Biomedical subjects

T Tabata

Publications and source records attributed to T Tabata.

At least 199 records · Page 11Linked to original sources

PubMed1994

Reduction of homologous blood transfusion in reoperative valve surgery.

From April 1979 to October 1993, 126 adult patients underwent reoperative cardiac valve surgery. Patients were divided into two groups: 53 patients who underwent surgery before January 1990 (group 1) and 73 patients who underwent surgery after January 1990 (group 2). After January 1990, a clinical strategy for reducing homologous blood transfusions was implemented, including the use of predonation of autologous blood in the operating room, reduced heparin doses, an elevated threshold of indication for blood transfusion, and autotransfusion of shed, drained blood after surgery. In group 1, 44 patients (93.0%) received an average of 3785 +/- 1251 ml of homologous blood transfusions. In group 2, only 26 patients (35.6%) needed homologous blood transfusions and had a smaller amount (2985 +/- 1521 ml) on average. Furthermore, only seven patients needed fresh blood transfusion in group 2.

Adult↗

PubMed1994

[Effect of amurinone on human pulmonary artery in vitro].

We studied the effect of amurinone, a phosphodiesterase inhibitor, on human pulmonary arterial smooth muscle in vitro. Amurinone caused dose-dependent relaxation of pulmonary arterial strips precontracted with 60 mM KCl. Preincubation with either meclofenamate (31 microM), a cyclooxygenase inhibitor, or L-NG-nitroarginine (100 microM), an endothelium-derived relaxing factor (EDRF) production inhibitor, failed to inhibit amurinone-induced pulmonary vasodilation. The cyclic AMP (cAMP) levels in the supernatant of the lung vessel homogenates significantly increased after incubation with amurinone. These results indicate that amurinone causes relaxation of human pulmonary artery in vitro, and suggest a role for cAMP in the mechanisms of amurinone-induced pulmonary vasodilation.

Adult↗

PubMed1994

Comparative phonocardiographic, echocardiographic and Doppler echocardiographic evaluation of normally functioning Medtronic Hall and Björk-Shiley mitral prosthetic valves.

Although data from cardiac catheterization and in vivo studies are available, phonocardiographic and ultrasonic characteristics of the Medtronic Hall valve in the mitral position have not been adequately established. Phonomechanocardiographic, echocardiographic and Doppler echocardiographic examinations were performed in 15 patients (Medtronic Hall group) with a Medtronic Hall mitral valve prosthesis to elucidate the phonocardiographic and ultrasonic characteristics of the normally functioning Medtronic Hall valve in the mitral position. These findings were compared with those obtained from 20 patients (Björk-Shiley group) with a normally functioning Björk-Shiley 60 degrees mitral valve prosthesis. Simultaneous recordings of the phonocardiogram and M-mode echocardiogram of the prosthetic valve in patients in the Medtronic Hall group revealed three opening clicks relating to disc motion. The timing of the three opening clicks correlated with the onset of disc opening, the completion of disc opening, and a notch which appeared about 30 msec after the completion of disc opening. Similar recordings performed in patients in the Björk-Shiley group revealed that the third opening click was detected in only half of the patients and that its timing was nearly twice as early as that noted in the Medtronic Hall group. The Medtronic Hall group had significantly shorter durations of the apical diastolic rumble and the slow filling wave on the apexcardiogram, as well as significantly reduced peak mitral inflow velocity during early diastole and shortened pressure half-time on the mitral inflow velocity curve. Transesophageal Doppler echocardiography demonstrated slight mitral regurgitation in all patients in both the Medtronic Hall and the Björk-Shiley groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Acute renal failure associated with minimal change nephrotic syndrome in an elderly adult.

We report a 66-year-old man with minimal change nephrotic syndrome (MCNS) that was associated with reversible acute renal failure (ARF) caused by acute tubular necrosis (ATN). He had a subacute onset of proteinuria and progressive azotemia. Hemodialysis (HD) was required to improved azotemia. Renal biopsy revealed minor glomerular abnormalities associated with ATN. While continuing HD, steroid therapy was started, which subsequently allowed the patient to be weaned from HD and relieved from NS. In this patient, histological examination and clinical course suggested that ATN was probably induced by hypovolemia due to MCNS.

