Nucleus accumbens local circuit for cue-dependent aversive learning

Response to threatening environmental stimuli requires detection and encoding of important environmental features that dictate threat. Aversive events are highly salient, which promotes associative learning about stimuli that signal this threat. The nucleus accumbens is uniquely positioned to process this salient, aversive information and promote motivated output, through plasticity on the major projection neurons in the brain area. We describe a nucleus accumbens core local circuit whereby excitatory plasticity facilitates learning and recall of discrete aversive cues. We demonstrate that putative nucleus accumbens substance P release and long-term excitatory plasticity on dopamine 2 receptor-expressing projection neurons are required for cue-dependent fear learning. Additionally, we find that fear learning and recall is dependent on distinct projection neuron subtypes. Our work demonstrates a critical role for nucleus accumbens substance P in cue-dependent aversive learning.

Restoring and immunohistological examination of Feulgen stained avian embryonic tissues using iron hematoxylin and endothelial cell specific antibody

The immunohistological method described here permits re-examination of previously Feulgen stained quail-chick chimera tissues for vascular development using the monoclonal antibody QH1 which specifically recognizes quail hemangioblastic cells. Weigert's iron hematoxylin has been used to restore faded or bleached Feulgen stained chimeric avian tissues. Species-specific differences in nuclear morphology are as evident with iron hematoxylin staining as they are with Feulgen staining.

[Nephropathic and benign cystinosis (author's transl)]

Cystinosis is a rare, autosomally and recessively inherited disorder of amino-acid metabolism with ocular involvement. Four patients with this disease are reported on. The clinical signs of the first patient, who had nephropathic cystinosis, are compared with the signs and symptoms of the benign phenotype (benign cystinosis). In both nephropathic and benign cystinosis, multiple crystals were found in the cornea and conjunctiva. In the second case a large number of crystals were demonstrated in bone-marrow smears and conjunctival sections; a chromatogram of the conjunctiva indicated the presence of cystine. Although the results of an analysis of cultured fibroblasts from this case were contradictory, an elevated cystine level appeared likely. Crystals were also found in conjunctival sections from the third case. In the fourth case it proved impossible to demonstrate crystals clearly in either the bone marrow or in conjunctival sections. There was no evidence of any other cause of the corneal or conjunctival crystals.

Primary perireticulin amyloidosis in a 14-year-old girl

A primary perireticulin amyloidosis is reported in a 14-year-old girl, which showed the symptoms of a steroid-resistant nephrotic syndrome. The diagnosis was established by biopsies of kidney and rectum. Occurrence of amyloidosis in childhood and the clinical picture are discussed and references to clinical trials carried out are given.