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Biomedical subjects

M Tenenbein

Publications and source records attributed to M Tenenbein.

At least 19 recordsLinked to original sources
PubMed1995

Methanol half-life during ethanol administration: implications for management of methanol poisoning.

STUDY OBJECTIVE: To determine the half-life of methanol in methanol-poisoned patients who are treated with ethanol but not with hemodialysis. DESIGN: Case series. SETTING: University Hospital, University of Manitoba. PARTICIPANTS: Three methanol-poisoned patients treated with ethanol but not with hemodialysis and three similar patients identified by a literature review. RESULTS: Plots of terminal concentration versus time data were inconsistent with zero-order kinetics and were adequately explained by an apparent first-order process. The median half-life of methanol in these patients was 43.1 hours, with a range of 30.3 to 52.0 hours. CONCLUSION: Because of the significantly increased risk of toxicity and complications during ethanol monotherapy, we suggest that hemodialysis be considered for methanol-poisoned patients who are treated with ethanol infusion.

Adult↗
PubMed1995

The abstract and the academic clinician.

The abstract is an essential element of all phases of the research process--submission of proposals for funding, presentation at scientific meetings, and ultimately, publication. Thus, the writing of effective abstracts is an important skill for the academic clinician. Like all skills, it requires significant time and effort for its acquisitions and practice for its maintenance. The structured abstract provides guidance for both format and content, and is an important innovation.

Abstracting and Indexing↗
PubMed1995

Does iron deficiency raise the seizure threshold?

To determine the effect of iron status on the seizure threshold, measures of iron sufficiency were prospectively evaluated in 51 children presenting to a pediatric emergency department with a febrile illness with (26) or without (25) an associated febrile seizure. A higher proportion of children from the febrile seizure group had a family history of mental retardation (5/26 versus 0/25, P = .02) or of previous febrile seizures (10/26 versus 2/23, P = .01). The two groups were otherwise comparable for age, sex, race, family history of afebrile seizures, temperature at presentation, white blood cell count, differential, and vitamin and antibiotic use. Patients with febrile seizures were less frequently iron deficient as defined by a free erythrocyte protoporphyrin level above 0.80 ng/L (2/23 versus 10/25, P < .01), hemoglobin concentration less than 110 g/L (1/26 versus 6/25, P < .03), hematocrit less than 0.30 L/L (0/22 versus 4/25, P < .02), mean corpuscular hemoglobin less than 20 pg (0/25 versus 3/24, P < .04), mean corpuscular volume less than 65 fL (0/26 versus 4/24, P < .02), and platelet count higher than 550 x 10(9)/L (0/26 versus 3/25, P < .04). This association was even stronger when adjusted for differences in family history. None of the patients in the febrile seizure group was being treated for iron deficiency at presentation, whereas three of 25 controls used an iron supplement (P < .04). Iron deficiency may protect against the development of febrile seizures.

Anemia, Iron-Deficiency↗
PubMed1995

Survival after a severe iron poisoning treated with intermittent infusions of deferoxamine.

Iron poisoning is the most common cause of overdose mortality in children under six years of age and there are no reports of survival with iron levels > 2687 mumol/L (> 15,000 micrograms/dL). A 22-month-old male was brought to the emergency department by his parents after ingesting an estimated 50 ferrous sulfate tablets (60 mg elemental iron/tablet) several hours earlier. Despite spontaneous emesis and gastric lavage his condition deteriorated and he was found to have a serum iron of 2992 mumol/L (16,706 micrograms/dL). During the first four days in the intensive care unit, he developed coma, metabolic acidosis, hypovolemic and cardiogenic shock, liver failure, coagulopathy and adult respiratory distress syndrome. He was treated with a unique deferoxamine dosage schedule (25 mg/kg/h for 12 h/d x 3 d), mechanical ventilation, Swan-Ganz catheter monitoring, dopamine/nitroprusside therapy, blood product, bicarbonate, electrolyte and volume replacement. After a prolonged hospital course complicated primarily by gastric outlet obstruction he was dismissed on full oral feedings, gaining weight, and neurologically intact. Swan-Ganz catheter monitoring guided the management of this patient's shock, iron-induced cardiac failure, and deferoxamine mesylate induced adult respiratory distress syndrome. Further experience and research is required to determine the most appropriate deferoxamine mesylate dosing schedule and our experience expands the range for possible survival after massive iron overdose.

