Biomedical subjects

T Georg

Publications and source records attributed to T Georg.

At least 19 recordsLinked to original sources

PubMed2005

Reference values of NT-proBNP serum concentrations in the umbilical cord blood and in healthy neonates and children.

BACKGROUND: N-terminal brain natriuretic peptide (NT-proBNP) is a neurohormonal substance secreted mainly by the cardiac myocytes of the left ventricle and to a less degree of the left atrium. The releasing mechanism is induced by an increased wall stress on the base of volume or pressure load of the ventricle. The physiologic actions of BNP are prohibition of the sympathetic activity, vasodilatation, natriuresis, diureses and inhibition of the renin-angiotensin system. Because of its high sensitivity and specifity in relation to the left ventricular incompetence, BNP as well as NTproBNP are well accepted markers of ventricular dysfunction. It was the aim of the study to establish reference values of NT-proBNP serum concentrations throughout childhood, in particular in the newborn age group. METHODS: In a cross sectional study, serum NT-proBNP concentrations were measured by an ElectroChemiLuminescenceImmunoAssay ("ECLIA" Roche) in the umbilical cord blood of 62 healthy full-term neonates and in 222 healthy probands from birth up to the age of 18 years. RESULTS: The concentration of NT-proBNP in the cord blood samples ranged from 281 to 2595 pg/ml (mean: 818 pg/ml). There was a significant increase in the first days of life followed by a rapid decrease during the first year and a further gradual decrease throughout infancy; beyond the 10(th) year of age normal adult values were approached. CONCLUSIONS: The knowledge of the normal range of plasma NT-proBNP levels in healthy subjects during childhood serves as a non-invasive marker for differentiation of pathologic conditions such as acute myocarditis, hypertrophic or dilated cardiomyopathy, tachyarrhythmias and pulmonary hypertension.

Adolescent↗

PubMed2005

[Body mass index, protein metabolism profiles and impact on IVF/ICSI procedure and outcome].

OBJECTIVE: Higher risks of infertility have been found in overweight women. The purpose of the present study was to explore whether protein metabolism profiles related to body mass index (BMI) and to find out whether these parameters should affect IVF/ICSI outcome. PATIENTS AND METHODS: 52 patients were enrolled in this study. All patients underwent an ovarian stimulation either with recombinant follicle stimulating hormone (Gonal-F) or human menopausal gonadotropin (Menogon) after pituitary down-regulation with Goserelin (Zoladex) or Triptorelin (Decapeptyl Gyn). Five blood samples were taken: before treatment, at the beginning of ovarian stimulation, on the day of HCG injection for the ovulation induction, on the day of follicle aspiration and 14 days after embryo transfer. The blood samples were analysed with regard to the serum concentrations of total protein, albumin, total bilirubin and urea. According to the BMI values the patients were divided into two groups: BMI < 25 kg/m (2) (GI, n = 28) and BMI > 25 kg/m (2) (GII, n = 24). The results of IVF/ICSI outcome were compared in both groups. RESULTS: In both groups, the serum concentrations of total protein, albumin, total bilirubin and urea decreased during ovarian stimulation. In GII, albumin concentration decreased significantly on the day of follicle aspiration (46.0 +/- 2.3 g/l versus 43.5 +/- 2.5 g/l, p < 0.001) and 14 days after embryo transfer (46.8 +/- 2.5 g/l versus 44.7 +/- 2.3 g/l, p < 0.002), whereas the concentration of total bilirubin was not significantly decreased on the day of HCG injection (0.57 +/- 0.29 mg/dl versus 0.49 +/- 0.26 mg/dl, p = 0.11). Furthermore, pregnancy rate in women with BMI < 25 kg/m (2) was 46.4 % and in women with BMI > 25 kg/m (2) 33.1 % (p = 0.34). CONCLUSIONS: Serum concentrations of albumin and total bilirubin are influenced by BMI. Excess weight defined as BMI > 25 kg/m (2) has a negative impact on IVF outcome leading to decreased chances of pregnancy.

Bilirubin↗

PubMed2004

Factors affecting the interface of cervical spine facet screws placed in the technique by Roy-Camille et al.

