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#32455041   2020/04/29 To Up

Neuronal Differentiation in a Pituitary Macroadenoma with Focal Small Blue Round Cell Morphology: Report of a Rare Pattern.

Ganglion cell-containing pituitary adenomas that are neurofilament protein-positive are the exceedingly rare form of pituitary ganliocytomas. We report a case of a 23-year-old male patient who presented with a clinical picture of acromegaly in addition to raised prolactin level. Histopathology showed areas exhibiting pseudopapillary and solid proliferation of round and monotonous blue cells. The immunohistochemistry showed strong reactivity for synaptophysin and growth hormone and focal reactivity to prolactin. Fibrous bodies are confirmed using cytokeratin immunostain, in keeping with sparsely granulated somatotroph component. The patient remained free of recurrence after one year of radiological follow-up.
Hisham Alkhalidi

2958 related Products with: Neuronal Differentiation in a Pituitary Macroadenoma with Focal Small Blue Round Cell Morphology: Report of a Rare Pattern.

100 μg100 ml.25 ml.

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#32454423   2020/04/21 To Up

BOLD activation during cue induced craving in adolescent inhalant users.

Inhalants are legally available substances, most of them inexpensive, which are often abused by adolescents. Craving causes their continued use and repeated relapses. There is a need to understand the cue-induced craving and the associated neural mechanisms. In absence of any such prior study, the present study compared the hemodynamic changes in brain associated with craving effect in adolescent inhalant users and healthy controls using blood oxygen level dependent (BOLD) mechanism. This was an observational case control study with twelve adolescents, aged 12-18 years, with current use of inhalants as their primary drug, and twelve healthy, age and gender-matched adolescents, with no lifetime use of inhalants. Clinical assessments included Teen Addiction Severity Index and Visual Analogue Scale for craving. Participants abstained from all substances during 48 h prior to fMRI, confirmed by urinalysis. A validated visual cue block paradigm with neutral and craving cues was presented during the BOLD assessments in a 3 T MR system. The inhalant users exhibited BOLD activation in inferior frontal gyrus, inferior parietal lobule, superior occipital gyrus, cingulate gyrus, lentiform nucleus, thalamus, and culmen as compared to control group. The control group exhibited activation of insula as compared to cases. The results may be attributed to visuo-spatial attention, visual perception, working memory, and motivation associated with visual cue reactivity. This preliminary study provides important findings pertaining to activation patterns in response to cue-induced craving among adolescent inhalant users.
Shobhit Jain, Anju Dhawan, S Senthil Kumaran, Raman Deep, Raka Jain

2623 related Products with: BOLD activation during cue induced craving in adolescent inhalant users.

100ug100ug50 ul1 mg25 Bags/Unit100μg5ug2 mg96T100μg100 ul400 ug

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#32453890   2020/05/26 To Up

Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling.

The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination of palladium and a chiral phosphoric acid was investigated by a combined experimental and statistical modeling approach. Experiments to probe nonlinear effects, the reactivity of deuterium-labeled substrates, and control experiments revealed that the nucleophilic attack to the π -allylpalladium intermediate is the enantio-determining step, in which the chiral phosphate anion is involved in stereoinduction. Using multivariable linear regression analysis, we identified that the presence of multiple noncovalent interactions with the chiral environment of the phosphate anion are integral to enantiocontrol in the transition state. The synthetic protocol to form chiral pyrrolidines was further applied to the asymmetric construction of C - O bonds at fully-substituted carbon centers in the synthesis of chiral 2,2-disubstituted benzomorpholines.
F Dean Toste, Cheng-Che Tsai, Christopher Sandford, Tao Wu, Buyun Chen, Matthew Sigman

1747 related Products with: Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling.

100 tests 1 G 1 G 5 G 500 G 50 MG 1KG100 μg 500 ml 10 g2.5 mg5 g

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#32453734   2020/05/26 To Up

Performance of two serodiagnostic tests for loiasis in a Non-Endemic area.

Loiasis, caused by the filarial nematode Loa loa, is endemic in Central and West Africa where about 10 million people are infected. There is a scarcity of convenient, commercial diagnostics for L. loa. Microscopy requires trained personnel and has low sensitivity, while the serodiagnosis is currently not standardized. Individual case management is also important in non-endemic countries to treat migrants, expatriates and tourists. We retrospectively compared the performance of a Loa Antibody Rapid Test (RDT) and a commercial ELISA pan-filarial test on 170 patients, 65 with loiasis [8 with eyeworm, 29 with positive microfilaremia, 28 with neither microfilaremia nor history of eyeworm but eosinophilia and history of Calabar swelling (occult loiasis)], 95 with other common parasitic infections and no previous exposure to L. loa (37 with M. perstans, 1 with Brugia sp., 18 with strongyloidiasis, 20 with schistosomiasis, 5 with hookworm, 4 with Ascaris lumbricoides infection, 10 with hyper-reactive malarial splenomegaly), and 10 uninfected controls. The sensitivity of the RDT and of the ELISA were 93.8% (61/65) and 90.8% (59/65), respectively. For the RDT, most of the cross-reactions were observed in patients with M. perstans: 7/37 (18.9%), followed by 1/10 (10%) with hyper-reactive malarial splenomegaly and 1/20 (5%) with schistosomiasis. None of the 27 subjects infected with intestinal nematodes was found positive at this test. The ELISA is meant to be a pan-filarial assay, and reacted extensively with cases of M. perstans (95%), as expected, and also in 11/18 (61.1%) patients with strongyloidiasis and in 3/5 (60%) with hookworm infection. The RDT and the ELISA are both highly sensitive for the diagnosis of loiasis. The main difference lies in the extent of cross-reactivity with other parasites. Considering that the RDT is specifically meant for Loa loa infection, and its high sensitivity, this test could be a useful tool for the diagnosis of occult loiasis.
Federico Gobbi, Dora Buonfrate, Michel Boussinesq, Cedric Chesnais, Sebastien Pion, Ronaldo Silva, Lucia Moro, Paola Rodari, Francesca Tamarozzi, Marco Biamonte, Zeno Bisoffi

