The group-specific murine coronavirus genes are not essential,but their deletion,by reverse genetics,is attenuating in the natural host

In addition to a characteristic set of essential genes coronaviruses contain several so-called group-specific genes. These genes differ distinctly among the three coronavirus groups and are specific for each group. While the essential genes encode replication and structural functions, hardly anything is known about the products and functions of the group-specific genes. As a first step to elucidate their significance, we deleted the group-specific genes from the group 2 mouse hepatitis virus (MHV) genome via a novel targeted recombination system based on host switching (L. Kuo, G. J.Godeke, M. J. Raamsman, P. S. Masters, and P. J. M. Rottier, 2000, J. Virol. 74, 1393-1406). Thus, we obtained recombinant viruses from which the two clusters of group-specific genes were deleted either separately or in combination in a controlled genetic background. As all recombinant deletion mutant viruses appeared to be viable, we conclude that the MHV group-specific genes are nonessential, accessory genes. Importantly, all deletion mutant viruses were attenuated when inoculated into their natural host, the mouse. Therefore, deletion of the coronavirus group-specific genes seems to provide an attractive approach to generate attenuated live coronavirus vaccines.     

Air following splenic embolization: infection or incidental finding?

The use of splenic embolization for nonoperative management has increased. With increased use of this adjunct, a new and frequent finding has been air within the areas of infarction in patients with or without clinical signs of infection. The purpose of this study was to determine if air within areas of splenic infarction is pathologic of infection or rather an incidental finding. A retrospective review over the past 3 years of inpatients undergoing splenic embolization and having pre- and postembolization abdominal computed tomography scans were reviewed for the findings of free air as well as any clinical signs of infection. A total of 96 consecutive patients were included. Of these, 12 had evidence of infarction with air. Six of these patients had undergone distal embolization with intraparenchymal air, but no symptoms. These were successfully observed. Two patients demonstrated subcapsular air/fluid levels, which underwent drainage with splenic preservation. Cultures were negative for infection. The remaining 4 underwent splenectomy. Of these, all had large collections of air. Two of these 4 spleens were infected: 1 with alpha-hemolytic Streptococcus and one with Clostridia perfringens. The remainder was sterile. This gave an overall infection rate of 17 per cent of patients with evidence of air. This yield increased to 33 per cent if the patient had symptoms and 50 per cent in those with large amounts of air and symptoms. Overall, we feel that air following embolization is a concern, but does not constitute infection. Patients with large amounts of air and signs and symptoms of infection will have a far higher infectious rate, 50 per cent in this limited series. In these patients, evaluation for infection is indicated; that being percutaneous sampling versus splenectomy.     

The clinical geneticist and the "new genetics"

The "new genetics" will provide new genetic tests that can be used for diagnosis, prognosis, treatment selection, carrier and predictive testing in affected families, and potentially for susceptibility testing for later-onset multifactorial disease and population screening. Doctors will increasingly need to consider the family implications of a genetic diagnosis--to identify family members at risk of the disorder or of having affected children and to consider how these individuals might be advised of their situation. Clinical geneticists can be a valuable resource for doctors who need advice about whether genetic testing is available, which tests to pursue, how to access testing services, and how to interpret and act on test results. Clinical geneticists also provide genetic counselling, a process which gives people understandable information about the genetic disorder in the family, and makes the information useful for decision-making given the person's unique circumstances and beliefs. The Internet will increasingly be a key source of information about genetic disorders for patients, their families and healthcare professionals.     

ERP abnormalities of illusory contour perception in Williams syndrome

Williams syndrome is a genetic disorder in which visuo-spatial performance is poor. Theorists have claimed that the deficit lies in high-level processing, leaving low-level visual processes intact. We investigated this claim by examining an aspect of low-level processing, perceptual completion, i.e. the ability of this clinical group to perceive illusory Kanizsa squares. We then used event-related potentials to examine neural correlates of perceptual completion. While participants were able to perceive illusory contours, the neural correlates of this apparently normal perception were different from controls. Such differences in low-level visual processes may significantly impact on the development of higher-level visual processes. We conclude that, contrary to earlier claims, there is atypical neural processing during low-level visual perception in Williams syndrome.     

