Magnetite (Fe3O4) microcapsules prepared using a glass membrane and solvent removal

Fine magnetite powders dispersed in polymer solution were encapsulated from an oil-in-water emulsion prepared by an emulsification process employing a porous glass membrane and subsequent evaporation of the solvent. Styrene-based copolymers were dissolved in a magnetic fluid, and then continuously pushed through the pores of glass membrane into the aqueous phase, which had dissolved polyvinyl alcohol (PVA) and sodium dodecyl sulphate (SDS) as a mixed stabilizer. P(styrene-co-acrylic acid) (PS-AA), P(stryrene-co-butyl acrylate) (PS-BA) and styrene-butadiene rubber (SBR) were dissolved in the specially ordered magnetite fluid (25 wt% magnetite dispersed in toluene) separately or as a mixture, and uniform droplets suspending the magnetic particles were obtained. After the evaporation of toluene, PS-AA capsules retained a spherical shape and uniformity, whereas PS-AA/PS-BA capsules revealed a creased surface and broader size distribution. The microcapsules entrapped 30-40 wt% of magnetite, and the encapsulation yield of magnetite was 20-40%. Glass membranes with 9.5, 5.25 and 1.42 microm pore size were employed and 5-40 microm microcapsules were obtained depending on the pore size. When magnetite suspended in chloroform was used, magnetite capsules with broader size distributions were obtained because of the sticking of the droplets to the membrane wall. The advantage of the membrane emulsification which provides uniform sized droplets was lost.

[Economical evaluation for drug consultation at home]

We started drug consultation at patients' homes in October, 1998. The number of drug consultations are 2.65 per month per patient and the consulting time is 2.25 hours per patient. The fee for drug consultation is 550 points twice a month. We evaluate the fee for drug consultation. Our data suggest that this fee needs to be 550 points three times a month.

Activation of progelatinase B in synovial fluids of patients with rheumatoid arthritis, with reference to stromelysin-1 and tissue inhibitor of matrix metalloproteinase-1

OBJECTIVE

To clarify whether stromelysin-1 and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) are involved in the modulation of activation of progelatinase B in the synovial fluid of patients with rheumatoid arthritis (RA).

METHODS

Gelatinases in the synovial fluid of patients with RA were analyzed by gelatin zymography. Concentrations of stromelysin-1 and TIMP-1 were measured using a specific sandwich enzyme linked immunosorbent assay.

RESULTS

Forty-three rheumatoid synovial fluids containing progelatinase B were examined to clarify whether the enzyme was activated by incubation. Incubation at 37 degrees C caused the conversion of progelatinase B to the active form in 22 of the 43 synovial fluids. The levels of both stromelysin-1 and TIMP-1 were determined for each group and the concentration ratio of stromelysin-1/TIMP-1 in the synovial fluids of each group was highly correlated to the activation of progelatinase B.

CONCLUSION

The balance between the concentrations of stromelysin-1 and of TIMP-1 in the synovial fluid appears to determine whether the progelatinase B molecule causes conversion into the active form.

[Dispersal of pollen and the variation in number of patients prescribed medicine for allergies in Otaru]

The number of patients prescribed medicine for allergies increased in May and September. Therefore, we suspected that the cause for the increase was pollen. Many kinds of pollen occur in Otaru, such as alder in April, Japanese black pine, white birch, acacia, larch in May, oak in June, and mugwort in September. The total number of pollen count of white birch was about 9 times that of mugwort, but the total number of patients prescribed Celestamine in the season of white birch pollen was about 0.8 times that of mugwort pollen. These results seen in Otaru differed from those in neighboring Sapporo. The coefficient of the correlation of the number of mugwort and white birch pollen and those of patients prescribed Celestamine were r = 0.304 and r = 0.766, respectively. We believe that making available information on pollen is very useful to improve the quality of life of patients.

[Transmission of methicillin-resistant Staphylococcus aureus in a hospital for aged and chronically ill inpatients]

When we tested bacterial contamination in the linens of aged or chronically ill inpatients in a general hospital (114 beds), 11 out of 60 patients were found to have methicillin-resistant Staphylococcus aureus (MRSA). Two of these were MRSA infections. Furthermore, 6 patients mostly elderly and with chronic diseases, were newly infected with MRSA after this surveillance period. So as to clarify the transmission route of MRSA in the hospital, we classified 12 MRSA strains into 4 types by several criteria such as types of coagulase, enterotoxin, toxic-shock syndrome toxin, sensitivity to antibiotics, plasmid contents, and restriction endonuclease digestion patterns of chromosomal DNAs. At the same time, we followed up the movement of patients in wards and conditions of patient contact with medical staff in the hospital. The data obtained revealed a specific correlation between one of the MRSA strains and a doctor, suggesting a contribution from medical staff to the transmission of MRSA in the hospital. It is necessary, therefore, to practice more careful protection procedures against bacterial infection especially in hospitals for aged and chronically ill patients who are vulnerable to various infectious agents.

