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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Medical microbiology and immunology 93 (1921), S. 147-162 
    ISSN: 1432-1831
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Medical microbiology and immunology 97 (1923), S. 422-432 
    ISSN: 1432-1831
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung 1. Gelatine, Agar-Agar und andere Kolloide (Gummi, lösliche Stärke) behindern den Ablauf der Bakteriophagenreaktion. 2. Die Gelatine entfaltet diesen hemmenden Einfluß sowohl im flässigen Zustand wie als Gallerte. 3. Die antagonistische Wirkung der Gelatine wächst mit der Konzentration. Zwischen gleichen Konzentrationen (Gewichtsprozenten) von Agar und Gelatine scheint kein erheblicher Unterschied zu bestehen. 4. Der antibakteriophage Effekt kommt sowohl bei 15 wie bei 37° zustande. 5. In Gelatine- oder Agar-Gallerten manifestiert sich die Schutzwirkung des Kolloids dadurch, daß eingesäte Keime trotz des Lysingehaltes der Gallerten zu Kolonien auswachsen, falls dieser Lysingehalt eine bestimmte Grenze nicht überschreitet. Die Lysinkonzentration, gegen welche die Gelatine die wuchernden Bakterien schützt, rückt um so weiter hinauf, je mehr Gelatine das Nährsubstrat enthält. 6. In flüssigen Gelatinemedien variiert die Intensität der Schutzwirkung ebenfalls mit der Gelatinekonzentration. Erst 6% Gelatine ermöglichen die Gasbildung aus Glucose durch Bact. coli. Eine Beeinflussung der Bakterien durch das Lysin findet aber auch in den höchsten Gelatinekonzentrationen statt und äußert sich durch Verklumpung der Mikroben, Lysinproduktion und durch die Entstelung lysinogener und resistenter Rassen. 7. Am stärksten behindert flüssige Gelatineden Endakt der Bakteriophagenreaktion, die Lyse. Es wird diskutiert, wie sich aus dieser Tatsache und aus den die Bakteriophagenreaktion begleitenden Agglutinationserscheinungen die Annahme einer (dystrophischen) Membranläsion ableiten läßt. 8. Da in flüssiger Galatine die Bakteriolyse ausbleibt, die Lysinproduktion aber fast ebenso lebhaft ist wie in Bouillon, erscheint die Hypothese von der Lysinentstehung durch Bakterienzerfall derzeit unhaltbar.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 15 (1972), S. 89-94 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A three months old clone of 76 asexually produced F2 Heterostegina depressa D'Obbigny, 1826 (Foraminifera) was subdivided into two groups which were cultivated for 5 months, one at 300 lux, the other at 600 lux. Nourishment was provided by symbiotic photosynthesizing algae. The 300-lux group added 1 whorl, the 600-lux group added 1/2 a whorl during the experiment, suggesting that the first group was nearer the optimum for growth than the second. Growth rates reacted but slowly to changes in environmental conditions. Also, specimens within the same culture dish showed great differences in response. In the 600-lux group, many specimens ceased to grow entirely, while others continued. Cessation of growth tends to produce a rounded test shape, by filling-in of the apertural angle, while rapid growth tends to be correlated with “flaring” tests (i.e., tests with an open spiral). In addition, there is a trend toward increased flaring during normal ontogenetic development. Shell damage is greater in rapidly growing individuals; walls are apparently thicker in slowly growing and in resting individuals. Ecological interpretation of morphological characteristics is hampered by: (1) a lag effect between growth response and environmental change; (2) slowing or termination of growth under stressful conditions with corresponding minor changes in morphology; (3) great variation in response between sibling individuals within the same culture dish; (4) aging effects.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 1 (1922), S. 628-628 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 1 (1922), S. 949-950 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1041
    Keywords: Oral antidiabetic drug ; butylbiguanide ; pharmacokinetics ; two-compartment open model ; plasma concentration ; liver concentration ; intestine concentration ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 50 mg14C-Butylbiguanide was administered intravenously to 4 diabetic patients and 100 mg14C-butylbiguanide orally to 5 further diabetics. The concentrations of the drug in plasma, intestinal fluid, intestinal epithelium and liver tissue were determined and the renal excretion of the biguanide measured. Irregularities in the plasma concentration curve were observed which appeared as systematic deviations from the ideal curve of a biexponential function. Because these deviations occurred only in the middle phase of the plasma concentration curve, it was nevertheless possible to calculate the pharmacokinetic parameters of butylbiguanide by use of a two-compartment open model. The principal pharmacokinetic parameters were determined according to this model after intravenous dosing and the following mean values were obtained:t 1/2 (β)=4.6 h (β=0.15 h−1),C P 0 =0.85µg/ml,V D =218 l,V T =157 l,V P =62 l,k 12=0.69 h−1,k 21=0.44 h−1,k el =0.54 h−1. Within 48 h after administration, an average of 72.4% of the intravenous and 74.4% of the oral dose had been excreted in the urine. Total clearance (Cl tot) averaged 536 ml/min and renal clearance (Cl ren) 393 ml/min. High concentrations of butylbiguanide were observed in the intestinal fluid (100–700 mg/ml) 20–40 min after oral administration. It was found that the drug accumulates in intestinal fluid, intestinal epithelium and liver tissue, and that it is secreted into the intestinal lumen. The concentrations of butylbiguanide in intestinal and liver tissue were 10–46 times higher than in plasma. The secretion of biguanide into the intestinal lumen may occur via the bile or the intestinal mucosa, but there is no evidence of significant biliary excretion of butylbiguanide.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 351 (1974), S. 133-145 
    ISSN: 1432-2013
