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  • Immunohistochemistry  (4)
  • Drug self-administration  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Behavioral economics of drug self-administration (1992)
    Springer
    Psychopharmacology 107 (1992), S. 211-216 
    Details
    ISSN: 1432-2072
    Keywords: Behavioral economics ; Drug self-administration ; Reinforcer interactions ; Concurrent reinforcers ; Cigarette smoking ; Coffee drinking ; Humans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In behavioral economics, consumption of a reinforcer is determined by its price and by the price of other available reinforcers. This study examined the effects of price manipulations on the consumption of concurrently available coffee and cigarettes. During fifteen 4-h sessions, coffee and cigarettes were concurrently available according to fixed-ratio (FR) schedules of reinforcement. After consumption stabilized under a fixed ratio 100 for both reinforcers, the response requirement for each reinforcer was varied separately (i.e., FR 100, 1000 and 2500), while the response requirement for the other reinforcer was kept at 100. Increasing the FR value decreased coffee and cigarette consumption to a similar degree. Also, as the price for cigarettes increased (and consumption decreased), coffee consumption decreased; however, as the price of coffee increased, cigarette consumption did not change. These results indicate that for this setting the reinforcing effects of cigarettes and coffee were comparable but interacted asymmetrically. These findings when analyzed and quantified via economic concepts of own-price and cross-price elasticity illustrate the viability of using behavioral economics to examine drug self-administration in a choice paradigm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245139
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  • 2
    Electronic Resource
    Electronic Resource
    Forced-choice versus free-choice procedures: Caffeine self-administration in humans (1992)
    Springer
    Psychopharmacology 109 (1992), S. 85-91 
    Details
    ISSN: 1432-2072
    Keywords: Caffeine ; Coffee ; Concurrent schedules ; Drug self-administration ; Humans ; Methodology ; Reinforcement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Methodological comparisons of procedures for drug self-administration are rare. In studies examining the reinforcing effect of caffeine in humans, caffeine self-administration usually has been inferred from performance under forced-choice procedures. In the present experiment, caffeine self-administration via coffee was compared under forced-choice and free-choice conditions; i.e., when subjects were and were not required to use a minimum number of coffees. Ten moderate coffee drinkers (2–7 cups/day) were assigned to forced- and free-choice conditions using a randomized cross-over design. Under each choice condition, subjects completed six independent, double-blind trials, consisting of a 2-day exposure period followed by a 2-day test period. During exposure, subjects consumed either decaffeinated or caffeinated (100 mg/serving) coffee on day 1 and the other coffee on day 2. During the test period, subjects had concurrent access to the same decaffeinated and caffeinated coffees. Under the forced-choice condition, subjects were required to drink at least four cups of coffee per day during the test period. Under the free-choice condition, subjects did not have a minimum-cup requirement. In general, the relative rate at which subjects self-administered caffeinated versus decaffeinated coffee was similar across choice conditions, even though subjects self-administered significantly fewer cups of both coffee types under the free-choice than the forced-choice condition. These results suggest that, at least for caffeine, forced-choice and free-choice procedures produce comparable results. Whether this finding generalizes to a context in which caffeine or another drug is more robustly self-administered, remains to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245484
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  • 3
    Electronic Resource
    Electronic Resource
    The behavioral economics of concurrent drug reinforcers: a review and reanalysis of drug self-administration research (1995)
    Springer
    Psychopharmacology 118 (1995), S. 250-259 
    Details
    ISSN: 1432-2072
    Keywords: Behavioral economics ; Caffeinated coffee ; Cocaine ; Complements ; Concurrent schedules of reinforcement ; Cross-price elasticity ; Ethanol ; Etonitazene ; Drug self-administration ; Heroin ; Food ; Methadone ; Morphine ; Nicotine cigarettes ; Pentobarbital ; Phencyclidine ; Reinforcer interactions ; Substitutes ; Sucrose ; Water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In economics, goods can function as substitutes, complements, or be independent of one another. These concepts refer to increases, decreases, or no change in the consumption of one item as the price of a second item increases. This review examined whether these economic terms can be used to describe relationships between concurrently available reinforcers in drug self-administration research. Sixteen drug self-administration studies that examined the effects of concurrent reinforcers were identified through a MEDLINE search. Across these studies, the following substances were employed: caffeinated coffee, cocaine, etonitazene, ethanol, heroin, food, methadone, morphine, nicotine cigarettes, pentobarbital, phencyclidine, sucrose and water. These studies were reanalyzed and the results were shown to be consistent with these economic notions. These analyses also showed that relationships among the concurrently available reinforcers were reliable within and across studies, that concurrently available reinforcers can affect each other asymmetrically, and that the relative price may determine the magnitude of effect for substitutes. These findings suggest that these economic concepts may be useful in characterizing the type and magnitude of interactions between concurrently available reinforcers and may suggest potential mechanisms that determine these relationships.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245952
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  • 4
    Electronic Resource
    Electronic Resource
    Immunohistochemical study of seminiferous epithelium in adult bovine testis using monoclonal antibodies against Ki-67 protein and proliferating cell nuclear antigen (PCNA) (1996)
    Springer
