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Biomedical subjects

D Schneider

Publications and source records attributed to D Schneider.

At least 109 records · Page 6Linked to original sources
PubMed1999

The selenoprotein thioredoxin reductase is expressed in peripheral blood monocytes and THP1 human myeloid leukemia cells--regulation by 1,25-dihydroxyvitamin D3 and selenite.

1,25(OH)2 Vitamin D3 (1,25(OH)2D3) and adhesion propagate monocyte differentiation. We identified the selenoprotein thioredoxin reductase (TrxR) as a new molecular target for 1,25(OH)2D3 in monocytes during this process. In THP1 monocytic leukemia cells 1,25(OH)2D3 stimulated TrxR mRNA levels 2-4-fold by 4-8 h and enhanced TrxR activity (60%) (as measured by the dithionitrobenzole-assay) after 24 h, which declined below baseline after 96 h. The addition of 100 nM selenite enhanced (approx. 50%) basal and stimulated enzyme activity in THP1 cells. The relative stimulation by 1,25(OH)2D3 was very similar but peak levels were sustained in THP1 cells up to 48 h. Human peripheral blood monocytes (PBM) of different donors showed very low basal TrxR steady state mRNA levels which were markedly enhanced (as analyzed by Northern blotting) after 4 h of adherence to culture dishes. 1,25(OH)2D3 (100 nM) further stimulated TrxR mRNA expression (4 h, 3-fold). TrxR enzyme activity mirrored the mRNA changes. Basal activity was stimulated approx. 25% by adhesion in culture alone and was further stimulated (approximately 15%) by 1,25(OH)2D3 after 4 h. By 24 h similar results were achieved but the effect of 1,25(OH)2D3 could be seen in the presence of 100 nM selenium only. The expression of TrxR and its regulation by 1,25(OH)2D3 and selenite in monocytes might be important for their induction of differentiation and maintenance of function.

Calcitriol↗
PubMed1999

Schistosoma bovis: vaccine effects of a recombinant homologous glutathione S-transferase in sheep.

The economic importance of the trematode Schistosoma bovis in African livestock has justified the development of a specific vaccine. Administered preventively to sheep, rSb28GST--the only molecule cloned from S. bovis which has demonstrated vaccine potentialities in goats and cattle--reduced the mean worm burden in vaccinated animals and improved their health status compared with that of non-vaccinated controls. As in goats, but not in bovines, the fecundity of the settled worm pairs was not modified. Therefore, rSb28GST can be proposed as a universal tool for the prevention of clinical disorders engendered by the main schistosome species affecting domestic ruminants in the African continent.

Animals↗
PubMed1999

Ageing of the cardiovascular system during 33 years of aerobic exercise.

BACKGROUND: increasing age affects aerobic capacity, with an average loss of 10% or more per decade. AIM: to determine the effect of ageing on the circulatory system in middle-aged men during 33 years of physical training. METHODS: 15 men initially aged 45 years took part in an exercise training programme for 25-33 years. Nine serial measurements were made at rest and during maximal effort. Aerobic training consisted of swimming, jogging, walking and cycling 3-4 times per week. Sessions were for 61-70 min at 77-84% of heart rate reserve. RESULTS: there was no change in resting heart rate, blood pressure, percentage fat or body composition. Minimal cardiovascular losses at maximal work included 5.8-6.8% in maximal oxygen uptake per decade, 25 beats in maximum heart rate and 26 beats in heart rate reserve. CONCLUSION: exercise training has a favourable effect on ageing of the cardiovascular system in older men, resulting in minimal loss of oxygen uptake, no rise in resting blood pressure and no change in body composition.

Adult↗
PubMed1999

The level of human decidua-associated protein (hDP) 200, identified as a monoclonal rheumatoid factor in the fallopian tube.