The objective of the study was to investigate the influence of bone cement, length of burr hole and bone density on pullout force and insertional screw torque of cervical spine facet screws. Both facets of 24 human cervical vertebrae were scanned for bone mineral density (BMD) and assigned to two groups for measuring of insertional screw torque and pullout strength. Maximal insertional screw torque was measured and removal of the screws was performed in displacement control (0.25 mm/s) without bone cement (PMMA), with 0.1 ml of PMMA and with the burr hole completely filled with PMMA. Screw torque was 59.1 N cm (+/-25.7 N cm), pullout force was 382.8 N (+/-140.5 N) without PMMA. Injection of 0.1 ml PMMA did not change significantly both screw torque (p=0.73) and pullout (p=0.129). Filling of the burr holes with PMMA increased significantly both screw torque (p<0.0001) and pullout force (p=0.028) when compared with injection of 0.1 ml of PMMA. A positive, moderate correlation was seen between BMD and screw torque before (r=0.501; p=0.097) and after filling with PMMA (r=0.514; p=0.088), BMD and pullout force before (r=0.441; p=0.152) and after complete filling with PMMA (r=0.673; p=0.047). The PMMA does increase both screw torque (p<0.0001) and pullout force (p=0.028) of facet screws significantly if the burr hole is filled with PMMA completely when compared with injection of 0.1 ml PMMA. Bone mineral density of the cervical facets moderately correlates with peak insertional torque and pullout force. This is true for a facet without PMMA and for a facet filled with PMMA. The length of the burr hole seems to be less important.

Bone Cements↗

PubMed2004

Reference values of fetal ductus venosus, inferior vena cava and hepatic vein blood flow velocities and waveform indices during the second and third trimester of pregnancy.

OBJECTIVE: Our objective was to establish reference values for ductus venosus, inferior vena cava and hepatic vein flow velocities during ventricular systole (S-wave) and diastole (D-wave), the lowest forward velocity during atrial contraction (a-wave), the intensity-weighted mean flow velocity (Vmean) and different calculated indices. METHODS: Venous flow velocity waveforms were obtained from 329 singleton pregnancies at 20-42 weeks of gestation by pulsed-wave color Doppler. Reference values were constructed by means of a quadratic regression model after logarithmic transformation of original data. RESULTS: With advancing gestational age the peak velocity index for the vein (PVIV) and pulsatility index for the vein (PIV) decreased whereas blood flow velocities increased. Blood flow velocities were highest in the ductus venosus and lowest in the right hepatic vein. Values for PVIV and PIV were highest in the hepatic vein and lowest in the ductus venosus. During atrial contraction there was a blood flow towards the fetal heart in the ductus venosus, whereas in the inferior vena cava and in the hepatic vein blood flow was either in the opposite from the fetal heart (reverse flow), or there was absent flow (zero flow) or flow was towards the fetal heart (positive flow). CONCLUSIONS: The reference ranges and calculated velocities established in this study may be utilized in studies dealing with the role of ductus venosus and inferior vena cava blood flow in fetuses with chromosomal abnormalities or congenital heart disease as well as hypoxic conditions. We speculate, that the reduction in PVIV and PIV with advancing gestational age may reflect a decrease in cardiac afterload as a result of maturation of diastolic ventricular function.

Blood Flow Velocity↗

PubMed2004

Lateralization in autonomic dysfunction in ischemic stroke involving the insular cortex.

Autonomic nervous system dysfunction is a common complication of ischemic stroke. Clinical and experimental data indicate hemispheric lateralization in the control of autonomic activity. The insular cortex has also been shown to play a crucial role in the central autonomic network. The aim of this study was to assess cardio-autonomic dysfunction in patients with ischemic insular versus non-insular cortex infarction, and to demonstrate a possible lateralization in autonomic activity mediated by the insular cortex. Sympathetic function was prospectively assessed by determining plasma norepinephrine and epinephrine in 15 patients with left-hemisphere (LH; four insular infarction), and 14 with right-hemisphere (RH) middle cerebral artery (MCA) stroke (five insular infarction). Systolic and diastolic blood pressure and heart rate were recorded during the first 5 days after stroke. Sympathetic activity was significantly higher in insular than in non-insular infarction (p < 0.05) with concomitantly elevated cardiovascular parameters in insular stroke patients. The pathological activation of the sympathetic nervous system was most excessive in RH-stroke involving the insular cortex (p < 0.05). Our data indicate a hemispheric lateralization in autonomic activity which is mediated by the right-sided insular cortex. Patients with RH stroke involving the insular cortex are most susceptible to develop cardio-autonomic dysfunction.

