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Biomedical subjects

F Minagawa

Publications and source records attributed to F Minagawa.

At least 19 recordsLinked to original sources
PubMed1997

Epitope mapping of twelve monoclonal antibodies against the phenolic glycolipid-I of M. leprae.

Epitope mapping of 12 monoclonal antibodies (MAbs) directed to the trisaccharide part of the phenolic glycolipid-I (PGL-I) of Mycobacterium leprae was carried out by using the set of chemically synthesized sugar-BSA conjugates. The results can be summarized as follows: mAb (1-21), mAb (1-24) and mAb (1-25) recognized the outer (nonreducing end) monosaccharide of the trisaccharide chain of PGL-I. However, the affinity of these MAbs to the outer monosaccharide was weak. They required the contributions of some parts of the second sugar for enough affinity. MAbs ml 6A12, ml 8A2, ml 8B2, and PG2 B8F recognized the outer disaccharide. MAb F47-21-3 recognized the outer disaccharide and some parts of the third sugar. MAb SF 1 recognized the trisaccharide of PGL-I. MAb 3D1-A9 recognized the phenol group and the structure around the branching point on the carrier protein in addition to the trisaccharide. MAbs DZ 1 and 2G3-A8 had unique characters which recognized the inner part of the sugar chain. MAb DZ 1 recognized the inner (reducing end) disaccharide. MAb 2G3-A8 recognized the inner monosaccharide, phenol group and the structure around the branching point on the carrier protein. All of the MAbs tested, except for ml 6A12, recognized the anomeric configurations in the sugar parts they recognized; ml 6A12 recognized the anomeric configuration only within the outer disaccharide. This set of MAbs, which were well defined on their binding specificity, promises to be an effective tool for the immunological study of PGL-I and the clinical assessment of leprosy.

Antibodies, Bacterial↗
PubMed1994

Down regulation of Ia expression in macrophages following incubation with mycobacteria.

Macrophages are known to release cytokines in response to various kinds of stimulators. In the present study, peritoneal macrophages from C3H/He or C3H/HeJ mice were incubated in vitro with heat-killed M. lepraemurium, M. intracellulare or M. gordonare for 3 days followed by harvest culture supernatant to analyze cytokine activities. It, therefore, seems that macrophages phagocytizing these mycobacteria, released interleukin-1 (IL-1) and tumor necrosis factor (TNF) in culture media. The amount of release was dose dependent on mycobacteria employed. In addition, macrophages, as already have reported elsewhere, treated with IFN for 2 to 3 days showed enhanced expression of surface Ia; although the expression was inhibited if the cells phagocytized mycobacteria. Similarly, the reduced expression of Ia was observed in peritoneal macrophages from MRL/lpr mice after 3 day-culture with mycobacteria in vitro. More importantly, in the presence of the supernatant obtained from macrophages incubated with mycobacteria, IFN gamma-treated normal macrophages exhibited suppressed expression of Ia. These results demonstrate that cytokine release and reduced expression of surface Ia in macrophages are simultaneous phenomena after phagocytosis of mycobacteria. Suppression of Ia may be in part induced by Ia suppressive factor(s) released from mycobacterium-phagocytized macrophages.

Animals↗
PubMed1994

Clofazimine-mediated augmentation of LPS-induced tumor necrosis factor production in macrophages.

Tumor necrosis factor (TNF) exerts multiple biological activities including immune response. It is also believed to play an important role in anti-bacterial response. In this study in vitro, we observed augmentation of LPS-induced TNF production from mouse macrophages by clofazimine treatment. Rifampicin, however, did not indicate such an activity. Clofazimine itself, on the other hand, did not have any TNF-inducing activity. Clofazimine is a well known anti-leprosy drug; in addition, from the results obtained here, this drug could induce anti-M. leprae response of host by way of the augmented immune response by enhanced cytokine production from macrophages.

Animals↗
PubMed1993

Assessment of autonomic nervous activity by heart rate spectral analysis in patients with variant angina.

