Retention of local information in generation of subjective contours.

Temporal integration characteristics of subjective contour perception was investigated, using the sequential presentation of two pairs of disks with a sector removed. In the first experiment, by matching the contrast of a "real" stimulus, the perceived contrast of the subjective contours was measured as a function of the stimulus onset asynchrony (SOA) between the two pairs of the disks. With increasing SOA, the perceived contrast decreased gradually and levelled off at the SOA of ca 372 msec (1 SD = 119 msec). In the second experiment, the perceived contrast of the inducing disks was measured as a function of SOA using the matching method. The time limit of the additive effect for the contrast perception of the inducing disks was much shorter than that for subjective contours; the critical SOA was ca 65 msec (1 SD = 36 msec). The remarkable difference of the integration time was explained by a hierarchical process; the local spatial filtering, the retention of local information, and the completion of gaps by multiplicative or AND operation.

Efficacy of trimethoprim in murine experimental infection with a thymidine kinase-deficient mutant of Escherichia coli.

The antimicrobial activity of trimethoprim is antagonized by thymidine in in vitro susceptibility tests. The purpose of this investigation was to determine whether this antagonism also occurred during experimental infection in mice, which have high serum thymidine concentrations. We derived a mutant strain of Escherichia coli, TT-48, incapable of utilizing exogenous thymidine from parent strain E. coli KC-14 and then investigated the in vitro and in vivo antimicrobial activities of trimethoprim, sulfamethoxazole, cefdinir, and ofloxacin against these strains. E. coli TT-48 lacked the activity of thymidine kinase, which catalyzes the conversion of thymidine to thymidylate, but its growth curve remained close to that of the parent strain. The MICs of all of the antimicrobial agents tested, except cefdinir, for the mutant strain were slightly inferior to those for the parent strain. The bactericidal effect of trimethoprim against the parent strain was antagonized by thymidine at concentrations of more than 1 microg/ml, while that against the mutant strain was not affected by thymidine even at the highest concentration (10 microg/ml). The therapeutic efficacy of trimethoprim in experimental murine infections was significantly higher when the mutant rather than the parent strain was used, whereas the therapeutic efficacy of cefdinir or ofloxacin, whose antimicrobial action is independent of folic acid synthesis, was the same with both strains. Unexpectedly, sulfamethoxazole also had similar efficacy against both strains. Thus, high thymidine concentrations antagonized the antimicrobial activity of trimethoprim in vitro and in vivo.

[Awareness of health and welfare planning for elderly and methods to increase awareness: based on social marketing].

To clarify the socio-psychological factors affecting awareness of health and welfare planning for the elderly, a survey of community residents was performed in the Tokyo metropolitan area. The results obtained were as follows: 1. There were three factors which affected awareness concern about health and welfare services for the elderly as a social issue: concern about the local community; and concern about the local government. 2. Two other factors which did not affect the level of awareness were: anxiety about the health and welfare services for the elderly as a personal issue; and having personal experience of nursing care. From these results, a method to increase awareness was studied based on social marketing methods. Two primary target groups for increasing awareness were identified. One target was people who have the socio-psychological factors described above. Another target was people who have the potential need for health and welfare services but who were not aware of it. That is, they have relatively high anxiety about health and welfare services for the elderly as a personal issue and have personally experienced nursing care. The method of approach for these targets were studied. For the first group, the amount of the information available seemed to be important because these persons are ready to recognize the need for planning. Therefore, efficient information channels should be selected. For the second group, approaches that generate greater consumer participation by presenting this as an efficient method for solution of the problem should be adopted.

[In vitro antimicrobial activity of a new quinolone, levofloxacin, against atypical mycobacteria].

We measured th in vitro antimicrobial activity of a new quinolone, levofloxacin (LVFX) against seven clinically isolated species of atypical mycobacteria, including 30 strains of M. avium complex. 8 of M. fortuitum, 4 of M. scrofulaceum, 2 of M. kansasii, 2 of M. gordonae, and 1 of M. chelonae (subsp chelonae). LVFX showed a potent antimicrobial activity against M. kansasii, M. gordonae and M. chelonae (subsp chelonae). In addition, it was suggested that LVFX may be effective for the treatment of infections caused by M. avium complex, since satisfactory antimicrobial activity was displayed against some strains of M. avium complex. Considering the fact that LVFX shows good concentration levers in sputum, this drug could be used in the chemotherapy against the infection with M. avium complex.

