Water for agriculture: more crop per drop

Global crop production in agriculture depends on water availability. Future scenarios predict increasing occurrence of flash floods and rapidly developing droughts accompanied by heatwaves in humid regions that rely on rain-fed agriculture. It is challenging to maintain high crop yields, even in arid and drought-prone regions that depend on irrigation. The average water demand of crops varies significantly, depending on plant species, development stage, and climate. Most crops, such as maize and wheat, require relatively more water during the vegetative phase compared to the ripening phase. In this review, we explain WUE and options to improve water use and thus crop yield. Nutrient management might represent another possibility to manipulate water uptake and use by plants. An emerging topic involves agroforest co-cultivation, where trees in the system facilitate water transfer through hydraulic lift, benefiting neighbouring crops. Other options to enhance crop yield per water use are discussed.

Selection of Plasmodium falciparum pfcrt and pfmdr1 polymorphisms after treatment with artesunate-amodiaquine fixed dose combination or artemether-lumefantrine in Liberia

Background

Plasmodium falciparum uncomplicated malaria can successfully be treated with an artemisinin-based combination therapy (ACT). However resistance is spreading to the different ACT compounds; the artemisinin derivative and the partner drug. Studies of P. falciparum polymorphisms associated with drug resistance can provide a useful tool to track resistance and guide treatment policy as well as an in-depth understanding of the development and spread of resistance.

Methods

The role of P. falciparum molecular markers in selection of reinfections was assessed in an efficacy trial comparing artesunate–amodiaquine fixed-dose combination with artemether–lumefantrine to treat malaria in Nimba County, Liberia 2008–2009. P. falciparum polymorphisms in pfcrt 76, pfmdr1 86, 184 and 1246, and pfmrp1 876 and 1466 were analysed by PCR-RFLP and pyrosequencing.

Results

High baseline prevalence of pfmdr1 1246Y was found in Nimba county (38 %). Pfmdr1 1246Y and pfmdr1 86+184+1246 haplotypes NYY and YYY were selected in reinfections in the artesunate–amodiaquine arm and pfcrt K76, pfmdr1 N86 and pfmdr1 haplotype NFD were selected in artemether–lumefantrine reinfections. Parasites harbouring pfmdr1 1246Y could reinfect earlier after treatment with artesunate–amodiaquine and parasites carrying pfmdr1 N86 could reinfect at higher lumefantrine concentrations in patients treated with artemether–lumefantrine.

Conclusions

Although treatment is highly efficacious, selection of molecular markers in reinfections could indicate a decreased sensitivity or tolerance of parasites to the current treatments and the baseline prevalence of molecular markers should be closely monitored. Since individual drug levels and the day of reinfection were demonstrated to be key determinants for selection of reinfections, this data needs to be collected and taken into account for accurate evaluation of molecular markers for anti-malarial treatments.

The protocols for the clinical trial was registered with Current Controlled Trials, under the Identifier Number ISRCTN51688713 on 9 October 2008

Tolerability and safety of artesunate-amodiaquine and artemether-lumefantrine fixed dose combinations for the treatment of uncomplicated Plasmodium falciparum malaria: two open-label, randomized trials in Nimba County, Liberia

BACKGROUND

Safety surveillance of widely used artemisinin-based combination therapy (ACT) is essential, but tolerability data in the over five years age group are largely anecdotal.

METHODS

Two open-label, randomized trials were conducted in Nimba County, Liberia: i) the main tolerability trial with 1,000 Plasmodium falciparum malaria patients aged over five years (Study-T), and, ii) an efficacy trial with a secondary objective of collecting tolerability data among 300 children age six to 59 months (Study-E). In both studies patients were randomized to fixed-dose artesunate-amodiaquine (ASAQ Winthrop®) or artemether-lumefantrine (AL, Coartem®), respectively. Clinical- and laboratory-adverse events (AEs) were recorded until day 28.

RESULTS

Study-T: most patients experienced at least one AE. Severe AEs were few, primarily asymptomatic blood system disorders or increased liver enzyme values. No treatment or study discontinuation occurred. Mild or moderate fatigue (39.8% vs 16.3%, p < 0.001), vomiting (7.1% vs 1.6%, p < 0.001), nausea (3.2% vs 1.0%, p = 0.01), and anaemia (14.9% vs 9.8%, p = 0.01) were more frequently recorded in the ASAQ versus AL arm. Study-E: mild or moderate AEs were common, including anaemia, fatigue, vomiting or diarrhoea. The few severe events were asymptomatic blood system disorders and four clinical events (pneumonia, malaria, vomiting and stomatitis).

CONCLUSION

Both ASAQ and AL were well tolerated in patients of all age groups. No unexpected AEs occurred. Certain mild or moderate AEs were more frequent in the ASAQ arm. Standardised safety surveillance should continue for all forms of ACT.

TRIAL REGISTRATION

The protocols were registered with Current Controlled Trials, under the identifier numbers ISRCTN40020296, ISRCTN51688713, (http://www.controlled-trials.com).

Efficacy of artesunate-amodiaquine and artemether-lumefantrine fixed-dose combinations for the treatment of uncomplicated Plasmodium falciparum malaria among children aged six to 59 months in Nimba County, Liberia: an open-label randomized non-inferiority trial

Background

Prospective efficacy monitoring of anti-malarial treatments is imperative for timely detection of resistance development. The in vivo efficacy of artesunate-amodiaquine (ASAQ) fixed-dose combination (FDC) was compared to that of artemether-lumefantrine (AL) among children aged six to 59 months in Nimba County, Liberia, where Plasmodium falciparum malaria is endemic and efficacy data are scarce.

Methods

An open-label, randomized controlled non-inferiority trial compared the genotyping adjusted day 42 cure rates of ASAQ FDC (ASAQ Winthrop®) to AL (Coartem®) in 300 children aged six to 59 months with uncomplicated falciparum malaria. Inclusion was between December 2008 and May 2009. Randomization (1:1) was to a three-day observed oral regimen (ASAQ: once a day; AL: twice a day, given with fatty food). Day 7 desethylamodiaquine and lumefantrine blood-concentrations were also measured.

Results

The day 42 genotyping-adjusted cure rate estimates were 97.3% [95% CI: 91.6-99.1] for ASAQ and 94.2% [88.1-97.2] for AL (Kaplan-Meier survival estimates). The difference in day 42 cure rates was −3.1% [upper limit 95% CI: 1.2%]. These results were confirmed by observed proportion of patients cured at day 42 on the per-protocol population. Parasite clearance was 100% (ASAQ) and 99.3% (AL) on day 3. The probability to remain free of re-infection was 0.55 [95% CI: 0.46-0.63] (ASAQ) and 0.66 [0.57-0.73] (AL) (p = 0.017).

