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C Lang

Publications and source records attributed to C Lang.

At least 19 recordsLinked to original sources
PubMed2006

Real time observation of GeSi/Si(001) island shrinkage due to surface alloying during Si capping.

The Si capping of Ge/Si(001) islands was observed by in situ time-resolved transmission electron microscopy. During the initial stages of the Si deposition, islands were observed not only to flatten but also to shrink in volume. This unexpected shrinkage is explained by taking into account the intermixing of the deposited Si with the wetting layer and a consequently induced diffusion of Ge from the islands into the wetting layer. A model of the capping process which takes into account Ge diffusion is presented which is in good agreement with the experimental data.

Journal Article↗
PubMed2006

Eukaryotic expression: developments for structural proteomics.

The production of sufficient quantities of protein is an essential prelude to a structure determination, but for many viral and human proteins this cannot be achieved using prokaryotic expression systems. Groups in the Structural Proteomics In Europe (SPINE) consortium have developed and implemented high-throughput (HTP) methodologies for cloning, expression screening and protein production in eukaryotic systems. Studies focused on three systems: yeast (Pichia pastoris and Saccharomyces cerevisiae), baculovirus-infected insect cells and transient expression in mammalian cells. Suitable vectors for HTP cloning are described and results from their use in expression screening and protein-production pipelines are reported. Strategies for co-expression, selenomethionine labelling (in all three eukaryotic systems) and control of glycosylation (for secreted proteins in mammalian cells) are assessed.

Animals↗
PubMed2006

Changes of the cortex proteome and Apolipoprotein E in transgenic mouse models of Alzheimer's Disease.

Transgenic mice carrying human Amyloid Precursor Protein mutations present amyloid plaque deposition in the brain upon aging. In this study, we characterized the changes of cortex proteome and endogenous Apolipoprotein E in these mice. Differential analysis of two-dimensional electrophoresis images revealed spots altered upon aging, transgene addition and plaque deposition. Alpha-synuclein and cytochrome oxidase polypeptide Va were up-regulated in transgenic mice. Upon aging, expression of ATP synthase alpha, alpha enolase, UMP-CMP kinase, and dihydropyrimidinase like-2 protein was modified. These proteins and their modification probably play a role in the amyloid aggregate formation in these mice.

Alzheimer Disease↗
PubMed2006

Comparative efficiency of the multi-leaf collimator and variable-aperture collimator in intensity-modulated radiotherapy.

The potential of the variable-aperture collimator (VAC) in intensity-modulated radiation therapy (IMRT) has been evaluated by comparing its performance with that of the multi-leaf collimator (MLC). This comparison used a decomposition algorithm to find the series of collimator segments that would treat a given intensity-modulated beam (IMB). Collimator performance was measured using both the number of segments required to complete the IMB and the monitor-unit efficiency of the treatment. The VAC was modelled with aperture sizes from 4 x 4 cm to 20 x 20 cm, and these apertures were allowed to be located anywhere within the IMB. To enable a direct comparison, a similar scanning MLC was modelled at the same range of aperture sizes. Using both collimators, decompositions were run on 10 x 10 and 20 x 20 random IMBs with integer bixel values ranging from 1 to 10. Clinical IMBs from lung, head and neck, and pelvic patients were taken from a Pinnacle treatment-planning system and tested in the same manner. It was found that for all treatment sites, a small, scanning MLC performs as well or better than an equivalent sized VAC in both number of segments and monitor-unit efficiency, and would be an efficient choice for centres looking for a simple collimator for IMRT.

Algorithms↗
PubMed2006

First findings concerning airflow in noses with septal deviation and compensatory turbinate hypertrophy--a model study.

