Extraneous fibre traces brought by river water - A case study.

The fibre traces on a young victim found underwater were mostly single fibre traces besides small amounts of fibre collectives indistinguishable from his parents clothes (mainly wool). Most of those single fibre traces were blue-grey polyester fibres showing tiny differences among each other. They were unexpected according to known population fibre studies. One year after the victim's discovery experiments were conducted to evaluate the possible contamination with fibres from river water. A small amount of extraneous fibres were collected among which blue and grey-black cotton and man-made (mainly polyester) fibres. All man-made fibres were single fibre traces and small fibre collectives were only observed for cotton. These results confirmed the frequent occurrence of blue and grey-black cotton fibres as background, but also highlighted the possible contamination with single blue and grey-black man-made fibres from river water. No wool was found, strengthening the significance of the wool fibre collectives present on the victim.

A study of black fleece garments: Can fleece fibres be recognized and how variable are they?

Fleece garments are very popular nowadays. This is reflected in forensic fibre cases where fleece garments and especially black colored items are frequently encountered. For this study 201 black and dark colored fleece garments were collected from co-workers, friends, family and shops. The constituent fibres were analyzed with common methods used in forensic fibre analyses: microscopy (bright field, polarized light, fluorescence); microspectrophotometry (MSP-visible range); infrared spectroscopy (FTIR) and comparison microscopy. Almost all fleece fabrics were made of 100% polyester fibres. The most abundant fibre type involved polygonal polyester fibres. The appearance of typical fleece-features was explored. It was found that fleece fibres would shed easily, resulting in many long polyester fibres. In many cases these fleece fibres showed typical "mushroom-ends" and in some cases a few thicker fibres that originated from the inner "base layer" of the fleece fabric were also found providing a second fibre type that can be lost from fleece fabrics. Most of the black fleece fabrics could be discriminated with the analytical techniques, the discriminating power DP was found to be 0.9985. This was despite the fact that most of the absorption spectra showed similar features in the visible range. They were denominated as TYPE 1 MSP-spectra and displayed 2 absorption bands at 450 nm and 600 nm.

Fibre persistence on immersed garment - Influence of water flow and stay in running water.

The persistence of fibre traces is a critical factor in the evaluation of fibre findings in forensic casework. Water can play a major role in affecting fibre persistence as a lot of fibre traces can get lost after washing incriminated garments, after rainfall over the victim's body or after immersion of the victim in water. The influence of immersion in standing water on fibre persistence was previously studied in our laboratory on various knitted recipient fabrics. The present study is focused on the persistence of target fibres on immersed cotton T-shirts through an immersion/stay/emersion process in running water (from 1h up to 7h), simulated in laboratory (~0.4l/s, gentle water flow conditions) and in real conditions (~2000l/s, medium water flow conditions). A gentle water flow slightly affects fibre persistence, which remains more or less constant over time, regardless of the duration of the stay in water. No rapid loss is observed during immersion in real conditions, including a medium water flow and boat activity. The fibre persistence in running water seems to depend mainly on the immersion step and also, in case of a medium water flow, on the stay in water with a linear loss over hours.

Fibre persistence on immersed garment-Influence of knitted recipient fabrics.

The persistence of fibre traces is a critical factor in the evaluation of fibre findings in forensic casework. Many persistence studies have examined the loss of fibre traces on living subjects or on bodies exposed to open-air conditions but none of them have ever considered bodies in underwater conditions. This first part of a larger study focuses on the persistence of transferred fibres on various recipient garments during an immersion/emersion process as the common step to all casework involving underwater conditions. A smooth polyester garment leads to weak persistence values around 20%, while higher persistence values, ranging between 80% and 90%, are obtained for more structured and textured garments (cotton T-shirts, fleece and acrylic pullovers). More textured garments are thus less affected by the immersion/emersion process and fibre findings are closer to their initial amount and distribution before immersion. The amount of protruding fibres and the density of the rough fibrous network at the surface of the recipient garment are both key factors that increase the persistence value. Therefore, these factors should be taken into account when evaluating fibre evidence recovered on immersed bodies.

Dichroism measurements in forensic fibre examination. Part 2 - dyed polyamide, wool and silk fibres.

A number of dyed polyamide, wool and silk samples were examined with plane polarized light on their dichroic behavior by optical light microscopy (OLM) and microspectrophotometry with plane polarized light (MSP-PPL). It was found that most of these acid dyed peptidic fibres possess dichroism, but these are weaker than the effects previously described for polyester fibres. The small effects may be not observed, especially for wool, but these can be measured using MSP-PPL. In the three peptidic fibre classes, for the first time, a so called "inverse dichroism" is observed which appears in the absorption spectra as a hyperchromic effect.

Dichroism measurements in forensic fibre examination Part 1--Dyed polyester fibres.

One hundred and twenty dyed polyester samples were examined with plane polarized light on their dichroic behaviour by optical light microscopy (OLM) and microspectrophotometry in the visible range (MSP Vis). It was found that most of these disperse dyed polyester fibres possess a strong dichroism, which fall into two broad categories. Either a decrease of intensity (hypochromic effect) or a change of hue (hypsochromic or bathochromic shift of absorption bands) is noted. These dichroic effects are related to the orientation of the dye structure with respect to the polymer chains.

