Dose-response effects of free fatty acids on amino acid metabolism and ureagenesis.

AIM: Free fatty acids (FFAs) are important fuels and have vital protein-sparing effects, particularly during conditions of metabolic stress and fasting. However, it is uncertain whether these beneficial effects are evident throughout the physiological range or only occur at very high FFA concentrations. It is also unclear whether secondary alterations in hormone levels and ketogenesis play a role. We therefore aimed at describing dose-response relationships between amino acid metabolism and circulating FFA concentrations at clamped hormone levels. METHODS: Eight healthy men were studied on four occasions (6 h basal, 2 h glucose clamp). Endogenous lipolysis was blocked with acipimox and Intralipid was infused at varying rates (0, 3, 6 or 12 microL kg(-1) min(-1)) to obtain four different levels of circulating FFAs. Endogenous growth hormone, insulin and glucagon secretion was blocked by somatostatin (300 microg h(-1)) and replaced exogenously. 15N-phenylalanine, 2H4-tyrosine and 13C-urea were infused continuously to assess protein turnover and ureagenesis. RESULTS: We obtained four distinct levels of FFA concentrations ranging from 0.03 to 2.1 mmol L(-1) and 3-hydroxybutyrate concentrations from 10 to 360 micromol L(-1). Whole-body phenylalanine turnover and phenylalanine-to-tyrosine degradation decreased with increasing FFA levels as did insulin-stimulated forearm fluxes of phenylalanine. Phenylalanine, tyrosine and urea concentrations also decreased progressively, whereas urea turnover was unperturbed. CONCLUSION: Circulating FFAs decrease amino acid concentrations and inhibit whole-body phenylalanine fluxes and phenylalanine-to-tyrosine conversion. Our data cover FFA concentrations from 0 to 2 mmol L(-1) and indicate that FFAs exert their protein conserving effects in the upper physiological range (>1.5 mmol L(-1)).

Dose-response effects of free fatty acids on glucose and lipid metabolism during somatostatin blockade of growth hormone and insulin in humans.

CONTEXT: GH and other stress hormones stimulate lipolysis, which may result in free fatty acid (FFA)-mediated insulin resistance. However, there are also indications that FFAs in the very low physiological range have the same effect. OBJECTIVE: The objective of the study was to address systematically the dose-response relations between FFAs and insulin sensitivity. DESIGN: We therefore examined eight healthy men for 8 h (6 h basal and 2 h glucose clamp) on four occasions. INTERVENTION: Intralipid was infused at varying rates (0, 3, 6, 12 microl.kg(-1).min(-1)); lipolysis was blocked by acipimox; and endogenous GH, insulin, and glucagon secretion was blocked by somatostatin and subsequently replaced at fixed rates. RESULTS: This resulted in four different FFA levels between 50 and 2000 micromol/liter, with comparable levels of insulin and counterregulatory hormones. Both in the basal state and during insulin stimulation, we saw progressively decreased glucose disposal, nonoxidative glucose disposal, and forearm muscle glucose uptake at FFA levels above 500 micromol/liter. Apart from forearm glucose uptake, the very same parameters were decreased at low FFA levels (approximately 50 micromol/liter). FFA rate of disposal was linearly related to the level of FFAs, whereas lipid oxidation reached a maximum at FFA levels approximately 1000 micromol/liter. CONCLUSION: In the presence of comparable levels of all major metabolic hormones, insulin sensitivity peaks at physiological levels of FFAs with a gradual decrease at elevated as well as suppressed FFA concentrations. These data constitute comprehensive dose-response curves for FFAs in the full physiological range from close to zero to above 2000 micromol/liter.

Prevalence and prognostic significance of infection with TT virus in patients infected with human immunodeficiency virus.

No clear association between human disease and TT virus (TTV) has been documented. A possible pathogenic role of TTV was investigated in patients infected with human immunodeficiency virus (HIV). TTV serum concentrations were estimated in 185 HIV-infected patients by dilution polymerase chain reaction. Of these, 149 (76%) were TTV-positive, compared with 18 (7%) of 252 Danish blood donors (P<. 001). Of the HIV-infected patients who were TTV-positive, 72 (51%) had high TTV viremia (>/=5 times the highest concentration observed among blood donors, i.e., >/=3.5x105 TTV/mL of serum). High TTV viremia was associated with decreased survival (P<.001; relative hazard [RH], 2.0). There was a correlation between lower CD4+ T cell counts and higher TTV titers (P<.01). In a Cox regression model, CD4+ T cell count (P<.001), age (P<.001), HIV viral load (P<.001), beta2 microglobulin (P<.02), and high TTV viremia (P<.01; RH, 1.9) were independent predictors of survival. TTV is suspected to be an opportunistic pathogen with an independent influence on HIV progression.

