Biomedical subjects

M Suter

Publications and source records attributed to M Suter.

At least 55 records · Page 3Linked to original sources

PubMed2000

Adenosine 5'-phosphosulfate sulfotransferase and adenosine 5'-phosphosulfate reductase are identical enzymes.

Adenosine 5'-phosphosulfate (APS) sulfotransferase and APS reductase have been described as key enzymes of assimilatory sulfate reduction of plants catalyzing the reduction of APS to bound and free sulfite, respectively. APS sulfotransferase was purified to homogeneity from Lemna minor and compared with APS reductase previously obtained by functional complementation of a mutant strain of Escherichia coli with an Arabidopsis thaliana cDNA library. APS sulfotransferase was a homodimer with a monomer M(r) of 43,000. Its amino acid sequence was 73% identical with APS reductase. APS sulfotransferase purified from Lemna as well as the recombinant enzyme were yellow proteins, indicating the presence of a cofactor. Like recombinant APS reductase, recombinant APS sulfotransferase used APS (K(m) = 6.5 microM) and not adenosine 3'-phosphate 5'-phosphosulfate as sulfonyl donor. The V(max) of recombinant Lemna APS sulfotransferase (40 micromol min(-1) mg protein(-1)) was about 10 times higher than the previously published V(max) of APS reductase. The product of APS sulfotransferase from APS and GSH was almost exclusively SO(3)(2-). Bound sulfite in the form of S-sulfoglutathione was only appreciably formed when oxidized glutathione was added to the incubation mixture. Because SO(3)(2-) was the first reaction product of APS sulfotransferase, this enzyme should be renamed APS reductase.

Amino Acid Sequence↗

PubMed2000

The effects of an oral multivitamin combination with calcium, magnesium, and zinc on psychological well-being in healthy young male volunteers: a double-blind placebo-controlled trial.

RATIONALE: Vitamin and mineral supplements may be associated with improved psychological status. OBJECTIVE: The present study tested the effects of a multivitamin and mineral supplement (Berocca) on psychological well-being. METHODS: In a double-blind randomised-control trial, 80 healthy male volunteers were assigned to either Berocca or placebo. Questionnaires measuring psychological state were completed and a blood sample taken to determine plasma zinc concentration on day 1 (pre-treatment) and again on day 28 (post-treatment), following 28 days of treatments, which were administered at a dosage of one tablet daily. At the end of the study, the acceptability of the treatment and participants' awareness of treatment condition were assessed, as was habitual dietary behaviour. RESULTS: Relative to placebo, treatment with Berocca was associated with consistent and statistically significant reductions in anxiety and perceived stress. Participants in the Berocca group also tended to rate themselves as less tired and better able to concentrate following treatment. In addition, participants registered more somatic symptoms following placebo than following Berocca. These effects cannot be attributed to differences in the acceptability of the two treatments or to participants guessing what treatment they received. CONCLUSION: These findings demonstrate that Berocca significantly reduces anxiety and perceived stress.

Adolescent↗

PubMed2000

Inhibition of glutathione synthesis reduces chilling tolerance in maize.

The role of glutathione (GSH) in protecting plants from chilling injury was analyzed in seedlings of a chilling-tolerant maize (Zea mays L.) genotype using buthionine sulfoximine (BSO), a specific inhibitor of gamma-glutamylcysteine (gammaEC) synthetase, the first enzyme of GSH synthesis. At 25 degrees C, 1 mM BSO significantly increased cysteine and reduced GSH content and GSH reductase (GR: EC 1.6.4.2) activity, but interestingly affected neither fresh weight nor dry weight nor relative injury. Application of BSO up to 1 mM during chilling at 5 degrees C reduced the fresh and dry weights of shoots and roots and increased relative injury from 10 to almost 40%. Buthionine sulfoximine also induced a decrease in GR activity of 90 and 40% in roots and shoots, respectively. Addition of GSH or gammaEC together with BSO to the nutrient solution protected the seedlings from the BSO effect by increasing the levels of GSH and GR activity in roots and shoots. During chilling, the level of abscisic acid increased both in controls and BSO-treated seedlings and decreased after chilling in roots and shoots of the controls and in the roots of BSO-treated seedlings, but increased in their shoots. Taken together, our results show that BSO did not reduce chilling tolerance of the maize genotype analyzed by inhibiting abscisic acid accumulation but by establishing a low level of GSH, which also induced a decrease in GR activity.