Conclusions

Both ASAQ and AL were highly efficacious and ASAQ was non-inferior to AL. The proportion of patients with re-infection was high in both arms in this highly endemic setting. In 2010, ASAQ FDC was adopted as the first-line national treatment in Liberia. Continuous efficacy monitoring is recommended.

Trial registration

The protocols were registered with Current Controlled Trials, under the identifier numbers ISRCTN51688713, ISRCTN40020296.

Coverage and use of insecticide-treated bed nets in households with children aged under five years in Liberia

SETTING

St John's District, Grand Bassa County, Liberia.

OBJECTIVES

In households with children aged <5 years, to examine the coverage and use of long-lasting insecticide-treated bed nets (LLINs), factors associated with non-use and the characteristics and conditions of bed nets.

DESIGN

Cross-sectional study involving interviews with mothers and visual inspection of LLINs.

RESULTS

Of 663 households visited, 492 (74%) had no LLIN and 135 (20%) had one LLIN. Of 171 households with LLINs, these were consistently used by 73 (43%) children. The main reasons for inconsistent use included LLINs being old or damaged, and LLINs generating too much heat for 20-30% of children. Visual inspection of LLINs in 130 households showed that 98% of LLINs were white, 20% were not hung above the child's sleeping place, 30% had holes, 84% were double-bed sized and 82% had been washed in the previous 6 months.

CONCLUSION

Despite reports of 100% LLIN coverage in St John's District, this study showed that only a quarter of households had an LLIN, over half of the children used LLINs inconsistently and the LLINs had several deficiencies. More surveys should be conducted to determine the true coverage of LLINs in Liberia, and measures must be taken to improve the use of LLINs.

The 30 minutes decision-to-delivery interval for ‘urgent’ caesarean sections: An elusive target

The aim of this audit was to evaluate whether the '30 minute decision-to-delivery interval' for 'urgent' caesarean section has shown consistent improvement with repeated audit within this unit. The audit dataset comprised a random sample of all urgent caesarean sections carried out in 2004 classified as 'urgent', i.e. to be completed in 30 min. Nearly one-third of caesarean sections recorded on the delivery suite database as 'urgent' were incorrectly coded. A personal review of case notes was undertaken to ensure accurate data capture. Delivery suite data was analysed by post-hoc modelling of a 'normal' (Gaussian) distribution. The proportion of true 'urgent' caesarean sections completed in 30 min was 50% and some 90% of women were delivered within 40 min. The data were normally distributed, with non-random events, accounted for 25% of the variability. A model for 'urgent' caesarean section, accommodating random and non-random factors closely matched the audit data. We conclude that non-random, institutional, factors reflecting overall delivery suite activity adversely effect the decision-to-delivery interval regardless of the performance of personnel and processes within a delivery suite.

Phase III trial of 5-fluorouracil and leucovorin plus either 3H1 anti-idiotype monoclonal antibody or placebo in patients with advanced colorectal cancer

BACKGROUND

The monoclonal antibody 3H1 mimics the external structure of the carcinoembryonic antigen (CEA). It therefore has the potential, via the anti-idiotypic network, to stimulate immune responses to CEA that may benefit colorectal cancer patients.

PATIENTS AND METHODS

A total of 630 patients with previously untreated metastatic colorectal cancer were randomised in a 2:1 fashion to receive bolus 5-fluorouracil (5-FU) and leucovorin (LV) plus either 3H1 (n = 422) or placebo (n = 208).

RESULTS

The addition of 3H1 to 5-FU and LV did not result in increased toxicity. Survival for the full intent-to-treat population was 14.7 months for the 3H1 arm and 15.2 months for the placebo arm (P = 0.80). Anti-CEA antibody responses were observed in 70% of patients treated with 3H1. Patients with a negative CEA response had a median survival of 8.3 months (95% CI 7.5-11.0) compared with patients with a strong response: median survival not reached (P <0.001).

CONCLUSION

3H1 is safe and effectively induces immune responses to CEA. Addition of 3H1 to 5-FU and LV was not shown to improve overall patient outcomes. However, improved survival in patients developing anti-CEA responses to 3H1 are provocative and should be studied in further clinical trials.

A method for identification of inhibitors of the phosphorylation reactions of bacterial response regulator proteins using (31)P nuclear magnetic resonance spectroscopy

Bacterial response regulators are attractive targets for antibacterial drug development, yet random screening against these targets has failed as yet to identify chemicals that constitute viable leads. Alternative methods to provide leads for drug development based on identification and optimization of low affinity ligands from NMR screens have been described. However, leads from these processes still require verification in a bioassay, which is often problematic if compounds have unfavorable optical and solubility properties. A simple method, based on using NMR to observe the activity of the target, is described. It has the advantages of being able to characterize both low affinity leads and a wider selection of compounds in a structure activity relationships series, without the problems affecting a fluorescence assay. In this example we use (31)P to monitor the turnover of a bacterial response regulator, but the generic approach could be applied to other nuclei and thus a range of biological systems.

Calcium buffering in coronary smooth muscle after chronic occlusion and exercise training

OBJECTIVE

Exercise promotes "sarcoplasmic reticulum (SR) Ca2+ unloading" in porcine coronary smooth muscle, resulting in decreased agonist-induced Ca2+ release. We studied Ca2+ handling in healthy, non-occluded right coronary artery cells from hearts chronically occluded at the circumflex artery.

METHODS

Myoplasmic free Ca2+ (Ca(m)) was assessed with fura-2 in cells from sedentary (n=8) and aerobically exercise-trained (n=6) female Yucatan pigs after 6-month circumflex artery ameroid occlusion (OCC) and in cells from non-occluded, sedentary pigs (SED, n=5). First, Ca influx was induced by 80 mM KCl depolarization (priming step) followed by 5 mM caffeine to elicit maximal Ca2+ release and depletion. The SR was Ca-loaded again by depolarization and then exposed to caffeine after 2- or 11-min recovery to compare SR Ca2+ unloading.

RESULTS

Baseline Ca(m), caffeine-induced peak Ca(m), and depolarization-induced maximum Ca(m) were decreased, and depolarization-induced time-to-half-maximum was increased in OCC vs. SED pigs, suggesting a tonic Ca2+ buffering (lowering) effect of occlusion. Exercise did not alter these effects. SR Ca2+ unloading occurred only in SED, as evidenced by decreased caffeine-induced Ca2+ release after 11 min of recovery, and was inhibited by low extracellular Na+.