    Keywords: Smooth Muscle ; Pacemaker Activity ; Frog Stomach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Wick and pressure electrode recording were used to locate the sites where spontaneous activity originates in isolated bundles of the circular smooth muscle layer of frog stomach. In long bundles up to three pacemaker regions were found to be active. Electrical activity of pacemaker regions as recorded with pressure electrodes is characterized by a distinct prepotential which has not been observed to precede action potentials of other regions of the bundle. Pacemaker sites are up to 8 mm away from each other. They appear to be spatially fixed and do not shift with time. When pacemaker regions were excised, we did not observe spontaneous activity in the remaining segments. Stimuli which usually induce activity in latent pacemaker regions are ineffective in such segments. Along the circumference of intact muscle rings of the stomach also three pacemaker regions have been located. Pacamaker frequency increases in aboral direction and is one per minute in the fundus region and 6 per min in the pyloric region.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 332 (1972), S. 127-145 
    ISSN: 1432-2013
    Keywords: Cerebrospinal Fluid ; Control of Respiration ; Central Chemoreceptors ; Brain Extracellular Fluid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The extracellular hydrogen ion concentration of the brain cannot be determined by direct measurement. For experiments, in which the composition of the cerebrospinal fluid is varied independently of the composition of the blood, a mathematical model is proposed which allows approximate calculation of the extracellular pH from acid-base parameters of the blood and the cerebrospinal fluid. The model is based on former investigations regarding the diffusion of CO2 and bicarbonate in brain tissue. Cerebral blood flow is considered as a function of the arterial CO2 tension. For simplification homogenous perfusion has been assumed. The theoretical model is valid for stationary conditions only. Solutions of the model indicate that under the conditions specified above the extracellular pH is a function of the distance from the brain surface. The cerebrospinal fluid composition influences the extracellular hydrogen ion concentration not farther than 400–500 μm below the surface. It has been concluded that structures reacting to variations of the hydrogen ion concentration in the cerebrospinal fluid must be located within this distance from the surface. The central chemoreceptors of the respiratory system which in the cat respond to changes in cerebrospinal fluid pH locally limited to the ventral surface of the medulla, are thus very probably not identical with the medullary respiratory centres which have to be assumed as being located at a greater depth.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 332 (1972), S. 146-170 
    ISSN: 1432-2013
    Keywords: Cerebrospinal Fluid ; Control of Respiration ; Central Chemoreceptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In cats lightly anesthetized with chloralose-urethane, vagal and carotid nerves dissected, the ventral surface of the medulla oblongata was perfused with mock CSF solutions. The pH of the fluids was varied by altering either the bicarbonate concentration or the CO2 pressure. During each period of perfusion steady stateP A CO2 response curves of respiration were recorded. Tidal volume, respiratory frequency, and ventilation were plotted against a) the alveolar CO2 pressure, b) the pH of the perfusion fluids (pHCSF), and c) the pH in the extracellular space of the medulla (pHe). pHe was calculated from the acid base parameters of the blood and the mock CSF by means of a mathematical model described by Berndt, Berger and Mückenhoff (1972). Under the conditions specified above respiration was neither a unique function ofP A CO2 nor of pHCSF. In a single experiment, severalP A CO2 response curves could be recorded, the number and position of which depended upon the number and the composition of the fluids simultaneously applied to the medullary surface. Similarly, pHCSF response curves could be constructed, the position and course of which was determined by theP A CO2. On the other hand, respiration could be shown to be an almost unique function of the medullary extracellular pH—irrespective of whether pHe was changed by alteringP A CO2 or pHCSF—ifV T or  were platted against the pHe values located at a depth of 200–400 μm below the ventral medullary surface. A worse correlation was obtained between respiration and pHe at smaller or greater depth. It is concluded that the effects on respiration of changes in the CO2 pressure of the blood or in the bicarbonate concentration and the CO2 pressure of the CSF can be explained by their influence on the extracellular hydrogen ion concentration in the medulla. The chemosensitive structures responding to the hydrogen ion concentration have to be assumed at a location less than 1 mm below the ventral medullary surface.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 332 (1972), S. 184-197 
    ISSN: 1432-2013
    Keywords: Control of Respiration ; Central Chemoreceptors ; Decerebration ; Anesthesia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ventilatory response to changes in the extracellular pH in the medullary tissue (pH e ) was studied in decerebrate cats and in cats anesthetized with chloralose-urethane. pH e was varied by changing theP ACO2 and by perfusion of the ventral medullary surface with solutions of different bicarbonate concentrations. For comparison,P ACO2 response curves of respiration were recorded in the decerebrate animals without simultaneous perfusion. 1. TheP ACO2 response curves ofV T obtained during perfusion of the ventral medullary surface with mock CSF show a smaller slope than the control curves recorded without perfusion. 2. The frequency response to changes inP ACO2 resembles the response obtained under control conditions only during alkaline perfusion (pH 7.6–7.8). More acid perfusates cause a decrease of frequency, which is probably due to their effect on calcium ionization. 3. During perfusion, ventilation does not reach the maximal values observed under control conditions. This is mainly caused by the diminished frequency response. 4. A similar behaviour ofV T ,f andV is observed in anethetized cats. However,f andV, less obviouslyV T , are distinctly diminished as compared with the decerebrate animals. 5. The pH e -response ofV T is not diminished during anesthesia, which is attributed to a local wash-out ot the narcotics by the perfusion. Frequency response and ventilatory response, however, are reduced as compared with decrerebrate cats.
    Type of Medium: Electronic Resource
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