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Biomedical subjects

David Zurakowski

Publications and source records attributed to David Zurakowski.

At least 91 records · Page 5Linked to original sources
PubMed2005

Integron-associated antibiotic resistance and phylogenetic grouping of Escherichia coli isolates from healthy subjects free of recent antibiotic exposure.

The study of integrons in 181 Escherichia coli isolates from three groups of healthy subjects who lived in communities and had not taken antibiotics for at least 1 month showed that the presence of integrons was associated with antibiotic resistance and phylogenetic grouping of the bacterial host and dependent on a subject's living environment.

Anti-Bacterial Agents↗
PubMed2005

Adverse cardiovascular and respiratory events during sedation of pediatric patients for imaging examinations.

PURPOSE: To retrospectively identify factors associated with an increased risk of adverse cardiovascular or respiratory events during sedation of pediatric patients for imaging examinations. MATERIALS AND METHODS: This HIPAA-compliant study was institutional review board approved; the requirement for informed consent was waived. All sedation information--including patient demographics, medications (doses and routes of administration), time required to sedate and before discharge, American Society of Anesthesiologists physical status classification, adverse events, and failed sedations--was maintained in a computerized database. A review of the data on all patients sedated between 1997 and 2003 for magnetic resonance imaging, computed tomography, and interventional radiology revealed associated adverse respiratory events in 70 patients. Adverse respiratory event was defined as oxygen desaturation of at least 5%, pulmonary aspiration, and need for airway resuscitation. Adverse cardiovascular events were defined as cardiac arrest and hemodynamic changes requiring medical therapy. Adverse events were compared between sedation regimens--which included fentanyl, chloral hydrate, pentobarbital, and midazolam hydrochloride--by using the Fisher exact test. Multiple logistic regression analysis was applied to identify potential predictors of adverse events. RESULTS: Among 16,467 sedations performed, 70 (0.4%) were associated with adverse respiratory events: 58 cases of oxygen desaturation, two pulmonary aspirations, 10 cases of airway resuscitation, and no cardiovascular events. Nearly 30% (n = 20) of the 70 patients who had an adverse event had a history of serious respiratory illness. Logistic regression analysis revealed that neither patient age, weight, or sex nor type of imaging procedure was associated with an increased risk of an adverse event. Use of a single sedation agent was associated with lower adverse event risk than was use of multiple agents (P < .001). CONCLUSION: Consideration should be given to using single agents, avoiding the use of multidrug sedation regimens, and recognizing that a history of pulmonary disease could be associated with an increased risk of adverse respiratory events despite a currently stable respiratory state.

Cardiovascular System↗
PubMed2005

A comparison of the Vasotrac with invasive arterial blood pressure monitoring in children after pediatric cardiac surgery.

The Vasotrac is a device that provides near-continuous and noninvasive arterial blood pressure monitoring and may be an alternative to direct intraarterial measurement. It has been evaluated in adult patients, but minimal information is available for pediatric patients. We evaluated agreement between measurements of arterial blood pressure and heart rate obtained from the Vasotrac versus an arterial catheter in a pediatric population. Children undergoing corrective cardiac surgery were enrolled. Simultaneous arterial blood pressure measurements were obtained postoperatively from the Vasotrac unit and an arterial catheter. Bland-Altman plots were constructed to assess agreement. Paired correlation analysis, bias, and precision calculations were performed. Sixteen patients, mean age 10.1 +/- 2.3 yr and weight 34.6 +/- 11.9 kg, were enrolled. Four-thousand-one- hundred- two paired measurements were obtained. Arterial blood pressures measured noninvasively correlated with catheter measurements with Pearson r values of 0.90, 0.80, and 0.91 for systolic, diastolic, and mean arterial blood pressures, respectively (all P < 0.001). There was excellent agreement between arterial blood pressure measurement methods. Absolute mean differences based on mixed-model regression with 95% confidence intervals were 4.0 mm Hg (3.0-5.0 mm Hg), 4.3 mm Hg (3.1-5.5 mm Hg), and 3.5 mm Hg (2.5-4.0 mm Hg) for systolic blood pressure, diastolic blood pressure, and mean blood pressure, respectively. Arterial blood pressure measurements obtained from the Vasotrac agreed well with invasive arterial monitoring in pediatric patients.

