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Biomedical subjects

M Iwasa

Publications and source records attributed to M Iwasa.

At least 73 records · Page 4Linked to original sources
PubMed1991

Identification of fetal hemoglobin and simultaneous estimation of bloodstain age by high-performance liquid chromatography.

A method using reverse-phase high-performance liquid chromatography (HPLC) for the identification of fetal hemoglobin (Hb F) and the simultaneous estimation of bloodstain age is described. Umbilical cord and neonatal bloodstains can be differentiated from adult stains by the presence of gamma-globin chains which are characteristic of Hb F. With this method, cord and neonatal blood could be distinguished from adult blood in stains up to 32 weeks old. The age of the stain was estimated from the ratio of the peak area of the alpha-globin chain to that of heme on the same chromatogram. The ratio decreased gradually with an increase in the age of the stain up to 20 weeks old. Studies performed at each time period revealed no significant difference in the ratios of cord and neonatal bloodstains or in the ratios of cord and adult stains. The regression equation calculated from the ratios (y) and the ages of stains in weeks (x) expressed logarithmically is y = 2.5758-0.2497 In (x) and the coefficient of correlation is -0.7491 (n = 252, P less than 0.001). The present method, having the advantages of simplicity, speed and sensitivity, should be of great value to forensic science.

Adult↗
PubMed1991

Simultaneous observation of catecholamine, serotonin and their metabolites in incised skin wounds of guinea pig.

In order to examine the vital reaction in wounds, catecholamines, serotonin (5-HT) and their metabolites in the incised skin wounds of guinea pigs were analyzed simultaneously by high-performance liquid chromatography (HPLC) using electrochemical detection (ECD). The principal changes in the levels of these compounds in vital wounds were as follows: a considerable decrease in norepinephrine (NE) content was observed 12-24 h after injury which persisted to at least 7 days. 3,4-Dihydroxyphenylacetic acid (DOPAC) decreased slightly for up to 30 min and then showed no significant difference compared with postmortem levels. Epinephrine and dopamine were barely detected by the HPLC-ECD method employed. 5-HT concentrations which showed an increase up to 24 h showed maximum levels 800 microns from the wound edge at 10 and 30 min after injury. 5-Hydroxyindoleacetic acid (5-HIAA) was significantly higher than the postmortem level over almost the entire period of these experiments. A 5-HIAA content of at least twice the postmortem level was observed 800 microns from the wound edge of a 10-min-old vital wound. Therefore, 5-HIAA is a likely candidate as a new marker for evaluating the vital reaction in wounds. The vital characteristics of NE, DOPAC, 5-HIAA and 5-HT in 10-min-old wounds persisted for up to 12 h at room temperature after death. These results suggest that the HPLC-ECD method used here is very useful for simultaneous examination of the vital reaction in wounds from the earliest to the later stages of the wound-healing period.

Animals↗
PubMed1991

[Studies on tsutsugamushi disease in Gifu prefecture. 4. Survey results in Ena and Takayama City, and the summary of the studies in the prefecture].

Investigations of trombiculid mites and Rickettsia tsutsugamushi in wild rodents were made in Ena (Nov. 1988) and Takayama (May 1989) City. In the former area where no patient has been reported so far, Leptotrombidium pallidum (63.9%) was most predominant and no L. scutellare was found. A Karp-related rickettsia (11.1%) was isolated from wild rodents and 30% of them had antibody to R. tsutsugamushi (anti-Karp was prominent). The latter area where patients were reported in spring as well as in autumn, L. pallidum (22.4%) was one of the dominant species in spring. Karp-related strains were isolated from 37.5% of wild rodents. And the antibody possession rate was 50.0%. These data reconfirmed our hypothesis that the majority of patients in autumn were infected by L. scutellare and a part by L. pallidum. In spring in Takayama area, the vector was L. pallidum which possessed Karp-related strain(s).

Animals↗
PubMed1990

Experimental glycerol myopathy: a histological study.

Histopathological changes induced by the intramuscular injection of glycerol were studied in the muscle fibers of rabbits. Fifteen minutes after the injection of 1 ml of 50% (v/v) glycerol, hypercontraction of fibers, disruption of the plasma membrane, and invasion of lanthanum into the sarcoplasm were observed. Between 12 and 24 h after the injection, more extensive pathological changes were seen which included: variation in fiber size; degeneration and necrosis of muscle fibers; hypercontraction of fibers by light microscopy; disruption of the plasma membrane by electron microscopy; vacuolar changes; hypercontraction of myofibrils, and selective loss of Z-bands. Between 7 and 14 days after glycerol injection, extensive regenerative changes were seen. The degenerative changes were similar to those seen in muscle in Duchenne muscular dystrophy, suggesting that a similar mechanism may be involved in the two conditions, so that experimental glycerol myopathy could be a good model for pathophysiological studies on Duchenne muscular dystrophy.

Acid Phosphatase↗
PubMed1990

Species identification of blood and bloodstains by high-performance liquid chromatography.

