Biomedical subjects

David Zurakowski

Publications and source records attributed to David Zurakowski.

At least 109 records · Page 6Linked to original sources

PubMed2004

Emergency donor heart protection: application of the port access catheter technique using a pig heart transplantation model.

BACKGROUND: Organ shortage limits the number of transplantations, and donor deterioration may precede and often prevent conventional organ preservation. This study evaluates in situ perfusion as a bedside method for cardiac allograft procurement in a large animal model. METHODS: Thirty Landrace pigs (42 +/- 7 kg) were studied. The hearts in the conventional group underwent cardioplegic arrest with University of Wisconsin solution and sodium-hydrogen exchange inhibitor cariporide as an additive; they were explanted and stored on ice before transplantation. In the in situ group, one catheter was placed in the ascending aorta and another in the right atrium. After disconnection from the ventilator, hypoxia caused circulatory arrest. The aorta was endoclamped, and in situ perfusion of the aortic root was maintained with University of Wisconsin solution and cariporide. After explantation, hearts were stored on ice for 120 min. All hearts were implanted according to the Shumway technique. Ventricular pressure and cardiac output were monitored online, and troponin-I was measured intermittently. Two hours after weaning from extracorporal circulation, the animals were killed and histology was performed. RESULTS: Catheters were placed through introducers within 5 min. Functional recovery and histology were comparable between the two techniques. Troponin-I increased in both groups during reperfusion but at a faster rate in the in situ technique (P <0.01). CONCLUSION: In situ perfusion may be suitable for cardiac transplants when donor deterioration requires urgent organ preservation. Catheters can be placed at bedside and modified to achieve multi-organ protection through additional perfusion of the abdominal aorta.

Adenosine↗

PubMed2004

Spectroscopic and perfusion magnetic resonance imaging predictors of progression in pediatric brain tumors.

BACKGROUND: In vivo biomarkers to predict progression of brain tumors are of great value in clinical practice. Therefore, the authors tested the hypothesis that changes in choline ratios by magnetic resonance (MR) spectroscopic imaging and/or relative tumor blood volume (rTBV) can differentiate clinically stable from progressive pediatric brain tumors. METHODS: MR spectroscopic imaging examinations were performed on 27 children with neuroglial brain tumors during therapy on a 1.5-Tesla MR system. Normalized rTBV values were measured in 11 of 27 patients. Each examination was rated as stable or progressive by clinical and imaging criteria. RESULTS: The percent change in normalized choline (Cho) was significantly greater in patients who had progressive examinations compared with patients who had stable examinations (P = 0.03). The percent change in Cho/N-acetylaspartate (Cho/NAA) was significantly higher in patients who had progressive outcomes (n = 18 patients) compared with patients who had stable outcomes (n = 32 patients; P < 0.001; sensitivity, 0.89; specificity, 0.88) and was identified as the most important prognostic indicator of tumor progression by logistic regression (likelihood ratio test, 33.4; P < 0.001). The odds of tumor progression were approximately 55 times greater for patients who showed at least a 20% change in Cho/NAA. rTBV distinguished between progressing and stable tumors (P = 0.03), and Cho/NAA and rTBV values showed interaction to predict the probability of a progressing clinical outcome. CONCLUSIONS: The percent change in Cho/NAA by proton MR spectroscopic imaging, assisted by rTBV, was useful in predicting tumor progression in children with brain tumors.

Adolescent↗

PubMed2004

Effects of axonal injury on ganglion cell survival and glutamate homeostasis.

Axonal trauma leads to a series of pathologic events that can culminate in neuronal death. Optic nerve crush can be used to explore histologic and molecular changes in traumatic central nervous system malfunction. Although the precise mechanisms of retinal ganglion cell death after optic nerve crush have not been elucidated, glutamate antagonists can protect retinal ganglion cells after axotomy. We, therefore, evaluated the effect of optic nerve crush on levels of extracellular glutamate. Ganglion cell survival and extracellular glutamate levels were assessed from 1 to 28 days after optic nerve crush in Long-Evans rats. Optic nerve crush led to a rise in extracellular glutamate; this rise was blocked by treatment with memantine, riluzole, and nimodipine. Partial optic nerve crush leads to an increase in vitreal glutamate, perhaps through release of intracellular contents. This released glutamate can contribute to additional ganglion cell loss. Future work will help to additionally unravel the steps by which axotomy induces excitotoxic damage to ganglion cells, and perhaps indicate protective interventions.

