NDPK-D (NM23-H4)-mediated externalization of cardiolipin enables elimination of depolarized mitochondria by mitophagy.

Mitophagy is critical for cell homeostasis. Externalization of the inner mitochondrial membrane phospholipid, cardiolipin (CL), to the surface of the outer mitochondrial membrane (OMM) was identified as a mitophageal signal recognized by the microtubule-associated protein 1 light chain 3. However, the CL-translocating machinery remains unknown. Here we demonstrate that a hexameric intermembrane space protein, NDPK-D (or NM23-H4), binds CL and facilitates its redistribution to the OMM. We found that mitophagy induced by a protonophoric uncoupler, carbonyl cyanide m-chlorophenylhydrazone (CCCP), caused externalization of CL to the surface of mitochondria in murine lung epithelial MLE-12 cells and human cervical adenocarcinoma HeLa cells. RNAi knockdown of endogenous NDPK-D decreased CCCP-induced CL externalization and mitochondrial degradation. A R90D NDPK-D mutant that does not bind CL was inactive in promoting mitophagy. Similarly, rotenone and 6-hydroxydopamine triggered mitophagy in SH-SY5Y cells was also suppressed by knocking down of NDPK-D. In situ proximity ligation assay (PLA) showed that mitophagy-inducing CL-transfer activity of NDPK-D is closely associated with the dynamin-like GTPase OPA1, implicating fission-fusion dynamics in mitophagy regulation.

Subsequent malignant neoplasms in pediatric cancer patients treated with and without hematopoietic SCT.

Pediatric cancer patients are at increased risk of subsequent malignant neoplasms (SMNs). However, little is known about the contribution of hematopoietic SCT (HSCT) to the development of SMNs. The objective of this study was to compare the incidence of SMNs in a population cohort of childhood cancer survivors treated with and without HSCT. A cohort of 7986 children (age 0-14 years) diagnosed with cancer in the province of Ontario, Canada between 1985 and 2009 was identified in POGONIS (Pediatric Oncology Group of Ontario Networked Information System), a population-based active cancer registry, and linked to a clinical HSCT database. Among this cohort, 796 patients had an HSCT as part of their primary treatment. Of the 375 allogeneic HSCT patients, 14 (3.7%) developed a SMN at a median follow-up of 12.3 years (range: 2.0-22.9 years). Of the 421 autologous HSCT patients, 8 (1.9%) developed a SMN at a median of 4.5 years (range: 1.3-14.3 years). Of the 7190 patients who did not receive an HSCT, 160 (2.2%) developed a SMN at a median follow-up of 6.8 years (range: 0.0-24.9 years). The 15-year cumulative incidence of SMN was 3.1% among the allogeneic HSCT group, 2.5% among the autologous group and 2.3% in the non-HSCT group. The cumulative incidence curves for the allogeneic HSCT and non-transplant groups only diverged after ~15 years from primary diagnosis. Our findings further corroborate the observation that children who undergo allogeneic HSCT are at a significantly increased risk of developing SMN compared with pediatric cancer survivors treated without HSCT.

Incidence and predictors of treatment-related mortality in paediatric acute leukaemia in El Salvador.

Survival rates among children with leukaemia in low-income countries are lower than those in high-income countries. This has been attributed in part to higher treatment-related mortality (TRM). We examined the demographics, treatment, and outcomes of paediatric patients in El Salvador with acute lymphoblastic leukaemia (ALL) or acute myeloid leukaemia (AML) to determine the incidence, causes, and risk factors for TRM. Two trained data managers collected data prospectively; no patients were excluded. Biological, socioeconomic and nutritional predictors were examined. A total of 469 patients with ALL and 78 patients with AML were included. The 2-year cumulative incidence of TRM was significantly higher among children with AML (35.4+/-6.4%) than those with ALL (12.5+/-1.7%; P<0.0001). However, the proportion of deaths attributable to the toxicity of treatment did not differ significantly between AML (25/47, 53.2%) and ALL (55/107, 51.4%; P=0.98). Among children with ALL, low monthly income (P=0.04) and low parental education (P=0.02) significantly increased the risk of TRM. Among children with AML, biological, socioeconomic, and nutritional variables were not associated with TRM. In this low-income country, toxic death significantly contributes to mortality in both ALL and AML. A better understanding of the effect of socioeconomic status on TRM may suggest specific strategies for patients with ALL.