Blood levels of leukotrienes (LTC4, D4, E4, B4) in asthmatic patients during attack and remission.

To assess the contribution of the leukotrienes, LTC4, D4, E4 and B4 during bronchial asthma attacks, simultaneous determination was made of their levels in venous blood. 25 patients with bronchial asthma (15 atopic types, 10 non-atopic types) participated in this study and 4 normal controls were used. Samples were obtained using heparinized syringe from the patients before treatment. A radioimmunoassay was conducted to measure LTs after purification with a Sep-pak column and separation by HPLC. In normal subjects, the levels were less than the minimal detectable amounts. LTC4, D4, E4 and B4 during asthmatic attacks were 100 +/- 179, 88 +/- 116, 479 +/- 291, and 55 +/- 73 (Mean +/- SD) pg/ml respectively (n = 27). Peptide LTs in remission were below minimal detectable levels. LTD4 in patients with moderate attacks was significantly (p < 0.05) higher than in those with mild attacks. Peptide LTs in moderate attack exceeded those in mild attacks, although not to a statistically significant degree. No significant differences in LT during attacks could be detected in atopic or non-atopic type patients. LTs would thus appear importantly involved in asthmatic attacks in atopic and non-atopic type patients, although other chemical mediators may give rise to airway inflammation.

On the loss of apparent motion between isolated chromatic stimuli near isoluminance.

Long range apparent motion (AM) between two isolated stimuli breaks down following prolonged inspection. Time-till-breakdown (TTB) for AM between random-dot squares (red or green) on a red random-dot background was measured as a function of luminance contrast of the stimuli against the background. For the same-color (red squares on the red background) and the different-color (green squares on the red background) conditions, TTB showed clear dependence on the luminance contrast, diminishing with decreasing the contrast. Near isoluminance (luminance contrast of approx. -14 to +14%), AM for the same-color condition disappeared, but AM for the different-color condition was clearly seen and persisted for 7-14 sec. These results show that AM can be produced by color alone. Previous controversial question on the loss of long range AM near isoluminance may be explained by taking into account the contrast dependence of the breakdown effect and the experimental procedures employed.

[A study of the clinical factors which have the greatest effect on bronchial hyperresponsiveness in atopic asthma by multiple regression analysis].

We studied the clinical factors which have the greatest effect on bronchial hyperresponsiveness, with 37 atopic asthma patients (23 males and 14 females). They were from 13 to 59 years old. We measured the control value of the respiratory conductance (Grs.cont), the minimum dose of methacholine (bronchial sensitivity, Dmin), the linear slope of the Grs (= 1/Rrs) decreased (bronchial reactivity, SGrs) and SGrs/Grs.cont by the "Astograph" method (Chest 80, 600, 1981). Statistical analysis was performed by multiple regression analysis. Grs.cont, log Dmin, SGrs and SGrs/Grs.cont were regarded as objective variables. Age, onset age of asthma, period of disease, smoking history, family history of atopy, serum IgE, blood eosinophil counts, positive skin test counts, FEV1.0% and type of asthma attack (perennial or seasonal) were regarded as explanatory variables. The results were as follows: 1) The explanatory variable which showed the highest partial correlation coefficients, was the type of asthma attack in multiple regression analysis of Grs.cont and log Dmin (p < 0.05, p < 0.05). 2) Grs.cont of perennial asthma attack (0.247 +/- 0.064) was significantly lower than that of seasonal attack (0.318 +/- 0.097) (p < 0.02). Log Dmin of perennial asthma attack (-0.837 +/- 0.457) was significantly lower than that of seasonal attack (-0.254 +/- 0.429) (p < 0.005). Therefore in mild atopic asthma, the clinical factor which has the greatest effect on bronchial hyperresponsiveness is the type of asthma attack. We conclude that the existence of perennial asthma attacks is mostly related to increased bronchial hypersensitivity.

[Sputum leukotrienes in chronic airway diseases and bronchial asthma attacks].