Animals↗

PubMed2004

Overexpression of human fibroblast growth factor 2 stimulates cell proliferation in an ex vivo model of articular chondrocyte transplantation.

BACKGROUND: Genetically engineered chondrocytes could be used to enhance cartilage repair. Fibroblast growth factor 2 (FGF-2) is a mitogen for chondrocytes and may be a candidate for gene transfer approaches to stimulate chondrocyte proliferation. In the present study, we tested the hypothesis that human FGF-2 (hFGF-2) gene transfer into articular chondrocytes modulates cell proliferation in an ex vivo model of chondrocyte transplantation. METHODS: Transfection of articular chondrocytes with an expression plasmid vector carrying the cDNA for hFGF-2 under the control of the cytomegalovirus promoter/enhancer mediated transgene expression and synthesis of biologically relevant amounts of the recombinant hFGF-2 protein. Articular chondrocytes transfected with the Escherichia coli beta-galactosidase (lacZ) gene or a hFGF-2 cDNA were transplanted onto the surface of articular cartilage explants. RESULTS: The tissue formed by the chondrocytes expressing hFGF-2 was thicker and contained more cells than control cultures. Quantitative analysis of [(3)H]thymidine and [(35)S]sulfate incorporation in composite cultures revealed that hFGF-2 transfection stimulated mitogenic activity in the new tissue but did not augment matrix glycosaminoglycan synthesis. CONCLUSIONS: These data support the concept that chondrocytes overexpressing a hFGF-2 cDNA selectively modulate cell proliferation in an ex vivo model of chondrocyte transplantation. These results suggest that therapeutic hFGF-2 gene transfer may be applicable for the treatment of articular cartilage disorders, such as traumatic defects in which cellular repopulation is a therapeutic goal.

Animals↗

PubMed2004

CF: an X-ray database to assess effect of aerosolized tobramycin.

This paper assesses the effectiveness of aerosolized tobramycin (TOBI) on cystic fibrosis (CF) lung disease, using a radiologic tool. The published tool, the age-based severity curve (ABS), is derived from Brasfield scoring of chest X-rays (CXR). This study evaluates both the usefulness of the ABS as an assessment tool and the effectiveness of TOBI. Thirty-eight patients were treated with TOBI. Twenty-four treated with dornase alfa were excluded. Fourteen patients, aged 2 months to 22 years (mean, 17 months of TOBI treatment), comprised the study group. Radiographs were obtained over a mean of 7.8 years (SD = 6.5 years; range, 9 months-18 years). Two hundred and eighty-two CXR of TOBI patients were analyzed following the ABS protocol. Rate of decline in radiologic status of the TOBI group and ABS were compared. Also, TOBI was assessed by comparing rate of decline before and after initiation of treatment. The TOBI group's radiologic assessment was compared to its rate of decline in pulmonary function studies and published population data. Rate of decline in ABS was 0.175 Brasfield points/year vs. 0.150 points/year in the TOBI group (P < 0.001). Before treatment, the TOBI group's rate of decline was 0.169 Brasfield points/year; after treatment, it was 0.150 points/year (P = 0.02). Forced vital capacity revealed a statistically significant slowing in rate of decline on TOBI. Although not statistically significant, rate of decline in forced expiratory volume at 1 sec showed a similar trend. The degree of slowing in decline is similar to that previously reported for pulmonary function studies.

Administration, Inhalation↗

PubMed2004

Hemodilution elevates cerebral blood flow and oxygen metabolism during cardiopulmonary bypass in piglets.

