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Biomedical subjects

T Okubo

Publications and source records attributed to T Okubo.

At least 361 records · Page 20Linked to original sources
PubMed1990

[Quantitative evaluation of screening programs for chronic diseases].

This paper addresses an epidemiologic approach to the quantitative evaluation of screening programs for chronic diseases. A new formula is advanced for the quantitative relationship between the yield of a screening program and the natural history of chronic disease, based on the two stage model of disease progression. The formula was applied to follow-up data of the participants and the proportions of cases detected by the screening were estimated as 15.3% for all diseases and 43.8% for hypertensive disorders. The formula is useful for continuous monitoring of ongoing screening programs as well as for potential impact evaluation of hypothetical programs.

Adult↗
PubMed1990

Effect of alveolar pressure on single-breath CO diffusing capacity at mid-lung volume.

The present study examines whether changes in the alveolar pressure (PA) affect the single breath diffusing capacity for carbon monoxide (DLCO) more strongly at mid-lung volume than at total lung capacity (TLC) in normal subjects. DLCO was measured at 60%, 80% and 100% of TLC, while PA was kept at +30, 0, or -30 cm H2O by the subject's effort during the measurement of DLCO at each lung volume. The capillary blood volume (Vc) and the membrane diffusing capacity (Dm) were also determined. DLCO at zero PA was found to be higher at 100% TLC than at lower lung volumes. At PA = +30 cm H2O, DLCO at 100%, 80%, and 60% TLC decreased by 8%, 13%, and 13%, respectively, and the decreases in Vc were 2%, 10%, and 21%, respectively. However, negative PA did not cause any significant changes in DLCO or Vc at any lung volume. Also, Dm did not change at any PA. We conclude that DLCO is more affected by a positive PA at mid-lung volume than at a high lung volume, probably due to a greater decrease in Vc.

Adult↗
PubMed1990

Dose-response relationship of ozone-induced airway hyperresponsiveness in unanesthetized guinea pigs.

The effect of ozone dose (the product of ozone concentration and exposure time) on airway responsiveness was examined in unanesthetized, spontaneously breathing guinea pigs. Airway responsiveness was assessed by measuring specific airway resistance (sRaw) as a function of increasing concentration of inhaled methacholine (Mch) aerosol (the concentration of Mch required in order to double the baseline sRaw: PC200Mch). The airway responsiveness was measured before and at 5 min, 5 h, and 24 h after exposure. A 30-min exposure to 1 ppm ozone (dose 30 ppm.min) did not change PC200Mch at any time after exposure. Both a 90-min exposure to 1 ppm ozone and a 30-min exposure to 3 ppm ozone, which are identical in terms of ozone dose (90 ppm.min), decreased PC200Mch to a similar degree. A 120-min exposure to 3 ppm ozone (360 ppm.min) produced a much greater decrease of PC200Mch at 5 min and 5 h after exposure, compared with low-dose exposure. There was a significant correlation between ozone dose and the change in airway responsiveness. In all groups, the baseline sRaw was increased by approximately 50% at 5 min after exposure, but there was no correlation between the changes in PC200Mch and the baseline sRaw. This study suggests that ozone-induced airway hyperresponsiveness in guinea pigs is closely related to ozone dose.

Aerosols↗
PubMed1990

Analysis of stomach cancer incidence by histologic subtypes based on a mathematical model of multistage cancer induction and exponential growth.

