317 results match your criteria: "Karl-Marx-University[Affiliation]"

The influence of temperature (range 15-37 degrees C) on the isometric contractions of the slow twitch soleus (SOL) and the fast twitch extensor digitorum longus (EDL) muscles of mice, rats and guinea pigs were investigated in vitro. Cooling of the bathing solution prolonged the time parameters of single twitches and tetanic contractions in a non-linear manner in both muscle types of all animals. In muscles containing predominately fast twitch fibres like the EDL of all animals cooling was followed by an increase of the single twitch tension (cold potentiation) with a maximum of 160-180% at about 20 degrees C.

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Coordination processes in a human motoneuronal pool.

Biomed Biochim Acta

September 1989

Carl-Ludwig Institute of Physiology, Karl-Marx University Leipzig, GDR.

Using two leads of a multielectrode the EMG from biceps brachii muscle in man was recorded. The test-persons were ordered to produce a sustained isometric flexion force in the elbow joint which they could control optically. In the range of about 3-5% of maximum force it was possible to identify 2-5 active motor units under this condition.

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The attempt of evaluation of motor unit in vivo force in biceps brachii muscle in man shows a methodological important fact: On principle it is impossible to measure or to calculate the contribution of a single motor unit to the force output of a certain muscle. Most of the physiological data of motor units are indicated as forces measured in isolated muscles. The effect of a muscular action in joints is a momentum always.

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The motor activity patterns of the rectus superior and obliquus superior extraocular muscles of the rabbit in response to static tilt stimulation were studied by electromyography in the unanaesthetized animal during postnatal development. During the first postnatal week the eye muscle activity showed a phasic pattern with continuous fluctuations of the activity level. The main postnatal decrease of the variability of EMG activity level occurs in the rabbit during the second week of life.

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The influence of the lack of the gravity force on contractile properties of the slow-twitch soleus (SOL) and the fast-twitch extensor digitorum longus (EDL) muscles was investigated in 3 week or 6-month-old rats suspended by their tail. In both groups suspension hypokinesia (SH) lasting 3 weeks or longer leads to a marked decrease of the mass and of the mean cross-sectional area of the SOL. The SOL of suspended animals shows decreased contraction and half-relaxation times and a lower tension of the single twitch, a decreased maximum tetanic force output, an increased fusion frequency and a decreased tetanus-half-rise time.

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Combined application of propranolol and local anesthetics: enhanced anticonvulsant action.

Biomed Biochim Acta

August 1989

Institute of Pharmacology and Toxicology, Karl Marx University, Leipzig, GDR.

The influence of the local anesthetics procaine and lidocaine on the anticonvulsant action of propranolol was investigated using the maximal electroshock seizure test in mice. Combined application markedly reduced ED50 values either of the local anesthetics or of propranolol. Selected anticonvulsants and antiarrhythmics were tested by comparison.

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The stimulation of adenylate cyclase by glucagon and isoproterenol in cell lysates of hepatocytes isolated from fetal and adult female rats were measured after pretreatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Glucagon stimulation of adenylate cyclase activation was found to decrease in the hepatocyte lysate of adult female rats. Application of guanyl-5'-yl-imidodiphosphate (GppNHp) and forskolin showed this effect to be localized on the receptor level.

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In growing billy goats, bulls and heifers, the supplementation of 10 g elementary S/kg ration dry matter reduced the daily weight gain by about 15%. The offer of 10 g S and 10 mg Mo/kg ration did not intensify growth depression. It occurred, however, when 10 g S were applied together with 3 mg Cd.

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A follow-up study of perinatally hypoxic rabbits.

Biomed Biochim Acta

July 1989

Institute of Pathological Physiology, Karl Marx University, Leipzig, GDR.

Rabbits, surviving a severe 3-hours-lasting hypoxia (FiO2 = 0.05) during the 1st day of life, grew up together with their littermates. In animals aged 10 and 20 days, respectively, the vestibular induced tonic eye deviations were investigated during tilting around the three orthogonal body axes.

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The action of the radioprotector WR 10 65 on regional function of the left ventricular muscle in ischemic injured and reperfused rat heart was investigated employing a new fiber optic based method for determination of segment shortening. In anesthetized rats exposed to regional myocardial ischemia by ligation of the left anterior descending coronary artery for 60 minutes followed by 60 minutes of reperfusion WR 10 65 applicated in a dosage of 1 mM/kg body weight intraperitoneally 30 minutes prior to ischemia induced an improvement of post ischemic recovery of segment shortening from 31% of pre-ischemic values in untreated animals to 64.6%.

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Contrary to rats, developing guinea pigs don't react with a hypertrophy of their hearts following sublethal chronical intoxication with CO (200 ppm in room air applied to the pregnant mothers and subsequently to the infant animals). Since birth weight and postnatal growth remained in normal ranges, tissue oxygenation must have been sufficient despite a concentration of 30 +/- 4.5% COHb.

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The use of long-term bone marrow cultures (LTBMC) to detect hematotoxic side effects of purging methods.

Haematol Blood Transfus

March 1990

Department of Internal Medicine, Karl-Marx-University, Leipzig, German Democratic Republic.

With a view to the establishment of purging methods it is necessary to investigate complete-remission bone marrow as the real target of purging, rather than bone marrow from healthy donors. The results of LTBMC are superior to those of GM-CFC where the hematopoietic recovery of bone marrow is concerned. One-stage LTBMC after bone marrow manipulations may reflect mixed hematopoietic/stromal effects.

