A Test to Detect Chest Tube Kinking

Objectives: To determine whether the Mac‐technique test can detect kinking of the chest tube upon thoracostomy tube placement. Methods: This was a prospective observational study that was conducted October 2000 through October 2001 in an urban Level 1 trauma center. There were 103 consecutive nonrandomized adult trauma patients who required immediate tube thoracostomy during their initial resuscitation who were entered into the study. The Mac‐technique test was performed during standard tube thoracostomy insertion to the appropriate depth. The test involved grasping the external portion of the thoracostomy tube, turning it clockwise 180°, and then releasing the tube. If the tube spontaneously spun back to its original position, the test was considered positive, and the tube was considered kinked. If the tube did not spontaneously spin back and stayed in position upon release, the test was considered negative. Regardless of the results of this test, the tube was secured, and a postprocedure chest radiograph was obtained. The criterion standard for determining a kinked chest tube was its appearance on this chest radiograph. Results: A total of 103 chest tubes were placed by using the Mac‐technique test. The test was positive in eight placements; four tubes were kinked on chest radiograph. The Mac‐technique test was negative in 95 placements; four tubes were kinked on chest radiograph. The Mac technique had a sensitivity of 50% (95% confidence interval [CI] = 15.7% to 84.3%), a specificity of 95.8% (95% CI = 89.6% to 98.8%), a positive likelihood ratio of 11.9, a negative likelihood ratio of 0.52, and an odds ratio using Yates correction of 20.3 (95% CI = 4.1 to 102.1). Conclusions: On the basis of this study, a positive Mac‐technique test is useful to detect chest tubes that are likely to be kinked after insertion and before securing.     

Construction and validation of a Parkinson's disease mutation genotyping array for the Parkin gene.

Parkin mutations account for the majority of familial and sporadic early onset Parkinson's disease (EOPD) cases with a known genetic association. More than 100 mutations have been described in the Parkin gene that includes homozygous, compound heterozygous, and single heterozygous mutations. We have designed a Parkin mutation genotyping array (gene chip) that includes published Parkin sequence variants and allows their simultaneous detection. The chip was validated by screening 85 PD cases and 47 controls previously tested for Parkin mutations. Similar genotyping microarrays have been developed for other genetically heterogeneous diseases including age-related macular degeneration. Here, we show the utility of a genotyping array for Parkinson's disease by analysis of 60 subjects from the Genetic Epidemiology of Parkinson Disease (GEPD) study that includes 15 early-onset PD case probands and 45 relatives.     

Impaired motor imagery in patients with essential tremor: a case control study.

Motor imagery (MI), which refers to the process of mental representation of movements, has not been studied in patients with essential tremor (ET). We investigated the presence of impaired MI in ET patients compared with healthy controls. A group of drug-naive and nondemented ET patients and age-matched controls were studied using transcranial magnetic stimulation, while they were specifically instructed to try and imagine themselves performing two motor tasks. The various clinical and electrophysiological variables were evaluated and compared. Repeated measures ANOVA demonstrated a significant difference between ET patients and controls with respect to mean motor-evoked potential (MEP) amplitudes (F(1,38) = 31.92, P < 0.005) during MI. The process of MI effectively facilitated MEP amplitude in controls but not in ET patients, regardless of side of stimulation or motor tasks. We provide evidence to demonstrate impairment of MI in a group of ET patients compared with healthy controls. The basis for this novel finding is unclear, and further studies are warranted to determine whether it is related to cerebellar or motor cortical dysfunction.     

Effects of a specific benzodiazepine antagonist (RO 15-1788) on cerebral blood flow

RO 15-1788, a specific benzodiazepine antagonist, although it effectively antagonizes the clinical effects of benzodiazepines (i.e., sedation and amnesia), can also induce subjective agonist effects such as sedation or inverse agonist effects such as anxiety. The purpose of this study was to investigate in seven healthy volunteers the effect of RO 15-1788 on cerebral blood flow when intravenously injected alone or with midazolam and to compare its effects with midazolam administered alone. Cerebral blood flow was measured with the 133xenon inhalation technique and the drugs were administered simultaneously in a double-blind, randomized fashion during the four following sessions: placebo-placebo; midazolam-placebo; RO 15-1788-placebo; midazolam-RO 15-1788. No difference in cerebral blood flow was noted between the placebo-placebo, the RO 15-1788-placebo, and the RO 15-1788-midazolam sessions--although midazolam injected alone decreased cerebral blood flow by 30%. The sedation, amnesia, and the electroencephalograph (EEG) and muscle tone changes observed with midazolam-placebo were not present during the RO 15-1788-placebo and RO 15-1788-midazolam sessions. This study demonstrates the absence of effects of RO 15-1788 on cerebral blood flow when injected alone and the efficacy of this new drug in antagonizing the depressant effects of midazolam on cerebral hemodynamics.     

Locus ceruleus lesions and eosinophilic inclusions in MPTP-treated monkeys

Systemic administration of the recently discovered neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces severe clinical parkinsonism and degeneration of the substantia nigra in humans and monkeys. In previous studies, no convincing structural damage to nerve cells outside the substantia nigra could be demonstrated in subhuman primates. Using a protracted MPTP regimen and older animals, we now report locus ceruleus lesions and eosinophilic inclusion bodies in squirrel monkeys. The inclusions were seen only in areas where Lewy bodies are found in human Parkinson's disease. No such abnormalities were seen in control animals. These findings suggest that similarities between the neuropathology of MPTP-induced parkinsonism in the monkey and human Parkinson's disease are greater than first thought and increase the usefulness of the MPTP monkey model for research in Parkinson's disease.     

In Vitro Growth of Thymic Tumor Cell Lines from Xenopus

A spontaneous lymphoid thymus tumor was discovered in a male Xenopus of the MHC ff genotype. The tumor cell can be transplanted in histocompatible larval ff hosts, but not in ff adults unless irradiated (3000 rad). The tumor is rejected by allogeneic hosts. The tumor cells express neither markers of the B-cell lineage nor MHC encoded molecules; they express only markers of the T-cell lineage. Its lymphoid population is clonal as revealed by the existence of a stable rearrangement pattern of the immunoglobulin genes. Cell lines growing continuously in vitro have been derived from the tumor.