BACKGROUND: Hemodilution continues to be widely used during cardiopulmonary bypass (CPB) for both adults and children. Previous studies with nonbypass models have suggested that an increase in cerebral blood flow (CBF) compensates for the reduced oxygen-carrying capacity; however, this increased CBF is achieved by an increase in cardiac output. We hypothesized that even with the fixed-flow perfusion of CPB, CBF would be increased during hemodilution. METHODS: Two experiments were conducted and analyzed separately. In each experiment, 10 piglets were randomized to two different groups, one with a total blood prime yielding a high hematocrit (25% or 30%), and the other with a crystalloid prime resulting in a low hematocrit (10% or 15%). Animals were cooled with pH-stat strategy at full flow (100 or 150 mL.kg(-1).min(-1)) to a nasopharyngeal temperature of 15 degrees C, a period of low flow (50 mL.kg(-1).min(-1)) preceding deep hypothermic circulatory arrest (45 or 60 minutes), and a period of rewarming at full flow. Cerebral blood flow was measured at the beginning of CPB, at the end of cooling, at the end of low flow, 5 minutes after the start of rewarming, and at the end of rewarming by injection of radioactive microspheres. RESULTS: Mean arterial pressure was significantly greater with higher hematocrit at each time point (p< 0.05). Cerebral blood flow and the cerebral metabolic rate of oxygen decreased during cooling and further during low flow bypass but were significantly greater with lower hematocrit during mild hypothermia and at the end of rewarming (p< 0.05). CONCLUSIONS: Hemodilution is associated with decreased perfusion pressure, increased CBF and increased the cerebral metabolic rate of oxygen during hypothermic CPB.

Animals↗

PubMed2004

Interobserver and intraobserver reliability of therapist-assisted videotaped evaluations of upper-limb hemiplegia.

PURPOSE: Therapist-assisted videotaped sessions have been used to augment physical examinations in the evaluation of hand and arm function in patients with spastic hemiplegia. The purpose of this study was to assess the interobserver and intraobserver reliability of standardized videotaped examinations in the evaluation and functional classification of these patients. METHODS: Three examiners reviewed standardized videotaped examinations of 10 adolescents with spastic hemiplegia on 2 separate occasions. All 10 patients were under consideration for surgical intervention for their upper-extremity dysfunction. Videotapes were used to assess upper-extremity range of motion, finger and thumb deformity, and reach, pinch, and grip function. Upper-extremity function was graded according to the House and Mowery classification systems. Interobserver and intraobserver reliabilities were measured with the kappa coefficient. RESULTS: Range of motion, deformity, and upper-extremity functional strategy assessment showed slight to excellent interobserver reliability and good to almost perfect intraobserver reliability. Interobserver and intraobserver reliability of the consolidated House classification system was more reliable than the Mowery or standard House classification systems. CONCLUSIONS: Evaluations of standardized videotaped examinations in patients with hemiplegia were reliable between and among observers. Such therapist-assisted videotaped evaluations may provide useful data for clinical decision-making and multicenter outcomes studies in patients with upper-extremity involvement with spastic hemiplegia.

Adolescent↗

PubMed2004

Interaction of temperature with hematocrit level and pH determines safe duration of hypothermic circulatory arrest.

OBJECTIVE: Previous studies have demonstrated that both hematocrit level and pH influence the protection afforded by deep hypothermic circulatory arrest. The current study examines how temperature modulates the effect of hematocrit level and pH in determining a safe duration of circulatory arrest. The study also builds on previous work investigating the utility of near-infrared spectroscopy as a real-time monitor of cerebral protection during circulatory arrest. METHODS: Seventy-six piglets (9.3 +/- 1.2 kg) underwent circulatory arrest under varying conditions with continuous monitoring by means of near-infrared spectroscopy (hematocrit level of 20% or 30%; pH-stat or alpha-stat strategy; temperature of 15 degrees C or 25 degrees C; arrest time of 60, 80, or 100 minutes). Neurologic recovery was evaluated daily by a veterinarian, and the brain was fixed in situ on postoperative day 4 to be examined on the basis of histologic score in a blinded fashion. RESULTS: Multivariable analysis of total histologic score revealed that higher temperature, lower hematocrit level, more alkaline pH, and longer hypothermic circulatory arrest duration were predictive of more severe damage to the brain (P <.01). Regression modeling revealed that higher temperature exacerbated the disadvantage of a lower hematocrit level and longer arrest times but not pH strategy. Normalized oxyhemoglobin nadir time, derived from near-infrared spectroscopy, was positively correlated with neurologic recovery on the fourth postoperative day and with total histologic injury score (P <.0001). CONCLUSION: Hematocrit level and pH, as well as temperature, determine the safe duration of hypothermic circulatory arrest. Near-infrared spectroscopy is a useful real-time monitor of safe duration of circulatory arrest.

