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J Widmer

Publications and source records attributed to J Widmer.

At least 19 recordsLinked to original sources

Magnesium involvement in sleep: genetic and nutritional models.

Alterations of peripheral magnesium (Mg) concentration have been reported in association with several behavioral disorders and sleep organization. Blood Mg regulation is under a strong genetic control, whereas brain Mg regulation does not seem to be affected. We have studied peripheral and central levels of Mg and analyzed sleep in two lines of mice selected for low (MGL) and high (MGH) red blood cell (RBC) Mg levels. The same variables were also studied in C57BL/6J mice before and after 3 weeks of Mg deficiency. Whereas blood Mg was highly affected by the selection, brain Mg exhibited only small differences between the two lines. In contrast, Mg deficiency strongly decreased both central and peripheral Mg levels. Sleep analysis indicated that in both models the amount of paradoxical sleep was lower in mice with higher Mg levels. The amplitude of daily variation in sleep and slow-wave sleep delta power was markedly decreased in MGH line. Quantitative electroencephalogram (EEG) analysis also revealed a faster theta peak frequency in MGH mice, irrespective of behavioral states. Central Mg showed significant correlations with the amount of paradoxical sleep and sleep consolidation. However, because the direction of these correlations was not consistent, it is concluded that optimal, (physiological) rather than high or low, Mg levels are needed for normal sleep regulation.

Animals↗

Blood and brain magnesium in inbred mice and their correlation with sleep quality.

A strong genetic component in the regulation of blood magnesium (Mg) levels has been demonstrated. The regulation and distribution of brain Mg levels, however, have never been assessed. Herein we report on the genetic variation of peripheral and central Mg levels in six inbred strains of mice. In addition, the possible involvement of Mg in sleep regulation was assessed by establishing correlations between Mg and sleep parameters obtained before and after a 6-h sleep deprivation. Although genotype strongly determined blood Mg levels, it did not affect brain Mg, suggesting that central and peripheral Mg are regulated differently. Central Mg displayed a highly structure-specific distribution with frontal cortex having the highest and brain stem the lowest values. Whereas for the amount and distribution of baseline sleep only marginal correlations with Mg were found, Mg contents in four of nine brain structures were highly positively correlated with the length of slow-wave sleep episodes during recovery. This relationship suggests that higher levels of Mg in specific brain sites promote sleep quality as part of a recovery process.

Animals↗

Are preventive HIV interventions at airports effective?

BACKGROUND: Few empirical data exist on the impact of preventive human immunodeficiency virus (HIV) interventions on intended and actual sexual behavior of international tourists. The present cross-sectional study is based on a 2 3 2 design. METHODS: The sample consisted of departing and arriving passengers (n = 3100) at Zurich Airport with destinations in countries where heterosexual HIV transmission is dominant. While 41% of the tourists obtained information about safer sex, the remaining 59% without such intervention served as control group. Departing passengers completed a short questionnaire focusing on their planned sexual behavior. Arriving passengers were asked about their actual behavior during the journey. Subjects of the intervention group also evaluated the impact of the consultation. RESULTS: Most travelers appreciated the intervention and reported that they received important information. Members of the intervention group were better informed than those of the control group about the risk of heterosexually transmitted HIV infection (p <.01). They also indicated more often that they could imagine having casual sex abroad (23% vs 16%, p <.01). However, the two groups did not differ with regard to planned condom use or actual sexual behavior. Whereas most of departing passengers indicated that they would use condoms consistently, only half of the passengers who reported casual sex actually did so. Subjects who refused to participate in the intervention tended to consider it as irrelevant and reported less consistent condom use. CONCLUSIONS: Although travel health interventions focusing on casual sex are appreciated and increase the knowledge, they failed to result in significant behavior modification. Future projects should attempt to approach possible risk groups more specifically and to have more impact.

Adult↗

Weak association between blood sodium, potassium, and calcium and intensity of symptoms in major depressed patients.

In previous reports, we showed that plasma and erythrocyte magnesium were increased in many drug-free hospitalized depressed patients. Furthermore, we observed that erythrocyte magnesium content was related to the intensity of the symptoms. Highly depressed patients had the highest magnesium values. Today, we report the results of plasma and erythrocyte sodium and potassium, and of total and ultrafilterable plasma calcium in 66 hospitalized patients with major depression compared to 58 healthy controls. No consistent differences in these biochemical parameters are observed between patients when separated according to intensity of anxiety, psychomotor retardation, and moral distress. Plasma sodium is higher and plasma potassium lower in female patients of all subgroups as compared to controls. Both male patients and controls have erythrocyte sodium and potassium levels that are significantly different from those of females. This clearly suggests a separation into genders in such studies. In conclusion--in contrast to blood magnesium--sodium, potassium, and calcium levels do not seem to be related to the intensity of the main clinical symptoms in hospitalized patients with major depression.