Adolescent↗
PubMed2005

Hemodynamic responses to etomidate on induction of anesthesia in pediatric patients.

Etomidate is often used for inducing anesthesia in patients who have limited hemodynamic reserve. Using invasive hemodynamic monitoring, we studied the acute effects of a bolus of etomidate during induction of anesthesia in children. Twelve children undergoing cardiac catheterization were studied (mean age, 9.2 +/- 4.8 yr; mean weight, 33.4 +/- 15.4 kg); catheterization procedures included device closure of secundum atrial septal defects (n = 7) and radiofrequency catheter ablation procedures for supraventricular tachycardia (n = 5). Using IV sedation, a balloon-tipped pulmonary artery catheter was placed to measure intracardiac and pulmonary artery pressures and oxygen saturations. Baseline measurements were recorded and then repeated after a bolus of IV etomidate (0.3 mg/kg). For the entire group, no significant changes in right atrial, aortic, or pulmonary artery pressure, oxygen saturations, calculated Qp:Qs ratio or systemic or pulmonary vascular resistance were detected after the bolus dose of etomidate. The lack of clinically significant hemodynamic changes after etomidate administration supports the clinical impression that etomidate is safe in children. Further research is needed to determine the hemodynamic profile of etomidate in neonates and in pediatric patients with severe ventricular dysfunction and pulmonary hypertension.

Adolescent↗
PubMed2005

A comparison of radial artery blood pressure determination between the Vasotrac device and invasive arterial blood pressure monitoring in adolescents undergoing scoliosis surgery.

UNLABELLED: The Vasotrac device (Medwave, Arden Hills, MN) allows noninvasive measurement of arterial blood pressure (BP) and arterial waveform. We have previously demonstrated agreement between the Vasotrac and continuous intraarterial BP monitoring in children with a stable circulation after cardiac surgery in the cardiac intensive care unit. To assess this monitor during different physiologic conditions, we studied the Vasotrac in anesthetized adolescent children undergoing scoliosis surgery in the prone position, with or without controlled hypotension. Eleven children undergoing surgery for idiopathic scoliosis were enrolled in this study. The anesthetic consisted of primarily a nitrous oxide and narcotic technique with controlled hypotension obtained using IV labetalol. Data were analyzed using correlations, mean error, and Bland-Altman plots. Noninvasive BP measured by the Vasotrac correlated closely with intraarterial BP. Waveforms displayed by the two systems were qualitatively similar. Correlation between the two methods for systolic, diastolic and mean BP was r = 0.82, r = 0.83, and r = 0.90, respectively. We conclude that noninvasive BP measurement using the Vasotrac monitor enables near-continuous and reliable monitoring of BP during anesthesia in the prone position and pharmacologic-induced hypotension. IMPLICATIONS: The Vasotrac, a noninvasive arterial blood pressure monitor, performs well in the prone position in adolescent patients undergoing scoliosis surgery using a technique of mild-to-moderate induced hypotension.

Adolescent↗
PubMed2005

Increased expression of urinary matrix metalloproteinases parallels the extent and activity of vascular anomalies.

OBJECTIVE: Matrix metalloproteinases (MMPs) and the angiogenic proteins basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have been implicated in mechanisms of human cancer and metastasis. Assays were conducted on the urine of patients with vascular anomalies (tumors and malformations), relatively common and occasionally life-threatening disorders for which few therapies exist. We sought to determine whether these angiogenesis modulators are present in the urine and whether their expression is associated with the extent and clinical course of the vascular lesion. METHODS: A total of 217 patients with vascular anomalies and 74 age-matched control subjects participated. Urinary MMP expression was determined by substrate gel electrophoresis. Urinary bFGF and VEGF levels were measured by enzyme-linked immunosorbent assay. Each patient was assigned to 1 of 2 categories (tumor or malformation) and 1 of 9 specific groups. Extent of the vascular lesion and activity were scored by a blinded clinician. RESULTS: Urinary high molecular weight (hMW) MMPs and bFGF were significantly increased in patients with vascular tumors (53%) and vascular malformations (41%), compared with control subjects (22%). These percentages increased as a function of extent of the lesion and disease activity. hMW MMPs were increased in 4 groups: infantile hemangioma, other vascular neoplasms, lymphatic malformation and capillary-lymphaticovenous malformations, and extensive and unremitting capillary malformation and arteriovenous malformation. No significant differences among the groups were detected for low molecular weight MMPs or VEGF. CONCLUSIONS: Expression patterns of hMW MMPs and bFGF in the urine of patients with tumors and malformations are consistent with their different clinical behavior. These data represent the first evidence that MMPs are elevated in the urine of children with vascular anomalies. These data also suggest that the increased expression of urinary MMPs parallels the extent and activity of vascular anomalies in children. In addition to tumors, vascular malformations are angiogenesis dependent, suggesting that progression of a vascular malformation might be suppressed by angiogenic inhibitors, which would target bFGF and MMPs.