Animals↗

PubMed2004

Higher bypass temperature correlates with increased white cell activation in the cerebral microcirculation.

OBJECTIVE: Cardiopulmonary bypass induces a systemic inflammatory response, which in turn promotes a cascade of leukocyte and endothelial cell activity. We investigated whether differences in bypass temperature and flow rate affect endothelial cell and leukocyte adhesion in the cerebral microcirculation. METHODS: Thirty-six piglets (13.0 +/- 1.1 kg) had a cranial window placed over the parietal cortex to evaluate the microcirculation by means of intravital microscopy. Animals were cooled to a temperature of 15 degrees C, 25 degrees C, or 34 degrees C on cardiopulmonary bypass with hematocrit levels of 20% or 30% by using pH-stat management, followed by 60 minutes of reduced flow (10, 25, or 50 mL.kg(-1).min(-1)). Rhodamine staining was used to observe adherent and rolling leukocytes in postcapillary venules. RESULTS: Higher bypass temperature correlated with significantly more adherent and rolling leukocytes during the full 60 minutes of low-flow bypass (P <.05). Poisson regression revealed more adherent leukocytes at 34 degrees C than at 15 degrees C and at a flow rate of 10 mL.kg(-1).min(-1) compared with a flow rate of 50 mL.kg(-1).min(-1). There was an inverse correlation between flow rate and the number of adherent and rolling leukocytes at 30, 45, and 60 minutes of low-flow bypass (P <.05). Temperature was a multivariable predictor of histologic score, with greater neurologic damage found after bypass at 34 degrees C (P <.01). CONCLUSIONS: Leukocyte activation in cerebral microcirculation is increased with higher temperature and lower flow rate, suggesting that these variables influence the inflammatory response during cardiopulmonary bypass.

Animals↗

PubMed2004

Malignant fibrous histiocytoma of the extremities and trunk: an institutional review.

BACKGROUND: Malignant fibrous histiocytoma (MFH) is the most common subtype of soft-tissue sarcoma. Detailed understanding of this tumor type may lead to improved therapeutic strategies. METHODS: An institutional review was performed on all patients with primary MFH of the extremities and trunk operated on between 1988 and 2000. RESULTS: Ninety-seven patients with histologically confirmed MFH (G1, n=8; G2, n=25; G3, n=64) were analyzed. Local recurrence was 31% after a median of 13 months. Distant metastases occurred in 29 patients (30%). After a median follow-up of 4.5 years, 54 patients were alive without evidence of disease; median survival time was 84 months at a cumulative 5-year survival rate of 70%. Tumor size significantly influenced disease-free survival (T2 vs T1, P<.01, risk ratio [RR] 6.0), as did tumor depth (subfascial tumors, P<.01, RR 3.1) and presence of positive lymph nodes (P=.02, RR 6.9). Positive microscopic margins and subfascial tumors were associated with an increased local recurrence rate (RR 4.8, P<.001 and RR 3.5, P=.02, respectively). Significant multivariate risk factors of distant metastases were tumor size, depth, and grade. Though not performed in a randomized fashion, a subgroup analysis indicated that adjuvant radiation therapy significantly reduced local tumor failure. CONCLUSION: We conclude that aggressive, albeit limb-preserving resection of MFH, should be performed at initial operation to minimize risk of local recurrence; a strict follow-up especially of subfascial tumors should be performed.

Abdominal Neoplasms↗

PubMed2004

Glenoid version and rotator cuff tears.

