Biomedical subjects

Y Koga

Publications and source records attributed to Y Koga.

At least 379 records · Page 21Linked to original sources

PubMed1990

[A case of complex I deficiency with episodic respiratory distress].

A 7-year-old girl with normal psychomotor development during infancy began to have easy fatigability about 3 years of age. At the age of 5 years, she developed respiratory distress and became unconscious when the serum lactate and pyruvate levels were markedly elevated and a blood gas analysis showed respiratory and metabolic acidosis. Thereafter, she had similar episodic respiratory problems with lactic acidosis. Her muscle biopsy showed a myopathic pattern and numerous ragged-red fibers in an approximately half of muscle fibers. Lipid droplets were slightly to moderately increased in amount mostly in the ragged-red fibers. A biochemical analysis on the isolated mitochondria from the biopsied sample showed markedly decreased NADH cytochrome c reductase activity with no specific but rather uniformly decreased subunits of complex I by the immunoblotting method. She was diagnosed as having the myopathic form of complex I deficiency because she and her relatives with similar muscle symptoms had no central nervous system symptoms such as progressive mental deterioration, convulsions and stroke-like episodes. Diagnosis of complex I deficiency was further confirmed by an oxograph study; the oxygen consumption was not detectable when malate and pyruvate were added as the substrates in the isolated mitochondria. Although stroke-like episodes and convulsions are commonly seen in complex I deficiency, episodic respiratory distress as seen in the present patient has not been described in the literature.

Child↗

PubMed1990

[Postoperative recurrence of the patients with the stage I, II non small cell lung cancer].

The study population consisted of 42 patients with squamous cell carcinoma and 46 patients with adenocarcinoma of stage I, 12 patients with squamous cell carcinoma and 7 patients with adenocarcinoma of stage II lung cancer who underwent curative surgical resection. Local recurrence and metastasis was not significant in both histological types in stage I, II. Lung and bone metastasis was dominant in the both cases of squamous cell carcinoma, adenocarcinoma and brain metastasis in the cases of adenocarcinoma. Concerning the period to first recurrence following the operation, the recurrences of stage I squamous cell carcinoma occurred 28% within 1 year after surgery, 28% during 1-2 years after surgery and those of stage II squamous cell carcinoma occurred 11% within 1 year. On the other hand, the recurrences of stage I adenocarcinoma occurred 25% within 1 year, 31% during 1-2 years, 25% over 2 years after surgery and those of stage II adenocarcinoma occurred 13% within 1 year. In the cases with squamous cell carcinoma, the 5-year survival rate (56%) of stage I was not significant compared with those (59%) of stage II. On the other hand, in the adenocarcinoma, the 5-year survival rate (54%) of stage I was significantly better than those (29%) of stage II (p less than 0.05).

Adenocarcinoma↗

PubMed1990

Prognostic factors in liver metastases after transcatheter arterial embolization or arterial infusion.

From January 1986 to December 1988, 85 patients (55 men and 30 women, mean age 59 years) with metastatic liver tumors were treated with hepatic artery embolization (TAE) or infusion (HAI). Sixty-eight patients with successful catheterization were treated with TAE using iodized oil (Lipiodol) mixed with anticancer agent (ACA). In 12 of 68 patients with hypervascular tumors gelatin sponge was added. Patients with unsuccessful catheterization were treated with hepatic artery infusion of ACA. Forty-three patients received oral chemotherapy following TAE or HAI. Overall, the 6-month, and 1- and 2-year survival rates were 69.5, 31.8 and 4.1 per cent, respectively (mean 233 days). A univariate analysis of prognostic factors showed that number of metastases, stage, treatment times and oral chemotherapy were all significant factors (p less than 0.05). Ascites, jaundice, percentage of hepatic replacement and treatment protocol also had some influence (p less than 0.1). Sex, age, primary site, elevation of tumor markers, other metastatic lesions, portal vein involvement and difference in anticancer agent had no prognostic significance. A multivariate analysis using Cox's proportional hazard model revealed that the number of treatments had the most important prognostic significance, followed by oral chemotherapy, stage and percentage of hepatic replacement.