BACKGROUND: The nasal septal deviation is a common cause of nasal obstruction. On the other hand, many septal deviations are asymptomatic. It seems a physiological adaptation occurs on both sides. Septal deviation leads to internal nasal asymmetry, which in turn causes compensatory change in turbinate morphology (e.g. turbinate hypertrophy respectively hypotrophy). This mechanism is investigated with the help of fluid dynamic experiments and functional rhinologic diagnostics. METHODS: Functional models of the nose (modified Mink's boxes) were used and assessment was made by acoustic rhinometry and rhinoresistometry, followed by flow dynamic investigations. Septal deviations of varying position, together with turbinates of differing grades of hypertrophy, were simulated and assessed. RESULTS AND CONCLUSIONS: We observed in models of septal deviation an increase in flow resistance on the ipsilateral side as a result of friction of flow particles in the narrowing. Furthermore, on the opposite side of the deviation, the enlargement of the stream channel did not generally lead to a reduction in flow resistance, but rather to a 'dead space', where only a slow-circling eddy was observed. This eddy causes an increase in turbulence. In vivo turbinate hypertrophy occurs to fill this dead space, thereby reducing turbulent flow without a significant increase in resistance. In cases of moderate septal deviation, compensatory mechanisms of the turbinates can lead to a normalization of nasal airflow and surgical therapy would not be indicated. Deviations in the anterior part of the septum seem to be more symptomatic, because the mechanism is missing and due to the physiological narrowing of the nasal isthmus. To differ between physiologic and pathologic deviation, functional diagnostics are needed.

Computer Simulation↗
PubMed2006

Botulism in a pregnant intravenous drug abuser.

A case of botulism is reported in a heroin-abusing parturient who initially presented with lethargy and slurred speech. The diagnostic difficulty, complications, intensive care and anaesthetic management of this case are discussed, with particular reference to the pregnancy and the effects of both botulism and its empirical treatment on the fetus. A short review is provided of a condition that has seen a marked increase in its incidence since 2000.

Adult↗
PubMed2005

Hepatic carbohydrate metabolism in rats after laparotomy and laparoscopy.

BACKGROUND: Portal venous and mesenteric blood flow are reduced by 40-60% in humans and animals during laparoscopic surgery compared to laparotomy. Little is known about whether these intraabdominal micro- and macrocirculatory changes are associated with alterations in the hepatic energy metabolism. METHODS: We operated on male Sprague-Dawley rats, performing either laparoscopy (CO2, 6 mmHg; n = 27) or laparotomy (n = 28), and compared the results with two control groups: intraperitoneal (i.p.) endotoxin administration (n = 28, positive control) and anesthesia only (n = 28, negative control). We investigated the impact of the two different surgical techniques on daily food intake, body weight gain, glycogen content in the liver, levels of blood glucose, and liver function tests (LFTs) on postoperative days 1, 2, 4, and 8. Local (hepatic) and systemic inflammatory responses (interleukin-6 and tumor necrosis factor-alpha) during the postoperative time course were also determined. Data were analyzed using the Kruskal-Wallis test or univariate analysis of variance. RESULTS: Body weight gain, food intake, liver and spleen weights, as well as LFTs [except aspartate aminotransferase (AST)] did not differ among the four groups. The significant increase in the AST level following laparoscopy compared to the anesthesia-only group was found on postoperative days 1 and 2; however, a similar difference was not detected after laparotomy or i.p. endotoxin injection. Laparoscopy showed no alterations in the hepatic glycogen stores compared to anesthesia only, whereas laparotomy and endotoxinemia significantly reduced the hepatic glycogen stores on postoperative days 2 and 4. The systemic postoperative inflammatory response did not differ between laparotomy and laparoscopy, but it was higher in both groups than in anesthesia only. In rats treated with endotoxin, the systemic inflammatory response was even higher than in the two surgical groups. The hepatic inflammatory response did not differ between the four groups. CONCLUSION: This study shows a significant postoperative decrease in the hepatic glycogen content after laparotomy and i.p. endotoxin injection but not after laparoscopy. Food intake and inflammatory response cannot explain this difference between the two surgical groups, which suggests that alterations in the postsurgical hormonal stress response are the most likely explanation for these findings.

Animals↗
PubMed2005

Interactions of the ergosterol biosynthetic pathway with other lipid pathways.

