Cyclic AMP-dependent modulation of vesicular monoamine transport in pheochromocytoma cells

Cyclic AMP (cAMP) is well known to enhance tyrosine hydroxylase activity in PC12 cells. We were able to demonstrate, however, that the cellular dopamine level in PC12 was lowered by dibutyryl cAMP. Furthermore, the decrease in the cellular level of dopamine was accompanied by about a 10-fold increase in the medium. The aim of this work was to elucidate the effect of cAMP on catecholamine transport. Dibutyryl cAMP did not induce exocytotic release of norepinephrine but rather inhibited its uptake. As with forskolin and cholera toxin, physiological signaling molecules such as vasoactive intestinal polypeptide (VIP) and AMP, for which PC12 cells are known to have receptors linked to activation of adenylate cyclase, also inhibited norepinephrine uptake. The inhibitory effects of dibutyryl cAMP, VIP, and AMP were dose dependent, and EC50 values were estimated to be 100 microM, 10 nM, and 1.0 microM, respectively. The inhibition profile of dibutyryl cAMP over the time course of norepinephrine uptake was biphasic: inhibition became clearly detectable after the cytosolic pool of norepinephrine had been saturated. This profile is similar to that of reserpine. Nomifensine, however, inhibited uptake at a rather constant rate throughout the entire time course. The ATP-dependent serotonin uptake by digitonin-permeabilized cells was lowered to approximately 50% that of the control by dibutyryl cAMP treatment before permeabilization, indicating inhibition of vesicular monoamine transport. This effect was also dependent on a dibutyryl cAMP concentration with an EC50 of < or = 100 microM.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduction of Gordon-Haus effect on dark solitons by means ofnonlinear gain

Transmission control of dark solitons against various perturbations is possible using amplifiers with nonlinear gain. The noise-induced timing jitter (the Gordon-Haus effect) of dark solitons is shown to be reduced significantly by this method     

MR imaging of idiopathic trigeminal neuralgia: correlation with non-surgical therapy

Urinary drainage by indwelling double J ureteral stent is well documented in the urologic literature. We used these stents in 91 patients. The majority of stents were placed endoscopically (68%). Indications were: -Ureteral obstruction (39 cases) such as tuberculous ureteral strictures, obstruction due to urolithiasis and pelvic malignancies. -Upper urinary tract surgery (29 cases) mainly pyeloplasty, pyelolithotomy, ureterovaginal fistula repair and ureteroneocystostomy. -Adjunct to endourologic treatment (16 cases) such as ureteroscopy and endopyelotomy. -Preparation for extracorporeal lithotripsy (7 cases). The complication rate associated with placement of double J stents was minimal (6.6%). The major complication was migration (3 cases). The average drainage time was 5.8 weeks. In view of these results we conclude that double J stent is safe, effective and has minimal complications.     

Direct Decomposition of NO on Ba/Ba–Y–O Catalyst

Direct decomposition and storage of nitric oxide (NO) on Ba–Y mixed oxide with four different catalysts, Ba₃Y₄O₉, BaY₂O₄, BaO/Y₂O₃ and Ba_0.5/BaY₂O₄ were investigated. Among the examined phases, it was found that Ba_0.5/BaY₂O₄ which is obtained by decomposition of Ba₃Y₄O₉ in helium at 1123 K shows relatively high NO decomposition activity at high temperature and a large capacity for NO storage at low temperature. XRD measurement suggests the formation of nano sized barium particles on BaY₂O₄ and it is suggested that Ba nano size particles play an important role for NO storage and the direct decomposition activity.     

Low temperature CO pulse adsorption for the determination of Pt particle size in a Pt/cerium-based oxide catalyst

Unexpectedly large amounts of CO adsorption have resulted from a pulse adsorption experiment at 323 K, giving about 300% Pt dispersion in a Pt/cerium-based oxide catalyst. An in situ diffuse reflectance infrared Fourier transform spectroscopic investigation on a Pt/cerium-based oxide during CO adsorption has revealed that carbonate species on the cerium oxide surface are responsible for the unrealistically large CO adsorption at 323 K, as a result of CO spillover. Lowering the temperature to 195 K considerably diminished the amount of CO adsorption. The size of the Pt particles in the Pt/cerium-based oxide catalyst was determined by CO pulse adsorption at 195 K and showed good agreement with the particle size determined by X-ray diffraction and low energy ion scattering. This indicates that CO pulse adsorption at 195 K is a useful technique to reliably estimate the Pt particle size in a Pt/cerium-based oxide catalyst.     

Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1996), III. Secular changes in susceptibility]

Susceptibilities to various antimicrobial agents were examined for Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella spp., and Pseudomonas aeruginosa that were isolated from patients with urinary tract infections (UTIs) in 10 hospitals during June 1996 to May 1997, and the results were compared with those obtained during the same period in earlier years. 1. E. faecalis Among E. faecalis strains, those with high susceptibilities to ampicillin and minocycline appeared to have decreased in the latest study period. 2. S. aureus To almost antimicrobial agents, S. aureus isolated from uncomplicated UTIs showed low susceptibilities. But the MIC50s of those agents for S. aureus from complicated UTIs have changed better state. Particularly, the MIC50s of imipenem and clindamycin were 0.125 microgram/ml or below in the latest period for the first time in our history. 3. E. coli The susceptibilities to piperacillin and quinolones of E. coli isolated from uncomplicated UTIs were better than those isolated from complicated UTIs. 4. Klebsiella spp. The susceptibilities to almost antimicrobial agents of Klebsiella spp. have been better during the latest period, compared to those during period of 1995-1996, but to ofloxacin and ciprofloxacin have appeared to have been lower. 5. P. aeruginosa The susceptibilities to quinolones of P. aeruginosa have been better during the latest period compared those during periods of 1995-1996. But, the susceptibilities to cefozopran, carbapenems and monobactams of P. aeruginosa isolated from complicated UTIs appeared to have been lower. These susceptibility changes should be utilized in determining clinical treatments.     

Construction Engineering Approach for Lunar Base Development

Studies on lunar base construction conducted by the writers' research group are summarized. A desirable lunar base design was first discussed by employing a systems engineering approach and by defining an evolutionary scenario, which emphasized resource utilization. Several lunar-base-related concepts were examined from the viewpoint of construction engineering including construction materials, structural design, and construction methods. The research also addressed resource utilization for the production of oxygen and construction materials. A commericial approach toward future lunar development is proposed.     

The significance of arterial chemotherapy for multiple hepatic metastases from colorectal carcinoma

Controversy persists with regard to the diagnosis and treatment of the acute scrotum in children. The differential diagnosis includes torsion of the testis, torsion of one of the appendices testis and epididymo-orchitis. Clinical differentiation is notoriously difficult and our policy has been to explore the scrotum of all who present with signs of an acute scrotum. The medical records of 199 boys aged less than 13 years who presented with an acute scrotum at Red Cross War Memorial Children's Hospital in Cape Town during the period 1970-1996 were retrospectively reviewed. Diagnosis was made clinically in all cases. Sixty-two boys (31%) were found on exploration to have torsion of the testis (mean age 6.3 years), the left side being affecting 2.5 times more frequently than the right (1 neonate had bilateral torsion), 62 (31%) had torsion of testicular appendages and 56 (28%) had epididymo-orchitis. Nineteen were grouped separately and 13 (6.5%) of these were treated conservatively. Boys needing an orchidectomy (N = 38) for testicular torsion presented three times later than those who did not (48 v. 16.5 hours). Successful conservation of the testis was directly related to the time interval of symptom development and surgical derotation. Boys with torsion of a testicular appendage presented later (mean 51 hours) and were older (mean 10 years) than boys in the other two groups. Those with epididymo-orchitis were younger (mean 3.3 years) and 40% were younger than 1 year. Only in one-third was there any clinical supportive evidence of the diagnosis. Surgical complications were infrequent. We advocate expedient surgical exploration and derotation with contralateral orchidopexy, since clinical differentiation between torsion of the testis, testicular appendages and epididymo-orchitis is inexact, even with highly specialised investigation such as Doppler ultrasound and radionuclide scanning, which may not be widely available, may delay definitive treatment and suggest a lack of urgency where time is of the essence.     

Alterations in K+ evoked profiles of neurotransmitter and neuromodulator amino acids after focal ischemia-reperfusion

e present evidence that nestmate discrimination in the eusocial paper wasp, Polistes dominulus, is context dependent. We compared aggression levels between nestmates and non-nestmates in dyads consisting of a pair of either nestmates or non-nestmates, and triads consisting of either three nestmates, three non-nestmates, or two nestmates and a non-nestmate. In 130 of the 237 total trials, a nest fragment (containing both brood and eggs) from the nest of some, all or none of the interactants was placed into the interaction arena. Polistes dominulus workers recognized and discriminated nestmates from non-nestmates, familiar from unfamiliar nest material and neighbours from non-neighbours. These findings suggest that nestmate and neighbour discrimination are context dependent: discrimination occurs when either the presence of a nestmate or a familiar nest fragment indicate the proximity of the colony. The context-dependent variation in aggression levels is best described by multiple, context-dependent shifts in an acceptance threshold. Thus this study provides the most extensive, critical support yet obtained for Reeve's (1989, American Naturalist, 133, 407-435) optimal acceptance threshold model. Copyright 1998 The Association for the Study of Animal Behaviour