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PubMed1989

[The transformation of gamma-tocopherol to alpha-tocopherol in the animal organism; a generational study in rats].

The biosynthesis of alpha-tocopherol, the most effective vitamer among the vitamin E-group, is found only in higher plants and microorganisms. Due to the lack of the shikimate pathway, animals are not able to synthesize alpha-tocopherol. Also not found is a whole enteral synthesis; only the conversion of dimethyletocol to trimethyletocol seems to be possible. Using four generations of rats, we sought to determine: Is a transformation of gamma-tocopherol to alpha-tocopherol in the animal body possible? Are there any differences in the transformation rates in organs, tissues, or in the entire body along the generations? Does gut flora play any role in the conversion of gamma-tocopherol? Is it possible to increase the efficiency of the transformation by supplying additional CH3-groups? Wistar rats were fed a semisynthetic basal diet, supplemented with 78.8 mg DL-gamma-tocopherol/kg in the first three generations (F1-F3). In the fourth generation (F4), some of the animals were fed a vitamin E-free diet and gamma-tocopherol (approx. 1.5 mg on alternate days) was injected s.c. Two other groups of animals received the basal diet containing additional methionine (0.25%) or choline (0.45%), as well as gamma-tocopherol (as in F1-F3). alpha- and gamma-tocopherol were analyzed by HPTLC in the whole body and in serum, liver, heart, lung, gut, gonads, and feces. The ratio of alpha-/gamma-tocopherol (micrograms/micrograms) as transformation rate and vitamin E-biopotency (microgram alpha-tocopherol equivalents/g) were calculated. Growth and fertility were normal until the fourth generation; no abnormal developments could be recognized. alpha-tocopherol was found in the whole-body as well as in all tissues and organs. In the whole-body, vitamin E-biopotency decreased 25-70% in F2 and F3. On the other hand, the increase of the transformation rate of gamma- to alpha-tocopherol amounted to 23% (F2) and 168% (F3). Highest conversion rates were found in F2 and F3 for feces, followed by gonads and lungs; the lowest rates were found for serum and liver. Due to the s.c. injection of gamma-tocopherol, feces showed a four-times lower transformation rate in F4 than in F3. There was an increase in heart, gut, lung and serum for both transformation rate and vitamin E-biopotency. These parameters could be improved also by the additional supplements of methionine and choline. Both methyl-group-donators revealed nearly the same positive effect. The results show that the animal organism can adapt to gamma-tocopherol supply over generations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Control of luteinizing hormone-releasing hormone pulse generation in nonhuman primates.

1. The pulsatile release of luteinizing hormone-releasing hormone (LHRH) is critical for reproductive function. However, the exact mechanism of LHRH pulse generation is unclear. The purpose of this article is to review the current knowledge on LHRH pulse generation and to discuss a series of studies in our laboratory. 2. Using push-pull perfusion in the stalk-median eminence of the rhesus monkey several important facts have been revealed. There is evidence indicating that LHRH neurons themselves have endogenous pulse-generating mechanisms but that the pulsatility of LHRH release is also modulated by input from neuropeptide Y (NPY) and norepinephrine (NE) neurons. The release of NPY and NE is pulsatile, with their pulses preceding or occurring simultaneously with LHRH pulses, and the neuroligands NPY and NE and their agonists stimulate LHRH pulses, while the antagonists of the ligands suppress LHRH pulses. 3. The pulsatile release of LHRH increases during the estrogen-induced LH surge as well as the progesterone-induced LH surge. These increases are partly due to the stimulatory effects of estrogen and progesterone on NPY neurons. 4. An increase in pulsatile LHRH release occurs at the onset of puberty. This pubertal increase in LHRH release appears to be due to the removal of tonic inhibition from gamma aminobutyric acid (GABA) neurons and a subsequent increase in the inputs of NPY and NE neurons to LHRH neurons. 5. There are indications that additional neuromodulators are involved in the control of the LHRH pulse generation and that glia may play a role in coordinating pulses of the release of LHRH and neuromodulators. 6. It is concluded that the mechanism generating LHRH pulses appears to comprise highly complex cellular elements in the hypothalamus. The study of neuronal and nonneuronal elements of LHRH pulse generation may serve as a model to study the oscillatory behavior of neurosecretion.

Animals↗
PubMed1995

Role of scalar protons in metabolic energy generation in lactic acid bacteria.