Bulk culture levels of specific cytotoxic T-cell activity against HIV-1 proteins are not associated with risk of death.

The ability of cytotoxic T lymphocytes (CTL) to control and influence the outcome of human immunodeficiency virus (HIV) infection is not fully understood. The association between HIV-CTL activity and disease progression was evaluated prospectively in 36 HIV-1-infected individuals with a median follow-up of 3.0 years. HIV-CTL activity was measured in a 4 h Cr* release assay using autologous target cells expressing HIV-1 BRU isolate gene products (gp-120, gag, pol, nef) and a bulk culture of autologous effector cells. The CD4 count was measured at enrolment and plasma HIV RNA was measured retrospectively. The present study failed to support the hypothesis that HIV-CTL activity, as measured using the present method, is important in reducing the risk of death in HIV-infected individuals. However, using other approaches and methods could possibly yield other conclusions, and further prospective studies are needed to examine the relationship between CTL and disease progression.

[Parvovirus B19 infection--a meningococcus-like sepsis]. / Parvovirus B19-infektion--et meningokoksepsislignende billede.

Two otherwise healthy adults with fever and haemorrhagic exanthema are described. In both, primary human parvovirus infection was diagnosed. The clinical picture of fever and haemorrhagic exanthema should always arouse suspicion of serious disease such as meningococcal infection. If the patient is unaffected, however, primary human parvovirus infection should be borne in mind.

[Chronic lymphatic leukemia. Peroral cladribine as primary treatment]. / Kronisk lymfatisk leukaemi. Peroral cladribin som primoer behandling.

Ten patients with newly diagnosed B-chronic lymphocytic leukaemia were treated with cladribin orally for five days every four weeks with a median of four series. This is the first reported clinical study where a purine analogue is administered orally. The tumour reducing effect was fast. Eight out of 10 patients responded with a partial or clinical complete remission. Two of these were in molecular biological complete remission. With an observation time of 22 months we have seen no serious side effects so far. A randomized study (including a long term follow up) between chlorambucil, fludarabin and cladribin is needed to clarify the future role of cladribin in B-CLL treatment.

Salvage therapy with fludarabine in patients with progressive B-chronic lymphocytic leukemia.

Thirty patients with B-chronic lymphocytic leukemia, aged 45-82 years, were treated with fludarabine. CLL was diagnosed 8-120 months earlier. The patients had been exposed to a median of 3 different regimens before treatment with fludarabine, and all had progressive disease when they entered the study. Among the 30 patients, 1 had a metastatic carcinoma and 7 patients with WHO performance status 3 died before the second cycle of fludarabine treatment could be given. The remaining 22 patients were considered eligible for response evaluation. The response rate was 32% with 1 complete response and 6 partial responses. However, seven patients achieved stable disease and 8 progressed. The median survival for responders was 24 months and for non-responders 9 months. Response to treatment was correlated with low tumor burden and performance status. In a total of 94 treatment courses, 17 febrile episodes were registered in 10 patients. We conclude that treatment with fludarabine can be useful in patients with progressive and refractory disease.

Dose-response relationship of epirubicin in the treatment of postmenopausal patients with metastatic breast cancer: a randomized study of epirubicin at four different dose levels performed by the Danish Breast Cancer Cooperative Group.

PURPOSE: To test for possible correlations between dose of single-drug epirubicin and efficacy/toxicity in postmenopausal women with metastatic breast cancer. The study also included analysis of a correlation between pharmacokinetic and pharmacodynamic parameters. PATIENTS AND METHODS: Two hundred eighty-seven women were randomized to receive either 40, 60, 90, or 135 mg/m2 of epirubicin intravenously (IV) every 3 weeks. Treatment consisted of first-line cytotoxic therapy for metastatic disease. In patients with early progressive disease after either 40 or 60 mg/m2, dose escalation to 135 mg/m2 was performed. A full pharmacokinetic analysis was performed in 78 patients. RESULTS: Among 263 eligible patients, an increase in response rate and time to progression was found with an increase in dose from 40 to 90 mg/m2, while no increase in efficacy was found from 90 to 135 mg/m2. Multivariate analysis, using the Cox proportional hazards model with time to progression as the end point, confirmed that epirubicin dose more than 60 mg/m2 was an independent prognostic covariate. Furthermore, a significant association was established between randomized dose and both hematologic and nonhematologic toxicity. No association between pharmacokinetic parameters and efficacy parameters was demonstrated. On the other hand, a significant correlation between pharmacokinetic parameters and both hematologic and nonhematologic toxicity was found. CONCLUSION: An increase in dose of epirubicin from 40 to 90 mg/m2 is accompanied by increased efficacy. Further increases in dose do not yield increased efficacy. A positive correlation between epirubicin dose and toxicity, as well as a correlation between pharmacokinetic parameters and toxicity, was also established.

