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1262. Amino acid concentrations and protein metabolism of two types of rat skeletal muscle in postprandial state and after brief starvation

Creator:
Holeček, M. and Mičuda, S.
Type:
article, model:article, and TEXT
Subject:
red and white muscle, amino acids, starvation, atrogens, and branched-chain amino acids
Language:
English
Description:
We have investigated amino acid concentrations and protein metabolism in musculus extensor digitorum longus (EDL, fasttwitch, white muscle) and musculus soleus (SOL, slow-twitch, red muscle) of rats sacrificed in the fed state or after one day of starvation. Fractional protein synthesis rates (FRPS) were measured using the flooding dose method (L-[3,4,5-3H]phenylalanine). Activities of two major proteolytic systems in muscle (the ubiquitin-proteasome and lysosomal) were examined by measurement of chymotrypsin like activity of proteasome (CTLA), expression of ubiquitin ligases atrogin-1 and muscle-ring-finger-1 (MuRF-1), and cathepsin B and L activities. Intramuscular concentrations of the most of non-essential amino acids, FRPS, CTLA and cathepsin B and L activities were in postprandial state higher in SOL when compared with EDL. The differences in atrogin-1 and MuRF-1 expression were insignificant. Starvation decreased concentrations of a number of amino acids and increased concentrations of valine, leucine, and isoleucine in blood plasma. Starvation also decreased intramuscular concentrations of a number of amino acids differently in EDL and SOL, decreased protein synthesis (by 31 % in SOL and 47 % in EDL), and increased expression of atrogin-1 and MuRF-1 in EDL. The effect of starvation on CTLA and cathepsin B and L activities was insignificant. It is concluded that slow-twitch (red) muscles have higher rates of protein turnover and may adapt better to brief starvation when compared to fast-twitch (white) muscles. This phenomenon may play a role in more pronounced atrophy of white muscles in aging and muscle wasting disorders.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

1265. Amiodaron a choroby štítné žlázy

Creator:
Jiskra, Jan and Límanová, Zdeňka
Type:
model:article, article, Text, přehledy, směrnice pro lékařskou praxi, and TEXT
Subject:
nemoci štítné žlázy--DIAGNÓZA--ETIOLOGIE, hypotyreóza--DIAGNÓZA--ETIOLOGIE, tyreotoxikóza--DIAGNÓZA--ETIOLOGIE, antiarytmika--CHEMIE--METABOLISMUS--škodlivé účinky, amiodaron--ANALOGY A DERIVÁTY--FARMAKOKINETIKA--škodlivé účinky, and klinické laboratorní techniky--STATISTIKA A ČÍSELNÉ ÚDAJE
Language:
Czech and English
Description:
Nejčastějšími a nejzávažnějšími vedlejšími účinky široce užívaného antiarytmika amiodaronu jsou tyreopatie. V článku jsou probrány patogenetické mechanismy poškození štítné žlázy, charakteristika látky, frekvence a rozdělení amiodaronových tyreopatií, zvláštnosti v jejich klinickém a laboratorním obraze a zvláštnosti jejich léčby. Je podán přehled doporučených screeningových postupů před zahájením a během léčby amiodaronem. Na závěr jsou zmíněna některá nolá perspektivní antiarytmika s předpokládanou nízkou toxicitou, jejichž výzkum je ve stadiu preklinických a klinických studií, z nichž nejnadějnějším je nejodovaný derivát amiodaronu - dronedaron., Thyroid disturbances are the most frequent and most important of the side effects of the widespread used antiarrhythmic drug - amiodarone. In this article are discussed characteristics of drug, the pathogenetic mechanisms of thyroid damage, frequency and classification of amiodarone-induced thyroid diseases, distinctions in clinical course, and the specialities in laboratory investigations and treatment. Furthermore, the recommended approaches for the screening before and during administration of amiodarone are given. Finnaly, some perspective new antiarrhythmic drugs with supposed low toxicity as non-iodinated deriváte of amiodarone - dronedarone are mentioned., Jan Jiskra, Zdenka Límanová, Lit: 23, and Souhrn: eng
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