Lactic acid bacteria are able to generate a protonmotive force across the cytoplasmic membrane by various metabolic conversions without involvement of substrate level phosphorylation or proton pump activity. Weak acids like malate and citrate are taken up in an electrogenic process in which net negative charge is translocated into the cell thereby generating a membrane potential. The uptake is either an exchange process with a metabolic end-product (precursor/ product exchange) or a uniporter mechanism. Subsequent metabolism of the internalized substrate drives uptake and results in the generation of a pH gradient due to the consumption of scalar protons. The generation of the membrane potential and the pH gradient involve separate steps in the pathway. Here it is shown that they are nevertheless coupled. Analysis of the pH gradient that is formed during malolactic fermentation and citrate fermentation shows that a pH gradient, inside alkaline, is formed only when the uptake system forms a membrane potential, inside negative. These secondary metabolic energy generating systems form a pmf that consists of both a membrane potential and a pH gradient, just like primary proton pumps do. It is concluded that the generation of a pH gradient inside alkaline, upon the addition of a weak acid to cells is diagnostic for an electrogenic uptake mechanism translocating negative charge with the weak acid.

Cell Membrane↗
PubMed1991

Protective effect of carboxyethylgermanium sesquioxide (Ge-132) on superoxide generation by 60Co-irradiated leukocytes.

The carboxyethylgermanium sesquioxide, Ge-132, is an organogermanium compound which has been shown to modulate leukocyte functions. In this study, we examined the effect of Ge-132 on the generation of superoxide radicals (O2-) either from leukocytes or in cell-free system, employing the highly sensitive 2-methyl-6-[p-methoxy-phenyl]-3,7-dihydroimidazo[1,2-alpha]pyra zin-3-one (MCLA)-dependent chemiluminescence method and the specific electron spin resonance/spin trapping method, respectively. In addition, the in vitro protective effect of Ge-132 on the leukocytes irradiated with 60Co was studied. The incubation with Ge-132 resulted in an increase in basal O2- release of intact leukocytes, but had no effect on O2- generation from leukocytes stimulated with phorbol myristate acetate (PMA). Irradiation with 60Co decreased the O2- generation from leukocytes in a dose-dependent manner. Ge-132 had no effect on basal O2- release from 60Co-irradiated leukocytes, but it prevented the decrease in PMA-stimulated O2- generation by irradiated leukocytes. Ge-132 itself had no superoxide scavenging activity in cell-free system. On the other hand, higher concentrations of Ge-132 had decreasing effects on both basal O2- release and PMA-stimulated O2- generation from leukocytes, but they did not affect leukocyte viability. Above results indicate that 1) Ge-132 can stimulate the basal O2- release from leukocytes, 2) Ge-132 can prevent the decrease of O2- generation by 60Co-irradiated leukocytes, 3) in higher concentrations, Ge-132 may have a membrane stabilizing effect.

Antineoplastic Agents↗
PubMed1995

NO chi generation by cultured small intestinal epithelial cells.

The effect of cytokines, growth factors, mitogens, and bacterial products on nitric oxide (NO) generation by monolayers of small intestinal epithelial cells-6 (IEC-6) cells was evaluated. Subconfluent IEC-6 cells were maintained in DMEM containing 5% fetal calf serum and after 16-24 hr of incubation, the medium was replaced with fresh medium in the presence or absence of calcium ionophore (CaI), L-NAME, L-NNA, individual growth factors, cytokines, or mitogens. After 72 hr of culture, the media supernatant was collected and NO chi generation was determined. NO synthase activity was determined in sonicated supernatants of IEC-6 cells by [14C] arginine conversion to citrulline. NO chi generation in subconfluent cultures was greater than in fully confluent cultures, suggesting contact inhibition. NO chi generation by IEC-6 cells was significantly increased by CaI and inhibited by L-NAME and L-NNA. LPS, IL-1 beta, IL-2, IL-8, IFN-8, TFN-alpha, EGF, TGF-alpha, bFGF, and PHA significantly increased NO chi generation. NO synthase activity in IEC-6 cells (4.2 +/- 1.7 pmol/min/10(6) cells) was NADPH dependent. These results suggest that stimulation of NO chi generation by intestinal epithelial cells through cytokine bacterial products and mitogens may be one of the mechanisms responsible for their effects in the intestinal tract.