Comparison of the hydrolysis of the three types of natriuretic peptides by human kidney neutral endopeptidase 24.11

The degradation of 3 human natriuretic peptides by human kidney neutral endopeptidase 24.11 has been investigated. The studies revealed that hANP-28 and hCNP-22 are the preferred substrates, whereas hBNP-32 is not. The enzyme has been known to inactivate hANP-28 from cleavage at the Cys-Phe bond at the beginning of its ring structure. Analysis of the cleavage sites of each peptide indicated that the initial cleavage site of hCNP-22 is analogous to that of hANP-28. The Cys-Phe bond of hBNP-32 was insensitive to this enzymatic cleavage. We speculate that the stability of hBNP-32 may result from the insusceptibility of its Cys-Phe bond at the beginning of the ring structure.

Correlation between the appearance of gelatinases in the synovial fluid of patients with rheumatoid arthritis and polymorphonuclear elastase, stromelysin-1, and the tissue inhibitor of metalloproteinase-1

OBJECTIVE

To clarify whether gelatinases in the synovial fluid are related to rheumatoid arthritis (RA).

METHODS

Gelatinases in the synovial fluid of patients with RA were analyzed by gelatin zymography.

RESULTS

We classified patients into 3 distinct groups based on the gelatinases present. Although inactive gelatinase A was found in the synovial fluid of all patients with RA, the presence of gelatinase B varied: group I contained none, group II contained inactive gelatinase B, and group III contained active gelatinase B. The presence of gelatinase B was positively correlated with the polymorphonuclear (PMN) elastase content of the synovial fluid. Furthermore, the presence of activated gelatinase B correlated well with the stromelysin-1 content. Conversely, large amounts of the tissue inhibitor of metalloproteinase-1 (TIMP-1) were found in the synovial fluid of patients in group II.

CONCLUSION

The appearance and form of gelatinase B may reflect the inflammatory condition of patients with RA.

Characterization of gelatinases in human placenta

Matrix metalloproteinases were extracted from human placenta. Gelatin zymograms showed four bands with gelatinase activity. These four bands were detected at Mr 72,000, 92,000, 130,000, and 210,000 respectively. Reduced and alkylated samples were detected at Mr 72,000 and 92,000. Immunoblotting analysis showed that the enzymes of Mr 130,000 and 210,000 were derived from gelatinase B (EC 3.4.24.35). Also, reduced gelatinase was activated by 4-aminophenylmercuric acetate more readily than a nonreduced gelatinase. This indicates that human placental gelatinases are stabilized by the tissue inhibitor of metalloproteinases.

Aminopeptidases in human retroplacental sera: purification and characterization of two enzymes

Ten different maternal serum samples were analyzed for the hydrolysis of S-Bz-Cys-pNA (substrate for CAP) and Ala-pNA. The results showed clear differences in the activities in individual sera. Similar S-Bz-Cys-pNA hydrolysis activity was detected for all sera. However, Ala-pNA hydrolysis activity differed remarkably. Serum exhibiting low Ala-pNA hydrolysis activity contained only CAP, and that exhibiting high Ala-pNA hydrolyzing activity contained CAP and AAP. The two aminopeptidases were independently purified to a homogeneous state through the same purification procedures and some of their biochemical properties were compared. The enzymes were quite different with respect to molecular mass, the substrate specificities for some aminoacyl-pNA substrates, and the effects of inhibitors. Among various natural peptides tested for hydrolysis, the enzymes hydrolyzed Met-enkephalin most rapidly, but their modes of action were different. Furthermore, only CAP degraded oxytocin and AAP exhibited a high kinin-converting activity.

Human placental dipeptidyl aminopeptidase III: hydrolysis of enkephalins and its stimulation by cobaltous ion

The degradation of enkephalin and related peptides by highly purified dipeptidyl aminopeptidase III (EC 3.4.14.4) was studied. The enzyme releases the N-terminal dipeptide units from substrates greater in length than the tetrapeptide. The enzyme exhibits an optimum of pH 7.5, Km of 81 microM and Vmax of 0.043 mumole/min for Leu-enkephalin. Its activity was markedly stimulated by Co2+, with both the Km and Vmax being increased. Among the enkephalin-related peptides examined, des-Tyr1-Leu-enkephalin was the most rapidly hydrolyzed with Co2+, but only slight stimulation was observed with Co2+.

