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Biomedical subjects

Y Hashiguchi

Publications and source records attributed to Y Hashiguchi.

At least 73 records · Page 4Linked to original sources
PubMed1993

Molecular karyotype characterization of Leishmania panamensis, Leishmania mexicana, and Leishmania major-like parasites: agents of cutaneous leishmaniasis in Ecuador.

Molecular karyotypes of Leishmania isolates from patients with cutaneous leishmaniasis in Ecuador were analyzed by pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization. The DNA karyotypes of L. major-like parasites were similar between two human isolates from a lowland coastal and a highland Andean region, but were apparently different from those of eleven World Health Organization reference strains including L. major. The smallest chromosome of 240 kilobases in L. major-like parasites was found to belong to the 715-class of small linear chromosomal DNAs, which have been shown to appear in some lines of Leishmania. Chromosome banding patterns of L. mexicana isolates exhibited a novel, ordered, chromosomal ladder, and were identical among four human isolates and one canine isolate from a restricted geographic region in the Andes. On the other hand, minor chromosome size polymorphisms were observed among three L. panamensis isolates from different endemic regions near the Pacific Coast. Chromosomal locations of dihydrofolate reductase-thymidylate synthetase and P-glycoprotein genes revealed further differences in chromosomal organizations among these Leishmania species in Ecuador. These results indicate that karyotype analysis by PFGE is useful for epidemiologic studies of leishmaniasis in Ecuador.

Animals↗
PubMed1992

Phlebotomine sandfly species in Paraguay and their infection with Leishmania.

Nine species of sandflies, Lutzomyia (Nyssomyia) whitmani (Antunes and Countinho), Lutzomyia (Nyssomyia) intermedia (Lutz and Neiva), Lutzomyia (Psathyromyia) shannoni (Dyar), Lutzomyia migonei (Franca), Lutzomyia (Pintomyia) fischeri (Pinto), Lutzomyia (Pintomyia) pessoai (Countinho and Barretto), Lutzomyia cortelezzii (Brethes), Lutzomyia walkeri (Newstead) and Lutzomyia (Trichopygomyia) longispinus (Mangabeira), were caught, by human bait and Shannon trap, in four areas of Paraguay hyper-endemic for human leishmaniasis. Lutzomyia whitmani and L. intermedia were the predominant species. All the species collected were found to be anthropophilic. Hindgut infections with leishmanial promastigotes were observed in only one (0.38%) of the 266 L. whitmani dissected. No L. intermedia were found infected, giving an overall infection rate of one (0.16%) of 615 flies dissected. The results indicate a very low rate of natural infection in endemic areas of Paraguay.

Animals↗
PubMed1992

Effects of a new dihydropyridine derivative, FRC-8653, on blood pressure in conscious spontaneously hypertensive rats.

Antihypertensive effects of FRC-8653, a new 1,4-dihydropyridine derivative, and its combined effects with an angiotensin converting enzyme (ACE) inhibitor, a diuretic, and a beta-adrenergic blocking agent were examined in conscious spontaneously hypertensive rats (SHR). When administered intravenously to SHR (10, 30 micrograms/kg), FRC-8653 lowered blood pressure more slowly and sustained it longer than nifedipine and nicardipine. Consecutive once-daily administrations of FRC-8653 to SHR (3 mg/kg, p.o.) produced a stable reduction of blood pressure throughout the experimental period of 29 d. When blood pressure was continuously measured for 24 h in conscious unrestricted SHR, orally administered FRC-8653 produced a long-lasting reduction in blood pressure. When concomitantly used with atenolol (30 mg/kg, p.o.), the antihypertensive effect of FRC-8653 was augmented in both potency and duration. However, simultaneous administration of captopril (30 mg/kg, p.o.) or hydrochlorothiazide (2.5 mg/kg, p.o.) did not modify the antihypertensive effect of FRC-8653.

Animals↗
PubMed1992

In vitro and ex vivo Ca-antagonistic effect of 2-methoxyethyl(E)-3-phenyl-2-propen-1-yl(+/-)-1,4-dihydro-2,6-dimethyl- 4-(3- nitrophenyl)pyridine-3,5-dicarboxylate (FRC-8653), a new dihydropyridine derivative.