The purpose of this study was to assess the role of the autonomic nervous system in the pathogenesis of coronary artery spasm in patients with variant angina. We evaluated cardiac sympathetic and parasympathetic activity from the power (logarithmic scale) of the low-frequency (approximately 0.04 to 0.12 Hz) and the high-frequency (approximately 0.22 to 0.32 Hz) spectral components of heart rate variability with Holter monitoring in seven patients with nocturnal variant angina and in 11 healthy men who served as control subjects. None of the patients had organic coronary artery stenosis as determined by angiography. Low-frequency and high-frequency logarithmic values were calculated for each 5-minute period from 30 minutes before to immediately before each angina attack. The logarithmic low-frequency value during the 5-to-0-minute period was greater than the low-frequency values during most of the other periods (p < 0.05 - p < 0.01). The logarithmic high-frequency values during the 10-to-5-minute and 5-to-0-minute periods were greater than those during the 30-to-25-minute period (p < 0.05 and p < 0.01, respectively). These data indicate that parasympathetic activity increased during the 10 minutes before attacks of nocturnal variant angina, whereas sympathetic activity with vagal modulation increased during the 5 minutes before such attacks. The same pattern of changes in heart rate variability was found in the absence of ST-segment elevation in patients and in control subjects. So this phenomenon was not just associated with coronary spasm and variant angina. It is suggested that circadian variation in disease activity is also associated with spontaneous attacks.

Adult↗
PubMed1984

Salivary immunoglobulins and antibody activities in leprosy.

The technics of immunodiffusion and the fluorescent leprosy antibody absorption (FLA-ABS) test were used to determine the levels of immunoglobulins and their antibody activities against Mycobacterium leprae in the serum and the saliva collected from a total of 110 patients with leprosy (50 lepromatous, 24 borderline, and 36 tuberculoid). The average levels of serum IgG, IgM, and IgA were not significantly different among these patients. In saliva, however, IgM was detected in only two cases with lepromatous leprosy and three tuberculoid cases. Salivary IgG and IgA levels and their ratios to those in the sera were not significantly different according to the classification of leprosy. The percentages of positive FLA-ABS tests in the sera and saliva were compared by using fluorescent antibodies specific for IgG, IgM, and IgA, respectively. The results indicated that M. leprae-specific antibodies in the serum were mainly found in IgG and IgM and, less frequently, in IgA. IgG antibodies were found more frequently in lepromatous and borderline patients than in tuberculoid cases. On the other hand, salivary IgA antibodies against M. leprae were found in a significant number of specimens; whereas IgG and IgM antibodies were scarcely found. However, the percentage of positive FLA-ABS tests caused by salivary IgA antibodies was higher in the patients with tuberculoid or borderline leprosy than in those with lepromatous leprosy. A significant number of patients with tuberculoid or borderline leprosy secreted M. leprae-specific IgA antibodies into saliva without detection of circulating IgA antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1980

Foot pad enlargement as a measure of induced immunity to Mycobacterium leprae.

Foot pad enlargement (FPE) has been used as a measure of induced immunity to M. leprae, FPE peaked at 2-3 days, but it sometimes persisted for 4 weeks or more. Both as the inducing and eliciting antigen, heat-killed M. leprae were effective, and the optimum dose was about 1 x 10(7) bacilli. Higher doses were associated with flattening of the dose-response curve. Disrupted bacilli were not effective in immunizing mice, but they elicited FPE responses in mice immunized with intact bacilli. Cord factor was not found to have adjuvant activity for M. leprae. In immunization, the intradermal route was confirmed to be more effective than the foot pad route; the subcutaneous route was effective in providing protection against infection. FPE tests were used to investigate the steps of standard purification procedures for M. leprae in armadillo livers. A trypsin-chymotrypsin digestion step was found to be harmful to immunogenicity in one of two experiments.

Animals↗
PubMedDate not supplied

Power spectral analysis of heart rate and arterial blood pressure oscillation in brain-dead patients.

To clarify the mechanism of the slow arterial blood pressure oscillation seen in brain-dead patients, we investigated the frequency of fluctuations in arterial blood pressure and heart rate using power spectral analysis. The electrocardiogram, arterial blood pressure and respiration were recorded simultaneously from 9 brain-dead patients and 8 vegetative patients. Power spectral analysis of these data revealed a very slow fluctuation (0.002-0.01 Hz) in arterial blood pressure in brain-dead patients, the frequency of which was equal to that of the low-frequency spectrum of heart rate, indicating vasomotor sympathetic activity. Neuropathological examinations of the medulla and spinal cords of 4 autopsied brain-dead patients revealed that the spinal cord, ventral and dorsal nerve roots, and the nucleus intermediolateralis of the lateral horn below the level of C3/4 were virtually intact. These findings suggest strongly that the slow oscillation of arterial blood pressure in brain-dead patients originates from the vasomotor tone controlled by spinal sympathetic nerves.

Adolescent↗