Aged↗

PubMed2004

Variation of endplate thickness in the cervical spine.

The purpose of the study was to investigate possible variation of thickness of the cervical spine endplate with respect to endplate orientation (superior or inferior endplate) and level distribution (C4-C7). Six human cervical spine segments C4-C7 were used to create six specimen of C4, C5, C6, and C7, respectively. The bony endplates of each vertebra were cleaned carefully from disc tissue without damaging the endplates. Six endplates with severe degenerative changes were excluded from the study. The posterior elements were removed, and a midaxial cut using a bone saw was performed through each vertebral body, thus producing a superior and inferior half. Each half-vertebra was then glued onto a piece of wood with the endplate oriented upwards and horizontally. For each specimen, four computed tomography scans were taken and thickness of the endplate was measured at five points on each scan perpendicular to the midaxial cut. Factorial analysis of variance (ANOVA) and Scheffe-test were used to detect significant differences. All peripheral regions were significantly thicker than the central point of the endplate if all measuring points were considered for statistical analysis, regardless of scan, endplate orientation or level (Scheffe-test, P<0.001). In both superior and inferior endplates, peripheral areas were thicker than the central region (Scheffe-test, P<0.001). For all levels, the endplate within the peripheral regions was thicker than within the central region and the difference reached significance for the superior and inferior endplate of C4, C5, and C6 and the inferior endplate of C7 (Scheffe-test, P<0.05). The peripheral regions of the cervical spine endplate are usually thicker than its central region, regardless of endplate orientation and level (C4, C5, C6, C7) distribution.

Aged↗

PubMed2004

[Effects of ovarian stimulation on serum concentrations of lipids and ketone bodies in patients undergoing IVF/ICSI treatment].

OBJECTIVE: The ovarian stimulation increase the estradiol concentration in comparison to the one observed in the menstrual cycle. The aim of the study was to determine the influence of ovarian stimulation on serum concentrations of lipids and ketone bodies in patients undergoing IVF/ICSI treatment. PATIENTS AND METHODS: 50 patients were included in this study. All patients underwent an ovarian stimulation either with recombinant follicle stimulating Hormone (Gonal-F, n = 28) or human menopausal gonadotropin (Menogon, n = 22) after pituitary down-regulation with Goserelin or Triptorelin. Five blood samples were taken: before treatment, at the beginning of ovarian stimulation, on the day of HCG injection for the ovulation induction, on the day of follicle aspiration and 14 days after embryo transfer. Afterwards, the samples were analysed with regard to the concentrations of triglyceride, total-cholesterol, HDL-/LDL-cholesterol, acetoacetate, beta-hydroxybutyrate and alpha-ketoglutarate. RESULTS: During the ovarian stimulation, total-cholesterol andA'LDL-cholesterol decreased significantly (p(Chol) < or = 0.001; p(LDL) < or = 0.001), whereas the concentration of HDL-cholesterol increased significantly (p(HDL) < or = 0.001). Furthermore, a significant increase of beta-hydroxybutyrate and alpha-ketoglutarate has been detected (p(HBS) = 0.039; p (KG) = 0.023). CONCLUSIONS: The observed changes in serum concentrations of lipids and ketone bodies began with the application of gonadotrophins for stimulation and persisted until the end of the treatment. Therefore, the increase of estradiol, stimulated by gonadotrophins, seems to be responsible for the changes in the serum concentrations of lipids and ketone bodies. All women undergoing ovarian stimulation should be monitored for long-term thrombogenic and atherogenic risks.

3-Hydroxybutyric Acid↗

PubMed2003

Reference values of ductus venosus blood flow velocities and waveform indices from 10 to 20 weeks of gestation.

