Island biogeography theory explains the genetic diversity of a fragmented rock ptarmigan (Lagopus muta) population

The island biogeography theory is one of the major theories in ecology, and its applicability to natural systems is well documented. The core model of the theory, the equilibrium model of island biogeography, predicts that species diversity on an island is positively related to the size of the island, but negatively related by the island's distance to the mainland. In recent years, ecologists have begun to apply this model when investigating genetic diversity, arguing that genetic and species diversity might be influenced by similar ecological processes. However, most studies have focused on oceanic islands, but knowledge on how the theory applies to islands located on the mainland (e.g., mountain islands, forest islands) is scarce. In this study, we examined how the size and degree of isolation of mountain islands would affect the genetic diversity of an alpine bird, the rock ptarmigan (Lagopus muta). Within our study area, we defined the largest contiguous mountain area as the mainland, while smaller mountains surrounding the mainland were defined as islands. We found that the observed heterozygosity (H o) was significantly higher, and the inbreeding coefficient (F is) significantly lower, on the mainland compared to islands. There was a positive significant relationship between the unbiased expected heterozygosity (H n.b.) and island size (log km2), but a negative significant relationship between H o and the cost distance to the mainland. Our results are consistent with the equilibrium model of island biogeography and show that the model is well suited for investigating genetic diversity among islands, but also on islands located on the mainland.

Phase-I human clinical-trial of onconase(r) (p-30 protein) administered intravenously on a weekly schedule in cancer-patients with solid tumors

ONCONASE(R) (ONC), previously known as P-30 Protein, is a novel amphibian protein isolated from Rana pipiens eggs/early embryos (1) which demonstrates cytostatic and cytotoxic activity against several human tumor cell lines in vitro, as well as anti-tumor activity in vivo. Animal toxicology studies in rats and dogs revealed dose-dependent weight loss, some skeletal muscle and myocardial degenerative changes, a decrease in albumin and bilirubin levels in rats, and a dose-related elevation of serum transaminases and alkaline phosphatase in both species. A human weekly schedule Phase I study of intravenous bolus ONC was initiated, with dose levels ranging from 60 mug/m2 (anticipated human dose) to 960 mug/m2. Five patients were treated per dose level, without dose escalations within the same patients. Dose levels were doubled in new groups of patients with a variety of relapsing and resistant tumors. A correlation was noted between the dose level and the number of doses (cumulative effect), and the toxicities observed. The dose limiting toxicity was renal as manifested by proteinuria with edema, +/- azotemia and fatigue. Other side effects included flushing, myalgias, transient dizziness, and decreased appetite. Two patients, one at 480 mug/m2 and another at 960 mug/m2 levels, developed reversible hypotensive reactions preceded by flushing. The maximum tolerated dose (MTD) appears to be 960 mug/m2. Incidental findings included some objective responses in non-small cell lung, esophageal, and colorectal carcinomas. It has been concluded that ONCONASE was well tolerated by the majority of patients, demonstrated a consistent and reversible clinical toxicity patterns, did not induce most of the toxicities (such as, e.g., myelosuppression and alopecia) associated with most of the chemotherapeutic agents and, in view of its demonstrated objective clinical activity observed in patients harboring resistant solid tumors, the Phase II clinical trials have been initiated and are currently ongoing.

Relationship between response rate and median survival in patients with advanced nonsmall cell lung-cancer - comparison of onconase(r) with other anticancer agents

The role of systemic cytotoxic therapy for the treatment of advanced non-small cell lung cancer (NSCLC) remains controversial. The response rate (RR) and the median survival time (MST) are the two most frequently used parameters for the assessment of efficacy of the anti-cancer therapies. The relationship between the previously reported RRs and MSTs from published chemotherapy trials in patients with advanced NSCLC was examined using linear regression analysis. The MST of the thirty patients with advanced NSCLC treated with ONCONASE (ONC) as a single agent was 7.7 months which compared favorably with the MSTs of patients treated with a variety of chemotherapeutic regimens either as single agents or combinations, as well as placebo and supportive care only. Moreover, the toxicity profile of ONC compared favorably to the profiles of other chemotherapy regimens. ONC had a favorable impact on the overall MST, including patients with stage IV disease, patients with poor performance status, and patients previously treated with radiotherapy and chemotherapy. The MST of 5 patients who had a stabilization of previously progressive disease was 9.3 months. Based on its positive impact on the MST, ONC appears to have a single agent activity in patients with advanced NSCLC, and it should be further investigated, particularly in combination with synergistic drugs, in concurrently controlled and prospectively randomized clinical trials. The duration and the quality of survival should be considered as the most meaningful parameters in assessing clinical efficacy of anti-cancer agents.

