Analysis of Epitopes on the Unrelated Proteins Thyrotropin Receptor and alpha1-Antitrypsin which are Recognized by A10 Monoclonal Antibody

In a previous study, we noticed an unexpected reaction of an antithyrotropin receptor ectodomain (ETSHR)-reactive monoclonal antibody, A10, with alpha1-antitrypsin (antitrypsin). Presently, we decided to probe the structural basis of this cross-reactivity. Recombinant ETSHR, antitrypsin, synthetic peptides corresponding to the region of similarity in these proteins (EEDFRV and EEDFHV, respectively) and a set of peptides related to this region, N- and C-terminally elongated, were used in the study. Comparing the values of the dissociation constants, we found that the affinity of peptides corresponding to the region of similarity to monoclonal antibody A10 was the same in spite of a difference in one residue (R 38 in ETSHR and H 209 in antitrypsin), whereas a change of E 206 to R in antitrypsin-related peptide dramatically decreased the affinity. The whole binding site of A10 in ETSHR as well as in antitrypsin was larger than the region of similarity. We propose that residues ECHQEEDFV represent the monoclonal antibody A10 epitope. They form an almost continuous sequence of residues 30-37 and 39 in ETSHR. The monoclonal antibody A10 binding site on antitrypsin is shorter. It comprises amino acids 205-208 and 210, from the region of similarity with, probably, additional two residues, H-287 and E 363.

[I/D polymorphism of angiotensin I converting enzyme gene and insulin resistance and some parameters of metabolic syndrome in patients with type 2 diabetes]

Insulinresistance is a component of the metabolic syndrome and important pathogenetic factor of type 2 diabetes mellitus. There are evidences that activation of the renin-angiotensin system (RAS) can decrease insulin sensitivity of tissues. As I/D polymorphism of angiotensin converting enzyme (ACE) gene can influence the activity of RAS, it may also influence insulin resistance. Aim. To assess the relationship between the I/D polymorphism of ACE gene and degree of insulin resistance and intensity of metabolic syndrome in type 2 diabetic patients. Study group and methods. Examined group: 108 type 2 diabetic patients (38 women and 70 men), with mean duration of disease 9.07 +/- 6.68 years, mean age 59.98 +/- 9.10 years. Assessed parameters: body mass index (BMI), waist/hip ratio (WHR), arterial blood pressure. Laboratory tests: concentration of the glycosylated hemoglobin (HbA 1c), glucose, insulin, total cholesterol, HDL and LDL cholesterol, triglycerides, creatinine, uric acid. Insulin resistance was calculated by the HOMA rate. Criterion of insulin resistance was rate > or = 2.5. The diagnosis and assessment of intensity of metabolic syndrome was performed according to criteria of National Education Cholesterol Adult Treatment Program the Panel III. I/D ACE gene polymorphism was evaluated by polymerase chain reaction (PCR). Results. Groups with 11, ID and DD genotype were not different in age, BMI, WHR, duration of diabetes, the prevalence and duration of arterial hypertension, degree of metabolic control and insulinresistance assessed by HOMA rate and intensity of metabolic syndrome. DD genotype carriers had significant higher systolic and diastolic blood pressure (147.8 +/- 19.8 mmHg vs 138.2 +/- 16.5 mmHg, p = 0,02; 89.2 +/- 9.6 mmHg vs 81.7 +/- 8.6, p = 0,003, respectively) than II patients. Conclusion. In type 2 diabetic patients the I/D genotype of ACE gene is not associated with the increased insulin resistance assessed by HOMA rate and intensity of metabolic syndrome.

