Biomedical subjects

M Kita

Publications and source records attributed to M Kita.

At least 127 records · Page 7Linked to original sources

PubMed1993

v-Src activates the expression of 92-kDa type IV collagenase gene through the AP-1 site and the GT box homologous to retinoblastoma control elements. A mechanism regulating gene expression independent of that by inflammatory cytokines.

The 92-kDa type IV collagenase (matrix metalloproteinase-9; MMP-9) is frequently expressed in cells showing an invasive nature during physiological and pathological processes, and the expression is strictly controlled by a variety of trans-membrane signals. Binding sites for NF-kB, Sp-1, and AP-1 are reportedly required for induction of MMP-9 gene expression by tumor necrosis factor-alpha or 12-O-tetradecanoylphorbol-13-acetate. Comparison of the sequence of the newly cloned mouse MMP-9 promoter region with our previous human isolate revealed that, in addition to the above mentioned elements, four units of GGGG(T/A)GGGG sequence (GT box) were conserved between the two species. In this study, we have demonstrated that one of the GT boxes located downstream of the AP-1 site is essential along with the AP-1 site for the activation of the promoter by v-Src but not by tumor necrosis factor-alpha or 12-O-tetradecanoylphorbol-13-acetate. Gel mobility-shift assays revealed that binding proteins for retinoblastoma control element, including Sp-1 family protein, can bind specifically to GT boxes. Thus, the v-Src signals to the AP-1 site and to the GT box homologous to retinoblastoma control element acted synergistically in transcriptional activation. These results suggest that certain v-Src-mediated signals are propagated along pathways that are independent of inflammatory cytokines.

Animals↗

PubMed1993

High-performance liquid chromatographic determination of plasma ascorbic acid in relationship to health care.

We have developed a simple reversed-phase high-performance liquid chromatographic method for determining plasma ascorbic acid level and studied the relationship between its plasma concentration and fruit and vegetable intake and plasma dopamine-beta-hydroxylase activity. The samples were pretreated by precipitating the proteins and injected onto the column. Elution with a methanol gradient in sodium phosphate buffer was carried out by monitoring the absorbance at 265 nm, and the peak corresponding to ascorbic acid was well separated from other peaks of reagents used for pretreatment and from plasma endogenous components. The proposed method correlated well with the conventional dichlorophenol-indophenol method. Mean levels of ascorbic acid in normal human plasma were 0.86 +/- 0.36 mg/dl for males (twenty subjects, 19-28 years old) and 1.01 +/- 0.30 mg/dl for females (twenty subjects, 19-21 years old). There was good correlation between plasma ascorbic acid levels and dopamine-beta-hydroxylase levels, reflecting activities of daily living, but no correlation was found between these levels and dietary consumption of vegetables or fruits.

2,6-Dichloroindophenol↗

PubMed1993

Hypoxanthine phosphoribosyltransferase activity in bovine embryos during the early embryonic development.

The activity of hypoxanthine phosphoribosyltransferase (HPRT) was determined in the bovine embryo during early embryonic development. Microassay, using [(3)H] hypoxanthine, was improved to measure enzyme activity in the embryonic extract. This activity depended on the reaction time and the concentration of phosphorybosyl pyrophosphate (PRPP) in a reaction. mixture. Maximum activity was obtained at 4 hours of reaction time and at a concentration of 1 mM PRPP, but was much lower than the activity recorded in the mouse embryo. During early embryonic development, HPRT activity rapidly increased beyond the 8-cell stage. When distributions and activities of HPRT, adenine phosphorybosyltransferase (APRT), and the ratio of HPRT: APRT were examined in individual blastocysts, HPRT activity was broadly distributed, but it did not clearly show the bimodal distribution expected. Six of demi-embryos with high or low HPRT:APRT ratios were transferred to recipient cows from which 2 calves were obtained. Both offspring were of the sex predicted by the HPRT: APRT ratio. These results indicate that HPRT activity of bovine preimplantation embryos can be microassayed using radiolabeled hypoxanthine, and this assay could provide an alternative method for embryo sexing.

Journal Article↗

PubMed1993

Local immunosuppressive therapy with monoclonal anti-T cell antibody on renal allograft survival in the rat.