Serial controlled N-of-1 trials of topical vitamin E as prophylaxis for chemotherapy-induced oral mucositis in paediatric patients.

The objectives were (1) to determine whether in children undergoing doxorubicin-containing chemotherapy, topical vitamin E decreases an objective measurement of oral mucositis compared to placebo, and (2) to assess the feasibility of an innovative trial design in paediatric cancer, combining N-of-1 trials using Bayesian meta-analysis. We conducted a series of N-of-1, double-blinded, randomised controlled trials in children > or = 6 years of age receiving repeated cycles of identical doxorubicin-containing chemotherapy. Each study cycle was followed by topical vitamin E (800 mg) or placebo. We enroled 16 children and 45 post chemotherapy cycles were randomised to vitamin E (N=22) or placebo (N=23). There was no difference in objective mucositis scores with a mean score of 0.2 with vitamin E and 0.3 with placebo. Topical vitamin E does not reduce doxorubicin-induced oral mucositis in children. The use of N-of-1 studies and Bayesian meta-analysis may facilitate the study of some therapies in paediatric oncology.

Evolution of genotypic and phenotypic resistance during chronic treatment with the fusion inhibitor T-1249.

T-1249 is a peptide HIV fusion inhibitor (FI) previously under development for use in FI-naive and experienced patients. Here we present prospectively planned longitudinal analyses of FI resistance during 48 weeks of T-1249 dosing in patients with extensive prior FI exposure. T1249-105 was a single-arm rollover study in patients with prior resistance to enfuvirtide (ENF) and 10 days of T-1249 functional monotherapy exposure. The phenotype and genotype of plasma virus envelopes were analyzed at baseline and at study weeks 8, 16, and 48. At study entry, viruses had a geometric mean decrease in susceptibility to ENF of 51.8-fold but to T-1249 of 1.8-fold; extensive genotypic resistance to ENF was observed. A median viral load response of - 1.5 log(10) copies/ml was observed at week 2 that was partially sustained (- 0.5 log(10) copies/ml) through 48 weeks. Resistance to T-1249 gradually increased to a geometric mean 92.7-fold decrease from FI-naive baseline; this occurred concomitant with further evolution of gp41 amino acids 36-45, most commonly the G36D (n = 6, 16%) or N43K (n = 9, 24%) substitutions. A novel substitution, A50V (n = 12, 32%), was also common, as were the N126K and S138A substitutions in heptad-repeat 2 (HR-2). These data point toward a primary role for the gp41 36-45 locus in modulating FI binding and suggest that residues in HR-2 may contribute in a more limited manner to development of peptide FI resistance. These data also point toward a substantial genetic barrier and fitness cost to development of resistance to next-generation fusion inhibitors.

Characterization of envelope glycoprotein gp41 genotype and phenotypic susceptibility to enfuvirtide at baseline and on treatment in the phase III clinical trials TORO-1 and TORO-2.

Enfuvirtide (T-20) is the first entry inhibitor approved for treatment of HIV infection and acts by inhibiting conformational changes in the viral envelope protein gp41 that are necessary for fusion of the virus and host cell membranes. Here we present genotypic and phenotypic data on viral envelopes obtained at baseline (n = 627) and after 48 weeks of enfuvirtide treatment (n = 302) from patients in the TORO (T-20 versus Optimized Regimen Only)-1 and -2 phase III pivotal studies. The amino acid sequence at residues 36-45 of gp41 was highly conserved at baseline except for polymorphism of approximately 16% at position 42. Substitutions within gp41 residues 36-45 on treatment were observed in virus from 92.7% of patients who met protocol defined virological failure criteria and occurred in nearly all cases (98.8%) when decreases in susceptibility to enfuvirtide from baseline of greater than 4-fold were observed. Consistent with previous observations, a wide range of baseline susceptibilities (spanning 3 logs) was observed; however, lower in vitro baseline susceptibility was not significantly associated with a decreased virological response in vivo. Virological response was also independent of baseline coreceptor tropism and viral subtype.

