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Biomedical subjects

V K Iyer

Publications and source records attributed to V K Iyer.

25 records · Page 2Linked to original sources
PubMed1986

In vitro inhibition of estrogen sulfoconjugation by some 2- and 4-substituted estra-1,3,5(10)-trien-17 beta-ols1a.

Hormone-responsive rat and human mammary tumor, unlike normal epithelium, actively sulfoconjugates estrogens. The title compounds (9-11) were synthesized in search of specific inhibitors of estrogen sulfotransferase as a possible means of developing effective chemotherapeutic agents for treatment of hormone-dependent human mammary cancer. 4-Nitroestrone 3-triflate (7a) was converted to the corresponding estradiol derivative (8a) in 93% yield by reduction with NaBH4 under phase-transfer conditions. Catalytic reduction (10% Pd/C) of the latter gave 4-aminoestra-1,3,5(10)-trien-17 beta-ol (9a) in 77% yield. These same reactions were applied consecutively to 4-nitroestrone 3-nonaflate (7b) to give 9a in 56% overall yield. The amino steroid (9a) was converted to 4-fluoroestra-1,3,5(10)-trien-17 beta-ol (10a) via a Balz-Schiemann reaction, in 17% overall yield. Successive NaBH4 and (10% Pd/C) catalytic reductions of 4-fluoroestrone 3-O-(1-phenyl-1H-tetrazol-5-yl) ether (2b) provided a less satisfactory route to 10a. MCPBA oxidation of 9a gave 4-nitroestra-1,3,5(10)-trien-17 beta-ol (11a) in 56% yield. The same series of reactions were applied to 2-nitroestrone 3-triflate (7c) to give 2-amino- (9b), 2-fluoro- (10b), and 2-nitro- (11b) estra-1,3,5(10)-trien-17-ols in comparable yields. Substitution in the A ring results in improved inhibition of porcine endometrial sulfotransferase sulfoconjugation of estradiol relative to estra-1,3,5(10)-trien-17 beta-ol (4a). Moreover, electronegative substitution at C-4 of 4a is more effective than at C-2. In particular, the Ki (2.43 +/- 0.16 microM) of 11a is sixfold smaller than that of the unsubstituted steroid (4a).

Animals↗
PubMedDate not supplied

Fine needle aspiration cytology of dermatopathic lymphadenitis.

OBJECTIVE: To delineate and describe the cytomorphologic features of dermatopathic lymphadenitis on fine needle aspirated material. STUDY DESIGN: Thirteen cases of previously diagnosed dermatopathic lymphadenitis (DLN) and 10 cases of reactive lymphadenitis (RLN) (5 each of sinus histiocytosis and follicular hyperplasia) were reexamined by two independent observers. The cytologic features were semiquantitated (0-3+). Histology was available in two cases. RESULTS: A variable amount of melanin pigment was seen in all 13 cases of DLN and in only 3 cases of RLN. DLN had large histiocytic collections with blood vessels at the center (12/13). The histiocytic cells had an elongated nucleus (13/13) with nuclear grooves (13/13) and pseudonucleoli (11/13). Many of these nuclei had a convoluted and crumpled appearance (11/13). On immunocytochemistry these cells were S-100 positive (six cases) and CD68 negative (one case). In contrast, in RLN with sinus histiocytosis, the histiocytes were polygonal and had rounded nuclei. Spindle-shaped histiocytes were rare, while pseudonucleoli and nuclear grooves were absent. Sinus histiocytes were CD68 positive and S-100 negative on histologic sections. Tingible body macrophages were rare (2/13) in DLN and prominent (8/10) in RLN. Mitoses were seen in DLN (6/13) and RLN (9/10). CONCLUSION: The morphologic features found to be helpful in the diagnosis of DLN on fine needle aspiration cytology are melanin-laden macrophages with variable pigment; large, histiocytic clusters with blood vessels at the center; characteristic histiocytes, with elongated vesicular nuclei, nuclear grooves, crumpled and convoluted nuclei and pseudonucleoli; and absence of or very few tingible body macrophages. Positivity on immunostaining for S-100 and negativity for CD68 aid in the diagnosis.

Biopsy, Needle↗
PubMedDate not supplied

Non-syndromic paucity of interlobular bile ducts.

A 3 1/2-month-old male infant presented with cholestatic jaundice. Peroperative cholangiogram showed a gall bladder and small but patent extrahepatic bile ducts. Liver histology showed paucity of interlobular bile ducts. The child is being treated medically for his symptoms.

Bile Ducts, Extrahepatic↗