Micro-organisms have recently received broad attention as sources of novel lipids. An increased understanding of the effects of fats and oils and their composition on the metabolism and on health has shifted the focus towards the use of lipids for disease treatment and prevention and for the promotion of good health. A large range of lipidic products produced by yeast is known today. Ergosterol and its metabolic precursors are major lipidic components of industrial and commercial interest. Having in mind the aim to increase the productivity of ergosterol and its precursor metabolites, both the knowledge of regulatory mechanisms of the biosynthetic pathway and its interactions with other lipid pathways like those of sphingolipids, phospholipids and fatty acids are crucial.

Ergosterol↗
PubMed2005

The nasal airflow in noses with septal perforation: a model study.

BACKGROUND: Septal perforation is a common clinical problem in rhinology. Affected patients suffer from a dry nose, crusts as well as recurrent epistaxis and sometimes an inspiratory whistle. The aim of this study was to investigate the underlying flow dynamic mechanisms. METHODS: The physical flow effects of such pathologies were examined in functional nose models (box models) and anatomically exact models of the nose. Therefore, septal perforations of different sizes and localisations were studied in straight and deviated nasal septa. RESULTS AND CONCLUSIONS: It could be seen that the localisation of the perforation has no impact on the flow pattern. In large septal perforations, the air jet collides with the posterior edge of the perforation and disintegrates turbulently. Since airflow is physiologically turbulent in the posterior part of the nose, posterior perforations do not cause clinical complaints. The inspiratory whistling sound during respiration is based on the principle of a lip whistle. Large perforations do not cause a whistling sound. The necessary high flow velocity needed in large perforations is usually not achievable.

Humans↗
PubMed2005

Investigations of the influence of external nose deformities on nasal airflow.

BACKGROUND: Abnormalities of the external shape of the nose are often felt as cosmetically disturbing. In many cases an additional hampering of the respiratory function of the nose is seen and causes pathological nasal airflow patterns. For the functional outcome of aesthetic-surgery of the nose, knowledge of nasal flow is essential. In the medical literature there are some discrepancies between the relationship of nasal shape and nasal flow. We investigated typical airflow patterns in different abnormalities of the external nose. METHODS: We performed fluid dynamic experiments on exact, anatomical nasal models and functional nasal models (so-called modified Mink boxes). We investigated the inspiratory flow pattern in nose-models with typical variations of the shape of the external nose. RESULTS AND CONCLUSIONS: There were typical airflow patterns for every external nasal abnormalities. The normal nose shows a disturbance of the streamlines over the entire nasal cavum. Under physiological flow velocities we find laminar and turbulent flow. The pathological variations of the nasal shape show mostly different airflow patterns and characteristics. The main reason for that is a deformed or anatomically false configurated inflow area (vestibulum, isthmus and anterior cavum). During rhinoplasty the reconstruction of the nasal inflow area has to be taken into account.

Humans↗
PubMed2005

Glial fibrillary acidic protein and myelin basic protein as markers for the immunochemical detection of bovine central nervous tissue in heat-treated meat products.

Because bovine central nervous tissue (CNT) is the main risk material in transmission of the infective agent of bovine spongiform encephalopathy, a suitable test is needed to enforce the ban on CNT in human foodstuffs in the United States and the European Union and to ensure that meat products are free of CNT To detect bovine CNT in heat-treated meat products, we used immunohistochemistry and Western blots with antibodies against glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP). Both antigens were resistant to processing methods used for meat products. The anti-GFAP antibody showed a high degree of tissue specificity, whereas the anti-MBP antibody had high species specificity, clearly differentiating between porcine and bovine CNT Therefore, immunochemistry performed with both proteins provides an effective means for detecting bovine CNT in meat products.

Animals↗
PubMed2003

Production of lipid compounds in the yeast Saccharomyces cerevisiae.

This review describes progress using the yeast Saccharomyces cerevisiae as a model organism for the fast and efficient analysis of genes and enzyme activities involved in the lipid biosynthetic pathways of several donor organisms. Furthermore, we assess the impact of baker's yeast on the production of novel, high-value lipid compounds. Yeast can be genetically modified to produce selected substances in relatively high amounts. A major advantage in choosing yeast as an object for metabolic engineering is the fact that the lipid pathways in this organism have been described in detail and are well characterized. We focus on the de novo production of three major families of lipid products. These are: (1) sterols, providing some previously known and some novel applications as examples of the lipid pathway enhancement that occurs naturally in yeast, (2) the reconstitution of the biosynthetic pathway of steroid hormones and (3) the biosynthesis of polyunsaturated fatty acids, leading to the biosynthesis of different omega-3 and omega-6 fatty acids which do not occur naturally in yeast. We utilize the current knowledge and point out perspectives and problems for future biotechnological applications in the field of lipid compounds.

