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Biomedical subjects

M Nasu

Publications and source records attributed to M Nasu.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Aortic valve papillary fibroelastoma in a patient with mitral valve regurgitation].

Papillary fibroelastoma is a rare cardiac tumour. We describe a patient with mitral valve regurgitation and aortic valve papillary fibroelastoma. The patient was 62-year-old woman. She was referred to us for surgical treatment of mitral valve. Preoperative echocardiography showed rheumatic mitral valve regurgitation (Sellers grade III) and it also demonstrated mobile masses of the aortic valve. At operation, mitral valve was repaired by a posterior annuloplasty. Through the aortotomy, small tumors were found to be attached to each cusps of the aortic valve and they were successfully removed. The histopathologic diagnosis was papillary fibroelastoma of the aortic valve. The postoperative course was uneventful.

Aortic Valve↗
PubMed1999

Divergence of virulence factors of Helicobacter pylori among clinical isolates does not correlate with disease specificity.

The aim of this study was to examine the relation between disease specificity and the virulence factors of Helicobacter pylori isolated from patients with gastric cancer (GC), duodenal ulcer (DU), and gastritis (GS). Altogether 18 isolates obtained from patients with GC, 28 isolates from DU patients, and 13 isolates from GS patients were analyzed. All isolates were tested for the presence of the cagA gene, and genotyping of the vacA gene was done by the polymerase chain reaction. Production of VacA protein and expression of vacuolating cytotoxic activity in the H. pylori culture supernatant were examined. The serum antibody titers against purified VacA and CagA proteins were determined by enzyme-linked immunosorbent assay (ELISA). Interleukin-8 (IL-8) production by AGS cells in response to H. pylori isolates was measured by an hIL-8 ELISA kit. Genetic analysis of vacA revealed that most of the clinical isolates were classified into the S1a type by signal sequence typing. There were no differences in cagA detection rates, vacuolating cytotoxin activity, or mean antibody titers against VacA and CagA protein among the three groups. The mean IL-8 concentrations in the supernatants of AGS cells were similar in the three groups. In this study, there was no difference in virulence factors of H. pylori among isolates from GC, DU, and GS.

Antigens, Bacterial↗
PubMed1999

Evidence for viability of coccoid forms of Helicobacter pylori.

It is an open question whether the coccoid form of Helicobacter pylori is alive in the dormant state or is degenerative and in the process of cell death. We studied the viability of the coccoid form of H. pylori to explore the possibility of infectivity to the host by evaluating its protein synthesis and acid response. Coccoid H. pylori conserved the capability to produce proteins for at least 100 days when stored at 4 degrees C in either phosphate-buffered saline (PBS) or distilled water. After 20 days of storage in distilled water exposure of the coccoids obtained to acidic pH induced expression of the several proteins but inhibited those induced after 20 days of storage in PBS. However, after extending the incubation of the coccoid forms in PBS up to 100 days, the organisms acquired the ability to induce the proteins in response to acid stress. The induction of protein expression may be involved in the biological event of transformation into the spiral form. Furthermore, this altered response of the coccoids to acid shock may determine the potential for morphological reversion during incubation.

Bacterial Proteins↗
PubMed1999

What are the predictors of restoration of sinus rhythm after combined treatment with surgical repair for organic heart disease and the Maze procedure for atrial fibrillation?

