Topical preparations for the treatment of mild-to-moderate acne vulgaris: systematic review and network meta-analysis.

BACKGROUND: Acne is very common and can have a substantial impact on wellbeing. Guidelines suggest first-line management with topical treatments, but there is little evidence regarding which treatments are most effective. OBJECTIVES: To identify the most effective and best tolerated topical treatments for acne using network meta-analysis. METHODS: CENTRAL, MEDLINE, Embase and World Health Organization Trials Registry were searched from inception to June 2020 for randomized trials that included participants with mild/moderate acne. Primary outcomes were self-reported improvement in acne, and trial withdrawal. Secondary outcomes included change in lesion counts, Investigator's Global Assessment, change in quality of life and total number of adverse events. Network meta-analysis was undertaken using a frequentist approach. Risk of bias was assessed using the Cochrane Risk of Bias Tool and confidence in evidence was assessed using CINeMA. RESULTS: A total of 81 papers were included, reporting 40 trials with a total of 18 089 participants. Patient Global Assessment of Improvement was reported in 11 trials. Based on the pooled network estimates, compared with vehicle, benzoyl peroxide (BPO) was effective (35% vs. 26%) for improving self-reported acne. The combinations of BPO with adapalene (54% vs. 35%) or with clindamycin (49% vs. 35%) were ranked more effective than BPO alone. The withdrawal of participants from the trial was reported in 35 trials. The number of patients withdrawing owing to adverse events was low for all treatments. Rates of withdrawal were slightly higher for BPO with adapalene (2·5%) or clindamycin (2·7%) than BPO (1·6%) or adapalene alone (1·0%). Overall confidence in the evidence was low. CONCLUSIONS: Adapalene in combination with BPO may be the most effective treatment for acne but with a slightly higher incidence of withdrawal than monotherapy. Inconsistent reporting of trial results precluded firmer conclusions.

Greater extracellular free-water in first-episode psychosis predicts better neurocognitive functioning.

Free Water Imaging is a novel diffusion magnetic resonance (MR) imaging method that is able to separate changes affecting the extracellular space from those that reflect changes in neuronal cells and processes. A previous Free Water Imaging study in schizophrenia identified significantly greater extracellular water volume in the early stages of the disorder; however, its clinical and functional sequelae have not yet been investigated. Here, we applied Free Water Imaging to a larger cohort of 63 first-episode patients with psychosis and 70 healthy matched controls to better understand the functional significance of greater extracellular water. We used diffusion MR imaging data and the Tract-Based Spatial Statistics analytic pipeline to first analyze fractional anisotropy (FA), the most commonly employed metric for assessing white matter. This comparison was then followed by Free Water Imaging analysis, where two parameters, the fractional volume of extracellular free-water (FW) and cellular tissue FA (FA-t), were estimated and compared across the entire white matter skeleton between groups, and correlated with cognitive measures at baseline and following 12 weeks of antipsychotic treatment. Our results indicated lower FA across the whole brain in patients compared with healthy controls that overlap with significant increases in FW, with only limited decreases in FA-t. In addition, higher FW correlated with better neurocognitive functioning following 12 weeks of antipsychotic treatment. We believe this is the first study to suggest that an extracellular water increase during the first-episode of psychosis, which may be indicative of an acute neuroinflammatory process, and/or cerebral edema may predict better functional outcome.

Bridging classical and quantum mechanics.

Using a watt balance and a frequency comb, a mass-energy equivalence is derived. The watt balance compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck constant is established by the practical realization of the electrical units derived from the Josephson and the quantum Hall effects. By using frequency combs to measure velocities and acceleration of gravity, the unit of mass can be realized from a set of three defining constants: the Planck constant h, the speed of light c, and the hyperfine splitting frequency of 133Cs.

Structurally diverse MDM2-p53 antagonists act as modulators of MDR-1 function in neuroblastoma.