Animals↗
PubMed1997

Multichannel wavelet-type decomposition of evoked potentials: model-based recognition of generator activity.

Scalp recording of electrical events allows the evaluation of human cerebral function, but contributions of the specific brain structures generating the recorded activity are ambiguous. This problem is ill-posed and cannot be solved without physiological constraints based on the spatio-temporal characteristics of the generators' activity. In our model-based analysis of evoked potentials for the purpose of generator activity detection, multichannel scalp-recorded signals are decomposed into a combination of wavelets, each of which can describe the neural mass coherent activity of cell assemblies. Elimination of contributions of specific generators and/or distributed background activity can produce physiologically motivated time-frequency filtering. The decomposition and filtering procedures are demonstrated by three examples; simulation of the surface manifestation of known intracranial generators; decomposition and reconstruction of auditory brainstem evoked potentials which reflect the differences among generators of these potentials; and cognitive components of evoked potentials which are diminished in the averaged recording but are clearly detected in single-trial signals.

Algorithms↗
PubMed1998

Linear servo-controlled pressure generator for forced oscillation measurements.

In respiratory input impedance measurements, the low-frequency range contains important clinical and physiological information. However, the patient's spontaneous ventilation can contaminate the data in this range, leading to unreliable results. Unbiased estimators are a good alternative to overcome this problem, provided that the generator is considered linear. This condition is not fulfilled by most existing generators as they are based on loudspeakers, which have strong nonlinearities. The present work aims to contribute to the solution of this problem, and describes a pressure generator that minimises the nonlinearities by an optical sensor placed in a position feedback loop. The static evaluation shows a high linearity for the optical system. The well known frequency response of pressure transducers is used in the dynamic evaluation of the instrument. The analysis of the generator shows that the use of position feedback improved the frequency response. The total harmonic distortion (THD) measurement shows that closed loop resulted in an effective decrease in the nonlinearities. The reduction of THD achieved by the servo-controlled generator can contribute to the practical implementation of the unbiased estimators, increasing the reliability of the impedance data, especially in the low-frequency range. This system is compared with conventional generators and with another servo-controlled system.

Biomedical Engineering↗
PubMed2001

Characteristics of human dendritic cells generated in a microgravity analog culture system.

Generation of an effective immune response requires that antigens be processed and presented to T lymphocytes by antigen-presenting cells, the most efficient of which are dendritic cells (DC). Because of their influence on both the innate and the acquired arms of immunity, a defect in DC would be expected to result in a broad impairment of immune function, not unlike that observed in astronauts during or after space flight. In the study reported here, we investigated whether DC generation and function are altered in a culture environment that models microgravity, i.e., the rotary-cell culture system (RCCS). We observed that RCCS supported the generation of DC identified by morphology, phenotype (HLA-DR+ and lacking lineage-associated markers), and function (high allostimulatory activity). However, the yield of DC from RCCS was significantly lower than that from static cultures. RCCS-generated DC were less able to phagocytose Aspergillus fumigatus conidia and expressed a lower density of surface HLA-DR. The proportion of DC expressing CD80 was also significantly reduced in RCCS compared to static cultures. When exposed to fungal antigens, RCCS-generated DC produced lower levels of interleukin-12 and failed to upregulate some costimulatory/adhesion molecules involved in antigen presentation. These data suggest that DC generation, and some functions needed to mount an effective immune response to pathogens, may be disturbed in the microgravity environment of space.

Antigens, CD34↗
PubMed2005

Ten-year change in disability prevalence and related factors in two generations of French elderly community dwellers: data from the PAQUID study.

BACKGROUND AND AIMS: Some studies have reported a decline in disability prevalence in older people, but few data were available for Europe, especially for France. Our aim was to study the 10-year evolution of disability prevalence in elderly community dwellers and related factors. METHODS: Two generations of subjects aged 75 to 84, participants in the PAQUID (Personnes Agées QUID) cohort were compared. The first generation included 1496 subjects (born between 1903 and 1912) and the second 910 subjects (born between 1913 and 1922). Three domains of disability were assessed: mobility, Activities of Daily Living (ADL) and Instrumental ADL (IADL). Logistic regressions were used to explain the effect of generation on disability, controlling for sociodemographic characteristics, impairment, life-style, medical care, and social support. RESULTS: The percentage of subjects fully independent increased from 13.5 to 23.3% (p < 0.001). A large decline in disability prevalence independent of the controlled factors was observed for mobility in both genders [Odds Ratio for the second generation (OR(G2)) = 0.48, 95% CI 0.38-0.60]. When adjusting for age and education, the risk of IADL disability was significantly lower in women in the second generation (ORG2 0.61, 95% CI 0.49-0.77), and the generation effect was strengthened when adjusting for the other covariates, but unchanged in men (ORG2 1.09, 95% CI 0.81-1.48). There was no significant change for ADL. CONCLUSIONS: A significant decline in disability prevalence was observed over 10 years, which was not explained by the selected covariates. These aggregate changes differed by gender, education, and the domain of disability considered.

