Biomedical subjects

T Georg

Publications and source records attributed to T Georg.

45 records · Page 3Linked to original sources

PubMed1999

Amelioration of lung reperfusion injury by L- and E- selectin blockade.

OBJECTIVE: Reperfusion injury is the main reason for early graft failure after lung transplantation. Inhibition of the adherence of polymorphonuclear leukocytes to activated endothelium by blocking L- and E-selectins (antibody EL-246) could potentially inhibit reperfusion injury. METHODS: Reperfusion injury was induced in a left lung autotransplant model in sheep. After hilar stripping the left lung was flushed with Euro-Collins solution and preserved for 2 h in situ at 15 degrees C. After reperfusion right main bronchus and pulmonary artery were occluded leaving the animal dependent on the reperfused lung (control, n = 6). Pulmonary function was assessed by alveolo-arterial oxygen difference (AaDO2) and pulmonary vascular resistance (PVR), the chemiluminescence of isolated neutrophils, as well as the release of beta-N-acetyl-glucosaminidase (beta-NAG) served as indicator of neutrophilic activation. Extravascular lung water was an indicator for pulmonary edema formation. EL-246 group animals (n = 6) were treated additionally with 1 mg/kg BW of EL-246 given prior and during reperfusion. RESULTS: After 3 h of reperfusion five control animals developed alveolar edema compared to one animal in the EL-246 group (P = 0.08). AaDO2 (mm Hg) was significantly higher in the control compared to the EL-246 group (510 +/- 148 vs. 214 +/- 86). PVR (dyn x s x cm(-5)) was significantly increased in the control compared to the EL-246 group (656 +/- 240 vs. 317 +/- 87). Neutrophilic activation was significantly lower in the EL-246 group. Extravascular lung water was significantly lower compared to control (6.88 +/- 1.0 vs. 13.4 +/- 2.8 g/g blood-free lung weight). CONCLUSIONS: Treatment with EL-246 results in improved pulmonary function and less in vivo PMN activation in this experimental model. Further studies are necessary to evaluate the possible role of selectin blockade in amelioration of reperfusion injury in human lung transplantation.

Acetylglucosaminidase↗

PubMed1999

Effect of freeze-thawing procedure on chromatin stability, morphological alteration and membrane integrity of human spermatozoa in fertile and subfertile men.

Cryopreservation is known to impair sperm motility and decrease the fertilization rate by detrimental effects on acrosomal structure and acrosin activity. However, the consequences of cryopreservation on the integrity of the sperm nucleus, chromatin stability and centrosome are less clear. The present study was designed to determine the effect of the freeze-thawing procedure on chromatin condensation (aniline blue staining) and the morphology (strict criteria) and membrane integrity of human spermatozoa. The structural and functional characteristics of the sperm plasma membrane were measured by the eosin-test and hypo-osmotic swelling test which were done separately. Sperm cryopreservation was performed on semen samples from two groups of men classified as fertile (n = 20) and subfertile (n = 72), based on their reproductive history and semen analysis according to WHO guidelines. The mean percentage of condensed chromatin, morphologically normal spermatozoa and membrane integrity in all semen samples investigated (n = 92) decreased significantly (p = 0.0001) after freeze-thawing, in comparison to the value observed prior to freezing. By comparing the semen samples between fertile and subfertile patients, significantly (p = 0.0009) greater damage was demonstrated in the subfertile than in the fertile group. Furthermore, no significant difference was observed between the two groups with regard to the morphological alteration and structural as well as functional damage of the sperm membrane. In conclusion, the freeze-thawing procedure significantly affects chromatin structure and sperm morphology, especially in the head and the tail regions, and this may explain the lower fertilization rate and IVF/ICSI outcome when frozen-thawed spermatozoa are used. In addition, this study demonstrates that chromatin condensation is a sensitive parameter for the evaluation of cryodamage of semen samples from fertile and subfertile patients, though subfertile patients with very poor semen characteristics have yet to be studied. It is therefore recommended that chromatin condensation be used as an additional parameter for the assessment of sperm quality after freeze-thawing.

Cell Membrane↗

PubMed1997

[Status of alimentary iodine supply in the Potsdam area].

In the period from November 1995 to April 1996 we have collected 120 samples of 24-h-urine from volunteers of the "Brandenburger Ernährungs- und Krebsstudie". 108 persons--without iodine supplementation--showed an average iodine excretion about 99 micrograms I/g creatinine, and the median value showed 94.2. Only 45.4% of the samples indicated a sufficient iodine supply. In 43.5% an iodine deficiency grade I was registered, and in 11.1% grade II. An iodine deficiency grade III did not occur. Due to the increased use of iodized salt in meat- and cereal products, to intensive public education etc. it seems, that the individual iodine intake is better than some years ago. But the iodine deficiency prophylaxis should be further more continued.

