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Biomedical subjects

C Schulz

Publications and source records attributed to C Schulz.

At least 37 records · Page 2Linked to original sources
PubMed2000

RANTES in the postoperative course after liver transplantation.

RANTES (regulated upon activation, normal T-cell expressed and secreted), an inflammatory cytokine, promotes accumulation and activation of leukocytes. In 67 liver transplantations, systemic concentrations of RANTES were correlated to graft survival and incidence of rejection. RANTES levels either increased to highly elevated levels at day 14 (84 +/- 64 ng/ml; group 1; n = 43) or remained within the limit of healthy controls (19 +/- 11 ng/ml at day 14; group 2; n = 24). The 100-day graft function rate was 0.91 in group 1 and 0.63 in group 2 (P = 0.002). The risk ratio for rejection during the first 100 days was increased 2.2-fold in group 2 compared to group 1 (P = 0.02). High postoperative release of RANTES after liver transplantation, a beneficial factor, may reflect a general systemic immunological activation. It can be concluded that high early systemic RANTES levels may play a role in immunological recognition leading to a tolerance of the liver graft.

Adolescent↗
PubMed2000

Tay's syndrome: MRI.

Tay's syndrome is a trichothiodystrophy associated with congenital ichthyosis. We report the findings on MRI and spectroscopy in a young girl with sparse, short, ruffled hair, dry skin and delayed milestones. T2-weighted images showed prominent diffuse confluent increase in signal symmetrically in all the supratentorial white matter. These findings are similar to those in a previously described case, and consistent with dysmyelination. Spectroscopy showed increased myoinositol and decreased choline.

Brain↗
PubMed2000

Coronary stent symmetry and vascular injury determine experimental restenosis.

OBJECTIVE: To assess the impact of stent symmetry on restenosis using the coronary overstretch sheep model. METHODS: Neointimal thickness, injury index, and percentage diameter and area stenosis were calculated by digital morphometry. The standard deviation of the angular burden was used to assess stent symmetry for each section. MATERIALS: 15 healthy Merino sheep (63-75 kg) underwent implantation of 30 slotted tube stents (7 mm). Restenosis was induced by calculated overstretch of the coronary artery. Twenty eight days after implantation, stents were excised and underwent histological examination using quantitative digital morphometry. RESULTS: The severity of vessel injury was positively correlated with neointimal thickness and with percentage diameter and area stenosis (p < 0.001). Mean neointimal thickness and mean vascular injury per cross section were strongly related to the standard deviation of angular burden, with correlation coefficients of 0.6 and 0.8, respectively (p < 0.001). CONCLUSIONS: The well known relation between vascular injury and restenosis was confirmed, and a new relation was discovered between stent asymmetry and restenosis. If these results apply to human coronary arteries, restenosis may also be dependent on the degree of asymmetric stent expansion. These results should influence the development of new stent designs to reduce asymmetric stent expansion, leading to a more homogeneous strain distribution in stented coronary segments.

Angioplasty, Balloon, Coronary↗
PubMed2000

Lithium-induced EEG changes in patients with affective disorders.

In 12 patients with affective disorders (ICD-10: F31, F32, F33), EEGs were recorded before and after 4.4 months of lithium treatment. Effects of lithium on the EEG were analyzed by power spectral analysis controlled for vigilance. We found (1) an increase in relative power in both delta and theta band which was related to the lithium plasma level, (2) a decrease in relative alpha power especially at occipital leads and (3) a reduction of the dominant alpha frequency. The changes in relative power were more pronounced in the right hemisphere, which is in contrast to the hypothesis of a site-specific localization of lithium effects only in left anterior regions.

Aged↗
PubMed2000

Heterodimeric versus homodimeric structure of the primary electron donor in Rhodobacter sphaeroides reaction centers genetically modified at position M202.