OBJECTIVE: Our objective was to establish reference values for ductus venosus flow velocities during ventricular systole (S wave) and diastole (D wave), the lowest forward velocity during atrial contraction (A wave) and different calculated indices [(S-A)/D), (S-A)/Vmean, (S-A)/S, S/A, S/D)]. METHODS: Ductus venosus flow velocity waveforms were obtained from 329 singleton pregnancies at 10-20 weeks of gestation by pulsed-wave color Doppler. Reference values were constructed by means of a quadratic regression model after logarithmic transformation of original data. RESULTS: A significant increase in blood flow velocity during atrial contraction [A-wave, (3.5 cm/s to 9.9 cm/s and 12.9 cm/s to 66.3 cm/s respectively, 5-95% centile)], during ventricular systole [S-wave, (19.2 cm/s to 30.1 cm/s and 45.1 cm/s to 84.9 cm/s respectively, 5-95% centile)] and during early ventricular diastole [D-wave, (15.7 cm/s to 26.1 cm/s and 37.9 cm/s to 77.9 cm/s respectively, 5-95% centile)]. The venous indices values decreased with increasing gestational age. In 3 of 329 fetuses (0.91%) a reversed flow during atrial contraction was seen. CONCLUSION: Assessment of ductus venosus blood flow velocities during first and second trimester is feasible by means of color Doppler flow. The reference ranges and calculated velocities established in this study may be utilized in studies dealing with the role of ductus venosus blood flow in chromosomal abnormal fetuses, fetuses with congenital heart disease or fetal myocardial insufficiency of hypoxic origin.

Adolescent↗

PubMed2003

[A population-based survey of critical care].

OBJECTIVES: Results of a population-based survey of critical care in a German state are presented. The indication for critical care was derived using the APACHE-II score,which measures the physiologic state of patients, and the TISS-28 score as a measure for expenditure of critical care. METHODS: During 3 months all adult patients of intensive care units in Saarland, a German state with 1.08 million residents,were included. All kinds of hospitals were involved. Completeness and validity of data are proved. RESULTS: The TISS score was registered daily on 13,391 adult patients with 54,503 days, the APACHE score during admission and discharge of intensive care units only. The correlation between the scoring-systems and indication, kind of care (critical care vs. intermediate care), kind of hospital, and ICD-10 diagnoses is analysed in this paper. CONCLUSIONS: In this study the population-based critical care in a state is analysed the first time. It completes previously published studies,which were performed at the level of hospitals and departments.

APACHE↗

PubMed2003

[Reliability and validity of the Wender-Utah-Rating-Scale short form. Retrospective assessment of symptoms for attention deficit/hyperactivity disorder].

The diagnosis of adult attention deficit/hyperactivity disorder (ADHD) requires the retrospective assessment of ADHD symptoms in childhood. The Wender Utah Rating Scale (WURS) is helpful in detecting ADHD-associated symptomatology in childhood. A German short version (WURS-k) of this instrument has been made available recently. In the present study, we investigated the validity of the WURS-k. In a population of 63 adult ADHD patients (according to ICD-10 and DSM-IV criteria) and 1,303 male controls, ROC analysis indicated a sensitivity of 85% and specificity of 76% at a cutoff of 30 points. In ADHD patients, seven individual factors explained 70.3% of the variance. The highest diagnostic precision was demonstrated using the WURS-k total score. The seven extracted factors of the WURS-k did not differ in diagnostic value. Significant correlations were found between impulsivity according to Eysenck's Impulsivity Questionnaire (EIQ) and excitability, aggression, emotional lability, and satisfaction on the Freiburg Personality Inventory (FPI-R) in ADHD patients. Concerning a 30-50% persistence of ADHD symptomatology in adults, these correlations underline the diagnostic validity of the WURS-k. The scale manifested excellent internal consistency (alpha=0.91) and a split-half correlation of r(12)=0.85.

Adult↗

PubMed2003

Fibroblast growth factor (FGF), intracellular adhesion molecule (sICAM-1) level in serum and follicular fluid of infertile women with polycystic ovarian syndrome, endometriosis and tubal damage, and their effect on ICSI outcome.