CONCLUSIONS

SR Ca2+ unloading can be demonstrated in coronary smooth muscle from sedentary pigs using a novel SR Ca2+ unloading protocol, and Ca2+ unloading partly depends on Na+-Ca2+ exchange activity. Furthermore, SR Ca2+ unloading in cells from non-occluded right coronary arteries of chronically circumflex-occluded pig hearts was not altered by exercise, perhaps due to enhanced tonic Ca2+ extrusion versus cells from normal, sedentary animals.

Endotoxin impairs agonist-stimulated intracellular free calcium (Ca(i)) responses in freshly dispersed aortic endothelial cells

Impairment in endothelial cell intracellular free calcium (Ca(i)) mobilization mechanisms may contribute to decreased nitric oxide (NO) biosynthesis and impaired vasorelaxation responses of endotoxemic guinea pigs to endothelium-dependent vasodilators. We tested this hypothesis using fura-2 microfluorometry to compare agonist-stimulated Ca(i) responses of aortic endothelial cells freshly dispersed from guinea pigs 16 h after intraperitoneal injection of Escherichia coli endotoxin (lipopolysaccharide, LPS; 4 mg/kg) or saline (CON). In the presence of normal extracellular Ca2+ (2 mmol/L), basal (non-stimulated) endothelial Ca(i) (340/380 nm fluorescence ratio, R) was not different between CON and LPS cells (1.1 +/- 0.03 and 1.1 +/- 0.03, respectively). However, exposure to ADP (10 micromol/L) produced a biphasic increase in Ca(i) that was markedly decreased in cells from LPS-treated animals (P < 0.0001). Peak ADP-stimulated Ca(i) responses averaged 2.2 +/- 0.21 in CON cells and 1.5 +/- 0.11 (P < 0.01) in cells dispersed from LPS-treated animals. Exposure to acetylcholine (ACh; 10 micromol/L) produced sustained increases in Ca(i) (R = 1.4 +/- 0.13) in CON cells; however, LPS abolished Ca(i) responses to ACh. Exposure of endothelial cells to substance P (100 nmol/L) produced a biphasic increase in Ca(i) that was not different between groups. In the absence of extracellular Ca2+ (plus 10 micromol/L EGTA), exposure to ADP (10 micromol/L) produced transient increases in Ca(i) (Ca2+ release) that were decreased in cells from LPS-treated versus CON animals. Exposure to ACh in zero Ca2+ (10 micromol/L) produced smaller increases in Ca(i) (peak R = 1.3 +/- 0.12) in CON cells (when compared to ADP); however, Ca(i) responses to ACh remained absent in cells from LPS-treated animals. Re-exposure to Ca2+ produced sustained ACh-induced Ca(i) responses (Ca2+ influx) in cells from CON, but not LPS-treated animals; LPS markedly impaired (P< 0.05) ADP-induced sustained Ca(i) responses. Our data demonstrate that in vivo LPS exposure elicits decreased agonist-stimulated endothelial Ca(i) responses primarily involving impaired Ca2+ influx mechanisms. Known dependence of endothelial agonist-stimulated NO synthesis on Ca(i) suggests that defects in cell Ca2+ mobilization may contribute to LPS-induced impaired NO biosynthesis and decreased endothelium-dependent relaxation.

Separation and characterisation of five polar herbicides using countercurrent chromatography with detection by negative ion electrospray ionisation mass spectrometry

Five polar herbicides were separated and characterised using high-speed analytical countercurrent chromatography (HSACCC) in conjunction with online electrospray mass spectrometry (ESI-MS). The countercurrent chromatography used a standard isocratic biphasic solvent system of hexane/ethyl acetate/methanol/water in reverse phase to effect the separation of these five environmentally important compounds. The chromatograph was coupled to a triple quadrupole mass spectrometer via a standard electrospray liquid chromatography interface that was able to give mass spectra in negative ion mode of each compound. Limits of detection are reported for this series of compounds along with representative negative ion ESI-MS data and calibrations for the separation.

A potent seryl tRNA synthetase inhibitor SB-217452 isolated from a Streptomyces species

A potent inhibitor of seryl tRNA synthetase, designated SB-217452 has been isolated from Streptomyces sp. ATCC 700974. The fermentation, isolation, structure elucidation and some properties are described. SB-217452 showed inhibitory activity against both Staphylococcus aureus and rat seryl tRNA synthetases, with similar IC50 values of approximately 8 nM. The inhibitor is the serine linked nucleoside moiety of the antibiotic albomycin delta2. In contrast to albomycin delta2, SB-217452 showed only very weak antibacterial activity against a limited range of microorganisms. The compound has not been previously reported as a naturally occurring metabolite. In addition to SB-217452, albomycin delta2 Fe3+ complex and the novel Al3+ complex were isolated from the fermentation. These complexes had no seryl tRNA synthetase inhibitory activity.

Mature oligodendrocyte apoptosis precedes IGF-1 production and oligodendrocyte progenitor accumulation and differentiation during demyelination/remyelination

We have documented changes in the oligodendrocyte population during demyelinating insult to the adult CNS. Feeding of cuprizone to adult mice led to apoptotic death of mature oligodendrocytes followed by profound demyelination of the corpus callosum. A regenerative response was initiated even during active demyelination. Oligodendrocyte progenitors have begun to proliferate and then accumulate within the lesion. Many of these cells may have migrated from the sub-ventricular zone and fornix before their accumulation in the demyelinating corpus callosum. The accumulation of differentiating oligodendrocyte progenitors was followed closely by the reappearance of mature oligodendrocytes and remyelination. Interestingly, an increase in IGF-1 mRNA was detected at Week 3 through Week 7, suggesting potential involvement in remyelination. Other factors, however, such as PDGF, NT3, FGF, jagged, and notch remained unchanged. These results suggest that the mature oligodendroglial population depleted by apoptosis is replaced by a newly formed oligodendroglial population derived from progenitors; these accumulate and seem to differentiate during remyelination.

Intra and inter technologist variability in the quality assessment of respiratory tract specimens

The majority of microbiology laboratories have implemented quality improvement procedures such as a Q scoring system to assess the nature of clinical specimens. Our study reviewed the sources and the amount of variation when Q scoring of lower respiratory secretions was performed. In total, 450 slides representing lower respiratory tract secretions were Q scored by three experienced technologists. Total agreement regarding the number of neutrophils, squamous epithelial cells and Q scores was 76%, 57% and 57% respectively. The major factor influencing Q score values was the enumeration of epithelial cells. From our findings, we expect that there is greater variability in Q scoring then is generally acknowledged and there is a substantial degree of subjectivity on part of individual technologists reading gram stains.