Acute Kidney Injury↗

PubMed1993

The role of Ras mutation in pancreatic cancer, precancerous lesions, and chronic pancreatitis.

Point mutations in K-ras codon 12 were detected in 7 of 10 specimens (70%) of frozen tissues. To determine when point mutations appear in the oncogenic stage, paraffin-embedded tissues of pancreatic cancer, hyperplastic ductal lesions in pancreatic cancer and in chronic pancreatitis were used. DNA extracted from the paraffin-embedded tissues classified as cancer, atypical and nonatypical hyperplasia of the pancreatic duct epithelium, and normal tissue from pancreatic cancer patients and those classified as atypical hyperplasia of the pancreatic duct epithelium and normal tissue from chronic pancreatitis patients were amplified by the polymerase chain reaction (PCR) method. Point mutations were detected in 8 of 17 cancer cases (47.0%). In 5 of 8 point mutation positive cases, atypical hyperplasias were found in the surrounding tissues. In all 5 of these atypical hyperplasia, point mutations, that is, GGT-GTT (Gly-Val) and GGT-GAT (Gly-Asp), were detected. The same transitions were observed in the cancer of these 5 cases. These results suggest a strong relationship between cancer and atypical hyperplasia surrounding cancer. Although atypical hyperplasia around cancer was histologically very similar to that found in chronic pancreatitis, all 5 atypical and 5 nonatypical hyperplasias in chronic pancreatitis were negative for ras point mutation. Thus, the result argues against an association between chronic pancreatitis and pancreatic cancer.

Adult↗

PubMed1993

Effect of tooth temperature on activities of slowly adapting periodontal mechanoreceptors during or after long-lasting strong pressure applied to the cat upper canine tooth.

Periodontal mechanosensitive units (PM units) responsive to mechanical stimulation of this tooth were recorded from single fibres isolated from the superior alveolar nerve. Mechanical stimulation was applied in a sequence of long-lasting strong pressure followed by a train of weak stimuli. Temperature was changed by perfusing the pulpal cavity of the stimulated tooth with saline solution at a temperature of 5-45 degrees C. The response of the PM units elicited by strong pressure was initially dynamic and subsequently static. The dynamic response was little affected by tooth temperature whereas, the static response increased with the rise in temperature. After strong pressure the excitability of the PM units was depressed transiently, followed by gradual recovery; this depression was especially prominent when tooth temperature was high.

Animals↗

PubMed1993

Study on the efficacy of biodegradable poly(L-lactide) mesh for supporting transplanted particulate cancellous bone and marrow: experiment involving subcutaneous implantation in dogs.

Poly(L-lactide) (PLLA) mesh sheets, monofilaments and mesh cylinders filled with fresh autogenic particulate cancellous bone and marrow (PCBM) were implanted subcutaneously into the back of 22 adult dogs for 1 yr. Polypropylene (PP) was used as a control. The inflammatory response to PLLA mesh sheets was slight, similar to PP mesh sheets. However, 3 months after implantation, histiocytes and multinucleate giant cells appeared on the surface of the monofilaments of PLLA mesh sheets and gradually increased in number as the monofilaments were degraded and absorbed. Almost no inflammatory cellular infiltration was seen in the tissue around PLLA mesh sheets or between the monofilaments. When a PLLA mesh cylinder filled with PCBM was implanted subcutaneously, the bone formation reached its peak 1 month after implantation, as in the case of a similar PP mesh cylinder, and bone formation was observed along the inner wall of the cylinder. In addition, a vascular net was abundant within the cylinder. The mechanical strength of the test material (PLLA monofilaments) did not change for almost 2 months after implantation, and 80% of its initial strength was retained for 3 months. These observations suggest that a PCBM graft supported by PLLA mesh would be very effective in the reconstruction of damaged maxillofacial bones, since histological tissue reactions associated with biodegradation of the PLLA mesh are mild and the PLLA mesh does not interfere with bone formation of PCBM. It was also found that the PLLA mesh retains its mechanical strength long enough to allow the PCBM transplant to develop sufficient strength to sustain the damaged region.