Adult↗

Regulation of 5'-AMP-activated protein kinase activity by the noncatalytic beta and gamma subunits.

The mammalian 5'-AMP-activated protein kinase is a heterotrimer consisting of an alpha catalytic subunit and beta and gamma noncatalytic subunits, each of which is represented in a larger isoprotein family, related to the SNF1 kinase and its interacting proteins in yeast. In this study, we have used mammalian cell transfection to compare the activities of the two alpha subunit isoforms, alpha-1 and alpha-2, and to study the influence of the noncatalytic subunits on enzyme subunit association and activity. Expression of epitope-tagged protein subunits in COS7 cells indicates detectable but low level kinase activity for each of the two catalytic alpha subunits. Co-expression of alpha subunits with the beta or gamma subunits modestly increases kinase activity accompanied by the formation of alpha/beta or alpha/gamma heterodimers. Co-expression of all three subunits, however, is accompanied by a 50-110-fold increase in kinase activity with the formation of a heterotrimeric complex. In addition to binding of each noncatalytic subunit to the alpha subunit, the beta and gamma subunits bind to each other, likely resulting in a more stable heterotrimeric complex. The increase in kinase activity associated with expression of this heterotrimer is due both to an increase in enzyme-specific activity (units/enzyme mass) and to an apparent enhanced alpha subunit expression. Co-expression of a catalytically defective alpha subunit or the beta/gamma-binding COOH-terminal domain of the alpha subunit results in reduced heterotrimeric kinase activity. The synergistic positive regulatory roles for both the noncatalytic beta and gamma subunits of 5'-AMP-activated protein kinase contrasts with the Snf1p kinase, where only heterodimers of Snf1p and Snf4p seem to be required for maximum kinase activity.

AMP-Activated Protein Kinases↗

Identification of a second human acetyl-CoA carboxylase gene.

Acetyl-CoA carboxylase (ACC), an important enzyme in fatty acid biosynthesis and a regulator of fatty acid oxidation, is present in at least two isoenzymic forms in rat and human tissues. Previous work has established the existence of a 265,000 Da enzyme in both the rat and human (RACC265; HACC265) and a higher-molecular-mass species (275,000-280,000 Da) in the same species (RACC280; HACC275). An HACC265 gene has previously been localized to chromosome 17. In the present study, we report cloning of a partial-length human cDNA sequence which appears to correspond to HACC275 and its rat homologue, RACC280, as judged by mRNA tissue distribution and cell-specific regulation of mRNA/protein expression. The gene encoding this isoenzymic form of ACC has been localized to the long arm of human chromosome 12. Thus, ACC is represented in a multigene family in both rodents and humans. The newly discovered human gene and its rat homologue appear to be under different regulatory control to the HACC265 gene, as judged by tissue-specific expression in vivo and by independent modulation in cultured cells in vitro.

Acetyl-CoA Carboxylase↗

Non-catalytic beta- and gamma-subunit isoforms of the 5'-AMP-activated protein kinase.

The mammalian 5'-AMP-activated protein kinase (AMPK) is a heterotrimeric protein consisting of alpha-, beta-, and gamma-subunits. The alpha-subunit is the catalytic subunit and is related to the yeast Snf1p kinase. In this study, we report the cloning of full-length cDNAs for the non-catalytic beta- and gamma-subunits. The rat liver AMPK beta-subunit clone predicts a protein of 30,464 Da, which is related to the Sip1p, Sip2p, and Gal83p subfamily of yeast proteins that interact with Snf1p and are involved in glucose regulation of gene expression. The AMPK beta-subunit, when expressed in bacteria and in mammalian cells, migrates anomalously on SDS gels at an apparent molecular mass of 40 kDa. Rat and human liver AMPK gamma-subunit clones predict a protein of 37,577 Da (AMPK-gamma1), which is related to the yeast Snf4p protein that copurifies with Snf1p and to a larger family of other human AMPK gamma-isoforms. The mRNAs for both AMPK- beta and AMPK-gamma1 are widely expressed in rat tissues, consistent with a broad role for AMPK in cellular regulation. These data reveal a mammalian multisubunit protein kinase strikingly similar to the multisubunit glucose-sensing Snf1 kinase complex. The identification of isoform families for the AMPK subunits indicates the potential diversity of the roles of this highly conserved signaling system in nutrient regulation and utilization in mammalian cells.

