Overestimate of relative aerobic contribution with maximal accumulated oxygen deficit: a review.

Maximal accumulated oxygen deficit (MAOD) is widely utilized in calculating energy production during supra-maximal exercises. Since its introduction by Medbo et al. in 1988, debate on MAOD existed. The purpose of this review was to summarize the development and description of MAOD and another method of calculating energy production (Pcr-La-O2). We reviewed similar studies on relative aerobic contribution (O2%) and analyzed various results of O2% calculated using MAOD or Pcr-La-O2. An overestimate of O2% was found when using MAOD compared to Pcr-La-O2. The overestimate when using MAOD is likely due to the linear extrapolation of oxygen uptake at supra-maximal intensity, the neglect of anaerobic energy release and the reduced duration of each step in sub-maximal incremental test. Since it is unknown which method provides a more reliable estimation of O2%, an exponential regression function (y=22.404 * ex + 45.176, where y=O2% in percentage, x=duration of the supra-maximal exercise in minute) was drawn from the existing data using both methods.

Maximal lactate steady state in kayaking.

A fixed blood lactate value of 4 mM was commonly used to calculate workload at maximal lactate steady state (MLSS) in kayaking. Our purpose was to measure the actual blood lactate value at MLSS and workload at MLSS in kayaking and assess the validity of using a fixed blood lactate value to calculate the workload at MLSS. 8 junior kayakers (15.1±1.2 years; 179.9±7.3 cm; 72.3±4.9 kg) participated in an incremental workload test and 4-6 sub-maximal constant workload tests (duration of 30 min) on a kayaking ergometer. Blood lactate was measured to calculate the blood lactate value and workload at MLSS. The blood lactate value at MLSS in kayaking was 5.4±0.7 mM. The measured workload at MLSS (112±22 watts) was significantly greater than the calculated workload using a lactate value of 4 mM (104±18 watts, p=0.016). The measured MLSS workload was not significantly different from the calculated workload using a fixed lactate value of 5.4 mM (115±19 watts, p=0.16) or 5.0 mM (113±19 watts, p=0.78) in the incremental tests. A fixed blood lactate value of 5 mM instead of 4 mM might be a better estimate in kayaking given the incremental workload test used in this study.

ER stress in adipocytes inhibits insulin signaling, represses lipolysis, and alters the secretion of adipokines without inhibiting glucose transport.

The endoplasmic reticulum (ER) is the intra-cellular site, where secreted and membrane proteins are synthesized. ER stress and activation of the unfolded protein response (UPR) contribute to insulin resistance and the development of diabetes in obesity. It was shown previously in hepatocytes that the UPR activates c-jun N-terminal kinase (JNK), which phosphorylates insulin receptor substrate (IRS) proteins on serine residues thereby inhibiting insulin signal transduction. Here we describe how ER stress affects insulin signaling and the biological function of adipocytes. In addition to inhibition of IRS we found that ER stress downregulates the expression of the insulin receptor. Concomitantly, insulin-induced activation of Akt/PKB and of ERK1/2 was strongly inhibited. Ectopic expression of IRS1 or IRS2 strongly counteracted the inhibitory effect of ER stress on insulin signaling while pharmacological inhibition of JNK with SP600125 resulted only in a mild improvement. ER stress decreased the secretion of the adipokines adiponectin and leptin, but strongly increased secretion of IL-6. ER stress inhibited expression and insulin-induced phosphorylation of AS160, reduced lipolysis but did not inhibit glucose transport. Finally, supernatants collected from 3T3-L1 adipocytes undergoing ER stress improved or impaired proliferation when used to condition the culture medium of INS-1E beta-cells dependent on the degree of ER stress. It appears that ER stress in adipocytes might initially lead to changes resembling early prediabetic stages, which at least in part support the regulation of systemic energy homeostasis.

Combined radiotherapy and concurrent tumor treating fields (TTFields) for glioblastoma: Dosimetric consequences on non-coplanar IMRT as initial results from a phase I trial.

