Search PubMed⌕ Search

Biomedical subjects

T Schmid

Publications and source records attributed to T Schmid.

At least 19 recordsLinked to original sources
PubMed2006

Expression of superficial zone protein in mandibular condyle cartilage.

OBJECTIVE: Superficial zone protein (SZP) has been shown to function in the boundary lubrication of articular cartilages of the extremities. However, the expression of SZP has not been clarified in mandibular cartilage which is a tissue that includes a thick fibrous layer on the surface. This study was conducted to clarify the distribution of SZP on the mandibular condyle and the regulatory effects of humoral factors on the expression in both explants and fibroblasts derived from mandibular condyle. METHODS: The distribution of SZP was determined in bovine mandibular condyle cartilage, and the effects of interleukin-1beta (IL-1beta) and transforming growth factor-beta (TGF-beta) on SZP expression were examined in condyle explants and fibroblasts derived from the fibrous zone of condyle cartilage. RESULTS: SZP was highly distributed in the superficial zone of intact condyle cartilage. The SZP expression was up-regulated by TGF-beta in both explants and cultured fibroblasts, whereas the expression was slightly down-regulated by IL-1beta. A significant increase in accumulation of SZP protein was also observed in the culture medium of the fibroblasts treated with TGF-beta. CONCLUSIONS: These results suggest that SZP plays an important role in boundary lubrication of mandible condylar cartilage, is synthesized locally within the condyle itself, and exhibits differential regulation by cell mediators relevant to mandibular condyle repairing and pathologies.

Animals↗
PubMed2006

High predictive value of epidermal growth factor receptor phosphorylation but not of EGFRvIII mutation in resected stage I non-small cell lung cancer (NSCLC).

AIMS: Overexpression and mutation of epidermal growth factor regulator (EGFR) are frequently found in the carcinogenesis of non-small cell lung cancer (NSCLC). Because targeting of this receptor has proven therapeutic efficacy, studying EGFR has become a matter of particular scientific interest. The present study analysed the EGFR receptor, rate of EGFRvIII mutations, and rate of activated phosphorylated EGFR (pEGFR) by immunohistochemistry on cryostat sections. METHODS: Surgically obtained tumour specimens of a series of 78 NSCLC patients and 66 adjacent tumour free specimens were examined immunohistochemically using monoclonal antibodies to stain EGFR, pEGFR, and EGFRvIII. RESULTS: EGFRvIII and pEGFR expression was found in 42% and 26% of the tumours respectively and both were increased significantly compared with tumour free samples. EGFR, pEGFR, and EGFRvIII expression did not correlate with any of the previously tested markers (c-erbB-2, c-erbB-3, p53, ki-67, and microvessel density). Similar distributions of immunohistochemical profiles were seen, regardless of histological subtype, age, or sex. In stage I patients, EGFR phosphorylation at tyrosine residue 845 proved to be an independent prognostic factor. CONCLUSION: Because pEGFR correlated with poor prognosis, it can be speculated that it plays a crucial biological role in the pathogenesis of NSCLC.

Biomarkers, Tumor↗
PubMed2005

Mercury content in vegetation and soils of the Almadén mining area (Spain).

The Almadén area is an exceptional case of mercury concentration in the world, where cinnabar is the predominant mineralised form. Mining activities have been carried out over the past two thousand years and once this activity is concluded, a restoration of the environment is necessary for the affected areas. That implies the selection, optimisation and application of the most appropriate techniques focused on the recovery of contaminated areas. Phytotechnology is one of the proposed techniques, which considers the use of plants due to the low environmental impact and their proved efficiency. In this framework, it is necessary to study the behaviour of mercury in the soil-plant system and to determine the mercury absorption capacity of the different Almadén plant species. Therefore, field and laboratory studies have been carried out to determine the easily available forms of mercury in ten test plots in the Almadén area and the resulting data is related to the mercury accumulation in different plant species of the studied territory. Special attention is given to the easily available forms of mercury in the analysed soils and used as the transfer factor for the Hg-availability index that relates the amount of mercury in a plant with the total amount of mercury in a soil and with the easily available forms. The result of this experimental work is selecting the plant species suitable to be used in a future implementation of phytotechnologies in this area.

Environmental Monitoring↗
PubMed2005

Mercury and trace element fractionation in Almaden soils by application of different sequential extraction procedures.