A pilot study of ondansetron plus metopimazine vs. ondansetron monotherapy in children receiving highly emetogenic chemotherapy: a Bayesian randomized serial N-of-1 trials design.

GOALS OF WORK: Chemotherapy-induced nausea and vomiting is problematic in paediatric brain tumour treatment protocols which often discourage the use of corticosteroids as anti-emetics. The dopamine receptor antagonist, metopimazine, is an effective anti-emetic in combination with ondansetron in adults. The present study was designed to assess its efficacy in children with cancer, a group in which it has not been studied previously. PATIENTS AND METHODS: We conducted a series of randomized, multiple-crossover, double-blind, placebo-controlled N-of-1 trials comparing ondansetron/metopimazine with ondansetron monotherapy in children with brain tumours receiving highly emetogenic therapy and combined the individual results using Bayesian statistical modeling. MAIN RESULTS: Ten of twelve enrolled patients completed at least one chemotherapy cycle on study (median=2.5 cycles, range 1-11). Two patients were unable to complete any cycles, and a further three patients withdrew from the study prior to completing all cycles because of an inability to tolerate the taste of the study drug. Combination therapy increased the proportion of days during which patients had no emesis (overall odds ratio=1.52, 95% credible region=0.32-6.40, probability of odds ratio>1=72%), decreased the number of emetic episodes per day (overall rate ratio=0.67, 95% credible region=0.15-3.14, probability of rate ratio<1=75%) and decreased parents' ratings of their child's distress. The drug was more effective during the delayed chemotherapy phase than the acute phase. No adverse events were attributed to metopimazine. CONCLUSIONS: Based on this pilot study, we believe that the high likelihood that metopimazine is an effective adjunct to ondansetron monotherapy suggests that this combination therapy is worthy of further study in children receiving emetogenic chemotherapy.

Deficiency in mitochondrial anionic phospholipid synthesis impairs cell wall biogenesis.

Cardiolipin (CL) is the signature lipid of the mitochondrial membrane and plays a key role in mitochondrial physiology and cell viability. The importance of CL is underscored by the finding that the severe genetic disorder Barth syndrome results from defective CL composition and acylation. Disruption of PGS1, which encodes the enzyme that catalyses the committed step of CL synthesis, results in loss of the mitochondrial anionic phospholipids phosphatidylglycerol and CL. The pgs1Delta mutant exhibits severe growth defects at 37 degrees C. To understand the essential functions of mitochondrial anionic lipids at elevated temperatures, we isolated suppressors of pgs1Delta that grew at 37 degrees C. The present review summarizes our analysis of suppression of pgs1Delta growth defects by a mutant that has a loss-of-function mutation in KRE5, a gene involved in cell wall biogenesis.

Impact of human immunodeficiency virus type 1 gp41 amino acid substitutions selected during enfuvirtide treatment on gp41 binding and antiviral potency of enfuvirtide in vitro.

Enfuvirtide (ENF), a novel human immunodeficiency virus type 1 (HIV-1) fusion inhibitor, has potent antiviral activity against HIV-1 both in vitro and in vivo. Resistance to ENF observed after in vitro passaging was associated with changes in a three-amino-acid (aa) motif, GIV, at positions 36 to 38 of gp41. Patients with ongoing viral replication while receiving ENF during clinical trials acquired substitutions within gp41 aa 36 to 45 in the first heptad repeat (HR-1) of gp41 in both population-based plasma virus sequences and proviral DNA sequences from isolates showing reduced susceptibilities to ENF. To investigate their impact on ENF susceptibility, substitutions were introduced into a modified pNL4-3 strain by site-directed mutagenesis, and the susceptibilities of mutant viruses and patient-derived isolates to ENF were tested. In general, susceptibility decreases for single substitutions were lower than those for double substitutions, and the levels of ENF resistance seen for clinical isolates were higher than those observed for the site-directed mutant viruses. The mechanism of ENF resistance was explored for a subset of the substitutions by expressing them in the context of a maltose binding protein chimera containing a portion of the gp41 ectodomain and measuring their binding affinity to fluorescein-labeled ENF. Changes in binding affinity for the mutant gp41 fusion proteins correlated with the ENF susceptibilities of viruses containing the same substitutions. The combined results support the key role of gp41 aa 36 to 45 in the development of resistance to ENF and illustrate that additional envelope regions contribute to the ENF susceptibility of fusion inhibitor-naïve viruses and resistance to ENF.

