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Biomedical subjects

T Harada

Publications and source records attributed to T Harada.

At least 325 records · Page 18Linked to original sources
PubMed1997

Electroconvulsive therapy for a schizophrenic patient with burns in the critical care centre.

Electroconvulsive therapy (ECT) for a schizophrenic patient with burns in the critical care centre is reported. The patient was a 26-year-old male. He had sustained burns over 45 per cent of his body during a suicide attempt. After admission to the critical care centre, he remained restless despite intensive therapy with neuroleptics. Three months after admission, ECT with muscle relaxation was administered in the critical care centre. After ECT, the patient became emotionally stable and cooperated with the subsequent burn treatment. ECT is available for burned patients along with somatic treatment in critical care centres.

Adult↗
PubMed1997

Hypernatremic suppression of neutrophils.

Phagocytic and bactericidal activities are important functions of the human polymorphonuclear leucocytes (PMNL) as the host defence against burn wound infection. The zone of stasis, just below the zone of coagulation, is a site of interaction between invading bacteria and PMNL. For many reasons the osmotic pressure at this site is elevated. In this study we evaluated the in vitro phagocytic and bactericidal activities of PMNL under hypernatremic conditions. At a sodium concentration of 180 mEq/l, phagocytic activity was suppressed. Although on average superoxide production was maintained within the normal range, it was suppressed in three of the ten cases studied. We conclude that the hypernatremic condition may weaken local defence against burn wound infection at the zone of stasis and may be a risk factor for burn wound sepsis.

Burns↗
PubMed1997

Hypernatremia deepens the demarcating borderline of leukocytic infiltration in the burn wound.

The influence of hypernatremia on progressive burn wound necrosis was evaluated in a second-degree burn model. The depth of the burned tissue sloughed off was measured in a comparative study in the rat (contact burn injury with a metal plate, 70 degrees C for 5 s). Rats in the hypernatremic group were treated with an intraperitoneal fluid injection of hypernatremic saline (10 ml, 850 mEq/l). Control rats were injected with hyponatremic saline (10 ml, 100 mEq/l). On the fourth postburn day specimens were harvested and compared. The greatest depth of leukocytic infiltration (percent of total dermal thickness) was measured. The average depths were significantly different. In zone 1 (from the normal skin edge to 5 mm inside the wound) the average depth in the hypernatremic group was 38.0 +/- 9.3 percent of the dermal depth and in the control group 9.5 +/- 1.2 percent. In zone II (from 5 to 10 mm inside the wound) the hypernatremic group sloughed off at 64.0 +/- 11.8 percent and the control group at 12.5 +/- 2.1 percent. The hypernatremic group showed a deeper demarcating borderline of leukocytic infiltration than the control rats. The wound depth progression may be caused by an osmotic injury.

Animals↗
PubMed1997

Exploring postinfarction reentrant ventricular tachycardia with entrainment mapping.

Ventricular tachycardia late after myocardial infarction is usually due to reentry in the infarct region. These reentry circuits can be large, complex and difficult to define, impeding study in the electrophysiology laboratory and making catheter ablation difficult. Pacing through the electrodes of the mapping catheter provides a new approach to mapping. When pacing stimuli capture the effects on the tachycardia depend on the location of the pacing site relative to the reentry circuit. The effects observed allow identification of various portions of the reentry circuit, without the need for locating the entire circuit. Isthmuses where relatively small lesions produced by radiofrequency catheter ablation can interrupt reentry can often be identified. A classification that divides reentry circuits into one or more functional components helps to conceptualize the reentry circuit and predicts the likelihood that heating with radiofrequency current will terminate tachycardia. These methods are helping to define human reentry circuits.

Cardiac Pacing, Artificial↗
PubMed1997

Catheter ablation of ventricular tachycardia after myocardial infarction: relation of endocardial sinus rhythm late potentials to the reentry circuit.

OBJECTIVES: We sought to determine whether endocardial late potentials during sinus rhythm are associated with reentry circuit sites during ventricular tachycardia (VT). BACKGROUND: During sinus rhythm, slow conduction through an old infarct region may depolarize tissue after the end of the QRS complex. Such slow conduction regions can cause reentry. METHODS: Endocardial catheter mapping and radiofrequency ablation were performed in 24 patients with VT late after myocardial infarction. We selected for analysis a total of 103 sites where the electrogram was recorded during sinus rhythm and, without moving the catheter, VT was initiated and radiofrequency current applied in an attempt to terminate VT. RESULTS: Late potentials were present at 34 sites (33%). During pace mapping, the stimulus-QRS complex was longer at late potential sites, consistent with slow conduction, than at sites without late potentials (p < 0.0001). Late potentials were present at 15 (71%) of 21 sites classified as central or proximal in the reentry circuit based on entrainment, but also occurred frequently at bystander sites (13 [33%] of 39) and were often absent at the reentry circuit exit (3 [23%] of 13). Late potentials were present at 20 (54%) of 37 sites where ablation terminated VT, compared with 14 (21%) of 66 sites where ablation did not terminate VT (p = 0.004). Ablation decreased the amplitude of the late potentials present at sites where ablation terminated VT. CONCLUSIONS: Although sites with sinus rhythm late potentials often participate in VT reentry circuits, many reentry circuit sites do not have late potentials. Late potentials can also arise from bystander regions. Late potentials may help identify abnormal regions in sinus rhythm but cannot replace mapping during induced VT to guide ablation.

