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Biomedical subjects

K Mikasa

Publications and source records attributed to K Mikasa.

At least 19 recordsLinked to original sources
PubMed2001

[Acute exacerbations due to Streptococcus pneumoniae in chronic lower respiratory tract infections during long-term macrolide therapy].

In Japan, long-term 14-membered macrolide administration is chosen as a first line therapy against chronic lower respiratory tract infections (CLRTIs) such as diffuse panbronchiolitis, bronchiectasis and chronic bronchitis. However, sometimes acute exacerbations occur in these cases, even if therapy is effective. We investigated 18 episodes of CLRTIs exacerbations that were caused by Streptococcus pneumoniae during long-term macrolides therapy from 1991 to 1999 to clarify the clinical features and prevalence of antimicrobial resistance in S. pneumoniae. Exacerbations did not occur only in winter season, but also in other seasons. Among 18 episodes of exacerbation, only 7 episodes (39%) revealed infiltration in chest roentogenogram and few episodes revealed marked elevations of inflammation markers in laboratory data. Intermediate resistance or resistance rates of S. pneumoniae isolated from sputum or transtracheal aspiration were 100% to erythromycin, 67% to clindamycin or minocycline, 11% to ampicillin, and 0% to cephazoline or imipenem. Coresistance to erythromycin, clindamycin and minocycline was seen in a half of the episodes. Resistance was not correlated with the duration of macrolides administration. All episodes were mainly treated with beta-lactam agents or fluoroquinolones and cured successfully. These findings suggest that acute exacerbations in CLRTIs caused by S. pneumoniae during long-term macrolides therapy do not reveal severe clinical aspects and can be treated successfully at present, but attention should be paid to the trend of antibiotic susceptibility in S. pneumoniae.

Adolescent↗
PubMed2001

[Pathogenetic study on bronchopulmonary infections in 1,416 patients by transtracheal aspiration method].

We have performed transtracheal aspiration (TTA) in 1,416 patients, who were suspected to have bronchopulmonary infection, in order to collect non-contaminated specimens directly from the lower airway. The overall isolation rates in 1,416 TTA were 68.7% for any microorganisms. Aerobes had a high incidence but many kinds of microorganisms were associated with bronchopulmonary infections. Haemophilus influenzae was the major pathogen in patients with acute bronchitis. Streptococcus pneumoniae was the most important pathogen and mycoplasma was often isolated in patients with community-acquired pneumonia. Major pathogens of nosocomial pneumonia consisted of alpha-streptococcus spp., anaerobes and Pseudomonas aeruginosa. Anaerobes were isolated from transtracheal aspirates in 20 of 33 episodes of lung abscesses. H. influenzae and P. aeruginosa were the main persistent pathogens and H. influenzae, S. pneumoniae and anaerobes were important exacerbated pathogens in patients with chronic lower respiratory tract infection. S. pneumoniae was isolated more from TTA than expectorated sputa. Oropharyngeal flora bacteria were easily isolated in the culture of expectorated sputa. We assessed the final diagnosis or causative factor in 443 patients whom no microorganism was isolated from transtracheal aspirates. The final diagnosis was infectious diseases in 52 patients (11.7%) and non-infectious diseases in 80 patients (18.1%), respectively. The causative factor was unsuited TTA sample in 81 patients (18.3%), preceding antimicrobial chemotherapy in 95 patients (21.4%) and unknown in 135 patients (30.5%), respectively. The pathogenesis of bronchopulmonary infections is complex and various microorganisms are associated with pathogens of bronchopulmonary infections. Therefore, we should accurately diagnose the pathogens in patients with bronchopulmonary infections. TTA is one of the useful methods that we can accurately detect the respiratory pathogens.

Adolescent↗
PubMed2001

Anti-cachectic effect of clarithromycin for patients with unresectable non-small cell lung cancer.

