Maximum growth rate,size and commonness in a community of bactivorous ciliates

Summary Adaptions which confer competitive ability or resistance to predation are thought to be evolved with a resultant loss in intrinsic rate of increase (r _m). Therefore species which are opportunistic should retain high values of r _m, whereas competitively superior species which employ a strategy of persistance will have low values of r _m. Whether a ciliate species is slow or fast-growing can be judged by comparison with the empirically derived equation relating growth rate and size given by Fenchel (1968).This hypothesis was tested on a group of eleven species of bactivorous ciliates inhabiting a small pond. Species' measured and predicted r _m'S were compared with their commonness in the field. The prediction that species with high values of would be less common, as measured by the number of samples in which they are found, was satisfied by the data. The implications of the data for the ciliate community studied and the potential of as a predictor of ecological characteristics of species are discussed.     

Identification of complement C3f‐desArg and its derivative for acute leukemia diagnosis and minimal residual disease assessment

Therapeutic conditions for acute leukemia (AL) mainly rely on diagnosis and detection of minimal residual disease (MRD). However, no serum biomarker has been available for clinicians to make diagnosis of AL and assessment of MRD. In this study, we performed bead fractionation/MALDI‐TOF‐MS analysis on sera from patients with AL. Support vector machine algorithm was used to obtain diagnostic model that discriminated proteomic spectra of patients with AL from that of controls. Twenty‐six features with p<0.00001 had optimal discriminatory performance, with 97% sensitivity and 100% specificity. Statistical analysis revealed that two peptides with m/z 1778 and 1865 were gradually decreased in their relative intensities with increase of remission degree. Moreover, the peptide with m/z 1865 was also found to be correlated with AL types. With FT‐ICR‐MS detection, both the peptides were identified as fragments of complement C3f. Linear regression analysis showed that the combined use of them could discriminate PML/RARα positive M3 from molecular remission M3. Two fragments of complement C3f were significantly correlated with MRD levels and could be used for clinical practice in MRD assessment.     

Between-group differences in the Iberian dung beetle species-area relationship (Coleoptera: Scarabaeidae)

Between-group α- and β-diversity differences were derived from species-area relationships fitted to field data. The accuracy of spatial richness variation predictions based on area size was also checked. The log-log model (log S = c + z log A) was found to be the best-fit linear model, with slopes (z) ranging from 0.089 to 0.142. Between-group comparisons of z (slope) and q (intercept) parameters, using the S = q + cA^z curvilinear regression model, corroborated early results, indicating a lower β-diversity (slope) for Scarabaeinae than for Geotrupinae and Aphodiinae. The latter group, probably more sensitive to environmental heterogeneity, should contribute more to species richness in large areas. α-Diversity is greater for Aphodiinae, more relevant to local diversity (1 km²), than for Scarabaeinae and considerably greater for these two groups than for Geotrupinae. As earlier results show that the richness of a single dung pat is rather more a function of the Scarabaeinae species pool, richness on dung pat scales is probably due more to the between-dropping mobile Scarabaeinae, while Aphodiinae contribute mainly to local and regional pool richness. Nearly 88 % of the total richness variance is explained by area size. This percentage decreases to 37 % when the spatial structure of area size and species number are extracted. The corresponding figures for Scarabaeinae, Aphodiinae and Geotrupinae are 44, 22 and 31 %, respectively.     

Which Metric of Relative Weight Best Captures Body Fatness in Children?

Objective: To evaluate the relative merits of BMI (kilograms per meter squared) and age‐ and gender‐adjusted BMI, age‐ and gender‐specific z score of BMI, and age‐ and gender‐specific percentiles of BMI as surrogate measures of body fatness among a sample of youth. Research Methods and Procedures: The sample comprised 596 children and adolescents 5 to 18.7 years old and was 40% male and 55% white. Height and weight were measured by trained research staff. DXA was used to determine body fat mass. BMI, age‐ and gender‐specific percentile of BMI, and age‐ and gender‐specific z scores of BMI were computed, and these metrics were compared with measured body fatness. Results: The BMI values in the sample ranged from 12.9 to 55.0 kg/m², with a mean of 24.9 kg/m². The Spearman correlations with percentage body fat were similar for all of the BMI metrics (r = 0.82 to 0.88). Linear regression models with age‐ and gender‐specific percentiles of BMI explained significantly less of the variance (65%) than models with log‐transformed BMI (81%) or age‐ and gender‐specific z scores of BMI (75% to 79%). z scores were the most accurate at classifying children who were overfat (sensitivity = 0.84, specificity = 0.96 for z score ≥1). However, using a BMI ≥85th percentile or a BMI ≥20 kg/m² was also accurate at classifying youth. Discussion: The BMI metrics had similar correlations with body fatness, but age‐ and gender‐specific percentiles of BMI were the least accurate proxy measure of body fatness. However, a BMI z score ≥1, BMI percentile ≥85, and BMI ≥20 kg/m² are all useful for identifying children who may be overfat.     

