Location of obstetric anal sphincter injury scars on translabial tomographic ultrasound.

OBJECTIVE: Obstetric anal sphincter injury (OASI) is a common preventable cause of anal incontinence. Both diagnosis and primary repair of OASI are often suboptimal, partly owing to the absence of effective clinical audit. The aim of this study was to evaluate the location of scars or defects of the external anal sphincter (EAS), diagnosed by translabial ultrasound (TLUS), following primary OASI repair. METHODS: This was a retrospective analysis of 309 women who were seen at a tertiary obstetric unit after primary repair of OASI between June 2012 and May 2019. All women underwent a standardized interview, including St Mark's incontinence score, followed by clinical examination and TLUS assessment within 2-9 months after OASI repair. Postprocessing of TLUS volume datasets was performed by an investigator who was blinded to all other information. Tomographic ultrasound imaging was used to evaluate the presence of a scar or defect in the proximal and distal parts of the EAS. Women were classified into four groups according to the imaging findings: (1) no visible defect or distortion (likely false positive); (2) only proximal OASI; (3) only distal OASI; and (4) both proximal and distal OASI. RESULTS: Of the 309 women seen during the study period, 34 were excluded because they were referred for reasons other than recent (< 1 year) OASI, 16 owing to missing data and four owing to poor image quality, leaving 255 patients for analysis. Women were seen on average 0.25 ± 0.1 years after the index birth, and their mean age at delivery was 29.1 ± 4.6 years. Anal incontinence was reported by 97 (38.0%) women. A scar or defect was seen only in the proximal part of the EAS in 64 (25.1%) women and only in the distal part in 19 (7.5%) (P < 0.001). In 165 (64.7%) women, the damage affected both the proximal and distal EAS. CONCLUSIONS: EAS scars after primary OASI repair commonly affect the entire length of the EAS; however, partial tears seem to be more likely to occur proximally. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Correcting the axial shrinkage of skeletal muscle thick sections visualized by confocal microscopy.

Confocal microscopy is a suitable method for measurements and visualization of skeletal muscle fibres and the neighbouring capillaries. When using 3D images of thick sections the tissue deformation effects should be avoided. We studied the deformation in thick sections of the rat skeletal muscle from complete stacks of images captured with confocal microscope. We measured the apparent thickness of the stacks and compared it to the slice thickness deduced from calibrated microtome settings. The ratio of both values yielded the axial scaling factor for every image stack. Careful sample preparation and treatment of the tissue cryosections with cold Ringer solution minimize the tissue deformation. We conclude that rescaling by the inverse of the axial scaling factor of the stack of optical slices in the direction of the microscope optical axis satisfactorily corrects the axial deformation of skeletal muscle samples.

Associations of Maternal Complaints to Levator Ani Muscle Trauma within 9 Months after Vaginal Birth: A Prospective Observational Cohort Study.

Introduction: Pelvic floor trauma in the form of partial or complete avulsions of the levator ani muscle (LAM) affects 6-42% of women after vaginal birth and can cause tremendous long-term morbidity. Many studies assessed morphological pelvic floor trauma after childbirth but lacked to evaluate women's associated short-term complaints. A proper assessment of trauma and subjective complaints after birth could help to assess possible associations between them and their relevance to women's daily life. Therefore, we aimed to assess women's complaints within the first months after birth in association to their LAM trauma. Materials and Methods: Between 3/2017 and 4/2019, we prospectively evaluated vaginal births of 212 primiparous women with singletons in vertex presentation ≥ 36 + 0 gestational weeks for levator ani muscle (LAM) trauma by translabial ultrasound, for pelvic organ prolapse by clinical examination, and for urogynecological complaints using questionnaires 1-4 days (P1), 6-10 weeks (P2), and 6-9 months (P3) after birth. The questionnaires were self-designed but oriented to and modified from validated questionnaires. Women's complaints were evaluated for P1-P3 according to their LAM trauma state. Results: At P1, 67% of women showed an intact LAM, whereas 14.6% presented a hematoma, 6.6% a partial avulsion (PAV), and 11.8% a complete avulsion (CAV). At P2, 75.9% showed an intact LAM, 9.9% a PAV, and 14.2% a CAV. At P3, 72.9% of women with a LAM trauma in P1 and/or P2 were assessed with 21.6% being intact and 39.2% having a PAV and CAV, respectively. Obstetrical and baseline characteristics differed slightly between the groups. When comparing the time before and during pregnancy with the time after childbirth, birth itself affected women's complaints in all LAM state groups, but the presence of a LAM trauma, especially a CAV, had more negative effects. Conclusions: Vaginal birth changes the anatomical structure of the maternal birth canal and genital tract, and it alters women's perceptions and body function. In our study, LAM trauma did not change these effects tremendously within the first months. Therefore, other maternal, fetal, and obstetrical factors need consideration for the explanation of maternal complaints, in addition to long-term effects of trauma and dysfunction of the LAM and other birth canal structures.