PROBLEM: The objective of this study was to determine the concentration of fibroblast growth factor (FGF) and soluble intracellular adhesions molecule (sICAM-1) in serum and follicular fluid (FF) of polycystic ovary (PCO), endometriosis and tubal factor infertility and male factor infertility patients, and to investigate the relationship between these parameters and the outcome of intracytoplasmic sperm injection (ICSI). METHOD OF STUDY: The concentration of FGF and sICAM-1 in serum and FF were determined in patients undergoing controlled ovarian hyperstimulation (COH) for ICSI therapy for various etiology of infertility and the results of cytokines concentration and ICSI outcome were compared between the groups. Twenty patients with PCO (G.I), 17 with endometriosis (G.II), 19 with tubal damage (G.III) and 19 with male factor infertility (G.IV) were enrolled in this study. Quantitative determination of levels of FGF and sICAM-1 was performed using enzyme-linked immunosorbent assays (ELISAs). RESULTS: The FGF level in serum of PCO patients (G.I) were 4.8 +/- 2.3 and in FF were 104.0 +/- 39.0 pg/mL. The corresponding values in the endometriosis patients group (G.II) were 5.9 +/- 3.1 and 125.4 +/- 74.9 pg/mL. The concentration of FGF in tubal factor infertility group (G.III) in serum was significantly higher (P = 0.009) than those observed in the PCO group (G.I) 7.4 +/- 4.5 pg/mL, whereas the concentration in FF was at the same level like the other groups investigated, 128.7 +/- 75.9 pg/mL. Besides, the sICAM-1 (pg/ml) concentration in FF showed a significant difference between the groups investigated (G.I, 175.3 +/- 52.8; G.II 194.4 +/- 32.2; G.III 233.1 +/- 54.3; and G.IV 215.1 +/- 54.4 ng/mL; P = 0.003). The sICAM-1 levels in serum were not significantly different between the groups (217.0 +/- 42.9; 216.3 +/- 73.6; 254.8 +/- 79.6; 237.56 +/- 78.4 ng/ml; P = 0.267). The fertilization rate was significantly higher in G.III (66.0 +/- 23.89%) in comparison to G.II (38.8 +/- 33.9%; P = 0.014) or G.IV (38.7 +/- 22.7%; P = 0.012). The pregnancy rates were similar in all groups (30, 35.3 and 35.0, 38.6%, respectively). CONCLUSION: Both, FGF and sICAM-1 are present in serum and FF of patients undergoing controlled ovarian hyperstimulation for ICSI therapy. The FGF concentration in serum differs significantly between the groups investigated, whereas, no significant difference could be observed in the FF concentration of FGF. On the other hand, the sICAM in serum showed no significant difference between the groups, whereas, sICAM in FF demonstrated a significant difference between the patient groups investigated. On the whole, the ICSI outcome was not related to serum or FF concentrations of FGF or sICAM-1. Therefore, the mean concentration of FGF and sICAM-1 in serum and in FF could not be used to predict the fertilization rate in an ICSI program.

Biomarkers↗

PubMed2003

Comparison between cytokine concentration in follicular fluid of poor and high responder patients and their influence of ICSI-outcome.

