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Biomedical subjects

C Adam

Publications and source records attributed to C Adam.

At least 19 recordsLinked to original sources
PubMed2006

The increased angiotensin II (type 1) receptor density in myocardium of type 2 diabetic patients is prevented by blockade of the renin-angiotensin system.

AIMS/HYPOTHESIS: The angiotensin II (type 1) (AT1) receptor mediates many biological effects of the renin-angiotensin system (RAS), leading to remodelling of cardiac tissue. The present study was designed to analyse changes in the function and expression of the AT1 receptor as principal effector of the RAS in myocardium from type 2 diabetic patients compared with non-diabetic myocardium as control. In addition, we determined the effect of treatment with ACE inhibitors or AT1 receptor blockers on expression levels of the receptor in diabetic patients. METHODS: Gene expression of the AT1 receptor was analysed by quantitative RT-PCR and protein expression was determined by immunoblot analysis in human right atrial myocardium. We investigated functional coupling of the receptors by measuring contractility in isolated trabeculae stimulated with increasing concentrations of angiotensin II. RESULTS: Diabetic myocardium showed a significant increase in protein expression (170 +/- 16% of control) and median mRNA expression (186% of control) of the AT1 receptor. The additional receptors were functionally coupled, resulting in a stronger inotropic response upon stimulation with angiotensin II (89 +/- 5.5% vs 29 +/- 1.6% in controls), whereas receptor affinity was similar in both groups. However, myocardium from diabetic patients treated with ACE inhibitors or AT1 receptor blockers showed no increase in AT1 receptor expression. CONCLUSIONS/INTERPRETATION: AT1 receptor expression in myocardium of type 2 diabetic patients is dynamic, depending on the level of glycaemic control and the activity of the RAS. These findings could at least in part explain the strong therapeutic benefit of RAS inhibition in diabetic patients.

Aged↗
PubMed2006

Towards a proper estimation of phase synchronization from time series.

In experimental synchronization studies a continuous phase variable is commonly estimated from a scalar time series by means of its representation on the complex plane. The aim is to obtain a pair of functions [A(t), phi(t)] defining its instantaneous amplitude and phase, respectively. However, any arbitrary pair of functions cannot be considered as the amplitude and the phase of the real observable. Here, we point out some criteria that the pair [A(t), phi(t)] must observe to unambiguously define the instantaneous amplitude and phase of the observed signal. In this work, we illustrate how the complex representation may fail if the signal possesses a multi-component or a broadband spectra. We also point out a practical procedure to test whether a signal, not displaying a single oscillation at a unique frequency, has a narrow-band behavior. Implications for the study of phase interdependencies are illustrated and discussed. Phase dynamics estimated from electric brain activities recorded from an epileptic patient are also discussed.

Algorithms↗
PubMed2006

[Therapy strategies for advanced renal cell carcinoma].

The therapeutic regimen for metastatic renal cell cancer has changed substantially in the last years. Formerly, metastatic disease was regarded as being inoperable and had a disastrous prognosis. Nowadays, radical nephrectomy is the accepted urologic-oncologic standard therapy in metastatic primaries, if technically feasible. A complete resection of metastases may be curative, or can achieve a substantial palliative benefit. A better understanding of prognostic parameters helps in the selection of patients with a chance of benefiting from systemic immunochemotherapy. For patients with rapidly progressing tumors or sarcomatoid dedifferentiation, new effective chemotherapy regimens are available. New angiogenesis inhibitors such as sutent, avastin or sorafenib can potentially be effectively used in future therapeutic regimens.

Angiogenesis Inhibitors↗
PubMed2006

[How do the temporal lobes communicate in medial temporal lobe seizures?].

