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Biomedical subjects

I Kobayashi

Publications and source records attributed to I Kobayashi.

At least 163 records · Page 9Linked to original sources
PubMed1999

Prediction of optimal atrioventricular delay in patients with implanted DDD pacemakers.

In patients with an implanted DDD pacemaker (PM), the atrial contribution may be interrupted by too short an atrioventricular (AV) delay, and filling time may be shortened by too long an AV delay. The AV delay at which the end of the A wave on transmitral flow coincides with complete closure of the mitral valve may be optimal. The subjects were 15 patients [70.3+/-12.3 (SD) years old] with an implanted DDD PM. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter. Transmitral flow was recorded by pulsed Doppler echocardiography. AV delay was prolonged stepwise by 25 msc. When the AV delay was set at 155+/-26 ms, the end of the A wave coincided with complete closure of the mitral valve. When the AV delay was prolonged 25, 50, 75, and 100 ms from this AV delay, the interval between the end of the A wave and complete closure of mitral the valve was prolonged 16+/-5, 39+/-6, 65+/-4 and 88+/-5 ms, respectively (r = 0.97, P<0.0001) and diastolic mitral regurgitation was observed during this period. Thus, the optimal AV delay may be predicted as follows: the slightly prolonged AV delay minus the interval between the end of the A wave and complete closure of the mitral valve. When the AV delay was set at 215 ms, there was a significant positive correlation between the predicted optimal AV delay (166+/-23 ms) and the optimal AV delay (CO: 161+/-26 msec, r = 0.93, P<0.0001, PCWP: 161+/-28 msec, r = 0.95, P<0.0001). In conclusion, optimal AV delay can be predicted by this simple formula: slightly prolonged AV delay minus the interval between end of A wave and complete closure of mitral valve at the AV delay setting.

Aged↗
PubMed1999

Induction of cytosolic phospholipase A2 and prostaglandin H2 synthase-2 by lipopolysaccharide in human polymorphonuclear leukocytes.

Polymorphonuclear leukocytes (PMNs) produce arachidonic acid (AA) metabolites including thromboxane A2 (TXA2). These cells are the first line of defense against bacterial invasion, which often causes endotoxin shock. TXA2 which plays an important role in the pathogenesis of endotoxin shock is synthesized by three consecutive enzyme activation, cytosolic phospholipase A2 (cPLA2), prostaglandin H2 synthase (PHS type 1 and type 2) and TXA2 synthase. Among them, cPLA2- and PHS-2 activity is known to be transcriptionally and/or posttranscriptionally up-regulated by various bioactive substances including lipopolysaccharide (LPS), a bacterial endotoxin, in many cell types. We investigated the action of LPS on TXA2 synthesis in human PMNs. A23187-stimulated production of thromboxane B2 (TXB2, a stable metabolite of TXA2), assayed by specific radioimmunoassay (RIA), was significantly increased from 566.7+/-44.1 pg/10(6) cells to 966.7+/-44.1 pg/10(6) cells (p<0.05) after 6 h-exposure to LPS at the concentration of 100 ng/ml. Messenger RNA for PHS-2, PHS-1, TXA2 synthase and cPLA2, which was assessed by reverse transcription-polymerase chain reaction (RT-PCR), was expressed in PMNs without LPS stimulation. Although PHS-2 was putatively an inducible enzyme, abundance of mRNA for PHS-2 in PMNs without LPS stimulation was detectable. Messenger RNA abundance for PHS-2 and cPLA2, but not for PHS-1 and TXA2 synthase, was enhanced by LPS-treatment, indicating that the increased production of TXB2 was attributable to the up-regulation of cPLA2 and PHS-2. We conclude that (1) PHS-2 plays a more important role than PHS-1 in the production of TXA2 in human PMNs and (2) TXA2 synthesis in human PMNs is transcriptionally up-regulated by new induction of cPLA2 as well as PHS-2, when the cells encounter endotoxin producing bacteria.

Aspirin↗
PubMed1999

Immunohistochemical and ultrastructural study of a papillary cystadenocarcinoma arising from the sublingual gland.

