Injury of the corticobulbar tract in patients with dysarthria following cerebral infarct: diffusion tensor tractography study

Objectives: Little is known about injury of the corticobulbar tract (CBT) in stroke patients. We attempted to investigate injury of the CBT in patients with dysarthria following cerebral infarct, using diffusion tensor tractography (DTT). Methods: Eight patients with dysarthria following a corona radiata infarct and 12 control subjects were recruited for this study. Diffusion tensor imaging was performed at 14.3 days after onset and reconstruction of the CBT was performed using the probabilistic tractography method. Fractional anisotropy, mean diffusivity, and tract volume of the CBT were measured. Results: Reconstructed CBTs in the affected hemisphere of the patient group were thinner than those of the unaffected hemisphere of the patient group and the control group. Regarding the DTT parameters of the CBTs, fractional anisotropy and tract volume were significantly lower in the affected hemisphere of the patient group than in the unaffected hemisphere of the patient group and the control group (p < 0.05). However, we did not observe any difference in the mean diffusivity value (p > 0.05). Conclusions: We demonstrated injury of the CBT in patients with dysarthria following cerebral infarct in the corona radiata using DTT. This result indicates the importance of CBT evaluation for dysarthria in patients with cerebral infarct. Therefore, we suggest that evaluations of the CBT using DTT would be useful for patients with dysarthria following cerebral infarct.     

Evaluation of radial and ulnar blood flow after radial artery cannulation with 20- and 22-gauge cannulae using duplex Doppler ultrasound

This study evaluated ulnar and radial artery blood flow after radial artery cannulation during general anaesthesia using Doppler ultrasound. A total of 80 patients were randomly assigned to receive radial artery cannulation with either a 20‐G or 22‐G cannula. Arterial diameter, peak systolic velocity, end‐diastolic velocity, resistance index and mean volume flow were measured at four time points in both arteries: before anaesthesia; 5 min after intubation; immediately after cannulation; and 5 min after cannulation. After radial artery cannulation, ulnar diameters and blood flow were significantly increased, and persisted until 5 min after cannulation. Radial blood flow was decreased immediately after cannulation and recovered to pre‐cannulation values 5 min after cannulation. There were no statistical differences between groups at each time point. Radial artery cannulation causes compensatory increase in ulnar artery blood flow, and the difference in cannula size has minimal effect on this change.     

Utility of tibial tubercle osteotomy in the setting of periprosthetic infection after total knee arthroplasty

Purpose

This study reports radiographic and clinical treatment outcomes of tibial tubercle osteotomy (TTO) used for two-stage revision total knee arthroplasty (TKA) in the setting of periprosthetic infection.

Methods

Thirty-six patients with 51 TTOs used for infected TKA were retrospectively analysed from 2000 to 2010. In 15 of 36 patients, TTO was used in a sequential manner during both first and second stage procedures. The mean follow-up period was 57?months (range seven–126?months).

Results

The mean pre-operative range of knee motion was 40° (range 10–90°), and at latest follow-up it was 92° (range 50–140°). The Knee Society knee scores and function scores were 47 and 9 pre-operatively and 82 and 72 at latest follow-up, respectively. Bony union was achieved in all cases except one nonunion of an avulsion fragment of the osteotomy segment without functional deterioration.

Conclusions

TTO can be a useful extensile surgical approach for treatment of infected TKA with satisfactory clinical and radiographic outcomes.     

Misexpression of Dickkopf-1 in endothelial cells, but not in chondrocytes or hypertrophic chondrocytes, causes defects in endochondral ossification

Developing cartilage serves as a template for long-bone development during endochondral ossification. Although the coupling of cartilage and bone development with angiogenesis is an important regulatory step for endochondral ossification, the molecular mechanisms are poorly understood. One possible mechanism involves the action of Dickkopf (DKK), which is a family of soluble canonical Wnt antagonists with four members (DKK1-4). We initially observed opposite expression patterns of Dkk1 and Dkk2 during angiogenesis and chondrocyte differentiation: downregulation of Dkk1 and upregulation of Dkk2. We examined the in vivo role of Dkk1 and Dkk2 in linking cartilage/bone development and angiogenesis by generating transgenic (TG) mice that specifically express Dkk1 or Dkk2 in chondrocytes, hypertrophic chondrocytes, or endothelial cells. Despite specific expression pattern during cartilage development, chondrocyte- and hypertrophic chondrocyte-specific Dkk1 and Dkk2 TG mice showed normal developmental phenotypes. However, Dkk1 misexpression in endothelial cells resulted in defects of endochondral ossification and reduced skeletal size. The defects are caused by the inhibition of angiogenesis in developing bone and subsequent inhibition of apoptosis of hypertrophic chondrocytes and cartilage resorption.     

Opinions on the Preclinical Evaluation of Novel Therapies for Spinal Cord Injury: A Comparison between Researchers and Spinal Cord-Injured Individuals

Abstract We previously conducted a survey to gather the opinions and perspectives of scientific and clinical researchers on what levels of preclinical evidence were needed to justify translating a promising neuroprotective or neuroregenerative therapy in spinal cord injury (SCI) into a human clinical trial (Kwon et al., 2010 ). Here we conducted an analogous survey of individuals living with SCI in which we gathered their expectations for the levels of preclinical evidence achieved by researchers in substantiating the neuroprotective and neuroregenerative therapies being offered to them in clinical trials. In total, 214 individuals with SCI completed the survey, and their responses were compared to the responses of the 235 scientists and clinicians who completed our previous survey. SCI individuals were more likely than SCI researchers to opine that demonstrating efficacy and safety in rodent models of SCI alone is sufficient to proceed with clinical trials. However, SCI individuals also reported strong support for large animal and primate model studies, and in the case of the latter, were actually more in agreement for the need for primate studies than researchers. SCI individuals also reported strong support for independent replication studies. In general, individuals with SCI had high expectations for the levels of preclinical evidence required to justify translating novel therapies into clinical trials. These expectations should be considered in the decisions to translate specific experimental therapies for SCI.     

