Biomedical subjects

T Hama

Publications and source records attributed to T Hama.

At least 37 records · Page 2Linked to original sources

PubMed1995

Purification and properties of beta-citryl-L-glutamate-hydrolysing enzyme from rat testis particulate.

beta-Citryl-L-glutamate-hydrolysing enzyme (beta-CGHE) was purified from rat testis particulate fraction 13,000-fold, at a yield of 7%. The enzyme was purified by ammonium sulfate fractionation, hydroxyapatite, chelating Sepharose, beta-CG-Sepharose affinity chromatography and Sephacryl S-300 gel filtration. The purified enzyme usually migrated as two periodic acid Schiff's-stained bands on native polyacrylamide gel-electrophoresis (PAGE) with molecular weights of 350 and 420 kDa. Both bands hydrolyzed beta-citryl-L-glutamate (beta-CG) to citrate and glutamate. The 420 kDa band was changed by digestion with N-glycosidase F, into a 350 kDa band on native PAGE. The purified enzyme was composed of 90, 100, 115 and 130 kDa subunits on SDS-PAGE under non-reduced conditions. The purified enzyme was pharmacologically similar to the beta-CGHE activity partially purified from rat testis. This enzyme required manganese ions for full activity and it was strongly inhibited by nucleotides such as ATP or GTP and phosphate ions. beta-CGHE was also potently inhibited by an excitatory amino acid agonist, L-quisqualate, but not by another agonists, N-methyl-D-aspartate and kinate. It had high substrate specificity for beta-CG. The antibodies against the purified enzyme reacted mainly to the 115 kDa band on the SDS-PAGE and precipitated the enzyme activity from the crude and purified enzyme solution.

Amidohydrolases↗

PubMed1995

Presence of beta-citryl-L-glutamic acid in the lens: its possible role in the differentiation of lens epithelial cells into fiber cells.

The beta-CG concentration in the chicken brain was high during embryonic development and decreased rapidly to a lower level close to hatching, while the concentration in the eyeball which was also high during the embryonic life retained a fairly high level after hatching. The distribution of beta-CG in the bovine eye was determined. About 95% of total beta-CG content in the whole eye was localized in the lens. However, the distribution of beta-CG in the eye varied depending on species. beta-CG was exclusively localized in the lens in the eyes of fish and mammals, but distributed in both lens and retina in frogs. The molecule was localized in the retina rather than the lens in the chicken eye, although the concentrations was extremely low compared to those in the mammalian, amphibian and fish eyes. It was found that beta-CG is present ubiquitously in the lens or retina in various species. The distribution of beta-CG in the bovine lens was determined in the three cortex regions and nucleus. beta-CG was present at the highest concentration in the equatorial cortex, at a moderate concentration in the posterior and anterior cortex, and at the lowest concentration in the nucleus. Similar distribution patterns were also found in the rabbit and rat lens. When embryonic chick lens epithelial cells were cultured in the presence of fetal calf serum, the cells elongated, differentiated into fiber cells and formed lentoid bodies. The cells of lentoid bodies were stained strongly by the anti-beta-CG antibody, while cells around the structures were not. In addition, the beta-CG content in the lenses from the galactose cataractous rat decreased to about 20-30% of that in the normal lens. These findings suggest that beta-CG may play a role in the differentiation of epithelial cells into fiber cells.

Animals↗

PubMed1995

Amino acids and peptides. XXV. Preparation of fibronectin-related peptide poly(ethylene glycol) hybrids and their inhibitory effect on experimental metastasis.

Hybrids of fibronectin-related peptides [Arg-Gly-Asp (RGD), Arg-Gly-Asp-Ser (RGDS)] and poly(ethylene glycol) (PEG) were prepared and their inhibitory effects on experimental metastasis in mice were examined. The inhibitory effect of RGD was markedly potentiated by hybrid formation with poly(ethylene glycol) #6000. As to inhibitory effect, RGD was more potent than RGDS and RGD PEG hybrids were superior to RGDS PEG hybrids. Hybrid formation with PEG #6000 was more effective than that with PEG #4000.

Amino Acid Sequence↗

PubMed1994

Adamantane as a brain-directed drug carrier for poorly absorbed drug. 2. AZT derivatives conjugated with the 1-adamantane moiety.

