Biomedical subjects

T Baba

Publications and source records attributed to T Baba.

At least 145 records · Page 8Linked to original sources

PubMed1998

Elevation of serum human hepatocyte growth factor (HGF) level in patients with pneumonectomy during a perioperative period.

OBJECTIVE: Proliferation of alveolar type II cells is thought to be critical for the restoration of lung function after diffuse alveolar damage or pneumonectomy. However, the factors that regulate alveolar type II cell proliferation, and the mechanism that brings about compensatory lung growth are not well understood. Hepatocyte growth factor (HGF) has been shown to have hepatotrophic and nephrotrophic functions for regeneration of the liver and kidney. We have attempted to investigate the involvement of HGF in lung regeneration after lung resection. DESIGN: A prospective, controlled study. SETTING: Adult surgical patients in a university hospital. PATIENTS AND MEASUREMENTS: We measured serum HGF levels in eight patients undergoing major lung resection, and in five patients undergoing mastectomy as controls, by using radioimmunoassay and an enzyme-linked immunosorbent assay. RESULTS: In all cases of pneumonectomy, the serum HGF levels increased 3- to 5-fold at 1-3 days (with a peak at 3 days) after operation, and then decreased to nearly basal levels in 2 weeks. However, these levels in patients undergoing mastectomy did not change much over the first 2 weeks, postoperatively. CONCLUSIONS: Serum HGF levels increased in patients after major lung resection, which suggests that HGF might play an important role in lung regeneration or compensatory lung growth in humans.

Analysis of Variance↗

PubMed1998

Immunocytochemical study of lysosomal proteins with a new monoclonal antibody directed against epithelioid macrophages.

A monoclonal antibody, EPI-1, was produced against macrophages in epithelioid granulomas induced in rat foot pads by muramyl dipeptide. This EPI-1 antibody reacted to lysosome-like structures in epithelioid macrophages, peritoneal and pulmonary macrophages, and also in other tissues such as liver, testes, and kidneys. Western blot analysis of epithelioid granulomas, liver, testes, and kidneys revealed the same positive band of 62 kDa. Immunoelectron microscopic study of foot pad granulomas and hepatocytes demonstrated the EPI-1 antigen located in lysosomes and autophagic vesicles, preferentially along their membranes. These findings suggest that the EPI-1 antibody may recognize a novel antigen related to lysosomal membrane proteins in macrophages and other cells, which is useful for identifying lysosomes and their related structures.

Animals↗

PubMed1998

Re-replacement for prosthetic valve dysfunction: analysis of long-term results and risk factors.

BACKGROUND: Prosthetic heart valve re-replacement still remains a challenging situation. Although some studies have examined the early results, the long-term survival has not yet been well analyzed. The aim of this study was to detect the factors that affect the long-term outcome of operation. METHODS: Between April 1964 and September 1996, 231 prosthetic valve re-replacements were performed including 16 cases of third valve replacement. There were 100 men and 131 women with a mean age of 47 +/- 14 years. RESULTS: The actuarial survival rate was 65% +/- 4% at 5 years and 41% +/- 7% at 10 years. Multivariate analysis revealed that New York Heart Association class IV and left ventricular ejection fraction were found to be independent predictors of late death. CONCLUSIONS: Our study showed that advanced New York Heart Association functional class and lower left ventricular ejection fraction were found to be independent predictors of late death. If operation is performed before patients reach such a deteriorated condition, long-term results are excellent.

Aged↗

PubMed1998

Effects of nicorandil, a potassium channel opener, on idiopathic ventricular tachycardia.

