292 research outputs found
DNA alkylation and interstrand cross-linking by treosulfan
The anti-tumour drug treosulfan (L-threitol 1,4-bismethanesulphonate, Ovastat) is a prodrug for epoxy compounds by converting non-enzymatically to L-diepoxybutane via the corresponding monoepoxide under physiological conditions. The present study supports the hypothesis that this conversion of treosulfan is required for cytotoxicity in vitro. DNA alkylation and interstrand cross-linking of plasmid DNA is observed after treosulfan treatment, but this is again produced via the epoxide species. Alkylation occurs at guanine bases with a sequence selectivity similar to other alkylating agents such as the nitrogen mustards. In treosulfan-treated K562 cells, cross-links form slowly, reaching a peak at approximately 24 h. Incubation of K562 cells with preformed epoxides shows faster and more efficient DNA cross-linking. © 1999 Cancer Research Campaig
Recommended from our members
Cannabigerol is a novel, well-tolerated appetite stimulant in pre-satiated rats
Rationale
The appetite-stimulating properties of cannabis are well documented and have been predominantly attributed to the hyperphagic activity of the psychoactive phytocannabinoid, ∆9-tetrahydrocannabinol (∆9-THC). However, we have previously shown that a cannabis extract devoid of ∆9-THC still stimulates appetite, indicating that other phytocannabinoids also elicit hyperphagia. One possible candidate is the non-psychoactive phytocannabinoid cannabigerol (CBG), which has affinity for several molecular targets with known involvement in the regulation of feeding behaviour.
Objectives
The objective of the study was to assess the effects of CBG on food intake and feeding pattern microstructure.
Methods
Male Lister hooded rats were administered CBG (30–120 mg/kg, per ora (p.o.)) or placebo and assessed in open field, static beam and grip strength tests to determine a neuromotor tolerability profile for this cannabinoid. Subsequently, CBG (at 30–240 mg/kg, p.o.) or placebo was administered to a further group of pre-satiated rats, and hourly intake and meal pattern data were recorded over 2 h.
Results
CBG produced no adverse effects on any parameter in the neuromotor tolerability test battery. In the feeding assay, 120–240 mg/kg CBG more than doubled total food intake and increased the number of meals consumed, and at 240 mg/kg reduced latency to feed. However, the sizes or durations of individual meals were not significantly increased.
Conclusions
Here, we demonstrate for the first time that CBG elicits hyperphagia, by reducing latency to feed and increasing meal frequency, without producing negative neuromotor side effects. Investigation of the therapeutic potential of CBG for conditions such as cachexia and other disorders of eating and body weight regulation is thus warranted
Variable viral clearance despite adequate ganciclovir plasma levels during valganciclovir treatment for cytomegalovirus disease in D+/R- transplant recipients
ABSTRACT: BACKGROUND: Valganciclovir, the oral prodrug of ganciclovir, has been demonstrated equivalent to iv ganciclovir for CMV disease treatment in solid organ transplant recipients. Variability in ganciclovir exposure achieved with valganciclovir could be implicated as a contributing factor for explaining variations in the therapeutic response. This prospective observational study aimed to correlate clinical and cytomegalovirus (CMV) viral load response (DNAemia) with ganciclovir plasma concentrations in patients treated with valganciclovir for CMV infection/disease. METHODS: Seven CMV D+/R- transplant recipients (4 kidney, 2 liver and 1 heart) were treated with valganciclovir (initial dose was 900-1800 mg/day for 3-6.5 weeks, followed by 450-900 mg/day for 2-9 weeks). DNAemia was monitored by real time quantitative PCR and ganciclovir plasma concentration was measured at trough (Ctrough) and 3 h after drug administration (C3h) by HPLC. RESULTS: Four patients presented with CMV syndrome, two had CMV tissue-invasive disease after prophylaxis discontinuation, and one liver recipient was treated pre-emptively for asymptomatic rising CMV viral load 5 weeks post-transplantation in the absence of prophylaxis. CMV DNAemia decreased during the first week of treatment in all recipients except in one patient (median decrease: -1.2 log copies/mL, range: -1.8 to 0) despite satisfactory ganciclovir exposure (AUC0-12 = 48 mg.h/L, range for the 7 patients: 40-118 mg.h/L). Viral clearance was obtained in five patients after a median of time of 34 days (range: 28-82 days). Two patients had recurrent CMV disease despite adequate ganciclovir exposure (65 mg.h/L, range: 44-118 mg.h/L). CONCLUSIONS: Valganciclovir treatment for CMV infection/disease in D+/R- transplant recipients can thus result in variable viral clearance despite adequate ganciclovir plasma concentrations, probably correlating inversely with anti-CMV immune responses after primary infection
