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Biomedical subjects

S Hidaka

Publications and source records attributed to S Hidaka.

At least 127 records · Page 7Linked to original sources
PubMed1993

Possible regulatory roles of silicic acid, silica and clay minerals in the formation of calcium phosphate precipitates.

The effects of silicic acid, silica and clay minerals on the conversion of amorphous calcium phosphate to hydroxyapatite (HAP) were studied in vitro by a pH drop method. At a concentration range of 0.01-0.1 mM. silicic acid stimulated the rate of HAP transformation by about 30-40%. Silica stimulated the rate of HAP transformation by 33-43% at a concentration range of 0.05-1.5 mg/ml. The clay minerals, i.e. kaolin and talc, also stimulated the rate of HAP transformation by 40-90% at a concentration range of 0.4-10 mg/ml, but mica inhibited the reaction markedly at 10 mg/ml. The distribution of silicon in human supragingival dental calculus was studied by an electron-probe microanalyser. We found localized silicon distribution on the oral surface of the calculus. Such silicon-rich areas always contained silicon either alone or together with magnesium, aluminium, potassium, calcium and iron. This implies that the silicon-rich area may be opal and mica. Because silicic acid, silica, kaolin and talc stimulated and mica inhibited the in vitro calcium phosphate precipitation, it is possible that these silicon-rich areas may regulate the formation of the dental calculus.

Adult↗
PubMed1993

Intra-GBM site of the functional filtration barrier for endogenous proteins in rats.

The passage of various endogenous proteins [such as albumin, transferrin, immunoglobulin G (IgG), and immunoglobulin M (IgM)] across GBM was studied in vivo in normal Munich-Wistar rats. Glomeruli were fixed by three different methods: in situ drip-fixation, perfusion- and immersion-fixation; then they were processed for immunogold electron microscopy. The most reproducible results were obtained with in situ drip-fixation. Albumin, transferrin and IgG penetrated into GBM, but IgM did not. Morphometry revealed that density of albumin increased towards the inner 1/5 to 1/3 of GBM (junction of lamina rara interna and lamina densa) and decreased towards the subepithelial region of GBM, whereas density of IgG and transferrin was the highest at the subendothelial site and declined towards the subepithelial side of GBM. These findings suggest that central and/or outer zone of GBM constitute the main filtration barrier for albumin, and that subendothelial zone may contribute also to the charge-selective barrier. It is also suggested that the subendothelial zone acts more effectively as a filtration barrier for IgG and transferrin than for albumin. In the outer zone of GBM, which roughly corresponds to lamina rara externa visualized by conventional electron microscopy, the relative density of IgG and transferrin was higher than that of albumin. Since the pI of albumin was lower than that of IgG and transferrin, this finding suggests that subepithelial zone of GBM also acts as a charge-selective barrier. In conclusion, the main GBM filtration barrier for albumin might be the central and outer zones of GBM, and that for transferrin and IgG might be the entire width of GBM.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1993

Inhibition of the formation of oral calcium phosphate precipitates: beneficial effects of Chinese traditional (kampo) medicines.

Screening tests on the formation of calcium phosphate precipitates using 23 different kinds of Kampo medicines (Chinese traditional medicines) were carried out, at concentrations where the effects of chelation are not significant. Four of them, Hochu-ekki-to (TJ-41), Kyuki-kyogai-to (TJ-77), Oren-to (TJ-120) and Inchin-ko-to (TJ-135) showed an inhibitory effect on the formation of amorphous calcium phosphate (ACP). The inhibitory effect on the induction time and the rate of transformation to hydroxyapatite (HAP) varied greatly among the 23 Kampo medicines. We classified them according to their effects on increasing the induction time and/or decreasing the rate of HAP transformation. Ethane-1-hydroxy-1, 1-diphosphonate (EHDP) was used as the standard. This compound is a common toothpaste additive which decreases dental calculus formation. Two of the 23 Kampo medicines showed little or no inhibition either on the induction time or on the rate of HAP transformation. Twelve of them reduced the rate of HAP transformation by 20-40% and with 1.9- to 4.0-fold increases in the induction time. The remaining nine showed even greater activity. Keishi-ninjin-to (TJ-82), Dai-kenchu-to (TJ-100), Toki-to (TJ-102), Rikko-san (TJ-110) and San'o-shashin-to (TJ-113) showed the same inhibitory effect as EHDP. Shigyaku-san (TJ-35;5.2-fold), Dai-kanzo-to (TJ-84;4.9-fold), Oren-gedoku-to (TJ-15;12.7-fold) and Inchin-ko-to (TJ-135;9.5-fold) had a greater effect on the increase of induction time than EHDP and reduced the rate of HAP transformation by 50-60%. These results suggest that these nine kinds of Kampo medicines may have potential as anticalculus agents in toothpastes and mouthwashes.

