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Biomedical subjects

A Ikawa

Publications and source records attributed to A Ikawa.

11 recordsLinked to original sources
PubMed2006

Causes of death and renal tubular dysfunction in residents exposed to cadmium in the environment.

OBJECTIVES: To clarify the causes of death of residents with renal tubular dysfunction induced by cadmium (Cd) in the environment. METHODS: A 15 year follow up study was performed with the inhabitants living in the Cd polluted Kakehashi River basin in Japan. Standardised mortality ratios (SMRs) for causes of death, classified by ICD-9, were computed using the person-years method to investigate the excess mortality of subjects with urinary beta2-MG (microglobulin) > or =1000 microg/gCr. Mortality risk analysis was performed using Cox's proportional model to compare mortality between subjects with urinary beta2-MG > or =1000 and <1000 microg/gCr, and to investigate the relationship between the degree of urinary beta2-MG and mortality. RESULTS: Excess mortality due to heart failure and cerebral infarction in both sexes, and nephritis and nephrosis in men, was observed among subjects with urinary beta2-MG > or =1000 microg/gCr. Significant increases in mortality risk for cerebral infarction in men and for malignant neoplasms in women with urinary beta2-MG > or =1000 microg/gCr were observed during the first five year observation period. For nephritis and nephrosis, the mortality risks for men and women with urinary beta2-MG > or =1000 microg/gCr significantly increased over the 15 year observation period. The mortality risks for heart failure and cerebral infarction increased in proportion to the increased urinary beta2-MG in both sexes. Increased mortality risks for nephritis and nephrosis were identified in the subjects with urinary beta2-MG > or =10000 microg/gCr in both sexes. CONCLUSION: Renal tubular dysfunction induced by Cd affected the causes of death, and mortality for heart failure, cerebral infarction, and nephritis and nephrosis was increased among inhabitants living in a Cd polluted area in Japan. In women, cancer mortality may have been increased while Cd pollution was ongoing.

Aged↗
PubMed2002

Age-related changes in the dorsal skin histology in Mini and Wistar rats.

Mini rats (Jcl: WistarTGN(ARGHGEN)1Nts (MRs) are Wistar rat (WR)-derived transgenic rats in which the expression of growth hormone (GH) gene is suppressed by the presence of antisense transgene. The plasma GH level of MRs is reduced to 40 to 60% of that of WRs. In this study, to evaluate the influence of GH deficiency on the skin nature, age-related changes in the dorsal skin histology were compared between male MRs and WRs. Although there were no essential differences in the skin structures between the two strains, MRs had thinner skin with less collagens, more abundant subcutaneous adipose tissues and small-sized sebaceous glands compared with WRs. On the other hand, the hair cycle evaluated by the morphology and the depth of hair follicles was greatly different between them. Namely, two cycles of 4 weeks each were observed in both strains during the first 8 weeks after birth, but the cycle entered a long-lasting quiescence (telogen phase) in MRs while the 3rd cycle started in WRs afterwards. The lower level of serum insulin-like growth factor (IGF)-1 in MRs may be related to such a difference in hair cycle pattern, although the levels of IGF-1 and IGF-1 receptor mRNAs in the dorsal skin tissues were similar between MRs and WRs. MRs are considered to be a useful animal model for dermatopathy in patients suffering from GH deficiency and for grasping a clue to elucidate the exact effects of GH on the skin nature, especially on hair follicle development.

Aging↗
PubMed1999

[Treatment of cancer ascites by combined intraperitoneal administration of low-dose CDDP and reinfusion of ultra-filtrated and concentrated ascitic fluid in patients].

Ascites due to carcinomatous dissemination is a severe problem for end-stage cancer patients. We attempted treating patients on an outpatient basis with the administration of low-dose CDDP-i.p. and reinfusion of ultrafiltrated and concentrated ascites. From 1995, we performed this therapy on 16 patients with concentrated ascites 6-8 fold and reinfusion, combined with low-dose CDDP-i.p. and drip infusion of 5-FU intravenously. The ascitic fluid was significantly decreased after treatment in 8 patients, and 2 patients had lasting low concentrations of CA 125. CA 125 decreased in 83.3% of patients, who tended to have extended survival times after remarkable ascites pooling and treatment with low-dose CDDP-i.p. and reinfusion therapy. This treatment is a useful cant method for decreasing ascites and improving QOL.

Adult↗
PubMed1994

[Phosphate ion-exchange with hydrotalcite-like compound in the presence of trypsin].

A Cl(-)-intercalated hydrotalcite-like compound (HTAL) is a promising material as a better phosphate adsorbent for further clinical use than the currently marketed aluminum hydroxide gels. In the preceding study, we found that Cl- ions in the interlayer of HTAL can be exchanged with phosphate ions equivalently. In the present study, we have investigated the adsorption of porcine pancreas trypsin on HTAL and the influence of trypsin adsorption on the phosphate/Cl- ion-exchange properties of HTAL. The isotherm for trypsin adsorption at 310K and pH 8.4 showed the curve of BDDT V type and gave an adsorption capacity of 88.6 mg/g for trypsin. The zeta-potential analysis of HTAL suggested that the trypsin adsorption on HTAL at pH 8.4 was restrained by the electrostatic repulsion between HTAL surface and trypsin with positive charge. XRD and nitrogen adsorption studies showed that trypsin was adsorbed on the external surface of HTAL by occupying the area (ca. 22 nm2) per trypsin molecule. The phosphate/Cl- ion-exchange reaction with HTAL was not affected by the presence of trypsin; the phosphate ion-exchange capacity reached 73.6 mg P/g from the solution containing 3200 mg trypsin/dm3. On the other hand, the trypsin adsorption was significantly depressed by the loading of phosphate ions. The XRD analysis of the phosphate-loaded HTAL revealed that the layered structure of hydrotalcite holds after the phosphate ion-exchange, but shows a slight increase of the interlayer distance from 0.3 nm to 0.5 nm by the intercalation of phosphate ions.