A mathematical model incorporating the processes of both cancer induction and subsequent tumor growth has been developed. The model was applied to incidence data of stomach classified into histologic subtypes: papillary adenocarcinoma (PAP), well and moderately differentiated tubular adenocarcinomas (WEL and MOD), poorly differentiated adenocarcinoma (POR), mucinous adenocarcinoma (MUC) and signet-ring cell carcinoma (SIG). The multistage theory was assumed for cancer induction as in the Armitage-Doll model. For the period of growth, exponential growth was assumed and clinical surfacing was formulated as a stochastic process related to tumor diameter. The number of stages in cancer induction and the tumor growth rate were simultaneously estimated for each histologic subtype using the maximum likelihood procedure. The present model showed better fits than the Armitage-Doll model in most histologic subtypes except WEL, PAP, WEL and MOD, which are characterized as differentiated subtypes with less mucous production, showed different features from POR, MUC and SIG: 1) the number of stages was estimated to be larger, 2) the differences in incidence rates between males and females were more marked, and 3) males tended to have larger growth rates in PAP and MOD, while in POR, MUC and SIG, females had larger values. The present study showed that an analysis by histologic subtypes is of importance in stomach cancer and that the period of tumor growth should not be ignored when formulating a model of the natural history of stomach cancer.

Adenocarcinoma↗
PubMed1990

Herpes zoster in patients with polymyositis and dermatomyositis.

Twenty-two patients with polymyositis and dermatomyositis (PM-DM) were retrospectively studied with regard to development of herpes zoster. Herpes zoster occurred with high frequency in patients with PM-DM. The clinical courses of zoster infections were uneventful; no severe complications nor deaths occurred, and only one patient had post-therapeutic neuralgia. No specific therapy for this infection was necessary. Zoster tended to occur in the inactive stage of PM-DM. PM-DM patients with herpes zoster had a significantly higher incidence of antinuclear antibody. There seemed to be no relationship between steroid therapy and herpes zoster infection.

Adult↗
PubMed1990

Effects of ozone exposure on experimental asthma in guinea pigs sensitized with ovalbumin through the airway.

As ozone (O3) is known to cause airway inflammation and hyperresponsiveness, we examined the effects of O3 exposure (1, 3, or 5 ppm, 2 h) on sensitization and provocation in guinea pigs sensitized with ovalbumin (OA) through the airway. In groups exposed to O3 before sensitization, 5 ppm increased the production of IgG1 antibodies and decreased the OA sensitization threshold from 0.01 to 0.002%. In those exposed before provocation, 1, 3, or 5 ppm of O3 decreased the OA provocation threshold from 0.5 to 0.02%, and this enhancement appeared to depend on airway hyperresponsiveness. We conclude that O3 exposure may play an important role in causing asthmatic attacks rather than enhancing allergic sensitization.

Anaphylaxis↗
PubMed1990

Acute exposure to cigarette smoke induces airway hyperresponsiveness without airway inflammation in guinea pigs. Dose-response characteristics.

We examined whether acute exposure to a low dose of cigarette smoke causes an increase in airway responsiveness in guinea pigs and whether the changes in airway responsiveness are accompanied by increased vascular permeability or neutrophil influx in the trachea. Animals were divided into four groups: groups exposed to 5, 10, or 20 puffs of cigarette smoke and a control group. Airway responsiveness was assessed by measuring specific airway resistance (SRaw) as a function of increasing concentration of inhaled methacholine (Mch) aerosol immediately, 5 h, and 24 h after exposure. In parallel studies, tracheal vascular permeability was quantified by measuring the tracheal extravasation of intravenously administered Evans blue dye, and neutrophil influx into the tracheal mucosa was quantified by counting cells within whole mounts of tracheas that were stained with Giemsa. Exposure to 5 puffs of cigarette smoke caused no changes in airway responsiveness. Exposure to 10 puffs induced airway hyperresponsiveness only immediately after exposure. Exposure to 20 puffs induced airway hyperresponsiveness not only immediately but also 5 h after exposure. There was a significant correlation between the dose (puffs) of cigarette smoke and increase in airway responsiveness immediately after exposure (r = 0.77; p less than 0.001). The tracheal extravasation of intravenously administered Evans blue dye and the number of neutrophils in the tracheal mucosa did not differ significantly from the corresponding control values at any time or in any exposed group. Furthermore, none of these changes was observed in the airways distal to the trachea of any animal immediately after exposure to 20 puffs of cigarette smoke.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1990

Altered myocardial contractility and energetics in hypertrophied myocardium.