To determine the pathogenetic role of leukotrienes in chronic airway diseases, sputum samples from patients with bronchial asthma (BA), diffuse panbronchiolitis (DPB), sinobronchial syndrome (SBS), and bronchiectasis (BE) were examined for the presence of leukotrienes (LT) C4, D4, E4, B4, all apparently derived from airway inflammatory cells. Sputum samples from 21 patients, including 10 with BA attack (5 atopic type, 5 non-atopic type) and 11 with chronic obstructive airway diseases (3 DPB, 6 SBS, and BE), were studied. Patients expectorated sputum directly into test-tubes containing 80% ethanol. Following ethanol extraction and partial purification by a C18 SEP-PAK column, LTs were further purified by high performance liquid chromatography (HPLC). Fractions from HPLC with elution times corresponding to synthetic LTC4, D4, E4, and B4 were used to quantify LTs by radioimmunoassay. Eosinophils and neutrophils in the sputum (0.5 ml) were counted following Papanicolaou staining. Percentages of eosinophils in sputum were higher in BA, while those of neutrophils were higher in DPB. Sputum levels of LTC4 were 1.2 +/- 1.6 in BA, 0.12 +/- 0.11 in SBS, and 0.42 +/- 0.14 ng/ml in DPB. Those of LTD4 were 0.21 +/- 0.27 in BA, 0.9 +/- 0.13 in DPB, and 0.10 +/- 0.07 in SBS. LTE4 levels were 5.06 +/- 3.83 in DPB and 2.66 +/- 4.32 in BA. Levels of LTB4 were 1.36 +/- 1.19 in DPB, 0.28 +/- 0.27 in BA, 0.12 +/- 0.07 in SBS, and 0.04 +/- 0.04 in BE. In asthmatics, peptide leukotriene content in sputum was higher than that in chronic airway disease patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Spectral sensitivities for illusory contour perception: a manifold linkage of chromatic and achromatic cues with the generation of contours.

Using colored inducing patterns presented as increments upon a white uniform background, the increment thresholds needed for illusory contour perception were measured as a function of the wavelength of inducing pattern. The spectral sensitivity functions were obtained with varying adaptation level and stimulus configuration, high and low background illumination, and line-based and figure-based inducing patterns. The results showed a distinctive feature between the line-based and the figure-based illusory contours. The sensitivity functions for the line-based illusory contours showed the characteristics of non-opponent mechanisms and they were shape invariant with background intensity and spatial variables. On the other hand, the sensitivity functions for the figure-based illusory contours showed non-opponent nature for low background illumination but opponent nature for high background illumination. It is suggested that the generation of illusory contours involves concurrent processing of different cues of luminance and color, and that photopic adaptation level and stimulus configuration control the degree of the contributions of chromatic and achromatic mechanisms to contour formation.

[Effects of contrast media under systemic heparinization on blood coagulation and fibrinolytic system during angiocardiography--comparison of ionic and nonionic contrast media].

Nonionic contrast media are suggested to cause increased thromboembolism (in vivo), because of less inhibitory action on blood coagulation and platelet aggregation (in vitro) as compared with ionic contrast media. Therefore, to prevent thrombotic complication, we examined whether differences in blood coagulation and fibrinolytic system between the two groups received nonionic (iopamidol) and ionic (ioxaglate) contrast media are seen in vivo when 2,500 unit heparin is administered during angiocardiography. 20 patients undergoing routine angiocardiography were randomized to two groups of 10 patients each. Blood heparin concentration, activated partial thromboplastin time, prothrombin time, thrombin-antithrombin III complex (TAT), antithrombin III, fibrinogen, alpha 2-plasmin inhibitor plasmin complex, fibrinogen and fibrin degradation product were measured at four stages during the procedure: before and 5 min after 2,500 unit bolus heparin administration, 5 min after left ventriculography, and at the end of procedure. Systemic heparinization inhibited clot formation in the presence of nonionic contrast media. TAT generations were elevated before heparinization, after heparinization, however these generations were remarkably inhibited in both groups. No remarkable differences were noted at 40 +/- 14 min duration of procedure when these parameters were compared between the two groups. Since nonionic contrast media did not activate blood coagulation and fibrinolytic system with 2,500 unit heparin administration as compared with ionic contrast media, systemic heparinization was demonstrated to be effective in the prevention of thrombotic complication.

