In vitro and in vivo evaluation of the haematopoietic potential of skeletal muscle in a non-human primate model.

This study was aimed at evaluating the in vitro and in vivo haematopoietic potential in macaque skeletal muscle cells. Biopsy samples showed the presence of CD34(+) (7.6%), CD90(+) (8.4%), CD117(+), CD31(+), side population (SP) cells (7-10%) and a low number of CD45(+) cells. In clonogenic and long-term culture-initiating cell assays, no haematopoietic potential could be detected in either total mononuclear cells or SP cells. Regarding in vivo studies, two animals were transplanted with unfractionated fresh muscle cells after lethal irradiation. Both animals died early after transplant without any evidence of haematopoietic reconstitution. In two other monkeys, harvested muscle cells were frozen and secondarily marked using a green fluorescent protein (GFP)-lentiviral vector. After sublethal irradiation, both animals were transplanted with GFP-expressing muscle cells followed by a bone marrow rescue. Both animals had haematopoietic reconstitution at days 22 and 25, but no GFP-expressing haematopoietic cells could be detected by flow cytometry, either in the blood or in clonogenic cells from marrow aspirates. Using PCR assays, GFP(+) cells were detected in a single marrow sample of one animal at 41 days after transplantation. These results strongly suggest that as opposed to murine muscle, the non-human primate skeletal muscle does not harbour cells with a straightforward haematopoietic potential.

[Changing medical practices and nosocomial infection rates in French maternity units from 1997 to 2000]. / Surveillance des infections nosocomiales dans les maternités du sud-est de la France entre 1997 et 2000.

OBJECTIVES: In this study we describe the changes in medical practices and nosocomial infection rates in obstetrics observed through a surveillance network in the South East of France. MATERIAL AND METHOD: The maternity units which belong to this network participated in voluntary surveillance using the network's methodology. The criteria for the diagnosis of nosocomial infections were in accordance with the methods described by the Centers for Disease Control and Prevention. RESULTS: 101240 pregnancies including 18503 caesareans (18.3%) were included in the network from 1997 to 2000. During the study period, nosocomial infection rates following caesarean section and vaginal delivery decreased respectively from 7.8% to 4.3% (p < 0.001) and from 2.2% to 0.9% (p < 0.001). This evolution was compared with the evolution of collected risk factors. CONCLUSION: In spite of the methodology limits, general value of surveillance and infection control programs in maternity units has been confirmed by the results of this surveillance network. During the study period, both obstetrics-related risk factors for nosocomial infection and observed hospital-acquired infection rates were dramatically reduced, what prove an improvement of quality of care in maternity units.

Cortisol influences the host-parasite interaction between the rainbow trout (Oncorhynchus mykiss) and the crustacean ectoparasite Argulus japonicus.

The host-parasite interaction between the rainbow trout Oncorhynchus mykiss and the fish louse Argulus japonicus was investigated by administering low levels of dietary cortisol before infecting the fish with low numbers of the parasite. After 24 h, the dietary cortisol treatment elevated blood cortisol and glucose levels and stimulated the synthesis of secretory granules in the upper layer of skin cells. Infection with 6 lice per fish caused skin infiltration by lymphocytes, also in areas without parasites. The lymphocyte numbers in the blood at 48 h post-parasite infection were reduced. Other changes, typical for exposure to many stressors and mediated by cortisol, were also found in the epidermis of parasitized fish, although neither plasma cortisol nor glucose levels were noticeably affected. Glucocorticoid receptors were localized immunohistochemically and found in the upper epidermal layer of pavement and filament cells, and in the leucocytes migrating in these layers. Cortisol-fed fish had reduced numbers of parasites and the changes in the host skin are likely involved in this reduction. Thus a mild cortisol stress response might be adaptive in rejecting these parasites. Further, the data suggest that this effect of cortisol is mediated by the glucocorticoid receptor in the skin epidermis, as these are located directly at the site of parasite attachment and feeding in the upper skin cells that produce more secretory granules in response to cortisol feeding.

Identification of respiratory and ion-transporting epithelia in the phyllosoma larvae of the slipper lobster Scyllarus arctus.

