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Biomedical subjects

R Backer

Publications and source records attributed to R Backer.

7 recordsLinked to original sources
PubMed1998

Disposition of valproic acid in a case of fatal intoxication.

The case history and toxicological findings of a fatal suicidal valproic acid overdose are presented. Valproic acid concentrations were determined in body tissues and fluids by gas-liquid chromatography (GLC) following both direct extraction and the method of standards addition and quantitative fluorescence polarization immunoassay. The quantitative results obtained by the three procedures were in good agreement. Qualitative identification of valproic acid as its methylated derivative was by ion-trap gas chromatography-mass spectrometry. Toxicological analysis by direct extraction GLC yielded the following valproate concentrations (mg/mL or mg/kg): blood, 1050; bile, 713; brain, 510; heart, 670; kidney, 1580; liver, 985; and vitreous, 516. A total of 15.1 g of valproate was recovered in the stomach contents. These findings far exceed those associated with valproate therapy and are similar to the limited valproate disposition data reported in prior fatal overdoses.

Adult↗
PubMed1997

Fatal ephedrine intoxication.

A 28-year-old white female with a history of two prior suicide attempts was found dead in her home by her common law husband. Autopsy findings were unremarkable except for partially dissolved ephedrine tablets in the stomach contents. Quantitation of ephedrine was by gas chromatography/mass spectrometry (GC/MS) following liquid/liquid extraction from alkaline samples and pentafluoropropionic acid derivatization. Significant toxicological finding included ephedrine; blood, 11 mg/L; liver, 24 mg/kg; kidney, 14 mg/kg; brain, 8.9 mg/kg; and amitriptyline; blood, 0.33 mg/kg; liver 7.8 mg/kg. The ephedrine values found far exceed those associated with therapeutic administration and are consistent with the few reported cases of severe ephedrine intoxication. The cause of death was determined to be fatal ephedrine intoxication and manner of death suicide.

Adult↗
PubMed1997

Fatal fentanyl intoxication following excessive transdermal application.

The case history and toxicological findings of a fatal fentanyl intoxication due to the application of multiple transdermal patches are presented. An 83 year-old white female with terminal cancer was found dead with three 100 mg/h fentanyl patches on her chest. The autopsy and subsequent histological studies revealed extensive areas of gastric carcinoma, a large atrial tumor, ulceration of esophagus, metastasis of peripancreatic lymph nodes and a recent surgical removal of part of the lower lobe of the left lung. Toxicological analysis by GC/MS yielded fentanyl concentrations of blood, 25 ng/mL; brain, 54 ng/g; heart 94 ng/g; kidney 69 ng/g; and liver 104 ng/g. The cause of death was determined to be fentanyl overdose and the manner of death was ruled undetermined as the investigation was unable to conclusively establish whether this was an accidental overdose, a suicide, an assisted suicide, or possible a homicide. This case demonstrates the need for caution in self-administration of transdermal fentanyl patches, in particular, the dangers inherent in the application of multiple patches which can result in the release of potentially toxic or lethal doses.

Administration, Cutaneous↗
PubMedDate not supplied

Blood cyanide levels in mice after administration of amygdalin.

Oral doses of amygdalin and intraperitoneal (i.p.) doses of potassium cyanide (KCN) in the near-lethal range were administered to CD2F1 female mice. Blood cyanide levels were then measured as a function of time. The maximum cyanide level after amygdalin administration was reached at about 11/2 to 2 h and was within the range of values seen after KCN administration. Behaviour of mice correlated with the time of maximum blood cyanide level. Acute distress was observed at times when the cyanide level was highest. There was great variability in the nature and magnitude of the response in individual mice. The ability of the contents of various regions of the gastrointestinal tract and of tumour tissue to release cyanide from amygdalin was assessed. Stomach and upper intestine had little activity while the lower end and the faeces released large amounts. Again, there was a large variation between mice. These results are interpreted to mean that enteric contents are primarily responsible for the release of cyanide from ingested amygdalin. Freshly minced tumour tissue released negligible amounts of cyanide. Ten-fold higher doses of amygdalin administered i.p. produced very small increases in blood cyanide levels and no toxic behaviour. The doses used are comparable to doses which might be ingested by patients receiving oral amygdalin or Laetrile and indicate that oral amygdalin is potentially extremely dangerous.

Administration, Oral↗
PubMedDate not supplied

The imaging of an intraspinal cervical dermoid tumor by MR, CT, and sonography.

Epidermoid and dermoid tumors are uncommon lesions and within the spinal cord are rare. Magnetic resonance imaging has proved sensitive to their detection in the intracranial cavity but the pattern of signal intensities on T1 and T2 weighted images has not been uniform. Utilizing a 0.6 T superconductive magnet an intramedullary cervical dermoid tumor was examined. The correlation between CT demonstrated regions of fat density and the MRI appearance of comparable regions of high intensity signal on T1 weighted images has only rarely been demonstrated in such tumors that have no histologic evidence of adipose tissue. MRI provided all of the information needed pre-operatively.

Adult↗
PubMedDate not supplied

MRI of intradural spinal arteriovenous fistula associated with ischemia and infarction of the cord.

This report presents a patient with an intradural spinal arteriovenous fistula complicated by infarction of the cord. The diagnosis of an arteriovenous malformation was made on the magnetic resonance imaging (MRI) study with the demonstration of intraspinal serpentine areas of low signal intensity (flow voids). The presence of other MRI findings believed to represent spinal cord ischemia included multisegmental swelling of the cord associated with T1 and T2 prolongation and gadolinium enhancement. The location of the malformation, as well as arterial supply and venous drainage, were defined on selective spinal arterial digital subtraction angiography (DSA). Following surgical resection, the clinical condition stabilized, but with poor return of lost function. The repeat MRI 6 months after surgery demonstrated diffuse thoracic cord atrophy.

Arteriovenous Fistula↗