A Chinese adolescent girl with Fechtner-like syndrome

We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients.     

Reciprocal axo-axonal synapses between the common inhibitor and excitor motoneurons in crustacean limb muscles

Summary Nerve terminals of the common inhibitor motoneuron in a crab (Eriphia spinifrons) limb closer muscle and in a crayfish (Procambarus clarkii) limb accessory flexor muscle make neuromuscular synapses with the muscle membrane (postsynaptic inhibition) as well as axo-axonal synapses with the terminals of the excitatory axon (presynaptic inhibition). That transmission is from the inhibitor to the excitor terminals at these axo-axonal synapses is indicated by the occurrence on the inhibitor membrane of presynaptic dense bars denoting sites of transmitter release. Axo-axonal synapses with the opposite polarity, in which transmission is from an excitatory onto an inhibitory terminal, were occasionally seen either adjacent to or separate from the inhibitory axo-axonal synapse. Nerve terminals of the specific inhibitor in the crayfish opener muscle were seen to make numerous axo-axonal output synapses upon excitatory nerve terminals but excitor nerve terminals were not seen to make output synapses onto inhibitor terminals. Thus reciprocal axo-axonal synapses appear to be a feature of the common inhibitor but not of the specific inhibitor. The excitor-to-inhibitor component of these reciprocal synapses may serve to limit transmitter output in the common inhibitor axon by activating glutamate_B receptors which facilitate efflux of K⁺ and hyperpolarization of the membrane.     

Culturable and nonculturable bacterial symbionts in the toxic benthic dinoflagellate Ostreopsis lenticularis.

The toxic benthic dinoflagellate Ostreopsis lenticularis hosts a variety of symbiont bacterial flora. Laboratory cultured Ostreopsis clones require the presence of symbiotic Pseudomonas/Alteromonas bacterial strains for growth and toxicity development. Three culturable bacterial strains associated with Ostreopsis were identified as Pseudomonas/Alteromonas strain 1, Pseudomonas/Alteromonas strain 2 and Acinetobacter. Denaturing gradient gel electrophoresis (DGGE) analyses of extracted Ostreopsis associated bacterial DNAs indicated that there were three culturable and four non-culturable associated bacterial strains. The results presented here are the first report of the presence of unculturable bacterial symbionts in a toxic benthic dinoflagellate. Ostreopsis lost toxicity when exposed to elevated temperatures in the field and laboratory culture and subsequently recovered toxicity at reduced temperatures. Ostreopsis associated culturable Pseudomonas/Alteromonas bacterial strains were significantly reduced in dinoflagellate cultures exposed to elevated temperatures. The decreased toxicity of O. lenticularis exposed to elevated temperatures and their subsequent recovery of toxicity in periods of reduced thermal stress may have resulted from the effects of elevated temperature on the spectrum of culturable and unculturable bacterial species interacting with their Ostreopsis host.     

Development of bilateral asymmetry in sensory innervation to lobster claws

Sensory innervation to the paired claws of the lobster. Homarus americanus, was examined during their differentiation from a bilaterally symmetric state to an asymmetric state of a slender cutter and a stout crusher claw. This was done by estimating the total number and size distribution of axons in the second nerve root which provides most (approximately 90%) of the innervation to the claws and has few, bilaterally distributed motor axons. The paired claws which are undifferentiated and resemble each other in the 1st larval stage correspondingly have nerve roots that are bilaterally symmetric. In early juvenile (4th and 5th) stages when claw type is determined, as well as in subsequent (6th, 7th, 8th, 16th) juvenile stages when the claws gradually differentiate into cutter and crusher types, the paired homologous roots are also similar. It is only in adults that asymmetry in sensory innervation is seen with more axons in the crusher root than in its cutter counterpart. The difference in number of axons between the dimorphic claws is related to differences in surface area between the claws. Thus, bilateral asymmetry in sensory innervation is acquired by the continual but differential addition of axons to the paired claws.