A comparative evaluation of the mercury distribution in a soil sample from Almaden (Spain) has been performed by applying three different sequential extraction procedures, namely, modified BCR (three steps in sequence), Di Giulio-Ryan (four steps in sequence), and a specific SEP developed at CIEMAT (six steps in sequence). There were important differences in the mercury extraction results obtained by the three procedures according to the reagents applied and the sequence of their application. These findings highlight the difficulty of setting a universal SEP to obtain information on metal fractions of different mobility for any soil sample, as well as the requirement for knowledge about the mineralogical and chemical characteristics of the samples. The specific six-step CIEMAT sequential extraction procedure was applied to a soil profile (Ap, Ah, Bt1, and Bt2 horizons). The distribution of mercury and major, minor, and trace elements in the different fractions were determined. The results indicate that mercury is mainly released with 6 M HCl. The strong association of mercury with crystalline iron oxyhydroxides, present in all the horizons of the profile, and/or the solubility of some mercury compounds in such acid can explain this fact. Minor mercury is found in the fraction assigned to oxidizable matter and in the final insoluble residue (cinnabar).

Journal Article↗
PubMed2004

Robot-assisted mediastinal parathyroidectomy.

We report the first case of robot-assisted thoracoscopic resection of a mediastinal parathyroid adenoma in the aorto-pulmonary window. Intervention planning was based on preoperative CT-MIBI image fusion, a new imaging modality that enabled reliable and precise localization of the parathyroid. The technique consists of taking MIBI-SPECT and CT separately, using a fixation unit that provides reproducible positioning of the patients head and neck. The data sets are then superimposed upon each other using special software. After the localization process, a minimally invasive operation was performed using the DaVinci operating robot. The procedure proved not only to be feasible but also safe and not time-consuming. The postoperative course was uneventful, and the patient was discharged 4 days postoperatively. Compared to conventional thoracoscopic surgery, the robotic operating system provides better visualization of the operating field and facilitates the movement of the instruments. Precise preoperative imaging enables the careful planning of robot-assisted surgery for ectopic parathyroids located at relatively inaccessible regions such as the anterior mediastinum.

Adenoma↗
PubMed2004

First experiences with the da Vinci operating robot in thoracic surgery.

OBJECTIVES: The da Vinci surgical robotic system was purchased at our institution in June 2001. The aim of this trial was to evaluate the applicability of the da Vinci operation robot for general thoracic procedures. METHODS: The da Vinci surgical system consists of a console connected to a surgical arm cart, a manipulator unit with two instrument arms and a central arm to guide the endoscope. The surgical instruments are introduced via special ports and attached to the arms of the robot. The surgeon, sitting at the console, triggers highly sensitive motion sensors that transfer the surgeon's movements to the tip of the instruments. The so-called 'EndoWrist technology' offers seven degrees of movement, thus exceeding the capacity of a surgeon's hand in open surgery. We evaluated the role of the robot for several thoracic procedures such as thymectomies, fundoplications, esophageal dissections, resection of mediastinal masses and a pulmonary lobectomy. RESULTS: A total of 10 thymectomies, 16 fundoplications, 4 esophageal dissections, 5 extirpations of benign mediastinal masses and 1 right lower lobectomy was performed with the robot. One resection of a paravertebral neurogenic tumor had to be converted due to surgical problems. A lesion to a left recurrent laryngeal nerve caused transient hoarseness after the extirpation of an ectopic parathyroid in the aortopulmonary window in one patient. The postoperative courses were uneventful and patients were discharged between postoperative days 3 and 8 (with the exception of patients who underwent dissection for esophageal cancer and the patient with conversion to an open access). CONCLUSIONS: Advanced general thoracic procedures can be performed safely with the da Vinci robot allowing precise dissection in remote and difficult-to-reach areas. This benefit becomes evident most elegantly in thymectomies, which at our institution have become a routine procedure with the robot. The rigid anatomy of the chest seems to be an ideal condition for robotic surgery. A major limitation for robotic surgery is the lack of more appropriate instruments. This disadvantage becomes most evident in pulmonary lobectomies.

Adult↗
PubMed2004

Investigation of biocide efficacy by photoacoustic biofilm monitoring.

The undesired growth of biofilms on solid surfaces is often termed biofouling. Biofilms consist mainly of water and microbial cells which are embedded in a biopolymer matrix. Biofouling lowers the water quality and increases the frictional resistance in tubes. Further, biofilms increase the pressure differences in membrane processes and can clog filtration membranes, valves, and nozzles. For investigation and improvement of biocide efficacy and anti-fouling strategies, on-line and in situ monitoring of the biofilm is necessary. In this study, photoacoustic spectroscopy (PAS) was employed for biofilm monitoring. PAS allows the depth-resolved investigation of growth and detachment processes of biofilms. Strategies based on the oxidant hydrogen peroxide were compared to popular isothiazolinone biocides. Hydrogen peroxide allowed a very fast and efficient removal of attached biofilms, whereas no effect on the biofilm matrix was observed in most cases when isothiazolinone biocides were used.

Acoustics↗
PubMed2004

CD133 positive endothelial progenitor cells contribute to the tumour vasculature in non-small cell lung cancer.