AMP-Activated Protein Kinases↗

Mammalian AMP-activated protein kinase subfamily.

The mammalian 5'-AMP-activated protein kinase (AMPK) is related to a growing family of protein kinases in yeast and plants that are regulated by nutritional stress. We find the most prominent expressed form of the hepatic AMPK catalytic subunit (alpha 1) is distinct from the previously cloned kinase subunit (alpha 2). The alpha 1 (548 residues) and alpha 2 (552 residues) isoforms have 90% amino acid sequence identity within the catalytic core but only 61% identity elsewhere. The tissue distribution of the AMPK activity most closely parallels the low abundance 6-kilobase alpha 1 mRNA distribution and the alpha 1 immunoreactivity rather than alpha 2, with substantial amounts in kidney, liver, lung, heart, and brain. Both alpha 1 and alpha 2 isoforms are stimulated by AMP and contain noncatalytic beta and gamma subunits. The liver alpha 1 isoform accounts for approximately 94% of the enzyme activity measured using the SAMS peptide substrate. The tissue distribution of the alpha 2 immunoreactivity parallels the alpha 2 8.5-kilobase mRNA and is most prominent in skeletal muscle, heart, and liver. Isoforms of the beta and gamma subunits present in the human genome sequence reveal that the AMPK consists of a family of isoenzymes.

Amino Acid Sequence↗

Relationship between erythrocyte magnesium, plasma electrolytes and cortisol, and intensity of symptoms in major depressed patients.

53 male and female drug-free major depressed patients were separated into three groups according to the severity of the depression. In the entire regrouped population, plasma and erythrocyte magnesium (Mg) were shown to increase as compared with 48 healthy controls, confirming our previous studies. The middle and highly depressed patients had higher erythrocyte and also plasma Mg levels than either lowly depressed patients or controls. Only, a few differences were noticed in plasma sodium, potassium and calcium (Ca) in the three groups of patients, except for ultrafiltrable plasma Ca, measured for the first time in affective disorders. Thus, erythrocyte and also plasma Mg are shown to be associated with the intensity of the depression. As blood hypomagnaesemia is often related to hyperexcitability, further investigations are actually in process to shown whether hypermagnesaemia might be, in contrast, associated with psychomotor retardation as observed in many depressed patients.

Adult↗

Catalytic subunits of the porcine and rat 5'-AMP-activated protein kinase are members of the SNF1 protein kinase family.

The 5'-AMP-activated protein kinase (AMPK) regulates the fatty acid and sterol synthesizing pathways via phosphorylation of acetyl-CoA carboxylase and HMG-CoA reductase, respectively. Highly purified kinase from porcine liver contains three apparent subunits of molecular mass 63 kDa, 40 kDa and 38 kDa. Peptide sequencing of the 63 kDa protein (AMPK63cat) revealed that this polypeptide is the catalytic subunit of the kinase. Porcine peptide sequences were used to clone by RT-PCR partial length cDNAs for the catalytic domains of the porcine AMPK63cat, and its rat homolog, which were virtually identical in deduced amino acid sequence. Screening of a rat liver cDNA library with these partial length cDNAs and with degenerate oligonucleotides yielded several unique clones, some of which had a 142 bp deletion in the catalytic domain of the kinase. A consensus full-length sequence with a 1.7 kb open reading frame has been constructed from overlapping library and PCR-derived clones. A large mRNA for rat AMPK63cat (8.5 kb) is expressed in nearly all rat tissues, with highest levels detectable in heart and skeletal muscle. Using PCR, the presence of two mRNA species with or without the 142 bp deletion in the catalytic domain was noted in all rat tissues examined. Comparison of the deduced protein sequence of AMPK63cat reveals highly conserved homologies in both the catalytic and non-catalytic domains to several members of the SNF1 kinase family, including kinases from Arabidopsis, barley, rye, and S. cerevesiae, as well as to other mammalian kinases and to a C. elegans kinase. The high evolutionary conservation of both kinase structure and function (metabolite sensing) coupled with their pattern of tissue/organism expression suggest that the mammalian members of this kinase family likely play wider roles than the regulation of cellular lipid metabolism.

AMP-Activated Protein Kinases↗

Sodium-magnesium exchange in erythrocyte membranes from patients with affective disorders.