Purification and structural determination of SCB1, a gamma-butyrolactone that elicits antibiotic production in Streptomyces coelicolor A3(2)

Early stationary phase culture supernatants of Streptomyces coelicolor A3(2) contained at least four small diffusible signaling molecules that could elicit precocious antibiotic synthesis in the producing strain. The compounds were not detected in exponentially growing cultures. One of these compounds, SCB1, was purified to homogeneity and shown to be a gamma-butyrolactone of structure (2R, 3R,1'R)-2-(1'-hydroxy-6-methylheptyl)-3-hydroxymethylbutanolide . Bioassays of chemically synthesized SCB1, and of its purified stereoisomers, suggest that SCB1 acts in a highly specific manner to elicit the production of both actinorhodin and undecylprodigiosin, the two pigmented antibiotics made by S. coelicolor.

The structure of ribonuclease P protein from Staphylococcus aureus reveals a unique binding site for single-stranded RNA

Ribonuclease P (RNaseP) catalyses the removal of the 5'-leader sequence from pre-tRNA to produce the mature 5' terminus. The prokaryotic RNaseP holoenzyme consists of a catalytic RNA component and a protein subunit (RNaseP protein), which plays an auxiliary but essential role in vivo by binding to the 5'-leader sequence and broadening the substrate specificity of the ribozyme. We determined the three-dimensional high-resolution structure of the RNaseP protein from Staphylococcus aureus (117 amino acid residues) by nuclear magnetic resonance (NMR) spectroscopy in solution. The protein has an alphabeta-fold, similar to the ribonucleoprotein domain. We used small nucleic acid molecules as a model for the 5'-leader sequence to probe the propensity for generic single-stranded RNA binding on the protein surface. The NMR results reveal a contiguous interaction site, which is identical with the previously identified leader sequence binding site in RNaseP holoenzyme. The conserved arginine-rich motif does not bind single-stranded RNA. It is likely that this peptide segment binds selectively to double-stranded sections of P RNA, which are conformationally more rigid. Given the essentiality of RNaseP for the viability of the organism, knowledge of the S. aureus protein structure and insight into its interaction with RNA will help us to develop RNaseP and RNaseP protein as targets for novel antibiotics against this pathogen.

A comparison of the effects of three chelating agents on the root canals of extracted human teeth

The effects of EDTA were compared in vitro with the effects of two other chelating agents: succimer and trientine HCl. Thirty extracted human teeth with single canals were used. Groups of 10 were treated by the three agents and then examined under the scanning electron microscope. The results showed that EDTA widened the dentinal tubules. Trientine HCl also produced widening of the dentinal tubules very similar to EDTA, whereas succimer produced more extensive widening.

Function search in a large transcription factor gene family in Arabidopsis: assessing the potential of reverse genetics to identify insertional mutations in R2R3 MYB genes

More than 92 genes encoding MYB transcription factors of the R2R3 class have been described in Arabidopsis. The functions of a few members of this large gene family have been described, indicating important roles for R2R3 MYB transcription factors in the regulation of secondary metabolism, cell shape, and disease resistance, and in responses to growth regulators and stresses. For the majority of the genes in this family, however, little functional information is available. As the first step to characterizing these genes functionally, the sequences of >90 family members, and the map positions and expression profiles of >60 members, have been determined previously. An important second step in the functional analysis of the MYB family, through a process of reverse genetics that entails the isolation of insertion mutants, is described here. For this purpose, a variety of gene disruption resources has been used, including T-DNA-insertion populations and three distinct populations that harbor transposon insertions. We report the isolation of 47 insertions into 36 distinct MYB genes by screening a total of 73 genes. These defined insertion lines will provide the foundation for subsequent detailed functional analyses for the assignment of specific functions to individual members of the R2R3 MYB gene family.

Redox manipulation using the thiol-oxidizing agent diethyl maleate prevents hepatocellular necrosis and apoptosis in a rodent endotoxemia model

Manipulation of the intracellular redox state has been shown to alter cell activation pathways with resultant changes in cellular function. Previous studies have suggested that thiol oxidation, using the glutathione-depleting agent diethyl maleate (DEM), was able to inhibit endothelial cell activation. We hypothesized that this agent might exert beneficial effects following endotoxemia in the rat, a model in which transendothelial migration of neutrophils is central to the development of hepatocellular injury. Sprague-Dawley rats treated intraperitoneally with lipopolysaccharide (LPS) (200 microg/kg) plus D-galactosamine (GalN) (600 mg/kg) developed hepatocellular necrosis, as evidenced by liver enzyme release and morphological changes. Pretreatment with DEM abrogated this injury in a dose-dependent fashion. Histology revealed reduced neutrophil accumulation in both the parenchyma and sinusoids, consistent with reduced neutrophil sequestration and transendothelial migration. This effect appeared to be related to the ability of DEM to prevent LPS-induced up-regulation of both vascular cell adhesion molecule-1 (VCAM-1) mRNA and intercellular adhesion molecule-1 (ICAM-1) mRNA in the liver, as well as reducing tumor necrosis factor (TNF) mRNA expression. In addition, DEM prevented hepatocyte apoptosis following LPS treatment. The effect was reproduced when TNF was used as an inflammatory stimulus, suggesting a direct protective effect on the hepatocyte. Taken together, these studies show that redox manipulation through thiol oxidation may represent a novel approach to preventing liver necrosis and apoptosis in inflammatory conditions.

Daily times four vinorelbine plus cisplatin in advanced non-small-cell lung cancer: a phase II trial of a novel schedule

PURPOSE

To evaluate the efficacy of a novel multiday schedule of vinorelbine and displatin in patients with advanced NSCLC.

PATIENTS AND METHODS

Thirty patients were enrolled, including 27 patients with stage IV disease, and 11 patients with performance status of 2. They received a maximum of four chemotherapy cycles with cisplatin 20 mg/m2/day and vinorelbine 15 mg/m2/day intravenously (i.v.) for four consecutive days, every three weeks, with prophylactic filgrastim.

RESULTS

Sixteen patients responded (53%, 95% confidence interval (95% CI): 34%-72%), including two complete and fourteen partial confirmed responses. Median survival for all patients was 8.1 months, with actuarial one-year and two-year survival rates of 40% and 15%. Despite prophylactic filgrastim, the delivered vinorelbine dose intensity of 16.8 mg/m2/week caused febrile neutropenia in 48% of patients (16% of cycles), resulting in one treatment-related death. Common nonhematologic toxicities included delayed emesis, asthenia, and constipation.