PROBLEM: The aim of this study was to examine whether ectopic pregnancy is associated with increased levels of human decidua-associated protein (hDP) 200, identified as a monoclonal rheumatoid factor, in the related fallopian tube as compared with normal tubes. METHOD OF STUDY: Tubal fluid samples were obtained prospectively from two groups of patients: group I, 20 patients admitted for total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH and BSO); group II, 14 women with ectopic pregnancy, undergoing unilateral salpingectomy by laparoscopy or laparotomy. hDP 200 was assayed using double-site enzyme-linked immunosorbent assay. RESULTS: Very low levels of hDP 200 were found in normal tubes, while tubes with ectopic pregnancy demonstrated significantly higher levels of tubal fluid hDP 200 (P < 0.00001). In addition, in women with ectopic pregnancy, the uterine fluid level of hDP 200 was significantly lower than the level of hDP 200 in the tube containing ectopic pregnancy (P < 0.0001). CONCLUSION: The increased level of hDP 200 (a monoclonal rheumatoid factor) in the tube containing ectopic pregnancy, as compared with uterine cavity and normal tubes, might be associated with the implantation site of the pregnancy.

Adult↗
PubMed1999

Extracorporeal rheopheresis in the treatment of acute ischemic stroke: A randomized pilot study.

BACKGROUND AND PURPOSE: Extracorporeal rheopheresis is a safe method to optimize hemorheology. Our aim was to determine whether treatment with extracorporeal rheopheresis in patients with acute ischemic hemispheric stroke improves cerebral perfusion as assessed with serial 99mTc-ethyl-cysteinate-dimer single-photon emission CT (99mTc-ECD SPECT). We also investigated how clinical outcome is associated with treatment and imaging results. METHODS: Thirty-three patients (mean age, 64+/-10 years) with acute ischemic hemispheric stroke were included in a prospective, randomized, parallel group pilot study. First treatment with or without extracorporeal rheopheresis took place within 12 hours after the onset of symptoms and was repeated 3 times at intervals of 24 hours. Hemorheological parameters were measured before and after each session. Each patient underwent 99mTc-ECD SPECT immediately before treatment, 6 to 8 hours after treatment, and after 5 days. A semiquantitative SPECT graded scale was used to measure depth and extent of activity deficits and thus to quantify the perfusion deficit. RESULTS: Seventeen patients were actively treated with extracorporeal rheopheresis, and 16 patients did not receive extracorporeal rheopheresis. After 3 months, no differences were found in the functional or neurological outcome. Despite a rapid, sustained decrease of plasma viscosity and erythrocyte aggregation in the rheopheresis group, there was no significant difference in the SPECT graded scale after therapy between the 2 groups. Patients with early reperfusion (decrease in the SPECT graded scale >25% 6 to 8 hours after therapy compared with the baseline examination) experienced a better functional outcome (Modified Rankin Scale) after 3 months compared with patients without reperfusion (P=0.04). CONCLUSIONS: Since quantitative flow mapping and clinical follow-up did not reveal any differences between patients who were treated with extracorporeal rheopheresis and controls, it appears very unlikely that extracorporeal rheopheresis enhances reperfusion after acute cerebral ischemia.

Acute Disease↗
PubMed1999

Chemotherapy and thrombosis in gynecologic malignancy.

Thromboembolism is a severe and frequent problem in gynecologic malignancy. The average DVT incidence during chemotherapy of 5% might represent the lower range of incidence because < 55% of thrombotic complication manifest clinical signs. However, it seems likely that in addition to chemotherapy other risk factors such as menopausal status, BMI of patients, or type of preceding surgery must coincide before thrombosis manifests. While monitoring of patients using sophisticated coagulation tests did not identify patients' risk for DVT during chemotherapy, an evaluation of the coagulation status before initiating chemotherapy is recommended. Patients with a venous access device (e.g., indwelling central venous catheter or with port cart) are at a particularly high risk for DVT. This has to be considered when cytoreductive therapy is given. Thrombosis prophylaxis, orally or subcutaneously, should only be considered in a subpopulation of patients who offer a combination of the aforementioned risk factors. Thrombosis prevention trials during chemotherapy found a significant reduction of DVT in patients treated with anticoagulants.

Antineoplastic Agents↗
PubMed1999

Enhancement by glucose of low density lipoprotein-oxidation by peroxynitrite.

