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Biomedical subjects

P Iyer

Publications and source records attributed to P Iyer.

31 records · Page 2Linked to original sources
PubMed1991

Role of biotransformation in the in vitro preimplantation embryotoxicity of naphthalene.

The in vitro developmental toxicity of the bicyclic aromatic hydrocarbon naphthalene was characterized with a preimplantation mouse embryo culture system. Day 3 ICR mouse blastocysts were co-cultured with naphthalene for 1 h either alone or in media supplemented with an Aroclor-induced rat S-9 preparation and cofactors. Toxin-treated blastocysts were subsequently cultured in NCTC 109 media with 10% fetal bovine serum for 72 h to observe the developmental effects of exposure. Developmental parameters observed included viability, hatching, culture dish attachment and trophoblastic outgrowth with the presence of a distinct inner cell mass. At media concentrations up to 0.78 mM, naphthalene alone exhibited negligible toxic effects in culture; however naphthalene co-cultured with Aroclor-induced rat hepatic S-9 fractions exhibited concentration-dependent embryolethality with an approximate LC50 of 0.18 mM in media. Naphthalene also induced concentration-dependent embryotoxicity at all observed parameters in S-9-supplemented media at concentrations ranging from 0.20 to 0.78 mM. These findings document the role of biotransformation in naphthalene's embryotoxicity to early mouse blastocysts and implicate naphthalene as a potentially embryotoxic and abortifacient component of polycyclic aromatic hydrocarbon mixtures.

Animals↗
PubMed1986

Good tolerance to high-dose hepatic arterial infusion therapy.

A pilot study was designed to evaluate the efficacy of high-dose FUDR administered through the hepatic artery for the treatment of cancer involving the liver. Three dose schedules were used beginning with a dose of 0.5 mg FUDR/kg/day for 2 weeks followed by normal saline infusion for 2 weeks (schedule A). Elevation of serum bilirubin was the sole indication to deescalate to schedule B (0.3 mg FUDR/kg/day for two weeks followed by saline infusion for 4 weeks). Tolerance to this schedule escalated the patient to schedule C (0.5 mg FUDR/kg/day for 2 weeks followed by normal saline infusion for 4 weeks). Eighteen patients were treated, sixteen with metastatic colon cancer, one with metastatic leiomyosarcoma, and one with hepatoma. The patient with hepatoma developed progressive disease after one cycle of therapy. Of the 17 patients with metastatic cancer only 5 patients failed therapy yielding a 70% response rate. High-dose FUDR was well tolerated with only six patients requiring deescalation to schedule B. Elevation of alkaline phosphatase and glutamic oxaloacetic transaminase was universal. Two patients developed peptic ulceration. Sclerosing cholangitis was not observed. We conclude that high-dose FUDR administered through the hepatic artery is as safe as conventional dose infusion therapy but probably not more effective. The safety of high-dose FUDR infusion therapy suggests that sclerosing cholangitis is association with hepatic arterial infusion therapy is not related to the FUDR dose.

Drug Administration Schedule↗
PubMed1983

Chemotherapy of squamous cell cancer of the head and neck.

Forty patients with advanced squamous cell cancer of the head and neck were treated with methotrexate, cisplatin, and bleomycin. Major regression of disease occurred in 69%; 30% of patients achieved complete remission. Fifteen patients received chemotherapy as the initial treatment, followed by either radiotherapy or surgery or both. Subsequent therapy was not prejudiced by this approach. The results demonstrate the marked sensitivity of these tumors to these three agents, and the need for further assessment of their use in optimal patient care.

Adolescent↗
PubMed1980

Vasculitis and ischaemic optic neuropathy associated with rheumatoid arthritis.

Fundus lesions are said not to be found in direct relationship to rheumatoid arthritis. A vasculitis or retinopathy if present is said to be secondary to concomitant hypertension or due to some connective tissue disease other than rheumatoid arthritis. The case is presented of a 64-year-old female with sero-positive rheumatoid arthritis. During a period of exacerbation of her arthritis she developed anterior ischaemic optic neuropathy (A.I.O.N.) resulting in blindness of one eye, followed two weeks later by a temporary occlusive episode in a cilioretinal arteriole in the other eye. The patient was normotensive and had neither clinical nor immunological evidence of other connective tissue disease. The patient died two months later from cardiac arrhythmia. The autopsy findings confirming posterior ciliary arteritis as the cause of the A.I.O.N. are presented. The subject of rheumatoid vasculitis in relation to the eye is reviewed and immunological mechanisms and investigations discussed.

Aged↗