Adult↗

PubMed1997

Interviewer variability in anthropometric measurements and estimates of body composition.

OBJECTIVE: The extent of intra- and inter-interviewer variability both in anthropometric measurements and in estimates of body composition was assessed and the possibility of systematic variation due to interviewer differences investigated. DESIGN AND SUBJECTS: Seventeen interviewers trained in the anthropometric measurement technique and 10 healthy volunteers (4 men, 6 women) participated in the study on measurement variability. To ensure participation of all interviewers the study was carried out on three different days. On each of these days interviewers got randomly allocated to the subjects being present. Each interviewer took 12 measurements--body weight, body height, sitting height, circumferences of waist, hip, and midarm, skinfolds (biceps, triceps, subscapular, and suprailiac), chest breath and depth--per subject on two occasions. From these measurements, body mass index, waist-to-hip ratio, percentage of body fat, fat mass, fat free mass and metric index were determined. For all anthropometric variables variance components, reliability coefficients (R) and coefficients of variation (CV) were estimated and systematic differences of measurements between interviewers were assessed. RESULTS: Measurement reliability in basic anthropometric measures expressed as variance components, reliability coefficients and coefficients of variation was influenced to a greater extent by inter-interviewer variability (R: 0.858-0.999; CV: 0.1-20.9) than intra-interviewer variability (R: 0.979-0.999; CV: 0.0-6.4). The respective estimates of body composition exhibited comparatively higher reliability (Rinter: 0.975-0.999; Rintra: 0.995-0.999). Measurements more prone to subjectivity, e.g. skinfolds showed lower reliability (CVinter: 9.3-20.9; CVintra: 3.6-6.4). Although the absolute variation in measures due to interviewers was small, systematic differences among interviewers were clearly evident in all measurements and estimates except sitting height in this group of subjects. CONCLUSION: Anthropometric measures and estimates of body composition obtained in the current study show the feasibility of detailed anthropometric data collection by multiple interviewers in large-scale epidemiological studies.

Adult↗

PubMed1995

[Assessment of individual iodine intake by the adult population in the Potsdam region on the basis of sea fish and iodized salt consumption].

Iodized salt has a high acceptance in the Potsdam region: 82% of the interviewed people use iodized salt, 13% do not use it, and only 5% of the probands were not able to make any statements. The current average iodine intake for adults is 76 micrograms/day. Only 5% of the adult population has an iodine intake of more than 100 micrograms/day. An efficient elimination of iodine deficiency in Germany requires a broad usage of iodized salt in the food industry.

Adult↗

PubMedDate not supplied

Gamma-hydroxybutyrate versus chlorprothixene/phenobarbital sedation in children undergoing MRI studies.

BACKGROUND: Few clinical studies have assessed gamma-hydroxybutyrate and chlorprothixene/phenobarbital sedation in children. This prospective trial compared the two regimes in children, in particular concerning differences in recovery time. METHODS: 28 pediatric oncology patients undergoing elective MRI studies at a university hospital were randomly assigned to either receive gamma-hydroxybutyrate or chlorprothixene/phenobarbital sedation. Time to induce deep sedation (Ramsay score of 5) and recovery time, the incidence of failure of sedation, the frequency of side effects, the need for therapeutic interventions, and the number of patients receiving additional midazolam were recorded. Analysis of hemodynamic parameters was performed at five defined time points. RESULTS: All 28 MRI studies were successfully completed. Recovery time was significantly shorter with gamma-hydroxybutyrate (p < 0.01). There were more side effects with chlorprothixene/phenobarbital, in particular tachycardia and hyperexcitation. Vomiting was the side effect most often seen in gamma-hydroxybutyrate sedation. Therapeutic interventions were not required in any patient. Additional midazolam was necessary to maintain satisfactory sedation in six children receiving gamma-hydroxybutyrate and four receiving chlorprothixene/phenobarbital. CONCLUSIONS: Due to its significantly shorter recovery time, gamma-hydroxybutyrate is a reasonable sedative drug for children undergoing non-invasive diagnostic procedures, and is superior to chlorprothixene/phenobarbital. In pediatric oncology patients gamma-hydroxybutyrate appears to be associated more often with vomiting. The long recovery time and its great variability make chlorprothixene/phenobarbital a less valuable alternative.

