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Biomedical subjects

C Müller

Publications and source records attributed to C Müller.

At least 73 records · Page 4Linked to original sources
PubMed2002

[Normal values for the internal thoracic artery by Doppler ultrasound and modification of the Doppler curve after bypass to the left anterior descending artery].

AIM: In coronary heart disease, the surgical therapy of choice is the construction of an artenal bypass of the left anterior descending artery (LAD) using the internal thoracic artery 8ITA). We define age dependent normal values for the ITA such as diameter of the lumen (LD), peak systolic (Vs) and diastolic (Vd) flow velocity and the ratio of these two values (SDR) measured by duplex ultrasound. Furthermore, the modification and pathological changes of the Doppler curve after minimal invasive bypass of the LAD (MIDCAB) are described. MATERIAL AND METHODS: 96 people, age 18 - 87 years, subdivided into 6 age groups were examined by duplex to define the normal values of the ITA, and 55 patients (mean age 63 +/- 10 years, 48 men, 7 women) were evaluated after MIDCAB-surgery to describe the postoperative modification of the Doppler curve. The examinations were performed using a 4 - 7 MHz linear ultrasound transducer in the right and left 1. or 2. intercostal space parasternally. RESULTS: In all 96 people, the ITA was detectable on both sides presenting a typical bi- or triphasic Doppler flow profile. A linear age dependent increase in the LD of 1.95 +/- 0.15 mm (right ITA) and 1.93 +/- 0.27 mm (left ITA) respectively to 2.65 +/- 0.48 mm and 2.55 +/- 0.43 mm was found. No significant side difference was found for Vs and Vd, nor were there any age dependent differences for Vs. The SDR showed an age dependent linear increase on the right side from 3.5 +/- 1.1 to 6.1 +/- 2.2, p < 0.0012, and on the left from 3.9 +/- 1.2 to 6.7 +/- 1.7, p < 0.0001. Postoperatively, the Doppler spectrum was modified into a mono- or biphasic Doppler curve with a reduced Vs and an increased Vd resulting in a significantly decreased SDR on the left side compared with the right side (1.3 +/- 0.8 vs. 5.4 +/- 2.0, p < 0.00001). Three patients with angiographically proven graft failure had an SDR of 2.6 - 5.2 (mean 3.8), as opposed to a value of < 2.0 in case of a patent bypass. An SDR > 2.0 has a sensitivity of 100 % and a specificity of 97 % in the detection of a haemodynamically relevant (>70 %) ITA-graft-stenosis. CONCLUSIONS: With rising age, there is an increase in the LD of the ITA and the peripheral resistance, expressed as SDR. After MIDCAB surgery the former triphasic Doppler flow curve changes into a mono- or biphasic curve corresponding to the coronary blood flow. An SDR >2.0 is a strong indicator of bypass failure.

Adolescent↗
PubMed2002

[Duplex ultrasound for follow-up examination after stent-angioplasty of ostial renal artery stenoses].

AIM: Renal artery stenosis (RAS) may lead to deterioration of renal function and/or hypertension. Stent angioplasty has become the method of choice in the treatment of atherosclerotic ostial RAS. We describe the changes of the following duplex parameters: intrarenal resistance index RI according to Pourcelot and the renal-aortic flow velocity ratio (RAR) directly after intervention and during follow-up (FU). We also examine the value of the method in detecting restenosis. PATIENTS AND METHODS: We present the results of a prospective study of 241 patients with stent angioplasty for the treatment of 355 severe RAS (extent of stenosis >/= 70 % of vessel diameter). Duplex examinations during FU were performed before discharge, after 6 and 12 months, and then annually resulting in 1292 examinations. RESULTS: RAR could be calculated in 98.9 % (1278/1292), RI was calculated in 100 % of the examinations. The RAR decreased significantly from 5.9 +/- 2.1 to 1.2 +/- 0.4 after intervention (p < 0.00001) with a slight increase during follow-up. RI increased significantly from 0.64 +/- 0.11 to 0.74 +/- 0.06 after intervention (p < 0.00001), equalling the RI of the contralateral side (0.74 +/- 0.07). During a mean FU of 27 +/- 15 months, 37 restenosis (10.4 %) and 12 re-restenosis were detected and confirmed angiographically, resulting in 48 reinterventions. In case of restenosis, RAR increased from 1.3 +/- 0.4 to 6.3 +/- 2.8 (p < 0.001) with a decrease to 1.3 +/- 0.6 after reintervention (p < 0.001), and RI decreased from 0.75 +/- 0.08 to 0.64 +/- 0.11 (p < 0.001) with an increase to 0.75 +/- 0.07 after reintervention (p < 0.001). CONCLUSIONS: Duplex ultrasound is a reliable method for FU of patients after renal artery stent-angioplasty and for detecting restenosis.