Immunohistochemical and ultrastructural findings in a rare case of papillary cystadenocarcinoma arising from the left sublingual gland of a 55-year-old Japanese man are reported. Histologically, the tumor tissue was found to be composed of various-sized cystic cavities in which papillary epithelial projections with thin fibrovascular cores were observed. The papillary projections consisted of a single layer to several layers of high columnar epithelial cells. Invasion to the surrounding fibrous tissue and into the lymphatics was observed, thus suggesting an aggressive potential in the present case. The possibility of the involvement of myoepithelial cells could be excluded based on the immunohistochemical and ultrastructural findings. The immunohistochemical and ultrastructural findings also suggested that this type of salivary gland tumor, at least the present case, may arise from striated or excretory ducts. There was positive immunostaining for tumor markers CA19-9 and CA125. However, the biological role of these carbohydrate antigens in salivary gland tumors is unclear at present. Further investigations are, therefore, called for to solve this issue.

Biomarkers, Tumor↗
PubMed1999

[Evaluation of mycobacteria growth indicator tube (MGIT), an automated culture system for detection of mycobacteria from clinical specimens].

We compared the Mycobacteria Growth Indicator Tube 960 (MGIT 960) and Ogawa medium (OM) for the detection of mycobacteria (acid fast bacteria: AFB) using 882 sputum specimens. Overall, 120 strains of AFB were isolated by the MGIT 960 system and 99 strains of AFB were isolated by using OM. As far as Mycobacterium tuberculosis is concerned, 88 and 71 isolates were achieved by the MGIT 960 and OM respectively. A total of 28 isolates (18 isolates of M. tuberculosis and 10 isolates of nontuberculous mycobacteria: NTM) were detected by the MGIT 960 only whereas only 2 isolates (1 M. tuberculosis and 1 NTM) were detected by OM only. Of these sputum specimens, 72 were smear positive for AFB. The rates of smear negative but culture positive specimens were 8.0% (65 out of 809) for the MGIT 960 system and 6.2% (50 out of 809) for OM. The contamination rate for MGIT 960 was only 1.2%. The average time required for detection of M. tuberculosis was 14.1 days by the MGIT 960 system and 24.6 days by OM. For the NTM, the average detection time were 8.3 days for the MGIT 960 system and 22.8 days for OM. These results indicate that the MGIT 960 system allows detection of mycobacteria significantly faster than OM.

Automation↗
PubMed1999

[Effect of antibiotics and antibody on phagocytic bactericidal activity of polymorphonuclear neutrophils of Bordetella pertussis].

The phagocytic bactericidal activity of the polymononucler neutrophils (PMNs) that were collected from healthy volunteer with and without antibody against Bordetella pertussis was investigated. Furthermore, these activity against B. pertussis under observing penicillins or macrolides antibiotics was investigated. Although no efficacy to B. pertussis strain by the PMNs in serum without antibody, but the viable cells of B. pertussis decreased to 1/1,000 1 hr after incubation and was not detected after 4 hrs. In particular, the viable cells of B. pertussis by the PMNs in serum with antibody was markedly reduced when azithromycin was present. These results suggests that the synergistic action of macrolide antibiotics and antibody-mediated phagocytic bactericidal activity on B. pertussis may have clinical relevance.

Anti-Bacterial Agents↗
PubMed1999

[Development of an enzyme-linked immunosorbent assay (ELISA) for detection of IgM and IgG antibodies to lipopolysaccharide of Escherichia coli O157].

We developed the enzyme-linked immunosorbent assay (ELISA) for detection of serum IgM and IgG antibodies to lipopolysaccharide (LPS) of Escherichia coli O157:H7 (VT1+, VT2+) isolated from a clinical sample. We tested the patient's sample with hemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC). And we evaluated the value of sample OD to cut off control OD as the Index. The CVs obtained in precision studies were below 10% for intra- and inter-assay, respectively. The cut off index value of infants and children (0 to 5 years) was 0.60 for IgM and 0.95 for IgG. Moreover we investigated the specificity to E. coli O157 from other E. coli serotypes in this method. From these results, O27 serotype was crossreacted in this assay, but other serotypes were not reacted. In the patients with HUS and HC, some cases were already positive for IgM at 3 days, but for IgG 8 days were needed for it to become positive. We concluded that this ELISA for IgM and IgG for E. coli O157 LPS have a useful performance, and might be the useful tool for rapid diagnosis for E. coli O157 infection.

Antibodies, Bacterial↗
PubMed1999

C-Reactive protein in dilated cardiomyopathy.