Activities of Daily Living↗
PubMed2002

Comparison of chloride- and hydride-generation for quantitation of germanium by headspace solid-phase microextraction-inductively coupled plasma-mass spectrometry.

Chloride- and hydride-generation headspace solid-phase microextraction (SPME) techniques have been compared for the detection of trace amounts of germanium by inductively coupled plasma time-of-flight mass spectrometry (ICP-TOFMS). The conditions for generation of germanium chloride, including acid type and concentration, effect of sodium chloride and extraction time, were investigated. Detection limits of 20 and 92 pg mL(-1) and precisions of 18% (n=11) and 9.7% (n=11) were achieved for chloride and hydride generation, respectively, at a concentration of 10 ng mL(-1). The generated germanium chloride and hydride species identities were characterized and confirmed as GeCl(4) and GeH(4) by use of electron-impact ionization mass spectrometry. Chloride generation coupled with SPME sampling and ICP-TOFMS detection resulted in twofold enhancement of sensitivity compared to GeH(4)and detection limits for continuous hydride generation were 20-fold better than reported atomic fluorescence data.

Journal Article↗
PubMed2003

Investigation of the direct hydride generation nebulizer for the determination of arsenic, antimony and selenium in inductively coupled plasma optical emission spectrometry.

A direct hydride generation nebulizer (DHGN) was explored for introduction of the sample in inductively coupled plasma-optical emission spectrometry (ICP-OES) using radially viewed mode. This simple hydride generation system was constructed in our laboratory and requires similar plasma operating conditions to conventional nebulizer-spray-chamber arrangements. This work was focused on the optimization of the operating conditions for hydride generation and evaluation of the main analytical figures of merit for the determination of As, Sb and Se. The excitation conditions of the ICP-OES instrument operated with the DHGN were also explored. Results showed that the analytical performance of the new system for the determination of As, Sb and Se was superior to that of conventional nebulization systems. The DHGN also enabled the determination of elements that do not form volatile hydrides, but with less sensitivity than conventional nebulization systems. Evaluation of the plasma robustness showed that gases generated in hydride generation do not significantly affects the plasma discharge. Similar to conventional hydride generation techniques, analysis with DHGN was susceptible to non-spectroscopic interferences produced by transition metals. Finally, the utility of the DHGN in practical ICP-OES studies was demonstrated in the determination of trace elements in an oyster tissue standard reference material.

Animals↗
PubMed2004

Force generation by recombinant myosin heads trapped between two functionalized surfaces.

Fluorescence resonance energy transfer measurements have revealed that the lever-arm domain of myosin swings when it hydrolyzes Mg-ATP. It is generally accepted that this swing of the lever arm of myosin is the molecular basis of force generation. On the other hand, the possibility that the force might be generated at the interface between actin and myosin cannot be ignored. However, there is a third possibility, namely, that myosin itself generates force without actin. Thus, using recombinant subfragment 1 molecules of Dictyostelium myosin II that were trapped between two functionalized surfaces of a surface-force apparatus, we determined whether myosin itself could actually generate force. Here, we report that, despite the absence of actin, myosin heads themselves have a capacity to generate a force (at least approximately 0.2 pN/molecule) that is coupled to the structural changes. Although the role of actin should not be neglected because muscle physiologically shortens as a result of the interaction between actin and myosin, in this work the focus is on the question of whether the catalytic domain of myosin has the capacity to generate force.

Adenosine Triphosphate↗
PubMedDate not supplied

Signaling through CD40 enhances cytotoxic T lymphocyte generation by CD8+ T cells from mice bearing large tumors.