BACKGROUND: A frequent mechanism of acquired multidrug resistance in human cancers is overexpression of ATP-binding cassette transporters such as the Multi-Drug Resistance Protein 1 (MDR-1). Nutlin-3, an MDM2-p53 antagonist, has previously been reported to be a competitive MDR-1 inhibitor. METHODS: This study assessed whether the structurally diverse MDM2-p53 antagonists, MI-63, NDD0005, and RG7388 are also able to modulate MDR-1 function, particularly in p53 mutant neuroblastoma cells, using XTT-based cell viability assays, western blotting, and liquid chromatography-mass spectrometry analysis. RESULTS: Verapamil and the MDM2-p53 antagonists potentiated vincristine-mediated growth inhibition in a concentration-dependent manner when used in combination with high MDR-1-expressing p53 mutant neuroblastoma cell lines at concentrations that did not affect the viability of cells when given alone. Liquid chromatography-mass spectrometry analyses showed that verapamil, Nutlin-3, MI-63 and NDD0005, but not RG7388, led to increased intracellular levels of vincristine in high MDR-1-expressing cell lines. CONCLUSIONS: These results show that in addition to Nutlin-3, other structurally unrelated MDM2-p53 antagonists can also act as MDR-1 inhibitors and reverse MDR-1-mediated multidrug resistance in neuroblastoma cell lines in a p53-independent manner. These findings are important for future clinical trial design with MDM2-p53 antagonists when used in combination with agents that are MDR-1 substrates.

Carboplatin dosage: prospective evaluation of a simple formula based on renal function.

A dosage formula has been derived from a retrospective analysis of carboplatin pharmacokinetics in 18 patients with pretreatment glomerular filtration rates (GFR) in the range of 33 to 136 mL/min. Carboplatin plasma clearance was linearly related to GFR (r = 0.85, P less than .00001) and rearrangements of the equation describing the correlation gave the dosage formula dose (mg) = target area under the free carboplatin plasma concentration versus time curve (AUC) x (1.2 x GFR + 20). In a prospective clinical and pharmacokinetic study the formula was used to determine the dose required to treat 31 patients (GFR range, 33 to 135 mL/min) with 40 courses of carboplatin. The target AUC was escalated from 3 to 8 mg carboplatin/mL/min. Over this AUC range the formula accurately predicted the observed AUC (observed/predicted ratio 1.24 +/- 0.11, r = 0.886) and using these additional data, the formula was refined. Dose (mg) = target AUC x (GFR + 25) is now the recommended formula. AUC values of 4 to 6 and 6 to 8 mg/mL. min gave rise to manageable hematological toxicity in previously treated and untreated patients, respectively, and hence target AUC values of 5 and 7 mg/mL min are recommended for single-agent carboplatin in these patient groups. Pharmacokinetic modeling demonstrated that the formula was reasonably accurate regardless of whether a one- or two-compartment model most accurately described carboplatin pharmacokinetics, assuming that body size did not influence nonrenal clearance. The validity of this assumption was demonstrated in 13 patients where no correlation between surface area and nonrenal clearance was found (r = .31, P = .30). Therefore, the formula provides a simple and consistent method of determining carboplatin dose in adults. Since the measure of carboplatin exposure in the formula is AUC, and not toxicity, it will not be influenced by previous or concurrent myelosuppressive therapy or supportive measures. The formula is therefore applicable to combination and high-dose studies as well as conventional single-agent therapy, although the target AUC for carboplatin will need to be redefined for combination chemotherapy.

The synergistic interaction of MEK and PI3K inhibitors is modulated by mTOR inhibition.