BACKGROUND: Recently, combined treatment using the Maze procedure for organic heart disease and atrial fibrillation has been reported, but there have been few studies of cardiac rhythm after combined treatment. Predictors of cardiac rhythm after combined surgical treatment have been unknown. METHODS: Thirty patients who underwent cardiac surgery with the Maze procedure were retrospectively enrolled in this study. Two groups consisted of the patients with restoration of sinus rhythm after surgery (SR: n=15, 6 males and 9 females, mean age of 64 years), and the patients with maintenance of atrial fibrillation (AF; n=15, 5 males and 10 females, mean age of 61 years). Before cardiac surgery, all patients underwent exercise testing with measurement of atrial natriuretic peptide (ANP) before and after exercise testing, two-dimensional echocardiography, and right and left heart catheterization. RESULTS: The mean maximal heart rate and the ANP level after exercise testing in SR were significantly higher than those in AF. The left atrial dimension and right atrial and pulmonary capillary wedge pressures were significantly higher in AF than in SR. These findings indicate that subjects in SR exhibited less impaired atrial function which were evaluated by exercise testing with measurement of ANP, echocardiography, and cardiac catheterization. CONCLUSIONS: The atrial function of patients with sinus rhythm after the Maze procedure may be less impaired than that of patients remaining in atrial fibrillation.

Aged↗
PubMed1998

Anisotropic neural interaction in the primary auditory cortex of guinea pigs with sound stimulation.

Neural interaction in the primary auditory cortex of guinea pigs anesthetized with sodium pentobarbital was studied using a single line multi-electrode (4 x 1) aligned across and along the isofrequency band. Under the spontaneous condition, the neural interaction was isotropic; the amplitude of cross-correlogram peaks decreased as the electrode separation increased both across and along the isofrequency band. Under tone stimulation, the neural interaction was anisotropic; the amplitude of peaks was decreased rapidly beyond 400 microm across the isofrequency band, while it decreased little up to 700 microm along the isofrequency band. This anisotropic interaction was dependent on the stimulus intensity.

Acoustic Stimulation↗
PubMed1998

Development of Helicobacter pylori-induced gastric carcinoma in Mongolian gerbils.

Helicobacter pylori is classified by IARC/WHO as a definite human gastric carcinogen, despite "inadequate experimental evidence." To obtain direct evidence concerning this relationship, we investigated the histopathological findings of gastric mucosa using a model of H. pylori infection in Mongolian gerbils. The animals were challenged p.o. with H. pylori ATCC-43504 and sacrificed at 6, 12, and 18 months after inoculation for histological examination. All inoculated animals were infected with H. pylori. Severe infiltration of the lamina propria by polymorphonuclear and mononuclear cells appeared in the lesser curvature of the antrum, with an increase in epithelial cell proliferation, and the infiltration extended to the body. Atrophic gastritis and focal intestinal metaplasia also appeared in the lesser curvature of the antral mucosa at 6 months after inoculation. Intestinal metaplasia became severe, with dysplasia, after that. At 18 months after H. pylori inoculation, two of five infected animals showed three well-differentiated gastric cancers. The uninfected control animals showed no abnormal findings throughout the entire observation period. Here, it was confirmed that H. pylori infection alone causes gastric cancer in an animal model.

Animals↗
PubMed1998

Optical recording of responses to frequency-modulated sounds in the auditory cortex.

Using an optical recording method with a voltage-sensitive dye, we recorded activities in the primary auditory cortex (AI) of anesthetized guinea pigs in response to frequency-modulated (FM) sounds and sounds with stepwise changes in frequency (SF). Responses to the FM sound showed a spatiotemporal pattern in which a localized active spot traversed the isofrequency bands in the AI, and they differed from the band-like responses to the SF sound. These results indicate that time-varying sounds are represented as spatiotemporal activation of tonotopic organization in the AI by spectral cues with interactions between frequency bands.

Acoustic Stimulation↗
PubMed1998

Eosinophilia associated with adult T-cell leukemia: role of interleukin 5 and granulocyte-macrophage colony-stimulating factor.

To clarify the mechanism of eosinophilia in adult T-cell leukemia (ATL), we studied three ATL patients having marked eosinophilia. Eosinophil-predominant colony-stimulating activity was detected in the serum of one patient and in the conditioned media (CM) from cultured ATL cells from two patients. Soluble interleukin 5 (IL-5), but no interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), was detected in sera from all patients. On the other hand, GM-CSF was produced in vitro by ATL cells from all cases, whereas detectable IL-3 and IL-5 was produced by cells from only one, suggesting that in the other two cases, the serum IL-5 was produced by the normal reacting lymphocytes. The fact that no patient showed marked neutrophilia supports the possibility that IL-5 may have a leading role in the development of eosinophilia, with GM-CSF produced by ATL cells playing a complementary role.

