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Biomedical subjects

K Iga

Publications and source records attributed to K Iga.

At least 73 records · Page 4Linked to original sources
PubMed1992

Deep negative T waves associated with reversible left ventricular dysfunction in acute adrenal crisis.

We report two cases of reversible left ventricular dysfunction associated with deep negative T waves during acute adrenal crisis due to isolated deficiency of adrenocorticotrophic hormone. There were no symptoms suggestive of heart disease in either case and left ventricular wall motion abnormalities, present mainly around the left ventricular apex, returned to normal in 1-2 weeks. Deep negative T waves normalized 4 weeks after corticosteroid administration. Acute adrenal crisis should be considered when deep negative T waves are associated with left ventricular dysfunction without cardiac symptoms.

Adrenal Insufficiency↗
PubMed1992

Heat-induced drug release rate and maximal targeting index of thermosensitive liposome in tumor-bearing mice.

To evaluate the rate of drug release at the tumor and maximal drug targeting after administration of thermosensitive liposomes with hyperthermia, a theoretical and experimental method was derived assessing the fraction of drug released from liposomes in a single pass through the heated tumor, F, and the drug targeting index when drug release occurs completely in response to heat (F = 1), DTImax. The F and DTImax were evaluated for four types of liposomes (LUV-1 and LUV-2, thermosensitive large unilamellar liposomes; LUV-3, a nonthermosensitive large unilamellar liposome; and SUV-1, a thermosensitive small unilamellar liposome) using reported data on blood liposome levels and tumor drug levels after the liposomes were administered to tumor bearing mice. DTImax values for LUV-1 and SUV-1 were approximately 6, while the value for LUV-2 with a relatively large systemic clearance was only 2.3. The F values for LUV-1, LUV-2, and SUV-1 with hyperthermia were 0.71, 1.17, and 0.34, respectively, whereas the values for these liposomes without hyperthermia and for LUV-3 with or without hyperthermia were nearly zero. These results confirm earlier findings that LUV-1 and LUV-2 release CDDP almost completely at the heated tumor and that the large DTI value obtained in LUV-1 (DTI = 4.6) was due to its high heat sensitivity and its small systemic clearance.

Animals↗
PubMed1992

Segmental asynergy of the left ventricle in a case of tight aortic stenosis associated with mild ischemic heart disease.

Emergency aortic valve replacement with double aorto-coronary bypass surgery was performed to treat severe intractable congestive heart failure in an 82-year-old man. Mild circumflex and left anterior descending artery lesions were present and the pressure gradient across the aortic valve was 80 mmHg despite a low cardiac output. The preoperative anteroseptal akinesia seen by two-dimensional echocardiography was normalized after surgery. Thus, even in patients with segmental left ventricular dysfunction, tight aortic stenosis might be present when concomitant mild ischemic heart disease is present.

Aged↗
PubMed1992

Continuous murmur in Lutembacher syndrome analyzed by Doppler echocardiography.

A continuous murmur was heard in a 47-year-old woman with Lutembacher syndrome. Transesophageal and intraoperative Doppler echocardiography revealed the murmur originating from the accelerated blood flow passing through the small atrial septal defect. To our knowledge, this is the first reported case of a continuous murmur in Lutembacher syndrome analyzed by Doppler echocardiography.

Echocardiography, Doppler↗
PubMed1992

Reversible left ventricular dysfunction induced by recurrent ventricular tachycardia.

Two cases of transient LV dysfunction associated with VT are described. Both patients had a history of palpitations of several years' duration without symptoms of congestive heart failure. The reason for presentation was an increase in frequency and duration of palpitation. Decreased LV wall motion, observed by 2DE, normalized shortly after treatment of the VT. Diffusely decreased LV wall motion is associated with frequent episodes of VT and may mimic DCM except that signs and symptoms of heart failure are absent.

Adult↗
PubMed1992

Transient increase in wall thickness of the left ventricular apex after stunned myocardium: a case report.