Adolescent↗
PubMed2005

Uncemented glenoid component in total shoulder arthroplasty. Survivorship and outcomes.

BACKGROUND: Glenoid component loosening continues to be a major factor affecting the long-term survivorship of total shoulder replacements. Radiolucent lines, cement fracture, migration, and loosening requiring revision are common problems with cemented glenoid components. The purpose of this study was to evaluate the results of total shoulder arthroplasty with an uncemented glenoid component and to identify predictors of glenoid component failure. METHODS: One hundred and forty-seven consecutive total shoulder arthroplasties were performed in 132 patients (mean age, 63.3 years) with use of an uncemented glenoid component fixed with screws between 1988 and 1996. One hundred and forty shoulders in 124 patients were available for follow-up at an average of 7.5 years. One shoulder in which the arthroplasty had failed at 2.4 years and for which the duration of follow-up was four years was also included for completeness. The preoperative diagnoses included osteoarthritis in seventy-two shoulders and rheumatoid arthritis in fifty-five. RESULTS: Radiolucency was noted around the glenoid component and/or screws in fifty-three of the 140 shoulders. The mean modified ASES (American Shoulder and Elbow Surgeons) score (and standard deviation) improved from 15.6 +/- 11.8 points preoperatively to 75.8 +/- 17.5 points at the time of follow-up. Eighty-five shoulders were not painful, forty-two were slightly or mildly painful, ten were moderately painful, and three were severely painful. Fifteen (11%) of the glenoid components failed clinically, and ten of them also had radiographic signs of failure. Eleven other shoulders had radiographic signs of failure but no symptoms at the time of writing. Three factors had a significant independent association with clinical failure: male gender (p = 0.02), pain (p < 0.01), and radiolucency adjacent to the flat tray (p < 0.001). In addition, the annual risk of implant revision was nearly seven times higher for patients with radiographic signs of failure. Clinical survivorship was 95% at five years and 85% at ten years. CONCLUSIONS: The failure rates of the total shoulder arthroplasties in this study were higher than those in previously reported studies of cemented polyethylene components with similar durations of follow-up. Screw breakage and excessive polyethylene wear were common problems that may lead to additional failures of these uncemented glenoid components in the future.

Adult↗
PubMed2005

Preoperative skin preparation of the foot and ankle: bristles and alcohol are better.

BACKGROUND: The most efficient way to prepare the skin for foot and ankle surgery is unknown. In recent studies, >70% of aerobic bacterial cultures of specimens taken from the nail folds following skin preparation with povidone-iodine were positive. The goal of the current study was to determine the effect of isopropyl alcohol on the eradication of bacteria from the nails and skin of the normal foot and ankle. In addition, the effect of using a bristled brush rather than sponges to scrub the foot was investigated. METHODS: Four skin-preparation techniques were studied in two sets of twenty-five volunteers. In phase I of the study, the right foot and ankle of each member of the first set of volunteers was prepared with method 1, which consisted of a two-stage povidone-iodine scrub and paint with use of soft sponges. The left foot and ankle was prepared with method 2, which consisted of method 1 as well as an additional pre-wash with 70% isopropyl alcohol. In phase II, the right foot and ankle of each member of the second set of volunteers was prepared with method 3, which consisted of a povidone-iodine scrub and paint with use of a bristled brush to scrub the foot. The left side was prepared with method 4, which consisted of an alcohol scrub and paint with use of a bristled brush to scrub the foot. At the end of the preparation process, specimens for aerobic bacterial cultures were obtained from the hallucal nail fold, interdigital web spaces, and anterior aspect of the ankle. Cultures were interpreted as positive or negative, and the results were also assessed quantitatively. RESULTS: The rates of positive cultures of the nail-fold specimens were 76% and 80% after methods 1 and 2 (soft sponges) and 76% and 12% after methods 3 and 4 (bristled brush). The reduction in the percentage of positive cultures with method 4 was highly significant (p < 0.001). Cultures of the specimens from the web spaces showed a significant difference in the rates of positive results between methods 1 and 2 (36% and 8%, p < 0.05) but no significant difference between methods 3 and 4 (12% and 0%, p = 0.25). The rates of positive cultures of specimens from the anterior aspect of the ankle were consistently low (< or = 4% for all methods). Quantitative analysis of positive cultures demonstrated significant reductions (p < 0.01) in heavy growth when bristled brushes had been used, both with povidone-iodine and isopropyl alcohol. CONCLUSIONS: The use of isopropyl alcohol and the use of a bristled brush both have beneficial effects on the skin-preparation process before foot and ankle surgery. In the current investigation, the most effective technique was the use of isopropyl alcohol in conjunction with scrubbing with a bristled brush. Merely washing the foot with alcohol-soaked sponges provided limited benefit to the web spaces only.

