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Biomedical subjects

D Steiner

Publications and source records attributed to D Steiner.

At least 19 recordsLinked to original sources
PubMed2006

[Radiation synovectomy of the knee joint: Evaluation of bremsstrahlung-detection by using a corpse phantom].

AIM: Multiple procedures for the quantification of activity leakage in radiation synovectomy of the knee joint have been described in the literature. We compared these procedures considering the real conditions of dispersion and absorption using a corpse phantom. METHODS: We simulated different distributions of the activity in the knee joint and a different extra-articular spread into the inguinal lymph nodes. The activity was measured with a gamma-camera. Activity leakage was calculated by measuring the retention in the knee joint only using an anterior view, using the geometric mean of anterior and posterior views, or using the sum of anterior and posterior views. The same procedures were used to quantify the activity leakage by measuring the activity spread into the inguinal lymph nodes. In addition, the influence of scattered rays was evaluated. RESULTS: For several procedures we found an excellent association with the real activity leakage, shown by an r(2) between 0.97 and 0.98. When the real value of the leakage is needed, e. g. in dosimetric studies, simultaneously measuring of knee activity and activity in the inguinal lymph nodes in anterior and posterior views and calculation of the geometric mean with exclusion of the scatter rays was found to be the procedure of choice. CONCLUSION: When measuring of activity leakage is used for dosimetric calculations, the above-described procedure should be used. When the real value of the leakage is not necessary, e. g. for comparing different therapeutic modalities, several of the procedures can be considered as being equivalent.

Humans↗
PubMed2005

Electronic structure of metal-semiconductor nanojunctions in gold CdSe nanodumbbells.

The electronic properties of metal-semiconductor nanojunctions are investigated by scanning tunneling spectroscopy of gold-tipped CdSe rods. A gap similar to that in bare CdSe nanorods is observed near the nanodumbbell center, while subgap structure emerges near the metal-semiconductor nanocontact. This behavior is attributed to the formation of subgap interface states that vanish rapidly towards the center of the rod, consistent with theoretical predictions. These states lead also to modified Coulomb staircase, and in some cases to negative differential conductance, on the gold tips.

Journal Article↗
PubMed2005

Clara cell protein and surfactant protein B in garbage collectors and in wastewater workers exposed to bioaerosols.

OBJECTIVES: Inhalation of bioaerosols has been hypothesised to cause "toxic pneumonitis" that should increase lung epithelial permeability at the bronchioloalveolar level. Serum Clara cell protein (CC16) and serum surfactant protein B (SPB) have been proposed as sensitive markers of lung epithelial injury. This study was aimed at looking for increased lung epithelial permeability by determining CC16 and SPB in workers exposed to bioaerosols from wastewater or garbage. METHODS: Subjects (778 wastewater, garbage and control workers; participation 61%) underwent a medical examination, lung function tests [American Thoracic Society (ATS) criteria], and determination of CC16 and SPB. Symptoms of endotoxin exposure and several potential confounders (age, gender, smoking, kidney function, obesity) were looked for. Results were examined with multiple linear or logistic regression. RESULTS: Exposure to bioaerosols increased CC16 concentration in the wastewater workers. No effect of exposure on SPB was found. No clue to work-related respiratory diseases was found. CONCLUSIONS: The increase in CC16 in serum supports the hypothesis that bioaerosols cause subclinical "toxic pneumonitis", even at low exposure.

Adult↗
PubMed2004

A randomized double-blind placebo-controlled clinical trial of a product containing ephedrine, caffeine, and other ingredients from herbal sources for treatment of overweight and obesity in the absence of lifestyle treatment.

