New insights on lake sediment DNA from the catchment: importance of taphonomic and analytical issues on the record quality

Over the last decade, an increasing number of studies have used lake sediment DNA to trace past landscape changes, agricultural activities or human presence. However, the processes responsible for lake sediment formation and sediment properties might affect DNA records via taphonomic and analytical processes. It is crucial to understand these processes to ensure reliable interpretations for “palaeo” studies. Here, we combined plant and mammal DNA metabarcoding analyses with sedimentological and geochemical analyses from three lake-catchment systems that are characterised by different erosion dynamics. The new insights derived from this approach elucidate and assess issues relating to DNA sources and transfer processes. The sources of eroded materials strongly affect the “catchment-DNA” concentration in the sediments. For instance, erosion of upper organic and organo-mineral soil horizons provides a higher amount of plant DNA in lake sediments than deep horizons, bare soils or glacial flours. Moreover, high erosion rates, along with a well-developed hydrographic network, are proposed as factors positively affecting the representation of the catchment flora. The development of open and agricultural landscapes, which favour the erosion, could thus bias the reconstructed landscape trajectory but help the record of these human activities. Regarding domestic animals, pastoral practices and animal behaviour might affect their DNA record because they control the type of source of DNA (“point” vs. “diffuse”).

Coupling indicators and lumped-parameter modeling to assess suspended matter and soluble phosphorus losses

For ecological and economic issues, evaluating the environmental fate of dissolved and suspended matter in catchments and river ecosystems still remains a challenge for the preservation and management of natural resources. Models are useful tools and may help to cope with this challenge, and especially to define the relationships between the state of natural systems and land and river management/uses. As it is difficult - even impossible - to carry out experiments on natural systems such as catchments, models are also useful to test hypotheses about the underlying processes acting on dissolved and suspended losses. We propose an innovative approach to achieve these objectives. By coupling environmental indicators and lumped modeling, this study aims to develop a conceptual and general framework to evaluate and test the functions that drive particulate and dissolved matter flows at the catchment and landscape scales, while respecting the constraint of parsimony for the number of model parameters. Calculated suspended matter (SM) and soluble reactive phosphorus (SRP) losses agreed well with field data. ²¹⁰Pb_ex (excess Pb) activities in core sediments were also compared to those of ²¹⁰Pb_ex calculated from the filling of the reservoir. Our models are parsimonious and this does not impair their accuracy in reproducing recorded outflows or evaluating the sedimentation processes associated to particulate outflows. Considering the adequacy of our models, we validate the hypothesis that river bank erosion and water table behavior are the driving processes that govern losses of particulate and solute forms of P, in the studied extensive agriculture conditions.

Comparison of Apheresis and Other Methods for Separation and Purification of Hemopoietic Stem Cells: Initial Experience with a Blood Buffy Coat Model for the use of Autologous Bone Marrow Transplantation

With an increasing number of bone marrow transplantations (BMT) being contemplated in leukemia and cancer patients, it is prudent for blood banks to develop a suitable program within their resources for harvesting, purifying and freezing bone marrow stem cells. In order to do this, initially a prototype has been developed involving buffy coat model (BC) using normal donor blood. Centrifugation, sedimentation and machine apheresis methods were separately evaluated leading to a combined and sequential handling procedure. Blood was passed through a cell separator resulting collection of BC with 90% reduction of the volume showing 80% recovery of total leucocytes and 87% yield of mononuclear cells. Following centrifugation the cells with DMSO were frozen in a controlled freezing system and stored in liquid nitrogen. After thawing 94% cells were recovered with 93% viability. The initial experience gained in the model system could be incorporated in autologous BMT program in patients but requires modifications for improved results; the latter will be described separately.

[Fetomaternal anti-RH3, -4 (anti-E and anti-c) rhesus isoimmunization: a case report]

Hemolytic disease of the newborn caused by maternal isoimmunization has been decreasing over the past 10 years because of prophylactic treatment with anti-RH1 (anti-D) immunoglobulin. Nevertheless, there is an increase in the incidence of both relative and absolute numbers of non-RH1 red-cell maternofetal isoimmunizations, essentially anti-RH4 (anti-c), anti-RH3 (anti-E), and anti-Kell. In 8 to 14% of cases, multispecificity antibodies are present, the most common combination being the association of anti-RH3 and -4. Despite absence of specific prophylactic therapy, anti-RH4 isoimmunization could be as severe as anti-RH1 ; as for anti-RH3, it is usually associated with mild to moderate clinical manifestations. Nevertheless, there are few publications on anti-RH3, -4 maternofetal isoimmunization with a bias toward the most severe cases being reported. We report here a case of nonsevere maternofetal anti-RH3, -4 isoimmunization complicated with severe hyperbilirubinemia and delayed profound anemia. Hyperbilirubinemia was controlled using intensive phototherapy. Although anemia was absent at birth, it appeared progressively with a nadir at 7.8 g/dL at 1-month postnatal age. Blood counts were monitored for 3 months but the patient did not require red blood cell transfusion. This report underlines the need for a prolonged and rigorous pediatric follow-up of children born in the context of maternofetal isoimmunization after the acute neonatal period. Furthermore, it stresses the necessity of DAT testing in all pregnant women, even those who are RH1-positive.