Cognitive functioning in patients with a small infarct in the brainstem.

Earlier findings in patients with a small supratentorial white matter infarct demonstrated subtle impairments of cognition. This is in line with reported difficulties in regaining premorbid level of functioning in daily life activities, even though any physical neurological deficits are no longer present. Either a "bystander effect" of adjoining gray matter or a long distance effect through hypometabolism or other neurochemical changes might underlie these impairments. To find the best explanation, a group of 17 patients with a lacunar infarct in the brainstem was neuropsychologically evaluated and compared with a closely matched control group. The patients demonstrated significantly impaired task performance on a constellation of neuropsychological tasks that was very similar to the findings previously found in patients with a supratentorial lacunar infarct (Boston Naming Test, TEA visual elevator, category fluency, Trailmaking Test). We conclude that a small white-matter infarct may affect cognitive functioning in a nonspecific way independently of its location.     

Cortical specialisation for face processing: face-sensitive event-related potential components in 3- and 12-month-old infants

The adult N170 is considered to be an electrophysiological marker of specialised mechanisms for face processing, but little is known about its developmental origin. Previous work has identified two face-sensitive infant ERP components (N290 and P400) (J. Cog. Neurosci. 14 (2002), 199). In the present study, we assessed the specificity (to upright human faces) of these infant components at 3 and 12 months. At 12 months the degree of specificity observed in both components was similar to that seen in the adult N170. In contrast, at 3 months of age the N290 and P400 did not show the same level of specificity for human faces as that observed at 12 months. Our findings suggest that (1) both face-sensitive components increase in their specificity for upright human faces during development, and (2) the adult N170 is not preceded by a single developmental precursor, but rather emerges as a consequence of the integration of two functionally and morphologically distinct components (N290 and P400).     

Contractile speed and fatigue of adductor pollicis muscle in multiple sclerosis

The purpose of the study was to investigate differences in contractile speed, force, and fatigability of the adductor pollicis muscle between 12 patients with multiple sclerosis (MS) and 8 sedentary control subjects matched for age and gender. There were no differences between the patients with MS and control subjects with respect to the percentage of maximal muscle force that could be recruited during voluntary effort (95.5 +/- 3.9% and 98.2 +/- 2.0%, respectively, P = 0.10), the stimulation frequency/force and force/velocity relationships, the rates of force development and relaxation, fatigue resistance, and the recovery rate of adductor pollicis muscle. However, previous results from the same group of MS patients showed that quadriceps femoris muscle force and resistance to fatigue were reduced. Therefore, our data support the clinical experience that, in patients with MS, lower limb muscle function is more or earlier affected than upper limb muscle function.     

Effects of slow rTMS at the right dorsolateral prefrontal cortex on EEG asymmetry and mood

In a sham-controlled design (n = 12), slow repetitive transcranial magnetic stimulation (rTMS) was applied to the right dorsolateral prefrontal cortex for 20 min, and the subsequent effects on mood and the EEG spectrum were investigated, Analysis revealed a significant left hemisphere increase in EEG theta activity at 25-35 and 55-65 min after stimulation. In addition, participants reported significant decrease in anxiety immediately after stimulation, as well as 35 and 65 min after rTMS. These findings indicate that reductions in anxiety after slow rTMS at the right dorsolateral prefrontal cortex are associated with a contralateral increase in theta activity.     

Posterior approach for the simultaneous, bilateral thoracoscopic sympathectomy

If there is an indication for sympathectomy in the case of severe hyperhidrosis or rubeosis, in our opinion the posterior approach is preferable because of the advantages in surgical technique and anesthesia. Bilateral treatment can be accomplished in a single admission, with all the concomitant advantages.