Animals↗

PubMed1993

Detection of Haemophilus influenzae in middle ear of otitis media with effusion by polymerase chain reaction.

Otitis media with effusion (OME) is one of the major causes of hearing loss in childhood. The pathogenesis still remains unclear, though it is closely related to acute otitis media with bacterial infections. It is known that Haemophilus influenzae is one of the most common bacteria isolated from middle ear effusions (MEEs). Recently, in vitro DNA amplification by polymerase chain reaction (PCR) is a new technology that has considerable implication for diagnosis of viral and bacterial infections because of its potentially precise specificity and sensitivity. In the present experiment polymerase chain reaction (PCR) was applied to the detection of DNA genome of H. influenzae contained in middle ear effusions. By Southern blot hybridization, two characteristic bands for H. influenzae DNA were detected at 273 b.p. and 550 b.p. position in 15 of 27 MEEs. However, no organism was cultured by conventional methods. Our results indicate the PCR technique is more specific and sensitive in detection of bacteria in middle ear effusion of OME, compared with conventional methods. It strongly suggests more involvement of the bacteria, especially H. influenzae, in OME onset.

Child↗

PubMed1993

Genesis of the Austin Flint murmur: relation to mitral inflow and aortic regurgitant flow dynamics.

OBJECTIVES: This study was designed to elucidate the genesis of the Austin Flint murmur. BACKGROUND: The Austin Flint murmur is an apical diastolic rumble associated with significant aortic regurgitation. The precise mechanism of the murmur remains unclear. METHODS: The relation between the Austin Flint murmur and mitral inflow and aortic regurgitant flow dynamics was evaluated nonivasively in 13 patients with moderate to severe aortic regurgitation and 15 control subjects using phonocardiographic and pulsed and color-coded Doppler echocardiographic techniques. The severity of aortic regurgitation was determined by color-coded Doppler echocardiography on the basis of the maximal distance of the regurgitant signal. RESULTS: The direction of aortic regurgitant flow was unrelated to the presence of the Austin Flint murmur. The severity of aortic regurgitation was greater in patients with than in those without this murmur. The peak mitral inflow velocity during early diastole (E) was significantly increased, and both peak mitral inflow velocity at atrial contraction (A) and the A/E ratio were significantly decreased in patients with the Austin Flint murmur compared with values in those without this murmur or in control subjects. However, the maximal amplitude of the Austin Flint murmur did not coincide temporally with the peak mitral inflow velocity. The murmur continued both after rapid mitral inflow had ended and during diastolic mitral regurgitation. CONCLUSIONS: The increased velocity of early diastolic mitral inflow in patients with the Austin Flint murmur is due to aortic regurgitation, but rapid mitral inflow is not an essential requirement for production of the murmur. In some cases, the Austin Flint murmur may be generated by aortic regurgitant flow alone.

Adult↗

PubMed1993

Segmentation of the Drosophila embryo.

Segmentation in Drosophila is a sequential process directed by at least 30 genes that encode various types of proteins, including: many transcription factors; a putative RNA-binding protein; a membrane-associated receptor kinase; several intracellular protein kinases; a number of secreted signaling molecules; and others of unknown function. Although the detailed molecular reactions used to generate the metameric subdivisions of the embryo are not yet understood, a general outline of the processes involved has been described. The manner in which spatial relations in the developing embryo are established can now be described.

Animals↗

PubMed1993

Antibody synthesis to peptidoglycan polysaccharide after ischemic injury of the intestine.

BALB/c mice (ischemia: 31; controls: 15) were studied to investigate the effects of intestinal ischemia on antibody synthesis to peptidoglycan polysaccharide (PGPS), a ubiquitous bacterial antigen found in both gram-positive and gram-negative bacteria. The gut ischemia model was produced by placing a vessel loop around the superior mesenteric vessels for 45 minutes. All animals in the ischemia group had visible gut ischemia. Eighteen animals (58%) in the ischemia group survived to 24 hours and all experienced total recovery of gut viability. Single-cell suspensions of splenic lymphocytes were made. After 5 days of culture with lipopolysaccharide, anti-PGPS immunoglobulin concentrations in culture supernatants were measured by ELISA using high-titer BALB/c anti-PGPS serum as control. The synthesis of immunoglobulin by 10(5) lymphocytes was significantly increased in the ischemia group compared with the controls. These results represent the translocation of bacteria after intestinal ischemia, and this antibody response may be important in resistance to sepsis and multiple organ dysfunction attributed to bacterial translocation.