Adult↗
PubMed2002

Hepatopulmonary syndrome: prevalence and predictive value of various cut offs for arterial oxygenation and their clinical consequences.

BACKGROUND: The hepatopulmonary syndrome (HPS) is defined as the triad of liver disease, arterial deoxygenation, and pulmonary vascular dilatation. The reported prevalence of HPS in cirrhotic patients varies between 4% and 19%, and various threshold values defining arterial deoxygenation have been used and recommended previously. However, it is not known how the prevalence of HPS differs using different cut off values for arterial deoxygenation. METHODS: We studied 127 patients for the presence of HPS using transthoracic contrast echocardiography for detection of pulmonary vasodilation, pulmonary function tests, and blood gas analysis. RESULTS: Ninety eight patients were included in the study, of whom 33 (34%) had a positive contrast echocardiography. Using an increased alveolar-arterial difference for the partial pressure of oxygen (AaDO(2)) as an indication of hypoxaemia, the prevalence of HPS was considerably higher (>15 mm Hg, 32%; >20 mm Hg, 31%; and >age related threshold, 28%) than using reduced partial pressure of arterial oxygen (PaO(2)) as a threshold (<80 mm Hg, 19%; <70 mm Hg, 15%; and <age related threshold, 15%). For AaDO(2) as the cut off, the positive predictive value for a diagnosis of HPS was low (34%, 37%, and 53%, respectively). In contrast, PaO(2) as a cut off had considerably higher positive predictive values (44%, 93%, and 94%, respectively). Introducing PaO(2) <65 mm Hg as the cut off, the positive predictive value increased to 100%. Dyspnoea was more often present in patients with "clinically significant" HPS (57%) compared with "subclinical HPS" (8%), and patients without HPS (6%). The Child-Pugh score correlated significantly with the severity of HPS. Two of five liver transplanted patients with "subclinical HPS" had embolic brain infarcts, possibly induced by venous emboli passing through dilated intrapulmonary vessels. CONCLUSIONS: Defining arterial hypoxaemia in HPS by different, previously used, cut off values for arterial oxygenation leads to a wide variation in the prevalence of HPS in the same sample of cirrhotic patients.

Aged↗
PubMed2002

A method to assess biochemical activity of liver cells during clinical application of extracorporeal hybrid liver support.

Biochemical activity of a hybrid liver support system based on porcine liver cells was investigated in patients suffering from acute liver failure, coma stage III-IV Patient plasma was drawn systemically and after circulation through the bioreactor at four hour intervals. A method is used that takes into account the rate of plasma flow and the differences in plasma concentration systemically and after circulation through the liver support system to determine the net release or uptake of metabolites such as ammonia, urea and glucose. Urea release (mean 2.28+/-0.37 micromol/h/g cells) and ammonia uptake (mean 0.17+/-0.11 micromol/h/g cells) was seen during treatment, an active role of the system in glucose metabolism was observed. All patients were bridged successfully to liver transplantation.