Studies of phosphodiesterase effects on adipose tissue metabolism in obese subjects by the microdialysis technique

The effect of non-selective (theophylline) inhibition of cyclic AMP breakdown on norepinephrine stimulated lipolysis rate was investigated in subcutaneous adipose tissue of obese subjects. In addition, changes in interstitial glucose and lactate concentration were assessed by means of the microdialysis technique. The interaction of endogenous released insulin and theophylline on adipocyte metabolism was determined. Theophylline and norepinephrine alone increased glycerol outflow significantly. When both agents were perfused in combination, interstitial glycerol concentration increased further. The enhanced glycerol level due to theophylline application was slightly decreased by insulin. In the presence of theophylline, extracellular glucose concentration increased, in contrast to the catecholamine. Norepinephrine decreased interstitial glucose level. When both drugs were added in combination, the level of interstitial glucose increased to about 1 mM, greater than with theophylline alone. With each intervention, lactate was synthesized. Local adipose tissue blood flow was increased by theophylline and theophylline plus norepinephrine. In conclusion, post-receptor mechanisms increased norepinephrine maximal stimulated lipolysis rate in subcutaneous adipose tissue. Glucose uptake was inhibited by the non-specific inhibitor of phosphodiesterase. The effect of insulin on inhibition of lipolysis was modest but sustained in the presence of high theophylline (10(-4) M) concentration. Phosphodiesterase activity may be relatively low in obese subjects in comparison with lean subjects. In lean subjects theophylline caused a transient reversal of the antilipolytic effect of insulin.

[The cysteine bonding in TSH receptor and it function in autoantibodies recognition]

The majority of epitopes for TSH receptor (TSHR) stimulating autoantibodies are clustered around the Nterminal region of the TSH receptor. The characteristic feature of this region is the presence of four cysteine residues. It was proposed that cysteines in positions 29 and 41 in the receptor are connected by disulfide bonds and they are the target for receptor stimulating antibodies. The present study was aimed to check this possibility. The synthetic peptides: peptide corresponding to the part of TSHR containing the above 29-41 cysteine bond, the peptide similar to this peptide but without disulfide bond and the control peptide, containing sequence absent in the receptor were used for rabbit immunization. The thyroid status of all immunized rabbits was the same. Rabbits immunized with peptides related to TSHR generated antisera reactive with TSHR in immunoenzymatic assay. To check specificity of this reaction the influence of the peptides and the antisera on TSH binding to the receptor in competitive assay (TRAK) and their influence on adenylate cyclase activity were studied. It was found that neither synthetic peptides nor antiserum from any rabbit influenced TSH binding to the receptor in TRAK. In contrast low, but significant adenylate cyclase stimulating activity was noticed for antisera from two of six rabbit immunized by peptide containing the disulfide bond. We concluded that such a bond between cysteine residues 29 and 41 are present in TSHR in the site of stimulating antibodies epitope.

[Chemotherapy for colorectal carcinoma in the elderly]

With nearly 50 % of all colorectal cancers being diagnosed in patients at the age of 70 or above colorectal cancer is a disease of the elderly. In an adjuvant setting, fit elderly patients can receive the same benefit from cytotoxic therapy as younger patients with an only slightly increased toxicity. In a palliative setting, the treatment of elderly patients with respect to clinical endpoints such as response, time to progression or overall survival is as effective as in their younger counterparts. In clinical studies, older patients are generally underrepresented and among the elderly patients involved in clinical studies there is a bias towards particularly fit patients. Therefore it is not possible to extrapolate the results of many randomized trials to all elderly patients. A Comprehensive Geriatric Assessment (CGA) should be applied to detect the diversities in the geriatric population. Based on this assessment elderly patients classified as suitable for chemotherapy should be enrolled into clinical trials for colorectal cancer.

Diagnostik und Therapie der akuten Pankreatitis

In acute pancreatitis the evaluation of severity is as important as the diagnosis. If there is evidence for severe pancreatitis, an immediate intensive care of all organ systems is needed, to avoid complications. Besides clinical signs, serum CRP is the most valuable parameter to define severity. According to present knowledge, a CT-scan is only needed in sepsis or multiorgan failure. Non-invasive ventilation should be started early in case of hypoxia. Up to now, no general benefit was detected for antibiotic prophylaxis or enteral nutrition. No consensus exists whether and when endoscopic interventions are superior to surgery in the treatment of infected necrosis.

