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Les enjeux de l’ethique de la recherche occupent une place de plus en plus importante dans la gestion de la recherche tant sur le plan international qu’a l’echelle nationale. Au Canada et au Quebec, ces preoccupations ont donne lieu a plusieurs documents recents provenant d’instances regulatrices gouvernementales et paragouvernementales. Celles-ci privilegient des approches diverses : agrement fonde sur la surveillance des structures institutionnelles de l’ethique de la recherche, encadrement legislatif de l’ethique ou enonce de politique fonde sur des principes d’autoregulation des chercheurs, tout en maintenant un cadre ethique base sur la deliberation des comites d’ethique de la recherche. Ces trois principales approches sont presentees apres les avoir situees dans les courants ethiques contemporains.

Resume La litterature financiere permet de penser que l'existence de certaines anomalies empiriques pourrait etre attribuable a la nature non diversifiable du facteur risque d'estimation. L'effet cours-benefices, l'effet taille, l'effet des firmes negligees et l'effet de janvier seraient en particulier associables a un effet d'information; ces variables de nature informationnelle agiraient comme variables substituts pour le degre de risque d'estimation. Or, le risque d'estimation fait implicitement reference aux jugements probabilistes des investisseurs en situation d'ambiguite. Cet essai presente les resultats d'une experience mettant en evidence l'existence de biais cognitifs dans le traitement par les investisseurs des variables informationnelles directement liees au risque d'estimation. Ces biais systematiques dans le traitement de l'information par l'investisseur ne constitueraient-ils pas une composante du risque d'estimation ? Abstract Financial literature suggests that observed anomalies could be attributable to the non-diversifiable character of the risk of estimation. The size effect, the January effect, the price/earnings effect, and the effect of neglected firms could all be associated with an information effect, and could therefore act as surrogates for the risk of estimation. To be sure, the risk of estimation implicitly assumes that investors apply a probabilistic judgment in the face of ambiguity. This study presents the results of an experiment that proves the existence of cognitive biasses when informational variables are directly related to the risk of estimation. Are these systematic biasses in the analysis of information by investors the reflection of one component of the risk of estimation ?

Les questions à portée éthique qui se manifestent en recherche traversent la bioéthique de ses origines à ses développements les plus récents. Formulées initialement surtout de l'intérieur des frontières américaines, berceau de ce mouvement social, elles trouvent aujourd'hui écho dans plusieurs pays du monde, même en dehors du contexte occidental. Leur présence se fait particulièrement vive là où l'expérimentation porte sur des êtres humains. Depuis les années 1960, la bioéthique a évolué et s'est « spécialisée » en différents secteurs. Qu'est-il advenu de son volet « éthique de la recherche » entre les jours de ses premiers balbutiements et ceux qui ont vu la publication de l'Enoncé de politique des trois conseils? Dans quelle mesure les espoirs qui habitaient ses fondateurs se sont-ils réalisés? Ces deux questions feront l'objet de la présente réflexion., Questions of ethical implications in research mark the field of bioethics from its origins until its most recent developments. These questions were initially formulated within the U. S. A., the cradle of this social movement. However, since then they have gained ground in other countries, even beyond the western world. Bioethics is especially present in places where experimentation is carried out on human beings. Since the 1960s this discipline has evolved and "specialised" in different sectors. What has become of the "ethical side of the research" from the first emergence of bioethics until the publication of the "Énoncé de politique des trois conseils" ? To which extent have the hopes of its founders been realised ? These are the two questions which the present reflection deals with.

Cadmium (Cd) uptake was studied under inorganic exposure conditions in normal human intestinal crypt cells HIEC. The uptake time course of 0.3 microM Cd in a serum-free chloride medium was analyzed according to a first order equation with rapid initial (U0) and maximal (Umax) accumulation values of 14.1+/-1.4pmol/mgprotein and 41.4+/-2.0 pmol/mgprotein, respectively. The presence of a 300-fold excess of unlabeled Cd dramatically decreased tracer uptake, showing the involvement of specific mechanism(s) of transport. Our speciation studies revealed the preferential uptake of the free ion Cd2+, but also suggested that CdCln(2-n) species may contribute to Cd accumulation. Specific mechanisms of transport of very high and similar affinity (Km approximately 5 microM) have been characterized under both chloride and nitrate exposure conditions, but a two-fold higher capacity (Vmax) was estimated in the nitrate medium used to increase [Cd2+] over chlorocomplex formation. A clear inhibition of 109Cd uptake was observed at external acidic pH under both exposure media. An La-inhibitible 46% increase in 109Cd uptake was obtained in nominally Ca-free nitrate medium, whereas Zn provided additional inhibition. These results show different kinetic parameters for Cd uptake as a function of inorganic metal speciation. Cd2+ uptake would not involve the H+-coupled symport NRAMP2 but would be related instead to the Ca and/or Zn pathways. Because proliferative crypt cells play a critical role in the renewal process of the entire intestinal epithelium, studies on the impact of Cd on HIEC cell functions clearly deserve further investigation.

