Integrating animal health and foodborne disease surveillance.

The control of foodborne diseases from an animal source has become an important part of public health policy. Since the agents that cause these diseases originate in animals, Veterinary Services, as well as Public Health Services, must be involved in their control. Control programmes should be established either through cooperation between the two Services or by the consolidation of all those involved into a single food control agency. Surveillance is an important part of these control programmes. The following questions must be addressed when planning an effective surveillance programme. What is the relative incidence, morbidity, mortality and economic cost of the foodborne disease in humans? Is the animal population the exclusive or a significant source of the human foodborne infection? What kind of surveillance is needed to identify the disease-causing agent in the animal population? Are we interested in identifying all cases of a disease in order to eradicate it or is our aim to reduce its incidence in the animal population? Do we have the ability to control the disease in the animal population? What disease detection tests are available? What are the sensitivity, specificity and cost of these diagnostic tests? Finally, does the country, region or agency involved have the legal, financial and educational resources to carry out this surveillance and follow it up with appropriate action? After these questions have been resolved,the veterinary and public health sectors must jointly decide if surveillance and control are feasible. If so, they can then begin to develop an appropriate programme.

Recent trends in the epidemiology of non-typhoidal Salmonella in Israel, 1999-2009.

The aim of the present study was to assess the recent trends in the epidemiology of non-typhoid Salmonella in Israel using a sentinel laboratory-based surveillance network. Between 1999 and 2009, 8758 Salmonella stool isolates were reported by five sentinel laboratories. There was a significant decrease in the incidence rate of Salmonella isolates from 70·5/100,000 in 1999 to 21·6/100,000 in 2005 followed by a slight increase to 30·3/100,000 in 2009. Of all Salmonella, 64·3% were isolated from children in the 0-4 years age group. Up to 2008, S. Enteritidis was the most prevalent serotype and in 2009 S. Infantis emerged as the most common Salmonella serotype. The decrease in the incidence of S. Enteritidis and S. Typhimurium and increase in S. Infantis among humans were associated with a similar trend among breeding flocks, which followed significant preventive interventions conducted against S. Enteritidis and S. Typhimurium infections in poultry. Tight surveillance and education of food handlers and consumers should be enhanced to reduce the foodborne transmission of Salmonella in Israel.

The bioethics and utility of selling kidneys for renal transplantation.

In the 53 years since kidney transplantation was first performed, this procedure has evolved from a highly speculative biomedical endeavor to a medically viable and often standard course of therapy. Long-term survival is markedly improved among patients who receive a kidney compared with patients who remain on the waiting list for such an organ. As outcomes have improved and more clinical indications have emerged, the number of people awaiting transplantation has grown significantly. In stark contrast to the robust expansion of the waiting list, the number of available deceased donors has remained relatively constant over the last several years. The current mechanism for procuring kidneys relies on voluntary donations by the general public, with the primary motivation being altruism. However, in light of the ever-increasing waiting list, it is the researchers' belief that the current system needs to be revised if supply is ever going to meet demand. In response to this critical organ shortage, different programs have been developed in an attempt to increase organ donation. At present, however, no solution to the problem has emerged. This report begins by outlining the scope of the problem and current legislation governing the procurement of transplantable organs/tissues in the United States. It continues with an overview of different proposals to increase supply. It concludes by exploring some of the controversy surrounding the proposal to increase donation using financial incentives. Though the following discussion certainly has implications for other transplantable organs, this report focuses on kidney transplantation because the waiting list for kidneys is by far the longest of all waiting lists for solid organs; and, as kidney transplant carries the smallest risk to living donors, it is the least ethically problematic.

Inter-trial neuronal activity in inferior temporal cortex: a putative vehicle to generate long-term visual associations.

When monkeys perform a delayed match-to-sample task, some neurons in the anterior inferotemporal cortex show sustained activity following the presentation of specific visual stimuli, typically only those that are shown repeatedly. When sample stimuli are shown in a fixed temporal order, the few images that evoke delay activity in a given neuron are often neighboring stimuli in the sequence, suggesting that this delay activity may be the neural correlate of associative long-term memory. Here we report that stimulus-selective sustained activity is also evident following the presentation of the test stimulus in the same task. We use a neural network model to demonstrate that persistent stimulus-selective activity across the intertrial interval can lead to similar mnemonic representations (distributions of delay activity across the neural population) for neighboring visual stimuli. Thus, inferotemporal cortex may contain neural machinery for generating long-term stimulus-stimulus associations.