OBJECTIVE: The aim of this study was to compare the cytokine concentration in follicular fluid (FF) of low and high responder intracytoplasmic sperm injection (ICSI) patients and to find out the impact of these cytokines in FF on ICSI outcome. DESIGN: The levels of insulin-like growth factor (IGF)-I, IL-6, IL-8, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), granulocyte-macrophage-colony stimulating factor (GM-CSF) were measured from low and high responder ICSI patients, the results were compared between the two groups and their influence on ICSI outcome was analysed. MATERIAL AND METHODS: A total of 49 low (G.I) and 34 high (G.II) responder patients were enrolled in this study. FF was collected at the time of oocyte retrieval and measured either by enzyme-linked immunosorbent assay (IL-6, IL8, EGF, PDGF, GM-CSF) or radio immuno assay (IGF-I). RESULTS: The concentration of IL-6 (pg/mL), IL-8 (pg/mL), IGF-I (ng/mL), PDGF (pg/mL), EGF (pg/mL), GM-CSF (pg/mL) in G.I was 6.0 +/- 4.3, 288.1 +/- 139.2, 0.416 +/- 0.089, 249.8 +/- 150.1, 9.12 +/- 5.5 and 1.45 +/- 2.10 and the corresponding value in G.II was 7.4 +/- 4.8, 208.6 +/- 64.0, 0.431 +/- 0.094, 387.6 +/- 36.0, 8.9 +/- 5.4 and 1.8 +/- 3.3, respectively. Only the PDGF concentration showed a significant (P = 0.007) difference between the two groups. Besides, negative correlations were found between PDGF and fertilization rate (r = -0.287; P = 0.046) of G.I. The mean number of retrieved (6.4 +/- 2.3 versus. 15.7 +/- 5.4) and fertilized (3.6 +/- 1.6 versus 7.0 +/- 4.5) oocytes differ significantly (P = 0.001) between the two groups. The fertilization rate was significantly higher in G.I than in G.II (60.9 +/- 25.1 versus 43.4 +/- 20.7%). CONCLUSION: There was no significant difference between IGF-I, IL-6, IL-8, EGF and GM-CSF concentrations of low and high responder patients. Besides, PDGF was significantly (P = 0.007) higher in high responder compared with low responder patients. Moreover, in poor responder patients, a negative correlation was found between PDGF and fertilization rate. However, the cytokine levels in FF of the patients undergoing controlled ovarian hyperstimulation for ICSI could not be used as a marker of oocyte fertilization and implantation potential.

Adult↗

PubMed2003

[Association between ovarian stimulation regime and protein metabolism of patients undergoing IVF/ICSI therapy].

The aim of this study was to determine the relationship between the ovarian stimulation protocol (with HMG or FSH) after down-regulation with GnRH anologa and protein (total protein and albumin) as well as bilirubin and urea in serum. Furthermore, it was intended to find out the effect of these parameters on IVF/ICSI outcome. 50 patients were included in this study. All patients underwent controlled ovarian hyperstimulation for assisted reproduction therapy either with FSH (Gonal-F) or HMG (Menogon). Ovulation induction was induced by human chorionic gonadotrophine (HCG, Predalon) 10 000 IU i. m. The protein concentration (total protein, albumin) as well as bilirubin and urea concentrations were determined before down-regulation with GnRHa, at the beginning of ovarian stimulation with FSH or HMG, on the day of ovulation induction with HCG, during oocyte retrieval and fourteen days after embryo transfer. The age, body mass index and etiology of infertility showed no significant difference between patients stimulated with HMG or FSH. Total protein and albumin concentration decreased significantly (p=0.001) from 77.45 +/- 5.90 g/L and 47.02 +/- 3.41 g/L to 74.60 +/- 4.6 g/L and 45.04 +/- 2.39 g/L, respectively at the time of oocyte retrieval. Whereas, no significant change with bilirubin and urea concentration was observed. However, the mean concentration of total protein, albumin, bilirubin of patients who become pregnant was higher of those who did not. In conclusion, this study shows that total protein and albumin concentration in plasma decreased during the follicular phase significantly with the application of exogenous gonadotrophins and steroid hormones in comparison to the value before down-regulation. The mean value of total protein, albumin, bilirubin of patients who become pregnant was higher (but not significant) of those who did not. However, the high individual variation in the present results shows that these parameters are not useful as a predictor of IVF/ICSI outcome.

Blood Proteins↗

PubMed2003

Location-dependent patterns in cardio-autonomic dysfunction in ischaemic stroke.

BACKGROUND AND STUDY PURPOSE: Autonomic nervous system dysfunction is a common complication of acute cerebrovascular disorders. The aim of this study was to investigate a possible location-dependent difference in cardio-autonomic function in patients with ischaemic stroke. PATIENTS AND METHODS: Sympathetic function was prospectively assessed by determining plasma norepinephrine and epinephrine in 19 patients with left-hemisphere (LH), 14 with right-hemisphere (RH) and 6 with brainstem/cerebellar (BS) stroke. Blood pressure, heart rate, cardiac output and transcranial flow velocity in the middle cerebral artery were recorded during the first 5 days after stroke. RESULTS: Stroke caused an initial increase in sympathetic function in all 3 groups with a spontaneous decrease in norepinephrine in LH (p < 0.01) and BS stroke (p < 0.05) only. Norepinephrine was significantly higher in RH than in BS stroke (p < 0.05). The alterations in autonomic function were paralleled by a sustained elevation in cardiovascular parameters mainly in RH stroke. CONCLUSIONS: Plasma catecholamines are feasible in monitoring location-dependent autonomic dysfunction in ischaemic stroke. Hemispheric lateralization in autonomic control should be taken into account in the management of stroke because of an increased susceptibility to cardio-autonomic dysfunction in patients with RH stroke.