Animals↗

PubMed1993

Effects of burn injury on class-specific B-cell population and immunoglobulin synthesis in mice.

Mice of the C57BL/6 strain were studied to investigate the effects of a 20% total body surface area full-thickness burn on class-specific immunoglobulin synthesis. Five days after injury single cell suspensions of spleen and mesenteric lymph node cells were made. The number of class-specific immunoglobulin-bearing cells were counted by flow cytometry using Texas-red-labelled antibody to class-specific mouse immunoglobulin. The remaining cells were cultured with lipopolysaccharide for 4 days. The supernatant was tested for class-specific immunoglobulin by enzyme-linked immunosorbent assay (ELISA). There was no change in the number of class-specific IgG and IgA lymphocytes, but there was a significant increase in IgM lymphocytes. Synthesis of immunoglobulin by 10(5) lymphocytes was significantly increased in IgG and IgA cells, but decreased in IgM cells. Similar results were shown in spleen and mesenteric lymph node cells. Because the IgM response was much greater than others in the number of cells and immunoglobulin synthesis, we conclude that the decrease in responsiveness of IgM may contribute significantly to increased host susceptibility to infection after burn.

Animals↗

PubMed1993

Genotypic analysis of Epstein-Barr virus associated with nasopharyngeal carcinoma of Japanese patients.

Types and certain genetic markers were studied for Epstein-Barr virus present in 10 specimens of nasopharyngeal carcinoma (NPC) from Japanese patients. The type 1 virus was predominant in our NPC specimens, as in the general Japanese population, and the type 2 virus was found only in one NPC specimen. The type C variant, which lacks the BamHI site between the BamHI-W1* and -I1* regions, appeared to be common among Japanese strains as in those in Southern China. The type f variant which has an extra BamHI site in the BamHI-F region and has been shown to be strongly associated with NPC in Southern China was found in only one NPC specimen. This virus strain was also the only type 2 virus among our specimens. The present study, therefore, does not show any specific association of the type f variant with NPC in Japan.

Adult↗

PubMed1993

Differences in the mode of cough augmentation by four angiotensin-converting enzyme inhibitors in guinea-pigs.

The effects of four angiotensin-converting enzyme (ACE) inhibitors, captopril, enalapril, quinapril and alacepril, on the cough responses caused by citric acid and capsaicin inhalation were studied in normal and bronchitic guinea-pigs. After an oral dose of 10 mg kg-1, none of the ACE inhibitors had an effect on the citric acid-induced coughing response in normal guinea-pigs. Enalapril 10 mg kg-1 significantly increased the number of coughs caused by capsaicin inhalation. In bronchitic guinea-pigs, 10 mg kg-1 captopril and enalapril significantly increased the number of capsaicin-induced coughs. When administered daily for 8 days, captopril was the only ACE inhibitor which significantly increased the number of coughs due to citric acid inhalation. The present results indicate that the ACE inhibitors had different modes of cough augmentation.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1993

A Ki-1-positive cell line expressing Epstein-Barr virus antigens, established from a child with Ki-1-positive lymphoma.

We report here the establishment of a CD30 (Ki-1) antigen-positive cell line 'Ki-JK' from a child with anaplastic large cell lymphoma. We characterized this cell line and show that: (i) Ki-JK cells do not grow in soft agar but infrequently produce a tumor or suppressed growth when injected into nude mice; (ii) Ki-JK cells expressed Epstein-Barr virus (EBV) antigens, EBV-associated nuclear antigen-2 and latent membrane protein; (iii) Ki-JK cells are labelled by in situ hybridization using an RNA probe derived from the BamHI W fragment of EBV, and (iv) polymerase chain reaction demonstrates the presence of an EBV BamHI W sequence in DNA of lymphoma and Ki-JK cells. These results suggest an etiological role for EBV in the development of some cases of Ki-1-positive lymphomas.