Using light-induced Fourier-transform infrared (FTIR) difference spectroscopy of the photo-oxidation of the primary donor (P) in chromatophores from Rhodobacter sphaeroides, we examined a series of site-directed mutants with His M202 changed to Gly, Ser, Cys, Asn or Glu in order to assess the ability of these side chains to ligate the Mg atom of one of the two bacteriochlorophylls (BChl) constituting P. In the P+QA-/PQA FTIR difference spectra of the mutants HG(M202), HS(M202), HC(M202) and HN(M202), the presence of a specific electronic transition at approximately 2650-2750 cm-1 as well as of associated vibrational (phase-phonon) bands at approximately 1560, 1480 and 1290 cm-1 demonstrate that these mutants contain a BChl/BChl homodimer like that in native reaction centers with the charge on P+ shared between the two coupled BChl. In contrast, the absence of all of these bands in HE(M202) shows that this mutant contains a BChl/bacteriopheophytin heterodimer with the charge localized on the single BChl, as previously determined for the mutant HL(M202). Furthermore, the spectra of the heterodimers HE(M202) and HL(M202) are very similar in the 4000-1200 cm-1 IR range. Perturbations of the 10a-ester and 9-keto carbonyl modes for both the P and P+ states are observed in the homodimer mutants reflecting slight variations in the conformation and/or in position of P. These perturbations are likely to be due to a repositioning of the dimer in the new protein cavity generated by the mutation.

Dimerization↗
PubMed2000

Expression of a retinoid-inducible tumor suppressor, Tazarotene-inducible gene-3, is decreased in psoriasis and skin cancer.

Tazarotene-induced gene-3 (TIG-3), isolated from human keratinocytes treated with the retinoic acid receptor-selective retinoid Tazarotene, is homologous to H-rev, a class II tumor suppressor. TIG-3 gene localized to chromosome 11q23, a site of loss of heterozygosity in several malignancies. Retinoids influence epidermal differentiation and are used to treat and prevent skin cancer. Therefore, we studied TIG-3 mRNA expression in psoriasis and in basal and SCCs by in situ hybridization and a quantitative QT-RT-PCR assay. Psoriasis lesions had significantly lower staining (median, 3) than paired normal control skin (median, 4; P = 0.012). TIG-3 mRNA was significantly higher in normal control skin (P = 0.001), in paired adjacent skin (median, 3; P = 0.007), and in overlying epidermis (median, 3.0; P = 0.0001) than in 21 SCC specimens as a group (median, 1.5).

Aged↗
PubMed1999

[Evaluation of preoperative functional status in patients with lung cancer].

In view of the dismal prognosis of unresected bronchial cancer, surgical resection should be encouraged even in patients with borderline cardiopulmonary function. Accurate estimation of the cardiopulmonary reserve is therefore desirable to avoid denying potentially curative treatment on the on hand and severe postoperative disability on the other. Various parameters (lung volumes, gas exchange, pulmonary hemodynamics, exercise endurance) are reviewed concerning their predictive values to evaluate functional operatibility. No ideal test exists. During exercise both pulmonary and cardiac risk can be evaluated simultaneously. The high predictive value of maximal oxygen uptake to assess postoperative morbidity and mortality is established. The postoperative values for the forced expiratory volumes, the transfer factor, and maximal oxygen uptake can be predicted by means of quantitative lung scans. A new four-stage algorithm for the functional evaluation is presented. Patients with normal lung function and exercise electrocardiography can undergo lung resection up to a pneumonectomy without further diagnostic procedures. In others, first the predicted postoperative values of forced expiratory volume and transfer factor should be estimated by taking into account the number of segments to be resected. Patients with values < 30% predicted are regarded as inoperable, whereas values > 40% predicted quality for resection without the need for further diagnostics. Patients with values between 30-40% predicted are further differentiated with cardiopulmonary exercise testing and for those cases where diagnostic uncertainty still remains, predicted postoperative values can be calculated using quantitative lung scans.

Carcinoma, Bronchogenic↗
PubMed1999

[Risk assessment of patients before lung surgery].