Phyllosoma larvae of the Palinura lack a branchial cavity and gills. In the phyllosoma, gas and ion exchanges that occur at the level of the gill in the adult must occur in other parts of the body or through the entire body. The objective of this study was to localize epithelia bordering the body of the phyllosoma larvae that had features comparable to those of the gill epithelia of adult decapods. The first phyllosoma instar of the small Mediterranean slipper lobster Scyllarus arctus was studied. First, we used a silver nitrate staining method to identify parts of the body with high ionic permeability. Confocal laser scanning microscopy with a fluorescent vital stain for mitochondria, dimethylaminostyrylmethylpyridiniumiodine (DASPMI), was then used to localize cells with a high density of mitochondria. Next, an ultrastructural study of selected epithelia was carried out. A thick (5 microns) mitochondria-rich epithelium covers the ventral side of the cephalic shield; its cells are characterized by the presence of well-developed apical infoldings adjacent to the cuticle. This part of the body has a high ionic permeability as indicated by a positive silver nitrate staining. The ventral mitochondria-rich epithelium might be involved in active ion transport. The rest of the body, particularly the dorsal side of the shield and the appendages, shows a lower ionic permeability (no positive silver nitrate staining) and is limited by a thin (1 micron) epithelium with low numbers of mitochondria. This epithelium exhibits features of a typical respiratory epithelium.

Ecophysiological adaptation to salinity throughout a life cycle: a review in homarid lobsters.

Adaptations to salinity are reviewed throughout development in both species of the genus Homarus. Some populations of homarid lobsters are known to inhabit coastal and estuarine areas where salinity fluctuates. Salinity tolerance varies during development, with 50 % lethal salinities (LS(50)) ranging from approximately 15-17 in larvae to approximately 12 in postlarvae and 10 in adults. Larval and adult lobsters can avoid low-salinity areas using behavioural strategies. When exposed to low salinity, the capacity to osmoregulate varies with development. Embryos are osmoconformers and are osmotically protected by the egg membranes. Larvae are also osmoconformers, and the pattern of osmoregulation changes at metamorphosis to hyper-regulation, which is retained throughout the later stages up to the adult stage. Exposure to low salinity increases the activity of Na(+)/K(+)-ATPase in postlarvae and later stages. The level of osmoregulation evaluated through the osmoregulatory capacity (the difference between haemolymph and medium osmolalities) is negatively affected by low temperature (2 degrees C). The variations in haemolymph osmolality resulting from osmoconforming or partial osmoregulation are compensated by intracellular iso-osmotic regulation. Neuroendocrine control of osmoregulation appears in postlarvae and seems to involve the crustacean hyperglycaemic hormone. In adult lobsters, the gills appear to have a respiratory function only, and extracellular osmoregulation is effected by the epipodites, with the addition of the branchiostegites at low salinity. These organs are present at hatching. Transmission electron microscopy and immunolocalization of Na(+)/K(+)-ATPase reveal that the epipodites become functional in larvae and that the branchiostegites become functional in postlarvae. An integrated series of events links the appearance of osmoregulatory tissues, the increase in Na(+)/K(+)-ATPase activity, the occurrence in postlarvae of hyper-regulation at low salinity and the increase in salinity tolerance. Further ecological and physiological studies are proposed for a better understanding of the adaptive significance of the ontogeny of osmoregulation in lobsters.

The use of steroids in the management of inoperable intestinal obstruction in terminal cancer patients: do they remove the obstruction?

This multicentre, randomized double-blind study was undertaken to assess the efficacy of corticosteroids as a palliative treatment of intestinal obstruction due to advanced and incurable cancer. Thirty-one French palliative care units agreed to participate in the study and 12 actually recruited at least one patient. To be included, patients had to have an advanced cancer with a surgically inoperable bowel obstruction and to have received no specific anticancer therapy within the preceding 28 days. They had to fulfil at least three of the following criteria: vomiting at least twice a day; colicky abdominal pain; no flatus for 12 h or more; no stool for at least 4 days, faecal impaction being excluded; intestinal distension; air-fluid levels or absence of gas in the colon on an abdominal radiograph. Patients were randomized in three groups to receive either a placebo for 3 days (group A), or methylprednisolone 240 mg daily for 3 days (group B) or methylprednisolone 40 mg daily for 3 days (group C). Symptoms were assessed daily but success or failure of the treatment was assessed on day 4, according to the disappearance or persistence of symptoms. Fifty-eight patients were randomized, of whom 52 were able to be evaluated. Details of symptoms and associated treatments are described below. Of 40 patients without a nasogastric tube, symptoms were relieved in 68% of cases versus 33% among placebo-treated patients (P = 0.047). In 12 patients who had a nasogastric tube already in place, the results are less significant (60% versus 33% with P = 0.080). Because of the small sample size, no conclusions can be reached about the relative efficacy of low versus high-dose treatment regimes.

