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Biomedical subjects

M Nasu

Publications and source records attributed to M Nasu.

At least 163 records · Page 9Linked to original sources
PubMed1997

Serial evaluation of atrial function by Doppler echocardiography after the maze procedure for chronic atrial fibrillation.

The primary goal of the maze procedure is to prevent thromboembolism by restoring atrial function. We used Doppler echocardiography to evaluate the atrial function of patients who had undergone the maze procedure for the treatment of chronic atrial fibrillation. Thirty-five patients who converted to sinus rhythm after the maze procedure were enrolled in this study. Doppler echocardiography was performed in all patients in the early (mean, 19 days) and late (mean, 245 days) phases of the postoperative period. Left and right atrial active contraction fractions and left and right atrial storage fractions were calculated. The relationship between the pre-operative left atrial dimension and the left atrial active contraction fraction was evaluated in the late postoperative phase. The left atrial active contraction fraction was significantly increased in the late phase, but there was no change in the left atrial storage fraction. While the right atrial storage fraction was improved in the late phase, the right atrial active contraction fraction was increased even in the early phase. In patients with non-rheumatic mitral valve disease, a significant negative correlation was observed between the pre-operative left atrial dimension and the left atrial active contraction fraction in the late postoperative phase (r = 0.61; P < 0.05). However, no correlation between these parameters was observed in patients with rheumatic mitral valve disease. Atrial function was improved after the maze procedure. Serial difference were observed between left and right atrial function during recovery. Thus, in patients with non-rheumatic mitral valve disease, the left atrial dimension prior to the maze procedure may be useful in predicting the atrial contractile function postoperatively.

Atrial Fibrillation↗
PubMed1997

Long-term sequelae of experimental gastritis with Helicobacter pylori: a 5-year follow-up study.

To investigate the long-term effects of Helicobacter pylori gastritis on the gastric mucosa, 13 wild Japanese monkeys (six H. pylori-infected and seven controls) were monitored for 5 years. Colonization with H. pylori, the presence of macroscopic and histological gastritis, pyloric glandular height, and epithelial cell kinetics were investigated, using Ki-67 immunostaining in the gastric mucosa. In the infected group, persistent colonization with H. pylori was demonstrated by culture and histopathologic examination. In this group, the gastritis scores were significantly higher than in controls. Simultaneously, a significant decrease in the height of antral glands and a significant increase in the length of Ki-67-positive cells between the highest and lowest cells were also demonstrated in the infected animals. These experimental results directly demonstrate the effect of H. pylori infection on the gastric mucosa and may explain the potential mechanism for its causal role in the chain of events leading to gastric carcinoma.

Animals↗
PubMed1997

Virulence-associated genes as markers of strain diversity in Helicobacter pylori infection.

To establish a marker of strain diversity of Helicobacter pylori, a genetic examination was performed based on the detection rates by PCR of cagA and vacA, which are known to be virulence-associated genes. The test strains were obtained from 70 patients suffering from gastric ulcer (GU), 82 patients with duodenal ulcer (DU) and 48 patients with gastritis (GS). Fragments located in the three different regions of vacA were amplified; V1 being the upstream portion, V2 the mid-portion and V3 the downstream portion. For cagA, the detection rates were 70% for GU, 79% for DU and 50% for GS, showing a significantly higher rate for DU than for GS (P = 0.0005). With V1, the detection rates were 90% for GU, 90% for DU and 69% for GS, giving a significantly higher rate for GU than for GS (P = 0.0036) and also giving a significantly higher rate for DU than for GS (P = 0.0019). With V2, the detection rates were 60% for GU, 70% for DU and 44% for GS, giving a significantly higher rate for DU than for GS (P = 0.0024). The differences in vacA gene polymorphism were closely related to the evidence of gastroduodenal ulcers in H. pylori infection. Furthermore, the detection rates of cagA and polymorphisms of vacA by PCR could be used as markers of strain diversity in H. pylori-induced gastroduodenal ulcer.

Adult↗
PubMed1997

[A pathological study of cytomegalovirus infections in autopsied cases with adult T-cell leukemia].