Five AZT (azidothymidine) prodrugs conjugated with the 1-adamantane moiety via an ester bond were synthesized to improve the transport of AZT into the central nervous system (CNS). In in vitro degradation studies with rat and human plasma, it was demonstrated that the prodrugs were degraded enzymatically and converted quantitatively to their parent drug. AZT. As assessed by octanol-buffer partitioning, the prodrugs were much more lipophilic than AZT and were expected to penetrate the blood-brain barrier (BBB) readily. In in vivo studies, in which the prodrugs were administered intravenously to rat, the prodrugs in brain tissue were detected at 7-18 times higher concentrations than AZT in spite of the negligible amount of the prodrug in the cerebrospinal fluid. These results indicate that the introduction to AZT of the 1-adamantane moiety results in the enhancement of the BBB penetration. This pharmaceutical approach would be beneficial for the efficient treatment of the CNS infection by human immunodeficiency virus.

Adamantane↗

PubMed1994

Flow cytometric analysis of mouse sperm using monoclonal anti-sperm antibody A-1.

We have previously prepared an anti-mouse sperm monoclonal antibody (A-1) which inhibited sperm penetration into the egg zona pellucida. By indirect immunofluorescence (IIF), the A-1 antibody was shown to recognize an antigen localized in the acrosomal area of sperm. This antibody bound negligibly to fresh sperm, while binding to methanol-fixed sperm was almost complete. After methanol fixation, no sperm that penetrated into the zona were immunoreactive for this antibody. In the present study we examined the localization and fate of A-1 antigen during the acrosome reaction by IIF and flow cytometry (FCM). Cauda epididymal sperm were treated with either calcium ionophore A23187 or zona solution, immunostained indirectly, and subjected to FCM. Treatment with A23187 reduced the percentage of immunoreactive sperm to 59% from the 80% obtained in the untreated sperm. The treatment also reduced the average fluorescence intensity per fluorescence-positive spermatocyte to 65 channels, while this intensity was 89 channels in the untreated sperm. A similar result was obtained from treatment with zona solution. The proportion of sperm that was immunoreactive with A-1 antibody was reduced to 55% by incubation in zona-containing media from the 80% obtained in zona-free media. On the other hand, neither A23187 nor the zona solution affected the immunoreactivity or the fluorescence intensity of caput epididymal sperm, while the A-1 antigen was present in both the immature sperm from the caput epididymis of adult mice and in the mature sperm from the cauda epididymis of the same mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗

PubMed1994

Amino acids and peptides. XX. Preparation of beta-cyclododecyl aspartate and its application to synthesis of fibronectin- and laminin-related peptides.

beta-Cyclododecyl aspartate was prepared and its application to peptide synthesis was examined. Derivatives of beta-cyclododecyl aspartate are more likely to crystallize and should be useful for peptide synthesis. The cyclododecyl ester was much stable to bases than the benzyl ester and rather more stable than the cyclohexyl ester. It was removable by HF treatment and trifluoromethanesulfonic acid treatment. beta-Cyclododecyl aspartate was used for synthesis of laminin- and fibronectin-related peptides by solid phase and liquid phase methods.

Amino Acid Sequence↗

PubMed1994

Amino acids and peptides. XXI. Laminin-related peptide analogs including poly(ethylene glycol) hybrids and their inhibitory effect on experimental metastasis.

Laminin-related peptides, Tyr-Ile-Gly-Ser-Arg analogs, were prepared and their inhibitory effects on experimental metastasis were examined. Of the amino acids in the Tyr-Ile-Gly-Ser-Arg sequence, L-Arg was very important and Ile was not essential for the inhibitory effect. To obtain a potent inhibitor of metastasis, hybrids of Tyr-Ile-Gly-Ser-Arg-Gly and 2 types of poly(ethylene glycol) were prepared. The inhibitory effects of the hybrids were more potent than that of Tyr-Ile-Gly-Ser-Arg-Gly.

Amino Acid Sequence↗

PubMed1993

Cell and tissue distribution and developmental change of neuron specific 14 kDa protein (phosphoneuroprotein 14).