Lieu de manifestation de la tension entre deux pôles de l'activité de recherche, celui du développement des connaissances et celui de la protection des sujets humains, le suivi éthique des projets de recherche est marqué par des problèmes conceptuels et de mise en application. Or, ces problèmes sont amplifiés par le développement de nouvelles avenues de recherche comme celle de la thérapie génique. Dans ce contexte, le rapport annuel ou le rapport d'étape, exigé par le comité d'éthique de la recherche, constituent un exemple d'articulation, avec ses forces et ses faiblesses, entre une visée éthique et son application., Theater for the tension between two main aspects of research, the development of knowledge and the protection of the human subjects, the continuing ethics review of research projects must cope with a conceptual problem on the one hand and an implementation one on the other. Both problems are magnified by the development of new avenues of research, such as in genetic therapy. In this context, the Research Ethics Committee's requirement for an annual report or progress reports constitutes an example of interaction, with all its strengths and weaknesses, between an ethical goal at its applications.

L’ethique en recherche au Benin s’est developpee au cours de la derniere decennie entre autres par l’entremise d’un partenariat avec le Quebec et ce, en puisant dans le cadre canadien en ethique de la recherche, l’EPTC2. En s’appuyant sur un triptyque de valeurs composes du respect de la dignite humaine, du respect de la diversite culturelle et de la solidarite, l’ethique de la recherche s’y est structuree comme un des fruits du partenariat. Des comites d’ethique de la recherche locaux, des chercheurs et des etudiants ont acquis les outils necessaires pour resoudre la plupart des dilemmes ethiques qui se presenteront a l’avenir dans le cadre de la recherche impliquant des etres humains. Retrospectivement, cette initiative a ete le lieu de resurgence de la bioethique telle que definie par Van Rensselaer Potter mais appliquee a un contexte resolument francophone.

The effects of two widely used paramagnetic shift reagents for cationic NMR, dysprosium tripolyphosphate [Dy(PPP)2(7-)] and dysprosium triethylenetetramine hexaacetate [Dy(TTHA)3-], on the cell structure of dog and human erythrocytes, dog kidney cortical tubules and rat hepatocytes were investigated. The effect of shift reagents on cell integrity was monitored by measuring the hematocrit values for erythrocytes, by measuring the lactate dehydrogenase (LDH) release and by electron microscopy for cortical tubules and hepatocytes. The quantitation of the dyprosium penetration inside cells was accomplished by atomic absorption, atomic emission and neutron activation. More severe effects were observed with Dy(PPP)2(7-) than with Dy(TTHA)3-, and were dependent on the divalent cation concentration and on the shift reagent concentration. Very serious cell damage was observed after 60 min incubation in the presence of 10 mumol Dy(PPP)2(7-)/mL suspension at low or high divalent cation concentration. The situation was improved at 5 mumol Dy(PPP)2(7-)/mL suspension especially at high divalent cation concentration (2.5 mM). Incubation with Dy3+, PPP5- or Dy(TTHA)3- caused little or no structural effects but dysprosium was found to penetrate slowly inside tubules with Dy(TTHA)3-. Both Dy3+ and Dy(PPP)2(7-) penetrated rapidly inside cells. Dysprosium was found to bind to the isolated cytosol but not to isolated membranes, eliminating the possibility of extracellular membrane binding.

Mycobacterium ulcerans (M. ulcerans) causes Buruli ulcer, a very debilitating disease that affects the skin and other tissues. The disease occurs mainly in children in sub-Sahara Africa. While contracture, fibrosis and functional limitation of range of motion are frequent complications of Buruli ulcer, no fundamental or clinical studies have investigated the impact of M. ulcerans infections on skeletal muscle. In the present study, we subcutaneously infected mice in the proximity of the right biceps muscle to evaluate the histological, biochemical and functional impact of M. ulcerans on skeletal muscles. The concentration of mast cells decreased but the number of neutrophils and macrophages increased steadily in proximate-infected biceps muscles. Pro- and anti-inflammatory cytokines as well as fibrogenic growth factor mRNA also increased. Significantly more membrane damage and fibrosis occurred in proximate-infected biceps muscles than in control and sham muscles. Passive biomechanical testing also revealed that the presence of M. ulcerans increased muscle stiffness. These findings show for the first time that M. ulcerans can induce local and chronic inflammatory responses in skeletal muscles that are associated with muscle fiber damage and fibrosis.

The polymorphism of the endoplasmic reticulum (ER) in epithelial cells with different transport functions such as the enterocyte suggests that the ER may be involved in some way in molecular transport. To further access this possibility, we examined the ER from the intestine of winter flounder, Pseudopleuronectes americanus, a species which undergoes an annual fast of approximately 6 months' duration, a time during which previous work indicates nutrient carrier number does not change. Fish from June (feeding) and January (8-10 weeks fasted) were sampled. Tissues from the pyloric caeca, foregut, midgut, and hindgut were prepared for electron microscopy using two techniques of staining. Cell height was unaltered in any section, although microvillar length shortened variably. Cellular organization, including position of nuclei, number and distribution of mitochondria, and presence of basolateral membranes, did not change. The ER appeared equally abundant in June and January. However, use of the osmium impregnation technique, which is specific for ER cisternal contents, revealed a change in the impregnation of ER, from a heavily impregnated network in summer to little or no impregnation in winter. These results suggest that a shift in function of the ER had occurred when nutrient transport ceased, and supports a role of the ER in nutrient transport.

