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Biomedical subjects

S Hamada

Publications and source records attributed to S Hamada.

At least 199 records · Page 11Linked to original sources
PubMed1994

Detection of caries-inducing microorganisms in hyposalivated rats without infection of mutans streptococci.

Rampant dental caries was induced in hyposalivated rats fed a high sucrose diet without infection of mutans streptococci, in which increased numbers of lactobacilli and S. aureus were demonstrated in the oral flora. Administration of either penicillin or piperacillin, effective against all isolates of lactobacilli, markedly inhibited the caries induction in these rats, while severe dental caries was induced in hyposalivated rats given vancomycin that is inhibitory against S. aureus. These results suggested that certain lactobacilli might induce dental caries in hyposalivated rats fed a sucrose diet. Three strains of Lactobacillus species isolated from the hyposalivated rats were made resistant to erythromycin. The caries-inducing activity of these erythromycin-resistant lactobacilli was studied in hyposalivated rats giving erythromycin in the drinking water at a concentration of 500 micrograms/ml. After a 61-day experimental period, severe dental caries was induced in hyposalivated rats infected with L. fermentum TY1R. On the other hand, low caries incidence was found in hyposalivated rats infected with either L. acidophilus TY7R or L. plantarum TY3R. These results indicate that L. fermentum may be one of causative agents of dental caries in hyposalivated rats fed a sucrose diet.

Animals↗
PubMed1994

Chemotaxis of human monocytes by synthetic peptides that mimic segments of Porphyromonas gingivalis fimbrial protein.

Porphyromonas gingivalis strain 381 fimbriae and their synthetic peptide segments were assessed for migration-stimulating activity on human peripheral blood monocytes by multiwell chemotaxis assay. P. gingivalis 381 fimbrial protein was found to markedly enhance migration of human monocytes. The observed increase in monocyte migration occurred mainly directed toward a positive stimulus (chemotaxis). Furthermore, lipopolysaccharides extracted from P. gingivalis 381 were shown to induce chemotaxis and chemokinesis. It was also revealed that the migration of monocytes was increased by specific synthetic peptide segments, FP381(61-80) and FP381(171-185), that correspond to GKTLAEVKALTTELTAENQE and DANYLTGSLTTFNGA, respectively, based on the amino acid sequence of the fimbrial subunit protein proposed by Dickinson et al., and the migration stimulation was ascribed to chemotaxis. Furthermore, within the amino acid sequences, the LTXXLTXXN sequence may play an important role in binding the organisms to monocytes and macrophages and in the induction of migration-stimulating activity.

Adhesins, Bacterial↗
PubMed1994

Hemagglutinating and chemotactic properties of synthetic peptide segments of fimbrial protein from Porphyromonas gingivalis.

Porphyromonas gingivalis 381 fimbriae, their synthetic peptide segments, and lipopolysaccharide (LPS) were examined for hemagglutinating and migration-stimulating activities. P. gingivalis 381 fimbriae clearly caused hemagglutination, and several oligopeptide segments such as FP381(61-80), FP381(171-185), and FP381(302-321), corresponding to the amino acid residue numbers based on the amino acid sequence of fimbrillin proposed by Dickinson et al. (D. P. Dickinson, M. A. Kubiniec, F. Yoshimura, and R. J. Genco, J. Bacteriol. 170:1658-1665, 1988), were also demonstrated to agglutinate erythrocytes although less effectively than the native fimbriae. Furthermore, P. gingivalis 381 LPS but not Escherichia coli O55:B5 LPS definitely exhibited hemagglutination. P. gingivalis fimbriae as well as their synthetic peptides possessing hemagglutinating activity enhanced the chemotaxically induced migration of human peripheral blood monocytes. The results of the analyses using synthetic peptide FP381(61-80), its related compounds, and an analog suggested that the amino acid sequence XLTXXLTXXNXX within fimbrial protein molecules may play an important role structurally in the attachment of the protein to host cells such as erythrocytes and monocytes.

Amino Acid Sequence↗
PubMed1994

Reduction of dental plaque deposition in humans by oolong tea extract.

The inhibitory effect of oolong tea extract (OTE) containing polymerized polyphenols on plaque deposition was examined in 35 human volunteers. Thirty-five human volunteers, aged 18-29 years, who received extensive oral prophylactic procedures were requested to refrain from all oral hygiene procedures for 4 days, and to rinse their mouth with 0.5 mg/ml OTE solution in 0.2% ethanol before and after every intake of food and before sleeping at night. No restriction regarding meals was given during the test period, except to refrain from teas or coffee. Plaque deposition was evaluated after disclosing the teeth with Erythrocin at the termination of this experiment. The study was repeated 1 week after the first trial, but only 0.2% ethanol without OTE was used for mouthrinsing in the second trial. OTE was found to significantly inhibit plaque deposition in volunteers, although mouthrinsing with OTE solution had no significant effect on the number of mutans streptococci in unstimulated whole saliva.