Growth and differentiation of alveolar bone cells in tissue-engineered constructs and monolayer cultures.

The ability to enhance bone regeneration by implanting autologous osteoblasts in combination with an appropriate scaffold would be of great clinical interest. The aim of our study was to compare the growth and differentiation of alveolar bone cells in tissue-engineered constructs and in monolayer cultures, as the basis for developing procedures for routine preparation of bone-like tissue constructs. Alveolar bone tissue was obtained from four human donors and explant cultures of the cells were established. Expanded cells were seeded on macroporous hydroxyapatite granules, and cultured in medium supplemented with osteogenic differentiation factors for up to 3 weeks. Control monolayer cultures were established in parallel, and cultured in media with or without osteogenic supplements. Cell proliferation, alkaline phosphatase (AP) activity and gene expression of AP, osteopontin and osteocalcin were determined under different culture conditions at weekly intervals. Cells in tissue constructs exhibited growth patterns similar to those in control monolayer cultures: enhanced proliferation was noted during the first 2 weeks of cultivation, followed by a decrease in cell numbers. AP activity at 3 weeks was higher in all cultures in osteogenic medium than in control medium. Gene expression levels were stable in monolayer cultures in both types of media whereas, in tissue constructs, they exhibited patterns of osteogenic differentiation. Light and scanning electron microscopy examination of the cell-seeded constructs showed uniform cell distribution, as well as cell attachment and growth into the interior region of the hydroxyapatite granules. Our results show that bone-like constructs with viable cells exhibiting differentiated phenotype can be prepared by cultivation of alveolar-bone cells on the tested hydroxyapatite granules.

Presenilin PS1∆E9 disrupts mobility of secretory organelles in rat astrocytes.

AIM: Alzheimer's disease (AD) is largely considered a neuron-derived insult, but also involves failure of astroglia. A recent study indicated that mutated presenilin 1 (PS1M146V), a putative endoplasmic reticulum (ER) Ca2+ channel with decreased Ca2+ conductance, impairs the traffic of astroglial peptidergic vesicles. Whether other pathogenically relevant PS1 mutants, such as PS1ΔE9, which code for ER channel with putative increased Ca2+ conductance, similarly affect vesicle traffic, is unknown. METHODS: Here, we cotransfected rat astrocytes with plasmids encoding mutant PS1ΔE9 and atrial natriuretic peptide or vesicular glutamate transporter 1 tagged with fluorescent proteins (pANP.emd or pVGLUT1-EGFP respectively), to microscopically examine whether alterations in vesicle mobility and Ca2+ -regulated release of gliosignalling molecules manifest as a general vesicle-based defect; control cells were transfected to co-express exogenous or native wild-type PS1 and pANP.emd or pVGLUT1-EGFP. The vesicle mobility was analysed at rest and after ATP stimulation that increased intracellular calcium activity. RESULTS: In PS1ΔE9 astrocytes, spontaneous mobility of both vesicle types was reduced (P < .001) when compared to controls. Post-stimulatory recovery of fast vesicle mobility was hampered in PS1ΔE9 astrocytes. The ATP-evoked peptide release was less efficient in PS1ΔE9 astrocytes than in the controls (P < .05), as was the pre-stimulatory mobility of these vesicles. CONCLUSION: Although the PS1 mutants PS1M146V and PS1ΔE9 differently affect ER Ca2+ conductance, our results revealed a common, vesicle-type indiscriminate trafficking defect in PS1ΔE9 astrocytes, indicating that reduced secretory vesicle-based signalling is a general deficit in AD astrocytes.

