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Biomedical subjects

N Yamawaki

Publications and source records attributed to N Yamawaki.

17 recordsLinked to original sources
PubMed2004

Vitamin K concentrations in the maternal milk of Japanese women.

AIM: To determine the concentration of vitamin K including K1 (phylloquinone) and K2 (menaquinone-n; MK-n) in the maternal milk of Japanese women. METHODS: We collected human milk samples from more than 4000 mothers living throughout Japan from December 1998 to September 1999, and analysed the contents of vitamin K1 and K2 in 834 of the samples. We defined as group A the 555 samples among them that met the following conditions: breast milk of mothers who were under 40 y old, not in the habit of smoking and/or using vitamin supplements, and whose babies showed no symptoms of atopy and whose birthweights were 2.5 kg or more. Vitamins extracted from the enzymatic hydrolysates of the human milk were purified with a Sep-Pak Plus silica cartridge, and then measured by a method based on high-performance liquid chromatography (HPLC) combined with coulometric reduction and fluorometric detection. RESULTS: The mean concentration of vitamin K (K1 + K2) of mothers of group A and all groups were 0.434 +/- 0.293 and 0.517 +/- 1.521 microg/100 ml (average +/- SD), respectively, and menaquinones containing 4, 6 and 7 isoprenoid residues could be detected in the milk samples. Vitamins K1 and MK-4 were found to be predominant in the milk samples, and the concentration of MK-4 in colostrum was higher than that of MK-4 in mature milk. We also found that the MK-7 concentration in the milk of mothers living in eastern Japan was higher than that of mothers living in western Japan. CONCLUSION: The different features of vitamin K1 and MK-7 concentrations in the milk of Japanese women may be due to differences in dietary foods.

Adult↗
PubMed2000

Pilsicainide for conversion and maintenance of sinus rhythm in chronic atrial fibrillation: a placebo-controlled, multicenter study.

BACKGROUND: Pilsicainide is a newly synthesized antiarrhythmic agent with class Ic properties. Various antiarrhythmic agents have been used to convert atrial fibrillation (AF) to sinus rhythm or decrease the rate of relapse of AF. METHODS: We randomly assigned 62 patients with chronic AF to oral treatment of either a placebo (10 patients) or 150 mg/day of pilsicainide (52 patients) for 4 weeks before electrical cardioversion. Before oral administration of pilsicainide, 41 patients underwent transesophageal echocardiography to investigate whether there was thrombus formation in the heart chambers. Patients without pharmacologic defibrillation underwent direct current cardioversion to restore sinus rhythm. After successful cardioversion, all patients continued to receive pilsicainide and were monitored for up to 2 years. RESULTS: Before cardioversion, 11 patients in the pilsicainide group (21%) reverted to sinus rhythm. No patients in the placebo group reverted to sinus rhythm. Direct current cardioversion was performed in 51 patients; however, 8 patients were not converted to sinus rhythm (5 patients receiving pilsicainide, 3 patients receiving placebo), and 3 patients needed intracardiac cardioversion to convert to sinus rhythm. Asymptomatic bradyarrhythmias were observed in 5 patients in the pilsicainide group. During the follow-up period, 33 patients (71%) in the pilsicainide group remained in sinus rhythm at 1 month; this number decreased to 23 patients (49%) at 3 months, 20 (43%) at 6 months, 16 (34%) at 12 months, 16 (34%) at 18 months, and 16 (34%) at 24 months. All patients receiving placebo continued to receive placebo after the cardioversion, and AF recurred a few days after cardioversion in all cases. No independent discriminant variables were identified in the groups between maintenance and nonmaintenance of sinus rhythm. Although no serious side effects regarding pilsicainide have been documented, one patient died of acute myocardial infarction, most likely not related to pilsicainide administration. CONCLUSIONS: Pilsicainide is effective in restoring or maintaining sinus rhythm in patients with chronic AF lasting longer than an average duration of 22 months. No major adverse effects were observed.

Administration, Oral↗
PubMed1998

Leukocytapheresis therapy by extracorporeal circulation using a leukocyte removal filter.

Leukocytapheresis therapy has been used to try to treat such intractable diseases as autoimmune and neurologic diseases, achieving good results. However, a number of problems have been identified in leukocyte removal by thoracic duct drainage or continuous centrifugal separation; namely the high risk, expensive cost, and complicated operation. Asahi Medical Co. has developed an innovative solution for such conventional problems. Its new leukocyte removal filter (Cellsorba) is capable of removing white blood cells by perfusion of whole blood by means of simple extracorporeal circulation. Leukocytapheresis therapy using the Cellsorba column is being confirmed as extremely effective for many inflammatory diseases, as well as in autoimmune and neurologic diseases. This paper outlines information about the Cellsorba column and introduces several reports on therapeutic results.

Autoimmune Diseases↗
PubMed1998

A new device for selective removal of CD4+ T cells.

To control antigen (Ag)-specific immune cells is important in the treatment of autoimmune diseases. In particular, a direct solution may be obtained by controlling the CD4+ cell function that controls the immune response of autoimmune T cells. Thus, a technique to selectively remove CD4+ cells has been developed, based on the consideration that the immune system may possibly be modified by selectively removing the CD4+ cells by means of extracorporeal circulation. The currently developed device to selectively remove CD4+ cells uses a material made of nonwoven fabric with monoclonal antibodies immobilized on the surface. With this device, removal of only CD4+ cells from human mononuclear cells suspension can be accomplished. Moreover, CD4+ cells can be specifically removed from peripheral whole blood by direct perfusion. This review outlines a series of procedures for selective cell removal and the results of our research.