Endogenous retroviruses of sheep: a model system for understanding physiological adaptation to an evolving ruminant genome

Endogenous retroviruses (ERVs) are present in the genome of all vertebrates and are remnants of ancient exogenous retroviral infections of the host germline transmitted vertically from generation to generation. Sheep betaretroviruses offer a unique model system to study the complex interaction between retroviruses and their host. The sheep genome contains 27 endogenous betaretroviruses (enJSRVs) related to the exogenous and pathogenic Jaagsiekte sheep retrovirus (JSRV), the causative agent of a transmissible lung cancer in sheep. The enJSRVs can protect their host against JSRV infection by blocking early and late steps of the JSRV replication cycle. In the female reproductive tract, enJSRVs are specifically expressed in the uterine luminal and glandular epithelia as well as in the conceptus (embryo and associated extraembryonic membranes) trophectoderm and in utero loss-of-function experiments found the enJSRVs envelope (env) to be essential for conceptus elongation and trophectoderm growth and development. Collectively, available evidence in sheep and other mammals indicate that ERVs coevolved with their hosts for millions of years and were positively selected for biological roles in genome plasticity and evolution, protection of the host against infection of related pathogenic and exogenous retroviruses, and placental development.

Coevolution of endogenous betaretroviruses of sheep and their host

Sheep betaretroviruses offer a unique model system to study the complex interaction between retroviruses and their host. Jaagsiekte sheep retrovirus (JSRV) is a pathogenic exogenous retrovirus and the causative agent of ovine pulmonary adenocarcinoma. The sheep genome contains at least 27 copies of endogenous retroviruses (enJSRVs) highly related to JSRV. enJSRVs have played several roles in the evolution of the domestic sheep as they are able to block the JSRV replication cycle and play a critical role in sheep conceptus development and placental morphogenesis. Available data strongly suggest that some dominant negative enJSRV proviruses (i.e. able to block JSRV replication) have been positively selected during evolution. Interestingly, viruses escaping the transdominant enJSRV loci have recently emerged (less than 200 years ago). Thus, endogenization of these retroviruses may still be occurring today. Therefore, sheep provide an exciting and unique system to study retrovirus-host coevolution. (Part of a multi-author review).

Temporal evolution of urban wet weather pollution: analysis of PCB and PAH in sediment cores from Lake Bourget, France

In order to evaluate the historical impact of urban stormwater runoff on a lacustrine environment, eight sediment cores were collected in October 2006 in Lake Bourget (Savoie, France). Sediment samples were analysed for polycyclic aromatic hydrocarbons (PAH) and polychlorobyphenyls (PCB) in order to correlate the vertical profiles of contamination and the evolution of the urbanisation on the watershed for the last 100 years. Overall, we observe that vertical profiles of PCB and PAH concentrations in Lake Bourget are showing a downward trend, probably resulting from the pollution control measures. Concentrations of PCB and PAH measured in surface sediments are approximately 5-10 fold less than maximal concentrations found in the cores. Maximal PAH concentrations were found at the bottom of the cores ( approximately 40 cm) which approximately correspond to the beginning of the 20th century. Maximal PCB concentrations measured in cores L5 and L6 are respectively 850 and 790 microg/g dw (dryweight). The peak of PCB corresponds to the maximum of PCB production and consumption in the 1970s. In surface sediments total PCB concentrations range between 47 and 79 microg/kg dw. Those concentrations are particularly high compared to other values measured in lake sediments and highlight the problem of a local source of PCB contamination in the watershed. General trends were observed, yet the part of urban stormwater runoff in the total contamination could not be determined.

Coagulation patterns following haemoglobin-based oxygen carrier resuscitation in severe uncontrolled haemorrhagic shock in swine

Massive blood loss due to penetrating trauma and internal organ damage can cause severe haemorrhagic shock (HS), leading to a severely compromised haemostatic balance. This study evaluated the effect of bovine polymerized haemoglobin (Hb) (Hb-based oxygen carrier, HBOC) resuscitation on haemostasis in a swine model of uncontrolled HS. Following liver injury/HS, swine received HBOC (n= 8), Hextend (HEX) (n= 8) or no resuscitation (NON) (n= 8). Fluids were infused to increase mean arterial pressure above 60 mmHg and to reduce heart rate to baseline. At 4 h, the animals were eligible for blood transfusions. Prothrombin time (PT), activated partial thromboplastin time, fibrinogen, thromboelastography (TEG) and platelet function analyser closure time (PFA-CT) were compared by using mixed statistical model. At 4 h, blood loss (% estimated blood volume) was comparable for HBOC (65.5 +/- 18.5%) and HEX (80.8 +/- 14.4%) and less for NON (58.7 +/- 10.1%; P < 0.05). Resuscitation-induced dilutional coagulopathy was observed with HBOC and HEX, as indicated by reduced haematocrit, platelets and fibrinogen (P < 0.05). At 4 h, PT was higher in HEX than in HBOC groups (P < 0.01). In the early hospital phase, a trend to increased TEG reaction time and PFA-CT indicates that dilutional effects persist in HBOC and HEX groups. PFA-CT returned to baseline later with HBOC than with HEX (48 vs. 24 h) following blood transfusion. At 4 h, all surviving HEX animals (n= 3) required transfusion, in contrast to no HBOC (n= 7) or NON (n= 1) animals. In this severe uncontrolled HS model, successful resuscitation with HBOC produced haemodilutional coagulopathy less than or similar to that produced by resuscitation with HEX.