Studies on the mechanism of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU)-induced hepatotoxicity. II. Biochemical and morphological characterization of the injury and its prevention by phenobarbital

The present study characterizes the biochemical, morphological, and histological sites of CCNU-induced hepatotoxicity and investigates the effect of modifiers of drug metabolism on this toxicity. A single oral dose (100 mg/kg) of CCNU caused four- and ninefold increases in serum GOT and GPT respectively 48 h after administration in rats. A 25-fold rise in serum bilirubin, a total loss of bile flow, and a decrease in BSP clearance were also observed. Cytochrome P-450 content and EM-N-demethylase activity were significantly decreased to 88% and 66% of control values respectively. A histopathological time course study of CCNU-induced injury showed a progression of acute inflammation, edema, and fibrin deposition in portal areas over 24 h with necrosis and sloughing of bile duct epithelium at 24 and 36 h. Treatment of rats with PB (40 mg/kg/day for 4 days, i.p.) 24 h prior to CCNU administration protected against CCNU-induced hepatotoxicity. Thus, the levels of serum GOT, GPT, and bilirubin were only 2.5 and 4 times higher than in untreated or PB-treated controls. Histopathological examination also showed reduced severity of bile duct lesions in PB-pretreated animals. In rats receiving both PB and CCNU, bile flow was restored and BSP clearance was increased compared to the CCNU-treated rats. The mixed-function oxidase activity in PB + CCNU-treated rats was not significantly different from that in PB-treated controls. It is concluded that pretreatment of rats with PB can markedly suppress the hepatotoxic manifestations, including histopathological changes, the rise in serum bilirubin, and the cholestasis observed in CCNU-treated rats.

Adriamycin and cyclophosphamide versus hydroxyurea in advanced prostatic cancer. A randomized Southwest Oncology Group study

Over a 24-month period, the Southwest Oncology Group (SWOG) conducted a randomized prospective chemotherapeutic trial in 158 patients with advanced prostatic cancer. Patients were initially randomized to receive either a combination of Adriamycin and cyclophosphamide (AC) or a single agent, hydroxyurea (H), and then crossed over to the other treatment on failure. Of the 137 evaluable patients, 43 (31%) had classically measurable metastatic disease in the lymph nodes, skin, chest, or liver. Focusing their efforts on this subset of patients with measurable disease, the authors of this report found the combination AC to have a superior response rate to the single agent, hydroxyurea. Objective response to AC was seen in 6 of 19 (32%) and in only one of 24 (4%) patients randomized to hydroxyurea (P = 0.06, Fisher's exact test). However, in the larger group of 137 evaluable patients, a survival advantage was not seen for those individuals treated with AC. Failure to demonstrate a survival advantage for an objectively superior drug combination would suggest the need for more active phase II agents in this disease.

Phase II evaluation of amsacrine (m-AMSA) in solid tumors, myeloma, and lymphoma: a University of Arizona and Southwest Oncology Group Study

A phase II trial was conducted to determine the clinical activity of amsacrine (m-AMSA) in patients with heavily pretreated solid tumors, myeloma, and lymphoma at the University of Arizona Cancer Center. Additionally, m-AMSA was evaluated at other Southwest Oncology Group institutions in breast cancer, myeloma, melanoma, and oat cell cancer of the lung. At a dose of 120 mg/m2 given iv every 28 days, 12 partial responses were observed in 221 patients evaluable for response. Some antitumor activity was observed in breast cancer (four responses of 65 patients), non-Hodgkin's lymphoma (three of nine), Hodgkin's disease (two of five), and sarcoma (two of 15). A partial response was also documented in one of two patients with cervical cancer. Among the 135 patients treated at the University of Arizona who were extensively evaluated for toxic effects, only myelosuppression and anemia were seen in a significant number of patients. At this dose and schedule, 29% of patients developed leukopenia of less than 3000 cells/mm3, 16% developed a thrombocytopenia of less than 100,000 cells/mm3, and 29% had an acute fall in hemoglobin of greater than or equal to 2 g/100 ml. In addition, two patients suffered grand mal seizures which were not clearly drug-related. These results suggest that further study of m-AMSA in lymphoma, sarcoma, and cervical cancer is warranted.

