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Biomedical subjects

K R McIntire

Publications and source records attributed to K R McIntire.

At least 55 records · Page 3Linked to original sources

The value of serial measurement of both human chorionic gonadotropin and alpha-fetoprotein for monitoring germinal cell tumors.

Quantitative serial serum measurements of human chorionic gonadotropin (hCG) and alpha-fetoprotein (AFP) levels using sensitive double-antibody radioimmunoassays were performed in nine patients with germinal cell tumors before and during treatment. The sera of eight of the nine were found to have a hCG marker and five of the nine an AFP marker. The sera of four patients were found to have both. Serial serum levels of hCG, of AFP, or both were useful for monitoring disease activity during therapy in all nine patients. In two patients tumor masses failed to diminish during chemotherapy, but the tumor markers fell appropriately. At surgery one patient had a mature teratoma, the other a mature teratoma with a microscopic focus of an embryonal cell tumor. In one patient tumor reactivation was reflected by the emergence of only one of two previously elevated tumor markers. One patient had a rise in hCG, another a rise in both markers coincident with recurrence of tumor. Serial measurements of AFP and hCG are useful for following the response to therapy of germinal tumors, and can assist in making therapeutic decisions.

Adult↗

Effect of surgical and chemotherapeutic treatment on alpha-fetoprotein levels in patients with hepatocellular carcinoma.

Quantitative determinations of serum alpha-fetoprotein (AFP) by radioimmunoassay in 193 patients with hepatocellular carcinoma have demonstrated a wide variation in serum levels that appear to be relatively constant for each patient by the time that diagnosis is made. If there is no therapeutic intervention the serum AFP usually follows a gradual increase as the tumor progresses. A few patients have a fall in serum AFP as a preterminal event. Various forms of chemotherapy cause only minor and transient decrease in serum AFP. Surgical resection of tumor produces an immediate fall that parallels the catabolic decay rate for AFP. All AFP-positive patients treated with surgery had recurrence of their tumor with a rise in serum AFP preceeding clinical discovery. The correlation of serum AFP and effective treatment is demonstration of the usefulness of this oncofetal protein marker as an indicator of neoplastic activity for hepatocellular carcinoma and tumors with embryonal cell components and possibly for some other entodermally derived neoplasms.

Carmustine↗

Carcinogenicity of aflatoxin B1 in rhesus monkeys: two additional cases of primary liver cancer.

Three of 42 (7%) monkeys given aflatoxin B1 (AFB1) for longer than 2 years have developed primary malignant neoplasms of the liver. Liver biopsies performed at intervals during aflatoxin administration revealed that neoplasia was preceded by pathologic lesions of the liver, including toxic hepatitis, proliferation of pseudotubules, and hyperplastic nodules. Serum alpha-fetoprotein levels, monitored in one of the monkeys by radioimmunoassay, paralleled tumor growth and recurrence of the hepatocellular carcinoma. Normal serum alpha-fetoprotein levels were noted for a monkey with hemangioendothelial sarcoma. Our results implicate AFB1 as a liver carcinogen in monkeys and add additional support to the hypothesis that humans exposed to this substance may be at risk of developing liver cancer.

Aflatoxins↗

alpha-fetoprotein in noneoplastic hepatic disorders.

Serum alpha-fetoprotein levels were measured by radioimmunoassay in 473 patients with biopsy-proved noneoplastic hepatic disorders; 22% had values greater than 40 ng/ml, whereas only 1 of 350 patients with nonhepatic benign diseases had a value greater than this. Levels exceeded 40 ng/ml in more than 30% of patients with various types of hepatitis, and in 0% to 15% with inactive postnecrotic cirrhosis, primary biliary cirrhosis, biliary tract obstruction, and alcoholic liver disease. Values greater than 500 mg/ml were observed solely in viral subacute hepatic necrois. Only one patient had a level exceeding 3,000 ng/ml, the concentration at which alpha-fetoprotein is detectable by agar-gel diffusion. Of 75 patients with hepatoma, serum alpha-fetoprotein levels exceeded 40 ng/ml in 69%, and exceeded 3,000 ng/ml in 48%. These studies indicate that serum alpha-fetoprotein levels are elevated in several nonneoplastic hepatic disorders when a sensitive assay is used; this phenomenon may reflect hepatic regeneration.

Acute Disease↗

Nonhuman primate models for lymphoma, leukemia, and other neoplasms.

Herpesvirus saimiri (HVS) is an oncogenic virus for a variety of nonhuman primates. HVS does not produce overt disease upon inoculation in the natural host (squirrel monkey) but consistently induces neoplasms including lymphomas and lymphocytic leukemias in 4 other species of monkeys. Various drugs inhibit replication of HVS in vitro including cytosine arabinoside and adenine arabinoside. In addition, the lymphoma and leukemia induced in owl monkeys responds to vincristine and prednisolone, cyclophosphamide, cytosine arabinoside, and human interferon. Of the various chemical carcinogens studied, the antitumor agent procarbazine induces neoplasms in a variety of species including monkeys. Thus far this compound has induced acute myelogenous leukemia (AML), lymphoma, and hemangiosarcomas in macaques. We have induced primary liver tumors in macaques with several nitrosamines and aflatoxin B1 and these tumors produce alpha-fetoprotein (AFP) which can be assayed for both diagnosis and therapy. Thus far, therapy of hepatocellular carcinoma has been most successful with surgical resection; and the tumor mass and serum AFP have been less responsive to single agent chemotherapy. These nonhuman primate models are useful for an understanding of the cause, diagnosis, prevention, and treatment of the human disease.

Animals↗

Serum alpha-fetoprotein in patients with neoplasms of the gastrointestinal tract.

Serum alpha-fetoprotein levels were measured by a sensitive double-antibody radioimmunoassay in 580 patients with a variety of malignant and nonmalignant gastrointestinal diseases to determine the incidence of levels elevated above 40 ng/ml. Over 200 normal control subjects have all had levels below 40 ng/ml. Fifteen % of 95 patients with gastric carcinoma, 3 percent of 191 patients with colorectal carcinoma, 24 percent of 45 patients with pancreatic carcinoma, 25 percent of 8 patients with biliary tract carcinoma, and 70 percent of 73 patients with hepatocellular carcinoma had elevated serum alpha-fetoprotein. None of 14 patients with esophageal or small bowel carcinoma had elevated levels. In contrast, 1 percent of 154 patients with nonmalignant, nonhepatic gastrointestinal disease had elevations of serum alpha-fetoprotein. Alpha-Fetoprotein appears to be a potential marker for tumor activity in some patients with certain gastrointestinal cancers.

Adult↗