Oxidation of low density lipoprotein (LDL) by copper ions is not influenced by glucose in a concentration range between 1 and 20 mM. LDL-oxidation by peroxynitrite or the simultaneous action of nitrogen monoxide and superoxide, produced by morpholino-sydnonimine (SIN-1) is considerably enhanced by typical hydroxyl-radical scavengers such as formate or mannitol and by glucose. Since both free radicals, nitrogen monoxide and superoxide, are produced by activated leukocytes and endothelial cells the presented reaction might represent a simple model for the cooperative function of reactive oxygen species (ROS) and glucose in certain diabetic blood vessel diseases such as atherogenesis and retinopathy.

Glucose↗
PubMed1999

Androconial hairbrushes of the Syntomis (Amata) phegea (L.) group (Lepidoptera, Ctenuchinae): a synapomorphic character supported by sequence data of the mitochondrial 16S rRNA gene.

Males of several palaearctic Syntomis/Amata species (Lepidoptera: Arctiidae) possess androconial hairbrushes in connection with the foreleg coxa. The cuticular structure of these potentially behaviour-related and pheromone dissipating brushes is described. Such male-specific organs and signals play a crucial role in the female choice procedure. The presence of hairbrushes was found in 17 out of 28 inspected species of the tribe Syntomini. All members of the Syntomis phegea group (Europe to Central Asia, as well as Caspian, Caucasian and near-middle East species) have these structures, and only three oriental and south Asian, but none of three African species, carry this trait. The common genetic base of this morphological character is supported by an analysis of mitochondrial 16S rRNA from 19 representative taxa; species with hairbrushes form a monophyletic clade and the brushes are a synapomorphic character. This genetic finding corroborates the ethological significance of these organs. Phylogenetic data show a substantial genetic divergence between the tribe Ctenuchini (New World species) and the Old World Syntomini. Furthermore, DNA sequence data suggest a split of the genus Amata (sensu Obraztsov, 1966) in two distinct genera, Amata (without hairbrushes) and Syntomis (with hairbrushes).

Animals↗
PubMed1999

Studies on the chemical identity and biological functions of pangamic acid.

Pangamic acid (6-O-(dimethylaminoacetyl)-D-gluconic acid) has been detected 1938 and described as a natural, universally occurring substance with multiple biological and medical functions. In this respect pangamic acid has been worldwide on the market since decades as a drug stimulating cellular respiration. In addition to the natural pangamic acid, diisopropylammonium dichloroacetate (DIPA), a synthetic product not found in biological material, is on the market requesting similar biological functions. In commercially available drugs on the German market declared as pangamic acid three separate substances can be found by chemical identification of pangamic acid, namely: gluconic acid, glycine and diisopropylamonium dichloroacetate. As biological functions have been found in vitro inhibition of Cu-dependent LDL oxidation by glycine due to chelation of Cu2+ ions and deterioration of mitochondrial respiratory control due to an increased state IV oxygen consumption rate at high concentrations of DIPA.

Animals↗
PubMed1999

The oral route as a potential way of transmission of Schistosoma bovis in goats.

The infectivity of Schistosoma bovis cercariae administered orally was evaluated in Sahelian goats. Compared to the percutaneous route, a single massive oral dose resulted in a worm burden and in fecal egg excretion reduced by one-half. Surprisingly, tissue egg counts were increased by more than 4-fold. Fecundity of individual female schistosomes was, therefore, markedly increased. When infective doses were administered weekly for 20 wk, both worm and egg burdens were doubled without modification of the individual worm pair fecundity. Repeated oral infections seem to have induced an acquired tolerance toward parasite antigens. These results confirm the epidemiologic relevance of the oral route in a host species inclined to become infected through drinking water rather than percutaneous exposures.

Administration, Oral↗
PubMed1999

Peritoneal fluid analysis in the differentiation of ovarian cancer and benign ovarian tumor.