Considerable interest in the experimental and clinical use of MoAbs as potential therapeutic agents in allograft rejection has been generated by the recent reports of striking prolongation. In this study we investigated the efficacy of the local administration of MoAb OX-19 which is directed to the rat CD5 equivalent, through the renal artery using a rat kidney transplant model, in order to develop a potent method for modifying rejection while minimizing the systemic side effects. Untreated Lewis rats (LEW, RT-1(1)) rejected Brown-Norway rat (BN, RT-1n) kidney at 7.8 +/- 0.2 days (n = 10). Mean survival time (MST) of recipients treated with OX-19 (75 micrograms/kg per day) as single bolus injections via the dorsal penile vein for 7 days was 7.0 +/- 0.2 days (n = 5, NS). LEW hosts receiving OX-19 (75 micrograms/kg per day) continuously for 7 days via a femoral vein by using an osmotic minipump (IV-treated group) showed a slight prolongation of graft survival (MST = 8.8 +/- 0.9 days, n = 5), but this was not statistically significant. On the other hand, local continuous intrarenal arterial infusion of OX-19 (75 micrograms/kg per day) for 7 days (RA-treated group) significantly prolonged the graft survivals (MST = 16.8 +/- 1.3 days, n = 8, P < 0.01). Histological examination of MoAb-treated LEW hosts on day 6 post-grafting revealed that kidney grafts from RA-treated hosts showed a slight tubular necrosis, but reduced mononuclear cell infiltration, whereas kidney grafts from IV-treated hosts displayed a severe mononuclear cell infiltration around the artery with interstitial oedema. Moreover, the local intrarenal administration of OX-19, even when the dose is delayed until day 4 after renal grafting, has a therapeutic effect for on-going acute allograft rejection (MST = 11.4 +/- 0.8 days, n = 8) compared with administration of OX-19 intravenously from day 4 after grafting (MST = 7.6 +/- 0.2 days, n = 5, P < 0.01) or with no treatment (MST = 7.8 +/- 0.2 days, P < 0.01). The phenotype of graft infiltrating cells (GIC) was investigated on day 6 post-grafting. There was a significantly lower percentage of cells positive for OX-19, OX-8, OX-26 (transferrin receptor), and OX-39 (IL-2 receptor) in the RA group than in the IV group.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1993

[Expression of cytokine messenger RNA in mice in physiological conditions].

The expression of the cytokine genes was studied under physiological conditions in normal adult mice using RT-PCR method capable of detecting low levels of mRNA. Total RNA was prepared from brain, spinal cord, lung, spleen, liver and kidney of 6 to 8 week-old specific pathogen-free BALB/c mice 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 and IFN-gamma by PCR method. Although IL-1 mRNA was detected in all the organs, IL-3 mRNA was not detected in any organs tested. IL-2 or IL-4 mRNA and IL-5 mRNA were produced only in spleen and lung, respectively. However, IL-6, TNF-alpha and IFN mRNA were detected in some different organs. These results suggest that many kinds of cytokine mRNA were produced in vivo under physiological conditions in normal mice.

Animals↗

PubMed1993

[Induction of messenger RNA of cytokines by Herpes simplex virus infection in mice].

The induction of the cytokine mRNA after infection with Herpes simplex virus (HSV) was studied using RT-PCR method capable of detecting low levels of mRNA. Total RNA was prepared from spleen lymphocytes 3 h after infection with HSV-1 (+GC virulent variant and -GCr attenuated variant of Miyama strain) 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 and IFN-gamma by PCR method. After HSV-1 infection, IFN-alpha, IFN-beta, IFN-gamma, IL-1 beta, IL-4, IL-6 and TNF-alpha mRNA were significantly induced, but IL-2, IL-3 and IL-5 mRNA were not induced. Although IFN-alpha, IFN-gamma and IL-6 mRNA were more strongly induced by infection with +GC virulent variant than -GCr attenuated variant, there was no significant difference in the expression of other cytokine mRNA between two variants. These results demonstrate that cytokine mRNA in addition to IFN was induced by HSV infection, and suggest that cytokines as well as IFNs may play a role in the defense mechanism against HSV infection.

Animals↗

PubMed1993

[Expression of cytokine messenger RNA in murine placenta].

The expression of the cytokine genes in normal placenta was studied using RT-PCR method capable of detecting low levels of mRNA. Total RNA was prepared from placenta of specific pathogen-free BALB/c mice at the 16th day of gestation 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 and IFN-gamma by PCR method. IL-1 beta, IL-6, TNF-alpha, IFN-alpha, IFN-beta and IFN-gamma mRNA were detected in all the placentas tested. On the other hand, the expressions of IL-2, IL-3, IL-4, and IL-5 mRNA were not detected at all. These results suggest that these cytokines may play a role in the evolution of pregnancy.