Magnetic interactions and in vitro study of biocompatible hydrocaffeic acid-stabilized Fe-Pt clusters as MRI contrast agents.

A detailed magnetic study of separated Fe-Pt NPs and Fe-Pt clusters was performed to predict their optimal size and morphology for the maximum saturation magnetization, a factor that is known to influence the performance of a magnetic-resonance-imaging (MRI) contrast agent. Excellent stability and biocompatibility of the nanoparticle suspension was achieved using a novel coating based on hydrocaffeic acid (HCA), which was confirmed with a detailed Fourier-transform infrared spectroscopy (FTIR) study. An in vitro study on a human-bladder papillary urothelial neoplasm RT4 cell line confirmed that HCA-Fe-Pt nanoparticles showed no cytotoxicity, even at a very high concentration (550 µg Fe-Pt per mL), with no delayed cytotoxic effect being detected. This indicates that the HCA coating provides excellent biocompatibility of the nanoparticles, which is a prerequisite for the material to be used as a safe contrast agent for MRI. The cellular uptake and internalization mechanism were studied using ICP-MS and TEM analyses. Furthermore, it was shown that even a very low concentration of Fe-Pt nanoparticles (<10 µg mL-1) in the cells is enough to decrease the T 2 relaxation times by 70%. In terms of the MRI imaging, this means a large improvement in the contrast, even at a low nanoparticle concentration and an easier visualization of the tissues containing nanoparticles, proving that HCA-coated Fe-Pt nanoparticles have the potential to be used as an efficient and safe MRI contrast agent.

Hybrid FePt/SiO2/Au nanoparticles as a theranostic tool: in vitro photo-thermal treatment and MRI imaging.

We have produced an innovative, theranostic material based on FePt/SiO2/Au hybrid nanoparticles (NPs) for both, photo-thermal therapy and magnetic resonance imaging (MRI). Furthermore, a new synthesis approach, i.e., Au double seeding, for the preparation of Au nanoshells around the FePt/SiO2 cores, is proposed. The photo-thermal and the MRI response were first demonstrated on an aqueous suspension of hybrid FePt/SiO2/Au NPs. The cytotoxicity together with the internalization mechanism and the intracellular fate of the hybrid NPs were evaluated in vitro on a normal (NPU) and a half-differentiated cancerous cell line (RT4). The control samples as well as the normal cell line incubated with the NPs showed no significant temperature increase during the in vitro photo-thermal treatment (ΔT < 0.8 °C) and thus the cell viability remained high (∼90%). In contrast, due to the high NP uptake by the cancerous RT4 cell line, significant heating of the sample was observed (ΔT = 4 °C) and, consequently, after laser irradiation the cell viability dropped significantly to ∼60%. These results further confirm that the hybrid FePt/SiO2/Au NPs developed in the scope of this work were not only efficient but also highly selective photo-thermal agents. Furthermore, the improvement in the contrast and the easier distinction between the healthy and the cancerous tissues were clearly demonstrated with in vitro MRI experiments, proving that hybrid NPs have an excellent potential to be used as contrast agents.

Screening of gestational diabetes mellitus in early pregnancy by oral glucose tolerance test and glycosylated fibronectin: study protocol for an international, prospective, multicentre cohort trial.

INTRODUCTION: As the accurate diagnosis and treatment of gestational diabetes mellitus (GDM) is of increasing importance; new diagnostic approaches for the assessment of GDM in early pregnancy were recently suggested. We evaluate the diagnostic power of an 'early' oral glucose tolerance test (OGTT) 75 g and glycosylated fibronectin (glyFn) for GDM screening in a normal cohort. METHODS AND ANALYSIS: In a prospective cohort study, 748 singleton pregnancies are recruited in 6 centres in Switzerland, Austria and Germany. Women are screened for pre-existing diabetes mellitus and GDM by an 'early' OGTT 75 g and/or the new biomarker, glyFn, at 12-15 weeks of gestation. Different screening strategies are compared to evaluate the impact on detection of GDM by an OGTT 75 g at 24-28 weeks of gestation as recommended by the International Association of Diabetes and Pregnancy Study Groups (IADPSG). A new screening algorithm is created by using multivariable risk estimation based on 'early' OGTT 75 g and/or glyFn results, incorporating maternal risk factors. Recruitment began in May 2014. ETHICS AND DISSEMINATION: This study received ethical approval from the ethics committees in Basel, Zurich, Vienna, Salzburg and Freiburg. It was registered under http://www.ClinicalTrials.gov (NCT02035059) on 12 January 2014. Data will be presented at international conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT02035059.

