Robot-assisted TAMIS: a systematic review of feasibility and outcomes.

BACKGROUND: In the advancement of transanal local excision, robot-assisted transanal minimal invasive surgery is the newest development. In the confined area of the rectum, robot-assisted surgery should, theoretically, be superior due to articulated utensils, video enhancement, and tremor reduction, however, this has not yet been investigated. The aim of this study was to review the evidence reported to-date on experience of using robot-assisted transanal minimal invasive surgery for treatment of rectal neoplasms. METHODS: A comprehensive literature search of Embase and PubMed from May to August 2021were performed. Studies including patients diagnosed with rectal neoplasia or benign polyps who underwent robot-assisted transanal minimal invasive surgery were included. All studies were assessed for risk of bias through assessment tools. Main outcome measures were feasibility, excision quality, and complications. RESULTS: Twenty-five studies with a total of 322 local excisions were included. The studies included were all retrospective, primarily case-reports, -series, and cohort studies. The median distance from the anal verge ranged from 3.5 to 10 cm and the median size was between 2.5 and 5.3 cm. Overall, 4.6% of the resections had a positive resection margin. The overall complication rate was at 9.5% with severe complications (Clavien-Dindo score III) at 0.9%. CONCLUSION: Based on limited, retrospective data, with a high risk of bias, robot-assisted transanal minimal invasive surgery seems feasible and safe for local excisions in the rectum.

The effect of alkylation on the micro-solvation of ethers revealed by highly localized water librational motion.

The specific far-infrared spectral signatures associated with highly localized large-amplitude out-of-plane librational motion of water molecules have recently been demonstrated to provide sensitive spectroscopic probes for the micro-solvation of organic molecules [Mihrin et al., Phys. Chem. Chem. Phys. 21(4), 1717 (2019)]. The present work employs this direct far-infrared spectroscopic approach to investigate the non-covalent intermolecular forces involved in the micro-solvation of a selection of seven ether molecules with systematically varied alkyl substituents: dimethyl ether, diethyl ether, diisopropyl ether, ethyl methyl ether, t-butyl methyl ether, and t-butyl ethyl ether. The ranking of the observed out-of-plane water librational band signatures for this selected series of ether-water complexes embedded in inert neon matrices at 4 K reveals information about the interplay of directional intermolecular hydrogen bond motifs and non-directional and long-range dispersion interactions for the micro-solvated structures. These far-infrared observables differentiate minor subtle effects introduced by specific alkyl substituents and serve as rigorous experimental benchmarks for modern quantum chemical methodologies of various levels of scalability, which often fail to accurately predict the structural variations and corresponding vibrational signatures of the closely related systems. The accurate interaction energies of the series of ether-water complexes have been predicted by the domain based local pair natural orbital coupled cluster theory with single-, double-, and perturbative triple excitations, followed by a local energy decomposition analysis of the energy components. In some cases, the secondary dispersion forces are in direct competition with the primary intermolecular hydrogen bonds as witnessed by the specific out-of-plane librational signatures.

High-Resolution Infrared Synchrotron Investigation of (HCN)2 and a Semi-Experimental Determination of the Dissociation Energy D0.

The high-resolution infrared absorption spectrum of the donor bending fundamental band ν 61 of the homodimer (HCN)2 has been collected by long-path static gas-phase Fourier transform spectroscopy at 207 K employing the highly brilliant 2.75 GeV electron storage ring source at Synchrotron SOLEIL. The rovibrational structure of the ν 61 transition has the typical appearance of a perpendicular type band associated with a Σ-Π transition for a linear polyatomic molecule. The total number of 100 assigned transitions are fitted employing a standard semi-rigid linear molecule Hamiltonian, providing the band origin ν0 of 779.05182(50) cm-1 together with spectroscopic parameters for the degenerate excited state. This band origin, blue-shifted by 67.15 cm-1 relative to the HCN monomer, provides the final significant contribution to the change of intra-molecular vibrational zero-point energy upon HCN dimerization. The combination with the vibrational zero-point energy contribution determined recently for the class of large-amplitude inter-molecular fundamental transitions then enables a complete determination of the total change of vibrational zero-point energy of 3.35±0.30 kJ mol-1 . The new spectroscopic findings together with previously reported benchmark CCSDT(Q)/CBS electronic energies [Hoobler et al. ChemPhysChem. 19, 3257-3265 (2018)] provide the best semi-experimental estimate of 16.48±0.30 kJ mol-1 for the dissociation energy D0 of this prototypical homodimer.