Emergence and evolution of enfuvirtide resistance following long-term therapy involves heptad repeat 2 mutations within gp41.

The objective of this study was to track the evolution of sequence changes in both the heptad region 1 (HR1) and HR2 domains of gp41 associated with resistance to enfuvirtide (ENF) in a patient cohort receiving long-term ENF treatment. We studied 17 highly antiretroviral agent-experienced patients receiving long-term ENF treatment with virological rebound or a lack of suppression. Sixty-two samples obtained after between 5 and 107 weeks of ENF therapy were analyzed. Baseline samples from 15 of these 17 patients were available for analysis. Viruses from five samples from four patients were also sequenced after the cessation of ENF therapy. Drug susceptibilities were assessed by a pseudotype virus reporter assay. We identified HR1 and HR2 sequence changes over time in relation to the baseline sequences. Mutations in HR1 (amino acids 36 to 45) were noted in all cases, including previously unreported changes N42Q/H and N43Q. In addition to a range of HR2 sequence changes at polymorphic sites, isolates from 6 of 17 (35%) patients developed an S138A substitution in the HR2 domain at least 8 weeks after the start of ENF treatment and also subsequent to the first emergence of HR1 mutations. In most, but not all, cases the S138A mutation accompanied HR1 mutations at position 43. Molecular modeling demonstrates the close proximity of S138A with amino acids 40 and 45 in HR1. Of note, isolates in samples available from four patients demonstrated the loss of both the HR1 and the S138A HR2 mutations following the cessation of therapy. We show that the S138A HR2 mutation increased the level of resistance by approximately threefold over that conferred by the HR1 mutation N43D. Continual evolution of HR1 in the domain from amino acids 36 to 45 was observed during long-term ENF therapy. We have identified, for the first time, an ENF resistance-associated HR2 mutation, S138A, which appeared in isolates from 6 of 17 patients with virological failure and demonstrated its potential to contribute to drug resistance. We propose that this represents a possible secondary and/or compensatory mutation, particularly when it coexists with mutations at position 43 in HR-1.

Use of paediatric versus adult oncology treatment centres by adolescents 15-19 years old: the Canadian Childhood Cancer Surveillance and Control Program.

The aim of this study was to evaluate the treatment patterns of adolescents with cancer in Canada to ensure this population is receiving the most appropriate care. The Treatment and Outcome Surveillance (TOS) system was compared with the Canadian Cancer Registry (CCR) to estimate the proportion of adolescents (15-19 years) treated in Canadian paediatric oncology centres from 1995 to 2000 inclusive. Using TOS, the demographic, disease, and clinical characteristics of adolescents treated in paediatric versus adult centres in the Prairies were compared and differences were tested statistically. Approximately 30% of Canadian adolescents with cancer were treated in a paediatric centre. Adolescents treated in an adult centre were older at diagnosis and more likely to have carcinoma or germ cell tumours. The time between symptom onset and first treatment was longer for these adolescents, primarily due to the time between first health-care contact and assessment by a treating oncologist or surgeon. They were less likely to be enrolled in a clinical trial. These results suggest that care for adolescents with cancer in Canada is less satisfactory than for younger children, and can be improved.

Health-related quality of life (HRQL) scores reported from parents and their children with chronic illness differed depending on utility elicitation method.

OBJECTIVE: To describe the relationship between health-related quality of life (HRQL) as measured by utility when elicited from parents and their children with chronic illness. STUDY DESIGN AND SETTING: We enrolled families of children admitted for cancer chemotherapy and those attending outpatient rheumatology, hemophilia and bone marrow transplantation clinics. Children in grade 6 or higher were included. The child's HRQL was rated by parent and child using the Standard Gamble (SG), Visual Analogue Scale (VAS), Time Trade-Off (TTO), and Health Utilities Index Mark 2/3 (HUI2 and HUI3). RESULTS: 22 families were included. The mean parent SG was 0.92 +/- 0.09, which was similar to the mean SG elicited from their children of 0.92 +/- 0.10. The parent and child SG were moderately concordant (ICC=0.64, 95% CI=0.30, 0.83; P=.0005). In contrast, TTO scores were not concordant (ICC=0.14, 95% CI=-0.29, 0.53; P=.3), with parents (mean TTO=0.77 +/- 0.31) rating HRQL worse than children (mean TTO=0.92 +/- 0.11; P=.04). Similarly, the mean parent HUI2 of 0.82 +/- 0.22 was lower than the child HUI2 of 0.95 +/- 0.07; P=.02 and HUI2 were not concordant (ICC=0.11, 95% CI=-0.35, 0.53; P=.3) between parents and children. CONCLUSION: Parents and children rate HRQL similarly according to SG, but parents rate HRQL significantly worse using TTO and HUI2.