Adaptation, Physiological↗

PubMed2000

Laparoscopic management of mechanical small bowel obstruction: are there predictors of success or failure?

BACKGROUND: Laparoscopy is used increasingly for the management of acute abdominal conditions. For many years, previous abdominal surgery and intestinal obstruction have been regarded as contraindications to laparoscopy because there is an increased risk of iatrogenic bowel perforation. The role of laparoscopy in acute small bowel obstruction remains unclear. METHODS: Since 1995, data from patients undergoing laparoscopic surgery have been entered prospectively into a database. Patients who underwent surgery before 1995 were added retrospectively to the same database. The charts of all patients treated surgically for mechanical small bowel obstruction were reviewed. Univariate analysis was performed to identify factors associated with success or failure, especially intraoperative complications, conversion, and postoperative morbidity. Stepwise logistic regression was used to assess for independent variables. RESULTS: This study included 83 patients (56 women and 27 men) with a mean age of 56 years (range, 17-91 years). Conversion was necessary in 36 cases (43%). Laparoscopy alone was successful in 47 patients (57%). Intraoperative complications were noted in 16% and postoperative complications in 31% of the patients. Eight reoperations (9%) were necessary. Mortality was 2.4%. Duration of surgery (p < 0.001) and a bowel diameter exceeding 4 cm (p = 0. 02) were predictors of conversion. No risk factor for intraoperative complication was identified. Accidental bowel perforation (p = 0. 008) and the need for conversion (p = 0.009) were the only independent factors associated with an increased risk of postoperative complications. CONCLUSIONS: Laparoscopic management of small bowel obstruction is possible in roughly 60% of the patients selected for this approach. Morbidity is lower, resumption of a normal diet is faster, and hospital stay is shorter than with patients requiring conversion. No clear predictor of success or failure was identified, but intraoperative complications must be avoided. If the surgeon is widely experienced in advanced laparoscopic surgery and there is a liberal conversion policy, laparoscopy is a valuable alternative to conventional surgery in the management of acute small bowel obstruction.

Acute Disease↗

PubMed2000

A 3-year experience with laparoscopic gastric banding for obesity.

BACKGROUND: The introduction of laparoscopic techniques-especially that of gastric banding-and the fact that conservative management does not provide satisfactory long-term results in patients with morbid obesity has resulted in a marked increase in the demand for bariatric surgery in our department since 1995. In this paper, we present our experience during the first 3 years with this approach. METHODS: Data for all patients who had bariatric surgery at our institution were collected prospectively. They were analyzed for the purpose of this study. RESULTS: A total of 150 patients were operated on between December 1995 and December 1998 (37 months). There were 130 women and 20 men, with a mean age of 37.5 years (range, 19-62). The mean initial excess body weight was 102.9% (range, 58-191%), and the mean initial body mass index (BMI) was 44. 6 kg/m(2) (range, 35.1-64.1). A Lapband was used in 101 cases and a SAGB in 47 cases. In two patients in whom conversion was necessary, we performed a vertical banded gastroplasty. Duration of surgery decreased over time from 210 min (first 20 cases) to 73 min (last 20 cases). Six patients (4%) developed major complications, one of whom died. The median duration of postoperative hospital stay was 3 days. The mean follow-up was 17 months. In all, 24 patients (16%) developed late complications, and 22 (14.6%) required reoperation, mainly for band slippage and/or pouch dilatation (14 cases). An incorrect surgical technique used for the first 30 patients (Lapband within the lesser sac) was responsible for more than half of these complications. The mean excess weight loss was 34% at 6 months, 55% at 1 year, and 56% at 2 years. Compared to vertical banded gastroplasty (197 cases between 1981 and 1995), postoperative morbidity was greatly decreased, late morbidity was similar, and weight loss was equivalent. CONCLUSIONS: Laparoscopic gastric banding is followed by a weight reduction that is similar to that observed after vertical banded gastroplasty, with a much lower postoperative morbidity, a shorter hospital stay, and an earlier resumption of normal activities. If these results can be confirmed by long-term follow-up, laparoscopic gastric banding will be confirmed as the restrictive procedure of choice for morbid obesity.

