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Biomedical subjects

S Doi

Publications and source records attributed to S Doi.

At least 91 records · Page 5Linked to original sources
PubMed1995

Does hypoplasia of one pulmonary artery preclude a definitive repair in pulmonary atresia, intact ventricular septum, and hypoplastic right ventricle?

Twins with pulmonary atresia, intact ventricular septum, and hypoplastic right ventricle associated with underdeveloped and discontinuous left pulmonary artery are described. Operations to connect the left pulmonary artery to the main pulmonary trunk, with subsequent biventricular repair assisted by bidirectional cavopulmonary anastomosis and atrial fenestration were performed. Follow-up catheterization proved spontaneous closure of the fenestration in one patient. Both patients have been in a satisfactory condition for 3 years since operation.

Anastomosis, Surgical↗
PubMed1995

The global bifurcation structure of the BVP neuronal model driven by periodic pulse trains.

The response characteristics of the BVP (Bonhoeffer-van der Pol or FitzHugh-Nagumo) neuronal model to periodic pulse trains were investigated. The global bifurcation structure of model relative to stimulus intensity and period were analyzed using a one-dimensional mapping called the phase transition curve (PTC) extended by Maginu. The PTC clarified how periodic and chaotic responses bifurcate and revealed in particular several examples of chaotic responses bifurcating through period-doubling bifurcations, as well as the coexistences at the same parameter values, of two different periodic orbits, or of a chaotic and a periodic responses.

Animals↗
PubMed1995

QRST isointegral map reflects the sudden reduction of right ventricular pressure after balloon pulmonary valvuloplasty.

To elucidate the mechanism of electrocardiographic changes due to right ventricular pressure overload, serial changes on body surface maps recorded in two children with valvular pulmonary stenosis before and after successful reduction of right ventricular pressure by balloon valvuloplasty (BVP) were studied. Body surface maps and 12-lead electrocardiograms were simultaneously recorded before and 1-1.5 hours, 8 hours, and 5 days after BVP. Before BVP, QRST isointegral maps showed either two maxima or an expanded single maximum on the right anterior chest. These abnormal characteristics become normal or near normal 1-1.5 hours after BVP. Electrocardiographic waveforms and QRS and ST-T isointegral maps showed minimal changes. Changes in QRST isointegral maps were observed near the center of the midanterior chest. These results suggest that increased right ventricular pressure caused a primary repolarization abnormality in the mid-anterior chest that was easily detected by body surface QRST isointegral maps.

Body Surface Potential Mapping↗
PubMed1995

Ga-67 and Tc-99m (V) DMSA imaging in non-Hodgkin's lymphoma with amyloid tumor.

This report describes the localization and categorization of tumors using Ga-67 and Tc-99m (V) DMSA imaging in a rare case of non-Hodgkin's lymphoma associated with an amyloid tumor. Ga-67 uptake was found in both the lymphoma and the amyloid tumor. Significant Tc-99m (V) DMSA uptake was found only in the amyloid tumor. In this case, Ga-67 uptake was nonspecific, but Tc-99m (V) DMSA uptake gave additional information before treatment.

Adult↗
PubMed1995

Clinical and morphologic findings of familial goiter in bongo antelope (Tragelaphus eurycerus).

Inherited defects of thyroglobulin synthesis resulting in congenital goiter are well described in certain breeds of domestic ungulates and in human beings. Goiter associated with synthesis of an abnormal thyroglobulin and the presence of thyroidal albumin was identified in five closely related bongo antelopes (Tragelaphus eurycerus). The goiter had an adult onset, and the affected bongos appeared to remain euthyroid with normal serum T3 and T4 values, normal serum cholesterol concentrations, and nonelevated concentrations of circulating thyroid stimulating hormone (TSH). Goitrous bongos had significant reproductive difficulties, including reduced cyclic activity and prolonged gestations, but were otherwise normal. Over the course of the disease, the thyroid glands greatly enlarged (up to 10 x 20 cm) and became polycystic. Microscopically, there was an admixture of giant colloid-filled follicles and follicles of normal size lined with variable follicular epithelium ranging from squamoid to mildly to moderately hyperplastic. The pathogenesis of goiter in the bongo may reflect a mixture of genetic predisposition coupled with environmental factors, including a period of exposure to a goitrogen.