FM1-43 measurements of local exocytotic events in rat melanotrophs.

We have explored the existence of fusion- and secretion-competent sites on the plasma membrane of peptide secreting rat pituitary melanotrophs at rest, and following stimulation with glutamate. We monitored changes in fluorescence of FM1-43, a styryl dye which labels plasma membrane. The results show spontaneous local increases in FM1-43 reporting changes in membrane surface area due to cumulative exocytosis. Addition of glutamate, further increased the occurrence of these events. Statistical analysis of local FM1-43 fluorescence changes suggests that this is due to the recruitment of inactive exocytotic domains and due to the stimulation of already active exocytotic domains.

Establishment and characterization of primary and subsequent subcultures of normal mouse urothelial cells.

In this study, we report a reliable technique for the harvest, cultivation and expansion of monoculture of NMU. The NMU were harvested by two methods, directly from the urothelium in vivo and indirectly from the urothelial outgrowths of bladder explant cultures. Primary cultures and subsequent subcultures were propagated in the mixture of media MCDB 153 and Advanced-DMEM, and conditioned medium. Primary urothelial cells required an initial plating density of 1 x 10(5) viable cells/cm2 for survival, while passaged cells needed lower plating densities (1 x 10(4) viable cells per cm2). The cultured cells were identified as urothelial by their epithelioid morphology and by the positive immunofluorescence labelling of tight junctional proteins, occludin and ZO-1, adherens protein E-cadherin and cytoskeletal protein cytokeratin 7. Markers of highly differentiated urothelial cells, cytokeratin 20 and uroplakins, were not expressed. Furthermore, the immunofluorescence labelling of occludin and cytokeratin 7 was not detected in later passages when urothelial cells replicated at a high rate. In spite of the use of conditioned medium derived from V79 fibroblast cell culture supernatant, the NMU in the primary cultures and subsequent subcultures expressed a basal/intermediate cell phenotype. In conclusion, we demonstrate that homogeneous long-term culture of NMU can be developed. Since powerful transgenic tools exist to manipulate the mouse genome, our findings should help design the mouse in vitro systems for studying the control mechanisms of urothelial cell proliferation, stratification and differentiation in health and disease.

Uterus Wrapping: A Novel Concept in the Management of Uterine Atony during Cesarean Delivery.

Uterine atony during cesarean delivery is a serious cause of maternal morbidity and mortality. Management strategies include medical treatment with uterotonic agents, manual compression of the uterus, and interventional or surgical procedures. A novel technique to compress the uterus by wrapping it with an elastic bandage and its outcome in 3 cases of uterine atony during cesarean section are presented. Our novel method of intermittent wrapping of the uterus during cesarean delivery seems to be a successful additional approach in the management of uterine atony during cesarean delivery and may be an alternative treatment option to other compressing procedures in order to avoid high blood loss and last but not least postpartum hysterectomy.

Two different mutations in the cytoplasmic domain of the integrin beta 4 subunit in nonlethal forms of epidermolysis bullosa prevent interaction of beta 4 with plectin.

The integrin alpha 6 beta 4 plays a crucial role in the assembly and maintenance of hemidesmosomes. Previous work has shown that the recruitment of plectin into hemidesmosomes is dependent on beta 4 and involves a region of the beta 4 cytoplasmic domain, which contains the first two fibronectin (FNIII) repeats and a short region of the connecting segment. Two missense mutations (R1225H and R1281W) in beta 4 that are responsible for nonlethal forms of epidermolysis bullosa are located in the second FNIII repeat. One of them is confined to a loop region that connects two beta strands (EC') whereas the other is located at the N-terminal end of the second FNIII repeat. We here report that these mutations render beta 4 unable to interact with plectin and prevent the localization of plectin in hemidesmosomes. Substitution of a lysine residue (K1279W) that forms part of the same loop as R1281 had no effect on the ability of beta 4 to recruit plectin. Furthermore, we show that an extended loop structure in beta 4, composed of the amino acids DDN (1262--1264), which resembles the RGD integrin-binding loop in fibronectin, is not involved in the binding to plectin. These results further demonstrate that binding of beta 4 to plectin is essential for the proper formation and function of hemidesmosomes and that loss of the interaction between beta 4 and plectin is associated with a mild form of epidermolysis bullosa.