The characteristics of calcium antagonism and vascular effect of 2-methoxyethyl(E)-3-phenyl-2-propen-1-yl(+/-)-1,4-dihydro-2,6-dime thyl-4-(3- nitrophenyl)pyridine-3,5-dicarboxylate (FRC-8653) were investigated. FRC-8653 inhibited an increase in intracellular free calcium concentration during membrane depolarization in PC12 cells. FRC-8653 also inhibited the specific binding of 3H-nitrendipine to cardiac membranes, in a similar manner to nifedipine and nicardipine. FRC-8653 inhibited KCl- and CaCl-induced contractions in isolated rabbit aorta, but failed to affect norepinephrine-induced contraction. The vasorelaxing effect of FRC-8653 in rabbit aorta developed more slowly than those of nifedipine and nicardipine. In ex vivo experiment, the inhibitory effect of orally administered FRC-8653 against KCl-contraction in rat aorta lasted longer than that of nifedipine. These findings suggest that FRC-8653 dilates blood vessels by blocking calcium influx via dihydropyridine-sensitive, voltage-dependent calcium channels and that the vascular effects are slow in development and long in duration.

Animals↗
PubMed1992

Spectroscopic quantitative analysis of blood glucose by Fourier transform infrared spectroscopy with an attenuated total reflection prism.

As an alternative way of long-term glycemic monitoring, the glucose measurement by analyzing Fourier transform infrared absorbance spectra with an attenuated total reflection prism has been developed. In glucose aqueous solution, glucose has characteristic absorptions at the wave numbers of 1033 and 1080 cm-1 and the absorption intensities are proportional to glucose concentrations. In serum and whole blood samples, however, red blood cell corpuscles, serum albumin and serum gamma-globulin interfere with the absorbance spectra of glucose and shift the base line upward significantly. Therefore, to eliminate these interferences in serum and whole blood samples, the feasibility of the calibration curves obtained by using difference absorbance spectra with those of fasting samples was studied. As a result, highly significant correlations between glucose concentrations estimated by Fourier transform infrared spectroscopic method and those measured by glucose oxidase method were obtained (r = 0.981 and 0.989 for serum and whole blood samples, respectively). From these experiments, it was concluded that by infrared spectroscopy glucose concentrations in the serum and whole blood samples could be measured quantitatively or monitored if the base line drifts and interferences were subtracted.

Blood Glucose↗
PubMed1991

Monthly variation in natural infection of the sandfly Lutzomyia ayacuchensis with Leishmania mexicana in an endemic focus in the Ecuadorian Andes.

In order to collect information on the role of Lutzomyia ayacuchensis in the transmission of leishmaniasis in a newly discovered Andean endemic focus in Ecuador, a longitudinal field study was carried out over 13 months. Monthly dissections were made of a minimum of 200 anthropophilic sandflies, collected at night during the month. A total of 2600 flies was separated from a small number of Lu. osornoi, another anthropophilic species in the area, and dissected; 95 (3.65%) were naturally infected with Leishmania mexicana promastigotes. The parasites were always located in the sandfly midgut. The current study revealed a marked monthly variation both in natural infections with Leishmania and in biting activity of sandflies in the endemic area, demonstrating a high transmission rate during the period from the early rainy season to the early or mid dry season (February to July).

Animals↗
PubMed1991

Experimental lethal infection of Leptospira interrogans in mice treated with cyclophosphamide.

After preadministration of cyclophosphamide (300 mg/kg), BALB/c mice were lethally infected with Leptospira interrogans serovar lai and a virulent strain of Leptospira interrogans serovar copenhageni, and leptospiral cells were detected in both kidneys of infected mice by indirect immunofluorescent assay. Nonpathogenic leptospirae, Leptospira biflexa serovar patoc, Leptonema illini, and an avirulent strain of L. interrogans serovar copenhageni, were not parasitic to the mice treated with cyclophosphamide. The cyclophosphamide-treated mice were protected from the homologous leptospiral infection by passive immunization with anti-leptospiral monoclonal antibody or with rabbit antiserum and by active immunization with lyophilized organisms or with protective antigen. The results of active immunization in mice treated with cyclophosphamide agreed well with those in nontreated hamsters, which were sensitive to the organisms. Furthermore, these experiments were reproducible with any lot of cyclophosphamide used. These results indicated that cyclophosphamide-treated mice can be used in the experimental infection of Leptospira in place of hamsters or guinea pigs.

Animals↗
PubMed1991

Andean leishmaniasis in Ecuador caused by infection with Leishmania mexicana and L. major-like parasites.