Viral particles of the endogenous retrovirus ZAM from Drosophila melanogaster use a pre-existing endosome/exosome pathway for transfer to the oocyte

Background

Retroviruses have evolved various mechanisms to optimize their transfer to new target cells via late endosomes. Here, we analyzed the transfer of ZAM, a retroelement from Drosophila melanogaster, from ovarian follicle cells to the oocyte at stage 9–10 of oogenesis, when an active yolk transfer is occurring between these two cell types.

Results

Combining genetic and microscopic approaches, we show that a functional secretory apparatus is required to tether ZAM to endosomal vesicles and to direct its transport to the apical side of follicle cells. There, ZAM egress requires an intact follicular epithelium communicating with the oocyte. When gap junctions are inhibited or yolk receptors mutated, ZAM particles fail to sort out the follicle cells.

Conclusion

Overall, our results indicate that retrotransposons do not exclusively perform intracellular replication cycles but may usurp exosomal/endosomal traffic to be routed from one cell to another.

[Blood product transfusion in the neonatal period]

Newborn infants in intensive care units, especially those born premature, are at particular risk for blood transfusion adverse effects. Aside improvements in the preparation of specific blood products for the neonatal period, such as multiple packed cells preparations from a single donor for multiple transfusions in premature infants, progress has involved prophylaxis of anemia of prematurity as well. Recombinant human erythropoietin has proven to be beneficial with high range evidence. Also, alternative methods have been proposed to compensate for the delay in the effect of rHuEPO, such as delayed clamping of umbilical cord at birth, or autologous placental blood transfusion. However, a better understanding of the indications of blood transfusion and the provision of practice guidelines may justify a re-evaluation of prophylactic strategies for anemia of prematurity.

Functional characteristics of a reverse transcriptase encoded by an endogenous retrovirus from Drosophila melanogaster

ZAM is an LTR-retrotransposon from Drosophila melanogaster that belongs to the genus errantivirus, viruses similar in structure and replication cycle to vertebrate retroviruses. A key component to its lifecycle is its reverse transcriptase which copies single-stranded genomic RNA into DNA. Here, we provide a detailed characterization of the enzymatic activities of the reverse transcriptase encoded by ZAM. When expressed in vitro, the reverse transcriptase domain associated with the RNase H domain encoded by the ZAM pol gene forms homodimers and displays an efficient RNA-dependent DNA-polymerase activity. It requires either Mg2+ or Mn2+ divalent cations, and works in basic pH, with a peak at around pH9. The so-called [RT-RH] polypeptide displays an optimal activity at 22 degrees C, a property that makes it well-adapted to the temperature of its host. This study contributes to our understanding of the general structures and functions of retroviral reverse transcriptases, a necessary process in the search for novel inhibitors.

La sortie de néonatalogie du grand prématuré : pour ne rien oublier

Key elements of the check list for neonatal discharge include: discharge discussion with parents, relation with maternal and child welfare assistants and family practitioner, scheduling of follow-up visits, request for insurance coverage, parental presence allowance, special education allowance, debriefing with nurses and nurses providers, clinical and biological appraisal, discharge prescription. For a former extremely premature baby, going home - often after a long hospitalization and a variety of pathologic problems - must be prepared and should not be decided in haste, not only for the baby and his/her parents, but also. for the neonatal staff!

A 300 year history of lead contamination in northern French Alps reconstructed from distant lake sediment records

Lead concentrations and isotopic ratios were measured along two well-dated sediment cores from two distant lakes: Anterne (2100 m a.s.l.) and Le Bourget (270 m a.s.l.), submitted to low and high direct human impact and covering the last 250 and 600 years, respectively. The measurement of lead in old sediment samples (>3000 BP) permits, in using mixing-models, the determination of lead concentration, flux and isotopic composition of purely anthropogenic origin. We thus show that since ca. 1800 AD the regional increase in lead contamination was mostly driven by coal consumption ((206)Pb/(207)Pb approximately 1.17-1.19; (206)Pb/(204)Pb approximately 18.3-18.6), which peaks around 1915 AD. The increasing usage of leaded gasoline, introduced in the 1920s, was recorded in both lakes by increasing Pb concentrations and decreasing Pb isotope ratios. A peak around 1970 ((206)Pb/(207)Pb approximately 1.13-1.16; (206)Pb/(204)Pb approximately 17.6-18.0) corresponds to the worldwide recorded leaded gasoline maximum of consumption. The 1973 oil crisis is characterised by a drastic drop of lead fluxes in both lakes (from approximately 35 to <20 mg cm(-2) yr(-1)). In the late 1980s, environmental policies made the Lake Anterne flux drop to pre-1900 values (<10 mg cm(-2) yr(-1)) while Lake Le Bourget is always submitted to an important flux (approximately 25 mg cm(-2) yr(-1)). The good match of our distant records, together and with a previously established series in an ice core from Mont Blanc, provides confidence in the use of sediments as archives of lead contamination. The integration of the Mont Blanc ice core results from Rosman et al. with our data highlights, from 1990 onward, a decoupling in lead sources between the high elevation sites (Lake Anterne and Mont Blanc ice core), submitted to a mixture of long-distance and regional contamination and the low elevation site (Lake Le Bourget), where regional contamination is predominant.