OBJECTIVE: To evaluate the efficacy and side effects of an herbal formulation to promote weight loss, as compared to placebo. DESIGN: 12-week multicenter double-blind, placebo-controlled, randomized parallel groups design. Study conducted at three clinical sites in New York State. Subjects were randomized to receive either the 'active' product or a 'placebo' supplement for 12 weeks. Minimal steps were taken to influence lifestyle changes with regard to diet or exercise. SUBJECTS: 102 overweight/obese (30<BMI</=39.9 kg/m(2)) volunteers between the ages of 18 and 65 y. MAIN OUTCOME MEASURES: Weight, percent body fat, fat mass, waist circumference, BMI, blood pressure, and pulse measured at 2 days, 1 week, 2 weeks, 4 weeks, 8 weeks, and 12 weeks postrandomization. RESULTS: Subjects receiving the 'active' treatment experienced, on average, an additional 1.5 kg of weight loss compared with subjects receiving the placebo. In addition, subjects receiving the 'active' treatment experienced greater reductions in BMI and waist circumference over the 12-week period. No differences were observed with respect to percent body fat, fat mass, diastolic or systolic blood pressure, pulse, the occurrence of any adverse event, or the occurrence of any presumed treatment-related adverse event. Testing of the study product by two independent laboratories indicated that it had only approximately half of the intended amount of ephedrine alkaloids and caffeine. CONCLUSIONS: Over the 12-week trial, subjects on the active treatment experienced significantly greater weight loss than subjects on placebo, without an increase in blood pressure, pulse, or the rate of adverse events. These benefits were achieved in the absence of any lifestyle treatment to change dietary or exercise behavior and with lower doses of ephedrine alkaloids and caffeine than those commonly utilized.

Adult↗
PubMed2004

Hepatitis E, Helicobacter pylori, and gastrointestinal symptoms in workers exposed to waste water.

BACKGROUND: Workers exposed to sewage may have an increased risk of infection by Helicobacter pylori and hepatitis E virus (HEV). AIMS: To assess the prevalence of clinical hepatitis E (HE) and peptic ulcer disease as well as the seroprevalence of antibodies to H pylori and HEV in workers with and without sewage exposure and to look for symptoms due to exposure to endotoxin. METHODS: In the first year of a prospective cohort study 349 sewage exposed workers and 429 municipal manual workers (participation: 61%) underwent a complete medical examination. Travelling to endemic areas, socioeconomic level, age, country in which childhood was spent, and number of siblings were considered as the main confounding factors. RESULTS: Peptic ulcer disease and clinical HE did not occur more often in workers exposed to sewage. Prevalence of antibodies to HEV was 3.3% and overall prevalence of IgG antibodies to H pylori was 42% with large differences between subgroups. Logistic regression did not show an increased risk of seropositivity or antibodies to parietal cells in sewage exposed workers, but disentangling the effect of exposure from that of confounders was extremely difficult. No increase of symptoms due to exposure to endotoxin was found in sewage workers, with the exception of diarrhoea. CONCLUSIONS: No clear increased risk of infection by H pylori or by HEV in workers exposed to sewage was found in this cross-sectional study, but these results need to be confirmed by follow up.

Adult↗
PubMed2003

[Hepatitis E and exposure to waste water].

Hepatitis E virus (HEV) is found in waste water which represents a route of infection. However, the risk for sewage workers is unknown. Thus, we aimed at determining the prevalence of anti-HEV antibodies in sewage workers from the Canton of Zurich. The anti-HEV antibodies evaluated in 288 subjects with exposure to sewage and 306 controls, a total of 594 subjects. Overall, twenty-two (3.7%) subjects had anti-HEV, the seroprevalence was similar in those exposed and controls. The most important risk factor, travelling in endemic areas, was lacking in two workers, who both were exposed to sewage. A follow up study in the population will soon give further evidence on the incidence rate.

Hepatitis Antibodies↗
PubMed2003

[Lung diseases in persons exposed to waste disposal dust].

The current cohort study in the canton of Zurich is investigating respiratory diseases in waste collectors. Therefore, a clinical history was taken and lung function tests and measurement of the Clara cell protein concentration were carried out. The first results show no elevation of the prevalence of asthma or other lung diseases in waste collectors. Compared with control subjects, waste collectors have a lower forced expiratory volume in the first second and a higher mean Clara cell protein concentration. The prevalence of cardiovascular risk factors such as smoking, obesity and arterial hypertension which are not caused by the occupation is high. Indeed, about 50% of all participants are hypertensive.

Adult↗
PubMed2003

Insulinoma presenting with hyperandrogenism: a case report and a literature review.