Renal Fanconi syndrome is a tubular dysfunction increasing the urinary excretion of glucose, amino acids, phosphate and bicarbonate and inducing rickets in children and osteomalacia in adults. Keywords: aminoaciduria; cadmium; cystinosis; glucosuria; maleate; megalin; phosphaturia; renal tubular acidosis; rickets; osteomalacia

Avec l’entrée en vigueur de l’Énoncé de politique des trois conseils, la surveillance éthique continue fait maintenant partie intégrante du processus d’évaluation éthique sur la scène universitaire canadienne. Pourtant, malgré l’acceptation de ce concept, les chercheurs et les institutions se questionnent sur sa portée et sa mise en application. Dans cette perspective, cet article porte un regard sur les racines et les variantes du concept, les efforts de rationalisation dont il a fait l’objet en contexte américain d’où il a émergé et sur le contexte de son entrée sur la scène canadienne. With the application of the Tri-Council Policy Statement. Ethical Conducts for Research Involving Humans, the continuing ethics review of research projects involving humans is now part of the ethical evaluation process in all concerned Canadian universities. However, in spite of the acceptance of this concept, researchers and institutions are puzzled by its significance and its application. In this context, this paper brings a light on the roots and various forms of the concept, on the attempts made to rationalize these forms in the United States and on the overall picture of its introduction on the Canadian scene.

The corporate loan decision making process is a central concern in financial literature and amongst practitioners. The process, though entails many difficulties. There is, for example, no consensus in the literature on the choice or on the relative weight of the potentially relevant aspects (the macro-economic, financial, and management assessment aspects, and the aspect of the value of loan collateral) that one should take into account in a decision on a loan. The literature is also in disagreement as to how these aspects can be combined (aggregation) in order to generate a global judgement. Moreover, the information necessary in seizing these aspects most often comes in different scale units and results from evaluations which are subjective or more or less exact. Most models that are developed for loan decision, limit themselves to quantitative financial variables; they also tend to evacuate or ignore the role of the loan officer in the process, and this even if the decision maker’s judgement and appreciation of qualitative aspects is recognized as a key factor in the process. This paper shows how a multicriterion methodology based on outranking relationships can assist the loan officer in his or her attempt to surmount the difficulties involved in loan request evaluation. The method proposed is tested over a sample that contains about three hundreds of loan requests addressed to a large Canadian financial institution

Previous studies have shown that histochemical modifications of the endoplasmic reticulum in epithelial cells might be related to their transport function. We have examined the effect of sodium maleate, which produces generalized transport derangement reminiscent of Fanconi syndrome, on the organization, morphology and enzyme activities of endoplasmic reticulum in rat kidney cells. The osmium impregnation technique has revealed that apical vacuoles increase in volume and in number in most proximal tubule cells, and contain osmium deposits. Osmium impregnation of the endoplasmic reticulum is much reduced. In vitro studies, performed with isolated microsomes, show NADPH cytochrome c reductase activity in both normal and maleate-treated rats. As revealed by vanadate, Ca+-ATPase activity in isolated microsomes is unnaffected by maleate but the vanadate-insensitive or passive component of calcium uptake increases particularly later in the response. Therefore, the remaining calcium uptake in the presence of vanadate is indeed passive; in vivo maleate administration also appears to increase the passive entry of calcium into the microsomal compartment. The morphological and histochemical alterations of the endoplasmic reticulum cisternae occur rapidly and with a similar time course to the transport defects, suggesting that this organelle plays a role in transcellular transport. Maleate may directly affect the endoplasmic reticulum membranes whereby passive permeability to calcium is increased. The endocytotic apparatus and possibly exocytosis phenomena are modified by maleate as shown by the increased vacuolization and the presence of black osmium deposits in vacuoles.

We describe a simple new technique based on the affinity of imidazole and osmium tetroxide for unsaturated lipids. Organs (e.g., kidney, liver, intestine) were perfused in vivo with a glutaraldehyde solution. Tissue fragments were then immersed in a solution containing imidazole and OsO4 and are further stained with a double lead and copper citrate solution. Ultra-thin (0.06 microns) or thick (0.1-0.3 microns) sections were observed with transmission electron microscopy (80-100 kV). The method presented permits excellent visualization of cell membranes (e.g., endoplasmic reticulum, endocytotic apparatus) because it favors good resin penetration and the alkaline pH preserves cell volume. A better stereomicroscopic analysis of the relationship between cell organelles can be carried out with thick sections. The imidazole/osmium can be used routinely because the technical steps are easy and simple to follow. Furthermore, it can complement other cytochemical methods.

