Fracture prevention in COPD patients; a clinical 5-step approach

Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV₁ < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture.     

Glucose and fatty acids synergize to promote B-cell apoptosis through activation of glycogen synthase kinase 3β independent of JNK activation

Background

The combination of elevated glucose and free-fatty acids (FFA), prevalent in diabetes, has been suggested to be a major contributor to pancreatic β-cell death. This study examines the synergistic effects of glucose and FFA on β-cell apoptosis and the molecular mechanisms involved. Mouse insulinoma cells and primary islets were treated with palmitate at increasing glucose and effects on apoptosis, endoplasmic reticulum (ER) stress and insulin receptor substrate (IRS) signaling were examined.

Principal Findings

Increasing glucose (5–25 mM) with palmitate (400 µM) had synergistic effects on apoptosis. Jun NH2-terminal kinase (JNK) activation peaked at the lowest glucose concentration, in contrast to a progressive reduction in IRS2 protein and impairment of insulin receptor substrate signaling. A synergistic effect was observed on activation of ER stress markers, along with recruitment of SREBP1 to the nucleus. These findings were confirmed in primary islets. The above effects associated with an increase in glycogen synthase kinase 3β (Gsk3β) activity and were reversed along with apoptosis by an adenovirus expressing a kinase dead Gsk3β.

Conclusions/Significance

Glucose in the presence of FFA results in synergistic effects on ER stress, impaired insulin receptor substrate signaling and Gsk3β activation. The data support the importance of controlling both hyperglycemia and hyperlipidemia in the management of Type 2 diabetes, and identify pancreatic islet β-cell Gsk3β as a potential therapeutic target.     

Identification of bacteria with beta-galactosidase activity in faeces from lactase non-persistent subjects

Previous studies suggest that, besides the maldigestion of lactose in the small intestine, the colonic processing of lactose might play a role in lactose intolerance. beta-Galactosidase is the bacterial enzyme which catalyzes the first step of lactose fermentation in the colon. We propose a practical method to differentiate and identify bacteria with beta-galactosidase activity in faeces which combines a colony-lift filter assay with X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) as substrate for differentiation and the fluorescent in situ hybridization technique for identification. The method was applied to faeces from lactase non-persistent subjects. After 28 subjects had undergone one glucose and two lactose challenges, consistent intolerant (n=5) and tolerant (n=7) groups were defined according to their symptom scores. Of the 28 faecal samples, 80.6% (mean, SD: 12.1, range: 47.8-100%) of the total cultured bacteria were found to possess beta-galactosidase activity, which indicates that the bacterial beta-galactosidase is abundant in the colon. The tolerant and intolerant groups did not differ in the percentage or composition of the bacteria with beta-galactosidase activity or beta-galactosidase activity in faeces. Results suggest that the percentage or composition of the bacteria with beta-galactosidase activity in faeces do not play a role in lactose intolerance.     

Photoperiod and temperature differentially regulate the expression of two dehydrin genes during overwintering of birch (Betula pubescens Ehrh.)

The overwintering of trees in northern areas depends on processes regulated by photoperiod and temperature. To identify the physiological and genetic factors involved in this environmental control, three latitudinal ecotypes of pubescent birch (Betula pubescens Ehrh.) growing in a common garden experiment were used. Each ecotype responded to the shortening of the photoperiod according to its specific critical daylength, resulting in the induction of freezing tolerance and dehydration of buds first in the northern ecotype, followed by the central and southern ecotypes, respectively. By contrast, there was no clear difference in the timing of dormancy release, bud rehydration, and deacclimation in the spring, suggesting that these traits were controlled mainly by temperature. To elucidate the role of dehydrins (DHN) in the overwintering process, two DHN genomic clones were isolated from pubescent birch and expression of the corresponding genes, both in field and under controlled conditions, was characterized. BpuDhn1 was found to encode an Y(n)K(n)-type of basic DHN, while BpuDhn2 encoded an acidic, SK(n)-type of DHN. In field-grown trees the level of BpuDhn1 increased in buds during the autumn, while the level of BpuDhn2 was highest during the coldest winter months. Under controlled conditions BpuDhn1 increased in response to the combined effect of short daylength and low, non-freezing temperatures whereas the expression of BpuDhn2 was mainly controlled by low temperature while photoperiod had less effect on its expression. These results suggest that DHNs participate in the sensitive environmental regulation of the overwintering process in birch.     

Molecular diversity, cultivation, and improved detection by fluorescent in situ hybridization of a dominant group of human gut bacteria related to Roseburia spp. or Eubacterium rectale

Phylogenetic analysis was used to compare 16S rRNA sequences from 19 cultured human gut strains of Roseburia and Eubacterium rectale with 356 related sequences derived from clone libraries. The cultured strains were found to represent five of the six phylotypes identified. A new oligonucleotide probe, Rrec584, and the previous group probe Rint623, when used in conjunction with a new helper oligonucleotide, each recognized an average of 7% of bacteria detected by the eubacterial probe Eub338 in feces from 10 healthy volunteers. Most of the diversity within this important group of butyrate-producing gut bacteria can apparently be retrieved through cultivation.     

Unchanged beta-adrenergic stimulation of cardiac L-type calcium channels in Ca v 1.2 phosphorylation site S1928A mutant mice

Phosphorylation of serine 1928 (Ser(1928)) of the cardiac Ca(v)1.2 subunit of L-type Ca(2+) channels has been proposed as the mechanism for regulation of L-type Ca(2+) channels by protein kinase A (PKA). To test this directly in vivo, we generated a knock-in mouse with targeted mutation of Ser(1928) to alanine. This mutation did not affect basal L-type current characteristics or regulation of the L-type current by PKA and the beta-adrenergic receptor, whereas the mutation abolished phosphorylation of Ca(v)1.2 by PKA. Therefore, our data show that PKA phosphorylation of Ser(1928) of Ca(v)1.2 is not functionally involved in beta-adrenergic stimulation of Ca(v)1.2-mediated Ca(2+) influx into the cardiomyocyte.     