2-Propanol↗
PubMed2005

Pain dominates measurements of elbow function and health status.

BACKGROUND: Elbow function can be quantified with use of physician-based elbow-rating systems and health status questionnaires. Our hypothesis was that pain has a strong influence on these scores, which overwhelms the influence of objective factors such as motion. METHODS: One hundred and four patients were evaluated, at a minimum of six months (average, forty-six months) after the latest surgery for an intra-articular fracture of the elbow, with use of three physician-based evaluation instruments (Mayo Elbow Performance Index [MEPI], Broberg and Morrey rating system, and American Shoulder and Elbow Surgeons Elbow Evaluation Instrument [ASES]), an upper-extremity-specific health status questionnaire (Disabilities of the Arm, Shoulder and Hand [DASH]), and a general health status questionnaire (Short Form-36 [SF-36]). Multivariate analysis of variance and regression modeling were used to identify the factors that account for the variability in scores derived with these measures-in other words, which factors have the strongest influence on the final score. RESULTS: Pain alone accounted for 66% of the variability in the MEPI scores, 59% of the variability in the Broberg and Morrey scores, and 57% of the variability in the ASES scores. Models that included other factors accounted for only slightly more variability (73%, 79%, and 79%, respectively), and those that did not include pain accounted for only 22%, 41%, and 41% of the variability. Thirty-six percent of the variability in the DASH scores could be accounted for by pain alone, and 45% could be accounted for by pain and range of motion. Models not including pain accounted for only 17% of the variability in the DASH scores. CONCLUSIONS: Pain has a very strong influence on both physician-rated and patient-rated quantitative measures of elbow function. Consequently, these measures may be strongly influenced by the psychosocial aspects of illness that have a strong relationship with pain, and objective measures of elbow function such as mobility may be undervalued. It may be advisable to evaluate pain separately from objective measures of elbow function in physician-based elbow ratings.

Adult↗
PubMed2005

Prevalence of osteoarthrosis of the trapeziometacarpal joint.

BACKGROUND: The age and gender-related prevalence of arthrosis of the trapeziometacarpal joint has been incompletely defined. METHODS: The radiographs of 615 consecutive patients who had presented with an isolated fracture of the distal part of the radius over a two-year period were evaluated for evidence of trapeziometacarpal arthrosis. We used a simple three-grade rating system suitable for standard wrist radiographs. Grade I indicated no or nearly no arthrosis; grade II, obvious arthrosis; and grade III, a totally destroyed joint. This rating system was demonstrated to have adequate intraobserver reliability (average kappa of 0.72, p < 0.001) and interobserver reliability (average kappa of 0.56, p < 0.001). The number of patients with each grade of arthrosis was analyzed according to age and gender. RESULTS: The overall radiographic prevalence of trapeziometacarpal arthrosis in patients with a distal radial fracture increased steadily from the age of forty-one years onward and reached a prevalence of 91% in patients older than eighty years of age. The prevalence increased more rapidly in women than in men; it reached 94% in women who were older than eighty years of age compared with 85% in men who were older than eighty years of age. The prevalence of grade-III trapeziometacarpal arthrosis (a totally destroyed joint) was much greater in women than in men at all age levels; it reached a prevalence of 66% in women older than eighty years of age compared with 23% in men older than eighty years of age. CONCLUSIONS: The radiographic prevalence of trapeziometacarpal arthrosis in patients presenting for treatment of a distal radial fracture is age-related, and trapeziometacarpal arthrosis is more likely to lead to complete joint destruction in women than it is in men.