Lung resection offers the best prospect of long-term survival in patients with nonmetastatic pulmonary neoplasia. In view of the dismal prognosis of unresected bronchial cancer, surgical resection should be encouraged even in patients with reduced cardiopulmonary function. Accurate estimation of the postoperative cardiopulmonary function is therefore desirable to avoid (a) refusal of potentially curative treatment and (b) severe postoperative disability. The origins of post-resection morbidity and mortality are multifactorial. Thus, no single pulmonary function test or hemodynamic measurement can accurately and reliably predict postoperative cardiorespiratory complications. Criteria of functional operability should be based on percent of predicted value, so that patient's age, sex, and height will be taken into consideration. Exercise testing offers the advantage that both pulmonary and cardiac risk can be evaluated simultaneously. The high predictive value of maximal oxygen uptake (VO2max) in assessing postoperative morbidity and mortality is established. The calculation of predicted postoperative lung function (ppo) is of importance. The postoperative values for the forced expiratory volume in one second (FEV1-ppo), the transfer factor (TL,CO-ppo), and VO2max-ppo can be predicted by using the same formula. Patients with nearly normal lung function (FEV1, TL,CO > 75% predicted) and no concomitant cardiac disease can undergo lung resection right up to pneumonectomy without further diagnostic procedures. In the others, FEV1-ppo and TL,CO-ppo should be estimated first by taking into account the number of segments to be resected. Patients with values < 30% predicted are usually regarded as being inoperable, whereas values > 40% predicted qualify for resection without the need for further diagnostics. VO2max < 10 ml/kg/min or < 40% predicted are prohibitive for surgery. If VO2max is > 20 ml/kg/min or > 75% predicted, functional operability without limitation is given. For those cases where diagnostic uncertainty still remains, FEV1-ppo, TL,CO-ppo, and VO2max-ppo can be calculated by means of quantitative lung scans. Patients with either FEV1-ppo and TL,CO-ppo < 30% predicted or VO2max-ppo < 8 ml/kg/min or < 35% predicted are deemed inoperable.

Exercise Test↗
PubMed1999

[Correlation between epiluminescence microscopy characteristics of malignant melanomas and Clark's level of invasion].

Many epiluminescence microscopy (ELM) characteristics of malignant melanoma support the differential diagnosis of pigmented skin tumors. A preinvasive evaluation of level of invasion would be valuable for planning the excision margins. Since sonography for tumor thickness measurement is rarely available in a practice we searched for specific ELM criteria correlating with Clark's level of invasion. In our retrospective study of 120 malignant melanomas of 30 ELM features were studied for their correlation and the association was significant for 15 features.The following criteria were found only in level III-IV melanomas: intralesional horizontally elongated blood vessels, spontaneous microhemorrhages, plaster-of-Paris-like lacunae, grey-blue/yellowish-brown/reddish saccular pattern and eccentric nodes (reddish, livid, blue). 7 characteristics were predominantly found in level III-IV melanomas and seldom in "thin" melanomas (level I-II): deeply localized gray-blue/-brown fragmentary network, whitish-opaque septa, whitish- or bluish-opaque veil, negative pigmented network, areola with evenly arranged capillaries, polymorphic capillaries. Perivascular melanophages, eccentric dark blotches, pseudotrabeculae of melanophages and greyish-blue annular perifollicular pigmentations were the most significant association of ELM criteria in "thin" melanomas (level I-II). Epiluminescence microscopy is not only a tool for the differentiation of melanocytic lesions but also for a preinvasive evaluation of Clark's level of invasion.

Adult↗
PubMed1999

Reference values and human biological monitoring values for environmental toxins. Report on the work and recommendations of the Commission on Human Biological Monitoring of the German Federal Environmental Agency.