The cardioprotector ADR-529 and high-dose epirubicin given in combination with cyclophosphamide, 5-fluorouracil, and tamoxifen: a phase I study in metastatic breast cancer.

The purpose of this study was to determine the maximal tolerable dose (MTD) of epirubicin and ADR-529 given in combination with cyclophosphamide, 5-fluorouracil, and tamoxifen. A total of 64 breast cancer patients with locally advanced disease or a first metastatic event were included. Using fixed doses of cyclophosphamide, 5-fluorouracil, and tamoxifen, cohorts of ten patients were treated with escalating doses of epirubicin and ADR-529. With the use of protocol criteria specifying evaluation after the first course, the MTD was not reached. Dose reductions carried out due to hematologic toxicity during the first four courses made it impossible to escalate doses of epirubicin beyond 80 mg/m2 given together with ADR-529 600 mg/m2. The vascular toxicity of ADR-529 necessitated central venous access in a number of patients. For phase III evaluation of ADR-529 given together with cyclophosphamide, epirubicin, 5-fluorouracil, and tamoxifen (CEF/TAM) we recommend using epirubicin/ADR-529 at 60/600 mg/m2. Together with evaluation of the cardioprotective properties of ADR-529, we recommend evaluating the impact of ADR-529 on the efficacy of cytotoxic therapy and investigating further the toxicity of ADR-529.

The pharmacokinetics of high-dose epirubicin and of the cardioprotector ADR-529 given together with cyclophosphamide, 5-fluorouracil, and tamoxifen in metastatic breast-cancer patients.

A high-pressure liquid chromatographic method for determination of the bisdioxopiperazine derivative ADR-529 (ICRF-187), a compound proven effective in protection against anthracycline-induced cardiotoxicity, has been developed. The limit of quantitation was 5 ng/ml using a narrow-bore 5-microns silica column and UV detection. The method was used for determination of pharmacokinetic profiles of ADR-529 after a 3-weekly i.v. administration of different doses of ADR-529 (600-1000 mg/m2) together with different doses of epirubicin (E, 60-100 mg/m2), fixed-dose cyclophosphamide (C, 600 mg/m2), fixed-dose 5-fluorouracil (F, 600 mg/m2), and daily administration of tamoxifen (T, 30 mg; CEF-T) in the treatment of patients with metastatic breast cancer. Pharmacokinetic parameters for epirubicin were also determined. The aim of the study was to determine (1) whether the pharmacokinetics of ADR-529 as part of a combination with CEF-T changes with increasing doses of ADR-529 and increasing doses of epirubicin and (2) whether the pharmacokinetics of epirubicin in the same combinations is altered with the administration of increasing doses of ADR-529. A total of 82 patients were included. A crossover study including 16 of the patients showed no significant difference in epirubicin pharmacokinetic parameters when epirubicin was given with or without concomitant administration of ADR-529. Apart from minor changes in the distributional half-lives, the pharmacokinetic parameters of epirubicin were not altered with increasing doses of ADR-529, nor were the pharmacokinetic parameters of ADR-529 itself. Escalating doses of epirubicin did not significantly alter the pharmacokinetic parameters of ADR-529 with the exception of a 30% increase in the terminal half-life and a decrease in total body clearance when the epirubicin dose was raised from 60 to 100 mg/m2. We conclude that concomitant administration of ADR-529 does not alter the distribution and elimination of epirubicin in doses suitable for preventing the anthracycline-induced cardiotoxicity.

Phase I study of tauromustine administered in a weekly schedule.

Tauromustine was administered orally in weekly doses with interindividual dose escalation to patients with disseminated malignant melanoma. The dose in the first cohort of 6 patients was 20 mg/m2/week. The dose escalation was 5 mg/m2/week. The limit of tolerance was 55 mg/m2/week. 99 patients completed at least 8 weeks of treatment and eight dose levels were evaluated for toxicity. Reversible thrombocytopenia, and to a lesser degree leukopenia, were dose limiting. From a starting dose of 40 mg/m2/week, the long-term tolerated dose was 35 mg/m2/week, thus achieving a considerable increase of dose intensity without a significant increase of toxicity by employing this weekly schedule of tauromustine.

