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PubMed1982

[Catecholamines, GH, cortisol, glucagon, insulin, and sex hormones in exercise and beta 1-blockade (author's transl)].

The effects of beta-1-adrenergic blockade (100 mg metoprolol) on metabolism in exercise was examined in 14 healthy males who worked for 50 min on a treadmill at 65% of their maximal exercise capacity. The tests were carried out in a double blind fashion. Glucose and lactate were determined in arterialized capillary blood, free fatty acids, glycerol, growth hormone, cortisol, glucagon, insulin, testosterone, and estradiol in serum, and adrenaline and noradrenaline in plasma. Lactate and glucose were not significantly affected by beta-1-adrenergic blockade, free fatty acids and glycerol were reduced by 50% and 30% respectively as compared with the unmedicated condition. Adrenaline and noradrenaline levels were increased by 104% and 54% respectively, growth hormone by 60%, cortisol by 72%, and glucagon by 36% when compared with the control experiments. Insulin and estradiol were unaffected, testosterone was depressed by 21% under medication. The results demonstrate that during prolonged exercise beta-1-adrenergic blockade depresses lipolysis. Energetic deficiency is prevented by counter-regulatory increases of various hormones. Consequently, from the metabolic point of view there is no indication of impairment of prolonged exercise capacity under beta-1-adrenergic blockade.

Adrenergic beta-Antagonists↗
PubMed1982

Immunobiological properties of a carboxy-terminal 53-amino acid peptide of the beta subunit of human chorionic gonadotropin.

Lengthening of the carboxy terminus unique region of beta-hCG from 30 to 45 amino acids was found in previous studies to improve immunogenicity and hormone neutralization capacity. The present study was carried out to determine whether further elongation of the peptide to 53 amino acids enhances to hormone neutralization capacity without loss of specificity characteristics. The peptide 93--145 of beta-hCG with substitution of cysteines at 93, 100 and 110 by alpha-aminobutyric acid was synthesized by solid phase and conjugated to tetanus toxoid by an active ester method. Rabbit antibodies against this conjugate reacted with CTP-53 and CTP-45 with a parallel slope in anti-CTP-53-[125I]Tyr-CTP--53 radioimmunoassay system. Other CTPs, e.g. CTP-26, CTP-31 and CTP-35 competed with lower efficiency; 50% inhibition of binding was obtained with 10-100 pmol/tube with these peptides instead of 0.5 pmol/tube for the homologous CTP-53. Anti-CTP-53 reacted with both beta-hCG and hCG but around twenty times greater amount of hCG was required to give 50% inhibition of binding as compared to CTP-53. The antigen binding capacity of anti-CTP-53 was around 4000 ng/ml for CTP-53 and 25 ng/ml for hCG. The anti-CTP-53 sera retained non-cross-reactivity with hLH as determined by direct binding with [125I]hLH and by competitive inhibition of CTP-53 binding with anti-CTP-53. Anti-CTP-53 neutralized the bioactivity of hCG in the Leydig cell bioassay and in the mouse uterine weight gain assay. Anti-CTP-53 antibodies were about three times more effective than anti-CTP-45 in their capacity to neutralize the bioactivity of hCG, though still substantially poorer than anti-beta-hCG sera in this respect.

Amino Acids↗
PubMed1998

Interstitial lung disease in systemic sclerosis: comparison of BALF lymphocyte phenotype and DLCO impairment.

