Reactivación de la enfermedad de Chagas después de trasplante autólogo de progenitores hematopoyéticos. Reporte de caso y revisión de la literatura

Introduction:

Chagas disease is an endemic parasitic infection in Latin America transmitted by triatomines. It is associated with risk factors such as poverty and rurality. After acute infection, a third of patients will present target organ involvement (heart, digestive tract, central nervous system). The remaining two thirds remain asymptomatic throughout their life. Pharmacological immunosuppression breaks the balance between the immune system and the parasite, favoring its reactivation.

Clinical case:

We present the case of a 58-year-old man from a Colombian rural area with a diagnosis of multiple myeloma refractory to the first line of treatment who required a new chemotherapy scheme and consolidation with autologous stem cell transplant. During the post-transplant period, he suffered from febrile neutropenia. Initial microbiological studies were negative but the peripheral blood smear evidenced trypomastigotes in blood. With a diagnosis of acute Chagas disease in a post-transplant patient, benznidazole was started. The evolution of the patient was satisfactory.

Conclusions:

Positive serology prior to transplantation makes it necessary to rule out reactivation of the pathology in the setting of febrile neutropenia. More studies are required to determine tools for estimating the probability of reactivation of the disease and defining the best cost-risk-benefit relation for the prophylactic therapy.     

Differenciation cellulaire et composés sulfhydrylés acido-solubles de la racine de Lens culinaris Med.

Cell differentiation and acid-soluble sulfhydryl compounds in the root of Lens culinaris. Med. — The content of acid-soluble sulfhydryl compounds (SH + S-S) is determined amperometrically in tissues of the Lens root. Two distinct zones are analysed: first the meristematic one (0 to 1.6 mm from the tip) and secondly the elongating one (1.6 to 3.7 mm). Measurements concerned the first 80 hours of the root growth. SH/S-S ratio is minimum in the meristematic ZONE. Connections seem to exist between the growth rate and the amount of SH compounds in the elongating zone. These facts suggest that the increase of cytoplasmic SH is associated with the reduction of protein-disulfur-bridges, which account for t he intermicrofibrilar bindings in the cell wall. The effects of auxins (indoleacetic acid and naphtylacetic acid) treatments are also studied. They are strictly localized in the apical zone and their intensity depends upon the auxin concentration. SH-level is rising: this is due partially to a reduction of acid-soluble S-S.     

Variations du taux en composés sulfhydrilés acidosolubles de tissus cultivés in vitro

Variations of the Level of the Nitrogen and Thiol Groups in Tissues Culture.—Distribution of nitrogen and thiol compounds was analysed in the fragments of carrot roots cultivated in vitro. A typical gradient of –SH groups was observed: high level in the callus, low level in the base of the fragment (in contact with the medium). In discontinuous light, callus—which have a great amount of chlorophylls—contain less sulfhydric compounds than in continuous dark. With increasing age of the tissues, the concentration of the endogenous –SH groups was decreasing. The probable biochemical relations between –SH level, auxin content and auxin-oxidase activity are discussed.     

Etude de quelques propriétés de la phosphofructokinase érythrocytaire de l'homme normal

Human erythrocyte phosphofructokinase was purified 150 fold by DEAE cellulose adsorption and ammonium sulfate precipitation.At pH 7,5 the enzyme exhibits allosteric kinetics with respect to ATP, fructose 6 phosphate, and Mg²⁺.ATP at high concentration acted as an inhibitor and ADP, 5′AMP, 3′,5′, AMP, acted as activators. Both effectors seemed to decrease the homotropic interactions beetween the fructose 6 phosphate molecules.The activators increased the affinity of phosphofructokinase for the substrate (F6P), the inhibitor decreased it.These ligands had no effect on the maximum velocity of the reaction except in the case of ADP.Interactions between the substrates and the effector ligands on the enzyme were considered in terms of the Monod - Changeux - Wyman model for allosteric proteins.With GTP and ITP, no inhibition was observed. At saturing concentration of GTP, ATP still inhibited phosphofructokinase.Both 3′5′ AMP and fructose 6 phosphate increased the concentration of ATP required to produce an inhibition of 50 %.Citrate, like ATP, inhibited phosphofructokinase by binding most likely at the same allosteric site. Erythrocyte phosphofructokinase is inhibited by 2–3 DPG.The study of the relation log V max = f (pH) suggested, that the active center contains at least one imidazole and one sulfhydryl group.     

Modalités de l'inhibition de la croissance et de la synthèse des acides nucléiques des plantules de blé par l'acide abscissique

The growth of wheat seedlings (Triticum sativum) is inhibited by abscisic acid (ABA). The inhibition increases with the concentration of ABA (from 10^-6M to 5 × 10^-5M) and is stronger in the case of coleoptiles and first leaves than in roots. In contrast, naphthaleneacetic acid (ANA), at 10^-5M, exerts its greatest inhibitory effect on the roots. The inhibitory effect of ABA on coleoptiles can be partially overcome by kinetin and to a much smaller degree by gibberellic acid. Neither of these two compounds, at 10^-5M, had any effect on the ABA-induced inhibition of root growth. The RNA and DNA contents per plant organ are considerably reduced after treatment of the seedlings with ABA, particularly in the coleoptiles and the first leaves. The incorporation of uracil-2-¹⁴C and uridine T (G) into RNA of treated seedlings is reduced in the case of coleoptiles and first leaves, but considerably enhanced in roots. The mechanism of the action of ABA is discussed in the light of these results.     