A case of transiently increased wall thickness in the left ventricular apex after stunned myocardium due to severe attack of vasospastic angina is described. "Ace of spades" configuration, documented by left ventriculogram and increased apical wall thickness of the left ventricle, as revealed by two-dimensional echocardiograms returned to normal in 2 months. This transiently increased left ventricular mass may have been due to myocardial edema, which is occasionally seen in the recovery course of active myocarditis.

Angina Pectoris↗
PubMed1992

[Usefulness of magnetic resonance imaging (MRI) in evaluation of left ventricular apical aneurysm].

Twenty three consecutive cases of left ventricular aneurysm due to antero-septal myocardial infarction in normal sinus rhythm were studied to decide whether or not magnetic resonance imaging (MRI) can evaluate aneurysm of the left ventricular apex. The apex, as well as the base, of the left ventricle was clearly imaged in 21 out of 23 cases. Poor images were obtained in two cases who showed frequent premature ventricular beats during this procedure. Two-dimensional echocardiography has weak points when visualizing left ventricular apex because, for one thing, the sector angle is maximally 90 degrees, and for another, the cardiac apex is too near the probe for observation of the characteristic of the left ventricular apical wall. However, MRI can make up for the above weak points and can provide supportive information by visualizing the entire left ventricular apex.

Adult↗
PubMed1991

Increased tumor cisplatin levels in heated tumors in mice after administration of thermosensitive, large unilamellar vesicles encapsulating cisplatin.

Hyperthermia (HT)-dependent cisplatin (CDDP) release and tumor CDDP level increase after the administration of thermosensitive, large unilamellar vesicles (LUVs: LUV-1 and LUV-2) and a thermosensitive, small unilamellar vesicle (SUV: SUV-1) were examined in comparison with those following administration of a non-thermosensitive LUV (LUV-3) and a CDDP solution (Sol) in tumor bearing mice. The LUV-1 and LUV-2 released CDDP at a faster rate than SUV-1 when incubated in saline at temperatures between 41 and 44 degrees C. The blood CDDP levels after liposome administration were higher than those after Sol administration. The systemic clearance of LUV-2 was slightly larger than those of the other liposomes. The tumor CDDP levels after thermosensitive liposome administration were increased in response to HT in comparison to LUV-3 or Sol. The increased ratio for LUV-1 was the largest. The ratio of the area under the tumor CDDP level versus time curve (AUC) for LUV-1 + HT to the AUC for Sol + HT was approximately 5. The results indicate that (1) the tumor-CDDP level increase after thermosensitive liposome administration is due to CDDP release from the liposome in the blood at or adjacent to the heated tumor, (2) the increase is highly dependent on the heat sensitivity and systemic stability of the liposome, and (3) LUV, such as LUV-1, exhibit higher heat sensitivity and larger, targeted drug delivery efficiency than SUV.

Animals↗
PubMed1991

Transient segmental asynergy of the left ventricle of patients with various clinical manifestations possibly unrelated to the coronary artery disease.

Eight cases of transient reversible segmental asynergy of the left ventricle thought not to be related to coronary artery lesions are reported. Three cases were associated with inflammatory reactions of unknown origin, and one each with lactic acidosis, abdominal surgery, hypoglycemia, tetanus and pneumonia. None of the patients had symptoms suggestive of ischemic heart disease before or after these episodes. Electrocardiograms before these episodes were all normal. Two-dimensional echocardiography was performed to evaluate abnormal electrocardiograms. Coronary angiography was performed in 4 of 8 cases and was normal in all 4 cases; 2 done as emergencies and 2 non-emergencies. Two ergonovine tests were negative. Left ventricular wall motion abnormalities, present mainly at the apex of the left ventricle, returned to normal in 1 to 4 weeks. Giant negative T waves in the chest leads during this recovery period were characteristic electrocardiographic features and normalized in 6 weeks on average. We believe that these episodes were not related to ischemia due to coronary artery disease, but to some metabolic humoral factors. An excellent prognosis can be expected if these abnormal metabolic circumstances can be resolved.