Animals↗
PubMed1995

[Effects of inhaled beclomethasone on height growth and bone metabolism in children with asthma].

To evaluate the influences of inhaled beclomethasone dipropionate (BDP), 7.3-30.9 (15.5 +/- 6.5) micrograms/kg/day, on bone metabolism and height growth, we performed a longitudinal study for 6 months in 34 children with asthma aged between 3 and 15 years. Bone mineral density estimated by digital image processing method (DIP) and serum level of osteocalcin did not show any significant change, but height growth was slightly suppressed in the patients who inhaled more than 15 micrograms/kg/day of BDP. We concluded that the decision to prescribe inhaled BDP should be made on the balance of the clinical effects and the improvement of quality of life against the possibility of side effects.

Administration, Inhalation↗
PubMed1995

HIV infection in Malaysia: a report of cases seen at the University Hospital, Kuala Lumpur.

The spread of HIV infection into Malaysia is estimated to have occurred in the early 1980's. The first case of AIDS was reported here in 1986. As of March 31, 1994, the numbers have increased to 8049 HIV positive individuals detected in the country. The risk behaviours among those tested positive were intravenous drug use in 77.2%, sexual transmission in 4.5%, while the remainder are still under investigation. Pediatric AIDS constitutes 0.2% of positives. The high prevalence among intravenous drug users (IVDU) is likely to be due to mandatory testing for HIV upon entry to rehabilitation centres. The trend of HIV infection in this country seems to be highest amongst the intravenous drug users. The increasing number of HIV infected prostitutes and heterosexuals in our population is worrying. Since 1986, a total of 104 HIV positive individuals have been treated at the University Hospital, Kuala Lumpur, Malaysia. Of these, 25 have died and of those still alive, 5 have symptomatic disease. The most common AIDS-defining illness is Pneumocystis carinii pneumonia. Education programmes have been developed targeting the various high risk groups and the general population.

Adolescent↗
PubMed1994

Expression of multiple isoforms of protein kinase C in normal human colon mucosa and colon tumors and decreased levels of protein kinase C beta and eta mRNAs in the tumors.

Previous studies have suggested that protein kinase C (PKC) may play an important role in colon carcinogenesis and that human colon tumors have less total PKC enzyme activity than normal tissue. Because PKC is a multigene family that encodes for at least 11 distinct isoforms, in the study reported here we analyzed the expression of six of these isoforms at the mRNA level by northern blot hybridization in 22 pairs of primary colon tumors (of various stages), and adjacent normal mucosa samples. We found that the normal mucosa samples expressed the mRNAs of the following isoforms of PKC, in decreasing order of abundance: PKC delta > PKC eta > PKC alpha > PKC beta > PKC epsilon. There was no consistent difference in the levels of PKC alpha, PKC delta, and PKC epsilon mRNAs between the normal mucosa and the tumor samples. PKC gamma was expressed at a very low level in two of the colon tumors but could not be detected in the remaining tumors or any of the normal mucosa samples. The levels of both PKC beta and PKC eta mRNAs were significantly lower in the tumor samples than in the normal mucosa samples, and this was true of adenomas as well as Dukes' stage A, B, and C adenocarcinomas. Furthermore, the decrease in PKC eta mRNA appeared to be greater in the more poorly differentiated carcinomas. This finding is of interest because PKC eta is normally expressed in the more differentiated cells of epithelial tissues. The decreased levels of both PKC beta and PKC eta mRNAs occurred early in the multistage process of colon carcinogenesis, as it was also seen in adenomas. The functional significance of these changes remains to be determined.

Adenoma↗
PubMed1994

Elevation of circulating monitor peptide/pancreatic secretory trypsin inhibitor-I (PSTI-61) after turpentine-induced inflammation in rats: hepatocytes produce it as an acute phase reactant.