The Vmax of erythrocyte sodium-magnesium exchange was measured for the first time in 63 patients suffering from affective disorders and compared to that in 33 healthy subjects. Depressed patients had a significantly higher Vmax (215 +/- 13 vs. 151 +/- 14 mumol/l.cells/h; p < 0.005; mean +/- SEM). This tendency was conserved after division of the 63 patients into three clinical subgroups according to the DSM-III-R criteria. Thirty-four patients from this panel were divided into three subgroups according to the chemical class of the antidepressant drug used and were followed up during a 3-month period of drug treatment. Mood improvement over the 3-month period was associated with a slow increase in Vmax of Na/Mg exchange (delta increase approximately 25 mumol/l.cells/h), except in the subgroup of patients treated with non-tricyclic antidepressants (n = 8). These results are consistent with the previously reported link between high erythrocyte magnesium content and affective disorders. Indeed, enhanced Na/Mg exchange Vmax, which probably results from an increased number of transport units per cell, contributes to the normalization of red blood cell magnesium content correlated with mood improvement.

Adolescent↗

The registration function as a critical dependency in a lifetime clinical record (LCR).

Over the past two years, we have successfully migrated the Regenstrief Clinical Information System into our hospital. Integral to this process was the need to develop interfaces and processes supporting movements of patient identification data between the existing clinical management system (Unity, SMS) and Carebase (RCIS). Critical to the implementation of Carebase was the development of an interface between Carebase and the registration system based upon a unique medical record number. Even more critical was the development of stable processes that supported the accurate patient identification and assignment of medical record numbers. The medical record number at our institution is assigned or verified at the time of registration. Major problems occurred when patients presented during system down-times and existing medical record numbers could not be accessed, resulting in multiple registrations and medical record numbers for the same patient. This resulted in data fragmentation and required merging at a later date. Other more serious problems resulted from the assignment of the same medical record number to separate patients and with the mixing of data from multiple patients into one patient record. This was largely due to the failure of clerical personnel to appropriately identify patients at the time of registration, or multiple patients sharing identification documents, a common problem in our geographic area. Given that clinical data was to be maintained and added to the repository for several decades, errors such as these in registration would prove catastrophic. The interfaces between the various clinical systems that pass data to Carebase are all HL-standard and largely prevent data passage if registration data is inaccurate. During the early stages of implementation, approximately 300 exceptions per day were generated from clinical systems attempting to pass data to the repository. Following re¿engineering of the registration process, education of clerical personnel, and analysis of exception type, the number of exceptions due to faulty registration data fell to less than one per week. To achieve improvement in exception volume, several innovative measures were undertaken. Firstly, down-time procedures were changed to require query of the LCR for existing registration data. The LCR was maintained on a separate platform that experienced essentially no down-time and was available for this purpose. This largely eliminated the need for the use of "down-time numbers" or medical record numbers that could be temporarily assigned to patients registered when the registration system was unavailable (data would subsequently be merged into existing patient records if the patient was found to be currently in the system). If the patient was not in the LCR, then a permanent number was assigned in sequence. A registration dataset was developed and encoded onto a magnetic card (Carecard, Eltrax) and carried by patients. This enabled the rapid verification of registration data on subsequent visits to the parent institution or affiliated clinical sites. The issue of fraudulent use of the card and encoded registration dataset, however, remained problematic. Currently, a new imaging system is being installed that will soon enable the inclusion of a photograph of the patient as a component of the registration dataset. Perhaps the most significant change in the registration process involved the education of central registration and admitting personnel. An educational program was developed that reinforced the need for accuracy in collecting registration data, identifying patients, and assigning medical record numbers; more importantly, it stressed the linkage of the registration function and patient care. Lastly, an aggressive approach to monitoring exceptions resulting from errors in registration was developed. A near real-time process for identifying errors in registrations allowed for rapid intervention and feedback to involved de

Medical Records Systems, Computerized↗

Mammalian 5'-AMP-activated protein kinase non-catalytic subunits are homologs of proteins that interact with yeast Snf1 protein kinase.

The 5'-AMP-activated protein kinase is responsible for the regulation of fatty acid synthesis by phosphorylation and inactivation of acetyl-CoA carboxylase. The porcine liver 5'-AMP-activated protein kinase 63-kDa catalytic subunit co-purifies 14,000-fold with a 38- and 40-kDa protein (Mitchelhill, K.I. et al. (1994) J. Biol. Chem. 269, 2361-2364). The 63-kDa subunit is homologous to the Saccharomyces cerevisiae Snf1 protein kinase, which regulates gene expression during glucose derepression. Peptide amino acid and polymerase chain reaction-derived partial cDNA sequences of both the pig and rat liver enzymes show that the 38-kDa protein is homologous to Snf4p (CAT3) and that the 40-kDa protein is homologous to the Sip1p/Spm/GAL83 family of Snf1p interacting proteins. Sucrose density gradient and cross-linking experiments with purified 5'-AMP-activated protein kinase suggest that both the 38- and 40-kDa proteins associate tightly with the 63-kDa catalytic polypeptide in either a heterotrimeric complex or in dimeric complexes. The 40-kDa subunit is autophosphorylated within the 63-kDa subunit complex. The sequence relationships between the mammalian 5'-AMP-activated protein kinase and yeast Snf1p extend to the subunit proteins consistent with conservation of the functional roles of these polypeptides in cellular regulation by this family of metabolite-sensing protein kinases.