PURPOSE: The aim of the study was to try to identify the biochemical markers in peritoneal fluid which might be useful in discrimination between ovarian cancer and benign ovarian tumor. METHODS: The study included 75 patients: 43 with invasive ovarian cancer, 6 with borderline ovarian cancer and 26 with benign ovarian tumor. The peritoneal fluid samples from all these patients were subjected to cytologic examination and to analysis of lactate dehydrogenase (LDH), total protein, albumin and cholesterol. In addition, peritoneal fluid to serum ratio of LDH and total protein, as well as serum CA-125 were assayed. The biochemical parameters were compared between cases of ovarian cancer and cases of benign ovarian tumor, as well as between the different histological types and stages of ovarian cancer. RESULTS: All the examined parameters demonstrated a significant difference comparing patients with ovarian cancer and those with benign ovarian tumor (p<0.001). Yet, the greatest diagnostic accuracy was achieved by measuring peritoneal fluid LDH (86%) and cholesterol (93%). Moreover, significant differences in the level of assayed parameters were found when comparing different histological types and stages of ovarian cancer. In order to further corroborate the diagnostic performance, we combined the parameters of LDH and cholesterol with cytology, thus increasing the diagnostic accuracy to 96%. CONCLUSION: The association of peritoneal fluid LDH and cholesterol may represent a primary tool for the discrimination of patients with ovarian cancer (even borderline) from those with benign ovarian tumor, particularly in the presence of negative cytology.

Adult↗
PubMed1999

Infections and melanoma risk: results of a multicentre EORTC case-control study. European Organization for Research and Treatment of Cancer.

Immune function plays a prominent role in the defence against cutaneous malignant melanoma and the increased risk of melanoma development during immunosuppression. Since the immune system is challenged beyond its routine activity by an infection, the effect of previous infectious diseases on the risk of melanoma may also be crucial. In a European Organization for Research and Treatment of Cancer (EORTC) case-control study performed in six European countries and Israel, we compared the history of severe infections in 603 melanoma patients with that in 627 population controls. We calculated adjusted odds ratios (ORs) to estimate the effect of infectious diseases on melanoma risk. The ORs for melanoma risk were below 1 for nearly all types of infections (except two) if body temperature was not taken into consideration, and for all infections with a body temperature above 38.5 degrees C. In the latter category significantly lowered ORs were found for pulmonary tuberculosis (0.16; 95% confidence interval [CI] 0.01-0.98), Staphylococcus aureus infections (0.54; 95% CI 0.31-0.94), sepsis (0.23; 95% CI 0.06-0.70), influenza and related infections (0.65; 95% CI 0.48-0.86) and pneumonia (0.45; 95% CI 0.27-0.73). Analysis of the cumulative influence revealed a consistent pattern of results pointing to a reduction in melanoma risk with increasing numbers of recorded infections and fever height. This apparent dose-response relationship suggests a causal association. Speculations on the underlying mechanism include a Shwartzman-like phenomenon when melanoma formation precedes the infection and/or an infection-related Th1-cell activation preventing the establishment of the tumour.

Adult↗
PubMed1999

Genome-wide screen for atopy susceptibility alleles in the Hutterites.

A genome-wide screen for loci influencing positive skin prick tests (SPT) to airborne allergens was conducted in the Hutterites, a founder population of European ancestry. Positive SPT to 14 standardized allergens was measured in 370 subjects in our primary sample and 324 subjects in a replication sample. Evidence for linkage to positive SPT was assessed using the transmission disequilibrium test (TDT) with 337 autosomal markers (average spacing 9.13 cM, SD = 7.8 cM). Three loci showed the strongest overall evidence of linkage to atopy, with at least one allele-specific and a locus-specific p< 1 x 10(-4). This study provides evidence for at least three atopy-susceptibility loci in the Hutterites on chromosomes 1, 6 and 16.

Adult↗
PubMed1998

Randomised double-blind placebo-controlled trial of thrombolytic therapy with intravenous alteplase in acute ischaemic stroke (ECASS II). Second European-Australasian Acute Stroke Study Investigators.