Le Macronucleus Hétéromere de Quelques Ciliés

SUMMARY. In ciliates belonging to the two gymnostome families Chlamydodontidae and Dysteriidae as well as to the order Chonotrichida the macronucleus is composed of two parts which are distinct but in very close juxtaposition. One part, here called "orthomerous," contains granules or microsomes of desoxyribonucleoprotein and several nucleoli; it thus shows the normal structure of a macronucleus of the ordinary type. The other part, "paramerous," contains desoxy-ribonucleic acid diffused, apparently, throughout a homogeneous karyolymph and possesses, in addition, several nucleoli and an endosome of desoxyribonucleoprotein.
The three groups of ciliates under discussion are closely related and constitute an assemblage of forms remarkably evolved. The "heteromerous" structure of their macronuclei must be considered as a secondary acquisition and a differentiation of the "homeomerous" type which characterizes the structure of the macronucleus in most other ciliates.     

Équilibres conformationnels de glucides au niveau de liaisons σ SP-SP: Partie V. Dérivés 2,3,-O-isopropylidène de pyranosides hybrides sp en C-4. Comparaison avec leurs analogues saturés

The conformation in solution of derivatives of methyl hexopyranosides has been studied by n.m.r. The esters of methyl 2,3-O-isopropylidene-α-D-manno- and -talopyranosides as well as their 4-deoxy-4-C-methyl analog having a manno configuration exist mainly in a flattened (^4,0F) chair conformation (⁴C₁). The presence in the talo epimer of the 4-deoxy-4-C-methyl analog of the bulky methyl group on the endo side of the bicyclic system results in a skew form (³S₁). The methyl 4-deoxy-2,3-O-isopropylidene-4-C-methylene-α-D-lyxo-hexopyranosides monosubstituted at C-4′ adopt, in solution, a conformation close to ³S₁, whichever their configuration (cis or trans) at the double bond, as indicated by their allylic coupling constants.     

Dérivés C-glycosyliques : Partie XII. Élaboration de cycles furoxannes,isoxazoles et 2-isoxazoline par l'intermédiaire d'oxydes de nitrile dérivés de sucres

Treatment with a base of hydroxymoyl chlorides derived from sugars led to the corresponding unstable nitrile oxides which, in the absence of nucleophilic or dipolarophilic reagents, dimerize into furoxans. When nitrile oxides are formed in the presence of an excess of acetylenic (or olefinic) dipolarophilic reagents, they give 1,3-dipolar cycloaddition reactions with the formation of the corresponding 3-glycosylisoxazoles (or -2-isoxazolines). The action of nucleophilic reagents such as the alkaline cyanides or ethylmagnesium bromide allows the elongation of the sugar chain by one or two carbon atoms, respectively. The action of ethynylmagnesium bromide on these nitrile oxides gave a mixture of two compounds: an α-ethynyloxime and a 3-glycosylisoxazole; in alkaline medium the former compound can undergo cyclization and transformation into the latter, thus allowing deuterium labeling of that compound.     

Les kystes de dinoflagellés du Crétacé moyen de la marge atlantique brésilienne, le bassin de Santos

Organic dinoflagellate cysts are studied from the sedimentary sequence of hole 1-SPS-14A, drilled during oil exploration in the Santos Basin, Brazilian continental margin. The Ariri and Florianópolis Formations (Transitional sequence) do not contain any dinocysts. The oldest found dinocysts occur at the base of the Drift sequence in sediments, within platform carbonates of the Guarujá Formation. Continuous sea-level rise throughout the late Albian and Cenomanian submerged the carbonate platform with the terrigenous input of the Itanhaém Formation. The transgressive phase reached its peak during the Cenomanian/Turonian transition. Pelites were deposited during oceanic anoxic event (OAE-2), consisting the lower part of the Itajaí-Açu Formation. Normal oceanic conditions re-established in the late Turonian. The Brazilian dinocyst assemblage has tethyan affinities. Some species (i.e., Dinopterygium cladoides, Litosphaeridium arundum, Odontochitina rhakodes and Systematophora cretacea) suggest a middle Albian age for the carbonate platform of the Guarujá Formation. The lower part of the Guarujá Formation was not dated by other microfossils. An uppermost Albian or lower Cenomanian age is suggested for the base of the Itanhaém Formation on the basis of species Palaeohystrichophora infusorioides and Ovoidinium verrucosum. The Cenomanian-Turonian boundary cannot be characterized by dinocysts. Species Atopodinium iuvene, which is known from Turonian sediments in Europe, was found at the top of the Itajaí-Açu Formation. The observed dinocyst bioevents (i.e., last occurrence) are correlated with known foraminiferal, nannofossil and other palynological bioevents. The diversity of the assemblages remains constant throughout the various palaeoenvironments as these are reflected by the Guarujá and Itajaí-Açu Formations, but relative abundances of taxa are variable. Genera Coronifera, Florentinia, Ovoidinium, Spiniferites and Trichodinium are abundant in the carbonate platform assemblages (Guarujá Formation). Genera Cribroperidinium and Cyclonephelium are abundant in detrital sediments (Itajaí-Açu Formation). Only one species (Subtilisphaera guarujaensis n. sp.) is restricted to the carbonate platform environment.