Use of hollow fiber membrane filtration for the removal of DMSO from platelet concentrates

It has been hypothesized that, in addition to freezing injury, some damage to platelets may result from the cell packing that occurs during removal of the cryoprotectant. This study examined DMSO removal by fluid exchange across hollow-fiber (HF) filters as an alternative to centrifugation. The DMSO solution with or without cell suspension was passed once through the filter. The optimum exchange during unloading of DMSO was determined by varying the flow rates in the external and internal compartments of the HF filter. Initially, buffered solutions of a 5% DMSO solution in the absence of platelets were pumped into the fibers and exchanged against PBS. The residual DMSO was determined by osmometry. The exchange of DMSO across the membrane was flow dependent and also influenced by the chemical nature of the HF fibers. No protocol using a reasonable rate flow through the fibers removed more than 95% of the DMSO in a single pass. The optimum protocol was achieved with polysynthane fibers with an internal flow rate of approximately 20 mi/min and an external flow rate of 100 ml/min. Subsequently, frozen/thawed platelet concentrates in DMSO were washed using centrifugation and compared to the HF filtration method. Platelet quality was assayed by flow cytometry, cell count, morphology and osmotic stress test. Both filtration and centrifugal washing techniques resulted in comparable morphological scores and numbers of discoid cells. When agents reducing platelet activation were added, platelet quality was improved after washing by either technique. The lower platelet osmotic response with HF filtration than with centrifugation while using activation inhibitors was attributed to the remaining amount of the inhibitors. All other parameters tested were similar. The expression of CD62P was equivalent with both techniques, and centrifugation did not activate platelets more than filtration contrary to what was originally anticipated. In conclusion, platelet quality was comparable after washing by either technique but hollow fiber filtration does remove cryoprotectant more rapidly than does centrifugation.

Expression of the Idefix retrotransposon in early follicle cells in the germarium of Drosophila melanogaster is determined by its LTR sequences and a specific genomic context

Retrotransposons are transcriptionally activated in different tissues and cell types by a variety of genomic and environmental factors. Transcription of LTR retrotransposons is controlled by cis-acting regulatory sequences in the 5' LTR. Mobilization of two LTR retroelements, Idefix and ZAM, occurs in the unstable RevI line of Drosophila melanogaster, in which their copy numbers are high, while they are low in all other stocks tested. Here we show that both a full-length and a subgenomic Idefix transcript that are necessary for its mobilization are present in the Rev1 line, but not in the other lines. Studies on transgenic strains demonstrate that the 5' LTR of Idefix contains sequences that direct the tissue-specific expression of the retroelement in testes and ovaries of adult flies. In ovaries, expression occurs in the early follicle and in other somatic cells of the germarium, and is strictly associated with the unstable genetic context conferred by the RevI line. Control of tissue-specific Idefix expression by interactions between cis-acting sequences of its LTR and trans-acting genomic factors provides an opportunity to use this retroelement as a tool for the study of the early follicle cell lineage in the germarium.

Human platelets activate porcine endothelial cells through a CD154-dependent pathway

BACKGROUND

Delayed xenograft rejection is associated with endothelial cell activation, platelet sequestration, and subsequent thrombosis. We evaluated whether human platelets could directly activate porcine endothelium (PEC), and if so, whether this was mediated by an interaction between platelet-bound CD154 and PEC CD40.

METHODS

Platelet activation was achieved by thrombin exposure and confirmed by evaluation of up-regulated CD62P and CD154. Co-incubation of platelets or D1.1 cells with PEC was performed, and PEC activation was evaluated by up-regulation of CD62E.

RESULTS

Co-incubation of resting platelets that lacked significant expression of CD62P and were void of CD154 did not activate PEC. In contrast, thrombin-activated human platelets expressing considerable amounts of both CD62P and CD154 induced PEC activation. This activation could be completely inhibited by coincubation with a humanized monoclonal antibody directed at human CD154 (hu5c8). Similarly, human D1.1 cells expressing CD154 were shown to activate PEC in a CD154-dependent manner.

CONCLUSION

Human CD154 expressed on activated human platelets or on T cells interacts with CD40 expressed on PEC leading to PEC activation. This interaction can be inhibited by a monoclonal antibody directed against CD154, suggesting that an interaction between human CD154 and PEC CD40 is at least in part responsible for PEC activation seen in delayed xenograft rejection. These data strengthen the rationale for the use of CD154-directed therapy in discordant xenotransplantation.

Endothelial and smooth muscle changes of the thoracic and abdominal aorta with various types of cryopreservation

BACKGROUND

There is a need for cryopreserved arterial allografts in vascular surgery. Vitrification was examined as an alternative to slow cooling. Function of endothelial and adjacent cells was evaluated in the thoracic and abdominal regions of the porcine aorta.

MATERIAL AND METHODS

Aortas from young pigs were harvested and cryopreserved with several treatments: slow cooling at 1 degrees C/min with 10% dimethyl sulfoxide (DMSO) and vitrification with a vitrification solution (VS), performed either in the presence (medium) or in the absence (air) of the cryoprotective medium surrounding the sample. Tetrazolium salt reduction and oxygen consumption were used to assess the mitochondrial activity of the endothelial cells and smooth muscle cells from the aorta.

RESULTS

Fresh aorta showed an increased function from below the aortic arch to the iliac branch. Exposure to cryoprotective solutions reduced significantly the oxygen consumption of the abdominal sections. Samples from the thoracic region had a better response to cryopreservation than those from the abdominal region. There was a significant reduction in tetrazolium salt reduction and oxygen consumption when the samples were cryopreserved immersed in the medium. Significant flaking of the endothelium was observed after vitrification and contributes generally to lower the function.