BACKGROUND: Combined targeting of MAPK and PI3K signalling pathways may be necessary for optimal therapeutic activity in cancer. This study evaluated the MEK inhibitors AZD6244 and PD0325901, alone and in combination with the dual mTOR/PI3K inhibitor NVP-BEZ235 or the PI3K inhibitor GDC-0941, in three colorectal cancer cell lines. METHODS: Growth inhibition, survival and signal transduction were measured using the Sulforhodamine B assay, clonogenicity and western blotting, respectively, in HCT116, HT29 and DLD1 cell lines. RESULTS: All MEK/PI3K inhibitor combinations exhibited marked synergistic growth inhibition; however, GDC-0941 displayed greater synergy in combination with either MEK inhibitor. NVP-BEZ235 exhibited stronger inhibition of 4EBP1 phosphorylation, and similar inhibition of S6 and AKT phosphorylation, compared with GDC-0941. Both PD0325901 and AZD6244 inhibited ERK phosphorylation, and with MEK/PI3K inhibitor combinations inhibition of S6 phosphorylation was increased. The reduced synergy exhibited by NVP-BEZ235 in combination with MEK inhibitors, compared with GDC-0941, may be due to inhibition of mTOR, and the addition of the mTORC1/2 inhibitor KU0063794 compromised the synergy of GDC-0941:PD0325901 combinations. CONCLUSION: These studies confirm that dual targeting of PI3K and MEK can induce synergistic growth inhibition; however, the combination of specific PI3K inhibitors, rather than dual mTOR/PI3K inhibitors, with MEK inhibitors results in greater synergy.

Lifestyle and health behaviour change support in traditional acupuncture: a mixed method survey study of reported practice (UK).

AIMS: Complementary medicine therapists such as traditional acupuncturists are a large resource for supporting public health targets to improve health behaviours. Our objectives were to determine the prevalence and patterns of UK acupuncturists' provision of lifestyle change support, test theory-based hypotheses about facilitators and barriers to supporting lifestyle changes and to explore associated characteristics and attitudes. METHODS: A mixed methods design in which British Acupuncture Council members (Sept 2019-April 2020) completed an online questionnaire assessing prevalence of lifestyle change support, typical patterns across patients and behaviours, Theory of Planned Behaviour constructs, practitioner characteristics and open-text responses regarding additional behaviours and clinical decisions to introduce lifestyle change. RESULTS: Three hundred fifty-two traditional acupuncturists participated (Mean age = 51.5 years, SD 9.9; 81.8% (n = 288) female). 57.7% (n = 203) reported offering support for lifestyle change during their most recent consultation. 91.7% (n = 323) reported supporting lifestyle change 'always or most of the time' for patients with chronic conditions and 67.9% (n = 239) reported this for patients with acute conditions. The pattern of typical support for different health behaviours ranged from 44.6% (n = 157) for smoking reduction (acute conditions) to 95.2% (n = 335) for diet support (chronic conditions). A linear regression model found that frequency of support for lifestyle change in acute patients was predicted by acupuncturists' attitudes to both clinical role and importance of health behaviours, confidence in their ability to provide lifestyle change support and use of fewer behaviour change techniques. The decision to first offer lifestyle change support was guided by perceived patient receptiveness, whether presenting condition/diagnosis were likely to improve with lifestyle change and whether a strong therapeutic relationship was established. CONCLUSIONS: Traditional acupuncturists' reports suggest their work supports key public health targets for promoting healthy behaviours. Less frequent support for alcohol/smoking may reflect user characteristics but may suggest training needs for acupuncturists. Increase could be made for support in acute presentations, however the importance of patient receptiveness, linking advice to condition, and therapeutic alliance should be explored further. There may be important differences between acupuncture practice and mainstream healthcare (e.g. high level of contact, longer visits, holistic approach) which impact mechanisms of action of behaviour change.

Thiothymidine combined with UVA as a potential novel therapy for bladder cancer.

