Moisture measurement: a new method for monitoring freeze-drying cycles.

Quality of the final product largely depends on the freeze-drying process. In turn this largely depends on an adequate control of the amount of residual moisture after freeze-drying. Measuring this amount in the chamber of the freeze-dryer to determine the end point of sublimation and the end point of secondary drying provides a reliable control with regard to the methods traditionally used (for example rapid increase in product temperature). The purpose of this study is to evaluate the benefits and disadvantages of the different methods recommended for the monitoring of a freeze-drying cycle. Two systems for the measurement of the moisture in the freeze dryer are evaluated here: the Pirani vacuum gauge, and the moisture sensor. The moisture sensor appears to be the most sensitive and reliable way of determining both the end of sublimation and the end of secondary drying of the full load batch when placed on a freeze-dryer. The immediate benefit for the industry is to allow to scale-up without the risks of under or over estimating the freeze-drying cycle.

Antigenic variations of Candida albicans in vivo and in vitro--relationships between P antigens and serotypes.

Serum samples from patients with candidosis and from rabbits experimentally infected with serotype B C. albicans strains consistently showed higher antibody titers against Candida strains with serotype A antigens than strains with serotype B antigens, in indirect fluorescent antibody tests. When sera from rabbits infected with C. albicans serotype B strains were absorbed with blastospores of the homologous strain they continued to react against strains of C. albicans serotype A and a C. tropicalis strain with serotype A antigens. Serotype A-specific antisera reacted against tissue forms of C. albicans serotype B in vivo and against serotype B germ tubes, but not their parent blastospores, in vitro. These findings suggest that C. albicans B serotype cells may sometimes express, in vitro or in vivo, one or several antigens so far considered as specific of serotype A. The results have implications for the classical concept of C. albicans serotypes and for the serological diagnosis of candidosis in relation with the previously described strain P variable antigens.

Endoprotease in Plasmodium yoelii nigeriensis.

1. P. yoelli nigeriensis has an acid endoprotease (cathepsin D) and an endoarylamidase. 2. The acid endoprotease is specific towards haemogloblin. It is found in 2 molecular forms, of molecular weight 100,000 and 50,000. It is inhibited by hematin and pepsatin. 3. In mouse normal red blood cells we find an acid protease having physico-chemical properties similar to those of the enzyme present in P. yoelii nigeriensis extracts, except as regards the pHi. 4. In parasite extracts there exists an enzyme active on the synthesis substrate N-acetyl alanine 4 nitro anilide. The main properties of this enzyme have been determined. 5. This enzyme must be also involved in the mechanism of haemoglobin degradation.

[Interaction of chloroquine with ferriprotophorphyrin IX. Nuclear magnetic resonance study]. / Interactions de la chloroquine avcc la ferriprotoporphyrine IX. Etude par résonance magnétique nucléaire.

Chloroquine is still the antimalarial drug which is the most utilized. Nevertheless the molecular mode of action of this drug is not very well understood. When mouse erythrocytes injected with Plasmodium berghei are exposed to chloroquine, the first biochemical event is rapid accumulation of the drug. This process is energy dependent, saturable and competitively inhibited by drugs of the same therapeutic class (Quinine, Amodiaquine, Mefloquine). Receptors for chloroquine have been proposed for the process of accumulation. The nature of the chloroquine receptor is presently the subject of debates. The latest hypothesis proposed by Chou and coll. [12], is that ferriprotoporphyrin IX, formed by the degradation of hemoglobin by the parasite, binds to chloroquine with a dissociation constant of 3.5.10(-9) M. We studied here the molecular interactions between these two species by Proton Nuclear Magnetic Resonance in order to elucidate the nature and the geometry of were undertaken. The perturbations of the NMR spectra of chloroquine (10(-2) M) induced by addition of hematin or hemin were measured. Two types of measures were undertaken. The first study carried out in organic solvent (DMSO) has shown that the interaction occurred between the acidic functions of hemin and the side-chain nitrogen of chloroquine. The iron atom was not implicated in this process. The second study carried out in aqueous medium (phosphate buffer; 0.1 M; pH = 7) allowed us to demonstrate that chloroquine is able to intercalate into a polymer of hematin. The quinoleic nucleus of chloroquine was intercalated between two dimers of hematin as shown by the broadening of the signal of the quinoleic protons due to very large increase in the correlation time. Finally it was shown that chloroquine is associated as a dimer in aqueous medium by hydrophobic interactions. The association constant is 5.5 M-1.