Adult↗

PubMed2000

Accelerator mass spectrometry as a powerful tool for the determination of 129I in rainwater

129I is a very long-lived radionuclide (T(1/2) = 15.7 x 10(6) years) that is present in the environment both because of natural and anthropogenic sources. Its environmental interest, for example, as a tracer of geological processes, makes it the research target of a growing scientific community. However, its detection in environmental samples by radiometric methods is very difficult because of its long half-life. In this work, we present the methodology developed for its detection by Accelerator Mass Spectrometry (AMS) in rainwater.

Journal Article↗

PubMed2000

Sulfate assimilation in higher plants characterization of a stable intermediate in the adenosine 5'-phosphosulfate reductase reaction.

The enzyme catalysing the reduction of adenosine 5'-phosphosulfate (AdoPS) to sulfite in higher plants, AdoPS reductase, is considered to be the key enzyme of assimilatory sulfate reduction. In order to address its reaction mechanism, the APR2 isoform of this enzyme from Arabidopsis thaliana was overexpressed in Escherichia coli and purified to homogeneity. Incubation of the enzyme with [35S]AdoPS at 4 degrees C resulted in radioactive labelling of the protein. Analysis of APR2 tryptic peptides revealed 35SO2-3 bound to Cys248, the only Cys conserved between AdoPS and prokaryotic phosphoadenosine 5'-phosphosulfate reductases. Consistent with this result, radioactivity could be released from the protein by incubation with thiols, inorganic sulfide and sulfite. The intermediate remained stable, however, after incubation with sulfate, oxidized glutathione or AdoPS. Because truncated APR2, missing the thioredoxin-like C-terminal part, could be labelled even at 37 degrees C, and because this intermediate was more stable than the complete protein, we conclude that the thioredoxin-like domain was required to release the bound SO2-3 from the intermediate. Taken together, these results demonstrate for the first time the binding of 35SO2-3 from [35S]AdoPS to AdoPS reductase and its subsequent release, and thus contribute to our understanding of the molecular mechanism of AdoPS reduction in plants.

Adenosine Phosphosulfate↗

PubMed2000

Investigations into the Genetic Variation, Population Structure, and Breeding Systems of the Fern Asplenium trichomanes subsp. quadrivalens.

The genetic structure of five populations of the tetraploid fern Asplenium trichomanes subsp. quadrivalens in northern Switzerland was analyzed. Asplenium trichomanes subsp. quadrivalens is one of the most common and most widespread ferns in Europe. In this study we have combined genetic investigations, spatial autocorrelation, and breeding experiments to investigate in detail five populations from natural rock faces. Enzyme electrophoresis revealed very low genetic variability within and among the populations. The small amount of variation was partitioned mainly among the localities, indicated by high Fst values up to 0.764. Overall means of the proportion of polymorphic loci (P=0.076), the mean number of alleles per locus (A=1.086), and the mean expected heterozygosity (H=0.018) were low compared with other ferns (e.g., Kirkpatrick et al. 1990). Very few heterozygous individuals were found. Values of the fixation index (F) were high, ranging between 0.732 and 1.000 and indicating substantial inbreeding. Spatial autocorrelation showed different patterns of substructure in populations of A. trichomanes subsp. quadrivalens with a tendency for patches in short distances (up to 1.5 m). The breeding experiments with isolated prothalli and prothalli pairs showed that a mean of 56.4% of the isolated prothalli were successful in sporophyte formation. The highest rate in one population was 83.3%. We conclude that genetic load must be low in A. trichomanes subsp. quadrivalens. Sporophyte formation was statistically more successful in the experiments with gametophyte pairs than in isolates, indicating that additional cross-fertilization occurred. The latter agreed with the occurrence of few heterozygote samples and the small number of multilocus phenotypes found in natural habitats. Asplenium trichomanes subsp. quadrivalens is shown to be a highly inbreeding taxon with the capability of single spore colonization and subsequent founding of new populations. Such features can be hypothesized to have contributed to the postglacial colonization and the widespread distribution of this taxon in Europe.

Journal Article↗

PubMed2000

Leaf age-dependent differences in sulphur assimilation and allocation in poplar (Populus tremula x P. alba) leaves.