Antineoplastic Agents↗

PubMed1990

[Surgical treatment of cor triatriatum: report of four cases].

Four cases of cor triatriatum are reported. Cases 1 and 2 had IIA, case 3 had IA, and case 4 had IIIB 1 type of cor triatriatum according to Lucas-Schmidt classification. Cases 1 and 2 were diagnosed by echocardiography preoperatively. They were not performed cineangiocardiography because of pulmonary congestion. Case 3 had type IA so called classical type, which is hemodynamically identical to mitral stenosis and supravalvular stenosing ring. The clinical features are depend on the size of the communication between accessory chamber and true left atrium. As case 4, he had been diagnosed of simple atrial septal defect preoperatively, careful echocardiographic examination was essential for accurate diagnosis. In case 2 with hypoplastic left heart, secondary surgical repair is considered to be desirable followed by balloon dilatation of two atrial septal defects communicated to accessory chamber and to true left atrium. Thus, we expect development of hypoplastic left ventricle.

Adolescent↗

PubMed1990

[Renal function after aortic reconstruction for aortic dissection: special reference to the renal blood flow from false lumen].

Relationships between preoperative renal blood flow and postoperative renal dysfunction after aortic reconstruction for aortic dissection of DeBakey I and IIIb type were discussed. The incidence of renal dysfunction after surgery was not so high and renal failure was transient. Renal dysfunction occurred in the cases with true lumen oppressed by false lumen at chronic stage. Sometimes, abnormal findings were showed in CT scanning and/or renogram even in serum creatinine or BUN value was normal. In conclusion, our data showed justification of anastomosis of distal artificial graft to true lumen in acute stage. But in chronic stage, it is very important in point of selection of operative method to recognize how renal blood flow was preserved and to know the location and size of reentry before surgery.

Adolescent↗

PubMed1990

[Case report of the superior approach for correction of the supracardiac type of total anomalous pulmonary venous drainage (TAPVD) in the neonatal period].

An eleven-day-old newborn with cyanosis and respiratory distress was admitted. Intubation and catecholamine administration had already done. Blood pressure was 80/50 mmHg, heart rate was 160/min. Urine volume was only 7 ml per 4 hours with diuretics. The diagnosis of supracardiac type of TAPVD was done by echo cardiography. Without cardiac catheterization, emergent operation was performed. After median sternotomy, the mobilization of the aorta was done. Under cardiopulmonary bypass the aorta was retracted to the left, the superior vena cava to the right and the common pulmonary venous trunk (CPV) was identified through the transverse sinus. Parallel incision were made in the left atrium and CPV, and extended to the vertical vein. An anastomosis using continuous suture was fashioned. She had a good postoperative course. The superior approach through the transverse sinus affords excellent exposure of the CPV and left atrium in situ in the neonatal period, if the mobilization of the aorta is completed, and the heart is not compressed or displaced. This approach is useful for supracardiac type of TAPVD.

Female↗

PubMed1990

[An experimental study of reconstruction--differences of the healing process by materials].