BACKGROUND: Glioblastoma is a rapidly proliferating tumor. Patients bear an inferior prognosis with a median survival time of 14-16 months. Proliferation and repopulation are a major resistance promoting factor for conventionally fractionated radiotherapy. Tumor-Treating-Fields (TTFields) are an antimitotic modality applying low-intensity (1-3 V/cm), intermediate-frequency (100-300 kHz) alternating electric-fields. More recently interference of TTFields with DNA-damage-repair and synergistic effects with radiotherapy were reported in the preclinical setting. This study aims at examining the dosimetric consequences of TTFields applied during the course of radiochemotherapy. METHODS: Cone-beam-computed-tomography (CBCT)-data from the first seven patients of the PriCoTTF-phase-I-trial were used in a predefined way for dosimetric verification and dose-accumulation of the non-coplanar-intensity-modulated-radiotherapy (IMRT)-treatment-plans as well as geometric analysis of the transducer-arrays by which TTFields are applied throughout the course of treatment. Transducer-array-position and contours were obtained from the low-dose CBCT's routinely made for image-guidance. Material-composition of the electrodes was determined and a respective Hounsfield-unit was assigned to the electrodes. After 6D-fusion with the planning-CT, the dose-distribution was recalculated using a Boltzmann-equation-solver (Acuros XB) and a Monte-Carlo-dose-calculation-engine. RESULTS: Overdosage in the scalp in comparison to the treatment plan without electrodes stayed below 8.5% of the prescribed dose in the first 2 mm below and also in deeper layers outside 1cm2 at highest dose as obtained from dose-volume-histogram comparisons. In the clinical target volume (CTV), underdosage was limited to 2.0% due to dose attenuation by the electrodes in terms of D95 and the effective-uniform-dose. Principal-component-analysis (PCA) showed that the first principal-position-component of the variation of repeated array-placement in the direction of the largest variations and the perpendicular second-component spanning a tangential plane on the skull had a standard deviation of 1.06 cm, 1.23 cm, 0.96 cm, and 1.11 cm for the frontal, occipital, left and right arrays for the first and 0.70 cm, 0.71 cm, 0.79 cm, and 0.68 cm, respectively for the second-principal-component. The variations did not differ from patient-to-patient (p > 0.8, Kruskal-Wallis-tests). This motion led to a diminution of the dosimetric effects of the electrodes. CONCLUSION: From a dosimetric point of view, dose deviations in the CTV due to transducer-arrays were not clinically significant in the first 7 patients and confirmed feasibility of combined adjuvant radiochemotherapy and concurrent TTFields. PriCoTTF Trial: A phase I/II trial of TTFields prior and concomitant to radiotherapy in newly diagnosed glioblastoma. DRKS-ID: DRKS00016667. Date of Registration in DRKS: 2019/02/26. Investigator Sponsored/Initiated Trial (IST/IIT): yes. Ethics Approval/Approval of the Ethics Committee: Approved. (leading) Ethics Committee Nr.: 18-8316-MF, Ethik-Kommission der Medizinischen. Fakultät der Universität Duisburg-Essen. EUDAMED-No. (for studies acc. to Medical Devices act): CIV-18-08-025247.

Molecular identification of virilizer, a gene required for the expression of the sex-determining gene Sex-lethal in Drosophila melanogaster.

Sex-lethal (Sxl) is a central switch gene in somatic sexual development of Drosophila melanogaster. Female-specific expression of Sxl relies on autoregulatory splicing of Sxl pre-mRNA by SXL protein. This process requires the function of virilizer (vir). Besides its role in Sxl splicing, vir is essential for male and female viability and is also required for the production of eggs capable of embryonic development. We have identified vir molecularly and found that it produces a single transcript of 6 kb that is ubiquitously expressed in male and female embryos throughout development. This transcript encodes a nuclear protein of 210 kD that cannot be assigned to a known protein family. VIR contains a putative transmembrane domain, a coiled-coil region and PEST sequences. We have characterized five different alleles of vir. Those alleles that affect both sexes are associated with large truncations of the protein, while alleles that affect only the female-specific functions are missense mutations that lie relatively close to each other, possibly defining a region important for the regulation of Sxl.

