Unusual fractures and dislocations of the axis vertebra

Seven percent of 400 patients with cervical spine fractures and/or dislocations had unusual lesions of the axis. The authors have analyzed axis injuries by review of radiographs and clinical data and have derived a classification of traumatic conditions. Uncommon traumatic axis abnormalities are discussed with reference to incidence, causes, clinical findings, mechanism of injury, and roentgen characteristics.Picker Scholar, James Picker Foundation     

Dopaminergic neuronal responses to a non-amphetamine CNS stimulant

Summary The present study compares the effects of d-amphetamine (d-AMP) and the potent non-amphetamine CNS stimulant, amfonelic acid (AFA), on the firing rate of single midbrain dopaminergic (DA) neurons and on neostriatal DA metabolism (dihydroxyphenylacetic acid—DOPAC). The results indicate that AFA, like d-AMP, reduces the firing rate of DA neurons, although unlike d-AMP, AFA does not cause a decrease in neostriatal DOPAC content and, in fact, enhances that produced by haloperidol (HALO). The AFA-induced decrease in firing rate, like d-AMP, is reversed by the DA receptor blocker HALO, but again unlike d-AMP, the decrease in firing rate is not prevented by catecholamine synthesis inhibition with-methyl-para-tyrosine. Thus, both amphetamine and amfonelic acid have identical electrophysiological effects on DA neurons but act by different mechanisms.     

Use of plasma products with whole blood and packed RBCs.

During the past five years, there has been a sharp increase in the use of packed RBCs (PRBCs) and plasma products, whereas whole blood (WB) transfusions have steadily decreased. In order to determine whether plasma and its derivatives were being used to "reconstitute" whole blood from PRBCs, we performed a retrospective evaluation of all transfusion episodes in ten representative regional hospitals during a five-month period. Our results indicate that PRBCs were transfused 2.5 times more frequently than WB. Plasma products were administered with PRBCs less often than with WB: 14% of all PRBCs vs 24% of all WB units tranfused. The likelihood of a patient receiving plasma was found to correlate with the total amount of blood transfused and the frequency of transfusion. This study provides evidence that, at most, only a small percentage of PRBCs are given in conjunction with plasma as "reconstituted" WB.     

The enhancement of beta-lactam antibiotic therapy by novobiocin

Novobiocin demonstrates an effect similar to that of probenecid (the "probenecid effect") in enhancing the therapeutic efficacy of antibiotics excreted mainly by the renal tubules. The ability of cefoxitin, cephalexin, cephalothin and penicillin G to protect mice against infection with Salmonella schottmuelleri was enhanced 2- to 3-fold when the animals were given oral doses of either probenecid or of novobiocin. The efficacy of cephaloridine, excreted mainly by glomerular filtration, was not enhanced by either probenecid or by novobiocin.     

Variations in T1 and T2 relaxation times of normal appearing white matter and lesions in multiple sclerosis

OBJECTIVE: To investigate the variation in T1 and T2 relaxation times of normal appearing white matter (NAWM) and lesions in multiple sclerosis (MS) throughout the brain. BACKGROUND: The magnetic resonance imaging (MRI) sequence fast FLAIR (fluid attenuated inversion recovery) has demonstrated overall increased lesion detection when compared to conventional or fast spin echo (FSE) but fewer lesions in the posterior fossa and spinal cord. The reasons for this are unknown, but may be due to variations in the T1 and T2 relaxation times within NAWM and MS lesions. METHOD: Ten patients and 10 controls underwent MRI of the brain which involved FSE, fast FLAIR and the measurement of T1 and T2 relaxation times. RESULTS: Of 151 lesions analysed (22 infra-tentorial, 129 supra-tentorial), eight were missed by the fast FLAIR sequence. T1 and T2 relaxation times in normal controls were longer in the infra-tentorial, than supra-tentorial, region. Patient NAWM relaxation times were prolonged compared with control values in both regions. Lesions demonstrated longer relaxation times than either control white matter or patient NAWM in both regions, however this difference was less marked infra-tentorially. The eight posterior fossa lesions not visible on the fast FLAIR sequence were characterised by short T1 and T2 relaxation times which overlapped with the patient NAWM for both T1 and T2 and with control values for T2 relaxation times. CONCLUSION: Both lesion and NAWM relaxation time characteristics vary throughout the brain. The T1 and T2 relaxation times of infra-tentorial lesions are closer to the relaxation times of local NAWM than supra-tentorial lesions, resulting in reduced contrast between posterior fossa lesions and the background NAWM. Consequently the characteristics of some lesions overlap with those of NAWM resulting in reduced conspicuity. By utilising this information, it may be possible to optimise fast FLAIR sequences to improve infra-tentorial lesion detection.     

Do specific neurocognitive deficits predict specific domains of community function in schizophrenia?

We examined whether specific neurocognitive deficits predicted specific domains of community outcome in 40 schizophrenic patients. Neuropsychological assessments were conducted before hospital discharge, and measures of functional outcome were obtained 1 to 3.5 years later. A priori hypotheses were generated based upon a recent review by Green (Green MF [1996] What are the functional consequences of neurocognitive deficits in schizophrenia? American Journal of Psychiatry, 153(3):321-330). As hypothesized, verbal memory predicted all measures of community outcome, vigilance predicted social outcomes, and executive functioning predicted work and activities of daily living (ADLs). However, in addition to the predicted relationships, many other associations were found between neuropsychological test scores and adaptive function. Furthermore, both cognitive and functional measures were intercorrelated. If deficits in adaptive functioning are neurocognitively multi-determined, utilizing compensatory strategies to bypass multiple areas of cognitive impairment may be more efficient than cognitive remediation in improving community outcomes.     

Posttraumatic stress two years after the Oklahoma City bombing in youths geographically distant from the explosion

This article describes Posttraumatic Stress Disorder (PTSD) symptomatology in 69 sixth-grade youths who resided within 100 miles of Oklahoma City at the time of the 1995 bombing of the Alfred P. Murrah Federal Building. These youths neither had any direct physical exposure nor personally knew anyone killed or injured in the explosion. A survey conducted two years after the bombing assessed exposure, PTSD symptoms, and functioning. PTSD symptom frequency was measured with the Impact of Event Scale--Revised. Our BCD criteria for defining PTSD caseness was modeled after DSM-IV B, C, and D criteria requiring one reexperiencing, three avoidance/numbing, and two arousal symptoms for diagnosis. Those who met our BCD criteria had significantly higher PTSD symptom scores than those who did not. Both increased mean PTSD symptom score and meeting our caseness definition were associated with increased functioning difficulties. Media exposure and indirect interpersonal exposure (having a friend who knew someone killed or injured) were significant predictors of symptomatology. These findings suggest that children geographically distant from disaster who have not directly experienced an interpersonal loss report PTSD symptoms and functional impairment associated with increased media exposure and indirect loss.