Oxygen controlled batch cultivations of Schizophyllum commune for enhanced production of branched β-1,3-glucans

Oxygen and shear stress are the key factors for enhanced glucan production with Schizophyllum commune. During batch cultivation control of or (specific oxygen uptake rate) was achieved by variation of the impeller speed. Biomass was modelled by using the carbon and oxygen balance derived from exhaust data. At mycel growth a of 0.042 h^–1 presents just the border before oxygen limitation arises and is simultaneously the optimum operation condition for maximum glucan formation. Related to an overall cultivation time of 72 h a maximum of both productivity (4.3 kg m^–3 d^–1) and yield (13 kg m^–3) were obtained.List of Symbols C kg m^–3 concentration - k _L a h ^–1 volume related oxygen transfer coefficient - K _s mol m^–3 substrate saturation constant - N rpm impeller speed - % oxygen partial pressure of the liquid phase - kg m^–3h^–1 oxygen uptake rate - h^–1 specific oxygen uptake rate, kg O₂ (kg biomass h)^–1 - t h time - yield coefficient (biomass formed/oxygen consumed) Greek Symbols h^–1 specific growth rate Indices O ₂ oxygen - X biomass - L liquid phase - * gas/liquid interface - S substrate (glucose) Dedicated to the 65th birthday of Professor Fritz Wagner.This work was kindly supported in parts by B. Braun Biotech International. The authors are grateful to Prof. Dr. Fritz Wagner for scientific support and appreciate the technical assistance of Detlev Rasch     

A sensitive and specific assay for glutathione with potential application to glutathione disulphide,using high-performance liquid chromatography–tandem mass spectrometry

We have utilised the combination of sensitivity and specificity afforded by coupling high-performance liquid chromatography (HPLC) to a tandem mass spectrometer (MS–MS) to produce an assay which is suitable for assaying glutathione (GSH) concentrations in liver tissue. The sensitivity suggests it may also be suitable for extrahepatic tissues. The method has been validated for GSH using mouse liver samples and also allows the assay of GSSG. The stability of GSH under conditions relevant to the assay has been determined. A 20-μl amount of a diluted methanol extract of tissue is injected with detection limits of 0.2 pmol for GSH and 2 pmol for GSSG. The HPLC uses an Altima C₁₈ (150×4.6 mm, 5 μm) column at 35°C. Chromatography utilises a linear gradient from 0 to 10% methanol in 0.1% formic acid over 5 min, with a final isocratic stage holding at 10% methanol for 5 min. Total flow rate is 0.8 ml/min. The transition from the M+H ion (308.1 m/z for GSH, and 613.3 m/z for GSSG) to the 162.0 m/z (GSH) and 355.3 m/z (GSSG) fragments are monitored.     

Diagnostic value of a dot immunobinding assay for human pulmonary hydatidosis

The diagnosis of human hydatidosis is primarily made using radiological and serological methods. Radiological methods are generally of low specificity and serological methods lack sensitivity, especially for pulmonary disease. In this study the capabilities of a new rapid test, the hydatid antigen dot immunobinding assay (HADIA), which was developed for the diagnosis of pulmonary hydatidosis, were studied and compared with another immunodiagnostic method, indirect hemagglutination (IHA). The study subjects included 18 patients, 9 women, 9 men; range 7 to 63 years; mean 30 years, with surgically proven pulmonary hydatidosis, a control group comprised of 14 patients; viral respiratory infections (1), cirrhosis (2), connective tissue disease (2), taeniasis (3), and 6 healthy donors. We found that the HA-DIA test had a sensitivity of 67% and specificity of 100%, and that the IHA test had a sensitivity of 50% and specificity of 100%. We conclude that HA-DIA is a simple, rapid, low cost assay that does not require instrumentation and has a higher sensitivity than IHA for the diagnosis of pulmonary hydatidosis.     