The purpose of this study was to determine the relationship between rotator cuff (RC) tear and the orientation of the glenoid. Ninety-six shoulders (94 patients) that underwent open RC repair were grouped according to the type of tear. We measured on MRI the acromio-glenoid angle (AG) and the supraspinatus fossa glenoid angle on the anterior-posterior (SGAP) and axial (SGAX) views. RC patients had a smaller AG angle (76+/-7 degrees vs. 86+/-10 degrees ) and a larger SGAP angle (112+/-6 degrees vs. 102+/-7 degrees ) compared to controls (p<0.001). We also found a highly significant difference (p<0.001) in glenoid version measured by SGAX between anterior cuff tears (-5+/-4 degrees ) and posterior cuff tears (3+/-3 degrees ). Furthermore, we identified an association between RC tear and the orientation of the glenoid relative to the axis of the supraspinatus fossa. Greater retroversion is predictive of an anterior cuff injury and greater anteversion is predictive of a posterior cuff injury.

Humans↗

PubMed2004

Effects of hemodilution and phenylephrine on cerebral blood flow and metabolism during cardiopulmonary bypass.

OBJECTIVE: Hypotension resulting from hemodilution on cardiopulmonary bypass is often treated by pressor (eg, phenylephrine) infusion. The effect of phenylephrine on cerebral blood flow (CBF) in this setting is not clear. It was hypothesized that phenylephrine might decrease CBF. MEASUREMENTS AND MAIN RESULTS: Six different radioactively labeled microspheres (15 microm) were used to measure CBF at 6 time points (T) in 9 pigs (mean body weight 11.3 +/- 1.2 kg): T1 baseline before bypass (mean arterial pressure [MAP] 76 +/- 5 mmHg), T2 on mildly hypothermic CPB (34 degrees C, pump flow 100 mL/kg/min, hematocrit 30%, MAP 79 +/- 7 mmHg), T3 after moderate hemodilution with crystalloid (hematocrit 20%, resulting MAP 62 +/- 6 mmHg), T4 after phenylephrine administration to increase MAP to baseline values (hematocrit 20%), T5 after severe hemodilution (hematocrit 10%, resulting MAP 41 +/- 4 mmHg), and T6 after phenylephrine administration to normalize MAP (hematocrit 10%). In addition, blood flow to liver, small bowel and skeletal muscle, and pH of jugular venous blood were measured at each time point. After institution of CPB, the CBF (mL/min/100 g tissue) increased significantly to 53 +/- 9 (baseline levels 44 +/- 8, T1 v T2, p = 0.03). Hemodilution resulted in significant increases in CBF on CPB to 65 +/- 9 and 90 +/- 9 at hematocrit 20% and hematocrit 10%, respectively (T2 v T3, p = 0.03; T3 v T5, p = 0.01) and a progressive fall in jugular venous pH. At each level of hemodilution, phenylephrine resulted in an additional increase in CBF (T4, 74 +/- 8; T6, 108 +/- 12; T3 v T4, p = 0.04; T5 v T6, p = 0.01) but did not improve jugular venous pH. Changes in liver blood flow after hemodilution and vasopressor injection showed a similar pattern to CBF. However, the blood flow to small bowel and skeletal muscle increased with hemodilution but decreased significantly with phenylephrine administration. CONCLUSIONS: Phenylephrine redirects blood flow from the bowel and muscle to the brain and liver. Hemodilution increases CBF and pressor administration further increases CBF by elevating perfusion pressure. Maintenance of a higher hematocrit on CPB increases MAP and should decrease the need for vasopressor administration.

Animals↗

PubMed2004

Adeno-associated viruses containing bFGF or BDNF are neuroprotective against excitotoxicity.

