Hydrolytic enzyme activity in rhesus monkey placenta during early gestational malaria : histochemical studies

Background & objectives: Early gestational malaria is found to be more fatal than late gestationalinfection but the pathophysiology of early gestational placenta, the maternofoetal organ responsiblefor maintenance of pregnancy, remains unexplored. Present study dealing with hydrolytic enzymes inearly gestational placenta of rhesus monkeys during Plasmodium cynomolgi infection was anticipatedto provide a better insight into the functional impairment of this organ during early gestationalmaternal malaria.Methods: Experimental monkeys (Macaca multtta) at 2–2½ months of pregnancy were inoculatedwith P. cynomolgi bastianelli. After attaining first peak of parasitaemia the animals were anesthetisedand placentae were collected for histochemical studies. The snap-frozen, cryostat sections weresubjected to histochemical reactions for acid phosphatase and alkaline phosphatase.Results: The placental syncytiotrophoblast showed a loss in alkaline phosphatase activity, while thetrophoblast layers and phagocytic cells of the maternal blood showed increased acid phosphataseactivity during early gestational malarial infection. Morphological damage to the placental tissuewhenever occurred was associated with altered Alk pase activity.Interpretation & conclusion: The altered distribution of Ac pase and Alk pase in malaria infectedearly gestational placenta has been discussed in the light of placental function. It could be concludedby present studies that these malaria induced changes in hydrolytic enzyme activities in monkeyplacenta have a direct bearing on functional and morphological integrity of the placental tissue.These changes are apparently responsible for early gestational foetal death and abortions as reportedin literatur

Oxidoreductases in early gestational monkey placenta during maternal malarial infection : histochemical localisation

Background & objectives: Early gestational malaria is more deleterious than late gestational infection.Still the pathophysiology of maternofoetal organ—the placenta in malaria remains almost unexploredduring early gestation. Present study dealing with oxidoreductases in early gestational placenta duringmaternal malarial infection of Plasmodium cynomolgi bastianellii in rhesus monkeys was anticipatedto provide a better insight into the functional impairment of this organ leading to foetal abnormalities.Methods: Three control and four experimental monkeys (Macaca mulatta) were quarantined for onemonth prior to experimentation. Experimental monkeys at 2–2½ months of gestation were inoculatedwith P. cynomolgi bastianellii. On attaining first peak of parasitaemia the placentae were collectedfrom anesthetised animals. The snap-frozen, cryostat sections were subjected to histochemicallocalisation for 3 (or 17) β-hydroxysteroid dehydrogenase (β-HSD) [3 (or 17) β-hydroxysteroid:NAD (P+) oxidoreductase, EC 1.1.1.51 hydroxysteroid dehydrogenases] and NADPH-tetrazoliumreductase [NADPH : (acceptor) oxidoreductase, EC 1.6.99.1 NADPH-TR]. Comparative microscopyof control and malaria infected placental sections was performed and analysed.Results: A localised decrease in both the enzymes was observed in syncytiotrophoblast layer ofmalaria infected monkey placenta. The areas showing morphological damage of syncytiotrophoblastwere also depicting gross reduction in NADPH-TR activity.Interpretation & conclusion: The altered enzymatic activities [3 (or 17) β-HSD and NADPH-TR] inmalaria infected early gestational monkey placenta have been discussed in the light of placentalfunction. It could be concluded by present studies that these alterations would affect the cellularmetabolism especially steroidogenesis and detoxification process which in turn would affect thenormal development of the foetus as well as maintenance of gestation

Structure, Transport and Magnetic properties in La2x_{2x}Sr2−2x_{2-2x}Co2x_{2x}Ru2−2x_{2-2x}O6_{6}

The perovskite solid solutions of the type La$_{2x}$Sr$_{2-2x}$Co$_{2x}$Ru$_{2-2x}$O$_{6}$ with 0.25 $\leq$ x $\leq$ 0.75 have been investigated for their structural, magnetic and transport properties. All the compounds crystallize in double perovskite structure. The magnetization measurements indicate a complex magnetic ground state with strong competition between ferromagnetic and antiferromagnetic interactions. Resistivity of the compounds is in confirmation with hopping conduction behaviour though differences are noted especially for $x$ = 0.4 and 0.6. Most importantly, low field (50Oe) magnetization measurements display negative magnetization during the zero field cooled cycle. X-ray photoelectron spectroscopy measurements indicate presence of Co$^{2+}$/Co$^{3+}$ and Ru$^{4+}$/Ru$^{5+}$ redox couples in all compositions except $x$ = 0.5. Presence of magnetic ions like Ru$^{4+}$ and Co$^{3+}$ gives rise to additional ferromagnetic (Ru-rich) and antiferromagnetic sublattices and also explains the observed negative magnetization.Comment: Accepted for publication in J. Magn. Magn. Mate

Infrared absorption study of charge ordered La0.5Ca0.5−xSrxMnO3La{}_{0.5}Ca{}_{0.5-x}Sr_{x}MnO_{3} (0.1≤x≤0.5(0.1\leq x\leq0.5

Infrared absorption study has been carried out on a series of half doped manganites, $La_{0.5}Ca_{0.5-x}Sr_{x}MnO_{3}$ $(0.1\leq x\leq0.5)$, with varying magnetic ground state. The charge ordering transition observed in samples with {\normalsize $x\leq0.3$ is accompanied by a mode at $\sim525cm^{-1}$ in addition to the stretching mode at $615cm^{-1}$ and bending mode at $400cm^{-1}$. Phonon hardening is found to occur below the CE - type antiferromagnetic ordering temperature. The value of the insulating gap decreases on doping with Sr from $727cm^{-1}$ to $615cm^{-1}.$}Comment: 14 pages, 5 figures, To appear in Physica