Non-inhibition of acetylcholinesterase by cycloSal nucleotides

An acetylcholinesterase (AChE) assay based on the Rappaport method was established to investigate the behaviour of several cycloSal nucleotides against AChE from electrophorus electricus and human sources (purified enzymes). AChE is a physiologically essential enzyme as it catalyzes the hydrolysis of the neurotransmitter acetylcholine. No inhibition was observed in any of the cases.

Novel nucleotide analogues as potential substrates for TMPK, a key enzyme in the metabolism of AZT

Novel cyclic and acyclic analogues of dTMP and AZTMP were synthesized from the corresponding cycloSal-phosphotriesters. This method yielded the nucleotides in good yields with a simple work-up. Investigation of the substrate properties of the modified nucleotides towards TmpK showed, that they are very poor substrates for this key enzyme in the bioactivation of AZT.

Synthesis of oligonucleotide building blocks of 2'-deoxyguanosine bearing a C8-arylamine modification

C8-Arylamine-dG adducts were synthesized by palladium-catalyzed cross-coupling reactions. The corresponding 5'-O-DMTr-3'-O-phosphoramidite-C8-arylamine-dG adducts were synthesized as potential building blocks for the automated synthesis of site-specifically modified oligonucleotides.

Synthesis of carbocyclic analogues of thymidine

A new route towards an enantiomerically pure carbocyclic 2'-deoxyribonucleoside precursor was developed. After coupling with a nucleobase the product is easily accessible for further modifications at the 3'-hydroxy group.

A single nasal allergen challenge increases induced sputum inflammatory markers in non-asthmatic subjects with seasonal allergic rhinitis: correlation with plasma interleukin-5

BACKGROUND

Seasonal allergic rhinitis (SAR) is a risk factor for asthma in affected individuals. Nasal allergic inflammation enhances bone-marrow eosinophil production, mainly via IL-5, and rhinitis patients have increased airway inflammation during the pollen season.

OBJECTIVE

To assess the impact of nasal allergy on sputum inflammatory markers.

METHODS

In an open-labelled, randomized, placebo-controlled cross-over study with 16 non-asthmatic SAR patients (median age 25 years, 56% males), the effect of a single nasal allergen challenge performed out of season on induced sputum inflammatory parameters was evaluated. SAR patients were identified by history, skin-prick test and specific IgE. All patients had normal lung function/bronchial hyper-responsiveness out of season and a negative asthma/wheezing history. Sputum cells and supernatant levels of ECP, sICAM, IL-5 and IL-10, and plasma levels of IL-5 and ECP, were measured before and 24 h after nasal allergen challenge. After a washout period of at least 4 weeks, the procedure was repeated with placebo challenge (diluent).

RESULTS

Nasal allergen challenge led to an increase in sputum ECP (pre = 60 +/- 12, post = 212 +/- 63 micro g/L, P = 0.02 vs. placebo), and sICAM (4.8 +/- 2.7 to 6.5 +/- 2.9 ng/mL, P = 0.02 vs. placebo), whereas IL-10 decreased after provocation (44 +/- 11 to 29 +/- 6 pg/mL, P = 0.06 vs. placebo). Sputum IL-5 was undetectable in all patients. The absolute number of blood and sputum eosinophils did not change significantly after allergen or placebo challenge (P > 0.07, both comparisons). Plasma levels of IL-5 increased after allergen challenge (8.7 +/- 2.9 to 14.5 +/- 3.9 pg/mL, P = 0.001), and the increase in plasma IL-5 was positively correlated with the rise in sputum ECP in a subgroup of 'responders' (n = 12, r = 0.71, P = 0.01).

CONCLUSIONS

A single nasal allergen challenge in SAR patients increased markers of allergic inflammation in the lower respiratory tract, possibly via pronounced activation of inflammatory cells through circulating immediate-type reaction cytokines like IL-5. These findings may provide additional explanatory data for the high susceptibility of SAR patients to incident asthma.

[Left-sided chest pain]

Wir stellen eine 21-jährige aus der Türkei stammende muslimische Patientin mit atypischen links-thorakalen Schmerzen vor. Klinisch und laborchemisch konnte die Diagnose einer Osteomalazie aufgrund mangelnder Sonnenexposition u.a. wegen traditioneller Kleidung gestellt werden. Unter Vitamin-D- und Kalziumsubstitution normalisierten sich sowohl Klinik als auch das Labor. Bei muslimisch gekleideten Frauen mit Knochenschmerzen sollte an eine Osteomalazie gedacht werden. Ob prophylaktisch eine Vitamin-D- und Kalziumsubstitution durchgeführt werden sollte, wird in der Literatur kontrovers diskutiert und kann u.a. von der anamnestisch erhobenen täglichen Kalziumaufnahme der Patientin abhängig gemacht werden.

Fructose breath hydrogen test--is it really a harmless diagnostic procedure?

Usage of hydrogen breath tests has become one of the standard procedures in diagnosing chronic unspecific abdominal pain. These tests are said to be of sufficient specificity and sensitivity, are easily done, non-invasive and are more often practiced in outpatients. A 13-year-old boy is reported with chronic unspecific abdominal pain and growth retardation and so far misdiagnosed hereditary fructose intolerance (HFI), who developed life-threatening adverse effects during the fructose breath hydrogen test. It is concluded that the possibility of HFI should be excluded first by a carefully explored dietary history before the fructose breath test is performed under medical supervision. If there is any suspicion of HFI, a molecular genetic analysis should be preferred.

