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Biomedical subjects

Y Bentur

Publications and source records attributed to Y Bentur.

At least 37 records · Page 2Linked to original sources
PubMed1993

The role of calcium gluconate in the treatment of hydrofluoric acid eye burn.

Hydrofluoric acid is used for different purposes in industry and in the home as a rust remover. Most exposures are accidental and may result in severe superficial and deep tissue injury as well as systemic toxicity. There is uncertainty regarding the optimal treatment of hydrofluoric acid eye injury. A patient in whom a solution of 49% hydrofluoric acid induced a large corneal erosion is described. Repeated instillation of 1% calcium gluconate eye drops combined with the conventional treatment of acid eye burns resulted in a complete and quick recovery.

Adult↗
PubMed1993

Pharmacokinetics of obidoxime in organophosphate poisoning associated with renal failure.

Obidoxime is an oxime used in several countries as an antidote in organophosphate intoxication. Its pharmacokinetics were studied in a 20 year-old female with severe and complicated methamidophos intoxication. Obidoxime elimination half life was 6.9 h, volume of distribution 0.845 L/kg, total body clearance 85.4 mL/min, and renal clearance 69 mL/min (creatinine clearance 54 mL/min). Eighty percent of the dose was excreted in the urine over 5 h. Possible reasons for the different pharmacokinetic values as compared with values previously reported in healthy volunteers are discussed. Obidoxime dose should be adjusted according to renal function. More studies are needed to establish the therapeutic window of obidoxime in patients with organophosphate intoxication.

Acute Kidney Injury↗
PubMed1993

Comparison of the pharmacokinetics of 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in healthy volunteers, with and without co-administration of ferrous sulfate, to thalassemia patients.

Given the mortality and morbidity associated with acute iron intoxication, effective iron chelation which is easily administered in an emergency situation would be ideal. The pharmacokinetics of L1 were examined in 5 healthy adult male volunteers to assess its potential for use in acute iron overload. Ferrous sulfate (600 mg), L1 (900 mg), and ferrous sulfate and L1 were administered on three separate days, each one week apart. On each test day, blood samples were collected at regular intervals for the measurement of plasma L1 and total iron. Pharmacokinetic values were calculated. The data were also compared to that obtained in 10 patients with beta-thalassemia and chronic iron overload. In the normal volunteers, a 20% decrease in the area under the concentration time curve of plasma iron and of plasma L1 was demonstrated when they were co-administered. There was no change in urinary iron excretion when L1 was given with iron (p = 0.414). The elimination half-life of L1 in the thalassemia patients (137.65 +/- 48.65 min) was significantly longer than that in the healthy volunteers (77.56 +/- 13.0) (p = 0.0047) due to larger apparent volume of distribution. In all of the iron-overloaded individuals L1 resulted in increased urinary iron excretion. None of the other pharmacokinetic variables compared were significantly different between these two groups. These studies indicate that at levels below saturation, transferrin does not allow L1 to remove absorbed iron in healthy volunteers, whereas in thalassemia patients, who are beyond saturation of their iron binding capacity, the drug binds iron and promotes its excretion.

Adolescent↗
PubMed1992

Atropine poisoning in children during the Persian Gulf crisis. A national survey in Israel.

OBJECTIVE: To evaluate the effects of high doses of atropine in children accidentally injected with automatic atropine injectors. These were distributed in Israel during the Persian Gulf Crisis as an antidote for chemical warfare agents. DESIGN AND SETTING: A national survey in pediatric emergency departments in Israel, involving 22 medical centers, with prospective data collection in 14 centers. PATIENTS: Children (n = 268) presenting to emergency departments following misuse of automatic atropine injectors. MAIN OUTCOME MEASURES: Documentation of atropine dose and clinical manifestations; determination of a clinical severity score and its correlation with atropine dose; measurements of serum atropine levels in six patients. RESULTS: Over a period of 4 months, 268 cases were reported, of which 240 were clinically evaluated. The most common site of injection (75%) was the finger or palm. Doses were up to 17-fold higher than standard doses for age. In 116 children (48%), systemic effects of atropine were observed, and 20 (8%) had severe atropinization. Seizures and life-threatening arrhythmias were not reported, and there were no fatalities. The severity of atropinization was correlated with the dose following a classic nonlinear, dose-response relationship. Serum atropine levels (6.2 to 61.0 ng/mL) were much higher than those observed after administration of therapeutic doses. CONCLUSIONS: The high incidence of injection in the hand implies accidental use of automatic atropine injectors among children. The lack of mortality or life-threatening complications from injection of large doses of atropine attests to its relative safety in children. The low risk from atropine injections weighed against expected benefit as a lifesaving antidote justifies the distribution of personal atropine injectors to children at risk of organophosphorus nerve agent attack.