[Indicators of quality for hospital antisepsis]. / Indicateurs de qualité pour l'antisepsie à l'hôpital.

In any health care institution, the most important quality indicator for antisepsis is the existence of systems of reference of use, secondly the knowledge of those systems and then the compliance by the different classes of professionals. These refrentials must be regularly evaluated and updated according to general consensus.

Na(+) and Ca(2+) pumps in the gills, epipodites and branchiostegites of the european lobster Homarus gammarus: effects of dilute sea water.

Crude homogenates and plasma-membrane-enriched fractions were prepared from the epithelium of the gills, epipodites and branchiostegites of intermoult European lobsters Homarus gammarus, and Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Na(+)/Ca(2+) exchange activities were quantified in these tissues. Lobsters were kept in sea water (salinity 35 ) or were adapted to dilute sea water (22.1 ). The lobster hyperregulates haemolymph osmolarity and Ca(2+) levels in both media. Homogenates of the podobranchs, arthrobranchs and pleurobranchs had comparable Na(+)/K(+)-ATPase specific activities, and mean activities increased significantly for all three types of gills when the animals were kept in dilute sea water. In the epipodites and branchiostegites, Na(+)/K(+)-ATPase specific activities exceeded those in the gills, and exposure to dilute sea water greatly enhanced these activities. In sea water, 80 % of the total Na(+)/K(+)-ATPase activity is associated with the gills and epipodites (each tissue containing 40 %) and 20 % with the branchiostegites; in dilute sea water, the gills contained approximately 25 %, the epipodites 40 % and the branchiostegites approximately 35 % of the total activity, indicating the relative importance of the epipodites and branchiostegites for ionic hyperregulation in dilute media. In plasma membrane vesicles isolated from the gills, epipodites and branchiostegites, Ca(2+) transport driven by ATP and by a Na(+ )gradient was demonstrated. Exposure to dilute sea water enhanced Na(+)/Ca(2+ )exchange and Ca(2+)-ATPase activities in the epipodites and branchiostegites; in the gills, however, Ca(2+) transport activities decreased. The role of these tissues and enzymes in Na(+) and Ca(2+) handling by the lobster is discussed.

Ontogeny of intracellular isosmotic regulation in the european lobster Homarus gammarus (L.).

Intracellular free amino acids were measured in the abdominal muscle of the three larval instars, postlarvae, and juveniles of the lobster Homarus gammarus, acclimated to seawater (35 per thousand) and to a dilute medium (22 per thousand), to study intracellular isosmotic regulation throughout the development of this species. Transfer to low salinity was followed by a highly significant drop of free amino acids level in all developmental stages. The main regulated amino acids were glycine, proline, and alanine. The level of regulation of total free amino acids changed at metamorphosis: the decrease in total free amino acids at low salinity was 46% in the three larval instars, but it was only 29% in postlarvae and 20% in juveniles. These results suggest that free amino acids, mainly glycine, proline, and alanine, are involved in intracellular isosmotic regulation in the lobster, with different levels of involvement in pre- and postmetamorphic stages. The ontogenetic changes in intracellular isosmotic regulation are discussed in relation to the changes in extracellular regulation (osmoregulation) in the lobster.

Confocal laser scanning and electron microscopical studies on osmoregulatory epithelia in the branchial cavity of the lobster homarus gammarus

The adult lobster Homarus gammarus is a weak hyper-regulator at low salinity. The objective of this study was to locate the ion-transporting tissues in the branchial chamber of this species, using electron microscopy and confocal laser scanning microscopy with a fluorescent vital stain for mitochondria, DASPMI, which is widely used to locate mitochondria-rich cells in ion-transporting epithelia of fish. A thick mitochondria-rich epithelium is present on the inner side of the branchiostegite and over the entire surface of the epipodites. Ultrastructural observations confirm that this tissue has features typical of an ion-transporting epithelium. When the lobster is transferred to low salinity, these epithelia undergo marked ultrastructural changes, such as an increase in thickness related to the development of basolateral infoldings, the appearance of numerous vesicles and an increase in height of the apical microvilli. In the gills, the branchial filaments are lined by a thin and poorly differentiated epithelium, containing numerous mitochondria; no significant ultrastructural changes were observed in the gills of animals acclimated to low salinity. In summary, in H. gammarus, no evidence of osmoregulatory structures was found in the gills. Differentiated ion-transporting epithelia are present in the branchial cavity, on the inner side of the branchiostegite and on the epipodites; these organs are probably involved in osmoregulation.