Early sepsis in Australia and New Zealand: A point-prevalence study of haemodynamic resuscitation practices

OBJECTIVE

Optimal resuscitation of sepsis-induced hypotension is uncertain, particularly the role of restrictive fluid strategies, leading to variability in usual practice. The objective of this study is to understand resuscitation practices in patients presenting to ED with early sepsis.

METHODS

Design, participants and setting: Prospective, observational, multicentre, single-day, point-prevalence study enrolling adult patients present in 51 Australian and New Zealand ICUs at 10.00 hours, 8 June 2021.

MAIN OUTCOME MEASURES

Site-level data on sepsis policies and patient-level demographic data, presence of sepsis and fluid and vasopressor administration in the first 24 h post-ED presentation.

RESULTS

A total of 722 patients were enrolled. ED was the ICU admission source for 222 of 722 patients (31.2%) and 78 of 222 patients (35%) met the criteria for sepsis within 24 h of ED presentation. Median age of the sepsis cohort was 61 (48-72) years, 58% were male and respiratory infection was the commonest cause (53.8%). The sepsis cohort had a higher severity of illness than the non-sepsis cohort (144/222 patients) and chronic immunocompromise was more common. Of 78 sepsis patients, 55 (71%) received ≥1 fluid boluses with 500 and 1000 mL boluses equally common (both 49%). In the first 24 h, 2335 (1409-3125) mL (25.3 [13.2-42.9] mL/kg) was administered. Vasopressors were administered in 53 of 78 patients (68%) and for 25 patients (47%) administration was peripheral.

CONCLUSIONS

ICU patients presenting to the ED with sepsis receive less fluids than current international recommendations and peripheral vasopressor administration is common. This finding supports the conduct of clinical trials evaluating optimal fluid dose and vasopressor timing for early sepsis-induced hypotension.

Study protocol for TARGET protein: The effect of augmented administration of enteral protein to critically ill adults on clinical outcomes: A cluster randomised, cross-sectional, double cross-over, clinical trial

Background

It is unknown whether increasing dietary protein to 1.2-2.0 g/kg/day as recommended in international guidelines compared to current practice improves outcomes in intensive care unit (ICU) patients. The TARGET Protein trial will evaluate this.

Objective

To describe the study protocol for the TARGET Protein trial.

Design setting and participants

TARGET Protein is a cluster randomised, cross-sectional, double cross-over, pragmatic clinical trial undertaken in eight ICUs in Australia and New Zealand. Each ICU will be randomised to use one of two trial enteral formulae for three months before crossing over to the other formula, which is then repeated, with enrolment continuing at each ICU for 12 months. All patients aged ≥16 years in their index ICU admission commencing enteral nutrition will be eligible for inclusion. Eligible patients will receive the trial enteral formula to which their ICU is allocated. The two trial enteral formulae are isocaloric with a difference in protein dose: intervention 100g/1000 ml and comparator 63g/1000 ml. Staggered recruitment commenced in May 2022.

Main outcomes measures

The primary outcome is days free of the index hospital and alive at day 90. Secondary outcomes include days free of the index hospital at day 90 in survivors, alive at day 90, duration of invasive ventilation, ICU and hospital length of stay, incidence of tracheostomy insertion, renal replacement therapy, and discharge destination.

Conclusion

TARGET Protein aims to determine whether augmented enteral protein delivery reduces days free of the index hospital and alive at day 90.

Trial registration

Australian New Zealand Clinical Trials Registry (ACTRN12621001484831).

Protein delivery in mechanically ventilated adults in Australia and New Zealand: current practice

Objective: To quantify current protein prescription and delivery in critically ill adults in Australia and New Zealand and compare it with international guidelines. Design: Prospective, multicentre, observational study. Setting: Five intensive care units (ICUs) across Australia and New Zealand. Participants: Mechanically ventilated adults who were anticipated to receive enteral nutrition for ≥ 24 hours. Main outcome measures: Baseline demographic and nutrition data in ICU, including assessment of requirements, prescription and delivery of enteral nutrition, parenteral nutrition and protein supplementation, were collected. The primary outcome was enteral nutrition protein delivery (g/kg ideal body weight [IBW] per day). Data are reported as mean ± standard deviation or n (%). Results: 120 patients were studied (sex, 60% male; mean age, 59 ± 16 years; mean admission APACHE II score, 20 ± 8). Enteral nutrition was delivered on 88%, parenteral nutrition on 6.8%, and protein supplements on 0.3% of 1156 study days. For the 73% (88/120) of patients who had a nutritional assessment, the mean estimated protein requirements were 99 ± 22 g/day (1.46 ± 0.55 g/kg IBW per day). The mean daily protein delivery was 54 ± 23 g (0.85 ± 0.35 g/kg IBW per day) from enteral nutrition and 56 ± 23 g (0.88 ± 0.35 g/kg IBW per day) from all sources (enteral nutrition, parenteral nutrition, protein supplements). Protein delivery was ≥ 1.2 g/kg IBW per day on 29% of the total study days per patient. Conclusions: Protein delivery as a part of current usual care to critically ill adults in Australia and New Zealand remains below that recommended in international guidelines.

The cost-effectiveness of early goal-directed therapy: an economic evaluation alongside the ARISE trial

Objective: To determine the cost-effectiveness of early goal-directed therapy (EGDT) for patients with early septic shock. Design: Within-trial cost-effectiveness evaluation. Setting: Nineteen hospitals in Australia and New Zealand. Participants and interventions: Patients with early septic shock enrolled in the Australasian Resuscitation in Sepsis Evaluation (ARISE) trial were randomly assigned to EGDT versus usual care. A subgroup of patients participated in a nested economic evaluation study in which detailed resource use data were collected until 12 months after randomisation. Outcome measures: Clinical outcomes included lives saved, life-years gained and quality-adjusted life-years (QALYs), with mortality collected until 12 months and health-related quality of life assessed at baseline, 6 and 12 months using the 3-level EuroQol five dimensions questionnaire (EQ-5D-3L). Economic outcomes included health care resource use, costs and cost-effectiveness from the Australian health care payer perspective. Results: A total of 205 patients (100 EGDT, 105 usual care) participated in the nested economic evaluation study, of which 203 had complete resource use data. Unadjusted mean health care costs to 12 months were $67 223 (standard deviation [SD], $72 397) in the EGDT group and $54 179 (SD, $61 980) in the usual care group, with a mean difference of $13 044 (95% CI, -$5791 to $31 878). There was no difference between groups with regards to lives saved (EGDT, 69.4% v usual care, 68.6%; P = 1.0), life-years gained (mean EGDT, 0.746 [SD, 0.406] v usual care, 0.725 [SD, 0.417]; P = 0.72) or QALYs (mean EGDT, 0.318 [SD, 0.291] v usual care, 0.367 [SD, 0.295]; P = 0.24). EGDT was dominated (higher costs, lower effectiveness) by usual care in 80.4% of bootstrap replications. For a willingness-to-pay threshold of $50 000 per QALY, the probability of EGDT being cost-effective was only 6.4%. Conclusions: In patients presenting to the emergency department with early septic shock, EGDT compared with usual care was not cost-effective. Clinical trial registration:ClinicalTrials.gov number NCT00975793.

Use of a High-Protein Enteral Nutrition Formula to Increase Protein Delivery to Critically Ill Patients: A Randomized, Blinded, Parallel-Group, Feasibility Trial

BACKGROUND

International guidelines recommend critically ill adults receive more protein than most receive. We aimed to establish the feasibility of a trial to evaluate whether feeding protein to international recommendations would improve outcomes, in which 1 group received protein doses representative of international guideline recommendations (high protein) and the other received doses similar to usual practice.

METHODS

We conducted a prospective, randomized, blinded, parallel-group, feasibility trial across 6 intensive care units. Critically ill, mechanically ventilated adults expected to receive enteral nutrition (EN) for ≥2 days were randomized to receive EN containing 63 or 100 g/L protein for ≤28 days. Data are mean (SD) or median (interquartile range).

RESULTS

The recruitment rate was 0.35 (0.13) patients per day, with 120 patients randomized and data available for 116 (n = 58 per group). Protein delivery was greater in the high-protein group (1.52 [0.52] vs 0.99 [0.27] grams of protein per kilogram of ideal body weight per day; difference, 0.53 [95% CI, 0.38-0.69] g/kg/d protein), with no difference in energy delivery (difference, -26 [95% CI, -190 to 137] kcal/kg/d). There were no between-group differences in the duration of feeding (8.7 [7.3] vs 8.1 [6.3] days), and blinding of the intervention was confirmed. There were no differences in clinical outcomes, including 90-day mortality (14/55 [26%] vs 15/56 [27%]; risk difference, -1.3% [95% CI, -17.7% to 15.0%]).

