Caring for patients with traumatic injuries of the thoracic aorta.

Trauma is a major cause of mortality and morbidity in the United States, with blunt traumatic injuries of the thoracic aorta continuing to occur despite the increased use of seatbelts and airbags. Emerging from crash analysis are effective interventions and provides increased awareness of the occult nature of these types of injuries. This article describes those interventions that healthcare providers must embed throughout the continuum of care for patients experiencing thoracic aortic injuries. Outcomes will be dependent upon the healthcare provider's knowledge of the physics of the event and the urgency of the diagnosis, as well as the ability to assess and manage all the variables involved. Current procedural issues are delineated and case studies are used to illustrate the processes of care needed by these patients.     

Syntactic language processing: ERP lesion data on the role of the basal ganglia.

The role of the basal ganglia in syntactic language processing was investigated with event-related brain potentials in fourteen neurologically impaired patients. Seven of these patients had basal ganglia lesions while 7 other patients primarily had lesions of the left temporo-parietal region excluding the basal ganglia. All patients listened to sentences that were either correct or included a verb argument structure violation. In previous experiments this type of violation elicited a biphasic pattern of an N400-P600 complex in young healthy participants. While the N400 may result from incorrect semantic-thematic role assignment, the P600 reflects the fact that verb information does not license the syntactic structure at present. Results of the patient experiment revealed a double dissociation: patients with left temporo-parietal lesions only show a P600, whereas patients with lesions of the basal ganglia showed no P600, but a negativity with extended duration that resembled an N400. The latter pattern not only confirms previous reports that the basal ganglia modulate the P600 but extends these results by showing that the N400 as a late semantic-thematic integration process appears partially modulated by the basal ganglia.     

Inhibition of rat hippocampal excitability by the plant alkaloid 3-acetylaconitine mediated by interaction with voltage-dependent sodium channels

The effects of the Aconitum alkaloid 3-acetylaconitine on neuronal activity were investigated in the slice preparation and on cultivated neurons of rat hippocampus by extracellular and patch-clamp recordings, respectively. 3-Acetylaconitine (0.01–1 μM) diminished the orthodromic and antidromic population spike in a concentration-dependent manner. The inhibitory action of the drug was preceded by a transiently enhanced excitability. The latency of onset of the inhibition was accelerated by increased stimulation frequency, whereas recovery during washout of the alkaloid was accelerated by decreased stimulation frequency. Moreover, the inhibitory effect of 3-acetylaconitine was evaluated in two different models of epileptiform activity induced either by blockade of GABA receptors by bicuculline (10 μM) or by a nominal Mg²⁺-free bathing medium. In accordance with the activity-dependent mode of action, this compound abolished the synaptically evoked population spikes in the presence of bicuculline or nominal Mg²⁺-free bathing medium, respectively. Whole-cell patch-clamp recordings revealed an interaction of 3-acetylaconitine with the voltage-dependent sodium channel. At a concentration of 1 μM, 3-acetylaconitine did not affect the peak amplitude of the sodium current, but shifted the current-voltage relationship in the hyperpolarized direction such that sodium currents were already activated at the resting potential. Received: 22 July 1996 / Accepted: 14 October 1996     

Estradiol and tryptophan depletion interact to modulate cognition in menopausal women.

Despite an abundance of data in animals, there is little research in humans regarding how estrogen and serotonin (5-HT) may interact to influence cognition. Through the use of estrogen treatment (ET) and tryptophan depletion (TRP-D) in a within-subject design involving healthy menopausal women, we have manipulated both estrogen and 5-HT in order to evaluate their individual and joint effects. Although neither manipulation influenced visuospatial learning, a significant interaction suggested that estrogen exerted a protective effect on verbal memory, such that TRP-D impaired performance to a greater extent before the administration of ET. In consonance with this finding, ET was associated with a small, but positive mood effect on the day following active TRP-D. In addition, ET significantly improved letter-cued verbal fluency with and without TRP-D. Finally, time since last menstrual period was significantly associated with verbal memory scores, such that longer length of hypogonadism resulted in decreased verbal memory performance. These data support the interaction of estrogen and 5-HT in nonreproductive behavior in humans as well as highlight the role of ovarian steroids in cognition.     

p53 and skin carcinomas with skull base invasion: a case-control study.