The healing processes of carinal reconstruction by suture materials; absorbable suture (Vicryl) and nonabsorbable suture (Prolene) were compared. 67 adult mongrel dogs underwent resection of two rings of the trachea and bilateral main bronchi. This was followed by end-to-end anastomosis of the reconstructed carina and the remaining trachea. 3-0 Vicryl or 3-0 Prolene were used respectively. At some intervals, each anastomosis was removed and was analyzed by bronchoscopy, microangiography, scanning electron microscopy (SEM) and light microscopy. Suture insufficiency occurred in two of 32 anastomosis sutured by Vicryl and four of 35 anastomosis sutured by Prolene sutures. Stenosis developed in one of the Vicryl group and two of the Prolene group. Vicryl showed more inflammation than Prolene for 3 weeks after surgery. In four weeks, the inflammation subsided. Anastomoses were of the same degree in both groups. In microangiography, vascular regeneration was abundant by 3 weeks, which normalized in 4 weeks showing a normal network in both groups. Normalization of the vascular network appeared the earliest at the membranous portion. Scanning electron microscopy showed no difference in the reconstruction of the cilia over the anastomosis area in the both groups. This term was 2 months. The order of reconstruction revealed by SEM was the same as observed by microangiography. But in the Prolene group, it took more than 3 months for the suture material to be completely covered with the epithelium. In light microscopy, inflammation was stronger in the group than by in the Prolene groups, and it continued for 4 weeks suture material could not be found in the anastomosis area with bronchoscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

[A case of primary adenosquamous carcinoma of the stomach showing Borrmann 4 type].

Adenosquamous carcinoma is a rare histological type of gastric cancer. We reported a 61-year-old man with primary adenosquamous carcinoma of the stomach showing Borrmann 4 type. Gastrofibroscopic biopsy and lymph node biopsy showed squamous and adenosquamous carcinoma respectively. Operated specimen revealed a adenosquamous carcinoma with diffuse infiltration.

Adenocarcinoma↗

PubMed1989

Absence of transcription of lck (lymphocyte specific protein tyrosine kinase) message in IL-2-independent, HTLV-I-transformed T cell lines.

The expression of lck gene (lymphocyte specific protein tyrosine kinase) in the human system was examined by Northern blot analysis in human T cell leukemia virus type I (HTLV-I)-positive T cell lines, HTLV-I-T cell lines, normal T cell population, and a T cell line infected with human immunodeficiency virus. In the cells of HTLV-I-integrated T cell lines, messages of lck were not detected in IL-2-independent lines, although found profusely in IL-2-dependent ones. The results of nuclear transcription assay indicated that lck expression is shut off at the stage of transcription in those cell lines. RNA products of the viral PX region were not detectable in two out of five HTLV-I+, IL-2-independent lines, suggesting that PX gene products themselves exert no direct effect on the block of lck transcription in the HTLV-I-infected T cells. Other T cell populations and a T cell line infected with human immunodeficiency virus, on the other hand, showed significant levels of lck message. These data presented the possibility that lck gene product may be one of the intervening molecules which transduce the signal from the IL-2R into the cell interior, and play an important role in the pathophysiology of adult T cell leukemia, especially in the transition of these leukemias from the IL-2-dependent stage to IL-2-independent one for their growth.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Persistent hyperkalaemia in vitamin B12 unresponsive methylmalonic acidaemia.

Persistent hyperkalaemia was found in a patient with vitamin B12 unresponsive methylmalonic acidaemia associated with hyperuricaemia. At 3 years and 8 months of age, a serum potassium level of 6.8 mmol L-1 was found when blood gas measurement was normal. One year later azotaemia was noted. At the age of 5 years, renal function studies disclosed hyperaldosteronism, decreased creatinine clearance, reduction of the reabsorption of sodium at distal diluting segments and inadequate concentration of urine at the collecting ducts. The reduction of the reabsorption of sodium, which may have resulted in decreased potassium excretion, and the decrease in glomerular filtration rate, together with the superimposed excess intake of potassium, appeared to be responsible for the hyperkalaemia. Dietary potassium restriction was effective in suppressing the hyperkalaemia.

Child↗

PubMed1989

The effects of pulsatile and non-pulsatile cardiopulmonary bypass on renal blood flow and function.