In the present paper, the distribution of a neuron-specific phosphoneuroprotein 14 (PNP 14) in cell and tissue was investigated in detail by the immunoblot method using affinity-purified antibody against this protein. The immunoblot of the supernatant fractions of various tissue homogenates of rat clearly demonstrated that PNP 14 was enormously rich in the brain. The content in rat brain was as much as 0.1% of the homogenate. The immunocytochemical study showed that the protein was localized at nerve endings in the cerebellum. Existence of the protein was also confirmed in cultured neuronal cells from postnatal rat midbrain, but not in glial cells. Examination of subcellular localization of PNP 14 indicates that the protein was present in synaptic plasma membranes and synaptic supernatant fractions, but not in synaptic vesicles. During the development of rat brain, PNP 14 came into existence after birth and it's amount linearly increased to a maximum at 21-28 days after birth. The content of the protein then remained at the same level for more than 10 months. We concluded that this protein is neuron specific and supposed that it may be involved in neuronal formation and function.

Amino Acid Sequence↗

PubMed1993

Effect of a monoclonal anti-sperm antibody (A-1) on in vitro fertilization in the mouse.

We prepared four monoclonal antibodies raised against mouse spermatozoa. The ability of the hybridoma culture supernatants to inhibit in vitro mouse fertilization was determined. One of these monoclonal antibodies, termed A-1, strongly inhibits sperm penetration into zona pellucida of egg in a concentration-dependent fashion. On the other hand, even in the presence of the same concentration of A-1 antibody, sperm binding to comulus-free eggs was slightly inhibited and sperm-egg fusion was not inhibited at all. Immuno-fluorescence studies with A-1 showed that it recognizes an antigen(s) localized in the acrosome of mouse spermatozoa. In the case of unfixed sperm, the acrosome-intact sperm (i.e., sperm bound to egg zona pellucida) and unbound sperm were slightly immunostained with A-1 antibody (1.6% and 9.0%, respectively). All the full acrosome reacted sperm (i.e., sperm penetrating into the perivitelline space) were not immunoreacted. On the other hand, when sperm were fixed with methanol, approximately 80% of unbound sperm were immunoreacted with this antibody. Furthermore, almost all of zona-binding sperm were immunostained, whereas acrosome reacted, penetrating sperm were not. These data suggested that the antigen recognized by A-1 was located inside the plasma membrane of spermatozoa, and appeared on the surface of the spermatozoa during the period of penetration into egg zona pellucida. After sperm penetration into the perivitelline space this antigen must be released from the sperm.

Animals↗

PubMed1993

Effect of bredinin on early embryonic development in mice.

Bredinin, an immunosuppressive agent, had a teratogenic effect and a decreasing effect in litter size in mice and in rats. We investigated the direct effect of bredinin on the development of mouse preimplantation embryos in vitro. Bredinin strongly inhibited the first differentiation step from the morula to the blastocyst stage, whereas the steps from the two-cell embryo to the morula stage were not inhibited. At 10(-6) or 10(-5) M of bredinin, only one or none of the morula embryos developed to a blastocyst after a 48 h culture; while approximately 90% of the embryos developed to blastocysts in the absence of bredinin. To determine whether the bredinin inhibition was reversible, the morula embryos were cultured with 10(-5) M of bredinin for 48 h. The embryos were transferred to bredinin-free culture conditions, and their development was observed. The inhibitory effect of bredinin was reversible. The expansion of zona-free blastocyst was also inhibited by bredinin. When blastocyst embryos were cultured in the presence of bredinin (10(-6) M), the mean size of the embryos was reduced to half the initial size. In addition, the steps of hatching from the zona pellucida and attaching to the substratum were significantly inhibited by bredinin. Trophoblast outgrowth was completely inhibited by 10(-6) M bredinin; however, the area of trophoblast outgrowth was expanded to 18-fold the initial size after a 96 h culture in the absence of bredinin. Thus, the decrease in the number of offspring is due to the direct effect of bredinin on mice embryos.

Animals↗

PubMed1993

Evidence for serum factors modulating antibody production in normal and macular mice.