Development of a novel method for triterpenoidal saponins in rat plasma by solid-phase extraction and high-performance liquid chromatography tandem mass spectrometry

A novel method using high-performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) has been developed for the quantification of four triterpenoidal saponins (anemoside B4, pulsatilloside B, anemoside A3, and 23-hydroxybetulinic acid) in rat plasma following solid-phase extraction (SPE). The optimized procedure utilized off-line extraction of the analytes from plasma using polymeric (Strata-X) SPE cartridges. Detection and quantitation were performed by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) in a novel multiswitching monitoring mode. The analytes and internal standard (scutellarin) were analyzed using a Sapphire C18 column (250 × 4.6 mm, 5 μm) with a linear gradient elution. The mass transition ion pairs of the triterpenoidal saponins were executed as follows: m/z 1219.7/749.4 for anemoside B4, m/z 819.4/347.2 for pulsatilloside B, m/z 749.6/471.2 for anemoside A3, m/z 471.4/471.4 for 23-hydroxybetulinic acid, and m/z 461.1/285.0 for the internal standard. The specificity, linearity, accuracy, precision, recovery, matrix effect, and stabilities were validated for all analytes in the plasma samples. In conclusion, the validation results demonstrate that this method is robust and specific. This validated method is a novel technique for sample preparation and quantitation and was successfully applied to estimate the pharmacokinetics of triterpenoidal saponins.     

A new technique for continuous measurement of the heat of fermentation

Summary A special temperature control system has been developed and applied to continuous measuring of the heat evolved during a fermentation process. In this system, the fermentation broth was overcooled by a given constant cooling water flow. The excess heat removed from the fermentor was then made up by an immersion electrical heater. The action of the temperature controller was precisely monitored as it varied in response to the amount of heat produced by the microbial activities.The technique was used for determining the heat evolution byEscherichia coli grown on glucose. The ratio between quantities of total heat release and total oxygen consumption has been determined to be 0.556 MJ/mol O₂.The newly developed technique can be employed as an online sensor to monitor the microbial activities of either aerobic or anaerobic fermentation systems.Symbols C_c Heat capacity of cooling water (MJ/kg · °C) - C_p Heat capacity (MJ/kg · °C) - I Current of immersion heater (A) - K Constant in Equation (2) (h) - K Constant in Equation (13) (m³ · h · °C/MJ) - Q_c Flow rate of cooling water (m³/h) - Heat of agitation (MJ/m³ · h) - Heat dissipated by the bubbling gas (MJ/m³ · h) - Heat removal by the action of controller (MJ/m³ · h) - Heat of fermentation (MJ/m³ · h) - Heat loss to the surroundings (MJ/m³ · h) - Q_pass Constant average power dissipated by the immersion heater (MJ/m³ · h) - Fluctuating power dissipated by the immersion heater (MJ/m³ · h) - Power dissipated by the immersion heater (MJ/m³ · h) - T Temperature of fermentation broth (°C) - Constant average temperature of fermentation broth (°C) - Fluctuating temperature of fermentation broth (°C) - T_a Temperature of the ambient air (°C) - T_c Inlet temperature of cooling water (°C) - U₁A₁ Specific heat transfer coefficient for determination of heat loss to the surroundings (MJ/m³ · h · °C) - U₂A₂ Specific heat transfer coefficient for cooling surfaces (MJ/m³ · h · °C) - U₃A₃ Constant in Equation (16) (MJ/m³ · h · °C) - V Voltage of immersion heater (V) - V_L Liquid volume (m³) - OUR Oxygen uptake rate (mol O₂/m³ · h) Greek Letters H_fo The ratio between the total heat release and the total oxygen uptake (MJ/mol O₂) - _c Density of cooling water (kg/m³) - Time constant defined in Equation (6) (h) - _iM_iC_pi Heat capacity of system components (fermentation broth + fermentor jar + stainless steel) (MJ/m³ · °C)     