Adolescent↗

PubMed1993

Assessment of left ventricular diastolic function and potential by quantitative analysis of left ventricular filling curves in patients with atrial fibrillation. A new algorithm for Doppler echocardiographic study.

To evaluate left ventricular (LV) diastolic function and potential, LV filling curves for 18 patients with atrial fibrillation (Af) were constructed and their positions and appearance were evaluated quantitatively by analysis of 95% maximal filling volume points and maximal curvature alteration points. The LV filling curves of group A (Af only) lay left superiorly, while those of group B (impaired LV diastolic function) were situated right inferiorly, all bending steeply. The LV filling curves of group C (mitral stenosis) bent slightly. The lowest normal filling volume points and compensation areas were calculated to evaluate LV diastolic function and were demonstrated to be very different in groups A and B. The lowest normal filling volume points of group C were similar to those of group A, but compensation areas were smaller, indicating a lower LV diastolic potential. It is concluded that the 95% maximal filling volume point, maximal curvature alteration point, lowest normal filling volume point and compensation area are effective indices for evaluating not only LV diastolic function but also the diastolic potential.

Algorithms↗

PubMed1993

Clinical evaluation of two-piece apatite dental implants in 189 cases.

A two-piece apatite implant composed of a titanium abutment and a titanium tubular root portion cemented to an outer dense hydroxyapatite (D-HAP) tubular shell by resin cement has been authorized as High Advanced Medical Technology (H.M.A.T.) and applied since December 1987. We will show the success rate and the evaluation of the implants applied through May 1992. A successful implant was considered as one that provides functional comfort with no mobility and the absence of surrounding mucosal inflammation. The number of implants applied during the last 4.5 years was 810 pieces in 189 cases with an overall success rate of 92.5% for the 704 implants with abutment. The extirpation rate has no clear linear association with the duration of the implant or with the patient's age. Most of the extirpations resulted from cases where the patient used a provisional denture during the bone healing period, the time between implantation and abutment cementation. Extirpation rate of implant was high in cases using large maxillary provisional dentures with ten or more missing teeth. It is believed that all implant cases in which large dentures were used frequently contributed to the extirpation. These observations led us to suggest that provisional dentures may be harmful to the implant. When we shifted from the traditional method to the Delay Method 2.5 years ago, no incidence of extirpation was experienced in the mandible, even with the use of provisional dentures. In the maxilla, the Delay Method proved to be effective without the provisional denture. However, the results of the Delay Method with provisional dentures remains to be evaluated. The reason is that too few cases were encountered with large missing teeth to suffice for our observation. This Delay Method (named by us) consists of delaying the insertion of the implant for approximately 2 months after the first socket preparation, until the bone tissue activity has risen. After some adjustment in the prepared socket, the implant is then inserted during the second surgical procedure. We therefore consider this method of potential benefit over the traditional method.

Aged↗

PubMed1993

Tissue response of apatite-filled resin cement and titanium-reinforced apatite dental implants in dogs.

Abutment and root portion divided two-piece dental implants were designed to modify the one-piece dense hydroxyapatite (D-HAP) implant. The initial placement of the root portion endosseously ensured an aseptic environment and physical stability for the implant during the bone healing period. The outer D-HAP shell of the root portion was fortified by an inner titanium cylinder and cemented with an adhesive resin cement containing 4-methacryloyoxyethyl trimellitate anhydride (4-META) and reinforced by fine apatite filler. Upon attaining integration of the bone and implant, the abutment was screwed and fixed into the screw hole of the root portion. The tissue response of both the apatite-filled resin cement and root portion of the two-piece implant was studied by animal canine experiments. Light and electron microscopic examination of specimens taken from experimental animal tissue showed bone contacted directly not only the exposed apatite filler at the surface of the apatite-filled resin cement, but also the resin portion. These findings of direct bone contact suggested that the tissue response of apatite-filled resin cement was approximately similar to the usual D-HAP. Because most of the surface of the outer D-HAP shell of the root portion came in contact with bone, it prevented the deposition of contamination on the D-HAP surface during the manufacturing procedures of the root portion.

Animals↗