Extensive Set of 16S rRNA-Based Probes for Detection of Bacteria in Human Feces

For the detection of six groups of anaerobic bacteria in human feces, we designed seven new 16S rRNA-based oligonucleotide probes. This set of probes extends the current set of probes and gives more data on the composition of the human gut flora. Probes were designed for Phascolarctobacterium and relatives (Phasco741), Veillonella (Veil223), Eubacterium hallii and relatives (Ehal1469), Lachnospira and relatives (Lach571), and Eubacterium cylindroides and relatives (Ecyl387), and two probes were designed for Ruminococcus and relatives (Rbro730 and Rfla729). The hybridization conditions for the new probes were optimized for fluorescent in situ hybridization, and the probes were validated against a set of reference organisms. The probes were applied to fecal samples of 11 volunteers to enumerate their target bacterial groups. The Phasco741 and Veil223 probes both detected average numbers below 1% of the total number of bacteria as determined with the bacterial kingdom-specific Bact338 probe. The Ecyl387 probe detected about 1.4%, the Lach571 and Ehal1469 probes detected 3.8 and 3.6%, respectively, and a combination of the Rbro730 and Rfla729 probes detected 10.3%. A set of 15 probes consisting of probes previously described and those presented here were evaluated in hybridization with the fecal samples of the same volunteers. Together, the group-specific probes detected 90% of the total bacterial cells.     

Induced resistance: from the basic to the applied.

Induced Resistance in Plants Against Insects and Diseases, Wageningen, The Netherlands, 26–28 April 2001.     

Comparison of methods for the determination of β-aspartylglycine in fecal supernatants of leukemic patients treated with antimicrobial agents

β-Aspartylglycine is an indicator of the absence of bacterial enzymatic activity in the intestinal tract. This study describes and compares four methods — (1) dansylation with thin-layer chromatography, (2) ion-exchange chromatography, (3) thin-layer electrophoresis, (4) high-voltage paper electrophoresis — to determine the concentration of β-aspartylglycine in fecal supernatants of leukemic patients treated with antimicrobial agents.     

Zur Feinstruktur der Plasmodesmen und Plasmakanäle bei Pollenmutterzellen

Zusammenfassung Bei Tomate (Lycopersicum esculentum) und Kürbis (Cucurbita maxima) wurde der Feinbau der zwischen den Pollenmutterzellen bestehenden Plasmaverbindungen elektronenmikroskopisch untersucht.Neben feinen, den Verhältnissen in meristematischen somatischen Zellen entsprechenden Plasmaverbindungen (Plasmodesmen im engeren Sinne, Durchmesser im geometrischen Mittel 253,3 Å) wurden relativ breite, fast durchweg gröbere Cytoplasmaeinschlüsse (Mitochondrien, Vesikel, Potocytose-Bläschen, Dictyosomen usw.) aufweisende Verbin-dungen (Plasmakanäle, Durchmesser im geometrischen Mittel 0,175 ) festgestellt. Elemente des Endoplasmatischen Reticulums finden sich regelmäßig in den Plasmakanälen. Sie lassen sich jedoch häufig auch in größeren Plasmodesmen nachweisen.Weder über den Zeitpunkt der Entstehung, noch über die Entstehungsweise der Plasmakanäle lassen sich bei unserem Pflanzenmaterial konkrete Angaben machen. Gleiches gilt hinsichtlich des Zeitpunktes und der Art, wie die Plasmakanäle schließlich schwinden.Unbekannt ist auch die Art und Weise, wie die Plasmodesmen in Verbindung mit der Bildung der die Pollenmutterzellen bzw. auch die einzelnen Tetradenzellen umhüllenden dicken Callosemembranen schwinden.Bei der Tomate sind die Plasmakanäle bereits vor Aufgabe der Plasmodesmen vorhanden. Andererseits lassen sie sich in späteren Phasen der Tetradenentwicklung nicht mehr nachweisen.Die Beobachtungen werden in Verbindung mit bereits vorliegenden Angaben in der Literatur, insbesondere im Hinblick auf die Bedeutung der Plasmakanäle und ihre Ähnlichkeit mit Siebporen, diskutiert.

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On the fine structure of plasmodesmata and plasma-channels in pollen mother cells (PMC)

Summary The fine structure of plasmatic connections between PMC has been examined by electron microscopy in tomato (Lycopersicum esculentum) and squash (Cucurbita maxima).In addition to plasmodesmata, of geometrical mean diameter 253.3 Å, which correspond to the plasmodesmata in meristematic somatic cells, there are also to be distinguished plasma-channels of geometrical mean diameter 0.175 , which frequently contain cytoplasmic inclusions, such as mitochondria, vesicles, potocytosevesicles, dictyosomata etc. Generally we found elements of the endoplasmic reticulum in the plasma-channels. These elements are also to be found in larger plasmodesmata.We do not know the time nor the manner in which the plasma-channels of our plants originate and disappear. Also it is unknown how the plasmodesmata disappear when the thick callose-membrane is formed around the PMCs and the tetrad-cells.In the tomato the plasma-channels are present before the plasmodesmata disappear. On the other hand they are absent in later stages of tetrad development.The observations are discussed with regard to the possible function of the plasma-channels and their similarity to sievepores.

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Mit 17 Textabbildungen