Ammonia↗
PubMed2002

Preoperative evaluation of chronic alcoholics assessed for surgery of the upper digestive tract.

BACKGROUND: Alcoholics are at risk of developing major complications in the postoperative period. Adequate prophylactic treatment, as well as preoperative abstinence, can significantly decrease the rate of complications. However, the preoperative diagnosis of alcoholism is difficult to establish. The purpose of this study was to assess whether three preoperative visits, an alcohol-related questionnaire (CAGE), and the laboratory markers carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT) would increase the rate of detection of chronic alcoholics. METHODS: The study included the Departments of ENT, Facial and Maxillofacial Surgery, and General Surgery of a university hospital; 705 male patients were assessed for tumor surgery of the upper digestive tract and were allocated to 5 different groups. All patients were seen three times, and five different strategies were used to detect chronic alcoholics. The gold standard was the diagnosis of alcohol misuse made by an experienced (blinded) investigator according to the DSM-III-R. The main outcome measurements were the detection rates of the different test strategies. RESULTS: By clinical routine alone, only 16% were detected during the first visit and 34% after three visits. If the CAGE questionnaire was added, sensitivity increased to 64%. The further addition of GGT or CDT led to 80 and 85% detections, respectively. A combination of all tests had a sensitivity of 91%. CONCLUSIONS: To detect more alcoholic patients at risk for major complications, patients should be seen more often, and additional diagnostic tools such as the CAGE, CDT, and GGT should be used before surgery.

Adult↗
PubMed2001

Regulation and possible function of beta-catenin in human monocytes.

In this study, we demonstrate that adherence factors, serum constituents, LPS, and zymosan are capable of inducing a cellular accumulation of beta-catenin in human monocytes. Whereas adherence-dependent accumulation of beta-catenin can be blocked by wortmannin, an inhibitor of phosphatidylinositol 3-kinase, accumulation induced by the remaining stimuli cannot be prevented by inhibition of phosphatidylinositol 3-kinase, implying the involvement of beta-catenin in other not yet described signal transduction pathways. A role of beta-catenin in adherence-dependent processes by interacting with classical cadherins can be excluded as we could not detect cadherins in monocytes. To test whether it is possible that beta-catenin interacts with LEF/TCF (lymphoid enhancer factor/T cell factor) transcription factors, we studied the expression of this protein family. TCF-4 was identified as the LEF/TCF transcription factor present in human monocytes. However, neither cellular induction of beta-catenin nor cotransfection experiments with beta-catenin conducted in the monocytic cell line THP-1 resulted in the activation of a LEF/TCF-dependent promoter, suggesting the requirement of additional signals. Concurrent with this suggestion, we found that LPS and zymosan, two physiological inducers of beta-catenin, caused an increase in the expression of genes that are positively regulated by beta-catenin.

Androstadienes↗
PubMed2001

[Long-term follow-up of 100 patients with acute myocardial infarction treated with angioplasty].

BACKGROUND: There is little information available on long-term follow up of patients treated with primary angioplasty for acute myocardial infarction. MATERIAL AND METHODS: 100 consecutive patients with acute ST-elevation myocardial infarction and symptoms of less than six hours' duration were treated with primary angioplasty. Clinical examination was performed in 97 patients and exercise stress test in 74 patients 11-37 months (mean 20 months) later. Patients were observed for survival up to 48 months. RESULTS: 24 patients had been rehospitalized, 16 because of chest pain. 77 patients were treated with beta blocker, 83 with statins, and 95 with antithrombotic medication. 84 patients were in NYHA (New York's Heart Association's classification's) class I at follow-up examination. Three patients died. 11 patients had a serious event, reinfarction (n = 3) or need for revascularization (n = 8) during the first 13 months. Total cumulative mortality rates after one and three years were 3% (95% CI 1-8) and 11% (95% CI 6-19). INTERPRETATION: The good initial results in primary angioplasty are maintained in long-term follow-up. This is in accordance with reports from centres abroad.