CONCLUSIONS

This multiday vinorelbine-cisplatin schedule is highly active against advanced NSCLC but results in frequent neutropenic complications. The myelotoxicity and antitumor efficacy of vinorelbine in NSCLC patients may be schedule-dependent.

Delayed treatment with diethyl maleate prevents E-selectin expression in human endothelial cells

BACKGROUND

Polymorphonuclear leukocyte (PMN) infiltration is a significant contributor to tissue damage in many disease states and is known to occur through an orderly set of events. The endothelial cell adhesion molecule E-selectin is involved in the initial rolling of PMNs on the endothelium at sites of inflammation. We have previously shown that the glutathione depleting agent diethyl maleate (DEM) attenuates lung injury in a rodent model of intratracheal LPS stimulation. We hypothesized that DEM might attenuate E-selectin in LPS-treated human umbilical vein endothelial cells as a mechanism underlying this effect. Further, we investigated the role of delayed treatment with DEM on E-selectin expression.

METHODS

Human umbilical vein endothelial cells were treated with DEM (100 to 400 mumol/L) before or after LPS stimulation (1 microgram/mL). Surface expression of E-selectin was examined using a cellular enzyme-linked immunosorbent assay. E-selectin mRNA transcripts were detected by Northern blot analysis. Nuclear factor-kappa B (NF-kappa B) activity was detected with gel shift assays.

RESULTS

DEM significantly inhibited LPS-induced E-selectin surface expression and mRNA levels in a dose-dependent fashion, with complete inhibition at 250 mumol/L, without affecting cell viability. This inhibitory effect was seen even if DEM was added up to 60 minutes after LPS. DEM inhibited NF-kappa B nuclear translocation in a manner that mirrored protein and mRNA levels.

CONCLUSIONS

Delayed treatment with DEM attenuates NF-kappa B nuclear translocation and E-selectin expression in human umbilical vein endothelial cells up to 60 minutes after the onset of LPS stimulation. Thus, DEM may represent an effective intervention for PMN-mediated organ injury even when given after an inflammatory insult.

Pairwise interactions between neuronal alpha7 acetylcholine receptors and alpha-conotoxin ImI

The present work uses alpha-conotoxin ImI (CTx ImI) to probe the neurotransmitter binding site of neuronal alpha7 acetylcholine receptors. We identify key residues in alpha7 that contribute to CTx ImI affinity, and use mutant cycles analysis to identify pairs of residues that stabilize the receptor-conotoxin complex. We first mutated key residues in the seven known loops of alpha7 that converge at the subunit interface to form the ligand binding site. The mutant subunits were expressed in 293 HEK cells, and CTx ImI binding was measured by competition against the initial rate of 125I-alpha-bungarotoxin binding. The results reveal a predominant contribution by Tyr-195 in alpha7, accompanied by smaller contributions by Thr-77, Tyr-93, Asn-111, Gln-117, and Trp-149. Based upon our previous identification of bioactive residues in CTx ImI, we measured binding of receptor and toxin mutations and analyzed the results using thermodynamic mutant cycles. The results reveal a single dominant interaction between Arg-7 of CTx ImI and Tyr-195 of alpha7 that anchors the toxin to the binding site. We also find multiple weak interactions between Asp-5 of CTx ImI and Trp-149, Tyr-151, and Gly-153 of alpha7, and between Trp-10 of CTx ImI and Thr-77 and Asn-111 of alpha7. The overall results establish the orientation of CTx ImI as it bridges the subunit interface and demonstrate close approach of residues on opposing faces of the alpha7 binding site.

Contractile function and myoplasmic free Ca2+ (Cam) in coronary and mesenteric arteries of endotoxemic guinea pigs

Endotoxin-induced vascular hyporesponsiveness could potentially involve alterations of vascular smooth muscle (VSM) myoplasmic free calcium (Ca(m)) mobilization mechanisms. Contractile function and Ca(m)(fura-2 microfluorometry) regulation were evaluated in vitro using coronary (COR) and mesenteric (MES) artery preparations (100-250 microm inner diameter) isolated from guinea pigs 16 h after intraperitoneal (i.p.) injection of either saline (control; CON) or Escherichia coli endotoxin lipopolysaccharide (LPS; 4 mg/kg). Concentration-response relationships to K+ (5-100 mM) were significantly enhanced in both COR and MES arteries isolated from LPS-treated animals. In contrast, contractile responses to prostaglandin F2alpha (PGF2alpha; 1-100 microM) were markedly impaired in COR and MES arteries from LPS-treated animals, while endothelin-1 (ET; 1-100 nM)-mediated contractile responses of these arteries were enhanced at the maximal dose (100 nM). In COR arteries, PGF2alpha (1-100 microM) and ET (1-100 nM) produced biphasic increases in Ca(m) in both CON and LPS groups. No significant differences were observed in either the initial transient peak or secondary sustained Ca(m) responses between groups, suggesting a lack of effect of LPS upon intracellular Ca2+ release or Ca2+ influx mechanisms in COR arteries. Exposure of MES arteries to PGF2alpha and ET produced concentration-dependent increases in Ca(m) in both groups. However, Ca(m) responses of MES arteries lacked initial peak responses, suggesting potential differences in Ca(m) mobilization between COR and MES arteries. Ca(m) responses to K+ (80 mM) and PGF2alpha (1-100 microM) were similar in MES arteries from both groups; however, ET-mediated increases in Ca(m) were significantly blunted in LPS compared with CON MES arteries. Thus, endotoxemia produced differential effects upon depolarization (K4) and receptor (PGF2alpha, ET)-mediated contractile responses in both COR and MES arteries. Reductions in VSM Ca(m) mobilization appear unlikely as a mechanism for LPS-induced impairment of contractile function of COR and MES arteries; other mechanisms (i.e., decreased Ca2+ sensitivity of contractile proteins) may be involved in effects of LPS upon VSM function of COR and MES arteries.

The glutathione depleting agent diethylmaleate prolongs renal allograft survival

INTRODUCTION

Intercellular adhesion molecule 1 (ICAM-1) plays an important role in mediating allograft rejection through its role in cellular trafficking and as an important costimulatory signal mediating T cell activation. We have previously reported that systemic administration of the glutathione (GSH) depleting agent diethylmaleate (DEM) prevents upregulation of ICAM-1 in various inflammatory models, suggesting that this agent may offer benefit in preventing allograft rejection. Thus we evaluated the effects of DEM in a murine model of renal transplantation.