Alterations of myocardial contractility and energetics were examined in cardiac hypertrophy induced by different types of cardiac overload. Myocardial contractility was estimated by isometric contraction of isolated left ventricular papillary muscles. Myocardial energetics were assessed from ventricular myosin isoenzyme patterns obtained by pyrophosphate gel electrophoresis. Cardiac hypertrophy was induced by endurance swim-training and sustained pressure-overload by abdominal aortic constriction or volume-overload created by an arteriovenous shunt. In swim-trained hypertrophied myocardium, isometric developed tension (T) and dT/dtmax showed a tendency to increase and response of dT/dtmax to isoproterenol increased significantly as compared with sedentary rats. Training shifted the left ventricular myosin isoenzyme pattern toward VM-1, which has the highest ATPase activity. In pressure- or volume-overloaded myocardium, dT/dtmax decreased significantly and mechanical response to isoproterenol also decreased (or tended to decrease in volume-overloaded hearts) as compared with the respective sham-operated controls. In pressure- or volume-overloaded hearts, left ventricular myosin isoenzyme pattern shifted toward VM-3, which has the lowest ATPase activity. These results indicate that alterations in myocardial contractility, mechanical catecholamine responsiveness and myocardial energetics in hypertrophied myocardium do not always display the same trend, but are greatly influenced by the causes or duration of cardiac overload.

Animals↗
PubMed1990

Use of tumor diameter to estimate the growth kinetics of cancer and sensitivity of screening tests.

A statistical method has been developed that is useful for studying the relationship between the growth kinetics of malignant tumors and the detection probability either through symptoms or by screening. Mathematical models that describe the distribution of pathological variables in malignant tumors, detected after various histories of screening, are derived and parameters for detection probabilities and the growth kinetics are then estimated by the maximum likelihood procedure. By this method the probabilities of detection through symptoms as well as by screening can be estimated as functions of pathological variable(s) such as tumor size. The growth rate of tumor can also be estimated from the distribution of pathological variables. The present method was applied to gastric cancer in Japan, where an annual screening program for the disease exists. The detection probability for the indirect X-ray used as the screening test was estimated to be 0.323 x (diameter)2/[1 + 0.323 x (diameter)2]. The doubling time of gastric cancer was estimated to be 2.90 months.

Cell Cycle↗
PubMed1990

[A prospective study of access to medical services following a community-based screening program].

Participants in a multiphasic screening program, 454 men and 767 women, were followed up for a period of several months (117 days on the average) in order to evaluate their needs for medical services after screening. Five hundred sixty-two (47.1%) visited outpatient clinics in the study area; 185 as continuing visits for existing diseases (prevalent), 167 because of symptoms which developed after the screening (clinical), and 65 for further investigations of abnormal findings from the screening (screened). The ratio of prevalent to incident (= clinical + screened) cases, which is related to the duration of clinical phase, was the highest in hypertensive, thyroid, ophthalmologic disorders. This indicates that health services for prevalent cases of those diseases are needed in addition to primary and secondary preventive efforts. The proportion of screened cases in the incident cases, which reflects the ability of the screening program to detect diseases in the preclinical phase, was the highest for anemia, disorders of lipid metabolism, and hypertensive disorders. The smaller proportions in dermatologic, urologic and orthopedic disorders indicate that preventive methods for these disorders should be considered in the future. In conclusion, monitoring of screening participants by prospective follow-up and analysis by two measures proposed in this study seem promising for continuing evaluation of the effectiveness of an on-going screening program. A network system of hospitals and physicians' offices should be developed, by which the information on the visits to outpatient clinics after screening is collected and analyzed periodically for monitoring.

Adult↗
PubMed1990

Bronchoconstriction induced by spirometric maneuvers in patients with bronchial asthma.