Adolescent↗
PubMed2005

MRI features of Lyme arthritis in children.

OBJECTIVE: Oligoarthritis is the most common manifestation of late Lyme disease in children. Considerable overlap can occur in the clinical presentation of Lyme arthritis and acute septic arthritis. Early differentiation is critical, given the disparate therapeutic implications; Lyme arthritis is treated with outpatient oral antibiotics, while septic arthritis requires hospitalization, IV antibiotics, and, often, surgical drainage. We wanted to identify MRI features that may distinguish Lyme arthritis from septic arthritis in children. MATERIALS AND METHODS: Knee MR images in 11 children with Lyme arthritis and 7 with septic arthritis, with a mean age 10.6 years old and 11.7 years old, respectively, were reviewed by a radiologist blinded to the final diagnosis. Joint effusion size, synovial thickness, adenopathy, subcutaneous, marrow, and muscle edema on MRI; and clinical parameters including age, sex, fever, WBC, erythrocyte sedimentation rate, C-reactive protein, and joint fluid WBC in the two patient groups were compared using univariate and multivariate analyses. RESULTS: Subcutaneous edema was seen in all septic arthritis patients but in only one of 11 patients with Lyme arthritis (p < 0.01). Myositis and adenopathy were present in all Lyme arthritis patients and two of seven patients with septic arthritis (both p < 0.01). No significant difference was present in synovial thickness, marrow edema, or joint fluid size. There were no statistically significant differences in the clinical parameters assessed. CONCLUSION: Our results identified three MRI features, specifically, myositis, adenopathy, and lack of subcutaneous edema, that strongly suggest the diagnosis of Lyme arthritis rather than septic arthritis in children with acute inflammation of the knee. Awareness of these characteristic MRI features may avoid unnecessary invasive procedures and cost.

Arthritis, Infectious↗
PubMed2004

Noninvasive magnetic resonance spectroscopic imaging biomarkers to predict the clinical grade of pediatric brain tumors.

The diagnosis and therapy of childhood brain tumors, most of which are low grade, can be complicated because of their frequent adjacent location to crucial structures, which limits diagnostic biopsy. Also, although new prognostic biomarkers identified by molecular analysis or DNA microarray gene profiling are promising, they too depend on invasive biopsy. Here, we test the hypothesis that combining information from biologically important intracellular molecules (biomarkers), noninvasively obtained by proton magnetic resonance spectroscopic imaging, will increase the diagnostic accuracy in determining the clinical grade of pediatric brain tumors. We evaluate the proton magnetic resonance spectroscopic imaging exams for 66 children with brain tumors. The intracellular biomarkers for choline-containing compounds (Cho), N-acetylaspartate, total creatine, and lipids and/or lactate were measured at the highest Cho region and normalized to the surrounding healthy tissue total creatine. Neuropathological grading was done with WHO criteria. Normalized Cho and lipids and/or lactate were elevated in high-grade (n = 23) versus low-grade (n = 43) tumors, which multiple logistic regression confirmed are independent predictors of tumor grade (for Cho, odds ratio 24.8, P < 0.001; and for lipids and/or lactate, odds ratio 4.4, P < 0.001). A linear combination of normalized Cho and lipids and/or lactate that maximizes diagnostic accuracy was calculated by maximizing the area under the receiver operating characteristic curve. Proton magnetic resonance spectroscopic imaging, although not a proxy for histology, provides noninvasive, in vivo biomarkers for predicting clinical grades of pediatric brain tumors.

Aspartic Acid↗
PubMed2004

Infant sedation for MR imaging and CT: oral versus intravenous pentobarbital.