In this study, cytomegalovirus (CMV) infection was found in eleven of 21 autopsied cases (52.4%) with adult T-cell leukemia (ATL). Seven cases (63.6%) revealed disseminated infection in more than three organs. The lungs were involved in all eleven cases (100%), adrenal glands in eight cases (72.7%), esophagus in four cases (36.4%), and stomach, small intestine and urinary bladder in three cases (27.3%). Histopathological findings suggested that lung involvement was the cause of death in five of the 11 cases, the small intestine were involved in two of the 3 cases, and the adrenal glands were involved in one of the 8 cases. In summary, CMV infection was found to be the main cause of death in five (45.5%) of the 11 ATL patients.

Adrenal Glands↗
PubMed1997

[Detection of Aspergillus species DNA in serum samples of the patients with non-invasive pulmonary aspergillosis].

We investigated the possible presence of Aspergillus species DNA in serum samples of two patients diagnosed as having non-invasive pulmonary aspergillosis by a nested polymerase chain reaction (PCR) method. The nested PCR results were negative in serum samples of the patients with chronic necrotizing pulmonary aspergillosis and pulmonary aspergilloma. When left pneumothorax happened to the patient with chronic necrotizing pulmonary aspergillosis and bronchial washing was performed to the patient with pulmonary aspergilloma, the nested PCR results turned positive. We consider this method useful for the diagnosis of semi-invasive stage of pulmonary aspergillosis. However, further prospective evaluation with a large clinical sample is required.

Aged↗
PubMed1997

[Immunodeficiency and carcinogenesis in patients with chronic active Epstein-Barr virus infection].

Three adult patients with chronic active Epstein-Barr virus infection (CAEBV) had high anti-EBV-VCA antibody, positive anti-EA, low anti-EBNA and were associated with systemic lymphadenopathies and immunosuppression. The case 1 and 2 had elevated serum immunoglobulin levels, and recurrent infections, and case 3 showed pancytopenia. These 3 cases developed both EBV and latent membrane protein (LMP) positive malignant histiocytosis, EBV positive but LMP negative plasmacytoma, and EBV negative acute myelogeneous leukemia, respectively. It was suggested that CAEBV belonged to high risk groups for the development of malignant neoplasms. Since HLA of the case 1 and his father was identical, we conducted a in vitro cytotoxicity test using EBV transformed autologous B lymphocytes, K562 cells, and Raji cells to clarify the association of immunosuppression and HLA. The case 1 showed a low level of specific cytotoxicity to autologous EBV transformed B cells, while his parents were negative for the specific cytotoxicity. The patient and his parents developed inducible cytotoxicity to all targets after in vitro incubation of peripheral mononuclear cells with recombinant interleukin 2 (rIL-2) for 7 days. The patient and his mother showed lower enhancement of cytotoxicity, while HLA identical father could induce good cytotoxic activity to all targets as well as normal controls, indicating that a low IL-2 induced cytotoxic activity observed in CAEBV was independent of HLA associated immunoregulation at least in the case 1. Further studies are required to clarify the exact mechanisms responsible for the development of CAEBV.

Adult↗
PubMed1997

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery.

OBJECTIVE: To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated. PATIENTS AND METHODS: Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram. RESULTS: Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01). CONCLUSIONS: The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

Adult↗
PubMed1997

Effect of antimicrobial agents on the piliation of Pseudomonas aeruginosa and adherence to mouse tracheal epithelium.

The effect of subminimal inhibitory concentrations (sub-MICs) of antimicrobial agents on the adherence of Pseudomonas aeruginosa (pili+) to trachea mucosal cells, the first stage in the development of P. aeruginosa respiratory tract infections, was investigated. The adherence of P. aeruginosa to the cells of the lower respiratory tract using a model of acid-injured trachea in mice was observed by electron microscopy (transmission and scanning). When P. aeruginosa was cultured with 1/4 MIC of erythromycin, minocycline, clindamycin, ofloxacin or tobramycin at 37 degrees C for 4 hours, the number of pili was significantly reduced (P < 0.01), together with a significant reduction in the number of adherent bacteria at 1/4 MIC of erythromycin (P < 0.01). No suppressive effects of piperacillin or ceftazidime were obtained on the piliation and adhesion of P. aeruginosa. These findings indicate that sub-MICs of erythromycin reduce the adherence of P. aeruginosa to the tracheal mucosa, which may prevent the onset of P. aeruginosa respiratory tract infection.

Animals↗
PubMed1997

Effect of natural menopause on serum levels of IGF-I and IGF-binding proteins: relationship with bone mineral density and lipid metabolism in perimenopausal women.