Combined stimulation of adrenocorticotropin and compound-S by single dose metyrapone test as an outpatient procedure to assess hypothalamic-pituitary-adrenal function

The metyrapone test is used to test the hypothalamic-pituitary-adrenocortical axis. The present study aims to assess the diagnostic accuracy of combined stimulation of ACTH and compound-S (CMP-S). In addition, we analyzed the safety and practicability of this test as an outpatient procedure. A total of 327 metyrapone tests were analyzed retrospectively in 185 patients (mean age, 50.3 +/- 15.2 yr). One hundred thirteen patients had one test, and 72 patients had between 2 and 6 tests over 1-3 yr. Most patients suffered from pituitary adenomas (60 macroadenomas, 63 microadenomas) or other pituitary lesions (n = 29). Metyrapone (2 g) was given at 2400 h as an outpatient procedure. Blood samples for analysis of ACTH, CMP-S, and cortisol were taken at 0730 h. Stimulation of adrenal CMP-S and cortisol by pituitary ACTH demonstrated a dose-response curve with the shape of half a geometric parabola. CMP-S reached a plateau when ACTH rose above 175 ng/liter [r = 0.661, P < 0.0001 for ACTH <175 ng/liter; r = 0.083, P = not significant (NS) for ACTH >175 ng/liter], cortisol flattened at ACTH levels above 230 ng/liter (r = 0.633; P < 0.0001 for ACTH < 230 ng/liter; P = NS for ACTH >230 ng/liter). Alternatively, the sum of CMP-S plus cortisol also flattened when ACTH rose above 230 ng/liter (r = 0.696; P < 0.0001 for ACTH <230; P = NS for ACTH > 230 ng/liter). Receiver operating curve analysis defining a cut-off for ACTH at 150 ng/liter demonstrated a sensitivity of 47% and 67% at a cut-off level for CMP-S at 200 or 260 nmol/liter, respectively. The respective specificity was 82% and 68% for CMP-S. This compared with a sensitivity of 71% and specificity of 69% if the sum of CMP-S plus cortisol of 450 nmol/liter were used as cut-off. The response curve between CMP-S and ACTH implies a maximally stimulated adrenal cortex at circulating ACTH levels above 175 ng/liter. Single measurement of CMP-S using the cut-off at 200 nmol/liter, as suggested in the literature, yields a poor sensitivity of only 47% compared with ACTH. Despite the relatively high cross-reactivity of CMP-S in the cortisol assay, the sum of CMP-S and cortisol levels with a cut-off value of 450 nmol/liter yields a better diagnostic accuracy compared with CMP-S alone.

Basal TSH levels compared with TRH-stimulated TSH levels to diagnose different degrees of TSH suppression: diagnostic and therapeutic impact of assay performance

BACKGROUND

The estimated prevalence of endogenous subclinical hyperthyroidism varies from 4% to 6% and a basal thyroid stimulating hormone (TSH) level < 0.5 mU L-1 may be associated with increased mortality in subjects over 60 years of age who are not on thyroid medication. Exogenous TSH suppression is a mainstay in the treatment of thyroid cancer. Because of recent concerns about potential adverse effects, especially of endogenous TSH suppression on bone, the cardiovascular system and cognitive functions, subclinical hyperthyroidism obtained new clinical importance. We therefore re-evaluated the diagnostic value of basal and thyrotrop in TRH-stimulated serum TSH measurements using TSH assays with different sensitivities.

MATERIALS AND METHODS

A total of 805 oral and nasal TRH stimulation tests were performed on 409 ambulatory subjects with low basal serum TSH concentrations of less than 0.1 mIU L-1. Basal serum TSH was measured either using a second generation assay (functional sensitivity > 0.03 mIU L-1) or two third generation assays (functional sensitivity 0.01 mIU L-1 and 0.007 mU L-1, respectively). Serum TSH concentration was determined before and 3 h after oral administration of 40 mg of TRH and before and 30 min after nasal administration of 2 mg of TRH.

RESULTS

In the oral testing group, the basal TSH levels measured by the different TSH assays were 0.06 +/- 0.03, 0.04 +/- 0.02 and 0.03 +/- 0.02, respectively, whereas the peak TSH levels were 0.4 +/- 0.6, 0.4 +/- 0.6 and 0.3 +/- 0.5 in the patients with subclinical hyperthyroidism. In overt hyperthyroidism, the basal TSH levels were 0.06 +/- 0.02, 0.03 +/- 0.02 and 0.03 +/- 0.02, whereas the peak TSH levels were 0.19 +/- 0.3, 0.16 +/- 0.3 and 0.15 +/- 0.2, respectively. Basal TSH values could discriminate between different degrees of TSH suppression if measured with a third generation assay (P < 0.001), but not with a second generation assay. There was only a weak correlation between basal TSH and peak TSH when measured by a second generation assay (n = 126; r = 0.3; P < 0.001) in contrast to the strong correlation found using the third generation assays (n = 128; r = 0.7; P < 0.001 and n = 69; r = 0.8; P < 0.001, respectively).

CONCLUSIONS

In view of the recent concerns about potential adverse effects in TSH suppression and based on our data, it is mandatory to select a TSH assay with a functional sensitivity of < or = 0.01 mIU L-1 for optimal titration of L-T4 suppressive therapy, especially in patients with thyroid cancer. If, however, only a second generation TSH assay is available, additional TRH testing allows a more careful titration of suppressive thyroxine therapy.

Connexin29 expression, immunocytochemistry and freeze-fracture replica immunogold labelling (FRIL) in sciatic nerve

The recently discovered connexin29 (Cx29) was reported to be present in the central and peripheral nervous systems (CNS and PNS), and its mRNA was found in particular abundance in peripheral nerve. The expression and localization of Cx29 protein in sciatic nerve were investigated using an antibody against Cx29. The antibody recognized Cx29 in HeLa cells transfected with Cx29 cDNA, while nontransfected HeLa cells were devoid of Cx29. Immunoblotting of sciatic nerve homogenate revealed monomeric and possibly higher molecular weight forms of Cx29. These were distinguished from connexin32 (Cx32), which also is expressed in peripheral nerve. Double immunofluorescence labelling for Cx29 and Cx32 revealed only partial colocalization of the two connexins, with codistribution at intermittent, conical-shaped striations along nerve fibers. By freeze-fracture replica immunogold labelling (FRIL), Cx32 was found in gap junctions in the outermost layers of myelin, whereas Cx29-immunogold labelling was found only in the innermost layer of myelin in close association with hexagonally arranged intramembrane particle (IMP) 'rosettes' and gap junction-like clusters of IMPs. Although both Cx32 and Cx29 were detected in myelin of normal mice, only Cx29 was present in Schwann cell membranes in Cx32 knockout mice. The results confirm that Cx29 is a second connexin expressed in Schwann cells of sciatic nerve. In addition, Cx29 is present in distinctive IMP arrays in the inner most layer of myelin, adjacent to internodal axonal plasma membranes, where this connexin may have previously unrecognized functions.