A reverse-phase high-performance liquid chromatographic method for species identification of blood and bloodstains is described. The method employs a 300 A pore SynChropak RP-4 column and ternary solvents (acetonitrile-trifluoroacetic acid-water) and can not only identify a species by its characteristic chromatogram, but also simultaneously demonstrates that it is of blood origin by the existence of the heme peak. Deformations in chromatographic profiles obtained with older bloodstains were observed, but the retention times of heme and the major peaks showed only minor changes. The species could be identified from bloodstains at least 3 months old and the present method has the advantage of simplicity, speed and sensitivity in the practice of forensic science.

Adult↗
PubMed1990

A study on the vital reaction in wounded skin: simultaneous determination of histamine and polyamines in injured rat skin by high-performance liquid chromatography.

This paper describes a modified method of simultaneous quantitative determination of histamine and polyamines (putrescine, cadaverine, spermidine and spermine) in incised skin wounds of rats using high-performance liquid chromatography (HPLC) with a strong-cation exchange column, shim-pack ISC-05/S0504P, employing a linear gradient of 0.7-2.5 M sodium chloride. There was scarcely any change in the histamine content of the vital wounds throughout the one week experimental period, although content decreased slightly in 1-h-old wounds. On the other hand, concentrations of putrescine and spermidine increased suddenly 12 h after wounding, and spermine content increased slightly in 4-day-old wounds. There was no post-mortem change in the histamine, spermidine and spermine contents of vital wounds allowed to stand at 25 degrees C up to 24 h after death. Based on these results, this HPLC method may be useful for the determination of wound age during the period of healing.

Animals↗
PubMed1990

Trombiculid mites (Acari: Trombiculidae) and Rickettsia tsutsugamushi isolated from wild rodents in a new endemic area of Japan.

Investigations of trombiculid mites and Rickettsia tsutsugamushi in wild rodents were made in southern Gifu Prefecture where patients infected with tsutsugamushi disease recently have been found. A total of 16,396 trombiculid mites, consisting of 10 species from three genera, was collected from 170 Apodemus speciosus in two locations. Kani-Sakahogi and Kuze. Leptotrombidium scutellare (Nagayo et al.) (44.0%) was most predominant, followed by L. pallidum (Nagayo et al.) (26.9%); L. fuji (Kuwata et al.) (13.6%); and Gahrliepia saduski Womersley (14.2%). These four species constituted the bulk of the chigger mite fauna. L. scutellare was present from October to February with a remarkably high peak in November, whereas pallidum occurred from November to March with the highest peak in December. L. fuji and G. saduski showed their highest peaks in December and moderate peaks in early summer (April and May). Positive identification of Rickettsia tsutsugamushi in wild rodents from Kani-Sakahogi were found to be 50 and 58.3% in November 1985 and 1986, respectively, and 38.5% in November 1986 from Kuze. R. tsutsugamushi was isolated from chigger mites of an L. pallidum-rich group, displaying the highest titer to Karp strain. Serological investigation of rodents to R. tsutsugamushi antibodies were calculated as 41.6 and 50% positive in November 1985 and 1986 in Kani-Sakahogi, respectively, and 50% in November 1986 in Kuze. The Karp strain was dominant in specificity to antibodies. These results indicate that the surveyed areas have a high probability of occurrence of tsutsugamushi disease, and L. scutellare and L. pallidum may serve as the vectors in these areas. Particularly, we suggest that L. scutellare is the most important vector which has caused a recent outbreak of this disease in southern Gifu Prefecture.

Animals↗
PubMed1990

The calliphorid larvae parasitic on birds in Japan (Diptera: Calliphoridae).

The immature stages of Protocalliphora maruyamensis Kano et Shinonaga are newly described and the third instar larva of P. azurea (Fallén) is redescribed from specimens collected in Japan. The larval morphology of Protocalliphora is discussed. A key to the third instar larvae of Japanese bird-parasitic blowflies is given.

Animals↗
PubMed1989

Identification of fetal hemoglobin in blood stains by high performance liquid chromatography.

A new method for the identification of fetal hemoglobin (Hb F) in blood stains by reverse-phase high performance liquid chromatography is described. Differentiation between fetal and adult blood stains is based on the existence of gamma-chain peaks which are characteristics of Hb F. Very few gamma chains appeared on chromatograms of all the adult blood stains examined. The level of Hb F could be determined by measuring the total of chromatogram gamma-globin chain areas, and expressing it as a percentage of total Hb. Levels in six cord blood stains on filter paper ranged from 81.1% to 91.3% and remained constant for at least 12 weeks. This method is of great value for its simplicity, sensitivity and speed, and most importantly for its reliability in the field of forensic medicine.

Abortion, Illegal↗
PubMed1988

An application of a quantitative analytical system for the grading of pulmonary fat embolisms.

The severity of pulmonary fat embolism in 5 autopsied cases has been measured using a quantitative image analytical system. With reference to the mean size of the fat emboli, the cases were divided into 2 groupings regardless of the number of the emboli. The mean sizes of the emboli in 3 cases of the first group were significantly larger (about 490-600 microns 2) than those found in the 2 cases of the other group (about 220 and 235 microns 2). An investigation into the localization of fat emboli revealed that more were lodging in the small arteries and arterioles in the first group than in the second. Our results have indicated that a reliable grading of pulmonary fat embolism can not be established without a quantitative image analysis of the size and localization of the fat emboli, and that this quantitative analytical method is useful in achieving this reliable grading.

Adolescent↗