AMP-Activated Protein Kinases↗

Identification of human acetyl-CoA carboxylase isozymes in tissue and in breast cancer cells.

1. In the rat, acetyl-CoA carboxylase (ACC), a rate-limiting enzyme in fatty acid metabolism, exists as at least two different isozymes (M(r) 265,000 and 280,000) that display distinct tissue-specific distribution and regulation. 2. Based on the study of human tissue and human-derived breast cancer cell lines by enzyme isolation and protein blotting techniques, we have now identified two human isoforms of M(r) 265,000 (HACC 265) and 275,000 (HACC 275), each of which is homologous to one of the rat isozymes. 3. Human breast carcinoma cell lines show variable expression of these two isoforms, mirrored in the estimation of ACC acetyl-CoA kinetics.

Acetyl-CoA Carboxylase↗

Platelet serotonin and plasma tryptophan in depressed patients: effect of drug treatment and clinical outcome.

Platelet serotonin and plasma tryptophan were studied in healthy subjects and in depressed patients before and during their antidepressant drug treatment. Before treatment, mean platelet serotonin level was normal in depressed patients compared with healthy subjects while a significant decrease in patients' plasma TRP was noted (t = 6.0, p < .001). The concentrations of platelet 5-HT level did not correlate with either plasma TRP or with clinical variables, that is, AMDP depression and AMDP anxiety scores. Antidepressant drugs treatment decreased platelet 5-HT level (ANOVA F = 8.27, p < .001) whatever the clinical outcome of the patient, whereas the changes observed in plasma TRP were positively related to the mood state change. These results suggest that platelet serotonin could be a good pharmacological model but has no relevance concerning the mood state.

Affect↗

Skin irritant reactivity following experimental cumulative irritant contact dermatitis.

Despite the frequency of irritant contact dermatitis, very little is known about the duration of barrier function impairment following cumulative irritant contact dermatitis. We studied post-irritation irritant reactivity by assessing the response to SLS irritation in previously irritated sites. Cumulative irritant contact dermatitis was induced on the forearms of 15 volunteers aged 18 to 50 years by repeated occluded application of 0.5% SLS 1 h per day over 3 weeks. 3, 6 and 9 weeks later, previously irritated and unirritated control sites were challenged with 2% SLS under occlusion for 23 h. Irritation was assessed by visual scoring, transepidermal water loss (TEWL) as an indicator of epidermal barrier function, and capacitance as a parameter of epidermal water content. While no difference in irritant reactivity between pre-irritated and unirritated sites was observed 3 weeks following irritant contact dermatitis, there was a significant hyporeactivity of previously irritated skin as expressed by clinical scores, TEWL and capacitance at 6 and 9 weeks. Our results indicate that epidermal barrier function remains altered even 9 weeks after cumulative irritant contact dermatitis. With regard to patch testing, post-irritation hyporeactivity might be a cause of false-negative tests on previously irritated sites.

Adolescent↗

Application of dual-digitonin-pulse perfusion to the study of hepatic mRNA zonation.

Heterogeneous zonation of hepatic protein expression over the liver lobule has been recognized by using several analytical techniques, including microdissection, selective cell isolation, immunohistochemistry and hybridization of mRNA in situ. We previously employed the technique of dual-digitonin-pulse perfusion for the highly selective collection and analysis of periportal and perivenous soluble protein. In the present work we have now documented the feasibility of the application of this technique to the study of zonal distribution of mRNA. By using a split-stream design, both protein and RNA fractions can be simultaneously collected from hepatic zones. High-quality RNA (average yield approximately 9-33 micrograms of total RNA per mg of eluted protein) is obtained for analysis. As analysed by immunoblotting and Northern-blot analysis, the zonal distribution of several important cytosolic metabolic enzymes and their mRNAs can be documented. This technique is also applicable to the study of mRNAs for organelle- and membrane-associated proteins that are not recoverable with this digitonin-lysis technique. The application of this experimental technique should allow further molecular insight into the mechanisms underlying zonation of hepatic function.

Animals↗