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Biomedical subjects

J Fukuda

Publications and source records attributed to J Fukuda.

At least 145 records · Page 8Linked to original sources
PubMed1987

Immunohistochemical study of pancreatoblastoma.

Three cases of pancreatoblastoma in children were examined immunohistochemically and the results were compared with those of pancreatic duct carcinoma in adults. The pancreatoblastoma demonstrated positive reactions to alpha-fetoprotein (AFP) (67%: 2/3), alpha-1-antitrypsin (AAT) (100%: 3/3), carcinoembryonic antigen (CEA) (67%: 2/3) and keratin (33%: 1/3), although CEA was only weakly positive in both cases. On the other hand, adult pancreatic duct carcinoma showed positive reactions as follows; AFP: 3% (1/29), AAT: 21% (6/29), CEA: 97% (28/29) and keratin: 93% (27/29). Also, endocrine substances including insulin, glucagon and somatostatin were all negative in the pancreatoblastomas. Two cases of pancreatoblastoma which were immunohistochemically positive for AFP also showed elevation of the serum AFP level clinically. The different expressive pattern of oncofetal antigens in pancreatoblastoma as compared with pancreatic duct carcinoma in adults may provide further supporting evidence for the embryonic nature of pancreatoblastoma, and suggests that such a pattern might be used as a tumor marker for pancreatoblastoma.

Adult↗
PubMed1987

Hemodynamic characteristics of echocardiographic findings in hypertensive patients with negative U waves and effect of an antihypertensive drug, tripamide.

Twenty-four hypertensive patients were divided into a group A with negative U waves (n = 8, mean age, 50 +/- 11 years) and a group B without negative U waves (n = 16, mean age, 49 +/- 11 years). Echocardiographic findings were compared with a group of 20 age-matched normotensive subjects without cardiovascular disease (mean age, 49 +/- 11 years). In addition, the effects of the antihypertensive agent tripamide were assessed in groups A and B. Although hemodynamic parameters such as left ventricular end-systolic and diastolic dimensions, stroke volume and cardiac output were elevated in group A, group B showed an increase in total peripheral resistance. Thus, group A was characterized by high cardiac output, while group B displayed increased peripheral resistance. Tripamide was administered to 14 patients. In group A (6 patients receiving tripamide), left ventricular end-systolic and end-diastolic dimensions were significantly reduced by tripamide along with stroke volume and cardiac output. However, in group B the only significant change in hemodynamic parameters after tripamide administration was a drop in total peripheral resistance. These findings suggest that both the hemodynamics of hypertensive patients and responses to tripamide vary with the presence of negative U waves.

Adult↗
PubMed1986

Single transient K channels in mammalian sensory neurons.

A single-channel recording of the transient outward current (A-current) was obtained from dorsal root ganglion cells in culture using patch-clamp techniques. Depolarization of the membrane patch elicited pulse like current of a uniform amplitude in an outward direction, of which the unitary conductance was 20 pS. Alteration of extracellular ionic compositions indicated that the charge carriers were K ions. A systematic study was made on the voltage-dependence of the ensemble average current; (a) the activation started at a potential around -60 mV; (b) the time course of the activation was relatively rapid; (c) the channel was completely inactivated at a potential positive to -40 mV. Two time constants (tau f = 100 ms and tau s = 4,000 ms) were detected in the decay of the current indicating that the channels had two different states of inactivation. A convulsant, 4-aminopyridine (4-AP), acted on the channel only from the intracellular side of the membrane. 4-AP (5 mM) reduced not only mean open time (by 50%) but also the single-channel conductance (by 20%). The properties of the channel were independent of Ca ions in the intracellular space.

4-Aminopyridine↗
PubMed1986

Myocardial structure in volume-overloaded hearts before and after valve replacement.