Adolescent↗
PubMed1994

[Clinical results of percutaneous pyeloplasty for ureteropelvic junction obstruction: 5 years follow-up].

We performed percutaneous endopyeloplasty on 20 patients between February, 1988 and July, 1993. Eighteen patients had primary and two had secondary ureteropelvic junction (UPJ) obstructions. There were 15 female and 5 male patients, whose ages ranged from 14 to 77, with an average of 43.6. The length of the follow-up after pyeloplasty ranged from 4 to 69 months with an average of 28.7 months. Among the 20 patients, there were 4 high insertion type cases, a bifid renal pelvis in one case and one case combined with a renal stone. Incisions were made with a hook-shaped cold knife and Ono's transpelvic extraureteral approach was used in most patients. Catheters were placed at the upper and the lower of renal pelvis in the patient with a bifid renal pelvis. In the case with a renal stone, pyeloplasty was successively performed after percutaneous nephrolithotomy in a single session. An endopyelotomy stent (14 Fr) was indwelled for 6 weeks in all patients except one. All patients had a low grade fever and abdominal pain for a few days after their operations, but there were no major complications. In nineteen patients (95%), the symptoms improved and their obstructive patterns disappeared or improved during follow-up. Complete ureteral stricture was found in one case at the removal of the stent and open pyeloplasty was performed. Percutaneous endopyeloplasty is a safe and useful technique, but further evaluation and/or better techniques are needed for avoiding recurrence of obstruction.

Adolescent↗
PubMed1994

[A case of inflammatory abdominal aortic aneurysm with associated inferior vena caval and bilateral ureteral obstruction].

One year ago, a 48-year-old man complained of dyspnea, and was diagnosed as mitral valve regurgitation and aortic dissection. He underwent mitral valve replacement and aortic arch grafting. He was also pointed out to have an inflammatory aortic aneurysm (IAAA) in the infrarenal abdominal aorta, but did not undergo surgery. At this admission, he had lumbago and low grade fever probably due to deterioration of the IAAA. On the preoperative radionuclide studies, inferior vena caval obstruction and bilateral ureteral obstruction or severe stenosis were demonstrated by 99mTc-MAA venography and 123I-OIH renogram, respectively. 67Ga scan showed faint abnormal accumulation at the IAAA. He underwent surgery. IAAA had a thick wall in white and hard fibrotic tissue adhered closely to duodenum, jejunum, inferior vena cava and bilateral ureters. After surgery, his renal function was improved. In this case, radionuclide studies were useful for detecting the inferior vena caval obstruction, assessing renal function and inflammatory activity.

Aneurysm, Infected↗
PubMed1993

[Detectability of diagonal branch disease with other branch lesions by 201TlCl exercised myocardial scintigraphy].

The detectability of coronary diagonal (Dx) branch disease in 24 patients (16 with myocardial infarction, 8 with angina pectoris; mean age of 56) with other branch (left anterior descending branch [LAD], left circumferential branch [LCX], or right coronary artery [RCA]) diseases was reviewed with 201TlCl exercised myocardial planar and SPECT images. In Dx branch disease with LAD #7 lesion (n = 10), Dx perfusion abnormality was detected in planar and SPECT images in 3 (30%) and 8 patients (80%), respectively. In Dx branch disease with LCX lesion (n = 7), Dx perfusion abnormality was detected in planar and SPECT images in 3 (43%) and 4 patients (57%), respectively. In Dx branch disease with RCA lesion (n = 7), Dx perfusion abnormality was detected in only 1 (14%) and 2 patients (29%), respectively. In conclusion, SPECT is a useful modality for detecting Dx branch disease, but it is sometimes hard to detect Dx branch disease with LCX and RCA lesions.

Coronary Disease↗
PubMed1993

Molecular cloning and sequencing of the fimbrilin gene of Porphyromonas gingivalis strains and characterization of recombinant proteins.