BACKGROUND: Some skin carcinomas may be very aggressive. Increased expression of the protein p53 has been associated with tumor aggressiveness. In this study, p53 expression was evaluated in basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) with skull base invasion, and was compared to tumors with good outcome. STUDY DESIGN AND SETTING: Expression of p53 was immunohistochemically analyzed and it was reported as present or absent in 24 BCC and 11 SCC with skull base invasion. Control group (good outcome) included 23 BCC and 10 SCC. RESULTS: Expression of p53 was noted in 70.83% of BCC with skull base invasion, compared to 43.48% in the control group (P = 0.058). Regarding SCC, p53 positivity was noted in only 9.09% of SCC with skull base invasion, compared to 40.00% in the control group (P = 0.149). CONCLUSIONS: In this study, p53 expression was more common among BCC with skull base invasion, compared to controls with good outcome, and the difference was considered marginally significant. This proportion was reversed in SCC, but the difference was not statistically significant. EBM rating: B-3b.     

Artifacts due to stimulus correlated motion in functional imaging of the brain

To assess the effect of stimulus correlated motion on the appearance of functional magnetic resonance images, conventional visual and motor protocols were each performed by four normal volunteers and an image co-registration technique was used to retrospectively monitor subject motion. In three studies synthetic data sets were constructed from single baseline images using the positional information obtained from the co-registration procedure. Cumulative difference images were then created from both the synthetic and functional image sets. Stimulus correlated motion was detected in all eight studies and the synthetic cumulative difference images showed striking similarities to the equivalent functional images in each case.     

Relationship between Mandarin speech reception thresholds and pure-tone thresholds in the geriatric population.

BACKGROUND/PURPOSE: In the geriatric population, the reliability of pure-tone threshold (PTT) is sometimes poorer than that in young adults because of various reasons. This study assessed the relationship between Mandarin speech reception thresholds (SRTs) and PTTs in the aged and developed SRT as a measure for corroborating PTT. METHODS: This prospective study enrolled 46 consecutive subjects over 60 years of age. The results of SRT and PTT were collected from one ear randomly selected from each subject. Simple linear and multiple regressions were used to determine the correlation and linear regression coefficients between SRTs and PTTs at various frequencies. RESULTS: In the simple regression analysis, the correlation coefficient was highest at 1000 Hz (r = 0.949) and 500 Hz (r = 0.922), followed by 250 Hz (r = 0.850) and 2000 Hz (r = 0.792). In the multiple regression model with SRT as the dependent variable and PTTs as predictor variables, the resultant multiple correlation coefficient R was 0.967, while R2 was 0.936. In this model, PTTs at the frequencies of 500 Hz and 1000 Hz contributed significantly to the variance in SRTs with p values of 0.029 and < 0.001, respectively. These results demonstrated that the Mandarin SRT is strongly associated with PTTs at the frequencies of 500 Hz and 1000 Hz. CONCLUSION: This study established the agreement between Mandarin SRTs and PTTs in the low tone area of speech frequencies in the geriatric population. In clinical settings, SRT test can be rapidly and easily performed and is relatively inexpensive. It is a vital indicator of the accuracy of PTT measurement.     

Chest hair micrografts display extended growth in scalp tissue: a case report.

Conventional follicle harvesting techniques for hair transplantation are limited by the available scalp donor hair. The development of an innovative technique of microsurgical single follicular unit extraction has made it possible to exploit body hair grafts for scalp transplantation. This case study reports on 18 months of follow-up on a patient with extensive scalp scarring who underwent a transplantation procedure using donor chest hair. The photographically documented results show a change in the length of the chest hair measuring an average of 4 cm at transplant to 15 cm by 18 months post-transplant. The transplanted chest grafts provided an excellent cosmetic result for hair replacement.