Robert Askenasi

A new rapid method for measuring hydroxylsine and its glycosides in hydrolysates and physiological fluids

Abstract New conditions are described for the measurement of hydroxylysine and its glycosides (Glc-Gal-Hyl and Gal-Hyl) by ion-exchange chromatography in protein hydrolysates of basement membrane and in urine. Elution was carried out on Beckman resin M72 (bed height 55.5 cm) with 0.35 M (with respect to sodium) sodium citrate buffer at pH 5.28, at a flow rate of 50 ml/h at 64°C. The urinary excretions of Glc-Gal-Hyl, Gal-Hyl and hydroxylysine are 16.4, 10.9 and 8.6 μmoles/g creatinine, respectively. The Glc-Gal-Hyl/Gal-Hyl ratio is 1.49. This method gives results in agreement with data already published by other authors and the same conditions can be used for the analysis of hydrolysates and physiological fluids on a regular amino acid analyzer in a quick and simple way.

Flumazenil in mixed benzodiazepine/tricyclic antidepressant overdose: A placebo-controlled study in the dog☆

This study evaluates the cardiac and neurologic risks associated with the antagonization of the benzodiazepine component of mixed drug overdoses, when cyclic antidepressants are also implicated. Twenty-four mongrel dogs were anesthetized and ventilated. Electroencephalogram, electrocardiogram, and tidal carbon dioxide and arterial pressure were continuously recorded. Amitriptyline (1 mg/kg/min) associated with midazolam (1 mg/kg + 1 mg/kg/h) was infused in 12 of the dogs. Midazolam was replaced by saline in the other 12. Drug administration was continued until signs of cardiotoxicity (QRS prolongation greater than 120 milliseconds or sustained arrhythmias) occurred. At that moment, midazolam effects were suddenly reversed by administration of flumazenil 0.2 mg/kg in six dogs out of each group. Placebo was administered in the others. Reactions were observed for the next 120 minutes. Midazolam-induced sedation efficiently protects (P less than .02) against seizures due to amitriptyline toxicity. This protective effect is counteracted by flumazenil. Midazolam has limited influence on the cardiac toxic effects of amitriptyline. The bolus of flumazenil is, however, associated with a significant worsening of electrocardiogram disturbances, and two sudden deaths were recorded. The mechanism of this effect remains unclear, as it could be unrelated to the antagonization of midazolam sedation. Given the problem of extrapolating animal data to humans, these results suggest that bolus administration of high doses of flumazenil in mixed intoxication implicating benzodiazepine and cyclic antidepressants has the potential to precipitate convulsions and/or arrhythmias. A slowly titrated administration of the antidote, as usually recommended, could prevent these effects.

Zolpidem Intoxication Mimicking Narcotic Overdose: Response to Flumazenil

Zolpidem is a recently introduced sleep-inducer which is thought to act on the central-type benzodiazepine receptors. This observation is the first report of drug poisoning with this compound. The toxic response was characterized by the development of a profound but short-lasting coma, associated with pin-point pupils and respiratory depression, as observed in a narcotic overdose. These clinical signs were not influenced by the administration of naloxone, but responded dramatically to flumazenil. Some analytical data on zolpidem toxicokinetics are presented.

Specific treatment of benzodiazepine overdose

Intentional benzodiazepine (BZD) overdose is usually a benign condition frequently encountered in the emergency department of hospital. Twenty-one patients, who were suspected of BZD overdose, were treated with the antagonist of the central type BZD-receptors Ro 15-1788. Samples for toxicological analysis were taken before and after treatment. The patients were divided into three groups. In the first group (pure BZD overdose, n = 9), rapid and complete awakening was observed in all the patients (9/9) with 3.5 ± 1.5 mg Ro 15-1788. In the second group of patients with multiple drugs poisoning (including BZD, n = 6), CNS depression improved in all the patients despite incomplete awakening. In the last group (n = 6), where no BZD were detected in toxicological samples, none of the comatous patients improved significantly during Ro 15-1788 administration, except one patient with pure ethanol intoxication. No undesirable effects are reported, except mild transitory withdrawal syndrome in three cases following rapid injection. This study supports the introduction of Ro 15-1788 as a useful antidote in the diagnosis and the treatment of drug-induced coma.