Monitor peptide (MP) is a trypsin-sensitive cholecystokinin (CCK)-releasing peptide purified from rat pancreatic juice on the basis of its stimulatory activity toward pancreatic enzyme secretion and has been reported to exhibit cell growth-stimulating activity. Pancreatic secretory trypsin inhibitor (PSTI) prevents premature activation of trypsinogen in the pancreatic duct. There are two PSTIs (PSTI-61 and -56) purified from rat pancreatic juice on the basis of trypsin inhibitory activity as reported previously. Fushiki et al. (1989, FASEB J. 3, 121) showed that MP is structurally the same peptide as PSTI-61. We measured the serial changes of circulating MP/PSTI-61 in rat and those in the level of PSTI-61 mRNA in the rat liver to investigate another novel role of this peptide in the turpentine-induced acute inflammation model. The elevation of serum MP/PSTI-61 as well as the alpha 2-globulin fraction, which is known to include several acute phase reactants such as alpha 2-macroglobulin and haptoglobin, was observed after induction of the turpentine inflammation. The serum alpha 2-globulin fraction had increased approximately 3-fold over the initial level at 48 hr after the injection. In contrast, serum MP/PSTI-61 had increased approximately 17-fold over the initial level at 48 hr after the injection. The elevation of circulating MP/PSTI-61 was significantly related with that of the alpha 2-globulin fraction (r = 0.91, P < 0.01). Immunoreactive MP/PSTI-61 was detected in the liver after induction of the inflammation (152.5 +/- 16.5 ng/g wet weight), but in the normal rat liver there was no immunoreactive MP/PSTI-61.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Proteins↗
PubMed1994

A modified radial isochron clock with slow and fast dynamics as a model of pacemaker neurons. Global bifurcation structure when driven by periodic pulse trains.

A simple mathematical model of living pacemaker neurons is proposed. The model has a unit circle limit cycle and radial isochrons, and the state point moves slowly in one region and fast in the remaining region; regions can correspond to the subthreshold activity and to the action potentials of pacemaker neurons, respectively. The global bifurcation structure when driven by periodic pulse trains was investigated using one-dimensional maps (PTC), two-dimensional bifurcation diagrams, and skeletons involving stimulus period and intensity. The existence of both the slow and the fast dynamics has a critical influence on the global bifurcation structure of the oscillator when stimulated periodically.

Biological Clocks↗
PubMed1994

Polymerase chain reaction quantification of cytokine messenger RNA expression in peripheral blood mononuclear cells of patients with acute exacerbations of asthma: effect of glucocorticoid therapy.

We have measured the expression of messenger ribonucleic acid (RNA) (mRNA) encoding interleukin-5 (IL-5), IL-4, IL-2 and interferon-gamma (IFN gamma) in peripheral blood mononuclear cells (PBMC) from 10 patients with acute exacerbations of asthma and nine non-asthmatic controls. Measurements were repeated in seven of the asthmatics following 7 days of oral glucocorticoid therapy. Total RNA was extracted from the PBMC, reverse transcribed using oligo-(dT) primers and aliquots of the resulting complementary DNA (cDNA) amplified using the polymerase chain reaction (PCR) in the presence of cytokine-specific primers under non-saturating conditions. PCR products were quantified on a relative basis after Southern blotting and probing with radiolabelled internal oligonucleotide probes by computer assisted densitometry of blot autoradiographs. The relative amounts of IL-5 mRNA in PBMC from the asthmatic patients prior to glucocorticoid therapy were greater (P < 0.01) than those in PBMC from non-asthmatic controls. In contrast, there were no differences in the relative amounts of IL-4, IL-2 and IFN gamma mRNA. In the asthmatics, the relative amounts of IL-5 mRNA correlated with the peripheral blood eosinophil counts (P = 0.02). After oral glucocorticoid therapy of the asthmatics, lung function improved and the relative amounts of PBMC IL-5 mRNA were reduced (P = 0.04) and no longer differed from those in PBMC from non-asthmatic controls. Glucocorticoid therapy was not associated with significant changes in the relative amounts of PBMC IL-4, IL-2 and IFN gamma mRNA. PBMC from atopic subjects contained significantly greater quantities of IL-4 mRNA (P = 0.04) but not IL-5, IL-2 and IFN gamma mRNA compared with non-atopic subjects regardless of their asthmatic status. We conclude that PBMC of patients with acute exacerbations of asthma demonstrate elevated expression of mRNA encoding IL-5, but not IL-2, IL-4 and IFN gamma and that the clinical improvement associated with glucocorticoid therapy is associated with a reduction of IL-5 mRNA expression. We further conclude that elevated expression in PBMC of mRNA encoding IL-4 is a feature of atopy but not of asthma. These observations suggest that IL-5 synthesis by activated T-lymphocytes may be relevant to the pathogenesis of asthma, and that inhibition of this release by glucocorticoids may at least partly explain their therapeutic effect in this disease.

