cAMP controls a trafficking mechanism that maintains the neuron specificity and subcellular placement of electrical synapses

Electrical synapses are established between specific neurons and within distinct subcellular compartments, but the mechanisms that direct gap junction assembly in the nervous system are largely unknown. Here, we show that a developmental program tunes cAMP signaling to direct the neuron-specific assembly and placement of electrical synapses in the C. elegans motor circuit. We use live-cell imaging to visualize electrical synapses in vivo and an optogenetic assay to confirm that they are functional. In ventral A class (VA) motor neurons, the UNC-4 transcription factor blocks expression of cAMP antagonists that promote gap junction miswiring. In unc-4 mutants, VA electrical synapses are established with an alternative synaptic partner and are repositioned from the VA axon to soma. cAMP counters these effects by driving gap junction trafficking into the VA axon for electrical synapse assembly. Thus, our experiments establish that cAMP regulates gap junction trafficking for the biogenesis of functional electrical synapses.

Can Alcohol Intoxication be Excluded as the Cause of Confusion following Head Injury?

Objective: To assess whether there is a breath alcohol level (BrAC) below which confusion in the head injured patient should not be attributed solely to the acute effects of alcohol Method: Based in the Accident and Emergency Ward in Glasgow Royal Infirmary, a prospective observational study was carried out over a five month period. Patients admitted to the ward were recruited for the study if they had a primary diagnosis of head injury. The outcome measures recorded and analysed were sequential 2 hrly BrAC readings (mg/L) and Glasgow Coma Scale findings (Eye opening, motor and verbal responses). The relationship between these was investigated, which revealed additional relevant factors affecting level of consciousness. Results: The breath alcohol analyser was found to be a useful non-invasive, quick and easy to use tool. The results obtained were consistent with the expected pattern of reducing BrAC levels over a 6 hour period. Within this group of patients, a poor correlation was found between each of the three responses of the Glasgow Coma Scale and BrAC readings. For those patients who remained confused, when their BrAC reading was less than 1 mg/L, other causes of a lowered level of consciousness were identified. Conclusion: Confusion in the head injured patient with a BrAC of less than 1 mg/L, should alert one to the likelihood of causes other than alcohol intoxication.

Storage of washed or irradiated red cells in AS-7 improves their in vitro characteristics

BACKGROUND

AS-7 is a new alkaline hypotonic red cell additive solution (AS) shown to improve red cell quality during storage compared with AS-1. We sought to compare red cells stored in AS-7 with those stored in SAGM using RCC that were either untreated, or washed or irradiated on day 14 of storage.

STUDY DESIGN AND METHODS

A pooled and split study design was used to produce seven identical RCC (four in SAGM and three in AS-7). At day 14 following donation, two RCC (one in SAGM and one in AS-7) were gamma irradiated and three RCC (two in SAGM and one in AS-7) were washed and resuspended in either SAGM or AS-7. RCC were sampled for analysis throughout storage and at end of shelf life: day 28 for washed or irradiated and day 35 for untreated RCC.

RESULTS

For untreated, washed or irradiated RCC, those stored in AS-7 had lower haemolysis, red cell microvesicles and supernatant potassium content than RCC in SAGM. In addition, ATP levels and pH were better maintained in AS-7 RCC than in SAGM RCC.

CONCLUSION

These data suggest that the quality of these components may be improved by storage in AS-7 compared with SAGM.

Activation during preparation of therapeutic platelets affects deterioration during storage: a comparative flow cytometric study of different production methods

Three different separation methods, all using centrifugation, are routinely used to prepare therapeutic platelet concentrates from human donor blood. Platelet concentrates derived from platelet-rich plasma (PRP-PC), buffy coat (BC-PC) and apheresis (AP-PC) were investigated at the end of production, and over an 8 d storage period. Change in platelet surface markers were measured by flow cytometry, using fluorescein-conjugated antibodies to fibrinogen, P-selectin (CD62P), GPIIb-IIIa (CD41), GPIb alpha (CD42b) and GPV (CD42d), and fluorescein-conjugated Annexin V was used to measure expression of anionic phospholipid. All concentrates showed some changes during preparation but PRP-PC underwent the greatest changes with significantly higher levels of P-selectin (P<0.001) and bound Annexin V (P=0.001) than AP-PC or BC-PC, and lower levels of GPIb alpha (P=0.002) and GPV (P<0.001). These changes were attributable to component separation rather than venesection. These markers all continued to change on storage with a strong positive correlation between the changes seen during production and those after 5 d storage. PRP-PC continued to show the greatest changes whereas BC-PC showed the least. Fibrinogen was bound to 40-50% of platelets in all preparations and this did not alter significantly on storage whereas total expression of GPIIb-IIIa remained unchanged throughout. There was no evidence that the platelet surface changes were thrombin-mediated and leucocyte depletion of BP-PC by filtration had no effect on the changes. It is proposed that the deterioration of platelet concentrates during storage may be related to activation occurring during preparation. 'Whole blood' flow cytometry using a panel of fluorescein-labelled reagents provides an informative method for evaluating platelet concentrates.

Is appendicitis familial?

A family history of appendicectomy was sought in two groups of children admitted to Llandough Hospital over sixteen months. The study group consisted of 29 children with histologically confirmed acute appendicitis, while the control group consisted of 29 children admitted for reasons unrelated to abdominal pain. A history of appendicectomy was elicited in first-degree relatives--that is, siblings and parents of 20 of the children in the study group and of four of the controls--a statistically significant difference. The results obtained from this study suggest that a familial predisposition to appendicitis exists.

Infrared irradiance from phototherapy units and the effect on osmolality of serum and urine in term infants

The osmolality of urine increased in 10 term infants receiving phototherapy. Phototherapy units made locally were likely to emit more infrared radiation than a unit available commercially, but both types led to falsely increased incubator thermometer readings. Interposing a 6-mm acrylic sheet prevents these effects.

Diagnosis of phaeochromocytoma after ingestion of imipramine

An 11-year-old twin girl was admitted to hospital with a 24-hour history of profuse sweating, tachycardia, and hypertension after a single dose of imipramine. She was subsequently found to have a right adrenal phaeochromocytoma. To our knowledge, this is the first reported case of tumour provocation by imipramine.