Functional anatomy of the human saccus lacrimalis

The relations between the saccus lacrimalis and different portions of the musculus orbicularis oculi were studied in orbital regions of human fetuses sectioned into numbered series. No insertions of the pars lacrimalis or Horner's muscle on the saccus were found. These muscular fibres pass along the dorsal wall of the saccus and are separated from it by the reflex tendon of the ligamentum palpebrale mediale. The only muscular fibres that insert on the saccus are those that approach the anterior face of the saccus and the fornix. The fibres that insert on the anterior face proceed from the deep bundles of the pars preseptalis of the lower eyelids, and those that insert on the fornix derive from the deep bundles of the pars preseptalis of the upper eyelid.     

Neuronal pathways from low-threshold muscle and cutaneous afferents innervating tail to trunk muscle motoneurons in the cat

We studied neuronal pathways from low-threshold muscle (group I, II) and cutaneous afferents (group A(alpha)beta) innervating the tail to motoneurons innervating trunk muscles (m. iliocostalis lumborum and m. obliquus externus abdominus) in 18 spinalized cats. Stimulation of group I muscle afferents produced excitatory postsynaptic potentials or excitatory postsynaptic potentials followed by inhibitory postsynaptic potentials in all motoneurons innervating the m. iliocostalis lumborum which showed effects (32%), and predominantly inhibitory postsynaptic potentials in motoneurons innervating the m. obliquus externus abdominus (47%). Stimulation of group I+II afferents produced significant increases of the incidence of motoneurons showing postsynaptic potentials (the notoneurons innervating the m. iliocostalis lumborum, 87%; the motoneurons innervating the m. obliquus externus abdominus, 82%). The effects of low threshold cutaneous afferents were bilateral, predominantly producing inhibitory postsynaptic potentials in motoneurons innervating both muscles. These results suggest that neuronal pathways from muscle afferents to back muscle motoneurons mainly increase the stiffness of the trunk to maintain its stability, while those to abdominal muscles help to extend the dorsal column by decreasing their activities. The results also indicate that neuronal pathways from cutaneous afferents to trunk motoneurons functionallY disconnect the tail from the trunk.     

Systemic delivery of an adenovirus expressing EBV-derived vIL-10 in mice infected with Schistosoma mansoni or Leishmania amazonensis: controversial effects on the development of pathological parameters.

Within the context of microorganism/host interactions, those which last over weeks are expected to be sensitive to more or less sustained and targeted immuno-intervention, such as delivery of cytokines known to operate as down-regulators of acute inflammatory processes. IL-10 has received growing attention as a potential tool in immunotherapy, due to its anti-inflammatory and immunosuppressive properties. Therefore, using two experimental models of long-term interactions between parasites and laboratory mice, we monitored some effects of the systemic delivery of an adenovirus (Ad) expressing EBV-derived IL-10 (vIL-10) designated Ad-vIL-10. We first monitored the vIL-10 serum level following intranasal, intraperitoneal, intramuscular and intravenous administration. The i. p. and i.v. delivery of Ad-vIL-10 allowed a high serum level of vIL-10 (= 100 ng/ml), the i.v. route leading to a more sustained expression (up to 3 weeks). As a first model of parasite/mouse interaction, Schistosoma mansoni/C57Bl/6 mouse was selected. Ad-vIL-10 delivery was performed 4 weeks after S. mansoni infection i.e. at the time of egg-laying, and several parameters were monitored: (i) number of adult worms in the mesenteric vein, (ii) number of eggs trapped in the liver and intestine, (iii) liver fibrosis, (iv) serum levels of egg-reactive antibody subclasses, (v) serum content of cytokines, and (vi) cytokine production in the supernatant of antigen-stimulated mesenteric lymph node cells. No apparent effect was observed, either on the different parasitological parameters or on fibrosis development at day 70 of infection. Surprisingly, a marked increase in both Th1 and Th2 type cytokines was observed in the sera of the Ad-vIL-10 injected animals, as well as in the supernatants of their Ag-stimulated mesenteric lymph node cells. Nevertheless, polarization of the humoral response towards a Th2 profile was demonstrated by an increase in the IgE level in the Ad-vIL-10-injected animals. As far as the second model is concerned, namely the Leishmania amazonensis /C57Bl6 mouse interactions, Ad-vIL-10 was delivered intravenously one day before subcutaneous injection of stationary promastigotes and footpad swelling was monitored over 110 days. Under these conditions, vIL-10 exhibited a biphasic effect, decreasing the lesion size at the early stages of infection, but leading to a more pronounced lesion size during the chronic phase. This observation suggests a deactivation of the macrophage host cells under the influence of vIL-10. The results are discussed in the context of immunotherapy and the paradoxical effects observed in immunointervention with vIL-10.     

Two new species of Haptoglossa from north-east England

Two new species of Haptoglossa , one zoosporic, H. northumbrica , and one aplanosporic, H. polymorphs, , were isolated from samples of manure and horse dung in north-east England. The zoosporic H. northumbrica is morphologically similar to H. dickii but differs in having slightly smaller infection gun cells with a unique internal arrangement of cones in the apical missile chamber. The thallus of the aplanosporic H. polymorpha is similar to H. heteromorpha but produces three different types of aplanospore. The smaller cysts either develop into broad, arcuate gun cells or form curved adhesive cells that have a rounded base. These curved adhesive cells have very different internal ultrastructural organization. The large cysts develop into infection cells that are morphologically similar to the curved adhesive cells, but their internal structure has not yet been observed.     

Oxygen Transport System in Children Living in the Russian Far North

We studied 654 healthy ten- to twelve-year-old children living in the Russian Far North (Taimyr peninsula) and in Siberia (town of Krasnoyarsk). The state of the body oxygenation and the systems responsible for oxygen delivery were studied according to the length of time living in the Russian Far North and season of the year. An examination of newcomer children revealed the following changes during the first year of living in the Russian Far North: an increased respiration rate and changes in its circadian rhythm; an increase in the heart rate, cardiac output, and cardiac index; an increase in the mean corpuscular volume in the red blood system; the activation of lipid peroxidation, and the changes in electrolyte balance of cells. The control mechanisms of oxygen transport system gradually stabilized during the ages of two to five years. In children living more than five years in the Russian Far North, the increased oxygen demand was met by the activation of cardiovascular and red blood systems aimed at more effective and adequate oxygen delivery to tissues.