Apoptosis triggered redistribution of caspase-9 from cytoplasm to mitochondria.

Caspase-9 is an apoptosis initiator protease activated as a response to the mitochondrial damage in the cytoplasmic complex apoptosome. By fluorescence labelling of proteins, confocal microscopy and subcellular fractionations we demonstrate that caspase-9 is in the cytoplasm of non-apoptotic pituitary cells. The activation of apoptosis with rotenone triggers the redistribution of caspase-9 to mitochondria. Experiments using the general caspase inhibitor z-VAD.fmk and the specific caspase-9 inhibitor z-LEHD.fmk show that the caspase-9 redistribution is a regulated process and requires the activity of a caspase other than the caspase-9. We propose that this spatial regulation is required to control the activity of caspase-9.

Automated high through-put colocalization analysis of multichannel confocal images.

The laser scanning confocal microscope (LSCM) generates images of multiple labelled fluorescent samples. Colocalization of fluorescent labels is frequently examined. Here we present an example where localization of fluorescent analogues of cloned protein were referenced to fluorescent antibodies directed against the proteins of cellular compartments. Colocalization is usually evaluated by visual inspection of signal overlap or by using commercially available software tools, but there are limited possibilities to automate the analysis of large amounts of data. We developed a simple tool using Matlab to automate the colocalization procedure and to exclude the biased estimations resulting from visual inspections of images. The script in Matlab language code automatically imports confocal images and converts them into arrays. The contrast of all images is uniformly set by linearly reassigning the values of pixel intensities to use the full 8-bit range (0-255). Images are binarized on several threshold levels. The area above a certain threshold level is summed for each channel of the image and for colocalized regions. As a result, count of pixels above several threshold levels in any number of images is saved in an ASCII file. In addition Pearson's r correlation coefficient is calculated for fluorescence intensities of both confocal channels. Using this approach quick quantitative analysis of colocalization of hundreds of images is possible. In addition, such automated procedure is not biased by the examiner's subject visualization.

Alterations of calcium homoeostasis in cultured rat astrocytes evoked by bioactive sphingolipids.

AIM: In the brain, alterations in sphingolipid metabolism contribute to several neurological disorders; however, their effect on astrocytes is largely unknown. Here, we identified bioactive sphingolipids that affect intracellular free calcium concentration ([Ca(2+)]i), mobility of peptidergic secretory vesicles, signalling pathways involved in alterations of calcium homoeostasis and explored the relationship between the stimulus-evoked increase in [Ca(2+)]i and attenuation of vesicle mobility. METHODS: Confocal time-lapse images were acquired to explore [Ca(2+)]i signals, the mobility of fluorescently tagged peptidergic vesicles and the structural integrity of the microtubules and actin filaments before and after the addition of exogenous sphingolipids to astrocytes. RESULTS: Fingolimod (FTY720), a recently introduced therapeutic for multiple sclerosis, and sphingosine, a releasable constituent of membrane sphingolipids, evoked long-lasting increases in [Ca(2+)]i in the presence and absence of extracellular Ca(2+); the evoked responses were diminished in the absence of extracellular Ca(2+). Activation of phospholipase C and inositol-1,4,5-triphosphate receptors was necessary and sufficient to evoke increases in [Ca(2+)]i as revealed by the pharmacologic inhibitors; Ca(2+) flux from the extracellular space intensified these responses several fold. The lipid-evoked increases in [Ca(2+)]i coincided with the attenuated vesicle mobility. High and positive correlation between increase in [Ca(2+)]i and decrease in peptidergic vesicle mobility was confirmed independently in astrocytes exposed to evoked, transient Ca(2+) signalling triggered by purinergic and glutamatergic stimulation. CONCLUSION: Exogenously added cell-permeable sphingosine-like lipids exert complex, Ca(2+)-dependent effects on astrocytes and likely alter their homeostatic function in vivo.