New potential biomarkers in the diagnosis of esophageal squamous cell carcinoma

Objective: To analyse the alterations of serum proteins in cases of esophageal squamous cell carcinoma (ESCC) in order to screen and validate serum marker patterns for the diagnosis of ESCC in the high-risk populations of Xinjiang, China. Methods: The serum proteomic patterns of 188 cases, including 139 patients with ESCC (54 Uygur, 45 Kazakh and 40 Han subjects) and 49 sex- and age-matched healthy controls, were detected using the SELDI-TOF-MS (surface-enhanced laser desorption/ionization–time of flight–mass spectrometry) technology with the CM10 ProteinChip. Differences in protein peaks between patients with ESCC and controls were analysed using the Biomarker Pattern Software, and a primary diagnosis model of ESCC was developed and validated with SVM (support vector machines). This model was further evaluated by a large-scale blind test. Results: Two hundred and eighty-three protein peaks were detected within the molecular range of 0–20?kDa, among which, 140 peaks were significantly different between ESCC cases and controls (p?m/z 5667, 5709, 5876, 5979, 6043 and 6102) was established with a sensitivity of 97.12% and a specificity of 83.87%. The large-scale blind test generated a sensitivity of 91.43% and a specificity of 88.89%. Conclusions: The differential protein peaks analysed by SELDI-TOF-MS may contain promising serum biomarkers for screening ESCC. The diagnostic model which combined only six protein peaks had a satisfactory discriminatory power. The model should be further evaluated in other populations of ESCC patients and tested against controls. The nature and function of the discriminating proteins have yet to be elucidated.     

Gas chromatographic-mass spectrometric identification and quantitation of urinary phenols after derivatization with 4-carbethoxyhexafluorobutyryl chloride, a novel derivative

Urinary phenol is analyzed widely to determine benzene exposure in humans. Most methods utilize direct measurements of phenols after extraction from urine using gas chromatography or high-performance liquid chromatography. We describe a novel derivatization of urinary phenols using 4-carbethoxyhexafluorobutyryl chloride after extraction from urine and subsequent analysis by gas chromatography-mass spectrometry. The derivative elutes at significantly higher temperature than phenol and the method is free from interferences from more volatile components in urine. We also observed excellent chromatographic properties of these derivatives. In addition, we observed strong molecular ions for the 4-carbethoxyhexafluoro butyryl derivative of phenol (m/z 344), p-cresol (m/z 358) and the internal standard 3,4-dimethylphenol (m/z 372) and other characteristic ions in the electron ionization, thus aiding in unambiguous identification of these compounds. The protonated molecular ions (m/z 373 for derivatized phenol, m/z 359 for derivatized p-cresol and m/z 373 for the internal standard) were the base peaks (relative abundance 100%) in the chemical ionization, although other secondary peaks were less abundant. The assay is linear for phenol concentration of 1–100 mg/l. The within-run and between-run precisions were 4.8% ( ) and 8.1% ( ) respectively, and the detection limit was 0.5 mg/l.     

Inconsistencies in standard approximations for selection coefficients at loci affecting a polygenic character

Inconsistencies exist in the standard expansions used to approximate selection coefficients for alleles at a locus underlying a quantitative character. Allelic (marginal) fitnesses obtained from expansions based on average excesses differ from allelic fitnesses obtained from expansions based on genotypic values. Similarly, the mean population fitness based on summing over either allelic or genotypic fitnesses usually differs mean population fitness obtained by averaging over the unrestricted phenotypic distribution. A consistent value of requires no variation in genotypic values. If, as suggested by Nagylaki (1984), expansions are corrected for the decrease in phenotypic variance resulting from conditioning on the presence of a particular allele or genotype, inconsistencies still exist. Unless W(z)[V _z p(z) + zp(z) + p(z)] dz = 0, where p(z) is the phenotypic probability density function, V _z the phenotypic variance, W( _z ) the fitness of phenotypic value z, the primes denote differentiation with respect to z, allelic fitnesses based on average effects differ from allelic fitnesses based on genotypic values. This condition must also be satisfied in order for either expansion to give a consistent , as first shown by Nagylaki. For arbitrary W(z), this is satisfied if and only if phenotypes are normally distributed.     