METHODS

Kidneys from C57BL/6 mice were transplanted into MHC incompatible C3H mice. Donors were treated with DEM 1 h prior to sacrifice, whereas recipients received DEM 1 h following transplantation. Animals were followed until the time of death. In separate studies, renal ICAM-1 mRNA expression was evaluated by polymerase chain reaction and the CD4(+) T cell cytokine profile evaluated in a mixed lymphocyte reaction using C3H responder splenocytes and C57BL/6 stimulator cells.

RESULTS

Pretreatment with DEM increased survival from 18.9 +/- 3.6 to 30.6 +/- 10 days (P < 0.05). This increase in survival was associated with a reduction in renal ICAM-1 mRNA expression. Mixed lymphocyte cultures derived from animals pretreated with DEM demonstrated a reduction in the Th1 cytokines IFN-gamma and IL-2 and an increase in the Th2 cytokines IL-4 and IL-10.

CONCLUSION

Administration of DEM with consequent systemic GSH depletion significantly reduces allograft ICAM-1 expression and prolongs graft survival. Although speculative, a shift from a Th1 to a Th2 cytokine response raises the possibility that tolerance induction plays a role in prolonged allograft survival.

Glutathione depletion prevents lipopolysaccharide-induced local skin inflammation

BACKGROUND

We have previously shown that the thiol-oxidizing agent diethyl maleate prevents lipopolysaccharide (LPS)-induced up-regulation of endothelial cell intercellular adhesion molecule-1 (ICAM-1) in vitro.

OBJECTIVE

To determine the effect of glutathione depletion on the development of local skin inflammation in vivo, a model known to be dependent on ICAM-1.

DESIGN

Swiss Webster mice were injected with intradermal LPS (30 micrograms) or isotonic saline solution.

INTERVENTION

Mice were pretreated for 1 hour with intraperitoneal diethyl maleate (6 mmol/kg) or corn oil vehicle.

MAIN OUTCOME MEASURES

Injection sites were harvested after 12 and 24 hours and evaluated for changes in vascular permeability and histological characteristics. To determine the mechanism underlying our findings, we evaluated skin ICAM-1 immunohistochemistry, levels of ICAM-1 protein and messenger RNA (mRNA), and neutrophil CD11b expression at the 24-hour point.

RESULTS

Diethyl maleate significantly decreased the skin permeability index in a dose-dependent fashion at 24 hours but not at 12 hours. Skin histological examination under light microscopy showed a marked LPS-induced neutrophil infiltration at 24 hours, which was inhibited with diethyl maleate pretreatment. Immunohistochemical examination showed that diethyl maleate reduced ICAM-1 expression. In keeping with the hypothesized mechanism, diethyl maleate attenuated the LPS-induced up-regulation of ICAM-1 mRNA by 44%. Diethyl maleate also slightly but insignificantly reduced CD11b expression in vivo.

CONCLUSIONS

Diethyl maleate markedly attenuates LPS-induced dermal inflammation, primarily through a reduction in ICAM-1 protein and mRNA expression. These data suggest that manipulation of the intracellular redox state may have a beneficial role in neutrophil-mediated inflammation.

Executive roundtable II. Talking about quality

In the last issue of Healthcare Executive, we introduced the first in a two-part series on quality in healthcare. The series, which is predicated on a five-hour roundtable discussion among eight healthcare leaders, was moderated by Thomas C. Dolan, Ph.D., FACHE, CAE, ACHE's president and chief executive officer, and jointly sponsored by ACHE and the Bayer Quality Network, an educational forum for sharing innovative and effective continuous quality improvement methods with healthcare executives. In Part I, participants spoke about current issues as they relate to quality. They discussed the reliability of existing quality data and expressed a need for more practical indicators and measurement systems. The consumer mindset was discussed, as leaders debated the value of customer satisfaction surveys and ways to create more realistic consumer expectations. In terms of employers and third parties, participants suggested tailoring quality information and presenting it in a simplified fashion. Finally, leaders emphasized the need for better performance information, as well as the use of outcomes data for both educational and quality improvement purposes. In Part II, the dialogue remains compelling. Participants cover new ground as they talk about the role of accreditors in regulating quality, of governance teams and senior management in creating an organizational culture to support quality, and of physicians in attracting both business partners and patients based on quality. Following is the second in our two-part series.

A phase II evaluation of high dose cisplatin and etoposide in patients with advanced esophageal adenocarcinoma

BACKGROUND

In patients with advanced esophageal adenocarcinoma, the efficacy and palliative role of systemic chemotherapy are not well defined. The primary objective of this Phase II trial was to evaluate the antitumor activity and toxicity of a multiday chemotherapy schedule of high dose cisplatin and etoposide in patients with unresectable or metastatic esophageal adenocarcinoma. A secondary objective was to assess the efficacy of this regimen in palliating dysphagia.

METHODS

Twenty-seven eligible patients with unresectable locoregional or metastatic esophageal adenocarcinoma were treated with cisplatin, 30 mg/m2/day, and etoposide, 60 mg/m2/day, intravenously daily for 5 days, every 3 weeks. After three cycles of chemotherapy, all patients were assessed for response. Patients with responding metastatic disease were given one additional cycle of chemotherapy, and patients with locoregional disease received radiation and concurrent continuous infusion of 5-fluorouracil at 300 mg/m2/day for the duration of radiation therapy. Patients were questioned about dysphagia symptoms initially and then weekly during chemotherapy.

RESULTS

The major toxicities included myelosuppression, nausea and vomiting, and peripheral sensory neuropathy, with one treatment-related death. Major responses were observed in 13 patients (48%; 95% confidence intervals, 36-74%), including 5 complete and 8 partial responses. Dysphagia relief occurred in 89% of 18 symptomatic patients within a median time of 16 days. The median survival duration for all patients was 9.8 months, and the actuarial 3-year survival rate was 22%.

CONCLUSIONS

Multiday chemotherapy with high dose cisplatin and etoposide is active in patients with advanced esophageal adenocarcinoma. Toxicities associated with this regimen are substantial but manageable.

Photodynamic therapy for esophageal malignancy: a prospective twelve-year study

BACKGROUND

We wanted to determine factors affecting survival rates of benefits to, and complications in patients with esophageal cancer treated with photodynamic therapy.

METHODS

From 1982 to January 1994, we used photodynamic therapy to treat 77 patients with esophageal carcinoma and evaluated survival to July 1994. All patients had failed, refused, or were ineligible for surgical intervention, ionizing radiation therapy, or chemotherapy.