BACKGROUND: Thiothymidine (S(4)TdR) can be incorporated into DNA and sensitise cells to DNA damage and cell death following exposure to UVA light. Studies were performed to determine if the combination of S(4)TdR and UVA could be an effective treatment for bladder cancer. METHODS: Uptake and incorporation of S(4)TdR was determined in rat and human bladder tumour cell lines. Measures of DNA crosslinking and apoptosis were also performed. In vivo activity of the combination of S(4)TdR and UVA was investigated in an orthotopic model of bladder cancer in rats. RESULTS: Thiothymidine (200 µM) replaced up to 0.63% of thymidine in rat and tumour bladder cancer cells. The combination of S(4)TdR (10-200 µM) and UVA (1-5 kJ m(-2)) caused apoptosis and cell death at doses that were not toxic alone. Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S(4)TdR into DNA (up to 20-fold at IC(5)) and further sensitised cells to UVA. Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein. Intravenous administration of S(4)TdR, in combination with UVA delivered directly to the bladder, resulted in an antitumour effect in three of five animals treated. CONCLUSION: These data indicate that the combination of S(4)TdR and UVA has potential as a treatment for bladder cancer, and give some insight into the mechanism of action. Further work is necessary to optimise the delivery of the two components.

Biosecurity-based interventions and strategies to reduce Campylobacter spp. on poultry farms.

The prevention and control of Campylobacter colonization of poultry flocks are important public health strategies for the control of human campylobacteriosis. A critical review of the literature on interventions to control Campylobacter in poultry on farms was undertaken using a systematic approach. Although the focus of the review was on aspects appropriate to the United Kingdom poultry industry, the research reviewed was gathered from worldwide literature. Multiple electronic databases were employed to search the literature, in any language, from 1980 to September 2008. A primary set of 4,316 references was identified and scanned, using specific agreed-upon criteria, to select relevant references related to biosecurity-based interventions. The final library comprised 173 references. Identification of the sources of Campylobacter in poultry flocks was required to inform the development of targeted interventions to disrupt transmission routes. The approach used generally involved risk factor-based surveys related to culture-positive or -negative flocks, usually combined with a structured questionnaire. In addition, some studies, either in combination or independently, undertook intervention trials. Many of these studies were compromised by poor design, sampling, and statistical analysis. The evidence for each potential source and route of transmission on the poultry farm was reviewed critically, and the options for intervention were considered. The review concluded that, in most instances, biosecurity on conventional broiler farms can be enhanced and this should contribute to the reduction of flock colonization. However, complementary, non-biosecurity-based approaches will also be required in the future to maximize the reduction of Campylobacter-positive flocks at the farm level.

Influence of production system on the rate of onset of Campylobacter colonization in chicken flocks reared extensively in the United Kingdom.

1. Because thermophilic Campylobacter spp. are common in chicken flocks reared extensively, cross-sectional and longitudinal studies were carried out on organic and free-range farms to determine the onset of colonisation (lag phase) and likely sources of flock infection. 2. For 14 organic and 14 free range flocks, there was a difference in lag phases, with the former being colonized at a mean of 14·1 d in comparison with 31·6 d for the latter. Whereas most free-range flocks became colonized when released on to pasture, those reared organically were usually colonized at the housed brooding stage. 3. Further study of organic flocks on three farms over 7 successive crop cycles confirmed that colonisation was strongly influenced by the prevailing husbandry conditions and was not a consequence of the length of the rearing period. 4. Molecular epidemiological investigations on a farm showing the shortest lag phase, using PFGE typing with two different restriction enzymes (SmaI and KpnI) and flaA SVR sequence typing, revealed that potential sources of colonisation for organic chickens were already present on the farm at the time of chick placement. Such sources included the ante area of the brooding house, surrounding pasture and other livestock being kept on the farm. 5. Overall, the study demonstrated that, under UK conditions, the prevalence of colonisation was greater in extensive flocks (95-100%) than it was for conventional broilers (55%), similar to the situation in other countries, but all three management systems showed comparable levels of caecal carriage in positive birds (log(10)/g 6·2-6·7).

Pre-clinical evaluation of cyclin-dependent kinase 2 and 1 inhibition in anti-estrogen-sensitive and resistant breast cancer cells.