Chronobiology of Plasmodium chabaudi chabaudi: analysis of hourly recorded total and differential parasitaemia during a schizogonic cycle.

Detailed total and differential parasitaemia curves of asexual Plasmodium chabaudi chabaudi erythrocytic stages were recorded and analysed. Female, inbred, CBA/Ca mice were infected with the virulent IP-PC1 strain after in vitro synchronization of the parasites. Thin blood smears were made on an hourly basis, and the total and differential parasitaemia of ring forms, trophozoites and schizonts were counted after Giemsa staining. These curves reveal information that remains hidden when less detailed curves are examined: the duration and periodicity of the schizogonic cycle, the existence of a plateau, indications of a schizont withdrawal from the peripheral blood, the timing of the rise of the parasitaemia at each schizogony, and the invasion rate of the merozoites. In the perspective of developing a rational and efficient strategy for chronotherapy of malaria, such information should be taken into account.

Immunogenization of a murine T-cell lymphoma via transfection with interferon-gamma.

Tumor cell variants were derived from the BW5147 T-cell lymphoma that differ in major histocompatibility complex (MHC) class I antigen expression, tumorigenicity and metastatic potential. In general, increased H-2Kk expression was found to be correlated with a reduced tumorigenicity and spontaneous metastasis. CD8+ T cells were identified in the immune recognition of such variants, implicating a role for H-2Kk in the presentation of tumor-associated antigens. In the present study, H-2Kk+ BW variants were transfected with a gene encoding interferon-gamma (IFN-gamma), a potent inducer of MHC class I expression. The resulting transfectants exhibited an increased expression of H-2Kk and concomitantly an inability to generate visible tumors and a reduced metastatic capacity. Furthermore, immunization with the IFN-gamma transfectants resulted in an increased generation of cytotoxic T lymphocytes (CTLs) that lysed both the transfectants and the parental tumor cells. Based on these results, vaccinations with the IFN-gamma transfectants were performed against the parental tumor cells. The results clearly demonstrated that such vaccinations reduced significantly the tumorigenicity and metastatic capacity of the parental tumor cells. Hence, in this tumor model, IFN-gamma gene transfection provides a means to immunogenize H-2Kk+ BW tumor cells.

Isolation and characterization of different forms of thioredoxins from the green alga Acetabularia mediterranea: identification of an NADP/thioredoxin system in the extrachloroplastic fraction.

A procedure has been developed for the simultaneous purification to apparent homogeneity of chloroplast thioredoxins f and m, and nonchloroplast thioredoxin h, from the green alga Acetabularia mediterranea. In the chloroplast fraction, three thioredoxins were isolated: one f type thioredoxin (Mr 13.4 kDa) and two m type thioredoxin forms (Mr of 12.9 and 13.8 kDa). A Western blot analysis of crude and purified chloroplast thioredoxin preparations revealed that Acetabularia thioredoxin m was immunologically related to its higher-plant counterparts whereas thioredoxin f was not. In the nonchloroplast fraction, a single form of thioredoxin h (Mr 13.4 kDa) and its associated enzyme NADP-thioredoxin reductase (NTR) were evidenced. Acetabularia NTR was partially purified and shown to be an holoenzyme composed of two 33.0-kDa subunits as is the case for other plant and bacterial NTRs. Similarity was confirmed by immunological tests: the algal enzyme was recognized by antibodies to spinach and Escherichia coli NTRs. Acetabularia thioredoxin h seemed to be more distant from higher-plant type h thioredoxins as recognition by antibodies to thioredoxin h from spinach and wheat was weak. The algal thioredoxin h was also slightly active with spinach and E. coli NTRs. These results suggest that in green algae as in the green tissues of higher plants the NADP and chloroplast thioredoxin systems are present simultaneously, and might play an important regulatory role in their respective cellular compartments.

Experimental analysis of the metastatic phenotype of malignant leukocytes.

The metastatic phenotype (M+) is determined by the expression of the invasive (I+) and growth (G+) phenotypes at various sites along the metastatic pathway. The G, I and M phenotypes are not confined to tumor cells and may be expressed by normal cells, such as leukocytes, under certain physiological conditions. The study of the I and M phenotypes of leukocytes may yield valuable information on common mechanisms, underlying invasion and metastasis of normal and malignant cells. In this review we summarize experimental approaches that were developed for the analysis of the I and M phenotypes of normal and malignant leukocytes.

Association between MHC class I antigen expression and malignancy of murine T lymphoma variants.

Tumor cell variants were derived from an AKR T-cell lymphoma cell line (BW5147, H-2k haplotype). These variants differed in their malignant potential and in their membrane expression of class I MHC antigens. High tumorigenic and spontaneous metastatic capacity was found to be predominantly associated with a decrease of H-2Kk class I major histocompatibility complex (MHC) antigen expression. In contrast, high experimental metastatic capacity correlated strongly with an increased H-2Dk antigen expression. The in vitro invasive potential and the LFA-1 expression of the BW variants showed no correlation with the differential MHC antigen expression and the differential metastatic and tumorigenic capacity of the BW variants. Furthermore, the susceptibility of the BW 5147 variants to TNF and NK-mediated cytotoxicity was not related to the differential metastatic potential and the expression of the class I MHC antigens.