Animals↗

PubMed1993

[Protooncogene c-myc amplification and cell cycle analysis in human malignant tumors].

As predictors of tumor response by radiotherapy, tumor with or without c-myc amplification and DNA histogram pattern were analyzed and evaluated for patients' prognosis. There was no relation between c-myc amplification and DNA ploidy pattern in this study. These factors also showed no relation to response rate and survival. But all of the tumors with c-myc amplification and aneuploid pattern exhibited a complete response by radiotherapy. The tumors with c-myc amplification and aneuploid pattern may be more radiosensitive than without amplification and diploid. These data suggested that c-myc amplification and ploidy pattern might be a predictive parameter before radiotherapy.

Cell Cycle↗

PubMed1993

Protection of rabbit retina from ischemic injury by superoxide dismutase and catalase.

PURPOSE: To provide evidence that free radical damage is a component of postischemic retinal injury; to determine whether antioxidant enzymes, superoxide dismutase (SOD) and catalase, can protect the retina from ischemic injury. METHODS: Total retinal ischemia for 60 or 75 min was produced in Dutch rabbits by raising intraocular pressure. Retinal recovery was monitored with the electroretinogram. Enzymes were administered as an intravenous bolus dose 2-3 min before restoration of circulation. RESULTS: In eyes subjected to 60 min ischemia, the amplitude of the a-wave 4 hours after reperfusion averaged 114.9% of baseline value in control rabbits and 126.5% in SOD-treated animals. The b-wave amplitude at this time was 79.3% and 106.8% in control rabbits and SOD-treated rabbits, respectively. After an ischemic insult of 75 min, at 4 hours the a-wave amplitude was 89.2% of baseline in control eyes, 108.8% in SOD-treated eyes, 159.6% in eyes that received a combination of SOD and catalase, and 149.8% in catalase-treated eyes. The amplitude of the b-wave was reduced to 47.8% in control eyes and 44.8% in SOD-treated eyes, but recovered to 92.3% in rabbits that received the combination therapy and 98.8% in animals that received catalase alone. CONCLUSIONS: These findings suggest that free radical generation is involved in ischemic tissue damage. The fact that antioxidant enzymes can be protective has implications for the treatment of acute ischemic diseases of the retina.

Animals↗

PubMed1992

A comparative study of development and symptoms among disintegrative psychosis and infantile autism with and without speech loss.

To investigate clinical pictures and the validity of disintegrative psychosis (DP) as defined in ICD-9, 18 cases of DP were compared with 51 and 145 cases of infantile autism (IA) with and without speech loss, respectively, on clinical variables. The DP cases showed clearer regression after more satisfactory development than the IA cases with speech loss. Around age 7, about 4 years after regression, those with DP were significantly more severely retarded than those with IA, yet both were similar in autistic symptomatology. EEG abnormalities and mothers 30 or older at delivery were significantly more common in the histories of those with DP than of those with IA. DP may be linked with IA having speech loss with regression in mental development as a common denominator.

Autistic Disorder↗

PubMed1992

A comparison of 28kHz- and 160kHz- ultrasonic aerosolization of interferon-alpha.

The efficacy and utility of interferon (IFN) in prophylaxis and treatment of nasal infections have been evaluated in recent investigation. In our basic studies on aerosolization of IFN, we examined the effect of aerosolization on IFN-alpha activity utilizing an ultrasonic inhaler (NE-U05). The effect of ultrasonic treatment (28kHz) on IFN activity was also studied. IFN activity was determined by a conventional cytopathic effect inhibition assay. Although IFN-alpha activity was partially inactivated at a specific frequency of 28kHz, it was not affected by ultrasonic treatment (160kHz) from the ultrasonic inhaler. These results show that the aerosolization of IFN-alpha by the ultrasonic inhaler can be recommended for clinical use without inactivation of IFN-alpha activity.

Administration, Intranasal↗

PubMed1992

A preliminary study on the effect of alpha-interferon treatment on the joint inflammation and serum calcium in rheumatoid arthritis.

A 12-week, double-blind controlled study comparing low dose alpha-interferon (5 x 10(5) iu, twice a week) and placebo was carried out to determine whether this drug has an immunomodulatory effect in rheumatoid arthritis. There were statistically significant improvements in the patients' joint score, C-reactive protein value and platelet count, without any side effects. Interferon-alpha caused an increase of serum calcium and a decrease of alkaline phosphatase. Thus, alpha-interferon requires further investigation as a possible additional useful treatment for rheumatoid arthritis.