Signaling events mediated by α3ß1 integrin are essential for mammary tumorigenesis.

The constitutive activation of ß-catenin signaling in the mammary basal epithelial cell layer in transgenic K5ΔNßcat mice leads to basal-type tumor development. Integrins of the ß1 family and integrin-mediated signaling events have an important role in breast tumor growth and progression. We show here that the deletion of α3ß1 integrin, a major laminin receptor, from the basal layer of the mammary epithelium of K5ΔNßcat mice completely prevented the tumorigenesis induced by ß-catenin signaling. Moreover, the depletion of α3ß1 integrin from a spontaneously transformed mouse mammary basal epithelial cell line (MEC) prevented the cells from forming colonies in soft agar and greatly reduced tumor development in orthotopic grafts. Inhibition of the integrin signaling intermediates Rac1 or PAK1 (P21-activated Kinase 1) in MEC affected tumor cell growth in soft agar, whereas the expression of activated forms of these effectors in α3-depleted cells rescued the capacity of these cells to grow in non-adherent conditions. Similarly, the tumorigenic potential of α3-depleted cells was restored by the expression of activated PAK1, as assessed by orthotopic transplantation assay. In three-dimensional Matrigel culture, MEC survival and proliferation were affected by the depletion of α3ß1 integrin, which also significantly decreased the activation of focal adhesion kinase (FAK), mitogen-activated protein kinase (MAPK) and c-Jun NH2-terminal kinase (JNK). Our data suggest that the activation of signaling cascades downstream from α3ß1 and involving the Rac1/PAK1 pathway, MAPK and JNK, promotes prosurvival and proproliferative signals required for the malignant growth of basal mammary epithelial cells, providing further insight into the molecular mechanisms underlying breast cancer initiation and progression.

Aluminium-induced changes of fusion pore properties attenuate prolactin secretion in rat pituitary lactotrophs.

Hormone secretion is mediated by Ca(2+)-regulated exocytosis. The key step of this process consists of the merger of the vesicle and the plasma membranes, leading to the formation of a fusion pore. This is an aqueous channel through which molecules stored in the vesicle lumen exit into the extracellular space on stimulation. Here we studied the effect of sub-lethal dose of aluminium on prolactin secretion in isolated rat pituitary lactotrophs with an enzyme immunoassay and by monitoring electrophysiologically the interaction of a single vesicle with the plasma membrane in real time, by monitoring membrane capacitance. After 24-h exposure to sub-lethal AlCl(3) (30 µM), the secretion of prolactin was reduced by 14±8% and 46±11% under spontaneous and K(+)-stimulated conditions, respectively. The frequency of unitary exocytotic events, recorded by the high-resolution patch-clamp monitoring of membrane capacitance, a parameter linearly related to the membrane area, under spontaneous and stimulated conditions, was decreased in aluminium-treated cells. Moreover, while the fusion pore dwell-time was increased in the presence of aluminium, the fusion pore conductance, a measure of fusion pore diameter, was reduced, both under spontaneous and stimulated conditions. These results suggest that sub-lethal aluminium concentrations reduce prolactin secretion downstream of the stimulus secretion coupling by decreasing the frequency of unitary exocytotic events and by stabilizing the fusion pore diameter to a value smaller than prolactin molecule, thus preventing its discharge into the extracellular space.

Amyotrophic lateral sclerosis immunoglobulins G enhance the mobility of Lysotracker-labelled vesicles in cultured rat astrocytes.