Genetic screening for glucocorticoid-remediable aldosteronism (GRA): experience of three clinical centres in Poland

Glucocorticoid-remediable aldosteronism (GRA), also known as familial hyperaldosteronism type I (FH-I, OMIM 103900), is a monogenic form of inherited hypertension caused by the presence of a chimaeric gene originating from an unequal cross-over between the CYP11B1 (11beta-hydroxylase) and CYP11B2 (aldosterone synthase) genes. The hybrid gene has the CYP11B1 sequence at the 5' end, including the promoter, and the CYP11B2 sequence at the 3' end. The aim of our study was to evaluate the prevalence of GRA in a Polish population of 129 patients with primary hyperaldosteronism (PHA) and 132 patients with essential hypertension (EH), through the use of a PCR-based test revealing the chimaeric gene. None of our PHA or EH patients was positive for the CYP11B1/CYP11B2 chimaeric gene. These data suggest that GRA is unlikely to be a common cause of hypertension in Polish subjects. However, the real prevalence of GRA in Poland, both in the high-risk group of individuals with primary hyperaldosteronism and in the general population, remains to be established.

[The posttranslational modification of thyrotropin receptor and thyroid diseases]

The thyrotropin receptor (TSHR), lutropin receptor, and follitropin receptor are related members of the superfamily of leucine-rich repeats containing adenylate cyclase stimulating receptors. The unique posttranslational modification of the TSHR leads to the transformation of its monomeric form to the subunit structure where the subunits A and B are connected by disulphide bonds. This natural processing occurs with the release from the receptor of a short peptide C, and is followed by the release of the subunit A. Both monomeric and dimeric forms of the receptor are stimulated by TSH, so no clear functional significance of TSHR modifications have been found. We can speculated that the processing of TSHR with the release of its large fragments contributes to the development of autoimmune diseases and production anti-TSH receptor autoantibodies. The extrathyroidal manifestations of Graves disease may also be related to metastasis of the autoimmune reaction to extrathyroidal sites via the released A subunit. The TSHR processing may, to some extent, be connected to the hyperthyroidism since the release of the subunit A from the receptor augmented the adenylate cyclase activity in the absence of TSH. According to the recent model of receptors action the TSHR is in equilibrium between the inactive (closed) and active (opened) conformations. In opened conformation it can associate with Gs protein and trigger the intracellular signal. TSH and stimulating autoantibodies preferentially bind to opened receptors and stabilizes them.

Effects of moderate consumption of white wine on weight loss in overweight and obese subjects

BACKGROUND

Patients on dietary, weight-reducing treatment commonly are advised against alcohol consumption. In light of the widespread use of alcoholic beverages and the well-established benefits of light to moderate alcohol consumption in risk reduction, a revision of dietary treatment recommendations may be warranted.

OBJECTIVE

To investigate whether daily consumption of moderate amounts of alcohol influences the effectiveness of an energy-restricted diet in overweight and obese subjects.

DESIGN

A prospective randomized clinical trial was conducted, with a 3-months intervention period and two isocaloric dietary regimens containing 6.3 MJ (1500 kcal) each, one with 10% of energy from white wine and one with 10% of energy from grape juice. The trial was performed in obese subjects being recruited from the Obesity Outpatient Clinic at the University Hospital, Ulm, who all habitually consumed moderate amounts of alcohol. Out of 87 patients, 49 were eligible to participate and 40 completed the study (age 48.1+/-11.4 y, BMI 34.2+/-6.4 kg/m(2)). Efficacy parameters were body weight and biomarkers of good health.

RESULTS

All subjects achieved significant body weight reduction. Weight loss in the grape juice group and white wine group was 3.75+/-0.46 and 4.73+/-0.53 kg, respectively. Percent body fat, waist circumference, blood pressure, blood glucose, insulin, triglycerides, and cholesterol were reduced. The antioxidant status was unchanged, as were liver enzyme activities and other safety parameters. There were no significant differences between the groups.

CONCLUSIONS

An energy-restricted diet is effective in overweight and obese subjects used to drinking moderate amounts of alcohol. A diet with 10% of energy derived from white wine is as effective as an isocaloric diet with 10% of energy derived from grape juice.