Evidence for a role of the N-terminal domain in subcellular localization of the neuronal connexin36 (Cx36)

The expression and functional properties of connexin36 (Cx36) have been investigated in two neuroblastoma cell lines (Neuro2A, RT4-AC) and primary hippocampal neurons transfected with a Cx36-enhanced green fluorescent protein (EGFP) expression vector. Transfected cells express Cx36-EGFP mRNA, and Cx36-EGFP protein is localized in the perinuclear area and cell membrane. Upon differentiation of cell lines, Cx36-EGFP protein was detectable in processes with both axonal and dendritic characteristics. Small gap junction plaques were found between adjacent cells, and electrophysiological recordings demonstrated that the electrical properties of these gap junctions were virtually indistinguishable from those reported for native Cx36. Mutagenesis of Cx36 led to the identification of a structural element that interferes with normal protein localization. In contrast, site directed mutagenesis of putative protein phosphorylation motifs did not alter subcellular localization. This excludes phosphorylation/dephosphorylation as a major regulatory step in Cx36 protein transport.

Redox centers of 4-hydroxybenzoyl-CoA reductase, a member of the xanthine oxidase family of molybdenum-containing enzymes

4-Hydroxybenzoyl-CoA reductase (4-HBCR) is a key enzyme in the anaerobic metabolism of phenolic compounds. It catalyzes the reductive removal of the hydroxyl group from the aromatic ring yielding benzoyl-CoA and water. The subunit architecture, amino acid sequence, and the cofactor/metal content indicate that it belongs to the xanthine oxidase (XO) family of molybdenum cofactor-containing enzymes. 4-HBCR is an unusual XO family member as it catalyzes the irreversible reduction of a CoA-thioester substrate. A radical mechanism has been proposed for the enzymatic removal of phenolic hydroxyl groups. In this work we studied the spectroscopic and electrochemical properties of 4-HBCR by EPR and Mössbauer spectroscopy and identified the pterin cofactor as molybdopterin mononucleotide. In addition to two different [2Fe-2S] clusters, one FAD and one molybdenum species per monomer, we also identified a [4Fe-4S] cluster/monomer, which is unique among members of the XO family. The reduced [4Fe-4S] cluster interacted magnetically with the Mo(V) species, suggesting that the centers are in close proximity, (<15 A apart). Additionally, reduction of the [4Fe-4S] cluster resulted in a loss of the EPR signals of the [2Fe-2S] clusters probably because of magnetic interactions between the Fe-S clusters as evidenced in power saturation studies. The Mo(V) EPR signals of 4-HBCR were typical for XO family members. Under steady-state conditions of substrate reduction, in the presence of excess dithionite, the [4Fe-4S] clusters were in the fully oxidized state while the [2Fe-2S] clusters remained reduced. The redox potentials of the redox cofactors were determined to be: [2Fe-2S](+1/+2) I, -205 mV; [2Fe-2S] (+1/+2) II, -255 mV; FAD/FADH( small middle dot)/FADH, -250 mV/-470 mV; [4Fe-4S](+1/+2), -465 mV and Mo(VI)/(V)/(VI), -380 mV/-500 mV. A catalytic cycle is proposed that takes into account the common properties of molybdenum cofactor enzymes and the special one-electron chemistry of dehydroxylation of phenolic compounds.

[Experiences with enteral nutrition of patients with cystic fibrosis (CF) via a percutaneous endoscopic gastrostomy (PEG)]

BACKGROUND

We wanted improve the nutritional status of patients with cystic fibrosis with enteral feeding via a percutaneous endoscopic gastrostomy (PEG).

PATIENTS AND METHODS

In a period of 8 years 11 patients underwent a percutaneous endoscopic gastrostomy (PEG), 4 males and 7 females, in the median 14,9 years of age (7,4/20,8). So far we overlook a median duration of enteral feeding therapy of 19,5 months (10/53).

MAIN RESULTS

In 9 of the 11 patients we found a distinct increase of the predicted anthropometrical values,e.g. the weight for height value increased statistically significant in the first 3 months by 10,3 % from 84,7 % to 95,5 % and showed a further increase to 97,8 % after 10 months of nocturnal enteral feeding (p < 0,05). The predicted values of the lung function got stabilized too, with an increase by 9 % of the FEV1 and 3 % of the vital capacity after 10 months. Here was no statistically significance found. In one patient with a poor social-economic background and a lack of compliance the PEG had to be removed surgically because of an abscess formation. Another patient developed an acute gastric ulcer which responded very well onto conservative therapy. In the other patients there were no further complications.

CONCLUSION

We can conclude that in the treatment of patients with cystic fibrosis showing an unsatisfying nutritional status the long-term nocturnal enteral feeding via a PEG is a good and well tolerated method. The best results we achieved when the gastrostomy was placed at an early state of the disease. That's why we demand an early mentioning of this option of enteral feeding to the patients and their families since the involved mostly need a long time for their decision for that invasive procedure.