The male-determining activity on the Y chromosome of the housefly (Musca domestica L.) consists of separable elements.

In the common housefly, the presence or absence of a male-determining factor, M, is responsible for sex determination. In different strains, M has been found on the Y, on the X, or on any of the five autosomes. By analyzing a Y-autosomal translocation and a ring-shaped, truncated Y chromosome, we could show that M on the Y consists of at least two regions with M activity: One of them can be assigned to the short arm of the Y chromosome (MYS), which is largely C-banding negative, the other region lies on the C-banding positive long arm of the Y, including the centromeric part (MYL). Each region alone behaves as a hypomorphic M factor, causing many carriers to develop as intersexes of the mosaic type instead of as males. When introduced into the female germ line by transplantation of progenitor germ cells (pole cells), the MYS shows an almost complete maternal effect that predetermines 96% of the genotypic female (NoM) animals to develop as males. In contrast, the MYL has largely lost its maternal effect, and most of the NoM animals develop as females. Increasing the amount of product made by either of the two hypomorphic M factors (by combining the MYS and MYL or two MYS) leads to complete male development in almost every case. We thus assume that the Y chromosome carries at least two copies of M, and that these are functionally equivalent.

The metabolisable hexoses D-glucose and D-mannose enhance the expression of IRS-2 but not of IRS-1 in pancreatic beta-cells.

D-glucose regulates maintenance and function of pancreatic beta-cells. Several studies have shown that IRS-2, but not IRS-1, is necessary to maintain and sufficient to expand functional beta-cell mass. We therefore analyzed the expression of IRS-2 and IRS-1 in beta-cells after culture in the presence of various concentrations of D-glucose and other metabolisable or non-metabolisable hexoses. D-glucose increased Irs-2 transcription and IRS-2 accumulation in a dose-dependent manner (1.6 to 25 mmol/l), with a 3-fold increased plateau after 10 h. In contrast, the expression of IRS-1 remained unaffected. D-glucose also induced phosphorylation of IRS-2 while non-metabolisable hexoses did neither affect expression nor phosphorylation. D-glucose-mediated elevation and phosphorylation of IRS-2 were independent of autocrine insulin action although insulin itself could transiently and slightly enhance IRS-2 expression.

Enterobacter cloacae outbreak in the NICU related to disinfected thermometers.

In the first week ot December 1997, an increasing incidence of neonates colonized with multi-drug resistant Enterobacter cloacae (MR-E. cloacae) was observed in the neonatal Intensive care unit of our 950-bed university hospital. Initially, re-enforcement of infection control practices including hand disinfection and cohort isolation seemed to be sufficient to control the outbreak. Nevertheless, an increasing number of newly admitted patients was paralleled by another rise in the incidence of colonized neonates. Since E. cloacae was initially found in urine specimens of the patients, surveillance and environmental cultures were aimed at procedures and instruments that might colonize the gastro-intestinal and/or urinary tract. E, cloacae was isolated from a single cap of an electronic digital thermometer. Despite banning of this possible source, newly admitted neonates still became colonized. The unit was closed for further admissions and a second round of extensive screening was started; this time including all available thermometers and continuous rectal temperature probes. Ready-to-use 'disinfected thermometers and probes were found to be colonized with MR-E. cloacae. Observation of disinfection procedures and a laboratory investigation revealed that 'rushed disinfection with alcohol 80% led to a 1 in 10 chance of thermometers still being contaminated. Furthermore, alcoholic hand rub used for convenience disinfection failed to disinfect thermometers in 40% and 20% of the cases when done in a 'rushed' or 'careful' fashion, respectively. Adequate disinfection of the thermometers led to the control of the outbreak, with no new occurrence of MR-E. cloacae in the following months.

Group specific PCR-detection of potential trichothecene-producing Fusarium-species in pure cultures and cereal samples.