INTRODUCTION: Spatial and temporal patterns of the spread of partial epileptic seizures depend on the site from which they originate. Characterising seizure propagation patterns may help to better define the seizure focus. In medial temporal lobe epilepsies, seizure propagation to the contralateral temporal lobe is especially studied. STATE OF THE ART: Intracranial EEG records permit more precise definition of patterns of contralateral propagation in medial temporal lobe epilepsies. Several pathways have been implicated, sometimes differently in distinct studies, in propagation to the contralateral temporal lobe: the three commissures (the corpus callosum, the ventral hippocampal commissure and the anterior commissure, which link the temporal lobes) and an indirect circuit via the frontal lobes. Delays measured for contralateral propagation of a seizure of temporo-limbic origin vary significantly around a mean value of about 30 seconds. This slow spread may depend in part on the relatively small size of human commissural projections from the amygdalo-hippocampal formation, which largely originate in the presubiculum. However, a larger commissural projection pathway originates in the paralimbic medial temporal lobe and electrical stimulation of the anterior perirhinal cortex can induce contralateral epileptic discharges with delays as short as 100 ms (Adam et al., 2004). Thus, seizure activity emerging from anterior paralimbic regions can propagate rapidly to the contralateral medial temporal lobe via the anterior commissure. PERSPECTIVES: While the propagation of medial temporal lobe seizures is still debated, further studies are merited since the extent and speed of spread governs the electro-clinical semiology of seizures and our ability to identify their initiation site. CONCLUSIONS: We review anatomical (Demeter et al., 1990) and neurophysiological (Wilson et al., 1990) data for a dual inter-temporal propagation of medial temporal lobe seizures at different speeds and via different pathways.

Brain Mapping↗
PubMed2006

Impact of introducing a sedation management guideline in intensive care.

To ensure that sedative agents in the intensive care unit are used for maximum benefit, a guideline that promotes the accurate and continuous assessment of patients' needs is indicated. This observational 24-month prospective study investigated the effect of introducing a sedation management guideline into a 10-bedded multidisciplinary intensive care unit on length of stay, severity of illness, mortality and the number of bed days provided. Costs for all sedative drugs were calculated as cost per bed day. Intensive care unit mortality remained constant before and after guideline introduction. The length of stay of non-cardiac surgery patients was mean (SD) 4.6 (4.4) and 5.1 (4.3) days, respectively (p = 0.2). Monthly sedative cost before guideline introduction was pound 6285 compared to pound 3629 afterwards (p< or =0.0001), representing a real saving of pound 63 759 in sedative costs over the 2 years following introduction of the guideline. Guideline-directed management for sedation significantly reduces the cost of sedative drugs per bed day without any negative effect on length of ICU stay and outcome.

Adult↗
PubMed2005

Enhanced post-denitrification without addition of an external carbon source in membrane bioreactors.

This study investigates a post-denitrification process without the addition of an external carbon source combined with an enhanced biological phosphorus removal (EBPR) in a membrane bioreactor (MBR). Three trial plants, with two different process configurations, were operated on two different sites, and a variety of accompanying batch tests were conducted. It was shown that even without dosing of an external carbon source, denitrification rates (DNR) much above endogenous rates could be obtained in post-denitrification systems. Furthermore, the anaerobic reactor located ahead of the process had a positive impact on the DNR. Given these surprising results, the project team decided to identify the carbon source used by the microorganisms in the post-denitrification process. Batch tests could demonstrate that lysis products do not play a major role as a C-source for post-denitrification. The following hypothesis was proposed to explain the observations: the glycogen, internally stored by the substrate accumulating bacteria, if anaerobic conditions are followed by aerobic conditions could act as carbon source for denitrification in post-denitrification system. First exploratory batch tests, where the glycogen evolution was monitored, corroborate this assumption.

Bacteria, Aerobic↗
PubMed2004

Reactivity of sulfur nucleophiles with N-methyl-N-nitroso-p-toluenesulfonamide.

The transfer of the nitroso group from N-methyl-N-nitroso-p-toluenesulfonamide (MNTS) to cysteine (CYS) and 2-aminoethanethiol (AET) has been studied in a pH range between pH = 7 and pH = 13. Kinetic results clearly indicate that both nucleophiles react through the corresponding thiolate to give the corresponding nitrosothiol. The existence of two (AET) or three (CYS) macroscopic acidity constants has been kinetically evidenced and the nitrosation rates of the corresponding bases have been identified. Nitrosation rate constants of the different species present in the reaction medium have been determined and a Bronsted-type plot has been established giving a beta(nuc) value approximately equal to 0.08 clearly different from the values of beta(nuc) approximately equal to 0.7 obtained in the nitrosation of primary and secondary amines by MNTS. The low beta(nuc) value has been attributed to the need for previous desolvation of the nucleophile.

Journal Article↗
PubMed2004

Levetiracetam in progressive myoclonic epilepsy: an exploratory study in 9 patients.

