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Biomedical subjects

F Kametani

Publications and source records attributed to F Kametani.

At least 55 records · Page 3Linked to original sources
PubMed1989

Inhibitory effects of phenol derivatives on bovine platelet aggregation and their effects on Ca2+ mobilization.

The effects of phenol derivatives on aggregation of bovine platelets induced by ADP, thrombin, platelet activating factor, collagen and A23187 were investigated. The phenol derivatives inhibited all these induced aggregations except that by the calcium ionophore. The derivatives each inhibited the aggregations induced by ADP, thrombin, platelet activating factor and collagen, respectively, within a similar concentration range. A linear relation was found between the inhibitory potencies of the phenol derivatives and their partition coefficients between n-octanol and water (Poct values), suggesting that their interaction with hydrophobic regions of the cell was important for inhibition. Fluorescence analyses with fura-2-loaded platelets showed that in the concentration ranges in which the phenol derivatives inhibited aggregation, they also inhibited agonist-induced increases in Ca2+ both in the presence and absence of extracellular Ca2+. Moreover, a high correlation was found between the inhibitory effects of the derivatives on aggregation and their effects on Ca2+ mobilization. These results suggest that inhibition of platelet aggregation by phenol derivatives is mainly due to inhibition of the increase in cytoplasmic Ca2+ by inhibition of both intracellular Ca2+ mobilization and Ca2+ uptake.

1-Octanol↗
PubMed1987

Inhibitory effects of long-chain alkyltrimethylammonium ions on aggregation of bovine platelets and the relation of their effects to Ca2+ mobilization.

The inhibitory effects of alkyltrimethylammonium ions on ADP- and thrombin-induced aggregation of bovine platelets were investigated. The ammonium cations inhibited the two aggregation reactions to similar extents. The relationship between their inhibitory effects on ADP-induced aggregation and their alkyl chain lengths from C8 to C18 was investigated. Results showed that the inhibitory effects of ammonium cations increased with increase of their alkyl chain lengths up to C16, and that the increase was linear with chain lengths of up to C14. This linear relation and slope of the linear regression line suggested that the inhibitory effects of the ammonium cations depended on their partitioning into the membrane. However, unlike long-chain unsaturated fatty acids, they did not affect the membrane fluidity of the platelets. Fluorescence analysis of fura-2 loaded platelets revealed that, in the concentration range where the alkyltrimethylammonium ions inhibited aggregation, they inhibited agonist-induced increase in cytosolic Ca2+ both in the presence and absence of extracellular Ca2+. These results suggest that inhibition of platelet aggregation by alkyltrimethylammonium ions is mainly due to their inhibition of increase in cytoplasmic Ca2+ by inhibition of both intracellular Ca2+ mobilization and Ca2+ uptake.

Adenosine Diphosphate↗
PubMed1987

Relationship of the effects of nigericin on the aggregation and cytoplasmic pH of bovine platelets in the presence of different cations.

The effect of nigericin on aggregation of bovine platelets was investigated in media containing the chloride salts of various alkali metal cations of quaternary ammonium cations. In medium with K+, which has the highest permeability with the ionophore among the cations tested, nigericin slightly enhanced both ADP- and thrombin-induced aggregation. In medium with Na+, nigericin scarcely affected ADP-induced aggregation, and slightly inhibited thrombin-induced aggregation. In media with Cs+, choline and tetramethylammonium, it inhibited the aggregations induced by both ADP and thrombin. Measurement of the cytoplasmic pH with the fluorescent probe 2',7'-bis(carboxyethyl)5,6-carboxyfluorescein showed that nigericin increased the intracellular pH in K+ medium and caused its stable decrease (of about 0.6) in Cs+, choline and tetramethylammonium media, but caused only a small transient decrease in medium with Na+. These results suggest that the effects of nigericin on platelet aggregation are mainly due to its effects on the cytoplasmic pH. This conclusion is supported by the findings that the effects on platelet aggregation of other types of ionophore tested were also proportional to their effects on the cytoplasmic pH.