[Ultrastructural and cytochemical aspects of regenerating "Candida albicans" sphero-protoplasts (author's transl)]. / Aspects ultrastructuraux et cytochimiques de la régénération des sphéro-protoplastes chez Candida albicans.

Subcellular modifications associated with sphero-protoplast regeneration of Candida albicans were followed with the electron microscope. After 30 min of regeneration the ultrastructural study revealed a considerable proliferation of plasmalemma invaginations and an abundant synthesis of glycogen in association with an extension of the Golgi apparatus/endoplasmic reticulum system. Later, the inflection of these invaginations and their fusion with the plasmalemma lead to a rejection of cytoplasmic areas in the cell wall. Glycogen-like particles so released in the wall were distributed in clearly delineated layers. The incorporation of cytoplasmic material through the intermediary of the plasmalemma constituted a mechanism believed to mediate the reconstitution and thus the integrity of the newly-forming cell wall.

Localization of chitin in the cell wall of Candida albicans by means of wheat germ agglutinin. Fluorescence and ultrastructural studies.

Cytochemical localization of wheat germ agglutinin binding sites in the cell wall of Candida albicans was investigated with fluorescence and electron microscopy. Various analytical techniques were employed in order to obtain a good penetration of the cytochemical markers, glycosylated horseradish peroxidase or glycosylated ferritin. In blastospores sectioned by cryostatic methods, a weak and continuous labelling of the blastospore periphery was observed with peroxidase, whereas bud scars and inner cell wall areas were labelled with ferritin. Following enzymatic treatment with pronase whose efficiency was followed by the periodic acid-thiocarbohydrazide -- Silver proteinate technique, the inner cell wall layers of bud are strongly stained with both fluorescein and the reactions products of peroxidase. After pronase-chitinase treatment, fluorescence was observed only in the mother cell wall. Finally, ultrathin glycol methacrylate sections showed a labelling both in inner and outer layers. All these results suggest that chitin was essentially distributed in the inner wall layers near the plasmalemma and in a smaller amount in outer wall layers. On the basis of the present findings, a hypothesis of wall assembly is proposed.

[Ultrastructural organization of "Candida albicans" blastospore cell wall: localization of chemical and antigenic components (author's transl)]. / Architecture pariétale des blastospores de Candida albicans: localisation de composants chimiques et antigéniques.

Various ultrastructural methods were applied to study the localization of chemical and/or antigenic components of Candida albicans blastospore cell wall. They concerned: PATAg reaction for the detection of polysaccharides on ultrathin sections associated with enzymatic digestions or polysaccharide extraction; the indirect immunoferritin method on intact cells; the indirect immunoperoxidase method on ultrathin section of water soluble embedding medium; the indirect immunofluorescence test, using patients and experimental sera. The cytochemical results confirmed a previously described eight layer organization. The immunocytochemical methods, also in agreement with this stratification, showed in addition to external structures that the layer located near the plasmalemma must be considered as an important antigenic area. The mannans responsible for antigenic differences between strains of C. albicans and namely those supporting the serotype A activity were shown to be, at least, distributed among two of the described peripheral layers.

[Contribution to the study of nervous system in larval and adult forms of Schistosoma mansoni Sambon, 1907 (Trematoda Digenea). II. Role of serotonine and dopamine (author's transl)]. / Contribution a l'étude du système nerveux des formes adultes et larvaires de Schistosoma mansoni Sambon, 1907 (Trematoda Digenea). II - Rôle de la sérotonine et de la dopamine.