Acute monocytic or myelomonocytic leukemia with balanced chromosome translocations to band 11q23 after therapy with 4-epi-doxorubicin and cisplatin or cyclophosphamide for breast cancer.

PURPOSE: To report five cases of acute monocytic or myelomonocytic leukemia after chemotherapy with 4-epidoxorubicin for breast cancer and to evaluate the risk of leukemia after the use of this drug. PATIENTS AND METHODS: One hundred fifty-seven patients with advanced breast cancer were randomized to either 4-epi-doxorubicin plus cisplatin or 4-epi-doxorubicin alone. An additional 203 patients were treated prospectively with 4-epi-doxorubicin alone. All were observed closely for leukemic complications. RESULTS: Three patients from the randomized study developed leukemia; all were in the subgroup of 74 patients who received 4-epi-doxorubicin plus cisplatin, whereas no leukemia was observed among the remaining 83 patients in the randomized study or among the additional 203 patients who were treated prospectively with 4-epi-doxorubicin alone (P = .023, log-rank test). In the subgroup of 74 patients who were treated with 4-epi-doxorubicin plus cisplatin, the cumulative risk of leukemia was 16.0% +/- 9.9% (mean +/- SE) 33 months after the start of therapy; the relative risk was 668 (95% confidence interval [Cl], 138 to 1,953). Two other cases of acute monocytic and myelomonocytic leukemia were observed after 4-epi-doxorubicin plus alkylating agents were administered for breast cancer. Three of five cases of leukemia presented balanced translocations to chromosome band 11q23 and two, loss of a whole chromosome no. 7 or its long arm. CONCLUSIONS: 4-epi-doxorubicin is leukemogenic, and the leukemias are often acute monocytic or myelomonocytic with balanced chromosome translocations to band 11q23, such as in the leukemias after therapy with the epipodophyllotoxins. Furthermore, our results suggest a synergistic effect in leukemogenesis between 4-epi-doxorubicin targeting DNA-topoisomerase II and directly genotoxic drugs such as cisplatin or alkylating agents.

[Malignant melanoma of the skin in Denmark--epidemiology, diagnosis and treatment]. / Melanoma malignum cutis i Danmark--epidemiologi, diagnostik og behandling.

About 700 new cases of malignant melanoma of the skin are registered annually in Denmark. The incidence is increasing rapidly and the number of new cases increases by more than 5% per annum. The most important phenotypical risk factors are the number of acquired pigmented naevi and exposure to sunlight is the most important risk factor in the external environment so that severe sunburn in children and intermittent intense exposure to sunlight increase the risk of melanoma. The thickness of the tumour at the time of the diagnosis is the most important prognostic factor. The prognosis deteriorates with increasing thickness. Treatment is primarily surgical. In cases of inoperable local melanoma and regional recurrences, irradiation may be administered. Chemotherapy and/or immunotherapy are of experimental character. In the light of the rapidly increasing incidence, it is important that knowledge of risk factors for development of the disease and the clinical characteristics of early melanoma is spread to not only the medical profession but also to the general public.

Multiple-dose pharmacokinetics of epirubicin at four different dose levels: studies in patients with metastatic breast cancer.

Pharmacokinetic analysis of epirubicin and its metabolites epirubicinol and 7-deoxy-13-dihydro-epirubicinol aglycone during the first and the fourth courses of treatment was performed in 78 patients with metastatic breast cancer. The patients were treated every 3 weeks with epirubicin given as 10-min i.v. infusions at four different dose levels: 40, 60, 90 and 135 mg/m2. In most cases (76 of 78 cases), plasma concentration-time curves fitted to a three-compartmental pharmacokinetic model. The terminal half-life of epirubicin was independent of dose and duration of treatment. Large interindividual differences were demonstrated (mean t1/2 gamma, 21.6 +/- 7.9 h; range, 10.6-69 h; n = 110). In two subjects, extremely long half-lives and high serum bilirubin concentrations indicated impaired liver function. No correlation was found between the half-life and levels of liver alanine aminotransferase (ALAT) or serum creatinine. The metabolite epirubicinol appeared quickly after epirubicin administration and its half-lives were shorter than that of the parent compound (mean t1/2 gamma, 18.1 +/- 4.8 h; range, 8.2-38.4 h; n = 105). Formation of the aglycone metabolite was delayed and the half-life of this metabolite was shorter than that of epirubicin (mean t1/2 gamma, 13 +/- 4.6 h; range, 2.7-29 h; n = 104). The AUC of epirubicin and the total AUC (drug and metabolites) were linearly proportional to the dose, with the former value constituting two-thirds of the latter. A correlation was found between AUC and the plasma concentration of epirubicin at two time points (2 and 24 h after administration). The proposed model was AUC = 9.44 x c2 + 62.5 x c24 + 157.7 (r = 0.953).