Actins↗
PubMed1994

Immunoadsorption therapy for myasthenia gravis.

The results of a multicentre trial were analysed to evaluate the efficacy of immunoadsorption therapy for severe generalised myasthenia gravis. Twenty patients with myasthenia gravis who were concurrently receiving high dose prednisolone and azathioprine therapy were treated with an affinity-type adsorbent, using tryptophan-linked polyvinyl alcohol gel (IM-TR), according to a standardised treatment protocol. The 20 patients received five adsorption treatments within a period of 10 days. In 11, pronounced improvement of myasthenic weakness was seen and long-term remission was maintained. The treatment was especially effective in patients with thymic hyperplasia. Circulating acetylcholine receptor (AChR) antibodies were reduced by about 60% by treating one plasma volume. There was no difference in the rate of removal of the AChR antibodies between patients with thymic hyperplasia and patients with thymoma. No serious complications occurred during 100 procedures. It was concluded that the immunoadsorption therapy with IM-TR is useful in controlling symptoms in patients with severe myasthenia gravis who are otherwise unresponsive.

Adolescent↗
PubMed1994

Sweetness of glycyrrhetic acid 3-O-beta-D-monoglucuronide and the related glycosides.

To improve the taste profile of glycyrrhizin (1, the saponin of licorice root, relative sweetness to sucrose: x170), a variety of 3-O-glycosides of glycyrrhetic acid were prepared and their sweetness evaluated. It was found that a significant enhancement of sweetness was observed for the 3-O-beta-D-xyloside and the 3-O-beta-D-glucuronide (MGGR). Especially, MGGR had a high sweetness relative to sucrose; x941, and would appear to be a new potent sweetener.

Carbohydrate Sequence↗
PubMed1994

Involvement of the BCL3 gene in two patients with chronic lymphocytic leukemia.

The t(14;19)(q32;q13) is a recurring translocation found in some patients with chronic lymphocytic leukemia (CLL), and the t(14;19) juxtaposes the BCL3 gene on chromosome 19 with the immunoglobulin heavy chain gene (IGH) locus on chromosome 14. Genomic DNAs from 49 patients with chronic B-cell leukemia and the related lymphomas were examined by Southern blot hybridization using 2 separate probes, named p alpha 1.4P and p alpha .5B, from the BCL3 gene locus. None of the 18 patients with leukemic manifestations of non-Hodgkin's lymphomas had detectable BCL3 rearrangements. Of 31 patients with CLL, 2 had the BCL3 rearrangements. A comigration study using the C alpha and C epsilon constant gene probe from IGH indicated that the t(14;19) translocation occurred in these 2 patients, and they were diagnosed with CLL/prolymphocytic (PL) according to the French-American-British (FAB) classification. Probes for the IGH locus revealed that leukemia cells of the 2 patients each were clonal, indicating that both small lymphocytes and prolymphocytoid cells found in the peripheral blood of one patient had the t(14;19), as well as a major population of the small lymphocytes in the peripheral blood of a second patient. It thus appears that tumor cells carrying the t(14;19) constitute a distinct disease entity in a group of chronic B-cell leukemia, that has a converting potential to more aggressive forms.

Aged↗
PubMed1993

Loss of poly(ADP-ribose) synthetase activity without change in arginine-specific ADP-ribosyltransferase activity by acid-treatment; application of the treatment to simple assay for transferase in the presence of poly(ADP-ribose) synthetase.