We have previously reported that long-term treatment with clarithromycin (CAM) increased the median survival of patients with non-small cell lung cancer, and improved various clinical parameters in these patients. In the present study, CAM was administered to 33 patients with unresectable primary non-small cell lung cancer, who had received chemotherapy, radiotherapy or both (basic cancer therapy). Patients with clinical backgrounds matched to the CAM group, who did not receive CAM treatment, were included into this study as a control group (non-CAM group). CAM treatment was initiated 4 weeks after the basic cancer therapy. The non-CAM group did not receive a placebo. Before and after the 3-month treatment with CAM, body weight, serum levels of interleukin-6 (IL-6, a cytokine which, together with TNF-alpha, plays a crucial role in the development of cancer cachexia), total protein, albumin, cholinesterase and hemoglobin were measured for the evaluation of the patients' clinical status. There were no statistically significant differences in serum levels of IL-6 between the CAM group before the treatment and the non-CAM group. After 3 months of CAM treatment, serum levels of IL-6 significantly decreased. In contrast, body weight, cholinesterase, and hemoglobin increased to a significant extent. Among these four parameters, however, the decrease in serum IL-6 levels was only statistically correlated with the increase in body weight, but not with that in other parameters. Furthermore, CAM-treated patients whose serum IL-6 levels were decreased after 3 months of treatment survived longer: there was a statistically significant correlation between the decrease in serum IL-6 and survival time. In contrast, in the non-CAM group, these parameters did not change significantly during the study. These results suggest that CAM may reduce the progression of cancer-associated cachexia.

Aged↗
PubMed2000

Pathogenic mechanism of mouse brain damage caused by oral infection with Shiga toxin-producing Escherichia coli O157:H7.

In a previous study, we showed that infection with Shiga toxin (Stx)-producing Escherichia coli O157:H7 (strain Sm(r)N-9) caused neurologic symptoms in malnourished mice with positive immunoreactions of Stx2 in brain tissues. The present study explores the mechanism of how Stx injures the vascular endothelium to enter the central nervous system in mice. Oral infection with strain Sm(r)N-9 elicited a tumor necrosis factor alpha (TNF-alpha) response in the blood as early as 2 days after infection, while Stx was first detected at 3 days postinfection. In the brain, TNF-alpha was detected at day 3, and its quantity was increased over the next 3 days. Frozen sections of the brains from moribound mice contained high numbers of apoptotic cells. Glycolipids recognized by an anti-Gb3 monoclonal antibody were extracted from the brain, and purified Stx2 was able to bind to the glycolipids. In human umbilical vascular endothelial cells (HUVEC) cultured with fluorescein-labeled Stx2 (100 ng/ml), TNF-alpha (20 U/ml) significantly facilitated the intracellular compartmentalization of fluorescence during 24 h of incubation, suggesting the enhanced intracellular processing of Stx2. Consequently, higher levels of apoptosis in HUVEC were found at 48 h. Short-term exposure of HUVEC to Stx2 abrogated their apoptotic response to subsequent incubation with TNF-alpha alone or TNF-alpha and Stx2. In contrast, primary exposure of HUVEC to TNF-alpha followed by exposure to Stx2 alone or TNF-alpha and Stx2 induced apoptosis at the same level as obtained after 48-h incubation with these two agents. These results suggest that the rapid production of circulating TNF-alpha after infection induces a state of competence in vascular endothelial cells to undergo apoptosis, which would be finally achieved by subsequent elevation of Stx in the blood. In this synergistic action, target cells must be first exposed to TNF-alpha. Such cell injury may be a prerequisite to brain damage after infection with Stx-producing E. coli O157:H7.

Animals↗
PubMed1999

[Enterococcus gallinarum septicemia in a patient with acute myeloid leukemia].

A 62-year-old male was admitted with complaints of fever and body weight loss. The patient was diagnosed as acute myeloid leukemia (M1) and chemotherapy was started. About 80 days after admission, the patient developed diarrhea with high fever. And E. gallinarum was isolated from the blood culture. We carried out PCR using primers for vanA, vanB and vanC in our E. gallinarum, and showed the existence of the vanC1. This organism should be considered as one of the possible pathogenes in the infectious complications of the immuno-compromized patient.

Bacteremia↗
PubMed1999

[Clinical evaluation of anaerobic infections in patients with bronchopulmonary infections diagnosed by transtracheal aspiration].