Accidents↗
PubMed1992

[Hyperbaric oxygen for neuropsychiatric sequelae of carbon monoxide poisoning].

A broad range of neuropsychiatric abnormalities, including dementia, psychosis, and parkinsonism, as well as almost every known neurologic syndrome, can occur following carbon monoxide (CO) poisoning. These symptoms develop 2-40 days (usually 2-3 weeks), after initial exposure. There is an incidence of recurrence of up to 40%. However, in recent years the neuropsychiatric sequelae appear to have been occurring less frequently, perhaps as a direct result of the use of hyperbaric oxygen (HBO) therapy. There is no specific therapy for this complication, but up to 75% recover within 12-18 months. Myers et al. (Ann Emerg Med, 14: 1163, 1985) found HBO to be effective for the neuropsychiatric sequelae. We report a 19-year-old man who developed late psychiatric disturbances despite the use of HBO for acute CO intoxication. The neuropsychiatric symptoms, which developed 3 days after full recovery of consciousness, resolved completely when HBO therapy was reinstituted. 6 months later he was functioning normally with no neuropsychiatric symptoms.

Adult↗
PubMed1992

Obstructive airway disease associated with occupational sodium hydroxide inhalation.

Sodium hydroxide (NaOH) is well known for its corrosive properties and its ability to generate heat on contact with water. The respiratory effects of industrial exposure to NaOH have, however, never been reported. A 63 year old man worked daily for 20 years cleaning large industrial jam containers by boiling lye (NaOH) solution without using respiratory protective equipment. Physical examination, chest x ray film, pulmonary function tests, and arterial blood gases were all compatible with severe obstructive airway disease with significant air trapping. It is probable that this massive and prolonged occupational exposure to the corrosive effect of NaOH mists induced irritation and burns to the respiratory system, eventually leading to severe obstructive airway disease.

Humans↗
PubMed1991

Exposure to ionizing radiation during pregnancy: perception of teratogenic risk and outcome.

We quantified the perception of teratogenic risk in women attending the Motherisk program for counseling about diagnostic radiation in pregnancy (n = 50) and compared it with a control group of women exposed to nonteratogenic drugs and chemicals (n = 48). Before receiving known information about the specific exposure, women exposed to radiation assigned themselves a significantly higher teratogenic risk compared with the control group (25.5 +/- 4.3% versus 15.7 +/- 3.0% for major malformations, P less than 0.01). The post-consultation perception of teratogenic risk did not differ between the two groups. Special consideration and attention should be given when counseling pregnant women exposed to low-dose ionizing radiation, as their misperception of teratogenic risk may lead them to unnecessary termination of their pregnancy.

Abnormalities, Radiation-Induced↗
PubMed1991

The three most common occupational exposures reported by pregnant women: an update.

Many uncertainties exist in regard to counseling women with occupational exposures during pregnancy. This is due to limited knowledge of the reproductive toxicologic effects of industrial agents, lack of safety standards aimed at protecting the fetus, and limitations in assessing the extent of exposure. The approach to this subject taken by the Motherisk Program and a review of the three most common occupational exposures are presented. Epidemiologic studies and measurements of radiation do not suggest a reproductive hazard for video display terminals. Exposure to organic solvents is hard to quantitate, and information is sparse and sometimes contradictory, and therapeutic decisions are difficult to reach. To date there is no convincing evidence that working with organic solvents within safety regulations would harm a fetus, in contradistinction to detrimental fetal effects of solvent abuse. The reproductive risks of lead are well documented, fetal exposure can be assessed, and effective treatment exists, but its effects on the pregnancy have not been fully established. However, new evidence suggests that maternal levels that are much lower than the accepted adult limits may be damaging to the fetus.