Highly localized H2O librational motion as a far-infrared spectroscopic probe for microsolvation of organic molecules.

The most prominent spectroscopic observable for the hydrogen bonding between individual molecules in liquid water is the broad absorption band detected in the spectral region between 300 and 900 cm-1. The present work demonstrates how the associated large-amplitude out-of-plane OH librational motion of H2O molecules also directly reflects the microsolvation of organic compounds. This highly localized OH librational motion of the first solvating H2O molecule causes a significant change of dipole moment and gives rise to a strong characteristic band in the far-infrared spectral region, which is correlated quantitatively with the complexation energy. The out-of-plane OH librational band origins ranging from 324.5 to 658.9 cm-1 have been assigned experimentally for a series of four binary hydrogen-bonded H2O complexes embedded in solid neon involving S-, O- and N-containing compounds with increasing hydrogen bond acceptor capability. The hydrogen bond energies for altogether eight binary H2O complexes relative to the experimental value of 13.2 ± 0.12 kJ mol-1 for the prototypical (H2O)2 system [Rocher-Casterline et al., J. Chem. Phys., 2011, 134, 211101] are revealed directly by these far-infrared spectroscopic observables. The far-infrared spectral signatures are able to capture even minor differences in the hydrogen bond acceptor capability of O atoms with slightly different alkyl substituents in the order H-O-C(CH3)3 > CH3-O-CH3 > H-O-CH(CH3)2 > H-O-CH2CH3.

Experiences of being diagnosed with osteoporosis: a meta-synthesis.

This systematic review provides synthesised knowledge and guidance to health professionals on the experiences and perspectives of being diagnosed with osteoporosis from the patient's point of view. Using individuals' experiences and meanings can promote tailored and targeted information and guidance on osteoporosis, bone care and treatment at different stages of the osteoporosis trajectory. INTRODUCTION: To be diagnosed with osteoporosis with or without fragility fractures affects individuals differently. The aim of this review was firstly to aggregate existing qualitative evidence regarding an individual's experience of being diagnosed with osteoporosis at different stages, and secondly, to use a systematic approach to develop a conceptual understanding of central issues relevant for health professionals in order to provide support and guidance to patients/individuals. METHODS: This study used a systematic review methodology and methods for qualitative synthesis as recommended by Cochrane and integrated the findings of qualitative research from eight databases (Medline, PubMed, CINAHL, Embase, SweMed+, PsycINFO, ERIC, Web of Science) to July 2016. Selection and assessment were performed by three authors while four authors were involved in the analysis. Findings were cross-checked with the original article to ensure consistency with the individual's accounts. RESULTS: Our findings have revealed that individuals diagnosed with osteoporosis do not perceive osteoporosis as a biomedical trajectory but as a self-perceived continuum of severity and health. To be diagnosed with osteoporosis affects individuals differently depending on, for example, personal experience, pre-conceived notions of or knowledge about the disease, fragility fractures or pain. Hence, individuals will create a meaning of the diagnosis based on self-perceived fracture risk, self-perceived severity of osteoporosis and at the same time, self-perceived health. CONCLUSIONS: This meta-synthesis provides knowledge for health professionals on the experiences and perspectives of being diagnosed with osteoporosis from the patient's point of view. The experience, meaning and significance of osteoporosis must be taken into consideration and can be used to promote tailored and targeted information and guidance on osteoporosis, bone care and treatment at different stages of the osteoporosis trajectory.