CONCLUSION

The thoracic region of the aortic wall was more tolerant to the preservation injury, and freezing with DMSO in air offered a better choice of preservation.

Frozen/thawed platelets: importance of osmotic tolerance and platelet subpopulations

Me2SO cryopreserved platelets circulate in vivo, reduce bleeding time, and have hemostatic properties but their functional recovery is only half that of the fresh material. Poor osmotic response is often reported as the cause of the freezing injury. Osmotic excursions on 1- and 5-day-old platelets have been studied. Platelets stored for 5 days have a lesser capability to regulate their volume particularly after an initial swelling. This is attributed to the reduction of discoid cell number, 80% vs 62% for 1-day-old and 5-day-old platelets, respectively. After freezing, hypotonic stress response is reduced from 86 to 39% for 1-day-old and 73 to 31% for 5-day-old platelets. This reduction in function is supported by a similar reduction of discoid cells from 80 to 40% for 1-day-old and 62 to 32% for 5-day-old platelets. The integrity of the cytoskeleton is critical for the osmotic response. Freezing recovery is significantly lowered in the presence of propylene glycol, which alters actin. This contrasts with the recovery of platelets treated with anti-aggregating agents. Platelets show a greater viability after freezing and thawing when PGI2 is added. It is postulated that freshly collected platelets, which are heterogeneous, contain populations of cells that are more sensitive to freezing than others. More tolerant cells remain discoid after freezing and are also less susceptible to storage lesions. Therefore, the maintenance of the integrity of the membrane and the cytoskeleton should be considered for the development of preservation methodologies.

Freezing injury of granulocytes during slow cooling: role of the granules

The granulocyte is an interesting model for studying the behavior of fragile cells at low temperature. A previous study suggested that during slow freezing the plasma membrane was not the primary site of injury and, as a corollary to this, we examined the damage occurring in the cytoplasmic compartment. The present study was designed to investigate the role of granules during cryoinjury of the granulocytes. Granulocytes were prepared from fresh blood and a population of granules was extracted by nitrogen cavitation. A graded freeze-thaw protocol was used to follow the release of beta-glucuronidase (beta-Glu), one of the hydrolytic enzymes present in granules. Granulocytes and granules were subjected to treatments simulating slow freezing conditions, and the release of beta-Glu was evaluated after exposure to increased hydrolytic enzymes and hypertonic salt concentration. It was found that, after thawing, granulocytes generally expressed more release than granules during graded freezing. The postthaw incubation period had no effect on enzyme release. Increase in salt concentration reduces beta-Glu activity. Direct exposure to hydrolytic enzymes produced similar injury on both granules and granulocytes, and salt combined with enzymes did not increase granule disruption. It is concluded that the effect of injured granules may be more apparent during rewarming when isotonicity is reestablished. Enzymes released extracellularly induce no extra injury to the granulocyte because of dilution effect; however, their release in the cytosol can cause a defect resulting in the loss of cell viability but no membrane disruption. Overall, the release of enzymes is seen as a secondary factor contributing to whole cell or membrane damage during slow freezing.

Measurement of transmitted light as an indicator of cryopreserved platelet viability

This study was designed to establish an alternative technique to the morphology scoring method described by Kunicki et al. [Transfusion 1975;15:414-421] using light transmission. A reference scale for platelet quality (expressed as a percentage of fresh cells) was established with a mixture of fresh platelets and damaged platelets frozen without cryoprotectant. The transmittance, read against autologous plasma, was compared to morphology, hypotonic stress response (HSR) and ADP-induced aggregation. The results showed that transmittance, morphology and HSR were related linearly to the percentage of fresh platelets. There was a significant correlation between relative transmittance (RT) and morphology (r = 0.932), and RT and HSR (r = 0.91), but a very poor correlation was found between transmittance and aggregation. Measurements of transmittance provided an estimation of the global aspect of a population of cryopreserved platelets in terms of shape, size and composition, and the relative transmittance of a sample to that of the fresh population could predict morphology and HSR. It is concluded that these measurements offer a valid alternative method to the subjective morphology scoring obtained with cryopreserved platelets.

Competition for nodule occupancy of introduced Bradyrhizobium japonicum strain SMGS1 in French soils already containing Bradyrhizobium japonicum strain G49

The competitiveness of Bradyrhizobium japonicum strains G49 and SMGS1 was first studied in the greenhouse in sterilized sand, with or without added soil. Strain SMGS1 was more competitive than strain G49 with soybean (Glycine max L.) cultivar Labrador but the two strains showed equivalent competitiveness with cultivar Kingsoy. When soil was added, nodule occupancy of strain G49 was only 22% with this cultivar. In field experiments, conducted over 2 years in soils already containing strain G49 (1.5 × 103 to 4.0 × 104 cells/g of soil), nodule occupancy of inoculated strain SMGS1 ranged from 20 to 90%. Nodule occupancy was 3–22% higher when inoculation was done by peat seed coating or with liquid inoculation in the row than with peat-coated clay microgranulars. Nodule occupancy was also dependent on the physiological state of the inoculated cells. When an inoculum stored at 28 °C for 1 year was used at the same viable cell rate, nodule occupancy of strain SMGS1 was 4–20% lower than with a recently made inoculum. Pot experiments with soil from field experiments carried out in the 1st year showed that the inoculated strain continued forming nodules without further inoculation, with a recovery rate equivalent to that of field experiment in the previous year.Key words: Bradyrhizobium japonicum, interstrain competition, inoculation technology, ELISA, field trials.