The endoplasmic reticulum is generally absent from schematic representations of transport phenomena, although it shows a well-organized network in most transport epithelial cells. In order to examine the correlation between this organelle and cellular activity, bladders of Bufo marinus were studied under different experimental conditions and fixed by immersion in glutaraldehyde, followed by OsO4 impregnation for 3 days. Normal granular and mitochondria-rich cells showed a rich cytoplasmic network of canaliculi, well-impregnated by osmium deposits. Following a 2 to 15-min stimulation (serosal bath) with arginine vasopressin, the V2 receptor agonist dD-arginine-vasopressin or cyclic AMP (cAMP), the staining of endoplasmic reticulum in granular cells disappeared. After washing out of the hormone or the agonist, impregnation of the endoplasmic reticulum could be observed once again. Arginine vasopressin did not modify the impregnation of endoplasmic reticulum of either mitochondria-rich or basal cells. Our data indicate a correlation between the reactivity of endoplasmic reticulum to osmium, and a cAMP-dependent effect of arginine vasopressin through its V2 receptors. Incubation of toad bladders carried out with agents interfering with cellular calcium (calcium ionophores, high or low bath calcium) or with calcium release from the endoplasmic reticulum (TMB-8, thapsigargin) suggested that an early step in the cAMP-dependent effect of arginine vasopressin must involve the release of intracellular calcium from the endoplasmic reticulum. However, calcium ATPases in this organelle do not seem to participate in the hormonal effect. The reversible loss of osmium impregnation induced by arginine vasopressin may represent protein changes in the endoplasmic reticulum accompanying a cAMP-dependent calcium release, from the organelle.

The spatial organization of the endoplasmic reticulum has been studied in two renal cell lines, MDCK and LLC-PK1, which originate from the distal and proximal portions of the mammalian nephron, respectively, and which form a polarized epithelium when they reach confluence in tissue culture. The two renal cell lines, grown to confluence on either solid or permeable supports, were investigated by fluorescence microscopy, confocal microscopy, and transmission electron microscopy. Fluorescence labeling of the endoplasmic reticulum was achieved using the cationic fluorescent dye DIOC6 (3). In order to differentiate fluorescent labeling of the endoplasmic reticulum from that of the mitochondria, cells were also labeled with rhodamine 123. For electron microscopy, the spatial organization of the endoplasmic reticulum was examined in thick sections using the long-duration osmium impregnation technique or the ferrocyanide/osmium technique. In both cell lines, the endoplasmic reticulum formed an abundant tubular network of canaliculi that frequently abutted the basolateral domain of the plasma membrane and occasionally the apical membrane. Elements of the endoplasmic reticulum were also found in close proximity to mitochondria that, as in the nephron, formed branched structures. Canaliculi appeared circular or flattened and had an inner diameter of 10–70 nm for MDCK cells and 20–90 nm for LLC-PK1 cells. Such a three-dimensional organization might facilitate the translocation of defined lipid species between the endoplasmic reticulum and the plasma membrane, and between the endoplasmic reticulum and mitochondria.

The aim of this study was to define further the interaction between osmium and organelle content in cells prefixed with glutaraldehyde. We have studied the reaction of osmium with divalent or trivalent cations (calcium, barium, zinc, aluminum, and iron) and various amino acids in the same conditions prevalent in histological techniques, in particular with Thiery's technique of metal impregnation. Experiments were carried out in vitro in test tubes, on cellulose acetate discs, or with an immunodiffusion apparatus. Some experiments were also carried out with tissue extracts (kidney and intestine). Our studies suggest that calcium is in general essential for the formation of osmium black, but also that lysine is reactive even in the absence of calcium and that a few amino acids--such as tryptophan, ornithine, cysteine, and aspartic acid--are only slightly reactive in the absence of calcium. Other amino acids do not seem to participate in the endoplasmic reticulum osmium impregnation even in the presence of calcium ions. Our studies also suggest that osmium reactivity reflects calcium binding sites and not only calcium content.

We describe a novel technique for the histochemical and cytochemical demonstration of glucose-6-phosphatase activity. In this method, lead is replaced by cobalt. After activity of glucose-6-phosphatase, cobalt phosphate Co3(PO4)2 is formed, and in the presence of ammonium sulfide (NH4)2S, the precipitate is transformed into a sulfide that fixes osmium and provides good electron density. Glucose-6-phosphatase activity was determined mostly in rat kidney cells, but controls were also performed in liver cells. A strong reaction was seen in proximal tubule cells, but the reaction was weak in distal convoluted tubule cells. This technique showed the same endoplasmic reticulum (ER) organization in proximal and distal nephron as that seen with the osmium impregnation technique. In collecting tubules, intercalated cells had irregular reactivity, while principal cells had none. Our results indicate that the cobalt technique is valid, reliable, and sensitive enough to detect low glucose-6-phosphatase activity. Moreover, the technique can be used with 1-mm-thick specimens and obviates the need for use of frozen tissue sections.