This article describes the working principles and working procedures of the Commission on Human Biological Monitoring, which was established in 1993 as a joint commission of the Federal Health Office (Bundesgesundheitsamt) and the Federal Environmental Agency (Umweltbundesamt) in Germany. One of the main tasks of the commission is to develop scientifically based criteria for the application of human biological monitoring and for the evaluation of human monitoring data in environmental medicine. In principle, two different kinds of criteria are recommended: (a) reference values and (b) human biological monitoring values (HBM values). Reference values are intended to indicate the upper margin of the current background exposure of the general population to a given environmental toxin at a given time. Reference values can be used to identify subjects with an increased level of exposure (in relation to background exposure) to a given environmental toxin. However, reference values do not represent health-related criteria for the evaluation of human biological monitoring data. HBM values are derived from human toxicology and epidemiology studies and are intended to be used as a basis for a health-related evaluation of human biological monitoring data. Usually the commission recommends two different HBM values: HBM I, the concentration of an environmental toxin in a human biological material (usually blood, serum, plasma, or urine) below which there is--according to the knowledge and judgement of the commission--no risk for adverse health effects in individuals of the general population: and HBM II, the concentration of an environmental toxin in a human biological material (usually blood, serum, plasma, or urine) above which there is--according to the knowledge and judgement of the commission and with regard to the environmental toxin under consideration--an increased risk for adverse health effects in susceptible individuals of the general population. The HBM I value can be considered a kind of alert value (from the toxicological point of view), whereas the HBM II value represents a kind of action level, at which attempts should be undertaken to reduce the level of exposure immediately and to carry out further medical examinations. Values between HBM I and HBM II should be considered a warning signal of the need to control the analytical measurement and to reduce the level of exposure of the concerned individual as reasonably as is achievable. At present, reference and HBM values are available for lead in blood, for cadmium and mercury in blood and urine, and for pentachlorophenol in plasma/serum and urine. Reference values have been established for some polychlorinated biphenyls in blood and plasma as well as for hexachlorocyclohexane and hexacholorobenzene in blood as well as for some organochlorine in human milk.

Adolescent↗
PubMed1999

Preoperative staging of esophageal carcinoma: miniprobe sonography versus conventional endoscopic ultrasound in a prospective histopathologically verified study.

BACKGROUND AND STUDY AIMS: Endosonographic staging of esophageal carcinoma may be limited by non-traversable tumor stenoses. Dilation of malignant esophageal strictures carries a significant risk of esophageal perforation. We therefore evaluated the use of ultrasonic miniprobes in the staging of stenotic esophageal carcinoma compared with conventional endoscopic ultrasound. PATIENTS AND METHODS: In a blinded, prospective study, which included histopathological evaluation, 53 consecutive patients (43 male, 10 female, mean age 61 years) with stenosing esophageal carcinomas were examined preoperatively. Endosonography was done using the optical GF-UM3 echo endoscope. If tumor strictures were not traversable with this instrument, a blind esophagoprobe, the MH-908 was used for endosonography. Miniprobe sonography (MPS) was done during esophagoscopy in all patients. The various imaging modalities were assessed in terms of complete tumor traversability and correct tumor staging. Every patient underwent surgical tumor resection. RESULTS: MPS of the esophagus and proximal parts of the stomach was possible in all 53 patients without prior dilation of tumor stenoses. Endosonography with the GF-UM3 instrument was precluded in 23 patients (43.4%) while in 20 of the latter patients the MH 908 esophagoprobe could be passed through tumor stenoses. The overall accuracy rates for depth of tumor infiltration (T) staging were: 62% (31/50) for endosonography (GF-UM3 plus esophagoprobe) and 86.8% (46/53) for MPS. The accuracy rates for T staging in tumors traversable both with the GF-UM3 echo endoscope and with miniprobes were 56.7% (17/30) for GF-UM3 and 80% (24/30) for MPS. The accuracy rates for T staging in tumors traversable only with the MH-908 esophagoprobe and with miniprobes were 70% (14/20) for the MH-908 and 95% (19/20) for MPS. With regard to the presence or absence of peri-esophageal metastatic lymph nodes (N staging), the accuracy rates were 83% (25/30) for MPS and 70% (21/30) for the GF-UM3, and 80% (16/20) for MPS and 70% (14/20) for the MH-908. CONCLUSION: Compared with conventional endosonography using 7.5-MHz large diameter instruments, MPS enables: a) safe passage through high-grade malignant esophageal strictures, achieving b) higher accuracy rates for T staging, and c) similar rates for N staging. The use of MPS can also represent an improvement in the comfort and safety of patients. Moreover, miniprobe sonography is highly cost-effective compared with conventional endosonography. Thus, MPS appears to be a valuable addition to the armamentarium for staging esophageal carcinoma.

Adult↗
PubMed1999

alpha-Thrombin stimulates contraction of human bronchial rings by activation of protease-activated receptors.