Aged↗

PubMed2003

[Biodegradable meniscus fixations: a comparative biomechanical study].

PURPOSE: Numerous new all inside meniscus repair techniques using biodegradable fixation devices have become available in the last years. Few studies have dealt with the biomechanical properties of these implants so far. The aim of this study was to analyze meniscus repairs under cyclic loading conditions for different fixation devices (Meniscus Arrow, Clearfix Meniscal Screw, Meniscal Dart, BioStinger) and to compare them to standard suture techniques. MATERIAL AND METHODS: Eighty meniscus repairs on 27 medial porcine menisci were performed. For biomechanical testing loosening, number of failures, failure modes and failure loads were evaluated under cyclic and maximum loading conditions. Testing was performed on a materials testing machine. RESULTS: During cyclic loading 10 out of 40 (25%) fixation devices failed. A gap appeared between the 2 parts of the meniscus within the first loading cycles. The failure strengths obtained with the 4 meniscus fixation devices did not differ significantly (Meniscus Arrow: 44 N; Clearfix Meniscal Screw: 35 N; Meniscal Dart: 33 N; BioStinger: 54 N). Besides for the BioStinger, the values of the sutures were significantly higher. The use of a stronger suture material (PDS 0) increased the failure load significantly. During maximum loading the fixation devices failed by both pull-out of the head or the tip of the device, except for the BioStinger showing only pull-out of the head. All sutures failed by breakage, except for the PDS 0 horizontal sutures in which 50% of complete tissue failures could be noted. CONCLUSION: This study shows that meniscal fixation devices may fail under repetitive loading conditions. A gap appeared between the meniscal margins within the first loading cycles irrespective of the suture type and fixation device used. Both gapping and failure modes of the fixation devices may be design-specific. The maximum failure loads differed significantly between the bioabsorbable devices and the sutures. Stronger suture materials increased the failure loads significantly. To allow a complete evaluation of new meniscus fixation devices not only biomechanical, but also biological and clinical parameters need to be analyzed in forthcoming studies.

Absorbable Implants↗

PubMed2001

Effect of an Er:YAG laser on periodontally involved root surfaces: an in vivo and in vitro SEM comparison.

BACKGROUND AND OBJECTIVE: The recently introduced Er:YAG laser seems to be a promising alternative in periodontal treatment due to its thermo-mechanical ablation mechanism. The present study attempted to compare the effects of an Er:YAG laser on periodontally involved root surfaces at different power settings in vivo and in vitro using scanning electron microscopic (SEM) observations. STUDY DESIGN/MATERIALS AND METHODS: Forty single rooted teeth (160 surfaces), with advanced periodontal destruction that were scheduled for extraction, were divided into two groups of 80 each which were treated in vivo (group A) and immediately after extraction in vitro (group B) using one of the following energy settings: 120, 140, 160, and 180 mJ at 10 Hz (71, 83, 94, and 106 J/cm(2)/pulse). The morphological changes on the treated root surfaces were evaluated using scanning electron microscopic (SEM) observations to assess the laser induced ultrastructural changes. The severity of the changes was evaluated according to an arbitrary scale in 7 degrees [1-7]. Untreated peripheral areas served as control. RESULTS: All surfaces treated in vitro (group B) showed visible crater-like defects with notch-edged borders. The depth of the surface damages varied with the power applied and was localized into cementum at energy settings of 120-160 mJ but also reached dentine at 180 mJ. Compared to that, all in vivo (group A) treated surfaces showed a homogeneous and smooth root surface morphology. The surface alterations were not related to the used energy setting. CONCLUSIONS: The results of the present study showed that the clinical use of an Er:YAG laser resulted in a smooth root surface morphology, even at higher energy settings. The results also seem to indicate that calculus removal can be selectively done in vivo.