Adenosine Diphosphate↗
PubMed1985

Effects of long-chain cis-unsaturated fatty acids and their alcohol analogs on aggregation of bovine platelets and their relation with membrane fluidity change.

The effects of long-chain cis-unsaturated fatty acids with different alkyl chain lengths and different numbers of double bonds on aggregation of bovine platelets and membrane fluidity were investigated. All the cis-unsaturated fatty acids tested inhibited aggregation and at the same time increased membrane fluidity in accordance with their inhibitory effects. The saturated fatty acids and trans-unsaturated fatty acid tested for comparison had much lower or no effects on aggregation and membrane fluidity. The inhibitory effects of mono cis-unsaturated fatty acids increased with increase of their alkyl chain length. cis-Unsaturated fatty acids with two or more double bonds had more inhibitory effects than mono-unsaturated fatty acids. The position of the double bonds had less influence than the number of double bonds. We also examined the effects of cis-unsaturated fatty acids on membrane fluidity with diphenylhexatriene and anthroyloxy derivatives of fatty acids as probes and observed increased fluidity to be considerable in the membrane. The alcohol analogs of cis-unsaturated fatty acids also inhibited aggregation and increased membrane perturbation. These results suggest that the inhibition of platelet aggregation by cis-unsaturated compounds is due to perturbation of the lipid layer.

Adenosine Diphosphate↗
PubMed1985

Effects of monovalent cations and anions on ADP-induced aggregation of bovine platelets, and mechanisms thereof.

The effects of monovalent cations-inorganic alkali metal cations and organic quaternary ammonium cations-and monovalent inorganic anions on ADP-induced aggregation of bovine platelets were investigated. In the presence of K+, Rb+, Cs+, choline or tetramethylammonium, aggregation proceeded. However, aggregation was markedly restricted in media containing Li+, Na+, tetrabutylammonium or dimethyldibenzylammonium. With anions, aggregation proceeded in the order Cl- greater than Br- greater than I- greater than ClO4- greater than SCN-. The effects of cations significantly depended on Ca2+ concentration, whereas those of the anions depended little on Ca2+. Anions such as SCN- and ClO4- markedly decreased the fluorescence of the surface charge probe 2-p-toluidinyl-naphthalene-6-sulfonate, whereas cations had less pronounced effects. The relative effects of the anions on the fluorescence were consistent with their relative inhibitory effects on aggregation. These results suggest that inhibition of platelet aggregation by the anions is due to a change in the surface change of the platelet plasma membrane. On the other hand, kinetic analysis suggests that the effects of monovalent cations on platelet aggregation are due to their competition with Ca2+ during the process of aggregation.

Adenosine Diphosphate↗
PubMed1985

Amino acid sequence of an amyloidogenic Bence Jones protein in myeloma-associated systemic amyloidosis.

The complete amino acid sequence of an amyloidogenic Bence Jones protein (NIG-84) from an individual with myeloma-associated systemic amyloidosis has been determined. The protein, with a blocked N-terminus, represents a complete light chain consisting of 217 residues and it has a structural feature characteristic of the V lambda II subgroup. In addition to a two-residue insertion at positions 28 and 29, it has an additional rare insertion of alanine at position 100. NIG-84 is an example of the first complete sequence presented for the amyloidogenic Bence Jones protein of the V lambda II subgroup.

Amino Acid Sequence↗
PubMed1985

Primary structure of the variable region of an amyloidogenic Bence Jones protein NIG-77.

The complete amino acid sequence of the variable region of a Bence Jones protein NIG-77 from an individual with myeloma-associated systemic amyloidosis has been determined. This protein represents a complete light chain consisting of 216 residues and it has a sequence characteristic of V lambda I subgroup, which is closely homologous to that of another amyloidogenic V lambda I Bence Jones protein NIG-51, differing by 20 of 111 residues (82% homology). In contrast, it differs by 29 residues (74% homology) to that of non-amyloidogenic V lambda I light chain NIG-64. This finding shows that, in accordance with our previous report(1), the V lambda I-related light chains can further be divided into two distinct subsubgroups, V lambda I-1 and V lambda I-2, and the latter property seems to be more prone in association with the amyloid process.