Action Potentials↗
PubMed1997

QT corrected for heart rate and relation between QT and RR intervals in beagle dogs.

The beagle dog has been widely used in cardiovascular research, but the adequacy of QT prediction formulas in dogs over a wide range of RR intervals has not been evaluated sufficiently. We investigated the QT-RR relation in beagles by analysis of the QT and preceding RR intervals obtained from 24-h ambulatory electrocardiograms. The acceptability of 14 QT prediction formulas was evaluated by use of 100-150 selected pairs of QT-RR points per animal in seven male and seven female beagles. The accuracy of fit with the measured data was assessed according to the minimum Akaike information criterion. The best fit was given by the logarithmic and inverse Kovács' formulas among one- and two-parameter linear regression equations, respectively. Exponential formulas produced a better fit than did the linear regression formulas, but are impractical because of the complicated interpretation of parameters due to the nonlinearity. In addition, the results obtained under physiological conditions were also confirmed by those of the pharmacological intervention study with disopyramide. Consequently, we propose a one-parameter logarithmic formula (QTc= log600 x QT/logRR) for correcting the QT interval for a heart rate of 100 bpm and the inverse Kovács' formula for evaluating a reverse-use-dependency of QT prolongation.

Animals↗
PubMed1997

Presence of ERK2 in rat retinal cells.

PURPOSE: Extracellular signal-regulated kinase 2 (ERK2) participates in the phosphorylation cascade that is activated in the an early intracellular response to various hormones and growth factors. We examined the expression and distribution of the ERK2 protein and mRNA in the rat retina before and after light exposure. METHODS: Rats were held on a 12 hr light/dark cycle and their retinas were removed and examined either just before or 2 or 30 min after light exposure. The tissue was processed for Western blotting to evaluate the presence of the protein for ERK2, and for in situ hybridization to evaluate the mRNA of ERK2. RESULTS: The Western blotting method showed a strong specific staining of a 42 kDa protein band in the retinal samples. This band corresponded to the expected size of p42 MAP kinase (ERK2). In situ hybridization histochemistry showed an intense localization of ERK2 mRNA in the outer nuclear layer (ONL), the inner nuclear layer (INL), and the ganglion cell layer (GCL) of the retina. The intensity and distribution of these signals did not differ among the animals, regardless of exposure to light. CONCLUSIONS: While ERK2 may be involved in the signal transduction system activated in retinal cells by light exposure, its precise role remains to be defined.

Animals↗
PubMed1997

Risk factors and the effect of interferon therapy in the development of hepatocellular carcinoma: a multivariate analysis in 343 patients.

The aims of the present study were to clarify the risk factors for the development of hepatocellular carcinoma (HCC) in chronic hepatitis C virus (HCV) infection and to investigate the effectiveness of interferon (IFN) therapy. We retrospectively studied 343 patients who had been admitted to our hospital; 161 with chronic hepatitis, 49 with liver cirrhosis, 42 with chronic hepatitis bearing HCC and 91 with liver cirrhosis bearing HCC. The mean (+/- SD) observation period was 41.6 +/- 31.1 months. The mean age of HCC and non-HCC patients was 63.5 +/- 7.6 and 56.9 +/- 12.5 years, respectively (P < 0.001). The HCV genotype II (1b) was the most prevalent genotype (92.5%) in HCC patients and the mean age was higher among patients with this genotype (63.6 +/- 7.7 years). Multivariate analysis identified age (P < 0.001), the male gender (P < 0.01), HCV genotype II (1b) (P < 0.05) and excessive alcohol intake (P < 0.05) as independent factors associated with the development of HCC. There was no relationship between the development of HCC and serum HCV levels as quantified by branched DNA assay or competitive reverse transcription polymerase chain reaction. The incidence of HCC in patients who had not received IFN therapy was 10.4/100 person-year, while that of patients who had received IFN therapy was 1.2/100 person-year (P < 0.01) by the person-year method. The low incidence of HCC in patients treated with IFN suggests that IFN may prevent the development of HCC.

Aged↗
PubMed1997

Therapeutic results of endoscopic variceal ligation for acute bleeding of oesophageal and gastric varices.