RESULTS

The only significant variable affecting survival was clinical stage. Median survival after photodynamic therapy was as follows: all patients, 6.3 months (mean survival, 9.2 months); stage I, not reached; stage II, 12 months; stage III, 6.2 months; and stage IV, 3.5 months. For stages III and IV, a Karnofsky performance status of 70 or higher had a significant effect. For stage III, the median survival was 6.3 months when the Karnofsky performance status was equal to or greater than 70 and 3.5 months when it was less than 70. For stage IV, the median survival was 5.5 months when the Karnofsky performance status was equal to or greater than 70 and 2.5 months when it was lower than 70. Seven stage I patients with no treatment prior to photodynamic therapy had an estimated 5-year survival rate of 62%. Three patients with stage I invasive adenocarcinoma and Barrett's mucosa diagnosed when they underwent endoscopy for dysphagia were alive with no evidence of disease 17, 44, and 59 months after photodynamic therapy.

CONCLUSIONS

Photodynamic therapy for esophageal carcinoma caused minimal complications and no procedure-related deaths. Photodynamic therapy can be considered an alternative treatment for patients with Barrett's esophagus with severe dysplasia or patients with stage I carcinoma who are under consideration for operation but are high surgical risks. The length of palliation for patients having "noncurative" treatment was equal to or better than that reported historically for most other treatment regimens.

Evaluation of coronal microleakage after endodontic treatment

A new method is suggested for placing a coronal seal in the orifice of the root canal right after root canal therapy. Root canal therapy was done on 94 extracted human maxillary centrals. Three mm of the coronal gutta-percha was replaced by either Cavit, TERM, or amalgam with cavity varnish. After thermocycling and 2 wk of immersion in dye, the amount of dye penetration was measured. The results showed that amalgam with two coats of cavity varnish sealed significantly better than Cavit and TERM. However, Cavit and TERM were still significantly better than a positive control group.

Endotoxin-induced myocardial dysfunction: is there a role for nitric oxide?

Nitric oxide has been implicated in the regulation of cardiac contractile function as well as the depressed myocardial contractility associated with sepsis and endotoxemia. We examined the effects of nitric oxide synthase (NOS) inhibitors and a nitric oxide generator on contractile responses of left atrial preparations and ventricular myocytes isolated from endotoxemic guinea pigs, which exhibit depressed myocardial contractile function. The NOS inhibitor L-NAME had no effect on contractile tension developed by control atria or atria isolated from guinea pigs 4 or 16 h after an intraperitoneal injection of endotoxin. Similarly, contraction of ventricular myocytes isolated from control or endotoxemic guinea pigs (4 h after endotoxin injection) was unchanged by exposure to several NOS inhibitors. In addition, neither Ca(2+)-dependent nor Ca(2+)-independent ventricular NOS activity was affected by endotoxemia. These data suggest that nitric oxide alone is not responsible for the cardiac contractile dysfunction of endotoxemic guinea pigs.

Release of EDRF and NO in ex vivo perfused aorta: inhibition by in vivo E. coli endotoxemia

Previous studies have yielded contradictory results about interrelations between endotoxin and endothelium-derived relaxing factor (EDRF). We tested the hypothesis that in vivo endotoxemia inhibits basal and/or agonist-mediated release of EDRF and nitric oxide (NO). EDRF bioactivity, NO production, and NO synthase (NOS) activity were measured in aorta from guinea pigs following 16 h of Escherichia coli endotoxemia (4 mg/kg endotoxin i.p.). Endothelium-dependent relaxation of aortic rings was studied under standard isometric conditions. Endotoxemia resulted in an 89% reduction in basal EDRF bioactivity and a 62% reduction in basal NO production in perfused aorta. EDRF bioactivity and NO production in response to the receptor-dependent agonists acetylcholine and ADP were significantly reduced in perfused aorta from endotoxemic animals. In contrast, endotoxin did not significantly inhibit EDRF bioactivity and NO production by the receptor-independent agonist A-23187. Aortic rings from endotoxemic animals likewise showed decreased vasodilator responses to acetylcholine and ADP but not to A-23187. Inducible (Ca2+ independent) NOS activity was not significantly different in control and endotoxin-treated animals. These findings indicate that prolonged endotoxemia resulted in diminution of release of EDRF, consistent with the interpretation that endotoxemia decreases basal and agonist-stimulated EDRF bioactivity and NO production with loss of endothelium-dependent vasodilator reserves during gram-negative sepsis.

Longitudinal assessment of blood pressures in black and white children

The prevalence of hypertension is greater for blacks than whites. Whether black children have higher blood pressure than white children is less clear. We investigated this issue through a prospective longitudinal assessment of blood pressure in 345 white children and 164 black children. Each child had his or her blood pressure measured every 6 months for 2 to 5.5 years. The means for systolic and diastolic blood pressures for each individual were calculated, and the rate of change in blood pressure over time for each subject was estimated. The mean blood pressure and the mean rate were compared between gender-specific black and white groups. For both boys and girls, the mean systolic blood pressure was 2 mm Hg higher in black children than white children (P = .0008). Boys had a higher systolic blood pressure than girls (P = .0048). The mean diastolic blood pressure was 1.5 mm Hg higher in black children than in white children (P = .0270); no significant gender difference in diastolic blood pressure was observed. Age, weight, height, and body mass index were highly correlated with blood pressure. When accounting for these variables, for girls the racial difference in systolic blood pressure remained significant, whereas the difference in diastolic blood pressure in boys and girls was no longer significant. The rate of increase in blood pressure over time was significantly greater in blacks than whites: for systolic blood pressure, P = .0002, and for diastolic blood pressure, P = .009.(ABSTRACT TRUNCATED AT 250 WORDS)

Mild cervical dyskaryosis: safety of cytological surveillance

How best to manage women who are found on cervical screening to have mild dyskaryosis remains controversial. Cytological surveillance misses some lesions picked up by colposcopy, but colposcopy is emotionally traumatic for women, the majority of whom will have a normal result. To determine what proportion of lesions are missed by cytological surveillance, and whether any abnormalities persist after colposcopy, we studied, by means of colposcopy and biopsy, the prevalence of cervical intraepithelial neoplasia (CIN) and subclinical human papillomavirus infection (HPVI) in two groups of patients who had had a first smear showing mild dyskaryosis at least 24 months earlier. One group was recruited from a centre practising cytological surveillance, with colposcopy for patients showing persistent or progressive cytological abnormality. The other group all had early colposcopy and treatment. Of 214 patients recruited into the cytological surveillance group, 70 (33%) had been referred for colposcopy within 24 months. Colposcopy of the remaining 144 (after a mean interval of 27 months from presentation) revealed that 54 (38%) were disease free, 64 (44%) had HPVI/CIN1, 8 (6%) had CIN2, and 18 (12%) had CIN3. A smear at that time identified 12 of the 18 (67%) with CIN3 as needing close cytological follow-up (1 patient) or prompt referral for colposcopy (11 patients). 137 women in the early colposcopy group attended for the study colposcopy (after a mean interval of 32 months from presentation). 37% were found to have some abnormality persisting after an earlier colposcopy, but none had CIN3. Cytological surveillance of mild dyskaryosis resulted in a 12% risk of patients having a small CIN3 lesion after 2 years, but this risk was reduced to 4% by the addition of a third repeat smear 12 months after the second. With such a policy only about a third of women would require colposcopy, and the risk of missing serious underlying precancerous changes would be low.