Sequential treatment with low dose almitrine bismesylate in hypoxaemic chronic obstructive airways disease

Daily dose schedules of 100-200 mg of almitrine bismesylate improve arterial blood gases in patients with hypoxaemic chronic obstructive airways disease (COPD) but dose related side effects are evident. In the present study, daily doses approximately half of those previously used were employed in a randomised double blind manner in 85 patients (age 35-79 years) with hypoxaemic COPD. After a one month period to check stability of arterial blood gases, patients were allocated to almitrine (A) or placebo (P) using an unequal code (60% A, 40% P). Tablets, 50-100 mg daily were stopped for one month after 3, 6 and 9 months to counteract drug accumulation. 50 patients in group A and 35 in group P were comparable on entry; mean age 65 (SD = 8) yrs., Pao2 7.8 (0.7) kPa (58.3 (5.0) mmHg), PaCO2 5.8 (0.8) kPa (43.2 (6.0) mmHg), forced expiratory volume in one second--FEV1 0.89 (0.25) l and 6 minute walking distance 296 (97) metres. The improvement in baseline PaO2 values was the same 0.8-1.3 kPa (6-9.8 mmHg) as with previous higher dose therapy. Approximately one third of patients did not respond, defined as PaO2 elevation > 0.67 kPa (5 mmHg). The sequential dosing scheme stabilised blood levels of almitrine within the therapeutic range of 280-300 ng.ml-1. After withdrawal of therapy arterial blood gases and spirometry reverted to pre-treatment levels, suggesting no permanent reversal of pathophysiology. Dose related side effects of breathlessness, indigestion and peripheral neuropathy were not observed. Nerve conduction studies revealed no difference in peripheral nerve dysfunction in hypoxaemic COPD between active and placebo therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Sequential treatment with low dose almitrine bismesylate in hypoxaemic chronic obstructive airways disease

Daily dose schedules of 100-200 mg of almitrine bismesylate improve arterial blood gases in patients with hypoxaemic chronic obstructive airways disease (COPD) but dose related side effects are evident. In the present study, daily doses approximately half of those previously used were employed in a randomised double blind manner in 85 patients (age 35-79 years) with hypoxaemic COPD. After a one month period to check stability of arterial blood gases, patients were allocated to almitrine (A) or placebo (P) using an unequal code (60% A, 40% P). Tablets, 50-100 mg daily were stopped for one month after 3, 6 and 9 months to counteract drug accumulation. 50 patients in group A and 35 in group P were comparable on entry; mean age 65 (SD = 8) yrs., Pao2 7.8 (0.7) kPa (58.3 (5.0) mmHg), PaCO2 5.8 (0.8) kPa (43.2 (6.0) mmHg), forced expiratory volume in one second--FEV1 0.89 (0.25) l and 6 minute walking distance 296 (97) metres. The improvement in baseline PaO2 values was the same 0.8-1.3 kPa (6-9.8 mmHg) as with previous higher dose therapy. Approximately one third of patients did not respond, defined as PaO2 elevation > 0.67 kPa (5 mmHg). The sequential dosing scheme stabilised blood levels of almitrine within the therapeutic range of 280-300 ng.ml-1. After withdrawal of therapy arterial blood gases and spirometry reverted to pre-treatment levels, suggesting no permanent reversal of pathophysiology. Dose related side effects of breathlessness, indigestion and peripheral neuropathy were not observed. Nerve conduction studies revealed no difference in peripheral nerve dysfunction in hypoxaemic COPD between active and placebo therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryoinjury in human granulocytes and cytoplasts

Although most isolated cells can be successfully cryopreserved, human granulocytes have little functional recovery after cryopreservation, even under optimized conditions. Cytoplasts, which are vesicles created from human granulocytes by depletion of organelles including granules and the nucleus, can carry out some of the complex functions of the parent granulocyte such as phagocytosis of bacteria, even after cryopreservation. Human granulocytes and cytoplasts were used in this comparative study of low-temperature responses to assess the relative importance of the plasma membrane and the granules in cryoinjury to human granulocytes. Boyle-van't Hoff plots of cell volume as a function of the reciprocal of osmolality showed that granulocytes and cytoplasts have similar osmometric behavior and equivalent osmotically inactive fractions. The hydraulic conductivities were also similar, indicating that the osmotic properties of the plasma membrane and cytoplasm were retained during preparation of the cytoplasts. Assessment of membrane integrity using fluorescein diacetate after graded freezing stresses showed that the low-temperature responses of cytoplasts were similar to those of human lymphocytes and hamster fibroblasts, with recoveries much higher than those of human granulocytes, particularly after post-thaw incubation at 37 degrees C. The results indicate that the plasma membrane is not the primary site of injury to granulocytes during freezing and thawing, and suggest that activation of cytoplasmic elements, such as granules, may constitute the early events in cryoinjury to human granulocytes. These studies have significance in approaches to the cryopreservation of granulocytes and other types of cells, such as platelets, with increased sensitivity to the conditions encountered during freezing and thawing.

