Ocular tracking of moving targets: effects of perturbing the background

Primates are able to track a moving target with their eyes, even when the target is seen against a stationary textured background. In this situation, the tracking eye movement induces motion of the background images on the retina (reafference) that competes with the motion of the target's retinal image, potentially disrupting the tracking of the target. Previous work on humans reported that brief perturbations of the background in the opposite direction to pursuit were much less disruptive than perturbations in the same direction as pursuit. Furthermore, if the background moved together with the pursuit target--so as to effectively eliminate the reafference--then the effects of a subsequent background perturbation showed less dependence on direction. This suggested that the direction selectivity to background perturbations during pursuit against a stationary background was due, at least in part, to the prior motion of the background secondary to the pursuit. We now report similar findings in monkeys, and in addition, have investigated the effect of moving the background while the animal was fixating a stationary target. In this situation, the ocular tracking responses to subsequent brief perturbations of the moving background were weaker when the perturbations were in the same direction as the prior background motion than when in the opposite direction. This suggests that the selective insensitivity to the reafferent visual input associated with pursuit across a stationary background is, at least in part, independent of pursuit per se and attributable to a progressive reduction in the sensitivity to sustained background motion.     

Effects of running exercise during recovery from hindlimb unloading on soleus muscle fibers and their spinal motoneurons in rats

The effects of hindlimb unloading and recovery with or without running exercise on morphological and metabolic properties of soleus muscle fibers and their spinal motoneurons in rats were investigated. Ten-week-old rats were hindlimb suspended for 2 weeks and thereafter were rehabilitated with or without voluntary running exercise for 2 weeks. A decreased percentage of type I fibers and atrophy of all types of fibers were observed after hindlimb unloading. In addition, decreased oxidative enzyme activity of all types of fibers was observed after hindlimb unloading. In contrast, an improvement in the decreased percentage of type I fibers, decreased fiber cross-sectional area, and decreased fiber oxidative enzyme activity was observed after recovery with running exercise, but not without running exercise. There were no changes in the number, cell body size, or oxidative enzyme activity of motoneurons innervating the soleus muscle after hindlimb unloading or recovery with or without running exercise. These results indicate that running exercise is beneficial for the recovery of the decreased percentage of type I fibers and the atrophy and decreased oxidative enzyme activity of all types of fibers in the soleus muscle induced by hindlimb unloading and that there are no changes in morphological or metabolic properties of spinal motoneurons innervating the soleus muscle following decreased or increased neuromuscular activity.     

Tacrolimus reduces urinary excretion of leukotriene E(4) and inhibits aspirin-induced asthma to threshold dose of aspirin

BACKGROUND: The exact mechanism of aspirin-induced asthma is not clear. It has been postulated that precipitation of asthma attacks by aspirin is linked to inhibition of COX activity and massive release of cysteinyl leukotriene into the airway. Tacrolimus, a macrolide-derived immunosuppressant, is used for immunosuppression in organ transplantation and also for allergic diseases such as atopic dermatitis. OBJECTIVE: We evaluated the effects of tacrolimus in aspirin-induced asthma by using a double-blind, crossover study design. METHODS: Twelve patients with aspirin-induced asthma (male:female, 3:9; mean age +/- SD, 36.7 +/- 7.2 years) received either tacrolimus (0.1 mg/kg) or placebo 2 hours before the threshold dose of oral aspirin. RESULTS: In the placebo arm, oral aspirin significantly decreased FEV 1 concomitant with significant increases in sputum eosinophilic cationic protein and urinary leukotriene E(4) levels. Tacrolimus significantly inhibited bronchoconstriction and abrogated aspirin-induced increase in both sputum eosinophilic cationic protein and urinary leukotriene E(4) levels. CONCLUSION: The current study suggested that tacrolimus inhibited bronchoconstriction to a threshold dose of aspirin by inhibition of cysteinyl leukotriene excretion.     

Prevalence of asthma in adults in Menda town rural-mountain area in Japan]

Several reports have suggested that the prevalence of asthma in adults is currently increasing. However, recent prevalence of asthma has not reported in Japan, especially in rural-mountain areas. To investigate the prevalence of asthma in adults in Japan, we conducted clinical epidemiological research on 5066 inhabitants of Menda town, in a rural-mountain area of Japan. The study population comprised 98.7% of adults in the town, including senior high school students whose age were more than 15 years old. The prevalence of asthma among adults was 3.6%. The ratio of prevalence in males to prevalence in females was 1.44. Peaks prevalences were observed in the age ranges of 15-19 and > 70 years old in males, and 15-19, 40-49 and > 70 years old in females.     

A rapid isolation technique of unmodified human T cells on a polystyrene resin column

An easy and rapid isolation technique of human T cells on a polystyrene resin particle column has been developed. The cells of the effluent fraction contained more than 90% sheep erythrocyte (SRBC) rosette-forming cells and less than 1% of cells bearing surface immunoglobulin (Ig) or peroxidase. The T cell (SRBC rosette-forming cells) recovery rate was 80%. The distribution of OKT antigen T cell subsets was essentially the same as that of T cells separated by rosette sedimentation. Cell functions such as tritiated thymidine uptake by T cells and helper activity in Ig production were also the same as that of T cells separated by SRBC rosette sedimentation. Natural killer-like activity of the T cells isolated by the present method increased more than that of T cells obtained by the conventional method. Moreover, it was free from functional modification which tends to result from stimulation such as by the SRBC antigen in the SRBC centrifugation method. The combination of a T cell population offered by the present method and B cells depleted of SRBC-binding B cells minimized background plaque formation and enabled us to quantify the plaque-forming cell number in an antigen-specific plaque-forming assay. Furthermore, these populations produced relatively pure interleukin 2 (IL 2) by stimulation of an autologous mixed lymphocyte reaction without any absorption of IL 2 produced in the same culture. It seemed to be useful to evaluate the ability of lymphocytes from normal individuals and patients to produce IL 2.     