Adult↗
PubMed2001

Amplification and overexpression of PRUNE in human sarcomas and breast carcinomas-a possible mechanism for altering the nm23-H1 activity.

PRUNE, the human homologue of the Drosophila gene, is located in 1q21.3, a region highly amplified in human sarcomas, malignant tumours of mesenchymal origin. Prune protein interacts with the metastasis suppressor nm23-H1, but shows impaired affinity towards the nm23-H1 S120G mutant associated with advanced neuroblastoma. Based on these observations, we previously suggested that prune may act as a negative regulator of nm23-H1 activity. We found amplification of PRUNE in aggressive sarcoma subtypes, such as leiomyosarcomas and malignant fibrous histiocytomas (MFH) as well as in the less malignant liposarcomas. PRUNE amplification was generally accompanied by high mRNA and moderate to high protein levels. The sarcoma samples expressed nm23-H1 mostly at low or moderate levels, whereas mRNA and protein levels were moderate to high in breast carcinomas. For the more aggressive sarcoma subtypes, 9/13 patients with PRUNE amplification developed metastases. A similar situation was observed in all breast carcinomas with amplification of PRUNE. Infection of NIH3T3 cells with a PRUNE recombinant retrovirus increased cell proliferation. Possibly, amplification and overexpression of PRUNE has the same effect in the tumours. We suggest that amplification and overexpression of PRUNE could be a mechanism for inhibition of nm23-H1 activity that affect the development or progression of these tumours.

3T3 Cells↗
PubMed2001

Reliable in vitro measurement of nitric oxide released from endothelial cells using low concentrations of the fluorescent probe 4,5-diaminofluorescein.

4,5-Diaminofluorescein (DAF-2) and its membrane-permeable derivate DAF-2 diacetate are fluorescent probes that have been developed to perform real-time biological detection of nitric oxide (NO). Their use for intracellular imaging, however, has recently been seriously questioned and data using DAF-2 for extracellular NO detection at low levels, as for example released from endothelial cells, are rare. Here we show that a reliable detection of low levels of NO in biological systems by DAF-2 is possible (a) by using low DAF-2 concentrations (0.1 microM) and (b) by subtracting the DAF-2 auto-fluorescence from the measured total fluorescence. The described method allows easy real-time detection of endothelial NO formation.

Cell Line↗
PubMed2001

Intraoperative measurement of intact parathyroid hormone in renal hyperparathyroidism by an inexpensive routine assay.

Although the kinetics of intraoperative intact parathyroid hormone (iPTH) are well characterised in primary hyperparathyroidism, no data are available for patients with renal hyperparathyroidism and renal insufficiency, partially because of the high costs of intraoperative quick iPTH measurement. Therefore we evaluated an inexpensive laboratory test with a duration of 18 min for intraoperative use and measured iPTH intraoperatively in 34 patients with renal hyperparathyroidism. Samples were taken before and 5 min and 15 min after parathyroid resection. Blood samples were put on ice immediately and sent to the hospital central laboratory via a pneumatic tube system. The first 76 probes were measured in parallel using three assays: the Nichols Quick PTH, the Roche Elecsys and the Biermann Immulite assay. The subsequent samples were only measured using the Elecsys assay. Determination of iPTH from 76 samples showed a correlation coefficient of 0.997 between the Immulite and Elecsys assay and a correlation coefficient of 0.987 for the Nichols Quick PTH and the Elecsys test. In renal hyperparathyroidism the mean iPTH was 26+/-2% of the starting value 5 min after subtotal parathyroidectomy and 18+/-2% after 15 min. Renal function influenced absolute iPTH values in patients with renal hyperparathyroidism but not relative changes. In patients with terminal renal insufficiency iPTH decreased from 615+/-57 pg/m before preparation to 109+/-13 pg/ml 15 min after subtotal resection. In contrast in patients after kidney transplantation iPTH decreased from a lower starting value of 341+/-94 pg/ml to 58+/-9 pg/ml after 15 min. The iPTH kinetics showed a biphasic clearance of iPTH with an initial dominant half-life of 3.2 min and a terminal half-life of 29.2 min. Half-life did not correlate with renal function. All operations were successful as indicated by an adequate drop in PTH (from 709+/-92 pg/ml preoperatively to 22+/-6 pg/ml at discharge) and calcium (from 2.57+/-0.04 mmol/l to 2.32+/-0.04 mmol/l). In conclusion, intraoperative measurement of iPTH is also reliable in patients with renal hyperparathyroidism. Elimination kinetics are similar to that in patients with primary disease. However, the half-life was not influenced by renal function. The availability of a quick, inexpensive, routine iPTH test might expand its use to renal hyperparathyroidism, specifically for surgical decisions in problem cases.