35S-sulphate was flap-fed to poplar leaves of different leaf development stages - young developing, expanding, mature, and old mature poplar leaves. (35)S-sulphate was taken up independent of the leaf development stage. Whereas young development leaves did not export the (35)S taken up, export increased with increasing leaf development stage. Expanding leaves allocated the exported (35)S mainly into apical tree parts (73-87%) and only to a minor extent (13-27%) in basipetal direction. Neither lower trunk sections nor the roots were sinks for the exported (35)S. Expanding and developing leaves, but not the shoot apex, were the main sinks for the (35)S allocated in apical direction. In contrast, mature and old mature leaves exported the (35)S taken up mainly in basipetal direction (65-82%) with the roots constituting the main sinks. The (35)S allocated into apical tree parts was found in expanding and developing leaves, but only to a minor extent in the shoot apex. Apical allocated (35)S was identified as sulphate. Apparently the demand of young developing leaves for reduced sulphur was not fulfilled by mature leaves. Therefore, reduced sulphur for growth and development of young developing leaves must be supplied from other sources. In vitro activity of enzymes involved in assimilatory sulphate reduction was measured to investigate whether demand for reduced sulphur by young leaves is met by their own sulphate reduction. ATP sulphurylase and APS reductase activities were not significantly lower in developing than in mature leaves. Sulphite reductase and serine acetyltransferase activities were highest in developing leaves; O:-acetylserine (thiol) lyase activity was similar in all leaf developing stages. Apparently, young developing poplar leaves are able to produce their own reduced sulphur for growth and development. Whether other sources such as storage tissues and/or roots are involved in reduced sulphur supply to developing leaves remains to be elucidated.

Biological Transport↗

PubMed2000

Regulation of sulfate assimilation by nitrogen in Arabidopsis.

Using Arabidopsis, we analyzed the effect of omission of a nitrogen source and of the addition of different nitrogen-containing compounds on the extractable activity and the enzyme and mRNA accumulation of adenosine 5'-phosphosulfate reductase (APR). During 72 h without a nitrogen source, the APR activity decreased to 70% and 50% of controls in leaves and roots, respectively, while cysteine (Cys) and glutathione contents were not affected. Northern and western analysis revealed that the decrease of APR activity was correlated with decreased mRNA and enzyme levels. The reduced APR activity in roots could be fully restored within 24 h by the addition of 4 mM each of NO(3)(-), NH(4)(+), or glutamine (Gln), or 1 mM O-acetylserine (OAS). (35)SO(4)(2-) feeding showed that after addition of NH(4)(+), Gln, or OAS to nitrogen-starved plants, incorporation of (35)S into proteins significantly increased in roots; however, glutathione and Cys labeling was higher only with Gln and OAS or with OAS alone, respectively. OAS strongly increased mRNA levels of all three APR isoforms in roots and also those of sulfite reductase, Cys synthase, and serine acetyltransferase. Our data demonstrate that sulfate reduction is regulated by nitrogen nutrition at the transcriptional level and that OAS plays a major role in this regulation.

Arabidopsis↗

PubMed2000

Palmoplantar hyperkeratosis in Irish terriers: evidence of autosomal recessive inheritance.

An abnormal development of the epidermis of the footpad was observed in Irish terriers. At the age of six months, the affected animals developed smooth parchment-like footpads. The pad epidermis then hardened and grew lateral cone-like protrusions of up to 5 mm in diameter. Fissures and cracks developed and these predisposed the animal to secondary infection. The repeated occurrence in subsequent generations led to the assumption of a hereditary form of hyperkeratosis. Evidence for an autosomal recessive mode of inheritance was derived from a retrospective analysis of the breeder's records. The clinical, histopathological and ultrastructural features of the disease are presented and the genetic transmission and its implications discussed.

Animals↗

PubMed2000

Chemokine gene expression in astrocytes of Borna disease virus-infected rats and mice in the absence of inflammation.