We analyzed forced expiration maneuver-induced bronchoconstriction in 14 asthmatic patients and in seven normal subjects by breaking down the forced expiration maneuver of spirometry (the FVC maneuver) into two phases: a slow, deep inspiration to the total lung capacity (TLC) (the DI maneuver) and a forced expiration to the residual volume (RV) (the PFV maneuver). Specific airway conductance (sGaw) was measured at functional residual capacity (FRC) after each of the three maneuvers. All of the maneuvers caused the greatest bronchoconstriction immediately after completion of the maneuver. The mean decreases in the sGaw immediately after the FVC, DI, and PFV maneuvers were 45.0 +/- 6.6 (SD)% (P less than .001), 29.6 +/- 5.3% (P less than .001), and 16.7 +/- 5.3% (P less than .03), respectively. The decrease in sGaw by the FVC maneuver was very close to the combined algebraic sum of the DI maneuver and the PFV maneuver. The normal subjects did not show any changes in the sGaw by any of the maneuvers. The inhalation of albuterol almost abolished the response of bronchoconstriction to any of the three maneuvers, but inhalation of an anticholinergic agent, ipratropium bromide, did blunt the response. This study suggests that forced expiration maneuver-induced bronchoconstriction in asthmatics can be caused not only by deep inspiration to the TLC but also by forced expiration to the RV, and that the bronchoconstriction may be brought about mainly by an increase in parasympathetic activity.

Adult↗
PubMed1990

Lung cancer risk among pneumoconiosis patients in Japan, with special reference to silicotics.

A cohort study was conducted on 3335 hospitalized male pneumoconiosis patients in order to determine their lung cancer mortality. The patients were collected from 11 hospitals specializing in the treatment of pneumoconiosis and other occupational diseases and injuries, and were followed up during 1979-1983. Age-adjusted expected numbers were calculated using the mortality of the general population as a standard. A significantly high O/E ratio (4.80) for lung cancer was observed, particularly among silicotics (6.03). A slightly more than two-fold increase in risk for lung cancer was found among those who had never smoked. No dose-response relationship was found between lung cancer mortality and duration of dusty work or radiographic categories. A nested case-control analysis showed work experience in the ceramics industry to be a risk factor for lung cancer.

Adult↗
PubMed1990

[Serum type III procollagen N-terminal peptide in patients with collagen diseases].

The serum concentration of type III procollagen N-terminal peptide (P III P) level is known to reflect the activity of collagen biosynthesis. To analyze the correlation between the disease activity and serum P III P levels in collagen diseases, serum P III P levels in patients with rheumatoid arthritis (RA), progressive systemic sclerosis (PSS), and other collagen diseases were measured. In some patients serum levels of prolyl++-hydroxylase, which is an intra-cellular enzyme of collagen biosynthesis, were measured. Serum P III P levels were elevated in patients with PSS and MCTD/overlap syndrome, suggesting a high rate of collagen biosynthesis by fibroblasts. Patients with RA showed no significant elevation of serum P III P compared with normal control group. But the group of RA patients with elevated ESR and/or serum CRP values showed high levels of serum P III P. The correlation between the disease activity and serum P III P levels was observed in RA patients with positive rheumatoid factor (RF), but not patients without RF. In addition we measured P III P levels in synovial fluid of RA and osteoarthritis patients. The levels were one to three hundred times higher than serum levels, and they showed the positive correlation with serum levels, suggesting that serum P III P might be originated from synovial P III P.

Adult↗
PubMed1990

[Their titers and recognized molecules of IgG class anti-BCG antibody in sera from patients with tuberculosis].

