Waldenstrom's macroglobulinaemia in a bird breeder: a case history with pulmonary involvement and antibody activity of the monoclonal IgM to canary's droppings.
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A canary breeder with Waldenstrom's macroglobulinemia developed a pulmonary disease related to an interstitial infiltration by malignant B cells secreting a monoclonal IgM K. The serum monoclonal IgM was shown to possess an antibody activity to some canary's droppings antigen. This finding may help elucidate the natural course of lymphoid malignancies and the pathogenesis of rare visceral localizations. (+info)
Birth of projection neurons in the higher vocal center of the canary forebrain before, during, and after song learning.
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The higher vocal center (HVc) of the canary brain projects to two forebrain nuclei: robustus archistriatalis (RA) and area X of lobus parolfactorius. The time of birth of HVc neurons projecting to these two regions was determined by combining [3H]thymidine autoradiography and retrograde fluorogold uptake. Birds were sacrificed at 13 months of age, 4 days after fluorogold injections into area X or RA. A single injection of [3H]thymidine in ovo (embryonic day 9) labeled 76% of area X-projecting cells and 0.8% of cells projecting to RA. The great majority of RA-projecting cells were produced during posthatching development (posthatching day 10-240; P10-P240), with a peak at P60 and a hiatus at P120. HVc reaches full adult size by P240, yet at that age the production of new RA-projecting cells continued at a rate comparable to that recorded during posthatching development. Late production of neurons interconnecting two distant regions of the brain may regulate source to target cell population size. Male canaries start to sing at P40. During subsequent months, they imitate external models and their song becomes more structured and stereotyped. At sexual maturity (P240), song is stable. Three interpretations are offered: (i) neurogenesis of RA-projecting cells is related to learning, and learning continues even after achievement of pattern stability; (ii) neurogenesis of RA-projecting cells is not related to learning; (iii) the production of RA-projecting cells serves different purposes during development and after sexual maturity. (+info)
Effects of continuous noise on avian hearing and vocal development.
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Continuous loud noice was used to mask auditory feedback from vocal behavior of male canaries. Single unit techniques demonstrate partial deafness after noise exposure. Longer exposure caused greater deficits, with losses of high-frequency sensitivity. Males raised in noise to 40 days of age, then deafened surgically, thus totally deprived of auditory feedback from vocalization, developed significantly fewer song syllables than birds similarly raised but left intact, to mature in quiet sound-insulated chambers. Males left longer in noise, to sexual maturity at 200 days of age, sang at first like surgically deafend birds, but then increased their song syllable repertoire after noise termination. Thus, in spite of the considerable deafness resulting from noise exposure, the deficit in syllable repertoire was corrected, presumably as a result of restoration of the birds' ability to hear their own song. (+info)
Studies on the serological relationships between avian pox, sheep pox, goat pox and vaccinia viruses.
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By using neutralization, complement fixation and immunogel-diffusion tests, it has been demonstrated that cross-reactions occur between various avian pox viruses and between sheep pox and goat pox viruses. No such reactions were demonstrated between avian pox viruses and vaccinia virus or between avian pox and sheep pox and goat pox viruses. Furthermore, no serological relationship was demonstrable between vaccinia virus and sheep pox and goat pox viruses. (+info)
Neuronal production, migration, and differentiation in a vocal control nucleus of the adult female canary brain.
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The vocal control nucleus designated HVc (hyperstriatum ventrale, pars caudalis) of adult female canaries expands in response to systemic testosterone administration, which also induces the females to sing in a male-like manner. We became interested in the possibility of neurogenesis as a potential basis for this phenomenon. Intact adult female canaries were injected with [3H]thymidine over a 2-day period. Some birds were given testosterone implants at various times before thymidine. The birds were sacrificed 5 wk after hormone implantation, and their brains were processed for autoradiography. In parallel control experiments, some birds were given implants of cholesterol instead of testosterone. All birds showed considerable numbers of labeled neurons, glia, endothelia, and ventricular zone cells in and around HVc. Ultrastructural analysis confirmed the identity of these labeled neurons. Cholesterol- and testosterone-treated birds had similar neuronal labeling indices, which ranged from 1.8% to 4.0% in HVc. Thus, neurogenesis occurred in these adults independently of exogenous hormone treatment. Conversely, both glial and endothelial proliferation rates were markedly stimulated by exogenous testosterone treatment. We determined the origin of the thymidine-incorporating neurons by sacrificing two thymidine-treated females soon after their thymidine injections, precluding any significant migration of newly labeled cells. Analysis of these brains revealed no cells of neuronal morphology present in HVc but a very heavily labeled ventricular zone overlying HVc. We conclude that neuronal precursors exist in the HVc ventricular zone that incorporate tritiated thymidine during the S phase preceding their mitosis; after division these cells migrate into, and to some extent beyond, HVc. This ventricular zone neurogenesis seems to be a normally occurring phenomenon in intact adult female canaries. (+info)