Amino Acid Sequence↗
PubMed1985

Complete amino acid sequence of a unique protein related to the variable domain of lambda light chain from a case with Fanconi syndrome.

The complete amino acid sequence has been determined of a unique protein from a 55-years-old female with multiple myeloma associated with Fanconi syndrome. It existed in a monomer form with an apparent molecular weight of 10K daltons, and was consisted of 106 amino acid residues. The sequence was characteristic of the V-region of lambda light chains and was highly homologous with that of the first 106 residues of V lambda III subgroup. The presence of an intact light chain as well as a 13K daltons fragment, corresponding to the entire C-region, strongly suggests that the unique component is a catabolic product from the intact light chain rather than an aberrant product of synthesis.

Amino Acid Sequence↗
PubMed1985

Quantitative determination by derivative spectrophotometry of Triton X-100 in solubilized preparations of membrane proteins.

The amount of the nonionic detergent Triton X-100 in protein preparations cannot be determined spectrophotometrically from the normal spectrum because the spectral bands of the detergent and proteins overlap, but it was found that the detergent could be determined accurately by 4th-derivative spectrophotometry. The intensity of the derivative absorbance difference between the positive and negative peaks at about 277.5 and 281 nm, respectively, increased linearly with increase in the detergent concentration at more than its critical micelle concentration (about 0.03%). Proteins had little effect on these spectral bands of the detergent. This method is very simple and accurate for determination of the concentration of Triton X-100 in solubilized preparations of membrane proteins.

Animals↗
PubMed1984

A variant prealbumin-related low molecular weight amyloid fibril protein in familial amyloid polyneuropathy of Japanese origin.

Amyloid fibril protein with a molecular weight of 8K daltons, in addition to one of 16K daltons, has been isolated and characterized from an autopsy sample of a patient with familial amyloid polyneuropathy in a Japanese family from Ogawa Village, Nagano Prefecture. The component was shown to react with an antiserum to normal plasma prealbumin, as did the other. Following the purification by reverse phase liquid chromatography, it was digested with trypsin and the peptides, after the purification by HPLC were sequenced. The data showed that the component was a distinct fragment whose sequence was identical with that of the residues from Gly-6 to Tyr-78 of the prealbumin, except that it had a methionine for a valine at position 25. This corresponded with the position 30 where a valine residues has been reported for the sequence of the normal plasma prealbumin.

Amino Acid Sequence↗
PubMed1984

Activation of bovine platelets induced by long-chain unsaturated fatty acids at just below their lytic concentrations, and its mechanism.

The effects of long-chain unsaturated fatty acids such as linoleic acid on bovine platelets were examined. Not only linoleic acid, but also oleic and linolenic acid, at just below the concentrations causing marked cell lysis, induced an absorbance decrease of the platelet suspension in the presence of Ca2+. Since this absorbance decrease was reversed by the addition of EDTA and moreover aggregate formation was found by macroscopic and microscopic observation, it was concluded that unsaturated fatty acids at just below their lytic concentrations caused platelet aggregation. Unsaturated fatty acids also caused release of adenine nucleotides, but there was a lag time between the release and the aggregation, just as with ADP-induced release, suggesting that the aggregation was independent of the release of ADP. It was revealed that this activation of platelets by unsaturated fatty acids was caused by marked Ca2+ uptake into the cytoplasm, resulting from significant membrane perturbation.

Adenosine Triphosphate↗
PubMed1984

Inhibition of ADP-induced aggregation of bovine platelets by saturated fatty acids and its relation with the change of membrane surface charge.