Caloric beverage consumption patterns in Mexican children
<p>Abstract</p> <p>Background</p> <p>Mexico has seen a very steep increase in child obesity level. Little is known about caloric beverage intake in this country as well as all other countries outside a few high income countries. This study examines overall patterns and trends in all caloric beverages from two nationally representative surveys from Mexico.</p> <p>Methods</p> <p>The two nationally representative dietary intake surveys (1999 and 2006) from Mexico are used to study caloric beverage intake in 17, 215 children. The volume (ml) and caloric energy (kcal) contributed by all beverages consumed by the sample subjects were measured. Results are weighted to be nationally representative.</p> <p>Results</p> <p>The trends from the dietary intake surveys showed very large increases in caloric beverages among pre-school and school children. The contribution of whole milk and sugar-sweetened juices was an important finding. Mexican pre-school children consumed 27.8% of their energy from caloric beverages in 2006 and school children consumed 20.7% of their energy from caloric beverages during the same time. The three major categories of beverage intake are whole milk, fruit juice with various sugar and water combinations and carbonated and noncarbonated sugared-beverages.</p> <p>Conclusion</p> <p>The Mexican government, greatly concerned about obesity, has identified the large increase in caloric beverages from whole milk, juices and soft drinks as a key target and is initiating major changes to address this problem. They have already used the data to shift 20 million persons in their welfare and feeding programs from whole to 1.5% fat milk and in a year will shift to nonfat milk. They are using these data to revise school beverage policies and national regulations and taxation policies related to an array of less healthful caloric beverages.</p
α-Bromoacryloyl derivative of distamycin A (PNU 151807): a new non-covalent minor groove DNA binder with antineoplastic activity
Influence of taste disorders on dietary behaviors in cancer patients under chemotherapy
<p>Abstract</p> <p>Objectives</p> <p>To determine the relationship between energy and nutrient consumption with chemosensory changes in cancer patients under chemotherapy.</p> <p>Methods</p> <p>We carried out a cross-sectional study, enrolling 60 subjects. Cases were defined as patients with cancer diagnosis after their second chemotherapy cycle (n = 30), and controls were subjects without cancer (n = 30). Subjective changes of taste during treatment were assessed. Food consumption habits were obtained with a food frequency questionnaire validated for Mexican population. Five different concentrations of three basic flavors --sweet (sucrose), bitter (urea), and a novel basic taste, umami (sodium glutamate)-- were used to measure detection thresholds and recognition thresholds (RT). We determine differences between energy and nutrient consumption in cases and controls and their association with taste DT and RT.</p> <p>Results</p> <p>No demographic differences were found between groups. Cases showed higher sweet DT (6.4 vs. 4.4 μmol/ml; p = 0.03) and a higher bitter RT (100 vs. 95 μmol/ml; <it>p </it>= 0.04) than controls. Cases with sweet DT above the median showed significant lower daily energy (2,043 vs.1,586 kcal; p = 0.02), proteins (81.4 vs. 54 g/day; <it>p </it>= 0.01), carbohydrates (246 vs.192 g/day; <it>p </it>= 0.05), and zinc consumption (19 vs.11 mg/day; <it>p </it>= 0.01) compared to cases without sweet DT alteration. Cases with sweet DT and RT above median were associated with lower completion of energy requirements and consequent weight loss. There was no association between flavors DT or RT and nutrient ingestion in the control group.</p> <p>Conclusion</p> <p>Changes of sweet DT and bitter RT in cancer patients under chemotherapy treatment were associated with lower energy and nutrient ingestion. Taste detection and recognition thresholds disorders could be important factors in malnutrition development on patients with cancer under chemotherapy treatment.</p
Effect of extended morning fasting upon ad libitum lunch intake and associated metabolic and hormonal responses in obese adults
Background/Objectives:
Breakfast omission is positively associated with obesity and increased risk of disease. However, little is known about the acute effects of extended morning fasting upon subsequent energy intake and associated metabolic/regulatory factors in obese adults.
