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H Monma

Publications and source records attributed to H Monma.

10 recordsLinked to original sources
PubMed2002

Interaction between hydroxyapatite and proteins by liquid chromatography using simulated body fluids as eluents.

Hydroxyapatite (HAp) column chromatography for proteins using simulated body fluids (SBFs) as eluents was investigated in order to mimic the flow environment of human body fluid on the HAp surface in vivo. Acidic plasma proteins such as albumin, gamma-globulin, and fibrinogen having carboxyl groups with a negative charge were suggested to adsorb at positively charged sites (Ca sites) on the HAp surface. These acidic plasma proteins were not even eluted at higher inorganic ion molarities of human body fluid. Whereas basic proteins such as papin, cytochrome c, and lysozyme were easily eluted at lower inorganic ion molarities of human body fluid due to existing Na(+), Ca(2 +), Mg(2 +) and (CH(2)OH)(3)CNH(4)(+) ions in the eluents. The elution behavior of proteins using SBF in the presence or absence of glucose did not change. From these considerations, bone matrix proteins as acidic and neutral proteins would be considered an advantageous condition in order to adsorb on HAp in vivo.

Journal Article↗
PubMed2001

Adsorption characteristics of proteins on calcium phosphates using liquid chromatography.

The adsorption characteristics of various proteins on beta-Ca(3)(PO(4))(2) (beta-TCP), CaHPO(4). 2H(2)O (DCPD) and CaHPO(4) (DCPA) have been investigated using liquid chromatography. Acidic proteins were eluted from these calcium phosphate surfaces by potassium phosphate buffer (KP) but not by KCl and MgCl(2), whereas basic proteins were eluted by all three eluents. Such elution behavior can be interpreted by considering two kinds of adsorbing sites on the calcium phosphates, namely positively charged sites (Ca sites) which adsorb acidic proteins, and negatively charged sites (P sites) which adsorb basic proteins. A similar behavior has also been observed on Ca(10)(PO(4))(6)(OH)(2) (HAp) and Ca(8)H(2)(PO(4))(6). 5H(2)O (OCP). The order of the ratios of Ca-to-P sites was estimated to be DCPD > OCP > HAp >> DCPA >> beta-TCP, which is in agreement with the order of the surface zeta potentials. In addition, the (0k0) surface of DCPD is suggested to consist mainly of Ca sites. The total number of Ca sites on beta-TCP is thought to be significantly smaller than the other calcium phosphates.

Adsorption↗
PubMed2001

Preparation and microstructure analysis of chitosan/hydroxyapatite nanocomposites.

Chitosan/hydroxyapatite (HAp) composites with a homogeneous nanostructure have been prepared by a co-precipitation method. According to TEM observations, HAp crystallites in the composites formed elliptic aggregations 230 nm in length and 50 nm in width. The typical length of the aggregations corresponded approximately to that of a chitosan molecule. The size of the constituent HAp crystallites was found to be predominantly 30 nm in length and 10 nm in width, and the c-axes were well aligned in parallel with the chitosan molecules in the respective aggregations. The growth of the HAp crystallites is considered to occur at nucleation sites, most probably forming the complexes with amino groups on chitosan with calcium ions. The compact composites obtained have been found to be mechanically flexible, and this flexibility has been improved further by heating at 120 degrees C for 20 min in an autoclave with saturated steam pressure.

Biocompatible Materials↗
PubMed2001

Is the mechanism of traumatic posterior dislocation of the hip a brake pedal injury rather than a dashboard injury?

This study proposes that the mechanism of traumatic posterior dislocation of the hip (TPDH) is a brake pedal injury rather than a dashboard injury. A total of 168 cases of TPDH were treated during the past 10 years. Clinical records of 48 patients, who were drivers and suffered from a head-on collision accident, were examined. The right hip was involved in 45 cases. A total of 31 cases were not accompanied by knee injuries. In 11 cases with foot or ankle injuries and right hip dislocation, 10 had right foot or ankle injuries. If the mechanism of TPDH was a dashboard injury, the left hip would be involved more frequently and there would be more knee injuries. Our hypothesis about the mechanism is that, in a head-on collision, the driver presses desperately on the brake pedal with his right hip slightly flexed, adducted and internally rotated.

Accidents, Traffic↗
PubMed2000

The Surface Structure of Hydroxyapatite Single Crystal and the Accumulation of Arachidic Acid.

Single crystals of hydroxyapatite (HAp) were grown by a flux method using beta-tricalcium phosphate and Ca(OH)(2) under hot isostatic pressure. After chemical etching by 0.05 N HCl aqueous solution, the HAp crystal surfaces were observed by an atomic force microscope (AFM) and shown dominantly to consist of steps with heights corresponding to a lattice distance d(100) or its 2/3. Arachidic acid films were accumulated on the etched HAp crystal by a Langmuir-Blodgett method. From section analyses by AFM, a distance between the carboxyl groups of arachidic acid and the HAp surface was estimated to be approximately 0.04 nm, sufficiently adjacent for a chemical interaction to take place. Copyright 2000 Academic Press.

Journal Article↗
PubMed1986

High-performance liquid chromatography using spherical aggregates of hydroxyapatite micro-crystals as adsorbent.

High-performance liquid chromatography (HPLC) using spherical aggregates of hydroxyapatite (HA) microcrystals as adsorbent has been developed; preliminary performance tests were carried out by using several types of protein. In comparison with previously developed plate-like HA packed columns for HPLC, spherical HA packed columns show considerably high chromatographic resolutions in spite of extremely reduced column lengths of 0.5-3 cm. The pressure generated by the latter columns is much higher than that generated by the former, however.

Adsorption↗
PubMed1985

Effect of captopril on heavy proteinuria in azotemic diabetics.

We investigated whether captopril, an angiotensin-converting-enzyme inhibitor, would reduce proteinuria in patients with advanced diabetic nephropathy. Captopril (37.5 mg given in divided doses three times daily) was administered to 10 azotemic diabetics with heavy proteinuria. Urinary protein decreased promptly within two weeks (from 10.6 +/- 2.2 to 6.1 +/- 1.4 g per day [mean +/- S.E.M.]; P less than 0.01). The decrease in proteinuria did not coincide with a fall in systemic blood pressure or in the blood glucose concentration. Serum creatinine and potassium values did not change in any of the patients except one. We suggest that captopril caused a decrease in intrarenal hypertension, which contributed to the reduction of urinary protein excretion. The therapeutic value of this intervention remains to be established.

Adult↗