Purification and characterization of thiol aminopeptidase from the cytosolic fraction of human placenta

A thiol-dependent aminopeptidase was purified from the cytosolic fraction of human placenta. The purified enzyme consisted of a single polypeptide chain with a mol wt of 95,000. The enzyme was most active in the neutral region with Ala-pNA as substrate, and the activity was increased about 20-fold in the presence of some -SH compounds. The results of substrate specificity studies indicated that the enzyme hydrolyzes bonds involving the amino groups of neutral and basic amino acid residues. However, higher thiol-dependent activity was only detected with neutral ones. The enzyme was strongly inhibited by microbial aminopeptidase inhibitors, puromycin, o-phenanthroline, and sulfhydryl reactive-reagents. As to several naturally occurring peptides tested, the enzyme showed N-terminal Tyr-releasing activity toward enkephalins and kinin-converting activity.

Purification and characterization of a membrane-bound neutral endopeptidase from human placenta

A membrane-bound neutral endopeptidase which hydrolyzes Suc-(Ala)3-pNA to succinyl dialanine and Ala-pNA has been purified from human placenta. The enzyme was solubilized from membranes with DOC and papain, and was purified about 5000-fold by successive chromatographies on Sephadex G-200, DEAE-Sephacel, butyl-Toyopearl 650, and Sephacryl S-300. It was found to be homogeneous on SDS-polyacrylamide gel electrophoresis and to have a molecular weight of about 70,000. It was strongly inhibited by phosphoramidon, thiorphan, and metal-chelating agents, but was not affected by most other protease inhibitors. These findings indicate that it can be classified as a phosphoramidon-sensitive neutral endopeptidase. With biologically active peptides as substrates, the enzyme preferentially cleaved the bonds at the amino side of hydrophobic amino acid residues. The physiological significance of this enzyme is discussed with reference to the placental barrier.

Purification of a membrane-bound neutral endopeptidase from rat kidney and its activation by polyamines

An endopeptidase which cleaves succinyl trialanine p-nitroanilide (Suc(Ala)3-pNA) into succinyl dialanine and alanine p-nitroanilide (Ala-pNA) was solubilized from a microsomal membrane fraction of rat kidney with Nonidet P-40 following treatment with 1 M KCl and Brij 35. The solubilized enzyme was purified to homogeneity by DEAE-Sephadex chromatography, Sepharose CL-6B gel filtration and sucrose gradient centrifugation. The final enzyme preparation had a specific activity of 1.69 mumol/min/mg protein, representing about 140-fold purification over the starting membrane. The enzyme hydrolyzes Suc(Ala)3-pNA with a Km value of 0.28 mM and a Vmax value of 1.3 mumol/min. The molecular weight of the undenatured enzyme was estimated to be 360,000 by gel filtration on a Sepharose CL-6B column and that of the denatured enzyme to be 92,000 by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, revealing the presence of a single polypeptide chain. The enzyme was markedly activated by polyamines, producing increases in the values of both Km and Vmax. Comparatively less activation was found in the presence of some monovalent cations and Ca2+. The activation by polyamines was inversely proportional to the concentration of monovalent cations, but Ca2+ and polyamines seemed to stimulate additively.

Activated carbon beads for the removal of highly albumin-bound species

Activated carbon beads in which 5% activated carbon powder was embedded in 4% agarose were prepared by the emulsion technique. The column of the beads was demonstrated to effectively remove salicylic acid, warfarin, and long-chain fatty acids from solutions containing albumins by either zonal or frontal analysis under the condition of 0.1 M NaCl, pH 3.0 (HCl). The beads were also demonstrated to purify a commercial human serum albumin preparation from residual fatty acids. The beads would be of value in many biochemical purification processes in which activated carbon is employed.

Binding capacities of human serum albumin monomer and dimer by continuous frontal affinity chromatography

Human serum albumin monomer and dimer obtained by fractionation of a commercial preparation were immobilized on CH-Sepharose 4B by covalent coupling. For salicylic acid, warfarin, phenylbutazone, mefenamic acid, sulphamethizole and sulphonylureas, the binding capacities of the monomer and dimer were compared by continuous frontal affinity chromatography. The salicylate-binding capacities of both monomer and dimer were essentially retained upon immobilization. For these drugs, the dimer showed only about 10-30% less capacity per monomeric unit than that of the monomer, the reduction being associated for most drugs with the intrinsic binding constant rather than with the number of binding sites.

Mutual displacement interactions in the binding of two drugs to human serum albumin by frontal affinity chromatography

A continuous frontal analysis chromatographic method was developed for studying the simultaneous binding of two drugs or ligands with an immobilized macromolecule. The usefulness of this method was demonstrated in the interactions of sulphamethizole and salicylic acid with human serum albumin (HSA). The mutual inhibitory effect on the binding of one drug of the presence of the other was directly shown to be due to displacement of the bound drug from HSA by the other. On the basis of a double-reciprocal plot analysis, these two drugs are interpreted as competing for the same primary binding sites.