Risk factors for Newcastle disease in broiler farms in Israel.

Following a large outbreak of Newcastle disease (ND) in Israel, a cross-sectional study was conducted in the broilers sector. The aim of the study was to find geographical and farm related risk factors for ND. Information was available on 96% of the broiler farms in Israel. Of these, farms diagnosed with ND in the years 2010-2012 were compared with the other farms. Risk factors for ND were analyzed, using Generalized Estimating Equation models. Six variables were found to be associated with the risk for ND outbreak: a distance of less than 300m from another farm (OR=1.77, 95% CI 1.07-2.93), a distance of less than 6000m from a national border (OR=2.00, 95% CI 1.22-3.30), farm location in the Ha'amakim district (OR=2.46, 95% CI 1.32-4.61), village type: a Moshav (village) vs. Kibbutz (Cooperative village) (OR=1.96, 95% CI 1.04-3.70), and carcass disposal in an uncovered bin (OR=1.96, 95% CI 1.18-3.26). A distance of less than 800m from an inter-city road was found to be a protective factor (OR=0.60, 95% CI 0.37-0.98). The results of this study provide information that may be used to improve surveillance and control of ND.

Optimal long-term antithrombotic treatment of patients with stable coronary artery disease and atrial fibrillation: "OLTAT registry".

BACKGROUND: The optimal long-term antithrombotic treatment of patients with stable coronary artery disease (CAD) and atrial fibrillation (AF) is a challenge in daily practice. We sought to determine the prevalence of hemorrhagic complications and ischaemic events depending on antithrombotic strategy in patients with stable CAD and AF. METHODS: The primary outcome was major adverse cardiac and cerebrovascular events (MACCE) defined as a composite of cardiovascular mortality, myocardial infarction and ischaemic stroke. The subsequent risks of MACCE and clinically significant bleedings requiring hospitalisation (major safety outcome) were analyzed in a propensity score-matched analysis by adjusted Cox regression models. RESULTS: Six hundred and six patients with high thrombotic and bleeding risks (mean age 73.4 ±â€¯9.8 years, 25.2% female, CHA2DS2-VASc score:4.7 ±â€¯1.5, and HAS-BLED score:3.1 ±â€¯1.0) were included, and 127 propensity-matched pairs were analyzed. At inclusion, 172 patients (28.4%) were on oral anticoagulation (OAC) alone (75.6% on VKA and 24.4% on DOAC) and 434 patients (71.6%) on OAC + single antiplatelet therapy (SAPT) (71.9% on VKA and 28.1% on DOAC). At 5-year follow-up, MACCE rate did not significantly differ in both groups (30.9% in OAC + SAPT vs. 26.8% in OAC alone; adjusted HR 1.1 [0.8-1.5], p = 0.58), but clinically significant bleedings (28.3% vs. 18.5%; adjusted HR 1.8 [1.2-2.8], p = 0.005) and total deaths (29.5% vs. 20.8%; adjusted HR 1.4 [95% CI 1.0-2.2], p = 0.049) were higher in patients with OAC + SAPT than in patients with OAC alone. CONCLUSIONS: In patients with stable CAD and AF, the addition of antiplatelet therapy to VKA or DOAC therapy was independently associated with a higher risk of bleeding and overall mortality, without significant reduction in cardiac and cerebral ischaemic events.

Slower B16 melanoma growth but greater pulmonary colonization in calorie-restricted mice.

Recently, it has been demonstrated that the immune function is preserved longer and spontaneous tumors occur less frequently in calorie-restricted (but not malnourished) mice. In the present report the effect of similar dietary manipulation on tumor growth, metastases, and survival was studied. C57BL/6 mice were fed regular laboratory diets, either restricted in calories or not restricted, and later inoculated with B16 melanoma sc, iv, or ip. Local tumor growth was found to be slower; however, survival after ip injection was no different, and the number of pulmonary metastatic colonies after iv injection was greater for the underfed mice. In this weakly immunogenic tumor model, factors in addition to immunity influenced tumor growth and were altered by calorie restriction.

Germline p53 gene mutations in subsets of glioma patients.

