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Biomedical subjects

J Lundberg

Publications and source records attributed to J Lundberg.

66 records · Page 4Linked to original sources

Vagal influence on serotonin concentration in enterochromaffin cells in the cat.

The intracellular concentrations of 5-HT in enterochromaffin cells of the jejunum, midgut and ileum of the cat have been estimated by a cytofluorimetric method before and after various periods of peripheral vagal nerve stimulation. The fluorescence intensities in randomized cell samples were measured photometrically after a standard illumination time before and after nerve stimulation. A significant decrease in 5-HT concentration in the enterochromaffin cells all through the small intestine could be demonstrated, which is in support of the hypothesis of a neurogenic release of 5-HT from enterochromaffin cells, possibly caused by vagal adrenergic fibres.

Animals↗

A possible vagal adrenergic release of serotonin from enterochromaffin cells in the cat.

The intracellular concentrations of serotonin (5-HT) in enterochromaffin cells (EC) in the cat small intestine have been studied by a cytofluorimetric method before and after long-lasting efferent vagal nerve stimulation in the neck. Such stimulation induces a decrease of 5-HT in EC of the gut as observed previously. Pretreatment with atropine could not block this decrease, suggesting a noncholinergic mechanism. Pretreatment with a beta-blocking agent, propranolol, or bilateral removal of the superior cervical ganglia could, however, block this 5-HT decrease. Pretreatment with an alpha-blocking agent, phenoxybenzamine, caused an increase in the 5-HT content of EC both with and without nerve stimulation; the reason for this is obscure. The results indicate, that vagal nerve stimulation induces a neurogenic 5-HT release from EC in the gut, and that adrenergic fibres, originating in the superior cervical ganglia, mediate this release probably via a beta-receptor mechanism. Whether or not an alpha-receptor mechanism is also involved cannot be judged at present.

Animals↗

Catecholamine-containing nerve fibres in the human abdominal vagus.

The vagal nerve of man has been investigated for the presence of adrenergic nerve fibres using the histochemical fluorescence method of Hillarp and Falck. Following 30-60 min of nerve ligation during surgical operations, the right anterior main trunk (subdiafragmatic level) from one patient, and the anterior nerve of Latarget of 5 patients were found to contain unmyelinated nerve fibres with accumulations of green fluorescent material representing a catecholamine. The observations indicate the presence of adrenergic nerve fibres running caudally in the human vagal nerve, in accordance with similar findings in other mammals, e.g. cats and dogs.

Abdomen↗

Staphylococcus aureus bacteremia: the cost-effectiveness of long-term therapy associated with infectious diseases consultation.

OBJECTIVE: To investigate the cost-effectiveness of long-term therapy for Staphylococcus aureus bacteremia and to determine if an infectious diseases consultation affected the duration of therapy. METHODS: A decision analysis was performed based on data from the literature. To determine if consultation was related to therapy duration, a retrospective cohort study was performed using tightly matched pairs. RESULTS: The excess cost per life saved by long-term antibiotics was $500,000. The excess cost per life-year saved was $18,000. Nine pairs were matched. Patients who received consultation were more likely to receive long-term therapy than controls (median 41 days vs 15 days for controls, P = .04). CONCLUSIONS: The estimated cost per life-year saved by long-term therapy was similar to other accepted medical interventions. Infectious diseases consultation can encourage prolonged duration of antibiotic therapy for S aureus bacteremia.

Anti-Bacterial Agents↗

Auditory function after spinal anesthesia.

OBJECTIVE: To determine the effect of spinal anesthesia using 26-gauge needles on hearing. METHODS: Eighteen male patients undergoing transurethral resection of the prostate (TURP) or other transurethral procedures under spinal or epidural anesthesia were studied prospectively to reveal possible auditory side effects of dural puncture or absorption of irrigation fluid to the blood stream. Measurement of auditory function by pure tone, Bekesy and speech audiometry, and measurement of serum concentrations of sodium, potassium, urea, and glucose were performed preoperatively and postoperatively. Clinical examination of cranial nerve functions was performed postoperatively. RESULTS: No mean change in hearing ability was seen in any group. One patient had severe, transient, low-frequency hearing loss with simultaneous severe postdural puncture headache. A statistically significant postoperative fall in serum osmolarity was noted in the epidural TURP group. CONCLUSION: Transient, severe hearing loss may still occur after spinal anesthesia using a 26-gauge needle. Minor hearing loss does not seem to be a problem with this needle size.

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