High-resolution synchrotron terahertz investigation of the large-amplitude hydrogen bond librational band of (HCN)2.

The high-resolution terahertz absorption spectrum of the large-amplitude intermolecular donor librational band ν of the homodimer (HCN)2 has been recorded by means of long-path static gas-phase Fourier transform spectroscopy at 207 K employing a highly brilliant electron storage ring source. The rovibrational structure of the ν band has the typical appearance of a perpendicular type band of a Σ-Π transition for a linear polyatomic molecule. The generated terahertz spectrum is analyzed employing a standard semi-rigid linear molecule Hamiltonian, yielding a band origin ν0 of 119.11526(60) cm-1 together with values for the excited state rotational constant B', the excited state quartic centrifugal distortion constant DJ' and the l-type doubling constant q for the degenerate state associated with the ν mode. The until now missing donor librational band origin enables the determination of an accurate experimental value for the vibrational zero-point energy of 2.50 ± 0.05 kJ mol-1 arising from the entire class of large-amplitude intermolecular modes. The spectroscopic findings are complemented by CCSD(T)-F12b/aug-cc-pV5Z (electronic energies) and CCSD(T)-F12b/aug-cc-pVQZ (force fields) electronic structure calculations, providing a (semi)-experimental value of 17.20 ± 0.20 kJ mol-1 for the dissociation energy D0 of this strictly linear weak intermolecular CHN hydrogen bond.

Cardiac vagal tone, a non-invasive measure of parasympathetic tone, is a clinically relevant tool in Type 1 diabetes mellitus.

AIMS: To compare a novel index of parasympathetic tone, cardiac vagal tone, with established autonomic variables and to test the hypotheses that (1) cardiac vagal tone would be associated with established time and frequency domain measures of heart rate and (2) cardiac vagal tone would be lower in people with Type 1 diabetes than in a matched healthy cohort and lower still in people with established neuropathy. METHODS: Cardiac vagal tone is a validated cardiometrically derived index of parasympathetic tone. It is measured using a standard three-lead electrocardiogram which connects, via Bluetooth, to a smartphone application. A 5-min resting recording of cardiac vagal tone was undertaken and observational comparisons were made between 42 people with Type 1 diabetes and peripheral neuropathy and 23 without peripheral neuropathy and 65 healthy people. In those with neuropathy, 24-h heart rate variability values were compared with cardiac vagal tone. Correlations between cardiac vagal tone and clinical variables were also made. RESULTS: Cardiac vagal tone was lower in people with established neuropathy and Type 1 diabetes in comparison with healthy participants [median (interquartile range) linear vagal scale 3.4 (1.6-5.5 vs 7.0 (5.5-9.6); P < 0.0001]. Cardiac vagal tone was positively associated with time (r = 0.8, P < 0.0001) and frequency domain markers of heart rate variability (r = 0.75, P < 0.0001), representing established measures of parasympathetic function. Cardiac vagal tone was negatively associated with age (r=-0.32, P = 0.003), disease duration (r=-0.43, P < 0.0001) and cardiovascular risk score (r=-0.32, P = 0.006). CONCLUSIONS: Cardiac vagal tone represents a convenient, clinically relevant method of assessing parasympathetic nervous system tone, potentially facilitating the earlier identification of people with Type 1 diabetes who should undergo formal autonomic function testing.

Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens).