BACKGROUND: Heritable germline mutations of the p53 gene have been described in patients with Li-Fraumeni syndrome, occasionally in nonfamilial malignancies such as multifocal osteosarcoma, in a small subgroup of young patients with two or more primary malignancies, and in patients with sporadic breast carcinoma. We recently reported that multifocal gliomas are frequently associated with other primary malignancies, and we hypothesized that genetic alterations may account for this phenomenon. PURPOSE: We examined the frequency of germline p53 gene mutations in patients with glioma and either multifocality of lesions, history of an additional primary (different) malignancy, or a family history of cancer. METHODS: Lymphocytes from 51 glioma patients were analyzed for germline p53 gene mutations using RNA-polymerase chain reaction analysis, single-strand conformation polymorphism, and gene sequencing techniques. RESULTS: Germline p53 gene mutations were detected in six of 19 patients with multifocal glioma, including two with family history of cancer, one with another primary malignancy, and two with all three risk factors; one of four patients with unifocal glioma, another primary malignancy, and a family history of cancer; and two of 15 patients with unifocal glioma and a family history of cancer but no second malignancies. No mutations were detected in the patient with unifocal glioma and another malignancy or in the 12 control patients with unifocal glioma and no second malignancies or family history of cancer. Patients having mutations were younger than other patients in the same group. CONCLUSIONS: Germline p53 mutations are frequent in patients with multifocal glioma, glioma and another primary malignancy, and glioma associated with a family history of cancer, particularly if these factors are combined. IMPLICATIONS: Relatives at high risk can be identified for genetic counseling, early cancer detection, and possible enrollment in chemoprevention trials.

Regulation of the proliferation of the established human monoblast cell line, U937, at the single cell level.

U937 cells, an established monoblast or early monocyte cell line, were assessed as a model in vitro for the regulation of cell growth at the single cell level. Colony formation by 500 U937 cells, preinduced to a state of responsiveness to lactoferrin (LF) by incubation with human gamma interferon was suppressed by LF. LF-suppressed colony formation was restored by partially purified growth activity derived from U937 cells. The release of growth factor(s) into conditioned medium required concentrations of greater than 500 U937 cells/ml and this release was dependent on the length of time that the cells conditioned the culture medium. This release was suppressed by LF. U937 cells were induced to a state of responsiveness to LF by incubation with human gamma interferon, washed, and plated as a single cell per well. Individual cells formed colonies with a cloning efficiency of approximately 50% which equalled the cloning efficiency detected when 500 U937 cells/ml were plated, suggesting that U937 colony forming cells might contain endogenous growth activity. Detection of these endogenous growth activities required the use of LF. The cloning efficiency of individually isolated U937 cells was suppressed by approximately 50% with LF, similar to the LF suppression of colony formation when 500 cells/ml were plated. That the LF-suppressed U937 colony forming cells required growth activity was suggested as the cloning efficiency of LF-suppressed individually isolated U937 colony forming cells was restored by partially purified U937 growth activity. Partially purified U937 growth activity did not stimulate, enhance, or inhibit colony formation by normal human bone marrow granulocyte-macrophage progenitors. U937 cells can thus serve as a useful model for the study of growth regulation at the level of a single cell.

Levels of phospholipid metabolites in breast cancer cells treated with antimitotic drugs: a 31P-magnetic resonance spectroscopy study.

Magnetic resonance spectroscopy (MRS) methods have provided valuable information on cancer cell metabolism. In this study, we characterized the 31P-MR spectra of breast cancer cell lines exhibiting differences in hormonal response, estrogen receptors (positive/negative), and metastatic potential. A correlation was made between the cytotoxic effect of antimitotic drugs and changes in cell metabolism pattern. Because most anticancer drugs are more effective on proliferating cells, our study attempted to elucidate the metabolic profile and specific metabolic changes associated with the effect of anticancer drugs on proliferating breast cancer cell lines. Accordingly, for the 31P-MRS experiments, cells were embedded in Matrigel to preserve their proliferation profile and ability to absorb drugs. The MRS studies of untreated cells indicated that the levels of phosphodiesters and uridine diphosphosugar metabolites were significantly higher in estrogen receptor-positive and low metastatic potential cell lines. 31P-MRS observations revealed a correlation between the mode of action of anticancer drugs and the observed changes in cell metabolic profiles. When cells were treated with antimicrotubule drugs (paclitaxel, vincristine, colchicine, nocodazole), but not with methotrexate and doxorubicin, a profound elevation of intracellular glycerophosphorylcholine (GPC) was recorded that was not associated with changes in phospholipid composition of cell membrane. Remarkably, the rate of elevation of intracellular GPC was much faster in cell population synchronized at G2-M compared with the unsynchronized cells. The steady-state level of GPC for paclitaxel-treated cells was reached after approximately 4 h for synchronized cells and after approximately 24 h (approximate duration of one cell cycle) for the unsynchronized ones. These observations may indicate a correlation between microtubule status and cellular phospholipid metabolism. This study demonstrates that 31P-MRS may have diagnostic value for treatment decisions of breast cancer and reveals new aspects of the mechanism of action of antimicrotubule drugs.

