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A programmable Laboras apparatus, consisting of an automated behavioral reaction recording system, was used to record movement activity in male rats aged one, eight, and 16 months studied in groups of 12, with subsequent determination of the numbers of neuron bodies in layer V of the motor cortex in preparations stained by the Nissl method. Different age groups were found to have different numbers of neurons in the motor cortex. The greatest number was seen in animals aged eight months. Movement activity correlated with the number of neurons. [ABSTRACT FROM AUTHOR]

Ethology, a fast developing field of animal sciences has considerable relevance in animal husbandry, agriculture, control of animal populations, pest control, medicine, wildlife biology, etc. It has made vast strides of progress during the past few decades and some of these trends are reviewed. Communication signals play a salient role in sociobiology of animal groups. Animals deploy visual, acoustic, tactile and olfactory signals during their social interactions. Among these, olfactory cues have certain specific advantages over the other modes concerned. Recently considerable attention has been focussed on chemical signals in animals, especially those of economically important forms such as insects, fishes and mammals. Regarding insects, sex pheromones, aphrodisiacs, trail markers, aggregating and alerting pheromones have been isolated in various insectan orders. The factors controlling sex pheromone behaviour and impact of pheromones on control of insect population have been elaborated. Investigations on chemical cues of lower vertebrates indicate that fishes, amphibians and reptiles deploy them in their social interactions. Pheromones modulate the schooling, reproductive and alarm response behaviour in fishes. Among mammals, urine, fecal pellets, saliva and secretions of specialised skin glands function as sources of olfactory cues. Data on histophysiology, and ultrastructure of specialised skin glands, biochemistry of their secretions have been collected. Osmetrichia, scent marking patterns and fiehmen responses and their hormonal control have been elucidated. The neuroendocrinological basis of scent marking has been made explicit. Relatively only very few of the mammalian pheromones have been isolated. The role of Primer pheromones in modulation of reproductive processes in some of the rodents and signalling pheromones in social interactions of some mammals have been elaborated. Data on olfactory cues in human social interactions indicate the presence of social pheromones. Visual signals of some insects and their role in reproductive activities have been investigated. Social postures in some rodent pests and their behavioural relevance have been studied. Acoustic signals in insects facilitate congregation, sexual attraction, aggregation and alarm responses. Further various aspects of vocalisations in birds and mammals have been investigated. Reproductive investment patterns and sex ratios in insects and parental investment in birds have been elucidated. Play behaviour and their role in behavioural development has been investigated. Etiological analysis of drug action in aggressive behaviour in certain mammals has been made. [ABSTRACT FROM AUTHOR]

Specialized integumentary glands have been observed at certain specific body regions of the common house rat, Rattus rattus. Diverse zones such as eyelid, oral angle, prepuce and circum anal possess hypertrophied skin glands. The histophysiological aspects of these integumentary glands are reported. These specialized sebaceous glands have specific behavioural relevance. [ABSTRACT FROM AUTHOR]

B-cell reactivity, as expressed in a plasma cell reaction may be part of a graft-versus-host or host-versus-graft reaction. Cell transfer experiments were able to prove this. Histological evidence is presented for the occurrence of the so-called 'allogeneic effect' during a graft-versus-host or host-versus-graft reaction in the rabbit spleen. Cell suspensions containing both T-and B-cells give rise to a cellular and a humoral immunity reaction component upon transfer to histoincompatible recipients. This can also occur during a graft-versus-host reaction. This B-cell response is T-cell dependent. [ABSTRACT FROM AUTHOR]

Two times sublethal total body-X-irradiation with weekly local thymus irradiation established a T-cell deprived experimental model in rabbits. Humoral immunity reactions in draining lymph nodes have been analyzed histologically and at the submicroscopical level after challenge with Salmonella Java vaccine, horse spleen ferritin, horse-γ-globulin, a chemical sensitizer oxazolone (2 phenyl-4-ethoxymethylene-5-oxazolone) and after skin allografting respectively. The time sequence studies in these animals with an 'isolated B-cell system' are compared with similar experiments in normal non-irradiated rabbits. The site of initiation of the thymus-independent and thymus-dependent plasma cell response is established in the lymph node. The (ultra)structural features of the antibody forming (-B-)cell precursors, the marginal zone cells, are described and discussed. The differentiating off-spring of two (sub)microscopically recognizable plasma cell lines is presented. [ABSTRACT FROM AUTHOR]

The human rete testis was examined with regard to 1) the number and distribution of entrances of seminiferous tubules, 2) the light microscopic topography and 3) details of the passages as revealed by scanning and transmission electron microscopy. In a newborn 1474 entrances were counted, approximately 50 % entering from the right and 50 % from the left of the central long axis. Three major subdivisions of the rete were distinguished and described: a septal (or interlobular) part represented by tubuli recti, a tunical (or mediastinal) part which is a true network of channels, and an extratesticular part characterized by dilatations (up to 3 mm wide) which we have called bullae retis. In SEM, cylindrical strands running from wall to wall in the tunical and extratesticular rete spaces are a prominent feature. We have called these chordae retis. They are covered by epithelium and are 5-40 μm wide and 15 to more than 100 μm long. They contain a peculiar tissue consisting of central myoid cells in a fibroelastic matrix. The smaller chordae are avascular. In the light of these findings the rete is interpreted as a highly complex myoelastic sponge. Its function is discussed. [ABSTRACT FROM AUTHOR]

The ultrastructure of the normal human rete testis was analyzed. The rete testis cavities are irregularly shaped and contain virtually no spermatozoa. Smooth muscle cells often surround the cavities. In the epithelial lining, two cell types are distinguishable. Flat, dark cells exhibit numerous slender microvilli, and numerous apical and basal microvesicles. Prismatic, lighter cells have more cell organelles, mostly polarized towards a supranuclear position. Both cell types contain variable amounts of glycogen and fat, and an occasional cilium. All cells display intricate lateral cell surfaces that possess different cell-to-cell attachment devices. Intermediate cell types are frequently found. On a morphological basis, the epithelial cells seem to be involved in the release of substances into the lumen and probably also in transport towards the base. Connective tissue elements are found subjacent to the epithelium. Scattered among the fibrocytes are typical smooth muscle cells. Expansions of some smooth muscle cells are connected to the epithelial basement membrane by a network of microfibrillar material. The smooth muscle cells may be involved in changing the shape of the rete testis channels, thus promoting the flux of the rete testis fluid. Different types of nerve fibre bundles are distinguished in the connective tissue of the rete testis which may correspond to autonomic and sensory nerves or sensory receptors. [ABSTRACT FROM AUTHOR]

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