CONCLUSION

Conducting a multicenter blinded trial is feasible to compare protein delivery at international guideline-recommended levels with doses similar to usual care during critical illness.

Energy-dense vs routine enteral nutrition in New Zealand Europeans, Māori, and Pacific Peoples who are critically ill

AIMS

To evaluate the effect of energy-dense vs routine enteral nutrition on day-90 mortality by ethnic group in critically ill adults.

METHODS

Pre-planned subgroup analysis of the 1,257 New Zealanders in a 4,000-participant randomised trial comparing energy-dense enteral nutrition (1.5kcal/mL) with routine enteral nutrition (1kcal/mL) in mechanically ventilated intensive care unit (ICU) patients. The primary purpose of this analysis was to evaluate responses to study treatment by ethnic group (European, Māori, and Pacific Peoples) using ethnicity data recorded in the clinical records. The secondary purpose was to compare the characteristics and outcomes of patients by ethnic group. The primary outcome was day-90 mortality.

RESULTS

Among 1,138 patients included in the primary outcome analysis, 165 of 569 (29.0%) assigned to energy-dense nutrition and 156 of 569 patients (27.4%) assigned to routine nutrition died by day 90 (odds ratio; 1.06; 95% CI, 0.92-1.22). There was no statistically significant interaction between treatment allocation and ethnicity with respect to day-90 mortality. Day-90 mortality rates did not vary statistically significantly by ethnic group.

CONCLUSIONS

Among mechanically ventilated adults in New Zealand ICUs, the effect on day-90 mortality of energy-dense vs routine enteral nutrition did not vary by ethnicity.

Comparison of ultrasound-guided transmuscular quadratus lumborum block catheter technique with surgical pre-peritoneal catheter for postoperative analgesia in abdominal surgery: a randomised controlled trial

Following abdominal surgery, the provision of postoperative analgesia with local anaesthetic infusion through both transmuscular quadratus lumborum block and pre-peritoneal catheter have been described. This study compared these two methods of postoperative analgesia following laparotomy. Eighty-two patients 18-85 years of age scheduled to undergo elective surgery were randomly allocated to receive either transmuscular quadratus lumborum block or pre-peritoneal catheter block. In the transmuscular quadratus lumborum group, an 18-gauge Tuohy needle was passed through the quadratus lumborum muscle under ultrasound guidance to reach its anterior aspect. A 20-ml bolus of ropivacaine 0.375% was administered and catheters placed bilaterally. In the pre-peritoneal catheter group, 20 ml of ropivacaine 0.375% was infiltrated at each of three subcutaneous sub-fascial levels, and pre-peritoneal plane catheters were placed bilaterally. Both groups received an infusion of ropivacaine 0.2% at 5 ml.h^-1 , continued up to 48 h along with a multimodal analgesic regime that included regular paracetamol and patient-controlled analgesia with fentanyl. The primary end-point was postoperative pain score on coughing, assessed using a numerical rating score (0-10). Secondary outcomes were pain score at rest, fentanyl usage until 48 h post-operation, satisfaction scores and costs. There was no treatment difference between the two groups for pain score on coughing (p = 0.24). In the transmuscular quadratus lumborum group, there was a reduction in numerical rating score at rest (p = 0.036) and satisfaction scores on days 1 and 30 (p = 0.004, p = 0.006, respectively), but fentanyl usage was similar. In the transmuscular quadratus lumborum group, the highest and lowest blocks observed in the recovery area were T4 and L1, respectively. The transmuscular quadratus lumborum technique cost 574.64 Australian dollars more per patient than the pre-peritoneal catheter technique.

Assessment of Outcome over a 10-year Period of Patients Admitted to a Multidisciplinary Adult Intensive Care Unit with Haematological and Solid Tumours

The risk factors for time to mortality, censored at 30 days, of patients admitted to an adult teaching hospital ICU with haematological and solid malignancies were assessed in a retrospective cohort study.

Patients, demographics and daily ICU patient data, from admission to day 8, were identified from a prospective computerized database and casenote review in consecutive admissions to ICU with haematological and solid tumours over a 10-year period (1989–99). The cohort, 108 ICU admissions in 89 patients was of mean age (±SD) 55±14 years; 43% were female. Patient diagnoses were leukaemia (35%), lymphoma (38%) and solid tumours (27%). Median time from hospital to ICU admission was five days (range 0–67). On ICU admission, 50% had septic shock and first day APACHE II score was 28±9. Forty-six per cent of patients were ventilated. ICU and 30-day mortality were 39% and 54% respectively. Multivariate Cox model predictors (P<0.05), using only ICU admission day data were: Charlson comorbidity index (CCI), time to ICU admission (days) and mechanical ventilation. For daily data (admission through day 8), predictors were: cohort effect (2nd vs 1st five-year period); CCI; time to ICU admission (days); APACHE II score and mechanical ventilation.

Outcomes were considered appropriate for severity of illness and demonstrated improvement over time. Ventilation was an independent outcome determinant. Controlling for other factors, mortality has improved over time (1st vs 2nd five year period). Analysis restricted to admission data alone may be insensitive to particular covariate effects.

Modelling Thirty-day Mortality in the Acute Respiratory Distress Syndrome (ARDS) in an Adult ICU

Variables predicting thirty-day outcome from Acute Respiratory Distress Syndrome (ARDS) were analysed using Cox regression structured for time-varying covariates. Over a three-year period, 1996–1998, consecutive patients with ARDS (bilateral chest X-ray opacities, PaO2/FiO2 ratio of <200 and an acute precipitating event) were identified using a prospective computerized data base in a university teaching hospital ICU.

The cohort, 106 mechanically ventilated patients, was of mean (SD) age 63.5 (15.5) years and 37% were female. Primary lung injury occurred in 45% and 24% were postoperative. ICU-admission day APACHE II score was 25 (8); ARDS onset time from ICU admission was 1 day (median: range 0-16) and 30 day mortality was 41% (95% CI: 33%-51%). At ARDS onset, PaO2/FiO2 ratio was 92 (31), 81% had four-quadrant chest X-ray opacification and lung injury score was 2.75 (0.45). Average mechanical ventilator tidal volume was 10.3 ml/ predicted kg weight. Cox model mortality predictors (hazard ratio, 95% CI) were: APACHE II score, 1.15 (1.09-1.21); ARDS lag time (days), 0.72 (0.58-0.89); direct versus indirect injury, 2.89 (1.45-5.76); PaO2/FiO2 ratio, 0.98 (0.97-0.99); operative versus non-operative category, 0.24 (0.09-0.63). Time-varying effects were evident for PaO2/FiO2 ratio, operative versus non-operative category and ventilator tidal volume assessed as a categorical predictor with a cut-point of 8 ml/kg predicted weight (mean tidal volumes, 7.1 (1.9) vs 10.7 (1.6) ml/kg predicted weight). Thirty-day survival was improved for patients ventilated with lower tidal volumes.

Survival predictors in ARDS were multifactorial and related to patient-injury-time interaction and level of mechanical ventilator tidal volume.

Hydrochemical profiles in urban groundwater systems: New insights into contaminant sources and pathways in the subsurface from legacy and emerging contaminants

It has long been known that groundwaters beneath urban areas carry a fingerprint from urban activities but finding a consistent tracer for anthropogenic influence has proved elusive. The varied sources of urban contaminants means that a single consistent and inexpensive means of tracing the fate of urban contaminants is not generally possible and multiple tracers are often required to understand the contaminant sources and pathways in these complex systems. This study has utilized a combination of micro-organic (MO) contaminants and inorganic hydrochemistry to trace recharge pathways and quantify the variability of groundwater quality in multi-level piezometers in the city of Doncaster, UK. A total of 23 MOs were detected during this study, with more compounds consistently detected during higher groundwater table conditions highlighting the importance of sampling under different hydrological conditions. Four of the compounds detected are EU Water Framework Directive priority substances: atrazine, simazine, naphthalene and DEHP, with a maximum concentration of 0.18, 0.03, 0.2, 16μg/l respectively. Our study shows that the burden of the banned pesticide atrazine persists in the Sherwood Sandstone and is detected at two of the three study sites. Emerging contaminants are seen throughout the borehole profiles and provide insights into transient pathways for contaminant migration in the sub-surface. Long term changes in inorganic hydrochemistry show possible changes in contaminant input or the dissolution of minerals. Nitrate was detected above 50mg/l but on the whole nitrate concentrations have declined in the intervening years either due to a reduction of nitrate application at the surface or a migration of peak nitrate concentrations laterally or to greater depth. This study shows that multiple tracers together with multi-level piezometers can give a better resolution of contaminant pathways and variable flow regimes within the relatively uncomplicated aquifer of the Sherwood Sandstone compared with single long screened wells.