The physiologic effects of pulsatile and non-pulsatile flow in cardiopulmonary bypass were compared in terms of the relationship between different flow rates and what effects these had on pulsatile and non-pulsatile flow. Forty adult mongrel dogs were used in this study and divided into 5 groups, each comprised of 8 animals, according to the flow rate during cardiopulmonary bypass, namely; 40, 60, 80, 100, or 120 ml/kg/min. The animals were perfused with either pulsatile or non-pulsatile flow for 1 hour, given randomly at the same mean flow rate. At flow rates of 80 and 100 ml/kg/min, the mean arterial blood pressure and total peripheral vascular resistance were significantly lower in pulsatile flow than in non-pulsatile flow, and the renal blood flow was significantly greater in pulsatile flow than in non-pulsatile flow. The renal arterial-venous lactate difference was significantly less in pulsatile flow than in non-pulsatile flow at a flow rate of 80 ml/kg/min, and the renal lactate extraction was significantly higher in pulsatile flow than in non-pulsatile flow at the same flow rate. The renal excess lactate was significantly lower in pulsatile flow than in non-pulsatile flow at a flow rate of 100 ml/kg/min. There were no significant differences in these parameters between the two types of perfusion at flow rates of 40, 60 or 120 ml/kg/min. Pulsatile flow was therefore apparently advantageous, when compared to non-pulsatile flow, in terms of hemodynamics, renal circulation, and metabolism of the kidney at flow rates of 80 and 100 ml/kg/min. However, when the flow rate was 120 ml/kg/min, pulsatile flow and non-pulsatile flow had the same effects.

Animals↗

PubMed1989

Role of adrenergic receptor systems in canine left ventricular hypertrophy.

Although the sympathetic nervous system and catecholamines have been postulated to play an important role in the development of myocardial hypertrophy, the precise mechanism is still ill-defined. We therefore investigated myocardial norepinephrine and the adrenergic receptor systems in two experimental canine models for cardiac hypertrophy; in 12 dogs with surgical cardiac denervation, and in 12 dogs with chronic infusion of a subhypertensive dose of norepinephrine at a rate of 0.04 mg/kg/day. After two months both models induced myocardial hypertrophy, indicated by significant increases in the heart weight, left ventricular wall thickness and cell diameter, as compared with 14 sham-operated control dogs. Cardiac denervation remarkably depleted myocardial norepinephrine while plasma norepinephrine remained unchanged. Both alpha 1- and beta-receptors were up-regulated, with Bmax increasing by 124% and 49%, respectively. The decrease in myocardial cyclic AMP content was relatively small as compared with the marked depletion in myocardial norepinephrine, probably compensated by augmentation of beta-receptor system activity. Chronic norepinephrine infusion also reduced myocardial norepinephrine content possibly due to stimulation of presynaptic alpha 2-receptor inhibiting norepinephrine synthesis and release. The number of alpha 1- and beta-receptors also increased by 97% and 30%, respectively, while myocardial cyclic AMP content remained unchanged. These observations indicate that neither direct stimulation of norepinephrine on the myocardial cell nor increased cyclic AMP is the mechanism for cardiac hypertrophy. A greater increase in the alpha 1-receptor, rather than in the beta-receptors, in both models implies that a disproportional augmentation of the alpha 1-receptor system may play an important role in the development of myocardial hypertrophy.

Animals↗

PubMed1989

Focal cytochrome c oxidase deficiency in various neuromuscular diseases.

To determine whether focal cytochrome c oxidase (CCO) deficiency characterized by scattered fibers with absent CCO activity among normal fibers was a specific finding for mitochondrial myopathies, we studied 389 muscle biopsies from various neuromuscular diseases other than mitochondrial myopathies. Focal CCO deficiency was found in 14 biopsies: 5 of 26 patients with myotonic dystrophy, 3 of 19 with nemaline myopathy, 1 of 7 with distal myopathy with rimmed vacuole formation, 3 of 22 with limb-girdle muscular dystrophy, 1 of 9 with amyotrophic lateral sclerosis, one of 79 with Duchenne muscular dystrophy. Focal CCO deficiency is known to be a crucial finding for chronic progressive external ophthalmoplegia, but it can also be seen in a variety of other neuromuscular disorders, probably as a secondarily induced phenomenon.