Transforming growth factor beta (TGFbeta) mediates Schwann cell death in vitro and in vivo: examination of c-Jun activation, interactions with survival signals, and the relationship of TGFbeta-mediated death to Schwann cell differentiation

In some situations, cell death in the nervous system is controlled by an interplay between survival factors and negative survival signals that actively induce apoptosis. The present work indicates that the survival of Schwann cells is regulated by such a dual mechanism involving the negative survival signal transforming growth factor beta (TGFbeta), a family of growth factors that is present in the Schwann cells themselves. We analyze the interactions between this putative autocrine death signal and previously defined paracrine and autocrine survival signals and show that expression of a dominant negative c-Jun inhibits TGFbeta-induced apoptosis. This and other findings pinpoint activation of c-Jun as a key downstream event in TGFbeta-induced Schwann cell death. The ability of TGFbeta to kill Schwann cells, like normal Schwann cell death in vivo, is under a strong developmental regulation, and we show that the decreasing ability of TGFbeta to kill older cells is attributable to a decreasing ability of TGFbeta to phosphorylate c-Jun in more differentiated cells.

Control of specific gene expression by gibberellin and brassinosteroid

We identified a recessive, brassinolide-insensitive mutant caused by a deletion allele (bri1-201) of the brassinosteroid (BR) receptor BRI1. The bri1-201 mutant displayed altered expression levels of genes differentially regulated by gibberellin (GA). RNA-blot analysis revealed that BR and GA antagonistically regulate the accumulation of mRNAs of the GA-responsive GASA1 gene, as well as the GA-repressible GA5 gene. Expression studies with cycloheximide indicated that the antagonistic effects of GA and BR on GA5 require de novo protein synthesis. Reporter transgene analyses and RNA-blot analysis showed that BR and GA modulate GA5 expression, at least in part, at the transcriptional level, and that the signals are independent and subtractive.

TSH-controlled L-thyroxine therapy reduces cholesterol levels and clinical symptoms in subclinical hypothyroidism: a double blind, placebo-controlled trial (Basel Thyroid Study)

This study evaluated the effect of physiological, TSH-guided, L-thyroxine treatment on serum lipids and clinical symptoms in patients with subclinical hypothyroidism. Sixty-six women with proven subclinical hypothyroidism (TSH, 11.7 +/- 0.8 mIU/liter) were randomly assigned to receive L-thyroxine or placebo for 48 wk. Individual L-thyroxine replacement (mean dose, 85.5 +/- 4.3 microg/d) was performed based on blinded TSH monitoring, resulting in euthyroid TSH levels (3.1 +/- 0.3 mIU/liter). Lipid concentrations and clinical scores were measured before and after treatment. Sixty-three of 66 patients completed the study. In the L-thyroxine group (n = 31) total cholesterol and low density lipoprotein cholesterol were significantly reduced [-0.24 mmol/liter, 3.8% (P = 0.015) and -0.33 mmol/liter, 8.2% (P = 0.004), respectively]. Low density lipoprotein cholesterol decrease was more pronounced in patients with TSH levels greater than 12 mIU/liter or elevated low density lipoprotein cholesterol levels at baseline. A significant decrease in apolipoprotein B-100 concentrations was observed (P = 0.037), whereas high density lipoprotein cholesterol, triglycerides, apolipoprotein AI, and lipoprotein(a) levels remained unchanged. Two clinical scores assessing symptoms and signs of hypothyroidism (Billewicz and Zulewski scores) improved significantly (P = 0.02). This is the first double blind study to show that physiological L-thyroxine replacement in patients with subclinical hypothyroidism has a beneficial effect on low density lipoprotein cholesterol levels and clinical symptoms of hypothyroidism. An important risk reduction of cardiovascular mortality of 9-31% can be estimated from the observed improvement in low density lipoprotein cholesterol.

Antiviral activity of cyclosaligenyl prodrugs of acyclovir, carbovir and abacavir

The cyclosaligenyl (cycloSal) derivatives of the monophosphates of three acyclic or carbocyclic guanosine analogues, for example, acyclovir (ACV), carbovir (CBV) and abacavir (ABC), were investigated for their activity against retrovirus (HIV, Moloney sarcoma virus) and herpes simplex virus (HSV) activity in cell culture. The extent of the antiviral potency of the prodrugs depended on the nature of the nucleoside, the substituent on the cycloSal moiety and the virus investigated. Most notably, and unlike the parent compound ACV, cycloSal-ACV monophosphate (MP) prodrugs retained pronounced activity against ACV-resistant (thymidine kinase-deficient) HSV-1 and also gained anti-HIV activity. While the cycloSal-CBVMP prodrugs did not show enhanced activity compared with the parent compound CBV, the cycloSal-ABCMP prodrugs afforded markedly increased potency against both HSV and HIV. Our data indicate that the cycloSal prodrug approach can be useful to deliver directly the MP derivatives of nucleoside analogues into the intact, virus-infected cells, thus improving and extending the antiviral potency and spectrum of the drugs against retro- and herpesvirus strains.

On the symmetry of periodontal disease

BACKGROUND/AIM

Symmetry is a common feature of biological systems, and can be observed in multiple aspects of the human body. The purpose of this study was to estimate the impact of symmetry on variance observed in intraoral topographic distribution patterns of chronic periodontitis.

METHOD

This analysis was performed on a data set from 56 subjects, including clinical and microbiological variables, recorded at the mesial and distal aspect of every tooth in the entire dentition. The impact of contralateral conditions was determined on the level of the site, the tooth, and the quadrant.

RESULTS

Significant correlations were detected between probing depths, recession, attachment levels, total cultivable bacterial counts and the plaque index recorded on the right and left side on all levels of analysis. The odds for bleeding on sampling, as well as for the presence of P. intermedia/nigrescens and A. actinomycetemcomitans increased significantly if the respective contralateral site was positive for the same parameter. In combining ipsilateral and contralateral parameters into the analysis it could be shown in several instances that this contralateral effect was stronger than the impact of other, ipsilateral factors. As an example, the odds for bleeding on sampling increased up to 10 fold if the contralateral site was bleeding, whereas the ipsilateral total cultivable count, determined at the same site, explained less than 30% of the variation in the bleeding tendency.

CONCLUSION

These findings support the view that the development of periodontal disease in any site cannot be explained by the influence of local detrimental factors alone.

