Hyperhomocysteinemia-related serum metabolome alterations not normalized by short-term folic acid treatment.

INTRODUCTION: Hyperhomocysteinemia (HHCys) is an independent risk factor for various diseases such as cardiovascular diseases, Alzheimer's, and cancers. Folate deficiency is one of the significant reasons for HHCys. However, it is not known whether folate deficiency with HHCys is associated with any serum metabolites. OBJECTIVES: Our objective was to identify the metabolic alterations in people having folate deficiency with HHCys and check whether a short-term folic acid therapy could reverse those metabolic changes. METHODS: The study enrolled 34 participants aged between 18 and 40 years having folate deficiency (< 4.6 ng/mL) with HHCys (> 15 µmol/L) and 21 normal healthy individuals. A short-term intervention of oral folic acid (5 mg/day) was done in the HHCys group for 30 days. Untargeted metabolomics analysis of serum was performed in all study subjects before and after the folic acid treatment. Different univariate methods and the multivariable-adjusted linear regression models were employed to determine an association between homocysteine level and metabolite profile. RESULTS: Metabolomics analysis data showed that many metabolites involved in the biochemical pathways of lipid metabolisms such as polyunsaturated fatty acids, glycerolipids, and phospholipids were downregulated in the HHCys group. Short-term oral folic acid therapy significantly reduced their serum homocysteine level. However, the metabolic pathway alterations observed in folate-deficient HHCys-condition were unaltered even after the folic acid treatment. CONCLUSIONS: Our study revealed that people who have a folic acid deficiency with HHCys have an altered metabolite profile related to lipid metabolism, which cannot be reversed by short-term folic acid therapy.

Technetium-99m DTPA dimethyl ester: a renal function imaging agent. Comparative studies in animals with technetium-99m mercaptoacetyl triglycine and 131I-ortho-iodohippurate.

The dimethyl ester of diethylene triamine penta-acetic acid (DMDTPA) (I) can be easily and efficiently labelled with 99mTc. This method can be readily adapted for kit formulations to produce a highly stable and very pure chelate, as shown by paper electrophoresis and reverse-phase high performance liquid chromatography experiments. In mice, this chelate was excreted unchanged in the urine, and the amount of renal excretion was much higher than that of 99mTc-DTPA and comparable with that of 99mTc-mercaptoacetyl triglycine (99mTc-MAG(3)) at two different time points. The renal excretion of co-injected 131I-ortho-iodohippurate (131I-OIH), however, was significantly greater than that of the 99mTc chelates. The renal clearance values of 99mTc-DMDTPA and 99mTc-MAG(3) were also similar and exceeded the corresponding value for 99mTc-DTPA, but were only half that of the 131I-OIH value in the rat. The renograms for 99mTc-DMDTPA and 99mTc-MAG(3) showed overall similarity in a dog model. The diethyl ester (III) and monoethyl ester (II) of DTPA, after labelling with 99mTc, produced the same chelate, as shown by analytical results and biological data, indicating that one of the ester groups in the DTPA diester is dealkylated during the chelation procedure. To confirm this, two more ligands, diethylene triamine 1,4,7,7-tetra-acetic acid (IV) and diethylene triamine 1,4,7-triacetic acid (V), were synthesized, resembling DTPA monoalkyl ester (II) and dialkyl ester (I, III), respectively, in the arrangement of the donor atoms. Ligand IV but not ligand V, on 99mTc chelation, can generate the specific pharmacophore for renal tubular transport that is also present in the ester chelates 99mTc-I, 99mTc-II and 99mTc-III, as shown by their decreased renal excretion in mice pretreated with a renal tubular transport inhibitor such as probenecid.

Purification and stabilization of 99mTc-d,l-HMPAO: role of organic extractants.

99mTc-d,l-HMPAO, an important SPECT agent for imaging cerebral perfusion, suffers from the disadvantage of an inherent instability and its shelf life has been reported to be 30 min. The latter is a harsh constraint and not compatible with Centralized Radiopharmacy procedures. During the attempts to improve upon the stability of 99mTc-d,l-HMPAO, preservation of product as an organic extract into suitable solvents like diethylether, ethylacetate, methylethylketone, chloroform was tried out. Chloroform extraction (yield: >90%) resulted in a product having stability not less than 5 hours. Gentle drying of the chloroform extract and reconstitution in normal saline resulted in quantitative recovery of 99mTc-d,l-HMPAO with acceptable radiochemical purity (>90%). This finding is thus of much significance, especially in the context of centralized large hospital radiopharmacy setting, by rendering convenience and flexibility in scheduling patients.

Lipid metabolic changes in experimentally induced leptospiral infection with serovars australis, canicola and icterohaemorrhagiae.

Changes in lipid fractions were evaluated in young guinea pigs when infected with 1 ml of 7 day old live cultures of leptospira interrogans serovars australis, canicola and icterohaemorrhagiae. Statistically significant elevation in triglycerides, very low density lipoprotein and phospholipid and a significant reduction in high density lipoprotein (HDL) in all the groups was observed. Cholesterol and low density lipoprotein showed ascending trend in icterohaemorrhagiae group, whereas they were normal in other groups. The results suggest that increase in triglycerides, phospholipid and decrease in HDL in a suspected case of leptospirosis may be considered as markers.

Preparation of 99mTc-ethylene dicysteine (99mTc-EC) by transchelation using 99mTc-glucoheptonate (99mTc-GHA) and its evaluation for renal function studies.

The complexation of ethylene dicysteine (EC) with 99mTc needs to be carried out at pH 12 to achieve a high radiochemical yield. However, the preparation of the kit at high pH poses difficulties and requires very stringent preparation conditions, as stannous tin, one of the main ingredients in the kit, is unstable at high pH. Hence, an alternative method, involving the transchelation preparation of 99mTc-EC using 99mTc-glucoheptonate (99mTc-GHA) prepared at pH 6.5, was attempted, prompted by the reported success of the preparation of 99mTc-sestamibi (99mTc-MIBI) by this method. The preparation of 99mTc-EC by this method first involved the formation of 99mTc-GHA by the addition of sodium pertechnetate-99mTc to the Sn-GHA kit vial at pH 6.5. 99mTc-EC was formed by the addition of reconstituted EC solution at pH approximately 12 to the preformed 99mTc-GHA. The reaction was allowed to proceed both at room temperature and on a boiling water bath. The pH of the final product was adjusted to pH approximately 7 with 0.5 M phosphate buffer at pH 4-5, without affecting the quality of the product. The urinary excretion of 99mTc-EC prepared by transchelation, tested in mice, was similar to that of directly prepared 99mTc-EC, indicating that the final product prepared by the two methods was the same. The clinical evaluation of the product formulated by the new procedure showed satisfactory findings, comparable with the reports in the literature.

Zinc counteracts experimentally-induced cirrhotic changes in rats.

In the present study, cirrhosis was induced in rats by administration of carbon tetra chloride for 8 weeks. In these animals ZnSo4 (equivalent to 100 and 200 micrograms of zinc) was administered orally and liver function tests and plasma zinc (Zn) estimations were carried out after 2 and 4 week intervals. The results revealed that Zn supplement counteracts cirrhotic changes in liver.