Aged↗
PubMed1998

Flow dynamics of angiographically no-flow patent internal mammary artery grafts.

OBJECTIVES: This study sought to assess the flow dynamics of internal mammary artery grafts (IMAGs) in no-flow situations by use of a Doppler guide wire. BACKGROUND: Functionally no-flow and anatomically patent IMAGs have been reported by angiography in patients with a patent recipient coronary artery. METHODS: The study included 12 patients with an IMAG to the left anterior descending coronary artery (LAD) in whom no-flow patency of the graft was suspected angiographically. Thirteen patients with a normally functioning IMAG whose LAD was occluded in the proximal portion and was supplied only from the graft served as control patients. Phasic flow velocities were recorded in the distal portion of the graft and the recipient LAD using a 0.014-in., 15-MHz Doppler guide wire at rest and during hyperemia (0.14-mg/kg body weight per min intravenous adenosine infusion). RESULTS: There were no significant differences in systolic (15+/-3 vs. 19+/-6 cm/s, p = NS), diastolic (35+/-11 vs. 37+/-7 cm/s, p = NS) and time-averaged peak velocities at rest (20+/-5 vs. 21+/-5 cm/s, p = NS), during hyperemia (51+/-12 vs. 54+/-8 cm/s, p = NS) and in coronary flow velocity reserve (2.8+/-0.9 vs. 2.7+/-0.3, NS) in the native LAD in patients with a no-flow patent graft versus control patients. Within the graft, to and fro signals with systolic reversal and diastolic anterograde flow were seen in the no-flow patent grafts, although anterograde flow signals were recorded in systole and diastole in control patients. Systolic (-28+/-19 vs. 22+/-9 cm/s, p < 0.01), diastolic (18+/-17 vs. 44+/-14 cm/s, p < 0.01) and time-averaged (-2+/-6 vs. 26+/-9 cm/s, p < 0.01) peak velocities at rest were significantly smaller in the no-flow patent grafts than in control grafts. During hyperemia, anterograde flow became predominant, with a reduction in retrograde systolic flow signal and an increase in diastolic flow velocity and time-averaged peak velocity in the no-flow patent grafts, and no-flow situations disappeared temporarily. CONCLUSIONS: Functionally no-flow situations of IMAGs manifesting to and fro signals with systolic flow reversal and diastolic antegrade low flow velocity are temporary conditions in certain hemodynamic circumstances, and these grafts function as conduits during hyperemic states.

Adolescent↗
PubMed1998

Stimulation of leukaemic cells from adult T-cell leukaemia patients with bacterial superantigens.

Bacterial superantigens stimulate T cells in a manner that is restricted to the Vbeta of the T-cell receptor. We examined the ability of adult T-cell leukaemia (ATL) cells to respond to these superantigens. Mononuclear cells from 10 patients were cultured with staphylococcal enterotoxin A (SEA), staphylococcal enterotoxin B (SEB) or toxic shock syndrome toxin-1 (TSST-1), and their response was determined by MTT assay and 3H-thymidine incorporation assay. Cells from six patients showed a specific response to a single superantigen. In two cases the cells responded to TSST-1 and bore Vbeta2, the known target of TSST-1. In three cases the cells responded to SEA with one bearing Vbeta9, a target of SEA, and one bearing Vbeta16. In one case the cells responded to SEB. Most of the cells which proliferated in response to superantigens were determined genetically to be leukaemic. The response to TSST-1 was inhibited by anti-Vbeta2 antibody. The responding cells showed a strongly enhancement expression of interleukin-2 receptor. These findings indicate that leukaemic cells from a proportion of ATL patients have an ability to respond to T-cell receptor-dependent superantigens. This suggests that bacterial infection in such patients may contribute to the expansion of ATL cells.