Hypergammaglobulinemia is a frequent complication of tuberculosis. Serum levels of each class of immunoglobulin were analyzed among tuberculosis patients. Adult patients had high levels of IgG and IgA, but IgM levels were not elevated. These data suggested that antibody responses to mycobacterial antigens might be influenced by individual immune responses. In order to analyze the specific antibody responses to mycobacterial antigens, IgG class antibodies reactive with BCG proteins were enumerated by an enzyme-linked immunosorbent assay (ELISA). Patients were shown to have significantly higher a mount of IgG antibodies than healthy controls. Sera from patients with active tuberculosis had high consistently titers of antibodies. Antibody titers returned to a normal range after effective treatment, suggesting that the measurement of IgG anti-BCG antibodies would be useful for the diagnosis and follow-up of tuberculosis. In addition, serum antibody profiles were analyzed by immunoblotting. Sonicated whole BCG proteins were electrophorased and transferred to nylon sheets by Western blotting. Then the sheets were developed with sera from patients or controls. Mycobacterial cell wall contains a vast array of proteins so that comparison of the antibody profiles from different sera revealed striking individual variations. However two kinds of proteins, whose molecular sizes were 65KDa and 16KDa, were considered to be significant. The 65 KDa protein was recognized in most sera from both patients and controls. The protein may be related to a "common antigen" present in a wide variety of bacteria. These observations may shed a new light on the role of 65KDa protein in the regulation of the immune systems, for example a individual highly primed to 65KDa protein may amount an exaggerated and potentially harmful response to cross-reactive antigens from other essentially non-pathogenic bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Familial history of cancer and dietary pattern, serum cholesterol, serum protein and blood hemoglobin].

The relationships between the history of cancer in parents and the dietary pattern, serum cholesterol, serum protein and blood hemoglobin were examined to assess the possible role of lifestyle transmission in the familial aggregation of cancer. Individuals with history of cancer in parents were selected from a population of 1,221 individuals. Five age- and sex-matched controls for each case were selected from individuals, the parents of whom were alive at the age of the case parent. Intake of miso soup, pickles and milk product showed associations with the history of cancer in parents. It was also found that serum cholesterol was significantly lower in individuals with history of cancer other than stomach in the mother. Interestingly, serum protein, especially the globulin fraction, was found to be significantly lower among individuals with the history of cancer in parents. These findings suggest that lifestyle transmission might play some role in the familial aggregation of cancer.

Adult↗
PubMed1990

[In vitro synergism of two-drug combinations among cefamandole, flomoxef and imipenem against MRSA].

First of all, vancomycin (VCM) showed good antimicrobial activity against Staphylococcus aureus including methicillin-sensitive and -resistant strains. MIC90 of VCM was 1.56 micrograms/ml. Effects of different 2-drug combinations among cefamandole (CMD), flomoxef (FMOX) and imipenem (IPM), and activity of VCM alone were examined in vitro against 5 clinical isolates of methicillin-sensitive S. aureus (MSSA) and 22 isolates of methicillin-resistant S. aureus (MRSA). In a checkerboard study, synergism was observed against 4 strains of the 5 MSSA and all 22 strains of the MRSA with IPM and CMD, FMOX and IPM, and FMOX and CMD combinations. Mean MICs of these combinations were as low as one-fourth to one-tenth as those of individual drugs.

Cefmetazole↗
PubMed1989

Kinetic study of the effects of solvation on the dimerization process of alpha-chymotrypsin.

The dimeric association process of alpha-chymotrypsin has been studied with the aid of a stopped-flow spectrophotometer at various temperatures and pH values. From the temperature dependences of the forward reaction rate constant (kf) and the equilibrium dimerization constant (KD), the reaction system observed here is concluded to be entropy-driven. The increase in entropy can be attributed to the release of water molecules from both the active site and the surface part of the protein molecule during the course of dimerization. From the pH dependences of the reaction rate constants and the equilibrium constant, the reaction is concluded to depend strongly on the dissociations of the site between the carboxyl group of the aspartic acid and imidazolyl group of the histidine residues (in the higher pH region), and the site between the imidazolyl group of the histidine and the carboxyl group of the tyrosine residue (in the lower pH region), respectively.

Chymotrypsin↗