Adult↗

PubMed1992

Photoperiod influences the critical caloric intake necessary to maintain reproduction among male deer mice (Peromyscus maniculatus).

The concept of critical day length is well established among rodents; reproductive function is maintained when day lengths are greater than some specific threshold. In addition to day length cues, seasonal breeding in deer mice can also be regulated by food availability. The caloric threshold necessary to support reproduction remains unspecified for seasonally breeding rodents. The present study examined the interaction between photoperiod and food availability on reproductive function in adult male deer mice (Peromyscus maniculatus). A critical caloric intake profile was constructed in long (16L:8D) and short (8L:16D) photoperiods; groups of deer mice in both photoperiods either received food ad libitum or 90, 80, or 70% of their individual ad libitum food intake for 10 wk. At autopsy, paired testes, epididymides, and seminal vesicles were removed and weighed. Body mass, total body fat, and total body water contents were also obtained. Short, as compared to long, day lengths inhibited the reproductive systems of male deer mice. However, food consumption interacted with photoperiod to affect reproductive function. Significant reductions in reproductive organ size as well as spermatogenic activity were observed among short-day mice after a 10% reduction in ad libitum food intake. Long-day animals required a 20% reduction in caloric intake to depress reproductive function. Body mass and total body water content were generally unaffected by either photoperiod or food consumption. Total body fat content was reduced in short- as compared to long-day mice. Individual reproductive responsiveness to short days increased as food availability decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Induction of cytokines in human peripheral blood mononuclear cells by mycoplasmas.

Various species of mycoplasmas were tested for their ability to induce cytokine production in human peripheral blood mononuclear cells (PBMC). Human PBMC were incubated with Mycoplasma pneumoniae, M. hyorhinis, M. arginini, M. salivarium, M. orale, M. gallisepticum or A. laidlawii for 48 hr, and the activities of interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, tumor necrosis factor-alpha (TNF-alpha) and interferon (IFN) in the supernatants were determined by ELISA or bioassay. All mycoplasma species induced IL-1 beta, IL-6 and TNF-alpha, although IL-2 was induced only by M. pneumoniae. IFN was induced by 5 of the 7 species, and the IFN produced was antigenically confirmed to be mainly IFN-alpha. On the other hand, mycoplasma-stimulated cultures did not contain detectable amounts of IFN-beta and IL-4 activities. Furthermore, the cytokines were induced by mycoplasmal contaminating cells in human PBMC as well as by mycoplasma alone. These results suggest that many kinds of cytokines induced by mycoplasma contamination in cell culture affect immunological experiments in vitro.

Biological Assay↗

PubMed1992

The influence of argon laser panretinal photocoagulation on the rabbit ERG c-wave.

We observed the influence of panretinal photocoagulation on the ERG c-wave in rabbit eyes. DC-registered ERGs were recorded from rabbit eyes before and after photocoagulation, and compared with those of the fellow eyes. The rabbits were subdivided into 3 groups according to application numbers: 500, 1000, and 1500 spots. The ERG c-waves were found to have totally disappeared in all rabbits 3 days after panretinal photocoagulation, then reappeared with various intervals. In the 500 spot group, the c-wave reappeared after one week, and almost reached control levels in one and a half months. In the 1000 spot group, a 10 day delay was noted, and 90% of control levels were regained after 6 months. In the 1500 spot group, the c-wave didn't reappear until 2 weeks later, and regained 70% (of the control level) after 6 months. The recovery rates were related to the number of laser applications. These results indicate that the ultimate degree of recovery in c-wave amplitude and the time required for the reestablishment of retinal pigment epithelium function both depend on the size of the coagulated area.

Animals↗

PubMed1992

Evidence that Lo's mycoplasma (Mycoplasma fermentans incognitus) is not a unique strain among Mycoplasma fermentans strains.