The prognosis for patients with idiopathic dilated cardiomyopathy (DCM) is poor, although clinical features are variable. Prediction of outcome has been difficult in individual patients based on laboratory data. In some patients with DCM, myocardial damage secondary to viral or immune-mediated myocardial inflammation may persist. To objectively assess inflammation, we measured plasma concentrations of C-reactive protein (CRP) in 188 patients with idiopathic DCM over 5-8 years. All had dyspnea and fatigue at rest; all patients had a left ventricular ejection fraction less than 40% by echocardiography or by contrast or radionuclide ventriculography. We divided these patients into two groups: patients dying within 5 years following admission (n = 49) and the remainder surviving for at least 5 years (n = 139). CRP concentrations in the patients dying early were significantly higher than in the long-term survivors (1. 05 +/- 1.37 vs. 0.49 +/- 1.04 mg/dl, p < 0.05). Sixty-two percent of the patients with CRP>1.0 died within 5 years. In addition to other laboratory tests including electrocardiography and echocardiography, routine CRP measurements proved to be valuable for identifying high-risk patients who require special treatment strategies.

Adult↗
PubMed1999

An interleukin-6-producing cardiac myxoma associated with mediastinal lymphadenopathy.

We report our experience with a patient whose mediastinal lymphadenopathy resolved after resection of a cardiac myxoma that secreted interleukin-6 (IL-6). The patient was a 68-year-old female who complained of nocturnal chest discomfort related to congestive heart failure. An echocardiogram demonstrated a large left atrial mass. A computed tomogram showed not only the left atrial mass but multiple enlarged mediastinal lymph nodes. The serum IL-6 level was markedly elevated at 13.7 pg/ml. After resection of the cardiac myxoma, serum IL-6 returned to the normal range. A repeat computed tomogram showed no mediastinal lymphadenopathy. We believe that overproduction of IL-6 by the cardiac myxoma was the cause of the mediastinal lymphadenopathy.

Aged↗
PubMed1999

Genotypic evolution in a quinolone-resistant Neisseria gonorrhoeae isolate from a patient with clinical failure of levofloxacin treatment.

Recently, a reduction in the antimicrobial susceptibility of clinical isolates of Neisseria gonorrhoeae to newer fluoroquinolones including levofloxacin in vitro has been recognized in Japan. We examined the quinolone resistance mechanisms in N. gonorrhoeae isolates from a patient with clinical failure of levofloxacin treatment. Man with gonococcal urethritis was treated with oral 100 mg levofloxacin 3 times daily for 7 days. However, clinical failure of the treatment was observed. The minimum inhibitory concentration of levofloxacin for the posttreatment isolate (4.0 microg/ml) was 4-fold higher than that for the pretreatment isolate (1.0 microg/ml). To analyze quinolone resistance mechanisms in the set of isolates, we performed DNA sequencing of the quinolone resistance-determining regions within the gyrA and parC genes. Moreover, we assayed the intracellular levofloxacin and norfloxacin accumulation level in these isolates. The pretreatment isolate contained three substitutions compared to susceptible wild-type isolate, including serine to phenylalanine at position 91 and aspartic acid to asparagine at position 95 in the GyrA protein, and serine to proline at position 88 in the ParC protein. The posttreatment isolate had four substitutions, including the same three substitutions and an additional glutamic acid to glutamine substitution at position 91 in ParC. There was no significant difference in the level of accumulation of levofloxacin and norfloxacin between the pretreatment and posttreatment isolates. Our results indicate that levofloxacin selects a mutant having an additional alteration within the gene cording for the ParC protein during treatment, which may have enhanced quinolone resistance in the organism.

Adult↗
PubMed1999

Angiotensinogen gene polymorphism near transcription start site and blood pressure: role of a T-to-C transition at intron I.

Molecular variants of the angiotensinogen gene, a key component of the renin-angiotensin system, are considered genetic risk factors for primary hypertension. A relation between the angiotensinogen gene locus and hypertension has been found in whites, Japanese, and African Caribbeans but not in Chinese. The lack of a consistent association between M235T polymorphism at exon 2 and hypertension has suggested that another site in linkage disequilibrium with M235T is the causal mutation. We studied the relations among plasma angiotensinogen concentrations, blood pressure, related clinical variables, and mutations of the 5' upstream core promoter region of the human angiotensinogen gene in 274 subjects recruited from our outpatient clinic. We confirmed that plasma angiotensinogen concentration was significantly correlated with A-20C mutation and percent body fat and found that systolic and diastolic blood pressures were significantly correlated with G-6A and T+68C mutations. These results suggest that mutations near the transcription start site may be associated with increased blood pressure.