Calcium↗
PubMed1993

The effects of tyramine on salivary flow rate and protein secretion by rat submandibular glands.

The effects of different doses of p-tyramine injected i.v. and i.p. on salivary flow rates and proteins secreted by the submandibular glands of rats were studied with and without various types of autonomic blockers and two enzyme inhibitors. The salivary flow rates and the amounts of protein secreted progressively increased with increasing doses injected both i.v. and i.p., whereas they were dramatically reduced with all autonomic blockers except the lowest doses of beta-blockers, atropine, and yohimbine. Salivation in response to p-tyramine injected i.v. and i.p. was completely abolished by simultaneous injections of both prazosin and propranolol. The concentration of protein was not dose-dependent and was not reduced by yohimbine and phenoxybenzamine at almost all doses used. However, prazosin significantly increased the protein concentration. Protease activities were dose-dependent but were significantly reduced with alpha-blockers other than yohimbine, and with most beta-blockers. The proteins secreted in response to p-tyramine at all doses injected i.v. and i.p. were of the alpha-type except with the lowest dose injected i.p. However, the alpha-type was completely replaced by the beta-type in the presence of all alpha-blockers except yohimbine, but not with beta-blockers, atropine, or two enzyme inhibitors. Pargyline, a monoamine-oxidase inhibitor, but not disulfiram, a dopamine-beta-hydroxylase inhibitor, affected all parameters except the type of protein. Thus, p-tyramine may activate both the alpha 1- and beta 1-adrenoceptors in the submandibular glands of rats directly or indirectly.

Adrenergic alpha-Antagonists↗
PubMed1993

[Ph1 positive myeloblastic crisis followed by Ph1 negative, bcr rearrangement positive T lymphoid crisis in a CML case].

A 26 year old Japanese male who had a history of leukocytosis in 1985 and received chemotherapy because of myeloblastic crisis of chronic myelogenous leukemia (CML) from May 1986, was admitted in November 1987. He had lymphadenopathy, lymphoid tumor of paranasal sinus and pleural effusion with marked lymphoid cells infiltration. On admission, laboratory data of peripheral blood and bone marrow revealed remission; lymphoid cells of pleural effusion were positive for CD3, CD4 and CD8. Second induction chemotherapy was performed successfully. After a few months, however, myeloblastic crisis recurred. Intensive chemotherapy ended in failure and he died of renal and heart failure. Chromosome analysis showed Ph1 and additional abnormalities at myeloblastic crisis and normal at T lymphoid crisis, but the same rearrangement of breakpoint cluster region existed in both crisis cells. Therefore we supposed that more than two-step pathogenesis is involved in the development of Ph1 positive or Ph1 negative CML clone of this patient.

Adult↗
PubMed1992

Inhibitory effect of prostaglandin oligomeric derivatives on 9,10-dimethyl-1,2-benzanthracene-induced hamster lingual carcinomas.

The inhibitory effects of prostaglandin oligomeric derivatives OC-3186 and OC-5186 were examined in hamster lingual carcinoma induced by 9,10-dimethyl-1,2-benzanthracene (DMBA). These compounds caused a regression of 40-90% in the size of lingual carcinomas in the hamster within several days after systemic or local administration.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Interleukin-2 production by primary adult T cell leukemia tumor cells is macrophage dependent.