Aged↗
PubMed1991

Native valve infective endocarditis in adults--analysis of 32 consecutive cases over a ten-year period from 1980 to 1989.

Thirty-two patients with native valve infective endocarditis who presented over a 10-year period at our hospital were analyzed retrospectively. The presenting symptom was a persistent fever in 22 patients. In 30 patients, the New York Heart Association functional class was less than II before the development of endocarditis. Blood cultures were positive on all occasions in 24 out of 29 culture-positive patients. All of the viridans streptococci, accounting for 79% of the isolated pathogens, were highly susceptible to ampicillin. Treatment consisted of a 6 week course of antibiotics, usually ampicillin, at a dose of 12 grams/day. In 9 cases, we had to change or stop the antibiotics because of severe side effects. The longer the period before making a diagnosis, the more severe were the symptoms of congestive heart failure and the more frequent was the incidence of cerebral hemorrhage. To initiate treatment as early as possible, in order to minimize valve destruction and to reduce the risk of cerebral hemorrhage, serial blood cultures are recommended in patients with valvular heart disease or congenital heart disease and a persistent fever, with minimal cardiac symptoms.

Adult↗
PubMed1991

Progressive restrictive cardiomyopathy--a case report.

We present a case of restrictive cardiomyopathy which progressed over a 10 month period. A 69-year-old female was admitted because of acute inferior myocardial infarction; hemodynamically, she was in Forrester subset I. Cardiac catheterization performed 4 weeks post-infarction showed markedly increased left ventricular end-diastolic and pulmonary wedge pressures. Left ventricular ejection fraction was 66% with postero-basal akinesis and minimal mitral regurgitation. The right coronary artery was completely occluded with good collateral circulation from the intact left coronary artery. Doppler echocardiography 4 weeks post-infarction showed pseudo-normalization of the A/E ratio of peak mitral flow velocity in atrial systole (A) to peak mitral flow velocity in early diastole (E). Preload reduction by nitroglycerin increased the A wave. Ten months post-infarction, the patient was re-admitted due to congestive heart failure. The A/E ratio was unchanged, however the A wave no longer increased after the same dose of nitroglycerin. We have hypothesized that dehydration and/or the vigorous use of a nitrate, in the acute phase of myocardial infarction, masked an underlying restrictive cardiomyopathy which progressed in the 10 months post-infarction.

Blood Flow Velocity↗
PubMed1991

A case of unusual longevity of tetralogy of Fallot confirmed by cardiac catheterization.

We describe a 61-year-old woman with tetralogy of Fallot and dextrocardia with complete situs inversus. The functional status of this patient was New York Heart Association (NYHA) class II and the systemic blood pressure was 100/54 mmHg. The hematocrit was 54.4% and the arterial partial pressure of oxygen was 53 mmHg. On cardiac catheterization, both pulmonary valvular and infundibular stenoses were of equal severity and the aorta and main pulmonary artery were of equal size. We think that this patient has survived to this unusual age for tetralogy of Fallot because of unusually low systemic pressure and a proper balance between the ventricular septal defect and the pulmonary stenosis.

Cardiac Catheterization↗
PubMed1991

Regression of the left main trunk lesion by steroid administration in Takayasu's aortitis.

A 62-year-old man with unstable angina due to severe narrowing of the left main trunk (LMT) was examined. Emergency bypass surgery was performed with an internal mammary artery graft, instead of a saphenous vein graft, because of the thickened, edematous ascending aorta. Postoperative coronary angiography showed the lesion of the LMT markedly regressing. Presumably, this stenotic lesion of the LMT was caused by active aortitis and was partially reversible by steroid administration both during and after surgery. Steroid therapy can be added to the list of treatments for cases of LMT disease associated with Takayasu's aortitis, if signs of active inflammation are present.