Temperature effects on hatching and viability of Juvenile Gill Lice, Salmincola californiensis

Salmonids of the genus Oncorhynchus, distributed throughout the Pacific Rim, can be infected by the gill lice species Salmincola californiensis (Dana, 1852), which makes them one of the most broadly distributed gill lice species. Despite their broad distribution and valuable obligate salmonid hosts, relatively little is known about S. californiensis. We evaluated effects of temperature on timing of S. californiensis hatching and survival of copepodids, and provide information on brood size and variability. Our results suggest that temperature was a primary driver of timing of S. californiensis hatching and post-hatching survival. Prior to this study, the free-swimming stage of S. californiensis was reported to survive approximately 2 days without a suitable host. We observed active copepodids 13 days after hatch with some individuals from most (>90%) viable egg sacs at all temperature treatments surviving ≥5 days. Our findings indicate that warmer temperatures could increase development rates of gill lice at certain life stages, potentially increasing fecundity. This information coupled with predictions that warmer water temperatures could intensify crowding of coldwater fishes, stress, and parasite transmission suggests that climate change could exacerbate negative effects of S. californiensis on ecologically and economically important salmonids.

Using UHF proximity loggers to quantify male-female interactions: a scoping study of estrous activity in cattle

Reproductive efficiency is an important determinant of profitable cattle breeding systems and the success of assisted reproductive techniques (ART) in wildlife conservation programs. Methods of estrous detection used in intensive beef and dairy cattle systems lack accuracy and remain the single biggest issue for improvement of reproductive rates and such methods are not practical for either large-scale extensive beef cattle enterprises or free-living mammalian species. Recent developments in UHF (ultra high frequency) proximity logger telemetry devices have been used to provide a continuous pair-wise measure of associations between individual animals for both livestock and wildlife. The objective of this study was to explore the potential of using UHF telemetry to identify the reproductive cycle phenotype in terms of intensity and duration of estrus. The study was conducted using Belmont Red (interbred Africander Brahman Hereford-Shorthorn) cattle grazing irrigated pasture on Belmont Research Station, northeastern Australia. The cow-bull associations from three groups of cows each with one bull were recorded over a 7-week breeding season and the stage of estrus was identified using ultrasonography. Telemetry data from bull and cows, collected over 4 8-day logger deployments, were log transformed and analyzed by ANOVA. Both the number and duration of bull-cow affiliations were significantly (P<0.001) greater in estrous cows compared to anestrus cows. These results support the development of the UHF technology as a hands-off and noninvasive means of gathering socio-sexual information on both wildlife and livestock for reproductive management.

Functional genomics of acclimation and adaptation in response to thermal stress in Daphnia

Background

Gene expression regulation is one of the fundamental mechanisms of phenotypic plasticity and is expected to respond to selection in conditions favoring phenotypic response. The observation that many organisms increase their stress tolerance after acclimation to moderate levels of stress is an example of plasticity which has been long hypothesized to be based on adaptive changes in gene expression. We report genome-wide patterns of gene expression in two heat-tolerant and two heat-sensitive parthenogenetic clones of the zooplankton crustacean Daphnia pulex exposed for three generations to either optimal (18°C) or substressful (28°C) temperature.

Results

A large number of genes responded to temperature and many demonstrated a significant genotype-by-environment (GxE) interaction. Among genes with a significant GxE there were approximately equally frequent instances of canalization, i.e. stronger plasticity in heat-sensitive than in heat-tolerant clones, and of enhancement of plasticity along the evolutionary vector toward heat tolerance. The strongest response observed is the across-the-board down-regulation of a variety of genes occurring in heat-tolerant, but not in heat-sensitive clones. This response is particularly obvious among genes involved in core metabolic pathways and those responsible for transcription, translation and DNA repair.

Conclusions

The observed down-regulation of metabolism, consistent with previous findings in yeast and Drosophila, may reflect a general compensatory stress response. The associated down-regulation of DNA repair pathways potentially creates a trade-off between short-term benefits of survival at high temperature and long-term costs of accelerated mutation accumulation.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-859) contains supplementary material, which is available to authorized users.

Use of a concentrated enteral nutrition solution to increase calorie delivery to critically ill patients: a randomized, double-blind, clinical trial

BACKGROUND

Critically ill patients typically receive ∼60% of estimated calorie requirements.

OBJECTIVES

We aimed to determine whether the substitution of a 1.5-kcal/mL enteral nutrition solution for a 1.0-kcal/mL solution resulted in greater calorie delivery to critically ill patients and establish the feasibility of conducting a multicenter, double-blind, randomized trial to evaluate the effect of an increased calorie delivery on clinical outcomes.

DESIGN

A prospective, randomized, double-blind, parallel-group, multicenter study was conducted in 5 Australian intensive care units. One hundred twelve mechanically ventilated patients expected to receive enteral nutrition for ≥2 d were randomly assigned to receive 1.5 (n = 57) or 1.0 (n = 55) kcal/mL enteral nutrition solution at a rate of 1 mL/kg ideal body weight per hour for 10 d. Protein and fiber contents in the 2 solutions were equivalent.

RESULTS

The 2 groups had similar baseline characteristics (1.5 compared with 1.0 kcal/mL). The mean (±SD) age was 56.4 ± 16.8 compared with 56.5 ± 16.1 y, 74% compared with 75% were men, and the Acute Physiology and Chronic Health Evaluation II score was 23 ± 9.1 compared with 22 ± 8.9. The groups received similar volumes of enteral nutrition solution [1221 mL/d (95% CI: 1120, 1322 mL/d) compared with 1259 mL/d (95% CI: 1143, 1374 mL/d); P = 0.628], which led to a 46% increase in daily calories in the group given the 1.5-kcal/mL solution [1832 kcal/d (95% CI: 1681, 1984 kcal/d) compared with 1259 kcal/d (95% CI: 1143, 1374 kcal/d); P < 0.001]. The 1.5-kcal/mL solution was not associated with larger gastric residual volumes or diarrhea. In this feasibility study, there was a trend to a reduced 90-d mortality in patients given 1.5 kcal/mL [11 patients (20%) compared with 20 patients (37%); P = 0.057].

CONCLUSIONS

The substitution of a 1.0- with a 1.5-kcal/mL enteral nutrition solution administered at the same rate resulted in a 46% greater calorie delivery without adverse effects. The results support the conduct of a large-scale trial to evaluate the effect of increased calorie delivery on clinically important outcomes in the critically ill.

Genome-wide association studies of female reproduction in tropically adapted beef cattle

The genetics of reproduction is poorly understood because the heritabilities of traits currently recorded are low. To elucidate the genetics underlying reproduction in beef cattle, we performed a genome-wide association study using the bovine SNP50 chip in 2 tropically adapted beef cattle breeds, Brahman and Tropical Composite. Here we present the results for 3 female reproduction traits: 1) age at puberty, defined as age in days at first observed corpus luteum (CL) after frequent ovarian ultrasound scans (AGECL); 2) the postpartum anestrous interval, measured as the number of days from calving to first ovulation postpartum (first rebreeding interval, PPAI); and 3) the occurrence of the first postpartum ovulation before weaning in the first rebreeding period (PW), defined from PPAI. In addition, correlated traits such as BW, height, serum IGF1 concentration, condition score, and fatness were also examined. In the Brahman and Tropical Composite cattle, 169 [false positive rate (FPR) = 0.262] and 84 (FPR = 0.581) SNP, respectively, were significant (P < 0.001) for AGECL. In Brahman, 41% of these significant markers mapped to a single chromosomal region on BTA14. In Tropical Composites, 16% of these significant markers were located on BTA5. For PPAI, 66 (FPR = 0.67) and 113 (FPR = 0.432) SNP were significant (P < 0.001) in Brahman and Tropical Composite, respectively, whereas for PW, 68 (FPR = 0.64) and 113 (FPR = 0.432) SNP were significant (P < 0.01). In Tropical Composites, the largest concentration of PPAI markers were located on BTA5 [19% (PPAI) and 23% (PW)], and BTA16 [17% (PPAI) and 18% (PW)]. In Brahman cattle, the largest concentration of markers for postpartum anestrus was located on BTA3 (14% for PPAI and PW) and BTA14 (17% PPAI). Very few of the significant markers for female reproduction traits for the Brahman and Tropical Composite breeds were located in the same chromosomal regions. However, fatness and BW traits as well as serum IGF1 concentration were found to be associated with similar genome regions within and between breeds. Clusters of SNP associated with multiple traits were located on BTA14 in Brahman and BTA5 in Tropical Composites.