The purpose of this study was to evaluate the histological characteristics of left ventricular muscle in volume-overloaded hearts. A preoperative biopsy was obtained in 31 patients: 14 with mitral regurgitation, 14 with aortic regurgitation and 3 with mitral regurgitation and aortic regurgitation. Postoperative tissue samples were available in 15 patients. Histological findings were correlated with echocardiographic and angiographic data before (preop) and one year after (postop) operation. Myocardial cell diameter was correlated with both the end-diastolic (r = 0.77, p less than 0.01) and end-systolic (r = 0.78, p less than 0.01) dimensions of the left ventricle, but was inversely correlated with the end-diastolic wall thickness-to-radius (h/R) ratio (r = -0.71, p less than 0.01). Percent fibrosis increased proportionally to the diameter (r = 0.42, p less than 0.05). For one year after operation, echocardiographic left ventricular dimensions and angiographic left ventricular volumes were significantly reduced (p less than 0.05), but in some patients postoperative values remained greater than normal. With regard to left ventricular morphology, myocardial cell diameter and interstitial fibrosis decreased significantly after valve replacement (p less than 0.05). However, the myocardial fiber remained hypertrophied and interstitial fibrosis remained above normal after surgery. Thus, postoperative ventricular dilatation was dependent upon the degree of myocardial fiber hypertrophy and interstitial fibrosis.

Cardiomegaly↗
PubMed1986

Long-term postoperative status of tetralogy of Fallot.

From 1965 to 1984, 279 patients with tetralogy of Fallot underwent corrective surgery at Niigata University Hospital, and 228 patients were closely followed postoperatively. Late deaths occurred in 12 cases (5.3%), and overall event-free rate at 20 years postoperatively was 76.9%. The most common events were heart failure due to residual cardiac anomaly and symptomatic ventricular arrhythmias. Treadmill test by Ellestad protocol was performed on 74 postoperative patients, 49% of whom could not complete the protocol. These patients had higher RVEDP and lower RVEF than completing patients. Holter ECG was done on 48 long-term postoperative patients, 48% of whom showed complex ventricular arrhythmias. The age at operation was older and postoperative elapsed time was longer in patients with complex ventricular arrhythmias. Although most postoperative TF patients are able to enjoy a normal social life, the treadmill test and Holter ECG revealed that many patients had latent RV dysfunction and complex ventricular arrhythmias with or without significant symptoms. Since the number of symptomatic patients increases after 15 years postoperatively, a regular check-up with cautious observation is important for the patients' care.

Arrhythmias, Cardiac↗
PubMed1985

NGF-dependent and -independent growth of neurites from sympathetic ganglion cells of the aged human in a serum-free culture.

Small pieces of tissue isolated from abdominal sympathetic ganglia in aged male patients were cultured in a chemically defined, serum-free medium. The growth of neurites from pieces of ganglia in cultures with and without 50 ng/ml mouse 2.5S nerve growth factor (NGF) was compared. The NGF stimulated significantly greater regeneration of neurites, causing the growth of long fibers from the ganglion pieces. Many short neurites grew, even in the absence of the NGF, but these were generally short, except for long neurites generated in several nerve cells. A method was devised for the evaluation of NGF-dependent growth of neurites in the culture. The rate of the NGF-dependent growth of neurites, which was calculated by the difference in the total lengths of the NGF-dependent neurites between 2- and 4-day-old cultures, was approximately 160 micron/day. The results indicate that although the growth of neurites from some sympathetic nerve cells of the aged human become independent of the NGF, most of the nerve cells remain dependent on the NGF, even in the stage of senescence.

Culture Techniques↗
PubMed1985

Nerve cells of adult and aged mice grown in a monolayer culture: age-associated changes in morphological and physiological properties of dorsal root ganglion cells in vitro.