A PCR based assay (Tox5 PCR) which analyses Fusarium species potentially producing trichothecenes was developed using a pair of primers derived from the DNA-sequence of the trichodiene synthase gene (tri5). The primer pair was tested using DNA isolated from a variety of strains representing 64 species and varieties of Fusarium as well as from other fungi, bacteria and cereals. A 658 bp PCR fragment was specifically amplified with DNA isolated from strains of species belonging to the Fusarium sections Discolor, Sporotrichiella, Arthrosporiella, Gibbosum, and "Dlaminia". PCR products obtained were sequenced. Alignment to tri5 sequences given in the literature revealed a high degree of homology. Results of the PCR developed correlated well with literature data on the trichothecene producing capabilities of the respective species. Potential trichothecene producing fusaria were detected in contaminated cereals and malts using the Tox5 PCR assay. Intensity of the signals produced were well correlated with the concentration of deoxynivalenol (DON) in samples of wheat.

Breast-feeding after inferior pedicle reduction mammaplasty.

The breast-feeding practices of a series of postpartum women, who had undergone prior reduction mammaplasty by means of an inferior pedicle approach, are reported in this retrospective study. Also identified are the factors that influenced the decision to breast-feed postoperatively. From a patient pool of 544 individuals who elected to have reduction mammaplasty between 1984 and 1994 (age range, 15 to 35 years), 334 could be contacted and interviewed by means of telephone by using a standardized questionnaire. Successful breast-feeding was defined as the ability to feed for a duration equal to or greater than 2 weeks. Seventy-eight patients had children after their breast reduction surgery. Fifteen of the 78 patients (19.2 percent) breast-fed exclusively, 8 (10.3 percent) breast-fed with formula supplementation, 14 (17.9 percent) had an unsuccessful breast-feeding attempt, and 41 (52.6 percent) did not attempt breast-feeding. Of the 41 patients not attempting to breast-feed, 9 patients did so as a direct consequence of discouragement by a health care professional. Further reasons for feeding with supplementation, having an unsuccessful attempt, and not attempting to breast-feed are presented. Of the 78 women who had children postoperatively, a total of 27 were discouraged from breast-feeding by medical professionals with only 8 of the 27 (29.6 percent) subsequently attempting, despite this recommendation. In comparison, 26 patients were encouraged to breast-feed; nineteen (73.1 percent) of them did subsequently attempt breast-feeding. This rate is statistically significant by using a chi2 test with 1 df(p = 0.0016). Postpartum breast engorgement and lactation was experienced by 31 of the 41 patients not attempting to breast-feed. Of these 31 patients, 19 believed that they would have been able to breast-feed due to the extent of breast engorgement and lactation experienced. Given the use of an inferior flap mammaplasty technique and patient encouragement, the possibility for breast-feeding after reduction mammaplasty exists. This prevalence falls near the breast-feeding rate found in the population not having undergone breast surgery, according to an article in the Canadian Journal of Public Health.

Overexpression of IRS2 in isolated pancreatic islets causes proliferation and protects human beta-cells from hyperglycemia-induced apoptosis.

Studies in vivo indicate that IRS2 plays an important role in maintaining functional beta-cell mass. To investigate if IRS2 autonomously affects beta-cells, we have studied proliferation, apoptosis, and beta-cell function in isolated rat and human islets after overexpression of IRS2 or IRS1. We found that beta-cell proliferation was significantly increased in rat islets overexpressing IRS2 while IRS1 was less effective. Moreover, proliferation of a beta-cell line, INS-1, was decreased after repression of Irs2 expression using RNA oligonucleotides. Overexpression of IRS2 in human islets significantly decreased apoptosis of beta-cells, induced by 33.3 mM D-glucose. However, IRS2 did not protect cultured rat islets against apoptosis in the presence of 0.5 mM palmitic acid. Overexpression of IRS2 in isolated rat islets significantly increased basal and D-glucose-stimulated insulin secretion as determined in perifusion experiments. Therefore, IRS2 is sufficient to induce proliferation in rat islets and to protect human beta-cells from D-glucose-induced apoptosis. In addition, IRS2 can improve beta-cell function. Our results indicate that IRS2 acts autonomously in beta-cells in maintenance and expansion of functional beta-cell mass in vivo.