Localization of the beta chain of human chorionic gonadotropin on human tumor cells and placental cells.

With the use of peroxidase-labeled antibody to the beta chain of human chorionic gonadotropin, sections of ten human malignant tumors were found to react with this antibody. It is postulated that both selective host immunosuppression by tumors and selective maternal immunosuppression by fetal tissues may be mediated by human chorionic gonadotropin.

4-demethoxydaunorubicin (idarubicin) in combination with 1-beta-D-arabinofuranosylcytosine in the treatment of relapsed or refractory acute leukemia.

We conducted a Phase I-II trial of 4-demethoxydaunorubicin (idarubicin, IDR) in combination with 1-beta-D-arabinofuranosylcytosine (ara-C) in 51 patients with relapsed or refractory acute nonlymphocytic leukemia, acute lymphocytic leukemia, or chronic myelogenous leukemia in blast crisis. Only 1 of 12 patients treated at the first dose level (idarubicin, 10 mg/m2/day for 3 days and ara-C, 25 mg/m2 i.v. bolus followed by 200 mg/m2 continuous infusion daily for 5 days) achieved aplasia and complete remission. The dose of idarubicin was subsequently increased to 10 mg/m2/day for 4 days with the ara-C dose held constant. Complete remission incidence for this dose schedule was: 7 of 31 patients with acute nonlymphocytic leukemia, 0 of 5 patients with acute lymphocytic leukemia, 0 of 1 patient with chronic myelogenous leukemia in blast crisis, and 1 of 2 patients with biphenotypic leukemia. Nonhematological toxicity included nausea, vomiting, mucositis, and abnormal liver function tests. Detailed pharmacological studies were performed to determine whether ara-C altered IDR metabolism or that of its main metabolite, 13-hydroxyidarubicinol or IDR clearance. A high degree of variability among patients was apparent and no consistent effect could be demonstrated. In summary, 9 of 37 patients (24%) with relapsed or refractory ANLL, including 1 patient with biphenotypic leukemia, achieved remission. We conclude that idarubicin in combination with ara-C is an active combination in patients with relapsed or refractory leukemia.

Phase I and clinical pharmacology studies of intravenous and oral administration of 4-demethoxydaunorubicin in patients with advanced cancer.

4-Demethoxydaunorubicin (4-DMDR), an anthracycline analogue available in i.v. and p.o. form, has shown significant antitumor activity in murine tumor models while producing less cardiac toxicity than doxorubicin at equimyelotoxic doses. Phase I and clinical pharmacology studies of the i.v. and p.o. preparation were performed. With i.v. 4-DMDR, consistent myelosuppression was observed at a dose of 15 mg/sq m at a median Day 15; mild nausea and vomiting were observed in 9% of all treatment courses. In patients given p.o. 4-DMDR, myelosuppression occurred at median Day 14 in 10 of 12 patients given 50 mg/sq m. Nausea and vomiting occurred in 25% of all treatment courses, and dividing the dose over 3 days did not decrease the incidence. Alopecia occurred in 13% of evaluable patients treated with the i.v. preparation and 30% of evaluable patients treated p.o. No stomatitis was observed with either preparation, and no patient developed clinical signs of congestive heart failure. Pharmacokinetic studies were performed with both preparations and revealed prolonged plasma levels of the 13-hydroxy metabolite 4-DMDR-ol. The suggested starting dose for Phase II studies is 12.5 mg/sq m given every 21 days for i.v. 4-DMDR with dose escalation by 2.5 mg/sq m in the absence of myelotoxicity. For p.o. 4-DMDR, the suggested starting dose is 40 mg/sq m given every 21 days with escalation by 10 mg/sq m if no myelotoxicity is observed.

FoxO1-dependent induction of acute myeloid leukemia by osteoblasts in mice.

