PubMed Health⌕ Search

Biomedical subjects

P Hosain

Publications and source records attributed to P Hosain.

15 recordsLinked to original sources
PubMed1992

Synthesis, characterization and biodistribution of a new hexadentate aminethiol ligand labeled with Tc-99m.

A new hexadentate aminethiol ligand (TACNS) derived from triazacyclononane was synthesized and characterized for the development of technetium radiopharmaceuticals. The ligand formed a neutral, lipophilic and stable complex with [99mTc]pertechnetate in the presence of tin(II)tartarate as a reducing agent. The biodistribution of [99mTc]TACNS indicates slight uptake in brain (0.23% ID/organ at 5 min) with a washout at 30 min to 0.14% ID/organ. A small uptake in heart (0.48% ID at 5 min) was also observed. The characterization of [99mTc]TACNS complex using single crystal x-ray analysis and mass spectroscopy has shown that an Sn-N3S3 complex was formed in which tin is oxidized from Sn(II) to Sn(IV). Pertechnetate was incorporated into the complex as counter anion. The nature of the species formed with Tc-99 and "no-carrier-added" [99mTc]pertechnetate is different as confirmed by ratio TLC. From these results, it is demonstrated that sometimes it may be difficult to predict the structure of new technetium radiopharmaceuticals, especially when stannous ion is used as a reducing agent. Moreover, the nature of the chemical species may not be the same at millimolar and at nanomolar levels.

Animals↗
PubMed1984

Comparison of biodistribution of 3H, 32P and 99mTc labeled Gpp(NH)p in tumor bearing hamsters.

Biodistribution and tumor uptake studies were carried out with intravenously injected tracer doses of Gpp(NH)p labeled with 3H, 32P or 99mTc . Syrian golden hamsters with cheek pouch carcinomas, induced by repeated topical applications of DMBA, were used as a tumor model. The biodistributions of these three radionuclides were different, indicating significant molecular cleavage of this nucleotide analog. It was also apparent that this compound labeled with 99mTc may not be useful for tumor imaging due to low tumor-to-blood specific activity ratio. The cheek pouch carcinoma tumor model may be valuable for the evaluation of tumor localizing radiopharmaceuticals.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

Bone accumulation of the Tc-99m complex of carbamyl phosphate and its analogs.

Carbamyl phosphate, an organic molecule containing a single phosphate group, has been used in the therapy of sickle-cell disease. Carbamyl phosphate bound Tc-99m and achieved bone uptake in mice, rabbits, and a human volunteer. By examination of the structural formula, a working hypothesis was developed that predicted that the Tc-99m complexes of the analogous compounds acetyl phosphate, propionyl phosphate, and butyryl phosphate, each carrying single phosphate and carbonyl groups, would also show bone specificity. This was confirmed experimentally. Phosphonoacetic acid is a structural analog of these compounds. The structural analysis also predicted that aminomethylphosphonic acid and phosphoenolpyruvate would not have as avid bone affinity, and this was also confirmed. These compounds represent a new class of bone-seeking agents that have the common properties of a lone phosphate and a carbonyl function. Such agents may permit the synthesis of additional analogs in an effort to obtain optimal affinity in the Tc-99m complexes.

Adult↗
PubMed1978

Synthesis, radiotechnetium labelling, and comparison of biologic behavior of longer-chain analogs of methylene diphosphonate.

Polymethylene diphosphonic acids of different chain lengths ( n = 2, 3, and 10) were synthesized and labeled with technetium-99m. Their biologic behavior was compared with that of Tc-99m-labeled methylene diphosphonate (MDP) in experimental animals. With n = 2 (ethylene diphosphonic acid), the compound resembled MDP in bone affinity. The longer-chain analogs had lower bone affinity.

Animals↗
PubMed1976

Technetium-99m labelled imidodiphosphate: an improved bone-scanning radiopharmaceutical.

Technetium-99m labelled imidodiphosphate was prepared in the presence of stannous ions. It was evaluated as a bone-scanning agent in animals and patients. Comparative tissue distribution studies in mice showed a relatively higher uptake of radioactivity in bone when 99Tcm -labelled pyrophosphate and diphosphonate. Accumulation of radioactivity in soft tissues, especially kidneys, was less with this radiopharmaceutical. Results in patients were most satisfactory in delineating skeletal bone and identifying bone lesions with relatively small tracer doses of the radiopharmaceutical.

Animals↗