The fimA gene encoding the subunit protein of fimbriae, fimbrilin, from nine strains of Porphyromonas gingivalis was cloned using polymerase chain reaction and the nucleotide sequence was determined. Analysis of the nucleotide and the deduced amino acid sequences revealed that the fimA gene of the test strains was composed of 1044 to 1083 bp, and the molecular weight of the deduced polypeptides was calculated to be 37,527 to 38,239. All the test strains shared the same or similar sequences, but simultaneously considerable differences in the sequences were found among the strains. Western blot analysis using rabbit antiserum to P. gingivalis 381 fimbriae demonstrated that the recombinant fimbrilins of 8 out of 9 strains expressed in Escherichia coli reacted with the antiserum exhibiting a 43 to 48 kDa band. Taken together, these results indicate that four genetical clusters are noted among the fimA gene of P. gingivalis strains.

Amino Acid Sequence↗
PubMed1993

High expression rate of Tn antigen in metastatic lesions of uterine cervical cancers.

The significance of altered expression of MN blood group antigens was examined by studies on the expressions of Thomsen-Friedenreich antigen (T antigen) and Tn antigen in primary and metastatic lesions of 29 human uterine cervical cancers. These antigens were measured by the avidin-biotin-peroxidase (ABC) method with peanut agglutinin (PNA) lectin for T antigen and Vicia villosa agglutinin (VVA) lectin for Tn antigen. Proportion of cancer cells expressing Tn antigen was higher in the metastatic lesions than in the primary tumors in 10 of the 29 cases, less in the metastasis than in the primary tumor in one case, and similar in the primary and metastatic lesions in the other 18 cases. Reaction for Tn antigen was positive in 24 (82.8%) of the 29 metastases, and in 17 (58.5%) of the 29 primary lesions. Thus, the rate of Tn antigen expression was significantly higher in the metastases than in the primary lesions (P < 0.05). On the other hand, there was no significant difference between the immunoreactivities of T antigen in metastases and primary tumors. These findings support our previous suggestion that expression of Tn antigen is closely related to the metastasis to regional lymph nodes and may reflect an important role of this carbohydrate in the process of metastasis of cervical cancer.

Adenocarcinoma↗
PubMed1993

Tn antigen, a marker of potential for metastasis of uterine cervix cancer cells.

BACKGROUND: The expressions of Thomsen-Friedenreich antigen (T-Ag) and Tn antigen (Tn-Ag), precursors of MN blood group antigens, were examined in the tissues of squamous cell carcinoma of the uterine cervix from 111 patients to determine their clinicopathologic significance with regard to the biologic behaviors of cancer cells and the clinical course of the patients. METHODS: T-Ag and Tn-Ag were measured by the avidin-biotin-peroxidase (ABC) method with peanut (Arachis hypogaea) lectin (PNA) and Vicia villosa agglutinin (VVA), respectively. RESULTS: Unlike expression of T-Ag, that of Tn-Ag was correlated closely with vascular permeation of cancer cells, their parametrial spread and metastasis to the pelvic lymph nodes, and also with a low 5-year survival rate. No correlation was found between expression of Tn-Ag and other parameters, such as the clinical stage or histologic type. Furthermore, Tn-Ag expression was independent of the degree of cancer involvement in the fibromuscular stroma of the cervix, which seems to be a marker of the aggressiveness of cancer cell proliferation. CONCLUSIONS: These results indicate that Tn-Ag expression is a useful indicator of the potential for metastatic potential of cancer cells. Thus, a combination of estimations of the degree of cancer involvement in the cervical stroma and Tn-Ag expression seems the most useful for predicting the prognosis of patients with cervical cancer.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1993

[Growth rates of aortic aneurysms as a risk factor in rupture: an evaluation with CT].

There is a lack of information on the rates of growth of aortic aneurysms. In the present study, the growth rates and survival rates of thoracic and abdominal aortic aneurysms were determined. One hundred seventy-one patients with aortic aneurysm managed nonoperatively have been followed more than 6 months with sequential X-ray computed tomography. The number of aneurysms was 211 (thoracic aortic aneurysm: 82, abdominal aortic aneurysm: 129). The growth rate of thoracic and abdominal aortic aneurysms were 0.42 and 0.28 cm/year, respectively. Aneurysms at the aortic arch (n = 34) grow at a higher average rate (0.56 cm/year) than aneurysms arising at other levels (p < 0.05). The survival rates showed the tendency that the higher the growth rate, the worse the survival rate. The survival rate of aortic arch aneurysm was significantly decreased when the growth rate was higher than the mean value. It is recommended that thoracic aortic aneurysms, especially aortic arch aneurysms, be followed frequently with computed tomographic examination of size.

Adult↗
PubMed1993

[Detection of myocardial fatty components with ultrafast CT].