Male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby Gobiusculus flavescens (Fabricius) was investigated in relation to time in reproductive season and individual physical parameters. This small teleost fish is most likely the most abundant species found along the rocky shores of the North East Atlantic. The two-spotted goby has a single reproductive season, during which nest-caring males can raise several clutches of offspring. According to the literature the males are on average larger than the females. Here we report for the first time a population showing a reversal of this trend, with males on average being smaller than females, a difference likely caused by a large proportion of small males. Early in the breeding season these small males have typical sneaker characters, with relatively large testes and small seminal duct glands compared to the larger dominant territorial males. The presence of these two alternative male reproductive tactics is confirmed by histological studies, which shows the presence of sperm in the sperm duct glands (SDG) of smaller males, but not in the SDG of intermediate and larger males. To our knowledge, males with typical sneaker characters have not been reported in earlier studied populations of two-spotted goby. Interestingly we found that testes investment declined significantly over the course of the breeding season, and that this reduction was significantly more pronounced in small compared to the large males. Further, a significant increase in seminal duct gland (SDG) mass was observed for the smaller males over the breeding season. We propose that this indicates a possible shift in mating tactic by smaller males from a parasitic to a nest-holding tactic over the course of the breeding season. Thus, the observed size dependent plasticity in investment in SDG over time suggests that the reproductive tactic of G. flavescens is conditional, and possibly influenced by mate availability and male--male competition.

The single-dose pharmacokinetics of alitretinoin and its metabolites are not significantly altered in patients with cirrhosis.

BACKGROUND: Alitretinoin (9-cis-retinoic acid, Toctino(®) ) has been marketed recently for oral therapy for chronic hyperkeratotic hand eczema. As alitretinoin is highly lipophilic and metabolized mainly in the liver, it is currently considered to be contraindicated in patients with liver disease. However, the pharmacokinetics and metabolism of alitretinoin have not been studied in these patients. OBJECTIVES: To study the single-dose pharmacokinetics and metabolism of alitretinoin and its metabolites in patients with cirrhosis following oral administration. METHODS: Eight patients with cirrhosis and eight matched volunteer healthy controls were given a single 30-mg oral dose of alitretinoin. Blood and urine samples were collected during the following 24-h study period. Samples were analysed for alitretinoin and for known metabolites using reverse-phase high-performance liquid chromatography. The pharmacokinetics were then evaluated using standard noncompartmental models. RESULTS: No significant differences were found between healthy controls and patients with cirrhosis when analysing the pharmacokinetic parameters of alitretinoin and its metabolites. Thus, the mean half-lives of alitretinoin were 5·3 and 5·6 h (P = 0.733) and the oral clearances were 1·92 and 1·39 L h(-1) kg(-1) (P = 0·243) in the patient group and the healthy control group, respectively. CONCLUSIONS: The metabolism and pharmacokinetics of alitretinoin following oral administration of the recommended dose of 30 mg for the treatment of severe hand eczema were similar in patients with cirrhosis and in healthy controls. If indicated, alitretinoin can be used in these patients with careful and close monitoring.

Automated high precision secondary pH measurements.

A new setup for high precision, automated secondary pH measurements together with a reference measurement procedure has been developed and tested in interlaboratory comparisons using buffers pH 4.005, pH 7.000, and pH 10.012 at 25 °C and 37 °C. Using primary buffers as standards, a standard uncertainty in pH better than 0.005 can be reached. The central measuring device is a one piece, thermostatted cell of PFA (perfluoroalkoxy) with a built-in Hamilton(®) Single Pore™ Glass electrode. Due to its flow-through principle this device allows pH measurements with low consumption of measurement solutions. The very hydrophobic and smooth PFA as construction material facilitates complete emptying of the cell. Furthermore, the tempering unit affords very precise temperature control and hence contributes to the low target uncertainty of the produced secondary buffer solutions. Use of a symmetric measurement sequence and the two point calibration was sufficient to reach high precision and accuracy.

The protection afforded by the outer layer to procercoids of Schistocephalus solidus during passage through the stomach lumen of their vertebrate host (Gasterosteus aculeatus).