AIMS: Recent results generated in a mouse model suggest that tumour angiogenesis/vasculogenesis can be initiated and maintained by bone marrow derived endothelial progenitor cells. This present study investigated the distribution and frequency of CD133 positive endothelial progenitor cells in patients with non-small cell lung cancer (NSCLC) (tumour tissue and tumour free lung regions) and healthy controls using fresh frozen specimens. The novel marker CD133 identifies human haemopoetic precursor cells, in addition to human endothelial progenitor cells. METHODS: Seventy nine lung cancer specimens and 66 adjacent histologically tumour free tissues of the same patient cohort were analysed; 11 postmortem specimens from control patients who did not suffer from malignant disease served as controls. Cryostat sections were stained for CD133, CD31, vascular endothelial growth factor receptor 2 (VEGFR-2; KDR), p53, and the proliferation marker Ki-67, and the correlations were analysed. RESULTS: Forty three of 63 evaluable tumour specimens had increased numbers of CD133 positive cells and in some cases capillary forming CD133 positive structures were detectable. In addition, 30 of 63 specimens had raised expression of KDR and 29 of 63 had increased MVD. Increased CD133 expression marginally correlated with raised KDR expression but not with p53 and Ki-67. CONCLUSION: A significant increase in CD133 positive cells was documented in patients with NSCLC, suggesting an involvement of endothelial progenitor cells in tumour vasculogenesis and tumour growth in these patients.

AC133 Antigen↗
PubMed2004

Do contrast agents affect ultrasound flow measurements?

The use of iodine contrast agents during angiography can put patients at risk. The replacement of angiography through duplex ultrasound methods would, therefore, be of great interest. Even when duplex sonography is used however, an x-ray angiography is often performed afterwards to verify the diagnosis. This causes complications in an unacceptable number of patients. The safety of duplex ultrasound sonography diagnosis can be improved by using low-risk Doppler contrast agents. Slow blood flow through vessels with a high degree stenosis and intracerebral flow can be more easily and accurately detected using these agents. However, amplification of the Doppler echo alters the measurements during both high and low flow, so that the flow rate cannot be recorded very precisely. Our goal was to study the effect of a contrast agent on velocity measurements with color-coded Doppler ultrasonography and on pulsed, one-goal measurements. We used a laser-Doppler-anemometer (LDA) with high temporal and spatial resolution as a reference method to compare the measurements.

Blood Flow Velocity↗
PubMed2003

On-line monitoring of opaque liquids by photoacoustic spectroscopy.

A new photoacoustic sensor system for on-line monitoring of highly concentrated and optical opaque liquid samples is presented. The dyeing of textiles is performed with highly concentrated dye solutions with concentrations ranging from 50 mg L(-1) up to 40 g L(-1). For process optimization and control of the wastewater, an on-line monitoring of the dye concentration is needed. Optical transmission measurements allow the determination of the dye concentration in a relatively small range. Samples with concentrations in the upper mg L(-1) and g L(-1) range have to be diluted before the measurement due to their optical opacity. Additionally, light-scattering particles have a strong effect on the transmitted light intensity. By photoacoustic spectroscopy, concentrations in condensed matter can be determined over several orders of magnitude. Furthermore, scattering particles do not generate any photoacoustic signal.

Journal Article↗
PubMed2003

Robot-assisted laparoscopic partial posterior fundoplication with the DaVinci system: initial experiences and technical aspects.

BACKGROUND: This pilot study evaluated the role of the DaVinci operation robot for laparoscopic antireflux surgery. PATIENTS AND METHODS: A robot-assisted laparoscopic Toupet-fundoplication was performed on nine consecutive patients with severe gastroesophageal reflux disease using the DaVinci robot system. The operative procedure was performed in the same way as for the conventional laparoscopic procedure. Clinical assessment and endoscopic and manometric follow-up investigations were performed 6 months after surgery in six of the patients. RESULTS: The mean robotic operative time was 173 min (120-235). A mean of 25 min (12-45) was required to establish the pneumoperitoneum, to set the trocars, and to place the robot arms. There were no intraoperative complications. Six months after surgery none of the patients suffered from reflux symptoms and none of the patients had acute esophagitis. Postoperatively one patient complained of mild transient dysphagia. However, persistent dysphagia was not found in any of the patients. One further patient complained of mild bloating. No other side effects occurred. Manometrically there was a significant improvement in the function of the lower esophageal sphincter. CONCLUSIONS: The robot-assisted partial posterior fundoplication is a safe procedure and provides a high-quality three-dimensional camera image that is superior to that with the conventional laparoscopic device. The handling of the instruments is precise, and intracorporeal suturing and knot tying is much easier than without the robotic technique. The procedure allows for an accurate approximation of the hiatal crura and for precise construction of the fundic wrap. However, robotic surgery is expensive and the setup of the system is time consuming at present.