PURPOSE: To compare the effectiveness and safety of oral (PO) versus intravenous (IV) pentobarbital sedation for magnetic resonance (MR) imaging and computed tomography (CT) in infants younger than 12 months. MATERIALS AND METHODS: The institutional review board approved the review of medical records and determined informed consent to be unnecessary. All parents gave informed consent for patient sedation. Prior to MR imaging or CT, infants younger than 12 months were sedated with PO pentobarbital (4-8 mg per kilogram body weight) or IV pentobarbital (2-6 mg/kg), depending on the presence of an IV catheter or need for IV contrast medium. A computer database used to record sedation data was reviewed for data from January 1997 to September 2003. PO and IV sedation groups were compared for mean age, weight, dose, time to sedation, time to discharge, and duration of sedation with a two-sample Student t test. Multivariate analysis of covariance was used to determine whether differences in sedation time, time to discharge, and duration of sedation between groups were independent of age, weight, sex, American Society of Anesthesiologists physical status classification, dose, and type of procedure. Sedation effectiveness (outcome) was determined as the percentage of sedation failures in each group. Safety was determined separately for other adverse events as a total and for respiratory adverse events. RESULTS: A total of 2164 infants received 2419 (1264 PO, 1155 IV) doses of pentobarbital for sedation. Weight and sex were comparable between groups. Time to sedation was significantly longer with PO than with IV pentobarbital (18 minutes +/- 11 vs 7 minutes +/- 7; P < .01), but time to discharge was similar, at approximately 108 minutes +/- 35. Total adverse events rate during sedation was not significantly different (0.8% [PO] vs 1.3% [IV]), but incidence of abnormal oxygen saturation (5% decrease from baseline, >1 minute duration) differed significantly (0.2% [PO] vs 0.9% [IV]; P = .02). Sedation effectiveness was comparable (failure rate, 0.5% [PO] vs 0.3% [IV]; P = .76). CONCLUSION: PO pentobarbital has comparable effectiveness and a lower rate of respiratory complications compared with IV pentobarbital in infants younger than 12 months; its use should be considered, regardless of presence of an IV catheter.

Administration, Oral↗
PubMed2004

ADAM 12 cleaves extracellular matrix proteins and correlates with cancer status and stage.

ADAM 12 is a member of a family of disintegrin-containing metalloproteases that have been implicated in a variety of diseases including Alzheimer's disease, arthritis, and cancer. We purified ADAM 12 from the urine of breast cancer patients via Q-Sepharose anion exchange and gelatin-Sepharose affinity chromatography followed by protein identification by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Four peptides were identified that spanned the amino acid sequence of ADAM 12. Immunoblot analysis using ADAM 12-specific antibodies detected an approximately 68-kDa band identified as the mature form of ADAM 12. To characterize catalytic properties of ADAM 12, full-length ADAM 12-S was expressed in COS-7 cells and purified. Substrate specificity studies demonstrated that ADAM 12-S degrades gelatin, type IV collagen, and fibronectin but not type I collagen or casein. Gelatinase activity of ADAM 12 was completely abrogated by zinc chelators 1,10-phenanthroline and EDTA and was partially inhibited by the hydroxamate inhibitor Marimastat. Endogenous matrix metalloprotease inhibitor TIMP-3 inhibited activity. To validate our initial identification of this enzyme in human urine, 117 urine samples from breast cancer patients and controls were analyzed by immunoblot. The majority of samples from cancer patients were positive for ADAM 12 (67 of 71, sensitivity 0.94) compared with urine from controls in which ADAM 12 was detected with significantly lower frequency. Densitometric analyses of immunoblots demonstrated that ADAM 12 protein levels were higher in urine from breast cancer patients than in control urine. In addition, median levels of ADAM 12 in urine significantly increased with disease progression. These data demonstrate for the first time that ADAM 12 is a gelatinase, that it can be detected in breast cancer patient urine, and that increased urinary levels of this protein correlate with breast cancer progression. They further support the possibility that detection of urinary ADAM 12 may prove useful in the development of noninvasive diagnostic and prognostic tests for breast and perhaps other cancers.

ADAM Proteins↗
PubMed2004

Loss of collagen XVIII enhances neovascularization and vascular permeability in atherosclerosis.