OBJECTIVES: We assessed the effects of the adenosine triphosphate (ATP)-sensitive potassium channel opener, nicorandil, on ATP- and verapamil-responsive ventricular tachycardias (VTs). BACKGROUND: Adenosine- or ATP-sensitive VTs are thought to be due to a nonreentrant mechanism, presumably delayed afterdepolarization. We suggest that this potassium channel opener may suppress ATP- and verapamil-sensitive VTs. METHOD: The subjects included 13 patients with idiopathic VTs, 7 of whom had sustained VT and 6 of whom had nonsustained VT. We evaluated the effects of ATP, nicorandil and verapamil on VTs. RESULTS: Sustained VT: Verapamil had preventive effects on seven VTs. Four VTs were terminated by ATP, and of these, nicorandil terminated two and prevented exercise-induced VT in the two others. Three ATP-insensitive VTs, which were determined to be due to a reentry by an electrophysiologic study, were not terminated by nicorandil. Nonsustained VT: All six VTs were inhibited by ATP, and five of these were suppressed by nicorandil. Verapamil inhibited four of the five VTs. QT intervals and the corrected QT intervals were significantly shortened by nicorandil. CONCLUSIONS: Nicorandil suppresses ATP- and verapamil-responsive VTs. One of the mechanisms of suppression by nicorandil might be related to a reduction of calcium in the myocardium, because it reduces the action potential duration.

Adenosine Triphosphate↗

PubMed1998

Instruments of microbial warfare: bacteriocin synthesis, toxicity and immunity.

Bacteria have devised ingenious enzymatic machinery to synthesize antibiotic molecules (bacteriocins) for their continuous warfare with other microorganisms. Synthesis and export of these toxic compounds are coordinated to ensure the proper extracellular activation of bacteriocin toxicity. In designing future antibiotics, some of the tricks used by bacteriocins might be exploited for the synthesis of novel compounds.

Amino Acid Sequence↗

PubMed1998

p-Aminobenzamidine-sensitive acrosomal protease(s) other than acrosin serve the sperm penetration of the egg zona pellucida in mouse.

It has been reported that a significant delay in protein dispersal from the acrosomal matrix is observed in wild-type sperm by adding p-aminobenzamidine, a trypsin/acrosin inhibitor, to the incubation medium. The pattern of this delayed release was similar to that of the acrosin-deficient mutant mouse sperm (Yamagata et al., J. Biol. Chem., 273, 10470-4, 1998). In the present study, no further delay in protein dispersal was found when the acrosin-deficient sperm were treated with p-aminobenzamidine, indicating that among the p-aminobenzamidine-sensitive protease(s) only acrosin may function to accelerate this process. Although the acrosin-deficient sperm penetrated the zona pellucida (Baba et al., J. Biol. Chem., 269, 31845-9, 1994), the addition of p-aminobenzamidine to the fertilisation medium caused a significant inhibition of fertilisation in vitro. This indicates that there is a p-aminobenzamidine-sensitive protease(s) other than acrosin participating in the zona penetration step. Indeed, we demonstrated that a non-acrosin protease with a size of 42 kDa was present in the supernatant of the acrosome-reacted sperm suspension. The enzyme was inhibited by p-aminobenzamidine, diisopropyl fluorophosphate and N alpha-tosyl-L-lysine chloromethyl ketone, and was apparently activated by acrosin.

Acrosin↗

PubMed1998

Immunolocalization of myotonic dystrophy protein kinase in corbular and junctional sarcoplasmic reticulum of human cardiac muscle.

The subcellular localization of myotonic dystrophy protein kinase has been examined in human cardiac muscles with confocal laser-scanning microscopy and electron microscopy. A polyclonal antibody was produced against the synthesized peptide from a human kinase cDNA clone. We checked the antibody specificity for cardiac myotonic dystrophy protein kinase using an immunoblotting technique. Immunoblotting of extract from human cardiac muscles showed mainly 70 kDa and 55 kDa molecular weight bands. Confocal images of the protein kinase immunostaining showed striated banding patterns similar to those of skeletal muscles. In addition, the kinase was strongly detected around the intercalated disc. Immunoelectron microscopy showed that the kinase was mainly expressed in both corbular and junctional sarcoplasmic reticulum, but not in network sarcoplasmic reticulum. These results suggest that myotonic dystrophy protein kinase may be involved in the modulation of Ca2+ homeostasis in cardiac myofibres.

Blotting, Western↗

PubMed1998

Immediate-type heat urticaria: report of a case and study of plasma histamine release.

