<Emphasis Type="Italic">Daphnia galeata</Emphasis> in the deep hypolimnion: spatial differentiation of a “typical epilimnetic” species

One of the most serious threats to tropical mangrove ecosystems caused by shrimp farming activities is the poor management of pond waste materials. We hypothesise that mangroves can tolerate chemical residues discharged from shrimp farms and can be used as biofilters, but the capability of mangroves to cope with solid sediments dredged from shrimp ponds is limited. Our study in Pak Phanang, Thailand, confirmed that the excess sediments discharged from nearby shrimp ponds reduced mangrove growth rates and increased mortality rates. A series of transformed multi-temporal satellite images was used in combination with the field data to support this claim. In addition, a comparison between four dominant mangrove species revealed that Avicennia marina could tolerate sedimentation rates of >6 cm year⁻¹, while Bruguiera cylindrica tolerated sedimentation rates of 5 cm year⁻¹ (total sediment depth = 25 cm) before dying, while Excoecaria agallocha and Lumnitzera racemosa performed intermediate. This outcome implied that in our situation A. marina and to lesser extent E. agallocha and L. racemosa could be more effective as biofilters than B. cylindrica, as they may survive the sedimentation longer in the disposal areas. Further studies on the impact of sedimentation and chemical pollution of shrimp farm wastes on mangrove mortality and growth are required.     

Design, synthesis, and antimalarial activity of structural chimeras of thiosemicarbazone and ferroquine analogues

The design, synthesis, and antimalarial activity of chimeras of thiosemicarbazones (TSC) and ferroquine (FQ) is reported. Key structural elements derived from FQ were coupled to fragments capable of coordinating metal ions. Biological evaluation was conducted against four strains of the malaria parasite Plasmodium falciparum and against the parasitic cysteine protease falcipain-2. To establish the role of the ferrocenyl moiety in the antiplasmodial activity of this series, purely organic parent compounds were also synthesized and tested. The presence of the aminoquinoline structure, allowing transport of the compounds to the food vacuole of the parasite, seems to be the major contributor to antimalarial activity.     

Occurence of adverse events due to continuous glucose monitoring

Aims: Continuous glucose monitoring (CGM) using transcutaneous sensors is becoming a sophisticated method to control and regulate glucose metabolism. The transcutaneous sensor of the CGM system (CGMStrade mark Medtronic Minimed, Northridge, CA, USA) is chosen to measure glucose concentration in interstitial fluid up to three days after insertion even though its function remains stable for a longer period. The question arises, which factors really limit the period of sensor insertion without unnecessary risk. The aim of this study was to assess any adverse events occurring in the course of 9 days after the sensor insertion. Methods: In a group of 22 healthy volunteers aged 21.8+/-1.30 y (mean +/- SE) a total of 26 sensors was inserted subcutaneously in gluteal or lumbar region for 9 days. Before insertion the site was sprayed with an antiseptic (Cutasept F, Bode Chemie, Hamburg, Germany). Local adverse reactions and disturbances in general condition were examined. Results: In the course of 184 sensor-days, there were only minor local adverse events: hypersensitivity, itching, pain, redness, burning, subcutaneous hemorrhage. Additionally, sleep disturbances, attention deficits, problems related to the CGMS monitor, to adhesive tape and/or sensor were found. None of these resulted in sensor withdrawal. In 12 volunteers (55 %) no complications were observed. The sensor function measured according to electrical signals (ISIG) failed (always on day 1-2) in 4 cases (16 %). Conclusions: The present FDA approved 3-day insertion period for Medtronic transcutaneous sensor does not seem to limit its use and appears to be worth a careful revision.     

Evaluation of bone healing in femurs lengthened via the gradual distraction method

BACKGROUND: Treatment of leg length inequality via lengthening of the shorter extremity is an infrequent orthopedic procedure due to the requirement of special distraction devices and possible serious complications. Essential qualitative changes in operative technique development are associated with the name of G. A. Ilizarov, who paved the way for the autoregenerate gradual distraction method in the 1950s. MATERIAL AND METHODS: In the years 1990 through 2006 a total of 57 patients underwent femur lengthening via gradual distraction using various types of external fixators at the Department of Pediatric Surgery, Orthopedics, and Traumatology, Faculty Hospital in Brno. The quality of bone healing was monitored and a number of parameters followed and statistically evaluated using regularly scheduled X-ray examinations. RESULTS: In 11 cases we had to remove the external fixator following the distraction phase, perform an osteosynthesis via a splint and fill the distraction gap via spongioplasty. The bone healing was satisfactory in the remaining 46 patients and the lengthened bone required no other fixation method. The analysis showed statistically significant deceleration in bone healing following distraction in female patients over 12 years of age, and in boys over 14 years of age. Lack of periosteal callus five weeks after surgery always signified serious problems in further healing. Severe complications were recorded in 11 cases during the distraction phase, and in 9 cases after the removal of the distraction apparatus. CONCLUSIONS: The aim of this report was to present the results of our study of distraction gap bone healing using the gradual lengthening approach.     