Biopsy↗

PubMed1989

Tissue specificity in cytochrome c oxidase deficient myopathy.

Biopsied muscles were treated in 2 ways to demonstrate cytochrome c oxidase (CCO) activity on electron microscopy: (1) one to several muscle fibers were teased off the biopsy in buffer solution after glutaraldehyde fixation, (2) 20-30-microns thick cryostat sections were placed on precooled glass slides and fixed in glutaraldehyde solution at room temperature. After rinsing in buffer, the teased fibers and cryostat sections were stained with cytochrome c oxidase. In both procedures, almost all mitochondria in control muscle fibers stained positively. In CCO deficiency, the enzyme activity differed from tissue to tissue indicating marked tissue specificity. In the fatal infantile form enzyme activity in muscle fibers was absent, but present in fibroblasts, endothelial cells and smooth muscle arterial cells. The enzyme activity in other forms differed from cell to cell, but individual mitochondria in a given cell examined in cross-section showed uniform CCO activity, indicating that there was no intracellular mosaicism of enzyme positive and negative mitochondria.

Adolescent↗

PubMed1989

Depletion of the surface CD4 molecule by the envelope protein of human immunodeficiency virus expressed in a human CD4+ monocytoid cell line.

A CD4+ human monocytoid cell line, U937, was transfected with a constructed plasmid which has the envelope gene of human immunodeficiency virus under the transcriptional control of the human metallothionein IIA promoter and was cloned thereafter. These cloned cell lines (EH and EL cells) expressed the viral gp160 in the cytoplasm. The expression of surface CD4 antigen examined by Leu3a and OKT4 monoclonal antibodies, however, disappeared completely in EH cells, which produce a larger amount of gp160, while diminishing only partly in EL cells, which produce a smaller amount of gp160. These results indicate that the level of expression of surface CD4 antigen correlates inversely with the amount of intracellular gp160. Moreover, immunoprecipitation studies using lysate from EH cells showed that OKT4 monoclonal antibody precipitated a significant number of CD4 molecules even after surface CD4 disappeared. However, Leu3a monoclonal antibody, which recognizes the binding site for envelope protein, could not precipitate any CD4 molecules in the same cell lysate. Taken together, these results suggested that CD4 molecules are still synthesized normally after the augmented production of gp160 in the cells but form a complex with the envelope protein in the cytoplasm and become unable to be transported to the cell surface, resulting in the observed depletion of surface CD4 antigen. This mechanism may explain the decrease or absence of surface CD4 antigens in human lymphocytes infected with human immunodeficiency virus.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1989

Structure of the two promoters of the human lck gene: differential accumulation of two classes of lck transcripts in T cells.

The human T-cell- or lymphocyte-specific gene, lck, encodes a tyrosine kinase and is a member of the src family. In this report we demonstrate that there are two classes of human lck transcripts (types I and II), containing different 5'-untranslated regions, which are expressed from two distinct promoters. No apparent sequence similarity was observed between the 5'-flanking regions of the two promoters. The expression of lck in human T-cell leukemia and carcinoma cell lines and in human peripheral blood T lymphocytes was examined by S1 nuclease and primer extension mapping and by Northern (RNA) blot analysis of total cellular RNA. The following results were obtained. (i) Two RNA start sites in the downstream promoter were used to generate type I transcripts. (ii) The major human type I start site has not been described for the mouse. (iii) At least five RNA start sites in the upstream promoter were used to generate type II transcripts. (iv) In T cells and in two colon carcinoma cell lines, type II transcripts were present in higher amounts than type I transcripts. (v) In T cells treated with phytohemagglutinin, tetradecanoylphorbol acetate, and cyclosporin A, the modulation of lck expression was associated primarily with changes in levels of type II transcripts. The above results suggest that the two human lck promoters are utilized differentially and may be regulated independently during certain physiological states.