A randomized study of epirubicin at four different dose levels in advanced breast cancer. Feasibility of myelotoxicity prediction through single blood-sample measurement.

Detailed pharmacokinetic analysis and subsequent evaluation of myelotoxicity were performed in 55 patients who had been randomized to 4 different doses of epirubicin (40, 60, 90 or 135 mg/m2 given i.v. every 3 weeks). A significantly positive correlation was demonstrated between the AUC and the myelotoxicity of epirubicin. A similar correlation was observed when the metabolite epirubicinol was also considered. The decrease in leucocyte count as expressed by the logarithmic ratio between nadir WBC and initial WBC was linearly correlated with the AUC of either epirubicin alone (r = -0.55, P less than 0.001) or epirubicin and epirubicinol together (r = -0.63, P less than 0.001). As a relationship between the concentration of epirubicin in a single plasma sample taken at 6 h following i.v. administration and the AUC of the drug has been established, a log-linear relationship between the expected decrease in leucocytes and the concentration at 6 h after administration could be calculated. The proposed model is expressed as the equation: log WBCnadir = log WBCinitial -0.0073 x c6 (ng/ml)-0.14.

Phase II study of tauromustine in disseminated malignant melanoma.

Forty-seven patients with metastatic malignant melanoma took part in a phase II trial of tauromustine (TCNU), a new chlorethylnitrosourea based on the endogenous amino acid taurine. TCNU was given orally at a dosage of 130 mg/m2 every fifth week. No patient had previously received cytotoxic therapy. Among 37 evaluable patients, 26 patients experienced progressive disease including seven patients with early death, five showed no change, and six partial responses, yielding an objective response rate of 16%. Responses were limited to subcutaneous, lymph node, bone and lung metastases. Median time to progression was 26 weeks for responders. The treatment schedule was well tolerated with a median dose of 88% of the predicted dose given during all cycles. Dose-limiting toxicity was thrombocytopenia. It appears that TCNU is active in disseminated malignant melanoma with a response rate similar to other nitrosoureas.

An unusual case of multiple malignancy in an adult.

An adult female is described who, during a clinical course of 25 years, presented malignant tumors of the rectum, breast, uterus and colon. Cytostatics were never administered. Lymphocyte subsets, a variety of lymphocyte and mononuclear cell stimulation assays with mitogens and antigens, DNA repair tests and activity of natural killer cells were normal. Serum leukocytic interleukin-1 activity was slightly elevated. Sister chromatid exchange frequency in peripheral lymphocytes was below the normal range. An explanation for the development of 4 primary malignant neoplasms was not found.

Correlation of growth morphology and clonability with malignancy of WEHI-7 T-cell lymphoma sublines.

This study examined the development of subclones of different proliferative capacity and malignancy in the WEHI-7 tumor. The mouse T-cell lymphoma WEHI-7 can be cloned in agar with a cloning efficiency of 40 to 50%. On the basis of growth morphology, two types of colonies were distinguished. Most colonies were compact, but a few, no more than 5%, were diffuse. Sublines of the two colony types were established. The cloning efficiency in agar was 40 to 50% for the compact and 15 to 25% for the diffuse sublines. The recloning efficiency did not change for compact colonies. In contrast, the cloning efficiency of diffuse colonies decreased with repeated reclonings. The mice died within 24 to 34 days of i.v. injection of 10(4) WEHI-7 cells. The same number of cells of the individual sublines administered to mice resulted in improved survival. Injection of compact subline cells resulted in death in 24 to 48 days, while diffuse subline cells resulted in death in 30 to 75 days. The sublines were indistinguishable by light and electron microscopy. Both subline types were negative for terminal deoxynucleotidyl transferase and positive for Thy 1.2. Most cells from the two types of sublines were Lyt-1 and Lyt-2 positive. The doubling time was 10 hr for compact and 14 hr for diffuse sublines. Colony morphology was conserved after passage in vivo and after more than 10 transfers in vitro in liquid and agar media. In conclusion, the different growth morphology in vitro distinguished the subclones of different malignancy in the WEHI-7 tumor cell line.