The macular mutant mouse is a model of Menkes' kinky hair disease, which is characterized by a deficiency of ceruloplasmin in the serum. In hemizygotic mice (ml/y), the antibody production against sheep red blood cells (SRBC) was decreased. Treatment with normal (+/y) mouse serum increased in a dose-dependent manner the antibody response of ml/y mouse spleen cells in vitro. However, +/y mouse serum had no effect on +/y mouse spleen cells, even at high doses up to 5%. In contrast, ml/y mouse serum decreased antibody production in +/y mouse spleen cells in a dose-dependent manner. Antibody production in +/y mouse spleen cells decreased with time, after pretreatment with ml/y mouse serum. However, serum from ml/y mice injected with ceruloplasmin did not decrease antibody production in +/y mouse spleen cells but rather increased it in ml/y mouse spleen cells. Ceruloplasmin had no effect on the production of antibodies against SRBC in ml/y and +/y mouse spleen cells in vitro. These findings suggest that one or more enhancers of antibody production exist in normal mouse serum and that one or more suppressors of normal antibody production exist in ml/y mouse serum. It is proposed that the activities of these factors in serum may be regulated by ceruloplasmin.

Animals↗

PubMed1993

The relationship between induction of peroxisomal beta-oxidation and long-chain fatty acid composition in rat liver.

The long-chain fatty acid composition in rat liver, by which peroxisomal beta-oxidation system was induced, was analyzed in vitro and in vivo. In primary culture of hepatocytes, treatment with 0.4 mM clofibrate or long-chain fatty acids caused an increase in the peroxisomal beta-oxidation activity, in addition the oleic acid [18:1(n-9)] content in the cells was increased two-fold by addition of very long-chain fatty acids to the culture medium, but clofibrate had no effect. A two-fold of increase in 18:1(n-9) content was observed in the hepatic subcellular fractions from rats fed a diet containing 0.25% clofibric acid. The ratio of cis-vaccenic acid [18:1(n-7)] to total 18:1 content decreased by more than half compared with control in clofibric acid treated liver. The level of 18:1(n-7) was not changed in all experiments. It is suggested that perturbation of C-18 chain length fatty acids occurs in peroxisomal beta-oxidation induced liver.

Animals↗

PubMed1993

[Treatment of hemifacial spasm with botulinum toxin].

We injected botulinum toxin to treat hemifacial spasm, and investigated the effects and the patient's impression of this treatment. Average duration of improvement lasted about 3.5 months in both the initial treatment group and the recurrent group. However the patients in the recurrent group received fewer units of botulinum toxin than those in the initial treatment group. Except for local paralysis that disappeared within a month, there were very few complications. Most patient were satisfied with this treatment. We conclude that the treatment of hemifacial spasm with botulinum toxin is both simple and useful.

Adult↗

PubMed1993

The decreased immune responses in macular mouse, a model of Menkes' kinky hair disease.

The macular mutant mouse is a murine model of the Menkes' kinky hair disease, characterized by a copper deficiency in serum. The immune response of its hemizygote (ml/y) was examined, herein. Ml/y mice which were not treated with Cu were atrophy of lymphoid tissues on day 14. However, kidney, brain, heart and lung weights were higher in ml/y mice without Cu treatment than in normal (+/y) mice. When compared to cells from +/y mice, spleen cells from ml/y mice exhibited similar proliferation-curves stimulated by Con A or LPS. Lymph node cells from ml/y mice showed a significantly decreased mixed lymphocyte reaction (MLR) response when stimulated by spleen cells from Balb/c mice. Spleen cells from ml/y mice demonstrated similar stimulation against lymph node cells from Balb/c mice. Antibody production against sheep red blood cells (SRBC) in vivo, a T cell dependent response, was suppressed in ml/y mice. By contrast, the antibody production against dinitrophenyl-ficoll, a T cell independent response was similar in +/y and ml/y. The antibody production against SRBC in vitro was also suppressed in ml/y mice. However, when the T cell-enriched fraction of ml/y mouse spleen cells was replaced by the T cell-enriched fraction of +/y mouse spleen cells, the antibody production against SRBC was recovered. The percentage of Ly-5-positive cells (B cell) from ml/y mice was greater than those from +/y mice. The percentage of Thy-1.2-positive cells (T cell) was decreased, and the decrease was most prominent with the L3/T4-positive T cell (helper T cell) subset.

Animals↗

PubMed1993

Recovery of decreased antibody production by ceruloplasmin in the macular mutant mouse.

