Three-Dimensional Soft Tissue Prediction Using Finite Elements

BACKGROUND AND AIM: The goal of this study was to analyze the validity and prediction accuracy of a newly-developed procedure for three-dimensional soft tissue prediction based on Finite Element Method, and to compare the results with prediction produced using an existing two-dimensional prediction program (Dentofacial Planner Plus). PATIENTS AND METHODS: In twelve patients who underwent combined surgical-orthodontic treatment, profile prediction was generated using both procedures preoperatively and then compared at predefined measurement points with the patient's actual postoperative soft tissue status. RESULTS: The deviations observed depended on the facial region, whereby the prediction errors for both procedures were much greater in the lower facial third than in the midfacial third. Calculating in all the measurement points, the mean horizontal prediction error was 0.32 mm for the Finite Element Method and 0.75 mm for the Dentofacial Planner Plus. Overall, we were able to demonstrate the new procedure's superior validity and quality of visualization. In addition to profile prediction, the procedure allows a differentiated three-dimensional assessment of esthetically important regions such as the cheeks, nasolabial folds and the nasal wings. Additional X-radiation is not necessary in this risk-free and stress-free procedure. CONCLUSION: Three-dimensional soft tissue prediction employing finite element modeling is a useful aid for implementing esthetically-optimized treatment planning.     

Electrophysiological and arrhythmogenic effects of intramyocardial bone marrow cell injection in patients with chronic ischemic heart disease

BACKGROUND: Bone marrow cell injection has been introduced to treat patients with ischemic heart disease. However, focal application of bone marrow cells may generate an arrhythmogenic substrate. OBJECTIVES: To assess the electrophysiological and arrhythmogenic effects of intramyocardial bone marrow cell injection in patients with chronic myocardial ischemia. METHODS: Bone marrow was aspirated in 20 patients (65+/-11 years, 19 male) with drug-refractory angina and myocardial ischemia. Electroanatomical mapping (NOGA, Biosense-Webster, Waterloo, Belgium) was performed during mononuclear cell isolation. Areas for cell injection were selected based on the localization of ischemia on SPECT. These areas were mapped in detail to evaluate local bipolar electrogram duration, amplitude and fragmentation. Mononuclear cells were injected in the ischemic area with the NOGA system. SPECT and electroanatomical mapping were repeated at 3 months. Holter monitoring was repeated at 3 and 6 months. RESULTS: SPECT revealed a decrease in the number of segments with ischemia (3.5+/-2.5 vs. 1.1+/-1.0 at 3 months; P<0.01) and an increased left ventricular ejection fraction (44+/-13% vs. 49+/-17% at 3 months; P=0.02). The number of ventricular premature beats remained unchanged (10+/-24x10(2)/24h vs. 8+/-23x10(2)/24h at 3 months (P=NS) and 12+/-30x10(2)/24h at 6 months (P=NS)). At 3 months follow-up, bone marrow cell injection did not prolong electrogram duration (15.9+/-4.6 ms vs. 15.6+/-4.0 ms; P=NS), decrease electrogram amplitude (3.8+/-1.5 mV vs. 3.8+/-1.5 mV; P=NS), or increase fragmentation (2.0+/-0.5 vs. 1.9+/-0.4; P=NS). CONCLUSION: Intramyocardial bone marrow cell injection does not increase the incidence of ventricular arrhythmias and does not alter the electrophysiological properties of the injected myocardium.     

Mapping scores onto stages: mini-mental state examination and clinical dementia rating.

OBJECTIVE: Although the clinical course of Alzheimer disease (AD) is gradual, it is useful for a number of reasons to distinguish between different levels of severity. The Clinical Dementia Rating (CDR) has demonstrated high validity and reliability for this purpose, but it requires a considerable amount of data to be collected both from the patient and from an informant. In the present study, the authors mapped Mini-Mental State Examination (MMSE) scores onto CDR categories to determine how well the MMSE performs as a surrogate of the CDR as a timesaving method of staging dementia. METHOD: Eight hundred sixty-three probands, including 524 patients with probable AD, 92 patients with questionable dementia, and 247 with memory complaints but no objective cognitive impairment, were included. Cutoff scores were identified on one-half of the sample using a receiver operating characteristic analysis. The cutoff values were then applied to the other half of the sample, and the agreement between MMSE score ranges and CDR stages was determined by calculating Cohen's kappa. RESULTS: The MMSE discriminated well between CDR stages 0.5, 1, 2, and 3 but performed poorly in the separation between CDR stages zero and 0.5. The MMSE ranges were 30 for no, 26-29 for questionable, 21-25 for mild, 11-20 for moderate, and 0-10 for severe dementia. Substantial agreement between the two instruments was obtained for the categories mild (kappa=0.62, p<0.001, N=115), moderate (kappa=0.69, p<0.001, N=114), and severe dementia (kappa=0.76, p<0.001, N=39), whereas the agreement was moderate for no (kappa=0.44, p<0.001, N=120) and only fair for questionable dementia (kappa=0.28, p<0.001, N=42). CONCLUSION: The MMSE can be used as a surrogate measure for the CDR for the staging of dementia in AD.     

Disposition of oral and intravenous pravastatin in MRP2-deficient TR- rats.