The authors conducted an open study of levetiracetam as add-on therapy in nine patients with well-defined progressive myoclonic epilepsies and refractory myoclonus. Myoclonus was evaluated semiquantitatively (territory, intensity, daily living activities). Five patients had improvement of their myoclonus score. Levetiracetam may benefit myoclonus in progressive myoclonic epilepsy.

Activities of Daily Living↗
PubMed2004

[Complete remission of pulmonary metastasis from renal cell carcinoma through inhalation therapy with Interleukin-2 after unsuccessful systemic immunochemotherapy].

Therapy of metastasized renal cell carcinoma is based on systemic immunotherapeutic strategies, if surgical resection is not possible. The costs of inhalative Interleukin-2 therapy in case of pulmonary metastases as off-label-use are not accepted by compulsory health insurance yet.We report on a female patient with pulmonary metastasized renal cell carcinoma who had tumor progression after immunochemotherapy that followed complete response after inhalative therapy with Interleukin-2.

Administration, Inhalation↗
PubMed2004

A short form of the Fagerström Test for Nicotine Dependence and the Heaviness of Smoking Index in two adult population samples.

Few data exist about the Fagerström Test for Nicotine Dependence (FTND) and the Heaviness of Smoking Index (HSI) from population samples. The goal was to prove to what degree (1) a reduced item solution of the FTND and (2) the HSI represent the FTND. Two randomized adult population samples were used from northern Germany. Sample 1 included 1462 and sample 2 included 1042 current daily cigarette smokers aged 20-64 years with FTND data. The results show that four items of the FTND as well as the HSI represent the FTND. It is concluded that both are valid measures of the urge to smoke and the tobacco-smoke-seeking behavior.

Adult↗
PubMed2004

A finite element formulation and program to study transient swelling and load-carriage in healthy and degenerate articular cartilage.

The theory of poroelasticity is extended to include physico-chemical swelling and used to predict the transient responses of normal and degenerate articular cartilage to both chemical and mechanical loading; with emphasis on isolating the influence of the major parameters which govern its deformation. Using a new hybrid element, our mathematical relationships were implemented in a purpose-built poroelastic finite element analysis algorithm (u-pi-c program) which was used to resolve the nature of the coupling between the mechanical and chemical responses of cartilage when subjected to ionic transport across its membranous skeleton. Our results demonstrate that one of the roles of the strain-dependent matrix permeability is to limit the rate of transmission of stresses from the fluid to the collagen-proteoglycan solid skeleton in the incipient stages of loading, and that the major contribution of the swelling pressure is that of preventing any excessive deformation of the matrix.

Adaptation, Physiological↗
PubMed2003

[Hemangiomas and vascular malformations in the area of the head and neck].

The treatment of paediatric patients with extended vascular anomalies in the head and neck requires a multidisciplinary approach involving paediatricians, maxillofacial surgeons, dermatologists and radiologists. Therapeutic strategies are based on an internationally accepted classification of vascular anomalies, which distinguishes haemangiomas and vascular malformations. Whereas haemangiomas are endothelial proliferations, vascular malformations are considered to be developmental anomalies which are classified into high-flow or low-flow lesions and, according to their vascular channels, into capillary, lymphatic or venous malformations. In this review we present guidelines for the diagnostic assessment of paediatric patients with vascular anomalies in the head and neck region. The indications for treatment are discussed and therapeutic options are outlined.

Adolescent↗
PubMed2003

Enhanced biological phosphorus removal process implemented in membrane bioreactors to improve phosphorous recovery and recycling.

The enhanced biological phosphorus removal (EBPR) process was adapted to membrane bioreactor (MBR) technology. One bench-scale plant (BSP, 200-250 L) and two pilot plants (PPs, 1,000-3,000 L each) were operated under several configurations, including pre-denitrification and post-denitrification without addition of carbon source, and two solid retention times (SRT) of 15 and 26 d. The trials showed that efficient Bio-P removal can be achieved with MBR systems, in both pre- and post-denitrification configurations. EBPR dynamics could be clearly demonstrated through batch-tests, on-line measurements, profile analyses, P-spiking trials, and mass balances. High P-removal performances were achieved even with high SRT of 26 d, as around 9 mgP/L could be reliably removed. After stabilisation, the sludge exhibited phosphorus contents of around 2.4%TS. When spiked with phosphorus (no P-limitation), P-content could increase up to 6%TS. The sludge is therefore well suited to agricultural reuse with important fertilising values. Theoretical calculations showed that increased sludge age should result in a greater P-content. This could not be clearly demonstrated by the trials. This effect should be all the more significant as the influent is low in suspended solids.