Female↗
PubMed2001

Peripheral blood cell bulk cultures are not suitable for the analysis of the genetic control of T-cell cytokine function.

Recently evidence has been provided for a genetic control of T-cell dependent cytokine production by HLA-class II. Candidate genes in multiple sclerosis, a T-cell mediated autoimmune disease, are the disease-associated DR2, DQ6, Dw2 haplotype. Previous observations by us and others imply a HLA-DR2 dependent propensity of antigen-specific T-cell lines to produce increased amounts of TNF-alpha/beta. Here, we tested a possible association between HLA or disease status with cytokine production employing the simple and widely used method of bulk cultures. Peripheral blood cells of 48 patients and 68 healthy individuals were analyzed. We observed no significant differences of the cytokine production in relation to disease status or any HLA polymorphism. Our data indicate that, in contrast to monoclonal T-cell cultures, bulk cultures are not suitable to detect immunogenetic control of T-cell function.

Alleles↗
PubMed2001

Value of cardiac troponin I and T for selection of heart donors and as predictors of early graft failure.

BACKGROUND: Cardiac troponin I and T (cTnI and cTnT) are sensitive and specific markers of myocardial damage. We evaluated them for the selection of heart donors and as predictors of early graft failure after heart transplantation. METHODS: cTnI, cTnT, myoglobin, and creatine kinase (CK) levels and its isoenzyme MB (CKMB) activity and mass were measured in serum samples immediately before opening the pericardium from 126 consecutive brain-dead multi-organ donors over 10 years of age inspected by our harvesting team. Donors with serum creatinine >2.0 mg/dL (n=6) were excluded from the analysis. Donors for high-urgency status recipients (n=2) were also excluded. The remaining donors were retrospectively divided into three groups: group I (n=68), grafts with good function; group II (n=11), grafts with impaired function; and group III (n=39), grafts not accepted for transplantation. RESULTS: No differences in donor and recipient characteristics were found among the groups. The mean values of cTnI (0.36+/-0.88 microg/L, 4.45+/-3.28 microg/L, and 3.02+/-7.88 micog/L, respectively) and cTnT (0.016+/-0.029 microg/L, 0.134+/-0.114 microg/L, and 0.123+/-0.245 microg/L, respectively) were lower in group I when compared with groups II or III (cTnI: P<0.0001, P=0.018; cTnT: P<0.0001, P=0.012). The cTnI value was higher in group II compared with group III (P=0.023). The cTnT values were similar in groups II and III. A cTnI value >1.6 microg/L as a predictor of early graft failure had a specificity of 94%, and a cTnT value of >0.1 microg/L had a specificity of 99%. The odds ratio for the development of acute graft failure after heart transplantation was 42.7 for donors with cTnI >1.6 microg/L and 56.9 for donors with cTnT >0.1 microg/L. No differences of myoglobin, CKMB activity, or CKMB/CK ratio were found among the groups. CONCLUSIONS: Significantly higher cTnI and cTnT values were found in peripheral blood at the time of explantation in donors of hearts with subsequently impaired graft function and in not accepted donors. cTnI and cTnT are useful as additional parameters for heart donor selection.