In order to differentiate age-associated changes in morphological and physiological properties of mammalian nerve cells, dorsal root ganglion (DRG) cells of aged mice (C57BL/6; 98-99 weeks old) were grown in a monolayer culture. Neurite outgrowth, changes in shape and size of their soma and functional properties of their plasma membranes were compared to those of tissue-cultured DRG cells from young adult mice (4-8 weeks old). Trigeminal root ganglion (TRG) cells of aged mice were also grown in a monolayer culture, and their in vitro growth was compared to that of the aged DRG cells. Nerve cells were dissociated from DRG (or TRG) by digestion with collagenase and by trituration and were grown on collagen-coated plastic dishes for more than 14 days. Growth of neurites and changes in the size and shape of the nerve cell soma were viewed under a phase-contrast microscope, and physiological properties of the plasma membrane were studied by conventional intracellular recordings with a glass microelectrode. Both adult and aged DRG cells grew neurites of various length and underwent changes in shape and size of their soma, which could be divided into 2 stages; early and late. In the early stage of tissue culture (0-60 h in vitro), nerve cells altered their shape from a spherical to a spindle-like form. This change was not associated with the reduction in cell size. In the late stage of the tissue culture (3-14 days and thereafter), the DRG reduced their cell size, while changes in shape remained small. Quantitative comparison of the adult and aged DRG nerve cells revealed the following 3 major differences between 2 cultures: the survival fraction of the aged DRG cells counted at 36-48 h in vitro was 1/4 to 1/10 of that of the adult DRG cells in 3 different tissue culture trials; reduction in the cell size occurred much earlier in the aged than in the adult nerve cells; the rate of reduction in size of the aged DRG cells was large in comparison with that of the adult DRG cells. No difference in neurite growth or in physiological properties (resting membrane potential, input resistance, input capacitance or capability of generating both Na and Ca spikes) was detected between the aged and adult nerve cells in tissue culture.

Aging↗
PubMed1984

Surgical implications of the pathophysiology of advanced valvular heart disease.

The pathophysiology of advanced valvular heart disease and its clinical implications were analyzed. The study was undertaken primarily on 153 recent patients with implantation of central flow valves. The operative mortality rate was 3.9%, with deaths except one related to LOS. There was a higher incidence of LOS in left ventricular volume-overloaded hearts, and a much higher incidence in patients associated with TR: 70% of TR cases with RVEDP higher than 15 mmHg developed LOS. Cardiac contractile reserve proved to be useful index for predicting immediate postoperative and long-term results; less favorable results were indicated in patients with PWE below 10 mm even after epinephrine infusion. In volume-overloaded hearts, the muscle cell diameter of the left ventricle increased proportionally to the dimension of the left ventricle, with interstitial fibrosis representing irreversible morphological change. Patients with a prolonged indocyanine green disappearance rate showed fibrosis of the liver and were complicated more frequently by LOS, hepatic and renal disturbance and increased mortality. Patients with cardiac cachexia were liable to develop LOS postoperatively, and preoperative GIK therapy appeared to be effective in improving depressed metabolism and hemodynamics, except in patients with severe TR.

Adult↗
PubMed1984

Development of left ventricular muscle in tetralogy of Fallot.

Age-related changes of the muscle fiber diameter of the left ventricle were studied in 20 autopsied specimens of tetralogy of Fallot (TOF) and in 34 normal autopsied hearts. According to the amount of pulmonary blood flow, two groups were defined: In Group 1, TOF with a markedly decreased pulmonary blood flow. In Group 2, TOF with a moderately decreased pulmonary blood flow. In Group 1, the muscle fiber diameter was nearly normal at birth, but increased slightly and remained constant after one year, so that it was significantly less than normal. Moreover, histological observation revealed underdevelopment of the left ventricular muscle fibers in this group. In Group 2, the diameter increased with age in a manner similar to normal and, histologically, the muscle fibers were not different from normal ones except for those in one heart with left ventricular hypertrophy. The growth of muscle fibers in the left ventricle seems to depend on the volume of pulmonary blood flow, or the left ventricular inflow volume. If the left ventricular functional capacity correlates with the growth of muscle fibers, left ventricular dysfunction after the corrective operation may originate in the underdevelopment of muscle fibers. Surgical intervention is advisable before the retardation of muscle fiber growth has become apparent.

Age Factors↗
PubMed1983

Sympathetic ganglion neurons from aged humans grown in monolayer culture.

Sympathetic ganglia were dissected from aged patients during surgical operation done for a therapeutic purpose in the University Hospital. Nerve cells were isolated from the ganglia by trituration after incubation with collagenase, and were grown on collagen-coated plastic dishes with a growth medium. These nerve cells regenerated their axons and survived in the tissue culture for more than 3 weeks. The nerve cells tended to reduce the size in an early stage of the in vitro growth.

Aging↗