The present study was performed to examine the effect of natural menopause on serum levels of IGF-I, IGF-binding protein (IGFBP)-2 and -3 as well as on bone mass and lipid metabolism in perimenopausal women. One hundred and twenty-one healthy Japanese women, who were 45-55 years old, were studied (71 premenopausal and 50 postmenopausal women 1-9 years after menopause). Bone mineral density (BMD) was measured at the middle third of the radius by using dual energy X-ray absorptiometry. Serum levels of IGF-I, but not those of IGFBP-2 or -3, were significantly reduced in the postmenopausal group compared with the premenopausal group. One year after menopause, serum IGF-I levels were significantly lower, and the biochemical markers of bone turnover, such as serum total alkaline phosphatase level and urinary calcium to creatinine ratio, were significantly higher than the premenopausal levels. Serum levels of IGF-I, but not those of IGFBP-2 or -3, were positively correlated with BMD. Serum levels of IGFBP-2, but not those of IGF-I or IGFBP-3, were negatively correlated with body mass index and body weight. Finally, serum levels of IGFBP-3, but not those of IGF-I, were positively correlated with serum levels of total cholesterol and triglyceride. The present findings suggest that a rapid decrease in serum IGF-I levels after menopause might be partly involved in bone loss following gonadal failure and that IGFBP-2 and -3 might be related to the regulation of body mass and lipid metabolism during perimenopause respectively, although the mechanisms remain unknown.

Bone Density↗
PubMed1997

Optical imaging of neural activity in auditory cortex induced by intracochlear electrical stimulation.

Little is known about the representation of electrically evoked activity in the auditory cortex. We observed evoked activity in guinea pig auditory cortex evoked by acoustical and electrical stimulation to the cochlea by optical imaging with the aid of a voltage-sensitive dye. Light signals from the cortex were recorded with a 12 x 12 array of photodiodes, and transferred to the spatio-temporal images by every 0.57 ms. The activity by pure tones was shown spatio-temporally through tonotopical organization in the cortex according to the sound frequencies. The tonotopic responses were dynamically changed. When the cochlea was stimulated with single electrical pulses, focal activities were observed in the cortex as spatio-temporal patterns. Activated cortical regions were not sharply localized, but varied with stimulating positions of the cochlea. The curves of response magnitude versus stimulus intensity showed the narrow dynamic range, and that of latency was almost constant. These results were significantly different from those for normal sound stimulation.

Acoustic Stimulation↗
PubMed1997

[Direct in situ PCR method for the detection of verotoxin-producing Escherichia coli].

Rapid detection of verotoxin-producing Escherichia coli at a single-cell level under an epifluorescence microscope without culturing processes was accomplished by using the direct in situ PCR technique. We used a DNA primer set for amplification of the slt-I and slt-II genes encoding respectively verotoxin 1 and 2 (EVT and EVS primers). The bacterial cells were detected specifically by the HNPP (2-hydroxy-3-naphthoic acid-2'-phenylanilide phosphate)/Fast Red TR reaction technique. The direct in situ PCR with HNPP/Fast Red TR technique is applicable to the detection of verotoxin-producing bacteria with the slt-I or slt-II gene in not only Escherichia coli O157 but also VTEC of other serotypes.

Bacterial Toxins↗
PubMed1997

Genotyping of hepatitis C virus in the Dominican Republic.

Genotyping of hepatitis C virus (HCV) of liver disease patients in the Dominican Republic was performed. Eighty-four samples positive for HCV antibody, which were confirmed by ELISA, particle agglutination, and recombinant immunoblot assay III tests, were subjected to HCV genotyping by polymerase chain reaction using type-specific primers located in the nonstructural protein 5 region. Of the 84 samples tested, 50 (59%) were found to have genotype 1a/I and this genotype was the most frequent type detected in the present study. The numbers of isolates of genotypes 1b/II, 2a/III, 2b/IV, and 3a/V were three (3.6%) six (7.1%), two (2.4%), and two 2.4%), respectively. The number of samples having mixed genotype populations was 16 (19%). The possible causes of the high prevalence of genotype 1a/I in the Dominican Republic compared with other countries and of the high detection ratio of samples having mixed genotypes are discussed.

Agglutination Tests↗
PubMed1997

Can the maze procedure be combined safely with mitral valve repair?