Borna disease virus (BDV) causes CD8(+) T-cell-mediated meningoencephalitis in immunocompetent mice and rats, thus providing a valuable animal model for studying the mechanisms of virus-induced central nervous system (CNS) immunopathology. Chemokine-mediated leukocyte recruitment to the CNS is a crucial step in the development of neurological disease. We found increased mRNA levels of IP-10 and other chemokines in brains of adult rats following infection with BDV. The marked increase in chemokine gene expression at about day 8 postinfection seemed to immediately precede the inflammatory process. In brains of rats infected as newborns, in which inflammation was only mild and transient, sustained expression of IP-10 and RANTES genes was observed. In situ hybridization studies revealed that astrocytes were the major source of IP-10 mRNAs in brains of rats infected as newborns and as adults. In brains of infected mice lacking CD8(+) T cells (beta2m(0/0)), transcripts encoding IP-10 and RANTES were also observed. IP-10 transcripts were also present in a small number of scattered astrocytes of infected knockout mice lacking mature B and T cells as well as functional alpha/beta and gamma interferon receptors, indicating that BDV can induce chemokine synthesis in the absence of interferons and other B- or T-cell-derived cytokines. These data provide strong evidence that CNS-resident cells are involved in the early localized host immune response to infection with BDV and support the concept that chemokines are pivotal for the initiation of virus-induced CNS inflammation.

Animals↗

PubMed2000

Anti- and pro-oxidative properties of PADMA 28, a Tibetan herbal formulation.

There is growing public interest in traditional medicine. PADMA 28, a multicompound herbal preparation derived from Tibetan medicine, has proven efficacy in some clinical trials and tests at the cellular level. We report here on studies of PADMA 28 at the molecular level. Extracts of PADMA 28 contain both reducing and metal ion-chelating substances. In this way, PADMA 28 acts as a powerful antioxidant or prooxidant, depending on its concentration and the reaction under study.

Antioxidants↗

PubMed2000

Vertical banded gastroplasty: long-term results comparing three different techniques.

BACKGROUND: Vertical banded gastroplasty (VBG) has been our procedure of choice for the treatment of morbid obesity from 1981-1995, at which time it was replaced by laparoscopic gastric banding. Three different techniques have been used for banding: silastic band, marlex mesh, adjustable sphincter. The purpose of this paper is to present the long-term results. METHODS: The charts from all patients operated on during the aforementioned period were reviewed and the data analysed retrospectively. RESULTS: This series comprises 197 patients, 172 females and 25 males, with a mean initial excess weight of 94.8% (6-300%) and a mean initial Body Mass Index (BMI) of 42.9 kg/m2 (23-88 kg/m2). 73 patients had a silastic band, 40 Marlex mesh, and 84 an adjustable sphincter. Overall excess weight loss was 66% after 12-24 months, and remained between 50 and 60% up to 9 years postoperatively. There was no difference between the 3 groups. 82 patients (41%) developed a total of 117 complications during follow-up. Among them were stenosis 20%, staple-line disruption 11%, incisional hernia 13%, severe esophagitis 7% and band migration 1.5%. Stenosis developed more often with a silastic band or an adjustable sphincter, and severe esophagitis was more prevalent after the adjustable sphincter. 58 patients required one or more procedures for correction, including dilatation in 21, band removal in 17, band replacement in 15, restapling in 19 and incisional hernia repair in 11 patients. Overall, 29.4% of patients had to be reoperated. There were more reoperations in the silastic and adjustable sphincter groups compared with the Marlex mesh group. CONCLUSIONS: VBG is associated with a rapid weight loss that is relatively well-maintained over time, although there is a tendency to slight weight regain after 2 years. The price for these results is high if complications and further necessary procedures are considered, especially after banding with a silastic band or an adjustable sphincter. Marlex mesh represents the banding material of choice if VBG is chosen.

Adult↗

PubMed2000

Value of laparoscopic staging for Hodgkin disease.

Because of the potential for complications with laparotomy and splenectomy, and the widespread use of combination chemotherapy as first-line treatment, surgical staging is now performed in only 30% of patients with Hodgkin disease. Laparoscopic staging has rarely been reported. Three patients with the nodular sclerosis cell type of Hodgkin disease underwent laparoscopic staging. Mean operative time was 207 minutes. No conversion to laparotomy was necessary. There were no peri- or postoperative complications and no deaths. Mean blood loss was negligible. The pathologist deemed all liver and lymph nodes biopsies adequate for histologic analysis. Stage IA and IIA were confirmed in two patients: one patient with stage IIA was upstaged to IIIA after surgery. Performed by an experienced team, laparoscopy is the procedure of choice for abdominal staging of patients with Hodgkin disease.

Adult↗

PubMed1999

Control of early viral and bacterial distribution and disease by natural antibodies.