An 18-year-old woman presented with a 6-month history of amenorrhoea and hyperandrogenism. Three months later she developed several episodes of fasting hypoglycaemia and was subsequently diagnosed with an insulinoma. Hyperinsulinaemia was observed in association with an elevated serum testosterone level. Surgical removal of the insulinoma resulted in resolution of the clinical and biochemical features of the polycystic ovarian syndrome (PCOS). Polycystic ovarian syndrome is unusual in a patient having an insulinoma. The rarity of this association may be the result of the late age of onset of this type of tumour, intermittent secretion of excessive insulin by the tumour, the degree of hyperinsulinism or other factors extrinsic to the insulin receptor that may facilitate insulin activity. However, we could not discover how our patient differs in having had PCOS from the majority of women with insulinoma who do not. If other patients with insulinoma are subsequently found to have hyperandrogenism, then this tumour might be added to the differential diagnosis of causes of anovulatory cycles and hyperandrogenaemia, although rare the association would be uncommon.

Adolescent↗
PubMed2003

Abrogation of protein convertase 2 activity results in delayed islet cell differentiation and maturation, increased alpha-cell proliferation, and islet neogenesis.

To date, the role of pancreatic hormones in pancreatic islet growth and differentiation is poorly understood. To address this issue, we examined mice with a disruption in the gene encoding prohormone convertase 2 (PC2). These mice are unable to process proglucagon, prosomatostatin, and other neuroendocrine precursors into mature hormones. Initiation of insulin (IN) expression during development was delayed in PC2 mutant mice. Cells containing IN were first detected in knockout embryos on d 15 of development, 5 d later than in wild-type littermates. However, the IN(+) cells of d 15 PC2 mutant mice coexpressed glucagon, as did the first appearing beta-cells of controls. In addition, lack of PC2 perturbed the pattern of expression of transcription factors presumed to be involved in the determination of the mature alpha-cell phenotype. Thus, in contrast to controls, alpha-cells of mutant mice had protracted expression of Nkx 6.1 and Pdx-1, but did not express Brn-4. Islets of adult mutant mice also contained cells coexpressing insulin and somatostatin, an immature cell type found only in islets of the wild-type strain during development. In addition to the effects on islet cell differentiation, the absence of PC2 activity resulted in a 3-fold increase in the rate of proliferation of proglucagon cells during the perinatal period. This increase contributed to the development of alpha-cell hyperplasia during postnatal life. Furthermore, the total beta-cell volume was increased 2-fold in adult mutants compared with controls. This increase was due to islet neogenesis, as the number of islets per section was significantly higher in knockout mice compared with wild-type mice, whereas both strains had similar rates of IN cell proliferation. These results indicate that hormones processed by PC2 affected processes that regulate islet cell differentiation and maturation in embryos and adults.

Age Factors↗
PubMed2001

[Antigranulocyte scintigraphy of septic loosening of hip endoprosthesis: effect of different methods of analysis].

AIM: Diagnosis of infection with help of antigranulocyte scintigraphy near body stem is difficult because of contemporary visualisation of bone marrow. Therefore, we investigated, whether it is possible to improve the accuracy in diagnosing septic loosening of hip endoprosthesis by changing the analyzing methods. METHODS: In 28 patients, the results of a visual interpretation of late scan, a visual interpretation and a quantitative interpretation of time-activity-course were compared. These results were verified by histology respectively microbiology. RESULTS: Histological and microbiological verification found 14 septic loosening and 14 aseptic loosening of the hip prothesis. Therefore, sensitivity, specificity, negative and positive predictive value for the visual interpretation of late scan were 0.86, 0.57, 0.80 and 0.67. For visual and quantitative interpretation of time-activity-course we found 0.86, 0.79, 0.85 and 0.80 respectively 1, 0.93, 1, 0.93. For interobserver agreement we found kappa coefficients of 0.28 +/- 0.2 for visual interpretation of late scan, 0.48 +/- 0.17 for visual interpretation and 1.0 +/- 0 for quantitative interpretation of time-activity-course. CONCLUSION: In all investigated values quantitative interpretation of time-activity-course was superior to the other analyzing methods. Therefore, antigranulocyte scintigraphy for septic loosening of hip endoprosthesis should be interpreted quantitatively.

Antibodies, Monoclonal↗
PubMed2000

Current practice of radioiodine treatment in the management of differentiated thyroid cancer in Germany.