We evaluated the clinical and bacteriologic features in the patients with bronchopulmonary infections isolated anaerobes from transtracheal aspirates between April 1990 and March 1998. Some anaerobe was isolated in 42 (10.9%) in 387 patients whom we performed transtracheal aspiration (TTA), in 42 (15.7%) of 268 in whom some organism was isolated from TTA, or in 42 (16.3%) of 257 patients in whom some bacterium excluding acid-fast bacteria, fungi or mycoplasma from TTA. The isolation rate of anaerobic bacteria was 93.3% in the patients with lung abscess, 22.7% in the patients with nosocomial pneumonia, 19.4% in the patients with community-acquired pneumonia, 26.7% in the patients with acute exacerbation of chronic lower respiratory tract infection (CLRTI), 1.6% in the patients with persistent infection of CLRTI, and 3.0% in the patients with acute bronchitis, respectively. The major anaerobes, isolated from TTA, were Peptostreptococcus micros and Prevotella melaninogenica. The aerobic bacteria were isolated with anaerobic bacteria in 32 of 42 patients at the same time. The quantitive grade of colonial growth of anaerobes was equal to or more than aerobes in the patients with lung abscess and pneumonia. We mostly administrated 3rd generation cephems or carbapenems with or without clindamycin for the treatment of anaerobic infections. Forty-one of 42 patients were cured only by the therapy of antimicrobial agents, but pneumonia patient with lung cancer died in spite of adequate antimicrobial therapy. These results suggest that the anaerobic infections are important in the bronchopulmonary infections.

Bacteria, Anaerobic↗
PubMed1999

[A case of common variable immunodeficiency that responded to long-term erythromycin chemotherapy].

A 32-year-old woman with common variable immunodeficiency (CVID) accompanied by sinopulmonary infection was evaluated for purulent sputum, cough, and nasal obstruction that did not respond to regular intravenous immunoglobin (IVIG) infusion. Chest X-ray films revealed bronchiectasis affecting both lung bases, and a bacteriological examination of sputum was positive for Pseudomonas aeruginosa. Long-term chemotherapy with erythromycin (EM) was started, and the patient's respiratory symptoms gradually subsided. Sinopulmonary infection is the dominant clinical complication in patients with CVID. This case suggested that long-term EM chemotherapy is useful for the treatment of IVIG-refractory sinopulmonary infection associated with CVID.

Adult↗
PubMed1998

[Two cases of Achromobacter xylosoxidans sepsis].

Achromobacter xylosoxidans is a gram-negative bacterium whose natural habitat has not been clearly defined. It has been isolated from ear discharge and the large intestine of humans and from various hospital or environmental water sources. Infection with A. xylosoxidans in humans has been documented, and resulting illnesses include meningitis, pneumonia, cholecystitis, peritonitis and urinary tract infection. Bacteremia due to A. xylosoxidans is rare, and little information on treatment is available. Two cases of bacteremia due to A. xylosoxidans in patients with hemapoietic malignancies are reported herein. Case 1 involved a 70-yr. male whose clinical diagnosis was IgA lambda-type plasmacytoma. Case 2 involved 72-yr. male whose clinical diagnosis was acute lymphatic leukemia (L2). Both patients had been catheterized. Neutropenia was noted and the white blood cell counts were 20/microliter in case 1 and 35/microliter in case 2 when A. xylosoxidans was isolated from the blood culture. We suggest that bacteremia due to A. xylosoxidans may have been related to the presence of the catheter and neutropenia.

Aged↗
PubMed1998

[A clinical study of respiratory infection isolating non-pathogenic Neisseria by transtracheal aspiration].

Neisseria species other than N. meningitidis and N. gonorrhoeae are generally regarded as commensal bacterial flora of the oropharynx, and little is known regarding cases of these non-pathogenic Neisseria species in the lower respiratory tract. We clinically examined respiratory tract infections from which non-pathogenic Neisseria species were isolated by transtracheal aspiration (TTA). The incidence of non-pathogenic Neisseria isolated was 54 (15.7%) out of 344 episodes of respiratory tract infections with isolated microorganisms from TTA, and was 17.6%, 15.8%, 14.3% for pneumonia, acute bronchitis, and chronic lower respiratory tract infection, respectively. All 54 episodes were isolated with other microorganisms such as alpha-Streptococcus spp. (75.9%), Haemophilus influenzae (25.9%) and anaerobics (22.2%). The isolation ratio according to the age group increased at 45 years of age or more, but did not increase with the advance of age. Predisposing factors were identified such as overt aspiration, iatrogenic procedure and heavy smoking. Cases without overt aspiration that had fevers of 38 degrees C or more or hypoxemia of less than PaO2 70 torr when detecting non-pathogenic Neisseria were observed more frequently in the aged than the non-aged. The findings suggest the detection of non-pathogenic Neisseria by TTA is influenced by the host state that the fall of microorganisms from the upper to lower respiratory tract cannot be defended or excluded by mucociliary transportation disorder due to underlying disease and smoking, or deterioration of physical status other than overt or silent aspiration.

Age Factors↗