Pelvic fractures in a pediatric level I trauma center

OBJECTIVES: Assess the characteristics associated with the risk of complications and mortality in children sustaining pelvic fractures. SETTING: Urban university pediatric Level I trauma center in a large metropolitan community. PATIENTS/PARTICIPANTS: Retrospective analysis of 57 consecutive children with 66 pelvic fractures seen between 1993 and 1999. INTERVENTION: Fifty-two patients were treated nonoperatively, and five patients required operative stabilization (four acetabular fractures and one partial sacroiliac joint disruption). MAIN OUTCOME MEASURE: Type and cause of pelvic fracture, type of management used, incidence of associated injuries, hemorrhage requiring transfusion, and mortality. RESULTS: Hemorrhage directly related to the pelvic fracture occurred in only one patient (2%), whereas 11 other patients required transfusions associated with other body-area injuries. Three patients with pelvic fractures died (5%), but deaths were due to other body-area injuries. CONCLUSIONS: Children with pediatric pelvic fractures require careful evaluation for other body-area injuries, as these are most likely to be related to hemorrhage or mortality.     

Decline in rate of colonization of oligodendrocyte progenitor cell (OPC)-depleted tissue by adult OPCs with age

Rates of remyelination decline with age and this has been attributed to slower recruitment of oligodendrocyte progenitor cells (OPCs) into areas of demyelination and slower differentiation of OPCs into remyelinating oligodendrocytes. When considering causes for reduced recruitment rates, intrinsic causes (alterations in biological properties of OPCs) need to be separated from extrinsic causes (age-related differences in the lesion environment). Using 40 Gy of X-irradiation to deplete tissue of its endogenous OPC-population, we examined the effects of age on the rate at which adult rat OPCs colonize OPC-depleted tissue. We found a significant reduction in the rate of colonization between 2 and 10 months of age (0.6 mm/week versus 0.38 mm/week). To determine if this represented an intrinsic property of OPCs or was due to changes in the environment that the cells were recolonizing, OPCs from 10-month-old animals were transplanted into 2-month-old hosts and OPCs from 2-month-old animals were transplanted into 10-month-old hosts. These experiments showed that the transplanted OPCs retained their age-related rate of colonization, indicating that the decline in colonizing rates of OPCs with age reflects an intrinsic property of OPCs. This age-related decline in the ability of OPCs to repopulate OPC-depleted tissue has implications for understanding remyelination failure in multiple sclerosis (MS) and developing therapies for remyelination failure.     

Delusions of alien control in the normal brain

Delusions of alien control, or passivity experiences, are symptoms associated with schizophrenia in which patients misattribute self-generated actions to an external source. In this study hypnosis was used to induce a similar misattribution of self-generated movement in normal, healthy individuals. Positron Emission Tomography (PET) was employed to investigate the neural correlates of active movements correctly attributed to the self, compared with identical active movements misattributed to an external source. Active movements attributed to an external source resulted in significantly higher activations in the parietal cortex and cerebellum than identical active movements correctly attributed to the self. We suggest that, as a result of hypnotic suggestion, the functioning of this cerebellar-parietal network is altered so that self-produced actions are experienced as being external. These results have implications for the brain mechanisms underlying delusions of control, which may be associated with overactivation of the cerebellar-parietal network.     

Environmental enrichment slows disease progression in R6/2 Huntington's disease mice

Huntington's disease is a genetic disorder that causes motor dysfunction, personality changes, dementia, and premature death. There is currently no effective therapy. Several transgenic models of Huntington's disease are available, the most widely used of which is the R6/2 mouse, because of its rapid disease progression. Environmental enrichment alters gene expression in the normal mouse brain, and modulates the course of several neurological disorders. Environmentally enriched mice may actually mimic human disease more accurately. We found that even limited environmental enrichment slows decline in RotaRod performance in R6/2 mice, despite rapid disease progression, whereas in normal littermates, maximal enrichment was required to induce a marked improvement in behavioral tests. Enrichment also delayed the loss of peristriatal cerebral volume in R6/2 brains. These results could provide the basis for a rational approach to ameliorate the effects of Huntington's disease.     

