Acute trazodone poisoning: clinical signs and plasma concentrations

A total of 70 patients presenting with suspected acute trazodone poisoning were notified to the Poisons Unit (National Poisons Information Service for England) from August 1980 until March 1983. Detailed follow-up information was obtained on 41 patients, 22 of whom were thought to have ingested trazodone alone. In these latter patients drowsiness (11), ataxia (5), nausea/vomiting (4) and dry mouth (2) were the manifestations of toxicity reported most frequently, only 2 patients became unconscious (grade 2 or 3 coma), and all recovered uneventfully with no more than minimal supportive therapy. The presence of trazodone was confirmed in 8 out of 9 patients from whom specimens (blood and urine) were received. The highest plasma trazodone concentrations (15 and 19 mg/l, respectively) were both associated with only drowsiness and ataxia. However, in 2 further patients moderate plasma trazodone concentrations (4.2 and 8.2 mg/l, respectively) were associated with deep (grade 3-4) coma, although 1 of these latter patients had also ingested ethanol (plasma concentration 3.0 g/l). Although acute trazodone poisoning does not appear to be associated with cardiac arrhythmias or convulsions, these results emphasise that drowsiness and ataxia are commonly encountered, while coma may occur in severe cases. The possible contribution of metabolites of trazodone to toxicity and the potentiating effect of co-ingested drugs or alcohol must be remembered.

Isolation of cell lines from differentiating embryonal carcinoma cultures

We report the isolation of six cell lines (designated EB cell lines) from cultures of the hypoxanthine guanine phosphoribosyl transferase-deficient (HGPRT-) feeder-dependent embryonal carcinoma cell line PSA4TG12 which have undergone in vitro differentiation, and of clonal derivatives of these lines. Whereas some lines possess quasi-diploid karyotypes similar to that of PSA4TG12, others are markedly aneuploid. Cell line EB26/1 and its clonal derivatives undergo adipogenesis in cultures maintained at confluence; in tumours formed by injection into syngeneic mice they produce muscle-like cells, cartilage and bone in addition to adipose cells. We therefore propose that EB26/1 and its clones are aneuploid derivatives of an uncommitted mesodermal cell. Cell line EB28/5 forms tumours with a histological appearance resembling that of yolk sac carcinoma but does not express biochemical markers characteristic of visceral or parietal endoderm. Cell line EB28/10n has a myoblast-like culture morphology and in tumours is capable of producing muscle-like cells, cartilage and bone. A high specific activity of alkaline phosphatase is present is two of five EB cell lines assayed, and plasminogen activator activity is present in all five. Since the EB cell lines represent populations of cells each expressing a particular subset of the genetic information present in a common ancestral genome, they will be invaluable for studying the developmental regulation of gene expression.

A modified life-table analysis system for cohort studies

A person-years at risk life-table analysis system of computer programs has been developed by the National Institute for Occupational Safety and Health (NIOSH) and is available with detailed documentation. The system was specifically designed to analyze occupational cohort mortality data. These programs require more computer core space and processing time than other available life-table programs. However, the NIOSH programs are advantageous because they include the following: (1) input data editing and modification, (2) mortality rates for 89 cause-of-death categories, (3) assignment of cumulative doses to specific person-years based on either personal or area exposure data, and (4) simultaneous examination of observed and expected deaths by duration of employment (or dose), latency, age, and calendar time.