Patients with scleroderma (systemic sclerosis-SSc) frequently develop an interstitial lung disease. The role of lymphocytes in fibrosing alveolitis preceding lung fibrosis has been established. The purpose of this work was to evaluate cell profiles and lymphocyte phenotypes in the bronchoalveolar lavage (BAL) fluid and to correlate them with depression in lung function tests detected by depletion of diffusing capacity (DLCO). BAL was carried out in 25 untreated, non-smoking patients suffering from diffuse scleroderma and in 12 healthy non-smoking volunteers. For the analysis of lymphocyte sub-sets flow cytometry and monoclonal antibodies were used. The following cell sub-types were counted: T lymphocytes, B lymphocytes, helper lymphocytes, suppressor/cytotoxic lymphocytes, natural killer cells, cytotoxic T lymphocytes and activated T lymphocytes. The total cell count was higher in the group of patients with mild and moderate impairment in DLCO. The percentage of lymphocytes was greater in patients with DLCO lower than 65% of the predicted value since neutrophilia was found in patients with severe DLCO depletion, i.e. significant when compared with healthy subjects. The proportions of suppressor/cytotoxic lymphocytes and of activated T lymphocytes were higher in patients than in controls. The statistical analysis revealed significant differences between patients with moderate and mild changes in DLCO and the healthy volunteers. A decreased helper/suppressor ratio was noticed in these patients. We concluded that the BALF lymphocyte phenotype analysis may reflect the features of alveolitis in patients with SSc.

Adult↗
PubMed1985

Alterations of the eicosanoid synthetic capacity of rat brain microvessels following ischemia: relevance to ischemic brain edema.

To know the mechanism underlying ischemic brain edema, a time-course analysis of the eicosanoid synthetic capacity of brain microvessels was carried out using unilateral, middle cerebral artery (MCA)-occluded rats. Concomitant with the development of brain edema the synthetic capacity of all products, including cyclooxygenase and lipoxygenase products, increased significantly. Next the effects of 15-hydroperoxyarachidonic acid (15-HPAA) on the synthetic capacity of microvessels were examined. The drug caused a generalized increase of each product, the profile of which was similar to that obtained with ischemic hemispheres, although the ratios of each product differed somewhat among them. The enhanced synthesis of eicosanoids by 15-HPAA was markedly suppressed by radical scavengers such as alpha-tocopherol, hydroquinone, and 1,2-bis(nicotineamide)-propane. Furthermore, the evolution of brain edema was virtually suppressed by the systemic administration of 1,2-bis(nicotineamide)-propane. The above result suggests that the enzyme activity of the arachidonic acid (AA) cascade of microvessels is stimulated by its own products. Such a mechanism will form a vicious cycle that accelerates the accumulation of free radicals within microvessels and thus may play a role in the progressing disruption of the blood-brain barrier (BBB) following ischemia.

Animals↗
PubMed1994

Mechanism of enhanced susceptibility to sepsis following hemorrhage. Interleukin-10 suppression of T-cell response is mediated by eicosanoid-induced interleukin-4 release.

OBJECTIVES: To determine (1) whether interleukin-10 (IL-10) contributes to depressed T-cell responses observed following hemorrhage and (2) what effect other immunosuppressive agents known to play a role in hemorrhage have on IL-10 release. DESIGN: Hemorrhage was induced in C3H/HeN mice. The mice were resuscitated and then killed 2 hours after hemorrhage to obtain plasma, splenocytes, splenic macrophages, and splenic T cells. RESULTS AND CONCLUSIONS: Decreased splenocyte/T-cell proliferation was associated with enhanced release of IL-10 by cells from hemorrhaged mice. However, unlike T cells, IL-10 release by macrophages was not comparatively elevated. While no changes were seen in systemic plasma levels of IL-10, the role of IL-10 as a localized immunosuppressant was demonstrated by the ability of IL-10 monoclonal antibody to restore T-cell proliferation following hemorrhage. Furthermore, elevated IL-10 release was prevented by the addition of ibuprofen or monoclonal antibody against transforming growth factor beta or IL-6. Since these agents have direct or indirect influences on prostanoid synthesis, studies were carried out examining the capacity of varying concentrations of prostaglandin E2 (PGE2) to augment IL-10 release by murine cloned Th2 cells (D10.G4.1) and by T cells from sham-operated or hemorrhaged mice. While the addition of PGE2, 10(-9) mol/L, potentiated the release of IL-10, this effect appears to be indirect, since the incorporation of monoclonal antibody to IL-4 prevented the release of IL-10 by PGE2-treated cells from sham-operated or hemorrhaged mice. Such a mechanism of eicosanoid-induced IL-4/IL-10 cell-mediated immunosuppression may directly contribute to the decreased capacity to ward off infectious challenge seen following hemorrhage.