Liquid-phase axial mixing in a bubble column bioreactor containing yeast suspensions

Summary Liquid-phase axial mixing coefficients were evaluated in a 0.15 m x 2.0 m batch bubble column containing water and yeast-in-water suspensions of different concentrations. Air superficial velocities ranged from 0 to 0.06 m/s. Axial mixing coefficients were calculated from the residence time distribution to an NaCl tracer pulse using the Ohki and Inuoe model. No specific variations in the calculated coefficients were observed to result from the presence of yeast cells. There was fair agreement between the data thus obtained and the only available data on mixing in non-Newtonian CMC solution.Nomenclature C _E equilibrium tracer concentration g/l - C tracer concentration at time t g/l - d_h sparger hole diameter m - D _t tube diameter m - D _z axial mixing coefficient m²/s - g acceleration of gravity m/s² - H _B bubbling layer heigh m - L longitudinal dustance between tracer injection and detection points m - n 1,2,6 Eq. (3) - t time s - U_g gas superficial velocity m/s - U_t liquid superficial velocity m/s - V _r bubble relative velocity = m/s - V _t Linear relative velocity m/s - z axial distance m Greek _c wet cell volume farction - _g gas holdup - _l liquid holdup - _l viscosity of the liquid phase Pa/s - _l density of liquid or continuous phase g/ml     

Characterization of endogenous and recombinant forms of laccase-2, a multicopper oxidase from the tobacco hornworm, Manduca sexta

Laccases belong to the group of multicopper oxidases that exhibit wide substrate specificity for polyphenols and aromatic amines. They are found in plants, fungi, bacteria, and insects. In insects the only known role for laccase is in cuticle sclerotization. However, extracting laccase from the insect's cuticle requires proteolysis, resulting in an enzyme that is missing its amino-terminus. To circumvent this problem, we expressed and purified full-length and amino-terminally truncated recombinant forms of laccase-2 from the tobacco hornworm, Manduca sexta. We also purified the endogenous enzyme from the pharate pupal cuticle and used peptide mass fingerprinting analysis to confirm that it is laccase-2. All three enzymes had pH optima between 5 and 5.5 when using N-acetyldopamine (NADA) or N-β-alanyldopamine-alanyldopamine (NBAD) as substrates. The laccases exhibited typical Michaelis–Menten kinetics when NADA was used as a substrate, with K_m values of 0.46 mM, 0.43 mM, and 0.63 mM, respectively, for the full-length recombinant, truncated recombinant, and cuticular laccases; the apparent k_cat values were 100 min⁻¹, 80 min⁻¹, and 290 min⁻¹. The similarity in activity of the two recombinant laccases suggests that laccase-2 is expressed in an active form rather than as a zymogen, as had been previously proposed. This conclusion is consistent with the detection of activity in untanned pupal wing cuticle using the laccase substrate 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Immunoblot analysis of proteins extracted from both tanned and untanned cuticle detected only a single protein of 84 kDa, consistent with the full-length enzyme. With NBAD as substrate, the full-length recombinant and cuticular laccases showed kinetics indicative of substrate inhibition, with K_m values of 1.9 mM and 0.47 mM, respectively, and apparent k_cat values of 200 min⁻¹ and 180 min⁻¹. These results enhance our understanding of cuticle sclerotization, and may aid in the design of insecticides targeting insect laccases.     

Abundance,population dynamics and production of Chironomidae (Diptera) in an ul traoligotrophic lake in South Greenland

Macrozoobenthos of the ultraoligotrophic Lake 95 (61°N, 46°W, 8 ha, z_max=18 m, ) is composed of about 14 taxa dominated by 12 Chironomidae species. Abundance, life cycle, biomass and production were estimated for the six dominant taxa. Abundance declined fromca. 4150 at 2.5 m depth toca. 1400 ind m^–2 at 16 m depth and averagedca. 3200 ind m^–2 on a lakewide basis. By numbers,Heterotrissocladius changi andH. oliveri dominated the average fauna.H. changi was common at the 2.5 m and 5 m depth stations, whereasH. oliveri dominated from 5 m depth downwards. Chironomids showed mainly a 1-yr life cycle, but apparently bothHeterotrissocladius species had two contemporary cohorts with emergence in midsummer and late autumn/early spring, respectively. Average annual ratio was 4.2 and 4.6 forH. oliveri andH. changi, respectively. Annual production varied from 0.3 g ash-free dry weight (AFDW) m^–2 y^–1 at 16 m depth to 1.6 g AFDW m^–2 y^–1 at 2.5 m depthH. changi contributed 45%, fiveMicropsectra spp. 17% andH. oliveri 15% to total average production, which on a lakewide basis wasca. 1.1 g AFDW or 25 kJ m^–2 y^–1. Lake 95 thus belongs at the very low end of measured lake zoobenthic productions, which range from 10 kJ m^–2 y^–1 in Arctic lakes toca. 1600 kJ m^–2 y^–1 in highly eutrophic shallow lakes.     