Adult↗
PubMed2001

IL-9 and IL-13 production by activated mast cells is strongly enhanced in the presence of lipopolysaccharide: NF-kappa B is decisively involved in the expression of IL-9.

Mast cells, due to their ability to produce a large panel of mediators and cytokines, participate in a variety of processes in adaptive and innate immunity. Herein we report that in primary murine bone marrow-derived mast cells activated with ionomycin or IgE-Ag the bacterial endotoxin LPS strongly enhances the expression of IL-9 and IL-13, but not IL-4. This costimulatory effect of LPS is absent in activated mast cells derived from the LPS-hyporesponsive mouse strain BALB/c-LPS(d), although in these cells the proinflammatory cytokine IL-1 can still substitute for LPS. The enhanced production of mast cell-derived IL-13 in the presence of IL-1 is a novel observation. Coactivation of mast cells with LPS leads to a synergistic activation of NF-kappa B, which is shown by an NF-kappa B-driven reporter gene construct. In the presence of an inhibitor of NF-kappa B activation, the production of IL-9 is strongly decreased, whereas the expression of IL-13 is hardly reduced, and that of IL-4 is not affected at all. NF-kappa B drives the expression of IL-9 via three NF-kappa B binding sites within the IL-9 promoter, which we characterize using gel shift analyses and reporter gene assays. In the light of recent reports that strongly support critical roles for IL-9 and IL-13 in allergic lung inflammation, our results emphasize the potential clinical importance of LPS as an enhancer of mast cell-derived IL-9 and IL-13 production in the course of inflammatory reactions and allergic diseases.

Adjuvants, Immunologic↗
PubMed2001

[Hundred patients with acute myocardial infarction treated with primary angioplasty].

BACKGROUND: Much attention has lately been focused on primary angioplasty in the treatment of acute myocardial infarction. This report describe our results in 100 patients. MATERIAL AND METHODS: 100 consecutive patients with acute ST elevation myocardial infarction and a history of less than six hours were treated with primary angioplasty. The mean time from start of symptoms until establishment of reperfusion of the infarct related artery was 224 minutes; "the door-to-balloon" time was 69 minutes. RESULTS: Angioplasty was successful in 95% of all patients. Mean ejection fraction measured before discharge in 71 patients was 56%. Hospital and 30-days' mortality was 1%. New revascularization was needed in 6%. Average observation period in the coronary care unit was 1.8 days; no patient needed treatment for ventricular arrhythmias after angioplasty. The first 24 hours 24% had symptomatic congestive heart failure, reduced to 11% at hospital discharge on day 6. Acute rehospitalization within the first 30 days was necessary in 7%, but only in 2% for chest pain. INTERPRETATION: Our results are comparable to those of other high volume centres and show well preserved ventricular function and low hospital and 30-days' morbidity and mortality.

Adult↗
PubMed2001

Transition of adult patients with cystic fibrosis from paediatric to adult care--the patients' perspective before and after start-up of an adult clinic.