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Surface immunoglobulin bearing (sIg+) cells were identified in the tortoise Agrionemys horsfieldii by indirect immunofluorescence by using class-specific antisera to tortoise IgM and IgY produced in mice. With this technique 13-23% of blood lymphocytes were found to bear surface IgM and 5-8% IgY. Spleen lymphocytes show a higher percentage of sIg+ cells: 25-52% sIgM+ and 5-20% sIgY+ lymphocytes.

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Surface immunoglobulin-bearing cells from peripheral blood, thymus, head kidney, and spleen in carp (Cyprinus carpio L.) were studied by immunoperoxidase labelling using antisera against fragments of carp IgM. Different lymphoid cell populations could be determined.

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Four groups of 8 adult male hooded rats of the Long-Evans strain were investigated before and after bilateral symmetric lesions of the nucleus reticularis pontis caudalis (RPC) in a Y-maze and in a jump test box. After dorsal (d) RPC lesions the retention of preoperatively learnt simple tasks in the Y-maze or in the jump test was not impaired whereas brightness discrimination in the Y-maze was neither retained nor relearned. Postoperative acquisition without preoperative experience was impossible for dRPC rats in any of the tests.

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Four groups of 8 adult male hooded rats of the Long-Evans strain were investigated before and after lesions of the dorsal or the ventral subdivisions of the caudal pontine reticular nucleus (RPC) in an open field test (OF) and in a neurological test program. After dorsal (d) RPC lesions all labyrinthine reflexes were extremely slowed, tactile and visual placing responses strongly reduced and the startle reflex abolished, whereas ventral (v) RPC lesions did not alter the neurological status. The dRPC rats showed strongly reduced drinking from water bottles, did not eat pellets in their home cages and lost 5% of their body weight per day.

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Long and short axis diameters of synaptic vesicles were obtained from 6 classes of presynaptic boutons found in the medial septal nucleus (MS) of the rat. The variability of vesicle size and shape was documented in diagrams and discussed with regard to their suitability as criteria of classification and their functional significance. The variability in shape, but not in size, of vesicles in synapses of Gray's type I is lower than of those in Gray's type II synapses.

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A Golgi deimpregnation study of neurons in the rhesus monkey visual cortex (areas 17 and 18).

Anat Embryol (Berl)

February 1990

Paul Flechsig Institute for Brain Research, Karl Marx University Leipzig, German Democratic Republic.

The morphological features of 298 neurons impregnated according to Golgi-Kopsch in areas 17 and 18 of Macaca mulatta were analyzed, and the same neurons were deimpregnated to visualize structural details of the somata in different types of neurons. The following cell types were investigated: Pyramidal and pyramid-like cells, spiny stellate cells, double bouquet cells, bipolar cells, chandelier cells, neurogliaform cells, basket and related cells. This procedure allows the evaluation of the nuclear-cytoplasmic proportion and the position of the nucleus besides shape and size of the cell body.

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Retinal Müller (glial) cells are thought to act as "cables" carrying spatial buffering K+ currents from the sites of neuronal release into the reservoir of the vitrous body. In order to calculate the amplitude of such currents it is necessary to know the intracellular volume fraction which is able to carry these currents. Thus, this organelle-free volume fraction was measured in transmission electron microscopic photograms of rabbit Müller cells.

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Diagnosis, long-term management and family investigations of Wilson's disease are provided by selected clinical institutions in the GDR. From 187 patients detected since 1949, 111 are alive. In spite of the principal effectiveness of penicillamine treatment, confirmed by the disappearance of most of the central nervous system symptoms and successful professional rehabilitation of many patients, insufficient therapeutic discipline, psychosocial disturbances and penicillamine side-effects forcing its substitution by zinc or triethylenetetramine dihydrochloride in 14 cases need our further attention.

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The general accepted concept about the MRF as an unspecific ascending activating system concerns only one of its multiple functions. Investigations on more than 100 hooded rats of the Long-Evans strain with small bilateral symmetric lesions in dorsal, central and ventral subnuclei of the MRF brought out the following results pointing to further important functions: 1. Each lesion type produced a different syndrome of parameter changes of the spontaneous open field behavior with some common tendencies of reduced ambulatory and exploratory activities.

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The most widely studied model of plasmacytomagenesis is the induction of plasmacytomas by intraperitoneal injections of pure alkanes such as pristane (2.6.10.

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The DNA content and the nuclear dry mass of 18 keratinized squamous cell carcinomas and their metastases, of one adamantinoma recurrence and two adenoid cystic carcinomas of the oral cavity were determined in comparison to the normal buccal mucosa using Feulgen scanning cytophotometry and interference microscopy. The squamous cell carcinomas could be classified into five groups based on their DNA distribution pattern. The nuclear dry mass and its variation were found to be different from the normal mucosal epithelial cells in all cases.

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In order to study the placental role in controlling glucose metabolism and neonatal induction of tyrosine aminotransferase in rat liver, a comparison was made between the artificially delivered-rat feto-placental unit and the newborn littermates. The immunoreactive serum insulin in the feto-placental unit remains as high as in utero for at least 1 h whereas in the newborn rat it decreases rapidly after delivery. From Caesarian section to 6 h later, in contrast to the newborn littermates, the feto-placental unit remains hyperglycaemic.

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Retinal glial (Müller) cells were grown from explants of early postnatal rabbit retinae. The resulting monolayers of flat cells were exposed to control media (containing 5.85 mM K+), and to media with enhanced K+ concentrations (10 and 20 mM) or arginine-vasopressin (AVP, 20 micrograms/ml) or epithelial growth factor (EGF, 10 ng/ml).

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