Animals↗
PubMed1986

Monoclonal antibodies labeled with polymeric paramagnetic ion chelates.

Polymeric paramagnetic ion chelate molecules were synthesized and covalently linked to monoclonal antibodies. The labeled antibodies retained their antigen binding capacity in vitro while carrying up to an average of 50 paramagnetic ion chelates, enabling specifically bound antibody concentrations less than 2.0 microM to significantly reduce proton longitudinal relaxation times.

Animals↗
PubMed1985

pH-induced changes in mitotic and developmental patterns in sea urchin embryogenesis. II. Exposure of sperm.

pH decrease and increase were tested for their ability to affect the fertilizing capacity of sea urchin sperm, as well as to induce developmental defects and mitotic abnormalities in the embryos generated by pretreated sperm. Seawater (sw) at different pH values was obtained by mixing acidified (HCl) sw and alkalinized (KOH) sw. Thereafter sperm were exposed to different pHs for a defined time interval, or subjected to inactivation, while suspended in sw at defined pHs, as long as their fertilizing capacity was maintained. The study was carried out over the pH range 5-9; sperm showed optimal fertilizing capacity between pH 6 and 7. Below pH 6 and above pH 8 a drop in the fertilizing capacity was observed, whereas at normal sw pH (8.0-8.2) sperm showed intermediate values. pH decrease in sperm suspension induced a reproducible increase in developmental defects and mitotic abnormalities in the offspring of pretreated sperm. This effect displayed a dose-response relationship, which was most evident for pH ranging from 7 to 8. The effects of decreased pH were detected as well in terms of quantitative changes in mitotic activity, which decreased in embryos generated by sperm exposed to low pH (5-6). The results are consistent with the induction of genetic damage following exposure of sperm to low pHs. This observation suggests a genotoxic action of hydronium ions per se. Another possible explanation for the observed genotoxicity of decreased pH might be based on the pH-dependent activity of several genotoxins present in sw at trace levels.

Animals↗
PubMed2000

Sequence analysis of mitochondrial 16S ribosomal RNA gene fragment from seven mosquito species.

Mosquitoes are vectors for the transmission of many human pathogens that include viruses, nematodes and protozoa. For the understanding of their vectorial capacity, identification of disease carrying and refractory strains is essential. Recently, molecular taxonomic techniques have been utilized for this purpose. Sequence analysis of the mitochondrial 16S rRNA gene has been used for molecular taxonomy in many insects. In this paper, we have analysed a 450 bp hypervariable region of the mitochondrial 16S rRNA gene in three major genera of mosquitoes, Aedes, Anopheles and Culex. The sequence was found to be unusually A+T rich and in substitutions the rate of transversions was higher than the transition rate. A phylogenetic tree was constructed with these sequences. An interesting feature of the sequences was a stretch of Ts that distinguished between Ae-des and Culex on the one hand, and Anopheles on the other. This is the first report of mitochondrial rRNA sequences from these medically important genera of mosquitoes.

Animals↗
PubMed2001

Fractal dimension of K1735 mouse melanoma clones and spheroid invasion in vitro.

An in vitro tumour-host confrontation method to investigate the invasion behaviour of cancer has been applied to K1735 mouse melanomas. Fluorescently labelled spheroids of cancer cells and host cells were confronted and the temporal course of cancer invasion into the host was investigated using confocal laser scanning microscopy. To improve the quantitative data of this method, the boundary images of the fluorescently labelled confrontation pairs were treated as fractals. The physical and mathematical framework for determination of the fractal capacity dimension is widely used in biology and medicine and has proved to be a very useful tool for describing the cancer invasion process. The fractal capacity dimension determination was carried out by dilation of the binary boundaries of the objects, which were treated as an estimate of the Minkowski-Bouligand dimension. The fractal dimension correlated well with the degree of invasion of the K1735-M2 clone. Control experiments, with host-host confrontations and various K1735 clones with reduced invasiveness, support these results.