Adrenal androgen excretion during adrenarche. Relation to race and blood pressure

We have previously shown that black children have higher blood pressures than white children. In the present study, we examined whether a possible racial difference in adrenal androgen production during adrenarche might contribute to the racial disparity in blood pressure. Adrenal androgen production was estimated from urinary excretion of adrenal androgen metabolites that showed cross-reactivity with antisera to dehydroepiandrosterone sulfate (DHEA-S). Urine samples were collected overnight in 798 children, one third of whom were black. Analyses were performed for two different age groups, less than 10 years and 10 years or more of age. In children less than 10 years of age, adrenal androgen excretion rates were 17% higher in blacks than in whites (p = 0.0099); adrenal androgen excretion rates tended to be higher in older black children as well, but differences here were not statistically significant. Adrenal androgen excretion rates were positively correlated with diastolic blood pressure in the older age group only (p = 0.014). However, when the relation of race to blood pressure was examined along with adrenal androgen excretion adjusted for age, sex, and weight, race remained an independent contributor to the level of blood pressure, suggesting that a difference in adrenal androgens could not explain the racial differences in blood pressure. In summary, black children produced more adrenal androgen, but this did not explain their higher blood pressures. In older children, where adrenal androgen excretion rates were higher, diastolic blood pressure and adrenal androgen excretion were positively related, suggesting that adrenal androgens participate in establishing the level of blood pressure in young people.

Oral health status of a federal prison population

The purpose of this study was to describe the prevalence of decayed, missing, and filled teeth among federal male prisoners (aged 21-75) in the US Penitentiary. Leavenworth, Kansas, and to assess the impact of age, race, number of years incarcerated, and number of visits to the prison dentist on these parameters of oral health. Inmates (n = 191) were randomly selected and represented 16.4 percent of the prison population (N = 1,161). Two calibrated examiners collected caries and tooth loss data using NIDR criteria. No radiographs were taken. Results showed a mean DMFT of 12.9 for inmates aged 20-34, 16.4 for inmates aged 35- 44, and 22.1 for inmates aged 45 and older. Whites had significantly fewer decayed teeth (P less than .05) than black inmates for ages 20-34. The number of missing teeth increased significantly (P less than .01) with inmate age. Proportion edentulous (both arches) was 5.2 percent for ages 35 to 44, 17.3 percent for ages 45-54, and 45.5 percent for ages 55 to 75. Cross tabulations and chi-square analyses showed that inmates incarcerated less than two years had a significantly (P less than .001) lower utilization rate of dental services, and that inmates who made greater use of available dental services had fewer decayed teeth than those with lower utilization rates.

Racial differences in aldosterone excretion and plasma aldosterone concentrations in children

Blacks are more likely to have hypertension, have lower levels of plasma renin activity, and typically consume less potassium than whites. Whether blacks and whites secrete different amounts of aldosterone is less clear. We estimated aldosterone secretion indirectly in 715 children, 249 of whom were black, by measuring their nocturnal rates of urinary excretion of aldosterone. Dietary sodium and potassium intakes were estimated from their excretion rates. The mean (+/- SE) aldosterone-excretion rate was lower in the black children than in the white children (0.045 +/- 0.003 vs. 0.078 +/- 0.004 nmol per micromole of creatinine per kilogram of body weight; P less than 0.001). The potassium-excretion rate was also lower in the black children than in the white children (0.13 +/- 0.01 vs. 0.18 +/- 0.01 mmol per micromole of creatinine per kilogram; P less than 0.001). Aldosterone excretion was highly correlated with potassium excretion (P less than 0.001), but the lower aldosterone-excretion rate in blacks was explained only in part by their lower dietary intake of potassium. Systolic blood pressure was higher in black children (P less than 0.001), as was diastolic pressure (P = 0.037). In a second study of 99 children, the plasma aldosterone level was found to be significantly lower in black children than in white children (230 +/- 30 vs. 400 +/- 30 pmol per liter; P less than 0.001). Plasma renin activity and plasma cortisol levels were the same in both groups. In summary, we found that black children secrete about 40 percent less aldosterone than white children. The role of the lower aldosterone-secretion rate in the genesis of the higher blood pressures observed in black children is not known.

A review of applications of MRI in soft tissue and bone tumors

Due to excellent soft tissue contrast and multiplanar imaging capability, MRI is assuming a major role in recognition, staging, and treatment planning of soft tissue and bone tumors. Direct sagittal, coronal, and axial images permit assessment of intraosseous and extraosseous extension of tumors and their relationship to the joints and neurovascular structures, and detection of "skip" lesions. MRI allows improved detection of recurrent tumors in the presence of non-ferromagnetic metallic implants as compared to CT. In the evaluation of soft tissue tumors, MRI is more sensitive than CT and allows differentiation among fat, muscle, tendon, bone, and vascular structures based on signal characteristics. Over a period of 18 months, 100 soft tissue masses and bone tumors were evaluated using MRI. Spin echo sequences with T1 and T2 weighted images were most valuable in differentiating normal and abnormal tissues. Calculated comparative measurements of relaxation times showed no reliable difference between benign and malignant tumors.

The management of primary lymphoma of bone

From October 1962 through April 1982, 21 patients with the diagnosis of primary lymphoma of bone (18 monostotic, stages IE and IIE; 3 polyostotic) were treated with curative intent. A combination of chemotherapy and radiation therapy was used in 11 patients, local treatment alone in 9 patients, and chemotherapy alone in one patient. Overall 5-year survival for the patients treated with curative intent was 56%. Standard work-up has changed over the 20-year study period. Five-year survival for the subset of eight stage I and II patients with full pretherapy staging was 83%. Prognosis was significantly correlated with extent of pretherapy staging. Treatment parameters that also seemed to predict outcome were the aggressiveness of chemotherapy and the use of irradiation or surgery for local-regional disease; the only local failure occurred in the patient who received chemotherapy alone. Complications of radiation therapy alone and in combination with chemotherapy are discussed and correlated with irradiation dose. Radiation therapy techniques are described, and a management approach is recommended.