Performance of a rapid immuno-chromatographic test (Schistosoma ICT IgG-IgM) for detecting Schistosoma-specific antibodies in sera of endemic and non-endemic populations

BackgroundSchistosomiasis, an acute and chronic parasitic disease caused by human pathogenic Schistosoma species, is a neglected tropical disease affecting more than 220 million people worldwide.For diagnosis of schistosomiasis, stool and urine microscopy for egg detection is still the recommended method, however sensitivity of these methods is limited. Therefore, other methods like molecular detection of DNA in stool, detection of circulating cathodic antigen in urine or circulating anodic antigen in urine and serum, as well as serological tests have gained more attention. This study examines the sensitivity and specificity of a rapid diagnostic test based on immunochromatography (Schistosoma ICT IgG-IgM, LD Bio, Lyon, France) for simultaneous detection of specific IgG and IgM antibodies in serum, against Schistosoma spp. in endemic and non-endemic populations.Methodology/Principal findingsFrozen banked serum samples from patients with confirmed schistosomiasis, patients with other helminth infections, patients with seropositive rheumatoid arthritis and healthy blood donors were used to assess the sensitivity and the specificity of the Schistosoma ICT IgG-IgM rapid diagnostic test.The test showed a sensitivity of 100% in patients with parasitologically confirmed schistosomiasis, irrespective of the species (S. mansoni, S. haematobium, S. japonicum, S. mekongi). In healthy blood donors and patients with rheumatoid factor positive rheumatoid arthritis from Europe, specificity was 100%. However, in serum samples of patients with other tissue invasive helminth infections, the test showed some cross-reactivity, resulting in a specificity of 85%.Conclusion/SignificanceWith its high sensitivity, the Schistosoma ICT IgG-IgM rapid diagnostic test is a suitable screening test for detection of Schistosoma specific antibodies, including S. mekongi. However, in populations with a high prevalence of co-infection with other tissue invasive helminths, positive results should be confirmed with other diagnostic assays due to the test’s imperfect specificity.     

LC/MS evaluation of metabolism and membrane transport of bombesin peptides

Two bombsin peptides, GRPR agonist [Aca-QWAVGHLM-NH₂] and antagonist [fQWAVGHL-NHEthyl] were evaluated. We employed the highly sensitive Waters Q-Tof Premier MS coupled with a UPLC system to identify the metabolites produced by rat hepatocytes or PC-3 human prostate cancer cells; and we utilized the AB/MDS 4000 Q-Trap LC/MS/MS system with highly sensitive quantitative and qualitative performance, to quantitatively analyze the internalization of GRPR agonist and antagonist in PC-3 cells. The major metabolites of both GRPR agonist and antagonist were the result of peptide bond hydrolysis between W and A which was demonstrated by observation of the N-terminal fragment m/z 446 (Aca-QW-OH) for agonist and m/z 480 (fQW-OH) for antagonist. Both peptides were also hydrolyzed between A and V which formed peaks m/z 517 [Aca-QWA-OH] and m/z 555 (VGHLM-NH2) for the agonist and m/z 551 [fQWA-OH] and m/z 452 (VGHL-NHEthyl) for the antagonist. The peptide agonist also formed a unique metabolite that resulted from hydrolysis of the C-terminal amide. The antagonist showed significantly slower metabolism as compared to the agonist in both rat hepatocytes and PC-3 cells. The antagonist also showed significantly lower PC-3 cell internalization rate than that of the agonist. In conclusion, the metabolism profiles of both GRPR agonist and antagonist peptides were identified by LC/MS. The antagonist peptide was more stable than the agonist peptide in rat hepatocyte incubation. One major factor could be the hydrolysis-resistant C-terminal L-NHEthyl group compared with the unsubstituted amide of the agonist. Another factor could be different amino acid sequences of the agonist and antagonist that may also influence the enzymatic hydrolysis. The antagonist ligand is potentially more useful for receptor-targeted imaging due primarily to its higher metabolic stability.     