BACKGROUND: Cellular proliferation, driven by cyclin-dependent kinases (CDKs) and their cyclin partners, is deregulated in cancer. Anti-estrogens, such as tamoxifen, antagonise estrogen-induced ERalpha transactivation of cyclin D1, resulting in reduced CDK4/6 activity, p27(Kip1)-mediated inhibition of CDK2 and growth arrest. We hypothesised that direct inhibition of CDK2 and CDK1 may overcome the major clinical problem of anti-estrogen resistance. METHODS: The cellular effects of CDK2/1 siRNA knockdown and purine-based CDK2/1 inhibitors, NU2058 and NU6102, were measured in anti-estrogen-sensitive and resistant breast cancer cell lines. RESULTS: CDK2 knockdown caused G1 accumulation, whereas CDK1 depletion caused G2/M slowing, and dual CDK1/2 depletion resulted in further G2/M accumulation and cell death in both anti-estrogen-sensitive and resistant cells, confirming CDK2 and CDK1 as targets for breast cancer therapy. In contrast to tamoxifen, which only affected hormone-sensitive cells, NU2058 and NU6102 reduced CDK2-mediated phosphorylation of pRb, E2F transcriptional activity and proliferation, ultimately resulting in cell death, in both anti-estrogen-sensitive and resistant cells. Both drugs caused G2/M arrest, reflective of combined CDK2/1 knockdown, with a variable degree of G1 accumulation. CONCLUSION: These studies confirm the therapeutic potential of CDK2 and CDK1 inhibitors for cancer therapy, and support their use as an alternative treatment for endocrine-resistant breast cancer.

Selecting for development of fluoroquinolone resistance in a Campylobacter jejuni strain 81116 in chickens using various enrofloxacin treatment protocols.

AIMS: To determine the effect of various enrofloxacin dose regimes on the colonization and selection of resistance in Campylobacter jejuni strain 81116P in experimentally colonized chickens. METHODS AND RESULTS: Two experiments were undertaken, in which 14-day-old chickens were colonized with 1 × 10(7) -1 × 10(9 ) CFU g(-1) Camp. jejuni strain 81116P and then treated with enrofloxacin at 12-500 ppm in drinking water for various times. Caecal colonization levels were determined at various time-points after start-of-treatment, and the susceptibility of recovered isolates to ciprofloxacin was monitored. Resistance was indicated by growth on agar containing 4 µg ml(-1) ciprofloxacin, MICs of 16 µg ml(-1) and the Thr86Ile mutation in gyrA. Enrofloxacin at doses of 12-250 ppm reduced Camp. jejuni colonization over the first 48-72 h after start-of-treatment. The degree of reduction in colonization was dose, but not treatment time, dependent. In all cases, maximal colonization was re-established within 4-6 days. Fluoroquinolone-resistant organisms were recoverable within 48 h of start-of-treatment; after a further 24 h all recovered isolates were resistant. In contrast, a dose of 500 ppm enrofloxacin reduced colonization to undetectable levels within 48 h, and the treated birds remained Campylobacter negative throughout the remaining experimental period. By high pressure liquid chromatography, for all doses, the maximum concentrations of enrofloxacin and ciprofloxacin in the caecal contents were detected at the point of treatment completion. Thereafter, levels declined to undetectable by 7 days post-treatment withdrawal. CONCLUSIONS: In a model using chickens maximally colonized with Camp. jejuni 81116P, treatment with enrofloxacin, at doses of 12-250 ppm in drinking water, enables the selection, and clonal expansion, of fluoroquinolone-resistant organisms. However, this is preventable by treatment with 500 ppm of enrofloxacin. SIGNIFICANCE AND IMPACT OF THE STUDY: Treatment of chickens with enrofloxacin selects for resistance in Camp. jejuni in highly pre-colonized birds. However, a dose of 500 ppm enrofloxacin prevented the selection of resistant campylobacters.

Investigation of the presence and protective effects of maternal antibodies against Campylobacter jejuni in chickens.