[Effects of uro-angiographic contrast media on blood coagulation--a scanning electron microscopic study on time dependent changes of blood clot and a clinical study].

Anticoagulant activity of ionic and nonionic contrast media (CM) was investigated in vitro and in vivo. Based on the time course of FPA and TAT generations and gross examinations of the blood clots on the catheters placed in CM-blood mixtures [an 2 to 8 ratio (20% v/v)]. It was demonstrated that blood coagulation was activated during the period of 20 to 30 minutes when nonionic CM (iopamidol, iohexol) was employed, but no activation of blood coagulation was noted with ionic CM (diatrizoate, ioxaglate). Scanning electron microscopic examinations of the clots on the catheters revealed that fine fibrin meshwork fibers, in which many red blood cells were trapped in bound, were observed with nonionic CM. In contrast, no fibrin mesh was formed with ionic CM after 30 minutes. In vivo, antithrombin III and fibrinogen significantly decreased in the patients who underwent infusion of nonionic CM. Our studies confirmed that nonionic CM show weaker anticoagulant activity than do ionic CM. And these findings account for previous reported thromboembolic complications with the use of nonionic CM. Extreme caution should be therefore exercised when nonionic CM are employed during prolonged angiographic and interventional procedures.

[Effects of ionic and nonionic contrast media on the blood coagulation system, the fibrinolytic system and platelets].

Effects of ionic and nonionic contrast media (CM) on blood coagulation, fibrinolytic system and platelet function were comparatively studied in vitro. By the gross observation of blood coagulation using mixture 2:8 of each contrast media and blood, its total coagulation time was clearly short with iopamidol and iohexol, and no complete coagulation was observed with ioxaglate and diatrizoate for 180 minutes. Anticoagulant effects of all CM were confirmed by the assays of APTT, PT, thrombin time, antithrombin III, FPA, TAT and anti-Xa activity. But, the ionic high osmolar CM (diatrizoate) and low osmolar CM (ioxaglate) showed a greater anticoagulant effect than nonionic CM. Anticoagulant effect of CM on coagulation system may be mainly caused by antithrombin effect. No effects of CM on the fibrinolytic system were observed by assays of the D-dimer, plasminogen and antiplasmin. And all the contrast media produced inhibitory effects of platelet aggregation induced by ADP. Ionic CM tended to have a little stronger inhibitory effect than non-ionic CM. In conclusion, it was suggested that a greater anticoagulant effect of ioxaglate ensures potential safety for thromboembolic complication during angiographic procedure.

[Preliminary study and clinical evaluation method of ioversol in angiocardiography--establishment of safety evaluation parameters and reliability of radiographic quality evaluation].

A multi-center clinical study of a new nonionic iodinated contrast medium (ioversol) was performed in 26 patients undergoing left ventriculography (LVG) and coronary angiography (CAG) at four centers. The aims of this study were to try to establish a clinical evaluation method on contrast media in angiocardiography and to determine radiographic efficacy and safety of ioversol. The reliability of the method evaluating the radiographic quality of the contrast medium was also examined with statistical analysis. Excellent radiographic efficacy was observed with ioversol and morphological diagnosis was possible in all cases. The electrocardiograms (ST-segment deflection, T-wave amplitude, QT interval, corrected QT interval, arrhythmia and heart rate) and the hemodynamic parameters (left ventricular systolic and end diastolic pressures, left ventricular dp/dt max, aortic systolic and diastolic pressures) indicated no clinically significant changes. This study suggested that the monitoring of the ECGs and hemodynamic parameters for up to three minutes after injection of the contrast medium is sufficient for the evaluation in LVG and CAG, and that the monitoring in CAG during the first injection into each left and right coronary artery is also sufficient for the purpose. Heat sensation during injection was mild. A patient had a symptom of nausea after ioversol administration, but it was mild and transient and resolved spontaneously. There were no abnormal clinical laboratory data related to ioversol. The reliability of the radiographic quality evaluated by the individual clinical investigators was considered to be high and adaptable. However, the evaluation in the blinded cinefilms by the committee members involving all investigators would be more preferable for the higher objectivity. The study results suggest that ioversol is considered to be the efficacious and safe contrast medium for the cardiovascular angiography.