In a variety of diseases, inflammation causes microvascular leakage and activates thrombin. Evidence suggests that thrombin increases cytosolic calcium and stimulates human airway smooth muscle (ASM) cell proliferation. The receptor subtypes, however, that mediate the effects of thrombin on ASM cell growth or calcium mobilization remain unknown. In this study, we postulate that thrombin, which activates specific protease-activated receptors (PARs), also stimulates contraction of isolated human bronchial rings. With the use of intact human bronchial rings, alpha-thrombin (1-20 U/ml) increased bronchial tone to 19 +/- 3% of basal tone (P = 0.008; n = 5 experiments) and represents 20 +/- 8% of the maximum carbachol response. The EC(50) for thrombin-induced force generation was 12.2 U/ml (95% confidence interval 9.9-15.3 U/ml) and was not altered in bronchial rings that had the epithelium removed. In parallel experiments, a specific thrombin receptor-activating peptide (TRAP-14; 0.1-100 micromol/l) increased isometric tension to levels (14 +/- 2%; P = 0.0005; n = 5 experiments) comparable to those rings stimulated with thrombin. To characterize the receptors that mediate thrombin effects on human ASM, the expression of PARs in cultured human ASM cells was analyzed by RT-PCR analysis with specific primers for PARs. In these cells, PAR1 (thrombin receptor), PAR2, and PAR3 were expressed at comparable levels. In other experiments using immunocytochemical staining with specific antibodies to PAR1 and PAR2, we showed that ASM in bronchial rings and cultured ASM cells express PAR1 and PAR2 proteins. Taken together, these studies suggest that alpha-thrombin, in a receptor-specific and dose-dependent manner, induces contraction of bronchial rings in vitro. In addition, cultured human ASM cells express mRNA of PAR1, PAR2, and PAR3 and express PAR1 and PAR2 protein. Further studies are needed to determine whether alpha-thrombin plays a role in stimulating bronchoconstriction in inflammatory airway diseases such as asthma and bronchiolitis obliterans.

Adult↗
PubMed1999

[1998 environment survey--initial results].

In close connection with the German National Health Interview and Examination Survey 1998, a third round of the German Environmental Survey (GerES III) was carried out using a random subsample of about 4,500 subjects, which are representative for the German population aged 18 to 69 years. The GerES was carried out by the Federal Environmental Agency on behalf of the Federal Ministry for Environment, Nature Conservation and Reactor Safety. The participants had to undergo an examination in human-biomonitoring. An environmental questionnaire was used to get exposure-related information. Preliminary results indicate a reduction of the body burden with metals in 1998 compared with 1990/92. However, some individuals showed elevated values. For those people health effects are possible or cannot be excluded with sufficient certainty. Using the results of GerES III it will be possible for the first time to establish reference values for organochlorine compounds on a representative data basis. The examination of the tap water used in the subjects households shows that the limit and guideline values of the German Drinking Water Ordinance have not always been met in 1998. This holds especially for lead, copper, and zinc which are being used as pipe-material for domestic plumbing.

Adolescent↗
PubMed1998

The effect of lead in tap water on blood lead in children in a smelter town.

Hettstedt, a city in eastern Germany with a long history of mining and smelting of non-ferrous ores, has multiple lead waste deposits and the remains of a former lead smelter and a copper-silver smelter. As part of a cross-sectional study, an analysis of lead concentrations in drinking water and in blood was undertaken to determine the impact of lead in drinking water on the internal burden of lead in children. The geometric mean of blood lead levels among children 5-14 years old was 35.0 micrograms/l with a 95% confidence interval (C.I.) of 33.4-36.7. The geometric mean of lead in the random tap water samples was 0.5 microgram/l (95% C.I., 0.5-0.6) and 0.7 microgram/l (95% C.I., 0.6-0.8) in the stagnant tap water samples. Blood lead levels were somewhat correlated with the random water measures but not the stagnant water measures (random sample: r = 0.12, P = 0.012; stagnant sample: r = 0.04, P = 0.396). After adjustment for relevant confounders, lead in drinking water (random sample) was not significantly associated with blood lead levels. Factors that were significantly associated with blood lead included gender, the city area of residence, lead in house dust, regular contact with dogs and dirtiness of the child after playing outdoors. Based on this study, lead in domestic tap water contributed little to the lead exposure of children in the lead contaminated region of Hettstedt.

Adolescent↗