We investigated the effects of acid treatment (pH 3.5) on the activities of arginine-specific ADP-ribosyltransferase (mono(ADP-ribosyl)transferase) (EC 2.4.2.31) and poly(ADP-ribose) synthetase (EC 2.4.2.30) purified from chicken liver, and we observed that the former enzyme retained completely its activity while there was no evidence for activity of the latter enzyme. Kinetic parameters, including Km values for NAD and whole histones in the reaction catalyzed by acid-treated ADP-ribosyltransferase, were the same as those in the reaction catalyzed by non-treated enzyme. The stereospecificities of the reaction forming ADP-ribosylarginine by acid-treated and non-treated ADP-ribosyltransferases were indistinguishable. We made use of this acid treatment to determine ADP-ribosyltransferase activity in chicken and chick-embryo liver extracts, with a filter assay. The enzyme activities (means +/- S.D. for three separate experiments) of 1-year-old chicken and 13-day-old chick embryo livers were 372.7 +/- 80.20 and 110.6 +/- 27.22 nmol ADP-ribose/g wet liver per h, respectively. This acid treatment is useful for filter assay with labelled NAD of arginine-specific ADP-ribosyltransferase in the fraction containing poly(ADP-ribose) synthetase.

ADP Ribose Transferases↗
PubMed1993

CD4 T-lymphocyte activation in asthma is accompanied by increased serum concentrations of interleukin-5. Effect of glucocorticoid therapy.

Peripheral blood mononuclear cells (PBMC) and serum were obtained, on two occasions, from 15 asthmatic patients who required oral glucocorticoid therapy for moderate to severe disease exacerbations. Samples were obtained immediately before commencement of oral glucocorticoids (Day 1) and again after 7 days of treatment (Day 7), when lung function had significantly improved. Samples were also isolated on two occasions 7 days apart from a group of seven untreated volunteers. Expression of CD25, human lymphocyte antigen (HLA-)DR, CD45RA, and CD45RO on CD4 and CD8 T lymphocytes was measured by flow cytometry, and serum concentrations of interleukin-5 (IL-5) were measured using an enzyme-linked immunosorbent assay technique. On Day 1 the asthmatic patients showed significantly higher percentages, as compared with the control subjects of CD4 T lymphocytes expressing the markers CD25, HLA-DR, and CD45RO and significantly lower percentages of CD4 T cells expressing CD45RA. After glucocorticoid therapy, the percentages of CD4 T cells expressing CD25, HLA-DR, and CD45RO were significantly reduced in the asthmatic patients, and the percentages of those expressing CD45RA significantly increased so that by Day 7 expression of all four markers was no longer significantly different from that of the control subjects. By contrast, the percentages of CD8 T cells expressing HLA-DR, CD45RA, and CD45RO in the PBMC of the asthmatic patients on Day 1 were not significantly different from those in control subjects, whereas the percentages of CD25 expressing CD8 T cells were only marginally elevated. Glucocorticoid therapy resulted in no significant change in the expression of all four markers on CD T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Overexpression of cyclin D1 in rat fibroblasts causes abnormalities in growth control, cell cycle progression and gene expression.

Cyclin D1, a putative G1 cyclin, has been implicated in cell cycle control. The human cyclin D1 gene is located on chromosome 11q13 where DNA rearrangement and amplification have been detected in several types of human cancer. Previous studies demonstrated that the cyclin D1 gene is not only rearranged or amplified but also overexpressed in some of these human tumors and tumor-derived cell lines. To further address the roles of cyclin D1 in cell cycle control and tumorigenesis, we have stably overexpressed the human cyclin D1 cDNA in Rat6 embryo fibroblasts by using retrovirus mediated transduction. The cyclin D1 protein was overproduced about 10-fold and was localized predominately in the nucleus. Cyclin D1 overexpressing cells displayed a decrease in the duration of the G1 phase, decreased cell size, and induced tumors when injected into athymic (nude) mice. In addition, overexpression of cyclin D1 in Rat6 cells perturbed the expression of several cellular growth-related genes including c-myc, c-jun, and cyclin A, but not cyclin D3. Taken together, these results indicate that deregulated expression of the cyclin D1 gene can cause disturbances in cell cycle control and gene expression and also enhance tumorigenesis.

Animals↗