Bacterioplankton: a sink for carbon in a coastal marine plankton community

Recent determinations of high production rates (up to 30 percent of primary production in surface waters) implicate free-living marine bacterioplankton as a link in a "microbial loop" that supplements phytoplankton as food for herbivores. An enclosed water column of 300 cubic meters was used to test the microbial loop hypothesis by following the fate of carbon-14-labeled bacterioplankton for over 50 days. Only 2 percent of the label initially fixed from carbon-14-labeled glucose by bacteria was present in larger organisms after 13 days, at which time about 20 percent of the total label added remained in the particulate fraction. Most of the label appeared to pass directly from particles smaller than 1 micrometer (heterotrophic bacterioplankton and some bacteriovores) to respired labeled carbon dioxide or to regenerated dissolved organic carbon-14. Secondary (and, by implication, primary) production by organisms smaller than 1 micrometer may not be an important food source in marine food chains. Bacterioplankton can be a sink for carbon in planktonic food webs and may serve principally as agents of nutrient regeneration rather than as food.

Expression of AT1R, AT2R and AT4R and their roles in extravillous trophoblast invasion in the human

The placental renin-angiotensin system (RAS) is active from early pregnancy and may have a role in placentation. Angiotensin II (AngII) acts via binding to receptor types AT1R and AT2R. Recently smaller peptide members of the angiotensin family have been recognised as having biological relevance. Angiotensin (3-8) (AngIV) has a specific receptor (AT4R) and evokes hypertrophy, vasodilatation and vascular inflammatory response. The aim of this study was to characterise placental expression of AT1R, AT2R and AT4R, and to determine whether AngII and AngIV regulate extravillous trophoblast (EVT) invasion, apoptosis and proliferation. Placental samples were obtained from women undergoing elective surgical termination of pregnancy (TOP) at 8-10 weeks gestation (early TOP), 12-14 weeks gestation (mid TOP) or at delivery following normal pregnancy or with pre-eclampsia (PE). Immunohistochemistry and qRT-PCR were performed to determine placental mRNA and protein expression of AT1R, AT2R and AT4R at all gestational ages. EVT invasion following culture with AngII or AngIV was assessed in early placental tissue using Matrigel invasion assays. Invasion was assessed on day 6 of culture and placental explants were harvested for immunohistochemical analysis of apoptosis and proliferation. The results from qRT-PCR and immunohistochemistry showed placental AT1R expression which did not vary with gestation. The highest levels of expression of AT2R were found in early and mid TOP placentae compared to term pregnancy. Expression of AT4R was increased in term placentae, with a significant reduction in PE placentae. Moreover, culture with AngIV or AngII increased EVT invasion from placental explants, which showed increased trophoblast proliferation and reduced apoptosis. This study has characterised expression of AT4R and AT1R and AT2R in human placenta throughout normal pregnancy and in PE. Both AngIV and AngII may play an important role in normal pregnancy.

Differential expression and distribution of placental glutathione peroxidases 1, 3 and 4 in normal and preeclamptic pregnancy

Preeclampsia is a pregnancy-specific condition affecting 2-7% of women and a leading cause of perinatal and maternal morbidity and mortality; it may also predispose the mother and fetus to increased risks of adult cardiovascular disease. The selenoprotein glutathione peroxidases (GPxs) have critical roles in regulating antioxidant status.

OBJECTIVES, STUDY DESIGN AND MAIN OUTCOME MEASURES

Immunohistochemical measurements of GPx1, GPx3 and GPx4 protein expression were performed on samples taken from three standardised sampling sites between the cord insertion and the periphery of the placenta from 12 normotensive, and 12 preeclamptic women to establish if their expression differed between sampling sites. Total GPx activities were also examined from the three sampling sites of these placentae.

RESULTS

There were highly significant reductions in overall immunohistochemical staining of all 3 GPxs in the preeclampsia compared to normotensive placentae (GPx1: P=0.016; GPx3: P=0.003; GPx4: P<0.001). Furthermore, graded differences in expression between the standardised placental sampling sites were also found for GPx3 (higher in the inner region, P=0.05) and GPx4 (higher in the periphery, P=0.02) but not GPx1. Placental GPx enzyme activity was also significantly reduced in tissue from preeclamptic women as compared to normotensive women (P=0.007; the difference was more pronounced nearest the cord insertion).

CONCLUSIONS

We have shown highly significant reductions in expression of all three major classes of GPx in placentae from women with preeclampsia, and distribution gradients in activity, which may relate to the differential oxygenation of regions of the placenta.

Cantilever-based sensing: the origin of surface stress and optimization strategies

Many interactions drive the adsorption of molecules on surfaces, all of which can result in a measurable change in surface stress. This article compares the contributions of various possible interactions to the overall induced surface stress for cantilever-based sensing applications. The surface stress resulting from adsorption-induced changes in the electronic density of the underlying surface is up to 2-4 orders of magnitude larger than that resulting from intermolecular electrostatic or Lennard-Jones interactions. We reveal that the surface stress associated with the formation of high quality alkanethiol self-assembled monolayers on gold surfaces is independent of the molecular chain length, supporting our theoretical findings. This provides a foundation for the development of new strategies for increasing the sensitivity of cantilever-based sensors for various applications.

Decidual leucocyte populations in early to late gestation normal human pregnancy

Most research on human decidual leucocytes to date has focused on the predominant CD56+ uterine natural killer (uNK) cell population in early pregnancy. Few reports have documented decidual leucocyte populations after 13 weeks gestation and in late pregnancy. Placental bed (decidua basalis) and non-placental bed (decidua parietalis) biopsies from normal pregnancies were taken from women undergoing termination of pregnancy in the 1st and 2nd trimesters and following Caesarean section in the 3rd trimester. Immunohistochemistry was used to quantify the numbers of decidual cells expressing CD56, CD3, CD8, CD94, NKG2A and CD14 and double labelled CD161+CD3+ NKT-like cells. Although a significant reduction in CD56+ uNK cells was found in 3rd trimester samples compared with 1st and 2nd trimester decidua, a substantial residual CD56+ leucocyte population was identified in 3rd trimester decidua. Expression of the KIR CD94/NKG2A mirrored that of CD56 at all gestational ages, providing an explanation for the absence of cytotoxic responses at the fetal-maternal interface. There was no difference in leucocyte populations between decidua basalis and decidua parietalis. Double immunohistochemical labelling revealed small numbers of decidual CD3+CD56+ and CD8+CD56+ cells, which decreased in number at term, and CD161+CD3+ cells, which increased in number at term. No differences in leucocyte populations were detected between decidua parietalis and decidua basalis. In contrast to previous reports, a substantial residual CD56+ cell population was demonstrated in 3rd trimester decidua. Decidual cytotoxic T-lymphocytes did not alter in number during gestation, while in contrast CD14+ macrophages decreased at term, representing the smallest decidual population assessed.

Influence of birth weight on gene regulators of lipid metabolism and utilization in subcutaneous adipose tissue and skeletal muscle of neonatal pigs

Epidemiological studies suggest that low-birth weight infants show poor neonatal growth and increased susceptibility to metabolic syndrome, in particular, obesity and diabetes. Adipose tissue development is regulated by many genes, including members of the peroxisome proliferator-activated receptor (PPAR) and the fatty acid-binding protein (FABP) families. The aim of this study was to determine the influence of birth weight on key adipose and skeletal muscle tissue regulating genes. Piglets from 11 litters were ranked according to birth weight and 3 from each litter assigned to small, normal, or large-birth weight groups. Tissue samples were collected on day 7 or 14. Plasma metabolite concentrations and the expression ofPPARG2,PPARA,FABP3, andFABP4genes were determined in subcutaneous adipose tissue and skeletal muscle. Adipocyte number and area were determined histologically. Expression ofFABP3and4was significantly reduced in small and large, compared with normal, piglets in adipose tissue on day 7 and in skeletal muscle on day 14. On day 7,PPARAandPPARG2were significantly reduced in adipose tissue from small and large piglets. Adipose tissue from small piglets contained more adipocytes than normal or large piglets. Birth weight had no effect on adipose tissue and skeletal muscle lipid content. Low-birth weight is associated with tissue-specific and time-dependent effects on lipid-regulating genes as well as morphological changes in adipose tissue. It remains to be seen whether these developmental changes alter an individual's susceptibility to metabolic syndrome.