Osteoblasts, the bone forming cells, affect self-renewal and expansion of hematopoietic stem cells (HSCs), as well as homing of healthy hematopoietic cells and tumor cells into the bone marrow. Constitutive activation of ß-catenin in osteoblasts is sufficient to alter the differentiation potential of myeloid and lymphoid progenitors and to initiate the development of acute myeloid leukemia (AML) in mice. We show here that Notch1 is the receptor mediating the leukemogenic properties of osteoblast-activated ß-catenin in HSCs. Moreover, using cell-specific gene inactivation mouse models, we show that FoxO1 expression in osteoblasts is required for and mediates the leukemogenic properties of ß-catenin. At the molecular level, FoxO1 interacts with ß-catenin in osteoblasts to induce expression of the Notch ligand, Jagged-1. Subsequent activation of Notch signaling in long-term repopulating HSC progenitors induces the leukemogenic transformation of HSCs and ultimately leads to the development of AML. These findings identify FoxO1 expressed in osteoblasts as a factor affecting hematopoiesis and provide a molecular mechanism whereby the FoxO1/activated ß-catenin interaction results in AML. These observations support the notion that the bone marrow niche is an instigator of leukemia and raise the prospect that FoxO1 oncogenic properties may occur in other tissues.

13C-NMR study of the binding of [1-13C]galactose-labelled N-acetyllactosamine and [1-13C]galactose-enriched hen ovalbumin to soybean agglutinin.

The binding of the tide compounds to soybean agglutinin was investigated using 13C-NMR spectroscopy. The equilibrium constant for the binding of N-acetyllactosamine was found to be smaller than that obtained for the binding of ovalbumin (1.1 X 10(3) vs. 7.4 X 10(3) M-1). Only two binding sites per lectin tetramer were determined for the binding of ovalbumin, which is half the number of binding sites reported for the binding of small ligands to the lectin. Steric interference between the bulky ovalbumin molecules is believed to be the reason for the observed decrease in the apparent number of binding sites on the lectin.

An early transient increase of intracellular Na+ may be one of the first components of the mitogenic signal. Direct detection by 23Na-NMR spectroscopy in quiescent 3T3 mouse fibroblasts stimulated by growth factors.

23Na-NMR spectroscopy was designed to allow for continuous recording of intracellular Na+ in 3T3 fibroblasts stimulated by serum growth-factors in the presence of ion transport inhibitors. The metabolic state of cells at rest and following stimulation was monitored by 31P-NMR spectra of ATP and related high-energy phosphates. The study demonstrates that early activation of ion transporters by addition of serum is marked by the appearance of transient increase of the intracellular Na+, beginning 3 min after addition of serum to quiescent culture and lasting approx. 20 min. The initial rise in cellular Na+ results from an increased activity of the bumetanide-sensitive Na+/K+/Cl- cotransport and of the amiloride-sensitive Na+/H+ antiport. It is suppressed by any one of these inhibitors. Subsequent activation of the ouabain-sensitive Na+/K(+)-ATPase results in an increased Na+ efflux, leading to a return of intracellular Na+ to its initial baseline. Previous work had shown that the early activation of bumetanide-sensitive and amiloride sensitive ion-transporters by growth-factors was essential for induction of cell division, at least in some cell types. Preventing ion activation by adding ion-transport inhibitors lead to the inhibition of DNA synthesis 18 h later. This process was reversible upon elimination of these inhibitors. Even though alternative non-specific effects of these inhibitors cannot be ruled out, the observed transient peak in intracellular Na+ may be one of the earliest components of the mitogenic signal. On the basis of previous works, its effect seems to be related to the activation of Ca(2+)-dependent and cyclic AMP second messenger pathways. The different mechanisms whereby the activated Na+/K+/Cl- cotransport and the Na+/H+ antiport contribute to this signal need to be further investigated.

Subcellular distribution of free and esterified forms of vitamin A in the pigment epithelium of the retina and in liver.

1. The distribution of vitamin A was examined in various subcellular fractions of rat liver and bovine retinal pigment epithelium. In rat liver, the major portion of the vitamin is in the cytosol, whereas in pigment epithelium, it is concentrated mainly in the microsomes. The microsomal vitamin A of pigment epithelium is tightly bound to membranes, as shown by the inability to release it except by organic solvent extraction or incubation with Triton X-100. 2. In both tissues, two different forms of cytosol vitamin A could be distinguished by ultracentrifugation. The major portion in liver is in the floating lipid phase and consists mainly of retinyl ester. The remainder (less than 10% of the total) is in the underlying infranatant; about 90% of the vitamin A in this fraction is esterified. By contrast, two-thirds of the vitamin A of pigment epithelial cell cytosol is in the infranatant; it consists of both esterified and unesterified retinol. The floating layer in the pigment epithelial cytosol consists entirely of retinyl ester. 3. These two forms of cytosol vitamin A in the pigment epithelium could also be separated by gel filtration on Sephadex G-100 which yielded two distinct fluorescent peaks. The first, which appeared in the void volume and corresponded in all probability to the floating layer obtained by ultracentrifugation, consisted only of retinyl ester. The second peak, which was eluted in approximately the same position as myoglobin, contained only unesterified retinol. It was abolished completely by preincubation with pronase. These findings support the view that the second peak represents the endogenous retinol-retinol binding protein complex of pigment epithelial cytosol. The fluorescent enhancement of the retinol bound to protein in this peak was about 4--5-fold compared to retinol in organic solvents.