Characteristics of the antihistamine effect of TAK-427, a novel imidazopyridazine derivative

OBJECTIVE AND DESIGN: The characteristics of the antihistamine effect of the new antiallergic compound TAK-427 were investigated. MATERIALS AND METHODS: In vitro binding assay of [(3)H] pyrilamine was performed using recombinant human histamine H(1) receptors (rhH(1)R). In vivo studies were performed in male ICR mice or Hartley guinea pigs. Drugs were administered orally 1 h before examinations. Determinations were made of histamine-induced skin reaction, ex vivo measured radioligand binding to brain and lung H(1) receptors, pentobarbital-induced sleeping time, passive cutaneous anaphylaxis (PCA) reaction, and antigen-induced itch-scratch responses (ISRs). RESULTS: TAK-427 inhibited ligand binding to rhH(1)R with an IC(50) value of 17.3 nmol/l. TAK-427 inhibited histamine-induced skin reactions in guinea pigs and mice with an ID(50) value of 0.884 and 0.450 mg/kg, p.o., respectively; significant inhibition associated with 10 mg/kg of TAK-427 was still observed 24 h after dosing in guinea pigs. TAK-427 showed as high selectivity for peripheral H(1) receptors as terfenadine and epinastine did, which was evaluated by ex vivo measured radioligand binding. Even at 300 mg/kg, TAK-427 did not affect pentobarbital-induced sleeping time in mice. TAK-427 significantly inhibited PCA in mice and guinea pigs, and also inhibited antigen-induced ISRs in guinea pigs. CONCLUSIONS: These results suggest that TAK-427 may have a long-lasting antihistamine activity with minimum sedative side effect and suppress acute phase allergic reactions.     

Sequential synthesis and secretion of pectinases by Penicillium frequentans

Penicillium frequentans synthesized eleven polygalacturonases and three pectinesterases when grown in the presence of pectin, sodium polypectate or monogalacturonic acid. When glucose was the sole carbohydrate source in the medium two of these polygalacturonases and one pectinesterase were produced. The enzymes produced under any of these conditions degraded pectic substrates to monogalacturonic acid, suggesting that this monosaccharide or its metabolites should induce the pectinolytic complex. All pectinesterases and most of the extracellular polygalacturonases were synthesized after the 2nd hour of incubation. The pectinases produced by Penicillium frequentans were not secreted at the same time but after 5 hours of incubation all of them could be detected outside the cell those detected only inside the cell were probably membrane-associated or unglycosylated forms of the extracellular pectinases.     

Disturbed pyloric motility in Ws/Ws mutant rats due to deficiency of c-kit expressing interstitial cells of Cajal

Interstitial cells of Cajal (ICC) are believed to lnitlate the basic contractile activity of the gastrointestlnal tract. Interstitial cells of Cajal express c-kit receptor tyroslne kinase and are deficient in Ws/Ws mutant rats with a small deletion of the c-kit gene . As Ws/Ws rats show remarkable bile reflux to the stomach, the contraction pressure of the pylorus was compared between Ws/Ws and control +/+ rats. The contraction pressure of the pylorus was measured using a mlcrotransducer, which was Inserted through a pln-hole in the anterlor wall of the stomach under anesthesla. The magnitude of bile reflux was estimated by measurlng the content of bile acids In the stomach. The c-kit messenger RNA-expressing cells were detected by in sltu hybrldlzatlon. Frequency and the maxlmum pressure of the contractlon were comparable between Ws/Ws and +/+ rats, but the duration of the contractlon was significantly shorter In Ws/Ws rats than In +/+ rats. The number of c-kit messenger RNA-expresslng ICC in the pylorus of Ws/Ws rats was 1.7% that of +/+ rats. The bile reflux observed in Ws/Ws rats was attributed to the decrease in the duration of the pyloric contraction, which appeared to result from the deficlency of c-kit messenger RNA-expressing ICC.     

Immunoexpression of the α subunit of a guanine nucleotide-binding protein (Go) in pulmonary neuroendocrine cells and neoplasms

The α subunit of a GTP-blndlng protein, Go, was investigated in pulmonary neuroendocrine neoplasms and fetal tissues of the lung by an immunohistochemlcal method. Positive immunostaining for the α subunit of Go (Goα) was found predominantly on the cell membrane and found occasionally in the cytoplasm. Typical carcinoids were all positively stained (9/9), and small cell carcinoma showed weaker and less frequent staining (5 positive cases in 10). Atypical carcinoids were variously stained (3/4). The tendency for obvious neuroendocrine differentiation to be immunohistochemically determined in typical carcinoids and not in small cell carcinoma is also true of staining for neuron specific enolase (NSE), chromogranin A (CG-A) and synaptophysin. In the lung, Goα-immunostaining was positive not only in nerve tissues but also in the airway epithelium. In the fetal lung, serial sections immunostained for NSE, CG-A and Goα confirmed that Goα-immunoreactive cells belong to the neuroendocrine cell population. The biological significance of Goα is unclear in normal and neoplastic lung tissues, but Goα is a useful marker of neuroendocrine cells and neoplasms of the lung.