Angina, Unstable↗
PubMed1991

[Two cases of atrial septal defect diagnosed by two-dimensional Doppler echocardiography: comparison with other methods for detecting atrial septal defect].

We describe two cases of atrial septal defect(ASD) diagnosed by chance with two-dimensional Doppler echocardiography(2DD) which was carried out for another purpose. There were no findings characteristic of ASD such as systolic murmurs in the pulmonary area, incomplete right bundle branch block pattern on electrocardiograms, increased hilar shadow on chest films or increased right ventricular chamber diameter in two-dimensional echocardiography. However, the 2DD showed blood flow crossing through the atrial septum. Cardiac catheterization confirmed the presence of a small ASD. ASD diagnosed by 2DD alone without other classical characteristic signs of ASD indicates that the ASD is small and clinically insignificant as it is with Doppler valvular heart disease.

Adult↗
PubMed1991

Enhanced antitumor activity in mice after administration of thermosensitive liposome encapsulating cisplatin with hyperthermia.

The antitumor effect of cisplatin-(CDDP)-encapsulated thermosensitive large unilamellar liposome (ThLip) administration with hyperthermia (HT) was examined in mice bearing Meth A fibrosarcoma. The tumor Pt levels after ThLip administration were increased in response to HT. The targeting index was approximately 3. The antitumor activity of ThLip + HT, as measured by tumor growth delay or tumor weight inhibition, was larger than that of ThLip without HT or a solution with or without HT. The CDDP dose in ThLip + HT to give equivalent tumor growth delay in solution (40 micrograms/mouse) + HT was about 10 micrograms/mouse, and therefore the targeted drug delivery enhancement ratio was about 4. The ratio correlates with the targeting index. The blood urea nitrogen level, as an indicator of CDDP nephrotoxicity, was increased 7 days after the administration of ThLip (40 micrograms CDDP/mouse) with HT. However, this blood urea nitrogen level rise was independent of the activity enhancement by the liposome. These findings suggest that the HT combined CDDP delivery system using ThLip can decrease the effective CDDP dose, thereby increasing its therapeutic index.

Animals↗
PubMed1990

Abnormal venous connection between the left upper pulmonary vein and the left brachiocephalic vein, associated with rheumatic combined valvular heart disease.

A case of partial anomalous pulmonary venous return (PAPVR) associated with mitral stenosis and aortic regurgitation is described. The diagnostic clue was radiocardiography using radioiodide serum albumin (RISA), our routine procedure before cardiac catheterization. The abnormal vessel connected with both the left upper pulmonary vein (PV) and the left brachiocephalic vein, without a stenotic lesion. Aortic valve replacement, open mitral commissurotomy, and simple ligation of the anomalous vein were successfully performed.

Aortic Valve↗
PubMed1990

Gerbil hippocampal extracellular glutamate and neuronal activity after transient ischemia.

In order to elucidate the role of glutamate in the pathogenesis of delayed neuronal death, we analyzed changes in extracellular levels of glutamate induced by transient ischemia in the Mongolian gerbil hippocampus by a new brain microdialysis method combined with an enzymatic cycling technique. We also studied the effect of this change in glutamate on CA1 spontaneous neuronal discharges. The level of glutamate significantly increased during the 5 min of ischemia and during the first 5 min of recirculation. However, neuronal hyperactivity anticipated as a result of the increased extracellular glutamate was not observed. Spike discharges disappeared during and shortly after 5 min of ischemia; CA1 spontaneous spike discharges reappeared about 15 min after the recirculation. The frequency and amplitude of the discharges of CA1 neurons returned to normal by 30 min of the recirculation. However, the pattern of discharges was different from that recorded before the ischemia. CA1 neurons were found dead 4 days after the ischemia. Brief exposure to toxic concentrations of glutamate may cause the delayed neuronal death.

Action Potentials↗