The role of maternal antibodies in the lag phase of Campylobacter positivity, widely observed in commercial broiler flocks, was investigated. The results indicate that 3-wk-old birds derived from a commercial flock are more susceptible to colonization with Campylobacter jejuni than 1-to-2-wk-old birds. This increasing susceptibility parallels the loss of maternally derived, circulating, anti-Campylobacter, immunoglobulin Y antibodies as detected by enzyme-linked immunosorbent assay. The role of these antibodies in resistance to colonization was further investigated using progeny from breeder flocks of known Campylobacter status. These results confirmed that maternal antibodies confer partial protection against Campylobacter colonization on young chickens (1-2 wk old). This protection was directed against challenge with both homologous and heterologous strains of C. jejuni and even against strains with a high colonization potential. However, evidence presented indicates that newly hatched chicks, with the highest levels of maternal antibodies, were as susceptible to Campylobacter challenge as 3-wk-old birds. This conundrum was investigated further, and an increase in resistance was detected from 1 to 3 days of age. The reasons for this are, as yet, unknown, but the observation validates the use of newly hatched chicks in models of Campylobacter colonization. Moreover, this high susceptibility in the first few days of life may explain the occasional early flock colonization observed, especially when environmental exposure to Campylobacter is high, for example, in free-range birds.

Genetic instability is associated with changes in the colonization potential of Campylobacter jejuni in the avian intestine.

AIMS: A panel of pulsed field gel electrophoresis (PFGE) type variants of Campylobacter jejuni, previously identified as of clonal origin, were investigated to determine whether genomic instability could be observed during competitive growth. METHODS AND RESULTS: Upon recovery from frozen storage, some variants had undergone alterations in PFGE profiles, but subsequent culture produced constant genotypes. Individual variants did not display differences in colonization potential when tested in orally challenged 1-day-old chickens. However, competitive colonization using mixtures of two or three PFGE types generally resulted, by 4 weeks postchallenge, in one predominant PFGE type in all birds. For some variant mixtures, a minor population of novel PFGE types was detected in individual birds. The creation of new variants appeared to be dependent on the extent of competition and of the individual host. Genomic rearrangements most likely explain this increase in genetic diversity, apparently without the involvement of natural transformation or plasmid acquisition. In vitro cultivation of mixed inoculations were again selected for particular variants; but genetic diversity was not generated, suggesting that the selection pressures in vitro differed from those active in vivo. CONCLUSION: These observations support the hypothesis that by generating genetic diversity, C. jejuni can improve its phenotypic fitness to survive and colonize subsequent hosts. SIGNIFICANCE AND IMPACT OF THE STUDY: The consequences of such observations for the development of campylobacter control strategies for poultry may be substantial.

Enterohaemorrhagic and other Shiga toxin-producing Escherichia coli (STEC): Where are we now regarding diagnostics and control strategies?

Escherichia coli comprises a highly diverse group of Gram-negative bacteria and is a common member of the intestinal microflora of humans and animals. Generally, such colonization is asymptomatic; however, some E. coli strains have evolved to become pathogenic and thus cause clinical disease in susceptible hosts. One pathotype, the Shiga toxigenic E. coli (STEC) comprising strains expressing a Shiga-like toxin is an important foodborne pathogen. A subset of STEC are the enterohaemorrhagic E. coli (EHEC), which can cause serious human disease, including haemolytic uraemic syndrome (HUS). The diagnosis of EHEC infections and the surveillance of STEC in the food chain and the environment require accurate, cost-effective and timely tests. In this review, we describe and evaluate tests now in routine use, as well as upcoming test technologies for pathogen detection, including loop-mediated isothermal amplification (LAMP) and whole-genome sequencing (WGS). We have considered the need for improved diagnostic tools in current strategies for the control and prevention of these pathogens in humans, the food chain and the environment. We conclude that although significant progress has been made, STEC still remains an important zoonotic issue worldwide. Substantial reductions in the public health burden due to this infection will require a multipronged approach, including ongoing surveillance with high-resolution diagnostic techniques currently being developed and integrated into the routine investigations of public health laboratories. However, additional research requirements may be needed before such high-resolution diagnostic tools can be used to enable the development of appropriate interventions, such as vaccines and decontamination strategies.