Intramyocardial fatty components are sometimes depicted by CT of the thorax. However, no studies have investigated the distribution, frequency and cause of these components by using statistical analysis. Three hundred forty-five patients with various cardiac diseases were examined with an ultrafast CT scanner, and intramyocardial fatty components were detected in 15 (4.3%) of them. The frequency of intramyocardial fatty components in each disease was as follows: 6% in ischemic heart disease, 7% in Kawasaki disease, 11% in hypertrophic cardiomyopathy (HCM), 18% in dilated cardiomyopathy (DCM) and 33% in arrhythmogenic right ventricular dysplasia (ARVD). Except for patients with HCM, the segments of the ventricles, where the fatty components were detected, agreed well with the segments with asynergy in left ventriculography and/or the segments with perfusion defect in T1 myocardial scintigraphy. Thus, ischemic fatty degeneration was considered to be a main factor in the production of intramyocardial fatty components in these diseases. The focus of arrhythmia was sometimes detected in the segments with intramyocardial fatty components in DCM and ARVD cases. It is suspected that intramyocardial fatty components sometimes produce arrhythmia in these diseases.

Adipose Tissue↗
PubMed1993

[Detection of myocardial damage in patients with dilated cardiomyopathy using ultrafast CT].

The myocardial characteristics of DCM patients were investigated by ultrafast CT (UFCT), left ventriculography (LVG) and T1 myocardial scintigraphy (SCINTI). Late enhancement, focal wall thinning and intramyocardial fatty components were detected as focal abnormal findings by UFCT. The regions of asynergy detected by LVG and perfusion defect detected by SCINTI were well correlated with those of focal abnormal findings detected by UFCT. There were significant differences between patients with and without focal abnormal findings, in ejection fraction and end-diastolic pressure of left ventricle and the incidence of ventricular arrhythmia. It is possible that these focal abnormal findings represented focal ischemic myocardial damage in DCM patients. DCM patients were divided into two different functional groups by UFCT findings.

Adolescent↗
PubMed1993

Synaptic loss following removal of serotoninergic fibers in newly hatched and adult chickens.

Neurotransmitters such as serotonin (5HT) may have nontransmitter, trophic-like functions in the developing and adult nervous system. In order to examine this possibility in the avian spinal cord, we have quantified synapse numbers on spinal neurons following treatment with drugs that result in the destruction of 5HT positive axons. Either p-chlorophenylalanine or reserpine was injected into newly hatched or adult chickens. Following treatment for 7 days the density of nonserotoninergic synapses was considerably decreased in the targets of 5HT fibers. By contrast, neither change was observed in the dendritic structures of spinal motoneurons or in the distribution of substance P and enkephalin positive fibers. These data suggest that 5HT may play an important role in the normal increase and maintenance of synapses in developing and adult animals. A lesion of 5HT neurons may not only alter neurochemistry but also alter the general synaptic structures of the brain. While 5HT containing fibers were depleted in a dose-dependent fashion we cannot rule out the possibility that other neurotransmitter systems were depleted at higher dose of PCPA and reserpine.

Animals↗
PubMed1993

Conformational changes of alpha-lactalbumin and its fragment, Phe31-Ile59, induced by sodium dodecyl sulfate.

Conformational changes of bovine alpha-lactalbumin in sodium dodecyl sulfate (SDS) solution were studied with the circular dichroism (CD) method using a dilute phosphate buffer of pH 7.0 and ionic strength 0.014. The proportions of alpha-helix and beta-structure in alpha-lactalbumin were 34% and 12%, respectively, in the absence of SDS. In the SDS solution, the helicity increased to 44%, while the beta-structure disappeared. In order to verify the structural change from beta-structure to alpha-helix, the moiety, assuming the beta-structure in the alpha-lactalbumin, was isolated by a chymotryptic digestion. The structure of this alpha-lactalbumin fragment, Phe31-Ile59, was almost disordered. However, the fragment adopted a considerable amount of alpha-helical structure in the SDS solution. On the other hand, the tertiary structure of alpha-lactalbumin, detected by changes of CD in the near-ultraviolet region, began to be disrupted before the secondary structural change in the surfactant solution. Dodecyl sulfate ions of 80 mol were cooperatively bound to alpha-lactalbumin. Although the removal of the bound dodecyl sulfate ions was tried by the dialysis against the phosphate buffer for 5 days, 4 mol dodecyl sulfates remained per mole of the protein. The remaining amount agreed with the number of stoichiometric binding site, determined by the Scatchard plot, indicating that the stoichiometric binding was so tight.

Circular Dichroism↗