Adrenal Cortex Hormones↗
PubMed2003

[Special features of intensive care of toxic shock syndrome. Review and case report of a TSST-1 associated toxic-shock syndrome with adult respiratory distress syndrome and multiple organ failure from a staphylococcal panaritium].

Toxic-shock-syndrome (TSS) is an acute febrile, exanthematous illness caused by toxins such as toxic-shock-syndrome-toxine-1 (TSST-1) and other endotoxines from staphylococcus aureus with an incidence of 0,5 per 100.000 inhabitants. Patients with menstrual toxic-shock-syndrome (menstrual-TSS) usually have TSS associated with menstruation and use of a vaginal device such as tampons. Other patients with non-menstrual toxic-shock-syndrome (non-menstrual-TSS) have a focus of staphylococcal infection such as a surgical wound infection or soft tissue abscess. TSS usually presents with fever, pharyngitis, diarrhoea, vomiting, myalgia and may progress rapidly (within hours) to signs of hypovolaemic hypotension and shock. In some cases TSS is associated with multisystem failure including shock, renal failure, myocardial failure and adult respiratory distress syndrome. In its acute phase the diagnosis of TSS is often uncertain because of its initial symptoms are non-specific and numerous conditions need to be considered in the differential diagnosis. But obviously less incidence, the signs and symptoms of toxic-shock-syndrome should be recognised early to permit successful therapy. The site of infection should be adequately drained and treated with antimicrobial therapy. Possible complications including ARDS and myocardial failure require a thorough understanding of its underlying pathophysiology to ensure appropriate intensive-care treatment. Only if appropriate therapy is instituted as early as possible, most of patients will be able to survive their toxic-shock-syndrome. In other cases TSS can be a rapidly progressive and perhaps lethal ending disease because of possible multiple organe failure such as ARDS.

Adolescent↗
PubMed2003

[Anesthesia in the breast feeding period. Excretion of anesthetic agents and adjuvants into breast milk and potential pharmacological side-effects on the suckling infant].

Whenever an anesthetic is needed during the breast feeding period, potential pharmacological side-effects imposed on the infant by any kind of anesthetic agent used during both general and regional anesthesia are in contrast to the potential beneficial effects of breast feeding for the infant and the mother. Despite an increasing knowledge and understanding of the mechanisms of excretion of drugs and their metabolites through breast milk, information about most anesthetic drugs are still either inconclusive or contradictory. Often it is impossible to decide whether a certain substance that is potentially excreted through breast milk might be harmless or harmful for the breast-fed infant. In addition to that only few anesthetic agents and drugs used in conjunction with an anesthetic are officially approved for use during pregnancy and the period of breast feeding and for medico-legal reasons pharmaceutical companies generally advise against the use of any of those drugs during this period. However, based on the knowledge of pharmacological properties of commonly used anesthetic agents it is reasonable to assume that continuing breast feeding in the immediate postoperative period after a single anesthetic can be considered safe for the infant since no adverse effects caused by or secondary to the single use of those drugs can be expected. Provided there is a careful choice of anesthetic drugs, there is no need to consider that a single general or regional anesthetic is an indication to stop breast feeding. Even planned elective surgical procedures do not need to be postponed. No scientifically based interval between surgery under general or regional anesthesia and resumption of breast feeding can be recommended. Instead current opinion is that breast feeding can be resumed as soon as the mother feels physically and mentally capable to do so.

Adjuvants, Anesthesia↗
PubMed2003

[The time-course of action of rapacuronium and mivacurium after early reversal following equally lasting relaxation].