Neuropathy in chronic obstructive pulmonary disease: a multicentre electrophysiological and clinical study

The incidence and type of neuropathy in patients with chronic obstructive pulmonary disease (COPD) were assessed. In a selected group of 89 patients, abnormal nerve conduction studies were found in 44%. Electrophysiological signs of a generalized peripheral neuropathy were found in 5-18%, depending on diagnostic criteria. Lesions which were thought to be due to compression or other forms of trauma were present in a further 24%. In the patients with peripheral neuropathy, the changes were distally predominant, affected mainly sensory fibres, and were consistent with an axonal type of neuropathy. There was a significant correlation between age and the incidence of peripheral neuropathy. Electrophysiological evidence of neuropathy was three times as common as clinical evidence. Much of the variation in the reported incidence of neuropathy in COPD is probably due to imprecise diagnostic criteria.

Neuropathy in chronic obstructive pulmonary disease: a multicentre electrophysiological and clinical study

The incidence and type of neuropathy in patients with chronic obstructive pulmonary disease (COPD) were assessed. In a selected group of 89 patients, abnormal nerve conduction studies were found in 44%. Electrophysiological signs of a generalized peripheral neuropathy were found in 5-18%, depending on diagnostic criteria. Lesions which were thought to be due to compression or other forms of trauma were present in a further 24%. In the patients with peripheral neuropathy, the changes were distally predominant, affected mainly sensory fibres, and were consistent with an axonal type of neuropathy. There was a significant correlation between age and the incidence of peripheral neuropathy. Electrophysiological evidence of neuropathy was three times as common as clinical evidence. Much of the variation in the reported incidence of neuropathy in COPD is probably due to imprecise diagnostic criteria.

Effect of a dopaminergic agonist, piribedil (Trivastal 50 mg LP), on visual and spatial integration in elderly subjects

Dopamine acts as a neuromodulator in the retina. Dopaminergic deficiency of any origin, as observed in elderly subjects, is associated with altered visual performances, and more specifically with altered perception of contrasts. The goal of this study was to compare contrast vision in elderly subjects and young subjects (first phase, n = 20), then to compare this function in elderly subjects before and after 3 months of treatment with a dopaminergic agonist, piribedil (Trivastal 50 mg LP), administered once daily (second phase, n = 20). The perception of contrast was analysed using a test measuring sensitivity to colour contrast yielding threshold values for sensitivity to contrast in eight spatial frequencies and three colours (red, green, blue) and in two directions (horizontal and vertical). The results of the first phase of the study demonstrated that elderly subjects showed a decrease in contrast perception in comparison with young subjects, primarily in the high frequency range, and over the full range of stimulation for direction and colour. In the second phase, elderly subjects, in comparison with young subjects, showed altered visual contrast, again in the high frequency range, but also in the low frequency range for horizontal simulation with red and blue. After 3 months of treatment with piribedil the mean contrast sensitivity threshold, over the entire frequency range, had significantly increased (P less than 0.05) for all stimulations, apart for red in the vertical direction. These results underline the value of treatment with a dopaminergic agonist, piribedil in visual disturbances in patients with dopaminergic deficiency (Parkinson patients or elderly subjects).

Peripheral neuropathies in patients with chronic obstructive pulmonary disease: a multicenter prevalence study

To investigate the prevalence and type of peripheral neuropathies (PNP) in patients with chronic obstructive pulmonary disease (COPD), we studied lung function and blood gases, clinical signs of PNP, and neurophysiological function in 151 patients with COPD without known risk factors for PNP. Mean (SD) age was 65 (10) years, mean arterial PO2 was 59 (9) mmHg, mean ratio of forced expiratory volume in the first second to vital capacity (FEV1.0/VC) was 42 (12%). Thirty patients (20%) had clinically detectable and 6 (4%) had subclinical PNP of mild degree. Fourteen (9%) of the patients with clinically detectable PNP had symptoms due to PNP. Prevalence of PNP increased with severity of hypoxemia (p less than 0.05) and was more pronounced in the lower than in the upper limbs. Age and the degree of hypoxemia were predictors to differentiate between COPD patients with and without PNP. Although the cause of PNP in COPD patients remains unknown, our observations suggest that chronic hypoxemia may contribute to PNP.

Evolution of peripheral nerve function in hypoxaemic COPD patients taking almitrine bismesylate: a prospective long-term study

Almitrine bismesylate has been thought to provoke peripheral neuropathies in patients with chronic obstructive pulmonary disease (COPD). However, there seems to exist alterations of peripheral nerve function in patients with COPD, who have not taken almitrine. We have therefore examined 22 patients with COPD and no other cause of peripheral neuropathy (PN), before and after 6 and 12 months of treatment with almitrine (50 mg bd). Seventy-eight similar patients, who did not take almitrine, were also studied (controls). Sixty-four per cent of controls, and 55% of almitrine patients initially had at least one neurophysiological abnormality. There was no change in the studied parameters after 6 months and one year's treatment with almitrine.

Peripheral neuropathies during hypoxaemic chronic obstructive airways disease

Peripheral nervous system alterations during chronic obstructive airways disease (COAD) with respiratory insufficiency seem more frequent than usual neurological practice would suggest. Almost a third of COAD patients have clinical evidence of peripheral neuropathy and two thirds have electrophysiological abnormalities. The presentation consists of a polyneuropathy often subclinical or with predominantly sensory signs, which has the neurophysiological and pathological features of predominantly axonal neuropathy. The presumed etiopathogenic factors are multiple: chronic hypoxia, tobacco smoke (which contains at least three neurotoxic constituents) alcoholism, malnutrition and adverse effects of certain drugs. Hypoxia probably plays the leading part, either by direct action on nerves fibres or by enhancing the effects of other neurotoxic factors or deficiencies.