Intestinal cestodes with complex life cycles have to pass through the acid stomach lumen of their vertebrate host(s) in order to reach their preferred site of development. The cestode's tegument is the only organ in constant contact with this hostile environment. Procercoids of Schistocephalus solidus (order Diphyllobothriidea) lose their outer layer on passing through the acidic stomach of their second intermediate host (Gasterosteus aculeatus). We wanted to investigate if the outer layer is an adaptation that enables passage through this hostile environment. We used fish bile to force the procercoid larvae to shed their outer layer. This allowed us to compare the survival of the normal procercoids and the transformed ones when exposed to hydrochloric acid. We observed that the presence of the outer layer significantly improved the survival and active period of the procercoid larvae. Thus we conclude that in cestodes which inhabit the digestive tracts of vertebrates, the outer layer is an adaptation which enables them to pass through the acidic stomach environment of their vertebrate host(s).

In vitro transition of Schistocephalus solidus (Cestoda) from coracidium to procercoid and from procercoid to plerocercoid.

With the present study, a culture system for successive life-cycle stages of the tapeworm Schistocephalus solidus was developed and this report documents for the first time, cultivation of the procercoid stage of S. solidus from eggs. Additionally we have transformed procercoids dissected from experimentally infected copepods and cultured procercoids into the early plerocercoid stage in vitro. Observations in the culture suggest that the coracidia can interact with their external environment and need no host specific stimuli, except for the components in the culture medium, for activation and hatching from the embryophore. Increasing the culture medium pH from 7.3 to 8.0 improved escape rates and frequencies of hook contractions, suggesting that the oncosphere may recognize and respond to environmental conditions along the host intestine. Procercoids in the culture did not stop growing indicating that conditions within the copepod may be important to limit growth and to induce transformation to plerocercoids. When procercoids are dissected from copepods and transferred to the culture, the outer tegument layers and cercomer starts to loosen. Comparison of the lectin staining of the loosened outer tegument layers and cercomer in procercoids dissected from copepods confirms that transitions of both, the oncosphere to procercoid and procercoid to plerocercoids, has taken place in the in vitro cultures.

The metabolism and pharmacokinetics of isotretinoin in patients with acne and rosacea are not influenced by ethanol.

BACKGROUND: Isotretinoin is effective in the treatment of severe acne and rosacea. Both parent drug and its main metabolite 4-oxo-isotretinoin are potentially teratogenic compounds and contain a carboxylic acid moiety. In the presence of ethanol, naturally occurring as well as synthetic retinoids also containing a carboxylic acid moiety are capable of undergoing an ethyl esterification with the metabolic formation of more lipophilic compounds with a much longer terminal half-life. OBJECTIVES: To determine if isotretinoin (13-cis-RA), its main metabolite 4-oxo-isotretinoin (4-oxo-13-cis-RA), and other possible metabolites in the presence or absence of ethanol are converted to their corresponding ethyl derivatives in patients with severe acne or rosacea after multiple isotretinoin dosing. In addition, pharmacokinetic parameters of the parent drug and its 4-oxo metabolite were determined. PATIENTS/METHODS: Eleven patients with severe acne or rosacea were treated with isotretinoin daily for 3 months and investigated pharmacokinetically during 24 h after 1 month of treatment and for up to 28 days after discontinuation of therapy. A possible influence of ethanol was evaluated using a simple self-administered questionnaire and by measuring serum ethanol levels during treatment. The concentrations of isotretinoin, 4-oxo-isotretinoin and possible ethylated and nonethylated metabolites were measured by reverse-phase high-performance liquid chromatography. RESULTS: Although seven of 11 patients had a considerable weekly alcohol intake, no endogenous synthesis of ethyl derivatives of isotretinoin, the main 4-oxo metabolite or the all-trans compounds was chromatographically detectable in any of the patients' plasma samples during the treatment period. Multiple dose pharmacokinetic data for the parent drug and its main metabolite were comparable to previous studies. CONCLUSIONS: The metabolism and pharmacokinetics of isotretinoin and its main metabolites are not influenced by ethanol during long-term isotretinoin treatment. After ceasing long-term isotretinoin therapy the recommended period of 1 month for using anticonceptive measures in fertile women seems adequate.