We report a 68-year-old man who had immediate-type heat urticaria with systemic symptoms. Immersing his hand in water at 42 degrees C (heat challenge test) produced an urticarial response, with an increase in the plasma histamine level from 0.26 to 7.64 ng/mL. Administration of oral antihistamines alone did not suppress either the urticarial response or the increase in plasma histamine. However, a combination of antihistamines and desensitization improved the skin lesions and reduced the plasma histamine level. The heat challenge test subsequently provoked a negative response and there was no increase in plasma histamine level 3 months after starting the combination therapy. These results indicate that the histamine level reflected the result of the heat challenge test and the amelioration of the skin eruption.

Aged↗

PubMed1998

Morphological study by an 'in vivo cryotechnique' of the shape of erythrocytes circulating in large blood vessels.

Changes in the shape of erythrocytes circulating in large blood vessels of mice were examined by our 'in vivo cryotechnique'. The abdominal aorta and inferior vena cava (IVC) were cut vertically with a precooled knife and simultaneously an isopentane-propane mixture (-193 degrees C) was poured over them for freezing. They were freeze-substituted in acetone containing 2% osmium tetroxide. Some specimens were embedded in Quetol-812, and thick or ultrathin sections were examined by light or transmission electron microscopy. Serial ultrathin sections were used to reconstruct 3-dimensional images of native erythrocytes. Others were transferred into t-butyl alcohol and freeze-dried for scanning electron microscopy. The tissue surfaces were sufficiently frozen to prevent large ice crystal formation, and erythrocyte shapes were also preserved. The shapes of circulating erythrocytes appeared to be varied in the abdominal aorta but typical biconcave discoid shapes were rarely observed. Conversely, erythrocytes were approximately biconcave discoid in shape in the IVC. Our in vivo cryotechnique was useful for clarifying the in vivo morphology of erythrocytes circulating in large blood vessels.

Animals↗

PubMed1998

Inhibitory effect of beta-thujaplicin on ultraviolet B-induced apoptosis in mouse keratinocytes.

Sunburn cells are thought to represent ultraviolet B-induced apoptotic keratinocytes. It has been demonstrated that enzymatic and nonenzymatic antioxidants effectively suppress sunburn cell formation, indicating that reactive oxygen species may play a role in the progression of ultraviolet B-induced apoptosis. Metallothionein, a cytosol protein, has antioxidant activity, and overexpression of metallothionein has been reported to reduce the number of sunburn cells in mouse skin. We have also demonstrated that overexpression of metallothionein inhibits ultraviolet B-induced DNA ladder formation in mouse keratinocytes. These findings support the hypothesis that cellular metallothionein may play an important role in the inhibition of ultraviolet B-induced apoptosis in keratinocytes through its antioxidant activity. In the present study, we investigated the effects of beta-thujaplicin, an extract from the woods of Thuja plicata D. Don. and Chamaecyparis obtuse, Sieb. et Zucc., on ultraviolet B-induced apoptosis in keratinocytes and on metallothionein induction. Topical application of beta-thujaplicin decreased the number of ultraviolet B-mediated sunburn cells and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling-positive cells in mouse ear skin. Incubation with beta-thujaplicin suppressed ultraviolet B-induced DNA ladder formation in cultured mouse keratinocytes. Histochemical analysis showed that topical application of beta-thujaplicin induced metallothionein protein in mouse skin. Northern analysis and western blotting revealed significant induction of metallothionein mRNA and metallothionein protein, respectively, in beta-thujaplicin-treated cultured mouse keratinocytes. These findings indicate that beta-thujaplicin inhibits ultraviolet B-induced apoptosis in keratinocytes and strongly suggest that the inhibitory mechanism is due to the antioxidant activity of metallothionein induced by the agent.

Animals↗

PubMed1998

Novel function of metallothionein in photoprotection: metallothionein-null mouse exhibits reduced tolerance against ultraviolet B injury in the skin.