Subjects/Methods:
In a randomised cross-over design, 24 obese men (n=8) and women (n=16) extended their overnight fast by omitting breakfast consumption or ingesting a typical carbohydrate-rich breakfast of 2183±393 kJ (521±94 kcal), before an ad libitum pasta lunch 3 h later. Blood samples were obtained throughout the day until 3 h post lunch and analysed for hormones implicated in appetite regulation, along with metabolic outcomes and subjective appetite measures.
Results:
Lunch intake was unaffected by extended morning fasting (difference=218 kJ, 95% confidence interval −54 kJ, 490 kJ; P=0.1) resulting in lower total intake in the fasting trial (difference=−1964 kJ, 95% confidence interval −1645 kJ, −2281 kJ; P<0.01). Systemic concentrations of peptide tyrosine–tyrosine and leptin were lower during the afternoon following morning fasting (Pless than or equal to0.06). Plasma-acylated ghrelin concentrations were also lower following the ad libitum lunch in the fasting trial (P<0.05) but this effect was not apparent for total ghrelin (Pgreater than or equal to0.1). Serum insulin concentrations were greater throughout the afternoon in the fasting trial (P=0.05), with plasma glucose also greater 1 h after lunch (P<0.01). Extended morning fasting did not result in greater appetite ratings after lunch, with some tendency for lower appetite 3 h post lunch (P=0.09).
Conclusions:
We demonstrate for the first time that, in obese adults, extended morning fasting does not cause compensatory intake during an ad libitum lunch nor does it increase appetite during the afternoon. Morning fasting reduced satiety hormone responses to a subsequent lunch meal but counterintuitively also reduced concentrations of the appetite-stimulating hormone-acylated ghrelin during the afternoon relative to lunch consumed after breakfast
Crisis discharges and readmission risk in acute psychiatric male inpatients
<p>Abstract</p> <p>Background</p> <p>Severe pressures on beds in psychiatric services have led to the implementation of an early ("crisis") discharge policy in the Western Cape, South Africa. The study examined the effect of this policy and length of hospital stay (LOS) on readmission rates in one psychiatric hospital in South Africa.</p> <p>Methods</p> <p>Discharge summaries of adult male patients (<it>n </it>= 438) admitted to Stikland Psychiatric Hospital during 2004 were retrospectively examined. Each patient's clinical course was then analysed for the period between January 1<sup>st</sup>, 2004, and August 31<sup>st</sup>, 2006.</p> <p>Results</p> <p>Although shorter LOS was associated with decreased readmission rates, the effect of crisis discharges was far more powerful. Patients discharged as usual had a far lower risk of readmission than those discharged due to bed pressures (i.e. crisis discharge).</p> <p>Conclusion</p> <p>Increased risks associated with the early discharge policy necessitate the urgent review of the current management of bed shortages in this inpatient facility. The strengthening of community initiatives, particularly assertive outreach could be a way forward.</p
Comparative acute efficacy and tolerability of OROS and immediate release formulations of methylphenidate in the treatment of adults with attention-deficit/hyperactivity disorder
<p>Abstract</p> <p>Background</p> <p>The main aim of this study was to compare the safety and efficacy of IR MPH administered three times daily to those of once daily OROS-MPH.</p> <p>Methods</p> <p>Subjects were outpatient adults satisfying full diagnostic criteria for DSM-IV ADHD between 19 and 60 years of age. Data from two independently conducted 6-week placebo controlled, randomized clinical trials of IR-MPH (tid) and of OROS-MPH were pooled to create three study groups: Placebo (N = 116), IR-MPH (tid) (N = 102) and OROS-MPH (N = 67).</p> <p>Results</p> <p>Eight-five percent (N = 99) of placebo treated subjects, 77% (N = 79) of the IR-MPH (tid) treated subjects, and 82% (N = 55) of the OROS-MPH treated subjects completed the 6-week trial. Total daily doses at endpoint were 80.9 ± 31.9 mg, 74.8 ± 26.2 mg, and 95.4 ± 26.3 mg in the OROS-MPH, IR-MPH (tid), and placebo groups, respectively. At endpoint, 66% (N = 44) of subjects receiving OROS-MPH and 70% (N = 71) of subjects receiving IR-MPH (tid) were considered responders compared with 31% (N = 36) on placebo.</p> <p>Conclusion</p> <p>Comparison of data from two similarly designed, large, randomized, placebo-controlled, trials, showed that equipotent daily doses of once daily OROS-MPH had similar efficacy to that of TID administered IR MPH.</p> <p>Trial Registration</p> <p>The trial of OROS-MPH was registered at clinicaltrials.gov, number NCT00181571.</p
- …