Local and systemic effects of endoluminal pelvic perfusion of isoproterenol: a dose response investigation in pigs.

PURPOSE: Isoproterenol (Sygehus Apotekerne Danmark, Copenhagen, Denmark) is a beta-adrenergic agonist known to cause upper urinary tract relaxation. We studied the local effect on pelvic pressure and the systemic effects of endoluminal perfusion with isoproterenol in a porcine model. MATERIALS AND METHODS: Pigs weighing 40 kg were studied. Catheters were placed in the renal pelvis for pressure measurement and perfusion, and a catheter was used to drain the bladder. Blood pressure and heart rate were recorded. In 6 pigs in group 1 the pelvic pressure increase was examined at increasing flow rates of 0, 2, 5, 8, 10 and 15 ml per minute with saline containing 0, 10(-3), 10(-2), 10(-1), 1 and 10 microg/ml isoproterenol. Blood values of isoproterenol were analyzed. In 6 pigs in group 2 the pelvis was perfused at a flow rate of 8 ml per minute with saline containing 0, 10(-5), 10(-4), 10(-3), 10(-2), 10(-1), 1 and 10 microg/ml isoproterenol. RESULTS: In group 1 endoluminal perfusion with isoproterenol inhibited the pelvic pressure increase due to perfusion at all concentrations of isoproterenol. At a perfusion rate of 8 ml per minute the maximal effect (a 78% decrease) was achieved using 0.1 microg/ml isoproterenol without cardiovascular side effects. In group 2 all isoproterenol concentrations caused significant inhibition of the pressure-flow relationship in a dose dependent matter. A 64% decrease in the pressure increase due to saline perfusion was achieved at 0.1 microg/ml isoproterenol without concomitant significant cardiovascular side effects. Isoproterenol was only detected in plasma during perfusion with 1 and 10 microg/ml isoproterenol, which caused significant cardiovascular side effects in the latter case. CONCLUSIONS: Isoproterenol significantly inhibits the pressure increase due to perfusion in the normal porcine renal pelvis without concomitant cardiovascular side effects. Isoproterenol is a safe drug in this porcine model and, hence, it is potentially useful during endourological procedures.

Human intestinal P-glycoprotein activity estimated by the model substrate digoxin.

OBJECTIVE: P-glycoprotein (Pgp) plays a part in the intestinal uptake of xenobiotics and has been associated with susceptibility to ulcerative colitis. The aim of this study was to examine Pgp activity in relation to age, gender, medical treatment (rifampicin or ketoconazole) and the multidrug resistance (MDR1) gene single nucleotide polymorphisms (SNPs) G2677T and C3435T using the model drug digoxin. MATERIAL AND METHODS: Pgp activity was estimated from the pharmacokinetics of orally administered digoxin in blood samples from 32 healthy subjects. MDR1 gene expression in duodenal biopsies was monitored by real-time quantitative RT-PCR (RQ-PCR) and Western blot analyses. MDR1 SNPs were determined by PCR-restriction fragment length polymorphism (PCR-RFLP). The effect of medical treatment was tested by open, randomized, cross-over treatment with rifampicin and ketoconazole. RESULTS: Rifampicin treatment resulted in increased Pgp activity, duodenal MDR1 mRNA expression and Pgp detection compared with that in the control group (p<0.05 for all), Pgp activity being associated with duodenal MDR1 mRNA level (p<0.05). Individuals homozygous for the 3435 wild-type allele (CC) showed higher Pgp activity (p<0.05), whereas SNP 2677 apparently did not affect Pgp activity. No variation in Pgp in relation to age or gender was found. CONCLUSIONS: Our data confirm that rifampicin increases Pgp activity, by increasing MDR1 mRNA and Pgp levels. Moreover, we found that the wild-type allele of the synonymous polymorphism of MDR1 position 3435 confers a higher Pgp activity. These data support other findings suggesting an effect of Pgp on treatment response and disease susceptibility.