Metabonomic models of human pancreatic cancer using 1D proton NMR spectra of lipids in plasma

In this study, we hypothesized that the altered insulin and glucose levels in male pancreatic cancer patients reported in a recent JAMA article would result in an altered lipid profile in the blood of pancreatic cancer patients when compared to controls (Stolzenberg-Solomon et al., 2005). Proton nuclear magnetic resonance (NMR) spectra of human lipophilic plasma extracts were used in order to build partial least squares discriminant function (PLS-DF) models that classified samples as belonging to the pancreatic control group or to the pancreatic cancer group. The sensitivity, specificity, and overall accuracy of the PLS-DF models based on 4 bins were 96%, 88%, and 92%, respectively. The sensitivity, specificity, and overall accuracy of the PLS-DF models based on 5 bins were 98%, 94%, and 96%, respectively. The sensitivity, specificity and overall accuracy of both the 4-bin and 5-bin PLS-DF models dropped only 1–2% during leave-25%-out cross-validation testing. Mass spectrometric profiling of phospholipids in plasma found three phosphatidylinositols that were significantly lower in pancreatic cancer patients than in healthy controls. The cancer models are based upon changes in lipid profiles that may provide a more sensitive and accurate diagnosis of pancreatic cancer than current methods that are based upon a single biomarker.     

High-performance liquid chromatographic-electrospray mass spectrometric determination of morphine and its 3- and 6-glucuronides: application to pharmacokinetic studies

A rapid and selective assay of morphine and its 3- and 6-glucuronides in serum, based on high-performance liquid chromatography-electrospray mass spectrometry has been developed. The analytes and the internal standard, codeine or naltrexone, were subjected to solid-phase extraction, using ethyl solid-phase extraction columns, prior to chromatography. A reversed-phase column and a gradient mobile phase consisting of water and methanol were used. The mass spectrometer was operated in the selected-ion monitoring mode. The following ions were used: m/z 286 for morphine, m/z 300 for codeine, m/z 342 for naltrexone, and m/z 462 for morphine 3- and 6-glucuronides. The limit of quantitation observed with this method was 10 ng/ml morphine, 50 ng/ml morphine-6-glucuronide and 100 ng/ml morphine-3-glucuronide. The present method proved useful for the determination of serum levels of the parent drug and its metabolites in pain patients, heroin addicts and in morphine-treated mice.     

The Distribution of Bacterio- and Mesozooplankton in the Coastal Waters of the White and Barents Seas

The total population density and the biomass of bacterioplankton, mesozooplankton, and phosphate-accumulating bacteria (PAB) were estimated during the 2000–2001 summer–autumn seasons in the coastal waters of the White and Barents Seas, which are subject to the action of tidal and sea currents, the inflow of riverine waters, and anthropogenic impact. In the shallow estuarine waters with salinities of 6.5–32 near the Chernaya, Pesha, and Pechora River mouths, the population of PAB fluctuated from 0.1 to 9.1 million cells/ml (0–36% of the total bacterial population). In pelagic seawaters, which are low in phosphates (12–50 g/l) and are characterized by an increased iron/phosphorus ratio (2.0–3.6), bacterioplankton amounted to 0.1–1.6 million cells/ml and was mainly represented by small organisms with a volume of 0.08–0.15 m³, commonly lacking intracellular polyphosphates. In the pelagic zone of the Barents Sea, the biomass of mesozooplankton (B _z) was comparable with that of bacterioplankton (B _b = 39–175 mg/m³), the B _b/B _z ratio being 1.4–4.6. Off the Varandeiskii, Pechora, and Kolguyev oil terminals, B _b increased to 155–300 mg/m³ and the B _b/B _z ratio rose to 1.4 to 50.3 (with an average value of 20.9), presumably due to the severe anthropogenic impact on these waters. In this case, the dense population of bacterioplankton (0.9–7.6 million cells/ml) was mainly represented by large cells (0.12–0.76 m³ in volume), most of which (3–43% of the total bacterioplankton population) contained polyphosphates. The chemical composition of these waters was characterized by an elevated content of the total phosphorus (65–128 g/l) and by a low iron/phosphorus ratio (0.9–1.2).