Between 1986 and 1988, epidemiologic studies were carried out in a small rural community in an Andean region of Ecuador, where cutaneous leishmaniasis is highly endemic. A total of 25 human cases, positive for Leishmania parasites by culture and/or smear, were examined. Fourteen of the cases were in infants less than one year of age, suggesting intradomiciliary transmission of the disease. Clinically, many of these cases were similar to descriptions of "uta," a form of cutaneous leishmaniasis which occurs in Andean regions of Peru and is reported caused by L. peruviana. Of the 11 positive cultures obtained from human cases in the present study, eight were identified by molecular characterization as L. mexicana and three were identified as L. major-like. Two additional isolates of L. mexicana were also made from an infected dog and from a sand fly, Lutzomyia ayacuchensis, living in the region, thus implicating the latter species as possible reservoir and vector, respectively, of L. mexicana in this highland community. The significance and validity of recent isolates of L. major-like parasites from the New World are also discussed.

Animals↗
PubMed1991

An artificial endocrine pancreas--problems awaiting solution for long-term clinical applications of a glucose sensor.

The artificial endocrine pancreas is a feedback controlled system regulating insulin delivery on a minute-by-minute basis according to measured blood glucose levels. The bedside-type artificial endocrine pancreas has been proven to be useful not only as a therapeutic tool for diabetic patients but also as an elegant research tool for investigating the pathophysiology of the disease. Recently, a wearable-type, closed-loop system has been developed, of which the breakthrough was the establishment of a needle-type glucose sensor. However, for the long-term clinical use of needle-type glucose sensors, several obstacles remain to be solved, such as oxygen dependency, biocompatibility of the membrane, etc. The most promising method for the non-invasive determination of blood glucose is infrared spectroscopy. The trend in the development of a closed-loop glycemic control system which enables perfectly physiological glycemic regulation on a long-term basis is directed to an implantable device. Much research is being conducted to realize such devices.

Alginates↗
PubMed1991

A review of leishmaniasis in Ecuador.

This article briefly reviews current knowledge about leishmaniasis in Ecuador--proceeding from 1920, when the first human case was described, to the present. Regarding basic conditions, it appears that 14 of Ecuador's 20 provinces have endemic leishmaniasis. Nationally, over 4,000 cases were registered in the 1983-1986 period. Of 260 cases cited in the literature from 1920 through 1987, 240 (92.3%) were said to involve cutaneous forms of the disease and 18 (6.9%) mucocutaneous ones. Only one case each of visceral and diffuse cutaneous leishmaniasis was reported in 1920-1987, and neither of these has been confirmed. Various Leishmania strains isolated by the authors from wild animals and man are currently being studied. To date, tests employing isoenzyme electrophoresis and monoclonal antibodies have identified some of the isolated strains as L. amazonensis and L. panamensis. At present it seems evident that a detailed study of leishmaniasis transmission in Ecuador is needed in order to develop a plan for future control of the disease. Survey work directed at identifying the particular Leishmania varieties prevalent in the country's different endemic areas is also needed, as is research on the sandfly vectors and animal reservoirs of the disease.

Animals↗
PubMed1990

Immunological reactivity and passive protective activity of monoclonal antibodies against protective antigen (PAg) of Leptospira interrogans serovar lai.

Monoclonal antibody (MAb) AG1 against the protective antigen (PAg) was produced and characterized. It had been extracted from Leptospira interrogans serovar lai by the chloroform-methanol-water method and was of glycolipid nature (23-30Kd). The fact that the PAg was a serogroup-specific antigen was shown by MAb AG1, because MAb AG1 agglutinated serovars of serogroup Icterohaemorrhagiae. Purified MAb LW2 and LW3 which are agglutinating antibodies of serovar lai and AG1 passively protected hamsters from leptospiral infection. Induction of the reactive oxygen intermediates by MAbs from peritoneal exudate macrophages of mice were observed in the chemical luminescence assay and the MAbs reacted with the PAg in the dot enzyme-linked immunosorbent assay. However, MAb LW4a against the genus-specific antigen present in the sub-surface of leptospiral cells did not show protective and reactive-oxygen-inducing activities; they reacted with the non-protective glycolipid antigen of low molecular weight (Fr I, 10-15Kd) in the dot enzyme-linked immunosorbent assay. These results indicated that anti-PAg antibody exhibited opsonic activity against Leptospira and the production of reactive oxygens by macrophages led to leptospiricidal action as one of the defence mechanisms of the host against leptospiral infection. However, the antibody against the genus-specific glycolipid antigen may not be important for protection against leptospiral infection.