We have investigated the cellular requirements for IL-2 production by autocrine proliferating tumor cells from four patients with adult T cell leukemia (ATL). Cultures of these ATL cells both produced endogenous IL-2 protein in the absence of added mitogen and proliferated at higher levels when exogenous recombinant IL-2 was added. Depletion of macrophages in the tumor cell cultures resulted in a sharp decline in tumor cell IL-2 production, while re-addition of macrophages reconstituted this response. Macrophage-derived factors including IL-6 and IL-1 also reconstituted IL-2 production in these macrophage depleted cultures. These results raise the possibility that macrophages may play a central role in HTLV-I mediated immortalization of T cells.

Blotting, Northern↗
PubMed1992

The effects of sodium lauryl sulphate and its oxidative breakdown products on calcium phosphate precipitation and transformation.

Most commercial dentifrices contain sodium lauryl sulphate, which oxidizes upon storage. The effects of aged sodium lauryl sulphate and its oxidative breakdown products on the conversion of amorphous calcium phosphate to hydroxyapatite were studied in vitro by a pH drop method. Hydroxyapatite was identified from its X-ray diffraction pattern. With storage time, the concentration of dodecanol [CH3(CH2)11OH], a breakdown product of sodium lauryl sulphate, increased. The storage dodecanol-containing sodium lauryl sulphate accelerated the conversion of amorphous calcium phosphate to hydroxyapatite. Dodecanol mixed with sodium lauryl sulphate accelerated the conversion when added both before and after initial formation of amorphous calcium phosphate. A stored commercial dentifrice also accelerated the conversion of amorphous calcium phosphate to hydroxyapatite. It was found that the concentration of dodecanol increased 2-fold over a 2-month period.

1-Butanol↗
PubMed1992

Hyperpolarizing interplexiform cell of the dace retina identified physiologically and morphologically.

One type of interplexiform cell (IPC) in the dace retina was discriminated physiologically from other cell classes and identified morphologically with HRP staining. This type responded with slow hyperpolarizing potentials to white diffuse light, and in addition a slow hyperpolarization (after potential) was observed after the cessation of light with relatively high intensities. The latency of the ON phase of the response was always longer than that of the second-order neurons and the amacrine cells. Morphologically, this type of IPC was similar in appearance with the dopaminergic IPC. The conventional synaptic specialization between this type of IPC and horizontal cells was observed, and the IPC was presynaptic.

Animals↗
PubMed1992

[A study on microproteinuria among diabetic and obese subjects without clinically overt proteinuria].

In metabolic disorders such as diabetes mellitus (DM) and obesity, renal abnormalities may also occur even when renal dysfunction is not be detected by conventional urinalysis. By use of immunological technique, an investigation was made on the subclinical abnormality in the excretion of urinary proteins in DM and obese (OB) subjects. Urinary excretion of the proteins (albumin, IgG, IgG4, beta 2-microglobulin) and fractional clearances (clearance ratios to creatinine clearance) at sitting position were respectively measured. Albumin excretion rate (AER) and fractional albumin clearance were higher in DM and OB than normal controls (NC). In non-diabetic subjects (OB+NC), body mass index (BMI) significantly positively correlated with AER and fractional albumin clearance. In DM, not only AER and fractional albumin clearance but also IgG4 excretion rate and fractional IgG4 clearance positively correlated with BMI. In DM with BMI less than 22 Kg/m2, HbA1C significantly correlated with AER, IgG4 excretion rate, and fractional albumin and IgG4 clearances. The data suggest that microproteinuria in DM and OB may be of glomerular origin. In DM, in the light of an increase in urinary excretion of negatively charged IgG4, it is also suggested that proteinuria is attributed to the alteration of charge barrier as well as to that of glomerular hemodynamics. Lastly but not least , obesity-related factor should also be taken into account in the development of microalbuminuria of the diabetic patient.