Enzymatic esterification of vitamin A in the pigment epithelium of bovine retina.

The kinetic properties and subcellular distribution of an esterifying enzyme in the pigment epithelium of bovine retina have been studied using both [1-3H]retinol and [3H]retinol bound to cellular retinol-binding protein as substrates. The most active esterifying fraction in pigment epithelial cell preparations was the microsomes, but the lysosome plus mitochondria fraction also showed some activity, probably due to endoplasmic reticulum present as an impurity. The microsomal enzyme showed optimum activity at pH 7.5, and the reaction was linear up to 30 microgram protein and for the first 10-15 min. The apparent Km values were 16.6 . 10(-6) and 5.5 . 10(-6) M for [3H]retinol and bound [3H]retinol, respectively. This is the first time that retinol bound to cellular retinol-binding protein has been shown to undergo metabolic transformation. The microsomal esterifying activity was destroyed by boiling for 1 min, or after freezing for 2 months. No clear requirement for ATP, CoA or fatty acid could be demonstrated. Of all the other tissues examined under the same experimental conditions as those used for the pigment epithelium, only intestine showed measurable activity. With larger amounts of tissue protein and longer incubation periods, activity was also detectable in microsomes of liver, testis and retina.

Phase I and II study of fludarabine phosphate in leukemia: therapeutic efficacy with delayed central nervous system toxicity.

Fludarabine phosphate (9-beta-D-arabinofuranosyl-2-fluoroadenine), a novel purine nucleoside, has demonstrated excellent preclinical antitumor activity and little toxicity in phase I clinical trials. We evaluated the clinical use of fludarabine given as a continuous intravenous (IV) infusion for remission induction in patients with relapsed or refractory leukemia. Thirty infusions were administered to 25 patients. At doses less than or equal to 125 mg/m2/d for five days, only three of 17 patients cleared their bone marrow of leukemic cells, and none achieved complete remission (CR). Nine patients received doses of 150 mg/m2/d for five days or 125 mg/m2/d for seven days. Four of these patients achieved CR (three patients with acute nonlymphoblastic leukemia (ANLL), one patient with acute lymphoblastic leukemia (ALL]. However, severe CNS toxicity was encountered in five patients at the two highest dose levels. Initial symptoms of neurotoxicity were delayed from 21 to 43 days after starting treatment and consisted of optic neuritis, cortical blindness, altered mental status, and generalized seizure. Only one patient regained visual and neurologic function; four other patients experienced progressive neurologic deterioration and died. Clinicopathologic evaluation suggested widespread, severe demyelination as the etiology of these reactions. We conclude that fludarabine is an effective drug for remission induction in acute leukemia. However, doses required to achieve CR are associated with unacceptable CNS toxicity. In view of its potent antileukemic activity, further evaluation of fludarabine at lower doses (less than or equal to 75 mg/m2/d for five days) may be warranted in combination with other chemotherapeutic agents for the treatment of patients with acute leukemia.

13-cis-Retinoic acid does not increase the true remission rate and the duration of true remission (induced by cytotoxic chemotherapy) in patients with chronic phase chronic myelogenous leukemia.

Treatment of chronic phase chronic myelogenous leukemia with hydroxyurea or busulfan rarely induces cytogenetic (true) remissions. Intensive chemotherapy induces brief true remissions in approximately 50% of patients. We added 13-cis-retinoic acid to daunorubicin, cytosine arabinoside, and thioguanine to determine if it could increase the incidence and duration of remission induced by cytotoxic chemotherapy. Of the 17 evaluable patients, one patient (6%) achieved complete remission, and seven patients (41%) achieved partial remissions. The median duration of remission was 1.6 months. We conclude that 13-cis-retinoic acid does not increase the incidence and duration of remission in chronic phase chronic myelogenous leukemia.