Intra-arterial chemotherapy and its significance in the treatment of oropharyngeal carcinoma

BACKGROUND: In complex therapeutic algorithms for cancer, regional intra-arterial chemotherapy is usually used as an adjuvant and placed in the beginning of treatment. Clinical experience however shows that the achieved remission of malignant tumour illness after non-adjuvant chemotherapy is only temporary and short-lived. The illness progresses relatively quickly if the patient receives no further treatment and most clinical studies have not found any significant increase in life expectancy in oncological patients treated with this method. The question remains to what extent the poor results are due to the treatment method and its position in the therapeutic algorithm, and to what extent they are due to imperfect knowledge of molecular tumour genetics or inappropriate choice of the neoadjuvant intra-arterial chemotherapy METHODS: We compared preliminary results of immunohistochemical examinations (detection and analysis of expression of proteins Ku 70, STAT 1,3,5 which take part in the regulation of cell cycle apoptosis and repair of damaged DNA, carried out before and after chemotherapy, suggest that depending on the effects of neoadjuvant intra-arterial chemotherapy and patient's survivance. RESULTS AND CONCLUSION: An overview of intra-arterial neoadjuvant chemotherapy of head and neck is presented. Knowledge of cell cycle processes, especially apoptosis and repair of damaged DNA, could significantly influence the choice of the therapeutic algorithm and therapeutical effect.     

Early onset pauciarticular arthritis is the major risk factor for naproxen-induced pseudoporphyria in juvenile idiopathic arthritis

Pseudoporphyria (PP) is characterized by skin fragility, blistering and scarring in sun-exposed skin areas without abnormalities in porphyrin metabolism. The phenylpropionic acid derivative group of nonsteroidal anti-inflammatory drugs, especially naproxen, is known to cause PP. Naproxen is currently one of the most prescribed drugs in the therapy of juvenile idiopathic arthritis (JIA). The prevalence of PP was determined in a 9-year retrospective study of children with JIA and associated diseases. In addition, we prospectively studied the incidence of PP in 196 patients (127 girls and 69 boys) with JIA and associated diseases treated with naproxen from July 2001 to March 2002. We compared these data with those from a matched control group with JIA and associated diseases not treated with naproxen in order to identify risk factors for development of PP. The incidence of PP in the group of children taking naproxen was 11.4%. PP was particularly frequent in children with the early-onset pauciarticular subtype of JIA (mean age 4.5 years). PP was associated with signs of disease activity, such as reduced haemoglobin (<11.75 g/dl), and increased leucocyte counts (>10,400/μl) and erythocyte sedimentation rate (>26 mm/hour). Comedications, especially chloroquine intake, appeared to be additional risk factors. The mean duration of naproxen therapy before the onset of PP was 18.1 months, and most children with PP developed their lesions within the first 2 years of naproxen treatment. JIA disease activity seems to be a confounding factor for PP. In particular, patients with early-onset pauciarticular JIA patients who have significant inflammation appear to be prone to developing PP upon treatment with naproxen.     

Fluoroanalogues of anti-cytomegalovirus agent cyclopropavir: synthesis and antiviral activity of (E)- and (Z)-9-{[2,2-bis(hydroxymethyl)-3-fluorocyclopropylidene]methyl}-adenines and guanines

Synthesis of fluorinated cyclopropavir analogues 13a, 13b, 14a, and 14b is described starting from alkene 15. Addition of carbene derived from dibromofluoromethane gave bromofluoro cyclopropane 16. Reduction (compound 17) followed by desilylation gave intermediate 18, which was transformed to 2-nitrophenylselenenyl derivative 19. Oxidation to selenoxide 20 was followed by beta-elimination to afford methylenecyclopropane 21. Addition of bromine provided compound 22 for alkylation-elimination of adenine and 2-amino-6-chloropurine. The resultant E,Z isomeric mixtures of methylenecyclopropanes 23a + 24a and 23c + 24c were resolved and the individual isomers were deprotected to give adenine analogues 13a and 14a as well as compounds 13c and 14c. Hydrolytic dechlorination of 13c and 14c furnished guanine analogues 13b and 14b. The only significant antiviral effects were observed with analogue 13a against HCMV and 14a against VZV in cytopathic inhibition assays.     

Overaccumulation of γ-Glutamylcysteine in a Jasmonate-Hypersensitive Arabidopsis Mutant Causes Jasmonate-Dependent Growth Inhibition