This study provides details concerning the localization and role of 5-HT and DA in Schistosoma: 1) 3H-5HT is incorporated selectively by the nerve fibers containing dense granules measuring 820 +/- 20 A (type 2 granules), combined at times with other structures; the presence of "cold" dopamine in the environment does not alter the incorporation; 2) 3H-DA is also incorporated in vitro by the nerve fibers and occasionally by the muscle fibers of the adult Schistosoma; 3) neither the intraovular miracidium, the first and second generation sporocystes, nor the intrasporocystic cercariae appear to incorporate the 3H-5-HT or the 3H-DA, under our working conditions. The two amines are, however, incorporated by the hepatopancreas of Biomphalaria glabrata and the 3H-5-HT produced marking on certain neuromuscular zones of the tentacle.

[An ultrastructural study of spermatogenesis in Trichinella spiralis Owen 1835 (Nématode Trichuroide) (author's transl)]. / Etude ultrastructurale de la spermatogènese chez Trichinella spiralis Owen 1835 (Nématode Trichuroïde).

The ultrastructural study of spermatogenesis in T. spiralis demonstrated the main characteristics of the male germ cells in the class Nematoda, i.e. lack of flagella, lack of reconstitution of the nuclear envelope after the meiotic divisions, and atypical structure of the centriole. The spermatozoon of T. spiralis was compared with previous classifications of the nematoda spermatozoa.

[Morphology and infectivity of gametocytes of Plasmodium inui]. / Morphologie et infectivité des gamétocytes de Plasmodium inui.

The authors report biomorphological changes of Plasmodium inui gametocytes during the natural infection of spleenless Macaca fascicularis. The infection was controlled up to the 42th day by smears produced by pricks into their ears (P.O.) and on blood taken at the same time by A. stephensi (P.M.). The first oocystes appeared on the 8th day after the infection in mosquitoes fed on the monkey parasitised in the eight day after splenectomy, as gametocytaemia was not detectable yet in the P.O. smears. The infectivity of gametocytes is highest on the 13rd day for a 152/10(4) parasitaemia. The first sporozoites appeared on the 18th day at 25 degrees C after the infecting meal. The sporozoites were infecting for a second monkey. Four morphological types (O, I, II and III) gametocytes were identified. They corresponded to the same types previously described in rodent Plasmodium. The maximum of infectivity coincided with a sudden increase in mosquitoe macrogametocytaemia; on the other hand the infectivity was very weak during the following peek of macrogametocytaemia which corresponded however to the maximum of parasitaemia (1 318/10(4) 18 days after splenectomy). When infectivity was important, there was a greater number of type O and I gametocytes in P.M. than in P.O. Eventually, the behaviour of P. inui gametocytes is, for the mainly, almost the same as that of rodent Plasmodium. However, it is to be noted that the identification of the 4 morphological types in P. inui is easier in macrogametocytes than in microgametocytes. The reverse had been observed in rodent Plasmodium.

[Ultrastructural study of oogenesis in Trichinella spiralis (author's transl)]. / Etude ultrastructurale de l'ovogénèse chez Trichinella spiralis.

The ultrastructural study of oogenesis in T. spiralis makes it possible to subdivide the oocytic growth into 2 phases: a first phase is characterized by an intense nucleolar activity and the transfer of nuclear material to the cytoplasm; a second phase during which the cytoplasmic mass increases and energy reserves (glycogen, lipids) appear. The oocyte does not contain any protein vitellus.

[Changes of serum lipoproteins during the course of human malaria (author's transl)]. / Modifications du lipoprotéinogramme au cours du paludisme humain.

Triacylglycerides (TAG), total cholesterol (TC) and serum lipoproteins (SLP) were studied during the course of 12 cases of human malaria and one case of simian inui malaria. The erythrocytic schizogony induced quickly an increase of TAG, a decrease of TC and modifications of SLP such an increase of VLDL parallel with a decrease or a disappearance of HDL. These modifications, always clear-cut, were not correlated with the intensity of parasitaemia or the species of Plasmodium. They were transient but longer than those described in connection with experimental rodent malaria. The changes of HDL could be associated with defective triglyceride removal of the plasma compartment due to an inhibition of the lipoprotein lipase induced by the parasite.