Areas of demyelination do not attract significant numbers of schwann cells transplanted into normal white matter

If Schwann cell transplantation is to be used as a therapy for demyelinating disease, it is important to know if the number of transplanted cells and their transplantation site affects the extent of remyelination. Primary Schwann cell cultures were obtained from neonatal rat sciatic nerve, purified, and expanded using bovine pituitary extract and forskolin. Areas of persistent demyelination were created in the dorsal funiculus of the thoracolumbar spinal cord of rats by injecting ethidium bromide into white matter exposed to 40 Gy of X-irradiation, and a high and low number of Schwann cells were transplanted, into either the area of demyelination or the dorsal funiculus cranial to the area of demyelination. Animals were perfused 4 weeks after transplantation. After injection of 4 x 10(4) cells into the area of demyelination, the area of Schwann cell remyelination was 0.88 +/- 0.16 mm(2), while following the injection of 3 x 10(3) cells it was significantly smaller, 0.29 +/- 0.09 mm(2). After implantation of Schwann cells 1-3 mm (mean 2.5 mm) cranial to the area of demyelination, only one of the eight animals (a high-dose animal) showed extensive Schwann cell remyelination. In this animal, the cells were transplanted within 1 mm of the area of demyelination, well within the length of tissue over which cells are passively spread by the injection procedure (1-3 mm). Our results show that significant numbers of transplanted Schwann cells are not attracted through normal tissue to areas of demyelination and when transplanted into areas of demyelination the extent of myelination is related to the number of Schwann cells transplanted.     

Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis

Rademaker KJ, Groenendaal F, Jansen GH, Eken P, de Vries LS. Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis. Acta Pædiatr 1994;83:602–8. Stockholm. ISSN 0803–5253 In a prospective cranial ultrasound study of 544 infants with a gestational age of 32 weeks or less, 20 (3.6%) infants were diagnosed as having a unilateral parenchymal lesion (PL). Based on the shape of the PL and the evolution on ultrasound, the infants were divided into three groups: group I consisted of 11 infants, in whom the PL was triangular/fan-shaped and separate from the ventricle. The PL evolved into small cystic lesions; group II comprised 3 infants who had a PL with a similar shape, but partially communicating with the ventricle; group III consisted of 6 infants who had a globular-shaped lesion in communication with the ventricle. In groups II and III, the PL evolved into one porcncephalic cyst. The PL was considered to be due to venous infarction in all cases with intraventricular haemorrhage preceding the PL in 7 cases. Sixteen infants survived. A postmortem was performed in 2 of the 4 infants who died, confirming the diagnosis of venous infarction. Neurologicdl sequelae were present in only 2 cases in the first group, while all 6 survivors of the other two groups developed mild to severe hemiplegia. Long-term follow-up was not always available and 4 of the 18 survivors were still less than 18 months when last seen. In 9 of the 11 infants in group I, the PL was localized in the frontoparietal region, while in 8 of the 9 infants in group II or III, the PL was beyond the trigone in the occipital region. The outcome of the unilateral PL is not always unfavourable. It was evident that not only the shape of the lesion and whether or not there was communication with the lateral ventricle, but also the site of the lesion (whether or not it extended into the occipital periventricular white matter) appeared to be important with regard to neurodevelopmental outcome.     

Direction discrimination of moving gratings and plaids and coherence in dot displays without primary visual cortex (V1)

We present new experimental observations of G.Y., a well-tested patient with unilateral loss of primary visual cortex. We stimulated G.Y.'s blind hemifield using first- and second-order motion stimuli at velocities around psychophysical threshold. Using a dual response paradigm (awareness level of visual motion, motion direction discrimination) psychophysical performance improved with increasing velocity and dot coherence. We were also able to influence directly G.Y.'s performance for the better and at will, by placing the emphasis solely on direction discrimination. In the absence of V1, graduated detection and discrimination of stimuli known to activate both V1 and extrastriate motion areas MT/V5 and MST is still possible. These results are in line with residual visual processing but did not show evidence of unconscious processing of motion stimuli characteristic of ‘blindsight’.     

Technical evaluation of factors interfering in the carcinoembryonic antigen assay

Storage of serum or plasma at room temperature (RT) or 4 degrees C for eight days did not alter the level of carcinoembryonic antigen (CEA). However, storage of whole blood at RT for 8 days resulted in false elevated CEA levels compared to controls. Heating of serum or plasma at 56 degrees C for 30 min or freezing and thawing for fifteen times did not change the CEA levels in these specimens. Comparison of CEA levels in the serum and plasma of the same specimens showed significantly higher levels of CEA in plasma than serum specimens. Collection of blood in tubes with different anticoagulants showed significantly false elevated levels of CEA only when blood was collected in heparinized tubes. These data indicate the importance of knowing the factors interfering in the CEA assay when interpreting its results.     

Ultrasonic features of pyogenic liver abscesses

Ultrasonic features of 21 surgically confirmed pyogenic liver abscesses in 18 patients were analyzed. Typical lesions were round or ovoid with a discrete, irregular, echo-poor margin. The number and intensity of internal echoes and sound transmission were variable. Such lesions can be aspirated percutaneously for definitive preoperative diagnosis. Pyogenic liver abscesses appear to have more ragged walls and are less frequently elliptical or multilocular than abscesses elsewhere in the abdomen.