Imaging neuromuscular junctions by confocal fluorescence microscopy: individual endplates seen in whole muscles with vital intracellular staining of the nerve terminals

The mammalian neuromuscular junction has been extensively studied by different methods to understand better the biological aspects of its normal development, ageing and pathological conditions, such as disorders of neuromuscular transmission. In the present report, a new technique is described that combines confocal microscopy with the use of a vital nerve terminal dye (4-Di-2-ASP) and rhodamine-alpha-bungarotoxin to stain postsynaptic acetylcholine receptors in the same endplate. Nerve terminals in the sternomastoid muscles of living adult mice were stained with 4-Di-2-ASP, which labels intracellular compartments of the nerve terminal containing mitochondria. Slides of these muscles were viewed by confocal microscopy and images were stored on magnetic optical discs. This procedure was compatible with subsequent acetylcholine receptor staining with rhodamine-α-bungarotoxin and observation under the confocal microscope. Classical features of the adult neuromuscular junction were displayed, such as the branched-pattern distribution of the nerve terminals and receptors and their complete colocalisation. In addition, nerve fibres from intramuscular nerve branches with their neighbouring cells, nuclei and muscle fibre striations could also be visualised. We conclude that the present technique can complement existing methods of investigation of nerve terminal anatomy and pathology, particularly where preservation of 3-dimensional relationships is required and intracellular disturbances involving mitochondrial organisation, such as ageing or other degenerative disorders, may be present.     

Alcohol, Drugs and Traffic Safety

This paper reviews existing empirical evidence on the possible influence of a wide range of psychotropic substances on driving ability. Substances which are considered include alcohol; antidepressants; sedatives and hypnotics; stimulants; opiates; cannabis; anaesthetics. Data are much richer in some of these areas than others. Different research approaches are outlined. Legislative, medico-legal and prevention aspects are briefly noted.     

Low protein alimentation normalizes renal haemodynamic response to acute protein ingestion in type 1 diabetic children

The effect of an acute protein load (2 g kg-1 bodyweight [BW]) was studied in nine type 1 diabetic children. Patients were maintained on two different dietary regimens. In study one, patients were on a high protein diet providing from 2.7 to 1.8 g of protein/kg of BW per day. In study two, patients were reevaluated after three weeks of a diet providing from 1.0 to 1.2 g kg-1 of BW per day of protein. In study one (High Protein Diet), we failed to observe any rise in GFR and RPF following the protein meal (137 +/- 21 basal vs. 110 +/- 14 and 472 +/- 93 basal vs. 494 +/- 93 ml/1.73 m2 of SA min-1 at 60 min. This is in contrast with results from seven age matched controls consuming a free diet, which showed a significant rise in both GFR and RPF. In study two (low protein diet), basal GFR was significantly reduced. However after the protein load, both GFR (92 +/- 11 vs. 126 +/- 18 ml/1.73 m2 of SA min-1) and RPF (467 +/- 83 vs. 705 +/- 102 ml/1.73 m2 min-1) rose significantly (P less than 0.05 vs. basal). The data indicate that: 1. short term protein restriction reduces significantly GFR in type 1 diabetic children; 2. diabetic children maintained on an high protein intake show an altered haemodynamic response to protein ingestion; 3. a normal response to protein ingestion can be restored by short term dietary protein restriction.     

Peptic ulcer in the elderly—a double-blind, short-term study comparing nizatidine 300 mg with ranitidine 300 mg

This was a randomized, double-blind, multicentre, short-term study comparing ranitidine and nizatidine at the standard dosages of 300 mg at bedtime. In 49 centres in Italy, all peptic ulcer patients aged over 65 years and with endoscopically documented acute disease were considered eligible for the study. Clinical check-ups were repeated every 3 weeks, while the endoscopic and biochemical assessments were scheduled at 6 and (in unhealed patients) 12 weeks. Statistics: chi-squared test, Fisher's exact test, Student t-test for unpaired data. The study included 170 duodenal ulcer and 75 gastric ulcer patients. Of these, 83/17 duodenal ulcer and 38/75 gastric ulcer patients were treated with nizatidine 300 mg and the remainder with ranitidine 300 mg. The groups were well-matched for common clinical data. Eight patients dropped out. Healing rates at 6 and 12 weeks were 81.9% and 91.5% for nizatidine-treated duodenal ulcer patients versus 78.1% and 94.2% for ranitidinetreated duodenal ulcer cases (P: N.S.); 6 and 12-week healing rates were 76.3% and 89.5% for nizatidinetreated gastric ulcer patients versus 67.6% and 83.8% for ranitidine-treated gastric ulcer patients (P: N.S.). No slow healing risk factors were found. Only minor adverse events were registered. In conclusion: ranitidine 300 mg and nizatidine 300 mg both proved effective and safe in the treatment of acute peptic ulceration in the elderly.