This prospective, observational study of a cohort of thyroid cancer patients in Germany focusses on the "real-world" practice in the management of thyroid cancer patients. This report includes data from 2376 patients with primary differentiated thyroid carcinoma first diagnosed in the year 1996. The study reveals considerable differences in actual practice concerning surgery and radioiodine treatment. The results indicate that consensus is lacking with respect to the multimodality treatment approach for differentiated thyroid carcinoma. Our analysis represents the most current and comprehensive national assessment of presenting patient characteristics, diagnostic tests, treatment and complications for thyroid cancer.

Adenocarcinoma, Follicular↗
PubMed2000

A scaffoldin of the Bacteroides cellulosolvens cellulosome that contains 11 type II cohesins.

A cellulosomal scaffoldin gene, termed cipBc, was identified and sequenced from the mesophilic cellulolytic anaerobe Bacteroides cellulosolvens. The gene encodes a 2,292-residue polypeptide (excluding the signal sequence) with a calculated molecular weight of 242,437. CipBc contains an N-terminal signal peptide, 11 type II cohesin domains, an internal family III cellulose-binding domain (CBD), and a C-terminal dockerin domain. Its CBD belongs to family IIIb, like that of CipV from Acetivibrio cellulolyticus but unlike the family IIIa CBDs of other clostridial scaffoldins. In contrast to all other scaffoldins thus far described, CipBc lacks a hydrophilic domain or domain X of unknown function. The singularity of CipBc, however, lies in its numerous type II cohesin domains, all of which are very similar in sequence. One of the latter cohesin domains was expressed, and the expressed protein interacted selectively with cellulosomal enzymes, one of which was identified as a family 48 glycosyl hydrolase on the basis of partial sequence alignment. By definition, the dockerins, carried by the cellulosomal enzymes of this species, would be considered to be type II. This is the first example of authentic type II cohesins that are confirmed components of a cellulosomal scaffoldin subunit rather than a cell surface anchoring component. The results attest to the emerging diversity of cellulosomes and their component sequences in nature.

Amino Acid Sequence↗
PubMed2000

Comparison of HIG scintigraphy and bloodpool scintigraphy using HDP in arthritic joint disease.

AIM: Because of a similar tracer accumulation, we assumed to get the same information about synovitis in arthritic joint disease with HIG scintigraphy and bloodpool scintigraphy using HDP. Therefore, we compared retrospectively 23 patients. METHODS: In HIG scintigraphy, synovitis was diagnosed according to increasing activity from early to late image. In bloodpool scintigraphy according to an increased activity in comparison to the surrounding tissues. RESULTS: In 694 joints comparison of both scintigraphic modalities was possible, resulting in a 2 x 2 kappa coefficient of 0.93 or 0.97 by using late-phase bone scintigraphy as an anatomical marker. For intra- and interobserver agreement, 2 x 2 kappa coefficients of 0.93 and 0.88 in HIG scintigraphy, respectively 0.96 and 0.90 in blood-pool scintigraphy were calculated. CONCLUSION: This study shows an excellent agreement in the visualization of synovitis by HIG and bloodpool scintigraphy. Because of its higher objectivity and lower cost, investigation of synovitis should be performed by bloodpool scintigraphy.

Adult↗
PubMed1999

The value of renal scintigraphy during controlled diuresis in children with hydronephrosis.

Dynamic renal scintigraphy (DRS) during controlled diuresis is the method of choice to diagnose the functional relevance of urinary tract obstruction in children with sonographically demonstrated hydronephrosis. However, there are no commonly accepted scintigraphic criteria for surgical intervention. On the basis of our findings, we propose four stages of washout (WO) of tracer following diuresis: in stage I, WO>50%, neither further diagnosis nor intervention is necessary; in stage II, 50%>/=WO>/=12%, repetition of DRS is advised within 3-4 months; and in stage III, 12%>WO>/=5%, DRS should be repeated within 1-2 months. Only in stage IV, WO<5%, should surgery be done immediately. This procedure reduces surgical interventions by 50% without increasing the risk of residual renal damage.

Diuresis↗
PubMed1999

[Activity leakage and radiation exposure in radiation synovectomy of the knee: influence of different therapeutic modalities].