We have determined the kinetics of endoplasmic reticulum (ER) reconstitution following insertion of rat-liver smooth microsomes (SM) into Xenopus oocyte cytoplasm using electron microscopy as well as cytochemistry and thick-section 3-dimensional reconstruction. Oocytes were fixed 0, 10, 20, 40, 80, and 120 min after microinjection with SM and processed for thin- and thick-section electron microscopy. At 0 min postinjection, rat liver SM were observed as small vesicles and were loosely dispersed amongst oocyte organelles. At 10 min, tubules were discerned among many elongate vesicles; and these structures comprised large cytoplasmic regions delimited by mitochondria and yolk platelets. By 20 min, segregation of transplanted organelles yielded yolk-platelet-free regions composed of few vesicles but increasingly numerous, long and anastomosing tubules. By 40 min, a network with numerous tubular branches and fenestrations was observed among the few remaining vesicles. By 80 min, transformation of rat liver SM into a complex network of branching and anastomosing tubules was complete. Three-dimensional reconstruction revealed the network to be composed of interconnecting elements consisting of anastomosing tubules. The reconstituted network of anastomosing tubules in Xenopus oocytes was compared to the network of anastomosing tubules in rat liver hepatocytes and was found to be essentially identical. Network formation occurred in oocytes pretreated with either vinblastine (40 microM) or nocodazole (0.166 microM), and network organization was maintained in oocytes treated with the same drugs after microinjection and reconstitution. We conclude that SM retain sufficient molecular information for rapid self-assembly into structures resembling those in the cells from which they were derived. Both the assembly and maintenance of ER structure in oocyte cytoplasm are microtubule-independent. The formation of such structures following microinjection of SM into living cells provides a unique assay for this type of membrane subfraction.

La recherche avec des sujets humains souleve une aporie : le bien commun espere du developpement des connaissances se heurte aux risques et inconvenients encourus par les individus sujets de recherche. La necessaire conciliation entre l’interet individuel et l’interet collectif a introduit la necessite d’un droit de regard exterieur a la science, seul capable de legitimer l’implication de sujets humains. La regulation qui en decoule s’articule autour de trois piliers : le consentement libre et eclaire du sujet de recherche, la proportionnalite des risques ou inconvenients et des avantages escomptes, puis la repartition equitable des fardeaux et benefices. C’est en fonction de ces trois principes de respect de la personne, de bienfaisance et de justice, que l’evaluation ethique des Comites d’ethique de la recherche autorise ou non la realisation d’une recherche. Une fois obtenue, cette autorisation ne garantit toutefois nullement que les conditions demeurent identiques tout au long de la recherche. En fait, il est certain qu’elles ne le seront pas : la recherche produit de nouvelles donnees, resultats et effets secondaires notamment, la situation personnelle des sujets evolue tandis que l’environnement meme de la recherche est soumis a des aleas financiers, administratifs ou autres. Comment faire alors pour que les conditions initiales ou, plutot, l’esprit de ces conditions soit respecte ?

We measured glycine release from ([2-3H]glycine)-labelled GSH and glucose formation from maltose incubated with rat kidney whole cortex homogenate, thin cortex slices or collagenase-treated tubule fragments. Liberation of glycine was inhibited (74-83%) by serine borate (20 mM), indicating a gamma-glutamyltransferase-dependent hydrolysis of GSH. In whole cortex homogenate, the GSH cleavage activity was 17.4 +/- 0.6 nmol GSH degraded/mg protein per min (mean +/- S.D.); cleavage activity by intact slices was 3.5 +/- 0.7 (P less than 0.001 relative to whole cortex homogenate) and in tubule fragments 9.4 +/- 0.8 (P less than 0.001). Homogenizing the tissue preparation increased cleavage rate in slices about 4-fold (12.4 +/- 2.9; P less than 0.005 relative to intact slice) but did not change the rate in tubule fragments (9.8 +/- 0.5). Maltose cleavage activity in whole cortex homogenate was 512 +/- 22 nmol glucose formed/mg protein per min, in slices 162 +/- 12, and in tubules 884 +/- 48. These findings imply that substrate in the incubation medium has a limited access to the luminal membrane of cortex slices but not of tubule fragments. They further imply that basolateral membrane is preferentially exposed in the slice preparation.

The initiating factor(s) which triggers compensatory renal growth (CRG) or the nature of regulator(s) activated following the loss of kidney mass is still unknown. The existence of a negative feedback mechanism [1–3] and of stimulating factor(s) present in normal urine [4, 5] and plasma of unilaterally nephrectomized mammals [6–10] have been suggested. The involvement of the endocrine system, cyclic AMP, and cyclic GMP has also been considered [11–13].

The endoplasmic reticulum (ER) of the columnar cells of the rat jejunum was studied with a specific block-staining technique and standard transmission electron microscopy. A new three-dimensional model, based on the analysis of stereo pair photographs, is proposed; this model suggests that the endoplasmic reticulum may constitute a transcellular route. Thick sections (0.5–1 μm) of columnar cells were made after a 5-day impregnation with osmium tetroxide and were examined by standard transmission electron microscopy at 80–100 kV. The evolution of the ER during the cellular ascent of cells from the crypt to the top of the villus is toward a greater complexity. At the base of the crypt of Lieberkuhn, no definite organization is noted, and most often only the nuclear envelope and canalicular elements are stained. The endoplasmic reticulum of the mature columnar cells forms a continuous network of canaliculi and fenestrated saccules; it extends from the apex, below the microvilli, to the lateral and basal plasma membranes, and sends many projections to the nuclear envelope. In the basal part of the cell, below the nucleus, the ER consists mainly of tubular canaliculi, whereas mostly saccules, are observed in the supranuclear part. The canaliculi have a diameter, of 40–60 nm. Fenestrated saccules appear to form a continuous tubular structure surrounding mitochondria; the saccules have a thickness of 25–40 nm and possess irregular perforations of 35–60 nm. Finally, in some cells, the endoplasmic reticulum seems to show functional differences as reflected by the absence of reaction in cells adjacent to well-stained cells in the same part of the villus; thus the osmium impregnation technique appears to be a valid tool for studying the ER organization.