Measuring mass transfer processes of octane with the help of an alkSalkB::gfp-tagged Escherichia coli

Diffusion of octane from oily droplets in different microscale settings was measured using Escherichia coli expressing the stable green fluorescent protein (GFP) from the alkB promoter of Pseudomonas oleovorans. GFP fluorescence intensities were determined quantitatively at the single-cell level after 1.0 or 2.5 h incubation and compared with different calibration series using known concentrations of octane. By immobilizing the E. coli sensor cells on the bottom glass plate of a microscope flow chamber, it was possible to monitor the diffusion process for octane in aqueous solution as a function of time and distance from non-aqueous phase droplets of octane alone or oily octane mixtures. When a gas phase was included in the flow chambers, octane transport could be demonstrated from the oily mixtures to the cells through both gas and liquid phase. Assays of non-immobilized sensor cells in microdroplets in the presence or absence of soil particles incubated with octane through the vapour phase revealed a slight reduction in the total amount of induced E. coli cells in the presence of soil. Our results indicate the power of using GFP-marked single-cell biosensors in determining microscale bioavailability of organic pollutants.

Benzyl-functionalized cycloSal-d4T monophosphates

Synthetic routes to benzyl-functionalized cycloSal-d4T monophosphates (7CH2X-cycloSal-d4TMP) have been developed. Their hydrolytic behavior in basic aqueous solution (pH = 7.3) was studied and their hydrolysis half-lives were determined. It turned out that two different degradation pathways are leading to different products: beside the formation of the expected d4TMP and a styrene type derivative, a phenyl-d4T-phosphodiester was obtained as well. The product distribution was specified.

Synthesis, hydrolysis and anti-EBV activity of a series of 3'-modified cycloSal-BVDUMP pronucleotides

A series of cycloSal-BVDUMP phosphate triesters has been prepared. The prototype compound was 3-methyl-cycloSal-BVDUMP 2. Furthermore, a series of 3'-O-acyl-modified derivatives having carboxylic acids with different lipophilicity or a L-configurated alpha-amino acid (phenylalanine) was prepared. The hydrolysis properties in phosphate buffer PBS as well as in PBS containing pig liver esterase (PLE) will be described. Finally, the biological activity against EBV has been determined.

Antimicrobial properties of phenolic compounds from berries

AIMS

To investigate the antimicrobial properties of phenolic compounds present in Finnish berries against probiotic bacteria and other intestinal bacteria, including pathogenic species.

METHODS AND RESULTS

Antimicrobial activity of pure phenolic compounds representing flavonoids and phenolic acids, and eight extracts from common Finnish berries, was measured against selected Gram-positive and Gram-negative bacterial species, including probiotic bacteria and the intestinal pathogen Salmonella. Antimicrobial activity was screened by an agar diffusion method and bacterial growth was measured in liquid culture as a more accurate assay. Myricetin inhibited the growth of all lactic acid bacteria derived from the human gastrointestinal tract flora but it did not affect the Salmonella strain. In general, berry extracts inhibited the growth of Gram-negative but not Gram-positive bacteria. These variations may reflect differences in cell surface structures between Gram-negative and Gram-positive bacteria. Cloudberry, raspberry and strawberry extracts were strong inhibitors of Salmonella. Sea buckthorn berry and blackcurrant showed the least activity against Gram-negative bacteria.

CONCLUSION

Different bacterial species exhibit different sensitivities towards phenolics.

SIGNIFICANCE AND IMPACT OF THE STUDY

These properties can be utilized in functional food development and in food preservative purposes.

Finding similar cases within a hospital information system

Most of the theoretical medical knowledge comes from literature. The knowledge obtained from the vast majority of patients is then lost. The vast majority of patients do not participate in the elaboration of medical knowledge, apart from the lucky few entering a clinical trial or a published case study. Moreover, locally treated patients do not always correspond to the same time, space or age context as literature patients. How can the knowledge of one patient be used for treating other patients? How can we save the knowledge of our own patients? Hospital information systems contain a lot of detailed and precise information about many patients over several years. Databases containing detailed information can provide solutions based on case analysis (Case-based reasoning or "similar case approach"). An example of a Geneva's decision system called Archimed is shown here.

Gibberellin response mutants identified by luciferase imaging

The gibberellin (GA) 20-oxidase encoded by Arabidopsis GA5 catalyzes the synthesis of active GAs. GA5 is a regulatory step in GA biosynthesis as GA5 mRNA levels are negatively regulated by its bioactive GA products. A fusion between the GA5 promoter and the firefly luciferase reporter (GA5-LUC) was shown to be similarly regulated, indicating GA feedback of GA5 occurs at the transcriptional level. The fidelity of the GA5-LUC reporter permitted a fusion genetic screen to identify mutants altered in transgene expression. This bioimaging screen identified two types of recessive mutants with increased LUC activity and apparent GA-related growth phenotypes, a dwarf (lue1) and two late flowering mutants (fpa1-3 and fpa1-4). Mutant progeny exhibited altered levels of LUC and of endogenous GA5 and other GA-regulated mRNAs. SSLP-based mapping localized lue1 to chromosome I near the ga2 locus, although complementation analyzes showed that lue1 is not allelic to ga2. Mapping and complementation analyzes showed that the late flowering mutants are allelic to fpa1. This provides genetic evidence for crosstalk between the autonomous and gibberellin-dependent flowering pathways.

[Ogilvie syndrome with cecal perforation. A rare complication after isolated thoracic trauma. Case report and current literature review]

In reviewing 750 cases of acute colonic pseudo-obstruction from the literature, the most commonly associated disorders are listed and the therapeutical management is critically discussed. The authors describe an additional case of a 77-year-old male with ogilvie's syndrome following isolated thoracic trauma. Ogilvie's syndrome has been used synonymously with acute colonic pseudo-obstruction (ACPO) of the colon, first defined by Sir Heneage Ogilvie in 1948. If inappropriately managed, the massive colonic dilatation may lead to caecal ischaemia and perforation with a high mortality rate. Aetiology and pathogenesis of the syndrome are still unknown, but mostly ACPO is associated with a wide variety of medical conditions. Often it appears to be a complication after abdominal or pelvic surgery or trauma. In few cases the pseudo-obstruction is isolated and therefore truly idiopathic. Conservative treatment is indicated if the caecum is less than 12 cm in diameter. If there is a progressive increase in diameter or no improvement is seen, the colon should be decompressed without further delay. The indications for surgery are failure of conservative treatment and colonoscopy, signs for ceacal ischaemia or perforation. The choice of procedure, coecostomy or resection, is dictated by the state of the caecum. Due to a high mortality rate (up to 50%) if the caecum is perforated, an aggressive therapeutical management should be applied.