BACKGROUND: Plaque neovascularization is thought to promote atherosclerosis; however, the mechanisms of its regulation are not understood. Collagen XVIII and its proteolytically released endostatin fragment are abundant proteoglycans in vascular basement membranes and the walls of major blood vessels. We hypothesized that collagen XVIII in the aortic wall inhibits the proliferation and intimal extension of vasa vasorum. METHODS AND RESULTS: To test our hypothesis, we bred collagen XVIII-knockout (Col18a1(-/-)) mice into the atherosclerosis-prone apolipoprotein E-deficient (ApoE(-/-)) strain. After 6 months on a cholesterol diet, aortas from ApoE(-/-);Col18a1(-/-) and ApoE(-/-);Col18a1(+/-) heterozygote mice showed increased atheroma coverage and enhanced lipid accumulation compared with wild-type littermates. We observed more extensive vasa vasorum and intimal neovascularization in knockout but not heterozygote aortas. Endothelial cells sprouting from Col18a1(-/-) aortas were increased compared with heterozygote and wild-type aortas. In contrast, vascular permeability of large and small blood vessels was enhanced with even heterozygous loss of collagen XVIII but was not suppressed by increasing serum endostatin to wild-type levels. CONCLUSIONS: Our results identify a previously unrecognized function for collagen XVIII that maintains vascular permeability. Loss of this basement membrane proteoglycan enhances angiogenesis and vascular permeability during atherosclerosis by distinct gene-dose-dependent mechanisms.

Animals↗
PubMed2004

Anchor design and bone mineral density affect the pull-out strength of suture anchors in rotator cuff repair: which anchors are best to use in patients with low bone quality?

BACKGROUND: Different metal and biodegradable suture anchors are available for rotator cuff repair. Poor bone quality may result in anchor loosening and tendon rerupture. HYPOTHESES: Higher bone mineral density is associated with higher pull-out strength of suture anchors. Depending on anchor placement, pull-out strengths of anchors are different within the greater tuberosity. STUDY DESIGN: Cadaveric biomechanical study. METHODS: Trabecular and cortical bone mineral densities were determined for different regions within the greater tuberosity. Metal screw-type and biodegradable hook-type anchors were cyclically loaded. RESULTS: Mean failure load of metal and biodegradable anchors was 273 N and 162 N, respectively, for the proximal part (P < .01) and 184 N and 112 N, respectively, for the distal part (P < .01). Both types of anchors showed higher failure loads in the proximal-anterior and -middle parts of the greater tuberosity than in the distal part (P < .01). A significant positive correlation was found between cortical bone mineral density and failure load of metal anchors (P < .01). CONCLUSION: Bone quality, anchor type, and anchor placement have a significant impact on anchor failure loads. CLINICAL RELEVANCE: Suture anchors should be placed in the proximal-anterior and -middle parts of the greater tuberosity. In the distal parts, biodegradable hook-like anchors should be used with caution.

Aged↗
PubMed2004

Endoscopic treatment of vesicoureteral reflux with autologous chondrocytes: postoperative sonographic features.

PURPOSE: To analyze sonographic imaging features of renal collecting systems, ureters, and bladder in 32 children after endoscopic treatment of vesicoureteral reflux with autologous chondrocytes and to determine whether any features are associated with persistent reflux. MATERIALS AND METHODS: Sonograms obtained at mean intervals of 1.4 and 12 months after treatment were compared with cystograms obtained at mean intervals of 2.7 and 12 months. Sonograms were analyzed for chondrocyte mound contour and volume, changes in mound volume over time, and presence of hydroureteronephrosis. Mean differences in mound volume were detected with paired t tests in 14 patients with early and late sonograms available for review. RESULTS: Early cystograms and sonograms were available for 25 of 32 patients (45 of 56 treated ureters). Reflux occurred in 16 of 45 ureters. In 16 ureters, chondrocyte mounds were absent in six, unilobed in seven, and multilobed in three. In 29 treated ureters without reflux, mounds were unilobed in 28 and multilobed in one. Three patients had mild hydronephrosis and one had distal hydroureter; these conditions resolved. Late cystograms and sonograms were available in 18 of 22 patients (30 of 38 treated ureters). Reflux occurred in seven of 30 ureters. In seven ureters, mounds were unilobed in five and multilobed in two. In 23 treated ureters without reflux, mounds were unilobed in 21 and multilobed in two. One patient had mild hydronephrosis that resolved. In 14 patients with early and late sonograms available for review, mean mound volume in late group (0.37 cm3 +/- 0.25 [standard deviation]) was significantly smaller than that in early group (0.56 cm3 +/- 0.39; P =.004, paired t test). CONCLUSION: Absence of chondrocyte mound or presence of multilobed mound contour was associated with persistent reflux. Mean mound volume decreased over time. Treatment-induced hydroureteronephrosis was uncommon and self-limited.

Adolescent↗