Loading and unloading experiments using intestinal sacs and renal cortex slices were undertaken to ascertain the role of amino acid efflux in cycloleucine-induced amino-aciduria. The presence of cycloleucine, lysine, or valine on the luminal or antiluminal side of the intestine caused an increased leakage of [14C] cycloleucine, [14C] lysine, and [35S] cystine from the tissue. Similar results were obtained when using kidney cortex slices, except for cystine efflux. The latter phenomenon was inhibited by cycloleucine and lysine. Data, also obtained with renal cortex slices, suggest that cystine and cysteine are recognized by different transport sites although one (the oxidized form) may be typically extracellular and the other (the reduced form), intracellular. A comparison of these data with previous works done in our laboratory14 shows that cycloleucine affects efflux less than influx and further suggests that in rats given cycloleucine, renal transport is impaired only at the brush border level for cystine and at both luminal and antiluminal membranes for dibasic amino acids.

This report describes experiments aimed at demonstrating the potential of the submillimetre laser in the field of nondestructive material testing. Most of the research has concentrated on paper properties, such as sheet density, moisture content, and fibre orientation, but other materials have also been tested. The results show that this type of laser is very well suited to the measurement of various physical properties of dielectric sheet materials.

The spatial organization of endoplasmic reticulum (ER) was examined in all segments of rat nephron. Tissues were fixed with glutaraldehyde, impregnated "en bloc" with osmium tetroxide, prepared for and examined by standard (80-100 kV) and high voltage (1 mEV) transmission electron microscopy. In all proximal tubule cells, ER forms a continuous and extensive network of canaliculi and abundant fenestrated saccules which surround mitochondria and cytoplasmic bodies; the cage-like structure of the fenestrated saccules was most evident around the spherical mitochondria of the S3 segment. In the cells of the distal straight and convoluted tubules, the network consists mostly of canaliculi with rare non-fenestrated saccules. The ER network of canaliculi is particularly rich in intercalated cells, in contrast with its rudimentary appearance in the adjacent principal cells of the collecting tubule. In fact, in these cells there are few isolated ER cisternae and they are rarely impregnated. The nuclear envelope is well impregnated in most cells throughout the various segments. Segmental variations in ER organization and its relative abundance are most likely related to the well, established functional heterogeneity of the nephron segments. Moreover, the extensive and unique organization among mitochondria, ER and the basolateral membrane suggests that these three organelles function as a unit which is related to active electrolyte transport. In addition, because of its transepithelial organization, ER may well constitute a transcellular pathway for molecules.

The morphologic interrelationships between mitochondria, the endoplasmic reticulum (ER) and other organelles were examined in rat kidney cells by stereomicroscopy of thick sections (0.3-1.0 micron) using either standard transmission (80-100 kV) or high voltage (1 mEV) electron microscopy. Mitochondria fit into three different categories: (1) elongated cylinders observed in S1 and S2 segments; (2) irregular lamina in the cortical ascending limb or plates in the distal straight and convoluted segments; (3) small spheres or short rods mostly in intercalated and principal cells of the collecting tubule. The chondrioma occupies a large volume in all cells except in the thin limb and in principal cells of the collecting tubule. This volume occupied by the chondrioma is likely to be related to metabolic functions, but its polymorphic configuration could also be explained by a passive adaptation of the mitochondria to the space left by the basilar membrane infoldings and the ER network, which was found to have an extensive three-dimensional organization which varies, as for the mitochondria, with the cell type. In fact, in the proximal nephron, mitochondria surrounded by the ER and the plasma membranes appear to form a functional unit. Organelle interrelationship is extensively modified during ontogeny or under hormonal influence. Disruption in organelle relationships or in their motility could probably have far reaching consequences which would be more deleterious than the pathological lesions observed at the level of a single organelle. The extent of the disassembly can be fully explored only with thick sections and stereomicroscopy.

This paper describes a method to measure DNA synthesis in the jejunum. Everted rings of rat jejunum were incubated in the presence of [3H]thymidine. The specific activity of jejunal DNA was assayed at the end of incubation. This method was found to be valid when (1) incubation time was 30 min, (2) [3H]thymidine concentration was 90 ng/ml, and (3) paired flasks containing four, respectively, contiguous rings were compared.This method was used to investigate the existence of an intestinal chalone. An aqueous extract (S-105) of rabbit small intestine mucosa was prepared and tested for DNA synthesis inhibition in jejunum. A significant inhibition was noted, which was an hyperbolic function of the quantity of extract present in the media. The study of S-105 inhibition on other organs (kidney, liver, colon) failed to demonstrate organ specificity. However, aqueous extracts from intestinal organs were found to exert a greater inhibition than aqueous extracts from other organs. It is suggested that S-105 contains other nonspecific inhibitory fractions; our data prove the necessity of an extensive purification to demonstrate the existence of a specific chalone that regulates intestinal cell proliferation.

