ABSTRACT
Studies were conducted to evaluate the effect of experimental protocol on the ability of benzidine (BZD), dimethylbenzanthracene (DMBA) and mitomycin C (MMC), administered by intraperitoneal injection, to induce micronuclei in polychromatic erythrocytes (PCE) of B6C3F1 mice. Three different treatment/sampling protocols were used, involving from one to three consecutive daily treatments and from three to one, respectively, consecutive daily samplings beginning 24 h after the last injection. DMBA and MMC elicited a significant micronucleus response in all three experimental protocols, while BZD induced a significant response only in the multiple injection protocols. Of the three protocols, the 3-day injection/single sample time protocol offers the greatest efficiency in minimizing the number of animals required in a study, in decreasing the time needed for scoring and in simplifying the statistical analysis. In addition, a comparison of the frequency of micronucleated PCE in peripheral blood and bone marrow following the treatment of mice with either BZD or DMBA suggests that, following a three injection protocol, either tissue can be used with equal efficacy.
Subject(s)
9,10-Dimethyl-1,2-benzanthracene/toxicity , Benzidines/toxicity , Chromosome Aberrations , Micronucleus Tests , Mitomycins/toxicity , 9,10-Dimethyl-1,2-benzanthracene/administration & dosage , Analysis of Variance , Animals , Benzidines/administration & dosage , Bone Marrow/drug effects , Bone Marrow Cells , Erythrocytes/drug effects , Injections, Intraperitoneal , Male , Mice , Mitomycin , Mitomycins/administration & dosage , Regression AnalysisABSTRACT
We report 20 girls who experienced episodes of unconsciousness while standing for hair grooming. The episodes were syncopal in character, electroencephalograms were normal in most cases, and at least 11 of the 20 had definite episodes of syncope in other circumstances. A number of these girls underwent extensive diagnostic testing. We consider this a form of situational or reflex syncope, perhaps related to orthostatic hypotension, the recognition of which may spare unnecessary diagnostic and therapeutic interventions.
Subject(s)
Hair , Hygiene , Posture , Syncope/etiology , Adolescent , Child , Child, Preschool , Female , Humans , Hypotension, Orthostatic/complicationsSubject(s)
Hexachlorophene/poisoning , Peritoneal Dialysis , Child , Evaluation Studies as Topic , Half-Life , Hexachlorophene/analysis , Humans , MaleABSTRACT
We review electroencephalograms taken from 17 patients with severe meningoencephalitis within seven days of onset of CNS symptoms and prior to cortical brain biopsies. All patients had CNS disease clinically compatible with the diagnosis of herpes simplex encephalitis (HSE). The diagnosis was demonstrated by the isolation of virus from the brain in five patients (group 1) but considered highly unlikely in the other 12 patients (group 2) by negative immunofluorescent studies and failure of viral isolation from the brain tissue. Abnormal but nonspecific EEGs with diffuse or focal slowing were found in all patients. Distinctive high-voltage, 1-cycle-per-2-to-3 seconds periodic sharp waves from unilateral temporal lobes were seen only in three of the five patients with virologically proved HSE but in none of the 12 patients without viral isolation. This EEG pattern is strikingly similar in all three patients, regardless of their age, and may be specific for the early diagnosis of HSE prior to brain biopsy. The EEGs of the other two patients with proved HSE did not contain such abnormalities. Athough periodic EEGs with some resemblance to those previously described may occur in other CNS disorders, their presence strongly suggests the diagnosis of HSE when recorded from patients with viral meningoencephalitis. Moreover, EEGs may help locate the best site for cerebral biopsy since maximal yield of the virus in this study was from unilateral temperoal lobes corresponding with the site of local EEG changes.
