Intracellular study of nucleus parabrachialis and nucleus tractus solitarii interconnections

Responses of the nucleus parabrachialis (PBN) neurons to electrical stimulation of the nucleus tractus solitarii (NTS) were investigated by intracellular recording technique in anesthetized rats. Excitatory postsynaptic potentials (EPSPs) were evoked by ipsilateral NTS stimulation in 38 PBN neurons. They were considered monosynaptic because their latencies did not change with either variations in stimulus intensity or high-frequency repetitive stimulation. The latencies of EPSPs ranged from 1.2 to 6.9 ms. PBN neurons were also antidromically activated by NTS stimulation, giving a mean axonal conduction velocity of 4.6 m/s. Some of these neurons also responded with monosynaptic EPSPs to NTS stimulation. Direct stimulation of these neurons by depolarizing current pulses elicited repetitive firing with frequencies up to 350 Hz. The morphological analysis of 5 PBN neurons labeled with horseradish peroxidase (HRP) indicates that the soma were fusiform in shape, and the size varied from 163 to 783 microns 2. All neurons had 3-5 spiny primary dendrites which extended in a predominantly mediolateral direction. Axons arose from a proximal dendritic trunk, close to the soma. The results indicated that PBN is reciprocally connected with the NTS which elicits an excitatory effect on PBN neurons.     

Substance P-immunoreactive neurons in the neocortex of the rat: a subset of the glutamic acid decarboxylase-immunoreactive neurons

Substance P-immunoreactive (SP-IR) neurons are found throughout the layers of the rat neocortex. Within the somatosensory (SI) cortex these cells make up about 2% of all neurons and within area 17 about 3%. Colocalization studies reveal that the SP-IR neurons are a subset of the population immunoreactive for glutamic acid decarboxylase.     

A novel recombinant tumor necrosis factor-alpha mutant with increased anti-tumor activity and lower toxicity.

We prepared a novel recombinant tumor necrosis factor-alpha (TNF) mutant (mutant 471), in which 7 N-terminal amino-acids were deleted and Pro8Ser9Asp10 was replaced by ArgLysArg, and compared its biological activity with that of wild-type recombinant TNF. Mutant 471 had a 7-fold higher anti-tumor activity against murine L-M cells in vitro, and a higher binding activity to TNF receptors on L-M cells, than wild-type TNF. Furthermore, mutant 471 showed a higher anti-tumor effect on murine Meth A-HM tumors transplanted into BALB/c mice, with complete regression of the tumors being observed in the animals. The possible cachectin activity of mutant 471 was almost the same as that of wild-type TNF. The acute lethal toxicity of mutant 471 in beta-D-galactosamine-sensitized C3H/HeJ mice was 18 times lower than that of wild-type TNF. These results suggest that mutant 471 might be a more promising anti-cancer agent than wild-type TNF.     

Increased renal threshold of bicarbonate due to carbon dioxide retention associated with proximal renal tubular acidosis

We report a neonate who manifested type II (proximal) renal tubular acidosis (RTA). Hypoventilation secondary to hypothalamic dysfunction led to carbon dioxide retention. The consequent changes in acid base regulation are detailed and discussed.     

Trichinella infection and clinical disease

Trichinellosis is caused by ingestion of insufficiently cooked meat contaminated with infective larvae of <it>Trichinella</it> species. The clinical course is highly variable, ranging from no apparent infection to severe and even fatal disease. We report two illustrative cases of trichinellosis. Returning to Denmark a few days after having eaten roasted pork in the Republic of Serbia, a female patient suffered from severe vomiting, epigastric pain, diarrhoea, and later myalgia, generalized oedema, and prostration. A biopsy showed heavy infestation with <it>Trichinella spiralis</it>, 2000 larvae/g of muscle. Life-threatening cardiopulmonary, renal and central nervous system complications developed. The patient recovered after several months. Her husband, who also ate the pork, did not have clinical symptoms, but an increased eosinophil count and a single larva in a muscle biopsy confirmed infection. The epidemiology, clinical manifestations, diagnosis, treatment and prevention of trichinellosis are reviewed.