AIM: We examined the effect of purified immunoglobulins G (IgG) from patients with amyotrophic lateral sclerosis (ALS) on the mobility and exocytotic release from Lysotracker-stained vesicles in cultured rat astrocytes. METHODS: Time-lapse confocal images were acquired, and vesicle mobility was analysed before and after the application of ALS IgG. The vesicle counts were obtained to assess cargo exocytosis from stained organelles. RESULTS: At rest, when mobility was monitored for 2 min in bath with Ca(2+), two vesicle populations were discovered: (1) non-mobile vesicles (6.1%) with total track length (TL) < 1 µm, averaging at 0.33 ± 0.01 µm (n = 1305) and (2) mobile vesicles (93.9%) with TL > 1 µm, averaging at 3.03 ± 0.01 µm (n = 20,200). ALS IgG (0.1 mg mL(-1)) from 12 of 13 patients increased the TL of mobile vesicles by approx. 24% and maximal displacement (MD) by approx. 26% within 4 min, while the IgG from control group did not alter the vesicle mobility. The mobility enhancement by ALS IgG was reduced in extracellular solution devoid of Ca(2+), indicating that ALS IgG vesicle mobility enhancement involves changes in Ca(2+) homeostasis. To examine whether enhanced mobility relates to elevated Ca(2+) activity, cells were stimulated by 1 mm ATP, a cytosolic Ca(2+) increasing agent, in the presence (2 mm) and in the absence of extracellular Ca(2+). ATP stimulation triggered an increase in TL by approx. 7% and 12% and a decrease in MD by approx. 11% and 1%, within 4 min respectively. Interestingly, none of the stimuli triggered the release of vesicle cargo. CONCLUSION: Amyotrophic lateral sclerosis-IgG-enhanced vesicle mobility in astrocytes engages changes in calcium homeostasis.

Caffeine and theophylline block insulin-stimulated glucose uptake and PKB phosphorylation in rat skeletal muscles.

AIM: Caffeine and theophylline inhibit phosphatidylinositol 3-kinase (PI3-kinase) activity and insulin-stimulated protein kinase B (PKB) phosphorylation. Insulin-stimulated glucose uptake involves PI3-kinase/PKB, and the aim of the present study was to test the hypothesis that caffeine and theophylline inhibit insulin-stimulated glucose uptake in skeletal muscles. METHODS: Rat epitrochlearis muscles and soleus strips were incubated with insulin and different concentrations of caffeine and theophylline for measurement of glucose uptake, force development and PKB phosphorylation. The effect of caffeine was also investigated in muscles stimulated electrically. RESULTS: Caffeine and theophylline completely blocked insulin-stimulated glucose uptake in both soleus and epitrochlearis muscles at 10 mm. Furthermore, insulin-stimulated PKB Ser(473) and Thr(308) and GSK-3beta Ser(9) phosphorylation were blocked by caffeine and theophylline. Caffeine reduced and theophylline blocked insulin-stimulated glycogen synthase activation. Caffeine stimulates Ca(2+) release and force development increased rapidly to 10-20% of maximal tetanic contraction. Dantrolene (25 microm), a well-known inhibitor of Ca(2+)-release, prevented caffeine-induced force development, but caffeine inhibited insulin-stimulated glucose uptake in the presence of dantrolene. Contraction, like insulin, stimulates glucose uptake via translocation of glucose transporter-4 (GLUT4). Caffeine and theophylline reduced contraction-stimulated glucose uptake by about 50%, whereas contraction-stimulated glycogen breakdown was normal. CONCLUSION: Caffeine and theophylline block insulin-stimulated glucose uptake independently of Ca(2+) release, and the likely mechanism is via blockade of insulin-stimulated PI3-kinase/PKB activation. Caffeine and theophylline also reduced contraction-stimulated glucose uptake, which occurs independently of PI3-kinase/PKB, and we hypothesize that caffeine and theophylline also inhibit glucose uptake in skeletal muscles via an additional and hitherto unknown molecule involved in GLUT4 translocation.

Impact of the CYP2D6 genotype on the clinical effects of metoprolol: a prospective longitudinal study.

After administration of metoprolol, plasma concentrations of the drug are markedly higher in CYP2D6 poor metabolizers (PMs) than in non-PMs. In a prospective double-blind 3-month study, we investigated whether this translates into differences in metoprolol's effects after initiation of therapy. Despite administering equal doses to PMs and non-PMs, metoprolol plasma concentrations were 4.9-fold higher in the PM group. Metoprolol evoked significantly and persistently greater reductions in heart rate, diastolic blood pressure, and mean arterial pressure in PMs than in non-PMs. It appears, therefore, that the CYP2D6 genotype contributes to interindividual differences in metoprolol response.