This study was designed to compare the time course of action and the safety profile of Rapacuronium and Mivacurium in day case dental surgery. After Ethics Committee approval 61 healthy adult patients, scheduled for dental day case surgery, were randomised in an assessor-blinded manner to receive either 1.5 mg/kg Rapacuronium with and without 0.05 neostigmine 5 min later (19 patients each) or a total of 0.25 mg/kg Mivacurium (n = 16). Anaesthesia was induced using Propofol 2 - 5.1 mg/kg and Remifentanil 24 - 73 mcg/kg/h and maintained with Desflurane in N2O/O2 (2/1). Endotracheal intubation was performed when maximum blockade was achieved and scored by a blinded intubator. Neuromuscular block was monitored using the train-of-four response to supramaximal stimuli at the ulnar nerve every 15 seconds using acceleromyography (TOF Watch SX). Onset time, clinical duration (reappearance of the third twitch of a TOF-stimulation) and recovery to T4/T1 > 0.9 were recorded. Speed of recovery was evaluated by the time difference between reappearance of the third twitch and T4/T1 > 0.9. The intubating conditions at the time of maximum block revealed no statistically significant differences between the three groups. Changes in blood pressure, heart rate and airway pressure were not significant. Onset time in subjects who received Rapacuronium (99 +/- 29 s) was faster compared to the onset time in those who received Mivacurium (157 +/- 36 s). Also clinical duration was significantly shorter following Rapacuronium without reversal (12 +/- 4 min) as well as with reversal (9 +/- 1 min) compared with Mivacurium (21 +/- 5 min)). Patients treated with Rapacuronium and reversal recovered faster (14 +/- 8 min)) compared to the other two groups (Mivacurium: 20 +/- 6 min, Rapacuronium without reversal: 31 +/- 9 min). The fraction of clinical duration of the total duration was highest following Mivacurium (51 %) when compared with Rapacuronium/Neostigmine (43 %) and Rapacuronium (28 %).

Adolescent↗
PubMed2003

[Objectivation of nasal swelling--a comparison of four methods].

BACKGROUND: The measurement of the nasal swelling is very common in rhinologic diagnostics. For that, there are different methods available. Especially the nasal provocation test is important in this relationship. The measurement of the obstruction, caused by swelling of the nasal erectile tissue, allows a quantification of the allergic reaction. METHOD: We tested four different methods for objectivation of the mucosal swelling, which are used in the routine clinical examination: 1. acoustic rhinometry, 2. rhinoresistometry, 3. expiratory peak-flow-metry and 4. rhinomanometry. 40 volunteers were examined with the four methods before and after decongestion of the nose. We compared the results of each method (1. - 3.) with the results obtained by rhinomanometry. RESULTS: We found only a good correlation between rhinomanometry and rhinoresistometry. Both methods seem to be suited for the objectivation of nasal swelling.

Adult↗
PubMed2003

Stereotactic aspiration and fibrinolysis of spontaneous supratentorial intracerebral hematomas versus conservative treatment: a matched-pair study.

OBJECTIVES: Since introduction of stereotactic aspiration and fibrinolysis into the treatment of deep-seated intracerebral hematomas by Hondo and Matsumoto 1984 this method has become widely used, and satisfactory morphological results are achieved. Nevertheless, whether the outcome is improved has not yet been investigated. MATERIAL AND METHOD: 17 patients with spontaneous intracerebral hematomas have been treated surgically; after angiographic exclusion of a vascular malformation stereotactic aspiration and fibrinolysis with 3 mg rTPA was performed. Between 1992 and 1995 104 patients were treated conservatively according to best medical treatment. From this group "matched pairs" with the surgical patients were set up concurring in primary (consciousness, size and location of the hematoma) and secondary parameters (age, sex, ventricular hemorrhage). Endpoint of the study was the Glasgow outcome score (GOS) six months after treatment. Data were analyzed statistically and p < 0.05 was considered significant. RESULTS: In respect of primary parameters complete concurrence and regarding secondary parameters far-reaching concurrence was achieved. In no parameter the surgical and conservative group were significantly different from each other. Six months after the ictus no significant difference between surgical and conservative treatment concerning GOS could be established. CONCLUSION: These results indicate that patients do not benefit from stereotactic aspiration and fibrinolysis of putamenal hematomas. For a final treatment recommendation a prospective randomised trial is required.

Aged↗