The molecular mechanism of circadian rhythms.

The endogenous and ubiquitous circadian rhythms (CR) are not understood in molecular terms, in spite of recent interesting advances. They concern, on one hand, protein synthesis, of which a small fraction--possibly a single protein--, formed on cytosolic ribosomes, may be required on each 24 h cycle. On the other hand, the per gene, involved in the control of CR in drosophila has been found to direct the synthesis of 2 (or 3) proteoglycans. Several models have been put forward in order to explain CR generation. Considering the complexity of the cell's organization and the occurrence of partial arrhythmicity, CR generation might result from the integration of a few physiological and metabolic pathways normally involving at least one feed-back loop. Sequentiality would be inherent to the kinetics of both the metabolic pathways and translocators located in the membranes of the various compartments; as a consequence, the peaks of the oscillatory activities would be positioned at particular phase points relative to others. Proteoglycans (or other proteins modified post-transcriptionally) could be involved in the operation of rhythms in controlling not only some plasmalemma (as proposed by Yu et al., 1987) but also intracellular membranes. Finally, reversible enzyme modification occurring on each 24 h cycle could be critically important in circadian rhythms generation.

Masking in plants.

Circadian rhythms in plants are liable to masking, i.e. alterations by environmental influencing agents. Experiments have been reported for both positive and negative masking, attributed to a Zeitgeber which may either increase or decrease the amplitude of a circadian rhythm (CR). In some instances, the CR may even be unexpressed. This inhibition, however, may be alleviated by synchronizing agents. Reports are also available for changes in the shape or pattern of an oscillation. The latter may be prevented, at least in Acetabularia in certain conditions, by a phytohormone antagonist. Masking may also be brought about by water stress, relative humidity, bacterial infection and alteration in the relative direction of the gravitational force. Finally, subjecting plants to constant conditions, particularly continuous light, alters the physiological state of the organism.

Temporal morphology and cap formation in Acetabularia--I. Light-dark cycle perturbations.

Cap formation, a major developmental process in the alga Acetabularia, is influenced by a single perturbation of the entraining light-dark schedule and thus, presumably, of the circadian rhythms. This perturbation is brought about several weeks before cap formation, the most conspicuous expression of morphogenesis in Acetabularia. The effect is more pronounced on cap formation than on growth. It varies in importance with the circadian time at which the perturbation was brought about. The effect is dependent on the developmental state of the alga: transfer carried out during the logarithmic phase of growth produces a delay whose importance decreases with time. When carried out during the phase of slow terminal growth, the transfer induces a transitory acceleration of cap formation. When the algae approach their final length, no effect is elicited. Photoperiodism seems to be involved.

Temporal morphology and cap formation in Acetabularia--II. Effects of morphactin and auxin.

In order to support the hypothesis that circadian rhythms are implicated in cap formation, experiments were undertaken on the possible time-dependency of the effects of (a) a competitive inhibitor of auxins, morphactin and (b) of auxin (IAA). It was found that: (i) the inhibitory effect of morphactin varies dramatically with the time at which the several weeks' treatment was first begun; (ii) the maximum inhibition varies with development and decreases with time; (iii) IAA accelerates cap formation when the algae are submitted to IAA during the exponential growth phase; the effect is time dependent and decreases with time; (iv) IAA first applied on smaller algae has a transient inhibitory effect which is time dependent; (v) anucleate fragments also respond differentially to an IAA treatment begun at several times in the 24-hr cycle, most clearly when newly formed mRNA have been accumulated and (vi) the effect of iAA is not cumulative with that of a LD shift; that of morphactin is not, or only slightly, improved by a LD shift.

Changes in the cyclic AMP content during growth and development of Acetabularia.

The 3',5'-adenosine monophosphate (cyclic-AMP) content of the unicellular alga Acetabularia has been examined at various developmental stages. It has been found that very young algae, less than 10mm in length, have a high cAMP content [more than 7 pmoles per 100 mg wet weight (WW)], but that with the growth of the algae, the cAMP content decreases rapidly, reaching the low level of 0.5--1.0 pmoles per 100mg WW. The cAMP content remains at this level until cap differentiation, after which an increase in cAMP content accompanies cap enlargement. It has been shown that these results are unlikely to be affected by changes in the cAMP content induced by variations in circadian rhythm. Treatment with theophylline (2.10(-3) M), a phosphodieterase inhibitor, results in an increase in the cAMP content and delays growth and cap formation. Experiments on the effects of theophylline upon the circadian rhythm of oxygen evolution have shown that the continuous presence of theophylline in the culture medium does not induce a phase shift in the rhythm. The cAMP content of anucleate Acetabularia shows development stage variations parallel to that of the whole algae.