Incidence of surgical site infections in pediatric patients: a 3-month prospective study in an academic pediatric surgical unit.

During a 3-month period 259 pediatric surgical procedures in 236 patients were followed for the development of surgical site infections (SSI): 17 sites became infected, an overall infection rate of 6.6%. The incidence in our study was therefore higher than expected. As expected, the infection rate increased according to wound contamination: dirty sites had a SSI rate of 30%. Emergency procedures, operation duration over 1 h, and inpatients showed a statistically significant higher risk of developing SSI. Although there were differences between males and females, individual surgeons, and the use of antibiotic prophylaxis, these differences were not statistically significant.

Distribution of heterochromatin on the mitotic chromosomes of Musca domestica L. in relation to the activity of male-determining factors.

In the housefly, male sex is determined by a dominant factor, M, located either on the Y, on the X, or on any of the five autosomes. M factors on autosome I and on fragments of the Y chromosome show incomplete expressivity, whereas M factors on the other autosomes are fully expressive. To test whether these differences might be caused by heterochromatin-dependent position effects, we studied the distribution of heterochromatin on the mitotic chromosomes by C-banding and by fluorescence in situ hybridization of DNA fragments amplified from microdissected mitotic chromosomes. Our results show a correlation between the chromosomal position of M and the strength of its male-determining activity: weakly masculinizing M factors are exclusively located on chromosomes with extensive heterochromatic regions, i.e., on autosome I and on the Y chromosome. The Y is known to contain at least two copies of the M factor, which ensures a strong masculinizing effect despite the heterochromatic environment. The heterochromatic regions of the sex chromosomes consist of repetitive sequences that are unique to the X and the Y, whereas their euchromatic parts contain sequences that are ubiquitously found in the euchromatin of all chromosomes of the complement.

Genetic transformation of the housefly Musca domestica with the lepidopteran derived transposon piggyBac.

The piggyBac transposable element was successfully used for stable genetic transformation of the housefly Musca domestica. The construct contains the EGFP marker under the control of Pax-6 binding sites, which can drive eye-specific expression in insect species as distantly related as Drosophila melanogaster and Tribolium castaneum [Berghammer, A.J., Klingler, M. and Wimmer, E.A. (1999) Nature 402: 370-371]. We obtained seven independent integration events among 41 fertile G0 Musca flies. Most of the transformed lines contained two or more chromosomal insertions of the EGFP marker which were stably inherited over more than 15 generations. piggyBac-mediated transposition was verified by identifying the characteristic TTAA duplication at the insertion sites. This first report of stable transmission of a genetic marker in Musca confirms the use of this vector-marker system for effective gene transfer in a broad range of insect species.

Wound infection after arterial surgical procedures.

During the period October 1983 to March 1987, 603 patients who underwent arterial surgical procedures were studied to determine the incidence and treatment of wound infections. Bypass procedures were performed in 395 patients (65.5%), in which autogenous vein was used for 158 grafts (26%), synthetic Dacron for 216 grafts (36%), and umbilical vein for 21 grafts (3.5%). Thrombo-endarterectomies, embolectomies and patch-grafts were performed in 208 patients (34.5%). An Infection Control Nurse examined and registered the wounds. The definition of wound infection used in our study is equivalent to Szilagyi grade II infection. Vascular surgery is classified as clean surgery, the clean wound infection rate being a useful measurement to evaluate preventative measures and surgical technique. Thirty-one patients (5.1%) developed a wound infection as a postoperative complication. The overall incidence of wound complications including haematoma and seroma following arterial reconstruction was 13%. The site of wound infection was predominantly the groin. The most common pathogen was Staphylococcus aureus which was found in 17 patients (2.8%). All infections resolved without further surgical intervention. The influence of possible aetiological factors is considered and the importance of prophylactic antibiotics and good surgical technique is stressed.