Recent studies have demonstrated the importance of CD40/CD154 (CD40L) interactions for the generation of cell-mediated antitumor immune responses. Here we show that signaling via CD40 (through the use of the activating anti-CD40 mAb, IC10) can actually promote the in vitro generation of CTL activity by CD8+ splenic T cells from mice bearing a large MOPC-315 tumor. Anti-CD40 mAb had to be added at the initiation of the stimulation cultures of tumor-bearing splenic cells in order to realize fully its potentiating activity for cytotoxic T lymphocyte (CTL) generation, suggesting that signaling through CD40 is important at the inductive stage of antitumor cytotoxicity. Moreover, anti-CD40 mAb was found to enhance the expression of the B7-2 (CD86) and, to a lesser extent, the B7-1 (CD80) costimulatory molecules on B220+ cells (i.e., B cells), and B7-2 and, to a lesser extent, B7-1 molecules played an important role in the potentiating effect of anti-CD40 mAb for CTL generation by tumor-bearer splenic cells. Furthermore, B220+ cells were found to be essential for the potentiating effect of anti-CD40 mAb, as depletion of B220+ cells at the inductive stage completely abrogated the ability of anti-CD40 mAb to enhance CTL generation. Thus, signaling through CD40 enhances CTL generation by CD8+ T cells from tumor-bearing mice by a mechanism that involves the up-regulation of B7-2 and, to a lesser extent, B7-1 expression on B220+ cells.

Animals↗
PubMed2006

Stability of transgene integration and expression in subsequent generations of doubled haploid oilseed rape transformed with chitinase and beta-1,3-glucanase genes in a double-gene construct.

A double-gene construct with one chitinase and one beta-1,3-glucanase gene from barley, both driven by enhanced 35S promoters, was transformed into oilseed rape. From six primary transformants expressing both transgenes 10 doubled haploid lines were produced and studied for five generations. The number of inserted copies for both the genes was determined by Southern blotting and real-time PCR with full agreement between the two methods. When copy numbers were analysed in different generations, discrepancies were found, indicating that at least part of the inserted sequences were lost in one of the alleles of some doubled haploids. Chitinase and beta-1,3-glucanase expression was analysed by Western blotting in all five doubled haploid generations. Despite that both the genes were present on the same T-DNA and directed by the same promoter their expression pattern between generations was different. The beta-1,3-glucanase was expressed at high and stable levels in all generations, while the chitinase displayed lower expression that varied between generations. The transgenic plants did not show any major impact on fungal resistance when assayed in greenhouse, although purified beta-1,3-glucanase and chitinase caused retardment of fungal growth in vitro.

Blotting, Western↗
PubMed1999

Efficient object scatter correction algorithm for third and fourth generation CT scanners.

X-ray photons which are scattered inside the object slice and reach the detector array increase the detected signal and produce image artifacts as "cupping" effects in large objects and dark bands between regions of high attenuation. The artifact amplitudes increase with scanned volume or slice width. Object scatter can be reduced in third generation computed tomography (CT) geometry by collimating the detector elements. However, a correction can still improve image quality. For fourth generation CT geometry, only poor anti-scatter collimation is possible and a numeric correction is necessary. This paper presents a correction algorithm which can be parameterized for third and fourth generation CT geometry. The method requires low computational effort and allows flexible application to different body regions by simple parameter adjustments. The object scatter intensity which is subtracted from the measured signal is calculated with convolution of the weighted and windowed projection data with a spatially invariant "scatter convolution function". The scatter convolution function is approximated for the desired scanner geometry from pencil beam simulations and measurements using coherent and incoherent differential scatter cross section data. Several examples of phantom and medical objects scanned with third and fourth generation CT systems are discussed. In third generation scanners, scatter artifacts are effectively corrected. For fourth generation geometry with poor anti-scatter collimation, object scatter artifacts are strongly reduced.

Algorithms↗
PubMed1999

Generators of brain electrical activity in patients with Wilson's disease.