We have shown previously that injection of cadmium chloride (Cd2+) depletes the number of ultraviolet B (UVB)-induced sunburn cells in the mouse skin in vivo, and that Cd2+ treatment enhances UVB resistance in cultured keratinocytes in vitro, indicating the photoprotective role of Cd2+-induced metallothioneins (MT) with antioxidant property against UVB injury; however, there has been no direct evidence for the role of MT in UV protection. To improve our understanding of MT in photoprotection, MT-null mouse deficient in its MT-1 and MT-2 genes was studied. Skin explants were preliminarily exposed to medium alone, Cd2+ and Cd2+ plus buthionine S,R-sulfoximine, an inhibitor of glutathione synthesis. We then compared the number of UVB-induced sunburn cells and apoptotic cells in the epidermis of MT-null mice with that of control mice using organ culture systems. The skin of MT-null mice developed a greater number of sunburn cells and apoptotic cells than did that of normal mice in all experimental conditions. These findings indicate that the skin of MT-null mouse is readily injured by UVB irradiation. MT-null mouse provided direct evidence of the photoprotective effect of cellular MT in the skin.

Animals↗

PubMed1998

Beta3-adrenergic receptor gene polymorphism is not associated with hypertension in NIDDM patients without nephropathy.

OBJECTIVE: We studied the relationship between a Trp64Arg mutation of beta3-adrenergic receptor gene and hypertension in Japanese NIDDM patients without nephropathy. RESEARCH DESIGN AND METHODS: Eighty-three Japanese NIDDM patients (46 men, 37 women, known duration of 12 [5-31], age of 55 [40-69] years, median and [range]) with normoalbuminuria and microalbuminuria were studied. The Trp64Arg mutation in the beta3-adrenergic receptor gene was determined by the PCR-RFLP method. RESULTS: The frequency of the mutated allele was not greater in the hypertensive patients (18.2%, n=37) than in the normotensive (20.2%, n=46) patients. Genotypes with a mutate allele (i.e. Trp64/Arg64 + Arg64/Arg64) were observed in 23.5% in the hypertensive patients and in 35.7% in the normotensive patients, respectively. A similar finding in the allele frequency was observed when the analysis was made separately in the normoalbuminuric and microalbuminuric patients, respectively. CONCLUSION: These results suggest that a Trp64Arg mutation in the beta3-adrenergic receptor gene is not associated with hypertension in Japanese NIDDM patients without nephropathy.

Adult↗

PubMed1998

Scanning electron microscopic study of flowing erythrocytes in hepatic sinusoids as revealed by 'in vivo cryotechnique'.

The purpose of this study is to develop a method for stabilizing erythrocytes under flowing condition in living livers, as revealed by scanning electron microscopy (SEM). After the procedure of the 'in vivo cryotechnique', both freeze-substitution and subsequent t-butyl alcohol freeze-drying methods were used for preparing SEM specimens. By freeze-fracturing with a scalpel in liquid nitrogen before the freeze-substitution, better preserved surface tissues were obtained for examination. Erythrocytes in hepatic sinusoids were clearly detected without plasma components by the freeze-substitution method, and well preserved in parts where they were flowing with their original shapes. Some were accumulated in sinusoids, especially injunctioning areas of sinusoidal networks, as compared with those in narrow lumens between hepatocyte plates. Shapes of such erythrocytes were various, locating along endothelial cells. After stopping the blood supply into livers by artificial cardiac arrest, their shapes were dramatically changed into biconcaves and they became aggregated side by side to be packed in the sinusoids. The three-dimensional shapes of flowing erythrocytes in hepatic sinusoids were demonstrated for the first time by the 'in vivo cryotechnique' combined with SEM.

Animals↗

PubMed1998

Scanning electron microscopic study of erythrocyte shapes artificially jetted through tubes at different pressures by 'in vitro cryotechnique for erythrocytes'.