BACKGROUND: Thrombolysis for acute ischaemic stroke has been investigated in several clinical trials, with variable results. We have assessed the safety and efficacy of intravenous thrombolysis with alteplase (0.9 mg/kg bodyweight) within 6 h of stroke onset. METHODS: This non-angiographic, randomised, double-blind, trial enrolled 800 patients in Europe, Australia, and New Zealand. Computed tomography was used to exclude patients with signs of major infarction. Alteplase (n=409) and placebo (n=391) were randomly assigned with stratification for time since symptom onset (0-3 h or 3-6 h). The primary endpoint was the modified Rankin scale (mRS) at 90 days, dichotomised for favourable (score 0-1) and unfavourable (score 2-6) outcome. Analyses were by intention to treat. FINDINGS: 165 (40.3%) alteplase-group patients and 143 (36.6%) placebo-group patients had favourable mRS outcomes (absolute difference 3.7%, p=0.277). In a posthoc analysis of mRS scores dichotomised for death or dependency, 222 (54.3%) alteplase-group and 180 (46.0%) placebo-group patients had favourable outcomes (score 0-2; absolute difference 8.3%, p=0.024). Treatment differences were similar whether patients were treated within 3 h or 3-6 h. 85 (10.6%) patients died, with no difference between treatment groups at day 90+/-14 days (43 alteplase, 42 placebo). Symptomatic intracranial haemorrhage occurred in 36 (8.8%) alteplase-group patients and 13 (3.4%) placebo-group patients. INTERPRETATION: The results do not confirm a statistical benefit for alteplase. However, we believe the trend towards efficacy should be interpreted in the light of evidence from previous trials. Despite the increased risk of intracranial haemorrhage, thrombolysis with alteplase at a dose of 0.9 mg/kg in selected patients may lead to a clinically relevant improvement in outcome.

Adolescent↗
PubMed1998

Radiotherapy of bladder cancer: relevance of bladder volume changes in planning boost treatment.

PURPOSE: This study aims to evaluate tumor motion with controlled changes of the bladder volume, and to assess the reproducibility of bladder (and tumor) position using a urinary catheter balloon as an immobilization device. METHODS AND MATERIALS: First, three patients with tumor growths in three different bladder regions (trigone, left lateral wall, anterior wall) were evaluated. Three-dimensional CT-based reconstructed images were used to measure the displacement of the tumors when 100 cc were removed from a bladder originally filled with 170 cc of contrast. The 3D calculated boost beam arrangements and field sizes for the three tumors in the partially emptied bladders were used to simulate treatment of the same tumors in the maximally filled bladders. Dose-volume histograms were obtained. Second, verification of an ellipsoid model for bladder volume changes was undertaken in 41 patients. Third, in eight additional patients a urinary catheter balloon filled with 80-cc sterile saline solution was used in an attempt to reproduce the shape and spatial coordinates of the bladder during the boost treatment. A pair of orthogonal films with the 80-cc balloon filled with contrast material were taken at simulation and repeated twice at weekly intervals during radiotherapy. The reproducibility was quantified by sequentially calculating the common surface of the bladder images in each orthogonal view. RESULTS: Target motion, especially in the craniocaudal axis, appeared to be more relevant for tumors arising in the bladder walls (15 mm) than in the trigone (5 mm). Underdosage (<95% of the prescribed dose to the target volume) was observed in 20, 20, and 50% (with 1 cm margins around the tumor) and in 10, 10, and 15% (with 1.5 cm margins around the tumor) of the tumors arising in the trigone, left lateral wall, and anterior wall, respectively. The ellipsoidal model was validated with a strong correlation coefficient allowing to establish a predictive model for bladder wall displacements as a function of bladder volume. In the balloon reproducibility study, mean reproducibility factors of 0.84 (+/-0.06) and 0.82 (+/-0.07) were obtained for both anteroposterior and lateral views, respectively. CONCLUSIONS: Changes in bladder volume and shape related to bladder filling can result in clinically significant displacements of the target volume. A minimum of 2-cm margins around the target may compensate for extreme bladder volume changes during boost treatment. An ellipsoidal model for the bladder is consistent with these observations. Although an 80-cc urinary catheter balloon helped to immobilize the bladder, reproducibility was less than perfect.

Humans↗