Residues 34-39 in the thyrotropin receptor are not the target of autoantibodies from sera of patients with Graves' disease

The thyrotropin receptor (TSHR) and alphal-antytripsin contain a fragment of sequence composed of 6 amino acids in which 5 residues are identical. Previously, we have suggested that this region of similarity [residues 34-39: (EEDFRV) in TSHR] is not the target for Graves' disease patients' autoantibodies. To verify this suggestion, we studied the reaction of patients' sera with alphal-antitrypsin. Two methods were used: TRAK assay, normally designed to estimate anti-TSHR autoantibodies in patients' sera, and immunoblotting. A modified version of the former assay was also used to study the influence of the synthetic peptide, corresponding to the region of similarity in TSHR, on Graves' patients sera or on thyrotropin (TSH) binding, and to study the influence of this peptide antiserum on TSH binding to the receptor. The TSHR stimulating and blocking activity of antisera to this peptide was studied in transfected Chinese hamster ovary cells. No influence of alphal-antitrypsin on the binding of patients' antibodies to the receptor were noticed nor were there reactions of autoantibodies with alphal-antitrypsin. We found that patients with anti-TSHR autoantibodies had a normal concentration of alphal-antitrypsin. A peptide corresponding to residues 34-39 did not influence Graves' patients sera and TSH binding and antiserum to this peptide did not influence TSH binding and adenylate cyclase activity. In summary, the results indicated that the sequence EEDFRV is not the target for patients autoantibodies.

Analysis of the therapeutic efficacy of different doses of budesonide in patients with active Crohn's ileocolitis depending on disease activity and localization

BACKGROUND AND AIMS

The nonsystemic steroid budesonide has been used to treat active ileocecal and ileocolonic Crohn's disease (CD). This study investigated the optimal budesonide dose using a pH-dependent release formulation. The goal of treatment was the remission of CD (CDAI <150) within 6 weeks of treatment.

PATIENTS AND METHODS

The study was of randomized, double-blind, dose-finding design. Patients with active CD ileocolitis without steroid pretreatment were treated with 3x2 mg ( n=39), 3x3 mg ( n=33), or 3x6 mg ( n=32) oral pH-modified released budesonide daily.

RESULTS

The remission rates after 6 weeks were 36% with 3x2 mg, 55% with 3x3 mg, and 66% with 3x6 mg. Significantly more patients were in remission while treated with 3x6 mg than with 3x2 mg budesonide/day. Subgroup analyses revealed that patients with high disease activity (CDAI >/= 300) or ileocolonic disease with disease manifestation distal to the transverse colon responded better to the highest budesonide dose.

CONCLUSION

Oral pH-modified released budesonide shows a dose-dependent effectiveness in patients with active ileocolonic CD. In the majority of patients 9 mg budesonide per day is sufficient. However, in patients with highly active disease or ileal disease with distal colonic manifestation higher doses of budesonide could increase the therapeutic response

Prediction of treatment response to rivastigmine in Alzheimer's dementia

OBJECTIVES

To predict the treatment response to rivastigmine in patients with Alzheimer's dementia using neuropsychological and EEG data.

METHODS

A neuropsychological examination and a quantitative EEG study were done in 20 patients with Alzheimer's dementia before initiating treatment with rivastigmine. After one week of treatment a second EEG examination was done. Therapeutic efficacy was determined six months after treatment initiation. Treatment response was defined as improvement in short term memory after six months of rivastigmine treatment.

RESULTS

For the group of patients as a whole, there was a significant improvement in short term memory and orientation during rivastigmine treatment. The mini-mental state score improved from 20.2 to 21.7 (NS). In the EEG, theta power decreased significantly after one week of treatment. Treatment responders had a greater decrease in theta power after one week of treatment and a better short term memory at baseline than non-responders. Decrease in theta power during rivastigmine treatment and baseline short term memory were good predictors of treatment response.

CONCLUSIONS

Generally available neuropsychological and EEG data may be useful for predicting response to rivastigmine in patients with Alzheimer's disease.

Proinflammatory cytokines increase glial fibrillary acidic protein expression in enteric glia

BACKGROUND

Enteric glia protect the integrity of the gut, as loss of enteric glial fibrillary acidic protein (GFAP) positive (+) glia leads to a haemorrhagic jejunoileitis. Crohn's disease (CD) and necrotising enterocolitis (NEC) show pathological changes in enteric glia. Therefore, factors controlling GFAP+ enteric glia are of great interest. The aim of the present study was to characterise enteric glia and determine the effect of interleukin 1beta (IL-1beta), interleukin 4 (IL-4), tumour necrosis factor alpha (TNF-alpha), and lipopolysaccharides (LPS) on cultured enteric glia.