Adult↗
PubMed2003

Process analysis of biofilms by photoacoustic spectroscopy.

Biofilms are aggregates of microorganisms and biopolymers which occur at aqueous interfaces. Biofilms play an important role in the degradation of pollutants in natural water systems as well as in wastewater treatment plants. In this communication, the use of photoacoustic spectroscopy (PAS) as a new biofilm monitoring technique is presented. PAS combines features of optical spectroscopy and ultrasonic tomography and allows a depth-resolved analysis of optically and acoustically inhomogeneous media. For the first time, both biofilm and bulk liquid were monitored by photoacoustic sensor heads. In this way, sorption of suspended iron(III) oxide particles on the outer and inner surfaces of the biofilm could be observed on-line and in situ. Colloids can act as carriers of pollutants and influence stability and degradation efficiency of biofilms.

Acoustics↗
PubMed2003

An evaluation of a community-based approach to safe motherhood in northwestern Tanzania.

OBJECTIVES: We present an evaluation of the Community Capacity Building and Empowerment initiative, undertaken by the Community-Based Reproductive Health Project (CBRHP), designed to address high maternal morbidity and mortality. METHODS: Qualitative data from group interviews and program data from CBRHP were used to assess progress in development and use of community level transport systems and support for the village health workers (VHWs). RESULTS: Project activities increased community participation in maternal health. An increase was seen in knowledge of danger signs, birth planning, timely referrals, and transport of pregnant women to hospitals, as well as in support and retention of VHWs. More women with obstetrical problems are using the community-based transport system to get to hospitals. CONCLUSIONS: Community participation and support for VHW activities and the transport systems have led to better care for pregnant women and sustained links between the communities and health facilities, which may reduce maternal and infant morbidity and mortality.

Attitude to Health↗
PubMed2003

Recombinant osteogenic protein-1 upregulates extracellular matrix metabolism by rabbit annulus fibrosus and nucleus pulposus cells cultured in alginate beads.

This study was performed to determine if recombinant human osteogenic protein-1 (rhOP-1) is effective in promoting matrix synthesis and matrix formation by rabbit nucleus pulposus (NP) and annulus fibrosus (AF) cells cultured in alginate beads. The effects of culturing the cells in the presence of various concentrations of rhOP-1 were assessed by measuring changes in cell proliferation, proteoglycan (PG) and collagen synthesis and mRNA expression, and in the matrix contents of PG and collagen, as indicators of matrix accumulation. At high concentrations, rhOP-1 had a moderate mitogenic effect on both NP and AF cells. It also stimulated the synthesis of PG and collagen in a dose-dependent manner: this was associated with a corresponding increase in the expression of mRNA for aggrecan core protein and collagen type II. The stimulatory effect of rhOP-1 on PG synthesis was more pronounced than that on collagen synthesis. Continuous treatment with rhOP-1 led to an increase in the total DNA, PG and collagen contents in both NP and AF cultures. The results presented here provide evidence of the ability of rhOP-1 to stimulate the metabolism of both rabbit AF and NP cells cultured in alginate beads.

Aggrecans↗
PubMed2003

Immunohistochemical typing of non-small cell lung cancer on cryostat sections: correlation with clinical parameters and prognosis.

AIMS: To investigate the immunohistochemical expression of a panel of biologically relevant markers in patients with non-small cell lung cancer using fresh frozen specimens and to test their prognostic relevance for identification of patients at risk. METHODS: Seventy nine tumour infiltrated lung cancer specimens and 66 adjacent histologically tumour free tissues were analysed; 11 postmortem specimens from patients who did not suffer from a malignant disease served as a control group. Cryostat sections were stained with monoclonal antibodies against epidermal growth factor receptor (EGFR), c-erbB-2, c-erbB-3, CD82, Ki-67, p120, p53, bcl-2, and CD31. RESULTS: At least one of the tested markers was raised above the defined cut off point in 75 of the tumours. In 55, three to six factors were increased. EGFR was raised in 32, c-erbB-2 in 29, c-erbB-3 in 46, p53 in 29, bcl-2 in 26, Ki-67 in 36, p120 in 46, and CD31 in 29. None of the tested parameters was significant in univariate survival analysis. In a second step, three variables were combined (c-erbB3, p53, and microvessel density), and cases with increased expression of two or three parameters proved to have a significantly lower survival probability than those expressing none or only one factor. In the tumour free group only 10 showed raised marker expression. CONCLUSION: Characterisation of tumour cells in surgical specimens with immunohistological markers could help identify those patients at risk for early cancer death who could possibly profit from adjuvant treatment after curative tumour resection.

Antigens, CD↗