Animals↗
PubMed1998

Immusorba TR and Immusorba PH: basics of design and features of functions.

Immusorba was reported by Yamazaki et al. to be the world's first practical immunoadsorbent in 1982. Since then, this immunoadsorbent has accumulated an abundance of clinical achievements. Immusorba has such unique functions that it is used in treating various diseases and holds possibilities for application to more diseases. Immusorba was designed as an artificial receptor for rheumatoid factor (RF) based on structural analysis of heat-denaturated globulin. Subsequently, new substances that it can adsorb have been found as seen in reports on the adsorption performance of Immusorba to anti-acetylcholine receptor antibodies (anti-AChR Abs) and antiganglioside antibodies. Along with this, Immusorba has been used in treating a wide range of diseases. The greatest characteristic of Immusorba is that its adsorption capability is selective rather than specific, making it effective against a great number of diseases.

Acetylcholine↗
PubMed1998

A selective transthyretin-adsorption column for the treatment of patients with familial amyloid polyneuropathy.

A transthyretin (TTR)-adsorption column has been developed for the removal of variant TTR from the plasma of patients with familial amyloid polyneuropathy (FAP). The adsorbent is an ion-exchange resin made of porous beads of polyvinyl alcohol gel covalently bound with dimethylaminoethanol. This column was used for three patients with type I FAP. It reduced the concentrations of both normal and variant TTR in the plasma to about half of their pre-adsorption levels. Except for thyroxine, retinol-binding protein and IgM, other proteins in serum were not significantly decreased and there were no adverse effects in long term clinical usage of this TTR-adsorption column. In this trial, we did not obtain concrete evidence that TTR-adsorption therapy can stop or delay the progression of the disease in a FAP patient. However, if we are able to apply this technique more frequently and effectively, TTR-adsorption therapy using our column might be useful for the treatment of FAP patients.

Adsorption↗
PubMed1997

Treatment of experimental allergic encephalomyelitis by selective removal of CD4+ T cells.

Experimental allergic encephalomyelitis (EAE) is a major animal model of human multiple sclerosis (MS). The pathogenesis of both MS and EAE directly involves CD4+ helper T cells. To remove CD4+ T cells selectively from the circulation, we designed a new column in which anti-CD4 monoclonal antibody was immobilized on the activated substance. Most of the CD4+ T cells, including pathogenic T cells, were selectively adsorbed from whole blood with a direct perfusion through the column in vitro, resulting in depletion of the antigen-specific T cell responses. A preliminary trial of ex vivo treatment with the column in EAE rats lowered the percentages of CD4+ populations but failed to alter the course of the disease, suggesting repeated treatment would be necessary to suppress the development of the disease. We conclude that this new column is potentially useful, and repeated treatment would be beneficial in MS and other CD4+ T cell dependent autoimmune diseases.

Animals↗
PubMed1989

Extracorporeal immunoadsorption with IM-PH or IM-TR column.

In order to selectively remove pathogenic macromolecular reactants, a biological affinity type adsorbent (a DNA colloidin charcoal column or protein A sepharose CL4B = Prosorba) has been developed and used for the treatment of immune disorders, alloimmunization and cancer. However, because physiologically active materials are required in this procedure, it is difficult to ensure an adequate supply of raw materials (and their handling, sterilization and preservation as an immunoadsorbent. To overcome the above-mentioned problems, we developed physicochemical type immunoadsorbents IM-TR and IM-PH, which consist of polyvinyl alcohol gel where tryptophan, in the former, and phenylalanine, in the latter, is used as a ligand. IM-PH has a better selectivity than IM-TR, however, IM-TR is a more efficient adsorbent of anti-acethylcholine receptor antibody than IM-PH. IM-PH plasma perfusion has been successfully used with patients with rheumatoid arthritis, systemic lupus erythematosus (SLE), and multiple sclerosis (MS).

Animals↗
PubMed1987

In vitro investigations with selective adsorbents for IgE and IgM.

In vitro studies were carried out with IM-T. This adsorbent consists of polyvinyl alcohol joined with tryptophan side chains and was delivered by ASAHI Medical Co., Ltd., Tokyo/Japan. It was found that IM-T binds immunoglobulins G and M and also immune complexes only moderately but IgE was adsorbed in remarkable amounts. A clear dose-dependent was adsorbed in remarkable amounts. A clear dose-dependent manner of the IgE adsorption could be stated. Kinetic studies revealed that the binding was only slow and gradual.

Animals↗
PubMedDate not supplied

In vitro studies with selectively lipid adsorbing materials.

A new synthetic material was developed by ASAHI Chemical Industry Co., Ltd., Tokyo, Japan. In vitro studies revealed selective bindings of cholesterol, LDL (low density lipids) and beta-lipoprotein by this material. Maximal bindings were reached within 1 min, and therefore, the affinities of the LDL-adsorbent to these lipid components seem to be high. In contrast to these results the plasma values of HDL (high density lipids) and apoprotein A remained nearly unchanged. Triglycerides were removed only moderately. Investigations about lipid removing capacity of the new material with the plasma of patient with familiar hypercholesterolemia and studies about interactions with the complement system were also promising. Synthetic materials which are under development in G.D.R. showed similar lipid binding capacities.

Acrylic Resins↗