Agglutination Tests↗
PubMed1989

Further studies on the effect of cyclosporin A on the course of Paragonimus infection in rats.

Paragonimus ohirai-infected rats were treated with cyclosporin A (CyA) at different times during the course of infection. CyA (5 x 80 mg/kg) affected the worm recovery, growth and maturation rates of P. ohirai with respect to control values. This tendency was most remarkable in animals treated 15 days and more after infection with CyA (groups B, +15 to +19 days; C, +25 to +29; D, +35 to +39 and E, +45 to +49). In group A (0 to +4), however, the drug did not affect markedly the growth and maturation of worms, although it significantly lowered worm recovery rates. CyA administration also affected normal migration of P. ohirai in the highly susceptible host (rat), when the drug was administered during the peritoneal and/or liver phase of infection. Thus, in this P. ohirai/rat model, CyA significantly reduced worm recovery rates, and affected the growth, maturation and migration of the worms depending on the time of administration.

Animals↗
PubMed1989

Identification, using isoenzyme electrophoresis and monoclonal antibodies, of Leishmania isolated from humans and wild animals of Ecuador.

Six strains of Leishmania isolated from wild mammals and humans on the Pacific Coast of Ecuador were identified by isoenzyme electrophoresis and by their reactivity patterns to a cross-panel of specific monoclonal antibodies using a radioimmune binding assay. Single isolates from Sciurus vulgaris, Potos flavus, and Tamandua tetradactyla were identified as Leishmania amazonensis. Three other strains, isolated from cutaneous lesions of humans, were identified as Leishmania panamensis.

Animals↗
PubMed1989

[A case of bilateral impaction of the lower second molars].

A case of bilateral impaction of the lower second molars is presented. A 15-year-old boy with an ill feeling at the right lower first molar was referred to us. X-ray examination revealed bilateral impaction of the lower second molars and the presence of bilateral teeth that seemed to be the unerupted third molars distal to the impacted second molars. Furthermore, a radiolucency approximately 3 X 3 mm in size was detected in the mesioapical region of the right lower first molar. These impactions were managed under local anesthesia by extraction of the right lower first molar and fenestration of the right lower second molar. After approximately 4.5 months, the right lower third molar was extracted. It was further followed approximately 1 month later by extraction of the left lower third molar and ipsilateral fenestration of the lower second molar. As a result, the right lower second molar erupted but it was considerably inclined in a mesial direction. The left lower second molar erupted normally almost up to the occlusal plane. In the absence of systemic abnormality, facial trauma, and maldevelopment of the jaw, impaction seemed to have been closely associated with some unknown local factor.

Adolescent↗
PubMed1989

[Plastic operation of alveolar process by visor osteotomy].

Extraction of teeth from the lower jaw often results in atrophy of the alveolar process and mandibular body, and sometimes the atrophy progresses so severely as to seriously affect the fitness of the denture, especially the full denture. If the alveolar ridge is markedly resorbed, patients are not satisfied, unless the alveolar process is surgically heightened and the fitness of the denture is regained. Plastic operation of the alveolar process by visor osteotomy and grafting of the iliac bone was performed on a 54-year-old woman who presented at our Department with a complaint of unfitness of the full denture because of marked atrophy of the mandibular alveolar process. As a result of this operation, a functionally well-fitting denture could be fitted to the satisfaction of this patient. This paper describes the outline of the surgical procedure.

Alveolar Ridge Augmentation↗
PubMed1988

Prevention of horizontal transmission of hepatitis B: efficacy of hepatitis B immunoglobulin and vaccine in an institution for the handicapped.

In a Japanese institution for the handicapped with confirmed continuous outbreaks of hepatitis B virus (HBV) infection by horizontal nosocomial transmission, 29 susceptible subjects (8 institutionalized children and 21 medical staff) were injected intramuscularly with anti-human HBs immunoglobulin (HB Ig) and subcutaneously with HB vaccine. All cases acquired HBs antibody after injection of HB Ig and seropositivity for HB after the third inoculation of HB vaccine was 78.6%. No new case of HB occurred among the study population throughout the period investigated. This suggested the effectiveness of HB Ig and HB vaccine in the prevention of horizontal nosocomial transmission of HBV.

Adolescent↗