Cyclosaligenyl-2',3'-didehydro-2',3'-dideoxythymidine monophosphate: efficient intracellular delivery of d4TMP

Cyclosaligenyl-2',3'-didehydro-2', 3'-dideoxythymidine-5'-monophosphate (cycloSal-d4TMP) is a potent and selective inhibitor of human immunodeficiency virus replication in cell culture and differs from other nucleotide prodrug approaches in that it is designed to selectively deliver the nucleotide 5'-monophosphate by a controlled, chemically induced hydrolysis. Its antiviral efficacy in cell culture is at least as good as, if not superior to, that of d4T. CycloSal-d4TMP was found to lead to the efficient intracellular release of d4TMP in a variety of cell lines, including both wild-type CEM and thymidine kinase-deficient CEM/TK(-) cells. Under similar experimental conditions, exposure of CEM/TK(-) cells to d4T failed to result in significant d4TTP levels. The intracellular conversion of cycloSal-d4TMP proved to be both time and dose dependent. The half-life of d4TTP generated intracellularly from d4T- or cycloSal-d4TMP-treated CEM cells was approximately 3.5 h, and the intracellular ratios of d4TTP/d4TMP in cells exposed to cycloSal-d4TMP gradually increased from 1 to 3.4 upon prolonged incubation. Radiolabeled cycloSal-d4TMP could be separated as its two R(p) and S(p) diastereomers on high-performance liquid chromatography. The R(p) diastereomer of cycloSal-d4TMP was 3- to 7-fold more efficient in releasing d4TMP and generating d4TTP than the S(p) cycloSal-d4TMP diastereomer. This correlated well with the 5-fold more pronounced antiviral activity of the R(p) diastereomer versus the S(p) diastereomer. d4TMP is a poor substrate for the cytosolic 5'(3')-deoxyribonucleotidase (V(max)/K(m) for d4TMP: 0.08 of V(max)/K(m) for dTMP) and is only slowly hydrolyzed to d4T. This contributes to the efficient conversion of the prodrug of d4TTP.

[Amiodarone-induced thyrotoxicosis]

Amiodarone is the most important drug in the treatment of ventricular arrhythmias and is widely used for atrial fibrillation. Thyrotoxicosis, a classical side effect, was thought to be iodine induced, but recent evidence suggests that other mechanisms play an important role (toxic effect on thyreocytes, immunological effects). Thyrotoxicosis due to amiodarone is difficult to treat and is further complicated by the pro-arrhythmic potential of thyrotoxicosis and the fading antiarrhythmic effect after amiodarone withdrawal. The mechanism, diagnosis and therapy of amiodarone-induced thyrotoxicosis are discussed in the light of the available literature.

EPR and Mössbauer studies of benzoyl-CoA reductase

Benzoyl-CoA reductase catalyzes the two-electron transfer from a reduced ferredoxin to the aromatic ring of benzoyl-CoA; this reaction is coupled to stoichiometrical ATP hydrolysis. A very low reduction potential (less than -1 V) is required for the first electron transfer to the aromatic ring. In this work the nature of the redox centers of purified benzoyl-CoA reductase from Thauera aromatica was studied by EPR and Mössbauer spectroscopy. The results obtained indicated the presence of three [4Fe-4S] clusters. Redox titration studies revealed that the reduction potentials of all three clusters were below -500 mV. The previously reported S = 7/2 state of the enzyme during benzoyl-CoA-independent ATPase activity (Boll, M., Albracht, S. J. P., and Fuchs, G. (1997) Eur. J. Biochem. 244, 840-851) was confirmed by Mössbauer spectroscopy. Inactivation by oxygen was associated with the irreversible conversion of part of the [4Fe-4S] clusters to [3Fe-4S] clusters. Acetylene stimulated the benzoyl-CoA-independent ATPase activity and induced novel EPR signals with g(av) >2. The presence of simple cubane clusters in benzoyl-CoA reductase as the sole redox-active metal centers demonstrates novel aspects of [4Fe-4S] clusters since they adopt the role of elemental sodium or lithium which are used as electron donors in the analogous chemical Birch reduction of aromatic rings.

[Laparoscopic fundoplication for gastroesophageal reflux: experience with 49 surgical patients (1994-1999)]

INTRODUCTION

Chronic gastrooesophageal reflux disease (GERD) is the most common benign pathology of the upper gastrointestinal tract in the western world. We report our experience of laparoscopic antireflux surgery.

PATIENTS AND METHODS

49 patients underwent laparoscopic antireflux surgery at our clinic between 1994 and 1999. 48 patients were followed up in a retrospective study. Mean follow-up was 30 months (2-66). 31 patients (64.6%) were male and 17 female (35.4%). Mean age was 48 years (26-74). The surgical method was tailored to the case: total Nissen fundoplication (87.5%) was indicated after ruling out oesophageal motility disorders by manometry. In 6 patients (12.5%) with coexisting dysphagia or pathological manometry, partial posterior fundoplication (Toupet) was performed.