Adult↗
PubMed1998

Change in bacterial community during biodegradation of aniline.

The response of river water microbial communities to chemical compounds was monitored under laboratory conditions using aniline as a model. Bacteria were collected from unpolluted and polluted sites. Bacterial abundance (plate and total direct counting) and its relation to aniline biodegradation was examined. Colony hybridization with 16S rRNA oligonucleotide probes was used to study the changes in microbial community structure during biodegradation of aniline. The changes in bacterial abundance and community structure were related to biodegradation of aniline. Burkholderia-Pseudomonas (rRNA group III), an authentic Alcaligenes group became dominant despite the initial differences in the microbial communities, suggesting that these genera are the main aniline degraders in the aquatic environment.

Alcaligenes↗
PubMed1998

Significance of Q-wave regression after anterior wall acute myocardial infarction.

AIMS: This study was conducted to clarify the significance of abnormal Q-wave regression in anterior wall acute myocardial infarction. METHODS: A total of 74 patients who presented with a first anterior wall acute myocardial infarction within 6 h of onset were divided into two groups according to the presence (group A, n = 29) or absence (group B, n = 45) of regression of abnormal Q waves. Regression of abnormal Q waves was defined as the disappearance of the Q wave and the reappearance of the r wave > or = 0.1 mV in at least one of leads I, aVL, and V1 to V6. RESULTS: Emergency coronary arteriography revealed that group A had a higher incidence of spontaneous recanalization or good collateral circulation than group B (55% vs 31%, P < 0.05). Peak creatine kinase activity tended to be lower in group A than in group B (2358 +/- 1796 vs 3092 +/- 1946 IU.L-1, P = 0.09). Group A had a greater left ventricular ejection fraction and better regional wall motion at 1 and 6 months after acute myocardial infarction than group B. The degree of improvement of left ventricular ejection fraction and regional wall motion between 1 and 6 months after acute myocardial infarction was significantly greater in group A than in group B. CONCLUSION: Patients with anterior wall acute myocardial infarction showing Q-wave regression had a trend towards a smaller amount of necrotic myocardium and a significantly larger amount of stunned myocardium.

Adult↗
PubMed1998

Gastric ulcer, atrophic gastritis, and intestinal metaplasia caused by Helicobacter pylori infection in Mongolian gerbils.

BACKGROUND: Helicobacter pylori infection is associated with gastroduodenal disease in humans. In this study we aimed to show this relationship directly in Mongolian gerbils. METHODS: The animals were challenged orally with H. pylori and killed 1, 2, 3, and 6 months after inoculation for histologic and anti-H. pylori antibody titer examination. RESULTS: The spiral bacteria were observed in the mucus and gastric pits of all infected animals. A severe infiltration of the lamina propria by polymorphonuclear and mononuclear cells was seen 1 month after H. pylori inoculation. The submucosa was infiltrated by mainly mononuclear cells with formation of lymphoid follicles. Erosion of the gastric mucosa appeared soon after inoculation, whereas gastric ulcers, gastritis cystica profunda, and atrophy with goblet cell metaplasia occurred between 3 and 6 months after inoculation. In the duodenal mucosa a mild inflammatory cell infiltration with ballooning and diminished number of duodenal glands was seen. The IgG anti-H. pylori antibody titer increased gradually after 2 months of inoculation. CONCLUSIONS: Since the gastritis, gastric ulcers, atrophic gastritis, and intestinal metaplasia that developed in Mongolian gerbils were similar to those observed in humans, this model may be useful to study the therapy of gastric ulcer and, with a longer observation period, to confirm a possible relationship between H. pylori and malignancy.

Animals↗
PubMed1998

p53 expression in gastric mucosa with Helicobacter pylori infection.