Animals↗
PubMed1986

Rod influence on cone flicker detection: variation with retinal eccentricity.

Previous studies have shown that cone flicker thresholds are influenced by the adaptation state of the rod system. We have examined how the properties of this rod-cone flicker interaction differ with retinal eccentricity. The threshold for detecting 25 Hz flicker was measured in the dark-adapted eye, against a rod-saturating Ganzfeld background and following a Ganzfeld bleach. The magnitude of the interaction, defined as the difference between light- and dark-adapted flicker thresholds, covaries with changes in rod absolute threshold across the visual field. At a given eccentricity, the magnitude of the interaction is constant for test diameters ranging from 7' to 1.7 degrees, indicating that variations in magnitude with eccentricity do not result from changes in spatial summation properties. The measurement of cone flicker thresholds during bleaching recovery provides evidence that variations in the magnitude of the rod-cone flicker interaction with retinal eccentricity may result from differences in the channel capacity of the pathway carrying the threshold-elevating signal from rods.

Adaptation, Ocular↗
PubMed1995

The thermodynamics of association and unfolding of the 205-316 C-terminal fragment of thermolysin.

The 205-316 C-terminal fragment of thermolysin has been studied by differential scanning calorimetry at pH values 2.5, 3.0, 3.5, 4.0 and 5.0 and at a constant ionic strength of 130 mM. The thermal unfolding of the fragment occurs at thermodynamic equilibrium under our experimental conditions. The effect of sample concentration at the different pH values on the calorimetric traces is consistent with a monomer-dimer equilibrium of the folded fragment, which undergoes thermal unfolding into individual fragments. Equilibrium sedimentation experiments at 10 degrees C and different pH values confirm the presence of the association equilibrium and provide the value of the dimerization constants. The global analysis of the calorimetric, heat capacity curves has been carried out by a multidimensional fitting to the model N2<-->2N<-->2U. The analysis leads to a complete thermodynamic characterization of both the association and unfolding processes of the fragment. The resulting thermodynamic functions suggest a partially unfolded structure for both the monomeric and dimeric fragment, as well as a conformational change linked to the association process. Our results are discussed in terms of the structural information currently available and compared with the energetics of unfolding of the shorter 255-316 dimeric C-terminal fragment of thermolysin (Conejero-Lara, F., De Filippis, V., Fontana, A. and Mateo, P.L. (1994) FEBS Lett. 344, 154-156). The presence of the additional 50 residues increases the relative population of the 205-316 monomeric fragment versus that of the 255-316 fragment.

Calorimetry, Differential Scanning↗
PubMed1992

Respiratory electron transfer activity in an asolectin-isooctane reverse micellar system.

Bovine heart submitochondrial particles (SMP) were solubilized in an asolectin isooctane reverse micellar system and the functionality of the respiratory chain was tested by spectroscopic and amperometric techniques. Electron transfer rate supported by NADH was very slow as evidenced by the low cytochrome reduction levels attained over long incubation periods. In the presence of KCN, NADH caused 34% and 12.5% reduction of the cytochromes aa3 and c, respectively, and negligible reduction of cytochrome b. Supplementation of the system with menadione rose the NADH-dependent reduction of all the cytochromes to levels that were close to the total content. However, no measurable O2 uptake activity took place in the presence of NADH plus menadione, or with ascorbate (or NADH) plus TMPD reducing systems. Therefore, it is suggested that in the organic medium, electron transfer from NADH to O2 is arrested at the terminal oxidase step. Cytochrome oxidase reduced by ascorbate (or NADH) plus TMPD seems to be trapped in its half reduced state (ie, a2+ a3(3+)). Although it is poorly reactive with O2, it can transfer electrons back to cytochrome c and TMPD. The electron transfer block to O2 was overcome when PMS was used instead of TMPD. This seems to be due to the recognized capacity of PMSH2 to carry out simultaneous reduction of both a CuA and a3 CuB redox centers of cytochrome oxidase. The cytochrome oxidase reaction in the organic solvent was highly sensitive to KCN (Ki 1.9 microM) and showed bell-shaped kinetics towards the PMS concentration and a sigmoidal response to water concentration, reaching its maximal turnover number (18 s-1) at 4 mM PMS and 1.1% (v/v) water.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Effects of waterborne iron overload and simulated winter conditions on acute physiological stress response of whitefish, Coregonus lavaretus.