The inhibitory effects of saturated fatty acids with 4 to 18 carbon atoms on ADP-induced aggregation of bovine platelets were investigated. The inhibitory effects of the acids increased with increase of their alkyl chain length up to C14. On the other hand, from C16 the inhibitory effects tended to decrease with increase of chain length, and stearic acid (C18) was not inhibitory. There was a linear relationship between the inhibitory effects and alkyl chain lengths up to C12. This linear relation and the slope of the linear regression line suggested that the inhibitory effects of the acids depended on their partition into the membrane. The fatty acids decreased the fluorescence of the surface charge probe 2-p-toluidinylnaphthalene-6-sulfonate, indicating that they increased the negative charge on the membrane surface. The relative effects of the acids on the fluorescence were consistent with their relative inhibitory effects on aggregation. These results suggest that the inhibition of platelet aggregation by saturated fatty acids is due to a change in the membrane surface charge of the platelet plasma membrane.

Adenosine Diphosphate↗
PubMed1984

Effects of four types of reagents on ADP-induced aggregation and Ca2+ mobilization of bovine blood platelets.

The effects of four types of reagents--a stimulant analog (ATP), reagents increasing cAMP (theophylline and (-)-isoproterenol), Ca2+ blockers (chlorpromazine, procaine, dibucaine and tetracaine) and nonspecific membrane-reactive reagents (n-butanol, n-hexanol and linoleate) - on ADP-induced Ca2+ mobilization and aggregation of platelets were investigated. All the reagents tested inhibited the aggregation. Of these reagents, those increasing cAMP and the stimulant analog inhibited the aggregation at least partly by inhibiting Ca2+ mobilization, whereas Ca2+ blockers and nonspecific membrane-reactive reagents must have inhibited the aggregation by different mechanisms, because they had: (1) no effect on ADP-induced Ca2+ mobilization, (2) accelerated it, or (3) themselves stimulated Ca2+ mobilization. The results showed that the inhibitory effects of Ca2+ blockers were at least partly due to competition with Ca2+ for binding sites on the outside of the membrane, whereas the effects of the nonspecific membrane-reactive reagents tested were due to membrane perturbation.

Adenosine Diphosphate↗
PubMed1984

Effects of alcohols on ADP-induced aggregation and membrane fluidity of gel-filtered bovine blood platelets.

The effects of four alcohols--n-propyl, n-butyl, n-amyl and n-hexyl alcohol--on the ADP-induced aggregation of gel-filtered bovine platelets were examined. All four alcohols inhibited the aggregation, the order of their effects being n-propyl less than n-butyl less than n-amyl less than n-hexyl. Comparison of the inhibitory effects of the alcohols with their physico-chemical properties showed that their degrees of inhibition depended on their hydrophobicities. Moreover, it was suggested that their interaction with the lipid layer of the membrane was important for the inhibition. Studies on the effects of alcohols on the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene-labeled platelets showed that the membrane fluidity of the platelets increased in the same concentration range in which aggregation inhibition was observed. Since the alcohols inhibited aggregation without affecting Ca2+ mobilization in the platelets, as revealed in this study, it was concluded that inhibition of platelet aggregation was due to perturbation of membrane lipids by the alcohols. This hypothesis is supported by several recent studies on the effects of cholesterol and cations, which suggest that a relatively rigid membrane favors platelet aggregation.

1-Butanol↗
PubMed1983

A new immunoglobulin marker.

In an examination of 16 human immunoglobulin lambda-light chains, one was found to have amino acid substitutions which have not previously been reported for the constant region of the lambda-chains. It involved in two positions: an arginine instead of lysine at position 130, and a leucine for glutamine at position 195 (Sh numbering (1) ). The structural variation is tentatively designated as "Is" marker.

Amino Acid Sequence↗
PubMed1983

Inhibitory effects of 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) on the ADP-stimulated aggregation of gel-filtered bovine blood platelets.

The effect of DIDS, a specific inhibitor of anion transport in the erythrocyte membrane, on the ADP-stimulated aggregation of gel-filtered bovine blood platelets was examined. Marked inhibition of aggregation was observed at concentrations of more than 5 x 10(-5)M DIDS. On preincubation with platelets for 30 min, DIDS was more potent and significant inhibition was observed at concentrations of over 2 x 10(-7)M. Since ADP-stimulated aggregation of bovine gel-filtered platelets precedes the release reaction, these results suggest that an anion transport system in the plasma membrane is involved in platelet aggregation.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