A new cryotechnique for examining morphological changes of human erythrocytes at different jet pressures was developed in the present study. Human fresh or stored erythrocytes passing through a tube were jetted into precooled isopentane-propane mixture (-193 degrees C), which was named as 'in vitro cryotechnique for erythrocytes'. After the cryotechnique procedure, the routine freeze-substitution method and subsequent t-butyl alcohol freeze-drying method were used for preparing the scanning electron microscopic specimens. At 100 mmHg or higher pressures of jetting, lamellar-arranged erythrocytes were observed to have elongated shapes. The more the jetting pressure increased, the fewer discoid shapes of erythrocytes were observed. This cryofixation technique could preserve the morphology of erythrocytes jetting from tubes, and provide the three-dimensional image of erythrocyte surfaces, as followed by scanning electron microscopy.

Erythrocyte Deformability↗

PubMed1998

Effect of tylosin tartrate (Tylan Soluble) on cellular immune responses in chickens.

Although many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance immune function. Tylosin is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on cellular immune functions in chickens. There was no significant difference in adherent splenocyte chemotaxis between tylosin-treated and untreated (control) chickens. Tylosin increased splenocyte proliferation and splenocyte conditioned medium (CM) proliferative activity above control levels. Removal of adherent splenocytes before preparation of CM caused a reduction in CM proliferative activity. Tylosin also increased antitumor activity of splenocytes. These data are the first to suggest that the macrolide antibiotic, tylosin tartrate, has a modulatory effect in chickens on the immune parameters studied.

Animals↗

PubMed1998

Hemodynamic effect of amrinone depends on pretreatment vascular resistance in patients with evolving congestive heart failure: correlation between vascular resistance and neurohormonal activity.

We investigated the hemodynamic effects of amrinone and assessed its effects on neurohormonal factors in 15 patients with evolving congestive heart failure with various origins. We serially determined the pulmonary and systemic vascular-resistance indices after amrinone infusion and examined the relation between changes in hemodynamic parameters and changes in concentrations of norepinephrine, atrial natriuretic peptide, angiotensin II, and endothelin-1 in the pulmonary capillary wedge region (PCWR) and in the peripheral veins. Amrinone significantly reduced pulmonary vascular-resistance index (PVRI; Wood x m2) in patients with high PVRI (> or =15) before the infusion, significantly reduced systemic vascular-resistance index (SVRI; Wood x m2) in patients with high SVRI (> or =50) before the infusion, and had little effect on vascular resistances in patients with low PVRI (<15) and low SVRI (<50). The reduction in PVRI was correlated with the reduction in the endothelin-1 level (r = 0.75) in the PCWR, and the reduction in SVRI with norepinephrine level (r = 0.70) in the peripheral veins. The angiotensin II level did not change throughout the study. These findings suggest that amrinone had selective hemodynamic effects on pulmonary and systemic circulations with neurohormonal effects, according to PVRI and SVRI before infusion.

Aged↗

PubMed1998

Effect of tylosin tartrate on humoral immune responses in chickens.

While many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance the immune function. Tylosin tartrate is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on the humoral immune functions in chickens. Three days after oral tylosin tartrate administration, 4- or 8-week-old chickens were immunized intravenously with carbolic acid-killed Brucella abortus bacterin or sheep red blood cells. Seven days (plasma antibodies titre) or 4 days (antibody forming cells) post-immunization, there was a significant increase in antibody production as well as in the numbers of antibody-producing cells in tylosin tartrate-administered chickens compared with the untreated controls. However, 3 days after tylosin tartrate administration, there was no difference in the distribution of T-lymphocyte subpopulations (CD4 or CD8 positive cells) or B lymphocytes (surface immunoglobulin positive cells) in either the peripheral blood or spleens or untreated control chickens.

Animals↗

PubMed1998

Right parasternal minithoracotomy for repair of atrial septal defect.

Various surgical approaches for repair of atrial septal defect (ASD) have recently been introduced for superior cosmetic and less invasive results. A technique for repair of isolated ASD through a small right parasternal minithoracotomy is described. In spite of the smaller incision, there is no need to use femoral cannulation or video-assisted endoscopy. This approach is simple, less invasive, and cosmetic. We believe that right parasternal minithoracotomy is a suitable alternative to a median sternotomy for ASD closure, especially in young male patients.

Adolescent↗