Bone marrow separation, purification and cryopreservation: application for autologous bone marrow transplant (ABMT)

Autologous bone marrow transplantation is used in the treatment of patients suffering from malignant diseases. The intention of this study was to develop a technique for cryopreservation of bone marrow stem cells. A technique of purification described elsewhere (2), gave recoveries of 80% of nucleated blood cells and 87% of mononucleated blood cells after apheresis and centrifugation of buffy-coat, but when applied to bone marrow only 59% of NBC and 32% of CFUc have been harvested. We therefore modified the apheresis technique and replaced the centrifugation step by sedimentation with hydroxy-ethyl-starch. This change resulted in a small but significant increase in the yield of bone marrow cells and improved the asepsis of the procedure. From a second group of bone marrow handled with this modified protocol, final yields of 46% of NBC and 62% of MNC were obtained. After cryopreservation 87% of NBC were recovered as assessed by counting.

Comparison of the cryoprotection of red blood cells by 1,2-propanediol and glycerol

Red blood cells are cooled in buffered solutions containing 10, 15, 20, 30, or 35% (w/w) 1,2-propanediol or glycerol. Cell survival is measured after cooling to -196 degrees C at rates between 1 and 3500 degrees C/min, followed by rewarming rapidly, except in a few cases. At low cooling rates, where the injuries are due to solution effects, for the same (w/w) concentrations of 15 or 20% (w/w), 1,2-propanediol protects erythrocytes better than glycerol. Differences are still observed when the two cryoprotectants are compared on a mole-fraction basis. At high cooling rates the survival passes through a minimum and then increases again. For the same concentrations, the minimum occurs at much lower cooling rates with 1,2-propanediol than with glycerol, in agreement with the better glass-forming tendency of 1,2-propanediol solutions. These cooling rates almost coincide with those at which the quantity of ice crystallized begins to decrease in the corresponding solutions. Thus, survival seems to be closely related to the glass-forming tendency at the survival minimum, and at higher cooling rates. After the fastest cooling rates, the warming rates necessary to avoid damage on warming are much smaller than those necessary to avoid devitrification. Therefore, in the present experiments the survivals are not related to the stability of the wholly amorphous state. However, injury follows the presumed transition from cubic to hexagonal ice, in erythrocytes as well as in other kinds of cells.

Comparison of apheresis and other methods for separation and purification of hemopoietic stem cells: initial experience with a blood buffy coat model for the use of autologous bone marrow transplantation

With an increasing number of bone marrow transplantations (BMT) being contemplated in leukemia and cancer patients, it is prudent for blood banks to develop a suitable program within their resources for harvesting, purifying and freezing bone marrow stem cells. In order to do this, initially a prototype has been developed involving buffy coat model (BC) using normal donor blood. Centrifugation, sedimentation and machine apheresis methods were separately evaluated leading to a combined and sequential handling procedure. Blood was passed through a cell separator resulting collection of BC with 90% reduction of the volume showing 80% recovery of total leucocytes and 87% yield of mononuclear cells. Following centrifugation the cells with DMSO were frozen in a controlled freezing system and stored in liquid nitrogen. After thawing 94% cells were recovered with 93% viability. The initial experience gained in the model system could be incorporated in autologous BMT program in patients but requires modifications for improved results; the latter will be described separately.

Autologous cryopreserved platelets and prophylaxis of bleeding in autologous bone marrow transplantation

Autologous platelets were harvested and cryopreserved in eight consecutive patients elected for ablative chemotherapy and autologous bone marrow transplantation (ABMT) for solid malignancy. There was a 19% loss in platelet count after the freeze thaw and wash procedure; with an in vitro functional loss of 40-60%. No correlation could be found for individual platelet transfusions between in vitro functional tests and in vivo recovery. Six consecutive patients received a total of 16 autologous platelet transfusions in the aplastic phase of ABMT. No bleeding was observed during the study period and there was no CMV infection in the recipients. While improvement in freezing and subsequent handling is desirable, autologous cryopreserved platelets can safely be used for the prophylaxis of bleeding during aplasia in patients treated with ABMT.

[Hypoxemia and aging (author's transl)]

Hypoxemia during rest reveals the aging of the respiratory tract. The evolution curve of the PaO2 related to age is parallel to that of static elastic recoil pressure. This hypoxemia is moderate and without any serious functional consequences in a healthy subject. Abnormalities of the ventilation-perfusion ratio are the main causes. The increase of the anatomical dead space and the increase of the right-left shunt only play a moderate part. On the other hand the increase of closing volume seems the major factor. Thus the ventilation distribution becomes dependent on the amplitude of the tidal volume. The response of the aged subject to hypoxia is lessened for mechanical and neurological reasons explaining why a respiratory distress can appear rapidely and sometimes unexpectedly.

[New therapeutic indications for a dopamine antagonist, Piribedyl]

Evidence has been found for the view that piribedil stimulates peripheral and central dopamine receptors. Piribedil stimulates the nigro-striatal pathway and has been shown to be an effective antiparkinsonian agent. The stimulation of dopamine receptors in the meso-limbic and/or meso-cortical pathways lead to propose its use in the treatment of affective disorders (maia and depression). Piribedil stimulates dopamine receptors located in the tubero-infundibular pathway and reduces the secretion of prolactine, producing ablactation ; it increases the secretion of STH. Recent studies suggest that the peripheral effects of piribedil, mainly the increases in femoral and cerebral blood flows are also due to stimulation of peripheral dopamine receptors.