    Cell & tissue research 283 (1996), S. 191-201 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Testis ; Seminiferous epithelium ; Proliferating cell nuclear antigen (PCNA) ; Ki-67 protein ; MIB-1 antibody ; Immunohistochemistry ; Tubular whole-mounts ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The distribution pattern of proliferating cell nuclear antigen (PCNA) and Ki-67 protein was studied in adult bovine seminiferous epithelium by means of immunohistochemistry using monoclonal antibodies. Tailoring the methodological protocol for each of the two proliferation markers was a necessary prerequisite for obtaining optimal results in tubular sections and whole-mounts. A-, I- and B-spermatogonia displayed PCNA-positive nuclei, except during meta-, ana- and telophases of mitosis. PCNA-negative nuclei in the basal tubular compartment, excluding those from non-cycling Sertoli cells, belonged to the spermatogonia precursor cell line. However, only about 30%, 45% and 47% of the respective A-, I-, B-spermatogonia had positive nuclei after exposure to the MIB-1 antibody directed against the Ki-67 protein. Spermatogonia with MIB-1-negative nuclei represented cells in the G1-phase. Both antibodies reacted intensely with the nuclei of preleptotene primary spermatocytes. PCNA reactivity was also present during leptotene through pachytene. Ki-67 protein expression was absent during leptotene and zygotene but was again encountered during pachytene and meiosis I and II. Anti-PCNA/anti-protein gene product 9.5 double-labelling indicated that the transition from spermatogonia precursor cells into A1-spermatogonia is not strictly synchronized in a given tubular segment, a possible reason for the flexibility in A-spermatogonial propagation seen in bovine seminiferous tubules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050529
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  • 5
    Electronic Resource
    Electronic Resource
    Configuration and distribution of bovine spermatogonia (1995)
    Springer
    Cell & tissue research 279 (1995), S. 277-289 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Spermatogonia ; Protein gene product (PGP) 9.5 ; Immunohistochemistry ; Tubular whole-mounts ; Spermatogonial degeneration ; Testis ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The configuration and distribution of bovine spermatogonia, preleptotene primary spermatocytes and Sertoli cells in the basal seminiferous tubular compartment have been studied by means of whole-mount preparations, immunohistochemistry and quantitative morphology. Three types of spermatogonia (Sg) can be identified. Large A-spermatogonia are irregularly distributed in the tubular periphery. Following the period of propagation of the A-spermatogonia, an interconnected meshwork of medium-sized spermatogonia with different cytogenetic potency is observed. Although the majority of the medium-sized spermatogonia are kinetically of the I type and divide to produce small B-spermatogonia, some members of the medium-sized population are seen in a growth phase and differentiate into large A-spermatogonia. These mark the beginning of a new round of spermatocytogenesis. Only one generation of B-spermatogonia divides into preleptotene primary spermatocytes. The architectural arrangement of multiplying spermatogonia in circles or rows is primarily the result of the distribution of the Sertoli cells. Spermatogonial multiplication is not strictly coordinated with the stages of the seminiferous epithelial cycle. Spermatogonial degeneration amounts on average to 3.6% and has therefore no decisive impact on the yield of primary spermatocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050283
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  • 6
    Electronic Resource
    Electronic Resource
    Configuration and distribution of bovine spermatogonia (1995)
    Springer
    Cell & tissue research 279 (1995), S. 277-289 
    Details
    ISSN: 1432-0878
    Keywords: Spermatogonia ; Protein gene product (PGP) 9.5 ; Immunohistochemistry ; Tubular wholemounts ; Spermatogonial degeneration ; Testis ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The configuration and distribution of bovine spermatogonia, preleptotene primary spermatocytes and Sertoli cells in the basal seminiferous tubular compartment have been studied by means of whole-mount preparations, immunohistochemistry and quantitative morphology. Three types of spermatogonia (Sg) can be identified. Large A-spermatogonia are irregularly distributed in the tubular periphery. Following the period of propagation of the A-spermatogonia, an interconnected meshwork of medium-sized spermatogonia with different cytogenetic potency is observed. Although the majority of the medium-sized spermatogonia are kinetically of the I type and divide to produce small B-spermatogonia, some members of the medium-sized population are seen in a growth phase and differentiate into large A-spermatogonia. These mark the beginning of a new round of spermatocytogenesis. Only one generation of B-spermatogonia divides into preleptotene primary spermatocytes. The architectural arrangement of multiplying spermatogonia in circles or rows is primarily the result of the distribution of the Sertoli cells. Spermatogonial multiplication is not strictly coordinated with the stages of the seminiferous epithelial cycle. Spermatogonial degeneration amounts on average to 3.6% and has therefore no decisive impact on the yield of primary spermatocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318484
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Immunohistochemical demonstration of nerve growth factor receptor in bovine testis (1996)
    Springer
    Cell & tissue research 285 (1996), S. 189-197 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Testis ; Nerve growth factor receptor ; Immunohistochemistry ; Ultrastructure ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Nerve growth factor receptor (low-affinity form) was demonstrated immunohistochemically in bovine testis by using a monoclonal mouse anti-human antibody. In the 7-month-old fetus and in the early postnatal testis, the peritubular and intertubular fibroblast-like mesenchymal cells showed a strong reaction. Following differentiation of these cells into Leydig and myoid peritubular cells, the nerve growth factor receptor was no longer expressed. However, peritubular and intertubular testicular fibroblasts/fibrocytes, which are also derived from mesenchymal precursors, remained positive. Additionally, the nerve growth factor receptor was demonstrated in postnatal prespermatogonia, A-spermatogonia, I-spermatogonia and members of the spermatogonia precursor cell line; B-spermatogonia remained negative. In A-spermatogonia and I-spermatogonia, the expression of the nerve growth factor receptor was cell-cycle-dependent and was mostly observed during G1-phase. Pre-embedding ultrahistochemistry with gold-conjugated antibody followed by silver-enhancement revealed that the nerve growth factor receptor was localized at the outer cell surface. The metal granules showed a regular distribution in positive spermatogonia. In testicular fibroblasts/fibrocytes the long narrow processes were preferentially decorated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050636
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