Treating cat allergy with monoclonal IgG antibodies that bind allergen and prevent IgE engagement.

Acute allergic symptoms are caused by allergen-induced crosslinking of allergen-specific immunoglobulin E (IgE) bound to Fc-epsilon receptors on effector cells. Desensitization with allergen-specific immunotherapy (SIT) has been used for over a century, but the dominant protective mechanism remains unclear. One consistent observation is increased allergen-specific IgG, thought to competitively block allergen binding to IgE. Here we show that the blocking potency of the IgG response to Cat-SIT is heterogeneous. Next, using two potent, pre-selected allergen-blocking monoclonal IgG antibodies against the immunodominant cat allergen Fel d 1, we demonstrate that increasing the IgG/IgE ratio reduces the allergic response in mice and in cat-allergic patients: a single dose of blocking IgG reduces clinical symptoms in response to nasal provocation (ANCOVA, p = 0.0003), with a magnitude observed at day 8 similar to that reported with years of conventional SIT. This study suggests that simply augmenting the blocking IgG/IgE ratio may reverse allergy.

Multi-year study of human metapneumovirus infection at a large US Midwestern Medical Referral Center.

BACKGROUND: Because of its recent identification, few multi-year epidemiologic studies of hMPV infection have been reported. OBJECTIVE: We sought to retrospectively describe hMPV infections among patients evaluated by a large US Midwestern referral laboratory. STUDY DESIGN: Clinical specimens were submitted to a large US Midwest referral hospital from 1 October 2001 to 18 May 2004. RT-PCR was used to retrospectively screen the clinical specimens for human metapneumovirus. Demographic and clinical data were retrieved. RESULTS: 34 (2.6%) of 1294 specimens were hMPV positive. Among these, 21 (62%) were culture positive and available for genetic typing. A previously considered rare genotype of hMPV, B1, was the most common single genotype identified, comprising 9 (43%) of the 21 isolates. Multivariate logistic regression modeling identified patients aged 0.4-9 years (OR=8.9; 95% CI=2.0-38.5) and those under intensive care (OR=3.2; 95% CI=1.1-8.7) as more likely to have hMPV infection than their peers. CONCLUSION: In this large referral hospital viral assays more often had evidence of hMPV when they were collected from children receiving intensive care.

In vitro and in vivo antitumor activity of ZENECA ZD0490, a recombinant ricin A-chain immunotoxin for the treatment of colorectal cancer.

ZENECA ZD0490 is a recombinant ricin A-chain-containing immunotoxin that recognizes an antigen that is expressed on approximately 65% of colorectal tumors. The antigen CA242 is recognized by a mouse monoclonal antibody designated C242. C242 antibody was conjugated to recombinant ricin A-chain via a methyl-hindred disulfide linker which confers in vivo stability. ZD0490 was extremely potent against colorectal cell lines CoLo201 and CoLo205, which express the CA242 antigen. ZD0490 activity was determined in vitro by both protein synthesis inhibition (50% inhibitory concentrations of 1-20 ng/ml after 24-h exposure) and clonogenic assay (76-95% cell kill after 24-h exposure to a 50% inhibitory concentration for protein synthesis inhibition; > 99.99% cell kill at 1000 ng/ml). This in vitro activity was translated to in vivo efficacy where single dose i.v. administration of 2.5 mg/kg of ZD0490 was sufficient to induce substantial growth delays of both CoLo201 and CoLo205 s.c. tumors in nude mice. This growth delay equates to between 40 and 60% inhibition of tumor protein synthesis as quantified by an in vivo [14C]leucine incorporation assay. Using this technique, it was shown that protein synthesis inhibition persisted for at least 96 h after a single dose of ZD0490. Administration of the same total dose given as daily doses over 5 days did not alter the antitumor efficacy of ZD0490 in either the growth delay or the protein synthesis inhibition assays. The in vitro and in vivo activity of ZD0490 detailed in this paper show that this novel immunotoxin is worthy of clinical evaluation, which is currently under way in the United Kingdom.