Wilms' tumor in a horseshoe kidney

The incidence of horseshoe kidney is about 1 in 400 cases. The presence of Wilms' tumor with a horseshoe kidney is unusual, and the occurrence of Wilms' tumor in a horseshoe kidney is estimated at 0.4 to 0.9% of all Wilms' tumors. We report the case of a 5-year-old boy who presented with a stage IV Wilms' tumor in a horseshoe kidney. The patient was treated with preoperative chemotherapy followed by surgical resection and adjuvant chemotherapy. This case illustrates the role of preoperative chemotherapy for preserving renal function and aims to highlight the multimodality treatment of Wilms' tumor.     

Cell proliferation and neuronal differentiation in the dentate gyrus in juvenile and adult rats following traumatic brain injury

It is well known that the cognitive functions of juveniles recover to a greater extent than adult patients following traumatic brain injury (TBI). The exact mechanisms underlying this age-related disparity are unknown; however, we speculate that this improved recovery in juveniles following TBI may be associated with an endogenous neurogenic response in the hippocampus. We, therefore, examined the effects of TBI on cellular proliferation and differentiation in the dentate gyrus (DG) of the hippocampus in juvenile and adult rats following lateral fluid percussion injury (FPI). The temporal profile of the injury-induced proliferative response was determined using BrdU labeling at varying survival times. The differentiation of these newly generated cells was investigated using cell-type specific markers. We found that, following injury, there was a significant increase in cell proliferation in the DG in both injured juveniles and adults at 2 days post injury when compared to shams. When comparing the extent of cell proliferation between juveniles and adults following TBI, the absolute number of cells generated in the subgranular zone (SGZ) was far greater in the juveniles. Moreover, the percentage of newly generated cells in the SGZ that differentiated into neurons was nearly two times higher in the juveniles as compared to adults. Conversely, more glial differentiation was observed in the DG of adult rats. These findings provide compelling evidence that age-related differences in the neurogenic response to injury may underlie the differences observed in cognitive recovery in juvenile mammals as compared to adults following TBI.     

Proposal of a modified, treatment-oriented classification of odontoid fractures.

BACKGROUND CONTEXT: The classification scheme of odontoid fractures described by Anderson and D'Alonzo is the one most commonly used. However, uncertainty exists in the distinction between Type II and "shallow" Type III fractures. Moreover, fractures at the base of the odontoid (Anderson and D'Alonzo Type II) include a spectrum of injury patterns. PURPOSE: To modify the Anderson and D'Alonzo classification of odontoid fractures based on current clinical treatment options. STUDY DESIGN: Proposal of a modified classification system for odontoid fractures. METHODS: A more precise distinction between Type II and III fractures based on the presence/absence of C1-C2 facet involvement is proposed. A modified classification of Type II fractures based on fracture line obliquity, displacement and comminution is then proposed, because these are factors deemed to influence management. To evaluate the reproducibility of this classification, 52 odontoid fractures were reviewed and classified by four attending spine surgeons and three spine fellows. RESULTS: There was substantial agreement (at least five of seven respondents) in 70% of cases. The overall kappa value for the modified classification system was 0.48, indicating moderate agreement, and there were no differences in kappa values between attending spine surgeons and fellows. CONCLUSIONS: The reproducibility of this system was demonstrated by the moderate agreement observed when applied to odontoid fractures at our institution. The proposed utility of this system is its ability to guide clinical decision making in the treatment of odontoid fractures. Prospective application of this modified classification system and suggested treatment options is now required.     

pT2 classification for renal cell carcinoma. Can its accuracy be improved?

PURPOSE: The 2002 tumor classification for renal cell carcinoma (RCC) classifies pT2 tumors as more than 7 cm in greatest dimension, limited to the kidney. In this study we determined whether a size cutoff point exists within pT2 tumors and whether such subclassification would further improve the accuracy of the current tumor classification. MATERIALS AND METHODS: We studied 544 patients with unilateral, sporadic pT2 RCC treated with radical nephrectomy or nephron sparing surgery between 1970 and 2000. The association of tumor size with death from RCC was examined using martingale residuals from a Cox proportional hazards regression model to determine the optimal size cutoff point. RESULTS: There were 204 deaths from RCC a median of 3.8 years following nephrectomy. Univariately tumor size was significantly associated with death from RCC (risk ratio 1.08, 95% CI 1.04 to 1.13, p <0.001). A scatterplot of tumor size vs expected risk of death per patient suggested that a cutoff point between 9 and 10 cm was appropriate. When adjusted for regional lymph node involvement and distant metastases, the 10 cm cutoff point performed better than the 9 cm point (risk ratio 1.42, 95% CI 1.07 to 1.90, p = 0.017 vs 1.22, 95% 0.86 to 1.72, p = 0.268). Therefore, we propose using a 10 cm cutoff point to subclassify patients into pT2a and pT2b. CONCLUSIONS: Our data suggest that the prognostic accuracy of the 2002 pT2 tumor classification can be further improved by subclassifying patients with tumors greater than 7 and less than 10 cm into a pT2a category, and those with tumors 10 cm or greater into a pT2b category.