Angiotensinogen↗
PubMed1999

Sudden death with malignant hemangioendothelioma originating in the pericardium--a case report.

The authors report a rare case of a malignant hemangioendothelioma (MH) originating in the pericardium. In this case, a metastatic skin lesion was found first, and subsequently the existence of a primary cardiac lesion was confirmed. Generally, primary cardiac tumors grow slowly, and the prognosis of MH is relatively good. In this case, however, the patient died suddenly during the creation of a pericardial window for drainage. An autopsy showed that the MH originated from a pericardial lesion in the right atrium.

Death, Sudden↗
PubMed1999

Behaviour of urinary dipeptidase in patients with chronic renal failure.

Renal dipeptidase (EC 3.4.13.19) activity in serum and urine from healthy volunteers (n = 20), patients with diabetes (n = 18) and patients with chronic renal failure (n = 5) was measured using glycyl-D-alanine as substrate. The assay was highly specific for the enzyme and was not affected by the various aminopeptidases present in serum and urine. No difference in serum renal dipeptidase activity was observed between the groups. The enzyme activity (U/L) in urine was higher than that in serum, irrespective of the group, suggesting the urine concentration was not affected by the serum concentration. The mean renal dipeptidase activities in urine were 2.56, 2.46 and 0.78 U/mol creatinine for healthy subjects, patients with diabetes and patients with chronic renal failure, respectively. The renal dipeptidase activity was significantly lower in the chronic renal failure group. The urinary excretion of dipeptidase (U/mmol creatinine) showed significant inverse correlations with that of beta 2-microglobulin, albumin and alpha 1-microglobulin, and with serum concentrations of creatinine, beta 2-microglobulin and alpha 1-microglobulin. We suggest that urine dipeptidase may be a useful marker of renal diseases.

Adult↗
PubMed1999

Age-dependent changes in the distribution of BrdU- and TUNEL-positive cells in the murine gingival tissue.

BACKGROUND: Age-dependent morphological and cell kinetic changes of the gingival tissue seem to be related to the occurrence of periodontal disease. The purpose of this study was to investigate the age-dependent changes in the distribution of BrdU- and TUNEL-positive cells in murine gingival tissue. METHODS: Gingival tissue of the lower first molar region of 2-, 3-, 5-, 7-, 10-, 15-, 20-, 30-, 40-, 50-, 60-, 70- and 80-week-old mice was used in this study. BrdU- and TUNEL-positive cells were evaluated at the following 4 sites: 1) gingival epithelium (GE); 2) junctional epithelium (JE); 3) submucosal connective tissue of the gingival epithelium (GECT); and 4) submucosal connective tissue of the junctional epithelium (JECT). RESULTS: No significant differences in the mean number of BrdU-positive cells at each site were demonstrated among the various age groups. No significant change in the mean number of TUNEL-positive cells was demonstrated in either the GE or JE groups among the various age groups. Meanwhile, a significant increase in the TUNEL-positive cells was observed in the GECT of mice 40 weeks or older, and in the JECT of mice 20 weeks or older. CONCLUSIONS: These results indicate that no age-dependent change in the cell proliferation or cell death occurred in the gingival and junctional epithelial layers as well as in the cell proliferation in the submucosal connective tissue. Meanwhile, a significant decrease in the cellular component of the submucosal connective tissue of both gingival and junctional epithelial layers caused by apoptosis occurred with aging. The decreased cellular component in the submucosal connective tissue thus seems to be related to either gingival recession or to the apical migration of the JE with aging. These morphological changes with aging possibly occur in humans and may be related to the susceptibility to periodontal disease in aged individuals.

Aging↗
PubMed1999

Skin toxicity of propranolol in guinea pigs.