Validity of a modified standard gamble elicited from parents of a hospital-based cohort of children.

OBJECTIVES: To examine the validity of a modified standard gamble (Mod SG) (nondeath baseline) by comparing these scores to SG (death baseline), time trade off (TTO), visual analog scale (VAS), Health Utilities Index (HUI), and Child Health Questionnaire (CHQ). METHODS: Respondents were parents of in-patients with cancer receiving chemotherapy and parents of children without cancer attending outpatient clinics. Construct validity was determined by comparing a priori hypotheses to actual correlations between measures. Discriminant validity was examined by anticipating that in-patients with cancer would have lower HRQL than outpatients. RESULTS: 85 families were included. Both Mod SG and SG were moderately correlated with TTO (r=0.50 and r=0.49; P<.01 for both). Both Mod SG and SG were moderately correlated with TTO (r=0.47 and r=0.05, P<0.002 for both). CONCLUSION: The Mod SG did not perform better than SG. Two nonoverlapping groups of HRQL measures were demonstrated.

Construct validation of the Health Utilities Index and the Child Health Questionnaire in children undergoing cancer chemotherapy.

The objective of this study was to evaluate the construct validity of two questionnaire-based measures of health-related quality of life (HRQL) in children undergoing cancer chemotherapy: the Health Utilities Index (HUI) and the Child Health Questionnaire (CHQ). Subjects were children hospitalised for chemotherapy. To examine construct validity: (1). a priori expected relations between CHQ concepts and HUI attributes were examined; (2). HUI and CHQ summary scores were compared to visual analogue scale (VAS) scores. Ease of completion was rated using a 5-point categorical scale and completion time was recorded. A total of 36 subjects were included. The maximum score was seen in 15 (47%) of HUI3 assessments. As predicted, CHQ body pain was moderately correlated with HUI3 pain (r=0.51), CHQ physical functioning was moderately correlated with HUI2 mobility (r=0.58) and CHQ mental health was moderately correlated with HUI2 emotion (r=0.53). Only the CHQ psychosocial subscale (and not HUI) was correlated with VAS (r=0.44). The CHQ and the HUI were both easy to use. The HUI questionnaires required less time to complete (mean=3.1, s.d.=1 min) compared with CHQ (mean=13.1, s.d.=3.4 min, P<0.0001). In conclusion, HUI and CHQ demonstrated construct validity in children undergoing cancer chemotherapy. The Health Utilities Index is subject to a ceiling effect whereas CHQ requires more time to complete.

Epi-inositol regulates expression of the yeast INO1 gene encoding inositol-1-P synthase.

Myo-inositol exerts behavioral effects in animal models of psychiatric disorders and is effective in clinical trials in psychiatric patients. Interestingly, epi-inositol exerts behavioral effects similar to myo-inositol, even though epi-inositol is not a substrate for synthesis of phosphatidylinositol. We postulated that the behavioral effects of epi-inositol may be due to its effects on gene expression. Yeast INO1expression was measured in northern blots. INM1 was determined by beta-galactosidase activity in a strain containing the fusion gene INM1-lacZintegrated into the genome. Epi-inositol affects regulation of expression of the INO1 gene (encoding inositol-1-P synthase), even though it cannot support growth of an inositol auxotroph (suggesting that, as in mammalian cells, it is not incorporated into phosphatidylinositol). Like myo-inositol, although to a lesser extent, epi-inositol causes a significant reduction in INO1 expression, and reverses the lithium- or valproate-induced increase in INO1 expression. However, it does not affect regulation of INM1 (encoding inositol monophosphatase), the expression of which is up-regulated by myo-inositol. The observed regulatory effects of epi-inositol on expression of the most highly regulated gene in the inositol biosynthetic pathway may help to explain how this inositol isomer can exert behavioral effects without being incorporated into phosphatidylinositol.