The assignment of airplanes to terminal gates should take into account not only the physical constraints of the terminal, but also the incoveniences suffered by the transporter and the travellers when a craft has to be serviced away from the terminal. With this in mind, it is preferable that the number of airplanes assigned to a service area away from the terminal, rather than directly placed at a terminal gate, be minimized. Once this problem has been formulated in the form of a linear programming model with binary variables, a heuristic method is applied to find the best solution.

A new side-product, succinohydroxamic decanoic anhydride, was isolated from the reaction mixture during the acylation of lysine by succinimidyl decanoate in the presence of aqueous sodium hydroxide. Laurie and palmitic acid derivatives were also obtained. It is shown that these compounds can be used for acylation of amino acids. The hydroxamic acid derivatives were also detected when the acylations by succinimidyl esters of fatty acids were carried out under anhydrous conditions. Preparation of N-lauroyl-L-tyrosine methyl ester from tyrosine methyl ester and succinimidyl laurate is also described.

We investigated the process of neonatal hyperprolinuria in dog and rat. Plasma proline varied only 2-fold in the puppy whereas prolinuria increased up to 12-fold from birth to the 10th day declining thereafter to reach adult values (

Three-dimensional characteristics of the mitochondria of the rat nephron. We propose a new model for the mitochondrion of the proximal and distal nephron. The introduction of a new block-staining technique allowed us to observe mitochondria in thick sections (0.5 to 1.5 µm) with a standard transmission electron microscope (80 to 100kV). Combined with stereomicroscopy and serial sections, the thick section offered a three-dimensional view of the chondriome. After glutaraldehyde fixation, rat kidney blocks were immersed in a double-lead and copper citrate solution, which stained mitochondria selectively. Mitochondria were observed to anastomose, branching was evident, and many laterial connections were seen. In cells of both the proximal and distal tubules, mitochondria were observed to extend into the cytoplasm in various directions. In the apical region of both distal and proximal tubules, mitochondria appeared to be small, not numerous, and rarely branched, which corresponds to their classical aspect. The block-staining technique thus confirms what is generally accepted. At the basal part of these cells, however, the spatial morphology of the chondriome appeared quite different from the classical description. In the distal tubule, the chondriome often had the appearance of an irregular lamina to which cords or pseudopods were attached that extended towards various cytoplasmic areas. The extent of branching in the cells of the proximal convoluted segment was more difficult to assess because of the interdigitations of neighboring cells. The chondriome seemed to be made of a few giant ramifying mitochondria and isolated small ones, thus suggesting the possibility of two populations of mitochondria in the nephron of the rat. Caracteristiques tridimensionnelles des mitochondries du nephron du rat. La recente technique de coloration sur bloc nous permet d'etudier des coupes epaisses (0,5 a 1,5 µm) a l'aide d'un microscope electronique standard (80 a 100 kV). Combinee a la coupe seriee ou a l'examen de couples photographiques, la coupe epaisse permet une vue tridimensionnelle des mitochondries. Apres fixation au glutaraldehyde, les blocs de tissu renal sont immerges dans une solution de citrate double de cuivre et de plomb qui colore les mitochondries de facon elective. Les mitochondries paraissent anastomosees, de nombreuses branches laterales etant bien visibles. Dans les cellules proximales et distales, les mitochondries envoient des interdigitations dans toutes les directions. Dans la region apicale des tubules proximaux et distaux, les mitochondries semblent petites, peu nombreuses, et rarement branchees ce qui correspond a leur aspect classique. La technique de coloration sur bloc confirme donc ce concept generalement accepte. Mais dans la partie basale de ces memes cellules, la morphologie spatiale du chondriome est bien differente de la description classique: dans le tubule distal, il apparait comme une lame centrale gaufree irreguliere sur laquelle sont attches des "pseudopodes" qui vont dans plusieurs directions. Le meme type de ramification semble exister dans le nephron proximal mais leur importance est plus difficile a evaluer a cause des interdigitations entre les cellules voisines a ce niveau. Il semble donc que le chondriome consiste en quelques mitochondries geantes ramifiees et quelques petites mitochondries isolees, ce qui suggere l'existence de deux populations de mitochondries dans le nephron du rat. Comme consequence a notre etude, nous presentons une morphologie nouvelle du chondriome des cellules tubulaires proximales et distales du nephron.

Early histological studies of the small intestine revealed the presence of high mitotic activity in the crypts and the absence of cell proliferation in the villi. This mitotic activity appeared to take place in response to damage of the intestinal epithelium caused by the luminal content (toxin, bacteria) of the small intestine (Patzelt, 1936). Bizzozerro (1888) postulated that cells migrate from crypts to villi, resulting in the repair of toxic and bacterial damage of the epithelium.

