IL-5, IL-6, IL-7, IL-8, TNF-alpha, IFN-alpha and IFN-gamma mRNA were detected in all the samples tested, IL-3 and IFN-beta mRNA was not detected at all. These results suggest that many kinds of cytokines may be produced constitutionally in human spleen, and its pattern of cytokine production was similar to that in mice.

Adult↗
PubMed1994

Enhancement of fibronectin-induced migration of corneal epithelial cells by cytokines.

PURPOSE: To examine the enhancing effect of cytokines on the corneal epithelial cell migration induced by fibronectin (FN). METHODS: A modified Boyden chamber method was used to detect chemotactic cell migration. Cells plated in the inner chamber were incubated with FN, cytokines, or both in the outer chamber at 37 degrees C for 24 hours. Cells that had migrated were stained and counted under a microscope. Checkerboard analysis was used to distinguish chemotaxis from chemokinesis. RESULTS: FN induced epithelial cell migration, but interleukin (IL)-1 alpha, IL-6, tumor necrosis factor (TNF)-alpha, and epidermal growth factor (EGF) alone did not. These cytokines, even at very low concentrations (0.1 to 100 pg/ml), enhanced FN-induced migration to levels about twofold those observed with FN alone. Checkerboard analysis demonstrated that EGF, but not IL-1 alpha, IL-6, or TNF-alpha, stimulated the chemokinesis of corneal epithelial cells in the presence of FN. CONCLUSION: EGF enhanced corneal epithelial cell migration by increasing chemokinesis, whereas IL-1 alpha, IL-6, and TNF-alpha enhanced this migration by increasing the FN-induced chemotactic activity, although these cytokines themselves do not have chemokinetic and chemotactic activity.

Animals↗
PubMed1994

Electroretinogram recovery in the rabbit after repetitive short-term ischemia in light and dark.

PURPOSE: To determine the time course and reproducibility of electroretinogram recovery after short-term (5- to 20-minute) retinal ischemia in the light and in the dark. METHODS: Electroretinogram recovery was measured in Dutch rabbits after 5-, 10-, or 20-minute episodes of ocular ischemia, repeated three times at 1-hour intervals. Results were compared under light- and dark-adapted conditions. RESULTS: The rate of b-wave recovery was highly reproducible after repetitive ischemic insults in the same eye. The rate of b-wave recovery varied in proportion to the duration of ischemia but generally reached 100% of preischemic levels within 45 to 60 minutes. Recovery was slower under dark-adapted conditions than under light-adapted conditions, and 10 minutes of ischemia appeared to be a critical duration to maximize light- and dark-adapted metabolic differences. CONCLUSIONS: Because of the speed and reproducibility of electroretinogram recovery, the use of short-term ischemic episodes may facilitate studies on the pharmacologic therapy of retinal ischemia. It remains to be determined, however, whether the retinal effects of short-term ischemia are mediated by the same mechanisms as the effects of longer-term ischemia.

Animals↗