In rheumatic diseases, radiation synovectomy is a reliable method. Meanwhile, radiation synovectomy is an outpatient therapy. In addition, combination with arthroscopic synovectomy is an increasing therapeutic modality. In comparison to the hitherto inpatient modality, a greater lymphatic emigration of the radionuclide and, therefore, a higher radiation exposure is possible. In 35 patients we found radionuclide emigration in 17 cases by whole body scintigraphy, resulting in a 50%-percentile with 68.27%-confidence interval of 1.8 (0.45-4.78)% of the injected yttrium-90-activity. Comparison of 3 groups with the above mentioned therapy modalities resulted in no statistical difference (p>0.05). Because of the found radionuclide emigration, a radiation dose of 0. 1 (0.05-0,18) mSv in women and 0.2 (0.1-0.38) mSv in men was calculated. For lymph nodes, liver, spleen and whole body radiation doses of 619 (154-1644) mSv, 62 (15-165) mSv, 62 (15-165) mSv and 37 (9-99) mSv were calculated. Gonadal radiation dose can be neglected and the morbidity rate for tumors because of the whole body radiation dose is low with a value of 0.4 per thousand. Therefore, radiation synovectomy can be used unlimited by patients age and independent of the therapeutic modality.

Adult↗
PubMed1999

A novel cellulosomal scaffoldin from Acetivibrio cellulolyticus that contains a family 9 glycosyl hydrolase.

A novel cellulosomal scaffoldin gene, termed cipV, was identified and sequenced from the mesophilic cellulolytic anaerobe Acetivibrio cellulolyticus. Initial identification of the protein was based on a combination of properties, including its high molecular weight, cellulose-binding activity, glycoprotein nature, and immuno-cross-reactivity with the cellulosomal scaffoldin of Clostridium thermocellum. The cipV gene is 5,748 bp in length and encodes a 1,915-residue polypeptide with a calculated molecular weight of 199,496. CipV contains an N-terminal signal peptide, seven type I cohesin domains, an internal family III cellulose-binding domain (CBD), and an X2 module of unknown function in tandem with a type II dockerin domain at the C terminus. Surprisingly, CipV also possesses at its N terminus a catalytic module that belongs to the family 9 glycosyl hydrolases. Sequence analysis indicated the following. (i) The repeating cohesin domains are very similar to each other, ranging between 70 and 90% identity, and they also have about 30 to 40% homology with each of the other known type I scaffoldin cohesins. (ii) The internal CBD belongs to family III but differs from other known scaffoldin CBDs by the omission of a 9-residue stretch that constitutes a characteristic loop previously associated with the scaffoldins. (iii) The C-terminal type II dockerin domain is only the second such domain to have been discovered; its predicted "recognition codes" differ from those proposed for the other known dockerins. The putative calcium-binding loop includes an unusual insert, lacking in all the known type I and type II dockerins. (iv) The X2 module has about 60% sequence homology with that of C. thermocellum and appears at the same position in the scaffoldin. (v) Unlike the other known family 9 catalytic modules of bacterial origin, the CipV catalytic module is not accompanied by a flanking helper module, e.g., an adjacent family IIIc CBD or an immunoglobulin-like domain. Comparative sequence analysis of the CipV functional modules with those of the previously sequenced scaffoldins provides new insight into the structural arrangement and phylogeny of this intriguing family of microbial proteins. The modular organization of CipV is reminiscent of that of the CipA scaffoldin from C. thermocellum as opposed to the known scaffoldins from the mesophilic clostridia. The phylogenetic relationship of the different functional modules appears to indicate that the evolution of the scaffoldins reflects a collection of independent events and mechanisms whereby individual modules and other constituents are incorporated into the scaffoldin gene from different microbial sources.

Amino Acid Sequence↗
PubMed1998

The role of assembly in insulin's biosynthesis.

Insulin is synthesised as a single-chain precursor, preproinsulin, that contains an N-terminal signal sequence and a connecting peptide linking the A and B chains of the insulin molecule. Nascent proinsulin is directed into the regulated secretory pathway, converted to insulin and stored as microcrystals. These processes exploit assembly to the zinc-containing hexamer. Structural, chemical and genetic studies, and experiments with transgenic animals and transfected cells are providing new details about the molecular events in insulin's biosynthesis.

Animals↗