PURPOSE: Brain-derived neurotrophic factor (BDNF) and basic fibroblast growth factor (bFGF) hold much promise for the protection of retinal ganglion cells against excitotoxic cell death. We tested the possibility of delivering these growth factors to retinal ganglion cells via an adeno-associated viral (AAV) vector and tested their efficacy in two models of excitotoxicity. METHODS: Rat retinas were infected with AAV vectors encoding bFGF or BDNF. A control vector containing green fluorescent protein (GFP) was injected in the contralateral eye. Eyes were subjected to either an intravitreal injection of N-methyl-D-aspartate (NMDA) or optic nerve crush, and ganglion cell survival was evaluated. RESULTS: AAV.CMV.bFGF and AAV.CBA.BDNF were neuroprotective against NMDA injection 1 month post-treatment. Additionally, AAV.CMV.bFGF was protective against optic nerve crush. CONCLUSION: AAV-mediated delivery of bFGF and BDNF can promote retinal cell survival following excitotoxic insult.

Animals↗

PubMed2004

Is adolescent varicocele a progressive disease process?

PURPOSE: We determined whether there was evidence of progression in either varicocele grade or testicular volume differentials over time in our adolescent varicocele population. MATERIALS AND METHODS: A total of 41 boys 7.3 to 19 years old (mean age 13.7, SD 2.5) were seen at sequential visits. At each visit varicocele grade was determined by the attending urologist and ultrasound calculated testicular volume differential was determined by an attending ultrasonographer. A senior staff statistician performed statistical analysis of the sequential data. RESULTS: The varicocele grade data were analyzed using the nonparametric Wilcoxon test and no significant evidence of progression on sequential visits was demonstrated. Similarly, the serial volume differential data were assessed using the paired t test and no significant evidence for progression of testicular volume differentials was demonstrated. CONCLUSIONS: In our study population neither varicocele grade nor change in testicular volume differentials increased over time in a statistically significant manner. These results argue against the concept that adolescent varicocele is a progressive disease process.

Adolescent↗

PubMed2004

The death of articular chondrocytes after intra-articular fracture in humans.

BACKGROUND: In this study, we wished to determine whether chondrocyte death occurs after intra-articular fracture and might thus contribute to the development of posttraumatic arthritis. METHODS: Articular fracture fragments were obtained from 30 patients and the terminal deoxynucleotide transferase-mediated dUTP nick-end labeling assay was used to identify dead or dying cells. RESULTS: Dead or dying cells were identified in all fracture fragments, with an average rate of cell death of 35%. Rates of cell death greater than 90% were seen in 4 of the 30 specimens studied. CONCLUSION: Although rates of apoptosis in osteoarthritis have been reported to average 15%, the rate in this fracture population was more than twice this value (35%). The high rate of cell death noted here may help explain the occurrence of posttraumatic arthritis even in anatomically fixed intra-articular fractures.

Adult↗

PubMed2004

Serologic testing with ANCA, ASCA, and anti-OmpC in children and young adults with Crohn's disease and ulcerative colitis: diagnostic value and correlation with disease phenotype.

OBJECTIVES: Serologic testing is increasingly being utilized to evaluate children with suspected inflammatory bowel disease (IBD). The aim of this paper was to evaluate the sensitivity and specificity of a currently available panel involving four antibodies: deoxyribonuclease (DNase)-sensitive perinuclear antineutrophil cytoplasmic antibody (DNase-sensitive pANCA), IgA and IgG antibodies to Saccharomyces cerevisiae (IgA and IgG ASCA), and antibody to Escherichia coli outer membrane porin (anti-OmpC). We also wished to determine whether antibody levels correlated with disease activity, and whether a specific antibody pattern correlated with location and outcome of disease in children. METHODS: We studied sera from 81 children with Crohn's disease (CD), 54 with ulcerative colitis (UC), and 63 controls. Clinical data, disease activity, and disease diagnosis were gathered at the time of serum sampling, and charts were re-reviewed at time of the study to determine long-term outcome. Enzyme-linked immunosorbent assay was utilized to determine titers of antibodies to ASCA, DNase-sensitive pANCA, and anti-OmpC; the presence of perinuclear staining for ANCA was confirmed by immunofluorescence. RESULTS: We identified ASCA antibodies in 44% of CD patients, 0% of UC patients, and 1 control patient. DNase-sensitive pANCA antibodies were found in 70% of patients with UC, 18% of CD patients (predominantly Crohn's colitis), and 3% of controls. Anti-OmpC as an isolated assay had low sensitivity for both CD (24%) and UC (11%), and displayed a 5% false-positive rate. However, anti-OmpC did identify a small number of IBD patients not detected by the other assays. If any one or more of the four antibodies was positive, the overall sensitivity of the four antibody panel was 65% for CD and 76% for UC, with a specificity of 94%. Patients who were ASCA-positive were more likely to have disease of the ileum or ileum and right colon than patients who were ASCA-negative (58%vs 18%, p < 0.001). Patients with ASCA-positive were also more likely to require ileocecal resection (36%vs 13%, p < 0.05). CONCLUSIONS: A currently available commercial antibody panel has good sensitivity and excellent specificity for CD and UC. The ASCA antibodies, while highly specific for CD, identify predominantly the subset of children with disease of the ileum and ascending colon who may be at increased risk of surgery.