The macular mutant mouse is a murine model of Menkes' kinky hair disease, characterized by a serum copper and ceruloplasmin deficiency. The hemizygote (ml/y) had a decreased antibody response to sheep red blood cells (SRBC). 1) In vivo; the administration of ceruloplasmin recovered antibody production in ml/y mice, but, had no effect on that of normal mice (+/y). The administration of heat treated ceruloplasmin did not increase antibody production in ml/y mice, whereas the administration of various concentrations of copper suppressed the anti-SRBC plaque-forming response in both ml/y and +/y mice. 2) in vitro; ceruloplasmin had no effect upon antibody production against SRBC in both ml/y and +/y mouse spleen cells. In contrast to ceruloplasmin, 1 microgram/ml of copper inhibited the antibody production in spleen cells from both +/y and ml/y mice as well as in vivo. These findings suggested that the decreased antibody production in ml/y mice was considered to be due the decreased ceruloplasmin.

Animals↗

PubMed1992

Interleukin-6 as a neurotrophic factor for promoting the survival of cultured catecholaminergic neurons in a chemically defined medium from fetal and postnatal rat midbrains.

Interleukin-6 (IL-6, human recombinant) promoted the survival of catecholaminergic neurons from fetal and postnatal rat midbrains as assessed by an immunohistochemical staining for tyrosine hydroxylase (TH) in culture using a chemically defined medium. The maximal dose of IL-6 for the cell survival of postnatal P15 rat mesencephalic TH-positive neurons in culture for 7 days was 50 ng/ml. The survival-promoting effects on P15 cultures were observed both in high- and low-density cultures. The survival effect of IL-6 on the cultured P15 TH-positive neurons was significant for only 4-15 days in vitro. However, the viable number of TH-positive neurons with IL-6 was less than that of the control at early points in the culture process (1-2 days in vitro). Continuous presentation of IL-6 was required for promoting survival. The optimal dose of IL-6 for the survival of fetal E16 midbrain TH-positive neurons was 5 ng/ml, and the survival promoting effect was less than that for the P15 cultures. The maximal dose of IL-6 for the survival of P2 TH-positive neurons was 5 ng/ml and that of P8 was 50 ng/ml, indicating that the response of rat mesencephalic TH-positive neurons to IL-6 changes during the first postnatal week.

Animals↗

PubMed1992

Effect of bredinin on the primary culture of fetal mouse cells and adult mouse lung cells.

The effects of bredinin on the primary culture of fetal mouse cells (fetal cells) and adult mouse lung cells (lung cells) were compared. Bredinin inhibited the growth of both cells, and this inhibition was found to be caused, at least in part, by the inhibition of the S phase and/or the transition from the G1 to S phase of the cell cycle. Bredinin inhibited both DNA and RNA synthesis without affecting protein synthesis. However, the inhibitory effect of bredinin differed between the two cell lines; the fetal cells were more sensitive than the lung cells, and bredinin inhibited DNA synthesis 100 times more potently in the fetal cells. The inhibition of DNA synthesis by bredinin in the fetal cells was gradually lowered by in vitro aging of the fetal cells to a level similar to that in the lung cells. There was no difference in the rate of incorporation of bredinin into the cells between the fetal cells and the lung cells. When fetal tissue was used as an enzyme source, bredinin was converted to bredinin 5'-monophosphate (BMP), but when lung tissue was used, bredinin was not converted. This is in agreement with the finding that bredinin has selective toxicity on fetuses in vivo but is hardly toxic to adult cells, which suggests the involvement of BMP in the selective toxicity of bredinin on the fetus.

3T3 Cells↗

PubMed1992

[Compression of the graft during the corrective surgery for scoliosis in a patient who has undergone a Rastelli's operation: a case study].

A 14 year-old male who had undergone Rastelli's operation for the tetralogy of Fallot had general anesthesia for the corrective spinal instrumentation and posterior fusion. The patient also suffered from the complication of Klippel-Feil syndrome. During the operation, right ventricular pressure gradually increased from 34 mmHg to 60 mmHg and systolic blood pressure decreased from 110 mg to 80 mmHg when the maneuver to correct spinal deformity was done. The hemodynamics returned to its former level after the maneuver was resumed. This change was presumably attributed to the fact that the external conduit was compressed by the sternum and vertebral bodies. In order to prevent this hazardous incidence, it is crucial to understand both the three-dimensional configuration of the thoracic structure and the influence of spinal correction on it. In the prone positioned patients with scoliosis, especially lordoscoliosis, compression or dysfunction of the artificial valve might occur and we have to be aware of the possibility of the compression during general anesthesia and after corrective surgery.

Adolescent↗