The aim of this study was to characterize the role of the efflux transporter Mrp2 (Abcc2) in the pharmacokinetics of orally and intravenously administered pravastatin in rats. Eight Mrp2-deficient TR- rats and eight wild-type rats were given an oral dose of 20 mg/kg pravastatin. Four TR- animals and four wild-type animals were studied after intravenous administration of pravastatin (5 mg/kg). The TR(-) rats showed a 6.1-fold higher mean area under the plasma concentration-time curve (AUC) of pravastatin (p < 0.001) after oral administration and a 4.7-fold higher AUC (p < 0.01) after intravenous administration of pravastatin as compared with the wild-type animals. The mean systemic (total) clearance of pravastatin was 4.6-fold higher (39.2 versus 8.50 l/h/kg, p < 0.001) and the mean V 4.3-fold higher (14.1 versus 3.29 l/kg, p < 0.01) in the wild-type rats. The mean renal clearance of pravastatin in the TR(-) rats was 16.5-fold increased as compared with the wild-type animals (0.695 versus 0.042 l/h/kg, p < 0.05). The increased systemic exposure to oral pravastatin in the TR- rats was associated with a greater inhibitory effect on 3-hydroxy-3-methylglutaryl CoA reductase, as shown by smaller lathosterol to cholesterol concentration ratios. These results suggest that the reduced biliary pravastatin excretion in the Mrp2-deficient TR- rats is partly compensated for by increased urinary excretion of pravastatin. Furthermore, intestinal Mrp2 does not appear to play a major role in the oral absorption of pravastatin in normal rats.     

Temporomandibular joint: surgically created disk displacement causes arthrosis in the rabbit.

To document a causal relationship between temporomandibular joint disk displacement and arthrosis, the disk was surgically displaced in one temporomandibular joint in each of three rabbits. The rabbits were sacrificed after 4 weeks and the mandibular condyles were studied radiographically and histologically. All three joints that underwent disk displacement had radiographic and histologic evidence of arthrosis, which included erosion of the bone, irregularity and fissure formation of the articular soft tissue cover, disruption of the subchondral layer of cartilage cells, and chondrocyte proliferation. No radiographic or histologic changes occurred in the joints that were untouched. The results suggest that surgically created disk displacement can cause arthrosis in the temporomandibular joint of the rabbit.     

Obesity in Diabetic Patients Undergoing Coronary Artery Bypass Graft Surgery Is Associated with Increased Postoperative Morbidity

Background: Despite the fact that obesity is a known risk factor for cardiovascular disease, many studies have failed to demonstrate that obesity is independently associated with an increased risk of cardiovascular morbidity and mortality in nondiabetic patients undergoing coronary artery bypass graft surgery. The authors investigated the influence of obesity on adverse postoperative outcomes in diabetic and nondiabetic patients after primary coronary artery bypass surgery.

Methods: A retrospective cohort study of patients undergoing primary coronary artery bypass surgery (n = 9,862) between January 1995 and December 2004 at the Texas Heart Institute was performed. Diabetic (n = 3,374) and nondiabetic patients (n = 6,488) were classified into five groups, according to their body mass index: normal weight (n = 2,148), overweight (n = 4,257), mild obesity (n = 2,298), moderate obesity (n = 785), or morbid obesity (n = 338). Multivariate, stepwise logistic regression was performed controlling for patient demographics, medical history, and preoperative medications to determine whether obesity was independently associated with an increased risk of adverse postoperative outcomes.

Results: Obesity in nondiabetic patients was not independently associated with an increased risk of adverse postoperative outcomes. In contrast, obesity in diabetic patients was independently associated with a significantly increased risk of postoperative respiratory failure (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.41-3.61; P < 0.001), ventricular tachycardia (OR, 2.27; 95% CI, 1.18-4.35; P < 0.02), atrial fibrillation (OR, 1.56; 95% CI, 1.03-2.38; P < 0.04), atrial flutter (OR, 2.38; 95% CI, 1.29-4.40; P < 0.01), renal insufficiency (OR, 1.66; 95% CI, 1.10-3.41; P < 0.03), and leg wound infection (OR, 5.34; 95% CI, 2.27-12.54; P < 0.001). Obesity in diabetic patients was not independently associated with an increased risk of mortality, stroke, myocardial infarction, sepsis, or sternal wound infection.     

New synthetic analogs of lipid A as lipopolysaccharide agonists or antagonists of B lymphocyte activation.

We have studied the ability of synthetic analogs of lipid A to mimic lipopolysaccharide (LPS) for activation of 70Z/3 pre-B cells (expression of surface Igs) or to antagonize this effect. The results indicate that the presence of glucosamine (mono- or disaccharide) as a 'backbone' for the attachment of fatty acids is not necessary for activation of cells of the B lineage. Phosphate groups are not necessary either. Other structural features such as the configuration of particular asymmetric carbons, and the distance between an anionic group and an N-acyl chain, seem to be much more critical parameters for activation of B cells. Among the synthetic lipids which were unable to activate 70Z/3 cells, one compound, consisting of N,N-acylated and bisphosphorylated 2,3-dideoxy-2,3-diamino-D-glucose, behaved as a specific LPS antagonist and blocked also the activation triggered by the other synthetic inducers. The influence of the synthetic lipids on the entry of mature mouse B lymphocytes into the G1A phase of the cell cycle (cell enlargement) was also investigated. A high correlation was observed between the potency to activate pre-B cells and the ability to induce blast formation in mature B cells.