Mycoplasma fermentans incognitus has attracted much interest either as a cofactor for the progression of AIDS or as a pathogenic agent in non-AIDS-related diseases (S.-C. Lo, M. S. Dawson, P. B. Newton III, M. A. Sonoda, J. W.-K. Shih, W. F. Engler, R. Y.-H. Wang, and D. J. Wear, Am. J. Trop. Med. Hyg. 41:364-376, 1989; S.-C. Lo, M. S. Dawson, M. Wong, P. B. Newton III, M. A. Sonoda, W. F. Engler, R.Y.-H Wang, J. W.-K. Shih, H. J. Alter, and D. J. Wear, Am. J. Trop. Med. Hyg. 41:601-616, 1989; S.-C. Lo, J.W.-K. Shih, N.-Y. Yang, C.-Y. Ou, and R. Y.-H. Wang, Am. J. Trop. Med. Hyg. 40:213-226, 1989). In the present study, the genetic and serologic properties of the incognitus strain and other M. fermentans strains were compared. Furthermore, the replication of human immunodeficiency virus type 1 (HIV-1), determined by reverse transcriptase activity and HIV-1 p24 antigen level, in peripheral blood mononuclear cells was evaluated after stimulation with mycoplasma cell lysates. The psb-2.2 viruslike infectious agent DNA probe, used to identify the incognitus strain in the tissues of AIDS and non-AIDS patients by Lo et al. (Am. J. Trop. Med. Hyg. 41:364-376 and 40:213-226, 1989), showed reaction patterns similar to those of two M. fermentans strains isolated from cell cultures but not to that of the type strain PG18. Restriction enzyme patterns of the incognitus strain with EcoRI and HindIII were also similar to those of M. fermentans strains isolated from cell cultures. There were no remarkable differences in the immunoblot profiles between the incognitus strain and the other M. fermentans strains. These results suggest that the incognitus strain is not a unique strain among M. fermentans strains. Further, cell lysates of each M. fermentans strain could also enhance the replication of HIV-1 to a level similar to that of the incognitus strain as determined by the reverse transcriptase activity and the amount of the p24 antigen.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Distribution of two types of infiltrating helper T cells among rat renal allografts, spleen, peripheral blood, and regional lymph node cells.

Cytokine production by graft-infiltrating cells (GIC) of helper T cell (Th) subtypes were investigated in rat kidney allograft compared to those infiltrating the spleen, those in peripheral blood, and in regional lymph nodes. The relative proportion of OX-22 positive cells (Th type 1) and the W3/25-positive cells (Th) of GIC was 49.4 +/- 2.1% on day 3 and 52.7 +/- 2.2% on day 6, whereas those in spleen cells was 80.3 +/- 4.1% (p less than 0.05) and 95.5 +/- 2.5% (p less than 0.01), respectively. GIC produced more B cell-stimulating factor 2 (BSF-2, 106.3 +/- 8.2 U/ml) when compared to spleen cells (15.9 +/- 4.6 U/ml; p less than 0.01), peripheral blood mononuclear cells (4.2 +/- 1.0 U/ml; p less than 0.01) or lymph node cells (24.9 +/- 4.0 U/ml; p less than 0.01) upon stimulation with donor BN lymphocytes in vitro. However, GIC produced less interleukin 2 (IL-2, less than 1.0 U/ml) and IL-3 (less than 1.0 U/ml) than produced by spleen cells (5.1 +/- 0.9 U/ml, p less than 0.05, and 10.5 +/- 2.3 U/ml, p less than 0.01, respectively) or lymph node cells (4.5 +/- 0.4 U/ml, p less than 0.01; 23.5 +/- 3.1 U/ml, p less than 0.01, respectively). These results demonstrate that the subtype of Th cells which produce BSF-2 migrates selectively to allografts.

Animals↗

PubMed1992

Enhancement of the growth of human osteosarcoma cells by human interferon-gamma.

It is well known that interferons inhibit cell growth. However, we found that human interferon-gamma (HuIFN-gamma) enhanced the growth of human osteosarcoma cells, HOS-Y1 cells, in a dose-dependent manner. This enhancing effect was found only under the following conditions: when the cells were precultured for 2 or 3 days and then treated with HuIFN-gamma for 2, 3, or 4 days, and when the cells were seeded at a density of 1,000 or 2,000 cells/well. The degree of enhancement of cell growth was maximum when the cells were precultured at a density of 1,000 cells/well for 3 days and then treated with HuIFN-gamma for 2 days. The enhancing effect of HuIFN-gamma disappeared in the presence of anti-HuIFN-gamma antibody. In addition, it was found that the conditioned medium from HOS-Y1 cells enhanced the growth of HOS-Y1 cells, and that the conditioned medium from HOS-Y1 cells cultured with HuIFN-gamma enhanced the cell growth more than that from cells cultured without HuIFN-gamma. Epidermal growth factor (EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), and transforming growth factor-beta 1(TGF-beta 1) did not enhance the growth of HOS-Y1 cells. These results suggest that HuIFN-gamma enhanced the cell growth by augmenting the production of unknown growth factor(s) in HOS-Y1 cells via an autocrine mechanism.

Antibodies, Monoclonal↗