Immunologic and virologic analyses of an acutely HIV type 1-infected patient with extremely rapid disease progression.

The immunologic and virologic factors that impact on the rate of disease progression after acute infection with human immunodeficiency virus (HIV) type 1 are poorly understood. A patient with an extraordinarily rapid disease course leading to AIDS-associated death within 6 months of infection was studied intensively for the presence of anti-HIV immune reactivities as well as changes in the genetic and biologic properties of virus isolates. Although altered humoral responses were evident, the most distinctive immunologic feature was a nearly complete absence of detectable HIV-specific CTL responses. In addition to a rapid decline in CD3+CD4+ cells, elevated percentages of CD8+CD45RA+ and CD8+CD57+ cells and diminished CD8+CD45R0+ and CD8+CD28+ cells were evident. Primary viral isolates recovered throughout the course of infection exhibited limited sequence diversity. Cloned viral envelopes were found to have unusually broad patterns of coreceptor usage for cell-cell fusion, although infectivity studies yielded no evidence of infection via these alternative receptors. The infectivity studies demonstrated that these isolates and their envelopes maintained an R5 phenotype throughout the course of disease. The absence of demonstrable anti-HIV CTL reactivities, coupled with a protracted course of seroconversion, highlights the importance of robust HIV-specific immune responses in the control of disease progression.

Phase I trial of a twice-daily regimen of amifostine with ifosfamide, carboplatin, and etoposide chemotherapy in children with refractory carcinoma.

BACKGROUND: Amifostine protects normal tissues against chemotherapy and radiation-induced toxicity without loss of antitumor effects. Evidence suggests that multiple daily doses of amifostine may improve its cytoprotective effects. The purpose of this study was to assess the dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD) of twice-daily doses of amifostine with ifosfamide, carboplatin, and etoposide (ICE) chemotherapy for children with refractory malignancies and to determine the pharmacokinetic properties of amifostine, WR-1065, and the disulfide metabolites of amifostine. METHODS: Patients with refractory malignancies were treated with amifostine 15 minutes before and 2 hours after chemotherapy with ifosfamide (3 g/m(2) per dose on Days 1 and 2) and carboplatin (635 mg/m(2) on Day 3). Etoposide was administered on Days 1 and 2 (150 mg/m(2)). The starting dose of amifostine was 740 mg/m(2). Pharmacokinetic studies were performed after the first dose of amifostine. RESULTS: Twelve patients received 23 courses of ICE and amifostine. Dose-limiting toxicities for amifostine at 740 mg/m(2) were somnolence and anxiety. The other Grade 3 and 4 toxicities included asymptomatic, reversible hypocalcemia, vomiting, and reversible hypotension. At a dose of 600 mg/m(2), amifostine was well tolerated. Hypocalcemia, due to rapid, transient suppression of parathyroid hormone production, required close monitoring and aggressive intravenous calcium supplementation. Pharmacokinetic studies revealed high interpatient variability with rapid plasma clearance of amifostine and WR-1065. The median elimination half-life of amifostine (9.3 minutes) and WR-1065 (15 minutes) was much shorter than the disulfide metabolites (74.4 minutes). CONCLUSIONS: The recommended pediatric dose of amifostine for a twice-daily regimen is 600 mg/m(2) per dose (1200 mg/m(2)/day) with DLTs of anxiety and somnolence, lower than the previously recommended single dose of 1650 mg/m(2).

Delayed nausea and vomiting in children receiving antineoplastics.

