Biomedical subjects

M Mor

Publications and source records attributed to M Mor.

42 records · Page 3Linked to original sources

PubMedDate not supplied

The 1226G (N370S) Gaucher mutation among patients with Legg-Calve-Perthes disease.

Legg-Calve-Perthes disease (LCPD) is an avascular necrosis of the femoral head with an annual incidence of 5-15/100,000. The estimated incidence of Gaucher disease, a lysosomal recessive storage disease, is 1:850, with a carrier rate of 1:17.5 for the 1226G (N370S) mutation among Ashkenazi Jews in whom there is a predilection. Since clinical and radiological findings of avascular hip necrosis due to either Gaucher disease or LCPD may be indistinguishable, misdiagnosis may occur. The purpose of this study was to evaluate the incidence of 1226G Gaucher mutation in a cohort of radiologically confirmed LCPD patients (diagnosed 1986-2000) in Israel. Enzyme assay was performed for confirmation of affected versus carrier status in patients with the 1226G mutation. In all, 78 LCPD patients, 86% males, 51% with severe bone disease, were studied. Family history was negative for Gaucher disease. Ethnic origin was 39% Ashkenazi Jewish, 6% Arab, and 55% other ethnicities. One Ashkenazi Jewish LCPD patient was homozygous for the 1226G mutation, and 4 LCPD patients were carriers: 3 Ashkenazi Jewish and 1 Arab patient. The frequency of the 1226G mutation among the LCPD patients was increased relative to historical Ashkenazi Jewish Israeli controls (P = 0.01). Since Gaucher disease may be misdiagnosed as LCPD, glucocerebrosidase enzyme testing is recommended among Ashkenazi Jewish children diagnosed with LCPD.

Clinical Enzyme Tests↗

PubMedDate not supplied

Structure-affinity relationships of indole-based melatonin analogs.

This paper reviews our progress made in characterizing structure-affinity relationships of indole-based melatonin analogs. Evidence is presented suggesting a preferred folded conformation for the amido side chain, almost orthogonal to the plane of indole. A 3D-QSAR comparative molecular field analysis (CoMFA) model, accounting for the observed differences in binding affinity within different classes of melatonergic ligands, and capable of quantitatively predicting the binding affinity of new compounds, is also reported.

Animals↗

PubMedDate not supplied

HPLC detection of thioperamide from biological samples and its determination in rat blood and brain after systemic administration.

Thioperamide is a potent and selective antagonist on histamine H3 receptors. A method for its isolation and quantitation by HPLC from rat plasma and brain samples has been developed. Using this technique, thioperamide concentrations in rat plasma and brain were measured after systemic administration, in order to evaluate its persistence in blood and its ability to cross the blood-brain barrier. We observed that, at a dose of 60 mg/Kg, thioperamide undergoes a slow elimination from plasma, with a half-life of 10 hours, and can readily cross the blood-brain barrier.

Animals↗

PubMedDate not supplied

Plasma concentration and brain penetration of the H3-receptor antagonist thioperamide in rats.

Thioperamide is a potent and selective H3-receptor antagonist, whose in vivo effects have been reported after systemic administration. Some questions have arisen about its ability to cross the blood-brain barrier, since different experimental conditions have given different results in rats, namely a low brain/blood ratio at low doses (10 mg/Kg) and a much higher one at higher doses (60 mg/Kg). In this work we demonstrate the dose-dependence of thioperamide pharmacokinetics, measuring its plasma and cerebral levels after i.p. administration of different doses to rats. Both the plasma half-life and brain penetration of thioperamide resulted as being dose-dependent: when administered to 80 g body weight Wistar rats at 10 mg/Kg i.p., the drug has a short half life (120') and a rather poor brain penetration, but increasing the dose (to 20, 40 and 60 mg/Kg) gives rise to a prolongation of its persistence in the blood (up to 600' at highest dose) and a higher brain penetration. Also, the profile of the plasma concentration curve varies from the dose of 10 to that of 20 mg/Kg, passing from a mono-exponential decrease to a more complex one characterized by an apparent distribution phase. The different distribution processes can be interpreted in the light of thioperamide protein binding and affinity for lipophilic tissues: protein binding can prevent brain penetration (but not distribution to other tissues) at lower doses, while at higher doses the free plasma fraction increases and it can allow passive distribution to lipophilic tissues such as brain tissues. A re-distribution from these tissues and plasma is probably responsible for the strong increase in half-life at high doses.

Animals↗

PubMedDate not supplied

In vitro characterization of potency, affinity and selectivity of H3-antagonists: from thioperamide to thioperamide unrelated imidazole derivatives.

This paper summarizes the findings obtained for three different series of original compounds designed as potential H3-antagonists starting from thioperamide structure. The compounds were tested in functional and binding assays to estimate their potency, affinity and selectivity for histamine H3 receptors. Among them, many non-thiourea/isothiourea derivatives acted as selective H3 competitive antagonists and, particularly, 4(5)-[2-[4(5)-cyclohexylimidazol-2-ylthio]ethyl] imidazole (dIII) proved to be the most potent H3 blocker vs (R)-alpha-methylhistamine in electrically-stimulated ileum. This imidazole derivative, devoid of thiourea dependent toxic effects, with high affinity displaced biphasically [3H]-N alpha-methylhistamine bound to rat brain H3 sites. Thus, such compound could be proposed as the prototype molecule for the development of new non-thiourea/isothiourea H3-antagonists and as experimental tool to explore the intriguing question of H3 receptor heterogeneity.

Animals↗

PubMedDate not supplied

H3-receptor antagonists: conformational analysis of thioperamide and x-ray crystal structure of the analog N-cyclohexyl-4-methylpiperidine-1-carbothioamide.

Thioperamide (N-cyclohexyl-4-[4(5)-imidazolyl]piperidine-1-carbothioamide) is a potent H3-receptor antagonist, the low conformational flexibility of which could be a favourable feature in the design of new H3-receptor antagonists using its structure as a template. Minimum-energy conformations of thioperamide were studied with the molecular mechanics approach, integrated by X-ray crystallography on an analogue, N-cyclohexyl-4-methylpiperidine-1-carbothioamide (1). Compound 1 was synthesized, and its structure has been solved by X-ray diffraction in order to verify the conformation of the piperidine-1-carbothioamide fragment, and to compare the crystallographic results with those of molecular mechanics. Conformational analysis on the free-rotating bonds of thioperamide was performed with different search methods in order to find the minimum-energy conformations and to estimate rotational barriers. For steric reasons, the rotation around the bond connecting the cyclohexane ring with the carbothioamide nitrogen is more hampered than that around the bond connecting imidazole with piperidine. The rotation around the first bond presents two symmetrical energy minima separated from a third minimum by an energy barrier of 40 KJ/mol. The spatial disposition of compound 1 in the crystal and the common part of thioperamide in one of its minimum-energy conformations are very similar. The minimum-energy conformations of thioperamide calculated by molecular mechanics are therefore reliable and they can be used for structural comparisons with other H3-receptor antagonists.

Crystallography, X-Ray↗