Etoposide pharmacokinetics in children: the development and prospective validation of a dosing equation.

Pharmacokinetic studies of etoposide administered at 100-200 mg/m2 to 33 children are described. Twenty-seven studies were performed in children aged < 10 years. Repeat studies were performed in 11 patients. Median pharmacokinetic parameters were as follows: plasma clearance, 26 ml/min/m2; volume of distribution, 4.9 liters/m2; area under the etoposide plasma concentration-time curve (AUC), 3.9 mg/ml x min per 100 mg/m2. Interindividual variability in pharmacokinetic parameters was large (coefficient of variation (CV) = 30, 28, and 27%, respectively) in comparison with intraindividual variability (CV = 12, 14, and 12%, respectively). Variability in AUC was much greater in those patients treated with 150-200 mg/m2 etoposide than with 100 mg/m2 (CV, 35 versus 13%) and was related to variability in renal function and prior exposure to cisplatin. Data from the first 20 studies were used to develop pharmacokinetic monitoring equations which were validated in a further 13 patients. The most accurate equation relies upon the elimination constant of 51Cr-EDTA and a single blood specimen taken at the end of the etoposide infusion. [formula: see text] where K = 51Cr-EDTA elimination rate constant. This equation showed no significant bias, and the predictive error was small with respect to AUC calculated according to a two-compartment model. Predictive error did not increase with increasing AUC, whereas a marked increase in predictive error was seen for dosing according to body surface area. Dosing according to body surface area alone led to marked over- or underexposure to etoposide in 8 patients. Pharmacokinetic monitoring using the equation described would have identified these patients and permitted dose modification. This approach provides an accurate means of monitoring etoposide AUC for administration times of 1-4 h without the need for detailed pharmacokinetic sampling. It will allow a significant reduction in the variability of exposure seen with surface area-based dosing.

Multiple membrane transport systems for the uptake of folate-based thymidylate synthase inhibitors.

N10-Propargyl-5,8-dideazafolic acid (CB3717) and 2-desamino-2-methyl-N10-propargyl-5,8-dideazafolic acid (ICI-198,583) are potent folate-based inhibitors of thymidylate synthase. We studied the membrane transport and the growth-inhibitory effects of the two thymidylate synthase inhibitors on human CCRF-CEM leukemia cells with different transport properties for folic acid, reduced folates, and methotrexate (MTX). Membrane transport of [3H]ICI-198,583 can proceed via the high affinity/low capacity reduced folate carrier as supported by findings that (a) uptake of [3H]ICI-198,583 was significantly impaired in CEM cells which have a transport defect for MTX, (b) variants of CEM cells which overproduce the reduced folate carrier system showed a concomitant increase in the uptake of [3H]ICI-198,583 as for [3H]MTX, (c) MTX inhibited transport of [3H]ICI-198,583, and (d) uptake of [3H]ICI-198,583 was inhibited after treatment of CEM cells with an N-hydroxysuccinimide ester of MTX, which is a potent inhibitor of MTX transport. However, a membrane-associated folate-binding protein (FBP) offers another route for entry of CB3717 and ICI-198,583. CEM-FBP cells that have an elevated amount of FBP and do not have a functional reduced folate carrier were 640- and 61-fold more sensitive to CB3717 and ICI-198,583, respectively, compared to control CEM cells expressing the reduced folate/MTX carrier. This high sensitivity was related to a high affinity of the FBP for CB3717 and ICI-198,583 (Kd 2-3 nM), which is only 3-fold lower than for folic acid (Kd 1 nM) but significantly higher than for MTX (Kd 100 nM). Furthermore, after incubation of CEM-FBP cells for 24 h at 10 nM [3H]ICI-198,583, the high affinity binding of the FBP for ICI-198,583 allowed a 600-fold concentrative uptake of [3H]ICI-198,583 and its conversion to polyglutamate forms. These results indicate that multiple folate transport systems may be involved in the uptake of folate-based thymidylate synthase inhibitors.