Glutathione (GSH) is essential for many aspects of plant biology and is associated with jasmonate signaling in stress responses. We characterized an Arabidopsis (Arabidopsis thaliana) jasmonate-hypersensitive mutant (jah2) with seedling root growth 100-fold more sensitive to inhibition by the hormone jasmonyl-isoleucine than the wild type. Genetic mapping and genome sequencing determined that the mutation is in intron 6 of GLUTATHIONE SYNTHETASE2, encoding the enzyme that converts γ-glutamylcysteine (γ-EC) to GSH. The level of GSH in jah2 was 71% of the wild type, while the phytoalexin-deficient2-1 (pad2-1) mutant, defective in GSH1 and having only 27% of wild-type GSH level, was not jasmonate hypersensitive. Growth defects for jah2, but not pad2, were also seen in plants grown to maturity. Surprisingly, all phenotypes in the jah2 pad2-1 double mutant were weaker than in jah2. Quantification of γ-EC indicated these defects result from hyperaccumulation of this GSH precursor by 294- and 65-fold in jah2 and the double mutant, respectively. γ-EC reportedly partially substitutes for loss of GSH, but growth inhibition seen here was likely not due to an excess of total glutathione plus γ-EC because their sum in jah2 pad2-1 was only 16% greater than in the wild type. Further, the jah2 phenotypes were lost in a jasmonic acid biosynthesis mutant background, indicating the effect of γ-EC is mediated through jasmonate signaling and not as a direct result of perturbed redox status.Glutathione (GSH) is an essential thiol of most higher organisms, including plants. Primarily found in the reduced form, its roles in maintaining a reduced intracellular state are numerous and well characterized (Foyer and Noctor, 2011; Noctor et al., 2011). Additionally, GSH is involved in detoxifying reactive oxygen species, heavy metal detoxification through phytochelatins, elimination of xenobiotics, and signaling of plant development and stress responses (Rouhier et al., 2008).GSH is synthesized in two steps. The first links Cys to the γ-carboxyl group of Glu through an amide bond catalyzed by γ-glutamylcysteine (γ-EC) synthetase, encoded by the single gene GSH1 in Arabidopsis (Arabidopsis thaliana). Gly is then added by GSH synthetase (GSH-S), also encoded by a single gene (GSH2). GSH is typically present at millimolar levels in plants, and although γ-EC is normally present at only a few percent of this amount, there is evidence that γ-EC has redox activities in Arabidopsis (Pasternak et al., 2008).Insertional knockouts of GSH1 are embryo lethal, and rootmeristemless1, with only 5% of wild-type GSH level, lacks a root apical meristem due to cell cycle arrest (Vernoux et al., 2000; Cairns et al., 2006). Other mutants producing 25% to 50% of wild-type GSH levels grow normally but exhibit defects under various stress conditions. For example, phytoalexin-deficient2-1 (pad2-1) and cadmium sensitive2 mutants are susceptible to pathogens and hypersensitive to Cd, respectively, while regulator of axillary meristems1 causes elevated expression of ASCORBATE PEROXIDASE2 under non-photooxidative-stress conditions (Glazebrook and Ausubel, 1994; Cobbett et al., 1998; Ball et al., 2004).GSH2 null alleles (gsh2-1 and gsh2-2) are also lethal, although plants survive to the early seedling stage (Pasternak et al., 2008). Survival past the embryo stage was attributed to partial complementation of GSH activity by γ-EC, which accumulates to excessive levels in gsh2-1, and the mutant is partially rescued by GSH supplementation. Missense and nonsense GSH2 alleles of membrane trafficking mutants (gsh2-3–gsh2-5) disrupt endoplasmic reticulum (ER) organization and also arrest growth in early seedling development, while a weaker allele (gsh2-6) reached maturity but was smaller than the wild type (Au et al., 2012). A screen for reduced response to Cd also yielded a viable missense mutant of GSH2 (nonresponse or reduced response to Cd2) with approximately 75% of the wild-type GSH level (Jobe et al., 2012).Plant oxidative stress responses involve both redox signaling through GSH and jasmonate hormonal signaling, and gene expression studies have clearly linked these two signaling systems. GSH biosynthesis and metabolism genes are induced by jasmonate, while manipulating GSH level or redox status in various mutants alters expression of genes for jasmonate biosynthesis and signaling (Xiang and Oliver, 1998; Mhamdi et al., 2010; Han et al., 2013). GSH and jasmonate are also associated with protective glucosinolate production in response to insect feeding (Noctor et al., 2011). For example, pad2-1 is deficient in glucosinolates and more susceptible to insects, while several studies have shown jasmonate induces glucosinolates (Brader et al., 2001; Mikkelsen et al., 2003; Sasaki-Sekimoto et al., 2005; Schlaeppi et al., 2008). Liu et al. (2010) isolated jasmonic acid hypersensitive1 (jah1), an Arabidopsis mutant with greater inhibition of root growth than the wild type in the presence of jasmonic acid (JA). The affected gene encodes a cytochrome P450 (CYP82C3) involved in indole glucosinolate production, and this mutant was more susceptible to Botrytis cinerea.The basic mechanism of jasmonate signal transduction and some of the downstream responses emanating from it are now well understood (Browse, 2009; Wasternack and Hause, 2013). However, the mechanisms by which jasmonate and GSH coordinate their activities to mediate oxidative stress and other responses are not known. This study characterized, to our knowledge, a new jasmonate-hypersensitive mutant that accumulates excess γ-EC due to a defect in GSH2, but GSH is only modestly reduced. Results show that elevated γ-EC is deleterious to plant growth through a jasmonate-dependent mechanism.