Dental Calculus↗

PubMed2001

Blood loss in anterior cruciate ligament (ACL) reconstruction with and without intercondylar notchplasty: does it affect the clinical outcome?

Blood loss is associated with any surgical procedure and should be reduced wherever possible. It was our impression that notchplasty adds to the amount of postoperative bleeding after anterior cruciate ligament (ACL) reconstruction. With posterior placement of the tibial tunnel, notchplasty is optional in many cases. This study aimed to quantify blood loss with and without notchplasty after arthroscopically assisted ACL reconstruction using bone-patellar tendon-bone autografts. We performed a prospective clinical study of 58 patients, who had undergone arthroscopically assisted autogenous patellar tendon ACL reconstruction. In group I, a notchplasty was necessary according to the local anatomical criteria (intraoperative impingement test). In group II, ACL replacement could be performed without notchplasty. Single and total day drainage volume, serum and suction drain hemoglobin (Hb) and hematocrit (Hct) levels were monitored. One year after surgery, the patients were reviewed to assess the outcome according to the IKDC and Lysholm scores and the KT-1000 arthrometer. The total drainage volume was 448 ml (range 150-550 ml) in group I and 299 ml (range 50-420 ml) in group II (p < 0.001). The serum hematocrit (Hct) decrease was 9.7% in group I and 7.4% in group II (p < 0.001). At 12 months after surgery, the IKDC and Lysholm score evaluations and the KT-1000 arthrometer measurements revealed no clinical differences between the notchplasty and non-notchplasty groups. Despite a 30% increase in blood loss, notchplasty has been shown to be a useful procedure to prevent graft impingement without negative side-effects.

Adult↗

PubMed2001

Pulmonary thromboendarterectomy--risk factors for early survival and hemodynamic improvement.

OBJECTIVE: Pulmonary thromboendarterectomy (PTE) for chronic thromboembolic pulmonary hypertension is a challenging procedure with a considerable mortality. The aim of this investigation was to identify risk factors influencing mortality and operative results. METHODS: Between October 1995 and August 2000, 69 patients (age 54 years; 34 women; mean New York Heart Association (NYHA) stage 3.4) underwent PTE. The preoperative pulmonary vascular resistance (PVR) was 988+/-554 dynes x s x cm(-5), mean pulmonary artery pressure 50+/-12 mmHg, right atrial pressure (RAP) 11.5+/-4 mmHg. Hospital mortality was 10.1% (n=7/69). Mean postoperative PVR on the 2nd day was 324+/-188 dynes x s x cm(-5). Pulmonary angiography was reviewed for number of involved segments (mean 9.3+/-2) and bronchial arteries diameter (BAD; mean 4.6+/-1.6 mm). A univariate and multivariate analysis was performed to determine preoperative risk factors for hospital death and inadequate hemodynamic improvement. RESULTS: By univariate analysis, mortality was influenced by age (P=0.04), right atrial pressure (P=0.009), NYHA (P=0.02) and the number of angiographically involved segments (P=0.02). Sex, left ventricular function, presence of coronary artery disease and bronchial artery diameter did not show correlation with mortality. Inadequate hemodynamic improvement in a dichotomized analysis (PVR > or =500 dynes x s x cm(-5), n=11, and PVR < 500 dynes x s x cm(-5), n=58), assessed by univariate analysis, was significantly influenced by age (P=0.02), preoperative PVR (P=0.01), NYHA (P=0.002), RAP (P=0.02) and female sex (P=0.02). Multivariate analysis identified age (P=0.1), RAP (P=0.002) and female sex (P=0.007) as risk factors for inferior hemodynamic improvement. CONCLUSIONS: Preoperative parameters can be utilized to assess postoperative mortality and hemodynamic improvement after pulmonary thromboendarterectomy. Patient age and clinical deterioration of pulmonary hypertension are considerable preoperative factors influencing hospital mortality. Inadequate postoperative hemodynamic improvement is affected by severity of disease and female sex.

Adolescent↗