Deferoxamine↗
PubMed1993

Intravenous pentazocine and methylphenidate abuse during pregnancy. Maternal lifestyle and infant outcome.

OBJECTIVE: To report the effects of intravenous abuse of pentazocine hydrochloride and methylphenidate hydrochloride during pregnancy. DESIGN: Retrospective chart review. PATIENTS: All pregnant women and their offspring, whose hospital records indicated prenatal abuse of pentazocine and methylphenidate during the 2-year study period. RESULTS: The median for maternal age was 22 years and the median number of prenatal visits was two. Twenty mothers had sexually transmitted diseases, 27 abused alcohol, 10 abused other drugs, and all smoked cigarettes. Eight infants were premature, and 12 were growth retarded. Four infants had congenital anomalies: fetal alcohol syndrome (two [twins]), structural heart defect (one), and polydactyly (one). Eleven infants were treated for neonatal abstinence syndrome. Seventeen infants had normal developmental quotients, and four had low-normal developmental quotients. CONCLUSIONS: Intrauterine exposure to pentazocine and methylphenidate appears to be associated with prematurity, growth retardation, and signs of neonatal withdrawal, but not with any particular teratogenic anomaly or severe developmental delay.

Adolescent↗
PubMed1993

Pulmonary toxicity of deferoxamine in iron-poisoned mice.

Previously we have shown that a group of patients treated for iron overdose with prolonged deferoxamine (DFO) infusion died of adult respiratory distress syndrome (ARDS). We now describe a model to investigate the mechanism of this pulmonary toxicity. Mice treated with 1 oral dose of iron (Fe) and then multiple injections of DFO, or with the chelated product ferrioxamine alone, did not develop lung lesions, even at doses which induced mortality. To potentiate any possible free radical reaction, other groups of mice were treated similarly while exposed to 75-80% O2 over a 4-day period. Ten of 12 mice receiving 0.75 mg Fe and then DFO (10 mg, 4 times/day for 4 days) with hyperoxia died suddenly. At autopsy the lungs were dark red and solid; sections showed hyaline membranes and alveolar exudates of edema, fibrin, and PMN. Electron microscopy showed massive destruction of the alveolar epithelium; using cerium chloride, a free radical reaction product was demonstrated at the alveolar surface. Lung lavage fluid contained 10-12 x normal levels of protein when the Fe-DFO-O2 group was compared to air or O2 controls. Mice receiving DFO or Fe, plus O2, showed only slight injury and a small increase in alveolar protein. The results indicate that Fe plus DFO generates free radicals in the lung, a reaction potentiated by hyperoxia to produce an ARDS-like picture. This suggests that the pulmonary toxicity of DFO in iron-poisoned patients is due to its prooxidant activity resulting in free radical destruction of the airblood barrier.

Animals↗
PubMed1993

Sensory evoked potentials in inhalant (volatile solvent) abuse.

A study was made to determine whether children with a significant history of inhalant abuse but who lack clinical evidence of neurological abnormality have abnormal visual, auditory or somatosensory evoked potentials. Visual, auditory and somatosensory evoked potential studies were obtained from 15 such children aged 9-17 years. Eight of the children had abnormal visual or auditory evoked potentials. Somatosensory evoked potentials were normal in all. It was concluded that evoked potentials may serve as an objective marker of early neurological damage in children who abuse inhalants and demonstrate potential usefulness for counselling and intervention.