Bacterial delivery of a novel cytolysin to hypoxic areas of solid tumors

The efficacy of current anti-cancer gene therapies is limited by the inability of gene vectors to penetrate the poorly vascularized, hypoxic regions of tumors, leaving these sites untreated. We describe a new approach for targeting gene therapy to these sites, which employs an attenuated strain of the non-pathogenic bacterium, Salmonella typhimurium, carrying an exogenous (that is, reporter or therapeutic) gene under the regulation of a new, highly hypoxia-inducible promoter (FF+20(*)). This bacterial vector was seen to rapidly migrate into, and thrive in, hypoxic areas of both mammary tumor spheroids grown in vitro and orthotopic mammary tumors after systemic injection. Using the reporter gene construct, FF+20(*)-lacZ, we show that bacterial expression of high levels of beta-galactosidase occurred only in hypoxic/necrotic sites of spheroids and tumors. We then replaced the reporter gene with one encoding a novel cytotoxic protein (HlyE) and showed that this was also expressed by bacteria only in hypoxic regions of murine mammary tumors. This resulted in a marked increase in tumor necrosis and reduced tumor growth. Our system represents a promising new strategy for delivering gene therapy to poorly vascularized regions of tumors and shows, for the first time, the efficacy of HlyE as an anti-tumor agent.

Hypertension and impaired renal function accompany juvenile obesity: the effect of prenatal diet

Obesity has been suggested to have a detrimental impact on kidney structure and function, leading to focal glomerulosclerosis and hypertension. It is also associated with hyperleptinemia and elevated renal sympathetic nerve activity. Prenatal undernutrition promotes postnatal obesity, hypertension, and an altered renal structure and function. In this study, we examined the effects of prenatal nutrient restriction and juvenile obesity in sheep. We found that juvenile obesity led to chronic hyperleptinemia and reduced renal function as assessed by nuclear scintigraphy. Additional factors include hypertension, glomerulosclerosis, and increased kidney apoptosis. Prenatal undernutrition, synchronous with early kidney development, coupled postnatally with juvenile obesity had no effect on systemic pathophysiological sequalae associated with obesity per se. Hypertension, hyperleptinemia, and poor renal function were all observed in this group. All indices of renal pathology such as increased expression of proinflammatory cytokines, angiotensin II, glucocorticoid receptors, and increased apoptosis and glomerulosclerosis were entirely absent in obese prenatally undernourished offspring. Our data indicate that juvenile obesity per se leads to systemic hypertension and renal structural and functional pathology. Prenatal undernutrition effectively abolishes any renal histopathology associated with juvenile obesity.

Surface stress, kinetics, and structure of alkanethiol self-assembled monolayers

The surface stress induced during the formation of alkanethiol self-assembled monolayers (SAMs) on gold from the vapor phase was measured using a micromechanical cantilever-based chemical sensor. Simultaneous in situ thickness measurements were carried out using ellipsometry. Ex situ scanning tunneling microscopy was performed in air to ascertain the final monolayer structure. The evolution of the surface stress induced during coverage-dependent structural phase transitions reveals features not apparent in average ellipsometric thickness measurements. These results show that both the kinetics of SAM formation and the resulting SAM structure are strongly influenced both by the surface structure of the underlying gold substrate and by the impingement rate of the alkanethiol onto the gold surface. In particular, the adsorption onto gold surfaces having large, flat grains produces high-quality self-assembled monolayers. An induced compressive surface stress of 15.9 +/- 0.6 N/m results when a c(4x2) dodecanethiol SAM forms on gold. However, the SAMs formed on small-grained gold are incomplete and an induced surface stress of only 0.51 +/- 0.02 N/m results. The progression to a fully formed SAM whose alkyl chains adopt a vertical (standing-up) orientation is clearly inhibited in the case of a small-grained gold substrate and is promoted in the case of a large-grained gold substrate.

Application of a molecular method for the detection of group A rotaviruses in raw and treated water

Group A human rotaviruses (HRVs) are the most important aetiological agents of acute viral gastroenteritis in infants and young children in both developing and industrialised countries. Rotaviruses are resistant to many chemical disinfectants and reportedly survive well in treated tapwater and sewage. In this study a group A specific reverse transcriptase-polymerase chain reaction (RT-PCR) followed by a nested-PCR was applied for the detection of HRVs in raw and treated drinking-water samples drawn at a water reclamation plant. For a period of two years (July 2000 to June 2002), borehole, raw and treated drinking-water samples were collected weekly. Viruses were recovered from the water samples using a glass wool adsorption-elution technique followed by secondary concentration using precipitation with polyethylene glycol. In the first year of the study group A HRVs were detected in 11% sewage samples, 8% partially treated waters and 5% final treated drinking waters. The results of the second year of the study showed the presence of group A HRVs in 11% sewage and untreated surface water samples, 15% partially treated water and 6.5% final treated drinking waters. No HRVs were detected in the water samples from the boreholes. The presence of group A HRVs in treated drinking-water samples suggested that this water could be a potential source of infection to consumers. The data also implied that either the water treatment did not remove HRVs or the treated water was contaminated post-treatment.

Possible involvement of inositol phosphoglycan-P in human parturition

Preterm labour is a major cause of neonatal morbidity and mortality but the pathophysiology that underlies preterm labour is unknown. Inositolphosphoglycans (IPGs) comprise a ubiquitous family of putative carbohydrate second messengers and they have been linked to the pathogenesis of various conditions, including diabetes and pre-eclampsia. Studying IPG-P levels in normal and pre-eclamptic pregnancies, we noticed a constant rise of urinary IPG-P levels in all women at the time of delivery. A prospective pilot study of urinary IPG-P levels in 23 non-labouring and labouring women with uncomplicated pregnancies has, therefore, been performed. Levels of urinary IPG-P were significantly higher in labour than in the non-labouring group (P<0.0001). These higher levels have been found in both spontaneous and induced labour. The clinical significance of this observation with particular reference to the onset of labour itself is discussed.

Morphometrics and estimates of force generation by the chelae of a North American population of the invasive green crab,Carcinus maenas(L.)

The European green crab, Carcinus maenas, is an invasive species in eastern North America and has the potential to significantly impact wild and aquaculture shellfish in the southern Gulf of St. Lawrence, Canada. To examine potential predation effects on local shellfish and assess the appropriateness of extrapolating results from studies conducted elsewhere, the morphometry of chelae from a recently established population of C. maenas in Nova Scotia was examined for comparison with the presumed founding (European) population, and forces generated by the chelae over a range of crab sizes were estimated. The Nova Scotia population was found to be morphologically very similar to European populations with respect to chela structure. Force generation by the chelae was found to scale with isometry in the female crab and with positive allometry in the male. Estimated forces compare well with previously reported forces, and force generation is calculated to increase in a nonlinear manner proceeding from the chela tips proximally toward the fulcrum. The calculated forces generated by the chelae are clearly sufficient for outright crushing of some shells (e.g., Mya arenaria), even for small crabs, but appear to be too low for crushing those of other molluscs. There is a complex interplay between gape and maximum force along the length of the dactyl that allows great variability in force application, and thus also in the size of prey consumed and prey-handling behaviour. We suggest that for such a lever system, the gape angle of the chelae, which does not change with crab size, is optimal with respect to the resultant force generated.

A bone-seeking clone exhibits different biological properties from the MDA-MB-231 parental human breast cancer cells and a brain-seeking clone in vivo and in vitro

Breast cancer has a predilection for spreading to bone. The mechanism of preferential metastasis of breast cancer to bone is unknown. We hypothesize that breast cancer cells that develop bone metastases have the capacity to facilitate their colonization in bone. To examine this hypothesis, we established bone-seeking (MDA-231BO) and brain-seeking (MDA-231BR) clones of the human breast cancer cell line MDA-MB-231 by repeated sequential passages in nude mice and in vitro of metastatic cells obtained from bone and brain metastases, respectively. These clones were examined for distinguishing biological characteristics and compared with the MDA-231 parental cells (MDA-231P) in vivo and in vitro. Both the MDA-231BR and the MDA-231BO showed identical tumorigenicity to MDA-231P at the orthotopic site. MDA-231P that was inoculated into the heart developed metastases in bone, brain, ovary, and adrenal glands. On the other hand, MDA-231BO exclusively metastasized to bone with larger osteolytic lesions than MDA-231P. MDA-231BR exclusively disseminated to brain and failed to develop bone metastases. In culture, MDA-231BO produced greater amounts of parathyroid hormone-related protein (PTH-rP) than MDA-231BR and MDA-231P in the absence or presence of transforming growth factor beta (TGF-beta). Furthermore, the anchorage-independent growth of MDA- 231BO in soft agar was not inhibited by TGF-beta, whereas TGF-beta profoundly inhibited the growth of MDA-231P and MDA-231BR. Insulin-like growth factor I (IGF-I) markedly promoted the anchorage-independent growth of MDA-231BO, whereas marginal or no stimulation was observed in MDA-231BR or MDA-231P, respectively. Our data suggest that these phenotypic changes allow breast cancer cells to promote osteoclastic bone resorption, survive, and proliferate in bone, which consequently leads to the establishment of bone metastases.