Adolescent↗

PubMedDate not supplied

[Primary stability of 2 PLIF (posterior lumbar interbody fusion)--a biomechanical in vitro comparison].

OBJECTIVE: The purpose of this biomechanical in-vitro-study was to compare two different PLIF-techniques with two types of implants on human lumbar spine: PLIF with threaded cages, (Bagby and Kuslich, Spinetech, Minneapolis, USA) and PLIF with the Moss-Miami-implants, (DePuy International Limited, Leeds, Great Britain). METHODS: Six cadaveric human lumbar spine segments L2-5 were explanted, frozen at -20 degrees C and thawed before preparation. They were cut in two parts by discectomie and arthrotomie L3/4, so six specimen L2/3 and six specimen L4/5 were obtained and used in a crossover-trial. Analysis included testing in a tension-torsion-machine under axial compression with 600 N, rotation (left-right) with 25 Nm and shearing forces with 250 N without preload. This was first done in the intact and then in the fused specimen. RESULTS: Stiffness before treatment was comparable in both groups irrespective of location. Posttreatment stiffness was higher with MOSS-MIAMI-implants as compared to PLIF with BAK-cages. Average relative superiority (and 95%-confidence intervall) were 1.98 (1.01-3.69) for compression, 2.30 (0.85-6.24) for rotation and 1.73 (0.78-3.84) for shearing. Statistical comparison of log posttreatment stiffness was significant for compression but not for rotation and shearing (2-sided independent crossover t-test). CONCLUSION: This biomechanical in-vitro-study demonstrates the higher initial stability of PLIF with titanium surgical mesh and posterior instrumentation when compared to PLIF with threaded cages alone.

Biomechanical Phenomena↗

PubMedDate not supplied

Sperm morphology and chromatin condensation before and after semen processing.

Semen analysis constitutes the most important investigation of male infertility. However, the true anomalies present in defective sperm cells have been only partially characterized. The integrity of the sperm chromatin may play the most important role, particularly in ICSI, where most of the natural selection mechanisms are bypassed. This study was carried out to characterize sperm morphology (strict criteria), to evaluate chromatin condensation and sperm count in native semen as well as after semen preparation by the swim-up technique, and to eventually evaluate any correlation between these parameters. Semen from 90 men was analyzed for the above parameters in both the fresh and processed semen. Whereas the sperm count decreased after sperm preparation by the swim-up technique in comparison to the value in the fresh semen (p < .001), there was an increase in the percentage of morphologically normal (p < .001) and chromatin-condensed sperm (p = .99). However, there was no correlation between sperm morphology, chromatin condensation, and sperm count either in the fresh or in the processed semen samples. These results suggest that sperm morphology, sperm count, and chromatin condensation are independent parameters that should be evaluated separately in the assessment of male fertility in an assisted reproduction program.

Chromatin↗

PubMedDate not supplied

Predictive value of sperm chromatin condensation (aniline blue staining) in the assessment of male fertility.

A case control study was carried out to determine the value of sperm chromatin condensation in the assessment of male fertility. A total of 165 semen samples from 90 patients (cases) and 75 healthy donors (control) were examined for chromatin condensation (aniline blue staining), as well as conventional sperm parameters, notably sperm morphology, sperm count, and progressive motility. Whereas only 55 +/- 12.0% of the samples from the infertile patients were unstained by aniline blue (chromatin condensed), 78 +/- 19.0% of the samples in the control group did not take up the stain (chromatin condensed). A significant difference (p < .001) was observed between the two groups. Similarly, the difference between the mean percentage of morphologically normal spermatozoa for the infertile patients (12.1 +/- 1.2%) and the control (23.9 +/- 1.9%) was very significant (p < .001). In addition, only 50 out of the 90 patients (55.5%) had a normal sperm count, whereas all the 75 (100%) were normal in the control group. By comparing between the two groups a significant difference (p < .001) was also observed. Furthermore, a significant difference (p < .001) was also found between the cases and the control with regard to the percentage of spermatozoa illustrating linear progressive motility (40 +/- 9.7% vs. 70 +/- 12.3%). However, no correlation was found between sperm chromatin condensation and morphology, count, and motility. This study suggests that chromatin condensation constitutes a valuable parameter in the assessment of male fertility, completely independent of conventional sperm parameters. Consequently, the inclusion of chromatin condensation to routine laboratory investigations of semen prior to assisted reproduction is strongly recommended.

Adult↗