[Effect of glucose and nitrogen concentrations on the morphology of Candida albicans and the formation of chlamydospores in synthetic culture media]. / Influence de la concentration du glucose et de l'azote sur la morphologie de candida albicans et la formation de ses chlamydospores dans un milieu de culture synthétique.

Candida albicans was grown in the darkness, at 28 degrees C, in a synthetic medium in which glucose and nitrogen concentrations were varied. Numeric appraisal of the chlamydospore index was possible only in the medium where glucose concentration was 0,08 g/1 or less. When the glucose concentration raised, pseudomycelial thalli bore numerous chlamydospores but sometimes also chains of cells with a dense granular content. These thalli bud yeast cells which separate and bud again in the medium. The different morphological aspects of the cultures are decribed, illustrated and classified according to the glucose and nitrogen concentration of the medium.

[Not Available]. / Les phénomènes immunitaires de la syngamose expérimentale. II. Mise en évidence et cinétique de l'immunité à médiation cellulaire.

A kinetic in vitro study of cell mediated immunity (C.M.I.) has been made in the turkey and the chicken experimentally infected with Syngamus trachea. The method used for this purpose was an indirect test based on the inhibition of macrophage spreading. In the turkey, C.M.I. appeared by the 4th day following the infection, reached its maximum by the 15th day, then decreased slowly and disappeared by the 13th week. Reinfection induced a C.M.I. significantly greater than those observed in the case of a single infection. In the chicken also, C.M.I. appeared by the 1st week but its maximum was reached earlier and had disappeared as early as the 5 th week. The results we have observed are in agreement with those previously reported in other parasitic models such as schistosomiasis caused by Schistosoma mansoni and trichinellosis.

Experimental study of resistance to infection by Trichophyton mentagrophytes: demonstration of memory skin cells.

The mechanisms governing the development of local immunity in experimental dermatophytosis were studied by injecting intravenously trichophytin in guinea pigs cured of a prior Trichophyton mentagrophytes infestation. Dermal cell modifications were observed which were greater in the healed zones than in those not affected during the prior dermatophyte inoculation. These modifications included lymphocyte activation and accumulation and an accumulation of basophilic leukocytes. These observations suggest that after an acute dermatophyte infection heals, immunocompetent cells remain which are more numerous at the sites of lesions and that these cells would be responsible for the increased rate of elimination of the fungus during a reinfection. This hypothesis is discussed in the framework of the relationships observed in dermatophyte infections between delayed type hypersensitivity and resistance.

Production of Eremofortins A, B, and C Relative to Formation of PR Toxin by Penicillium roqueforti.

The production of various eremophilane-type sesquiterpenes by Penicillium roqueforti strains has allowed us to propose a biochemical pathway for PR toxin synthesis. A time-course study of P. roqueforti metabolite production by high-performance liquid chromatography was performed to check this hypothetical pathway. The results obtained suggested that eremofortin C was the direct precursor of PR toxin in the P. roqueforti cell. Attempts to determine the amount of PR toxin in the mycelium failed. It was shown that the absence of PR toxin in mycelium was due to its instability during the extraction procedure.

[Chlamydosporulation in "Candida albicans". Course of the morphogenesis; influence of light and sowing density (author's transl)]. / Chlamydosporulation de Candida albicans: déroulement de la morphogenèse; influence de la lumière et de la densité d'ensemencement.

Candida albicans is cultivated on rice cream decoction with glucose for chlamydospore production. A developmental stage refered as readiness is recognized. At this stage, the pseudomycelial thalli are able to produce chlamydospore in water without further stimulus by the sporulation medium. The greater the inoculum, the earlier appears the readiness. During the growth phase up to the readiness, the light is inhibiting the chlamydosporulation and favorising the yeast development. After the readiness, light still inhibits chlalmydospore formation.