Urinary excretion of free hydroxylysine, peptide-bound hydroxylysine and hydroxylysyl glycosides in physiological conditions

The amount of urinary hydroxylysine is an index of collagen metabolism. Of the total hydroxylysine measured in normal urine 80 percent is associated with sugars in two glycosidic compounds, glucosyl-galactosyl-hydroxylysine and galactosyl-hydroxylysine, ten percent is free and unglycosylated and the remainder is bound to urinary peptides. The excretion of hydroxylysyl glycosides follow the same physiological variations as urinary hydroxyproline, but it is not influenced by a collagen-free diet. The urinary excretion of hydroxylysyl glycosides, free hydroxylysine and peptide-bound hydroxylysine increases from 6 months of age to puberty. When corrected for urinary creatinine excretion, the largest amounts are found before one year of age. The glucosyl-galactosyl-hydroxylysine/galactosyl-hydroxylysine ratio is lower in the urine of children. After correction of the values to either the body surface area or to the creatinine excretion, no significant differences can be found between the sexes. The different forms of hydroxylysine are discussed.

Activated Charcoal in Tricyclic Antidepressant Poisoning

Tricyclic antidepressants (TCA) bind to activated charcoal both in vitro and in vivo in healthy volunteers after a therapeutic dose of TCA. These findings provide a basis for the routine use of activated charcoal in TCA poisoning. The object of this study was to examine the effect of a single dose of 20 g of activated charcoal in overdose patients. Ninety-one patients from four centres with suspected TCA overdose were entered into a randomized study. Gastric lavage was performed on all patients. Thirty-four received 20 g of activated charcoal and 43 served as controls. Fourteen patients were excluded. Plasma drug concentrations were taken on admission and at 1, 2, 4, 8 and 24 h. The incidence of toxic symptoms was registered during 24 h. There was no significant difference in the area under the plasma drug concentration versus time curve, the peak plasma concentrations or plasma half-lives between the two groups. Toxic symptoms were more frequent in the non-treated groups although this difference was not statistically significant. In patients with TCA overdose initially treated with gastric lavage, a single dose of 20 g of activated charcoal had no effect on the systemic absorption or elimination of TCA.

Ischemic pancreatitis and hepatitis secondary to ergotamine poisoning

Acute ergotamine intoxication in a 29-year-old man was complicated by peripheral ischemia, pancreatitis, and hepatitis. The patient was treated with sodium nitroprusside infusion. Complications and treatment of ergotamine poisoning are discussed.

Efficacy of flumazenil in acute alcohol intoxication: double blind placebo-controlled evaluation.

Flumazenil acts as an antidote for pharmacological and toxic effects due to benzodiazepines. Several isolated observations and short uncontrolled series have also suggested a possible effect against the impairement of consciousness induced by pure alcohol intoxication. Patients admitted in the emergency department with coma related to acute alcohol (ALC) or pure benzodiazepine (BZD) intoxication were randomized and treated blindly with either placebo or 1 mg flumazenil. A modified Glasgow score was used to observe the evolution of consciousness. In the 18 ALC patients, 1 mg flumazenil was not more effective than placebo, whereas it appeared to be very active in the BZD group. However, an open administration of higher doses of flumazenil (2-5 mg) in 11 ALC patients, whose condition had not initially improved, was followed by clear improvement of consciousness in five of them. Flumazenil, administered at a dose usually active against BZD sedation, does not improve CNS depression induced by ALC intoxication. Higher doses could be more effective in some patients, but it should also be verified in a placebo-controlled trial.

The origin of urinary hydroxylysyl glycosides in Paget's disease of bone and in primary hyperparathyroidism

The urinary excretion of glucosyl-galactosyl-hydroxylysine and of galactosyl-hydroxylysine were studied in Pagets disease of bone and in primary hyperparathyroidism. Both metabolites were increased in these diseases.Although glucosyl-galactosyl-hydroxylysine is not abundant in bone collagen, it is possible that a part of it originates from calcified tissue.

Naloxone and Alcohol Intoxication in the Dog

1 The effects of naloxone upon ethanol-induced coma have been investigated in dogs. In a double blind study, 15 mongrel dogs received ethanol i.v. (4 g/kg) followed by a single dose of naloxone (12 ?g/kg). 2 Naloxone failed to affect either the duration of respiratory arrest or the time to recovery of motor coordination. In similar animals treated with the narcotic analgesic, fentanyl, naloxone induced a dramatic and complete reversal of the narcotic effects within 30 seconds. 3 It is concluded that, if naloxone has any effect in alcoholic coma, it is not comparable with its dramatic action in narcotic coma.