1628 related Products with: Performance of two serodiagnostic tests for loiasis in a Non-Endemic area.

500 tests50 ul96 tests50 ul500 tests24 tests20 ul96 tests500 tests96 tests96 tests

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#32453309   2020/05/26 To Up

The importance of the composite mechanisms with two transition states in the F + NHI S2 reaction.

The dynamics of the bimolecular nucleophilic substitution (SN2) reactions at nitrogen are less understood than those of their corresponding reactions at carbon. In this paper, we report an ab initio molecular dynamics approach to investigate the reaction mechanisms of the F- + NH2I SN2 reaction at nitrogen. We found not only the one-transition-state mechanisms, but also the composite mechanisms with two and three transition states. For the two-transition-state mechanisms, the double inversion mechanism and the proton-abstraction roundabout followed by the backside-attack reaction mechanism have been reported before; but we discovered that there is also a new, front-side attack followed by the backside-attack Walden-inversion mechanism. Furthermore, a composite mechanism with three transition states also shows up in the reactive trajectories. Our results show that, as the collision energy increases, the SN2 reactivity decreases, and the proton-abstraction reactivity increases. The two-transition-state mechanisms, especially the double-inversion mechanism, make the largest contribution to the SN2 reactivity, followed then by the one-transition-state mechanisms, with the three-transition-state mechanism contributing the least. The potential energy profiles of the reaction mechanisms are characterized at the CCSD(T)/aug-cc-pVTZ(PP) level of theory. The analysis on stationary points shows that the proton-abstraction inversion transition state is ∼12.4 kcal mol-1 lower than the Walden-inversion transition state in contrast to the corresponding reaction at carbon F- + CH3I, in which the former is ∼26.1 kcal mol-1 higher than the latter. This might explain why the composite mechanism of the double inversion mechanism contributes the most to the SN2 reactivity in the F- + NH2I reaction.
Yan Li, Yongfang Li, Dunyou Wang

1844 related Products with: The importance of the composite mechanisms with two transition states in the F + NHI S2 reaction.

100 U1

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#32452669   2020/05/26 To Up

Model Complexes Elucidate the Role of the Proximal Hydrogen-Bonding Network in Cytochrome P450s.

Cytochrome (Cyt) P450s are an important class of enzymes with numerous functions in nature. The unique reactivity of these enzymes relates to their heme active sites with an axially bound, deprotonated cysteine (a "cysteinate") ligand (chemically speaking a thiolate). The heme-thiolate active sites further contain a number of conserved hydrogen-bonds (H-bonds) to the bound cysteinate ligand, which have been proposed to tune and stabilize the Fe-S bond. In this work, we present the low-temperature preparation of five ferric heme-thiolate nitric oxide (NO) model complexes that contain one hydrogen-bond to the bound thiolate ligand. We show that the presence of a H-bond has a dramatic effect in stabilizing the thiolate ligand against direct reaction with NO. This observation reinforces the important protective role of H-bonds in Cyt P450s. We further demonstrate that H-bond strength tunes thiolate donor strength, which, in turn, controls the N-O and Fe-NO stretching frequencies and hence, bond strengths. We observe a direct correlation between the Fe-NO and N-O stretching frequencies, indicative of a thiolate σ- effect (interaction). Here, very small changes in H-bond strength lead to a surprisingly large effect on the FeNO unit. This result implies that subtle changes in the Cys-pocket of a Cyt P450 can strongly affect reactivity. Importantly, using the Fe-NO/N-O correlation established here, the thiolate donor strength in heme-thiolate enzyme active sites and model complexes can be in a straightforward way, using NO as a probe. This spectroscopic correlation provides a quantitative measure of the thiolate's "push" effect, which is important in O-activation (Compound I formation) in Cyt P450s in general.
Andrew P Hunt, Subhra Samanta, Matthew R Dent, Michael W Milbauer, Judith N Burstyn, Nicolai Lehnert

2704 related Products with: Model Complexes Elucidate the Role of the Proximal Hydrogen-Bonding Network in Cytochrome P450s.

11 kit1

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