RESULTS

Mean operating time of 215 minutes (125-420) for the first 10 Nissens was significantly reduced to 119 minutes (70-190) for the last 10 procedures with increasing experience of the surgeon. No severe intraoperative complications occurred and mortality was 0%. Conversion rate was 4.2%. Mean hospital stay was 6.1 days (1-36). At follow-up 93.7% were free of reflux symptoms without medication, and only one patient (2.1%) suffered from regular reflux which had to be treated with PPI daily. 2 patients (4.2%) took PPI only occasionally. Persistent dysphagia occurred in 7 patients (14.8%). 5 (10.5%) underwent one or more endoscopic dilatations, after which 3 patients (6.3%) reported an improvement of dysphagia. No patient needed reoperation on due to mechanical complications. 1 patient (2.1%) developed a paraoesophageal hernia 4.5 years after a Nissen procedure. According to the Visick Score, 95.8% of all patients were satisfied with their outcome (Visick I/II).

CONCLUSIONS

With careful investigation and indication, laparoscopic antireflux surgery is a safe and effective alternative method to long-term medication with PPI in the treatment of gastrooesophageal reflux disease. Morbidity is low. Persistent postoperative dysphagia can be reduced with either a short and floppy total fundoplication or a partial wrap.

Interactions of conformationally biased north and south 2'-fluoro-2', 3'-dideoxynucleoside 5'-triphosphates with the active site of HIV-1 reverse transcriptase

Molecular dynamics simulations of a ternary complex of HIV-1 reverse transcriptase (RT), double-stranded DNA, and bound dideoxynucleoside-5'-triphosphate (RT-DNA-ddNTP), utilizing the ddNTPs ddATP, betaFddATP, and alphaFddATP, explain the experimentally observed order of potency of these 5'-triphosphates as inhibitors of RT: ddATP > betaFddATP > alphaFddATP. On the basis of RT's known preference to bind the incoming dNTP (or ddNTP) with a north conformation at the polymerase site, alphaFddATP, which in solution prefers almost exclusively a north conformation, was predicted to be the most potent inhibitor. However, Tyr115, which appears to function as a steric gate to preclude the binding of ribonucleoside 5'-triphosphates, prevents the effective binding of alphaFddATP in its preferred north conformation. The south-biased betaFddATP, while able to bind to RT without hindrance by Tyr115, has to pay a high energy penalty to be flipped to the active north conformation at the polymerase site. Finally, the more flexible and less conformationally biased ddATP is able to switch to a north conformation at the RT site with a smaller energy penalty than betaFddATP. These results highlight the opposite conformational preferences of HIV-1 RT for alphaFddATP and betaFddATP and help establish conformational guidelines for optimal binding at the polymerase site of this enzyme.

Glycoprotein-associated amino acid exchangers: broadening the range of transport specificity

Members of the newly discovered glycoprotein-associated amino acid transporter family (gpaAT-family) share a similar primary structure with >40% identity, a predicted 12-transmembrane segment topology and the requirement for association with a glycoprotein (heavy chain) for functional surface expression. Five of the six identified gpaATs (light chains) associate with the surface antigen 4F2 heavy chain (4F2hc = CD98), a ubiquitous plasma membrane protein induced in cell proliferation, and which is also highly expressed at the basolateral surface of amino acid transporting epithelia. The differing tissue localizations of the 4F2hc-associated gpaATs appear to complement each other. As yet, a single gpaAT (b(0,+)AT) has been shown to associate with rBAT, a 4F2hc-related glycoprotein mainly localized in intestine and kidney luminal brush-border membranes. The transport characteristics of gpaATs have been shown, by expression in heterologous systems, to correspond to the previously described transport systems L, y+L, xc- and b(o,+). These (obligatory) exchangers of broad substrate specificity (with the exception of xCT) are expected to equilibrate the concentrations of their substrate amino acids across membranes. Thus, the driving force provided by a transmembrane gradient of one substrate amino acid, such as that generated by a parallel functioning unidirectional transporter, can be used by a gpaAT to fuel the secondary active vectorial transport of other exchangeable species. Vectorial transport of specific amino acids is also promoted by the intrinsic asymmetry of these exchangers. The fact that genetic defects of the epithelial gpaATs b(0,+)AT and y+LAT1 cause non-type I cystinuria and lysinuric protein intolerance, respectively, demonstrates that these gpaATs perform vectorial secondary and/or tertiary active transport of specific amino acids in vivo.

Fusion genetic analysis of gibberellin signaling mutants

A fusion genetic strategy was used to identify gibberellin (GA) signaling mutants in transgenic Arabidopsis expressing the beta-glucuronidase (GUS) and firefly luciferase (LUC) reporter genes under control of the GA-responsive GASA1 promoter. Initial analyses determined the spatial and temporal patterns of reporter expression, and showed that reporter induction by GA was antagonized by ABA. gamma-Irradiated M2 progeny with altered reporter activities were identified by LUC bioimaging followed by GUS assays and northern hybridization of the endogenous GASA1 mRNA. Genetic analysis showed that three mutants, which overexpressed both reporters and endogenous GASA1, were caused by recessive (goe1 and goe2, for GASA over-expressed) and semi-dominant (goe3) mutations at different loci. These mutants are altered in their sensitivity to GA and the GA biosynthetic inhibitor paclobutrazol, and in the expression of several GA signaling related genes.

The activating component of the anaerobic ribonucleotide reductase from Escherichia coli. An iron-sulfur center with only three cysteines

Class III anaerobic ribonucleotide reductase small component, named protein beta, contains a (4Fe-4S) center. Its function is to mediate electron transfer from reduced flavodoxin to S-adenosylmethionine, required for the introduction of a glycyl radical in the large component, named protein alpha, which then becomes active for the reduction of ribonucleotides. By site-directed mutagenesis we demonstrate that the three cysteines of the conserved CXXXCXXC sequence are involved in iron chelation. Such a sequence is also present in the activase of the pyruvate formate-lyase and in the biotin synthase, both carrying an iron-sulfur center involved in reductive activation of S-adenosylmethionine. Even though they are able to bind iron in the (4Fe-4S) form, as shown by Mössbauer spectroscopy, the corresponding Cys to Ala mutants are catalytically inactive. Mutation of the two other cysteines of the protein did not result in inactivation. We thus conclude that the (4Fe-4S) cluster has, in the wild type protein, only three cysteine ligands and a fourth still unidentified ligand.