Natural antibodies are often dismissed from immunological analysis as "background," but they may play an important role in conferring immunity against infections. In antibody-free mice infected with various viruses or with Listeria monocytogenes, viral or bacterial titers in peripheral organs, including the kidney and brain, were 10 to 100 times greater than in antibody-competent mice (and enhanced their susceptibility to some infections), and titers in secondary lymphoid organs were 10 to 100 times lower than in antibody-competent mice. Thus, natural antibodies play a crucial role by preventing pathogen dissemination to vital organs and by improving immunogenicity through enhanced antigen-trapping in secondary lymphoid organs.

Animals↗

PubMed1999

BAC-VAC, a novel generation of (DNA) vaccines: A bacterial artificial chromosome (BAC) containing a replication-competent, packaging-defective virus genome induces protective immunity against herpes simplex virus 1.

This study aimed to exploit bacterial artificial chromosomes (BAC) as large antigen-capacity DNA vaccines (BAC-VAC) against complex pathogens, such as herpes simplex virus 1 (HSV-1). The 152-kbp HSV-1 genome recently has been cloned as an F-plasmid-based BAC in Escherichia coli (fHSV), which can efficiently produce infectious virus progeny upon transfection into mammalian cells. A safe modification of fHSV, fHSVDeltapac, does not give rise to progeny virus because the signals necessary to package DNA into virions have been excluded. However, in mammalian cells fHSVDeltapac DNA can still replicate, express the HSV-1 genes, cause cytotoxic effects, and produce virus-like particles. Because these functions mimic the lytic cycle of the HSV-1 infection, fHSVDeltapac was expected to stimulate the immune system as efficiently as a modified live virus vaccine. To test this hypothesis, mice were immunized with fHSVDeltapac DNA applied intradermally by gold-particle bombardment, and the immune responses were compared with those induced by infection with disabled infectious single cycle HSV-1. Immunization with either fHSVDeltapac or disabled infectious single cycle HSV-1 induced the priming of HSV-1-specific cytotoxic T cells and the production of virus-specific antibodies and conferred protection against intracerebral injection of wild-type HSV-1 at a dose of 200 LD(50). Protection probably was cell-mediated, as transfer of serum from immunized mice did not protect naive animals. We conclude that BAC-VACs per se, or in combination with genetic elements that support replicative amplification of the DNA in the cell nucleus, represent a useful new generation of DNA-based vaccination strategies for many viral and nonviral antigens.

Animals↗

PubMed1999

Fragmented mitochondrial DNA is the predominant carrier of oxidized DNA bases.

Previous analyses indicated a high level of oxidative base modification in mitochondrial DNA, the extent of which raised questions about the methodological validity and biological implications. In the present study DNA was isolated from rat liver mitochondria under carefully controlled conditions, and the extent of base oxidation, DNA fragmentation, and nuclear DNA contamination were analyzed. DNA isolated from intact mitochondria treated with DNase consisted of 16.3 kilobase pairs, mostly circular, mitochondrial DNA molecules and a mixture of nuclear and mitochondrial DNA fragments, as identified by agarose gel electrophoresis and hybridization. High-performance liquid chromatography in combination with electrochemical detection confirmed that the overall level of 8-hydroxy-2'-deoxyguanosine, a marker commonly used in the analysis of base oxidation, is higher in mitochondrial than in nuclear DNA. Importantly, 8-hydroxy-2'-deoxyguanosine is relatively scarce in the 16.3 kilobase pair mitochondrial DNA molecules (0.051 pmol/microgram) but is present in high levels in mitochondrial DNA fragments (0.741 pmol/microgram). The fragments constitute about 18% of total mitochondrial DNA. The antitumor agent bleomycin, which binds to DNA, forms an iron complex capable of transferring electrons from Fe2+ to molecular oxygen. Exposure of mitochondria to bleomycin and iron resulted in nicking but not in a significant increase in base oxidation of 16.3 kilobase pair mitochondrial DNA, whereas the amount and the oxidation level of fragmented mitochondrial DNA significantly increased. These findings are relevant for a better understanding of the role of mitochondria in aging and various diseases and are consistent with the notion that despite the overall high DNA oxidation level, mitochondria can faithfully proliferate.

8-Hydroxy-2'-Deoxyguanosine↗