Computer Terminals↗
PubMed1991

Tissue plasminogen activator for the treatment of thromboembolism in infants and children.

We report our experience with the use of tissue plasminogen activator to treat 12 infants and children with various thromboembolic states after conventional thrombolytic agents had failed. The dosage range was between 0.1 to 0.5 mg/kg per hour. Complete clot dissolution occurred in seven cases after 2 hours to 3 days of therapy. Partial clot dissolution and clinical improvement were noted in another four patients. Bleeding complications were noted in 6 of the 12 patients and included bruising, oozing from various venipuncture sites, and bleeding; these complications were controlled by clinically available means. In all cases with bleeding the dose rate was in the higher range (0.46 to 0.50 mg/kg per hour). In one patient, restlessness, agitation, and screaming were noted during administration of tissue plasminogen activator and when it was reinstituted. We conclude that tissue plasminogen activator is effective in inducing clot lysis in children. Because the effective dose appears to overlap with those causing bleeding, we recommend that a dose of 0.1 mg/kg per hour be started and increased gradually if clot dissolution does not occur, with close monitoring for bleeding.

Adolescent↗
PubMed1991

Renal handling of cisplatin: interactions with organic anions and cations in the dog.

Cis-diamminedichloroplatinum (II) (cisplatin CDDP) is an extremely potent chemotherapeutic agent. Its efficacy, however, is hindered by the cumulative dose-dependent nephrotoxicity which can lead to permanent renal impairment. The mechanisms of the renal transport of cisplatin are not clear. As a first step towards understanding the renal handling of cisplatin we studied its renal clearance in dogs, as well as the effects of organic anion and cation administration on cisplatin. Our results document net tubular secretion of cisplatin. Both an organic anion (probenecid) and cations (quinidine, cimetidine, ranitidine) significantly decreased renal clearance of free CDDP without affecting GFR.

Animals↗
PubMed1991

The effects of subcutaneous deferoxamine administration on renal function in thalassemia major.

To assess the effects of deferoxamine (DFO) on the kidneys, we studied 27 patients with thalassemia major on chronic subcutaneous (s.c.) DFO therapy. In 41% of the patients glomerular filtration rate (GFR) values were above the normal range. In a previous study similar findings were reported for thalassemia patients who did not receive DFO. The subcutaneous administration of DFO was associated with a clinically significant decrease in GFR in 40% of the patients and in a mild decrease in another 40%. In all cases of severe decreases in GFR, it tended to return to baseline values upon discontinuation of DFO. There was a significant increase in urine volume during DFO therapy. These changes are consistent with our previous observation in humans and dogs receiving high dose i.v. DFO, albeit milder.

Adolescent↗
PubMed1990

Comparison of oral iron chelator L1 and desferrioxamine in iron-loaded patients.

The efficacy of the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) was compared with that of subcutaneous desferrioxamine in 26 patients with transfusional iron overload. Immediately after red-cell transfusion, 20 patients were randomised to receive either desferrioxamine (50 mg/kg daily as a 12 h subcutaneous infusion), or L1 (50 mg/kg daily by mouth). Patients were evaluated during treatment with the other drug after transfusion the next month. Mean (SD) daily urinary iron excretion was lower during L1 than during desferrioxamine (12.3 [6.7] vs 18.2 [15.3] mg/day). In 5 patients the dose of L1 was raised from 50 to 75 mg/kg daily; mean urinary iron excretion rose from 13.8 (7.0) mg/day to 26.7 (17.8) mg/day, comparable with that during desferrioxamine (24.9 [24.3] mg/day). Faecal iron excretion rose slightly over baseline in 6 patients studied during L1 administration (from 8.5 [0.9] mg/day to 12.2 [0.9] mg/day). Pharmacokinetic studies showed an elimination half-life for L1 of 117-237 min. Studies in dogs and in volunteers showed no absorption of the L1-iron complex, excluding a contribution of absorption of intraluminal complexes of L1 and food iron to urinary iron excretion. Further animal toxicity testing is needed before L1 can be studied in a broader group of patients.

Adolescent↗
PubMed1990

Effect of endogenous digoxin-like substances on the interpretation of high concentrations of digoxin in children.