The injection of cycloleucine (1-aminocyclopentanecarboxylic acid (ACPC)) into rats produces a hyperexcretion of dibasic amino acids and cystine, an aberration resembling cystinuria. This may constitute a model of experimental cystinuria, and the transport of amino acids involved in this disease was studied with the techniques of everted intestinal sacs (in vitro) and microinjections into renal tubules (in vivo). In everted sacs from normal rats, there was a decrease in transfer and in accumulation of L-cystine (0.03 mM), L-lysine (0.065 mM) and L-valine (0.065 mM) when ACPC was on the mucosal (luminal) side. Dibasic amino acids such as L-ariginine and L-lysine caused a similar inhibition of the transport of L-cystine. However, when ACPC was on the serosal (antiluminal) side, a lesser effect was noted while arginine and lysine had no effect. Intestinal sacs from treated rats (ACPC, 300 mg/kg × 3 days) transferred and accumulated as much L-cystine as those from control rats. The interaction between cycloleucine and L-cystine was competitive at the luminal and non-competitive at the antiluminal side of the intestine. Cycloleucine inhibited L-lysine transport in a non-competitive fashion at either side of the intestine. L-Lysine also interacted in a non-competitive fashion with L-cystine transport at the luminal membrane. In proximal convoluted tubules, the presence of L-arginine or ACPC caused a decrease in the transport of L-cystine and L-lysine. L-Valine exerted no effect. Furthermore, L-lysine and ACPC did not impair the reabsorption of L-valine significantly.These results suggest a functional heterogeneity between luminal and antiluminal membranes of renal and intestinal epithelia and the existence, at both membranes, of different transport sites for cystine and dibasic amino acids.

Publisher Summary Ontogeny represents intensification of specific transport systems. It is applied to postnatal changes in the renal handling of proline and glycine. Increasing single-nephron filtration accounts for increasing iminoglycinuria in the early postnatal period. This chapter presents that backflux from immature distal tubule epithelium is not a source of neonatal iminoglycinuria. Mature pars recta accumulates amino acids avidly and, if this phenomenon occurs in the immature nephron also, it is possible that backflux of intracellular amino acids from this segment contributes to neonatal iminoglycinuria. The specific schedule of intensification characterizes the maturation of proline and glycine reabsorption. The chapter reviews that a mosaic of events contributes to the ontogeny of prolinuria. The proliferation of the brush-border membrane and lengthening of nephron segments change the general parameters of reabsorption, while specific intensification of selective carriers, changes in permeability, and oscillations of intracellular metabolism each contribute to the specific schedule of ontogeny.

The maturation of the endoplasmic reticulum (ER) of rat kidney tubule cells was studied with an osmium impregnation technique. Thick sections (0.3-0.6 micron) of kidney tissue were made after a five-day impregnation with osmium tetroxide and examined by standard transmission electron microscopy at 80-100 kV. Studies were performed on rat foetuses from 18-21 days of gestation, on newborns, and on 2-20 day old animals. At the undifferentiated stage, only a small percentage of the tubule cells were impregnated; in these, the perinuclear sac was stained and a few nuclear pores were already seen. Rudimentary, but thick canalicular projections seemed to originate from the perinuclear sac and become more extensive with maturity. Flattened saccules appeared later and fenestrations were seen in proximal tubule cells only when they seemed to have reached their functional specialization. In some cells, only the Golgi apparatus was stained. In the distal tubule cells, there was also progressive formation of a network consisting first of canaliculi and later of saccules which were rarely fenestrated. The osmium impregnation technique appears to be useful as an index of the ER organization development.

The ontogeny of the chondriome was studied in the developing kidney of fetuses and newborn rats and compared to its maturation in jejunum cells of adult rats. The tissues were immersed in a double lead and copper citrate solution which stains mitochondria selectively. Thick sections (0.3-0.5 micron) were observed with a standard transmission electron microscope (80-100 kV). Mitochondria have in developing cells a shape different from those in mature cells and seem to increase in number and volume during development. In the undifferentiated stages of both jejunum and nephron, the mitochondria are small, spherical and scattered throughout the cytoplasm with no particular orientation. As jejunal cells migrate towards the villus tip, the mitochondria orient themselves in the apical-basal direction; those of the proximal nephron become parallel to the lateral cell membranes. The morphological communications found in adult renal cells are much less prominent in the jejunum. With maturation, the close association between membranes, mitochondria and the endoplasmic reticulum takes place in both epithelia. Our studies suggest that the mitochondrial mass is increased by a continuous process of addition of sub-units and that the chondriome development appears to be more analogous to the growth, differentiation and modification of the endoplasmic reticulum system. The chondriome also seems to reach a certain stage of development before the onset of the organ function.

Microinjections of L-[14C]arginine (2.9 mM) and L-[14C]ornithine (3.4 mM) were made into renal proximal tubules of rats in the presence of methionine sulfoximine (MSO) (10, 20 mM), ATP (10 mM), and MgCl2 (20 mM) together. Absorption of both labelled amino acids dropped, respectively, by 31.1 and 49.1% compared with control microinjections. The MSO alone or ATP plus MgCl2 had no effect. These data suggest that the inhibition by MSO plus ATP plus MgCl2 is not due to direct competition between MSO and dibasic amino acids but rather to suppression of the renewal of intracellular glutathione. Such an effect is discussed in comparison with cycloleucine inhibition of dibasic amino acid transport. Addition of exogenous glutathione to microinjectates did not reverse either type of inhibition. This study shows that while intracellular glutathione may affect amino acid transport, extracellular glutathione has no effect.