METHODS

Dissected rat colon and cultured enteric glia cells were double labelled with anti-GFAP and anti-S-100 antibodies. For regulatory studies, enteric glia cells were treated with cytokines and LPS. Proliferation was assayed using bromodeoxyuridine (BrdU) and mitosis of enteric glia was blocked by demecolcine.

RESULTS

We were able to distinguish GFAP negative (-) from GFAP+ glia subtypes in situ and in primary cultures. Incubation of cells with IL-1beta, TNF-alpha, and LPS led to a significant increase in GFAP+ enteric glia while IL-4 had no effect on GFAP expression. After incubation with IL-1beta, total intracellular GFAP of enteric glia cells was increased. Upregulation of GFAP+ enteric glia could also be observed after stimulation with IL-1beta on blocking mitosis. BrdU uptake in stimulated enteric glia showed no increased proliferation rate.

CONCLUSIONS

Two different types of enteric glia based on GFAP expression exist in the gut. Proinflammatory cytokines and LPS cause a dramatic increase in GFAP+ enteric glia. This suggests that cytokines play an important role in controlling GFAP+ enteric glia which might in turn be involved in modulating the integrity of the bowel during inflammation.

[Promoter variants of aldosterone synthase gene (CYP11B2) and salt-sensitivity of blood pressure]

The T(-344)C polymorphism in promoter of CYP11B2 gene encoding aldosterone synthase has been associated with differences in plasma aldosterone (ALDO) concentrations. In addition, the results of recent study carried out in Japan suggest that C(-344) allele of CYP11B2 may be a genetic marker of salt-sensitive hypertension characterized by low plasma renin activity (PRA) and high ALDO/PRA ratio. Therefore, it raises the question of whether the T(-344)C polymorphism of CYP11B2 gene may be associated with salt-sensitive hypertension in Caucasians. The DNA samples were obtained from 68 Polish hypertensives. During 3 subsequent 1-week periods each subject received diets of normal, low and high sodium content (120-140, 20-40 and 240-260 mmol Na+/day, respectively). Salt sensitivity was expressed as the difference between mean arterial pressure (MAP) on high salt diet and MAP on low salt one (delta MAPH-L). Genomic DNA isolated from peripheral blood nuclear cells was amplified by PCR method with primers flanking the polymorphic region and C(-344) allele was identified by gain of Hae III restriction site. There were 14 TT homozygotes (20.6%), 35 TC heterozygotes (51.5%) and 19 CC homozygotes (27.9%) in the studied group. No significant differences in delta MAPH-L, glomerular filtration rate, natriuresis, excreted fraction of filtered sodium, PRA, ALDO and ALDO/PRA ratio determined on each diet have been found in subjects according to CYP11B2 genotype. Our preliminary results suggest the lack of association of the T(-344)C CYP11B2 polymorphism with salt-sensitive hypertension as well as with activity of plasma renin-angiotensin-aldosterone system in Caucasian patients.

Fibrogenesis in the pancreas

In recent years, numerous studies have provided novel insights into the pathomechanisms of pancreatic fibrogenesis. This includes in particular the identification and characterization of the pancreatic stellate cells (PSCs) and their role in the synthesis of extracellular matrix (ECM) proteins. It has become clear that pancreatic stellate cell activation is regulated by a complex network of growth factors and cytokines and results in increased expression and release of collagens I and II, fibronectin and other components of ECM. Among the cytokines involved in PSC activation and other fundamental mechanisms of pancreatic fibrosis, transforming growth factor beta (TGFbeta) is of particular relevance. TGFbeta stimulates PSC activation and induces transcription of ECM proteins mainly via activation of the Smad proteins which regulate gene expression through functional interaction with co-operating partner proteins such as the zinc finger transcription factor Sp1. Recent progress in understanding of the biochemical and molecular mechanisms of pancreatic fibrosis, is reviewed here.