Adolescent↗

PubMed2004

Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children.

BACKGROUND: The differentiation between septic arthritis and transient synovitis of the hip in children can be difficult. The purpose of the present study was to validate a previously published clinical prediction rule for this differentiation in a new patient population. METHODS: We prospectively studied children who presented to a major children's hospital between 1997 and 2002 with an acutely irritable hip. As in the previous study, diagnoses of septic arthritis (fifty-one patients) and transient synovitis (103 patients) were operationally defined on the basis of the white blood-cell count in the joint fluid, the results of cultures of joint fluid and blood, and the clinical course. Univariate analysis and multiple logistic regression were used to compare the two groups. The predicted probability of septic arthritis of the hip from the prediction rule was compared with actual distributions in the current patient population. The area under the receiver operating characteristic curve was determined. RESULTS: The same four independent predictors of septic arthritis of the hip (a history of fever, non-weight-bearing, an erythrocyte sedimentation rate of 40 mm/hr, and a serum white blood-cell count of >12,000 cells/mm(3) (>12.0 x 10(9)/L)) were identified in the current patient population. The predicted probability of septic arthritis of the hip from the prediction rule was similar to the actual distributions in the current patient population. The area under the receiver operating characteristic curve for the current patient population was 0.86, compared with 0.96 in the original population. CONCLUSIONS: Clinical prediction rules typically demonstrate diminished performance in a new patient population because they are optimally modeled to the original data set. The previously published clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children demonstrated diminished, but nevertheless very good, diagnostic performance in a new patient population.

Algorithms↗

PubMed2004

Infantile hepatic hemangiomas: clinical and imaging findings and their correlation with therapy.

OBJECTIVE: This study was undertaken to determine different imaging patterns in infantile hepatic hemangiomas and to explore the relationship between clinical presentations, imaging findings, and response to therapy. MATERIALS AND METHODS: The imaging studies and clinical records of all patients with infantile hepatic hemangiomas from two tertiary children's hospitals were reviewed. Univariate and multivariate stepwise logistic regression techniques were used to determine whether clinical presentation and imaging variables differentiated the type of treatment required. RESULTS: Typical hemangiomas appeared as focal or multifocal T2-hyperintense spheres with centripetal contrast enhancement and dilated feeding and draining vessels. Three atypical patterns included focal mass lesions with central varix with or without direct shunts, focal mass with central necrosis or thrombosis, and massive hemangiomatous involvement of the liver with abdominal vascular compression. In general, patients with focal lesions without high flow needed no treatment, and those with central varix and direct shunts developed severe high-output cardiac failure that responded quickly to embolization. The pattern of massive replacement of liver was associated with hypothyroidism, abdominal compartment syndrome, and a high mortality rate. Multivariate analysis of 55 patients indicated that congestive heart failure was the only independent predictor of treatment (p = 0.005). The presence of a shunt was the only independent factor associated with embolization or surgery (p = 0.002). CONCLUSION: Although the imaging features of infantile hepatic hemangiomas vary to some extent, MRI features are typical in most patients and certain imaging findings are predictive of the clinical course. MRI is the technique of choice in diagnosing infantile hepatic masses.

Chi-Square Distribution↗