Electroencephalographic (EEG) generators were investigated in 13 patients suffering from hepatolenticular degeneration with and without neurological symptoms and in 13 healthy subjects for comparison by the use of FFT approximation. Quantitative assessment of motor deficits and psychiatric disturbances was correlated with EEG features. We found mainly an increase in delta activity, a decrease in alpha activity combined with a more posterior localisation of the EEG generators in the delta band and a more anterior one in the alpha band in patients compared with healthy controls. The localisation of the EEG generators in the patients with clinical apparent neurological symptoms were in all frequency bands more superficial compared with controls and patients without neurological symptoms. With longer duration of the disease, the lower the premorbid intelligence the more posterior was the delta EEG generator localised. Although the alpha EEG generator was more anteriorly localised with longer duration of the disease and more severe cognitive deficits, it was more superficial with more pronounced psychiatric symptoms, more severe cognitive deficits, lower premorbid intelligence and more pronounced motor disabilities. With more pronounced psychiatric symptoms and cognitive deficits, the beta EEG generator was more anteriorly localised. The present study demonstrated that a significant deviant EEG pattern exists between patients with and without clinical neurological symptoms and that stage-dependent alterations in psychiatric symptoms and cognitive ability are reflected on the EEG.

Adult↗
PubMed1999

The selective increase or decrease of organellar DNA in generative cells just after pollen mitosis one controls cytoplasmic inheritance.

Organellar DNA in mature pollen grains of eight angiosperm species (Actinidia deliciosa Lindl., Antirrhinum majus L., Arabidopsis thaliana (L.) Heynh., Medicago sativa L., Musa acuminata Colla, Pelargonium zonale (L.) L'Hér, Petunia hybrida Vilm. and Rhododendron mucronatum (Blume) G. Don, in which the modes of organellar inheritance have been determined genetically, was observed by fluorescence microscopy using Technovit 7100 resin sections double-stained with 4',6-diamidino-2-phenylindole (DAPI) and 3,3'-dihexyloxacarbocyanine iodide (DiOC(6)). The eight species were classified into four types, based on the presence or absence of organellar DNA in mature generative cells: namely (1) type "m+p+", which has both mitochondrial and plastid DNA (P. zonale), (2) type "m+p-", which only has mitochondrial DNA (M. acuminata), (3) type "m-p+", which only has plastid DNA (A. deliciosa, M. sativa, R. mucronatum), and (4) type "m-p-", which has neither mitochondrial nor plastid DNA (A. majus, A. thaliana, P. hybrida). This classification corresponded to the mode of organellar inheritance determined by genetic analysis. The presence or absence of mitochondrial and plastid DNA corresponded to paternal/biparental inheritance or maternal inheritance of the respective organelle, respectively. When organellar DNA was present in mature generative cells (m+ or p+), the DNA content of the organelles in the generative cells started to increase immediately after pollen mitosis one (PMI). In contrast, the DNA content of organelles in generative cells decreased rapidly after PMI when organellar DNA was absent from mature generative cells (m- or p-). These results indicate that the modes of inheritance (paternal/biparental inheritance or maternal inheritance) of mitochondria and plastids are determined independently of each other in young generative cells just after PMI.

Cytoplasm↗
PubMed2004

Fasciola hepatica: the developmental patterns of redial generations in naturally infected Galba truncatula.

A retrospective study on 1,211 snails naturally infected with Fasciola hepatica in central France was carried out to determine the numbers of full-grown sporocysts from which infections derived, to specify the developmental patterns of redial generations (normal or abnormal) and to count live and free rediae. In the department of Haute Vienne (siliceous subsoils), most snails showed single-sporocyst infections, with normal (46.3%) or abnormal (33.9%) development of redial generations. Two-sporocyst infections were scarcer (a total of 10.6%), while snail co-infections with F. hepatica and Paramphistomum daubneyi (8.0%) were found since 1996. In the department of Indre (calcareous subsoils), single-sporocyst infections showing normal development of rediae were the most numerous (58.0%), while the frequency of single-sporocyst infections with abnormal development was strongly decreased (4.3%). Two-sporocyst infections (with normal development of generations) and co-infections with F. hepatica and P. daubneyi slightly increased in frequency. The redial burdens found in snails collected from the department of Indre were significantly higher than those noted in snails originating from the department of Haute Vienne, whatever the type of snail infection; and these increases in numbers especially concerned the rediae of the second and subsequent generations. The results might be explained by the lower calcium ion content (7-23 mg/l) present in waters from the department of Haute Vienne which would induce a slower growth of infected snails (the shell height of adults scarcely reached 8 mm) and, consequently, would create barely favourable conditions for the development of the first rediae of the first generation within snails. However, the quality of the diet provided as food for snails and its influence on the development of redial generations cannot be excluded.

Animals↗