Expression of p53 was examined immunohistochemically in the Japanese monkey model with Helicobacter pylori infection of the gastric mucosa to investigate the association between H. pylori infection and gastric carcinogenesis for a period of 4 years. In the course of these observations, from 3 years after H. pylori inoculation, nuclear staining for p53 was seen in the glandular cells of the mucosa infected with H. pylori, especially in the neck region of the glands. There was a gradual increase in the number of immunopositive cases among the infected animals. Three years after inoculation, three out of six cases, and 4 years after inoculation, four out of six cases exhibited positive staining for p53. Before inoculation, and up to 2 years after inoculation, the infected group showed no immunoreaction for p53. The non-infected group likewise displayed no immunostaining for p53 through 4 years of observation. These results suggest that p53 alterations occur in the H. pylori-infected gastric mucosa and that H. pylori infection may play an important role in gastric carcinogenesis.

Animals↗
PubMed1998

Primary ductal adenocarcinoma of the lacrimal gland.

The morphological similarity of salivary and lacrimal gland tumors is known. Many clinicopathological studies and characteristics of salivary duct carcinoma, which bears histological similarities to mammary duct carcinoma, have been recently reported; however, only one case of lacrimal duct carcinoma is reported. A second case of lacrimal duct carcinoma is presented. A 67-year-old male with a painless mass in the right upper eyelid underwent total removal of the tumor mass. Microscopic examination of the tumor mass revealed ductal adenocarcinoma of the lacrimal gland, which was the equivalent of salivary duct carcinoma. The immunohistological studies of the lacrimal duct carcinoma showed similar results to those reported for salivary duct carcinoma. The recurrent tumor in the subdural spaces was removed 2 years after the initial surgery and the patient is followed as an outpatient.

Adenocarcinoma↗
PubMed1998

Non-Hodgkin's lymphoma presenting with adrenal insufficiency and hypothyroidism: an autopsy case report.

A 55-year-old male presented with an initial manifestation of primary adrenal insufficiency, hypothyroidism. Computed tomography scans showed enlarged bilateral adrenal glands and thyroid. A pathological diagnosis of diffuse large cell, B cell lymphoma was made by a needle biopsy of the adrenal gland. He was treated with combination chemotherapy and adrenal and thyroid hormone replacement. The lymphoma subsequently involved the central nervous system. He died of pneumonia 8 months after the presentation of the first symptom. The postmortem examination demonstrated a complete regression of lymphoma in the bilateral adrenal glands and thyroid. This is an extremely rare case of coexistent lymphoma of the adrenal glands and the thyroid presenting with adrenal failure and hypothyroidism.

Adrenal Insufficiency↗
PubMed1998

Osseointegration in implant-embedded mandible in rats fed calcium-deficient diet: a radiological study.

OBJECTIVE: The purpose of the present study was to investigate osseointegration using radiographs of titanium (Ti) implants into the osteoporotic mandible of rats. MATERIALS AND METHODS: Rats were divided into three groups: first group, which were fed a standard diet throughout (control group), second group which were fed a Ca-deficient diet for only 1 week before implantation (group A), and those which were fed the Ca-deficient diet before and after implantation (group B). On the 7th and 42nd days after implantation, bone changes in those rats were examined by microradiographs and autoradiographs. RESULTS: On the 7th day after implantation, calcification of newly formed bones was lower in groups A and B than in the control group, 45Ca uptake was seen in surrounding bones adjacent to the implant, as well as throughout the mandible. On the 42nd day after implantation, trabecular bone in group A showed radiopacity as seen in the control group. In the alveolar crest and peri-implanted bones in group B, thin bone formation with active 45Ca incorporation was found. CONCLUSIONS: It is suggested that irrespective of the calcium deficiency status in rats, trabecular bones around the implant are restored to a healthy state to some extent by resuming an intake of a necessary amount of dietary calcium. In continued calcium deficiency, osseointegration with the implant and alveolar bone was still observed as in the healthy rats suggesting calcium deficiency is not always a factor to regulate osseointegration of mandibular endosseous implants.

Alveolar Process↗