BACKGROUND AND AIMS OF THE STUDY: The safety of combining mitral valve repair with the maze procedure for chronic atrial fibrillation in the surgical management of patients with mitral valve disease is not well elucidated. We present our operative results regarding mortality and morbidity after such combined surgery. As a comparison, our operative results after mitral valve repair in patients without chronic atrial fibrillation are presented. METHODS: Between April 1993 and December 1994, 39 patients with chronic atrial fibrillation underwent mitral valve repair and concomitant maze procedure (group 1) at the Iwate Medical University. During the same period, 36 patients with sinus rhythm and one patient with DDD pacemaker underwent mitral valve repair (group 2). In order to evaluate the operative risk, morbidity, and mortality of adding the maze procedure to mitral valve repair, total cardiopulmonary bypass time, aortic cross-clamp time, intraoperative blood loss, intubation period, and duration of ICU stay were compared between the groups. RESULTS: Total cardiopulmonary bypass time and aortic cross-clamp time in group 1 were longer than in group 2 (174.0 +/- 38.8 min versus 150.1 +/- 54.4 min; p = 0.032, 122.5 +/- 30.7 min versus 95.8 +/- 38.2 min; p = 0.0012). However, the duration of ICU stay, intubation period, and intraoperative blood loss were not different between the groups. There were no hospital deaths in either group. Four patients in group 1, and two patients in group 2 required re-exploration for bleeding (p = NS). Two patients in group 1, and none in group 2 required pacemaker implantation postoperatively (p = NS). Two patients in group 2, and none in group 2 had minor cerebral infarction (p = NS). At hospital discharge, 28 patients in group 1 (72%) and 35 patients (97%) in group 2 were in sinus rhythm. CONCLUSIONS: The maze procedure can be combined with mitral valve repair without adding undue operative risk to patients. Those patients with chronic atrial fibrillation undergoing mitral valve repair may be advised for the possibility of concomitant maze procedure.

Aged↗
PubMed1997

[Diffuse alveolar hemorrhage associated with idiopathic interstitial pneumonia syndrome after allogeneic bone marrow transplantation].

A 24-year-old male with myelodysplastic syndrome (refractory anemia) was treated with allogeneic bone marrow transplantation (BMT) from HLA-identical brother on September 9, 1994, after conditioning with busulfan and cyclophosphamide. From early in April 1995, the patient complained of cough and fever. Chest X-ray showed interstitial infiltrates involving hilar and lower lung fields. Although pulmonary infiltrates were resolved with methylprednisolone pulse therapy, on May 19, the patient rapidly deteriorated with dyspnea. Diffuse alveolar infiltrates appeared on chest X-ray and he died of respiratory failure. At autopsy, diffuse alveolar hemorrhage accompanied with thickening of the alveolar walls and interstitial infiltration of lymphocytes was demonstrated. There was no evidence of bleeding in other organs. This is a rare case of diffuse alveolar hemorrhage in the late stage of allogeneic BMT. This report should lead to an evaluation of this disease by the collection of similar cases.

Adult↗
PubMed1997

[The case of left atrial myxoma originating from posterior leaflet of mitral valve].

We experienced the case of left atrial myxoma originating from posterior leaflet mitral valve. Mitral valve repair was performed in that case, because of the presence mitral leaflet defect due to removal of the myxoma. Transesophageal echocardiography was a useful tool for perioperative evaluation of the mitral valve and precise localization of the origin of the myxoma.

Adolescent↗
PubMed1997

Hepatoid carcinoma of the lung with production of alpha-fetoprotein and abnormal prothrombin: an autopsy case report.

Alpha-fetoprotein (AFP) is a useful tumor marker for the diagnosis of hepatic and testicular tumors. Several cases of AFP-producing lung cancer have been reported. We present here a patient with AFP-producing primary lung carcinoma, which showed high values of serum AFP (100,000 ng/mL). The concanavalin A nonbinding fraction rate of AFP was 15%. Gross and microscopic features of the lung carcinoma bore a striking resemblance to those of hepatocellular carcinoma. According to the histologic classification of lung tumor, this case was large cell carcinoma with prominent hepatoid differentiation. Immunohistochemically, we detected AFP in the cytoplasm of the neoplastic cells. We also detected another useful tumor marker for the diagnosis of hepatocellular carcinoma, i.e., des-gamma-carboxy prothrombin (protein induced by vitamin K absence or the absence of antagonist-II [PIVKA-II]), in serum using an enzyme immunoassay and in tumor cells by immunohistochemical analysis.

Biomarkers↗