The bisphosphonate ibandronate promotes apoptosis in MDA-MB-231 human breast cancer cells in bone metastases

Bisphosphonate (BP), a specific inhibitor of osteoclasts, has been widely used as a beneficial agent for the treatment of bone metastases in patients with breast cancer. It is well recognized that BP reduces osteolysis by promoting apoptosis in osteoclasts. However, recent animal and human data suggest that BPs not only reduce osteolysis associated with metastatic breast cancer, but also decrease tumor burden in bone. The mechanisms by which tumor burden is decreased following BP administration are unknown. Here we examined the effects of the BP ibandronate on MDA-231 human breast cancer cells in bone metastases in a well-characterized animal model of bone metastasis. Ibandronate, which was administered (s.c. daily; 4 microg/mouse/day) after bone metastases were established, inhibited the progression of established osteolytic bone metastases as assessed by radiographic analysis. Histological and histomorphometrical examination revealed that ibandronate reduced osteoclastic bone resorption, with increased apoptosis in osteoclasts. Furthermore, ibandronate also significantly decreased the MDA-231 tumor burden, with increased apoptosis in MDA-231 breast cancer cells in bone metastases. In contrast, ibandronate failed to inhibit MDA-231 tumor formation with no effects on apoptosis in MDA-231 breast cancer cells in the orthotopic mammary fat pads. These data suggest that the effects of ibandronate on apoptosis in MDA-231 breast cancer cells are restricted in bone in which ibandronate selectively deposits. Consistent with these in vivo results, a relatively high concentration of ibandronate (100 microM) increased caspase-3 activity and induced DNA fragmentation in MDA-231 breast cancer cells in culture. Moreover, a caspase inhibitor, z-Val-Ala-Asp-fluoromethyl ketone, blocked ibandronate-induced DNA fragmentation in MDA-231 cells, suggesting an involvement of caspase-3 in ibandronate-induced apoptosis. Our results suggest that BP suppresses bone metastases through promotion of apoptosis in metastatic cancer cells as well as in osteoclasts. However, it still remains open whether BP has direct anticancer actions in vivo.

Therapeutic efficacy of a soluble receptor activator of nuclear factor kappaB-IgG Fc fusion protein in suppressing bone resorption and hypercalcemia in a model of humoral hypercalcemia of malignancy

Receptor activator of nuclear factor kappaB (RANK) is a membrane-bound tumor necrosis factor receptor homologue that mediates signals obligatory for osteoclastogenesis as well as osteoclast activation and survival in vivo. The present study was undertaken to evaluate the efficacy of a soluble murine RANK-human immunoglobulin fusion protein (muRANK.Fc) as a bone resorption inhibitor in vitro and in vivo. The in vitro studies demonstrated the ability of muRANK.Fc to inhibit human parathyroid hormone-related protein (PTHrP)-induced resorption in fetal rat long bone cultures. Short-term administration of muRANK.Fc to normal growing mice resulted in a complete disappearance of osteoclasts from metaphyses of long bones associated with a pronounced increase in calcified trabeculae and bone radiodensity. In a model of humoral hypercalcemia of malignancy in which PTHrP secreted by s.c. xenografts of human lung cancer in nude mice induces extensive osteolysis and severe hypercalcemia, daily administration of muRANK.Fc from time of tumor implantation profoundly inhibited osteoclastic bone resorption and prevented hypercalcemia. muRANK.Fc had no effect on tumor production of PTHrP, because there was no significant difference between circulating human PTHrP levels in muRANK.Fc-treated and vehicle-treated tumor-bearing mice. Moreover, even when treatment was initiated after hypercalcemia was established, muRANK.Fc significantly attenuated further increases in blood ionized calcium. These data demonstrate the potent antiresorptive effects of muRANK.Fc in vivo as well as highlight the potential utility of disrupting RANK signaling as a novel therapeutic approach in humoral hypercalcemia of malignancy and possibly multiple myeloma and skeletal metastases associated with osteolysis.

Dichloroacetate: population pharmacokinetics with a pharmacodynamic sequential link model

Dichloroacetate (DCA) is a small molecule that reduces ambient concentrations of lactate in man. It was the purpose of this study to develop pharmacokinetic and pharmacodynamic models for determination of a dose for a pivotal Phase III clinical trial of DCA in patients with traumatic brain injury (TBI). Population pharmacokinetic and pharmacodynamic models were developed for DCA using NONMEM software. The pharmacokinetic data were fit to a physiologic two-compartment model, and the pharmacodynamic data were fit to an indirect physiologic response model. Simulations were employed to evaluate various dosing strategies for consideration in a pivotal Phase III clinical trial of DCA. For the pharmacokinetic model, it was discovered that the clearance of DCA decreased on multiple dosing from 4.82 L/h to 1.07 L/h and that the pharmacokinetics and pharmacodynamics in TBI patients could not be predicted from normal volunteers. Population pharmacokinetic modeling and simulation of the expected effects of several dosing strategies were useful procedures for designing a Phase III trial.

The role of population pharmacokinetics in drug development in light of the Food and Drug Administration's 'Guidance for Industry: population pharmacokinetics'

Population pharmacokinetics (PPK) has evolved from a discipline primarily applied to therapeutic drug monitoring to one that plays a significant role in clinical pharmacology in general and drug development in particular. In February 1999 the US Food and Drug Administration issued a 'Guidance for Industry: Population Pharmacokinetics' that sets out the mechanisms and philosophy of PPK and outlines its role in drug development. The application of PPK to the drug development process plays an important role in the efficient development of safe and effective drugs. PPK knowledge is essential for mapping the response surface, explaining subgroup differences, developing and evaluating competing dose administration strategies, and as an aid in designing future studies. The mapping of the response surface is done to maximise the benefit-risk ratio, so that the impact of the input profile and dose magnitude on beneficial and harmful pharmacological effects can be understood and applied to individual patients. PPK combined with simulation methods provides a tool for estimating the expected range of concentrations from competing dose administration strategies. Once extracted, this knowledge can be applied to labelling or used to assess various future study designs. PPK should be implemented across all phases of drug development. For preclinical studies, PPK can be applied to allometric scaling and toxicokinetic analyses, and is useful for determining 'first time in man' doses and explaining toxicological results. Phase I studies provide initial understanding of the structural model and the effect of possible covariates, and may later be used to evaluate PPK differences between patients and healthy individuals. Phase II studies provide the greatest opportunity to map the response surface. With these PPK models it is possible to gain an improved understanding of the role of the dose on the response surface and of the range of expected responses. In phase III and IV studies, PPK is implemented to further refine the PPK model and to explain unexpected responses. Planning for the implementation of PPK across all phases of drug development is necessary, as well as planning for individual PPK studies. Planning should include: defining important questions, identifying covariates and drug-drug interactions that need to be investigated, and identifying the applications and intended use of the model(s). The plan for each project must have a strategy for data management, data collection, data quality assurance, staff training for data collection, data analysis and model validation.

Cell-cell contact between marrow stromal cells and myeloma cells via VCAM-1 and alpha(4)beta(1)-integrin enhances production of osteoclast-stimulating activity

Myeloma is a unique hematologic malignancy that exclusively homes in the bone marrow and induces massive osteoclastic bone destruction presumably by producing cytokines that promote the differentiation of the hematopoietic progenitors to osteoclasts (osteoclastogenesis). It is recognized that neighboring bone marrow stromal cells influence the expression of the malignant phenotype in myeloma cells. This study examined the role of the interactions between myeloma cells and neighboring stromal cells in the production of osteoclastogenic factors to elucidate the mechanism underlying extensive osteoclastic bone destruction. A murine myeloma cell line 5TGM1, which causes severe osteolysis, expresses alpha(4)beta(1)-integrin and tightly adheres to the mouse marrow stromal cell line ST2, which expresses the vascular cell adhesion molecule-1 (VCAM-1), a ligand for alpha(4)beta(1)-integrin. Co-cultures of 5TGM1 with primary bone marrow cells generated tartrate-resistant acid phosphatase-positive multinucleated bone-resorbing osteoclasts. Co-cultures of 5TGM1 with ST2 showed increased production of bone-resorbing activity and neutralizing antibodies against VCAM-1 or alpha(4)beta(1)-integrin inhibited this. The 5TGM1 cells contacting recombinant VCAM-1 produced increased osteoclastogenic and bone-resorbing activity. The activity was not blocked by the neutralizing antibody to known osteoclastogenic cytokines including interleukin (IL)-1, IL-6, tumor necrosis factor, or parathyroid hormone-related peptide. These data suggest that myeloma cells are responsible for producing osteoclastogenic activity and that establishment of direct contact with marrow stromal cells via alpha(4)beta(1)-integrin/VCAM-1 increases the production of this activity by myeloma cells. They also suggest that the presence of stromal cells may provide a microenvironment that allows exclusive colonization of myeloma cells in the bone marrow. (Blood. 2000;96:1953-1960)

Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: their release during fermentation and lees contact and a proposal for their mechanism of action

A fraction containing the mannoproteins released during fermentation from the winemaking strain of Saccharomyces cerevisiae, Maurivin PDM, was able to reduce the visible protein haze in white wine. This fraction of haze protective mannoprotein material (HPM) could be recovered by either ultrafiltration or ethanol precipitation. The kinetics of the release of both mannose- and glucose-containing polymers during the growth cycle of PDM were determined as a guide to the release of HPM. Active HPM was first detected in the culture supernatant when the cells were exponentially growing. HPM was also released into the medium under an environment simulating winemaking conditions by PDM cells during fermentation as well as during storage on yeast lees. Since the amounts of HPM released during fermentation are greater than those subsequently extracted from the cell wall, fermentation would be a more viable procedure than extraction from yeast cells for the commercial production of HPM. Yeast invertase, a mannoprotein with haze protective activity, was used as a model substrate to investigate the mechanism of haze protection. Invertase was found to reduce visible turbidity but not prevent protein precipitation. Invertase itself did not precipitate but remained soluble in the wine. On the basis of these observations, we propose that the mechanism of haze protection may be one of competition between HPM and wine proteins for unknown wine component(s), the latter being required for the formation of large insoluble aggregates of denatured protein. As the available concentration of these components decreases, due to the presence of HPM, the particle size of the haze decreases and thus visible turbidity declines.

Actions of bisphosphonate on bone metastasis in animal models of breast carcinoma

BACKGROUND

Bone, which abundantly stores a variety of growth factors, provides a fertile soil for cancer cells to develop metastases by supplying these growth factors as a consequence of osteoclastic bone resorption. Accordingly, suppression of osteoclast activity is a primary approach to inhibit bone metastasis, and bisphosphonate (BP), a specific inhibitor of osteoclasts, has been widely used for the treatment of bone metastases in cancer patients. To obtain further insights into the therapeutic usefulness of BP, the authors studied the effects of BP on bone and visceral metastases in animal models of metastasis.

METHODS

The authors used two animal models of breast carcinoma metastasis that they had developed in their laboratory over the last several years. One model uses female young nude mice in which inoculation of the MDA-MB-231 or MCF-7 human breast carcinoma cells into the left cardiac ventricle selectively develops osteolytic or osteosclerotic bone metastases, respectively. Another model uses syngeneic female mice (Balb/c) in which orthotopic inoculation of the 4T1 murine mammary carcinoma cells develops metastases in bone and visceral organs including lung, liver, and kidney.

RESULTS

BP inhibited the development and progression of osteolytic bone metastases of MDA-MB-231 breast carcinoma through increased apoptosis in osteoclasts and breast carcinoma cells colonized in bone. In a preventative administration, however, BP alone increased the metastases to visceral organs with profound inhibition of bone metastases. However, combination of BP with anticancer agents such as uracil and tegafur or doxorubicin suppressed the metastases not only in bone but also visceral organs and prolonged the survival in 4T1 mammary tumor-bearing animals. Of interest, inhibition of early osteolysis by BP inhibited the subsequent development of osteosclerotic bone metastases of MCF-7 breast carcinoma.

CONCLUSIONS

These results suggest that BP has beneficial effects on bone metastasis of breast carcinoma and is more effective when combined with anticancer agents. They also suggest that the animal models of bone metastasis described here allow us to design optimized regimen of BP administration for the treatment of breast carcinoma patients with bone and visceral metastases.

Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: evaluation of extraction methods and immunolocalization

Yeast-derived haze-protective mannoprotein material (HPM) offers protection to white wines from commercially unacceptable turbidities. HPM extraction methods have been evaluated using three winemaking strains of Saccharomyces cerevisiae. Digestion with Zymolyase of cells pretreated with DTE and EDTA gave the greatest yields of active material. Heat treatment of cells with SDS also released active material but the quantities were low. Treatment of the cells in an autoclave or with a French pressure device was less effective. A detailed study was conducted on the strain Maurivin PDM. SDS was not necessary to extract HPM from PDM; boiling the cells for 5 min in Tris buffer was sufficient. HPM could also be extracted with EDTA during the pretreatment of the cells prior to Zymolyase digestion. The data suggest that HPM was noncovalently linked to other cell wall components and loosely associated with the cell wall. An immunological investigation showed that a specific mannoprotein with haze-protective activity, HPF1, was located primarily on the outermost and innermost layers of the cell wall.

Use of bisphosphonates for the treatment of bone metastasis in experimental animal models

Therapeutic effectiveness of bisphosphonates (BP) on bone metastases in patients with cancers including those of the breast and prostate has been well documented. However, there are still many important questions that remain unsolved or controversial. To obtain answers for these questions that are not readily addressed in a well-controlled manner in clinical studies, we have developed two animal models of bone metastasis (orthotopic and experimental). Using these models, we studied the effects of BP alone or in combination with anti-cancer agents on the metastasis of breast cancer to bone and visceral organs. In addition, we also determined the effects of BP on osteosclerotic metastases. We found that BP impaired the progression of bone metastases primarily through enhancing apoptosis in osteoclasts and breast cancer cells colonized in bone. In some situations, however, BP alone increased metastases in visceral organs including liver and adrenal glands. However, combination of BP with anti-cancer agents enhanced the suppression of tumour in both bone and visceral organs, leading to prolonged survival of tumour-bearing animals. Of potential importance, preventative administration of BP inhibited the development of eventual osteosclerotic bone metastases. These results suggest that BP exhibits diverse beneficial effects on osteolytic and osteoblastic bone metastasis and non-bone organ metastasis in breast cancer when administered appropriately. They also suggest that the animal models of bone metastasis described here allow us to produce clinically- relevant information that is useful for the design of optimal regimens of BP for the treatment of breast cancer patients with bone and visceral metastases.

Growth and dissemination of a newly-established murine B-cell lymphoma cell line is inhibited by multimeric YIGSR peptide

B-cell lymphoma frequently shows simultaneous dissemination to multiple organs. It also occasionally involves bone and causes osteolytic lesions. To study the mechanisms responsible for this capacity of lymphoma cells to grow in different tissue microenvironments and search for effective therapeutic interventions for this hematological malignancy, we established a new murine B-cell lymphoma cell line named MH-95. The tumor disseminated to multiple organs including the lung, liver, kidney, spleen and lymph nodes within 2 weeks after subcutaneous inoculation in nude mice. In addition, the tumor also grew in bone and caused osteoclastic osteolytic lesions. Thus, this tumor model mimics the behavior in many ways of B-cell lymphoma in humans. We studied the role of laminin, a major component of the basement membrane, in this model, since although it has been implicated in solid tumor metastasis, little is known about the involvement of laminin in the growth of B-cell lymphoma in bone and other organs. Immunohistochemical examination showed strong laminin expression in the stroma of the primary subcutaneous tumor and tumors in the bone and other organs. Systemic administration of the antagonistic laminin peptide YIGSR decreased primary tumor growth and tumor cell deposit in the bone, liver and kidney. In addition, the peptide also decreased apparent neovascularization in the tumor, suggesting that the peptide suppressed angiogenesis presumably due to inhibition of laminin binding to its receptors. These results demonstrate that the MH-95 B-cell lymphoma cells express laminin and suggest that laminin plays a critical role in the growth and simultaneous dissemination of tumor cells to multiple organs, similar to what has been described in solid tumors. The results also suggest that suppression of angiogenesis through interfering with laminin actions may be a useful adjuvant therapy for B-cell lymphoma.

Correlation between IgG anti-type II collagen levels and arthritic severity in murine arthritis

This study examines the relationship between the serum levels of IgG antibodies to heterologous and homologous type II collagen and the subsequent arthritic severity in a collagen induced arthritis model. Arthritis was induced in DBA-1 mice using intradermal injections of heterologous type II collagen in Freunds complete adjuvant, the time of arthritis onset was noted and the severity was monitored regularly. Serum samples were taken and IgG levels of anti-heterologous and homologous type II collagen were analyzed both pre and post arthritis onset. We observed that post induction/pre arthritic serum IgG anti-heterologous and homologous type II collagen levels showed a significant correlation (both p < 0.01) with the severity of the arthritis that subsequently developed. Mice with early arthritis showed a highly significant correlation (p < 0.002) between sera IgG anti-homologous type II collagen levels and arthritic severity, a lesser correlation was also apparent between anti-heterologous type II collagen titres and arthritic severity (p < 0.05). The high levels of correlation observed in this study between anti-type II collagen titres and arthritic severity before actual onset of arthritis, clearly suggest that the magnitude of the initial humoral response to type II collagen plays a crucial role in determining the resultant arthritic severity. This observation is only apparent due to the use of an arthritis susceptible inbred mouse strain, which removes variables such as H-2 restriction, antigen processing/presentation and possible complement deficiencies, and the early time scale of the analysed sera samples.