Tissue distribution and macromolecular interactions of 14[C-ring] melphalan in the rat

The kinetics of uptake and elimination, covalent binding, and macromolecular interactions of 14[C-ring] melphalan was studied after a single oral dose (20 mg/kg, 0.1 mCi/kg) in normal rats. Peak radioactivity level in tissues was observed at 2-4 h after administration. Uptake of label in most tissues was rapid, with a t1/2 of less than 1 h. Elimination was biphasic. Tissues of the gastrointestinal tract showed the most rapid rates of elimination, with t1/2 beta of 13, 24, 18, and 19 h for stomach, duodenum, and small and large intestines, respectively. Bone marrow also showed a fast rate of elimination of radioactivity, with a t1/2 beta of 30 h. Tissues with the slowest rates of elimination were skin, eye, spleen, pancreas, and lung, with t1/2 beta of 333, 241, 149, 122, and 109 h, respectively. Covalent binding studies showed that melphalan, or its metabolites, bound irreversibly to all tissue macromolecular fractions. The percentage of covalently bound radioactivity increased with time in all tissues except kidney and eye, reaching up to 70%-80% of the total radioactivity remaining at 72 h. Elimination of covalently bound radioactivity was slower in the DNA fractions of the tissues of the gastrointestinal tract and heart compared with the elimination rate from lipid, protein, or RNA fractions. Slow elimination rates of 14[C-ring] melphalan equivalents from the protein fraction were observed in the skin, eye, and brain. Accumulation, rather than elimination, of radioactivity in this fraction was most prominent in the pancreas. In the bone marrow accumulation of radioactivity was observed in the lipid fraction.

Combination chemotherapy (CMFVP) versus L-phenylalanine mustard (L-PAM) for operable breast cancer with positive axillary nodes: a Southwest Oncology Group Study

The Southwest Oncology Group in a prospective randomized study compared one year of adjuvant combination chemotherapy with continuous CMFVP to two years of intermittent L-PAM in women with operable breast cancer with histologically positive axillary lymph nodes. In fully evaluable patients with a 42-month median and 30-month minimum follow-up, treatment failures have occurred in 26% of 145 receiving CMFVP and 47% of 167 women given L-PAM (P = 0.002). Disease-free survival times were significantly longer with CMFVP than with L-PAM in the following subgroups: premenopausal women (P = 0.002), postmenopausal women (P = 0.002), women with 1-3 involved axillary nodes (P = 0.003), and women with four or more involved axillary nodes (P = 0.002). CMFVP was effective in pre- and postmenopausal women. There is a significant difference in survival in favor of CMFVP compared to L-PAM (P = 0.005). The life table estimates of survival at 42 months are 86% for women on the CMFVP treatment arm and 73% for women on the L-PAM treatment arm. There was no correlation between the interval from mastectomy to onset of chemotherapy (between one and six weeks) and recurrence rates. Acute toxicity with both treatment arms was moderate and reversible. These results show that continuous CMFVP is superior to intermittent L-PAM in decreasing recurrences and increasing survival in both pre- and postmenopausal women with operable breast cancer with histologically involved axillary nodes.

Macromolecular interactions of [14C-ring]melphalan in blood

The pharmacokinetics and macromolecular interactions of [14C-ring]melphalan (L-PAM) in blood were studied in rats following a single oral dose (20 mg/kg, 0.1 mCi/kg). Radioactivity levels were monitored in blood over a period of 72 hr. The highest levels of radioactivity were observed at 2 hr. The decline of radioactivity from the blood was biphasic with T1/2 alpha = 7 hr and T1/2 beta = 75 hr. The radioactive species in plasma corresponded to unchanged L-PAM and its two known hydrolytic products 4,2-hydroxyethyl 2-chloroethylamino-L-phenylalanine (L-MOH) and 4-[bis(2-hydroxyethyl)amino]-L-phenylalanine (L-DOH). In addition, four other major, previously unknown, metabolites of L-PAM were detected in plasma. At 72 hr, most of the radioactivity was bound to macromolecular components, 26% to plasma macromolecules and 62% in red blood cells. Covalent binding to blood cells was mainly to membrane proteins. Binding to hemoglobin and other soluble components of the red cells was also observed, with a 5000-fold greater affinity for membranes. These studies suggest extensive interaction of melphalan, or its metabolites, with membrane and soluble proteins of red blood cells.