Effect of the oral hypoglycaemic sulphonylurea glibenclamide, a blocker of ATP-sensitive potassium channels, on walking distance in patients with intermittent claudication.

AIMS: The oral hypoglycaemic sulphonylurea glibenclamide stimulates endogenous insulin secretion through blockade of ATP-sensitive potassium (KATP) channels on pancreatic beta cells, but also blocks cardiovascular KATP channels, leading to increased peripheral vascular resistance and reduced peripheral blood flow in non-diabetic subjects. Therefore, this study examined whether a single oral dose of glibenclamide adversely affected the pain-free or maximal walking distance in patients with intermittent claudication. METHODS: In a double-blind, randomized crossover study, 12 non-diabetic patients with intermittent claudication were given a single oral dose of glibenclamide (5.25 mg) or placebo separated by a washout period of 1 week. A treadmill test was carried out 180 min after glibenclamide/placebo intake for determination of pain-free and maximal walking distance. Plasma glucose concentrations were kept constant by an euglycemic clamp. Changes in ankle/brachial blood pressure index (ABI), serum insulin, and serum glibenclamide were also assessed. RESULTS: The pain-free walking distance was 62.8 +/- 9.8 metres (mean +/- sem) after glibenclamide and 52.6 +/- 5.9 metres after placebo (P = 0.52). The maximal walking distance was 142.7 +/- 18.7 metres after glibenclamide and 132.6 +/- 16.6 metres after placebo (P = 0.23). The ABI was not significantly changed by glibenclamide compared with placebo. Serum glibenclamide was 0.51 +/- 0.08 microm 180 min after administration of the drug. Glibenclamide produced an 8-fold increase in circulating insulin compared with placebo (P < 0.001). CONCLUSIONS: Glibenclamide given as a single oral dose commonly used in glucose-lowering drug therapy does not reduce pain-free or maximal walking distance in non-diabetic patients with intermittent claudication.

Diversity of Plasmodium falciparum clones infecting children living in a holoendemic area in north-eastern Tanzania.

The diversity of Plasmodium falciparum clones and their role in progression from asymptomatic to symptomatic condition in children have been investigated. Attempts to identify whether particular parasite genotypes were associated with the development of clinical symptoms have been made. A cohort of 34 initially asymptomatic parasitaemic children aged 1-5 years were followed daily for 31 days. Clinical examinations were made each day for signs and symptoms of clinical malaria, followed by parasitological investigation. Nineteen children developed symptoms suggestive of clinical malaria during this period. Daily blood parasite samples from 13 children who developed clinical malaria symptoms and 7 who remained asymptomatic were genotyped by PCR-amplification of the polymorphic regions of the merozoite surface proteins 1 and 2 (MSP1 and MSP2) and the glutamate rich protein (GLURP) genes. Infections were found to be highly complex in both groups of children. Every isolate examined from both groups had a mixture of parasite clones. Daily changes were observed in both parasite density and genotypic pattern. The mean number of genotypes per individual was estimated at 4.9 and 2.7 for asymptomatic and symptomatic groups of children, respectively. Analysis of allele frequency distributions showed that these differed significantly for the MSP1 locus only.

Selection pressure towards monoxeny in Camallanus cotti (Nematoda, Camallanidac) facing an intermediate host bottleneck situation.

This paper describes the ability of the Asian fish nematode Camallanus cotti to carry out both heteroxeny, i.e. an indirect life-cycle using copepods as intermediate host, and monoxeny, i.e. direct infection and development in the definitive fish host. C. cotti occurs naturally in various freshwater teleosts in Asia. During the past decades it has been disseminated into closed or semi-closed aquaculture systems and aquaria around the world, mainly due to the ornamental fish trade. Under such conditions the species may frequently face a bottleneck situation with regard to the availability of copepods. It is known that C. cotti may reproduce and persist in copepod-free aquaria for several months. In order to investigate whether C. cotti has selected towards monoxeny in water systems lacking copepods, in contrast to the opposite selection pressure when copepods are present, 2 separate infection trials were run. It was shown that the parasite can infect the fish host both indirectly via copepods, and directly. However, C. cotti has significantly higher fitness, expressed as survival to maturity, when transmitted indirectly compared to the direct transmission mode. We suggest that the ability of aquarium populations of C. cotti to carry out a direct life-cycle is favoured by selection in order to avoid extinction whenever copepods are absent. It still remains unknown, however, whether the parasite shows the same characteristics in the wild.