Administration, Inhalation↗
PubMed1992

Pulmonary toxic effects of continuous desferrioxamine administration in acute iron poisoning.

The drug of choice for the treatment of iron poisoning is desferrioxamine, though the best route of administration, dose, and duration of treatment are unclear. We report fatal lung injury in four patients who were treated with continuous intravenous infusions. The patients, aged 19-26 years, had received desferrioxamine infusions of 15 mg/kg per h for 65-92 h. Respiratory distress developed after 32-72 h. The patients met clinical, physiological, and necropsy criteria for the diagnosis of adult respiratory distress syndrome (ARDS); none had any of the known risk factors for the development of this disorder. We reviewed the records of forty-three iron-poisoned patients treated with desferrioxamine infusions. No patient treated for less than 24 h had pulmonary complications; however, of the fourteen treated for longer than 24 h, four were the patients with ARDS and four others had pulmonary oedema of other causes. We suggest that the pulmonary complications are caused by continuous infusion of desferrioxamine and that the ARDS in these patient was a consequence of free-radical generation. We recommend that desferrioxamine infusion should not be administered for longer than 24 h.

Acute Disease↗
PubMed1992

Multiple-dose charcoal and whole-bowel irrigation do not increase clearance of absorbed salicylate.

BACKGROUND: This study assesses whether oral multiple-dose charcoal therapy (MDC) or whole-bowel irrigation (WBI) enhances the excretion of previously absorbed salicylate. METHODS: A controlled, randomized, three-limbed crossover protocol was used in nine humans who ingested aspirin. Salicylate levels were measured in serial serum specimens and 32-hour urine collections and kinetic parameters were calculated. RESULTS: There were no differences among the control (CTL), MDC, or WBI groups for area under the serum concentration vs time curve (CTL, 2320 +/- 501 mg/L.h MDC, 2040 +/- 454 mg/L.h; WBI, 2093 +/- 418 mg/L.h) or for urinary salicylates (CTL, 54.9% +/- 9.4%; MDC, 50.9% +/- 8.0%, WBI, 52.4% +/- 13.7% of ingested dose). CONCLUSIONS: Our data do not support the use of either MDC or WBI to enhance the excretion of previously absorbed salicylate in poisoned patients. In patients with drug overdoses, a clear rectal effluent remains as the endpoint for WBI.

Administration, Oral↗
PubMed1991

The total iron-binding capacity in iron poisoning. Is it useful?

Traditionally, a serum iron concentration in excess of the total iron-binding capacity (TIBC) is considered as an indication for deferoxamine therapy in acute iron poisoning. We observed a reversible elevation of the TIBC in patients with iron poisoning that coincided with their acute hyperferremia and have hypothesized that this is a laboratory aberration. We tested this hypothesis in vitro and found that the addition of iron to test serum samples produced a related increase in the TIBC, and alteration of the assay by providing additional adsorbent prevented this occurrence. We also evaluated the reproducibility of the TIBC as performed by 500 laboratories on 10 different reference samples. The mean coefficient of variation was 16%, which was unsatisfactory. We concluded that the TIBC should not be used in the decision for the initiation of deferoxamine therapy in acute iron poisoning. Furthermore, high TIBC values that are occasionally seen in patients with iron poisoning should not be considered as providing a protective effect.

Binding Sites↗
PubMed1991

Multiple doses of activated charcoal: time for reappraisal?

Multiple-dose charcoal therapy has become a popular treatment for many overdoses. It is generally perceived as a simple, inexpensive, effective, and safe procedure that decreases morbidity and mortality by enhancing drug excretion. However, increased drug clearance has been shown definitively for only a few drugs, and improved outcome has not been demonstrated conclusively for any overdose. Recently, there have been several reports of complications due to this intervention. The role of this pharmacologic curiosity in the management of the acutely poisoned patient requires reassessment.

Charcoal↗