Self-rated health, life satisfaction and personal characteristics of post-menopausal women under estrogen replacement therapy

OBJECTIVES

To describe the prevalence of oestrogen replacement therapy (ERT)-use among post-menopausal women in relation with personal and socio-economic characteristics and to examine the association of ERT-use with self-rated health and selected aspects of life satisfaction.

METHODS

Population survey data were derived from a cohort study of 511 Bernese women, aged 55-65 years. Data were collected by means of telephone interviews. Overall prevalence of ERT-use, and selected associations with personal and socio-economic characteristics were investigated using descriptive statistical methods and logistic regression. The relations of ERT-use with five self-reported health measures were explored using Spearman's correlation coefficients. The associations of ERT-use with six dichotomous variables on satisfaction with various aspects of life were tested with chi-square tests in cross tabulations.

RESULTS

The overall prevalence of self reported ERT-use was 17.6%. ERT was more prevalent women younger than 61 years than in women in the older age group. Women with a body mass index (BMI) under 25 reported ERT-use significantly more frequently than women with higher BMI (OR=3.16, CI 1.87-5.34). ERT-use was more prevalent in women with relatively high education: OR=2.01, CI 1.18-4.00. The self-reported health measures and the satisfaction items were not significantly associated with ERT-use.

CONCLUSIONS

ERT-use among post-menopausal women was found to be associated with higher educational level and lower BMI. ERT-users did not report better health or life-satisfaction.

Hypervolumetric hemodilution with HES 100/0.5 10% in patients with peripheral arterial occlusive disease (Fontaine, stage II): an open clinical and pharmacological phase IV study

The efficacy of three weekly interventions with hypervolumetric hemodilution of a new preparation of hydroxyethyl starch (HES 100/0.5, 10%, C2/C6 substitution ratio of 6.5) on pain-free walking distance of patients with peripheral arterial occlusive disease (PAOD) stage IIb on the Fontaine classification was investigated. In addition quantitative data on the pharmacokinetic properties of this HES preparation, and it's impact on hemorheology, hemostasis and homeostasis were shown. Ten patients were included according to a predefined protocol, and treated openly with 500 ml HES 100/0.5 10% on nine occasions over 18 days. Pain-free walking distance, the main outcome measure, showed a mean increase of 82 m (+60%). Hematocrit decreased 4 percentage points on average (5.5 percentage points one hour after interventions). Plasma viscosity dropped 5% on average with significant changes immediately after interventions only in patients whose baseline values had been equal to or above the 2 s reference area. Erythrocyte aggregation decreased by 16% in the course of treatment (8% immediately after interventions), systolic blood pressure by 13%, and total protein by 7%. Complement showed a trend towards lower values (-20%), and creatinine, pH and urine viscosity remained unchanged. Apart from complement changes, all reductions mirrored the dilution effects. As to pharmacokinetics, serum mean molecular weight distribution was very similar to that of the infusion. A minor adverse drug reaction (light, spontaneously disappearing pruritus) was observed in one case.

Inhibitory effect of cycloSaligenyl-nucleoside monophosphates (cycloSal-NMP) of acyclic nucleoside analogues on HSV-1 and EBV

The in vitro antiviral activity of a new series of cycloSal-pro-nucleotides derived from the acyclic nucleoside analogues aciclovir and penciclovir against herpes simplex virus type 1 (HSV-1), thymidine kinase deficient (TK-) HSV-1, and Epstein-Barr virus (EBV) was evaluated. Using the XTT-based tetrazolium reduction assay EZ4U, the cycloSal derivatives were examined for their antiviral and cytotoxic effects in HSV-1 as well as HSV-1-TK--infected Vero cells. The anti-EBV activity was assessed by means of an EBV DNA hybridization assay using a digoxigenin-labeled probe specific for the Bam H1-W-fragment of the EBV genome and by measuring viral capsid antigen (VCA) expression in P3HR-1 cells by indirect immunofluorescence. Among the new cycloSal-phosphotriesters the three aciclovir monophosphates proved to be potent and selective inhibitors of HSV-1 replication, EBV DNA synthesis and EB-VCA expression. Of interest is the retention of activity of the aciclovir monophosphates in HSV-1-TK--infected cells. Particularly 3-methyl-cycloSal-aciclovir monophosphate retained the same effectiveness, as compared to the wild type virus strain. In contrast to the aciclovir pro-nucleotides the penciclovir cycloSal-phosphotriesters exhibited at best only a marginal antiviral effect on HSV and EBV replication.

LAT2, a new basolateral 4F2hc/CD98-associated amino acid transporter of kidney and intestine

Glycoprotein-associated amino acid transporters (gpaAT) are permease-related proteins that require heterodimerization to express their function. So far, four vertebrate gpaATs have been shown to associate with 4F2hc/CD98 for functional expression, whereas one gpaAT specifically associates with rBAT. In this study, we characterized a novel gpaAT, LAT2, for which mouse and human cDNAs were identified by expressed sequence tag data base searches. The encoded ortholog proteins are 531 and 535 amino acids long and 92% identical. They share 52 and 48% residues with the gpaATs LAT1 and y(+)LAT1, respectively. When mouse LAT2 and human 4F2hc cRNAs were co-injected into Xenopus oocytes, disulfide-linked heterodimers were formed, and an L-type amino acid uptake was induced, which differed slightly from that produced by LAT1-4F2hc: the apparent affinity for L-phenylalanine was higher, and L-alanine was transported at physiological concentrations. In the presence of an external amino acid substrate, LAT2-4F2hc also mediated amino acid efflux. LAT2 mRNA is expressed mainly in kidney and intestine, whereas LAT1 mRNA is expressed widely. Immunofluorescence experiments showed colocalization of 4F2hc and LAT2 at the basolateral membrane of kidney proximal tubules and small intestine epithelia. In conclusion, LAT2 forms with LAT1 a subfamily of L-type gpaATs. We propose that LAT1 is involved in cellular amino acid uptake, whereas LAT2 plays a role in epithelial amino acid (re)absorption.