The objective of this study was to assess the effect of endogenous digoxin-like substances on the interpretation of excessive concentrations of digoxin in children. After the development of a high-pressure liquid chromatography (HPLC) method for digoxin in our laboratories, we analyzed sera of children in whom the fluorescence polarization immunoassay identified potentially toxic concentrations of the glycoside (greater than 3 nmol/L; 2.3 ng/ml). Sixteen of them were receiving long-term digoxin therapy, and one had an accidental overdose. The immunoassay yielded significantly higher concentrations (4.1 +/- 1.2 nmol/L; 3.2 +/- 0.9 ng/ml) than the HPLC method (3.3 +/- 1.6 nmol/L; 2.6 +/- 1.2 ng/ml; p less than 0.01). In five cases (30%) these differences were clinically significant because administration of digoxin had been discontinued in the presence of true digoxin concentrations within the therapeutic range and the lack of clinical toxic effects. These data suggest that therapeutic drug monitoring using immunoassays of digoxin may be too inaccurate to detect potential toxic effects, and that much more weight should be focused on clinical monitoring. The HPLC method for assay of digoxin is extremely meticulous and will not become clinically available; therefore the development of better immunoassays should be encouraged.

Adolescent↗
PubMed1990

Comparison of deferoxamine pharmacokinetics between asymptomatic thalassemic children and those exhibiting severe neurotoxicity.

The use of deferoxamine for iron chelation in transfusion-dependent thalassemia major is limited by serious neurotoxicity (hearing and vision loss). We assessed whether interpatient variability in handling deferoxamine and resultant accumulation of the drug may account for the neurotoxicity. We studied steady-state deferoxamine pharmacokinetics during intravenous infusion in two groups of patients--one group exhibited severe manifestations of auditory and visual loss and one group was asymptomatic. The groups were matched for age, sex distribution, weight, treatment period, ferritin levels, and hemoglobin levels. Similarly, doses of deferoxamine at the time of the study were not different. Clearance rates were not different between the symptomatic and asymptomatic patients (39.83 +/- 4.54 versus 30.66 +/- 4.39 ml/min.kg). However, patients who exhibited toxicity received significantly higher daily doses of subcutaneous deferoxamine at the time of diagnosis of neurotoxicity (9.03 +/- 0.96 and 5.58 +/- 0.61 mg/kg.hr, respectively; p less than 0.005). These data suggest that deferoxamine induced neurotoxicity is dose-dependent and cannot be attributed to accumulation of the drug caused by slower clearance rates.

Adolescent↗
PubMed1990

Methodological issues in studying the effect of the new oral chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) on absorption of iron.

Although deferoxamine is currently the drug of choice for iron chelation, there is more and more evidence of its toxicity. As a replacement for deferoxamine, 1,2-dimethyl-3-hydroxypyrid-4-one (L1), a new oral iron chelator, is undergoing clinical studies in thalassemic patients. Iron handling in experimental acute iron intoxication is being studied in a multiphase study. Preliminary results suggest that the L1-iron complex is not absorbed from the gastrointestinal tract. Methodological issues in studying iron chelation in the context of acute iron intoxication are presented.

Administration, Oral↗
PubMed1989

Acute changes in renal function associated with deferoxamine therapy.

In three patients who received intravenous deferoxamine there was a twofold to eightfold increase in plasma creatinine level and a parallel decrease in creatinine clearance that resolved when treatment with the drug was discontinued. In two thalassemic patients, diuresis was evident by urine output exceeding fluid intake. The mechanism was studied in dogs that exhibited an acute and significant decrease in inulin and para-aminohippuric acid clearances induced by intravenous deferoxamine. Saline diuresis could prevent the decrease in the glomerular filtration rate but not the decrease in renal blood flow caused by deferoxamine. Deferoxamine induced an acute increase in the fractional excretion of sodium, potassium, chloride, phosphate, and urate, which may explain the relative diuresis observed in two of the patients. In a subsequent experiment, ferrioxamine induced an increase in the fractional excretion of sodium and chloride but did not affect the glomerular filtration rate and renal blood flow. Our studies suggest that adequate hydration may be needed to preserve renal hemodynamics during intravenous deferoxamine therapy. Repeated measurements of renal function should accompany treatment with this agent.

Adolescent↗