1266. Ammonia as a pheromone in anuran tadpoles

Creator:
Manteifel, Y. B. and Kiseleva, E. I.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, amoniak, obojživelníci, housenice, ammonia, amphibians, larvae, disturbance pheromone, sensitivity, 14, and 612
Language:
English
Description:
In laboratory experiments, conspecific excretions and ammonia solutions evoked avoidance reactions in tadpoles of three anuran species, Bufo bufo, Rana temporaria, and Rana arvalis . A differential sensitivity of ammonia chemoreception was determined for two anuran species. For Bufo bufo tadpoles, these characteristics at ammonia backgr ound concentration of 0.2 mg/l lied in the range 150 % < dI/I < 500 %, and for background of 0.4 mg/l the value lied in th e range 400 % < dI/I < 500 %. For Rana temporaria tadpoles, differential threshold against ammonia background concentration of 0. 15 mg/l was close to 200 % and against background ammonia concentration of 1.1 mg/l was close to 100 %. These results suggest that such sensitivity of both anurans is sufficient for using ammonia in intra- and interspecies communication., Y. B. Manteifel, E. I. Kiseleva., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1267. AMN 082, an agonist of mGluR7, exhibits mixed anti- and proconvulsant effects in developing rats

Creator:
Pavel Mareš
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Experimentální medicína, fyziologie, epileptické záchvaty, ontogeneze, potkan, physiology, epileptic seizures, Rattus norvegicus, ontogeny, metabotropic glutamate receptors (mGlu Rs), uwanted motor efects, 14, and 616-092
Language:
English
Description:
Metabotropic glutamate receptors (mGluRs) represent a potential therapeutic target. Possible anticonvulsant action of AMN 082, an agonist of mGluR7 subtype, was studied in immature rats using pentylenetetrazol (PTZ)-induced seizures as a model. Five age groups of rats (7-, 12-, 18-, 25-day-old and adult animals) were pretreated with AMN 082 in doses of 0.5, 1, 2, and 5 mg/kg i.p. and 30 min later PTZ was administered (100 mg/kg s.c.). Controls received saline instead of the agonist. AMN 082 did not exhibit clear anticonvulsant action with the exception of suppression of the tonic phase of generalized tonic-clonic seizures (GTCS) in 12-day-old rats. Shorter latencies of GTCS after AMN 082 pretreatment indicate a proconvulsant action. Involuntary movements (mostly tremor) appeared after AMN 082 before PTZ administration, therefore we performed another experimental series with AMN 082 only (1, 2, 5, and 10 mg/kg i.p.). During 60-min observation period tremor appeared in all age groups; sensitivity to this action decreased with age from the 2 mg/kg dose in 7- and 12-day-old rats to the 10 mg/kg dose in adult rats. Mixed anti- and proconvulsant actions of AMN 082 together with unwanted motor effects makes clinical use of this drug highly improbable., Pavel Mareš., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1269. Amplitude spectra of surface waves generated by shot-hole explosions

Creator:
Holub, Karel
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, Rayleigh waves, shot-hole explosions, spectral analysis, amplitude spectra, 7, and 551
Language:
English
Description:
The object of the research was to investigate the spectral properties of Rayleigh-type surface waves, generated by shot-hole explosions during seismic refraction experiments which were carried out in the area of the Bohemian Massif and West Carpathians. The records of displacement amplitudes were spectrally analyzed and prevailing frequency fp, relative Δfr and absolute widths of the spectra Δfa were chosen as essential parameters. Whilst the prevailing frequencies were recorded within the interval f ÷ 0.80 - 3.70 Hz at the site of the observations, situated on the territory of the Bohemian Massif, the respecti ve frequency range f ÷ 0.80 - 2.6 Hz was found in the West Carpathians. Some functional dependences of the spectral amplitude parameters on epicentral distance were observed and regularities of their decrease were defined. Moreover, the influence of local seismogeological conditions at the shot point as well as at the site of observation occurred., Karel Holub., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1270. An alternative approach in hydrograph decomposition and separation of the baseflow

Creator:
Aguilar, Victor Manuel Salas , Gómez, Víctor Reyes, and Pellat, Fernando Paz
Type:
article, model:article, and TEXT
Subject:
recession curve, groundwater discharge, expo-linear model, and reservoir
Language:
Slovak
Description:
The identification of the moment when direct flow ends and baseflow begins is one of the biggest challenges of hydrological cycle modeling. The objectives of this research were: to characterize the recession curves (RC) and to separate the components of the hydrograph in a compact model. The RC were extracted from time series in three subwatersheds in Mexico. An expo-linear model was adapted and fitted to the master recession curves to find the transition point of the hydrograph and separate the baseflow. The model discriminated the RC in two decreasing ratios: one linear associated to the direct flow, and one exponential linked to the baseflow. The transition point between these two flows was obtained analytically by equaling both ratios. The derivation of a model parameter allowed to find the maximum points in the hydrometric time series, which were the criterion to separate the baseflow. The application of this model is recommended in the analysis of RC with different magnitudes from the flexibility and attachment to the fundaments of exhaustion of a reservoir.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

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