Adsorption↗
PubMed1993

Mechanism of phosphate adsorption to a three-dimensional structure of boehmite in the presence of bovine serum albumin.

A new microcrystalline boehmite (tentatively named PT-A) was synthesized as an efficient phosphate adsorbent to replace aluminum hydroxide gel. The characteristic structure of PT-A was examined by nitrogen adsorption/desorption, X-ray diffraction, deviation microscopy, and scanning electron microscopy to establish a pore structural model of PT-A. With this model structure, the details of the mechanism of interaction between PT-A and phosphate in the presence of bovine serum albumin (BSA) are discussed. PT-A is a spherical particle with a diameter of approximately 100 microns and a porous surface structure, and its inside is packed with boehmite microcrystals (crystallite size, 2 nm). PT-A has three types of pores in its structure: a micropore with a narrow size-distribution, a mesopore with a broad size-distribution, and a macropore (radii of pores are 0.7, 1-20, and approximately 300 nm, respectively). When phosphate was incubated with PT-A in human gastric and intestinal juices or in an aqueous solution containing BSA, the amounts of phosphate adsorbed by PT-A were not affected by the presence of proteins. The nitrogen adsorption/desorption isotherms and energy dispersive X-ray analyses demonstrated that phosphate could diffuse to the smaller tunnels freely even if the external surface of PT-A was covered with BSA. It was also demonstrated that the main site of adsorption for phosphate was in micropores of PT-A, whereas BSA was adsorbed only to the external surface and none entered inside smaller tunnels consisting of micro- and mesopores.

Adsorption↗
PubMed1992

Interaction of bovine serum albumin with the surface of a microcrystalline aluminum oxide hydroxide compound: a possible new type of phosphate adsorbent.

Aluminum hydroxide gel (ALG) has been effective for ameliorating acidosis associated with phosphatemia caused by hemodialysis. However, aluminum accumulation in the body causes severe side effects. As substitute for ALG, a new type of aluminum oxide hydroxide (tentatively named PT-A) was prepared with the hope of future clinical use. PT-A has a microcrystalline structure with a high resistance to pH change and has more phosphate-binding efficacy than ALG. It was tested for possible interaction with protein by adsorption test, zeta-potential analysis, X-ray diffraction, and scanning electron microscopy. Bovine serum albumin (BSA) was chosen as a model protein. The interaction of BSA with PT-A depended on the amount of adsorbent. Protein adsorption occurred rapidly and reached the maximal level at near neutral pHs. Phosphate adsorption was not affected by the presence of BSA, but the interaction of BSA with PT-A was significantly reduced by the presence of phosphate. Zeta-potential changes on the surface of PT-A indicated that the positively charged surface of PT-A was covered with negatively charged phosphate ions that repelled negatively charged BSA molecules. X-ray diffraction patterns indicated no observable structural alteration caused by adsorption of BSA or phosphate, and scanning electron microscopy revealed that BSA covered the outer surface of PT-A but did not cover small pores, where phosphate can freely penetrate.

Adsorption↗
PubMed1990

Phosphate and pepsin adsorptions by a new boehmite compound and aluminum hydroxide.

A new microcrystalline compound of aluminum oxide hydroxide (tentatively named PT-A) was synthesized in the hope of providing a better phosphate adsorbent for future clinical use than the currently marketed aluminum hydroxide gels (ALG). An X-ray diffraction study demonstrated a boehmite structure in PT-A but an amorphous structure in ALG. PT-A was more stable in pH change than ALG; in elution tests in artificial gastric and intestinal solutions, aluminum ion eluted from PT-A was maximally 10% of the amount from ALG at pH 1.2; and was undetectable at pH 6.8, at which point ALG still showed some aluminum elution. Phosphate-adsorbing efficacy of PT-A and ALG in vitro was about the same at pH 1.2; however, it was four times greater in PT-A than in ALG at pH 6.8, indicating that PT-A will be effective in the intestine. PT-A also adsorbed pepsin but the amount was at most the same or much less than that adsorbed by ALG, which depended on pH in solution.

Adsorption↗
PubMedDate not supplied

Cerebral amyloid angiopathy in an aged great spotted woodpecker (Picoides major).

A male great spotted woodpecker (Picoides major), which was at least 16 years old, died due to general weakening. Cerebral vascular walls, including capillaries, were positively stained with Congo red with green-gold birefringence, and some of which showed a severe deposition of the Congophilic materials resulting in a corona-like fibrillar radiating structure. The Congophilic materials were positive for beta amyloid protein, but negative for prion protein. Only a few senile plaque-like structures were observed in the cortex by PAM stain and beta amyloid immunostain. The present case is the first observation of cerebral amyloid angiopathy in avian species and will indicate the presence of such age-related cerebral lesions also in birds.

Animals↗