Two-year-old whitefish (Coregonus lavaretus) were exposed for 30 days to episodic iron overload in iron-rich humic water (5%) supplemented with inorganic iron (5 mg FeL(-1)). Two parallel laboratory exposures were performed, one under conditions simulating winter and the other under conditions simulating spring. After exposure, some of the fish were subjected to acute handling stress in the form of a short air challenge to reveal possible modification of the primary and secondary stress responses. In whitefish sampled without additional handling, iron accumulated in the liver (under spring conditions) and gills (under winter and spring conditions); plasma catecholamine and beta-estradiol (both winter and spring groups) as well as blood hematocrit (winter group only) levels were depressed; blood glucose (winter group only) and red blood cell (RBC) Na+ levels (spring group only) were increased. In handled whitefish, liver glycogen phosphorylase (GPase), RBC, and blood glucose stress responses were impaired by the applied exposure conditions, which reflected natural iron-rich humic water. Exposure also removed some physiological effects of the applied ambient conditions: plasma catecholamines and beta-estradiol, gill Na+/K+ -ATPase, and RBC K+ concentration were not different in two iron-exposed fish groups, whereas there was a difference in reference fish. Thus, the physiological effects of this type of subchronic exposure, together with alterations in the acute stress response, can lead to incorrect conclusions being drawn from the results, if the effects of time-dependent stress response are ignored. In conclusion, waterborne iron overload may impair the optimal capacity of whitefish to carry out their normal physiological functions such as responding to external threats.

Adaptation, Physiological↗
PubMed2005

The investigation of parameters affecting boron removal by electrocoagulation method.

Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm2. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl2. Added CaCl2 increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions.

Boron↗
PubMed2006

Liquid phase adsorption of Crystal violet onto activated carbons derived from male flowers of coconut tree.

Adsorption of Crystal violet, a basic dye onto phosphoric and sulphuric acid activated carbons (PAAC and SAAC), prepared from male flowers coconut tree has been investigated. Equilibrium data were successfully applied to study the kinetics and mechanism of adsorption of dye onto both the carbons. The kinetics of adsorption was found to be pseudo second order with regard to intraparticle diffusion. The pseudo second order is further supported by the Elovich model, which in turn intensifies the fact of chemisorption of dye onto both the carbons. Quantitative removal of dye at higher initial pH of dye solution reveals the basic nature of the Crystal violet and acidic nature of the activated carbons. Influence of temperature on the removal of dye from aqueous solution shows the feasibility of adsorption and its endothermic nature. Mass transfer studies were also carried out. The adsorption capacities of both the carbons were found to be 60.42 and 85.84 mg/g for PAAC and SAAC, respectively. Langmuir's isotherm data were used to design single-stage batch adsorption model.

Adsorption↗
PubMed2006

Process development for the removal and recovery of hazardous dye erythrosine from wastewater by waste materials-Bottom Ash and De-Oiled Soya as adsorbents.

Erythrosine is a water-soluble xanthene class of dye. It is widely used as colorant in foods, textiles, drugs and cosmetics. It is highly toxic, causes various types of allergies, thyroid activities, carcinogenicity, DNA damage behaviour, neurotoxicity and xenoestrogen nature in the humans and animals. The photochemical and biochemical degradation of the erythrosine is not recommended due to formation of toxic by-products. The present paper is an attempt to remove erythrosine from wastewater using adsorption over Bottom Ash-a power plant waste and De-Oiled Soya-an agricultural waste. Under the batch studies, effect of concentration of dye, temperature, pH of the solution, dosage of adsorbents, sieve size of adsorbents, etc., have been studied for the uptake of the dye over both adsorbents. The adsorption process verifies Langmuir and Freundlich adsorption isotherms in both the cases and based on the data different thermodynamic parameters have been evaluated. Batch studies also include kinetic measurements, rate constant study, mass transfer behaviour and establishment of mechanistic pathway for both the cases. For the bulk removal of the dye column operations have been carried out and breakthrough capacities of the Bottom Ash and De-Oiled Soya columns have been calculated. Attempts have also been made for the recovery of the adsorbed dye from exhausted columns by eluting dilute NaOH and more than 90% of the dye was recovered.

