Lymphoid Organs and Blood Cells of the Caecilian Ichthyophis kohtaoensis

The present work analyzes by light microscopy circulating blood cells and lymphoid organs of the caecilian, ichthyophis kohtaoensis. Peripheral blood contains erythrocytes, thrombocytes, lymphocytes, monocytes, heterophils, easinophils and basophils. Thymus, liver and spleen are the major lymphomyeloid organs in this caecilian and there is not a haemopoietic functioning bone marrow. The results are discussed on the basis of the possible phylogenetic positions of the Apoda emphasizing their relationships to the Urodela.     

Postnatal development of the hypothalamic ventromedial nucleus: neurons and synapses

1. In this report the postnatal differentiation of the hypothalamic ventromedial nucleus (VMN) was studied. The main maturational changes detected at the fine structural level occurred between 10 and 20 days of postnatal life. 2. In 5-day-old rats the majority of neurons was undifferentiated, with rudimentary cytoplasmic organelles. Dendritic profiles presented an empty appearance due to an electron-lucent matrix and scarce content of organelles. 3. At 10 days there was a significant proliferation of cytoplasmic organelles in the perikaryon, mainly of those involved in protein biosynthesis as the rough endoplasmic reticulum (RER) and the Golgi complex. 4. After 20 days of age the VMN neurons acquired the cytological appearance of adult neurons, with well-organized RER, Golgi complexes, and pleomorphic mitochondria. Concurrent with these changes, there was a marked development of other organelles in the neuropil, which was accompanied by an increase in synaptic density and differentiation of their subsynaptic structures.     

Ultrastructural diagnosis of facial nerve schwannoma using fine needle aspiration

In a 14-year-old boy presenting with left facial nerve paralysis, physical examination revealed a soft, round mass in the floor of the left external auditory canal. A fine needle aspiration biopsy was performed to obtain material for light and electron microscopy. Several small groups of uniform, spindle-shaped neoplastic cells were present on the slides; a malignant mesenchymal tumor was considered, but a definite diagnosis could not be established under light microscopy. The ultrastructural examination revealed spindle-shaped and stellate cells with multiple parallel cytoplasmic processes lined with a well-developed basal lamina; these features are highly characteristic of a benign schwannoma.     

Properties and function of caltrin, the calcium-transport inhibitor of bull seminal plasma

Indirect immunofluorescence studies with polyclonal antibodies show that caltrin binds to the plasma membrane over the acrosome and principal tail regions of bovine spermatozoa but not to the postacrosomal area or the midpiece. Calcium influx into bovine epididymal spermatozoa maintained in a simple salt medium containing DL-beta-hydroxybutyrate is prevented by caltrin freshly prepared from bovine seminal plasma through a procedure employing only gel permeation columns. Older preparations, on the other hand, enhance calcium uptake into these cells. Caltrin freshly prepared through a purification scheme that includes a cation exchanger only induces enhancement of calcium uptake into bovine epididymal spermatozoa maintained under identical conditions. It is postulated that early during sperm transit through the female reproductive tract, caltrin bound to the sperm plasma membrane protects the sperm cells from calcium influx. As the cells enter the oviduct where meeting with the egg could take place, factors present in the surrounding milieu may cause caltrin to change from an inhibitor to an enhancer of calcium uptake. The acrosome reaction and possibly hyperactivation, two components of capacitation that require calcium influx as an initial event, then take place.     

Feeding and ranging in the Mentawai Island langur (Presbytis potenziani)

Presbytis potenziani is found only on the Mentawai Islands, Indonesia, and its ecology and feeding and ranging behavior have been little studied. I studied 10 groups ofPresbytis potenziani in the primary forests of North Pagai Island, Mentawai, Indonesia.P. potenziani used primarily the upper strata of the forests for feeding, movement, and resting. Groups remained cohesive during their daily activities, ranged between 100 to > 1000 m daily, and occupied home ranges of ≤ 40 ha. Neither sex predominantly initiated group movement. Locomotion was primarily quadrupedal, with frequent leaping. P. potenziani showed two feeding peaks, one in early morning and one during midafternoon. P. potenziani fed mainly on climbers and trees of the Dipterocarpaceae. They ate primarily leaves, but also fed on fruits and other plant parts.     

Variability in cuticular hydrocarbons and phenotypic discrimination of Ixodes ricinus populations (Acarina: Ixodidae) from Europe

The cuticular hydrocarbon composition and a stepwise discriminant analysis are used to elucidate the phenotypic relationships of 66 populations of Ixodes ricinus in Europe. The method correctly allocates Ixodes persulcatus (outgroup) populations away from the main cluster of I. ricinus samples and separates the samples into ten relatively defined clusters of specimens. Populations from Poland are inseparable from samples collected in Germany, Switzerland and the Italian Alps, while individuals from Slovakia and the Czech Republic come into separate groups of phenotypic similarity. Irish and British specimens are separated but highly related and Spanish populations show an unexpectedly high distance from the remaining clusters.