UNLABELLED: Although most patients with cystic fibrosis (CF) survive into adulthood, many CF centres are still run by paediatricians. A transition programme from the paediatric CF unit to a newly established CF clinic at the Department of Internal Medicine was carried out for the whole group of patients > or =18 years. We aimed to evaluate our patients' opinion of the transition by analysing the results of two surveys performed before and after the transition. Nine months before the transition, we mailed an anonymous questionnaire. Statements regarding the forthcoming transition were to be answered on scales from 1 to 4, and the patients had to check a list of adjectives describing the current treatment in the paediatric CF centre as well as the presumed care in the adult unit. Fifteen months after the transition, a second survey with similar questions was carried out. RESULTS: 44 of 68 patients (65%) aged 18 to 33 years replied to the first and 56% of patients to the second questionnaire. Mean duration of treatment at the paediatric CF centre was 7.5 years (range: 1 to 22 years). Twelve patients each were classified as supporters or opponents of the transition, the remaining patients as intermediates. Older patients and those who had not required hospitalisation during the preceding year had a more positive attitude to the transition (p <0.05). There was a linear relationship between the transition attitude score and the presumed quality of care in the Internal Medicine Department (r = 0.62, p <0.001), but no relation to the quality of present paediatric care (r = -0.09, p = 0.59). In the second survey, patients rated the quality of care in the adult CF unit better than prior to the transition. CONCLUSIONS: The transition from paediatric to a newly established adult CF centre was accepted by most adult CF patients. Thorough training of all staff of the new adult unit and a close co-operation between both departments are pre-requisites to guarantee a smooth transition of all patients.

Adolescent↗
PubMed2001

Heterologous inhibition of G protein-coupled receptor endocytosis mediated by receptor-specific trafficking of beta-arrestins.

We have observed an unexpected type of nonreciprocal "cross-regulation" of the agonist-induced endocytosis of G protein-coupled receptors by clathrin-coated pits. Isoproterenol-dependent internalization of beta2-adrenergic receptors in stably transfected HEK293 cells was specifically blocked (>65% inhibition) by vasopressin-induced activation of V2 vasopressin receptors co-expressed at similar levels. In contrast, activation of beta2 receptors caused no detectable effect on V2 receptor internalization in the same cells. Several pieces of evidence suggest that this nonreciprocal inhibition of endocytosis is mediated by receptor-specific intracellular trafficking of beta-arrestins. First, previous studies showed that the activation of V2 but not beta2 receptors caused pronounced recruitment of beta-arrestins to endocytic membranes (Oakley, R. H., Laporte, S. A., Holt, J. A., Barak, L. S., and Caron, M. G. (1999) J. Biol. Chem. 274, 32248-32257). Second, overexpression of arrestin 2 or 3 (beta-arrestin 1 or 2) abolished the V2 receptor-mediated inhibition of beta2 receptor internalization. Third, mutations of the V2 receptor that block endomembrane recruitment of beta-arrestins eliminated the V2 receptor-dependent blockade of beta2 receptor internalization. These results identify a novel type of heterologous regulation of G protein-coupled receptors, define a new functional role of receptor-specific intracellular trafficking of beta-arrestins, and suggest an experimental method to rapidly modulate the functional activity of beta-arrestins in intact cells.

Arginine Vasopressin↗
PubMed2001

Selective fortification of lysinoalanine, fructoselysine and N epsilon-carboxymethyllysine in casein model systems.

In the present study, a promising strategy to study nutritional effects of selected chemical reaction products formed in heat treated protein containing foods is addressed. In due course, a selective fortification of different marker compounds for lysine damage in casein-sugar mixtures was performed to provide model systems being applicable to investigate biological effects of the cross-link lysinoalanine (LAL), the MRPs fructoselysine (FL) and N epsilon-carboxymethyllysine (CML) in a casein-linked preparation. The three different model proteins, casein-LAL, casein-FL and casein-CML were prepared by heating casein either in strong alkaline conditions at 105 degrees C for 1 h, in the presence of glucose at 65 degrees C for 68 h, or in the presence of glyoxylic acid at 37 degrees C for 19 h. Finally, the degree of lysine modification achieved was 39%, 75% and 55% for the casein-LAL, casein-FL and casein-CML, respectively. The calculation of lysine recovery and the respective analysis of each single modified casein (LAL-, FL- and CML-MP) for the selected fortified compound and each other compound vice versa proved that the individual procedure provides a specific fortification for LAL, FL and CML, respectively. The modified proteins are suitable as reference model proteins to be investigated for specific biological and toxicological effects of casein-linked LAL, FL and CML.

Caseins↗