Adult↗
PubMed1991

Protection against cis-diamminedichloroplatinum-induced nephrotoxicity in rats by N-benzyl-D-glucamine dithiocarbamate.

Sodium N-benzyl-D-glucamine dithiocarbamate (BGD) was evaluated for its efficacy as an inhibitor of cis-diamminedichloroplatinum (DDP)-induced nephrotoxicity in a rat model. Treatment with 2.0 mmol/kg of BGD immediately after DDP injection effectively prevented nephrotoxic effects of DDP, but administration of BGD -1 or 1 h after DDP afforded a small protection. Concurrent treatment with 0.5 mmol/kg of BGD could not prevent renal damage. The platinum concentrations in liver and kidney were significantly decreased by BGD treatment. The antitumor efficacy of DDP in the Walker 256 carcinoma-bearing rats was not affected by administration of BGD (2.0 mmol/kg).

Animals↗
PubMed1991

A new method for the study of the formation and transformation of calcium phosphate precipitates: effects of several chemical agents and Chinese folk medicines.

A simple method of assaying the formation of amorphous calcium phosphate and its transformation to hydroxyapatite using a conventional pH meter and recorder is described. Its validity was confirmed by direct assay of calcium consumption with atomic absorption spectrophotometry. The method was used to study substances which influence the formation of amorphous calcium phosphate and its transformation to hydroxyapatite, such as albumin, casein, chondroitin sulphate, phospholipid, ATP, Mg2+, Sr2+, pyrophosphate and several Chinese folk medicines.

Adenosine Triphosphate↗
PubMed1991

The complete nucleotide sequence of cucumber green mottle mosaic virus (SH strain) genomic RNA.

The complete nucleotide sequence of the genomic RNA of cucumber green mottle mosaic virus watermelon strain SH (CGMMV-SH) was determined using cloned cDNA. This sequence is 6421 nucleotides long containing at least four open reading frames, which correspond to 186K, 129K, 29K and 17.3K proteins. The 17.3K protein is the coat protein. Sequence analysis shows that CGMMV-SH is very closely related to another watermelon strain. CGMMV-W, although three amino acid substitutions in the 29K protein were found between these strains. The sequence was also compared to those of other tobamoviruses, tobacco mosaic virus (TMV) vulgare, TMV-L (a tomato strain) and tobacco mild green mosaic virus reported by other groups. It shows 55 to 56% identity with these viruses. The size and location of the open reading frames are very similar to those of TMV but the 129K and 186K proteins are composed of 1142 and 1646 amino acids, being larger than those of TMV by 27 and 31 amino acids, respectively. The deduced amino acid sequences of these proteins are highly homologous to those of TMV, especially in the readthrough downstream region of the 186K protein.

Amino Acid Sequence↗
PubMed1991

[The analysis of leukemic relapse after allogeneic bone marrow transplantation].

This report presents the analysis of leukemic relapse of 52 patients who received allogeneic bone marrow transplantation between July 1984 and May 1990. Conditioning regimen consisted of TBI + CY and GVHD prophylaxis consisted of cyclosporin-A and methotrexate. The relapse ratios of chronic myelogenous leukemia (CML) (21 in chronic phase, 1 in accelerated phase, 1 in blastic crisis), acute nonlymphocytic leukemia (ANLL) (all 17 in 1st CR), acute lymphocytic leukemia (ALL) (all 12 in 1st CR) were 13%, 18%, 25%, respectively, and 3 year disease free survival (DFS) was as follows, CML 68%, ANLL 72%, ALL 49%. Regarding acute GVHD grading and chronic GVHD presence, 3 year DFS was as follows, acute GVHD 0 degree: 59%, I degree: 78%, II degree-IV degree: 53%, chronic GVHD (+): 82% GVHD (-): 77%. In our center leukemic relapse has been the major cause of death after BMT since 1984. Among 9 relapsed cases, one recurred more than 3 years after BMT, and another one got recurrent leukemia of donor origin.

Adolescent↗