Endoscopic variceal ligation (EVL) using 'O' rings is widely accepted as a treatment of oesophageal varices that is at least as effective as endoscopic injection sclerotherapy but which produces fewer complications. Endoscopic variceal ligation using detachable snares has attracted attention as a safe and easy method of endoscopic treatment for gastric varices. Nineteen patients with acute bleeding from oesophageal or gastric varices were treated in the present study. Of these, 14 patients were treated with EVL using 'O' rings and five patients were treated with EVL using detachable snares and the treatment results were evaluated. Haemostasis was achieved in all patients. No serious complications of the procedures were observed. However, recurrences and rebleeding were observed in some patients during the maximum follow-up period of 24 months. Endoscopic variceal ligation using 'O' rings and detachable snares is useful for achieving haemostasis in cases of acute bleeding from oesophageal or gastric varices. However, additional endoscopic sclerotherapy may be needed to eliminate the variceal feeding vessels to further improve the long-term prognosis of these patients.

Acute Disease↗
PubMed1997

Preferential locations for critical reentry circuit sites causing ventricular tachycardia after inferior wall myocardial infarction.

INTRODUCTION: For relatively slow monomorphic ventricular tachycardia (VT) after myocardial infarction, entrainment can be used to identify reentry circuit "isthmus sites" (exit sites and sites proximal to the exit) where radiofrequency (RF) catheter ablation has the greatest likelihood of interrupting reentry. Similarities in coronary and ventricular anatomy may cause such sites to form in preferential locations. The objective of this study is to determine if there are preferential locations for reentry circuit isthmus regions in chronic inferior wall infarctions causing VT. METHODS AND RESULTS: Catheter mapping and RF catheter ablation was performed in 21 patients with an old inferior wall myocardial infarction and VT. The inferior wall was divided into 9 anatomic regions: 3 apical, 3 mid, and 3 basal segments. Of 46 different VTs, an endocardial isthmus site was identified in one or more zones in 28 (61%), with 10 VTs having isthmus sites in two or more adjacent regions. Isthmus zones were found in a basal region of the left ventricle in 24 (86%) of 28 VTs, in a mid segment in 9 (32%) VTs, and in an apical segment in 1 (4%) (P = 0.002). Of 30 RF current applications that terminated VT, 21 (70%) were at basal isthmus sites. CONCLUSION: The high prevalence of endocardial isthmus zones near the base of the left ventricle suggests that the mitral annulus often plays a role in defining the margins of reentry circuits that cause relatively slow VTs after inferior wall myocardial infarction.

Aged↗
PubMed1997

Effect of recording site on postpacing interval measurement during catheter mapping and entrainment of postinfarction ventricular tachycardia.

INTRODUCTION: During entrainment of reentrant ventricular tachycardia (VT), the difference between the postpacing interval (PPI) and the VT cycle length (VTCL) measured at the pacing site is an indication of the conduction time from the pacing site to the reentry circuit. The difference is usually < or = 30 msec at successful ablation sites. However, electrical noise during pacing sometimes obscures the electrograms recorded directly from the pacing site. The objective of this study is to determine if the PPI-VTCL difference measured at the mapping catheter electrodes proximal to the stimulating electrode accurately predicts the PPI-VTCL difference at the stimulating electrode. METHODS AND RESULTS: Endocardial catheter mapping was performed in 26 patients with infarct-related VT. At 191 sites during 56 VTs, unipolar pacing from the distal electrode entrained VT and electrograms recorded from the mapping catheter were discernable following pacing in both the bipolar recordings from the distal electrode pair (BI 1-2) and the electrode pair 6 mm proximal to the distal electrode (BI 3-4). The PPI-VTCL difference at BI 1-2 correlated well with that measured at BI 3-4 (r = 0.88, P = 0.001). A PPI-VTCL difference at BI 3-4 < or = 30 msec predicted a PPI-VTCL difference at BI 1-2 < or = 30 msec with a sensitivity of 95%, specificity of 87 %, and predictive accuracy of 91%. CONCLUSIONS: Measurement of the PPI from electrodes proximal to the stimulating electrode is a reasonable alternative when the PPI cannot be assessed from the pacing electrode.

Aged↗
PubMed1997

An abnormal relationship between blood pressure and pulse rate in amyotrophic lateral sclerosis.

OBJECTIVES: To clarify the autonomic dysfunctions in amyotrophic lateral sclerosis (ALS) patients, we investigated the relationship between blood pressure (BP) and pulse rate (PR), QTc interval, and coefficient of variation in the R-R interval (CVR-R) in ALS patients. MATERIALS AND METHODS: BP and PR were determined automatically every 30 min for 24 h in 6 patients with ALS and in 18 healthy age-matched volunteers. The QTc interval and CVR-R were also evaluated using an electrocardiogram. RESULTS: The relationship between BP and PR was lost in the ALS group. There was no significant difference in the QTc interval or CVR-R between the ALS and control groups. CONCLUSION: We speculate that the imbalance between BP and PR observed in the ALS group reflects a disorder in the balance between the sympathetic and parasympathetic nervous systems.