The skin toxicities of propranolol were studied in guinea pigs. In the primary and cumulative skin irritation studies, the skin reactions and the histopathological changes were observed in all animals treated with propranolol, and those tended to increase with the increase of propranolol dosage. The skin reactions increased with the application times of propranolol up to 7 days in the cumulative skin irritation study. In the skin sensitization, the phototoxicity and the skin photosensitization studies, no skin reactions were observed in any animals used in the studies. These results indicate that propranolol caused skin irritation, but was negative for skin sensitization, phototoxicity and skin photosensitization in guinea pigs.

Adrenergic beta-Antagonists↗
PubMed1999

[Efficacy and safety of endoscopic papillary balloon dilation for removal of common bile duct stones in the elderly].

From May 1996 through August 1998, endoscopic papillary balloon dilation (EPBD) was performed to remove common bile duct stones in 17 elderly patients, aged 75 to 87 (average 81.9), including 7 with juxtapapillary diverticulum. The balloon-tipped biliary catheter for EPBD was inflated at a pressure of 10 atm, for 2 minutes, and the maximum diameter of the inflated balloon reached 8 or 10 mm. After one or two ERCP sessions using EPBD alone, the bile duct stones were removed in 16 (94.1%) of 17 patients, and endoscopic mechanical lithotripsy was required in 6 (35.3%) patients. Another patient required additional sphincterotomy for removal of the stone. Massive bleeding or intestinal perforation, which can be major complications of EPBD, did not occur, and while the minor complication of transient abdominal pain was observed in 3 patients but there was no case of pancreatitis. The clearance rates of stones and complication rates in our EPBD procedure were similar to other reports and to those of our data in younger patients, aged under 75. EPBD was a safe and effective technique for the extraction of the common bile duct stones in elderly patients.

Aged↗
PubMed1999

[Congestive heart failure due to a combination of atrial fibrillation and tricuspid regurgitation: clinical course and echocardiographical analysis].

The combination of atrial fibrillation (Af) and tricuspid regurgitation (TR) may induce the congestive heart failure (HF) due to insufficient output. However, these associations have not been elucidated. We examined the clinical course with echocardiographic data in 119 patients with Af and/or TR and/or HF. Their mean age was 65 +/- 14 years. The patients were classified into 6 groups as follows: Group I contained patients with Af, TR and HF(n = 13); Group II contained patients with Af and TR, without HF(n = 59); Group III contained patients with TR and HF, without Af(n = 15); Group IV contained patients with TR and without AF and HF(n = 15); Group V contained patients with Af and HF, without TR(n = 24); Group VI contained patients with Af and without TR and HF(n = 13). The fractional shortening and ejection fraction in Group I and II were significantly (p < 0.05) decreased compared to Group IV. Moreover, the fractional shortening in Group V was significantly (p < 0.05) lower than in Group IV. Among 72 cases in Group I and II, 24 cases were followed by echocardiography for 2 to 5 years. Eight cases of HF exhibited a no HF state and 1 demonstrated had the HF state. All 9 cases (38%) showed a decreased heart rate and no alternation of TR. Four of the 24 patients (17%) had developed worsened TR and a lowered ejection fraction but none developed them became HF. Therefore, tachycardia may be an accelerative factor for HF due to the combination of Af and TR, not due to the grade of TR.

Aged↗
PubMed1999

[Survey of the sensitivities of clinical isolates to antibacterial agents (annual report)].

Research groups were formed in 21 institutions nationwide to investigate carbapenem resistance. The activities of various antibacterial agents, principally carbapenems, were tested against clinical isolates collected from these institutions. The broth microdilution method was used to determine the minimum inhibitory concentrations (MIC) of 17 antibacterial agents for 1,241 strains of 11 bacterial species isolated at all institutions between October and December 1996. The results were as follows: Carbapenems exhibited strong antibacterial activities against MSSA and Streptococcus pneumoniae and showed low activities against MRSA. Their activities against Enterococcus faecalis were comparable to that of ampicillin and piperacillin. The carbapenems showed high activities against Haemophilis influenzae, Escherichia coli, Klebsiella pneumoniae. Enterobacter cloacae. Serratia marcescens and Bacteroides fragilis group. Their activities were greater than that exhibited by other beta-lactam antibacterial agents, but some resistant strains of Serratia marcescens were detected. The antibacterial activity of carbapenems against Pseudomonas aeruginosa was comparable to that of CAZ, and there were some resistant strains.

Carbapenems↗