Identification of two novel and potent competitive inhibitors of the glucose-6-phosphatase catalytic protein.

AIM: In this study, we show that inhibitors of the glucose-6-phosphatase (G-6-Pase) catalytic protein could be an alternative approach to the recent G-6-Pase T1-translocase inhibitors to target this enzyme for the treatment of type 2 diabetes. METHOD: The active enantiomers of 4-methoxyphenyl-[4-(4-methoxyphenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridin-5-yl]methanone (Compound A-1) and 4-methoxyphenyl-[4-(4-trifluoromethoxyphenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridin-5-yl]methanone (Compound B-1) were characterized as inhibitors of the G-6-Pase catalytic protein using pig and rat liver microsomes and cultured rat hepatocytes. RESULTS: Both compounds were found to be potent competitive inhibitors of the G-6-Pase catalytic protein obtained from pig and rat liver microsomes. The K(i) values (microM) were calculated to be 0.61 +/- 0.02 and 0.63 +/- 0.08 for compound A-1 and B-1 on intact pig microsomes, and 0.27 +/- 0.02 and 0.29 +/- 0.06 on disrupted pig microsomes. The corresponding values for rat liver microsomes were found to be 3.3 +/- 0.6 and 4.0 +/- 1.2 for compound A-1 and B-1 on intact microsomes, and 1.54 +/- 0.1 and 1.21 +/- 0.1 on disrupted microsomes. Compound A-1 was also able to inhibit pyrophosphatase activities from both intact and disrupted microsomes with equal potency (IC50; 0.43-0.55 microm). Using cultured rat hepatocytes and glycerol as the substrate, these compounds were able to prevent glucose production up to 60% with a concomitant increase in the G-6-P content (2.3-fold) using compound A-1. No increase in glycogen levels was seen. CONCLUSION: These data demonstrated that these compounds were more potent inhibitors on G-6-Pase obtained from pig microsomes and were able to penetrate the microsomal membrane. The hepatocyte data further support the kinetic data, and are also consistent with the evoked mechanism of action.

Distinguishing Plasmodium falciparum treatment failures from re-infections by using polymerase chain reaction genotyping in a holoendemic area in northeastern Tanzania.

An in vivo drug sensitivity study was conducted in Magoda village in northeastern Tanzania to evaluate the usefulness of polymerase chain reaction (PCR)-based genotyping of Plasmodium falciparum parasites to distinguish between re-infection and treatment failure. The study tested P. falciparum susceptibility to a combination of sulfadoxine/pyrimethamine (Fansidar; F. Hoffmann La Roche, Basel, Switzerland). Blood samples were collected before treatment and on days 7, 14, or 28 post-treatment in 51 asymptomatic children, of which 26 could not clear parasitemia within seven days post-treatment. Among the remaining 25 children who had no detectable parasites on day 7, only five remained parasite negative up to day 28. Primary and recrudescent P. falciparum parasites were analyzed by PCR using family specific primers for merozoite surface protein-1 (MSP-1), MSP-2, and glutamate-rich protein (GLURP). All samples contained multiple P. falciparum infections. For all children with recrudescent P. falciparum, common alleles were detected in both the primary and recrudescent samples. However, in no child were the exact same alleles detected in both samples, indicating that probably at least some of the recrudescing parasites originated from new infections. The study demonstrates the general usefulness of PCR genotyping technique in distinguishing re-infections from true recrudescences following therapeutic drug treatment.