Death due to overdose of nefopam

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The effect of cholesterol on measured interaction and compressibility of dipalmitoylphosphatidylcholine bilayers

We have examined the phase diagram of dipalmitoylphosphatidylcholine (DPPC)--cholesterol-water mixtures at low cholesterol content, and report phase separation between 3 and 10 mol% cholesterol. The two lamellar phases at equilibrium in this region appear to be pure DPPC and 11 mol% cholesterol in DPPC. For these two lamellar phases, which are made up of alternating layers of water and bimolecular lipid leaflets, we have measured the forces of interaction between leaflets and the lateral pressure and compressibility of the leaflets. Both bilayers experience a strong repulsive force when forced together only a few ångströms (1 A = 0.1 nm) closer than their maximum separation in excess water. However, the presence of 11 mol% cholesterol causes the bilayers to move apart of 35-A separation from the 19-A characteristic of pure DPPC in excess water. This swelling may result from a decrease in van der Waals attraction between bilayers or from an increase in bilayer repulsion. Differences in bilayer interaction can be a cause for phase separation. More importantly these differences can cause changes in the composition of regions of membranes approaching contact. At 11 mol%, cholesterol substantially increases the lateral compressibility of DPPC bilayers leading to higher lateral density fluctuations and potentially higher bilayer permeability.

Pharmacokinetics of oral disopyramide phosphate in patients with renal impairment

1 The pharmacokinetics of disopyramide were studied after the oral administration of a 300 mg dose to 11 patients with stable chronic renal impairment (creatinine clearance 2-53 ml min-1). 2 Absorption half-life and volume of distribution were similar to those seen in normal subjects. 3 Mean plasma elimination half-life in these patients was 12.7 h, which is substantially greater than that reported for normal subjects. Elimination half-life tended to increase as creatinine clearance fell, and renal clearance of disopyramide correlated significantly (r=0.814; P < 0.001) with creatinine clearance. 4 From these results, we have calculated that patients with renal impairment should be started on a dose of disopyramide 1.5 mg kg-1 thrice daily and the regimen subsequently altered according to plasma concentrations of the drug. However, further studies are needed to define the handling of the metabolites of disopyramide.

Drug recovery following buccal absorption of propranolol

1 Buccal absorption of propranolol in two volunteers was followed by repeated rinsing of the mouth with buffer solutions for twelve 2 min periods. Values for absorption, recovery and asymptotic recovery were calculated. 2 Large amounts of propranolol were recoverable from the buccal mucosa; recovery was biexponential and the amount recovered depended on the time allowed for absorption and on the pH of buffers used for recovery. 3 In the case of the drug studied, the buccal absorption test was not an adequate model of passive drug transfer through lipid membranes, and more clearly reflected partitioning into the buccal mucosa. 4 It does not follow from disappearance of drug from the buccal cavity that it has entered the circulation. Unabsorbed drug clearly cannot enter the circulation, but other conclusions about systemic absorption cannot be drawn with certainty from the buccal absorption model. 5 Partitioning back into the saliva after absorption also needs to be taken into account for a true model of systemic absorption of orally administered drugs, and a revised schematic representation of the kinetics of oral drug absorption is presented.

A diagnostic sign in states of apparent unconsciousness

Deviation of the eyes towards the ground with the patient lying on each side is proposed as a diagnostic sign in psychogenically mediated states resembling coma or epilepsy. Six cases are described in which the sign was elicited.

Relatively greater increase of oxytocin than vasopressin in the supraoptic nucleus of rats after hypophysectomy

The vasopressor and milk ejection activities were estimated in the supraoptic region of the hypothalamus of rats which had been hypophysectomized 30 min, 4 and 8 days earlier. Both pressor and milk ejection activities were significantly greater 4 days after hypophysectomy than those in sham-operated control rats. Eight days after hypophysectomy, pressor activity decreased below control values but milk ejection activity was still significantly raised. Increased biological activity after hypophysectomy is thus associated with the previously observed increase in neurosecretory material within the supraoptic nucleus so these results provide additional evidence that neurosecretory material represents stored hormone. Milk ejection activity increased relatively more than pressor activity which supports the suggestion that the final stage in the formation of neurohypophysial hormones occurs as they pass from the hypothalamus to the neural lobe. If this final maturation normally occurs more slowly for oxytocin than for vasopressin, the obstruction to the flow of hormones down the neural stalk caused by hypophysectomy would result in a greater increase in milk ejection than pressor activity.