Inhibition of osteolytic bone metastasis of breast cancer by combined treatment with the bisphosphonate ibandronate and tissue inhibitor of the matrix metalloproteinase-2

Multiple steps are involved in the metastasis of cancer cells from primary sites to distant organs. These steps should be considered in the design of pharmacologic approaches to prevent or inhibit the metastatic process. In the present study, we have compared the effects of inhibiting several steps involved in the bone metastatic process individually with inhibition of both together. The steps we chose were matrix metalloproteinase (MMP) secretion, likely involved in tumor cell invasion, and osteoclastic bone resorption, the final step in the process. We used an experimental model in which inoculation of human estrogen-independent breast cancer MDA-231 cells into the left cardiac ventricle of female nude mice causes osteolytic lesions in bone. To inhibit cancer invasiveness, the tissue inhibitor of the MMP-2 (TIMP-2), which is a natural inhibitor of MMPs, was overexpressed in MDA-231 cells. To inhibit bone resorption, a potent bisphosphonate, ibandronate (4 microg/mouse) was daily administered subcutaneously. Nude mice received either; (a) nontransfected MDA-231 cells; (b) nontransfected MDA231 cells and ibandronate; (c) TIMP-2-transfected MDA-231 cells; or (d) TIMP-2-transfected MDA-231 cells and ibandronate. In mice from group a, radiographs revealed multiple osteolytic lesions. However, in mice from group b or group c, osteolytic lesions were markedly decreased. Of particular note, in animals from group d receiving both ibandronate and TIMP-2-transfected MDA-231 cells, there were no radiologically detectable osteolytic lesions. Survival rate was increased in mice of groups c and d. There was no difference in local enlargement in the mammary fat pad between nontransfected and TIMP-2-transfected MDA-231 cells. These results suggest that inhibition of both MMPs and osteoclastic bone resorption are more efficacious treatment for prevention of osteolytic lesions than either alone, and suggest that when therapies are designed based on the uniqueness of the bone microenvironment and combined with several common steps in the metastatic process, osteolytic bone metastases can be more efficiently and selectively inhibited.

Reduction in the incidence and severity of collagen-induced arthritis in DBA/1 mice, using exogenous dehydroepiandrosterone

OBJECTIVE

This study examined the effect of exogenous dehydroepiandrosterone (DHEA) on the onset, incidence, and severity of collagen-induced arthritis (CIA).

METHODS

DHEA was administered subcutaneously prior to arthritis induction in DBA/1 mice, and the severity of the subsequent arthritis was monitored. Serum levels of total IgG and IgG isotype-specific anti-murine type II collagen were measured.

RESULTS

Repeated administration of DHEA during arthritis induction delayed the onset and decreased the severity of arthritis in male and female DBA/1 mice. DHEA failed to have an observable effect on established arthritis. IgG isotype autoantibody levels were found to be decreased in the sera of DHEA-treated mice.

CONCLUSION

Administration of exogenous DHEA offered protection against the development of CIA. These data support the results of human studies in which low DHEA levels have been identified as a potential risk factor for the development of rheumatoid arthritis. These findings also highlight DHEA as a potential therapy worthy of further investigation.

Direct comparison of three methods for predicting digoxin concentrations

Three methods of determining digoxin population pharmacokinetic parameters were compared for their abilities to predict 118 measured serum digoxin concentrations (SDCs) in 49 patients. NONMEM software (version IV) was used to generate a residual and a weighted residual for each measured-concentration-predicted-concentration pair. Prediction error analysis was done by a maximum likelihood technique that accounted for several within-patient measures. Data analysis also included graphic observation of weighted residuals (WRES) and calculation of the mean WRES and median absolute prediction error. A further parallel analysis was also carried out on subpopulations with and without concurrent quinidine and congestive heart failure (CHF). Method III was without bias in all subpopulations studied and had the smallest WRES in all populations. Method I was without bias in the overall population, however, it underpredicted SDCs in patients receiving quinidine and in those with CHF. Method II underpredicted SDCs in the overall population, those receiving quinidine, and in patients without CHF. There were no between-method differences in precision as assessed by absolute prediction error.

Bias in murine IgG isotype immobilisation. Implications for IgG glycoform analysis ELISA procedures

This study investigates immobilisation of murine IgG in various ELISA procedures. Monoclonal murine IgG isotypes and polyclonal IgG from sera were studied. Similar binding curves to plastic were found for all four individual murine IgG isotypes. Single isotypes displayed different affinities for both protein A and protein G, in particular IgG1 was poorly and IgG3 strongly bound to both of these proteins. When mixtures of the isotypes were bound to either plastic, protein A or protein G, competition was observed in which IgG3 was dominant. Paradoxically, studies on the binding rates of single isotypes direct to plastic revealed that IgG3 had the slowest binding rate. Heating of bound IgGs resulted in significant but isotypically non-selective losses from the plates. The data demonstrate that despite obtaining equivalent individual IgG isotype binding curves, mixtures of IgG isotypes behave very differently, with competition for binding occurring even on plastic. The IgG isotype levels of murine sera were measured for individual mice, and the capture efficiency of each IgG isotype by protein A determined at different serum dilutions. Comparisons were made between the observed capture levels of IgG isotypes and their known serum levels. At all dilutions tested, greater than expected binding of IgG3, IgG2b and IgG2a was observed. At a serum dilution of 1/100 the binding of these three isotypes was increased 16-, 2.9- and 0.4-fold, respectively. These increases were balanced by a decrease in IgG1 binding which was the most prevalent serum IgG isotype. The results described above suggest that capture techniques are biased and unlikely to provide a coating of IgG isotypes that accurately reflects that of the serum. This bias is derived from the specificity of the individual isotypes for either protein A or protein G, and the errors further compounded by direct competition between isotypes whatever the capture surface. Induced coalescence of IgG3 may explain the latter observations.

Analysis of murine IgG isotype galactosylation in collagen-induced arthritis

The galactosylation status of IgG from both control and arthritic DBA-1 mice was determined by exoglycosidase sequencing and an anti-GlcNAc monoclonal based ELISA. Two to three weeks after arthritis onset mice with collagen-induced arthritis (CIA) showed a modest increase in IgG anti-GlcNAc reactivity against controls (0.644 +/- 0.080 and 0.530 +/- 0.087, respectively, mean absorbance +/- SEM n = 4) consistent with previous literature reports. However, the authors were unable to detect any significant changes in the galactosylation of purified IgG from arthritic and control mice using direct sequencing techniques (percentage G0 of 34.5% +/- 1.9 and 37.7% +/- 2.4, respectively, mean +/- SEM n = 4). It has been demonstrated that a correlation exists between percentage G0 and anti-GlcNAc reactivity for purified human IgG and sera samples, respectively; no such correlation was found for murine IgG and sera. The galactosylation of purified polyclonal murine IgG isotypes was analysed on a separate group of arthritic mice selected for their high anti-GlcNAc reactivities. No significant differences were observed between control and arthritic mice. Immunoglobulin G isotype specific differences were found, with IgG1 exhibiting the highest percentage G0 (45-48%) followed by IgG2a (27-37%), IgG3 (20-32%) and IgG2b the lowest (13-17%). The percentage G0 and anti-GlcNAc reactivity of purified IgG1 and IgG2b showed a narrow range of values when compared to those of IgG2a and IgG3 samples. Pooled sera from both arthritic and control mice was used to purify large quantities of IgG3. Which on analysis revealed a fourfold increase in anti-GlcNAc reactivity in the arthritic sample compared to control. Paradoxically these same IgG3 samples contained similar percentage G0 levels as determined by direct sequencing. The results suggest that IgG1 and IgG2b exhibit isotype selective oligosaccharide processing as little sample heterogeneity could be observed. These two purified IgG isotypes displayed a good correlation between percentage G0 and anti-GlcNAc reactivity; this was in contrast to IgG2a and IgG3. Immunoglobulin G3 from arthritic mice may have G0 oligosaccharides selectively paired together with no net increase in percentage G0. This observation is discussed in detail as is the role of agalactosyl IgG in murine type II collagen-induced arthritis.