Bacteria↗
PubMed2003

Cost effective and advanced phosphorus removal in membrane bioreactors for a decentralised wastewater technology.

Future stringent phosphorus regulations (down to 50 microg/L in some cases) together with the availability of more cost effective and/or innovative membrane processes, are the bases for this project. In contrast to conventional activated sludge plants, process parameters are not optimised and especially enhanced biological phosphorus (Bio-P) removal in membrane bioreactors (MBRs) are not proven yet. Current practice of P-removal in MBRs is the addition of coagulants in a co-precipitation mode. Enhanced biological phosphorus removal, when adapted to MBR technology, might be a cost-effective process. For very stringent effluent criteria additional P-adsorption on activated clay after membrane filtration can be also an interesting solution. The objective of this research project is to identify and test various phosphorus removal processes or process combinations, including MBR technologies. This should enable us to establish efficient and cost effective P-removal strategies for upgrading small sewage treatment units (up to 10,000 PE), as needed in some decentralised areas of Berlin. In particular, enhanced Bio-P removal technology was developed and optimised in MBR. Combinations of co-precipitation and post-adsorption will be tested when low P-values down to 50 microg/L are required in the effluent. One MBR bench-scale plant of 200 to 250 L and two MBR pilot plants of 1 to 3 m3 each were operated in parallel to a conventional wastewater treatment plant (Ruhleben WWTP, Berlin, Germany). The MBR bench-scale and pilot plants were operated under sludge ages of respectively 15 and 25 days. In both cases, Bio-P was possible, and phosphorus effluent concentration of about 0.1 mg/L could be achieved. A similar effluent quality was observed with the conventional WWTP. Investigations with lab columns indicated that P-adsorption could lead to concentrations down to 50 microg/L and no particle accumulation occurred in the filter media. The three tested materials exhibited great differences in break-through curves. Granulated ferric hydroxyde (GEH) showed higher capacity than activated alumina and FerroSorpPlus.

Adsorption↗
PubMed2002

[Telerobotic surgery between Baltimore and Munich].

The rapid development of laparoscopy in urology necessitates the training of specialists to guarantee the high standard of patient care. The real-time data communication of medical information between physicians in different locations is known as telemedicine. Telementoring describes the assistance of an experienced surgeon, while telerobotics requires the use of robots. Two robots, the established AESOP and the PAKY + RCM developed at the Johns Hopkins Hospital (JHH), were used to perform a telerobotic laparoscopic renal cyst ablation in cooperation between Baltimore and Munich. The telementor maneuvered the robots over a distance of 8000 km using eight ISDN lines and a PC. AESOP moved the camera, while PAKY allowed the use of a fan retractor in the abdomen. The telerobotic operation was performed without complications or system and communication failures. Telementoring can be used for training purposes but also for consultation between specialists in emergency settings.

Baltimore↗
PubMed2002

Effects of Cd and Zn waterborne exposure on the uptake and depuration of 57Co, 110mAg and 134Cs by the Asiatic clam (Corbicula fluminea) and the zebra mussel (Dreissena polymorpha)--whole organism study.

Groups of zebra mussels (Dreissena polymorpha) and asiatic clams (Corbicula fluminea) were exposed to cadmium and zinc with the aim of studying the effect of these metals on the 57Co, 110Ag and 134Cs uptake and depuration by these freshwater bivalves. In the presence of zinc, the 57Co concentration factor for the whole organism of the two species was halved, notably because of a decrease of the uptake parameter. Conversely, Zinc and the Cd + Zn mixture increased the 110mAg uptake process by clams and mussels. The two metals also increased the depuration of this radionuclide in mussels, whereas this phenomenon was only observed in clams exposed to cadmium. In comparison with 57Co and 110mAg, the 134Cs bioconcentration was 5-10 times lower in D. polymorpha and not detected in C. fluminea. This weak contamination by this radionuclide resulted from a lower uptake and a higher depuration parameters.

Animals↗