Base Sequence↗

PubMed1989

Electrophysiological properties of cultured dog myocytes obtained by endomyocardial biopsy.

Right ventricular cardiac tissue (10-20 mg wet weight) was obtained from anesthetized adult dogs by endomyocardial biopsy. The biopsy could be repeated in one dog every 2 weeks for up to 3 months. Fifty to 200 cardiomyocytes, dispersed with collagenase and trypsin, were collected by centrifugation of the cells with 50% polysucrose-sodium diatrizoate solution (Ficoll-Paque). Single cardiomyocytes were suspended in a minimum essential medium containing 20% fetal bovine serum and 8-bromoadenosine 3': 5'-cyclic monophosphate (0.1 mM) for up to 3 weeks. Approximately 70-80% of the cultured cardiomyocytes were rod shaped after 24 hours (10-20% after 7 days). Cytoplasmic organelles of the cultured cells, examined with a transmission electron microscope, were within the normal range of canine heart morphology in vivo. Resting membrane potential of the cells was about -80 mV when superfused with a Krebs' solution containing 4.7 mM potassium ions. The action potential lasted for 300 msec and had a peak amplitude of about 120 mV. Voltage-clamp experiments demonstrated the presence of an inward calcium current (congruent to 0.9 nA at +9 mV), which was facilitated by isoproterenol (0.1-1 microMs). The background potassium current showed typical inward rectification at potentials more negative than -80 mV. The results indicate that morphological, electrophysiological, and pharmacological properties of the cultured cardiomyocytes were intact. We propose that the culture techniques we have developed can be useful for repeated investigation on functional aspects of cardiac muscles in myocardial disease.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1989

Sudden death in hypertrophic and dilated cardiomyopathy.

The long-term prognosis for 314 patients with hypertrophic cardiomyopathy (HCM) and 82 with dilated cardiomyopathy (DCM) was investigated in an attempt to elucidate clinical variables predicting sudden death (SD). In the patients with HCM, 68% of cardiac deaths occurred suddenly and unexpectedly. Variables associated with an increased risk to SD were young age (less than 30 years), reduced fractional shortening (less than 35%) and elevated left ventricular end-diastolic pressure (greater than or equal to 20 mmHg). Eight of the 10 patients who died suddenly during or immediately after strenuous exercise were less than 30 years old, and the collapse tended to be associated with exercise-induced ST-depression. In contrast, SD occurring during mild activities, resting or sleep was mainly observed in those aged 30 years or more. Ventricular tachycardia was observed on electrocardiographic monitoring in 24% of those 30 years or more, while it was rare in those under 30 years (5%). On the other hand, no SD was found in patients with apical hypertrophy nor in those 50 years or more. These observations suggest that HCM patients at a young age, with impaired left ventricular systolic and diastolic function, have an increased risk to SD. Since exercise-induced myocardial ischemia rather than ventricular arrhythmias appears to be the more likely mechanism for SD for those under 30 years old, restriction of strenuous exercise should be strongly advised for these patients. For those aged from 30 to 50 years, ventricular tachycardia should be controlled by antiarrhythmic agents for the prevention of SD. In patients with DCM, 24% of all cardiac deaths were attributed to SD. Although no variables reliably predicted SD, it was of note that only one patient out of 26 with SV1 + RV5 greater than or equal to 35 mm died suddenly. Whereas ventricular arrhythmias are known to be a contributing cause for SD, the prognostic significance of ventricular tachycardia on electrocardiographic monitoring in predicting SD has not yet been established. In addition, antiarrhythmic agents often precipitate hemodynamic deterioration. It therefore appears that use of antiarrhythmic agents is not a therapy of first choice and that primary treatment should be focused upon improvement in ventricular function in order to prevent SD in patients with DCM.

Adult↗