Adsorption↗
PubMed2006

Oxidative stress, sperm survival and fertility control.

The human spermatozoon is highly susceptible to oxidative stress. This process induces peroxidative damage in the sperm plasma membrane and DNA fragmentation in both the nuclear and mitochondrial genomes. Such stress may arise from a variety of sources including a lack of antioxidant protection, the presence of redox cycling xenobiotics, infiltrating leukocytes and excess reactive oxygen species production by the spermatozoa. Whenever the levels of oxidative stress in the male germ line are high, the peroxidation of unsaturated fatty acids in the sperm plasma membrane ensures that normal fertilization cannot occur. However, at lower levels of oxidative stress, spermatozoa may retain their capacity for fertilization while carrying significant levels of oxidative damage in their DNA. Epidemiological evidence suggests that subsequent aberrant repair of such damage in the zygote may result in the creation of mutations associated with pre-term pregnancy loss and a variety of pathologies in the offspring, including childhood cancer. Thus, while the induction of oxidative stress in spermatozoa is causally involved in the aetiology of male infertility, the prospects of using such a strategy for male contraception is fraught with potential problems, should the suppression of fertility be incomplete and DNA-damaged spermatozoa gain access to the oocyte.

Contraception↗
PubMed1995

Thermodynamic determination of the Na+: glucose coupling ratio for the human SGLT1 cotransporter.

Phlorizin-sensitive currents mediated by a Na-glucose cotransporter were measured using intact or internally perfused Xenopus laevis oocytes expressing human SGLT1 cDNA. Using a two-microelectrode voltage clamp technique, measured reversal potentials (Vr) at high external alpha-methylglucose (alpha MG) concentrations were linearly related to In[alpha MG]o, and the observed slope of 26.1 +/- 0.8 mV/decade indicated a coupling ratio of 2.25 +/- 0.07 Na ions per alpha MG molecule. As [alpha MG]o decreased below 0.1 mM, Vr was no longer a linear function of In[alpha MG]o, in accordance with the suggested capacity of SGLT1 to carry Na in the absence of sugar (the "Na leak"). A generalized kinetic model for SGLT1 transport introduces a new parameter, Kc, which corresponds to the [alpha MG]o at which the Na leak is equal in magnitude to the coupled Na-alpha MG flux. Using this kinetic model, the curve of Vr as a function of In[alpha MG]o could be fitted over the entire range of [alpha MG]o if Kc is adjusted to 40 +/- 12 microM. Experiments using internally perfused oocytes revealed a number of previously unknown facets of SGLT1 transport. In the bilateral absence of alpha MG, the phlorizin-sensitive Na leak demonstrated a strong inward rectification. The affinity of alpha MG for its internal site was low; the Km was estimated to be between 25 and 50 mM, an order of magnitude higher than that found for the extracellular site. Furthermore, Vr determinations at varying alpha MG concentrations indicate a transport stoichiometry of 2 Na ions per alpha MG molecule: the slope of Vr versus In[alpha MG]o averaged 30.0 +/- 0.7 mV/decade (corresponding to a stoichiometry of 1.96 +/- 0.04 Na ions per alpha MG molecule) whenever [alpha MG]o was higher than 0.1 mM. These direct observations firmly establish that Na ions can utilize the SGLT1 protein to cross the membrane either alone or in a coupled manner with a stoichiometry of 2 Na ions per sugar, molecule.

Animals↗