Phase I-II trial of methyl-GAG: a Southwest Oncology Group Pilot Study

One hundred and nine patients with advanced malignancy, refractory to conventional therapy, were treated with a weekly schedule of methyl-GAG. Ninety-one patients (83%) were less than fully ambulatory. Sixty-five patients were fully evaluable for response. There were two complete and nine partial responses. An additional nine patients had objective tumor regressions and were classified as improved. The median duration of response was 5 months. Toxic effects were primarily mucositis (17 patients) and nausea and vomiting (14 patients). Sixty-seven patients had no manifestations of drug toxicity. Responses observed in a wide variety of solid tumors warrant further clinical trials.

5 FU infusion with mitomycin-C vs. 5 FU infusion with methyl-CCNU in the treatment of advanced upper gastrointestinal cancer: a Southwest Oncology Group Study

A randomized trial was conducted by the Southwest Oncology Group (SWOG) in advanced carcinoma of the stomach and pancreas. Patients were assigned to receive monthly 5-fluorouracil 96-hour continuous infusions with either bolus mitomycin-C or oral methyl-CCNU. Mitomycin-C and methyl-CCNU were administered every eight weeks. The 5 FU-mitomycin combination produced a 14% and 22% response rate in disseminated stomach and pancreatic carcinoma, respectively. The combination of infusion 5 FU and methyl-CCNU achieved responses in 9% and 5% of stomach and pancreatic tumors, respectively. There was no significant difference in survival between limbs for either tumor. Median survival in gastric carcinoma on the 5 FU-mitomycin regimen was 25 weeks vs. 18 weeks on the 5 FU-METHYL-CCNU arm. In pancreatic carcinoma median survival on the mitomycin limb was 19 weeks as compared to 17 weeks on the methyl-CCNU program. Leukopenia was greater for the first course on the mitomycin limb. Regression analysis demonstrated that performance status was the most important pretreatment characteristic for predicting survival in both tumors. Neither 5 FU infusion combination appears to significantly alter the dismal prognosis of advanced upper gastrointestinal neoplasms.

Adriamycin in combination for the treatment of breast cancer: a Southwest Oncology Group study

Patients with advanced breast cancer who had not previously received chemotherapy were treated on a three-arm prospective study: adriamycin day 1 plus 5-FU on day 1 and 8 (AF), adriamycin day 1, plus 5-FU day 1 and 8, and cyclophosphamide day 1 (AFC), and adriamycin day 1 plus 5-FU day 1 and 8, cyclophosphamide day 1 and methotrexate day 1 (AFCM). These courses were repeated every 21 days. The response rate was 44/105 (42%) AF, 44/103 (43%) AFC and 52/105 (49%) AFCM. The length of response was 22, 33 and 35 weeks, respectively, for AF, AFC and AFCM (P = 0.21). The median survival, 64 weeks, was equal in all three limbs. The major toxicity was leukopenia. Twenty-eight percent developed a WBC of less than 2,000/microliter, which resulted in seven deaths (2.2%).

Phase II study of 5-azacytidine in solid tumors

A phase II study utilizing 5-azacytidine in the treatment of patients with solid tumors was carried out by the Southwest Oncology Group (SWOG-7208). Of 214 patients entered in the study 191 were eligible and 167 were evaluable. While initially they received 225 mg/m2 iv on Days 1--5 every 3 weeks because of toxicity the dose was subsequently reduced to 175mg/m2 and later to 150 mg/m2. Five partial regressions, 2.6% of the eligible patients and 3% of the evaluable patients, lasting from 28 to 77 days were observed. Sixteen patients 8.4% of the eligible patients and 9.6% of the evaluable patients, had no significant change in their disease for 39--255 days. The major toxicities were myelosuppressive and gastrointestinal with 13 deaths attributable to drug toxicity: 11 due to sepsis and two due to cerebral hemorrhage. 5-Azacytidine induced few favorable responses; those that did occur usually were of poor quality and short duration and were associated with significant toxicity.