Adult↗
PubMed1997

Autonomic dysfunction in Parkinson's disease and vascular parkinsonism.

OBJECTIVES: To clarify the autonomic dysfunction in idiopathic Parkinson's disease (PD) and vascular parkinsonism (VP), we investigated the relationship between blood pressure (BP) and pulse rate (PR), the standing test, and the coefficient of variation in the R-R interval (CV[R-R]). MATERIALS AND METHODS: BP and PR were determined automatically every 30 min for 24 h in 15 PD patients, 15 VP patients and 15 healthy volunteers. The CV(R-R) values evaluated by an electrocardiogram and the standing test were also performed. RESULTS: The BP-PR relationship was lost in the patient groups. There was no significant difference in the standing test between the control and patient groups. A significantly decreased CV(R-R) was observed in the VP group. CONCLUSION: We speculate that our results may reflect an imbalance between the sympathetic and parasympathetic nervous systems in PD and VP.

Aged↗
PubMed1997

Plasmapheresis in the treatment of rapidly progressive glomerulonephritis.

The present study was carried out to examine the efficacy of plasma exchange in patients with rapidly progressive glomerulonephritis (RPGN). Seventeen patients with RPGN were treated with plasmapheresis as adjunct to immunosuppressive therapy. Of these, 4 had antiglomerular basement membrane (GBM) antibody-mediated glomerulonephritis (GN), 8 had immune-complex GN (5 SLE, 2 HSP, 1 cryoblobulinemia), 5 had pauci-immune GN (3 peripheral antineutrophil cytoplasmic antibody [P-ANCA], 1 cytoplasmic antineutrophil cytoplasmic antibody [C-ANCA], 1 other). Treatment of 10 of these patients with plasmapheresis within the first month of disease onset resulted in a stable renal function for a period extending from 1 to 3 years, except in 2 patients who had high baseline levels of serum creatinine. In the remaining patients, 2 were treated with hemodialysis 6 years later at the end of follow-up. We conclude that plasmapheresis, when used in combination with immunosuppressive drugs, is beneficial, leading to improved renal function.

Basement Membrane↗
PubMed1997

[Cytomegalovirus retinitis in a patient with systemic lupus erythematosus].

We report a rare case of cytomegalovirus (CMV) retinitis in association with systemic lupus erythematosus (SLE). A 36-year-old female was admitted to our hospital because of nephrotic syndrome and renal insufficiency due to lupus nephritis. After steroid and immunosuppressant treatment for lupus nephritis, she began to complain of floaters and visual disturbance. She was diagnosed as having CMV retinitis based upon the depressed immune status and the clinical appearance of fundus. As soon as CMV retinitis was diagnosed, antiviral treatment with intravenous ganciclovir was instituted and maintained for 7 months. She was treated successfully and almost no progression or relapse of CMV retinitis was documented without ganciclovir maintenance treatment during a 2 year follow-up period. It is suggested that CMV retinitis can occur in patients with SLE treated with steroid and immunosuppressant, indicating the importance of early diagnosis and treatment for CMV retinitis.

Adult↗
PubMed1997

[Study of diarrhea-inducing strains of Escherichia coli mainly isolated in Kanto area between June and September 1996].

A total of 21,609 faecal specimens obtained from patients with diarrhea mainly in Kanto area between June and September 1996 were investigated to identify the causative pathogens for diarrhea. One-hundred fifty-seven strains of Escherichia coli of 29 different O-serotypes were isolated as the causative pathogens, which were previously recognized to induce severe abdominal cramps and diarrhea. Of these, 114 strains, in which the possibility of enterohemorrhagic E. coli due to their O-serotypes was predicted, were examined for the producibility of Vero toxins. Twenty-six (76.5%) of the 34 strains of E. coli O157 produced the Vero toxins, and other 8 strains were the non-producers. Twenty of the 26 producers produced both VT1 and VT2, whereas the other 6 strains produced VT2 only. Furthermore, 4 strains of E. coli O26, and 1 strain each of E. coli O125 and O126 produced Vero toxins. Thirty-two of the 114 strains, isolated from the patients with diarrhea and selected as the enterohemorrhagic E. coli according to the specific O-serotypes, were actually confirmed produce Vero toxins. Thirty-four strains of E. coli O157 tested were susceptible to all antibiotics such as ampicillin, doxycylin, levofloxacin, fosfomycin, chloramphenicol and polymyxin B, and no strains resistant to levofloxacin, polymyxin B and fosfomycin were found.

Bacterial Toxins↗