BACKGROUND: The nature and prevalence of delayed antineoplastic-induced nausea and vomiting have not been well-described in children. This study describes the extent of delayed nausea and vomiting in children receiving antineoplastic agents as well as the drug therapies initiated in an attempt to prevent or manage it. PROCEDURE: All children receiving antineoplastics were eligible for study entry. The date and time of each emetic episode were recorded on each day antineoplastics were given and for 3 days thereafter. Nausea was self-assessed daily by children who were older than 3 years and were not developmentally delayed. Diet was also assessed daily. The emetic response, median nausea rating and median diet achieved were described. RESULTS: The emetic response of 124 children who received 174 antineoplastic cycles was evaluated. Most cycles (137/174;79%) were not associated with delayed vomiting. Cycles which included cisplatin, carboplatin, or cyclophosphamide; involved antineoplastic therapy given over 2 or more consecutive days; or were accompanied by vomiting during the acute phase were associated with a significantly higher incidence of delayed vomiting. Moderate to severe nausea was reported on 58% (267/459) of study days. No antiemetics were given on most study days (412/522;79%); nevertheless, most of the study days (381/412;93%) which were unaccompanied by antiemetic support during the delayed phase were completely free from vomiting. Antiemetics were most often given as single agents (ondansetron: 54 study days; dimenhydrinate: 17 study days; dexamethasone: 6 study days). Diet was largely unaffected during the study period. CONCLUSIONS: Antineoplastic-induced delayed nausea and vomiting may be less prevalent in children than in adults. Routine antiemetic administration during the delayed phase may not be warranted in all patients. Med Pediatr Oncol 2001;37:115-121.

Molecular basis for cell tropism of CXCR4-dependent human immunodeficiency virus type 1 isolates.

Laboratory isolates of human immunodeficiency virus type 1 (HIV-1) that utilize CXCR4 as a coreceptor infect primary human macrophages inefficiently even though these express a low but detectable level of cell surface CXCR4. In contrast, infection of primary macrophages by primary CXCR4-tropic HIV-1 isolates is readily detectable. Here, we provide evidence suggesting that this difference in cell tropism results from a higher requirement for cell surface CXCR4 for infection by laboratory HIV-1 isolates. Transfected COS7 cells that express a high level of CD4 but a low level of CXCR4 were infected significantly more efficiently by two primary CXCR4-tropic HIV-1 isolates compared to the prototypic laboratory HIV-1 isolate IIIB. More importantly, overexpression of either wild-type or signaling-defective CXCR4 on primary macrophages dramatically enhanced the efficiency of infection by the laboratory HIV-1 isolate yet only modestly enhanced infection by either primary CXCR4-tropic virus. Overexpression of CD4 had, in contrast, only a limited effect on macrophage infection by the laboratory HIV-1, although infection by the primary isolates was markedly enhanced. We therefore conclude that the laboratory CXCR4-tropic HIV-1 isolate exhibits a significantly higher CXCR4 requirement for efficient infection than do the primary CXCR4-tropic isolates and that this difference can explain the poor ability of the laboratory HIV-1 isolate to replicate in primary macrophages. More generally, we propose that the cell tropisms displayed by different strains of HIV-1 in culture can largely be explained on the basis of differential requirements for cell surface CD4 and/or coreceptor expression levels.

Lithium and valproate decrease inositol mass and increase expression of the yeast INO1 and INO2 genes for inositol biosynthesis.

Bipolar affective disorder (manic-depressive illness) is a chronic, severe, debilitating illness affecting 1-2% of the population. The Food and Drug Administration-approved drugs lithium and valproate are not completely effective in the treatment of this disorder, and the mechanisms underlying their therapeutic effects have not been established. We are employing genetic and molecular approaches to identify common targets of lithium and valproate in the yeast Saccharomyces cerevisiae. We show that both drugs affect molecular targets in the inositol metabolic pathway. Lithium and valproate cause a decrease in intracellular myo-inositol mass and an increase in expression of both a structural (INO1) and a regulatory (INO2) gene required for inositol biosynthesis. The opi1 mutant, which exhibits constitutive expression of INO1, is more resistant to inhibition of growth by lithium but not by valproate, suggesting that valproate may inhibit the Ino1p-catalyzed synthesis of inositol 1-phosphate. Consistent with this possibility, growth in valproate leads to decreased synthesis of inositol monophosphate. Thus, both lithium and valproate perturb regulation of the inositol biosynthetic pathway, albeit via different mechanisms. This is the first demonstration of increased expression of genes in the inositol biosynthetic pathway by both lithium and valproate. Because inositol is a key regulator of many cellular processes, the effects of lithium and valproate on inositol synthesis have far-reaching implications for predicting genetic determinants of responsiveness and resistance to these agents.